Quote (zebraso)

By fluid I guess it means suspended on liquid.

Here is the image of liquid rust I had in mind:



It is possible to see the liquid dripping from the PVC drain in this excellent video by our friend Jeff:

Link

That photo begs so many questions. I believe that is a catch bucket under a leaky elbow fitting that has been doped up with no success. Where do you start with that? Is this pvc drain like the one elsewhere that simply drains onto the floor at a column? Then the problem here would be the water is just running onto the floor at the non-preferred spot. And is that a junction box that the water is running onto? And is that covered with pitch to keep the water out. What the hell is going on there? Is the rust primarily from the junction box? Not that it is not a problem. Is this the standard for maintaining this building? Maybe I am seeing things.

Edit: Someone watched one too many flex seal commercials. Anyway sealing threaded pvc fittings is not always as simple as it should be. Too much tape and they crack. Where is the documentation that shows these drain pipes were ordered to be installed to drain onto the floor. And how did they decide where they should go? Or did Joe the plumber do it under cover of darkness?

One more thing in the picture that I wanted to point out in that picture. Some sort of concrete chunk left clinging to the wall by a thread. So the slab cracked apart there after mostly pulling out of the wall and pivoted down.

Quote (zebraso)

That photo begs so many questions.

Agreed, it is disturbing. That is/was a junction box. If you watch the video you will see there is a bucket below to catch the runoff.

Quote (Reverse_Bias (Electrical))

clinging to the wall by a thread

It seems to be resting on something that is jutting out of the wall. It could be an illusion. Just what it looks like. Is that a drain for the planter? Is there a hole in the wall there after the site is cleared?

After more looking and comparing I think what see jutting from the wall is circled below in a different view. And what you see as the slab is a diagonal crack going up the wall. And it looks like the wall is partially collapsed here. Well that would be something.

Quote (Reverse_Bias)

One more thing in the picture that I wanted to point out

Thanks Reverse_Bias,
There was a conduit that ran along the wall feeding the light on the corner of the 8-foot wall and possibly also the water cooler at the corner of the pool deck. I'm sure that is what that diagonal line is.

Quote (zebraso)

a different view

Thanks zebraso
I see the lump sticking out, that appears to align with the hole in the CMU wall above. Looking at that 7 news image.

Quote (zebraso)

Is there a hole in the wall there after the site is cleared

The wall was also cleared.

Is it fair to say this is what we are talking about? (in my faint red circle)

Quote (zebraso)

Is it fair to say this is what we are talking about? (in my faint red circle)

I think the area circled is further west than the hole in the wall. The location of the hole in the wall was just west of the single cone where the hoses (since MWI supplies industrial pumps) run down the wall.

Quote (zebroso)

It seems to be resting on something that is jutting out of the wall. It could be an illusion. Just what it looks like. Is that a drain for the planter? Is there a hole in the wall there after the site is cleared?

After more looking and comparing I think what see jutting from the wall is circled below in a different view. And what you see as the slab is a diagonal crack going up the wall. And it looks like the wall is partially collapsed here. Well that would be something.

I had to enhance your image to see it, but I think it's there.

Quote (IanCA (Mechanical))

further west than the hole in the wall

Thanks, I was thinking that was a possibility. The perspective is pretty tough. Not sure. I agree it looks far away. It looks like it's halfway to the end of the wall but I can't quite say for sure if that's right, because the farther things probably appear not as far as they really are. I think that's correct as to the perspective. It's a bad angle.

Quote (Reverse_Bias (Electrical))

I have a feeling I am about to see all kinds of things. So I better stop. But I will just note that I did not really notice part of the planter wall is resting on the truck. I have a tough time seeing that diagonal line as conduit in your enhancement. But the boundary wall looks deformed to me. That just does not look very planar. And I don't mean like in those photos of units where is was claimed the floors were sagging when it was probably the lens.

"Liquid rust"?

Maybe. Maybe not.

I see a LOT of brown goo on top of what looks like a small transformer (not a junction box). I don't see evidence of how it got there from above. Nor do I see how it could have been generated by the POSSIBLE transformer inside.

Please stop "reaching", and come of with real evidence!


spsalso

It looks a little too much like ballast tar. But that's crazy too. I'll go with brown goop on that one.

Quote (zebraso)

I have a feeling I am about to see all kinds of things. So I better stop. But I will just note that I did not really notice part of the planter wall is resting on the truck. I have a tough time seeing that diagonal line as conduit in your enhancement. But the boundary wall looks deformed to me. That just does not look very planar. And I don't mean like in those photos of units where is was claimed the floors were sagging when it was probably the lens.

I might be over enhancing contrast so maybe it's just a dark spot on the wall. Don't think it would be that important to the collapse anyway

Quote (IanCA)

Thanks Reverse_Bias,
There was a conduit that ran along the wall feeding the light on the corner of the 8-foot wall and possibly also the water cooler at the corner of the pool deck. I'm sure that is what that diagonal line is.

Good spot, that pic shows down into the hole much better.

Quote (Reverse_Bias (Electrical))

just a dark spot on the wall

That post demo damage is farther to the west too. I had to find a photo back about 6 threads ago. It more than 2 cmu faux columns down from the still standing wall. So there is no deformation in the area of interest that would suggest a wall collapse. On a positive note there appears to be no tar buggy in that hole either.

Quote (spsalso)

I don't see evidence of how it got there from above.

If you watch the video you can see the liquid dripping from the PVC pipe.

Quote (spsalso)

Nor do I see how it could have been generated by the POSSIBLE transformer inside.

I'm pretty sure it was a chemical reaction between the salty water and the carbon steel box.

Quote (spsalso)

Please stop "reaching", and come of with real evidence!

FeCl2 + H2O -> FeO + 2HCl

Quote (IanCA (Mechanical))

I'm pretty sure it was a chemical reaction between the salty water and the carbon steel box.

If I leave a coffee can beside the kitchen sink for too long I get a rust ring. Salt not needed. I mean the water is dripping on the steel box and the flanges at the bottom are partially dissolved. It would be a miracle if there were no rust stains wherever that water drips and runs.

It is most likely a transformer deferring to electrical. Transformer boxes can have cooling vent holes in the top. So they might have covered those holes to keep the dripping water from entering. Did they use a brown garbage can lid? Maybe. That's code right?
And the stains on the white bucket are reddish brown.

Edit: closer look at video and it look like a rectangular enclosure that may have ventilation holes under a drip edge. The spots with water running down may be bridges created by iron oxide deposits to the drip edge. (Lot of conjecture). Probably designed for damp environments. NEC?

Corrosion problem areas
https://www.corrosionpedia.com/2/2017/corrosion/in...

A black swan to a turkey is a white swan to the butcher.

The competitor/comedian in me says don't, quit your day job.

1 kva xfrmr in a rainproof enclosure. Good job.

So the water drip is intentional to cool the transformer enclosure???

Notice the flexible metallic conduit to the right in the picture of the Rusty Old Box. There is also something electrical looking coming out on the left.

I think it most likely that it was supplying low voltage (12 or 24 V) for something, but there isn't enough field of view to puzzle that out.

IF the water-stuff dripping down was leaking from a planter, then MAYBE that transformer was supplying low voltage lighting in it. Alternately, it could have been supplying power for a low-voltage irrigation system for the planter.

spsalso

It's 1:1 right? or 2:1 with center tap use. Galvanic isolation to help prevent electrocution from whatever the load is most likely. There are LED power supplies that can be found in a similar looking box. But this ain't that AFAIK assuming it is the Schneider product (label).

I think the label shows 120 and 240 connections. It says for voltage X on lines... connect secondary.... (something like that)

From the catalog these are general purpose transformers and they come in several different versions for different voltage standards. The they are resin encapsulated (potted). So that is the thermal management (no air flow needed). Oh yeah this might be to convert 208 to 120/240 If you could read the original label then we would know. But I don't think these are low voltage.

Quote (Nukeman948)

The competitor/comedian in me says don't, quit your day job.

Thanks, I'll take that advice.
I agree, that transformer looks close. The top certainly looks closer than the 1416 series, but the item in the video doesn't appear to have a screw, or screw hole, at the bottom, dimples on the sides or flanges for wall mounting. And there is another box behind the rusty enclosure in the video.

Quote (spsalso)

Rusty Old Box

That's all I was trying to get to. Acknowledgment that the brown stuff is likely to be rust rather than simply goo.

Quote (IanCA)

[img https://res.cloudinary.com/engineering-com/image/u...]

When you hold the camera that close you can't see the flanges. More pics here:Link

The bottom is two pieces held on with three rusty screws. Dimples may have been added as a design change for the newer model year. Now, imagine the bottom access cover filling with water, rusting the corner you pointed out, and the one screw that holds that part of the cover on, allowing it to fall off. Or imagine anything you like. I'm not the one trying to sell a story. And I don't care who believes me when I'm not under oath.

I'm not sure what the details of NEMA 3R are but I would guess that this does not apply. There is weather (rain), and then there is whatever this is. There has to be a code violation here, I would think.

Quote (zebraso)

whatever this is

I think there is a possible explanation here, with hydrochloric or muriatic acid (muriatic meaning "pertaining to brine or salt") being the main concern:

As has been noted above, the effect of Cl- ions on CS corrosion mechanisms has been much less
widely studied than the effect of SO2. A high Cl- concentration in the aqueous adlayer on the metal
and high moisture retention in very deteriorated areas of the rust give rise to the formation of ferrous
chloride (FeCl2), which hydrolyses the water:

FeCl2 + H2O -> FeO + 2HCl, (8)

Notably raising the acidity of the electrolyte. In this situation the cathodic reaction (3) becomes
important, accelerating the corrosion process. The anolyte on the steel surface and in the pits that
have formed becomes saturated (or close to saturation) with the highly acidic FeCl2 solution. Both
the metallic cations and hydrogen ions require neutralisation, which occurs by the entry of Cl- ions,
but this leads to an increase in the Cl- concentration which intensifies metal dissolution, giving rise
in turn to the entry of more Cl-, which further intensifies the corrosion process. This attack
mechanism is fed by the corrosion products themselves (feedback mechanism), and it is sometimes
referred to as “autocatalytic"

The complete document is available here: Link

Very good. Thank you. So we are back with the marine environment. But not just that because there is likely more than just ocean spray as found in rain.

Check the following article:

https://www.youtube.com/watch?v=YZFzVlpPSyg

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Ian... great link.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Section 110.26(F)(1)(a) I think code says that pipe has to be 6 feet above the electrical equipment (transformer box) and outside of a 30" wide zone centered on box or as wide as the equipment whichever is wider. And 36" in front depth must be clear. If the pipe was more than 6' above the box a drip pan could be installed under it.

@Dik,

Thanks. In addition to the HCl here are a couple of details that caught my eye:

p8
The concentration of marine aerosol decreases with altitude.

Marine aerosol is comprised of fine particles suspended in the air (jet drops, film drops, brine
drops and sea-salt particles), solid or liquid, whose sizes vary from a few angstroms to several
hundred microns in diameter

p9
In Figure 4, Morcillo et al. note that the wind only needs to blow short time at speeds above 3 m/s in
directions with high entrainment of marine aerosol (they call them “saline winds”) for atmospheric
salinity to reach important values


[average wind speed at Surfside is above 10mph (4.47m/s)
https://weatherspark.com/y/18654/Average-Weather-i...

p13
The influence of the distance from the sea is one of the most important aspects of MAC [marine atmospheric corrosion] in coastal
areas. Empirically, it is known that the effect of the marine atmosphere



Unfortunately, CTS had a few design features that exacerbated these conditions.

Quote (zebraso )

Section 110.26(F)(1)(a)

"The equipment space mentioned in 110.26(E) pertains to specific electrical equipment. All switchboards, switchgear, panelboards and motor control centers shall be located in dedicated spaces and protected from damage. Dedicated equipment space is not required for all types of electrical equipment, just those mentioned above. While there is nothing wrong with having dedicated space for equipment such as safety switches (disconnects), motor controllers (starters), meter socket enclosures, and transformers, it is not required".

Unfortunately, the NEC rules for dedicated equipment does not apply to transformers.
This is a good example of building codes being a minimum standard that we can and should exceed.
While it would have been good practice to provide a drip pan or a simple deflector, it does not a appear to be a code violation.

Thanks. I see the intent there is for equipment that is to be operated, serviced or adjusted while energized. And then someone mentions that you might have to check the temperature or test voltages with the panel open, on a transformer. It has to do with working spaces. The transformer is electrically and physically protected so if it shorts out or catches on fire, it's good. And you should not have to test it in situ. If a problem is suspected slap another one in there and bench test it. I know people that will take a wiz in a parking garage when they have been bar hopping. Well Seinfeld comes to mind also. This unit is just in a bad location.

It's only in a bad location because it's under a leaky pipe. And the professional qualified maintenance personnel have apparently chosen a sub-optimal solution. Sorta like some PE's in San Francisco.

If someone decides they need to pee on it, that might turn out to be an unfortunate decision.


spsalso

It would be nice to know what is being drained. It could be a condensate line for all anyone knows. Why is it turned down right above the transformer. why is there a T right above it also? Cleanout? It looks like there is a rubber tube adapter off the T that may or not be clamped. Just not enough info to make any real conclusions about anything. But it looks pretty kluged. That's a handyman special whatever it is. And Ostroff asked why the electrical cable was pulled out of the stay. It looks to me like the pipe installer had to move it to get the pipe to clear. If the whole thing is just part of the leaking ceiling solution then this had no more thought behind it that the fiberglass panels stuffed up in the works.

"And Ostroff asked why the electrical cable was pulled out of the stay."

I can't find evidence of a "stay".

On the right side of the transformer, there is attached an unpainted section of flexible metal conduit (flex). It appears to be attached to the bottom side of the transformer with a 90 degree connector. I see no evidence that it is not secured to the box.

On the left, which I will presume is the low voltage output, appears to be some sort of white (painted?) piping assembly. It is attached to the transformer using some sort of tight radius 90 degree connector.

It is poor quality video.


spsalso

Quote (spsalso)

I can't find evidence of a "stay".

I just listened again and I think what he says is "clipped into place". It's a one hole strap.
It looks like the flex was damaged and got replaced but the new one was too short and didn't reach the strap. The connector is NOT considered support.
On the left is typical non-metallic liquid tight conduit and 90° connector. I'll bet they forgot the ground wire too.

348.30 (a), FMC (flexible metal conduit) shall be securely fastened in place by an approved means within 300 mm (12 in.) of each box, cabinet, conduit body, or other conduit termination and shall be supported and secured at intervals not to exceed 1.4 m (41/2 ft). Where used, cable ties shall be listed and be identified for securement and support.

So yeah, typical "handyman" poor workmanship.

Jeff was also way off on the location. There is no corner parking spot in the area he was pointing to.

He was assuming that anything electrical such as this box would be centrally located. I would venture a guess that this transformer could be anywhere because it only 1 1kva max. Not enough for a blow dryer.

Nukeman948,

Your comments got me looking again at the video, and I have now seen the strap. That implies that an earlier installer was much more competent than the final one.

I do wonder how it came about that the flex needed replacement. Usually it's the transformer than needs replacement, and you re-use the flex--just swing it out of the way, to the right.

So, where in the garage would there be a need for a small transformer, and also be near a pipe that might leak some sort of liquid? Certainly the walls weren't covered with such pipes (or transformers). And the pipe WAS located at a wall, though it could have done other things in the unexamined area higher up.

I still think this transformer was providing low voltage for something related to the planters.


spsalso

Quote (zebraso)

Not enough for a blow dryer.

Doesn't make much sense to assume most electrical stuff would be centrally located to me. No logic to his train of thought. Especially when we know the main electrical room was in the North-West corner.
8.3 amps @ 120v is plenty of power for an automatic lawn sprinkler system. Nothing but timers and solenoids in those older systems. They often ran 3/4" white PVC distribution lines too. What does that "T" look like to you? A solenoid perhaps?
Only one place with a corner parking spot that I see on the drawings. North-East corner.
208v 20 amp three phase power for the exhaust fan in that same corner would leave plenty of excess current to feed that transformer. Perfect location for a sprinkler system for that nicely landscaped BBQ area to the East of the building.
All speculation of course.

https://res.cloudinary.com/engineering-com/image/upload/v1644871599/tips/APTOPIX_Building_Collapse_Miami_53686_sq37ov.webp

Edit: Another pic... Flex, wires and some boxes but no pipes or transformer.

Quote (spsalso)

I do wonder how it came about that the flex needed replacement.

The same water issue that rusted the transformer would destroy the flex as well, but flex is cheap and that transformer is over $500. Maintenance man could replace the flex but may not want to tackle a transformer.

Quote (Nukeman948 (Electrical))

What does that "T" look like to you? A solenoid perhaps?

Interesting possibility. So then the transformer and plumbing could be associated. That could be a simple explanation for some things that otherwise look bizarre. I could figure out more reaching around there in the dark than I get from that video. Which cable looks like the primary/secondary? If the secondary were on the right it would make some sense feeding up to a solenoid or controller. Since there is a junction box to the left it might be going there. I assumed the secondary was on the left but could be wrong.

Edit: I had not seen your photo yet. Wow. Transformer could have been knocked off the wall. Not as protected by overhang.

It's hard to fully comprehend what goes through the mind of Maintenance Man.


spsalso

HMMM

Quote (zebraso)

Which cable looks like the primary/secondary?

Ummm... No idea. Transformer and plumbing could be related, or it could be a condensate line. But I can't think of why they would have anything with a condensate drain in that area. Any other kind of drain should be larger unless it was engineered by the maintenance guy.

All the old conduits didn't survive site cleanup so there is nothing to follow to try and understand what the intent was. There is no way of guessing how many changes were made or why over the years. The only conclusion I have is that the average person has no clue how to take a decent video. Closeups don't show the big picture and most people pan way too fast.


Red pipe is likely fire sprinkler, question mark could be exhaust fan inlet but not sure. Grd, no idea.
Edit: red pipe is definitely fire sprinkler. It's Kilsheimers pic #0295 if you want to zoom in yourself.

Yeah, That's good. If nothing else to note, that rebar looks pretty rusty.

Definitely could be connected to an exhaust fan >>

NE corner shows an overturned fan in the grassy area.

Quote (Nukeman948 (Electrical))

There is no corner parking spot in the area he was pointing to.

He must have missed the .5 seconds that showed the right angle wall (or whatever angle the "corner" is). Are there any other corner parking spots this could be than NE or SW? west of ramp? There were lockers in the SW corner right? Assuming NE the rust stains were blasted with the paint. none of these corners would have water running out to the from a leaky pool deck. Just saying that dripping water must just be a thing there that is ignored/tolerated.

Exhaust fan at 60? I think there is a 45 in that corner so that does not natch up with the transformer video. The 45 is in front of the car.

Quote (zebraso)

Are there any other corner parking spots this could be than NE or SW? west of ramp?

Both West corners are rounded. Other East corner has the pool.
West of ramp is the only other possible location I see but without better as-built drawings I can't rule it in or out 100%.
Video from CTN show it wide open under the ramp with the generator fuel tank and transformer oil tank located there.
Morabito's drawings show a maintenance area under the ramp at CTS but there is not enough detail to know if it's enclosed or not. So I can't rule out West of ramp, yet.
Not sure if it really matters either way.

Quote (zebraso)

Exhaust fan at 60?

Yes, there is an exhaust fan in that "rounded corner" also. It is the South-West corner.
That big thing on the wall I believe is an access port where the natural gas connection for the new generator would have been if the 40 year rehab thing happened.

No much point to it other than trying to get a different glimpse of the pvc plumbing. Was it draining any outdoor deck exposure? I have to look at the whole walk-through again. BTW I think condensate is be pretty corrosive similar to DI water. It might not strictly fit "corrosive" but it dissolves metal over time and creates it own chemistry in the process. But salt would be worse. I think. I just don't think condensate would create the corrosion that is on that transformer. I have condensate running into my pitted cast porcelain deep sink and I don't see rust.

I am leaning towards apace 82. I don't see that small step curb at the perimeter.

Edit: except there is no wall in front of 82. Are we sure that transformer is in CTS? lol.

Slightly interesting. The catch pan leads downward to a pipe of which I don't know the purpose but it looks grey. spot 107 has a wall to the right of it. So it fits the transformer video. I mean what are the chances of finding a deck drain pan leading to a pipe that could (maybe) lead down to the transformer - assuming this is the location of course. One of the conjectures made by Ostroff was that water was simply following the pipe. There are still huge unknowns, but what are the odds of even finding this? I've had about enough of it though.


Edit: If I am not mistaken this catch panel is under the front driveway and the room on the other side of the wall is under landscaping. So this is not related to the collapse, other than to say well there were leaks the front also. But that was already commented on by Ostroff when he voice tracked the walkthrough I believe referring to where water was found on the floor. If anything I can't quite figure why there is much water coming in from the from front drive because it has cover. Or am I all wet? Is irrigation water running onto the drive?

Edit2: Ostroff noted the catch pan also and the water below it. I just happened to notice there was a wall beside space 107 which makes it fit the transformer video. It doesn't prove the audi in the transformer video was in spot 107. And I can't really see how the things in that video are on the wall in the walkthrough video, because there are no facility connections coming down the wall that I can see. So it's probably not there. I'm not saying that it's there.

Quote (thermopyle2.1)

I was looking forward to reading that.

Quote (zebraso)

Are we sure that transformer is in CTS?

I wondered the same thing, but Jeff mentions that the video was shot by Raysa Rodriguez, who was the owner of a unit in the portion that remained standing. So it seems quite likely.
Thanks for all the effort in tracking this down.

Here's another reference (emphasis added):

"Marine concrete" is all concrete that will be in contact with
seawater or brackish water, tidal variations, splash, or spray from
water in navigable waterways. Piles driven on land that extend below
the water table that contains saltwater or brackish water shall be
designed as marine concrete. Components of a marine structure that
are permanently buried in soil shall be considered marine concrete.
In addition, structures may need to be designed using these criteria
even though they are not adjacent to the waterfront. For example,
structures located several hundred yards from the waterfront often
deteriorate prematurely due to salt spray and salt fog brought to the
structure by prevailing winds. An assessment of existing structures
near the construction site can be an excellent indicator for the
Engineer of Record and Owner to decide if the proposed structure
should follow the guidelines for marine concrete.

From here: Link

Quote (dik)

catch the link:

https://www.understanding-cement.com/sulfate.html

@dik, I was wondering whether sulfates would really be an issue in Surfside with that fresh sea breeze.

https://www.transportenvironment.org/discover/crui...
https://www.wlrn.org/news/2021-02-03/at-portmiami-...
https://archive.ph/puSt9

"Luckily, the dangerous fumes that can cause serious illness are largely blown away [where?] by Miami’s famous ocean breezes."

But the results for SO2 results for L086-0019 look low even in 2019 & 2020 before COVID.
https://floridadep.gov/air/air-monitoring/content/...

This might seem too obvious, but was the irrigation schedule controlled by contracted pros, or was it a set and forget thing by the people that stuck those drip pans up in the pipes. And I wonder how you design a planter drain that does not clog. Mine fill with water even if they are empty just from wind blown debris. Is there something special about the drains?

Quote (IanCA)

I was looking forward to reading that.

IanCA, thanks, and you still can, if you want to open it on a desktop or laptop computer. I could not open link on my phone. I felt it was 'Out of Phase' with current topic, and just raising the noise floor of current discussions.

Quote (IanCA)

@dik, I was wondering whether sulfates would really be an issue in Surfside with that fresh sea breeze.

IanCA, I realize this question was for dik, but I have some thoughts for consideration.

We know from core samples that the interior portion of the structural slab was the part that looked powdery like gypsum. In addition, we know from Morabito's Mechanical Engineer inspection, at least two exhaust fans needed repair (belts and bearings).

I annotated in thread 15 on Morabito's Drawings where the 4 exhaust fans were located. The only air intake I see on plans for exhaust fans is thru the entrance gate to the parking garage.

If you look at the location of fresh air intake from garage gate source to the 4 exhaust fan locations, that results in a stagnant air flow area at South wall from around pool room doors on east side, and along south wall towards the west, where slab to wall connection appears to have failed first.

There is a pool room exhaust fan that is ducted from pool room to planter above structural garage roof deck. The only air intake for that exhaust fan appears to be either a gap between the pool and the East retaining wall, or perhaps a louver in pool room doors to pull air into pool room. This exhaust system is separate in function from the other 4 exhaust fans.

What about auto tail pipe emissions in parking garage and sulfates like sulfuric acid? I believe diesels produce more sulfuric acid at tail pipe than gasoline engines.

We know there was Great water source on top of garage ceiling structural slab.

Point is could the interior change of state concrete layer be due to tail pipe emissions and poor exhaust fan layout and maintenance such that a lot of tail pipe emissions were staying in garage for extended periods to react with interior layer of concrete?

Could we have multiple things going on as far as acid and base reactions at different locations?

Looking over the building plans, the only place that the nasty looking transformer could be is in the NE corner, on the north wall. I base that on the near internal right angle in the wall, the direction of the parked cars, the reflections of the ceiling lights, the placement of one of the columns and the lack of cars parked in the distance, behind the black one.

From the electrical drawing, the only thing in that corner is a three-phase exhaust fan. It is called 3600W in one location and 2HP in another. It is fed by a three-pole 20A circuit breaker. Aside from the ceiling lighting, there was nothing else there on the plans.

The only reason I can think of for a transformer at all is to, uh, transform. Thus, whoever installed that transformer did NOT need 208 three-phase, but something else. It is common not to run a neutral in a circuit designed only for a three-phase load, so that means there was no source for 120V at that location (other than the nearby lighting circuit!).

So, yes, they could have wanted 12/24V. Or they could have wanted 120V.

I will point out that there was a surface mounted 4" square box, to its left, with a blank cover. And a pipe leaves vertically from that box.


Up above this location was a patio/planting area. In examining the plans, I found no indication that an automatic irrigation system was planned or installed. What with that leak, and this transformer where there wasn't one on the plan, I'm still inclined to think we are looking at parts of an added on irrigation system for the garden area above. The leak may have been from the piping system itself, or a failure in the controls that dumped too much water into the planting area, from which it then leaked by a convenient route.

It's a real reach to blame the brown stuff (probably rust, but not for sure) on the pool, or the pool deck membrane, or exposure to salt water or sea air.


spsalso

Quote (thermopyle2.1)

The only air intake I see on plans for exhaust fans is thru the entrance gate to the parking garage.

Agreed, I came to the same conclusion and based on the information presented in my post on 14 Feb 22 00:34 we know "The concentration of marine aerosol decreases with altitude." or phrased another way we know the concentration of marine aerosols is highest at ground level.

Quote (thermopyle2.1)

The only air intake for that exhaust fan appears to be either a gap between the pool and the East retaining wall, or perhaps a louver in pool room doors to pull air into pool room.

Agreed and I understand that HVAC best practices dictate a negative static pressure in pool equipment rooms adjacent to occupied spaces to ensure that air is drawn, with added vehicle exhaust fumes, from the garage space occupied by residents while parking their vehicles, into the pool equipment room, rather than vice versa.

The warmed exhaust air from the pool equipment room is then vented upwind (relative to the prevailing wind direction) from the planter at the edge of the parking deck.

@spsalso
Thanks very much for your detailed and systematic evaluation of that condition.

Quote (spsalso)

probably rust

If it's not rust, or some similar iron-based corrosion product, how do you explain the hole in the corner of the enclosure?

Quote (spsalso)

It's a real reach to blame the brown stuff (probably rust, but not for sure) on the pool, or the pool deck membrane, or exposure to salt water or sea air.

I'm simply trying to establish that some corrosive liquid was present in the structure. I will go on to propose what I consider likely sources, I welcome you making alternative suggestions or disproving my suggestions.

The picture quality isn't so wonderful that I can truly tell whether there's a hole there or not. Same for the brown stuff.
Maybe the hole, if that's what it is, was caused by something other than the brown stuff.

If it's rust, and the flex was replaced because it was horribly damaged by rust, how did that happen? Could this collection of crap be related to anything other than an irrigation setup? If so, what?

If it's related to irrigation, then I'm assuming there was a long term water problem that happened right above, either a few inches or a few feet. And repairs were, uh, not wonderfully done.

So this establishes the abilities of Maintenance Man, but it doesn't tie in very well to a building falling down; said falling happening on the other side of said building.

Einstein: "Spooky action at a distance."


spsalso

Or it could be PCB leaking from an old abandoned transformer. I had a very old doorbell transformer that leaked brown oil just like we see in the photo you’ve been looking at. If it’s leaking old transformer oil, it’s very corrosive and could account for the damage we see in this funky oddity.

Quote (thermopyle2.1)

Fans again

I found a total of six fans with enough capacity for six air changes per hour. Many fans I've seen have two belts so if one is damaged or missing it will still function at a reduced capacity. There should be somewhere you could look up how many cfm of vehicle exhaust to expect from a 120 space parking deck. Then you would have to estimate what the concentration of corrosive contaminants would be. Seems like this might be a problem in every other parking garage there is. Is this one somehow different from all the rest?

Quote (MaudSTL)

If it’s leaking old transformer oil...

That is a dry transformer. It has no oil to leak out. They are embedded in epoxy resin.

Quote (Nukeman948)

I found a total of six fans with enough capacity for six air changes per hour.

HaHa! Yes Fans again! I found six (6) as well in garage. Storage Room, Pool Room, and Four (4) for garage parking area.
I liked IanCA's point about the pool exhaust fan was exhausting into the prevailing wind. It is a 1/4 HP 1945 CFM fan that is competing against Four (4) Two(2) HP 12000 CFM fans, and one 1/2 HP 4000 CFM fan for air intake from their shared parking garage gate area. So 52000 CFM fans and their little brother at 1945 CFM, and little brother has the static pressure of duct work to overcome as well.

I wonder how much negative static pressure that 1/4 HP motor is gonna pull on pool equipment room against the 5 other much larger fans? Especially with the 1/4" exhaust having to over come prevailing winds?

And who wants to bet the pool equipment room doors are not always shut?

It's funny how you keep finding more fans, right after I point out you missed one.

I'd like to see the math on how much static pressure those fans create with that huge hole at the ramp being wide open. Must be like dividing by zero.

Nukeman948, I am sticking with six until u tell me there is another one ☝️.

You make a great point on static pressure.

Quote (spsalso)

Could this collection of crap be related to anything other than an irrigation setup? If so, what?

Everything has a good explanation.

The aerial drift of salt-laden water droplets that are deposited on trees and shrubs causes salt spray damage. When droplets evaporate, the salt’s sodium and chlorine ions can penetrate stems, buds and leaves, causing direct damage.
Maintaining appropriate soil fertility and moisture conditions to reduce additional stresses, and to help combat desiccation.
Leaching the soil with thorough irrigation after salt exposure. Flush salt through the soil by applying 2 inches of water over a 2-3 hour period, stopping if runoff occurs. Repeat this treatment three days later if salt levels are still high
https://www.urbanforestry.frec.vt.edu/STREETS/docu...

@MaudSTL,
One of the main reasons I'm working on this is because I want to help discover, and share, all of the potential engineering risk factors involved with this incident. Would you be interested in starting a new spreadsheet that we could use to document the potential risks? The items on the list may not have been directly or indirectly involved with, or responsible for, the collapse, but they could be important for helping to avoid future incidents for other structures.

For example, I am thinking about topics such as concrete cover over rebar, column load rating, spans, marine exposure, thermal expansion, waterproofing, maintenance. I think there is a long list that many of the members here have good knowledge of and it would be helpful to have them organized in one place.

I am familiar with your CTS collapse spreadsheet posted 25 Jul 21 17:20, but I suspect that is difficult to contribute to because it may require the explanation of multiple complex factors, but the individual risks can be considered independently and may be easier to agree upon. The headings could be: risk factor, evidence, conditions, category, identification & monitoring methods, proposed mitigation.

What do you think?

Quote (IanCA (Mechanical))

Everything has a good explanation.

For example here is the flex that is feeding the fan in SW corner. It is running up from low on the wall. And yet again there is a drip tray running over to the wall so the water can track the cable to it's source. If the transformer video image was mirrored this could be the spot but it's not because the escutcheons on the care are correct. So I guess one just has to imagine this in the NE corner. But that would mean water is on the floor there as well. One question is if this fan is 3 phase does, it make sense that the cable would be coming from down on the wall. For example it would not need a transformer. per se. But is it a wet location thing to use one for isolation? Just more dumb questions.


Edit: I just realized that where the flex disappears a bit up high, that three phases could be going to the fan and one phase down to another mystery transformer. There is always a piece missing.

The drip tray looks to be on the near side of the first column away from the wall. And the "flex" is on the wall. Don't see how water from the former could get to the latter.

It seems extremely unlikely that that is flex, anyway. IF it's supplying the fan, it would have been installed by AT LEAST a drug-crazed apprentice, who would have used conduit. 'Cause it's already straight. And easier to pull. And you don't HAVE to pull a ground wire.

I think it more likely that it's a half-assed water line, used for my latest hobby-horse, planter irrigation. There's an isolated planting area just above.

As I mentioned earlier, you can't use one phase of 208 3-phase without a neutral. And there aren't too many electricians who throw in a free neutral when they're supplying a 3-phase motor. I have, but then I'm a thoughtful and considerate guy.

spsalso

Yeah I saw the tray goes to the column. But I thought there was another frame that showed a tray extending back along the side of the column. Anyway there are so many drip trays if you step through that walkthrough that there are likely more than one resting on a pipe or conduit at a wall. I wasn't saying there is another rusty transformer necessarily or even another transformer here.
If you use 1 phase of 208 with a neutral it would be 120 right? What your saying is you have to run another line with a neutral. And a free neutral would be an "illegal" ground. How would you get 208 to a transformer and why would anyone do that if they could just run 120 separately?

Edit: I realize 208 is 120*3^(1/2) and where that comes from.

"If you use 1 phase of 208 with a neutral it would be 120 right?"

Yes

"What your saying is you have to run another line with a neutral."

I am saying, minimally, you have to add a neutral wire. Whether or not you have to run another hot ("another line") can be a matter for discussion. But without a neutral, you don't have any 120V.

"And a free neutral would be an "illegal" ground."

I'm not sure what a "free" neutral is. It is VERY BAD FORM to use the ground as a neutral. Only Maintenance Man's younger brother would do that, which is why he is only hired for summer work installing insulation in attics.

"How would you get 208 to a transformer and why would anyone do that if they could just run 120 separately?"

If you've got 208 three phase at a location, you can use TWO of those wires, which gives you single phase 208. A transformer can then be used to step it down to 120V. (Or 24V. Or 12V.) What it does NOT give you is a grounded neutral. The reason why one might do this transformer thing is that you have ONLY 3 phase at your work location and it is a long way over to a source of 120V. With that transformer, now you do--pretty much what happened in our brown-topped example in Florida.

I'm not too interested in exploring possible code violations when some DOES do the above. I'm talking more about physical reality.

If I was a building inspector and found such a thing, I might let it pass for a light duty "control system" or something. Maybe. If it didn't look dangerous. Perhaps.

When I do typical industrial stuff, I do separate systems for the three phase and the single phase. I don't mix them. I DON'T do that thing above. If I need 120V, I take it off of the single phase 240V/120V system. And I do that even if I'm doing 240V three phase. I DO tend to run a neutral with the three phase, because once in a great while, someone will buy new equipment that includes some little bit of 120V. It's happened. Once or twice.


spsalso

Quote (spsalso)

If I need 120V, I take it off of the single phase 240V/120V system.

This building didn't even have a 240v/120v system.

Got it. You make a lot of sense. And I think I understand the mind set of maintenance guy's little brother. Code violations her per se are not too interesting. But if little brother is running loose it could be a factor in "something".

Quote (Nukeman948 (Electrical))

This building didn't even have a 240v/120v system

Wait, what? So there is no neutral in the building back to the wye? I think I see how that would work.

Quote (zebraso )

So there is no neutral in the building back to the wye?

I didn't say that. Every 120v circuit in this building has a neutral that goes back to the wye.
Edit: here's a hint, 120/240 volt systems don't have a wye.

Ok I misunderstood 240/120. Errr.

edit: i.e. there is no dedicated 240/120 entrance. Slight vernacular problem on my end.

Nukeman948,

Nowhere did I say THIS building had a 240/120V option.

In my last paragraph, you will notice I used the term "...typical industrial stuff,...". THAT would not apply to THIS building. "Typical industrial stuff" is usually 240V Delta (or 480V, etc), and DOES usually have 240/120V single phase available.

zebraso,

In THIS building, there are three hot wires and one neutral. Across any two hot wires is 208V single phase. Across any single hot wire and neutral is 120V single phase. Most of the heating devices in the building used the 208V single phase. These would be electric ranges and dryers, especially. There was also 3 phase power, integrally included, which needs to use ALL the hots (and no neutral). This could, and did, supply various motors throughout the building. It could also supply "non-residential" heating systems, but I don't think there were any.

What is neat about the above system is that, not only do you get three phase, but the supply is fully symmetrical. When you wire stacks of apartment units, or you alternate floors, you just keep going 123123123123...

What you DON'T get is 240V single phase. The OTHER style of three phase WILL give you 240V single phase, but on only two of the three wires.


Anyway. It ain't easy to get it all first time out. But it DOES make sense. Generally, 208V three phase is used in large apartment buildings, and 240V three phase is used in industrial buildings.


spsalso

Quote (spsalso)

Nowhere did I say THIS building had a 240/120V option.

I apologize for misunderstanding you.

I'm also fully aware of "Typical industrial stuff" and their voltages.

We have a reactor cooling pump motor replacement coming up this outage and need more workers if you're interested. It's only 6000hp and 12.5kv. It might be too small of a project for you though.

I'm booked up for awhile, but it does sound interesting.

What happened to the old one, that it needs replacing?


spsalso

Quote (spsalso (Electrical))

It ain't easy to get it all first time out. But it DOES make sense.

Thanks, I wouldn't be asking stupid question if I had the prints in front of me. I know you guys have looked at it.
There used to be a small industrial manufacturing out building across the street from me. They had 3 phase 240 (a+b) going in there from the same lines that fed the residential blocks and same sized center tap pole transformers as residential. What I have to absorb is that is not 3 phase 208 (the difference). They had some equipment related to textile industries that go back to the mid 20th century. But then again it was an outbuilding. The main buildings had a different feed and was about 100 yards away. One of those transformers also fed the street lights. A lot of context. Anyway, thanks for the edumucation.

Edit: Other than that I understand there is no A/B until the center tap comes into it. So the single phase street lights were returned to neutral/center tap. and 240 three phase went into the building. That would have to be delta also. but I never looked that close.

Edit2: And funny I once worked in a coil/transformer shop in engineering. A long time ago. Not a lot of 3 phase but doesn't mean I recall all the theory either. Forgive my stupidity. Small shop = many hats.

Quote (spsalso)

I'm booked up for awhile, but it does sound interesting.

It's fun work and a lot of interesting things to learn about. Each unit gets refueled around every 18 months, usually in the spring or fall when power demands are low.

DC Cook has two units with four pump motors each that are on a ten year replacement schedule. We keep a spare motor in the plant in case it's needed for a total of nine motors. We replace one motor each outage with the spare and send the old one out to be rebuilt. When it comes back it goes on the spare motor stand until the next outage. When they have all been changed we get a couple outages that we don't need to do it but then it starts all over again.

There is a lot of other work that needs to get done at each outage. A lot of testing of systems that can't be tested when it's running. They test the thickness of steam generator and condenser tubes and other safety related systems. That sort of thing. Usually six twelve hour days for four or five weeks. Some plants use only union workers and some use non-union. There is a background check and psych evaluation. Nothing too hard to get through. Search the web for your nearest plant or do some traveling. I've worked at five different plants from Iowa to Pennsylvania.

Quote (zebraso)

They had 3 phase 240 (a+b) going in there from the same lines that fed the residential blocks and same sized center tap pole transformers as residential.

I got no idea what you are trying to describe but it could be 120/240 open delta. It only needs two transformers on the pole and can be up-rated by adding another transformer. The power company can usually supply whatever type of power system the customer asks for depending on their needs. Not all industrial customers have the same needs. I've worked in General Motors plants that have their own sub-stations and 13,800 volts running through the plant.

Nukeman948,

Interesting for sure! It's fun to hear about other people's work.

I assume that there is only bearing wear on a motor. I suppose other things could be checked, of course, like insulation resistance. I asked because I've assumed that big stationary motors under relatively smooth or continuous loads don't have bearing wear. Bearing lubrication and its pressure can be nicely controlled, I would think.


spsalso

Not that it matters. There were 3 transformers with three lines into the building. One transformer was doing duty simultaneously powering street lights with return to neutral. I'm pretty sure the transformers were in delta, which is where 240 comes in. When they tore down that building they left the transformer on the pole that was connected to the street lights, but removed the other two from the tri-mount. But I am sure all three fed the building.
I worked in a plant that had to test a switch tube that operated at 100kv at a pretty high current. I think that was used in a microwave grain dryer. Lot's of x-rays with that tube. There was a substation in that plant too. Luckily I did not have to work around that tube. That guy was pretty nervous most of the time.
IOW all 3 kv lines (ABC) transformed and feeding building. Nothing special other that they also took a 120 from one of the transformers.

Edit: so it was closed delta. I put out a lot of jibber jabber. The main thing I was coming to grips with is 208 comes from a Wye connected setup. I had no good reason to throw in the stuff about what is a standard delta 240.

Quote (spsalso)

I assume that there is only bearing wear on a motor.

LOL. 20 years ago I heard that nuclear power plants make a million dollars a day for each unit. It's probably more now. They really don't like down time not to mention the safety concern if one fails unexpectedly. One developed an oil leak a few years ago and they had to pump in many gallons of oil while it was running. There is no comparison between the complexity of these motors and the operating conditions they run in with the typical exhaust fan motor. They have air coolers to cool the air that cools the motor because of the ambient heat inside containment. The standby motor needs power continuously running through the windings to keep them warm to keep them from absorbing moisture out of the air. So yeah, every component that could possibly fail and result in down time gets checked over and replaced if it will keep the lights on. It is an interesting place.

Link

Quote (zebraso)

The main thing I was coming to grips with is 208 comes from a Wye connected setup.

Just to derail things even more, a 120/240 delta is also called a wild leg system and has 208 volts from the wild leg to the neutral. But they don't make any equipment that uses it so...
A 120/240 three phase panel that is only feeding single phase loads will have two breakers and a space, then two breakers and a space etc, because the space is the wild leg and is useless.

Google "mercury arc rectifier" and see if anything looks familiar.

Quote (Nukeman948 (Electrical))

good stuff

Thanks man, Getting derailed is how I make progress.

As far as the mercury arc thing. I think it was more akin to a lighthouse tube. I know there was a large metal cage with a bank of very large capacitors that no one went into and a guy from the utility once was killed in there when he fell off a platform. That's where they got the 100 kv from. You had the tube and the cage. I wish I knew more. I don't know if the switch tube was for turning on and off power to the microwave tube or developing 100KV DC via a doubler etc. They made Klystrons also. But they were only testing the switch tube in this spot beside the cage. It was surrounded by a very thick lead shield for testing. It could have been a rectifier that got you to 100 KV but there was no mercury in it that I heard of. I had to calibrate the meter that measure 100kv (by divider) once in the active system. Strict procedure and the product engineer was nervous just doing that. I never had to get a probe close to the 100 KV that I can recall. But I could be wrong. I don't think the rig I had went up that high. That was a prior life.
Something akin to this: look up S94000E Power Tube 120kv at 90 amps. So megawatt range I would say, anyway. Probably higher than that.

entertainment: Link

That should be right up nukeman alley. They were doing neutral beam stuff where I worked too. I know I said grain dryer, whatever.

From NBC: Surfside collapse exposes an overlooked threat: Saltwater rising from underground

Will be interesting when this Beast starts showing up on elevated parking decks at Florida Condo's.

"The all-electric monster pickup weighs 9,063 pounds and, according to new documents filed with the EPA, nearly a third of that is thanks to its battery."



https://www.foxnews.com/auto/the-electric-gmc-humm...

I think there is another mechanism that accelerates the salt based breakdown of concrete. Ironically it involves the ventilation fans. The salt attracts more moisture from the soil as the water evaporates. That in turn increases the salt concentration which increases the absorption of more water drawing in more salt ad infinitum at a rate that is increased by evaporation rate. One of the articles I read which I am trying to track down again claims a study show this process can draw water from the soil from as far away as 10s of miles depending on the conditions. That is not a simple problem and I don't see how it can be ignored.

Edit: this concept seems to go beyond the basic idea of "rising damp" where the water will permeate to a height were the evaporation rate equals the ingress rate. That is true with or without salt. What I think the above theory is saying is that as salt concentration in the concrete increases the rate water coming in will increase as a result. The mechanism for increasing the salt concentration is compounded by evaporation rate. I would like to see the study that shows that. Still looking.

While I am looking I thought this article on capillarity goes a long way. Link It's not about sulfate corrosion/erosion. But it addresses the forces of osmosis, which I think are the basis for the effect I am trying to describe. Interesting quote from article: "The theoretical limit of capillary rise in concrete is about 10 kilometers". Ouch.

It will be very interesting to examine the results of the concrete sampling done by NIST. We will be able to see gradients of ingredients and contaminants through the thickness in the basement walls and floors, as well as vertically, in the columns (using multiple sampling points).

We can then compare our theories with the facts.

It'll be fun!



spsalso

Quote (zebraso)

I think there is another mechanism that accelerates the salt based breakdown of concrete. Ironically it involves the ventilation fans. The salt attracts more moisture from the soil as the water evaporates. That in turn increases the salt concentration which increases the absorption of more water drawing in more salt ad infinitum at a rate that is increased by evaporation rate…….

Interesting thoughts, analysis and link. The ventilaton and circulation fan drying effects on underside of elevated parking/patio structural deck accelerates salt accumulation into lowest layer, in addition to gravity, then salt attracts moisture more.

Quote (thermopyle2.1 (Military))

fan drying effects on underside of elevated parking/patio structural deck

Thanks for adding that. There was a "but what about the pool deck" thought going on in my mind as well. But I thought I should focus on one concept at a time. I was following a thought process based on the article Maud posted for now. Please feel free to add any additional thoughts about the grade level drawing water based on the idea. The article I posted talks about damage going into wood flooring and members at or above grade level, but that's a different animal. The idea here was the membrane was supposed to do a certain amount of protection. But that seems to not have worked so well.

Quote (zebraso)

. I was following a thought process based on the article Maud posted for now. Please feel free to add any additional thoughts about the grade level drawing water based on the idea.

Sorry I jumped on the ceiling fan air flow drying train of thought on the ceiling of garage.

The fan drying the inside surface of garage walls, seems also to accelerate effects on walls too based upon your and Maud’s post, especially at upper portion of wall.

no need to apologize. You can jump to that. The sources I read talk about drying cycle, but not necessarily about continuous water supply and continuous drying. So I'm trying to figure out how it is different. The capillarity thing makes me wonder how failed the membrane actually had to be. We see photos of cores, but did we ever see a photo of the membrane exposed?

Quote (zebraso)

but did we ever see a photo of the membrane exposed

According to the Moribato report Link page S2A-1.1 the parking deck had no waterproofing.

Quote (MaudSTL)

Saltwater rising from underground

Thanks very much for sharing Maud. That ties in with the annular voids caused by sulfates, as mentioned in the article posted by dik, facilitating capillary action, and also from Link page 8 which states "Evans and Taylor also noted that sea salt particles cause corrosion at a lower RH [relative Humidity] than NaCl [Sodium Chloride] particles, due to the fact that sea salt contains very hygroscopic magnesium salts" attracting moisture.

Quote (spsalso)

Interesting for sure! It's fun to hear about other people's work.

Agreed, most of that is way out of my league, but I do know to keep my fingers at a safe distance when testing GM tubes powered from a 9V battery...

Quote (spsalso)

In THIS building, there are three hot wires and one neutral. Across any two hot wires is 208V single phase.

I'm glad you guys are familiar with three-phase systems because the associated vector math will come in useful when we get on to talking about vibrations.

Quote (IanCA (Mechanical))

the parking deck had no waterproofing.

It is interesting. The stampcrete fractures look pretty good. I hate to call that "curious", but.....

Quote (zebraso)

entertainment

Thanks for the entertainment. Out of my comfort bubble but thought provoking.

Quote (IanCA)

associated vector math

Sorry Victor, I don't do vectors. I got a phone app for that maths stuff.

Quote (zebraso)

It is interesting. The stampcrete fractures look pretty good. I hate to call that "curious", but.....

Quote (IanCA)

According to the Moribato report Link page S2A-1.1 the parking deck had no waterproofing.

I think the way the stampcrete has come up in sheets demonstrates how it was not bonded to structural deck below and trapping moisture between stampcrete and non waterproofed structural deck. I also feel the way some of the stampcrete is shifted at columns and the major concrete failure cracks in parking deck area near south wall and patio deck junctions, definitely point to the parking deck failure being due to chemical reactions in that area could be a huge factor in that area being initial failure point, near south wall. Couple that with construction vibrations next door, and cyclic loading of parking deck from auto movements and that area is a very stressed area.

I will be first to admit, my chemistry education ended as freshmeat in College, and had long been forgotten except for times where it affects everyday life like the voltaic cell battery in my autos. I remember as a kid my dad storing a 12V auto battery on a concrete pad outside our home and how it ate the paste in the concrete at a rapid rate and left honeycomb of aggregate and voids showing. From that time on, dad burned in my brain to put a wood board under auto battery to protect concrete. He was mechanical engineer so not chemistry major. Concrete patio was under a cover so not a lot of rain getting to it, but perhaps some in blowing rains.

Interesting short read on "Case Studies Show Galvanic CP Effective on Corroded Reinforced Concrete Structures". Interesting to note that repaired areas create a potential difference between old and new areas and basically cause the cancer to spread to new areas around repaired area. Here is quote below form short article:

"Chloride-induced corrosion of reinforcing steel in concrete is a major problem worldwide. Chlorides can be introduced into concrete through deicing chemicals, seawater, soil, or as contaminants in the concrete mix. This can lead to pitting corrosion and concrete deterioration."

"Localized repairs are often performed to address concrete corrosion damage. When a repair is completed, new corrosion sites can form just outside the repaired area and are driven by the residual chloride contamination and the difference in potential between the steel in the chloride- contaminated and chloride-free sections. When incipient anodes form, further repairs will be required. The patch repair process may be repeated several times over the remaining life of the structure."

https://blogs.ampp.org/case-studies-show-galvanic-...

Per the link below, it clearly appears we have sulphate attacks where concrete or layers of concrete turned into powered mass. As stated earlier only lab tests of many samples of concrete will conclusively determine if more than one chemical process was going on at the same time, perhaps in different locations or layers.

"Types of chemical attacks on concrete structures per link"

"Following are the different chemical actions on concrete structures
Sulphate attack
Chloride attack
Alkali aggregate reaction
Carbonation
Acid attack"

"Magnesium sulphate also reacts with hydrated calcium silicate and makes concrete into powdered mass." "Concrete with low water cement ratio is less affected by magnesium sulphate while high water cement ratio concrete is highly affected. Sulphate-resisting Portland cement should be used where sulphates are present in the soil, water or atmosphere and come into contact with the concrete."

https://theconstructor.org/concrete/chemical-attac...

Quote (thermopyle2.1 (Military)

trapping moisture between stampcrete and non waterproofed structural deck.

Substitute membrane for stampcrete now. It's unfortunate when water proofing ends up sealing in moisture. I requires a lot more thought then what often gets put into it. And these so-called repairs are merely superficial attempts at stop gaps. Good post there.

Edit: since you mentioned vibrations next door...what if that cracked the non-structure supporting deck just beyond the membrane and that became the primary entry point for water? just throwing spaghetti. Is this where we have to do vector math?

Quote (zebraso)

Edit: since you mentioned vibrations next door...what if that cracked the non-structure supporting deck just beyond the membrane and that became the primary entry point for water? just throwing spaghetti. Is this where we have to do vector math?

I am thinking the after construction aftermarket membrane stopped at pool deck side of planters between parking deck and pool deck. Planters create sag, so water is drained towards planters and ponds there making that already overloaded K-Line even more vulnerable with decaying reinforced concrete, probably construction joint in that area too. Then add vibrations to loosen things up even more, and Shazam!

How is that for some meatballs to go with your spaghetti? I assume vector math has to do with diagonal parking slab failure across a rebar grid, and motion vectors on columns from the vibrator next door?

Personally I am up for linear vector math, but not non-linear equations.

Quote (thermopyle2.1)

"Types of chemical attacks on concrete structures per link"

Another great document, thank you very much.

Quote (thermopyle2.1 (Military))

I assume vector math has to do with diagonal parking slab failure

I don't know. IanCa mentioned in reference to vibrations. One of the things that is missing in terms of another type of timeline is when and how severe the water entry was. Supposedly there was a mention by a worker that pumps were burning out running 24/7 to keep up. When was that? Were they pumping out a sump? When did it first become necessary to put up drip panels and where were they needed first? Who did it? were they approved by someone? Someone know these answers.

Edit: one might assume the pumping was from the drainage wells (not proper term), but would one king tide be accountable for burning out pumps? Too many questions. I can't imagine water from grade is what that was about. I mean at the point where Ostroff made the walk-through analysis I don't know if he was considering the drainage wells. But the question stands was that water on the floor of the garage or not. I still say there are people associated with the building that know these things. And I assume they have been questioned.

Quote (zebraso)

since you mentioned vibrations next door...what if that cracked the non-structure supporting deck just beyond the membrane and that became the primary entry point for water?

I think there is a chance that if the structural deck was already weakened it could crack, or the cracking could be accelerated, between the deck side of the planter and stampcrete. I expect the stress could be concentrated there, where the step changes in stiffness occur.

Quote (thermopyle2.1)

I assume vector math has to do with diagonal parking slab failure across a rebar grid, and motion vectors on columns from the vibrator next door?

I was thinking about the stated NV5 threshold of 0.5 inches per second, because if you have three measurements of say .558 longitudinal, .408 transverse, and .583 vertical, at close to the same frequency, I think you end up with a significantly higher resultant vector that's not aligned with any of the measurements axis. Is that right?

Quote (Nukeman948)

I got a phone app for that maths stuff.

Please can you check, assuming they are at the same frequency and in phase?

Ahem,

If the three components are aligned in phase and each is 1 unit, the resultant will be sq root (3) units, ie 1.732 units.

Quote (IanCA (Mechanical))

structural deck

Yes of course. Sorry. any distinction there that I may have been trying to insert does not have merit. And whatever I was trying to say should have been stated differently to convey what I meant. That way it could be determined if it had merit. There is no need to rehash that. I never had a bone about it.

@zebraso I hope my clarification didn't come across as a criticism. It wasn't intended as such. I was only attempting to clarify for others reading at a later date. I appreciate you confirming that we are on the same page.

Quote (IanCA (Mechanical))

I think you end up with a significantly higher resultant vector that's not aligned with any of the measurements axis. Is that right?

I don't have the answer, but I have another question. If these vibrations were felt throughout the structure, is it reasonable that they were not being damped? Are we talking about sheet pile still? Is that what they felt? Or was it impulse from an excavator banging around? Are you talking about reflections adding in a way that excites some local node. Is NV5 peak, rms, average? And is that the threshold for all damage? I should look it up.

Quote (zebraso)

Are we talking about sheet pile still?

I'm not sure about the damping. Yes, I was thinking about sheet pile installation. I'm pretty sure there is a large difference in the vertical stiffness between the wall and the deck. I can imagine the deck bouncing more or more likely to resonate. The figure of 0.5 inches per second came from the class action complaint and has no further detail from what I can see. I don't think the original documents have been released. Perhaps the 0.5 inches per second figure already includes an allowance for vibration on the other two axis, I don't know. I thought it was interesting that 100 linear feet of the sheet piles on the north of 87 Park were installed deeper. I'm assuming that was the portion adjacent to CTS (as opposed to the pool deck). I would be interested to know if anyone has more information about that aspect.

Quote (spsalso)

would those rotating charges affect wireless transmissions

I think you are right, almost certainly why we don't have 5G FR2 yet.

Quote (spsalso)

could perhaps a sudden solar eruption have triggered the fall of the building

Well, as you probably know, a solar flair did apparently contribute to the loss of 40 Starlink satellites launched Feb 3, due to increased drag, but they were a bit higher up. Link

Quote (AusTony2046)

the resultant will be sq root (3) units, ie 1.732 units.

Thanks for that, I should have thought about it a bit more. But I'm wondering whether the combined effect of the vibrations at three different frequencies on different axis is more or less likely to cause resonance or damage than vibration concentrated on a single axis. What do you think?

Quote (IanCA (Mechanical))

likely to cause resonance or damage

Once again I don't have the answer but I have a quote regarding the British standard or at least a subset of it:

For continuous vibrations, the British
standard states:
The guide values . . . relate predominately to
transient vibration which does not give rise
to resonance response in structures, and to
low-rise buildings. Where the dynamic loading caused by continuous vibration is such as
to give rise to dynamic magnification due to
resonance . . . then the guide values may need
to be reduced by up to 50%. Note: There are
insufficient cases where continuous vibration
has caused damage to buildings to substantiate
these guide values, but they are based on common practice.

Edit: I have to be careful not to be misleading. For the British standard this still put the threshold for continuous in the 30 hz range at around .8in/sec. BUT it is 1/2 of the USBMRI8507 for the same conditions (with nothing mentioned about resonance), This is different still from the Swiss standard which is about .3 in/sec for continuous at 30 hz for this type of building ("well designed and maintained"- love that). DIN would be .3 in/sec for transient at 30 hz at the base and even lower for continuous but that is at the top of the structure so it's not comparable. The only one that calls out resonance seems to be the British. Don't take my word for it
Link
While that is about historic building preservation it does a really good job of comparing standards, even superimposing them on each other.

Quote (IanCA (Mechanical))

if you have three measurements of say .558 longitudinal, .408 transverse, and .583 vertical,

I was looking at a study from Sweden trying to model vibration for sheet pile. They drove 7 piles monitoring 1,2, and 4 while they were all driven in interlocking succession. they have sensors top middle and toe. frequency is 35 hz. Anyway on the 4th pile measured on that pile the top sensor near the end of the drive was hitting around 40 g longitudinal. unless I am mistaken at 35 hz that is 70 ips peak. Is that sort of level going to be attenuated down to .5 in the distance we are talking about?

> if you have three measurements of say .558 longitudinal, .408 transverse, and .583 vertical, at close to the same frequency, I think you end up with a significantly higher resultant vector that's not aligned with any of the measurements axis

Yes - by nearly double in this case. But in the context of a slab or column with clearly defined primary axes, the primary stress axes (which is what you should be measuring) are likely to line up with the geometry. Perhaps this is not the case at the end of the slab where it meets the wall though.

The idea of airflow inside the garage drying the inside of the walls and encouraging salty water to migrate into and through the concrete by capillary action is an interesting one. Surely though if that was something that could happen on this kind of timescale, we'd know about it and there would be rules about waterproofing the outside of sub-grade concrete lined spaces, because otherwise this would apply to every building near the seaside with underground parking.

Quote (IanCA)

Please can you check, assuming they are at the same frequency and in phase?

Oh, certainly, I'll get right on that, Victor, err..vector. Unfortunately my batteries couldn't hold up to the strain but just before it died I was looking for an input value that corresponds to the third order harmonics of the pile driver and some kind of assurance that the frequency and amplitude would remain stable throughout the time period in question and also the modulus of elasticity of the soil type at the site of the alleged damage. I'm currently studying up on the works of the great mathamagician Paul Simon and his thesis: "There Must Be Fifty Ways To Shake Your Tower".

Quote (zebraso)

While that is about historic building preservation it does a really good job of comparing standards, even superimposing them on each other

I found that to be an interesting and helpful document, thank you. Here are the points that stood out for me:

Fig 2 put 30Hz at 0.5in/sec into the intolerable region.
Internally Amplified measurements can be 4 to 8 times higher than at the base of the building.
52,000 cycles at 30Hz is less than half an hour.
Strains in walls caused by thermal expansion are several times higher than those caused by vibration.
Key factors:
1 - Building type and condition
2 - Continuous vibration
3 - Importance

All structures should be evaluated on their own physical condition.
Applies limit reduction 50% for 1,000 to 100,000 cycles. Applicable to CTS and vibratory sheet pile driving.
60% above 100,000 cycles.

Resonance and preexisting weakness can be problematic.

Stipulation of protocols to be followed if recorded vibrations exceed the specified limits. Were any specified for CTS?
Post-construction condition surveys. Were any done?
Surveys should be repeated after any above-limit vibrations. Were any done?
Elevation surveying for settlement, crack-width measurements, and visual surveys of general building conditions.

Quote (Nukeman948)

Unfortunately my batteries couldn't hold up

I'm beginning to wonder whether that calculator of yours is real or imaginary. Don't worry AusTony2046 already came up with the answer to my specific question and Red Corona put things into context:

Quote (Red Corona)

But in the context of a slab or column with clearly defined primary axes, the primary stress axes (which is what you should be measuring) are likely to line up with the geometry.

I suspect the vertical component is the critical one.

The most important point for me is that if you pay an expert for professional advice on vibration monitoring, and they give you a limit not to exceed, and your on-site measurements, made in accordance with their recommendations show that you are exceeding that limit, then you need to take action to reduce the vibration or seek advice to understand why the data could be erroneous and you need to check whether there was any adverse effect on the structure.

Quote (Nukeman948)

What is the point of presenting facts and data when 30% of the population is convinced the earth is flat?

Taken with the appropriate quantity of NaCl. A pinch.
Because it's possible to gradually inform the skeptics, reducing that percentage, and everyone stands to benefit if we can come to an agreement.

Quote (IanCA)

I'm beginning to wonder whether that calculator of yours is real or imaginary.

My calculator is just another tool I use in exchange for proper compensation to support myself. I see no reason to allow it to be used by persons who wish to deny proper compensation to the real victims of this tragedy.

With a grain of salt...

Quote (IanCA)

The only difference between science and screwing around is writing it down.

You might want to rethink that Inspiring thought, as what came to my mind immediately was Jeffery Epstein?

EDIT: But my elevator does not go to top floor.......

Quote (Nukeman948)

I see no reason to allow it to be used by persons who wish to deny proper compensation to the real victims of this tragedy.

Personally, I am fully in favor of the real victims receiving proper compensation. As an engineer, I'm also committed to helping to improve our understanding of the risks involved so we can reduce the chances of events like the collapse of CTS happening again in the future.

Thanks for your advice thermopyle2.1.
Reposted with a clarified signature line.

Quote (IanCA)

Reposted with a clarified signature line.

I must not understand how signature lines work.
I thought I'd need your password to be able to insert my favorite Mythbusters quote in your signature line.

Quote (Nukeman948)

I thought I'd need your password to be able to insert my favorite Mythbusters quote in your signature line.

No need for all that credential nonsense, just make the substitution in your mind.

Quote (IanCA)

Suggestions welcome.

Suggestion: Just Following the Science!

Edit: I can see the vibration damage being a valid complaint against 87 Park, but I am having trouble with the water entry into the wall due to removal of 87 Terrace. The reason I am having a problem with water entry is that CTS was built all the way to the property line, with no provision to prevent water entry from property line side of wall. Anytime you build all the way to a property line, you are inviting trouble from your neighbor. You can not even paint your retaining wall without getting permission to be on the other person's property.

But then I have always thought Condo's and Townhouses were a stupid concept that can make life painful depending on who your neighbor is.....

"neighbor" used to be a street.

Right, and street was better neighbor as they sloped drainage away from wall rather than towards it.

On one hand 'neighbor' purposely drained towards wall, which is wrong, but when folks build up to line there is no room for U&D easement. And I agree neighbor's should NOT drain water on to their neighbor's

Again, building to line invites problems

Around here the streets are crowned and the water runs to the edge where it is contained by the curb and gutter and diverted to a catch basin or some other drainage method.

Quote (thermopyle2.1)

but I am having trouble with the water entry into the wall due to removal of 87 Terrace

I agree that building to the property line is problematic, particularly when the other side of the line is a different jurisdiction.

I concur with the valid points about the street / public right of way and the original drainage.

Is it possible that the removal of 87 Terrace also had some impact on the lateral stability of the CTS property line wall? With respect to thermal expansion of the parking deck & pool deck?

Quote (IanCA)

Is it possible that the removal of 87 Terrace also had some impact on the lateral stability of the CTS property line wall? With respect to thermal expansion of the parking deck & pool deck?

Interesting thought, as the concrete walk was poured up against wall. Not sure whether poured against concrete wall though. But definitely had a water change due to removal, and yes I guess road way and concrete curb and walk did provide lateral bracing to concrete wall, at least due to compaction of ground under street and walk.

Quote (thermopyle2.1 (Military))

Again, building to line invites problems

I concur. I was thinking "terrace" was the old Hotel that was torn down. So the removal.... well that's where I missed that it was the road you were talking about. So not just was the road removed as such but the land was repurposed with no apparent interest in what function it was providing to CTS before or whether it was access or whatever. It just had no priority.

Quote:

You can not even paint your retaining wall without getting permission to be on the other person's property.

That is a very interesting point. Does this explain why they did not even attempt to fix the water coming it, assuming they knew about it. If this was all understood as a fact before the collapse, why didn't they use the law to address it? This kind of crap is Judge Judy territory. Damage caused by action of neighbor? But because of politics maybe they couldn't? This part really seems to stink and suggest there is more going on that has been told. These are the questions that beggar the imagination. And I believe they are claiming this now as if it was a known fact then.

Edit I now see Morobito attributed about $80K in damage to the privacy wall to 87 Park construction. I don't know is this is just where they scraped it with an excavator or more than that. And he noted the drainage being funneled towards CTS - which is denied by the developers. So there is the pissing match.

I don't know anything about the property laws in Florida but my property line is actually the center of the street and the city has an easement for the street and all the utilities that pass my house. I can landscape right up to the edge of the street as long as it doesn't create a safety hazard for motorists but they won't replace my daisies if they need to dig up the water line.

If CTS's real property line was the center of the street it may explain why 87 Park wasn't able to build right up against CTS's sheet piles and why they were required to rebuild a public sidewalk access to the beach on the old easement.
So did only one city own and maintain this street or did they share that? Were both cities required to sign off on the sale of the street? Is the city responsible for the water problems caused by it's sidewalk? Seems like some real murky legal issues need to be resolved before the other blame games can continue.

I know CTS had THEIR city building inspector come around, who essentially said "It's not my jurisdiction." He MAY have been otherwise unhelpful. Or he may have suggested other routes to ease their concern.

Did anyone at CTS think it appropriate to get an engineer's opinion on problems they could encounter with the neighboring construction?

If so, what did that engineer say?

If not, why not? Was it considered not important enough?



spsalso

Kilsheimer resets expectations as the state legislature considers updated inspection and certification requirements. Investigator hired by town expected to release findings by June 24: Findings delayed in Surfside condo collapse

Quote (Nukeman948)

If CTS's real property line was the center of the street

Understood. I just checked it is at the CTS southern wall.

Quote (IanCA)

I just checked it is at the CTS southern wall.

Is there any chance you could check to see who owns that public sidewalk?

8701 Collins

From Miami Dade GIS Maps

https://gisweb.miamidade.gov/eMaps/

Here is legal description on 8701 COLLINS AVE CONDO. Looks like 6 lots, part of erosion way and adjustments to Blocks 1 and 10, plus 50 ft road closed. Would need to look at plat books, and deeds cited below to see full details. But it appears City Sold Right of Way of Road from this. Perhaps public access is an easement on property?

ALTOS DEL MAR NO 2 PB 4-162
LOTS 1 THRU 3 INC BLK 1 & LOTS 1
THRU 3 BLK INC BLK 10 & PORT OF
EROSION WAY LYG BETW & ADJ TO
BLKS 1 & 10 PER PB 105-62
& 50FT RD LYG N & ADJ CLOSED
PER RES #2014-28608 & 2014-28839
AS DESC IN DECL 31691-1664
LOT SIZE 101179 SQ FT

Is the West edge of that property shown in the aerial photo actually running down the center of the sidewalk? So does that mean it has been confirmed that the property line is not the center of the street?
Is that considered good enough for legal work in Florida?
Were all the laws adhered to in the sale of a city street to a private entity?
I seem to remember some of those issues haven't been fully explored in court yet.

Skeptical, The aerial photo looks like property line is running along North edge of sidewalk to me. If you click link and go to their GIS map site, you get a lot better image than that to look at.

In my state, property lines are typically not the center of streets. In plat mapped residential sub-divisions the street Right of Way is say 50 feet wide, but road is only perhaps 30-35 feet curb to curb. The other 15-20 feet are divided evenly on each side of road and are basically used for utilities. So property lines for lots are typically not at curb of street but 7-10 feet past curbs. So you end up maintaining part of the right of way for the city.

Definitely some shady dealings went down, and I expect it to be interesting legal battle.

Quote (thermopyle2.1)

The aerial photo looks like property line is running along North edge of sidewalk to me.

No. I was talking about the WEST edge that runs along Collins Ave. But then your other image shows the property crossing the city limits into Surfside on the North. Not sure how that works. Really doesn't matter, it's not going to get resolved here.

I know if I don't mow that 15-20 feet of lawn along the street, the city will come do it for me and send me a bill.

Quote (Skeptic Al.)

I know if I don't mow that 15-20 feet of lawn along the street, the city will come do it for me and send me a bill.

I assume the city just has easement on your property, thus you are still the owner and have to cut the grass? I know here, if the lot is vacant, and a complaint is filed the City will cut the right of way grass in front of vacant lot and not charge the land owner, since the land belongs to City. But I do not know what would happen if I quit maintaining the ROW in front of my house for the City. Perhaps they would come cut it too as it is their land, but I am not aware of anyone who has tried not cutting the ROW on a developed lot.

My guess is City would cut it on developed lots too, but it would NOT endear the land owner with the Power Brokers at City Hall?

@Thermopyle2.1, thanks for finding and sharing that information. I like it.

I started from here: Link, zoomed-in and clicked on the location. But it's not as user-friendly.

The GIS version you shared has more features and information, but the land use data is different. It still shows 87 Terrace as a road.

Quote (Thermopyle2.1)

But it appears City Sold Right of Way of Road from this.

The story I heard was that sale of public roads was not permitted so it was given in exchange for a cash donation.

Quote (Nukeman948)

Is the West edge of that property shown in the aerial photo actually running down the center of the sidewalk?

Looking at Google street view. The width of the sidewalk was approximately doubled when 87 Park was built. The property line aligns closely with the original sidewalk.

Quote (Nukeman948)

So does that mean it has been confirmed that the property line is not the center of the street?
Is that considered good enough for legal work in Florida?

As an engineer. Did you know it was engineers week? I would say that the data available in the public copy of the official record indicates that the beach access path entirely crosses the property referenced by Folio: 02-3202-165-0001, which is abutted immediately to the north by the property previously occupied by CTS and referenced by Folio: 14-2235-025-0001. As such, as far as public records show, there is currently no publicly held land located between Folio: 02-3202-165-0001 and Folio: 14-2235-025-0001.

Quote (Nukeman948)

Were all the laws adhered to in the sale of a city street to a private entity?
I seem to remember some of those issues haven't been fully explored in court yet.

Good question. I completely agree.

Quote (Nukeman948)

If CTS's real property line was the center of the street it may explain why 87 Park wasn't able to build right up against CTS's sheet piles and why they were required to rebuild a public sidewalk access to the beach on the old easement.

I suspect the Miami Beach council was simply under pressure to maintain public beach access, but from what I can see, they still transferred the entire piece of land previously occupied by 87 Terrace to the owners/developers of 87 Park.

Quote (IanCA)

As an engineer. Did you know it was engineers week?

Yes, it seems everyone has a manufactured holiday based on their job title to make them feel good about themselves and forget they are nothing more than a cog in someone else's money machine. When the cogs are worn and out of spec they get tossed in the scrap bin with all the rest of the used up dregs of the world.

There is no children's day because every day is a holiday for children. There is no holiday for retiree's for the same reason. Cogs that are not yet useful and cogs that are no longer useful. And the useful cogs and the machine owners have no use for either one.

If you build your own money machine you will find an ample supply of cogs looking for a place to fit in. If you work the machine too hard, some cogs will break from the stress and some will be ground to a fine powder. But churning out money is the only freedom that they know. Slaves to someone else's empire of greed.

And yet we keep building larger and larger machines. Soon we find Cogswell Cogs and Spacely Sprockets are competing with each other to have the largest money machine ever imagined. Rakes and shovels and implements of destruction to scoop all that money into the largest pile of money that man has ever known.

I have no idea where I was going with this and no idea why you thought a made up holiday was relevant.

Welcome my son. Welcome to the machine.

Is this question rhetorical too?

Quote (Nukeman948)

For longer life, keep your backlash within spec.

Is this creative writing or has a Sparky set up ring and pinion gears in a differential?

What I would like to see if the complete deeds and plat maps posted on line from before current 8701 Collins owner purchased property and tore down existing building, coupled with before and after ROW transfer from City to current 8701 Collins owner, and today's plat maps and deeds.

In my County and City all this information has been digitized and these public records can be accessed on line, rather than the old method of going to county record room to manually research deeds, mortgages, plat map, etc. records. At least ours are digitized back to around 1990 time frame. Beyond that manual look up still required.

I could not find access to actual deeds and plat maps for Miami-Dade on line, where we could see complete legal descriptions of parcel's of land and how title was transferred on these properties over time.

Perhaps someone 'Dangerous' in the South Flordia area has access and would be willing to post this information???

These are public records, and yes you may have to visit the real estate property room to copy the information, if there is not an online digital access in Miami-Dade?

From the Miami Herald: Engineer, law firm agree to settlements in Surfside collapse lawsuit. Terms undisclosed

Quote (Nukeman948)

nothing more than a cog in someone else's money machine,

Perhaps that's why I feel it important to be here.

Quote (Nukeman948)

no idea why you thought a made up holiday was relevant

Maybe I was just testing to see if you were an engineer or a philosopher or both.
Not relevant to this collection of threads, but to the site in general?

Thank you for your profound and thought-provoking response. I tend to agree.

Quote (thermopyle2.1)

What I would like to see if the complete deeds and plat maps posted on line from before current 8701 Collins owner purchased property

Agreed, that would be very helpful. Let's hope something turns up.

I will soon get back to clarifying the possible sequence of events as I see them with a diagram and some more information. This weekend I hope.

Quote (IanCA)

Maybe I was just testing to see if you were an engineer or a philosopher or both.
Not relevant to this collection of threads, but to the site in general?

WOW, I seem to have my very own groupies. Strange days indeed. Most peculiar even.

Maybe I'm not an engineer.
Maybe I'm not a philosopher.
Maybe I'm not some random idiot on the internets.

Quote (thermopyle2.1)

Is this creative writing or has a Sparky set up ring and pinion gears in a differential?

Like you, I have received training in multiple disciplines. Master of none as they say. But don't sell me short.
When a person is not obsessed with money they are free to pursue whatever their heart desires.
But with some people it's "All About Money". AmIright?

Quote (Nukeman948)

Like you, I have received training in multiple disciplines. Master of none as they say. But don't sell me short.

Trust me, I would never sell you short based upon your post showing an obvious broad background! I was impressed with your Jetson enhanced post and how you knew about gear backlash!

It brought by memories from childhood cartoons coupled with auto rebuilds that most have never even thought about!

You earned another Star!

BTW, I did not know answer to your West sidewalk question, however it could be 87 Park just wanted wider sidewalk in front of their Spaceship 🚀?

Finally, Netflix has a documentary film, ‘Downfall’ explaining how ‘All About Money’ culture change was behind 737 Max MCAS criminal coverup and failure by Boeing, after McDonnell CEO took over joint company. It shows how good engineering culture gets replaced with short term Stock Price focus.

Quote (IanCA)

I will soon get back to clarifying the possible sequence of events as I see them with a diagram and some more information. This weekend I hope

I look forward to reading your full sequence post.

Thermo, If I recall correctly, that sidewalk should be property of Miami-Dade Public Works.

Precision guess work based on information provided by those of questionable knowledge

Demented, thanks for your response. I think what Nukeman was asking was why side walk was widen on East side of 8701 Collins Property line as shown on GIS maps I posted. Clearly anything west of their property line is Street ROW. In my state, there are no utility easements at street on my property, only on sides and back for U&D. At street ROW stops at property line.

Edit: Perhaps Nukeman will confirm if I understood his question correctly.

Edit 2: I must say I am impressed that you got 2 Stars for answering the question incorrectly! That is impressive.....

I was just a little late on replying to something, I think. Shutdown is coming up, oh joy. Days have blurred into weeks.
It's an easement for that vacant lot owned by the Public works that is essentially public beach access. The town sold off the road only, but not the easement or beach access lot. 87 park developers would more than likely have "permission" of some sorts from Miami-Dade to renovate their property so long as it all fell in line with code and permits.
Folio 02-3202-006-0670

Maybe it was nukeman who asked. *shrugs*

Anyway, yeah, sidewalk is owned by Miami-Dade Public Works.


Edit: If gold stars in Kindergarten were this easy to get, I might have gotten somewhere in school.

Quote (Demented)

The town sold off the road only, but not the easement or beach access lot.

Thank you.
The public beach access, who owns it and who is responsible for it, was the point I was trying to get clarified. I only mentioned the Collins Ave. sidewalk to point out that the information, as presented, did not seem likely to be accurate.

Miami Dade GIS Maps disclaimer:
Miami-Dade County provides this website as a public service to its residents and visitors. The County is continually editing and updating GIS data to improve positional accuracy and information. No warranties, expressed or implied, are provided for the positional or thematic accuracy of the data herein, its use, or its interpretation. Although it is periodically updated, this information may not reflect the data currently on file at Miami-Dade County and the County assumes no liability either for any errors, omissions, or inaccuracies in the information provided regardless of the cause of such or for any decision made, action taken, or action not taken by the user in reliance upon any information provided herein.


Trick question of the day: How many links does a chain have?

Quote (demented)

Anyway, yeah, sidewalk is owned by Miami-Dade Public Works.

Demented, Municipalities don't own easements. Easements are NOT ownership in land, but right to use that part of someone else's land. Right of Ways are owned by Municipalities. It appears that West of property line has to be ROW, and East of property line on Collins has to be easement if city is using for utilities and such.

Edit: Or as Nukeman now is saying, the data base is CRAP!

Edit: Nukeman's original cryptic question was concerning only sidewalk along Collins avenue in the question I was referring too. I was NOT talking about Beach Access.

This is a prime example of why this forum is a waste of time for all of us, on this kind of stuff. It is like texting vs talking to someone directly, in that a lot of context is lost.......

PS: Whoever gave you the 2 Stars reminds me of the old saying, "Ignorance is Bliss"......

Quote (thermopyle2.1)

I look forward to reading your full sequence post.

Here is a diagram indicating what I believe to the approximate sequence in which elements of the parking deck, pool deck and building support columns failed.



The positions of most of the cracks in zone one are taken directly from photographic evidence, but some are inferred.

With reference to MaudSTL's timeline summary posted on 3 Feb 22 17:50.

I believe the failure of zone one occurred relatively slowly and agrees with timeline item 2 (banging heard from 11PM onwards increasing in intensity) until the southern extremity of the deck detached from the wall. That could coincide with the loud crash described in timeline item 3. I believe that area of concrete was very degraded and could explain the dust.

I believe the collapse of zone two occurred fairly rapidly due to the forces involved as an increasingly larger area of the deck begins to fall. This could likely coincide with the very large crash described in timeline item 5. I have added a letter suffix to indicate the relative time of the collapse. The progression is generally from south to north but the collapse of the eastern region is delayed slightly until it finally reaches the wall at 2E.

I'm interested to hear comments. I can explain the sequence in more detail and I still need to explain why some areas of the structure are exposed to more salt than others.

Quote (IanCA)

Suggestions welcome.

Good start on graphic depiction. I would suggest adding column labels from original CTS drawings to make discussions of a particular column easy to reference. Perhaps add legend with timeline events to label those on drawing as well. One graphic could tell a lot of story.

I am interested in complete decay theory in Zone 1 causing loss of steel grid or concrete deterioration in that area.

Also interested in your vibration resonances leading up to further delamination and punch shear readiness.

More description of what is happening on time clock at each column or area would also be inciteful.

It is impossible to have an honest discussion with a dishonest person.

I made a small change to my name as a joke and changed it back.

When I used one of Thermopile's aka thermopyle2.1, and Thermobaric's aliases "All About Money" he feigned ignorance.

He created a new account with his old screen name after abandoning his old account under the alias "gonefishing2".

What is he trying to hide with multiple accounts and constant name changes?

I'm not sure what his motives are and I have no reason to accept any explanation he may offer. The same goes for his two friends.

Quote (Nukedude948 or Nukeman948 or whatever your current display name is)

It is impossible to have an honest discussion with a dishonest person.

When I used one of Thermopile's aliases "All About Money" he feigned ignorance.

He created a new account with his old screen name after abandoning his old account under the alias "gonefishing2".

I'm not sure what his motives are and I have no reason to accept any explanation he may offer. The same goes for his two friends.

So I assist in answering your question with true facts, and because you don't like the answer you attack me, and make false accusations rather than simply googling definition's of ROW's and Easements to confirm that what I said is the legal definition of those terms, and you don't even mention your question about property line on West side splitting new wider sidewalk.

Fine, I was done anyways because of the agenda's of some of the folks like Nukeman948 that add no value....

To my apparent two friends, as per Nuke's False Accusations, whoever they may be, I wish you luck if you choose to continue on.......

@thermopyle2.1 Let's keep going.

Quote (thermopyle2.1)

I would suggest adding column labels from original CTS drawings to make discussions of a particular column easy to reference.

Quote (thermopyle2.1)

Perhaps add legend with timeline events to label those on drawing as well.

Timeline by MaudSTL.

Quote (IanCA)

@thermopyle2.1 Let's keep going.

I would like to see construction joints noted in different color on your graphic, perhaps a dashed yellow line? The one on East is not shown, however it appears the white straight lines that cross at K15 are construction joints?

I have a hard time following flow of progression from 2A. I would like to see notations beyond 1,2,3 A,B,C,D like .column labels thru .column whatever extensions showing progression flow at each involved column. I clearly see spread for example from 1 to 2A, but as to why different pieces fall in sequence beyond that, it is nor clear. I think it takes narrative to go with picture and perhaps photo thumbnails referenced to logic to tell story.

Good work and I hope you continue with your attempt at explaining the puzzle.

Quote (thermobaric)

I would like to see construction joints noted in different color on your graphic, perhaps a dashed yellow line?

Agreed, that would be a good addition, but I'm not sure about the locations of some of those construction joints. Do you know if there is a drawing anywhere showing them, please?

Yes, the narrative is important but it will take me some more time to put it together.

Quote (IanCA)

Do you know if there is a drawing anywhere showing them, please?

All I have seen is the construction 🚧 joint section view in the original drawings. I have not noticed locations of joints identified.

Building Intergity's Latest Video talking about Proposed Florida Condo Law Changes

https://www.youtube.com/watch?v=HsUVT5nv2YA

Quote (Nukeman948 (Electrical)27 Feb 22 14:51)

It is impossible to have an honest discussion with a dishonest person.

I made a small change to my name as a joke and changed it back.

When I used one of Thermopile's aka thermopyle2.1, and Thermobaric's aliases "All About Money" he feigned ignorance.

He created a new account with his old screen name after abandoning his old account under the alias "gonefishing2".

What is he trying to hide with multiple accounts and constant name changes?

I'm not sure what his motives are and I have no reason to accept any explanation he may offer. The same goes for his two friends.

Nukeman948/Nukedude948's “RULES FOR THEE BUT NOT FOR ME” MINDSET

I guess one could ask why does NukeDUDE948/NukeMAN948 use a unique signature block on all his posts, but then I just consider the source and the answer is clear..........

From Mr. Porter's video, the proposed "initial" inspections (as required by potential new law, discussed) could be carried out by an architect. I wonder how Friedman would have approached this task if called upon to review CTS.


spsalso

Quote (spsalso (Electrical))

From Mr. Porter's video, the proposed "initial" inspections (as required by potential new law, discussed) could be carried out by an architect. I wonder how Friedman would have approached this task if called upon to review CTS.

As far as design architects or even design engineers, Josh Porter, made it clear a pure designer is not qualified nor has the right experience and skill set to perform Milestone Structural Inspections and design Structural repairs. He even went on to say he specializes in the inspection and repair side, and does not feel qualified to design say a new 10 story building.

His point being, Milestone Structural inspections needs to be performed by a qualified engineer specialist, not a pure designer, and conversely.

From Florida Senate bill 1702:

(starting at line 195) "For phase one of the milestone inspection, a licensed architect or engineer authorized to practice in this state shall perform a visual examination...and provide a qualitative assessment of the structural conditions of the building"

(line 205) "If the architect or engineer finds no signs of structural distress...phase two of the inspection...is not required."

Mr. Friedman was an architect. He would have been permitted to do phase one of the milestone inspection of CTS. If he found no problems, there would be no need for a more in depth phase two. Since he was probably more familiar with the building than any other architect, it would make sense to choose him to do the job.

For that matter, it looks like Breiterman would also have been "on the list". Another good choice, since Surfside approved of him inspecting his own work, rather than finding someone else.

And we know how good a job Friedman and Breiterman did. I'm sure they would have kept on doing following work to that same standard.


spsalso

Quote (IanCA)

1=Banging from 11 PM…

I just wanted to clarify that 11 PM is the earliest report of banging that we currently have, because that’s what time Chani Nir got home to 111. The banging may have begun before that time, but we have no statement to confirm what time it started. We don’t know, for example, what time Security Guard Shamoka Furman came on duty in the lobby, nor do we know if she was able to hear the banging too. If she was able to hear the banging, it might help us to know what time she began to hear it. If she heard it during her entire shift, then we ought to find out if the guard on duty in the previous shift also heard the banging, and, if so, what time they started hearing it,

I am scheduled to meet this coming week with Dr. Ganapati of FIU, who has joined the NIST team to work with witnesses, among other things. I will do my best to bring to her attention questions like these that would be helpful to get answered.

>>>>>Edit. I think another detail that would be good to know is which space the Vazquezes parked in. They arrived right after the loud crash at 1:10, and it would be good to know their likely line of sight as they walked to the elevator lobby.

Quote (MaudSTL)

The banging may have begun before that time, but we have no statement to confirm what time it started.

Understood, thanks for clarifying.

Quote (MaudSTL)

I am scheduled to meet this coming week with Dr. Ganapati of FIU, who has joined the NIST team to work with witnesses

Thanks for letting us know. I wish you the best for your meeting.

I'm still trying to find time to work on the collapse sequence narrative and joint details.

Please also ask Dr. Ganapati how the inept rebar provision in Member 11 of the failed bridge was missed.

https://www.nist.gov/news-events/news/2022/03/cham...

Quote (Thermobaric)

https://www.nist.gov/news-events/news/2022/03/cham...

I uploaded the link to the Witness Statement Timeline to NIST on their data portal back on 8/19/2021.

If the active sub-team working out a collapse theory right now feels confident in their theory, it would make sense to share it with NIST, even if you want to use screen names for professional reasons.

Becker, a law firm that represented the building’s condo association, said it would pay $31 million; Morabito Consultants, an engineering firm hired to inspect the building for its 40-year recertification process, said it would pay $16 million; and DeSimone Consulting Engineers, a structural engineering firm for another building nearby, said it would pay $8.55 million under the deal. Sale of the property will also be divided.

Quote (IanCA)

I'm still trying to find time to work on the collapse sequence narrative and joint details.

In case it would help, here’s how the Miami Herald infographic House of Cards depicts the construction joints. Dr. Lehman would have reviewed this prior to publication, so it may have been acceptable to her from an engineering perspective.

Quote (MaudSTL)

I just wanted to clarify that 11 PM is the earliest report of banging that we currently have, because that’s what time Chani Nir got home to 111. The banging may have begun before that time, but we have no statement to confirm what time it started. We don’t know, for example, what time Security Guard Shamoka Furman came on duty in the lobby, nor do we know if she was able to hear the banging too. If she was able to hear the banging, it might help us to know what time she began to hear it. If she heard it during her entire shift, then we ought to find out if the guard on duty in the previous shift also heard the banging, and, if so, what time they started hearing it,

I am scheduled to meet this coming week with Dr. Ganapati of FIU, who has joined the NIST team to work with witnesses, among other things. I will do my best to bring to her attention questions like these that would be helpful to get answered.

>>>>>Edit. I think another detail that would be good to know is which space the Vazquezes parked in. They arrived right after the loud crash at 1:10, and it would be good to know their likely line of sight as they walked to the elevator lobby.

We all have a few questions for the suitcase lady from the Justin Willis story if she is ever found. What made her think the building could collapse at any moment?

I am also interested in how long the deck collapse lasted. Witness statements make it hard to tell if it was a single boom or it was a series of loud bangs and rumbling over 5-10 seconds, which would be my guess.

At the risk of being repetitive, here are the two Miami Herald article links:

1. Original story, headlined "The Herald built a computer model to explore how Surfside tower fell. Here’s what it showed" By Dawn E. Lehman and Sarah Blaskey Updated January 12, 2022 4:45 PM -- per Dawn Lehman, "... describes the timeline of the collapse that we used to support the modeling we did."

2. The follow up story, headlined "The last stand of Champlain Towers South. Computer model, witnesses reconstruct the tragedy" By Sarah Blaskey Updated January 21, 2022 2:31 PM -- per Dawn Lehman, "... the modeling approach and different scenarios that we evaluated."

Quote (MaudSTL)

In case it would help, here’s how the Miami Herald infographic House of Cards depicts the construction joints.

Thanks MaudSTL, you prompted me to make another effort.

I think the Miami Herald infographic is slightly off because it appears to show the joint to the West as a straight line, but I think it actually steps about 2' - 3' further to the West, in the area south of column row 14 (South of the lobby area). This is based on photos that show the joint in the stamp-create aligned with the East face of the columns in row I as shown below:


But the joint in the structural deck appears to be further West than the West face of the columns in row I as shown below:


In order to predict where the joints were in the parking deck and pool deck I looked at the joint spacing in the garage floor slab, because the actual as-built positions can still be observed.

If the garage floor slab joints are overlaid on a drawing of the parking/pool deck they appear as shown below (with parking garage column positions emphasized):



The spacing of those joints can be aligned with features on the parking deck by mirroring the joints and shifting West as shown below:
New version showing regions, due to uncertainty.



The point I am trying to establish is the probability that there was an intermediate construction joint beneath the planter running South to North close to columns on line K, in addition to the two shown on the Miami Herald House of cards infographic.

Quote (Reverse_Bias)

I am also interested in how long the deck collapse lasted. Witness statements make it hard to tell if it was a single boom or it was a series of loud bangs and rumbling over 5-10 seconds, which would be my guess.

All the witness statements I have ever read (Nirs, Furman, and Vasquezes) are clear about hearing the deck collapse as a single, very loud crash rather than a sequence of bangs and rumbling over time. The MH calls it “one loud cascade of concrete” in the article explaining the House of Cards infographic.

Quote (Sym P. le)

…here are the two Miami Herald article links…

I think we still have to take the MH timeline with a grain of salt, at least until they reveal the witness statements they used as the basis for their timeline.

There are three areas where the MH timeline is at odds with contemporaneous, publicly available witness statements made in the days immediately following the CTS collapse.

The MH claims that banging was heard starting around 1 AM, yet Chani Nir stated at the time that she could hear banging when she got home to 111 at ~11 PM.

Sara Nir, who clearly and repeatedly stated at the time that the “first collapse” (that she thought was a wall collapsing above 111) occurred at 1:10 AM. Yet the MH states that crash occurred at 1:14, which is the time that Sara said she went to the lobby. This means there was a five minute interval between the “first collapse” at 1:10 AM and the deck collapse, which was the “second collapse” at ~1:15 AM.

The MH also claims that witnesses were able to describe the area of the deck collapse. In this article the MH states,”Witnesses described the collapsed region as initiating from the southern perimeter wall and extending to the northern edge of the pool deck, where a video shows the debris from the deck collapse at Column Line 9.1 near the southern edge of the 12-story tower. (That portion of the building was covered with debris after the tower fell and therefore the exact boundary is unknown.)”, which is not accurate. There is not one publicly available witness statement identifying the extent of the deck collapse. Sara Nir, Gabe Nir, and Nico Vazquez only saw the deck collapse after the fact, from the lobby and the porte cochere. The late Cassondra Stratton only saw the deck collapse after the fact from 410, having been awakened by the building shaking. Mike Stratton says she told him she could see the pool (meaning pool deck) had fallen into a sinkhole. Floridians seem to use the words “pool,” “pool deck,” and “parking deck” interchangeably, so the witness statements can be confusing, especially when you take into account that many witnesses are speaking English as a second language.

I updated the image in my 12 Mar 22 10:19 post above to regions for possible joints rather than specific locations.

Quote (MaudSTL (Computer)12 Mar 22 15:23)

A grain of salt or with a liberal dose? I see now that their modeling assumes the slab abutting the south perimeter wall rather than resting upon it. Of course, if that were the case, a catastrophy would be in the making if the connecting rebar corroded. I just can't see this as supported by the photographic evidence nor with standard construction practices.

The media industry pumps out content because that's what it does but I'm dismayed with the lack of quality found in too much of it.

This has nothing to do with engineering, but it is worth knowing that Miami-Dade has succeeded in maintaining its long reputation for corruption. 23 hours of first responder audio from two channels have been deleted, and the County failed multiple times to inform FOIA requesters of the deletion. The deletion includes audio related to the failed attempt to rescue the late Valeria Barth of 204, who died in the garage fire. From USA Today, Miami-Dade deleted critical audio files from Surfside collapse search-and-rescue effort.

Quote (Sym P. le)

The media industry pumps out content because that's what it does but I'm dismayed with the lack of quality found in too much of it.

As far as the Timeline: CTS Collapse Witness Statement is concerned, I get frustrated that the media creates flawed narratives that become accepted as factual. People go through the NYT and MH infographics and think they are looking at proven facts, when what they are really looking at is a combination of fact, fiction, and conjecture.

I visited the Champlain towers condo collapse site on Saturday and shot extensive amounts of video and photographs and as I had mentioned on one of my videos back in February about how they added some shoring poles to the Champlain towers north building in the garage and some unit owners closets, now they have added shoring poles on the patios of several units on the building here are some photographs I took on Saturday.

Quote (Jeff Ostroff (Electrical))

shoring poles to the Champlain towers north building in the garage and some unit owners closets, now they have added shoring poles on the patios

This does not inspire much confidence. Those poles are not there to support the balconies IMO. I bet they finally got around to testing the concrete used throughout. This should be a big deal.

At this point, these units must be impossible to sell, but the land value is approx. $1 million per unit (Based on $120 million offer for south towers property and 111 units).

When they did core testing, I am pretty sure it was done in unit 612. I was able to get inside that building 6 months ago, checking interiors of several floors, and saw that 612 had signs on its doors for construction crews, and instructions, etc. I assumed this must have been the unit, as they showed it on the news when he first arrived last summer and took core samples.

What I picked up on when Jeff posted the first photos of the shoring poles in the garage, is that most of them were under the Generator Room, which is right above the parking ramp. I was surprised there wasn't more discussion on that.

When this collapse occurred everyone said the building "pancaked", although it did collapse straight down for the most part...watching the video and rescue operations, it looked more like the floors just turned to sand, the balconies and columns were the only large chunks/slabs being retrieved by the cranes.
There has to be a problem with the concrete.

Yes, Sym I would be wanting out and selling at a loss to get out of that building.

Quote (Jeff Ostroff (Electrical)21 Mar 22 14:10)

now they have added shoring poles on the patios of several units on the building here are some photographs I took on Saturday.

After watching Jeff Ostroff's video on shoring poles on the balconies, I noticed they did NOT shore all the way to the ground. This appears to imply that the shoring is just a safety factor while they work on repairing the area above the shoring. I counted 4 floors of shoring and it would appear that implies a balcony slab repair and not column repair.

Great observation on that 1st floor not having shoring poles as well there, Thermobaric. Others have commented the same on my video. If you remember, on the 2nd floor of this floorplan there are a ton of extra beams on the 2nd floor to support the large shear wall likely, and this along with 2" columns is why this part of the building on CTS survived the initial collapse. So they likely felt there was no need to go to the first floor, although I think it would be prudent to add them there as extra insurance and to put people's minds at ease.

Great point on the beams under second floor, Jeff. Looking closer at the photo's posted above, I see the shoring aligns with a column line from the beam under the second floor to foundation. If that is a transfer beam, then it might appear they were supporting mid span deflection of floor slabs above transfer beam, at the exterior block wall that was not supposed to be load bearing?

I think their whole strategy here is preventing punching shear, and they are probably not so much worried about deflection. Well, one thing to keep in mind is that columns along the end of a building can only support half of a load of columns that are in the middle of the building because they have no other connection to a floor slab that continues onward, in other words, there are no tributaries outside the building only inside the building. likewise, columns on the corner of the building can only support about 1/4 of a load of a column that is in the middle of the building.

Jeff, agree less axial load on exterior column than interior column, when both just supporting slab loads. However, exterior columns have to resist lateral detachment of slab at column/slab joint or asymmetrical loading of columns. In the collapse it appeared exterior columns lost lateral floor bracing, due to poor floor attachment to columns. Now if that is transfer beam, that would imply column line above second floor beam is not axially inline with first floor column? I have not looked at North floor plans to determine which.

On page 163 out of 336 of the 1979 floor plan, you will see how the Champlain Towers North floor plan is almost the same as the South floor plan. You will see the gigantic beams all over the place on the left side of the drawing and of course, there are 24-inch columns in the garage to support all of this, and then from the second floor up to the 6th floor, you have 16-inch columns.

So clearly this part of the building is much more robust than the part that collapsed, which has me questioning, even more, why did they need to put the shoring poles there.

So this points more in the direction of they think there are shearing forces along the outside of that wall even though the columns are 16 inches, and they are taking steps to prevent the shearing along that wall, where the patio slab meets the wall at the start of the cantilever.

It seems they suspect weakness at that connection, maybe from lack of adequate rebar there.

Since you verified column line above beam is same as below, I would expect column or connection repair and they transferring slab load normally on column to lower floors then to column.

Just look at my 3rd picture of the photos I posted above, you can see the huge beam under the second floor, so no reason to add more shoring poles under the 2nd floor

Thanks Jeff for keeping us appraised of what's going on down there. Sunlight is the best disinfectant.

Who is doing the work at CTN? Does anyone know if permits have been pulled?

I’ve been monitoring the Miami Herald podcast on the CTS collapse Episode 5: Seven Minutes to Collapse is worth listening to because they interview Dr. Dawn Lehman, the structural engineer the MH hired. It kicks off with the WaPo interview with Chani Nir of 111, and features a very dramatic description of the collapse sequence by the MH reporter Sarah Blaskey plus a very colloquial translation of the Nicolas Vazquez statement. There’s a very good description by Adriana Sarmiento, who shot the TikTok video at 1:18 AM, of the wind that came out of the garage when the deck collapsed.

I still dispute the MH contraction of the timeline: Chani Nir’s contemporaneous interviews stated that she heard banging when she got home at 11 PM, but the Miami Herald doesn’t start the timeline until 12:50 PM. Also Sarah Nir’s original interviews stated that the loud bang (which Gabe called the first collapse) occurred at 1:10 AM instead of 1:14 AM, when she went to the lobby.

The MH now says that Sarah Nir was able to see the pool deck had collapsed all the way to the southern perimeter wall. Sarah never made this claim at the time of the collapse. I feel skeptical that Sarah was able to see through the dust and dark at that time, and would like to hear Sarah make that statement herself, rather than hear a reporter make that claim.

Next week, Episode 6 will be Ileana Monteagudo of 611 and the late Cassie Stratton of 410.

Round 1 sold well in print so they're doubling down in podcast form. Again, the engineering model promoted by the Miami Hearld seems to assume the pool slab abutting the perimeter wall rather than resting upon it. I doubt the likelihood of this construction detail.


(from the second link below)

Quote (Sym P. le (Mechanical) 12 Mar 22 02:46)

At the risk of being repetitive, here are the two Miami Herald article links:

1. Original story, headlined "The Herald built a computer model to explore how Surfside tower fell. Here’s what it showed" By Dawn E. Lehman and Sarah Blaskey Updated January 12, 2022 4:45 PM -- per Dawn Lehman, "... describes the timeline of the collapse that we used to support the modeling we did."

2. The follow up story, headlined "The last stand of Champlain Towers South. Computer model, witnesses reconstruct the tragedy" By Sarah Blaskey Updated January 21, 2022 2:31 PM -- per Dawn Lehman, "... the modeling approach and different scenarios that we evaluated."

Agreed. The MH really wants that Pulitzer.

From what I remember seeing the drawings and the photos of the aftermath, the pool deck slab was sitting on top of the south pool wall

From the first link above, it's difficult to reconcile the following statements:

Quote (Miami Herald)

Slab/Wall Connections

... 90-degree hooks were used, which adequately simulated 180-degree hooks called for in the plans

... Slab to perimeter wall connection - No. 5 bars at 12” on center, 90 degree hooks with 18” leg. ... the connector bars were placed at the middle of the slab.

with the plans:



They've set up a sensationalized detachment scheme that allows a > 1" drop along the perimeter wall as a precollapse stress riser.

The drawing seems to show a monolithic corner, between the deck and the wall. The deck does or does not sit upon the wall. The deck does or does not "hang" off of the wall.


spsalso

The problem with having the deck abut the wall is that it sets up different shear scenarios for the slab. The slab rebar layout anticipates the wall supporting the slab (which a monolithic pour is consistent with). There are plenty of issues at play but MH's introduction of this nonstarter (my opinion) is not good for discussion or journalism.

The monolithic joint shown in that typical retaining wall detail is not a viable detail. Walls and slabs are never placed in a monolithic pour like that. Most likely the contractor would have flagged this in an RFI and asked the engineer to provide a construction joint at this location. Either a vertical CJ at the face of the wall, or a horizontal CJ at the soffit of the slab. The rebar detailing shown is also quite bad.

It is a retaining wall with sheet piles it is not structura. Damn non of you have actually designed or built anything.

Not structural? Please explain.

Quote (bones206)

The monolithic joint shown in that typical retaining wall detail is not a viable detail. Walls and slabs are never placed in a monolithic pour like that.

Have to disagree... slabs are poured with monolithic thickened edges, depressed beams, and stem walls all the time. It wouldn't necessarily be my first choice to do it that way, but it can be done without much drama.

Quote (bones206)

Not structural? Please explain.

Don't feed the troll. We've been down this road before with this guy.

Already regretting I dipped my toes back into this pool.

I agree that certain vertical elements can be placed monolithically with slabs (like thickened edges, etc.), but I would find it very unusual for a basement-type wall to be placed monolithically with an elevated slab.

Quote (Keith_1 (Structural) 12 Apr 22 08:11)

It is a retaining wall with sheet piles it is not structura. Damn non of you have actually designed or built anything

These 15 or so threads have been unbearable at most times, nor am I an expert designer, rather a curious one parsing through the crumbs that are out there for us to feed on.

The point I was trying to raise was whether it was constructive to model a vertical shear fracture of the slab at the interior face of the perimeter wall for analysis purposes or how such a structural defect would evolve.

From a structural design standpoint, does the slab diaphragm not offer lateral support to the tower structure and as such require adequate connection to the perimeter vertical elements?

See my post from 25 Jan 22 07:10 in part 15 for the full drawing sheet which shows the pile layout, as well as the perimeter retaining wall cross section which gives insight into how the pool deck level slab transferred load through the retaining wall and down into the outermost ring of piles below the basement level slab.

I don't think as a group we know for sure that the pool-deck-level slab was a critical structural element from the standpoint of maintaining stability of the building itself, because no one has done the big heap of math needed to figure that out... but based on the pile layout and the detailing at the joint between the perimeter retaining wall and the slab, it appears that one of the following is true:

1) the pool deck level slab was a critical element for maintaining lateral stability, and its failure put the foundation system into an unstable condition (in other words, sawcut out the pool deck slab and the building is now unstable)

2) the pool deck level slab itself was not critical for maintaining stability of the foundation system, BUT the failure of the pool deck put unaccounted for horizontal load into the foundation system through catenary action as the slab came down, and those horizontal loads caused localized failure(s) at the joint between the exterior pool deck level and the perimeter of the actual building, and those horizontal loads and localized failures put the building into an unstable condition (in other words, if you sawcut out the pool deck slab the building is stable, unless you then put some big horizontal loads into the top of the basement columns)

Quote (Sym P. Le)

The point I was trying to raise was whether it was constructive to model a vertical shear fracture of the slab at the interior face of the perimeter wall for analysis purposes or how such a structural defect would evolve.

Yes, I understood your point. In my reply, I was trying to explain how that joint may have been constructed with a cold joint at that location. This isn't necessarily a defect, as cold joints (aka construction joints) with rebar dowels are commonly used in construction. If there were a construction joint at this location, it should be readily determined from an examination of the joint. I remember when the event first occurred, photos (although taken from a distance) seemed to show a clean vertical break at this joint in some locations. It could very well have been a vertical construction joint with steel dowels taking the gravity load.

The ground level slab may have been considered as a brace point for the building columns, but I would expect the columns could still survive if the slab was hypothetically removed from the analysis. But failure of the slab I agree could impose some lateral loading on the columns, which could initiate a collapse. I tend to believe the slab collapse progressed from the property line until it took out that one slender column near the planters, causing one end of a beam to drop and wrench down on one of the main building columns.

I haven't been following closely for a long time and have just been waiting for the investigative report to be published.

Per the Miami Herald, Surfside’s new mayor implies they may cut KCE loose.

Surfside became known for deadly condo collapse. Now the town looks to champion reforms

I hope you don't mind me jumping back in here.

Quote (SwinnyGG)

1) the pool deck level slab was a critical element for maintaining lateral stability, and its failure put the foundation system into an unstable condition (in other words, sawcut out the pool deck slab and the building is now unstable)

I believe that if the saw cut was made first along the North side of the pool deck, it would isolate the north wing of the building from collapse. Cutting the East, South and West sides of the pool deck / parking deck first would allow columns to punch through and eventually the deck becomes a massive lever, torquing the columns on column line 9.1

Quote (SwinnyGG)

2) if you sawcut out the pool deck slab the building is stable, unless you then put some big horizontal loads into the top of the basement columns)

I imagine that as columns punched through, the deck is located by them. If the deck is inclined, lower in the south and higher in the North (at the connection with the building) geometry dictates that either the deck must stretch (but it is extremely stiff) or the columns along column line 9.1 are pulled to the south.

The Miami Herald is going after the building next door. ‘[Bleep] that wall,’ contractor said when vibrations near Surfside condo got ‘too high’

Certainly seems relevant, given the hypothesis that failure initiated at the slab/wall joint along the property line, which happens to coincide with the location of excessive piling vibration.

Quote (MaudSTL (Computer))

The Miami Herald is going after the building next door.

The vibration limits are intended to prevent effectively non-structural damage (stucco etc). According to the quote in the Herald, Wiza was talking about replacing a wall, not stucco. That's the basic problem. It's a damning statement.

Quote (MaudSTL)

The Miami Herald is going after the building next door.

Interesting article. Thanks for sharing MaudSTL.

Quote (zebraso)

Wiza was talking about replacing a wall, not stucco. That's the basic problem. It's a damning statement.

It's a "damning statement" that he is willing to replace a concrete block privacy wall, in order to move his project forward?

That would be a wall that is completely non-structural. And it's my impression that it has mostly not even fallen down. Unaided.

Perhaps he should get a gold star for doing whatever he did so as to ensure that wall did NOT fall down.

I am not understanding how Wiza's actions are the least bit connected to the collapse of the building.


spsalso

It's a damning statement in that it shows a total disregard for the policies that were put in place to protect adjacent properties.

And your thoughts about the seismologist who kept working there, even when he knew those policies were being violated?

And also your thoughts on the seismologist not (apparently) reporting his concerns to management higher than Wiza, or the City? Or anyone?


spsalso

It certainly looks like he was checking a box to collect a paycheck. I wonder who actually wrote the log entry wiza or the seismologist. I assumed the seismologist wrote it to cover his ass, if that was the case good for him. If a licensed professional was involved things may have been handled or at least documented differently.

I suspect that Wiza thought that it would be a far better choice to replace a concrete block privacy wall than to stop the project, especially since it appears he had noted no structural damage up to that point (He was apparently worried about the area near the pool, which he had then completed). It's entirely possible that the seismologist agreed.

After the fact, it appears the wall was not damaged enough to replace it. Surely the CTS tenants would have complained if it had needed it done.


spsalso

The Superintendent stating that he was willing to make repairs to an adjacent structure means absolutely nothing. It's a complete red herring. We do it alllllllll the time. On my current project I'm about to replace a fence and some bushes on the property of a dude who took it upon himself to landscape in the public ROW, specifically because it is cheaper and a more efficient use of my time to replace his bushes than it is to tell the guy to pound sand and spend the next 6 months getting calls from the city after he calls them to bitch.

Unless someone can demonstrate that the pile driving operation next door actually caused damage to the Champlain Towers foundation system, this is a false hole to fall down. In his shoes, I would've done the same thing and probably used the exact same obscene phrase to instruct the crew to continue their work.

Quote (SwinnyGG (Mechanical))

...make repairs to an adjacent structure

....ummm. Structure??

Quote (spsalso (Electrical))

It's a "damning statement" that he is willing to replace a concrete block privacy wall, in order to move his project forward?

I am not seeing the words "CMU", "concrete block", or "privacy" in the quote. He is not making a distinction. But even if he was it would be just as curious. How do you damage the CMU wall, without going through the perimeter basement wall with the vibrational force via the earth? It's another matter yet to define whether a CMU wall is a "structure" in its own right in regard to the vibration standards. It's clearly not the same type or level of damage to replace stucco vs relaying/replacing a block wall whether or not it supports a roof. And it was stated by a structural engineering consultant in one of the links Maud provided that the concrete at the top of the perimeter wall, (post collapse) shows signs fracturing from intense vibration force in the area of concern. The only thing that is left is to determine whether that wall is "structural" in a strict sense, and it seems there is a certain faction here that strongly believes it is.
Having said all that I'm not sure the idea that the wall has "mostly not fallen down" is a test that could be written into any standard.

Edited once for clarity.

There was a five year gap between the time of pile driving and the collapse. Everyone is worried about the time noises appeared. If it was quiet for five years previously I don't think you can reach back five years for a culprit. I worked for a company sued by a bank that said pile driving several years earlier was what caused their building to develop cracks. A check of records showed pile driving was done before their slab was even poured.

" How do you damage the CMU wall, without going through the perimeter basement wall with the vibrational force via the earth?"

The only damage to that wall that was described in the article was done previous to the pile installation. I don't see anything about it being damaged BY the vibration from the pile installation.

"... the concrete at the top of the perimeter wall, (post collapse) shows signs fracturing from intense vibration force in the area of concern."

As far as the concrete at the top of the wall being damaged by intense vibration force, a person could wonder whether there was any such vibration when the building fell down. I am surprised that the wall stood at all.


spsalso

Quote (zebraso)

....ummm. Structure??

Semantics.

Quote (spsalso)

I am surprised that the wall stood at all.

How many times was this wall rebuilt over the life of this complex? There were at least some sections that blew over in Hurricane Wilma in 2005 (video appears to show the failure of the entire eastern section abutting the pool deck, shown approximately 3:30 in https://youtu.be/X4BwnI0VyPM). Do we know if that was the original wall, or if it had sustained damage previously and/or subsequently due to tropical force winds? I can't recall how thoroughly that was hashed out here.

Infiltration was a known issue at this location on site, as was shoddy construction and maintenance. I have little faith that any potential damage to the connections at the pool deck and subterranean structural wall was repaired properly if at all. I'm sure the vibration from the pile driving didn't help, but it was likely just another irritating factor on top of decades of neglect and mediocre construction. This entire disaster should be seen as a cautionary tale, but we know how that goes.

Looks like insurance companies are raising prices for condos in the area, if they'll even renew policies at all. The Florida legislature seems to be getting the free market solution they wanted when they declined to improve inspection requirements.

Quote (Phil1934)

Everyone is worried about the time noises appeared.

To clarify, this was a building that made noises over time…it was not silent until the 24 hour period described in the Timeline spreadsheet. Residents specifically complained during the period of construction next door (which started 2016) and also during the roof work that was going on when it collapsed. At the time of the collapse, there was an interview quoting a resident stating that the building always made sounds, but I don’t have a citation or know how long that person had lived there.

And speaking of timelines, not sure Josh at BI has it exactly straight in his video re the wall connections. Please correct me if I'm wrong but I don't think the timeline establishes that any of the pool-adjacent area collapse could have been visible to folks driving into the garage pre- the overall building collapse, or was seen for sure by residents above. Aside from the timeline matter, if a portion of the pool deck had collapsed leaving enough standing to drive around under obliviously, the catenary force on the columns would have been reduced commensurate with the area of deck already on the ground. Don't we need the whole catenary, +/- the reaction perhaps of the wall connection letting go, to bring the building down?

Quote (AusG (Petroleum))

catenary force on the columns would have been reduced

In this scenario you are stating the wall disconnection at most should provide stress relief to the remainder of the deck support, stabilizing it or isolating it from certain forces...all else being equal. And I guess by "equal" I mean not delaminated, spalled, corroded, or otherwise dilapidated. etc. Posing this as a question so I can understand. Or maybe that is reading too much into it. Do you mean that the entire deck in more or less one piece is simply required to generate the required vertical catenary. And I am sort or reading as a question that the shock wave of the wall disconnection is involved in getting the process going (stack of cards thing). Sounds like a new brain stormer. Who is going to model that?

If the catenary force of the concrete deck brought the building down, it would have happened right away. There would not have been a several minute wait.


spsalso

That's not necessarily true... it depends on the relationship between the applied load, the ultimate strength of the structure, and the level of ductility available to absorb load over time.

I'm comparing two scenarios. The first has the pool deck columns no longer carrying full load due to punching shear, the resulting catenary (plus some thermal shrinkage overnights) is being held by the building columns and the wall connection, one of of which fails and the reaction breaks the other one. The other scenario, which I think is Josh's, is that the wall connection failure, triggered by the thermal shrinkage and weakened connections, predates and precipitates the punching shear which then eventually brings down the building. Both are clearly plausible but his diagrams had some sections of the pool deck fully collapsed minutes before the building, and my feeling is that would have lessened the catenary pull on the building columns and so eased their stress.

Quote (AusG (Petroleum))

I'm comparing two scenarios.

Thanks for clarifying that. It's a complex thing with multiple elements ready to go super critical. The idea that I have a bit of trouble with is that the wall was compressing the deck and and holding the whole thing together. But then from what Josh was describing that is not very likely in terms of the failures. i.e. that the wall was not a required structural element in that sense. You are I think looking at it without that idea being incorporated at least. So anyway I get you are talking about what more likely fits the timeline. And of course the ductility is in that. If the perimeter wall is not holding the building up (wild theory there) it's a little harder to explain, in simple terms.

New FIU bridge designs revealed, four years after fatal collapse

06 MAY, 2022 BY ROB HORGA

Upps, wrong thread. I'll climb back in my teapot now...

SF Charlie
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Members of the public may attend the June 9 NSCT Advisory Committee meeting to get the status of NIST’s investigation of the CTS collapse! Here’s a link to the announcement and agenda. You have to sign up before May 31, and you don’t need to be representing any organization.

Quote (AusG)

…his diagrams had some sections of the pool deck fully collapsed minutes before the building, and my feeling is that would have lessened the catenary pull on the building columns and so eased their stress.

Sorry, I haven’t been staying caught up.

From a witness statement perspective, a two-stage deck collapse doesn’t work. The Vazquezes drove into the garage, parked (I still have not found out which space they parked in,) walked to the elevator lobby, heard loud cracking sounds, and got into the elevator just as the deck collapsed at about 1:15 AM. They have never reported seeing any evidence of fallen concrete in the garage in the minute or two before the collapse.

The loud crashing sound that Security Guard Shamoka Furman heard in the lobby and the Nirs heard in 111 occurred at 1:10. Because the Vazquezes saw no evidence of collapse, could the 1:10 sound have been rebar failure at a column or at the south wall?

Note that none of the witnesses talked about banging or crashing sounds in the five minutes between 1:10 and 1:15. I doubt that anyone has asked the witnesses what they heard in those minutes.

From the Pulitzer Prize winning Miami Herald, Lawyers in suit over Surfside collapse reveal staggering legal settlement: $997 million. This is just the insurers. The sale of the property will bring it over $1B. The security company Securitas paid the most.

It will be interesting to learn NIST’s findings someday…the Miami Herald states the failure of the connection of the south perimeter wall triggering the deck collapse as a fact.

One of their reporters called me up this week to tell me that the Miami Herald timeline deviations are insignificant and must surely be the result of expert advice they have received from people they have hired, as opposed to actual witnesses describing their lived experiences.

Reporters aren't too bright. The exception might prove the rule.

spsalso

A couple of articles list "an engineering firm" LINK as one of the defendants. I'm curious if there is any information on which engineering firm this is. Any information on that? Would it be the firm that performed the previous inspections or repairs? Or possibly a firm related to the construction of the adjacent building or original construction?

Quote (RFreund)

I'm curious if there is any information on which engineering firm this is.

If you scroll down in the Miami Herald piece, there’s a list. Morabito is one, but there’s a structural from 87 Park listed too.

The developers of 87 Park get to keep their settlement amount a secret because they are only contributing to be nice and make the lawsuit go away…they maintain they are not liable.

I see, interesting, thanks.

Josh Porter is featured in this Miami Herald subscriber-only bombshell article, Surfside condo was ‘screaming’ as an alarming crack formed just weeks before the collapse. There are photos taken about a month before the collapse showing severe cracking in the planter by the parking deck. The archive I made in this link only shows a teaser rather than the entire article. Perhaps a subscriber can copy it out for us.

>>>>>Edit: A subscriber in a FB group I monitor copied out the text.

SURFSIDE CONDO WAS ‘SCREAMING’ AS AN ALARMING CRACK FORMED JUST WEEKS BEFORE THE COLLAPSE

By Sarag Blaskey, Ben Conarck, Nicholas Nehamas
Updated May 14, 2022
Less than a month before Champlain Towers South collapsed last June, the building manager noticed something that made him pause on one of his near-daily walks around the property: A large horizontal crack, maybe 20 feet long, had formed in the planter along the western edge of the pool deck.
So he called a structural engineer working for the building to come check it out.
The long crack hooked upward on one end in a gaping vertical fracture as if the planter was being torn apart at one corner, photos taken during the June 8, 2021, inspection and included in court records showed. The concrete-block wall on one side of the vertical crack appeared to be about an inch lower than the other, as if part of the planter had started to slump into the garage below.
The planter itself did not play a role in the building’s structural integrity. But the dramatic change in the height of the wall on one side of the vertical crack suggested the structural slab below could have been starting to fail a possible canary in a coal mine warning of the deadly collapse that would happen on June 24, six structural engineers who reviewed the photos told the Miami Herald.
A cracked planter alone isn’t enough to cause major alarm, the experts said, but the slab nearby had been showing signs of distress for months. Photos exclusively obtained by the Herald show water had poured through the slab, cascading down a column supporting the pool deck just 20 feet from the planter. The file names suggest the photos were taken in November 2020. Josh Porter, the president of Punta Gorda-based Consult Engineering, said the photos from November were already “evidence of imminent collapse.”
“This building was definitely screaming that it was in dire straits,” said Porter, a structural engineer who specializes in restoration of high-rise condo buildings.
His concern was more than water damage to the column.
The amount of water streaming down it was a sign that the slab was already severely cracked around the top of the column, Porter said. It looked to him like the slab might soon break away from the column supporting it. “Most engineers would say this is a serious problem: Part of your pool deck could collapse,” Porter said.
The crack in the planter months later suggested the problems in the pool deck slab had likely worsened, although more inspection was necessary to be certain the two problems were linked, the engineers consulted by the Herald said. Although it’s unclear exactly when the problem in the planter started, a photo dated April 20, 2020, shows no vertical displacement between the two planter walls and no cracking at all. “That’s a lot of movement in one year,” said Florida engineer Nestor A. Cueto of Miami-based Cueto Engineering. “If it was noted that significant movement of that area occurred after the previous inspection, that would be a cause for additional investigation.” Cueto, who performs 40-year inspections, said that given the other problems in the basement, he would have also requested temporary emergency shoring while simultaneously investigating the underlying cause of the crack. The town of Surfside requires a permit to place temporary shoring, which generally involves positioning adjustable, steel support jacks to relieve some of the pressure on weakened structural elements.
A spokesperson for the town’s building department confirmed no permits for shoring were taken out for Champlain South in the month before the collapse.
On June 24, just two weeks after the cracked planter was discovered, the slab broke away from the columns a type of failure known as flexure-induced punching shear that the engineers told the Herald was both predictable and likely preventable based on what they observed in the photographs. The planters and pool deck crashed down into the underground garage below, kicking off a chain reaction that resulted in the collapse of most of the 12-story residential tower. Ninety-eight people died.
MISSED SIGNALS
Scott Stewart, the building manager of Champlain South since 2019, kept a close eye on the structure that was approaching its 40th birthday. “We did a property walk almost every day for safety of the property,” Stewart told the Herald in an exclusive interview. Whenever he saw anything out of the ordinary, Stewart said he immediately called Frank Morabito, the engineer first contracted by the condo association in 2018 to inspect the building in preparation for the required 40-year recertification of the structure. Records show Morabito and his team inspected Champlain South frequently between 2018 and 2021, taking photographs and writing nearly half a dozen reports noting the pool deck slab was in urgent need of repair.
Despite the building’s history, when Stewart called about the cracked planter he noticed early last June, the manager said Morabito wasn’t worried and told him the problem could wait a few days until the next scheduled visit. “Discussing it with the engineer, it wasn’t determined to be an emergency situation,” Stewart said. “So when the junior engineer came out to do the inspection of the roof, he [Morabito] had him look at it then.” The inspection of the planter on June 8 didn’t last more than 15 minutes, Stewart said. He said Morabito determined from photos sent by the engineer on site that the problem was cosmetic and caused by roots penetrating the cracks of the decades-old planter.
“It was determined there was no immediate action needed,” said Stewart, who appears in one of Morabito’s photos from the day. The planter would be removed as part of the overall renovation plan just getting underway at the tower, he said.
Stewart said he remembered seeing some roots in the crack, but engineers consulted by the Herald say that wasn’t enough to determine the cause of the break definitively. “Part of these visits was to monitor the building, so if you see a significant change in something, that should be a red flag,” said Dawn Lehman, professor of engineering at the University of Washington and a consultant on the Herald’s collapse investigation. While it is possible that roots damaged the planter, it is not the only explanation for the gaping crack, nor even the most likely given the timeline and condition of the slab below, Lehman said. “If you come in time and time again and you see a change, you don’t make an assumption, you do your job,” Lehman said. “The building was talking to Morabito and he wasn’t listening.” Given previously documented evidence of damage to the slab in the area and how rapidly the cracking formed in the planter, engineer Shankar Nair said Morabito’s team should have considered potential structural causes.
“I believe this was a very serious warning sign,” Nair said. “If the structural engineer saw what I see in this picture [of the water coming through the slab] and then saw the crack in the planter … he should have put it together.” At the very least, Nair said engineers should have checked the slab for evidence of structural problems. Problems with the slab would have been obscured from view from above by planters and decorative pavers on the pool deck. So, experts said, Morabito’s team should have gone to the basement-level garage to look up at the slab from below, where cracks, sagging or other more definitive evidence of structural problems would have been more obvious. “If he didn’t, that would be on the edge of being irresponsible, to not run downstairs right away,” Nair said. “He absolutely should have done that.”
But Stewart told the Herald he didn’t remember anyone from Morabito’s team going to check the slab from below after they photographed the cracked planter on June 8. He would know, he said, because he would have been the one to bring them down there. Nor was there any immediate plan to tear up the pavers and planters to look at the slab below them something that would not begin until phase II of Morabito’s restoration plan, documents show.
The photos of the cracks in the planter wall were included in exhibits filed as part of a massive class-action lawsuit seeking compensation for unit owners, survivors and relatives of those who died in the tragic collapse. “Proper and immediate shoring under Morabito’s direction may have prevented the collapse of the entire building,” according to the filing by Stantec, the architects of Eighty Seven Park a luxury condo tower next door to Champlain South that victims partially blamed for the collapse. All the firms associated with Eighty Seven Park denied that their construction project had anything to do with the collapse, which happened years after construction ended.
“Certainly, Morabito should have immediately evaluated the condition and stated its structural engineer[ing] conclusion as to whether the partially collapsed planter required immediate and emergency shoring,” the filing continued. On Wednesday, Champlain South’s court-appointed receiver announced that the plaintiffs and defendants, including Stantec and Morabito, had reached a global settlement of nearly $1 billion. None of the defendants admitted wrongdoing. Morabito will pay $16 million through its insurance firm. The plaintiffs had accused the firm of failing to warn residents that the building’s structural problems necessitated immediate repairs. and possibly even evacuation.
A spokesperson for Morabito Consultants did not respond to the Herald’s specific questions about what actions were taken after the crack in the planter formed and whether there was any investigation of the area below the planters, but defended the firm’s work and reputation. “Morabito Consultants are structural engineering experts with a well-earned reputation in the industry,” Brett Marcy, the spokesperson, said in a statement to the Herald. “We share the desire to better understand what may have caused this tragedy, and we are hopeful that the global settlement announced today between the many parties involved will bring some closure to all those impacted by it.”
Records show Morabito warned the condo association about structural problems at the building. But in a court filing the association said he never determined whether the building was “safe, safe with qualifications, or unsafe,” as required in his contract. The federal National Institute of Standards and Technology continues to investigate the cause of the collapse, although its report may not be released for years.
AN EXPERIENCED ENGINEER
In the spring of 2020, the Champlain South condo association met under mounting pressure to do something about the laundry list of deferred repairs that were becoming impossible to put off any longer ahead of the building’s 40-year recertification. The association was chiefly considering hiring Morabito, a reputable engineer from Maryland with decades of experience who was establishing a foothold in South Florida in the latter stages of his career. Morabito describes himself on his website biography as a dual citizen of Italy and an active philanthropist of Italian charities.
“Some might be surprised by his skill on the billiard table, though he’s more likely to be found playing golf or reading golf books while enjoying a glass of red wine,” the biography reads. Morabito spent the bulk of his career expanding his business in Maryland with his two brothers Fred and Anthony all of them having University of Maryland degrees. In 2018, Morabito pivoted to South Florida as his primary business hub. His state license is active, and he first registered his company with Florida regulators in 1990. Huddling in May 2020, the Champlain South condo board noted that a prior board had already hired Morabito to perform an inspection on the troubled tower, which went well enough to earn him a recommendation from the association’s 40-year committee. The board ran several reference checks on Morabito, citing various South Florida projects he had worked on. The feedback was overwhelmingly positive, though he had been described by one person as expensive.
It wasn’t noted in the board’s presentation, but Morabito did battle one high-profile lawsuit in his career. In the late 1990s, the College of Notre Dame of Maryland sued Morabito Consultants for negligence and breach of contract over a 1991 renovation of Gibbons Hall, an administrative building on campus. The project included converting residential space on the fifth floor into classrooms and offices, and Morabito Consultants was hired to perform the structural engineering. Several years later, in 1997, a separate engineering outfit performed a routine inspection and described “significant movement ‘internal to the building’ on the fifth floor,” according to the lawsuit. The firm concluded that Morabito Consultants failed to properly calculate the increased load brought about by the change in building usage, causing the building’s trusses to become overstressed. A Maryland circuit court and appellate court both dismissed the suit, saying it was filed after the statute of limitations had expired. Abieyuwa Aghayere, a Drexel University engineering researcher, said that type of mistake was not a run-of-the-mill mix-up, based on his review of an appellate ruling. “You typically would design for the new load and check it, and maybe reinforce the [trusses] if need be,” he said. “The fact that [Morabito Consultants] didn’t do that here is concerning.”
Aside from that lawsuit, Morabito Consultants earned favorable marks from the condo buildings that Champlain South checked with. On his website, Morabito cites his favorite renovation project as the Dolphin Towers condo renovation in Sarasota, which had been evacuated in 2010 after a giant structural slab between the third and fourth level failed. Morabito Consultants was called in to help fix the condo tower. Jim Toale, the president of the condominium association, said Morabito was hired by the contractor who handled the Dolphin Towers renovation, and came up with a solution for the issue with the slab. While he was there, Toale added, Morabito flagged warning signs of punching shear in the parking garage, prompting future repairs. “We’ve had no issues with Morabito,” Toale told the Herald. “What they fixed, it’s still solid.”
A BUILDING ‘CRYING OUT’
In November 2020, Stewart, the building manager, was touring the underground garage with someone from Morabito’s engineering firm. It had just rained, Stewart said. And, as usual, puddles covered the floor, proof of the failed waterproofing on the pool deck, which Morabito had noted was causing “major structural damage” to the slab. In one report, Morabito said urgent repairs were needed to prevent the problems from becoming exponentially worse. That day, the engineers focused on an area around one column in particular a 12-by-16-inch pillar of concrete painted with the number 76, demarcating a parking space in the middle of the garage. Photos taken that day showed water streaming down the column, causing the paint to run and sediment to build up at its base. “We were trying to figure out basically where the moisture was coming from,” Stewart said.
Other columns around the garage were sometimes wet, mostly from leaking pipes, the manager said. But column 76 was by far the worst. One engineer who looked at the photo for the Herald called it a “waterfall.” Stewart said Morabito’s team snapped the pictures of the column and slab above it to include in a bid for the upcoming concrete restoration process set to begin the following year. But if they had more immediate concerns about the structural integrity of the area, they never told Stewart.
They took the pictures and then did “nothing” more, Stewart said. Morabito made no mention of the column in any reports to the board reviewed by the Herald. “It’s shocking,” said Aghayere, the Drexel professor. “This column was almost crying out; it was the structure crying out saying ‘fix me, do something about me,’ ” he said. Knowing that the structure was poorly designed, with almost no redundancy, Aghayere said the problems documented in the photographs that day “would have scared the daylights out of me.” “I would have shored it up with a goal to evacuate the building, knowing what I know about the structure and how it was designed,” he said.
The western half of the pool deck, which caved-in on June 24, was held up by narrow columns placed up to 30 feet apart to maximize parking space in the garage below. It was a flawed design that left the 9.5-inch concrete slab cracking and bending under its own weight from day one, computer modeling by Lehman, the University of Washington researcher, showed. The building designs had originally included beams to support the planters from below, but they were removed in the final drawings, leaving the slab and columns alone to support the boxes of heavy wet earth.
Over the years, pavers and sand were layered on top of the original tiles, permits show, adding more weight to the overburdened deck. Roots from the planters penetrated the slab and cracked drain pipes causing water damage to the concrete and reinforcing steel bars within it, records show. Post-collapse photos show the connections between the slab and columns did not contain all of the reinforcing steel that was called for in the plans, reducing the strength of those critical connections. Photos also show damage and corroded rebar along the deck’s connection to the southern perimeter wall, which experts said played a role in the overall structural stability of the tower. In a well-designed structure, experts said the localized failure of a pool deck should not cause the collapse of a whole tower. But at Champlain South, the design defects, construction errors, damage, degradation and poor maintenance came together in a perfect storm leading to one of the deadliest collapses in modern history. It began when the deck collapsed at 1:15 a.m. Columns punched through the slab, which disconnected from the southern foundational wall. After losing that critical connection, computer models showed damage propagating into the tower.
But missing from the public understanding so far has been what initiated the collapse. The collapse could have been triggered by column 76 suddenly punching all the way through the slab, as it had apparently been threatening for months, engineers said. Or, they said, some failure of the connection between the deck slab and structural perimeter wall or elsewhere could have triggered the punching shear at column 76 and across the western pool deck. “Are we ever going to know what the very first thing was? I doubt it,” said Porter, the Florida engineer, who has studied the collapse extensively and posts his findings on a popular YouTube channel. “Whether [column] 76 happened before the south wall failed, or vice versa, you’re going to end up with the same result.” Regardless, if the connections between the vertical and horizontal elements of the structure had been stronger and the columns had never punched through the pool deck slab, it’s possible the deadly collapse of the tower would have never happened at all, engineers agreed. “This could have been prevented,” Aghayere said.
Porter cautioned against assuming the warning signs were as clear without the benefit of hindsight. No one would have expected the building to fall down solely because of a partial pool deck collapse, he said. “When you do this for 30, 40 years and see horrendous buildings and bridges and none of them collapse, you end up with this false paradigm that buildings can’t collapse,” Porter said. “You’re so stuck in that paradigm that you can’t fathom that something catastrophic is about to occur,” he said.
#FeaturedArticle #investigation #CTS
https://www.miamiherald.com/.../sur.../article2613...

I don't know the proper etiquette for posting this, but I attached a PDF since the site let me read it for some reason. I'm in a completely different field (IT engineer), and mostly was lurking here, but have found this fascinating and interesting

(Also, amusingly, had an issue with the file name uploading this. Got a 500 .net error, I assume from | or some other default symbol from my PDF print original filename)

• https://files.engineering.com/getfile.aspx?folder=34bbf969-34ca-4812-9cb1-8

If that isn't news, I don't know what is! Who here guessed that this was an area of concern? I think I heard it first from Structural Madness on Youtub.

It also puts to shame the prior MH exposé supposing that the slab sheared at the south perimeter wall first.

Quote (MaudSTL (Computer))

There are photos taken about a month before the collapse showing severe cracking in the planter by the parking deck.

Those photos are incredible. I can't recall that ever being seen widely such as on this form or previous links. that could be the early predicate of a E-W catenary. There is a sudden step change the deck height from that point east. The long crack going north has not dropped much. So the entire progression *to* the S perimeter and step beam may have happened over weeks. This might argue that the deck started to collapse well before the wall disconnection. Unbelievable that this photo was not widely seen until now...nor witness statements about what it shows.

Thank you, stcbus! My, Morabito must be glad his insurer has already settled; this piece really nails him. I wonder if criminal charges are under consideration…is that even possible?

>>>Edit: Yes, we can thank Jinal Doshi of Structural Madness for identifying this area long ago. Here is his video, which he posted around August 2021. https://www.youtube.com/watch?v=fFQ7ey5CDLc&t=...

So thirteen (my bad) sixteen days prior to collapse, Morabito photographed the cracked planter.




Even more telling is that the crack in the planter is absent above the column upon which it sits. This would indicate that the punchout is in progress.




Markup transferred to aerial




The remains of two columns supporting the planter in question.




Meanwhile, I was looking at the 29/30 column. The damage previously photographed was either repaired or did not progress through to collapse.

Quote (MaudSTL (Computer))

this piece really nails him

And yet one has to wonder to what extent he could or should have realized this put the entire structure at risk. To what extent could he have imagined that? Yes he should have shored the deck and the deck should not have collapsed.

Quote (Zebraso)

And yet one has to wonder to what extent he could or should have realized this put the entire structure at risk.

The piece closes with Josh warning that most engineers would not imagine that such damage would lead to collapse, as everyone has seen buildings with similar or worse deterioration. But before the closing, the MH practically slanders Morabito via critical comments made by various engineers, at least some of whom are on the Mh payroll.

Thanks. I guess I must skim read and skipped the ending. Interesting. I was thinking (dangerous I know); if the only result was the deck collapsed and the building survived at least long enough for people to evacuate, then due to serendipity there was no one in the garage at the time. If only.

Quote (Sym P. le (Mechanical)15 May 22 01:51)

So thirteen days prior to collapse, Morabito photographed the cracked planter.

WOW!

SF Charlie
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Never mind, I got turned around. The colored tile probably leads to the hot tub and is probably under the pavilion in the overhead photos,
My apologies to the MH
In this MH photo in 2020 we see stanchions and colored tile.

In this USAToday photo we Don't see the colored tile, we see paving for parking leading to the vestibule of the office.


I think the MH miss located the planter in their photo.
No they didn't

Please see "area detailed:

from a real estate site:

As MaudSTL mentions, the story closes with: "Porter cautioned against assuming the warning signs were as clear without the benefit of hindsight. No one would have expected the building to fall down solely because of a partial pool deck collapse, he said."

Without hindsight, would any of those who are stating the Morabito firm was negligent have foreseen the tower being at risk using the observations at hand? The pool deck is showing signs of poor drainage and corrosion, the pool service area is in need of rehab and some planters are cracking and/or sagging. Would that immediately have raised concern the tower is at risk? For the age of the building, were the misalignments of door frames, cracks and reports by some residents of creaking/banging noises obvious indications of impending failure? Or is it all clear to the observer, now with knowledge of the actual collapse?

The Champlain collapse appears to be a failure that is going to change (or should change) the analysis and methods used for building design and structural integrity evaluation.

How many feet from this sinking deck is the weight of a vehicle being placed? Maybe 5 feet? It's not the first thing I thought of when I saw this. So this is essentially a parking deck at this point. How can anyone not see that as the punch at the nearest column on a deck that is supporting cars and trucks next to it. Isn't that what it really is?

What I'm curious about is why or how the column that was supposedly under the wall, punched through east of the wall?

SF Charlie
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I am guessing you are referring to the progressive punching of the deck to the east beyond this planter located column. as in why didn't the planter just fall through and be done with localized damage? Yeah, Josh I believe in the article said you must run right down to the basement there and look up. The next question I can think of is if he did that where is that photo? So we assume I guess he did not. That photo would largely answer your question. Pavers are hiding the answer on top.

What I meant to ask is, how did the column punch through with the planter wall sitting on top of it? Did the top of the planter rotate west? If so, did the deck break before thee punch through? Or did the top of the column shear, and lean east, allowing the planter wall to fall?

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Quote (zebraso (Mechanical) 15 May 22 20:13)

... a deck that is supporting cars and trucks next to it. Isn't that what it really is?

I've been aiming at that for quiet some time. The photo of the planter now brings this to the forefront. It's (the deck) a 30' span that can't support it's own weight and has cars driving on it (the 30' span for all intents and purposes extends into the parking area!)

Quote (Miami Herald)

... the engineers focused on an area around one column in particular ... painted with the number 76 .... Photos taken that day showed water streaming down the column, causing the paint to run and sediment to build up at its base.

Column 76 is the next column east of the planter column. This suggests that two columns have at least partially punched through. This is where Josh's (edit: Building Integrity @ Youtube.com) theory of tensile forces comes into play. A significant area of slab that should be resting on columns is now suspended as though it were a tightrope and is pulling on the building to the north and the south perimeter wall to the south (not to mention east/west). The idea that the south perimeter wall let go first is nonsense.


Column 76, center foreground. July 17, 2020


recently from Miami Herald (photo taken Nov 2020)

Quote (Miami Herald)

“We did a property walk almost every day for safety of the property,” Stewart told the Herald

The property owners were in on the problem. Likely, they couldn't commit themselves to vacating the property unless "told" by an authority to do so. Though unfortunate, it is part of the human condition.

Quote (SFCharlie (Computer) 15 May 22 20:37)

What I'm curious about is why or how the column that was supposedly under the wall, punched through east of the wall?

The planter wall is not a structural component. The slab punches through and the flaky planter wall falls over or is pushed out of the way. If the drawing overlays are taken literally, the planter wall is offset from the column center line anyway.

Without analyzing that too deeply, the thing the occurs to me is the planter wall has no strength. That's why it cracked and broke when the deck lowered under it. The column supporting the planter wall alone is not significant. it's not taking any significant load from the planter wall. I may be off base as to what you are getting at. I mean to say the planter and it's contents are not transferring load to the top of the column via the wall. The planter wall would have given way to the column on the way down. There must be a photo that shows that.

I agree. A scenario in which the planter wall would be structural is if it were cast as part of the slab complete with integrated rebar (as inverted T used as a stiffening rib).

Thought project: The punch out failure in this situation is unconventional - /^-\ as opposed to \_/.

This might have hidden both top and bottom surface indications of its presence.

/-\. Boy it all comes back to the pencil points.

And if we're following the bread crumbs backwards, we now have column 76 punching out first, followed by the planter column (at least by documented evidence).

This is consistent with the column layout with the greatest span south of these two columns at 29'-8". If that span is not properly supported (edit: by the two columns in question), the area of slab affected is roughly 67' x 49'.




As a curiosity, these two columns also create a bulls eye for the deck collapse though likely only since there were interruptions one bay away on each of the four sides.

What is the dark ring around the base of 76 at the slab in the walk through? It's odd looking to me. That pooled water is a haunting thing. Shouldn't there be evidence of staining or dirt on the column if sediment is following the water as was stated? Something is odd in that photo.

Edit: is that pipe coming down the plater column from the planter drain. It dumps onto the floor? If so I am not surprised it is dry under it.

Edit again: the actual drain is slightly s/e of the column. But I guess if you were going to dump it you would route it over to a column. And that's the closest one. That's not the only pipe down column I noticed in the walk through. In fact I don't think I noticed that one until now. I just can't recall that it mattered much.

That wall is over K13.1 (Space 75) which was the most heavily loaded column on the deck and is one of the two possible initiation points for the punch shear. See Igeezers post in PT 15. The crack is consistent with the middle of the deck trying to butterfly downward like it ended up post collapse.

> The punch out failure in this situation is unconventional - /-\ as opposed to \_/.

Yes, I mentioned this several threads back and said I would put some reasoning into what that might mean, but I never got around to it, did I?

Amazing that this pic has just come out now. It seems to clearly show the planter has dropped a long way, maybe 2", at its NE corner. Hard to see how that's possible without the slab already starting to detach from that column just to the N. And while it might only be clear in retrospect that that puts the building at risk, surely a responsible engineer can see that that was already putting the pool deck (and therefore the garage) at risk, and should have ordered immediate shoring and investigation?

> What I'm curious about is why or how the column that was supposedly under the wall, punched through east of the wall?

Interesting question. You'd think, if the slab was failing from the east, the planters sitting on top of it would drop to the east as well, and end up east of that column, but that doesn't seem to have happened. That whole section of deck, to the next column line west, is all punched through, so did the deck hinge from that western extent of the break and pull the planters west of the column?

I still don't think this can have been the first part to visibly collapse into the garage though because it's quite close to the garage level elevator entrance, surely those people that parked up last in the garage would have seen it. They got into that lift only a few seconds before the main deck collapse.

" pull the planters west of the column" Is that the top course of the CMU wall lying in a line to the east of the column? If so it might be telling how far away it fell.

Edit: as well as the angle. It's further away near the trash can. So then the deck was hinged north to south when it landed. It fell further toward the south. Does that make any sense? probably not. The missing part would be that it slid down the slope further on the lower end. so the the deck would have to be angled down towards the s-e. I think.

edit2: scratch that. the effect of falling over the car lump probably pushed it out further on that end. I mean if that is actually the top layer of the wall, which it mostly has to be. I would like to know why it did not break into more pieces though.

once more: well maybe the top of that wall is a lintel. obviously.

Ok this is the last one: Forget all that. That is likely a column remnant from the tower. My apologies. Missing cmus are probably buried. I thought this was far enough away to not have a debris pile on top. Hard to believe the trash can is sitting there like nothing happened. There might, *might* be a piece of the planter cmu east of the trash can.

Quote (Red Corona)

I still don't think this can have been the first part to visibly collapse into the garage though because it's quite close to the garage level elevator entrance, surely those people that parked up last in the garage would have seen it. They got into that lift only a few seconds before the main deck collapse.

From a witness statement perspective, whatever fell first fell after the Vazquezes got into the elevator. They heard a very loud cracking sound while in the elevator lobby, just before they entered the elevator. They were within the elevator and going up to the lobby when the deck collapsed at ~1:15 AM.

Also from a witness statement perspective, all witnesses who described the deck collapse at ~1:15 AM describe it as a single big collapse rather than a series of two or more discrete collapse events.

If you’re thinking about the crashing sound at 1:10 AM, it may have been rebar breaking and not not concrete falling, as the Vazquezes did not report seeing anything fallen in the garage. However, we don’t know what space they parked in or what their path was from the parking space to the elevator lobby. So it’s conceivable that a chunk of ceiling fell down outside their line of sight.

Quote (RedCorona)

And while it might only be clear in retrospect that that puts the building at risk, surely a responsible engineer can see that that was already putting the pool deck (and therefore the garage) at risk, and should have ordered immediate shoring and investigation?

Yes, this makes sense. The situation appears to be quite complicated for an engineer and/or engineering group to be responsible for a structural integrity analysis. If a highly cautious approach is taken and nothing bad happened later, then you would probably get hammered as 'chicken little' by the residents/owners for inconveniencing them with all the shoring, cost and access closures and/or sued for harm due to potential reduction of property value and your competence would have been questioned. If a conservative approach is taken ( as appears for the Champlain Tower), working within the wiilingness and financial ability of the residents/owners and something does happen then your competence will be questioned. Certainly, many of those who could have affected the tower outcome have pondered many 'would have/ could have/should haves'.

At the risk of sounding like an idiot, I am just providing this screen capture from Penagwin from many threads ago.



Some evidence that the top course of cmu could stay together if the wall falls. This was said to be after hurricane Wilma. I assume the wall caps are responsible. I called them lintels for some strange reason.

There is also this capture from CE3527 from the same thread edit: note added by me.


Within his red circle of the column is the opposite side view of the line of concrete (resembling a column)and this angle looks like CMU. I hesitate to say it's the top of the planter wall, but.....

Thank you for your patience.

edit: second photo to add marks pointing to horizontal concrete section I am referencing. Forgot to add question mark. CMU (bottom opposite caps) apparent to the right of "planter column".

New Building Integrity video at youtube

https://m.youtube.com/watch?v=M0UtmbRAL9M

Sym P. le Josh of Building Integrity gives a very measured and clear explanation on the warning signs of punching shear that should have been recognised by an engineer/engineering firm involved with structural integrity evaluation. Very interesting observation on water flow on the column surface - I am going to start paying attention for this when I am in a parking garage type structure! A persuasive case can be made to question why was shoring not immediately recommended for installation to address the pool deck instability. This still appears to be a test case study/precedent study on failure propagation - only in hindsight is the threat to the tower recognized. Were the materials and techniques of construction at Surfside dramatically different than standards of the time? Maybe it has already been asked or stated in the many parts of this thread: Is there a risk to a whole generation/era of structures built in a similar manner?

Quote (Miami Herald)

The planter would be removed as part of the overall renovation plan just getting underway at the tower, he said.
Stewart said he remembered seeing some roots in the crack, but engineers consulted by the Herald say that wasn’t enough to determine the cause of the break definitively. “Part of these visits was to monitor the building, so if you see a significant change in something, that should be a red flag,” said Dawn Lehman, professor of engineering at the University of Washington and a consultant on the Herald’s collapse investigation. While it is possible that roots damaged the planter, it is not the only explanation for the gaping crack, nor even the most likely given the timeline and condition of the slab below, Lehman said

I'll play devils advocate here. The timing and location are very suspicious that this was a deeper problem related to the collapse. However correlation never implies causation. There is a nonzero possibility that the planter crack was just do to roots and nothing more.

Arguments for this being roots:
Roots were observed inside the crack.
A large part of the crack is vertical, hard to accomplish by deck sagging.

Arguments against roots:
The location is very near the heavily loaded part of the deck
The timing is right before the collapse
It appeared suddenly
These type of major cracks were not seen in other planter boxes (As far as I've heard)

Quote (Brian Malone (Industrial) 16 May 22 18:03)

Is there a risk to a whole generation/era of structures built in a similar manner?

Perhaps from certain builders.

Roots add extra material, you can create cracks by root infiltration and growth but you'd expect them to push the structure up and out, not down. I can't see any way in which the planter being lower than it originally was could be caused by roots.

Edit: watched the BI video now, and he also addresses this, and points out that you'd also expect a much slower crack growth and water/organic staining if cracks were caused by roots.

You can actually see (and probably measure) the amount by which that slab is not planar from the pics, as well.
Edit 2: and you could do that from the 2020 picture, too - which shows a significant depression already, not sure if that was designed or if it shows flexure already a year before - and compare

Quote (Sym P. le (Mechanical))

... is indeed a column, 75 to be exact.

I may have failed in the ambiguous nature of copying the original photo from a prior thread in which column 75 was already circled and the actual subject. I'm talking about the horizontally laying column-like feature that is about 6-7 feet of so to the right of 75 in the photo I provided. The reason I used that photo (other than convenience) is from that angle you see the opposite side of the feature which appears to show the hollow structure of cmu's. As far as I have known from the beginning 75 is not lying horizontally on what remains of the deck. So I am not talking about 75. In Reverse Bias photo the feature stretches left-right in the foreground in front of 75. It was once speculated to be a column that fell from the tower. There are such columns to be seen. But that was from a much further view point from above. If it's a matter of enlarging the photo to focus more on what I am talking about I can do that.

I see. You make a good point as it confirms that the upper portion of the planter wall is reinforced cmu's

Sym P. le now that I have watched the BI video you linked, do I understand your post from 15 May 22 21:16. The pool of water at the base of column 76 is clearly there. To those not aware of the signs of failure this just looks like a damp column!

It's possible that as the 76/slab connection deteriorates, the low point of the deck shifts to the north.

When I look at the picture of the crack, I don't see any crack in the deck. It seems if the section on the left (in the photo) dropped, there would have been a crack in the deck, too. If you argue that the whole deck dropped down (along with that section of the planter), thus eliminating a crack in that area, what caused to top of the planter wall to refuse to drop with everything else? That isn't just a horizontal crack, that's an opening of about an inch.

How can the deck and part of the planter fall downwards, but leave the upper part of that planter wall behind?


spsalso

The structural slab is buried in a topping layer (varying thickness to provide slope and drainage at time of placement) and deck tile. This will redistribute and disguise structural deficiencies in the slab (as seen from above).

It appears that there is a course of cmu's capped by concrete, or the upper layers of cmu's have longitudinal reinforcement. Either way, it's obvious that it has longitudinal rigidity that spans high/low points in the deck deflections. Apparently, the reinforcement did not extend around the corner.

edit: Longitudinal reinforcement may have been required so that the planter contents don't push out the walls.

I would like to understand more fully the crack progression mapped by IanCA, married up with Sym P. le's overlay animation.

EDIT: I am not implying anything right or wrong about IanCA's theoretical sequence, rather would like this crack layout information added to Sym P le's animation.

Edit 2: If you look at Green/Yellow/Red Sag Diagram posted by Reversebias, clearly there is a large area of red sagged area along the South Wall after corrosion factored in. The only way I can see that much sag at the south wall is if the concrete/rebar has sheared from the wall connection in that area which would shift stresses to the South, East and West.

Edit 3: Or the foundation supporting the south wall had settled in relation to the interior columns.

"The structural slab is buried in a topping layer (varying thickness to provide slope and drainage at time of placement) and deck tile. This will redistribute and disguise structural deficiencies in the slab (as seen from above).

OK. So the slab drops, but somehow leaves the decking in position (leaving a void)--there seems to be no damage to the decking (see, for example, the "area detail" shot that shows the joints between the two walls and the decking). But the wall on the left is still neatly connect to that decking, as is the bottom of the wall on the right. So that would imply it stayed with the decking instead of dropping with the slab. But then the upper part of the wall on the right would somehow have to have raised itself up an inch to make the crack.

It appears that there is a course of cmu's capped by concrete, or the upper layers of cmu's have longitudinal reinforcement. Either way, it's obvious that it has longitudinal rigidity that spans high/low points in the deck deflections. Apparently, the reinforcement did not extend around the corner.

We don't see evidence of any deck deflections. It all looks nice and neat-ish, and pretty well connected to the bottoms of the two walls.

edit: Longitudinal reinforcement may have been required so that the planter contents don't push out the walls.

And that needed reinforcement would have been in the horizontal plane, not the vertical."



spsalso

In light of the new evidence recently presented, if I was the engineer and had requested pictures of the cracked planter box, I would have also wanted to get pictures from the opposite side of the planter box as well as from down below. Was there any damage to the side of this planter box facing the parking area? Does the lack of expected pictures imply a lack of damage or a lack of concern?

Was the planter box fractured by the column breaking an inch through the concrete slab and into the CMU but being held and supported by the rebar alone at that time? If that is the case, then it makes some sense that the planter box may not have fractured on the side facing the parking area so no need for photos. That could also mean that more catenary forces were being applied to the deck for a longer time period than what we have been thinking.

Quote (spsalso (Electrical) 17 May 22 00:27)

Good stucco with elastomeric coating? eg: BEHR PREMIUM® Elastomeric Masonry, Stucco & Brick Paint No. 68

The upper corner flap is a good example of quality product ;')

Quote (Nukeman948 (Electrical) 17 May 22 00:50)

... the column breaking an inch through the concrete slab and into the CMU ...

The column is not doing a stabbing movement. It's the slab falling down around the column "as though it was punched". The planter merely remains in place atop the column/slab shim until it looses any semblance of stability as the wider remaining structure drops out from under it. The slab section south of the column is showing greater downward movement which would be consistent with failure of the slab/column connection being initiated at the south edge of the column where the stress is greater from the 30' span.

Quote (spsalso (Electrical) 17 May 22 00:27)

The displacement in the corner of the planter is not representative of the movement everywhere else. I would read that corner as an indicator of displacement but would exercise caution on what it means. The upper corner of the planter wall being perpendicular to the structural member of interest would exaggerate any gaps due to slope changes in the slab. The vertical drop on the south side of the column is very real and and given the columns proximity to the corner (which is a low traffic area) the aggregate of all the materials may just be floating over a discontinuity in the slab and waiting for a good thump.

Regarding planter wall reinforcement, although a primary benefit in this case may be for horizontal reinforcement, a simple lintel reinforcement scheme would benefit in both directions.

Really, I don't have all the answers, I just hope I'm right enough to be able to defend my posts. Thanks for the feedback.

Quote (Reverse_Bias (Electrical) 15 May 22 23:19)

I've made more than a few posts debunking the Miami Herald's analysis. For instance, the graphic you posted starts with edge conditions which include the slab along the south perimeter dropping 1" in an undamaged state. That just doesn't make any sense. That's not to say that punch out doesn't happen, it's just that their graphics are way off. A better analysis would have been to examine progression given slab punch out at the most stressed column/slab connections, which are easily determined, and the results would have been more interesting in areas they highlighted. I think the Miami Herald was trying to sensationalize the impact on CTS of the work on the neighbouring property and as a result did the discussion a disservice.

I was still trying to pull all the pieces together... I'll show the Extrema Tight Crop first, but I'll attach the original AP photo.

SF Charlie
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• https://files.engineering.com/getfile.aspx?folder=6058a25b-df94-4181-943f-b

Looking at the crack in the planter situation:

The slab drops.

What does it take with it?

It can't be the "return" wall (the one on the left of the picture), because the slab would have pulled it through the decking (which, it has been argued, separated from the slab), and there would have been a crack between the decking and that wall.

It can't be the bottom of the long wall, because there also was not crack generated when that part was pulled past the decking. The detail photo shows the two walls meeting at the deck, without any apparent damage at all.

That leaves us with a slab that fell, leaving the decking and those two parts of the wall in place. AND the top part of the right wall, which decided to jump upwards. By about an inch. Because it was in the mood?

I do believe that is a correct description. Am I missing something?


spsalso

Quote (SFCharlie (Computer) 17 May 22 03:22)

I had to download the file before I realized what it was you were getting at --> Column_came_though_planter_box_AP_Building_Collapse_Miami.jpg

As I stated earlier, the column didn't go through anything, everything else fell down around the column.

Perhaps they should rename this failure mode "falldown" as opposed to "punchout" but that would just confuse everything else.

Quote (spsalso (Electrical) 17 May 22 03:32)

Possibly, there is differential movement between components that the imagery isn't tuned to convey. We don't know the time stamps (day?) on the various images either.

Oh G. Just when you thought we could all get through this without grainy photos of objects being IDed in powerPointy...

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Quote (Sym P. le (Mechanical)17 May 22 03:33)

... everything else fell down around the column.

Yes, ...got your point

SF Charlie
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Quote (thermobaric (Military) 16 May 22 22:24)

Though I don't see the point, I tried to do an overlay but just seemed to make a mess. You are welcome to mark up my images and show your results.

I'm just thinking with this new imagery, it's like interviewing Moses after crossing the Red Sea and not mentioning that the sea parted.

Moses: "We just did it"

Reporter: "And you're not even wet!"

Moses: shrug

Quote (Sym P. Le)

It appears that there is a course of cmu's capped by concrete, or the upper layers of cmu's have longitudinal reinforcement. Either way, it's obvious that it has longitudinal rigidity that spans high/low points in the deck deflections. Apparently, the reinforcement did not extend around the corner.

I think you are correct Sym P. Le. Here is a sectional elevation of the planter from the 1979 drawing set, showing an 8x8" concrete cap with 2 x #5 bars:



I think that detail was drawn with the southern wall in mind, but I imagine it was applied to other planters and explains the longitudinal rigidity you describe.

So. From the photo of the cracked area of the planter, it appears the slab, deck, and parts of the planter dropped about one inch. The upper part of the wall on the right did not drop, probably because it was held up by the concrete cap--that being held up as a cantilever from a section that didn't drop.

I am wondering why the top of the column underneath isn't sticking out of the deck an inch. If there was a "buncha" sand between the deck surface and the slab, it could have absorbed the displacement. I suppose.

And all this happened a few days before June 8.

Since the slab and etc. dropped down over the supporting column, there should have been signs of that in the garage. But no one reported such a thing, it appears.


spsalso

Quote (SFCharlie 17 May 22 03:52)

Thank you my power-pointy hero. At least you understand that the planter box has an East wall and a West wall at this section and that if the box had been positioned so that it's walls straddled the column then we would have likely never seen any damage from the relative motion of the column and slab moving in the vertical plane.

I have the distinct impression that there is more info available that we are not privy to about the state of decay that was not acted upon. A 1 billion dollar settlement didn't just fall out of the sky either.

This should give folks pause for concern and at the same time relief. Their buildings won't just fall down, however ...

Is this the sort of damage that could have been caused by a tar buggy that fell sometime prior to the collapse? I kid…

But looking at the planter pictures, imagine if it wasn’t the column under the planter that was punching out. But the column to the left
of that area. Wouldn’t the bending moment in that wall at the planter column cause that long longitudinal crack that is formed there?

Essentially popping the top of the wall up an inch as someone else above postulated. When the vertical joint in the corner of the planter failed, that seems like what the top of the wall would do if it were being subjected to bending restrained by the column beneath.

If I had seen that damaged planter box, I probably would have thought:

"Oh, look. This whole damn building is just falling apart. Sure does need work!"

instead of:

"Oh, look. This building is FALLING APART!!!!!"

That's likely because I see a lot of buildings "falling apart", but very few (if any) "FALLING APART".


So I have some sympathy for someone thinking it was root damage.



spsalso

My thinking is the CTS building side of planter column held after initial drop on 87 Park side. Looking at amount of cracks in parking deck west side of planter column indicates the most decayed slab is in parking deck direction. Which points back to pool chemical exhaust in planter at 87 Park perimeter wall.

Column 76 is likely a low point of slab and as such was drain relief point for slab, before planter column failed. I don’t see much rust at column 76, rather I see more white chemically changed concrete. Therefore steel is perhaps only thing prevented punch.

Is planter drop due to slab sag or a shear crack opening up?

Lots of cracks radiating South and west from planter.

Edit1: I concur with Spartan5’s comment and point out this is in line with IanCA’s earlier posts.

Edit2: Live load cycling on deck is a factor and no waterproofing under parking deck

Edit3: Could it be I14.1 that punched first? I believe that was one of IanCA’s theories?

Edit4: How does a delaminated deck affect water drainage and variations between what is happening on top and bottom of slab? Could delaminated deck cause water drainage at column 76, on what was originally a flat deck?

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It looks to me like the long horizontal crack might be more superficial that it appears. As in it might be more lateral movement (maybe from the forces of root growth or the weight of the contents) and there is a shadow being cast to make it look larger. if you project it to the most northern point in the phot there looks to be prior patchwork at the point it emanates from. So this could be the expression of a much older condition. I'm not saying the crack was this pronounced prior to the southern portion dropping. It might have been disguised by the elastomer coating, not needing a patch yet, and just made itself known when the deck dropped. Thoughts?

Quote (zebraso (Mechanical) 17 May 22 17:44)

There's no sugar coating that crack

Quote (SFCharlie (Computer) 17 May 22 15:57)

I was thinking along the same lines. The slab didn't need to drop from its perch, braking its back creates some interesting differetials. This also has implications in puddle depth and drainage around a puddles perimeter.

Cetainly within the frame of the closeup. But if you are looking for a reason why the longitudinal strength of the caps was so effective then if the long crack is not the 1/2" plus gap for much further than the corner, then it makes more sense. i.e. there is not 10 feet of wall suspended in air. Or more to the point, there never was. So I/m trying to see if there is another vertical shear back from the corner north, but there is not enough photo detail in the long view. From the long view it look like the crack goes close to zero 3-4 feet from the corner.

Could the crack have been in slab under that area, thus having most effect on 87 Park side of Planter column?

Seriously, the planter wall has an upper and lower part, the upper part having a greater stiffness than the lower. The lower part moves with the sagging floor while the upper part remains stiff as a beam supported on the column (south) and the slab (north) which we may, for the sake of argument, presume doesn't move much as it is close to the next column to the north. The portion of planter which breaks away south of the planter column (75) sits solely on a portion of slab which is presumed to sag and/or alter it's form due to degradation.

An inch or more of separation is breathtaking but it doesn't defy basic physics.

Quote (Sym P. le (Mechanical))

Seriously..... (drawing)

You're awesome.

Just saying cracks could be located where 'Grey' arrows are on the toddler diagram, which is the longer span side of column, thus primarily affecting one side more than the other?

yes. next lesson "coloring within the lines"

Actually, I like the drawing by Sym P. le (Mechanical) 17 May 22 18:54 better than power pointy...
It's when engineers start sketching on the backs of restaurant placemats that breakthroughs are made...

SF Charlie
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Speaking of powerPointy, I was making a very involved slide of the April 2020-June 2021 photo (that I didn't learn much from),
when I started to wonder "why was the April 2020 photo taken?"

SF Charlie
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We need a 3d drawing cause the planter appears to be leaning east towards the pool also.

Quote (SFCharlie (Computer))

why was the April 2020 photo taken?

Unless it was cropped, the subject seems to be "cleanup time". You've got the broom, dust pan, and garbage can. I might have taken that if I had to buy more trash bins and had to make sure I got the model. But seriously, it's a good question. It's a bit bothersome.

Add: anyone look at meta data on these files to see if the cameras are the same camera? Does that get stripped when posting? does png have meta data? It would be interesting if the same person took both (as in the engineer).

Yes, that planter (in the June '21 pic) has definitely fallen down to the south and east, not just south. Most likely interpretation for me is that the punchout is beginning to happen around column 76 (that's I14.1 right?), not so much around the one under that planter, and it progressed to actual collapse when the effects of that punchout overloaded the one under the planter as well and caused it to punch through too.

Your PowerPoint arrow interpretation looks fair to me, in which case that part of the slab and planter dropped pretty much straight down. The idea that it moved west is probably an illusion of the photo from the other side.

If the collapse did initiate on the deck, and that looks pretty likely with this new information, it's still worrying that the night before there were noises within the building as well. That implies that the whole thing was badly built and in trouble, not just a single flaw - and how many other buildings of a similar age might be like that too?

> why was the April 2020 photo taken?

An interesting question in itself, particularly as it looks like there's already significant deflection there to me.

I don't get it. Alarming, sudden appearance of deterioration, therefore look somewhere else? Logic?

Even though I know I can not 'add value' to a SymPle GIF, I thought I would try, while we wait on SF's PowerPointy.

What I am trying to show is correct column labels on some of the columns of current interest, and that the center line of the slab running under the planter 1" drop aligns with Column I14. And Not I14.1 as I incorrectly stated earlier, and that Column 76 is L13.1, unless I made boo-boo, as I have not received the "color between the lines" class yet.......

And all that displayed on the Outstanding GIF, I just plagiarized.

I am wondering how the planter wall reinforced top made it over the trash can without wiping it out. Then I am imaging it was held up for a time by the column. It looks like the piece of wall top that would have smashed the trash can is rotated 90 degrees. Perhaps that portion was hanging down when it fell from the column. Not that it has any bearing on anything. Just trying to make sense where there is none.

Is there an east-west construction join that runs through the corner of the plant where it cracked? It looks to me like there is a demarcation in the fallen deck where the deck south of that line is higher and maybe even resting on the north section. I thought all the construction joints were N-S. I don't know how you would explain them overlapping, so maybe they aren't. But the south seems to be resting higher along that line. I see this without playing with pixels.

Edit: suggested in this photo (tight crop from a WSJ photo previously posted)


Note the garbage can for perspective. pavers and deck south of can relatively planar and undisturbed. Trash can sits at a level a step below. Pavers north of this line are disarranged and deck is desk DIS- continuous. Does it mean anything? Don't know. There is tower debris encroaching from the lower left. did the falling debris cause this fracture to propagate? All an illusion? Time for my pills now.

The image is so blurry I can not make out the garbage can. I went to WSJ, and grabbed the image below. Is the first image, the WSJ photo you perhaps took a screen shot of? Your thoughts are interesting, but I am still processing.....

Clearly in the second image below, now that I have high resolution from WSJ, I can see the diagonal break in parking deck that is either radiating towards the trash can and dropped planter, or radiating from?






Did anyone else notice that the planters were to be water proofed in 1979, however "weep holes in planters where practical" ? In detail posted by IanCA.

GREAT way to keep that structural slab soaked around the planters...

that's it. I didn't modify the pixels. I just enlarged the image and cropped off what was not of interest. Now if simply saving a png format image readjusts it, I don't know. There are areas (more than one) of fallen deck that are essentially quite "planar", with the exception of localized punch points and the major trough there in the middle. The line I drew is where there appears a more significant break from any hint of planarity. Debris from the fallen building does not help to decipher it. You can see the angle of the sun better in the full WSJ image to see where shadows would be. When I said I could see this line without adjusting pixels I was looking at SFCharlie's AP images several posts back in this thread. I just think this image was more useful because it's more oblique to the deck even though it's quite grainy at this level. The date of the WSJ photo would help but from what I can see things are in the same state. A side by side comparison would help also.

Edit: About the second image with diagonal break. I realize that was identified as significant by several posters recently. I guess the question is whether that is what is propagating all the way out and near column 76. That's the gist of what I am trying to ascertain.

edit again: Weep holes. I saw that. Where practical? That must be with foresight of the drains clogging after a month of use. Actually not too bad of an idea if the deck would be adequately sloped. And that turned out not to be the case. Are the drains bigger than a weep hole for long?

Do you expect a problem with weep holes that drain from a potentially waterlogged planter onto an exterior deck that is, on occasion, afflicted with rainwater?

I suppose you might if you assume incompetent construction methods. But then, the AHJ would catch that, and require correction. Which, of course, the City of Surfside did.

Or not.


spsalso

Gotta find every satellite photo available to see if the wet spot on the deck expanded towards 76. It's a mystery how a column head got to be the low spot. A mound should form above the column during the punch shear process, hence the leaks should be between columns or at least a few feet away from them. Also the slab directly over 76 also could not have dropped far without popping out the pavers above it.

Maybe there was some odd internal voids within the slab causing this? It almost points back to the delamination theory.

>It almost points back to the delamination theory.

Sure seems like it. Eye witness testimony of water poring into sunken deck. Voids filled with water that pours out when the deck falls. Josh described 76 as covered with efflorescence and water very wet (from the photo he was shown by MH). for the water to contain that much dissolved mineral content it seems like it might be continuously wetting concrete. When he said that I was thinking the water is not just running in around the top of the slab straight down around the column whenever it rains. Just a brief thought. But now you made me recall it.

Edited for dumb stuff.

Quote (zebraso)

for the water to contain that much dissolved mineral content

Perhaps the runoff from the planters was more acidic than usual. If the salt and chlorine ion levels were higher?

Well that's a chemistry question. My head hurts as it is. The reactions involved were discussed earlier in this thread or the prior one. Not sure but acid from the planters (due to decay of organic matter or whatever is going on in the soil) would accelerate whatever is going on with the chlorides in the concrete dissolution. Some of the chemistry was posted previously. But whether it's carbonic acid or some other acid I don't think it matters. but between salt and organic planter decay in this environment I would guess the salt is a much larger factor. Unless those are acid loving plants and they are dumping it in. Wouldn't that be something? interesting question. Let's dump Miracle Grow Acid into the equation.

On an unrelated topic, MDFR Deputy Fire Chief Jadallah conducted an investigation to determine the identity of the woman whose voice was heard in the garage. He has concluded it was that of the Live Nation Executive Theresa Velazquez, who had been visiting her parents in 304, rather than that of Valeria Barth from 204 as reported in USA Today. The report, which mentions spontaneous fires from EVs as previously discussed here, counters the USA Today claims that MDFR caused the garage fire and that the victim’s corpse was incinerated.

Here is the PDF of his report as provided by the local NBC affiliate in this story. The links within it don’t seem to work, but the embedded photos are there.

https://s3.documentcloud.org/documents/22017784/su...

I will update the spreadsheet, which lists the initial survivors of the collapse. Having occurred after the collapse, though, this has no effect on the timeline leading up to the collapse.

Perhaps someone could do a drawing showing how the previous epoxy filled cracks in the low parts of slab that were leaking water, caused a larger water head to build after rain in the areas of the deflected slab. Say max deflection of slab is 3" at mid span, and with 9.5" slab, that means there is approximately 6" of potential water head in the structural slab, assuming .5" slope, for water to travel to crack at column.

I tried a toddler diagram but I could not keep the coloring between the lines.......

Clearly the water intrusion from planters was degrading concrete faster in deflected areas of slab, which is probably where epoxy injection was first performed to keep water out of garage, but creating a sorta artesian well effect around column 76?

Edit: But never emptying fully, thus leaving lots of water sitting in low area. So the top draining of water pond, lets sediments to fall to bottom of depression

Quote (zebraso)

I would guess the salt is a much larger factor

Agreed, but don't forget the exhaust from the pool equipment room...

Quote (thermobaric)

"weep holes in planters where practical"

My concern with that statement is the uncertainty. To quote Jeff Ostroff "If you don't tell the water exactly which route to take, it will take the most expensive".

Agree, constant pool of water and salts and chlorine from pool exhaust, leading to failure of slab at low points.

Quote (zebraso (Mechanical)18 May 22 02:45)

I appreciated your photo because it was from a different angle. together they could give us 3d info.
Please remember the cars under the deck supporting it in odd ways.

SF Charlie
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Quote (IanCA (Mechanical)18 May 22 06:36)

Perhaps the runoff from the planters was more acidic than usual.

Please remember that 76 is not under the planters

SF Charlie
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I overlaid the displacement and cracks graphics from the Miami Herald. Cracks from the central puddle are leading to 4 different columns, including 76. Assuming the cracks somewhat resemble what is shown, the water would have a potential path.

Excellent work, Reversebias.

Interesting to note the linear E-W crack in bottom of midspan depression, that lines up parallel between the column lines, thus the planar crack line that Zebraso was seeing in his Pixelizations......

The Planter roots could have made their own path for the water in the depression also...... after they clogged the drain lines in planters....

I don't remember seeing this, but then I do not subscribe to MH.




https://www.miamiherald.com/news/special-reports/s...

In the "with corrosion" image, What's that in the north west corner? Isn't that one of the early failure locations as seen the collapse video?

SF Charlie
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Could be, I have slept many times since then..........., meaning I have forgotten, and need to watch video again to see what you mean.

With the flurry of news going on this week, did any of you notice that the City Of Surfside decided to kick in $2 Million also? I don't think they are named as a defendant in any lawsuit, but they wanted to do it and confirmed the vote the other day in a rare Monday morning vote

Any updates on the other sister towers and if shoring is still there or what's been going on? When I was in Miami a couple weeks ago I really wanted to visit the sites, but figured it'd be a waste of time since I wouldn't be able to get in anywhere.

Again, the MH graphics are not worth the ink or pixels. They start with a premise that did not exist and continue down that rabbit hole on a lark that the neighbour brought down the tower.

Quote (Miami Herald)

Morabito and his team inspected Champlain South frequently between 2018 and 2021, taking photographs and writing nearly half a dozen reports noting the pool deck slab was in urgent need of repair.

Do we have all of those reports and supporting material?

I agree MH modeling may be off base with their Assumptions, as they don't reflect 'As Builts'.

However, I find it very interesting that the 'As Designed' Model shows cracks in the areas of interest that seem to align very well with the current evidence we have, except for South Wall (which I have hard time believing we have the deflections in red they show along the wall, with it still standing?

So yes take it with a grain of Salt, but I don't think you throw the whole thing out either at this point.

Actually, it is better to throw out their model. MH can update their model to help folks understand how this building fell down and why theirs won't. Regarding vibrations from the neighbour, it is possible that it impacted Champlain Towers but it didn't cause CTS to be constructed in a way that it wasn't or lend credence to machinations that a concrete slab, regardless of reinforcing, has less strength than who knows what when continuously supported by a concrete wall. The complex stress patterns developed in a two way slab with a variety of support and stiffening elements are better visualized with a proper digital model than imagined.

Structural Madness's model, though also imperfect, lends better insight to this collapse. Note how the deflection across the 30' span creates a high stress zone along the south edge of the 13.1 columns and north edge of the 14.1 columns. This is consistent with the evidence seen regarding the planter and column 76.

Agree with you again, as I just thought of the water loading on top of the deflected slabs, and how much more load that added beyond any design calculations for dead weight and 'standard' live loads of so many PSF.

I guess what intrigued me was the linear crack in line E-W with Column I, which was NOT mid span.

Edit: I Yield! You are right! Yes Vibrations add a whole other complexity, even different from parking deck cycling.

With an inch or so of sand under those large pavers on the pool deck, neither of which were in the original design model, they were added in 1996, I showed on one of my July videos how the sand layer beneath the pool deck can obviously retain a lot of water weight. Even days later after rain, it still would be moist with some water, adding a lot of weight at 8 pounds per gallon.

Every time it rains the dynamic weight load goes up and every time it dries the weight load goes back down. Seems to me like the slow-motion bouncing of a trampoline.

I wonder if during a rain event, the 30' span had enough advantage to pull the other bays tight, thus amplifying its ability to collect even more water? Or in other words all the storm water made its way to the 30' span.

Episode 11 of the Miami Herald’s podcast talks about the planters.

Interesting thought about water load on 30 foot span, and I would think so, and when it dried or leaked thru garage, it would have shifted the balance some the other way, which would appear to induce even more stress and cracking.

I also wonder if the E-W rebar was actually the final straw that broke the camel's back. Specifically the drop of the planter could have been the E-W rebar loosing it's grip at Column I14 connection. Once it lost grip, the other columns were already in partial punch and ready to go.

About episode 11 (MH podcast) The narrator says part of the number 76 on the column has been "smeared off". I imagine that is in the sense of washed away or something. No. It is partially covered with efflorescence deposited by supersaturated water trailing down. The calcium carbonate just happens to be the same color as the white paint. What is on that number is the dissolved skeleton of the structure.

No. It's deceptive seeing that long east/west alley but that's not how to analyze it. If you check the larger graphic on the video, you will see that the gradient is not as steep at the west end, therefore less strain. The 30' span is doing the heavy lifting with a particular stress point at the column edge.

Edit: I may have spoken to soon. The column you are looking at is misplaced in the model so it doesn't reflect CTS exactly but the results as presented are interesting.

"With the flurry of news going on this week, did any of you notice that the City Of Surfside decided to kick in $2 Million also? I don't think they are named as a defendant in any lawsuit, but they wanted to do it and confirmed the vote the other day in a rare Monday morning vote"

Of course not. Their Building Department appears to have done something close to nothing in ensuring that this building was properly built, but also accepted $40,000 in permit fees to ensure that it WAS. It just MIGHT be a little short, dollarwise. And then there's criminal negligence:

If you accept money to do a job (inspect a building during construction), and you don't do the job (by delegating the PE to inspect his own work), and people die because there were flagrant construction errors, does that not sound like criminal negligence?

I could be in error here in my assumptions, so please correct me if I am wrong.


spsalso

Thanks stcbus.

Quote (MaudSTL)

Episode 11 of the Miami Herald’s podcast talks about the planters.

Thanks MaudSTL.


The statement that concerned me in podcast Episode 11 was this at 17:50: "This exact same area had been photographed a little over a year before, in April 2020, and in those pictures, there is no sign of the cracks, at all."

But when I zoom in on the April 2020 photo, there certainly looks like some signs of prior damage to me.



And I think the area that Josh described as 'blurry' needs further study to understand why the horizontal crack is not clear in that area. It doesn't look like any of the usual optical or digital artifacts. Perhaps it was another area with prior repairs?

I did not notice this localized sinking of planter area only, until this posting of the previous bondo repairs was pointed out. The whole area of planter has dropped like into a sink hole (for lack of better analogy).

So I will ask, could we have dissolved rebar grid in this area, which just happens to line up with column Line I14? We know we have a diagonal crack headed to this area from the parking deck.

So loss of a square of rebar grid/concrete failure in this area, could lead at first to localized drop.

Loss of grid in this area, would appear to start transferring load to surrounding columns. Which in this case are K13.1, K15, and I14. Which breaks the rebar tight rope in this area, and now 1-3 columns at once loose what little punch shear resistance rebar they had on at least one side of each column,

Boom!

SF Charlie
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SF Charlie
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“Catenary Stubs’. Got Love ❤️ It!

SFC, Outstanding Power Pointy! Now to digest

Here is the powerPointy

SF Charlie
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• https://files.engineering.com/getfile.aspx?folder=8a1624d9-dd40-4d1e-8747-c

"Over the years" Five Years? I mean, the gravel of the 5 year old "walk" is flowing out where the anchor was? Maybe they trip-hammered the bottom of the CTS perimeter wall, when they trip-hammered the pavement (sidewalk?)? I've had a curb broken when the adjacent pavement was removed.

SF Charlie
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So in the April 2020 photo, I see a pretty radical dip in the pathway coming out from between the two planters, and going left.

In the June 2021, it appears to be much less of a dip.

I am basing this on the helpful color lines overlaid onto the photos.

I wonder why that is.


spsalso

I may have missed it, has anyone suggested the directly that the April 2012 photo may have been taken to document slumping. The building manager has stated that near daily walk-arounds were done for the purpose of property safety. Let's give him a lot of credit for that much. He may have noticed the beginning of movement as early as April. What if we find out there were more photos of the same spot taken even earlier? I mean this is not a tourist photo that was handed to NIST when they requested them.

Edit: belaymylast 2020 not 2012

This thread is approaching 400 replies. You might want to start Part 17.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

Reference Fuchsia Arrows on SFC's Power Point Graphic.

As mentioned earlier, would failure at South Wall Under Planters actually cause the 'Catenary Stub Area' to initially move upward, until things let go? Basically the South Wall to Column K15 becomes a bigger lever arm load on the span between K15 and K13.1 for 2 weeks and 2 days?

Edit: Middle Span is 30 feet and much longer than adjacent spans, which begs the question, how in the world do you design a flat slab with same rebar everywhere and same slab thickness when spans are not equal? Looks like it was designed in that 30 foot span would deflect more than adjacent spans, thus providing 40 years worth of unbalanced stress on pool deck? Not to mention the various column sizes and layouts?



On the next two images below, are we seeing evidence of slab drop at South Wall? Note Dark base board like area at wall/patio deck joint?

Quote (thermobaric (Military)19 May 22 17:11)

Good Questions!
please see the following from Josh (building integrity):
1. Engineering Failures Found in the Champlain Towers South Drawings - Surfside Collapse
(Toward the end, where he talks about the changes in the area of the valet parking planters)

2. Zeroing in on the Initiation of the Surfside Collapse

3. 16 Days Before the Surfside Collapse - The Warning Signs Were There

Thanks.


SF Charlie
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Elevation survey 08/07/2020

• https://files.engineering.com/getfile.aspx?folder=02ea9002-b5fa-46a9-a199-4

Thanks SFCharlie for those BI links. I watched parts of them again, and this time it sunk in better, I think.....

I added where roughly Column 76 is, and lowest point near that column from Survey Posted. This clearly shows why Column 76 was such a good drain path for deck, after perhaps the nearby cracks were epoxy injected.

Edit: Also shows 9.52 low spot on parking deck side of gate from pool deck, with 9.5 drain elevation nearby.

Edit2: I do find it interesting that Building Integrity has NOT linked the Pool Exhaust Fan Exhaust venting East along South Wall, as a probably contributor of accelerated corrosion and slab shear in that area of south wall. I did notice in BI's links provided by SFC, that on one of the original drawings he uses, the exhaust fan originally exited on the West Site of Planter Wall at South Wall, and not East as built.

Here is my first attempt to visualize the elevations.
As you can see, trying to draw contours was a disaster.

SF Charlie
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The deck had much less variations in height 8/7/20 than say April 2020 Photo or June 2021 Photo. Per survey only about a 3/10 variation form high to low. Which is pretty good considering the two layers of pavers and sand fill. Problem is Finished Deck heights do NOT necessarily tell the exact story of the structural deck.

Next Try, Feedback Please

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It helps me visualize the elevation differences well, much like a contour map would. In some ways it is better to me.

Edit I assume the elevations in the planters is at bottom of planter, which indicates that there may be a layer or concrete forming bottom of planters that is on top of structural slab. Or some sort of elevated base inside the planter, perhaps part of a drain system, or maybe just the dirt level in planters.... Duh!!

If I did not know any different it looks like they were directing water from the entire pool deck to go through the gate and onto the non water proofed parking deck. Then maybe it was supposed to go to the street. I mean assume a drenching rain down pour in which the drains are overwhelmed. Is this the proper way to do it?

Moribato may have had his faults, but he did identify failure to provide slope in the pool deck as a major issue and indicated fixing it in his proposal.

SF Charlie
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photo I saw of the pool and deck taken 36 hours before the collapse clearly shows a proper slope to me so I was always puzzled by Morabito's comment that there was no slope.

Structural deck vs pavers (maybe). This was just pointed out.

What is the effect of directing water to a central point where the structural deck underneath is not sloped? Is that a "special" problem?

Zebraso, it's a bit confusing actually. The deck below might be sloped, and the pavers are also sloped so everything is OK. OR, the deck below might be flat and unsloped when the pavers up top made up for it by sloping the sand layer to create that 1/4" per foot slope.

But Morabito stated in his report the architect had a flaw in his design, of no slope. That is false because the floorplan clearly shows the slope in the 1979 drawings on that pool deck That is what I was puzzled about why he stated the architect scared that up when the drawings clearly show the slop in it. So we will never really know. Morabito provided no photos showing a flat spirit level on the actual as-built pool deck slab, to confirm his claim.

Things that make you go HMMMM. How many places has it been reported and repeated that the level deck is one of the original sins in the as built.

Edit: it's a bit unclear to be now whether the claim was that the structural deck has no slope or is insufficiently sloped as built. I'm not sure it matters. I mean the deck as constituted by the cores that were taken.

Quote (Jeff Ostroff (Electrical)20 May 22 00:40)

I don't know when the elevations were taken, or what the units are, but I assumed (Yes, we know what that makes you and me) inches. that would be only 9.8 to 9.5 = 0.3 inches slope across the whole pool deck?

If you look at any of the drawings of the pool deck area, you'll see the deck field drains are about 20 feet from the pool, so we need 1/4" x 20 feet, which is a 5" slope from the pool down to the drain.

Also, if there is lippage between the pavers, that could inhibit the downward water flow. One of the great ideas Morabito had was to add grout between the pavers. This would, in my opinion, help reduce the amount of water going down between the pavers, as the grout provides a smooth pathway down to the drains for the water to run down.

BTW I am working on a new video covering some of this, and other item, the settlement, the lost first responder audio files, and some new theories I have on what could have caused the planter to crack in the Miami Herald photos

Since I have been throwing around the term "structural deck" without reviewing the core samples I have revisit my characterizations.
Looking at the report on the cores I can see they have identified the structural slab, topping slab, tile and mortar layer (sloped), water proofing, sand and paver. Apparently the sand and paver are not actually in the core sample as shown even though they they are listed.
So I think what I should have said is structural deck, topping, tile and mortar, for the original slope - or what was under the water proofing.

Quote (SFCharlie (Computer)20 May 22 01:46)

... when the elevations were taken, or want the units are, ...

The drawing is from Morabito's package for remediation. A note on the drawing states the elevation survey was conducted on 08/07/2020. Units are decimal feet as far as I can tell.

Quote (Sym P. le (Mechanical)20 May 22 02:54)

decimal feet

Thanks. So .3 feet is about 4 inches, close to the 5" Jeff needed...

SF Charlie
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Quote (Sym P. le (Mechanical)20 May 22 02:54)

The drawing is from Morabito's package for remediation.

Do you happen to have a pointer to this file? Thanks

SF Charlie
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See attachments split into three parts

The elevations are on page 71 in part 3

Or use Town of Surfside Public Records Search

• https://files.engineering.com/getfile.aspx?folder=5a6f7464-4413-4fbc-9e44-1

Part 2

• https://files.engineering.com/getfile.aspx?folder=a0f7073e-bebe-4d19-a74f-2

Part 3

• https://files.engineering.com/getfile.aspx?folder=f806cc6b-bc69-418f-9153-7

I'm sure you can georegister it in QGIS type in the values manually and get a contour plot if you have the time.
https://www.geodose.com/2018/05/how-to-create-cont...

Probably already been discussed, but looking thru SymPle's repost the South Wall Detail caught my eye. The only Section View I see where Morabito was planning to do repairs at South Wall, was the privacy part of wall on top of deck slab.

He just shows Patio Deck Slab, Edge Beam and garage wall as existing, with no indication of repairs to South Wall, other than Block Privacy Wall on top of deck slab.

This indicates no visible signs of problems when Morabito did his original field data collection to base repairs design on?

8.7.20 Survey also shows elevations good at South Wall.

Last page in SymPle's first attachment above.

Quote (Sym P. le (Mechanical)20 May 22 04:49)

Thank you very much!

SF Charlie
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Quote (thermobaric (Military)20 May 22 15:03)

This indicates no visible signs of problems when Morabito did his original field data collection to base repairs design on?
8.7.20 Survey also shows elevations good at South Wall.

1. Maybe he did not dig out the gravel outside the wall?
2. The issue at the south wall is not that it dropped, it is that it release tension on the pool deck, allowing it to droop ("bend or hang downward limply.").

SF Charlie
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With the amount of corrosion shown in pictures after collapse, at South Wall, it seems there would have been more spalling of concrete in that area?

Quote (SFCharlie (Computer) 20 May 22 15:30)

2. The issue at the south wall is not that it dropped, it is that it release tension on the pool deck, allowing it to droop

The issue of the slab dropping at the south perimeter is a product of the MH exposé.

The idea that it released tension is a misnomer as it never was tied in to the perimeter wall as though anchoring a tightrope.

Quote (thermobaric (Military) 20 May 22 15:03)

Morabito's idea of an edge beam would seem to be wishful thinking.

Quote (Sym P. le)

The issue of the slab dropping at the south perimeter is a product of the MH exposé.

It appears to be in this photo.

If I did the math correct the deck around the pool at the south privacy wall, at block column, on the West side of hot tub is 10.22 feet elevation, and like 3 feet away the elevation of finished top pavers is 9.94', or a slope of 3.36" over say a 3 foot distance, assuming 12" pavers.

I know they raised the finished paver floor height around the pool when they raised and rebuilt the pool edge gutter system.

Quote (Sym P. le (Mechanical)20 May 22 16:05)

that it released tension is a misnomer as it never was tied in to the perimeter wall

His video clearly shows rebar broken at the slab wall interface, and in a few cases short rebars "zippered" from the slab? Farther back, we see full length rebar zippers.

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Can the deck droop at south wall and the release of tension be separated. Let's say it drooped. Does it necessarily follow that it altered the diaphragm action in significant any way that led to an inevitable collapse. This might seem heretical. But there it is.

Quote (SFCharlie (Computer) 20 May 22 20:36)

you missed the last part of the sentence. The tie-in is not intended to anchor a tightrope.

Quote (zebraso (Mechanical) 20 May 22 20:54)

no

Quote (Sym P. le (Mechanical)20 May 22 20:56)

The tie-in is not intended to anchor a tightrope.

So, where does the tension of the deck catenary supposedly go?

SF Charlie
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This is not a tightrope, at least if its functioning as intended. A stiff slab will sit on its support and sag slightly, imparting a slight bending moment to the support if tied in, or toeing up slightly and pushing out on the support if not tied in. It's only when interior column supports fail that the functional aspect changes to the extent that it acts like a tightrope requiring tensile forces to be resolved with further design implications.

As far as my no answer, there is no such thing as drooping at the south support so it's a nonstarter.

Well then my question is overly convoluted to begin with. I thought it might be. There is such a thing as a bad question.

Add: incorrect premise. The assumption has to be the tie-ins broke after the collapse initiated. I am struggling to see a way around that.

Add more: It might help me in my mind to say there is not tightrope the spans the length of multiple columns. I mean I think at this point that is as ridiculous as can be. And then to say the deck between two columns is like a tightrope in two way flat slab? Seriously. What planet are we on?

By my account anyway but I've been wrong before.

It seems to me that if you throw out the principle of how two way flat slab works to explain how it failed then the explanation has already failed before it begins. And I imagine how that goes is: well it's in such a state that it no longer resembles flat slab and let's start from there. Well then the part about what caused it has been skipped over in order to explain it. I don't know though. It's just what it seems like to me. Somehow the long standing state of gradual decay supposedly changes the rules and it has morphed into a 7 headed beast? I feel like maybe Occum is knocking.

I'm not trying to put a damper on anything. Carry on.

And area that appeared to drop into sink hole was a low spot, based upon drain locations and survey, and over loaded more.

The cropped image below, IMO shows movement towards the sink hole.

Edit: Actually rotation of planter wall may be more of the opposite effect, or indication of movement West at South wall end.

I'm thinking about attempts at remediation. Clearly it was established there were multiple problems with the pool deck for a long time prior to the collapse. There were stalactites from secondary efflorescence. There were catch pans under the deck. There was spalling and cracks. The basement flooded. They injected epoxy, and tried to water proof the deck with a membrane and slope it to manage water better. These things failed. I just think that focusing on why and how they failed might be instructive. Was there a problem with the conception or implementation of the remediation? Conceivably if these things had succeeded in addressing the problems they actually saw, they would not have still needed catch pans under the deck in july 2020 and had water streaming down 76 in Nov 2020. Finally did the remediation actually make things worse?

Designed and built to fail in 15 years, and bondo’d to hide the defects

Both aspects of that statements are worth evaluating. Maybe they were not outright intentions. Standards change, and things were done in error also. Bondo vs epoxy. Yeah you are probably right in some sense. If it was really 15 years in hindsight they did one hell of a job. I don't want to believe that though. IMHO if they would have fixed the deck it should have made it another 40+. Assuming no one set a sail boat on the roof . What is the most evident difference between the construction of the North Towers pool deck and the South?

Reminds me of lead acid batteries designed to fail sooner than warranty period, to hook you into taking your $3 credit towards a new battery from same mfg/retailer, rather than punting them and buying another brand.

Well that's a scheme on something that's more or less a consumable. I don't know if that is cheating per se. Designed obsolescence is a real thing. But I can't think that anything in the construction of a mid-rise applies quite that way. When you cheat there it is a major crime. Radio Shack batteries were crap too and they got you back with the battery of the month club. But you accepted they were crap.

Quote (thermobaric)

Perhaps there is way more than 5% BOTS in what is published?

On the subject of action figures, I do apologize to everyone who has contributed to this thread for my Feb 13 attempt at transformer humor and I very much appreciated the correct and humorous response from Nukeman948. I had searched for hours to find that product image (with the knockouts in the correct position) without success. I eventually became embarrassed about seeing the associated image I had posted so I flagged it myself and it was quickly removed.

Quote (Reverse_Bias)

It appears to be in this photo.

Absolutely. The elevation survey shows a change of 3.36 inches (10.22-9.94) between two adjacent points close to the jacuzzi and the wall.

Quote (Sym P. le)

Morabito's idea of an edge beam would seem to be wishful thinking.

Agreed, and it doesn't acknowledge the presence of the sheet pile, which introduces discontinuities. The concrete is not bonded to the sheet pile in any way. Is it?

Quote (Sym P. le)

Actually, it is better to throw out their model. MH can update their model to help folks understand how this building fell down and why theirs won't.

Quote (Sym P. le)

Structural Madness's model, though also imperfect, lends better insight to this collapse.

It appears to me that both models have significant deficiencies.

For me the most important criteria for both the Miami Herald and Structural Madness models are:
1) Are they based on reasonably accurate initial conditions?
2) Can they be developed in time, as the collapse of the deck progresses, to produce a similar arrangement of debris at the end?

The problems I see are:
a) Neither model appears to make provision for the construction joints that we know played a critical role in limiting the area of deck collapse and also played an important role in the geometry of the deck after the collapse. For example, the linear depression that runs East-West through the pool deck gate.
b) Neither model appears to include the 19"x19" penetration through the deck that was formed to allow exhaust from the pool equipment room to be vented at the corner of the pool deck.
c) The Structural madness model does not make any allowance for corrosion of the steel or degradation of the concrete and we know they are both critical factors in the collapse.
d) Neither model appears to include any provision for as-built, or as-repaired, conditions of the deck at the Southern edge, as shown below:


Credit to Construction Engineering and Failure Analysis for originally posting that clip.

e) Neither model explains why there would be a dramatic discontinuity in the deck between the pool equipment room exhaust vent and the gate. The area identified by thermobaric in the image above.

Quote (thermobaric)

area that appeared to drop into sink hole

@IanCA, I recently re-watched Jinal’s video of early August, 2021, and IIRC he verbally albeit briefly touches most of the contributing factors on your list, including some construction joints, corrosion, concrete, and maintenance failures…but not the deck penetration. It would be great to see a follow-up from Jinal to look in greater depth at contributing factors.

The MH model is, in my view, more take-it-or-leave-it. Having a background in theatre (rigging) and outside-plant telephone engineering (pole setting and guying,) I am skeptical of the tightrope and compression theories for the south wall and don’t put Jinal’s failure model in the same class as the Miami Herald’s. Plus Occam’s Razor.

IanCA, In no way was my >5% BOT analogy in published information related to your transformer post. Since you took it that way, I deleted that post.

When I duck 🦆 go’d - ‘BOTS’, the Green BOT was 2nd imagine displayed, so I used it.

Edit: Rather my post was referring to disinformation, destruction of evidence and cover up of evidence.

Since IanCA, posted the image of the exposed top of sheet piles in area of interest, I have gone and watched some of Construction Engineering & Failure Analysis’s latest videos.

First a warning ⚠️, prepare a stiff drink 🍹 to assist in the painful experience of listening to this guy think out loud in real time, and ramble and ramble to drag things out.

The reward is, you will see images I have not seen before, and receive data you have not seen or heard before.

Filtering thru the noise, is a lot of information not being released by ‘The Ministry of Truth’.

Like evidence of control joint E-W along I14, and crack pictures, and discussion of problem with columns being offset from straight line and the possible effects of that.

We are missing so much information that is being shared to this guy, that leads you down a better understanding of what may have happened.

Edit: No Pain - No Gain

Edit: Have run into some of his videos that say they are private, so I login to youtube and then it tells me they are unavailable. So information is being concealed, by youtube, for some reason, as author claims it is not him doing it.

Quote (MaudSTL)

It would be great to see a follow-up from Jinal to look in greater depth at contributing factors.

I completely agree.

What I would also like to see is his analysis developed past the point where the column which he identifies as the weakest, punches through the deck. In which sequence do the remaining deck support columns punch through? Does the collapse progress to the Southern wall? Does it result in the dramatically different final conditions we see at the wall East and West of column line K? If not, modify the initial conditions and repeat the analysis from the beginning.

@thermobaric Understood. Thank you anyway.

Quote (thermobaric)

The reward is, you will see images I have not seen before, and receive data you have not seen or heard before.

Agreed.

Quote (thermobaric)

the image of the exposed top of sheet piles in area of interest,

I'm interested to hear what others think but I think the feature highlighted in the image in my 21 May 22 05:30 post is closely spaced rebar rather than the top of the sheet pile.

Cheers.

Quote (MaudSTL)

I am skeptical of the tightrope and compression theories for the south wall

Agreed. Especially considering the condition of the deck-to-wall connection at the Southern wall between column lines G.1 and K.

Quote (SFCharlie)

Here is my first attempt to visualize the elevations.

Thank you very much for taking the time to do that work SFCharlie, it is helpful.

Quote (IanCA (Mechanical)21 May 22 05:30)

Photo
Quote (thermobaric)
area that appeared to drop into sink hole

Since the responders are looking over the wall at the debris, I assume they are standing on the gravel that the construction to the south replaced the street (and walk?) with.
The exposed rebar seems to me to imply that the construction changed the structure of the wall.
I bet they didn't analyze this.

SF Charlie
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Some more work in the South Wall Area:

SF Charlie
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We don't have any information to conclude that the dip is anything other than a surface feature. A 4" step stemming from slab deformation would be immediately apparent in the garage and alarmingly so.






Note the significant amount of sand (or additional topping) under the tile in the area between the hot tub and the pool. In the first image, it appears that the sand layer tails off to nothing.

Quote (Sym P. le (Mechanical)20 May 22 22:35)

This is not a tightrope, at least if its functioning as intended.

Yes! That is not the intent!

Quote:

A stiff slab will sit on its support and sag slightly, imparting a slight bending moment to the support if tied in, or toeing up slightly and pushing out on the support if not tied in.

Yes! A properly designed slab and column design will function like this!

Quote:

It's only when interior column supports fail that the functional aspect changes to the extent that it acts like a tightrope requiring tensile forces to be resolved with further design implications.

I would have preferred to say "column connections to the slab fail", but yes!

Quote:

there is no such thing as drooping at the south support

Yes! The "drooping" in the slab, seems to have occurred between the wall and the first column, been worst over the 30 foot span, and between columns.

I apologize for not making myself clear!

SF Charlie
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I think I understood you, but it seems people don't connect with the vast difference in support that a continuous wall offers over a slim column.

Quote (Sym P. le)

it appears that the sand layer tails off to nothing

Thanks for the photos. Do you think that was done intentionally to prevent rainwater from draining into the pool and hot tub, perhaps?

Quote (Sym P. le)

the vast difference in support that a continuous wall offers over a slim column

I agree with this in theory, but in practice, if design was weak (a single row of rebar at 12" centers, with minimal engagement), the construction was not well monitored (not considered a critical part of the structure), after years of corrosion, with regions bounded by construction joints, and the deck cracks as shown below (from thread 15), then the deck will be pulled from the wall.

Weak wall-deck connection:



Location of cracks and movement of deck matching photographic evidence (I hope you don't mind me using the version with your markup MaudSTL):


Edit: If the wall-deck connection was as strong as it should be in theory, why did it fail at all? I don't believe there is a mechanism that can achieve the tension cracks seen in the top of the stampcrete in the parking deck if the collapse begins North of column line 15. Can anyone sketch a sectional elevation showing the intermediate positions of the deck components that achieves those tension cracks in the top surface?

Unfortunately, from a physical standpoint, that sketch is not realistic.

Quote (Sym P. le)

Unfortunately, from a physical standpoint, that sketch is not realistic.

Please can you be specific? I would like to understand more about your perspective and see if it can be improved at all.

It needs a support under the proposed break on the right side of the image.

IanCA, I am not sure exactly where in your section view the cracks area located. Perhaps you could add them to the image below, where I show clearly the initial dropped area in MH released phone aligns with 19"x19" slab cut out for pool exhaust fan, thus no continuous rebar attachment to South Wall in North-South Plane which is the 'heavy hitter' of the two way slab... Thus could explain a more localized failure at first, and be source of your crack propagation?

Quote (Sym P. le)

It needs a support under the proposed break on the right side of the image.

That section of the deck is supported in cantilever by the columns to the north:



Remember the crack in the top surface in tension runs from the South-West at planter at column line G.1 to the North-East column at Column line K as shown in the diagram in my post on 27 Feb 22 18:29. Included again here for convenience.

Quote (thermobaric)

Perhaps you could add them to the image below,

Approximately like this. With the section on column line I.

And of course, there is a discontinuity E-W too, at 19"x19" Hole in slab.

A lot of Construction Engineering and Failure Analysis Videos are no longer available on YouTube, indicating the 'Ministry of Truth' had them pulled?

However, the recent ones I watched, suffering thru the noise, I did find nuggets buried in each once, which indicate that I14 and I 14.1 could be the center of initial failure area. He even showed Leman's Assumptions for her model that were way off, and drove the answer the model spit out. I see why you have to throw out the MH model now, based upon invalid constraints input into the model.

He also supports parking deck failing first, then patio deck, then building. He also makes an argument the insurance companies don't just settle out of court for a Billion Dollars without getting some benefit out of doing this. That being they would be able to raise insurance premiums drastically to recoup their payout.

He also shows NIST destroying evidence in a video, and dragging a rebar out of a sample they cut with jack hammers and sledge hammers. Also the fact they pulling samples in the wrong area, and had already destroyed the evidence in the potential root cause area, as if they had already decided what the cause would be.

Tough to listen to his videos, and you will need to keep your fast forward key warm. However, he is receiving information the general public does not have access to.

Quote (thermobaric (Military)21 May 22 22:42)

A lot of Construction Engineering and Failure Analysis Videos are no longer available on YouTube, indicating the 'Ministry of Truth' had them pulled?
...
Tough to listen to his videos, and you will keep your fast forward key warm, but he is receiving information the general public are not being allowed to see.

He is excellent at seeking out info for his profession as a youTuber, but he hordes sources very close to his chest. I found this blog by searching with Google for his sources. His 'Ministry of Truth' is probably a copyright complain by the originator of his content.

SF Charlie
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Quote (thermobaric)

He even showed Leman's Assumptions for her model that were way off, and drove the answer the model spit out.

Would you please link to that particular video? I’d like to try to listen to it.

FWIW, I listened to Kai’s early videos, quitting when he started focusing on insults received and starting fights with other YouTubers. But as I recall, he almost immediately after the collapse theorized that the locus of failure was the very area we are currently discussing, based on his construction expertise and analysis of how the punching shear scraped specific sides of the columns and how the slabs “butterflied.” I think Kai intuitively understands materials.

Quote (MaudSTL (Computer)22 May 22 02:42)

I listened to Kai’s early videos

Are you speaking of Kai Kostack?

SF Charlie
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Or this Kai

Quote (Construction Engineering & Failure Analysis)

4 months ago
I am working on a video series that will prove magnetic frequency and NOT gravity is what ''holds'' our planets together...

SF Charlie
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Quote (MaudSTL)

Would you please link to that particular video? I’d like to try to listen to it.

I remembered watching that video. Here is the link:

Champlain Towers Collapse Dawn Lehman WRONG GYM Disregarding VIDEO evidence

Don't know why you bothered to link to him he's an unhinged narcissist. He bashes everyone. He thinks he's the only person with any knowledge on the subject, and he bashed Allyn Killscheimer, he bashed NIST, bashed Dawn Lehman, He bashed Josh, he bashed me, and he lied and told people on several videos I'm a tool salesman. He falsely accuses everyone of stealing his ideas, yet all he does is comment on my videos and Josh's videos and bashes everyone. He knows more than the top ex[erts in the field.

Quote (Jeff Ostroff)

Don't know why you bothered to link to him

I completely understand that a lot of his comments are offensive and that is regrettable. But he does make some valid and important observations that should not be dismissed.

Quote (MaudSTL)

Would you please link to that particular video? I’d like to try to listen to it.

@MaudSTL Please let me know when you have the link.

Are the images below a possible explanation for the apparent vertical offset at the planter?

Far view of planter:


Near view of planter:


Inside view of planter:


If you look closely at the gap you can see two branches emerging. Both have been torn off, the top one appears to have scrunched the paint up as it was broken off.

@IanCA, thanks, I got it.

Quote (MaudSTL and IanCA)

IanCA I appreciate you providing the link to Kai's video. I must say it is one of the easier ones to watch, and does contain logical conclusions from the evidence pictured.

I also stumbled upon the one where he gives you some perspective on how connected Michael and Cassie Stratton are to the White House, and casued me to duck duck go Michael Stratton. I will provide a quote from Michael Stratton's web site, and a link to it.

I leave it to the reader to come to their own conclusions as to whether this person's connections had anything to do with the large settlement for the individuals that lost their lives in the collapse. 'Quit quo pro' as they say.

Kai's message also could explain why NIST jumped in and took over the investigation, and that a Billion Dollar Settlement is reached on an unproved theory. I will also include an article from ENRsoutheast.

First a quote form Michael Statton's Web Site, and link:

"Distinguished Democratic strategist. Decades of on-the-ground campaign experience across the United States. Trusted confidant of business leaders and policymakers."

"Mike Stratton draws on his 50 years of frontline experience in Democratic politics managing campaigns and serving in senior government positions to shepherd clients through multijurisdictional policy issues. He served in top positions for 10 presidential campaigns, worked in the U.S. Senate, and served as an appointee in the Carter and Clinton administrations. Now, he offers clients keen insight into the interplay between federal, state and local policy arenas and advocates before all levels of government to advance industry objectives.

Trusted by mayors, attorneys general, governors and federal policymakers, Mike understands how to activate grassroots and grasstops organizations to achieve his clients’ business goals. He provides critical deal-specific consultations for domestic and international clients, negotiating sophisticated business deals, peace initiatives and foreign policy issues.

A leading voice in the hierarchy of the Democratic Party, Mike develops and executes strategies to achieve electoral victories for Democrats across the country. He has served as a member of the Democratic National Committee, and most recently, was reappointed by the Biden campaign.

A native of Durango, Colorado, Mike played an integral role in the successful campaigns of Sen. Michael Bennet (D-CO) and former Gov. John Hickenlooper (D-CO). He is active in state politics across the country and is considered the dean of advisors to the Democratic Governors Association and the Democratic Attorneys General Association."

https://www.bhfs.com/people/policy/michael-stratto...

Next the ENRsoutheast article:

https://www.enr.com/articles/54126-unproven-theory...

Edit: I think IanCA has identified that roots may have played a role in the separated planter corner, and perhaps that area had been trouble before and roots were cut back and it skimmed over and finally let go. I did see in some of Kai's video's where it clearly looks like the planters on both sides of the parking deck/patio gate were already sagging.

I would also like to note Kai talks about torque on two way slab created by columns that are offset and NOT aligned, and point out that the worst area in between K13.1(under East Planter wall) and K15 (parking deck west side of planters).

He cites ACI recommendations on column offsets and says design is not complaint even in 1979. I think SFC has a copy of those docuuments and could possible comment on that or provide confirmation of Kai's statements about allowable offset angles between columns on 2 way slab.

Edit: Link to some available Kai video's

https://www.youtube.com/watch?v=babReMh9Exs

https://www.youtube.com/channel/UC-_5I5xDiFVcxlnG7...

https://www.youtube.com/watch?v=jXdULPG7rQE

Quote (IanCA)

Are the images below a possible explanation for the apparent vertical offset at the planter?[quote ]2IanCA (Mechanical)22 May 22 05:08


Yes, and an example of how only certain information leaks to control the narrative. So is this another Red Herrin Leak?
So per IanCA's graphic, the roots are raising one side of planter wall, while displacing East the other side.

Quote (thermobaric (Military)22 May 22 14:11)

https://duckduckgo.com/? hiy q=construction+engineering+and+failure+analysis&t=iphone&iax=videos&ia=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DbabReMh9Exs

Is this video behind Kai's paywall? I can't make it work. Thanks.

SF Charlie
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Sorry SFC, that link was done on my phone and trash. Try this one:

https://www.youtube.com/watch?v=babReMh9Exs

Quote (thermobaric (Military)22 May 22 15:10)

Quote:
2IanCA (Mechanical)22 May 22 05:08
Are the images below a possible explanation for the apparent vertical offset at the planter?

So per IanCA's graphic, the roots are raising one side of planter wall, while displacing East the other side.

I don't see anything about roots in IanCA's graphic?
The red ovals have been IDed as elastomer, possibly from a previous repair.

Thanks the link worked

The third long video, shows the crack on the East side of Column K13.1, which would appear to say not root or not just root damage.

Quote (Jeff Ostroff)

Don't know why you bothered to link

@Jeff Ostroff Let me know if you want me to delete my post with the link, please.

Quote (SFCharlie)

I don't see anything about roots in IanCA's graphic?
The red ovals have been IDed as elastomer, possibly from a previous repair.

Thanks for your feedback SFCharlie. I will add further notes to the graphic.

I feel confident that the longer red oval contains a root or branch. It doesn't connect to other areas of elastomer, it has a different color, it has an outline suggesting fibers and less flexibility, and it extends from the crack, not the surface.

I did speculate about the contents of the upper red circle I cannot really see that clearly but I see the paint was scrunched up. That was possibly done by the object in the lower circle which sprang back down after being pulled up and broken off?

On column 76, note that the column/slab connecting rebar is oriented in a north/south direction as opposed to coming off the corners at a 45° angle. It seems to be unique to column 76 although I haven't looked closely at all of the other columns yet. I'm not sure what, if any, weakness this may have introduced to the structure locally or on a broader scale but it's hard to ignore that things were going wrong at this connection prior to collapse.

Quote (Sym P le)

On column 76, note that the column/slab connecting rebar is oriented in a north/south direction as opposed to coming off the corners at a 45° angle. It seems to be unique to column 76 although I haven't looked closely at all of the other columns yet. I'm not sure what, if any, weakness this may have introduced to the structure locally or on a broader scale but it's hard to ignore that things were going wrong at this connection prior to collapse.

To me in the photo, I see a bias in the South Side rebar to the West (towards parking deck), but mostly a straight down drop it appears

It's not about the rebar pointing down, it's about the compass direction, which should be off the corners at 45°. The falling slab would not (and didn't at any other column) reorient the direction of the installation. It would be a stretch to suggest that the rebar became twisted during the collapse. Nonetheless, it's a question of what if any weakness this introduced to the structure.

The problem with rebar installation is that no one cares how good a job you did until the structure falls down and all of your crappy work is exposed for the world to see.

In the photo posted by Sym P. le (Mechanical) 17 May 22 01:30, we can see the joint after it was picked apart, and behind that, what it was like before it was picked apart. there may be small roots in the joint, but roots can't explain the large displacement including in the deck.
Please review my diagram at SFCharlie (Computer) 19 May 22 14:33. Thanks

SF Charlie
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Quote (IanCA (Mechanical))

Are the images below a possible explanation for the apparent vertical offset at the planter?

You make a good case. This might be an example of people seeing what they are most predisposed to see. Confirmation bias. Those darn photos. An engineer looked at the actual site and said it was roots. Why is it so easy just to dismiss that?

Am I missing something here?




From the picture previously posted below, we know water was pouring down the South side of the column, so apparently already a crack on that side.

The compass heading to SW of that one rebar could be the tug from the parking deck area collapse?

Typical punching shear failures leave a piece of the slab hanging on the column head and more importantly do not cause damage to the column head itself. In this case all of the column heads suffered moderate to severe damage, even the one next to Jacuzzi that still had the back half of the slab attached to it.

I could picture 1 or 2 columns doing this but since it was every deck column, it points to a design or material defect in the columns as well as the slab.