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# Miami Beach, Champlain Towers South apartment building collapse, Part 1154

## Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

One thing that’s been a subject of speculation is the UPH Addition and what impact it may have had. I think it’s important to note that there is every indication it was intended to be constructed from the very beginning.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Santos81)

Not arguing, but what leads you to that conclusion?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (AusG)

Not arguing, but what leads you to that conclusion?

This specific page:

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Santos81 (Specifier/Regulator)9 Aug 21 02:57 Quote (AusG) Not arguing, but what leads you to that conclusion? This specific page:)

Could you please elaborate a bit?
Thank you,

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley)

Could you please elaborate a bit?

It’s one of the few from the original permit set (identifiable by the ring punches and signatures) but shows only reinforcement detail and minor changes required at that level for the UPH.

Compare to the same page from the “New Penthouse Addition - South” application set that came later (but has the incorrect vertical openings):

FWIW, the north tower has one of these oddball pages as well.

If someone else has a better explanation, all eyes are upon ya.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Today's Miami Herald article is summarized in a large twitter thread with lots of graphics. It's mostly about the plans in the design not meeting code. All the columns in the portion that collapse had "overcrowding" issues.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Santos81 (Specifier/Regulator)9 Aug 21 02:27)

One thing that’s been a subject of speculation is the UPH Addition and what impact it may have had. I think it’s important to note that there is every indication it was intended to be constructed from the very beginning.

Not that I think this was part of the cause, but it's been reported that the Town stopped the construction at one point because the developer didn't have permission to build the penthouse, and it violated local ordinances (which were later changed to appease the developer). From Wall Street Journal:

"The developers of the collapsed Surfside condominium tower worked around local building codes by adding a penthouse that wasn’t part of the original plan, a review of town building records shows.

Plans submitted by the developer of the Champlain Towers South initially called for 12 floors of residential units. The developer decided to add a penthouse, which increased the building’s height by about 9 feet with an additional floor. That put the tower slightly above the town’s legal height ordinance at the time."

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (CE3527)

but it's been reported that the Town stopped the construction at one point because the developer didn't have permission to build the penthouse, and it violated local ordinances (which were later changed to appease the developer)

Revoked the permit briefly so that could be “fixed”

Grease
Scandal
Election

Resume

I put it up there with the “3.9 earthquake/aftershock” that:

Wasn’t an actual earthquake

Occurred more than 300mi NNE of Miami; further away than the actual very active seismic area to the south (yes we felt that 7.7 and the 6.8, 6.5, and 6.1 aftershocks)

Didn’t even register on the seismometers in Doral that are used to monitor the quarry blasting, such as on the evening of June 23. This has already been ruled out as a contributing factor after monitoring the site during last months blasting.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Thanks @Optical98 for posting the link to the article from the Israeli team, very interesting and respectful read.

This part is sticking with me: "We locate Ilan and Deborah in Apartment 811, as we expected. They lie side by side, embraced, holding their ID cards. Perhaps they felt the tremor." It's a fascinating and heartbreaking detail, obviously they knew that building was coming down and they weren't making it out. I thought maybe they were older so they didn't have the physical capability to try to escape, but they were only 21...they had enough awareness of the situation to understand what was happening, enough time to gather their identification and go to a specific spot to fall together. I have to think that something prevented them from trying to escape.

Being in the x11 stack, we know those units sustained damage prior to the collapse...after watching the video from 711, I wonder if the front door to 811 was compressed by the failure that woke up the camera one story below them? Ms. Monteagudo in 611 described the crack she saw forming as coming from above, perhaps every unit in the stack above her was unable to open their doors, as there's never been mention of anyone being found in a hallway attempting to escape.

As though the imagery of those final moments wasn't horrific enough already...

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

arbitraria,

Yes, I noted that as well.. the only thing I could think of is if we consider the 904 survivor details that seem to indicate that some of the top floors dropped 1st, to the 8th and maybe just to the west end ( x4 and x10), that could have blocked 811's exit.

"Sara Nir was up late, checking her email when she heard knocking sounds that went from a soft tapping to hard pounding to a frightful crash overhead -- as if a wall had collapsed in the unit above her ground-floor condo.

Raysa Rodriguez was sleeping in her room on the ninth floor when she awoke disoriented. The building was swaying "like a sheet of paper." She ran into the hallway to find that it had been impaled from floor to ceiling by a concrete pillar; the doors of the elevators were shorn off, exposing the shafts."

Nir is describing something tipping (knock knock knock) and falling over.
And how did a column "impale" the hallway on west side of the shear wall?

"Metallic boom" was heard and Furman thought something hit the elevators as well.

It's amazing Monteagudo (611) escaped. You'd have to think she must have already gotten to the stairwell while Nir was in the Lobby.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Jedidad (Computer) 9 Aug 21 12:56 Here's a PDF that goes into a little more detail than the Miami Herald tweets: Link Also uploading it. )

Its also interesting that they made a statement about the bottom cover on the plaza slab being too small. The conventional wisdom is that this is, strictly speaking, a durability and not a structural capacity problem. Videos of the underside of the parking garage by the prospective buyer certainly showed some water issues but didn't seem to show any serious concrete spalling that would be indicative of inadequate cover and subsequent rebar corrosion that would have reduced the load carrying capacity. If the investigation concludes that the plaza deck concrete and rebar weren't significantly deteriorated to the point where collapse was imminent, then the design methodology for these column supported slabs will need to be revisited.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Question for the SEs, just looking at the facts at hand. Knowing there are many condo buildings along that shore in similar build and age.

What issue would you want to correct first?
I mean in hindsight, it certainly looks like the garage should have been shored up immediately, even if it wasn't the 1st project. It was part of the recert plan, but evidently not prioritized.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

@Optical98
It actually was a priority. A delay in alternate parking just put it on pause.

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

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Some interesting snippets in those articles, thanks for posting.

@tmwaits1 Yes, absolutely a structure doesn't need to collapse immediately to have a design or build time flaw, the original design is supposed to have a large safety margin to deal with deterioration over the design lifetime and variations of use, you can screw that up pretty badly and it will still hold up on day 1 with favourable conditions.

Those columns, just from looking at them as a layman, always looked unreasonably thin. (There's a 4 storey building in my town and it has bigger columns than that.) We'd all seen the photos showing not enough rebar, but the points in there about being too small to hold all the rebar at a safe interval sort of explains how that decision might have got made. I don't know how we can think that CT North is safe though in that case - I know there are differences in the slab design around the maybe crucial 9.1 line slab step, but CTN has thin columns and quite likely missing rebar too.

Re @Markbob2 - I'm still not convinced by his interpretations of those images*, but trying to look into the area of the first known collapse in the morning after pictures and see what's down there seems quite a legitimate line of enquiry that doesn't deserve the ridicule he was getting at the bottom of thread 10. There's still no good mechanism proposed afaik for why the pool deck failed, or for the noises in higher parts of the building before that.

* in particular I don't see how that green bag of tar paper could have fallen some 10m beyond the perimeter of the building, nor do I see how a heavy AC or crane+davits on the 1210 roof could have fallen down in front of 111 and the Nirs not reported that

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Question for the SEs, just looking at the facts at hand. Knowing there are many condo buildings along that shore in similar build and age. What issue would you want to correct first? )

In my experience this problem starts with the original plans, which were sloppy and never should have been approved for construction. This tells me there was insufficient oversight from the local building department. This is a major problem in Florida at both state and local levels and is a consequence of the average citizen's ignorance of the effective role of government in this process and the value of well paid qualified government staff. Low taxes = low salaries which means you will not have qualified people reviewing building plans. If you want to connect the FIU Pedestrian bridge collapse and Surfside this is your common factor. The FIU bridge collapse happened in part because FDOT has been scaling back real engineering oversight for many years (to reduce costs to the taxpayers) so there was nobody to stop the project even when the signs of imminent failure were obvious.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

You're forgetting about permit fees, which should be paying for the "oversight". Isn't that the reason there ARE permit fees?

Possibly "they" gave the developer a big break on those fees, and thus didn't have enough money to cover the costs for doing their job right. One could ask why "they" would do such a thing.

spsalso

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (If someone else has a better explanation, all eyes are upon ya.)

Both drawings are titled SECOND FLOOR FRRAMING PLAN.
So they changed the Second Floor in order to add a penthouse? Probably due to added wind exposure so more drift moments in the slab and columns at the second floor level. The shears and moments for the slabs and columns are increased by one floor due to the addition at the top. Originally the First Floor slab and columns had similar moments because they were an equal distance ( same number of floors) from the top. And the First Floor slab was thicker, as I recall.
The columns have more vertical load and more bending if the penthouse is added. Were they increased in capacity as a result of the PH add?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley (Structural))

SECOND FLOOR FRRAMING PLAN

Is this covered by the 2nd through 9th being the same layout? I actually don't know. Just asking.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (zebraso (Mechanical)9 Aug 21 20:23 Quote (Vance Wiley (Structural)) SECOND FLOOR FRRAMING PLAN Is this covered by the 2nd through 9th being the same layout? I actually don't know. Just asking.)

I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor?
The vertical load design would be the same for floors 2 and above, with the roof slab likely different (less load?).
The lateral design would increase the moments in the slabs and columns as the distance from the top increases.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Optical98)

how did a column "impale" the hallway on west side of the shear wall?

Maybe they just saw a column that had been exposed by falling drywall/framing during all the swaying.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Was it a column or concrete roof beam supporting the large common areas AC unit? I have no idea, but the RC roof beam was large that was supporting the large AC unit and it was almost due North of Elevator shaft.

A lot of posters had said the columns were fine in axial loading, but I do not remember seeing any analysis of the lateral stability of the slender columns in the collapsed section, and the effects of drift on the flat slab to column joints. Especially the effect over time if those joints are being stressed due to say uneven loading of 2-ways slabs, wind loading, construction vibration next door, etc. Seems to me those under nourished flat slab and slender columns were being over stressed in at least E-W direction, and time would be the enemy if drift is excessive.

Also no one has discussed the effect of the too much rebar in the slender columns of the collapsed portion, as mentioned in Miami Herald Investigation.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Optical98)

Thanks! I had no idea! This will take several seconds of my Fifteen Minutes of Fame.

On another topic, I have the impression that there may be some confusion around the timeline. In case I am right, following is some clarification.

#### Quote (Optical98)

"Sara Nir was up late, checking her email when she heard knocking sounds that went from a soft tapping to hard pounding to a frightful crash overhead -- as if a wall had collapsed in the unit above her ground-floor condo.”

Nir is describing something tipping (knock knock knock) and falling over.

Furman thought something hit the elevators as well.

This is the same knocking that Chani Nir heard when she got home at 11 PM. We still do not know if the security guard also heard it, or if anyone heard it prior to 11 PM.

The knocking is followed by the the first collapse at 1:10. This is what made Sarah Nir go to the lobby to complain.

#### Quote (Optical98)

It's amazing Monteagudo (611) escaped. You'd have to think she must have already gotten to the stairwell while Nir was in the Lobby.

Ileana Monteagudo was awakened by the second collapse: the deck collapse. While she was waking up and going to check her sliding door, Sarah Nir and Shamoka Furman, who were in the lobby discussing the first collapse, heard the second collapse. Sarah ran over to the window and saw the surface parking part of the collapse, and then ran to roust her kids. At that point, Ms. Monteagudo was seeing the crack run down the wall of her living room…we still don’t know which exact wall was the one where the crack was opening.

#### Quote (Optical98)

…the only thing I could think of is if we consider the 904 survivor details that seem to indicate that some of the top floors dropped 1st, to the 8th and maybe just to the west end ( x4 and x10), that could have blocked 811's exit.

Raysa Rodriguez was sleeping in her room on the ninth floor when she awoke disoriented. The building was swaying "like a sheet of paper." She ran into the hallway to find that it had been impaled from floor to ceiling by a concrete pillar; the doors of the elevators were shorn off, exposing the shafts."

And how did a column "impale" the hallway on west side of the shear wall?

Raysa Rodriguez woke up as a result of the third collapse: the collapse of the building. How does her statement describe a pause in the early part of the collapse that occurred while she was still asleep?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley)

I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor?
-1kPSI concrete for 9, 10, 11, 12, 13 from lower levels.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

"Was it a column or concrete roof beam supporting the large common areas AC unit?"
"Maybe they just saw a column that had been exposed"

Listening to Furman on these videos, she heard something hit the elevators/shaft, she points up.... Raysa is pretty descriptive and she is on the 9th floor.

And I can't find the source right now, but I remember reading someone saying that the elevator shaft was lurching into the hallway, I was thinking this is odd because we can't see anything outside the shear wall.

So I think something fell and hit the shaft.

Below again is the exact quotes from the article, in case AAM didn't see my post.

"Sara Nir was up late, checking her email when she heard knocking sounds that went from a soft tapping to hard pounding to a frightful crash overhead -- as if a wall had collapsed in the unit above her ground-floor condo.

Raysa Rodriguez was sleeping in her room on the ninth floor when she awoke disoriented. The building was swaying "like a sheet of paper." She ran into the hallway to find that it had been impaled from floor to ceiling by a concrete pillar; the doors of the elevators were shorn off, exposing the shafts."

Nir is describing something tipping (knock knock knock) and falling over.
And how did a column "impale" the hallway on west side of the shear wall?

"Metallic boom" was heard and Furman thought something hit the elevators as well.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Maud,

My post is more about what was happening on the 8th and 9th floors... why the couple in 811 had the time to gather their IDs and then embraced each other, they were found this way, as if they couldn't get out. 904 mother and daughter end up on 8th flr long enough for the mom to crawl over and cover her daughter...before they descend further.

I'm not proclaiming time-stamps, though Furman makes it pretty clear she first heard booms from above thinks it's the elevators, then the 2nd boom was the pool deck.

None of this has anything to do with "Chandi in the shower at 11pm"

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Optical98,

If I am not mistaken, the elevator doors would be set in CMU infill walls. If the doors are gone, odds are the CMU walls around doors are gone too. All of that metal and CMU are going to fall down the elevator shaft probably, and make a hell of racket on the way down and when it lands on elevator car at bottom.... Building swaying would be worse the higher the floor, I would imagine.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

That makes sense, could be what Furman heard first. Regarding Rayza seeing a column impaling the 9th flr hallway... I guess I'm gonna have to look at the plans again...

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

If I am not mistaken, the elevator doors would be set in CMU infill walls. If the doors are gone, odds are the CMU walls around doors are gone too. All of that metal and CMU are going to fall down the elevator shaft probably, and make a hell of racket on the way down and when it lands on elevator car at bottom.... Building swaying would be worse the higher the floor, I would imagine.

The UPH corridor was part of a substantial beam group that was integral with both the Common Interior Condenser Support structure and the elevator shaft above the top of the shear wall. When this was ripped away just below the machine room, it caused the elevator assemblies to move. I’ve heard that the deformation was enough to allow the counterweights for elevator 1 (northern of the two) to come off the guiderails.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Optical98)

…Furman makes it pretty clear she first heard booms from above thinks it's the elevators, then the 2nd boom was the pool deck.

I know that Sarah Nir stated that she perceived the first collapse as a wall collapsing in the apartment above.

And I also know that Shamoka Furman thought the first collapse had to do with the elevator, even though there were no alarms.

But what is new to me in what you are saying is Shamoka Furman perceiving the first collapse as coming from above. I hadn’t seen anything that indicated directionality. Would you please provide a link that I can add to the timeline?

P.S. Chani was in the shower at 1:10.

>>>Edit: Keep in mind that the elevator was still functioning as the deck collapsed. The Vazquezes experienced the deck collapse at 1:15 AM from inside the elevator, which brought them to the lobby “as usual.” So the elevator was working after the first collapse at 1:10 and through the second collapse at 1:15. Whatever happened to the elevator occurred after 1:15.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley)

Both drawings are titled SECOND FLOOR FRRAMING PLAN.
So they changed the Second Floor in order to add a penthouse? Probably due to added wind exposure so more drift moments in the slab and columns at the second floor level. The shears and moments for the slabs and columns are increased by one floor due to the addition at the top. Originally the First Floor slab and columns had similar moments because they were an equal distance ( same number of floors) from the top. And the First Floor slab was thicker, as I recall.
The columns have more vertical load and more bending if the penthouse is added. Were they increased in capacity as a result of the PH add?

You’re right on the money…no pun intended.

UPH required revisions to Foundation, Basement, Lobby, Second, and roof levels specifically for wind load resistance. The second floor framing plan with partial details and subtle but significant differences sticks out like a sore thumb. Legitimizes the rumors regarding a bought it yet to be obtained variance while simultaneously dismisses the suggestion the UPH was a later addition that wasn’t part of the original calculations.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Santos81)

The second floor framing plan with partial details and subtle but significant differences sticks out like a sore thumb.

Could any of those differences on Floor 2 or elsewhere have resulted in a failure that would account for Collapse 1 heard on the first floor at 1:10?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Maud,

"you are saying is Shamoka Furman perceiving the first collapse as coming from above."

I did not say she perceived the 1st booms as the 1st collapse.

Taking into account what All About Money says about CMU blocks possibly falling down onto the elevator cars...

And Santos

" it caused the elevator assemblies to move. I’ve heard that the deformation was enough to allow the counterweights for elevator 1 (northern of the two) to come off the guiderails."

I don't think it matters, people tend to point up when talking about elevators anyway.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I think Santos81 explains the big metallic noise in elevator shaft, plus perhaps doors and CMU's falling. The Corridor Beams Santos81 mentions would explain the West side hall ceiling puncture very well. The after collapse photos show the elevator shaft about the 12th floor roof line has shifted and broken one or more columns where it attached to 12 floor roof. So the corridor beams and columns with CMU in fill were moving and falling perhaps very early.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Santos,

Any idea why there seemed to be a brief pause of the upper floors collapsing to the 8th floor?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Optical98 (Computer))

Yes, I noted that as well.. the only thing I could think of is if we consider the 904 survivor details that seem to indicate that some of the top floors dropped 1st, to the 8th and maybe just to the west end ( x4 and x10),

When I read 904's account (which I don't have handy to reread), I didn't get the impression that there was a delay in the collapse. IIRC, they were almost to the front door... The way I visualize the situation is that since the x04 units are the units that were torn in half, they were originally in a portion of 904 that was collapsing... and either due to the way the floor fell or due to their momentum from running to the door, they fell one story into a portion of 804 that hadn't collapsed... yet. As the rest of building behind them continued to fall past them, mother covered daughter... then once most of the building had fallen below the 8th floor, the section of 804 they were on broke off and they fell five stories onto the top of the rubble.

I don't know if this is a viable scenario, but it was what I got from the account I read.

#### Quote (arbitraria (Civil/Environmental))

I wonder if the front door to 811 was compressed by the failure that woke up the camera one story below them?

After watching the 711 video, the idea that the front doors may have gotten wedged and prevented people from escaping is one of the two things about the collapse that keeps me up at night (the other being that the eastern stairs led nowhere safe). Just curious, does anyone know what kind of doors they were? I think steel doors are required in NYC, and my friend's door is robust. I can run through most non-steel doors... but to escape their unit, it would be easier to rip a hole through the drywall.

BKNJ

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Demented

Quote (Vance Wiley)
I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor?

"-1kPSI concrete for 9, 10, 11, 12, 13 from lower levels."

^ This could explain the brief pause at the 8th floor?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

BKNJ

They got out the front door.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Based on the deformation near the door frame in the unit 711 Ring video, I think it's very likely that anyone in the 11 stack, including 811 could have had difficulty opening their front doors. We do know that 111 and 611 got out so maybe it was some but not all doors.

Pretty clear that the failure and most commotion was originating along the 11 stack, so while some heard/felt the failing structure and escaped, maybe others heard/felt and were unable. The units further away from 11 would be hearing and feeling less and less before the collapse.

It's a pretty grim topic, not trying to overlook the tragedy for those involved.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (BKNJ)

Just curious, does anyone know what kind of doors they were?

According to the door schedule, the original doors were solid core wood with steel jambs. I read somewhere in meeting notes from the condo association that they were considering options for new unit doors, I think as part of the overall package they were starting when the building came down.
I'll have to see if I can find it again. Though I would think over 40 years they may have been replaced already, since condos like to upgrade common areas and corridors to avoid looking outdated.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Santos81)

You’re right on the money…no pun intended.

UPH required revisions to Foundation, Basement, Lobby, Second, and roof levels specifically for wind load resistance. The second floor framing plan with partial details and subtle but significant differences sticks out like a sore thumb. Legitimizes the rumors regarding a bought it yet to be obtained variance while simultaneously dismisses the suggestion the UPH was a later addition that wasn’t part of the original calculations.
I'm sure you've noticed the different signatures on the different 2nd floor framing plan drawings too. I've found 4 different S6 sheets in total.

Edit:
"simultaneously dismisses the suggestion the UPH was a later addition that wasn’t part of the original calculations."
Eh, not quite. There's still the possibility of fabrication shops having fabricated rebar cages off of the original unrevised copies.
Gotta love change orders.

The mess with the pile changes even, with changes up to 2 months before ground breaking. I'd put $100 on both the revised and unrevised copies being in workers hands on that site. If you're just referring to the engineering, then ignore me. #### Quote (Optical98) Demented Quote (Vance Wiley) I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor? "-1kPSI concrete for 9, 10, 11, 12, 13 from lower levels." ^ This could explain the brief pause at the 8th floor? I'd suspect differences in rebar being a more likely factor. You can hear the rebar in the 711 video under tension before the shearing failure began and before the cascading clapping of the collapse. S/T= and then refer to the charts. Additional compressive strength of the lower concrete definitely could have helped initially resist, or perhaps it could have been one of the assisting factors. There are those possible cold joints that SFCharlie pointed out. Would be amazing if we actually know which column that was and to which floor the photographed section belonged to. @Arbitraria Original doors. They were good, solid doors. Faux coverings were on the some of the interior of some doors. Edit: I just want to point out that that almost all of the approved rebar placement on the original construction and for renovations/repair work called for a minimum of 0.75" of spacing between rebar. If 1" was the code minimum spacing, I have two questions. 1) How did this get past everyone? 2) Why was this spacing allowed to continue on work through to permits as recent as 2010? This whole mention of not enough bar spacing in the columns is interesting. Unless they used 3/8" aggregate grain max on original construction, I'd suspect there to be a lot of voids in the concrete where water could collect and do it's magic work as the best universal solvent we know. That could even help hide full sections of rusted out bar as there'd be minimal to no spalling in those locations until it's too late. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 UPH. So, to me this feels like a low density low weight occupancy. Like a standard floor would have a lot more weight to it. To me the floor is open plan, less walls. The sides are also open. To me it doesn't feel like a big deal. Then again how many pancake collapses occurred due to floors added onto the design later? The thing is, its not like the roof had massive HVAC on it like that Korean mall collapse. But certainly this side of the building has smaller columns then the surviving. Plus those beams connecting the pool deck. But what pisses me off is the complete lack of security footage from the building, surrounding buildings, traffic intersections, the beach walks, the lane walk. Where is the footage? How do we literally have nothing? Nobody got any other angles? The hell man, this is some BS. Half the debates had in 11 threads would be resolved if just a video or two came out. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 @‘NEW’ SFCharlie, Just gotta ask! How is an ‘Old’ SF Charlie reborn as a ‘New’ SF Charlie on this Forum? Point being, I need some of that special elixr! ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Not disagreeing with Santos81 about pre-planned Penthouse based upon his observations, but it sure seems to be a real mess getting there. I have attached just one of Rodface’s sorted document packages, this one titled Structural 14 pages, and I will be first to admit, I may miss a lot looking at these PDF’s on a laptop, and not having the ability to print them out full size to really analyze well. 1 Please note page S12 shows elevator section view for a 12 story building and not have extended height middle section to allow UPH corridor tie in to main elevator shafts. 2 Then notice one of the S13 Beam Schedule ends at Beam 35 and another S13 goes to BM42 (which adds UPH and roof beams, as I remember) 3 Then S14A shows UPH, Corridor, and Elevator Section that has added vertical section to accommodate UPH. Typically you don’t add A revisions unless something has changed. Of course again, this could be way to play the game spoofing the building department or the local politics. I think I saw several UPH designs as far as whether it has it’s own dedicated elevator or the long corridor that connects to the main elevators. To me it sure looks like this was a 12 story building design originally, then a lot of under the table and trades were going on to try to find a way to scab a UPH cheaply onto 12 story design, and NOT that it was designed originally for UPH originally. I also wonder why, if you are doing the UPH for more bang for buck money, why did they not just have a full 13 story building with say 2 or 3 UPH units? Perhaps not enough money for full 13 stories or there was some concern or too costly to scab on a full 13th floor? Perhaps wind loading or some sort of loading issues? It also seems odd that they would stick UPH on the skinny column section, and not the beefy column sections, unless it was going to cut down on parking spaces and they needed more spaces? Does the larger garage columns have anything to do with the transfer beams in the lobby area and the eccentric loading of those columns or the floor to height spans of those columns required beefier column to resist buckling? Bottom line thinking to me, was the original Architectural Plan was for a 12 story building, but perhaps the developer was driving the train to scab on the UPH from early on, just had to release that scab at correct time? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (All About Money (Aerospace) 10 Aug 21 15:47) It also seems odd that they would stick UPH on the skinny column section, and not the beefy column sections, unless it was going to cut down on parking spaces and they needed more spaces? Two words. Ocean view. One other comment regarding the 904 survivor's statement. Note that was relayed thru a 3rd party, and may not be totally accurate. It's possible that stepped out the door COULD have meant the bedroom door, rather than the unit door. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 @Demented - I looked at the condo association's letter to the owners from April 9 of this year, their balance sheet had a special assessment from 2016 for unit doors in the amount of$252,000 - guessing that hadn't happened yet as the money still appeared to be in their reserves.

They also mention the association having as-builts on file, I wonder if there really was a set floating around out there like a mythical unicorn, or some sort of holy grail...more likely they cobbled together a set of plans over the years as they had repairs and upgrades done, then referred to those as such.

@AutisticBez - I believe Santos81 confirmed that investigators are in possession of better-quality (than what the public has seen) video from several angles, and I'm sure they have more than what he's mentioned. Anything with better resolution is going to show some pretty awful details, given that people were out on their balconies...understandable that they wouldn't release those to the general public. I don't know what the protocol is as far as this being a crime scene but I'm sure that factors in as well.

@AllAboutMoney - I think the location of the additional penthouse had almost nothing to do with the structure itself, far more to do with proximity to the ocean. Better views cost money, stands to reason they'd put the most expensive unit in the building in a spot that would justify charging even more for it.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (All About Money (Aerospace)10 Aug 21 14:47)

@‘NEW’ SFCharlie,
No magic here
Home>>Forums>>Engineering Forums by Industry>>Forensic Engineering>>Engineering Failures & Disasters Forum
click on "Failures & Disasters"
Scroll down to just under the ad
click Submit Post
Standback

Is this what you were asking?

I have a text file with all the previous threads and link
Oh Now you have a link to the new thread, go back and post a message in the old thread.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Another thing that never mad sense was the the thicker columns on the western side to hurricane proof the building. Wouldn't you want to hurricane proof the entire building?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Reverse_Bias (Electrical)10 Aug 21 17:31)

... thicker columns ...
The article I posted blamed the thicker columns on the valet parking ... Link

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

@SFCharlie, Thanks for responding. So New label means new member or new thread? Just curious?
I forgot about the Valet Parking Comment, thus I get the reason now! And duh, I get UPH was ‘All About Money’ and squeezing in one grand UPH Ocean View for Big Bucks!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Reverse_Bias (Electrical))

thicker columns on the western side to hurricane proof the building

That makes too much sense. Any thought about prevailing offshore winds at landfall in this? Where would the shear accumulate?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (All About Money (Aerospace)10 Aug 21 17:55)

New label means new member or new thread
I'm the same old SFCharlie as far as I know...

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (All About Money (Aerospace)10 Aug 21 17:55)

duh, I get UPH was ‘All About Money’ and squeezing in one grand UPH Ocean View for Big Bucks!
"The want of money is the root of all evil" ... the money's not evil, the want is...

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

why did they not just have a full 13 story building with say 2 or 3 UPH units?

Very simple.

13 residential floors in a 12 floor
/120’ Zoning District would have been automatically rejected.

(OP)

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer) (OP))

Emergency Works Taking Place This Weekend At Champlain Towers South Site

I think that's on hold waiting for permits. The irony....

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Like everything, there is always a cost (not necessarily monetary, e.g. loss of internal floor space) associated with over engineering anything. The strive is always to make it 'just good enough'. Anything else is wasteful.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Yeah but the cost of concrete and rebar is hardly your biggest expense compared to the entire building process and employing people onsite. A few inches here and there won't break the bank. I mean, you are spraying concrete everywhere, its surely not going to take much extra time.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Brainstorming - the structural mass of the thirteen story east wing starts to decompensate (banging noises etc.) (wind?) thus imparting a lateral load at the pool deck level (northward?) triggering the deck collapse and consequently resulting in the entire structural collapse.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

@AutisticBez - what you have to understand is that the cost of materials isn't really concerning anyone - the money behind these projects wants floor space to rent/sell in order to make the project maximally profitable. They can't rent floor space occupied by structure. The only people that hate columns more than Architects are Developers. To a lesser degree, structural depth in floor systems "works" the same way.

The bottom line is - money funds these projects and that money wants the maximum sellable/rentable space which implies minimum structural volume. From an engineering perspective, as RandomTaskk points out, anyone can design a structure that won't collapse under load - good structural engineers design the minimum (i.e. - usually the smallest or lightest) structure that does the job.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (All About Money (Aerospace)10 Aug 21 14:47)

@‘NEW’ SFCharlie,
NEW SFCharlie
is a NEW post by old SFCharlie

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer)(OP)11 Aug 21 15:18 Quote (All About Money (Aerospace)10 Aug 21 14:47) @‘NEW’ SFCharlie, I finally realized what you were asking about. NEW SFCharlie is a NEW post by old SFCharlie blush)

Nerd Humor is very hard to convey in text, emails and forums without a great picture or video. I definitely was Not an English Major!

I guess I was tripping over my do-dads?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Thanks SFCharlie. A lot of us were puzzled by that.

waross
Ohm's law
Not just a good idea;
It's the LAW!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Aug. 11, 2021, Update on NIST’s Champlain Towers South Investigation)

Still curious as to when, or what it will take, for investigators to learn the truth about the nature of the underground concrete piles.

I am unfamiliar with the amount of demolition that is performed when a site like this is to be redeveloped. Would all piles be fully extracted and the soil filled? Would they be left in place, and piles for the new construction have to work around these existing ones? I can't imagine that they would be re-used for the new construction in any way, shape, or form.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

To quote rodface: "...I can't imagine that they would be re-used for the new construction in any way, shape, or form..."

If I may share a story told to me by a person I worked with decades ago, so keep in mind I was not personally there. He grew up in Florida and before entering the military worked as a gofer for a construction company. According to his story, the construction crew would dig and place forms for slab homes. When several homes had their forms in place with the rebar set in for pouring the concrete, the inspector would stop by and verify the rebar in place and would sign off that the concrete was ready to pour. Then the foreman and the inspector would walk off and shoot the breeze and drink some coffee while the crew wrestled out the rebar to the next foundation and dropped it in. The inspector would walk over and sign off that the rebar was in place and the concrete ready to pour. Rinse and repeat for the block of homes.

The point of this story, if true, is that there may be other construction firms and inspectors who would use the same process, although I think with the scrutiny this tragedy will receive, I would consider it unlikely.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Concrete structures can support larger columns spaced further apart then this. These columns seem to be 2 car spaces in width and 1 long. In major parking garages here in Melbourne, you get them spaced 3 to 4 wide and 2 long. Obviously they are a wider column. We tend to see more of the round style columns.

Build it right. These people died due to excessive cost cutting by the developer right? Gotta make those columns super thin. You couldn't put enough rebar into them without compromising them further.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I think we agree in principle, but over engineering it is not the same as building (or designing) it right.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (NIST)

Geophysical methods that send very low intensity waves (e.g., impulse echo and ground penetrating radar) into the ground or the foundations will be used to obtain information about the condition of the foundation and its surrounding soil with minimal disturbance to the site conditions.
So... The are going to radar the foundation. ???

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (AutisticBez (Computer)11 Aug 21 19:32)

Gotta make those columns super thin. You couldn't put enough rebar into them without compromising them further.
Why no just make beautiful spacious columns?

???
Sorry, not a structural, mechanical, nor civil engineer...

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SF Charlie)

GPR at several wavelengths for rebar and for shallow voids and structures, Small scale seismic (MASW and/or refraction) for deeper investigation. If they have the time and the inclination they could build a 3D model of the subsurface that way, I assume they are just being thorough. Have we seen any indication a pile moved?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SF Charlie)

Why no just make beautiful spacious columns?

Modern construction methods for flat slabs use drop panels for increased shear strength at columns, which is basically what your nice-looking column sketch is getting at, but with less complex/expensive formwork and construction.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

After they're done with the "investigation", before anything else can be built on the site, I think at least the basin will have to be dug up and removed, honestly everything should go. They need new piping etc.
With having had the dynamite/implosion there is likely damage to the pilings.

And there will be too many eyes on that project to cut corners this time.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (AusG (Petroleum)11 Aug 21 22:44)

Have we seem any indication a pile moved?
Sadly, we haven't seen anything. I'll let you all know if I find out anything.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (rodface (Mechanical)11 Aug 21 16:21 Quote (Aug. 11, 2021, Update on NIST’s Champlain Towers South Investigation) Still curious as to when, or what it will take, for investigators to learn the truth about the nature of the underground concrete piles.)

If there is any record of the TOP ELEVATION of the pile caps a quick level survey could tell if there had been a foundation failure from a settling pile group and cap.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley )

Yes. For my money a physical survey of the pile caps would be more definitive than any geophysics. If they've moved relative to each other you can start to wonder why then.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Hello, -would like to state that I'm not an Engr.
Retired General Contractor/Construction Manager.
Been following the thread for quite some time, and have noted that there really has been no in depth discussion about storm water disposal (please correct/direct me if I'm mistaken).
From what I've read, around the time of CTS, Surfside was hurting $$for a stormwater disposal upgrade, and the developer fronted Surfside 200 grand so that he could get started with CTS (or something like that). Anyhow, what looks to me like early submittals (specifically P1 and P2) were marked up by the plumbing inspector. Stated that the Catch basin bubblers were inadequate and probably didn't like the French drain system and to go find an Engineer who could come up with a plan to satisfy Health Dept. and Pollution Control. Revised plans subsequently showed a storm water disposal injection well on the East(Beach) side. I have seen the 18" storm located in the garage along Col. line 8 in the video of the garage taken by the prospective buyer (note: slight jog in the line to accommodate Bm34). One can also see it in the aftermath video (WPLG Local 10) of the interview of Kilsheimer in which he says he's "...pissed off". To me it looks like the storm is around 3 ft. south of Col. line 8, and invert at wall penetration around the same el. as the bottom of Bm34 (which according to one of the drawings is +9'-10". The el. of the patio outside at that point would have been around +13', so really not too much cover. Please correct me if I'm wrong here. Any how, according to the drawing there were to be two 3,000 gal. retention tanks dumping into two 24" square wells, and a total of 8 - 24" manholes. I can't find 'em - before or after. Nor for CTN, but I see some (only 3) for CTEast which was built in '94 if I'm not mistaken. I think by that time they (the well or wells) would be Class 5 with a French drain filtration before the well for garage and planter contaminants. And any how, by my calc the wells drawn for CTS would have been around 17' from intake to centerline of well. That puts it pretty close to Col. Line 9.1/10. The drawing says, "Well depth as required to meet requirement of pollution control section of building dept." ???????? Any registered stamped records Surfside? Lotta water dumping down that hole. Well, anyhow, have a look yourselves. I have only seen a black round something at ground level by the entrance gate to the pool from the beach walkway. Interestingly, I believe that same area is ringed by several cones on the site grid map (Briefing Map) from 7/18/2021. It would also be very interesting to me if anyone could find info about the North building. Drilling records? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 SF Charlie - Your column looks suspiciously like the Frank Loyd Wright columns in the Johnston Wax Headquarters building. I will grant the are visually pleasing, but they pushed the limits of concrete construction way too far. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (FacEngrPE (Mechanical)12 Aug 21 10:26) the Frank Loyd Wright columns in the Johnston Wax (I didn't mean to claim any originality for the columns.) #### Quote (Wikipedia) In the Great Workroom, the columns expand from 9 inches (23 cm) in diameter at the bottom to "lily pads" 18 feet (5.5 m) in diameter at the top; skeptical building inspectors required that a test column be built and loaded with twelve tons of material. After the test column proved capable of supporting the specified load, Wright had the load progressively increased. Only at sixty tons load did any crack appear. SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Meh. If we have leg lamps, why can't we have leg columns? That'll sexy up buildings. Precision guess work based on information provided by those of questionable knowledge ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (Demented (Industrial)12 Aug 21 17:23) why can't we have leg columns? That'll sexy up buildings. ...an image would sexy up this thread... As for gracious columns... there's a business opportunity here. The forms rental companies could have standard modular graceful column forms. They could come in standard sizes. Also, they might be only for the top, so the contractor could customize the height. SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 2 #### Quote (SFCharlie) ...an image would sexy up this thread... As for gracious columns... there's a business opportunity here. The forms rental companies could have standard modular graceful column forms. They could come in standard sizes. Also, they might be only for the top, so the contractor could customize the height. Something like this. Precision guess work based on information provided by those of questionable knowledge ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Wonder who(m) will be groping inspecting those columns? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 I think we have a joint collapse theory that includes the roof and bottom collapse. The pool deck collapse caused the collapse of Beam A 's around column 11.1 as seen in TikTok video. This pulled on the column M10 and L10 and beam 33 and 35 and fractured the floor connections causing a torsion in the building and in the top levels of the building which collapsed and pancaked. The weaker floors started at level 8. The top heavy loads on the roof and the cantilevers and maybe more caused more eccentricity. The columns on the section at the parking garage under the uncollapsed section show the damage of just the floor shearing off. Thus it did not collapse. The columns were a little bigger but there was no beam there either which caused the initial failure and also saved that part from collapsing. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (raymiepo (Computer)) I too would like to understand Surfside’s Storm Drainage System, and was the 400K split all spent for on the system showing on P1and P2. If that is where Surfside’s 200K share went, then Surfside just gave the Developer 200K? After tub was dried out, the in rush with high tide seem to come from the West side of CTS, or from under Collins Stormwater system. So it would appear, it may be back flow from a flooded under designed street side system or just an old leaky system? Edit: It is hard for me to understand how the CTS storm water holding area would work with a higher water table and no where for water to go into well? Edit2: Where do you put storm water when water table is so high on flat near sea level islands? In our city frequent weekly 100 year rain events cause storm runoff to enter leaky sanitary sewer system and cause flooding of both in low areas. I am on a mountain, so the back flow never seems to reach my elevation, but what do u do in Surfside? Pump it back into ocean in a never ending battle? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Pump stations typically pump it out to the intercoastal waterway from east to west on the island side. A few threads back Santos81 was mentioning the pump stations being inadequate for that area. Up here in the Palm Beaches our pump stations go out quite regularly especially around times of heavy rain, I can only assume Miami-Dade is the same. They just simply are running all the time, but we do have enough redundancy built in that it's not; lessons from Irene. Precision guess work based on information provided by those of questionable knowledge ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 The attachment which contains the following statement may be applicable to the study of the storm drain system. #### Quote (An Overview of Urban Stormwater- Management Practices in Miami-Dade County, Florida ) Community Stormwater Management Design storms with 5-year return periods are required in the design of residential and commercial stormwater management systems, and full onsite retention of design storm runoff is required if at all possible (Miami-Dade Department of Environmental Resources Management, 1980). The implication of this requirement is that the stormwater management system must be capable of accepting runoff from 5-year storms of any duration. Five-year storms with a 1-hour duration typically are used in assessing the capacity of onsite drainage structures, such as exfiltration trenches. ... A cistern able to hold the rain from a 5 year storm (2.88 per 1 hour and 6.67 per 24 hours) is huge. These rules were placed into effect in in effect as of 1980, which was the construction year. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Demented) Something like this. #### Quote (All About Money) Wonder who(m) will be groping inspecting those columns? You just took me back to 1986. I was a minority hire into outside plant engineering at the phone company. I thought I had time traveled back to 1950. I won’t regale you with all the things my colleagues did to get me to quit. But their tactics didn’t work because I had decided that I would outlast them…and I did. After the black guys, the Korean-American guy, and the other white woman started at our office, I was ready to move into a different department. But before I left, my state president personally busted my boss’s boss for what he did to me, and my boss got transferred to a job he hated. Neither of them finished their careers at the phone company. Ah, those were the days! 35 years later, I would have thought we would have gotten a little farther than we have. If any of you have daughters who find themselves in a similar predicament, I hope they too will be sure to figure out how to get even instead of mad. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (MaudSTL (Computer)12 Aug 21 22:35) I personally apologize for provoking the continuation of this stream of thought. SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (FacEngrPE (Mechanical)12 Aug 21 22:05 The attachment which contains the following statement may be applicable to the study of the storm drain system. Quote (An Overview of Urban Stormwater- Management Practices in Miami-Dade County, Florida ) Community Stormwater Management Design storms with 5-year return periods are required in the design of residential and commercial stormwater management systems, and full onsite retention of design storm runoff is required if at all possible (Miami-Dade Department of Environmental Resources Management, 1980). The implication of this requirement is that the stormwater management system must be capable of accepting runoff from 5-year storms of any duration. Five-year storms with a 1-hour duration typically are used in assessing the capacity of onsite drainage structures, such as exfiltration trenches. ... A cistern able to hold the rain from a 5 year storm (2.88 per 1 hour and 6.67 per 24 hours) is huge. These rules were placed into effect in in effect as of 1980, which was the construction year.) Thanks FacEngrPE, that was an interesting read. So, if I did my math right, CTS should have been able to hold 51,593 gallons of rain locally, or handle the first 1" of rain fall from the 1.9 acre site. What CTS had was a 3000 gallon retention system that drained into a 24" box feeding an undefined well. So it appears to me, there is NO WAY CTS storm system is anywhere close to sufficient capacity to meet code requirements at the time.... Consistent with the trend for CTS. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (MaudSTL (Computer)) Maud, I did not mean to offend anyone with my comment, nor was there any intent to imply I condoned what you implied happened to you in 1986. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Ditto, apologies. suitably chastened. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) ...and speaking of "other weighty matters"... Another image from Dorte Mandrup's portfolio... Curved buildings are noted for their resistance to earthquakes because they are not excited by shaking in any one axis. To me, this image makes a statement that slender pillars can carry immense weight. Thank you, Maud, for returning my focus to columns that can help protect against slab shear punch-through. SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (MaudSTL) You just took me back to 1986. I was a minority hire into outside plant engineering at the phone company. I thought I had time traveled back to 1950. I won’t regale you with all the things my colleagues did to get me to quit. But their tactics didn’t work because I had decided that I would outlast them…and I did. After the black guys, the Korean-American guy, and the other white woman started at our office, I was ready to move into a different department. But before I left, my state president personally busted my boss’s boss for what he did to me, and my boss got transferred to a job he hated. Neither of them finished their careers at the phone company. Ah, those were the days! 35 years later, I would have thought we would have gotten a little farther than we have. If any of you have daughters who find themselves in a similar predicament, I hope they too will be sure to figure out how to get even instead of mad. Apologies for any offense. I've got unicorns and rainbows all over my station of pink painted tools. No offense was intended at all, trust me. Precision guess work based on information provided by those of questionable knowledge ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (All About Money) Thanks FacEngrPE, that was an interesting read. So, if I did my math right, CTS should have been able to hold 51,593 gallons of rain locally, or handle the first 1" of rain fall from the 1.9 acre site. What CTS had was a 3000 gallon retention system that drained into a 24" box feeding an undefined well. So it appears to me, there is NO WAY CTS storm system is anywhere close to sufficient capacity to meet code requirements at the time.... Consistent with the trend for CTS. Ocean to the East, Intercoastal waterway to the West. Retention systems requirements kinda get altered around those. I am not sure as to which extent that is allowed, but it is a factor that could actually put the retention system in spec with the fault being on the towns side of the system. Where I'm at, we have swells that feed into a retention pond that overtops into culverts that drains straight into the intercoastal. Roughly a 45 acre property with 80k gallon or so retention pond. *shrugs* ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote: Sec. 34-43. - Design standards. To comply with the performance standards set forth in this division, the proposed stormwater management system shall conform to the following design standards: (1)Detention and retention systems shall be designed to comply with the Stormwater Management Manual adopted by Dade County. (2)To the maximum extent practicable, natural systems shall be used to accommodate stormwater. (3)The proposed stormwater management system shall be designed to accommodate the stormwater that originated within the development and stormwater that flows onto or across the development from adjacent lands. (4)The proposed stormwater management system shall be designed to function properly for a minimum 20-year life. (5)The design and construction of the proposed stormwater management system shall be certified as meeting the requirements of this article by a professional engineer registered in the state. (6)No surface water may be channelled or directed into a sanitary sewer. (7)The proposed stormwater management system shall be compatible with the stormwater management facilities on surrounding properties or streets, taking into account the possibility that substandard systems may be improved in the future.(8)The banks of detention and retention areas shall be sloped to accommodate, and shall be planted with, appropriate vegetation. (9)Dredging, clearing of vegetation, and deepening, widening, straightening, stabilizing or otherwise altering natural surface waters shall be minimized. (10)Natural surface waters shall not be used as sediment traps during or after development. (11)Water reuse and conservation shall, to the maximum extent practicable, be achieved by incorporating the stormwater management system into irrigation systems serving the development. (12)The grading of all properties located west of Collins Avenue shall be designed so that the average grade elevation of the lot, other than the building's footprint, shall not exceed the average elevation along the center line of the street pavement on which it fronts. Proposed elevations along the property boundaries shall match the adjacent lands, and cause no storm water runoff to flow across any of the property's boundaries, as provided in subsection (3) above. (13)A Florida Registered Professional Engineer shall provide certification of conformance with these design standards of the project's grading design at the time of submittal for approval of construction documents, at completion and prior to occupancy. (Code 1960, § 6B-27(b); Ord. No. 1442, §§ 1, 2, 9-9-03) @All About Money It does appear CTS was in complience. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Optical98) That is all still one of the more concerning aspects of all of this to me. The structural consultant was being paid >500K to inspect and analyze the integrity of the building, and design the repairs for it and had been working on this for several years. Either the flaw that allowed this was so hidden, or they should have seen it. Or was this like FIU where it was staring everyone right in the face but they didn’t want to acknowledge it? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Insurance companies doing what insurance companies do best. They love taking your money, but always find ways to not pay out their own. I don't see how the insurance companies can refuse to cover the engineer at this point, until the cause of the collapse is better identified. Even then, Morabito didn't have control of the timing when the work got done, and based on the evidence out there in terms of visible surface damage, there was no precedence to believe this building faced an imminent collapse. Perhaps they share some liability, but they did not design, build, or maintain the structure that collapsed. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (The Palm Beach Post) The commission voted unanimously to pursue legal action against Miami-Dade County, the court-appointed receiver for Champlain Towers South, and any other entities that are preventing the town's hired expert — Allyn Kilsheimer of KCE Structural Engineers — from accessing the site where the collapse occurred, as well as from the warehouses where debris from the site is being stored. Surfside condo collapse: Once together in mourning, Surfside now fuming; aims to sue county SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Civil/Environmental) Insurance companies doing what insurance companies do best. They love taking your money, but always find ways to not pay out their own. I don't see how the insurance companies can refuse to cover the engineer at this point, until the cause of the collapse is better identified. Even then, Morabito didn't have control of the timing when the work got done, and based on the evidence out there in terms of visible surface damage, there was no precedence to believe this building faced an imminent collapse. Perhaps they share some liability, but they did not design, build, or maintain the structure that collapsed. Not the building itself. There was reason to believe the pool deck could collapse at any moment. That alone could have been fatal if someone were under it. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 In a geographical area such as this one. is the prevailing notion with regard to stormwater management more or less "meh"? Only designing for a 5-year storm seems insane to me, but I'm in the northeast (land o'regulations, I suppose) so the natural conditions are a wee bit different. I realize the coast and bay are in close proximity to the CTS site - in a big storm / hurricane situation, is it just a given that the stormwater will converge with those bodies of water, so any attempts at large-scale diversion are futile? I'm trying to get an accurate gauge for what is standard in this area, the system seems undersized but again these environmental conditions diverge from what I'm used to. Can a well of indeterminate depth adequately accept so much discharge? Such a narrow strip of land relative to all that water has to be under a decent amount of subsurface pressure from all sides, it just seems like there wouldn't be anywhere for this water to go. The outlet's proximity to the structure feels like an invitation for trouble. If stormwater can't adequately discharge, just how backed up would all of those drains get? Aside from obvious issues at the base of the structure, is it possible that there was a pressure/leak condition inside the walls from the rain water leaders? I have to go back and re-read the articles that describe the developers' contribution to the town's utility upgrades - I had assumed sanitary when they talked about insufficient sewer capacity. If it was in fact stormwater, CTS had to pay to get the town's system up to date to allow for development, but they never actually had to connect to it? It makes sense that allowing for higher-density structures would necessitate a larger system, I'm just baffled that at least one of these towers would then be exempt from integration. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 2 For those interested in info about CTS injection well > Interactive map for: Underground Injection Control (UIC) Class V Non-ASR Wells (ASR) Aquifer Storage and Recovery. https://ca.dep.state.fl.us/mapdirect/?focus=uic A couple of things I've discovered: 1. CTEast has two wells. 2. Mirage on the Ocean, 8925 Collins Ave, has one for stormwater drainage with a construction complete date of 01/13/1982. 3. Surf Club, 9011 Collins Ave, has one for swimming pool drainage with a construction complete date of 06/07/1977. 4. CTSouth and CTNorth have none showing on the map. 5. Wells, in the area, are around 80 to 90 ft. deep. I will note that there is a disclaimer: "The existence and accuracy of the point locations are being verified. Positional accuracy may vary from feature to feature. Information contained herein is provided for informational purposes only. The State of Florida, Department of Environmental Protection, Bureau of Water Facilities Regulation, Underground Injection Control Program, provides geographic information systems (GIS) data and metadata with no claim as to the completeness, usefulness, or accuracy of its content, positional or otherwise. The data could include technical inaccuracies and typographical errors." My questions now are: Did CTS ever have permitted, inspected, and recorded wells as drawn on the plans? Where/into what did the 18" storm for CTS discharge? Does CTN have permitted, inspected, and recorded wells? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (SFCharlie (Computer) (OP) 13 Aug 21 15:43 Quote (The Palm Beach Post) The commission voted unanimously to pursue legal action against Miami-Dade County, the court-appointed receiver for Champlain Towers South, and any other entities that are preventing the town's hired expert — Allyn Kilsheimer of KCE Structural Engineers — from accessing the site where the collapse occurred, as well as from the warehouses where debris from the site is being stored. Surfside condo collapse: Once together in mourning, Surfside now fuming; aims to sue county) This is a very disturbing article and makes you wonder if we will ever get definitive answers as to why the building collapsed. Hopefully this legal pressure from Surfside will result in Kilsheimer gaining access to the site and debris, but the truth is he should have been on site throughout the entire debris removal operation. If this had been done properly we would probably already know the cause of the collapse and appropriate action could be taken. As it is, the debris/evidence has probably been disturbed and compromised to the point where getting definitive answers about the collapse may no longer be possible. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (raymiepo (Computer)13 Aug 21 16:50 For those interested in info about CTS injection well > Interactive map for: Underground Injection Control (UIC) Class V Non-ASR Wells (ASR) Aquifer Storage and Recovery.https://ca.dep.state.fl.us/mapdirect/?focus=uic A couple of things I've discovered: 1. CTEast has two wells. 2. Mirage on the Ocean, 8925 Collins Ave, has one for stormwater drainage with a construction complete date of 01/13/1982. 3. Surf Club, 9011 Collins Ave, has one for swimming pool drainage with a construction complete date of 06/07/1977. 4. CTSouth and CTNorth have none showing on the map. 5. Wells, in the area, are around 80 to 90 ft. deep.) Very Interesting. I notice on your link that 87 Terrace has no less than 12 wells surrounding their property. One or two are listed in Surfside but most are listed in Miami. Point being 87 Terrace has the ability to shed a lot of water fast compared to anything in Surfside area. I checked and the articles do say CTS Developer contributed 200K towards Sewer improvements and not storm water drainage. The deepest well I saw around CTS and 87 Terrace was 136 Feet Edit: Collins Ave has 4 wells between 88th and 87th along the front of CTS. So a lot of water is being dumped deep underground on two sides of CTS. Edit2: The 3 Collins Ave Wells in front of CTS were drilled in 1994. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 > Hopefully this legal pressure from Surfside will result in Kilsheimer gaining access to the site and debris There's very little left at the site, giving him access now is pointless. Although one point of interest (re condition of piles discussion above) is that afaik they never tried to break up or get under the basement slab. That implies to me that they aren't concerned about what's underneath and don't think that had anything to do with the collapse. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 All About Money, for what it's worth, a lot of those wells for 87 Park were for dewatering. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 @arbitraria Some fun info in there on the towns storm drainage plans. Pretty much, just pump it into the bay faster than it comes in. https://www.townofsurfsidefl.gov/docs/default-sour... https://townofsurfsidefl.gov/docs/default-source/d... https://www.townofsurfsidefl.gov/docs/default-sour... https://www.townofsurfsidefl.gov/docs/default-sour... Precision guess work based on information provided by those of questionable knowledge ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 @raymiepo, Looking at the storm drainage link you provided, the Four (4) 2016 wells along the East Beach Side of 87 Park are De-Watering wells, 1 of the other drainage wells is a 1984 Vintage Well, and the other 7 are 2017 Vintage Drainage Wells. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Just found two more security cameras on the pool deck. Unlike the two cameras found by Kreemerz in Part 2, which appeared to look south directly over the pool area and east to see people approaching the gate to the pool area, these two cameras appear to look south over the pool deck between the pool and the parking area and east to see people approaching the doors to the stairwell and the gym room. Both of these latter cameras should be positioned to see any collapse of the pool deck and provide a time stamp, with the latter camera also being able to see if the collapse started on its own or as a result of an object dropping from the roof onto the patio area outside room 111, under which the objects in the TikTok video were seen. If the tapes from these two cameras are not made available to investigators, and eventually to the public, then the absence of these tapes would need a good explanation. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 All About Money, you're a better man than I. fyi: clicked on the "?" (Help Documents and Contact Information)at the top center panel of the link. I shot an email to the GIS.Librarian. Asked how far back the data/information dates. Got a very quick response by a very cordial Training Lead at the Help Desk. Response included that the layers on that map represent all the UIC Wells in Florida so there isn't really a date range set for the map. so my focus of interest remains: Did CTS ever have permitted, inspected, and recorded wells as drawn on the plans? Where/into what did the 18" storm for CTS discharge? Does CTN have permitted, inspected, and recorded wells? ps: pertaining to 87 Park > did you ever see this link by the historic preservation community provided by the townofsurfsidefl ? https://www.townofsurfsidefl.gov/docs/default-sour... ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Quote (raymiepo (Computer))so my focus of interest remains: Did CTS ever have permitted, inspected, and recorded wells as drawn on the plans? Where/into what did the 18" storm for CTS discharge? Does CTN have permitted, inspected, and recorded wells?) ] raymiepo, I too would like your questions answered. It appears CTS N and S might have gotten a pass on storm water system. You are the first to really research this area. We know the site did not drain well, so it appears the water just sat on top of roof and patio slab? We know storm drainage pipes were replaced in garage a couple of years ago with PVC, and cast iron may have been in real bad shape. Plus I have read the plants had root snakes up to 12 foot long in the drainage pipes. It could be there is a 3000 gallon tank underground but perhaps the well was never installed? The Collins Street Wells were done by FDOT in 1994, I think. Or perhaps CTS was tied into some sort of Surfside Storm Drainage System in 1981, that was abandoned when FDOT updated Collins Ave? But that does not mesh with the 18" pipe thru the east wall of the tub. I have actually seen the historical link concerning construction of 87 Park. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) Found it! Photo of CTS flood water disposal system: SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 https://www.youtube.com/watch?v=WaZcyq7YsNA This video has no mention of tar kettles, things falling from the roof or drainage issues. WHAT IS HE HIDING!! ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 @Demented, thanks for those links! Definitely a different set of environmental factors than I'm used to. Does FDEP have teeth as far as permitting and enforcement? That may sound like a silly question, but it appears from the outside that FL has been kind of a regulatory wild west until something exceptionally egregious occurs that forces oversight (Andrew, hopefully CTS, etc.). I'm sure plenty of states put on a good show that don't actually do much...then there are states like mine that can be a massive pain to deal with. (I'm grateful for the environmental protections, but talk about persnickety reviewers... One project I worked on over the course of several years had 3 running sets of drawings at any given moment - one regular project set, two separate DEP permitting sets, all in different permutations of 3 design phases that had been split into sub-phases, which had to be integrated into different sub-phases for the permit sets...I honestly don't know how I kept it all straight. That one broke my brain a little.) I know a lot has changed over 40 years, but the relative absence of depth on the site plans for this property is just bizarre. Any additional angle just brings more and more questions. I hope the association, at the very least, had better information in the form of their as-builts. I suppose there could be one bright side to the drainage issues - maybe a lot of that water CTS was accumulating in the garage wasn't saltwater after all! So, hooray for potentially slower corrosion? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Nukeman948 (Electrical) 14 Aug 21 01:39) As I stated earlier... He does a fine job of laying it out. And to carry on, the pool deck collapse, initiated at the car park, was retarded by the stiffening offered by the beams and slab steps as it reached the 11.1 grid line ... for maybe 5 minutes or so. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (SFCharlie (Computer)(OP)14 Aug 21 01:28 Found it! Photo of CTS flood water disposal system:) What would you call that 'Column' of Water in your image? Building Integrity for the Win? Still does not explain first collapse heard near elevators? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Nukeman948) This video has no mention of tar kettles, things falling from the roof or drainage issues. WHAT IS HE HIDING!! I don’t know how he gets any real work done. Or maybe it’s that simple. In which case why didn’t the consulting engineer hired to complete a structural analysis pick up on any of this? How do you design repairs for a building if you haven’t identified what is wrong with it in the first place? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 3 Solid analysis by Building Integrity. Would like to learn more about his calculations showing that the pool deck was designed at 100% capacity with dead load, and whether that considered additional loading from the topping layer, sand layer, and pavers, along with planter beds containing water saturated soils. His identification of the two 12"x16" columns at the edge of parking as a weak link, makes complete sense as a likely origin of the failure. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Put together, MarkBob2's latest image and high water levels raise the intriguing possibility the failure was triggered by the collision of two submarines in the parking garage. No wonder there is a air of secrecy around the site. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Got this from a twitter post. The article is behind a paywall so I just have the graphic. It shows a lot of overloaded columns in the section that collapsed. Plenty of the same columns the Miami Herald article marked in red for overcrowding. Although it doesn't show the pool deck I think it's irrelevant cause that was all punching shear failures except for M11.1. https://twitter.com/XinzhengLu/status/142612984022... Edit: Some users have pointed out this study may have some issues and used an out of date column schedule. Columns that were this overloaded probably would have showed obvious signs of cracking and buckling years before collapse. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Spartan5) I don’t know how he gets any real work done. He seems to stay focused on the real issues instead of chasing all the rabbits to check out their holes. #### Quote (In which case why didn’t the consulting engineer hired to complete a structural analysis pick up on any of this?) Maybe they did, weren't they planning to redo this area as part of the pool deck repairs? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (arbitraria) @Demented, thanks for those links! Definitely a different set of environmental factors than I'm used to. Does FDEP have teeth as far as permitting and enforcement? That may sound like a silly question, but it appears from the outside that FL has been kind of a regulatory wild west until something exceptionally egregious occurs that forces oversight (Andrew, hopefully CTS, etc.). I'm sure plenty of states put on a good show that don't actually do much...then there are states like mine that can be a massive pain to deal with. (I'm grateful for the environmental protections, but talk about persnickety reviewers... One project I worked on over the course of several years had 3 running sets of drawings at any given moment - one regular project set, two separate DEP permitting sets, all in different permutations of 3 design phases that had been split into sub-phases, which had to be integrated into different sub-phases for the permit sets...I honestly don't know how I kept it all straight. That one broke my brain a little.) I know a lot has changed over 40 years, but the relative absence of depth on the site plans for this property is just bizarre. Any additional angle just brings more and more questions. I hope the association, at the very least, had better information in the form of their as-builts. I suppose there could be one bright side to the drainage issues - maybe a lot of that water CTS was accumulating in the garage wasn't saltwater after all! So, hooray for potentially slower corrosion? FDEP does have teeth. Based on personal experience however, a small stack of dead presidents is enough to keep the muzzle on. It's easier to ask for forgiveness than to ask for permission. There's a lot of good agents on the ground that try to do right, don't get me wrong, the issues are just higher up. A lot has changed in the 40 years yeah, but a lot of what I see on the ground is still the same. If you think the paperwork is a mess, you should see how we drive on our roads down here. #### Quote (Nukeman948) Maybe they did, weren't they planning to redo this area as part of the pool deck repairs? Yes they were. Roughly 18,000sqft of upper decking and slab were being looked at for full depth replacement or at the very least, partial depth repair. Roughly 14,000sqft of the decking was replaced/repaired in 1995/1996 and this work was known to contain a lack of rebar, improper work in general, and was never completed. I still don't think anyone thought the deck would fail as it did, but they wanted to get the ball rolling on that work long before they even started on the roof work. #### Quote (CE3527) Solid analysis by Building Integrity. Would like to learn more about his calculations showing that the pool deck was designed at 100% capacity with dead load, and whether that considered additional loading from the topping layer, sand layer, and pavers, along with planter beds containing water saturated soils. His identification of the two 12"x16" columns at the edge of parking as a weak link, makes complete sense as a likely origin of the failure. 14,000sqft of the pool deck was not as originally built. So the loading on it was actually far worse. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Nukeman948) Maybe they did, weren't they planning to redo this area as part of the pool deck repairs? It’s not to say that they aren’t there, but I don’t recall seeing the proposed installation of transfer beams or other modifications that mitigated the potential for punching sheer at the pencil thing columns. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Spartan5 - they're not there. The morabito plans only called for removing the topping at the pool deck, repairing whatever cracks they find, and then installing a new topping (and waterproofing). They called for some more significant structural alternations along the driveways into the at grade parking. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Reverse_Bias (Electrical)14 Aug 21 06:58 Got this from a twitter post.) Interesting presentation. Thanks for posting. If we the "axial compression force ratio" is correctly determined and presented it seems to mirrors the initial collapse quite well. Same caveat, we can see that the Penthouse addition was not the whole and complete cause. A "load Ratio" of 1.89 has probably [1 floor added/13 floors total] = maybe 8 % Penthouse and was [1.89-.08] = 1.81 "Load Ratio" to start with. Of course we do not yet know if this is actual load and ultimate column capacity or factored loads and some % of ultimate column capacity. But either way it is bad news and the "load ratio" as presented seriously exceeds codes and good practice. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (AusG (Petroleum)14 Aug 21 06:19) collision of two submarines in the parking garage ...at least they weren't flying submarines that landed on the roof... Count your blessings SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 I think Building Integrity makes a great point. The decision to remove the one foot step between top parking area and pool deck is significant. Which removes a massive 21 inch beam that would have run north south under the planters. You then have the cars positioned right there as well. The pool deck was probably fully loaded and it only took a single failure to kick this off and it progressed into the building, which had 16 inch columns. Pool deck collapse is the start. And the weakest point of the pool deck is under this carpark, where multiple tonnes of car are parked on it. We have the weak point here. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Vance Wiley (Structural)14 Aug 21 17:53 Quote (Reverse_Bias (Electrical)14 Aug 21 06:58 Got this from a twitter post.) Interesting presentation. Thanks for posting. If we the "axial compression force ratio" is correctly determined and presented it seems to mirrors the initial collapse quite well. Same caveat, we can see that the Penthouse addition was not the whole and complete cause. A "load Ratio" of 1.89 has probably [1 floor added/13 floors total) = maybe 8 % Penthouse and was [1.89-.08] = 1.81 "Load Ratio" to start with. Of course we do not yet know if this is actual load and ultimate column capacity or factored loads and some % of ultimate column capacity. But either way it is bad news and the "load ratio" as presented seriously exceeds codes and good practice.] So does column load ratio typically take into account the secondary moments too, in what appears to be a sway-frame RC Design for at least the collapsed portion, in at least the E-W direction? Although it would appear to me, that the lateral displacement would be worse at 2nd floor due to patio deck providing lateral support to the first floor of the building. Edit: I may have found the answer to my question. It appears if designer decided this was a non-sway frame design, then he would not have looked at secondary moments on slender columns, like you rwould in a sway-frame design. Now it appears this building is part non-sway frame and part sway-frame design to my untrained eyes? However Wind Loading is yet another loading calculation, and perhaps that would affect sway-frame loading too? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Watching the crane collapse video, it seems like this general planter area really was in the wars. The crane 'collapse' appears to have dropped the elevator wall formwork onto the deck, bending over the column starter bars on Grid L8. The crane itself seems to have dropped down onto M10 where one can see the planter beam formwork (in other portions of the video). On the way down it also damaged the 2nd floor cantilever balcony at J14. The west portion of the building appears to have been a floor or two ahead of the east. One wonders exactly where the pour joints were, possibly the podium deck was tied into columns J13, J14 and J15 later. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (All About Money (Aerospace)) #### Quote (So does column load ratio typically take into account the secondary moments too) Using numbers to allow focus on any particular part. 1) It certainly should address moments. However the graphic plan is titled "axial compression Loads" and that implies the moments may not have been addressed in this study. 2) Design for RC columns should address some minimum incidental moments, such as perhaps 5% of column dimension - perhaps 10%. As addressed prior, the shear walls are minimal at best and act in one direction only. The columns should have been designed for hurricane winds and that induces moments in the columns. 3) A lateral design with columns resisting shears from wind or seismic generally creates a point of inflection in columns that is at about the mid height between floors so shears in the column create (lets say) clockwise moments above the slab and likewise below the slab, and those additive moments have only a slab for resistance in this flat slab system. 4) The flat slab has column strips with reinforcing concentrated in those strips and which act as beams to support loads and moments. The cantilevered balconies provide negative moments at exterior columns to balance some of the loads from within the building. There are conditions where a c olumn exists at the edge of the floor area without a balcony, and the negative moments from the slab have only the columns for resistance. So the vertical load only can induce moments in the columns due to unbalanced floor loadings or locations, and the reinforcing must be detailed for development - and this can be difficult in thin slabs. 5) it appears this building is part non-sway frame and part sway-frame design As you stated correctly, in one direction it has some help from shear walls (not much tho) and in the other, the columns are all there is. And yes, the wind load design is additive and impacts the design of columns and slabs. Thus the beefed up reinforcing for the Second Floor slab due to the addition of the Penthouse. If this happened in calm winds, think what the next hurricane could have done. Thank you, ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Vance Wiley (Structural)) Thanks Vance Wiley, for answering my questions and explaining it very well. I realize it will take a detailed simulation to fully understand all the interactions of the individual components and the affects on the overall structural system, and connections. However, in my mind it seems this under nourished design allowed excessive movements of the structure, which it seems would just get worse with time and daily environmental load stress, live load changes, lack of proper maintenance and repair, etc. It seems to me that the swaying from vibrations that was complained about by the association was the wake up call that something was really wrong, and had to be addressed immediately. I can't imagine even the least nerdy person not realizing something was bad wrong and letting it go unaddressed was just doing more damage every day. Being a retired engineer, I know if my house was swaying from storm winds or whatever, I would be all over temporary bracing the structure ASAP, to prevent further damage cycles or collapse, until such time I devised a permanent solution. But then I am the owner, the bank, the engineer, and the skilled and unskilled laborer on my project home.... So there is no passing the buck option. The house I am in now, had a deck racking problem when I bought it, which I easily solved with a diagonal lateral brace screwed to the bottom of the deck joists. I chose this approach because the upper deck was over a lower deck, and diagonal bracing would have blocked the view from the lower deck. You would surely think the Association made Morabito aware of the sway issue, yet nothing in the certification plans seems to address that priority one issue? It also seems to me, Morabito should have done calculations based upon design drawings to determine loads, in order to be able to design repair solutions? It also would seem that a simple laser light level set up or a survey in the garage would have paid back in diamonds of value to evaluate the basement structure condition as far as deformations or variations in floor slab and beams. And that was very doable without kicking cars out of garage. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Quick question. Does anyone know what concrete restoration work was being done in August of 2019? Precision guess work based on information provided by those of questionable knowledge ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (All About Money (Aerospace)14 Aug 21 02:56) What would you call that 'Column' of Water in your image? This is more my idea of a fluid column... The Serpentine Sackler Gallery - Zaha Hadid Architects - ArchDaily Thank you Zaha Hadid, may you rest in beauty and peace! SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Yikes. Hope I don't have nightmares tonight. spsalso ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Champlain Towers stood for 40 years. Imagine if it were a cathedral, it wouldn't even be 1/4 built yet after 40 years. https://en.wikipedia.org/wiki/Sagrada_Fam%C3%ADlia ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (spsalso (Electrical)15 Aug 21 03:16) Hope I don't have nightmares tonight. Luckily, I didn't have to do the structural analysis... SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (SFCharlie (Computer)(OP)15 Aug 21 15:28 Quote (spsalso (Electrical)15 Aug 21 03:16) Hope I don't have nightmares tonight.) Logical follow-on question is how do you design SFCharlie’s fluid/elastic columns in one direction, yet use a more rigid shear wall in the other direction/plane without some sort of flexible or adaptable isolation coupling in sway frame direction with shear wall? It seems the fluid movements in one direction would be constantly clashing with the braced direction. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 (OP) #### Quote (All About Money (Aerospace)15 Aug 21 15:44) Logical follow-on question is how do you design SFCharlie's I don't think the columns are flexible, but if you would prefer something easier to calculate... Spikey - AD Classics: Vitra Fire Station / Zaha Hadid #### Quote (archdaily) Although Zaha Hadid began her remarkable architectural career in the late 1970s, it would not be until the 1990s that her work would lift out her drawings and paintings to be realized in physical form. The Vitra Fire Station, (1989) SF Charlie Eng-Tips.com Forum Policies ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 2 #### Quote (All About Money) #### Quote (fluid/elastic columns in one direction, yet use a more rigid shear wall in the other) The 'fluid/elastic' columns are in London, worst seismic recorded is 3.9. When concrete goes fluid it has fractured and it is all over. Lots of confinement reinforcing is needed to keep the concrete inside the reinforcing cage. As to how the building reacts, todays practice is something like lay out all lateral resisting elements, locate the center of rotation (CG) , and design for the direct load at whatever angle and add the rotational effects. Neglect any negative contributions if they reduce the direct load in a column or wall. Lateral loads are estimated based on the seismicity of the site and building mass, and applied at the center of mass for each level. The load is applied at some minimum distance from the CG if that minimum exceeds the actual eccentricity. The minimum is a percentage of the building dimension in the direction being considered. Today's seismic designs limit the amount of rotation allowed, with the effect of requiring designs with less rotation and more uniformity and/or symmetry in the lateral system. In he case of CTS, the shear walls were a boundary for the immediate collapse. So lateral forces were not a great factor - it fell pretty straight down. However, for loads parallel to the shear walls, there would have been considerable eccentricity for the east wing, which collapsed. The floor slabs would have acted as cantilever diaphragms extending from the shear wall to the east, to provide N-S stability while the shear walls remained more or less intact. The museum 'fluid/elastic' columns likely have different stiffness in each of the possible different directions and with rotation each column is loaded at a different direction. That makes my head hurt and the accounting department goes nuts when they see how much time is required to design for all that. Thanks,, ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (SFCharlie (Computer)(OP)) I realize the design of the fluid shape of those rigid columns would require ‘Cocaine Cowboys’ or Jeff Bezo Deep Pockets Level of Funding. #### Quote (Vance Wiley (Structural) I am getting the impression the sway movements residents complained about were driven by column movements and perhaps long term deformations causing load redistributions. With the interior columns being heaviest loaded, it makes sense for the middle of initial collapse area to drop first perhaps and pull perimeter inward. Which makes you wonder if the building started the collapse? ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (All About Money) #### Quote (wonder if the building started the collapse?) There does not seem to be any report of something unusual - no seismic activity, no hurricane, no impact from large vehicles or airplanes, no Heavens opening and large lightening bolts - just another day in the life of a 40 year old building. The graphic presentation with the "axial compression force ratio" information does suggest highly loaded columns in some areas and therefore lesser impacts could initiate failure. And the most highly loaded columns seem to be where the collapse started. Starting with excessive demand/capacity ratios and overlaying 40 years of coastal environment exposure and inadequate maintenance leads us to today. It will be interesting to see if the "axial compression force ratio"s withstand the coming analysis. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Vance Wiley) If the "axial compression force ratio" is correctly determined and presented it seems to mirrors the initial collapse quite well. It can’t be correct as it’s using an incorrect and incomplete column schedule. Seems a bit misleading; more of a propaganda statement than an actual forensic analysis. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Santos81) Shucks. Shows the need to verify sources and basis before proceeding any further. Propaganda - the medium which carried it suggests that. Thank you, ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Attached is the Full paper titled 'A preliminary analysis and discussion of the condominium building collapse in surfside, Florida, US, June 24, 2021' August 2021 Frontiers of Structural and Civil Engineering DOI:10.1007/s11709-021-0766-0 Authors: Xinzheng Lu at Tsinghua University Hong Guan Hailin Sun Yi Li ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Vance Wiley) Shows the need to verify sources and basis before proceeding any further. I found the doesn’t meet Chinese Code GB50010 (which the calcs are based on) to be the reddest herring follows by the inclusion of Type B columns, etc etc. #### Quote (All About Money) Attached is the… Might want to run a thorough and up to date Mal-ware scan. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (Santos81 (Specifier/Regulator)16 Aug 21 00:58 ) #### Quote (Might want to run a thorough and up to date Mal-ware scan.) Well I ran a scan on attachment for you Windows Fans, and it came back clean.... One advantage of using a Mac. I used Bit Defender which looks for PC and Mac Malware. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 Given all the educated middle class and CCP-connected folks who have their savings and lives invested in hastily-built concrete apartment towers I'm not surprised there is great interest in seeing a reassuring study separating this building from those that several hundred million people live in. ETA: I think this paper does that without claiming any greater knowledge. I see an email contact listed for the corresponding author. If there are documentable errors it would improve the next stage of their work to correct them. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 #### Quote (All About Money (Aerospace)15 Aug 21 23:55) "We acknowledge that this work is a preliminary study. The analyses and conclusions of this work are based on the available information with certain assumptions and simplifications. As such, the study outcomes are not anticipated to be used directly for forensic analyses or any other technical purposes. The intended purpose of this work is to provide a reference base for the forthcoming detailed forensic analyses and discussions of the cause of the failure of the Miami condominium building" I don't think there is any pretense about the substance of this paper. It suggests that certain columns are inadequate, that the east wing of the building lacks shear resistance and lays out their method of analysis. If someone can improve on this, I'm all ears. ### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11 A question about groundwater and water tables near the coast, please. It seems to me the sea level (average) would set the depth to water at the site of the CTS. And likely for some distance depending on the soil/sand/rock found inland. After a few million years everything should be sea level?? So what good does a 24" x 24" well do? I can see perhaps extending it 40 feet above the water table but that creates very little storage volume and flow is likely quite slow. A comment, anyone? I can see the benefit of injection of fresh water to push back on the salt water. And are they someday going to need a sea wall around Miami and locks to pass ships to the docks? There seems to be concern in San Francisco about enough fresh water flowing into the bay to keep the salt water out. It seems that a dam and gates and one way valves under/near the Golden Gate Bridge could be an answer. Big$$ I know but locks might not be needed - there is no change in elevation, just a double gate section for ships.
But SF is a continent away from CTS.
Thanks ,

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Vance Wiley (Structural)16 Aug 21 16:18)

concern in San Francisco about enough fresh water flowing into the bay to keep the salt water out
San Francisco would do better to drill a tunnel from their Oceanside Water Pollution Control Plant to the bay and dump their fresh treated water there. St, Louis Mo. uses river water for their drink water that has been recycled about fifteen times. Communities upstream, filter and sanitize it for drinking water and then treat it, returning it to streams that run into the Missouri and Mississippi Rivers. Luckily, the MUD flocculates the BEASTIES (MUD and BEASTIES are scientific terms for the content of the Big Muddy, and people poop (microsoft assures me this is childish language)). So they filter out the muddy beasties and sterilize the water (with LOTS of choline).
Not only did the marine traffic establish the City, but the ports (Benicia (import cars) Martinez (petroleum in and out), Oakland (Containers) and SF (tourists) still are major contributors to our economy.
But, yes, SF is a continent away from CTS

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer))

I like your idea more better - much cheaper - no moving parts. It seems the state requires 50% of mountain runoff must go to the sea, 40% to farmers, and 10% to humans. So it makes great sense to hit the humans with the burden of saving enough water to save the state.
The Asian Carp love Big Muddy - I think we should give the bay smelt a chance to enjoy similar conditions and your idea fits SO well.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Reverse_Bias (Electrical)14 Aug 21 06:58 Got this from a twitter post. The article is behind a paywall so I just have the graphic. It shows a lot of overloaded columns in the section that collapsed. https://twitter.com/XinzhengLu/status/142612984022...)

Starting with the post referenced, I recall Column L-8 (I think) was reported to be loaded to 1.89 X or "axial compression load ratio".
So I had to check. This is rough and quick. I see L-8 has 23' X 22 ' is 506 sf trib ea floor, is 12X24 size, and has 12-#10 bars in the lower section. This is from the drawings posted previously and may not be the final conditions.
Using slab weight and 15 psf added dead load and 10 psf real live load, all unfactored, I see 861 Kips real DL and 70 Kips real Live Load, for a total of 931 Kips axial only below the Basement.
I have long forgotten the reduction factors for columns but 4 KSI x 12 x 24 =1152 Kips and 15 in^2x 40 KSI = 600 Kips for a total of 1752 Kips at 100% (no phi), Now if phi is 0.60 that gives a possible capacity in the order of 1051 Kips.
So we have something like 931 Kips real load in the lower section of the column and a reasonable capacity of 1051 Kips. Too close for comfort but likely stable if all components contribute as expected and loads used are representative of conditions at the time. BUT little room for moments and secondary stresses.
Takeaway - for this quick examination the column should have supported the load. And it did for 40 years.
The numbers and relationships and factors can be pushed in many directions, but I do not yet see a failure due to inadequate design of this column. A more exacting analysis may reveal otherwise.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
I seem to remember (BuildingIntegrity) that the 50 ton+/- planters aren't on the prints?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley)

Yes. Standing water level in permeable ground is close to but slightly higher than the level of a nearby body of water. Higher because of infiltrating rainwater (etc) moving seaward. A well is just a more efficient means of connecting a water source to that movement. In porous sand between two adjacent arms of the ocean the SWL will be within a few inches of sea level and will move with tides to some extent.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie)

San Francisco would do better to drill a tunnel from their Oceanside Water Pollution Control Plant to the bay and dump their fresh treated water there. St, Louis Mo. uses river water for their drink water that has been recycled about fifteen times.

A wise recommendation. The City of St. Louis (which is a separate entity from St. Louis County) does have excellent tap water, which is one of the reasons why we also have such good restaurants. This piece describes how we purify mostly Missouri River water, using lime and ferric sulfate to precipitate the sediments, and definitely return cleaner water to the Mississippi than what arrived in our intakes.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley (Structural)16 Aug 21 20:39 It seems the state requires 50% of mountain runoff must go to the sea, 40% to farmers, and 10% to humans. So it makes great sense to hit the humans with the burden of saving enough water to save the state. The Asian Carp love Big Muddy - I think we should give the bay smelt a chance to enjoy similar conditions and your idea fits SO well.)

Ok I am trying to understand the California Political Force, by exploring the mandated California Water Allocations. We read in the news that California does not have enough fresh water, and looking at the dropping levels of Lake Mead, we know where California is getting a lot of water from a shrinking resource.

We also know Sea Levels are rising, so why on earth would California require that 50% of Mountain Fresh Water Runoff be dumped/wasted in the ocean rather than using that fresh water to meet California human needs, and farmers needs, etc???

Why waste that fresh water source when fresh water is scare in California?

It reminds me of California also allowing brush to grow up around power lines, and then enjoy the brown outs....

Edit: I don't think it is possible to save California from their Political Agenda's....

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
Easier that saving the citizens of FL and TX from theirs?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
Maybe we can reverse the California Aqueduct and ship fresh treated water from LA (the one near San Diego) back north to the farmers. Humm... How can I make water flow uphill?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

SFCharlie, excellent Point!

Edit: What about injection wells so water can flow laterally via underground aquifer?

Edit2: I know put Engineers in charge of everything!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Why not a series of Harbor Freight water pumps running full tilt, increasing emissions output to the point of sea level rise to push the water uphill for us? If we're going to e-vehicles soon, we need to burn all that gasoline somehow.

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

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (All About Money (Aerospace)16 Aug 21 22:33)

Edit2: I know put Engineers in charge of everything!
Now, who with the authority to do so, would consider it for more that 7 microseconds?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

*spins in circles until he pukes*

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Demented (Industrial))

So is the message here, Dan is a slow learner? Or is the message here, it does not matter how many times the rebar placement is disapproved by the inspector, it only takes one EOR 'Trump' Card to override all disapprovals in Florida?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

According to Wikipedia, California is dumping a trillion gallons of fresh Water in the ocean to protect the Delta Smelt, a three inch bait fish.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I don't know much of nuthin', but if thats a 3 inch fish, I have some tiny ass hands.

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

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Apparently 2-3 size is correct, but obviously the one pictured don't fit that model.

From Wikipedia, "The delta smelt (Hypomesus transpacificus) is an endangered[1][2] slender-bodied smelt, about 5 to 7 cm (2.0 to 2.8 in) long, in the family Osmeridae. Endemic to the upper Sacramento-San Joaquin Estuary of California, it mainly inhabits the freshwater-saltwater mixing zone of the estuary, except during its spawning season, when it migrates upstream to fresh water following winter "first flush" flow events (around March to May).[3] It functions as an indicator species for the overall health of the Delta's ecosystem.[4]

Because of its one-year lifecycle and relatively low fecundity, it is very susceptible to changes in the environmental conditions of its native habitat.[5] Efforts to protect the endangered fish from further decline have focused on limiting or modifying the large-scale pumping activities of state and federal water projects at the southern end of the estuary, thereby limiting water available to farming. However, these efforts have not prevented the species from becoming functionally extinct in the wild.[6]"

Edit: I guess the root problem is humans wanting to live in naturally inhabitable areas, like in high rise condo's on reclaimed Ocean, or in the desert and have their green grass too. All at a steep price to bring in all the things necessary to support human occupation.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Pretty views are pretty views.

Have there been any updates on the checking of the slab and piles, or if that emergency work to brace the tub has been done yet? I'm kinda of assuming they're waiting to get in and inspect everything until the walls and pool are braced. Safety first with the white hats. Safety third, yellow.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer)(OP)16 Aug 21 22:25 Maybe we can reverse the California Aqueduct and ship fresh treated water from LA (the one near San Diego) back north to the farmers. Humm... How can I make water flow uphill?)

Don't need to - we can haul the water with the Bullet Train - nobody's going to ride it anyway. Just gotta get the water to Corcoran at the south end of the line and like a flash it will be in Chowchilla at the north end.
That is the extent of the rails. Why those two metropolis centers? Corcoran is the Men's Prison and Chowchilla is the Women's prison. California appreciates it's felons.
What's that you say? No Bullet TRAIN to use on the new railway that is built and cost billions? That's OK -just use an old SP yard engine and tank cars. The rails are standard gauge. Can't make the speed needed to match the superelevation? Just put bigger trucks on the down side. Why does everybody make this difficult?
I know - off topic. Sorry - but it IS a disaster.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Castaic can make water move uphill.

Fish are an indication of many things and are probably more important than a bunch more people in a place that already has too many.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (davidbeach (Electrical)17 Aug 21 02:44)

Castaic can make water move uphill.
...is it pumped storage?, or how should I interpret this?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Edit: I guess the root problem is humans
Full stop.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Castaic is pumped storage. In the late '70's the density of what they were pumping and drawing down was well above 1. Algae sludge much more than water. No, it can't actually get to to point of south-to-north flows but it overcomes most of the elevation problems.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (davidbeach (Electrical)17 Aug 21 04:52)

Castaic is pumped storage.
Cool Thanks for the info. ...wonder why it's not highlighted on their web page?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

6
Polite request, can we please stay on topic.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

2
During the FIU bridge collapse discussions you would often tell a poster to reread the thread from the beginning cause this subject had already been mentioned. I would never wish nor ask that of anyone for this thread. After returning from vacation I came back and read from Jul 4 to about Jul 31 straight thru and my brain nearly exploded. I dare anyone to go back and read this from the beginning.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (RandomTaskkk (Structural)17 Aug 21 08:22)

Polite request, can we please stay on topic
yes Thank you!

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

@TheGreenLama thank you for the laugh

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (By WPTV - Staff Published: Aug. 17, 2021 at 9:22 AM PDT|Updated: 10 hours ago)

Building safety organizations from around the country gathered Tuesday in West Palm Beach for a dialogue on how to prevent another Surfside condo collapse.
Building safety groups meet following Surfside condo collapse

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (MaudSTL (Computer)18 Aug 21 04:12)

this is a well written human interest story
I really enjoyed this, Thank you.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer)(OP)18 Aug 21 02:36)

It would seem to be an exercise in futility to manage a structure constructed in an era of corruption at multiple levels. You would have no confidence in the substance of what you're overseeing.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

From the building safety forum article:
"[The Surfside building] almost looked like a planned implosion, in the manner that the building collapsed. So, obviously, there was a lot of speculations initially," Ascunce said.

He means well but I don't believe anyone aiming for credibility in public should say stuff like that. There is idiot speculation and hot air on Reddit & YouTube in these terms and the merest mention just feeds it.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (AusG (Petroleum)18 Aug 21 07:30)

From the building safety forum article:
I was left wishing I knew what was actually said at the meeting.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

So, here is a unique parking garage. It's South Lawn in Melbourne. And each column is shaped like this to support a tree above it. The tree's are perfectly positioned above each column and there is a lawn above the garage. It's very unique and I felt that it was a good example given other examples. It's constructed 10 years before CTS. It's old but still in good condition.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

AutisticBez - that looks like the building a structural engineer designed after reading an article on shear punch failure of column slab connections.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (AusG (Petroleum) 18 Aug 21 07:30 [The Surfside building)

almost looked like a planned implosion, in the manner that the building collapsed.]...
He means well but I don't believe anyone aiming for credibility in public should say stuff like that.

Actually, I agree with how it looks. "Planned implosions" seek to weaken the structural elements at the ground level of a structure, which indicates to me that CTS collapsed because of the failure of ground level structural elements and probably not as a result of falling objects.

The video of the demolition of the part of the structure that remained standing is strikingly similar to the fuzzy security video of the initial collapse. If one were to use the planned demolition as a model of the initial collapse, I think one would have to prove that the initial collapse was NOT due to failure of ground level structural elements.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Hey, this is Jinal and I am new to this forum. But I am pretty sure everyone has seen Building Integrity's video on engineering failures. I have have few comments on it along with a part of incorrect information they may be sending to the user.
1. When he talks about high reinforcement of column, he mentions something about plastic yielding and all. Which doesn't make sense, because axial plastic yielding does not occur in columns even when they have high reinforcement ratio. The plastic yielding mainly occurs because of seismic loads. Rest of all the conditions, like wind and the daily gravity loads, the columns and all the building elements are essentially elastic. That too at ultimate loads.

2. When he talks about the pool deck and its capacity against the dead loads itself. He is not presenting any calculations. While when you do the calculations then the reinforcement works for just the 9.5" pool deck. But it does not work when we consider all the toping of sand, pavers and everything on top of it. So that is also an incorrect statement.

3. The temperature and shrinkage reinforcement splice. Again he is incorrect over here, and the splice and temperature and shrinkage reinforcement was correctly provided and detailed.

I do feel that he is mainly involved in concrete repairs through his career and would have limited understand on how buildings are actually designed, detailed and the actual capacities of members, in terms of reliability analysis. That is how the code equations derive the capacity with conservative equations while the actual capacities are much higher. He must be great at concrete repair and reinforcement repairs.

I am not being toxic here, but I just want everyone to understand the underlying assumptions that he is considering while presenting and a part, primarily related to load and resistance are little incorrect.

I did create a video 2 weeks prior to BI's video that flows along the same lines and talks about pool deck deficiencies but also go a bit deeper into actual analysis and repercussions of under designing a slab with some calculations. I think structural engineers may be interested in this so just thought of sharing.

https://youtu.be/fFQ7ey5CDLc

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (StructuralMadness (Structural)18 Aug 21 16:49)

Hey, this is Jinal and I am new to this forum.
...about 2. BuildingIntegrity is talking about the building as design before the sand and tiles were added. He also notes that the 50 ton+/- planters aren't on the prints.
...about 3. "...reinforcement was correctly provided and detailed."
I think someone pointed out that the specified rebar didn't fit in the specified column and still meet code.
There are two obvious solutions:
The structural engineer could have specified a wider column. OR
The construction crew could have left out some of the rebar.
Unfortunately, the debris seems to says the later happened.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Hi Charlie, so about point 2 again, he does mention in his video that the reinforcement was just barely enough to handle the slab's own weight, when someone mentions (in structural engineering community especially) just about the self weight of the member, we consider the member weight only. So, if I perform the calculations for the slab, then the steel that was provided was enough to handle its own weight plus the weight of pavers and sand and all except the planter boxes. Now the "direct design method" also has some inherent conservatism on how we calculate reinforcement as well as the way the slab typically engages the reinforcement in two directions. If we eliminate this conservatism, then the slab was just barely overstressed because of pavers and added sand and topping, note that I haven't included the weight of people on pool deck. This overstress isn't an issue in its own, the direct effects of this overstress is an issue. And what this overstress does is, it typically adds more demands to slab column connection. Again from engineering standpoint his concepts; the way he presented was incorrect. Based on building code equations if an element fails, then it is not the true failure of the element. Realistically the failure capacity is about 1.3 times higher than that plus there is inherent material over strength. Now for nonstructural engineers, it sounds like when someone mentions it fails, it should collapse immediately. But no that is not correct.

Coming on t point 3: The temperature and shrinkage reinforcement splice, where he shows the details call out for 6" overlap vs what should have been as 20" overlap is incorrect. Because the 6" overlap does meet the intent of the building code per ACI 318-77. The idea is, at the support, we add steel near the top face of the slab which is suppose to provide temperature and shrinkage crack resistance. Even in the current code the detail is still the same, except the requirement of integrity reinforcement. This integrity reinforcement prevents complete collapse of slab once punching failure has occurred and this requirement was added into the building code after Ronan point collapse in 1980s.

I mean the way videos are made on Youtube by a lot of non structural engineers. When I analyze the building, it was designed okay for the most part (95% of it). It was incorrectly designed for may be 5% of it. It is common that condos will have different finishes, heavier loading, added palm trees and planter boxes. There is inherent factor of safety that is considered from strength perspective and factored up loads from design load perspective so that people don't have to retrofit their home / apartment just to add marble on the floor. But again a lot of people miss it and people who don't actually design buildings miss it.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
From my perspective, BuildingIntegrity's point about the beams being removed when the valet parking was dropped to the level of the pool deck, was very telling.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Also, I think they structural engineer could have provided bigger column instead of 16x16 columns, but I doubt if the structural engineer even imagined anything like this remotely happening. The high % of reinforcement in the splice region that BI is talking about is definitely a "small" concern. I mean overall the column had reinforcement % of 9.2% compared to 8% limit specified by building code in 30" length of the column above pool deck. But I don't think that would have played a major role in the collapse. It is just another thing that structural engineer kind of waved his hands and thought that it is probably okay. Also based on the time of collapse, the building was no where near to it's full load carrying capacity. Far from it I would say, so the collapse should have been because of some instability of the column / step beam joint or deck pulling the column away (which again is a bit unlikely). Also, the consolidation of concrete is an issue with high rebar %, but still, based on the construction requirements of east coast which is a non seismic region, the overall congestion of steel there will be significantly less than the west coast and I have seen significantly high % of reinforcement in the columns without any consolidation issue. May be because of modern construction and concrete technology.

Also the contractor cannot reduce the rebar, because it is also essential in carrying the load of the building. Even if concrete column is in compression and concrete is good in compression, the column capacity comes from a combination of steel + concrete as both the elements compress together and support the building above. So contractor didn't have any choice.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

On the point of pool deck last minute changes, here is something interesting. Even if that change wouldn't have been made, just 15' next to those beams that were removed, the deck was still under designed. So regardless of the change, the design of pool deck in general had some issues and would have required maintenance no matter what. But yes, that was a design change later on. And I think it was just important to check the pool deck after the design change. That is what forensic structural engineers do. They analyze the as built conditions and latest set of drawings. Because that is all matters.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (StructuralMadness (Structural)18 Aug 21 21:39)

Also the contractor cannot reduce the rebar,
The debris says the rebar was reduced

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (StructuralMadness (Structural) 18 Aug 21 16:49 Hey, this is Jinal and I am new to this forum. But I am pretty sure everyone has seen Building Integrity's video on engineering failures.)

Hey Jinal, Jason, of Building Integrity is not a member here and has no way of defending his analysis of the collapse on this forum. This is the second site I have seen you questioning his findings and conclusions. I think a better method would be for you to contact him through his Youtube account and discuss your concerns with him directly. Following him around the web and bad mouthing him behind his back just seems rather sleazy.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Hey Nukeman, hi! I did try reaching him out couple of times and couldn't do it successfully. I am not sure if I have questioned his findings anywhere else. Also, I am not bad mouthing him, so far what he had done was a really good job at explaining people. And again his latest video does have some credibility to it, and again I apologize to all of you if you feel I am coming out as negative. What I am implying is, to a nonstructural engineer it may seem like a lot of issues were present during construction, design and maintenance, but in reality the answer to this is rather very mundane and boring. Like Imagine NIST coming out and saying hey it was really just that pool deck collapse was because of some design issue and building collapse was unfortunate and coincidental, then this would lead to a lot of people blaming NIST for not doing their job appropriately. Just like what happened with WTC collapses. And again I am just drawing lines on things that actually wouldn't either contribute to building failure or are not as extreme as they are being represented.

I was also hoping some structural engineers will engage in this discussion and see if we do end up arriving at the same conclusion.

EDIT: Also I do agree with the conclusion that he has provided for the building failure in terms of slab being under designed. I have run the analysis both "Direct design method" as well as Finite element analysis and I did come up to the same conclusion that the pool deck was under reinforced and that started the collapse chain. So I am not even question his conclusion. But being a structural engineer, I was surprised that he added few incorrect information / details which were to an extent irrelevant. That is the reason I joined the forum to see what other structural engineers think about this.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I am not sure if I have questioned his findings anywhere else.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Hey Nukeman, thanks for sending that link over, and yes I have joined that close group, interesting that we met here again. I have not discredited his findings, what I am trying to explain to everyone in that group is not to panic and question everything about buildings they are living in. Regarding planter boxes as well, like if you would ask any structural engineer you would get a similar response. I think what Josh did not influence enough is the level of concern these changes / adds contribute to the overall collapse. Nowhere will you see me calling him our as full of BS. Mainly because I have agreed with a lot of his conclusions. The things that I have not agreed upon which I do have a right to, if either the seriousness of the issue or the extrapolation of the design / details / changes towards the collapse. Because again, a lot of people freak out. While again that is not the case. Just because this building collapsed doesn't mean that you have to question all the buildings around you. I mean that is why I joined the group, is mainly to answer your questions so you guys can understand what a structural engineer would actually think.

Again, you will see videos created by very few engineers (including me) who are probably just not as versatile and experienced enough and who draws the conclusions very early on. Why do we think a lot of renowned researchers, forensic experts and structural engineers haven't said anything? Because they don't want to scare the public. Like adding marble to your floor does not lead to building collapse. That is all I am trying to do here.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
This is a tragedy, at least 98 people lost their lives. 100% lost the whole value of their structure. Many their life saving.

#### Quote (StructuralMadness (Structural)18 Aug 21 21:18)

When I analyze the building, it was designed okay for the most part (95% of it). It was incorrectly designed for may be 5% of it.
To me, the lesson here is that the structural design has to be 100%. What scares me is you don't want to scare people but you say things like "it was designed okay for the most part (95% of it)"

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Ok, let’s talk from a structural point of view, about why in some condo units, did owners install thick set tile/marble floors, and not thin set, but not in all units? If the structural slab is reasonably level and flat in the condo, the cheapest and easiest solution is thin set tile laid directly on slab.

When I see thick set used on concrete slab floors, in some condo’s, but not all, it tells me the floor is out of level or has so much mid span deflection, that folks are willing to pay additional cost for thick set to re-level the floor.

This tells me we have a slab deflection issue or uneven changes in column elevations. So what has changed structurally with time to cause either one of these conditions. Either one it would seem would add stress and strain on structural members in the affected areas of building?

Raising floor height with thick set affects built in kitchen cabinets and all doors and base molding for example. Not a trivial go from vinyl or carpet flooring replacement.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote:

BTW how do you guys quote someone else's response?

Cut and paste the content that you wish to quote. Cntrl "C"
Click the cartoon speech icon.
You will see:

You may enter the source of the quote or leave this blank.
Click OK or Hit "Enter"

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I tried to recalculate the weight of the planters full of water as well as the walls. This time I tried to estimate the height of the planters a little better. I came up with an estimate of 42 in for the big square ones and 24 in for the lower and longer ones. I also missed some. In this calculation I am including ALL the planters, whereas before I had only included the weight of the planters in the collapsed section (although I missed some).

As before, I used the measurement feature in Acrobat. One can scale the pdf to the drawing. Unfortunately, the scaling does not seem to get saved with the file. It appears to be a per session feature. I used a drawing that had been submitted as part of the minutes of the Board of Directors of the CTS condo association on Oct 14, 2020. It is an 83 page document that was posted here, but I did not save the url. My apologies. The drawing I used was on page 43.

I extracted it and was able to remove the photos that had obscured what appear to be the drawings of the planters as of that date. The drawing was done by Morabito Consultants, bears a date of July 13, 2020, is titled First Floor (Lobby Level) Framing Plan and is identified as Sheet S2A-1.1. I have identified the planters with as #1, #2, etc. in blue. I scaled the drawing based on the 6 foot dimension for planter no. 1 (I hope this was a planter!), based on a dimension marked on some other blueprint. Building Integrity mentioned that he could not find a drawing of the planters, so I thought I would try to contribute this drawing to the mystery.

The dimensions of the planters are in red with the dimension itself in black. The scaling I used in the Acrobat session to make the dimension notations was 1 in to 13.73 ft. The original size of the drawing is 36 in by 24 in. I am (hopefully) attaching the cleaned up and annotated copy herewith with full resolution. I am also going to try to embed a lower resolution version.

I am also attaching and embedding (with luck) a pdf of my calculations so that somebody can check them. The planters appear to be much heavier than I previously thought. Based on Morabito's blueprint, the walls of the planters appear to be about 10 inches thick. That may or may not be accurate. I assumed the walls were constructed with CMUs. Maybe they weren't or maybe they were thinner, but this is a start anyway.

The total calculated weight of the planters completely empty is about 147 metric tons or almost 325,000 lbs. It was reported that it had been raining heavily. If the planters were full of water, then the weight would have increased by another 180 metric tons or close to 400,000 lbs for a total weight full of water calculated at close to 330 metric tons or over 700,000 lbs! Did I make a mistake somewhere? It's late and that may be. Hopefully somebody can point it out to me.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

The 4x8 planters as they were called were modified to 1.143m high around the same time the weep holes were plugged.
*shrugs*
Just more gravity.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

A House of Cards: The Miami Condo Collapse Exposes a Dehumanized Mindset in the Built Environment

Also brings up Grenfell Tower and other examples both large and small; good read for anyone in the AEC industry.

"While it may be tempting to dismiss these incidents as “cherry-picking” from an otherwise safe and pure building stock, the process of designing and constructing our built environment is fueled by an accepted norm of pushing health and safety regulations to their practical limits. Such fears were recently underlined in a major survey of construction professionals by the British Board of Agrément (BBA), a major UK body for issuing certificates for construction products. The survey asked respondents what factors they believed were “the most likely to cause an emerging or actual disaster in the next few years.” The top two results, ranking far higher than any other risks, were “poor workmanship / installation quality” and “uncontrolled value engineering.” The message from the industry is clear: our preoccupation with delivering projects for the cheapest price, with the fewest resources possible, is the single most likely factor to cause a future building disaster."

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

@IEGeezer - I need to look more closely at your plan and calcs, but I'm assuming you're going with a maximum possible water weight for the planters by volume? They appeared to be fairly filled-out with dirt and vegetation, and most likely pretty saturated with water. I'm curious whether planters full of dirt, dense shrubs, and water would actually weigh more than the volume of water alone?

I remember the discussion on the core samples and slab composition, but without going through the 10 previous threads, I don't recall if there was an idea of just how much water the slab components may have been holding?

It's going to be interesting to see what the verdict is down the line as far as just how overstressed the pool deck ended up. Original weight of materials plus additional layer of sand and pavers, planters full of vegetation, undernourished slab, lack of/failed waterproofing / trapped water, the occasional likely overweight vehicular intrusion, improper repairs (still wondering where that mystery partial slab replacement was)...am I missing anything?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (arbitraria (Civil/Environmental)

And don’t forget weight of large palm trees until 2017 and their root damage

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

article in new Pile Buck on p. 128 discussing repair procedures for similar bldgs. A nearby hi rise's concrete tested 1100 PSI!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Regarding the planters… I’m a bit surprised by some of the musings.

Water alone is about 60 lb/ft3
Saturated soil 115-130 lb/ft3

I think they often use lightweight closed cell geofoams in the bottoms of planters to elevate the vegetation without adding weight.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Spartan5 (Civil/Environmental)19 Aug 21 15:52 Regarding the planters… I’m a bit surprised by some of the musings.)

I agree. It is not like water will add another 64.4 lb/ft3. A soil saturated with water just has air pockets filled with water and this depends on the void ratio of the soil. Good clarification there.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer)(OP)19 Aug 21 04:21 This is a tragedy, at least 98 people lost their lives. 100% lost the whole value of their structure. Many their life saving.)

Charlie,
I completely agree, every structure is supposed to exceed the building code requirements, not just meet the requirements. But a lot of engineers have their hands tied because some developers / architects push the engineers to either reduce the member size or reinforcement tonnage. Again there are only a few. Fortunately through my career I have had a pleasure to work with good architects and developers and since I am mainly involved with designing buildings on west coast where seismic design governs a lot of things in the structure.

As a side note a lot of times there are owner driven / architect driven changes towards the end of the project and they are reluctant to shift the deadline. Now for them it may be just moving a column or eliminating a step, but for engineers it is redefining load path. Sometimes it is not a big deal, but a lot of times we face time crunch even after working 70 hour weeks to accommodate that change. And that's where a lot of mistake could happen. I think what arbitraria shared is a great post and talks a lot about reality that structural engineers face on day to day basis. It is not bad to push boundaries, but then at what cost? Because once the robustness and redundancy of the structural system is reduced, a system mainly just relies on a single load path which is a big issue. It is having just one road connecting your home to city center and if it breaks you can't travel kind of scenario.

Again, structural engineer's work is really important but it is always been shadowed by a lot of factors and that's where not everyone pays attention / listens to them. I think all the the structural engineers around the world feel the same way.

EDITS: "But a lot of engineers have their hands tied because some developers / architects push the engineers to either reduce the member size or reinforcement tonnage." A bit of explanation so that someone don't misunderstand the statement. What I meant by pushing to the limit is still satisfying the building code requirements, but then there is no more room for error from construction to material strength or any accidental event. A good example for Champlain towers condo collapse could be those skinny 16x16 columns that were heavily reinforced or the pool deck with marginal reinforcement in most of the region (Excluding that part that was under designed).

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Phil1934 (Geotechnical)19 Aug 21 15:26 A nearby hi rise's concrete tested 1100 PSI!)

If that was structural concrete it is WAY past time to vacate.
Could this be an extreme case of chloride damage to concrete? Did they test for that?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (StructuralMadness) every structure is supposed to exceed the building code requirements, not just meet the requirements.But a lot of engineers have their hands tied because some developers / architects push the engineers to either reduce the member size or reinforcement tonnage)

Wow, this statement could really be seen in the wrong light. Yes, developers/architects push the limits to achieve their own agendas but I would seriously doubt that any engineer would knowingly ignore code requirements and compromise structural safety and serviceability to satisfy them. They would surely scoff at the suggestion that they have such powers.

Back to engineering:
Jinal, I'm curious to hear your thoughts on the wall noises that unit 111 heard in the lead up to the collapse. Yes, load re-distribution, but why exactly, what's happening in the structure, the planter area has evidently not yet collapsed. I am not a protagonist of top-down collapse btw, I don't have an agenda here.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Back to engineering: Jinal, I'm curious to hear your thoughts on the wall noises that unit 111 heard in the lead up to the collapse.)

I have thought about it for quite some time. Like why the creaking noises and why on the wall. Because the walls are just partition walls and these could very well be just dry walls since the building was built in 1980. I am not sure of cold formed steel existed back then. Again I have not grown up in US so can't say for sure. So when someone says low noises, could it be they were just trying to describe the type of noise, "Like someone banging on the wall" but it could have been a series of concrete failures? Like the deck failure itself could have progressed first from a single concentrated region through to the entire deck collapse prior to the building failure.

Like the failure of the pool deck should have started at one column point. And apartment 111 was the closest apartment to any failure points. And remember that it was just not her, but the security guard also head some series of loud noises. Which means it was not the wall banging for sure, the statement was just a metaphor. Even though there were multiple slab column joints that showed punching failures when doing the actual calculations, not that because of inherent material over-strength and factors of safety the actual capacity would be much higher. And the magnitude of rust, rebar delamination as well as cracks would have varied all across the deck. Also, as concrete breaks along a failure plane, it does typically create loud noise. Like we can hear it in structural test labs whenever they perform these tests. You can even hear such noises in steel buildings when bolt slip occurs. So once one of the section fails, it will again redistribute loads and other sections will see the stress and that's how it should ideally progress. This is what we know as series of brittle failures that are responsible for the deck collapse. I think when they head the loud bang, that's when the entire deck actually collapsed.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Spartan5)

I think they often use lightweight closed cell geofoams in the bottoms of planters to elevate the vegetation without adding weight.

This is what I was getting at, and articulated very poorly, my apologies. Taking @IEGeezer's calculations for water volume, and comparing that weight to potential planter configurations (very heavy if the whole thing is full of dirt and plants, not so much if there's an internal platform to optimize space and weight, and how those would compare to his numbers).

Thanks for the numbers @Spartan5, I never did much in the way of "fun" landscape design, most of the projects I worked on in site civil were institutional and as such the landscaping components were mostly related to erosion control. I should really go back and look at the related details from the original plans. The Morabito details seemed to imply the new planters would be full-depth soil but I didn't really look very hard so I'm probably mistaken.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Demented (Industrial) 19 Aug 21 09:57 The 4x8 planters as they were called were modified to 1.143m high around the same time the weep holes were plugged. *shrugs* Just more gravity. )

That would be about 45 inches tall. Where did you get that the big planters were 4 ft by 8 ft. In this picture, they look roughly square as they do in the Morabito Consultants drawing I referenced.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Quote (Back to engineering: I have thought about it for quite some time. Like why the creaking noises and why on the wall. Because the walls are just partition walls and these could very well be just dry walls since the building was built in 1980.)

The walls were cement masonry units so could inadvertently end up carrying vertical load. Just throwing some ideas out there but think about slab deflections, gaps between top of wall and slab (if any), vertical lengths of wall from level 1 to roof on façade, vertical load transfer accumulating downward onto the stiffer beam element on pool deck level gridline 10 between column grids K/L and L/M.

Could the beam on gridline 10, at grid L (only 16.5" deep), have started to drop a little from shear failure initiation, loads then distributed to other columns and walls (creaking).....

Did the engineer intend the beam on grid 10 between K & M to be 27.5" and not 16.5"? So many possibilities and permutations.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Spartan5 (Civil/Environmental) 19 Aug 21 15:52 Regarding the planters… I’m a bit surprised by some of the musings. Water alone is about 60 lb/ft3 Dry soil about 100-115 lb/ft3 Saturated soil 115-130 lb/ft3)

To make it easier to compare to my calculations:

60 lb/ft3 is about 0.96 kg/L
64.4 lb/ft3 is about 1.03 kg/L
100 lb/ft3 is about 1.60 kg/L
115 lb/ft3 is about 1.84 kg/L and
130 lb/ft3 is about 2.08 kg/L

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (W-streng)

Jinal, I'm curious to hear your thoughts on the wall noises that unit 111 heard

Jinal, please review the data tab in the Timeline spreadsheet for a detailed compilation of collapse witness statements made in publicly available interviews.

Chani Nir heard knocking sounds when she got home at 11 PM. These continued until the first collapse. Her mother Sarah noticed the knocking sounds not long after she got home at 12:30, and has stated that they sounded like hanging pictures on the wall or construction going on in the apartment upstairs. These sounds gained in intensity over time. We do not know if Security Guard Shamoka Furman also heard the knocking sounds in the lobby. We also do not know what time these sounds actually started, if in fact they started before 11 PM.

The first collapse was at 1:10. All three Nirs perceived it as a wall collapsing from above, as if someone were doing demolition work in the middle of the night. Shamoka Furman also heard this loud sound in the lobby, and perceived it as something to do with the elevator. But since the elevator threw no alarms, she wasn’t concerned that anything was wrong.

The second collapse at ~1:15 was the deck, and the third collapse at ~1:22 was the building.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
----Sorry Maud---- I wrote this while you were posting. Your right.
I have been thinking, (dangerous, I know.) that since to pool deck, itself, remained remarkably intact, with the columns punching through one at a time. That would result in a series of banging...

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie)

Sorry Maud

Not to worry. I am just trying to make sure we are all on the same page where these warning signs are concerned. I have always thought the knocking was rebar popping, but I am not qualified to have an opinion.

The tricky part of the first collapse at 1:10 is that if it occurred in the garage, the Vazquezes either couldn’t or didn’t see it as they parked, walked to the elevator, and boarded it to go up to the lobby. As you know, they were in the elevator when the deck collapsed. And all their statement says is that they heard loud cracking sounds a few seconds before getting on the elevator.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (MaudSTL (Computer)19 Aug 21 20:49 Quote (SFCharlie) Sorry Maud I have always thought the knocking was rebar popping, but I am not qualified to have an opinion.)

We all speculating of course but for interest sake, my thoughts have been that the sounds are of the masonry units taking up compressive stresses/strains as the vertical load on then slowly increases until they finally fail in crushing and/or buckling and then 'crash' onto the floor slab above the Nirs.

The fact that this precedes the collapse is what intrigues me most.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (W-streng)

The fact that this precedes the collapse is what intrigues me most.

More than one engineer has commented that the building was issuing warnings that no one understood.

Your theory is the first I’ve heard that implies that the first collapse actually could have come from above. Most folks have been been thinking part of a slab collapsed in the garage. If part of a partition on the second floor actually did collapse, I would imagine that could have contributed to a column buckling, right?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (MaudSTL (Computer)19 Aug 21 21:26 Quote (W-streng) More than one engineer has commented that the building was issuing warnings that no one understood. Your theory is the first I’ve heard that implies that the first collapse actually could have come from above. Most folks have been been thinking part of a slab collapsed in the garage. If part of a partition on the second floor actually did collapse, I would imagine that could have contributed to a column buckling, right?)

The video evidence points to the first actual structural failure/collapse being the pool deck area, no disputing that from my side.
I don't have a theory, far too many unknowns, I'm just trying to figure out how the pool deck collapse was preceded by creaking in the walls above the Nirs. It's easy to say that load was being re-distributed but WHY. The high-rise portion hadn't lost any structure at 11pm the night before.

Your Q: The partition wall collapse would very unlikely buckle a column. It shouldn't be taking any load and collapsing anyway, something would already have gone very wrong for it to be taking load.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

The sounds of structural distress, wherever it is, will be transmitted through all of the interconnected pieces of the building. The floors, having the most coverings (flooring, furniture, clothes, rugs, etc. will appear effectively transmit less sound than the walls and ceiling (which has the least amount of coverings on it). Hence, “noises from above.”

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I had two points about over reliance on the direction of noise in the forensic analysis, but since Spartan covered the first I only have one.

The physical evidence suggests a ground level failure originating at the garage. If a ground level column failed at the exterior face of the building, which appears to be the case, the remaining column directly above the failure ceases to carry the structure load and begins transferring load to all adacent, remaining columns. This progression overstresses those remaining columns at all levels, which would explain noise and failure at every floor of the building. It is entirely possible for a garage level failure, to ultimately result in a collapse that begins at one of the upper levels.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I recalculated the weight of the planters based on the suggestions given herein. Geofoam was specified on Sheet A2C-1.0 (Level 1 Floor Plan) (pg 4) from 8777-collins-avenue---preliminary-review-plans-for-40-year-re-certification.pdf available at https://www.townofsurfsidefl.gov/departments-servi....

It is unknown if geofoam had actually been installed in the planters, but I assumed for the puirpose of these calculations that it was. On drawing LP-1 (pg 73 from the same source) (the lanscaping plan) the specified soil was to be installed to 18 inch depth, but 36 inches surrounding tree root balls. There is a disconnect because on Sheet A2C-1.0, the engineer specifies 1 to 6 inches and no more than 80 lb/f3. Waterlogged soil can weigh up to 130 lb/ft3 regardless of what the engineer wants. Therefore, I assumed 18 inches of waterlogged soil for the short planters and 36 inches for the tall planters.

On Sheet S2C-2.5 (pg 19 from the same source and titled Plaza Details) the planter walls are specified as 8 inch CMU wall with reinforcement, so I changed the width from 10 inches to 8. In addition, I used page 11 from the same source, titled Level 1 Slab Reinforcement and Framing Plan, for remeasuring the planter dimensions using the scaling and measurement features of Acrobat. I set the scale to the one shown on the plan and there was almost perfect agreement when I measured a labeled dimension. Accordingly, I changed all the size of the planters to the new measurements and I noticed that I had missed some. I am attaching and embeding the new plan with the measurements as well as a pdf of the calculations. Maybe this might shed some light on the collapse.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (CE3627)

…noise and failure at every floor of the building.

From 11 PM through 1:10 AM, we have reports of increasingly intense knocking noises heard on the first floor, and at 1:10 we have reports of a loud crash heard on the first floor, resulting in dust particles in 111. Other than the five people who were extracted from the rubble, the only other survivor in the part of the building that collapsed, Ileana Monteagudo up in 611, was asleep until around 1:15.

I’m trying to understand whether we can dismiss any direction of the sound origins as a possibility, and also whether there is a certain direction that is logically more probable based on what we believe are the origins of the building collapse.

So please check my understanding. Is it correct to say that both the sounds—knocking and crash—could have originated on any floor, even though we agree that the building collapse itself was caused by a ground level failure?

If that is correct, then can we say that the directionality perceived by the survivors may or may not be accurate…that the sounds could have come above, below, or off to one side or another?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

2
Based on the measurement of the weight of the planters I think that the probable point where punching shear first developed was column K13.1, followed by K12.1 as shown on the attached Sheet titled Level 1 Demo Plan and identified as Sheet D2C-1.0 from the Morabito bid documents referenced in my prior post.

Previously I9.1, K9.1 and L9.1 (as identified on the attached pdf; the numbering may vary on other drawings) had been identified as probably being the first columns to develop punching shear. However, based on the principle that a chain breaks at its weakest link, I would like to suggest that punching shear most likely developed at columns K13.1 and K12.1 before it developed at I, K and L9.1. Columns K13.1 and K12.1 are 12 in by 16 in type N columns, whereas I, K and L9.1 are type C columns which are 16 in by 16 in. It would stand to reason that the skinnier columns failed first. Column K13.1 is almost directly behind the elevators when one is in the vicinity of the office. Was that the loud sound that the security guard heard from the direction of the elevators? Maybe. Just food for thought. I have also labeled the weights of each planter shown on the drawing based on my previous post showing the recalculated weights for illustrative purposes. There are about 24.8 calculated metric tons of weight from the planters in the vicinity of columns K13.1 and K12.1. The video from Building Integrity influenced these thoughts.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

RE: Sounds

There is a difference between the planned demolition of the part of the building that remained standing and the part that fell. The columns of the part that was demolished suffered compression failure (due to explosives). What is striking about the debris field is the number of columns from the collapsed portion that still look relatively intact. Consequently, the columns from the collapsed part did NOT suffer compression failure. They failed by buckling.

When the punching shear developed, the columns in the center portion tried to buckle, but the building was still braced by the north and south sides. The swaying (or attempted swaying) movement must have caused very large stresses throughout the building and would likely explain noises from above and possible structural failures in the upper portions of the building before the collapse. Just a thought.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

4
RE: Sounds

I do not have any numbers to back this up. But just trying to visualise things I would expect that as soon as the lower (say ground floor) portion of the column is experiencing any distress (lets go with it's beginning to buckle because the pool slab has punching sheared off from the column and doubled the columns unrestrained length) the column loses some/most of it's load bearing capacity.

Most/all of the loads once carried in that column are now trying to find any alternative load path and redistribute to parts of the building which can carry them.

Since the column has failed at the bottom, but was supporting every level of the building; these alternative load paths could be for instance all floor slabs dropping into catenary action between the remaining exterior columns and cracking along the bottom face; or all slabs attempting to cantilever from the interior columns putting hogging moments (and cracking) over the top of the slabs at interior columns; or all slab to failed exterior column joints trying to hold together as a Vierendeel truss and taking up moments they are not designed for. Evidently things got so bad none of the possible alternative load paths, even acting in whatever combinations were possible, had enough capacity to hold the load being redistributed from the failed column.

In reality the building will have tried to hold the buckled/failed column loads any way it possibly could, so there will be a whole heap of these possible alternative load paths all in play at once. Maybe the CMU walls even tried to take some load (explaining the finger wide cracks in 611[?]) during the later stages of the attempt to redistribute the loads.

Obviously the load will take stiffest (stronger) paths first, progressively moving into less stiff (weaker) load paths until either the load is finally redistributed, or there are no load paths left to try.

I have been holding my tongue at the comments trying to suggest "sounds from above" = "collapse initiated above" due to this reasoning.

I expect this explains the strange noises occurring all round the building.

 The only thing I am unsure about is relative timescales. I expect most of what I have described above would only really take seconds to go from intact column > attempted redistribution > collapse; which then doesn't marry well with the several minutes of reported sounds. The only explanation I have is that the building was really really close to having enough capacity to redistribute the load, but was ever so slightly overloaded, hence cracking progressed slowly bit by bit, little by little at first. As capacity was lost though, this cracking would speed up as more and more load paths were comprised. Like I say, nothing to back this up, just my pragmatic view of what could be happening.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (these alternative load paths could be for instance all floor slabs dropping)

Very well described.
I had actually begun to visualize that scenario sometime in the last two days and you have explained the concept quite well. Thank you for posting when you did.
With a lower column failing, there could have been brief instances where the remaining sections of the column were in tension, pulling downward on the slabs above as the building developed alternate load paths in all the remaining slabs above, however momentarily.
The brief loss or even reversal of shear stresses in the slab around the perimeter of the columns may explain the seemingly clean punching shears seen along some columns.
Thanks,

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (The only thing I am unsure about is relative timescales.)

Then as the time progresses, this rater of lateral deformation starts increasing, and it reaches to the point of no return. This is the bifurcation point. Which explains that now even if the load reduces a bit, the column is never going to be stable. It is on the verge of collapse. As this lateral deformation rate increases, the differential deformation between columns increase and the slab tends to redistribute the load. Again for slab it takes time, because it is a flexible body (8" slab spanning 20-24 feet). As it redistributes, there will be cracks formed in the plaster / ceiling finishes. This can be observed in the ring video of one of the apartments. Like there were some initial spalls of plaster as this was happening.

As the column literally buckled significantly, now the stresses redistributed significantly in the slabs, but since these were flat slabs with no integrity reinforcement, and the brittle nature of punching shear failure, the collapse chain of series of punching shear failures was triggered and it was unstoppable unless it was encountered by a wall / bigger columns / columns with less tributary areas. I think this could explain why there was a pause of 7-8 minutes between pool deck failure and building collapse.

Now typically it is not that easy to buckle an RC column. So I am also interested in understanding what was happening at the step - beam column joint. Were there any ties provided in the column through the region of the step beam or not. And based on construction sequencing, I am assuming that for this 2.5' height of column at the step beam column joint, the contractor may have used 4000 psi concrete instead of 6000psi for columns. As there were no requirements for puddling back in ACI 318-77. So if these joints were not constructed and detailed properly, then it could explain why an RC column failed so easily.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

It’s me again. But before you begin the ridicule again, please hear me out.

The photo below shows the debris pile that was left at the end of the ramp for two days after everything else was removed. I believe that this was done because the Miami Dade recovery crew believed that the pile contained important evidence about the collapse. The importance of this evidence is clear from their using red paint to identify some of the objects and by their use of red cones connected by red tape on the ramp to keep away curious people who might tamper with the evidence.

I encourage you to zoom in on the objects marked in the photo to see what they are. To help you to do so, I have enclosed a digital PNG version of the photo that allows zooming in by rotating the mouse wheel forward after opening the document in Windows 10. You can also re-center the objects as you zoom in by clicking on the window and then moving the mouse from side to side or up and down. I have also enclosed in the following post a PowerPoint document containing the same photo that allows one to zoom in by using the slide button in the lower right hand corner. This document also allows one to selectively remove any annotation that obscures an object and to add new annotation as desired by the viewer.

What I found recently by inspecting this photo, and what you can see yourself by zooming in on it, is shown in the following figure.

One sees that there is a large amount of wire cable on the pile that does not seem to be evident in debris photos taken at other locations. I was able to trace at least 20 feet of this cable, although there is much more, perhaps over a hundred feet. Most importantly, I found that one end of it goes into the circular top of an object of interest on the debris pile as shown in the following figure.

I believe this object is the condenser of an air conditioning unit. Near this object lies a square piece of sheet metal with rounded corners that has a circular hole inside. I believe that this the metal top of the air conditioning unit. One would expect the cable to go through this circular hole as well. But one can see a slot in one side of the top that has allowed the cable and top to be separated. This slot could have been made by the recovery crew to allow easier inspection of the top, or could have been made by pulling on the cable by a power shovel while the top was still covered by the debris pile.

Now, I would wager that it is no accident that this cable extends into the internal condenser part of an air conditioning unit. Normally, the top of an air conditioning unit is covered by a wire grating that would prevent a cable from randomly penetrating inside. However, if one wanted to raise or lower an air conditioning unit with a cable, instead of putting it on a platform or using a lifting sling in some manner, it is easier to just remove the circular grating in the metal top and pass the cable hook through the top opening, then around a compressor support bracket at the bottom of the condenser, and then reattach the hook to the cable again. This alone would indicate that a human being was responsible for attaching the air conditioning unit to the cable.

So, why is the object of interest (whether an AC or some other object) still intact and still attached to the cable after the building has collapsed? Clearly, something went wrong during the raising or lowering of the object that prevented the person involved from detaching the cable. This something that went wrong could not have happened near the top of the building, because then nearly all of the cable would still be in the winch and not strewn all over the debris pile with the object still attached. Therefore, it must have happened near the pool deck. But if the winch malfunctioned in some way to cause the object to fall freely to the pool deck with the cable still attached, then the object likely would have been dented beyond all recognition by the collision with the deck floor. Clearly, the TikTok video shows that this object is still relatively intact. But what if the something that went wrong occurred just a few feet above the pool deck? This could happen if the cable was not long enough. In this case, the users involved might be tempted to gain a few more feet to safely put the object on the deck by tilting the crane at the top a little bit. But when this was done, the change in the crane’s center of gravity could have caused the crane to press against the parapet, causing a moment arm of over 7 feet (4 feet of parapet height plus 3 feet of clearance) with over 300 pounds of force to be applied. This may have caused part of the parapet to give way, sending it crashing down onto the most sensitive part of the building’s structure; namely, the beam between column 27 (column M10) and column M11.1. In this case, the object of interest would fall only the distance of one floor plus a few more feet, which would enable it to stay relatively intact. It would also have resulted in the object of interest falling midway between the hoist counterweights on the debris pile as observed in other photos because the object would have been pulling down on the hoist structure, thereby keeping it centered on the object.

1) It is likely that there was a second person at the bottom of the building as well as one at the top. This is likely because someone is required at the bottom to remove the hoist hook from the object and cart it away, while someone at the top controls the hoist. This second person was likely in cell phone communication with the one at the top. This would have allowed almost silent operation under normal circumstances after 12:00 AM at night. But this second person might have been seen by a surveillance camera having a line of sight over the patio area of the pool deck. This person at the bottom would have been exposed to the falling parapet and may have been injured or even worse. Nothing has been mentioned by the recovery crew about finding a person near the object of interest.

2) The amount of cable required would have been at least 120’ 8” to cover the distance from the penthouse roof floor to the pool deck below. An additional 8 feet or more would have been required to get over the penthouse parapet (4 feet tall), the height of the air conditioner (3 to 4 feet), and either a cable pulley or a winch (1 foot), thus adding an additional 8 to 9 feet. Therefore, the total cable length required would have been 129 to 130 feet. Most commercial winches have only 120 feet of cable, some have 130 feet, but very few have over 130 feet. Therefore, the amount of cable needed was right at the limits of most available winches.

3) With the pulley or winch needing to be 8 to 9 feet above the penthouse floor, the hoist would have been quite tall. Also, it would have needed to extend at least two to three feet over the parapet to clear a 3 foot square object like an air conditioner, so it would have required a counterbalance over 8 feet long with weights greater than 300lb x 3/8 = 100 lbs to stabilize the hoist in two directions. Two hexagonal weights on rods were found on the debris pile that could serve this purpose. Also, this large hoist would likely have been present when the building inspector was on the roof the day before the collapse, so he should be able to give a description of the hoist.

4) A winch would have been attached to the hoist structure. This winch would have fallen to the pool deck below with the hoist structure, probably causing the winch to be seriously damaged. An object was found on the debris pile that appears to be this winch, with the motor and cable spool separated from the housing. However, no other parts of a hoist structure have been observed except for the two counterbalances and possibly a pulley.

5) Operation of a hoist on a roof requires that the hoist have a tie-down cable to a secure building structure to prevent it from falling. There was no such secure building structure on the penthouse roof near the hoist at the time. Therefore, the workers may have used the aluminum framework of the air conditioner mounts as a tie-down structure. Evidence of an aluminum framework with a second air conditioner attached can be found on the debris pile at the end of the ramp.

6) Could the falling of the penthouse parapet wall above and its crashing to the deck correspond to Maud’s first stage of collapse? The second stage of collapse has been identified as being caused by the falling of the pool deck, which might have taken place after a short pause.

7) Could the “knocking sounds” or “hammering on the roof” heard by a tenant and by the night watchman before the collapse have been caused by compressed air guns being used to remove air conditioners from their mounts prior to moving them?

8) Could the weird smells noticed by some tenants have been caused by the refrigerant being released from the air conditioners that had fallen? This refrigerant is a gas that normally has a faint smell like either ether or chloroform that some people might find to cause a disagreeable odor. Each air conditioner has about two to three pounds of this gas inside that takes about a half hour to release completely. With a total of about sixty or more air conditioners on the roof falling at the same time, this would have caused over 150 pounds of this gas to be released all at one time, which would have been noticeable throughout the collapsed building.

9) There may be a witness who can tell us who was on the roof that night. The security desk employee should have seen anyone who entered the elevator after hours while wearing working clothes. And this same security desk employee may also have seen them exit the elevator to leave the building after the pool deck collapsed, which he/she should also have seen by watching one of the security cameras. Has anyone asked the security employee about these topics?

I will leave it to others to explain who may have been on the roof that night to trigger this sad sequence of events because of potential liability concerns. Suffice it to say that the trigger for the collapse was likely an industrial accident created by carelessness and stupidity, and not merely by structural deficiencies as bad as they were to everyone’s agreement, including my own. Without this trigger, no one knows how long the building could have remained standing with all its deficiencies. The case is equivalent to an old and unhealthy person being run over by an automobile driven by a careless driver. No matter how old or how unhealthy the old person is, the cause of death is still an automobile accident caused by a careless driver. One can introduce new health measures to keep an old person functioning longer, but only by stopping careless driving can one prevent automobile accidents that cause the death of older people.

Enclosure 1 (1st post below):
PowerPoint document: Overheads of debris pile at end of ramp (zoom with slide in lower RH
Enclosure 2 (2nd post below):
PNG photo: Overhead of debris pile at end of ramp (zoom with mouse wheel & re-center by moving mouse)

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I'm waiting for a report from someone who was on-site.
In the meantime, I'll see your collective speculations and raise you two guesses and a maybe.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (column joints trying to hold together as a Vierendeel truss and taking up moments they are not designed for.)

The Vierendeel truss concept is most interesting. Losing a lower column in a structure like this could leave a V truss with 12 levels of horizontals and columns forming a large grid. Loss of a single interior column could be balanced and not create shears in the single remaining column stack above. Negative moments at the perimeter of the unsupported bay would cause shears in the remaining columns which would be distributed to the remaining columns thru direct tension and diaphragm action at each floor.
This could supply the "redundancy" not evident in the system. It likely failed in this case because the slab reinforcing was spliced at the column strips and continuity reinforcing was inadequate. And the columns appear to have little capacity for shear and moments.
A comprehensive study of this failure should investigate this redundancy thru V truss action.
One can envision designing this capacity in future designs.
Good call.
Thanks,

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (MarkBoB2 (Electrical)20 Aug 21 17:54)

It’s me again. But before you begin the ridicule again, please hear me out.

The "AC" seems to be the size of the cones. Either large cones or small AC?

edit: It looks as if this is a screen shot from a video. Could you please post a link to the video? Thanks very much!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

MarkBob2, I'm sorry I have not read the full text of your post, but looking at the photos I just can't make my eyes see any of the things you seem to see. As best I can tell all you are pointing at are smashed up bits of concrete and rebar. I really can't fathom how you are making anything different out of these photos.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

SFCharlie, the full video is titled "Recovery Efforts Continue at Surfside Collapse Site", and can be found at https://www.youtube.com/watch?v=jI6Up5Nv70c. The scene from which this photo was taken occurs at 4:45 into the 5:02 long video.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (MarkBoB2 (Electrical)20 Aug 21 20:20)

SFCharlie, the full video is titled "Recovery Efforts Continue at Surfside Collapse Site"
Thank you very much!

SF Charlie
Eng-Tips.com Forum Policies

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Is that cable? I just thought it was the thin rebar (from slab bottom or something) and it was pale because it was dusty. But it does kind of look like cable.

I'm not convinced by the image interpretation though and I still think it's very unlikely that something like that fell right outside 111's window without that being in 111's story. Or that an operative was on the pool deck trying to bring an AC (or anything else) down after midnight, again with 111 mentioning it.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (8) Could the weird smells noticed by some tenants have been caused by the refrigerant being released from the air conditioners that had fallen? This refrigerant is a gas that normally has a faint smell like either ether or chloroform that some people might find to cause a disagreeable odor. Each air conditioner has about two to three pounds of this gas inside that takes about a half hour to release completely. With a total of about sixty or more air conditioners on the roof falling at the same time, this would have caused over 150 pounds of this gas to be released all at one time, which would have been noticeable throughout the collapsed building. )

Markbob2, I will only comment on your item 8, as I have lots of HVAC hands-on experience that conflicts with your number 8 narrative. I don't know where you got your information for number 8, but it is so far off, I have to furnish correct information.

Most of the roof AC units you are referring to are residential units, which would contain either R22 with mineral oil, or R410a with synthetic oil. Neither of those refrigerants or oils produces the 'weird' smells that would be noticed by anybody. What smell there is dissipates very quickly and size of hole determines how fast the refrigerant vents into the environment. So cross that one off your list.

My current Rheem 3 ton residential HVAC units have about 19 lbs of refrigerant in each of them. One is more than the other due to longer line set. I know this because I weighted the refrigerant in when I had to repair an outdoor unit leak. The manufacture label contains the amount of refrigerant pre-charge in the outdoor unit, and tells you how much refrigerant to add for each foot of line set beyond 15 feet (depending on line set size). So 3 lbs or a normal residential home system is way off. Think about how long the line set is for first floor air handler with a roof condenser. The other problem is that over the years depending on manufacture or compressor type or size of coils, the amount of refrigerant can vary a lot. My systems are 12 years old, and newer ones take less refrigerant than my 410a systems. Again your assumption is so far off, I have to offer correct information.

Bottom line, Throw out your number 8 assumption all together. It is wrong and unsupported by real world data.

I will be honest, all I did was scan your long list of statements, and this one caught my eye because I know it is 100% wrong and can validate that it is wrong, so I felt compelled to correct your assumption.

Not trying to be critical, but it sure would help credibility if things like your number 8 were actually even in the ballpark of being realistic without easily seeing it is way off. I only speak for number 8, since I am expert on this subject.

Edit: BTW, you found a winch. The roof hoist would not have used a winch. It had to be a hoist rated system for overhead lifting. Winches are for horizontal pulls like pulling a car up onto a trailer or pulling a 4WD out of the mud.

Edit2: HVAC guys use cordless impact drivers, drills or hand tools to loosen and tighten nuts, bolts and screws. Not dragging a compressor around to use air tools.

Edit3: Most of oil is in outdoor unit on roof, and that is where the higher percentage of refrigerant would be. Once a line shear leak developed on roof, the refrigerant would escape to atmosphere quickly.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

If you want to talk about suspicious orange cones, I'd be more interested in talking about the one seen on the police body cam, that was located right beside the edge where the slab broke off in the parking area. Was it there because there was already some damage in that area?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Sincere thanks to all who have described various possibilities related to the building’s load redistribution. It seems so impressive that the building adapted and adapted for over two hours in order to keep its balance, almost managed to find it, and then lost it after all.

Am I correct in thinking that the first collapse at 1:10 was the straw that finally broke the deck’s back? Or could that simply be coincidental rather than causal? I understand we are speculating. My interest is in understanding the various ways we can understand the sequence of events.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (StructuralMadness (Structural) 20 Aug 21 17:27)

... for this 2.5' height of column at the step beam column joint, the contractor may have used 4000 psi concrete instead of 6000psi for columns. As there were no requirements for puddling back in ACI 318-77.

I refer to dwg "S5 of 14" from R1 of the Surfside document package (or page 31 of the PDF) which I believe is the revision closest to construction.

Along grid 9.1, a slab step of 1'-6" is specified, altered from other revisions using 2'-6", and would effect columns I, K, and M, where column L would only see a 7" step. This step revision also places the pool deck elevation at +11'-10", at par with the above ground parking as opposed to the alternative arrangement where the parking was at an intermediate elevation between the building slab and the pool deck slab.

In your video, I do not recall you mentioning the parking adjacent to the thirty foot span between columns under the pool deck nor the planters separating the pool deck from the parking, both of which impinge on the weakest area of deck slab. Can you update your model to account for this extra load?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

For those Mechanicals on this thread - some credit, I think.
- - - - - - - - - - - - - - - -
1875 Ward's Castle - William Ward, a mechanical engineer living in Port Chester, New York, chose to build an all concrete house. It was the first reinforced concrete structure to be built in the United States. When it was completed, neighbors expecting it's imminent collapse called it "Ward's Folly", but after years of little wear and much comfort, it earned a new, well-deserved appellation, "Ward's Castle".

Source: http://www.dupontcastle.com/castles/wards.htm

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Debirlfan

I believe that cone was used to reserve certain parking spaces on the upper level.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Vance Wiley (Structural)20 Aug 21 22:55 )

Ward's Concrete Castle would have been great in summer before Air Conditioning, but I am not so sure it would have been very comfortable in winter?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Optical98 (Computer) 20 Aug 21 23:02)

I believe that cone was used to reserve certain parking spaces on the upper level.

Entirely possible. Given where it was located, it did seem suspicious.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (All About Money (Aerospace))

Not trying to be critical

I think I can be a little more critical. A 3 ton condenser unit weighs maybe 150 lbs shipped with a charge in it. I don't know what the terminal velocity would be but they would catch some air given the grid and radiator fins. If a single condensor hitting the ground (or the deck) was even felt as a vibration in the structure I would be surprised. I am not saying these things would even implode or disintegrate when hitting the ground from that height. You could probably rebuild it. I mean a 35 inch direct view tv set from 1990 weighs twice as much.

Edit: about 22.6 kJ at impact at most for a 3 "ton" unit weighing 150 lbs. At 93 km/h with no wind resistance. Someone will correct me if I'm wrong. Crumpling would absorb some of that energy I assume. Seriously though no one would rebuild it because the coil would be toast, but you might be able to salvage the compressor!

Edit: one to many kilos (k double transposed)

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Contemporary drone shots. Surfside is opening up the west lane of Collins. The foundation does not appear to be braced.

https://www.local10.com/news/local/2021/08/20/lane...

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (zebraso (Mechanical)21 Aug 21 11:22)

Edit: Perhaps a 3 lb refrigerant system in flight? 😏

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (MaudSTL (Computer)21 Aug 21 13:57)

It seems to me that there should be a larger right of way along Collins Avenue, such that a private owners building’s foundation wall did not affect the public roads?

Or there should be adequate setback from property lines before digging below grade level?

It seems a building failure should not compromise public roadways.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (All About Money (Aerospace))

3 lb

As a prop? yeah. ha. They got that to look pretty real. David Letterman used to do a gag where he dropped stuff off of the Ed Sullivan (I think) theater. It was never very impressive (mostly anti-climatic). It wasn't 13 stories either AFAIR. I wouldn't doubt he actually dropped an ac unit. Of course they took all the proper safeguards. I am sure he dropped things that weighed at least 150 lbs. Generally most things don't disintegrate into bits and pieces unless they are really brittle. AC unit? nah.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

noticed in the vid local10 news report (link that MaudSTL provided [thanks, MaudSTL])small and large pump dewatering (I'm supposing)trucks.
I'd post the picks I had screenshot from the report vid, as a convenience, but don't know the copyright protocol for the forum. sorry. easy enough to view the vid.
of course, don't know exactly when the drone vid was taken. could have been stock footage, maybe.
but I noted the location of the trucks????
in a case, like this, would they haul and dump the water?
or consider the use of the well, which was possibly never permitted?
also, wondering the ratio of sea water to fresh?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Re: Letterman. The building was 7 stories. Amongst other things, there’s a 250 lb safe coming off it at the 2-minute mark.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Regarding sounds.

Can punching shear failure occur in slow motion?

Back when Dik posted the pic of the MC core sample it didn't register w/ me at the time just how odd that sample was. It wasn't until I watched Building Integrity's video, where he mentions that ALL of the cores looked similar, with rebar loose within the core, that I realized my oversight.

Picking up from Building Integrity, IEGeezer points out above just how stressed that one pool deck column line was (the one that is also missing a drop down beam), as well as having the smallest columns. So if we assume that the slab around column K13.1, also the most highly stressed area, failed in punching shear first, could this occur in relative slow motion? By that I mean, not being immediately obvious, except for the sounds. Could it then progress to column K12.1, again not being obvious, except for the sounds? If so, at this point it would begin to impart thru catenary action horizontal loads onto the main building column (this by the way was previously posited way back in the thread).

RandomTaskkk addresses column failure and load redistribution leading to sound generation throughout the building. Could a sustained horizontal force on the column also lead to sound generation? The time frame of all this is what I don't understand.

Then, just speculating here. Garage level still may look relatively intact. Pool slab is still pulling on column, but nothing has fallen yet. Now slow motion punching shear progresses east from column K13.1 towards the pool and the construction joint that exists in the deck slab. At some point that section fully drops and becomes visible from the garage ramp. Then other sections of slab begin to drop and all hell breaks loose.

Of course many things are POSSIBLE, but I thought I'd just add that to the mix.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Spartan5 (Civil/Environmental))

250 lb safe

Thank you. A little perspective I guess. I thought I just read EST was 13 stories after I said it wasn't whatever. Actually that would make a difference with m/s/s and all. I think he jumped the shark after the velcro suit.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

EST proper is 13. But wherever they were dropping from was 7. I counted them. But I don’t have a PowerPoint of it for you :)

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (TheGreenLama)

Regarding sounds.

Can punching shear failure occur in slow motion?

That’s my beat guess for the noises. Slow progressive failure of the deck as it worked its way towards the building. Possibly originating at a construction joint nearest the pool. Culminating in a more rapid failure as it hit the weak spots in the garage and near the planters. Which then brought the rest of the building down within a couple of minutes.

That would explain the noises growing louder. And how elements of the initial failure weren’t visibly apparent. Unless you
Happened to be looking at the pool from a balcony perhaps.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Spartan5 (Civil/Environmental))

That's good. Makes sense also. As fuzzy as my memory was on that stunt I could not have imagined from memory that they were dropping crap from 13 stories. PPT. yeah right.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Having mentioned possible slow motion punching shear failure, let me also add several questions surrounding that scenario:
1) From photos of the pencil-like column tops in that area, the fact that so little slab concrete appears to have been engaged makes me wonder how 'slow motion' the failure could have been.
2) This may have been discussed before, but you'd think the fire suppression lines in garage should have become activated.
3) For the pool slab to hang/drape it must be supported somewhere. That would require a patchwork failure at first.
EDIT: 4) Lack of integrity reinforcement above the columns.

Unless, as you say Spartan5, the failure progressed from the rear of the garage towards the building. But then all that creaking in the building remains a mystery.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (TheGreenLama)

But then all that creaking in the building remains a mystery.

There isn’t much to me that’s definitive in another of that reporting. Most of it seems pretty inconsistent.

As for the pencil columns, it makes me wonder how the deck stood for 40 years. So it also seems possible that there was enough strength in those poor connections to allow for some load transfer and incremental failure as well. What would it sound like as each of those columns popped and the deck sagged/collapsed a bit more?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
A graphic tool for analyzing the debris pile with red paint on objects located at the bottom of the resident parking garage ramp.
With glossy photographs with circles and arrows and a paragraph on the back.
(Oh No, Not another powerpointy du-da)
from the 1979 plans, the location of approximate square of columns.

1979 dimensions of approximate square of columns.

Rectangle showing the 1979 dimensions on the outtake from the video.

zoomed in on the pile overlain with a one foot grid in blue.
Not to put too fine a point on it, the objects in the pile are small.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

SFCharlie, Thank you for all your work above. I agree with the scale you show. But your green square doesn't agree with any of the objects that I have identified. The downward-pointing arrow to the left of your green square is what I have believed to be an AC condenser. And the arrow below it pointing to the 11:00 o'clock position I believed to be the top of the AC. Both of these objects are tilted, so it is difficult to get a good idea of their dimensions. But I agree that they are smaller than I expected. I measured that the diagonal of the top was about 20 inches. And I measured that the diagonal of the condenser was about 22 inches, with a hole about 10 inches in diameter. This probably means that this object is not an AC. Do you have any ideas of what it may be?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (MarkBoB2 (Electrical)21 Aug 21 21:07)

your green square doesn't agree with any of the objects that I have identified.
Your very welcome. I just do it for the fun of it...
The green square is the size of the base of one of the traffic cones. I largest traffic cone I found on google was 36" high and 14" square at the base.

edit: I agree, they are probably not part of an air conditioner. If I were you, I would use power point to draw lines or arcs to show the edges on the objects. I use the rotate shape to align the pp shape with the image. Also, after selecting a shape, I use "shape format" to "edit shape">"edit points" to get everything to line up. Sometimes this helps my mind recognize stuff.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

SFCharlie, I agree with your cone dimensions. This was how I estimated the dimensions above, by comparing them to the cone dimensions.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Please ignore my knucklehead mech engr question (although I have a lot of failure analysis experience, just not on reinforced concrete):

So it seems a popular theory is that the columns punched through the patio deck and as it failed it tugged on some main building columns which were now damaged at failed slab joint, and now those columns had much greater unsupported length. Failed in buckling, especially with the discontinuity where the slab used to be attached.

So the question: If that patio slab was so degraded that punch through could happen, would you not expect to see deformation on the upper slab surface right over the column, for at least some period of time? With the standing water common on the patio surface, you would expect to see bulges or dry spots right over the columns??

As the column to slab joint overstressed one would think there would be deformation before failure?

I'm having trouble with how concrete behaves in failure and this time element between clues and total failure. I would think that failure would be more sudden than drawn out over several minutes.

Maybe just showing my ignorance...

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (MechinNC (Mechanical)21 Aug 21 23:00)

I'm having trouble with how concrete behaves in failure and this time element between clues and total failure
Many of us are having trouble putting the witness statements and what limited evidence there is together into a straight forward understanding of the collapse. That why MuadSTL put together a spreadsheet (link upstream) of the times of the witness experiences. The YouTube channel "BuildingIntegrity" has a video that takes one through the garage video tour under the pooldeck, showing the cracking in the structural bottom layer of the deck slab. It's necessary to have an awareness of the history of the pooldeck. Apparently, the as built had a layer of non-structural concrete with a brick pattern stamped in it. Then a layer of sand and then pavers was installed sometime latter. The sand may have hidden the distortion going on underneath.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (MarkBob2)

Do you have any ideas of what it may be?

Literally every 'chunk' in the "Slide 10" photo is just smashed up concrete.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (MechinNC)

If that patio slab was so degraded that punch through could happen, would you not expect to see deformation on the upper slab surface

A YT channel named Construction Engineering & Failure Analysis (https://youtu.be/djePOXALegM) talks about this. You can actually see what looks like deformation in the pool deck in some of the photos. Or maybe it was designed that way for drainage.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Jedidad (Computer)22 Aug 21 13:02)

Maybe that deserves a second look.
The tile installation would not have been so abrubt while the weight of the installation could have set that off in the days/months after.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Sym P. le (Mechanical)22 Aug 21 15:38 )

The tile installation would not have been so abrubt while the weight of the installation could have set that off in the days/months after.

When Demented was looking thru all the maintenance and repairs, one was the tear out of the pool gutter system and installing a new gutter system which appeared to be higher in elevation than the original one. I think when the raised the perimeter of the pool and hot tub, they added probably more sand to raise the patio tiles to match the elevation of the pool and tapered the deck from new pool curb height into the rest of the patio deck. I know in some pictures I have seen, way back in this long thread, it looked clearly like the area around the pool and hot tub was higher elevation, and tapered back into the rest of the paver level on patio deck side of the pool.

I don't think what you are seeing is structural deformations below.

Perhaps Demented has the info handy to confirm my memory?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Jedidad (Computer)22 Aug 21 13:02)

A YT channel named Construction Engineering & Failure Analysis

"Construction Engineering & Failure Analysis" works very hard to find sources of information, and, I guess it's not surprisingly, keeps his sources very close to his chest, refusing to share them. In searching for myself, I discovered this site. He scours this site for input. I strongly suggest new posters read or at least scan previous posts of this thread!

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

2

#### Quote (SFCharlie (Computer)(OP)22 Aug 21 16:18)

"Construction Engineering & Failure Analysis" works very hard to find sources of information, and, I guess it's not surprisingly, keeps his sources very close to his chest, refusing to share them. In searching for myself, I discovered this site. He scours this site for input. I strongly suggest new posters read or at least scan previous posts of this thread!

I first found "Construction Engineering & Failure Analysis" You Tube videos back either on FIU Bridge Collapse or Hard Rock in NOLA.
After suffering thru one of his videos, I have never listened to his mind work, out loud, in real time on You Tube again.

I highly recommend this Forum, and You Tube Analysis from sources like "Building Integrity" over a lot of other chatter on the internet. Yes you might find some good information or alternative ideas or pictures on other sites, but you must sort thru the noise to find a valid signal!

Edit: But problem is, a lot of the conclusions or ideas are provided based their cited, but not disclosed, calculations and assumptions. Point is there is a lot of difference of opinion out there, but no none has hit the ball out of the park yet! Further Miami-Dade has locked down the information sources, thus there is not much to go on with grainy pictures and the screened and selective documents that were released to the public.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Lizard7709 (Civil/Environmental)23 Jul 21 11:13 (post 8))

I also saw this of interest. Waterproofing, paver installation and garage repair in 1996.
I don't know if this is the earliest...

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I said "MAYBE"!!!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

> You can actually see what looks like deformation in the pool deck in some of the photos. Or maybe it was designed that way for drainage.

I don't think that's deformation, you'd expect to see signs of it against the back wall if the slab had sagged - and although the attachment to that back wall was pretty minimal, it was attached, so that's also the least likely place to see initial deformation.

I think they didn't lay the sand and topping stones flat, either deliberately for drainage or through incompetence.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Yes you might find some good information or alternative ideas or pictures on other sites, but you must sort thru the noise to find a valid signal!
But problem is, a lot of the conclusions or ideas are provided based their cited, but not disclosed, calculations and assumptions. Point is there is a lot of difference of opinion out there...

Youtubers get paid by the number of viewers so when a guy shows up here promoting his own videos while also knocking videos from other youtubers, it kind of makes me suspicious of their motives. They talk in circles and never allow themselves to be pinned down with real numbers and calculations. Prove your assertions with facts and don't run off to your facebook page and try to get me banned there for calling you out here...to your face.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Youtubers get paid by the number of viewers so when a guy shows up here promoting his own videos while also knocking videos from other youtubers, it kind of makes me suspicious of their motives.)

I think you are talking about me here. So first to clarify, I have been making hard core engineering videos on and off for 2 years now. I have a blog for about 8 years, written 600 answers on structural engineering with calculations in a lot of cases. For “ZERO” money. My YouTube channel isn’t monetized yet. It takes a lot of effort to get it monetized and you have to post videos regularly. Again I can’t do that because of lack of time.

Now stealing about content, I think you should notice that I made the entire video 45 minutes long. Talked about calculations in there, with a structural model of pool deck slab which showed failures, also discussed how the pool deck stayed up so far and brought in a research paper by “Hawkins and Ospina” for punching shear failure that was published in 2017. I did not bring in any technicalities because I wanted it easier to understand for the general population. Again it is not about exceeding the code specified capacity but it is about reliability analysis of materials and their actual capacity vs the code calculated capacity. I also brought in the concept of flexural induced punching failure and how crack propagation in flexure can compromise punching shear capacity as it loses aggregate interlock.

It was 2 weeks after the video I posted, BI released their video on the engineering failures on design side. I haven’t said that he stole my content because any good structural engineer can easily connect the dots and see things clearly. I am only questioning 3 points which doesn’t make sense from structural behavior/ member capacity standpoint.

Now, if I wanted to earn a lot of money, then Could have created 10 different videos with 100 different speculations, but I just finished everything in one, with all the dots connecting together. Because again monetization is not my goal here and it has never been. I earn enough for my family that I don’t have to put extra efforts to earn money, in fact I donate money annually and pay for under privileged child education in developing countries. So don’t start bashing someone without any reason.

Now I have no use of you and your comments anymore. Peace ✌️

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

SF Charlie,

Do you think the "#31...#53" etc, are the parking spaces?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (All About Money (Aerospace) I first found "Construction Engineering & Failure Analysis" You Tube videos back either on FIU Bridge Collapse or Hard Rock in NOLA. After suffering thru one of his videos, I have never listened to his mind work, out loud, in real time on You Tube again.)

I would second there. I do understand he finds a lot of information, but from engineering standpoint he hasn't made a lot of sense personally speaking. I watched one of his video where he said "I don't know what these guys on YouTube calls Puking shear or something." And that's when I stopped watching his videos.

Now going back to "Sounds"

I like your idea of Vierendeel truss action, but when we hear Nir's interview, he mentions that as soon as his mom went out to complain about noises, that's when they heard a loud boom and the cars caved in. Here is the link to his video. So, if the noises were coming from above, prior to complaints, then does it mean something failed prior to deck collapse? It is the timeline and witness's documentation about hearing noises vs the deck collapse that doesn't make sense. Everyone knows that deck collapse prior to the building, and the creaking noises and CMU wall cracks could have occurred only when the building was trying to support the buckled / failed column. Then how does the noises coming prior to the deck collapse make sense?

Edited to paste the link of the interview: https://www.cbsnews.com/video/son-shares-how-famil...

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

don’t start bashing someone without any reason.

My reason was clear in my first post to you.
You failed to address the sleazy move of destroying my reputation on facebook.

Yeah, we're done.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Optical98 (Computer)22 Aug 21 20:38)

Do you think the "#31...#53" etc, are the parking spaces?
I don't know anything you don't, but seems like an obvious guess

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (StructuralMadness (Structural)22 Aug 21 20:04 )

I also brought in the concept of flexural induced punching failure and how crack propagation in flexure can compromise punching shear capacity as it loses aggregate interlock.

If you go back to when the Association was complaining that 87 Park Construction vibrations were shaking CTS, you have to wonder if they are saying the structure is swaying? What effect was this having on the slab to column connections/joints throughout the building?

You also have to wonder why some folks had to float a very thick layer of thickset mortar to level their condo floors before installing hard tile floors?

So, I think your flexural induced punching failure is definitely an interesting possibility and seems it would explain the swaying from construction next door and basically lead to the building movements were basically tearing the joints/connections apart over time a little by little?

Was the swaying induced by skinny columns and the poor punch shear reinforcement just made the joints/connections more vulnerable?

It is not clear to me that the building was not having problems before the patio deck, but their marriage with the common beams at drop slab area led to all movements affecting both the patio deck and the building.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (StructuralMadness (Structural)22 Aug 21 20:43)

Then how does the noises coming prior to the deck collapse make sense?

1. I don't know...

2. 1st punchthrough "catenary action" 2nd punchthrough "catenary action" 3rd punchthrough "catenary action" 4th punchthrough ???

I never heard of "catenary action" before, catenary is the name of a curve in my world???

#### Quote (ScienceDirect)

Catenary action is a load mechanism that is developed to resist the additional loads as a result of sudden column loss and prevent disproportionate collapse. Buckling restrained braces (BRBs) have been widely adopted as a dependable lateral load mechanism since the early 1990s.
Catenary action in steel framed buildings with buckling restrained braces

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer)(OP)22 Aug 21 20:16)

I don't know what if anything can be gleaned from this...
Champlain Tower Cars.. Must watch

About 30 seconds in, the red car in your video reminds me of the first muscle car era. For Example, I offer this image

More Info: It is actually a Train Blower and he blew head gaskets just blipping the throttle. Not an Engineer Designed Bolt-On! Just a junk yard find, that they decided to bolt on..... Or as they used to say, this was NOT a 'Blue-Printed' System Upgrade for this Engine!

https://www.musclecarszone.com/supercharged-chevy-...

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
Swaying and lack of sheer walls seem connected to me?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (All About Money (Aerospace)22 Aug 21 22:37)

the first muscle car era
Is that a compressor between the carbs and the engine compartment??? Looks more like todays electric motors only much larger?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

SFCharlie, Yes the HVAC technicians use the compressor on top of the motor to run air tools while on the job! That way they can write off their auto investment!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer)(OP)22 Aug 21 22:40 Swaying and lack of sheer walls seem connected to me?)

Agree, but without sheer walls, it is left to columns/slabs to provide lateral support is my understanding.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I like your idea of Vierendeel truss action, but when we hear Nir's interview…

This is Thread #11 and you’re late to the party. So, to help keep us from going down a rabbit hole we’ve already visited, here are the key events that surviving witnesses reported in many corroborative sources which are cited in the second tab of the timeline spreadsheet.

All of these events have multiple witnesses and credible time stamps or ranges. That is why some engineers are considering structural failure scenarios that are compatible with this sequence of events.

1. 11 PM to 1:10 AM, knocking sounds like hanging pictures or construction (111,) increasing in intensity over time.
2. 1:10 AM, a collapse like a collapsed wall (111) or something with the elevator (lobby.)
3. 1:15 AM, deck collapse viewed as a garage collapse (seen from the lobby, and heard from 111 and the elevator.)
4. 1:22 AM, building collapse.
We have already discussed that the perceived direction (from above) of the first two events is not necessarily meaningful.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (All About Money (Aerospace)22 Aug 21 23:01)

it is left to columns/slabs to provide lateral support is my understanding.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Literally every 'chunk' in the "Slide 10" photo is just smashed up concrete.

That area near the garage ramp really got crushed badly. The east side of the building pancaked right on top of it. It's not going to be easy figuring out what happened to the objects in the tiktok video.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
Do we have a floor plan with unit numbers that I missed?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie)

Is that a compressor between the carbs and the engine compartment??? Looks more like todays electric motors only much larger?

It's a Roots-type supercharger--intertwined rotating dual lobes--sorta like gears. A nice thing about them is that there's no turbo lag.

spsalso

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

That's a roots blower from EMD engine. These engines have a blower for each bank. The most powerful roots blown engine was 2200 horsepower so the pictures engine would support 1100 horsepower which is quite reasonable from a big block. Just don't rev it beyond 900 rpm.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Detroit Diesel used that type of blower to scavenge the exhaust gasses from the 71-series 2-cycle engines.
There was a 2-71 Blower, a 3-71, a 4-71, a 6-71 and an 8-71. The 6-71 was the most widely available model and was used on many high performance cars. To serve the market for a larger displacement blower, after market shops developed a model 10-71 blower, but GM never made a 10-71 engine. The 10-71 was after market for high performance engines only.
edit. Now available for racing are 14-71, 16-71 and 18-71 blowers. These were never used on Detroit Diesel engines. The 12-71 engine used two 6-71 blowers and the 16-71 engine used two 8-71 blowers.
Roots type blowers were also manufactured in other displacements for industrial use.
After WW2 there were thousands of military surplus 71 series engines on the market, a large number were 6-71s from landing craft.
Surplus 6-71 blowers were cheap and plentiful and much sought after by performance builders.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Just remember that the 71 indicates the displacement per cylinder. These were some of the first modular engines. Shortly after, Kettering spearheaded the development of a medium speed engine for EMD that was 567 cubic inches per cylinder and eventually evolved in to 645 and 710 cubic inch per cylinder models.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer)(OP)23 Aug 21 02:09)

Do we have a floor plan with unit numbers that I missed?

There was one. Start in the northeast corner and go counterclockwise.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

New Simulation is the most realistic I've seen yet. They don't give any info on how it was done though It does appear there was an attempt to make it consistent with the debris pile.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

When Demented was looking thru all the maintenance and repairs, one was the tear out of the pool gutter system and installing a new gutter system which appeared to be higher in elevation than the original one. I think when the raised the perimeter of the pool and hot tub, they added probably more sand to raise the patio tiles to match the elevation of the pool and tapered the deck from new pool curb height into the rest of the patio deck. I know in some pictures I have seen, way back in this long thread, it looked clearly like the area around the pool and hot tub was higher elevation, and tapered back into the rest of the paver level on patio deck side of the pool.

I don't think what you are seeing is structural deformations below.

Perhaps Demented has the info handy to confirm my memory?
Correct. That section of slab was original height. Barely any sand was used there to match the pavers. The surrounding areas were raised. Around the exterior of the main building, it was the same. A slow taper that allowed water to collect and pool at the border of the building/deck.

Don't have it handy, but I can dig through the stuff later. However, I did find a series of failed inspections on the rebar placement at that location but it was subsequently approved based on yet another letter from a PE. Same PE and construction firms involved in the other work. Still trying to get as-builts, but those don't exist per the town. I've kinda given up as I've exhausted everything I can dig through being a nobody.

Between the walls falling over in hurricanes, rebar added to an existing design, rebar removed from an existing design, additional sand/paver weight, delaminated slab, epoxy repairs and mortar patching, and pile driving next to that location, I think it's a good location to investigate.

After reading through everything I have, to me it looks like the pool deck restoration work was never finished during a dispute and the pool resurfacing work continued as planned. A 3rd contractor had to come out to fix loose tiles left all over after the hot tub work before the final approval was given by the inspector. Hurricane damage repair work at it's finest.

Planters used to be here too

#### Quote (IEGeezer)

That would be about 45 inches tall. Where did you get that the big planters were 4 ft by 8 ft. In this picture, they look roughly square as they do in the Morabito Consultants drawing I referenced.
4x8 is just the ref name of them I have seen called out on original drawings and contractor plans. There is a slight chance 1 planter, though I am not sure which one, was built by placing CMU bricks along the perimeter of the existing and the original was demod internally and used as fill. This was around the same time they were modified to 45" tall, which was to replace tapered cracked cast concrete caps.

Also waterproofing was there. Just poorly done and trapped water instead. I'd have to dig up the spec sheets again but we've got the weights there.
I don't think geofoam was used either. I've found 0 mention of it in any of the repairs/rebuilds. Rootballs of old palms and seagrapes were likely left in.

The additional sand and raised/clogged drains on the deck was also a massive area for water to pool up beneath the pavers.

This building took quite some damage from a few hurricanes it seems. Has anyone run a simulation on hurricane windloads of this building?
Lets all do the twist!

Disclaimer:
This is NOT a photo of champlain towers south. I'm still told photos of the work there no longer exist. This is partially the same crew that did the work on CTS's balcony, deck, and beam repair. Concrete lab tests were also not done it seems and most concrete was mixed/pumped on site with bagged cement. Processes and work habits typically don't change job to job, especially when the PE and contractor have a relationship.
Concrete experts, does this look right at all? Looks a wee bit wet to me.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Demented (Industrial)23 Aug 21 09:37 )

Concrete experts, does this look right at all? Looks a wee bit wet to me.

It appears no vibration needed with that mix, all the aggregate has fallen to bottom with only watery cream 'floating' to the top?

Assuming there is aggregate in that mix?

Re-defines Layered Pour?

SFCharlie, I am guessing the dog balancing spinning 'Flat' plates with the pencil columns was on the Ed Sullivan Show, as I seemed to remember that act?

SFCharlie,

Unit numbering >

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Sym P. le (Mechanical)23 Aug 21 04:12)

There was one. Start in the northeast corner and go counterclockwise.
thanks

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Optical98 (Computer)23 Aug 21 15:15)

Unit numbering
Thanks very much!

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (waross)

Detroit diesel also made a Series 53, Series 92 and Series 149 in their blown diesel engine series. One of our farm tractors had a 4-53 diesel that you could hear from 2 miles away. These were two cycle engines and were made in 3-53, 4-53, 6-53, 8-53 and 12-53 engines with 53 cubic inches per cylinder.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

2

#### Quote (If you go back to when the Association was complaining that 87 Park Construction vibrations were shaking CTS, you have to wonder if they are saying the structure is swaying? What effect was this having on the slab to column connections/joints throughout the building?)

Buildings do shake in general when there is a construction going on at a site nearby. Currently I am living in an apartment right next to a construction site so there were periods of intense shaking, but that doesn't not affect a building's performance significantly because the buildings are design to handle significant amount of lateral loads. Either wind / seismic. The vibrations though as experienced by occupants must be high accelerations (occupants can feel anything over 10 milli gs as lateral acceleration) and anything over 2.5%g as vertical accelerations, so any acceleration vertically higher than this will lead to some magnitude of occupant discomfort and people can start complaining. But the building deformation corresponding to these accelerations is very minimal. If the vibrations because of construction site work are significant then you may face some significant damages structurally. And if that happens, then we should also see some non structural damages like ceiling plaster peel off, partition wall hairline cracks and so on. Also the construction was happening 3-4 years ago, so if this were the case, then they wouldn't have to repair the pool deck prior to the construction that was going on.

Flexural induced punching failure is also a result of lack of flexural / top and bottom steel reinforcement in the slab. When the deck failed in punching, then initially it just feels as if it failed in pure punching shear and yes it was overstressed from a pure punching shear standpoint, but again it is based on the specified concrete capacity on plans. The punching shear stresses at these slabs is a result of two different components, one is pure gravity shear reaction at the column and other is the moments absorbed by the columns below. So the column at Grid KLM/13 were seeing the maximum stress because of these two different actions. Now the demands (just the weight of deck, pavers and sand) were over by a factor of 30% compared to the "Code calculated capacity". This code calculated capacity is also relatively conservative so that we can account for some construction differences, uncertainty in material strength and so on. So if I remove the factor of safety then the Demand to capacity ratio (DCR) 1.0 and on top of it, this is the peak stresses at the slab column joint when I combine flexural plus pure shear stress. Code doesn't allow a redistribution of these stresses as the redistribution of stress depends on what is the contribution of shear stress at slab column joint because of flexural transfer.

So we know that the capacity of slab punching realistically was okay to handle the daily load if there were enough flexural reinforcement (The reinforcement that is required for the slab to span between columns). If there is not enough top and bottom reinforcement (reinforcement along top / bottom face of slab) in the slab, then it will lead to moment redistribution. Code allows up to 10% of moment redistribution. What do I mean by this?

Now the slab span between grid K/13 and M/14.1 was 28.5' and the bottom reinforcement was not enough to handle the loads so it redistributes the stresses to the top reinforcement at column. And in general it is okay as reinforced concrete is good at that. But in this case, the top reinforcement at column was also barely enough to handle the loads even without this redistributed moments. So this leads to cracking / significant cracking at the slab column connection face. The magnitude of these cracks depends on the actual daily load carrying capacity and not just code calculated. So this flexural cracking because of lack of top reinforcement and its concentrated placement at top of column lead to a compromise in the punching shear capacity of slab. The top reinforcement was also compromised because of failed water proofing and as the cracks stay open for longer, the rebar corrosion also gets accelerated because rebar corrosion is also a time dependent factor. And since the slab was cracking significantly under its own weight, the crack duration can be justified as (almost) the age of the building.

The rebar corrosion leads to reinforcement delamination effects (not the same as coring because while coring concrete can get damaged in the core sample and does often separate from rebar if core is not big enough). With this delamination effects, you get further reduction in punching shear capacity. So, it was the lack of top flexural reinforcement coupled with high unbalanced moments at these column bays that has lead to a flexural crack at the slab column joint which in turn lead to a punching shear failure because the concrete lost its aggregate interlocking capacity and there by the strutting force. This can explain why the pool deck collapse and why it did take as long as 40 years.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Btw unbalanced moments are significant on columns that are supporting different length of slab bays. So in the image above, the slab span adjacent to the circled columns are 20' and 30'. This difference creates a significant moment transfer to the column below and a part of this moment transfer (around 40%) leads to additional shear stresses. So this bay seems to be the most critical bay that could very well have collapsed prior to anything else on pool deck.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (StructuralMadness (Structural)23 Aug 21 16:58)

By the way I finally figured out where to paste text into who you quote. Look for flashing cursor between outsides of square brackets to paste text in between

Thank You StructuralMadness for you excellent explanation. I think I understand most of what you said, or at least got the big picture?

I think it was IEGeezer a ways back in forum that mentioned this area was the area he felt was the most overstressed.

Edit: I assume the flexure in this area is due to auto traffic creating unbalanced moments, and then the rectangular columns to boot?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

So this bay seems to be the most critical bay that could very well have collapsed prior to anything else on pool deck.

Thank you very much for your detailed explanation. Because I am an analyst rather than an engineer, would you kindly clarify the boundaries of “this bay” as it relates to the space numbers and driving lanes in the garage?

The reason I am asking is because I have long wondered how Nicolas Vazquez and Gimena Accardi, who parked in the garage and got onto the elevator just as the deck collapsed at 1:15 AM, could have missed seeing the first slab that collapsed at 1:10 AM. Of course it depends in part on where they parked and the route they walked to the elevator. But if “this bay” was over a driving lane they didn’t drive on to get to their parking space, or over parking spaces off to the side of their field of vision, they could easily have failed to notice any broken concrete.

Thank you!

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (MaudSTL (Computer)23 Aug 21 21:11)

would you kindly clarify the boundaries of “this bay” as it relates to the space numbers and driving lanes in the garage?

#### Quote (2StructuralMadness (Structural)23 Aug 21 16:58)

Now the slab span between grid K/13 and M/14.1 was 28.5' and the bottom reinforcement was not enough to handle the loads so it redistributes the stresses to the top reinforcement at column.
+
first where is K/13 and M/14.1

and from StructuralMadness's image, what are the numbers

If I have misunderstood any of this, please correct me

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie)

Thanks for checking my understanding. That was close to how I interpreted it too, thinking that a bay was bounded by four columns instead of six. Depending on where the Vazquezes parked, they could have missed seeing it.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

2
I found an error in my spreadsheet calculating the weight of the planters. I am also correcting the height of planter #5A from 2 ft to 6 inches. That reduces the weight of the planters somewhat.

I am also proposing a cause of the failure of column K13.1 and therefore of the building. I am proposing fatigue failure due to the cyclical loads of the parking deck. Although the amplitude of the cyclical loads is small compared to the dead weight of the deck and planters, that may be enough to cause fatigue failure of column K13.1 because the column had a high load. Over 40 years there may have been hundreds of thousands of cycles as I believe this was the valet and visitor parking area. We cannot also forget Building Integrity's point about the deletion of a key beam that would have helped column K13.1.

I would have liked the cyclical loads to be larger to invoke fatigue failure, but fatigue failure checks the following points:

1. It would explain why the structure stood for 40 years and then, seemingly suddenly, collapsed.
2. It would explain the lack of a trigger.
3. It may explain the noises in the building as column K13.1 suffered slow-motion punching shear.
4. Other causes of failure seem less and less likely.
5. Only columns K11.1, K13.1 and K15 would seem to be subject to enough cyclical loads to suspect fatigue failure. Other columns may also have had high loads, but not subject to cyclical loads. The 24 in by 24 in columns may have been stout enough not to suffer this kind of failure.
6. I can't think of anything else. ;)

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (IEGeezer (Industrial)24 Aug 21 04:17)

Only columns K11.1, K13.1 and K15 would seem to be subject to enough cyclical loads to suspect fatigue failure.
I'm confused by your column nomenclature, Maybe I'm using the wrong sheet?

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (SFCharlie (Computer) (OP) 24 Aug 21 05:07 I'm confused by your column nomenclature, Maybe I'm using the wrong sheet?)

It looks like you are using Sheet S2 of 14 revised Jan 17, 1980 and titled Basement Level Dimensions. On the bottom left, I see a grid line marked 14.1 and one marked 15, shown as being about 12" apart. I don't see one marked 15.1. I used sheet S2C-1.0 from the Morabito documents dated 4/26/2021 and titled Level 1 Slab Reinforcement and Framing Plan. It was page 11 from the pdf. I uploaded it in my post above on 20 Aug 21 at 03:51.

The distances between grid lines marked in different blueprints don't match, but I haven't found a grid line marked 15.1. The west-most (i.e. bottom of the sheet) 12" by 16" column at the end of the valet and visitor parking area is offset to the north from grid line K. The vertical grid line for that column is not marked on that sheet, but it would be between I and K, but very close to K, so I am calling it K15. I had to measure very carefully, but I believe that column lines up with grid line 15, and not 14.1 (on the Morabito sheet). The sheet you are using shows 12" between 14.1 and 15. The Morabito sheet shows 8" between 14.1 and 15.

There is also an error on the left hand side of the Morabito sheet where 23' is indicated between grid lines 14a and 14.1, but the actual distance shown on the blueprint appears to be 16' 9". Trying to figure out the distances between columns is a nightmare. There are unexplained differences between blueprints. The whole thing is a dog's breakfast.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (IEGeezer)

The whole thing is a dog's breakfast

Perhaps, even if this collapse is never solved to everyone's 100% satisfaction, some edicts may emerge forcing existing building owners and regulation authorities to see that their paperwork is in order, and forcing re-surveys where they are not. This is not my field, but I am a little shocked that someone working on this building, pre-collapse even, would have such incomplete incorrect plans to work from.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I'm wondering if they thought of trying to recover dashcams from any of the vehicles in the above parking and the underground garage. Many dashcams have a "G-sensor" that will activate the camera when certain forces are applied to the vehicle. Even if some of the cars camera image was dark they might could see the time stamp of when it got activated (assuming the time settings were correct when it was setup).

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (IEGeezer (Industrial)24 Aug 21 06:53)

I don't see one marked 15.1.
My mistake, I don't see one either. I'm using the 1979 vs. 1980, 'cuase I'm lazy and I had it handy.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Jedidad (Computer)24 Aug 21 12:34)

I'm wondering if they thought of trying to recover dashcams from any of the vehicles
That has been wondered on this thread before. The point is Miami-Dade is still keeping everything very close to their chest, even though there is no chance of seeing a loved one recovered. I think that they think that they might be sued if something came out, but, at some point, they are going to be sued for destroying evidence by allowing it to perish.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (IEGeezer (Industrial)24 Aug 21 04:17)

2. It would explain the lack of a trigger.
I guess I wasn't seeing the forest for the trees, the building for the columns.
Yes, It seems to me the folk on this thread are coming to the conclusion that there was no trigger. To me, that is the scariest outcome, that a forty year old building just fell down...for a salt water environment and lack of proactive maintenance against corrosion...
Sloppy design, construction, inspection nor, regulatory oversight not excluded

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)
Updated power pointy do-da to reflect recent post re columns

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Without further video evidence, how are they going to determine the "sequence" of events? They are going to have to rely on survivor statements...what was seen, heard,, smelled and when.

Can they determine which column or slab fell first without visuals?

What other tools are available?

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

I don't have a subscription so I just read the top part like you, but it sounds like it's going to be talking about those sample cores drilled in the pool deck which didn't have any waterproofing in them. I think Building Integrity had a video about that linked earlier.

The K13.1 theory does have some merit to it, but to me it still seems like something internal around M9.1 failed first. We don't have any reports from people in the west side hearing things before the pool deck failure, whereas we do have that from 111 and 811. Everyone from the west side survived, so you'd expect them to have said something.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (MaudSTL (Computer)24 Aug 21 16:57)

For those with a WSJ subscription. Behind the Florida Condo Collapse: Rampant Corner-cutting. If anyone could share a copy, that’d be great.
If you don't already have a subscription, I find it worth it for the images (their photo editor has an excellent eye!) and the graphic animations Behind the Florida Condo Collapse: Rampant Corner-cutting.
I have included some quotes from the text as an attachment.

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Optical98 (Computer)24 Aug 21 18:55)

Without further video evidence, how are they going to determine the "sequence" of events?
... depends on who they is...
NIST had documented every step to the deconstruction of the aftermath with video, drone, and photography.
They have requested that everyone send any video to their web storage.
But we only get to see what they want us to see when they want us to see it, which will be after they have decided what happened, and will probably only support their version of the story

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Red Corona (Computer)24 Aug 21 19:06)

so I just read the top part...

...to me it still seems like something internal around M9.1 failed first
For more from the text see the attachment above.
M9.1 Located:

SF Charlie
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### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

My background is in commercial property mgmt, and resort mgmt on the west coast of Florida. I've also served on several boards and HOAs (houses not condos). I'm assuming the "they" would be Forensic Engineers with some other specialists sprinkled in. But yeah, without more info/evidence, I think this thread has dissected and evaluated as much as We can. Hopefully there will be further drops or leaks of info. Once the courts take over, they might be able to enforce more disclosure.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Optical98)

Without further video evidence, how are they going to determine the "sequence" of events? They are going to have to rely on survivor statements...what was seen, heard,, smelled and when.

Can they determine which column or slab fell first without visuals?

What other tools are available?

Thankfully they should be able to do a complete 3D rendering of everything found in the rubble exactly where it laid. There's enough drone footage and geo/laser tracking for them to easily be able to do that for much of the pile. Paired with destructive and non-destructive testing, they'll be able to get an idea of the strengths of everything in place. Scars on building materials will also likely be closely examined. You can usually tell new from old damage, impact vs shear, etc.

They'll be able to, for the most part, put the broken pieces back together. A fine tuned theory of the sequence and causes, but no real determinate answer is what we'll see, I feel.

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

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Demented (Industrial)24 Aug 21 22:46)

but no real determinate answer is what we'll see
I think a water to sand ratio similar to this Demented Image Find........

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (All About Da Money)

I think a water to sand ratio similar to this Demented Image Find........ponder
Oh we'll definitely get answers to that craziness with this crew. We'll learn about the rebar placement too I hope.

Again, this isn't Champlain Towers South, but still an ocean front condo, same PE stamp, same contractor, same crew, same inspection processes, etc etc. The photos of CTS are like the anti-corrosion coating.

*shrugs*
It's not like work of this high of quality was done on structural beams, the pool deck/parking garage ceiling, columns, or balconies/interior slab...

Water weight on that deck is gunna be so hard to prove. It's been months and it still hasn't rained as much as it did that month, and week in particular.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (Demented (Industrial)24 Aug 21 23:05 It's not like work of this high of quality was done on structural beams, the pool deck/parking garage ceiling, columns, or balconies/interior slab...)

I just watched this video by Building Integrity about "delamination" leading to the pencil head columns observed after the punching shear. He also pointed out how the cores were fractured.

How prevalent were concrete pumpers in 1980s Miami? When you are mixing on site, you may run out of time doing a large slab. In that case, did they pour the bottom half first and then come back the next day to finish the pour? Could that have led to "delamination?" Just a thought.

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

Yes, I believe there were instances of that.

The 1992-1997 and 2003-2009 (this was a long project with firm/contractor changes) concrete renovation to the pool deck is a lot of the major delamination we saw. Large portions, especially under and around planters, had full or partial depth repair work. There was about 14,000sqft total of repair work done to the top and bottom of the pool deck/parking roof slab. This is also where the failures in waterproofing and rebar placement seem to come from, rather than the initial construction. At least in regards to initial images that sparked the "where's the rebar" question in the first place.

Edit:

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

#### Quote (When you are mixing on site, you may run out of time doing a large slab. In that case, did they pour the bottom half first and then come back the next day to finish the pour? Could that have led to "delamination?")

It has been mentioned earlier that some contractors placed slab pours to the level of the bottom of the upper reinforcing and stopped there to lay the upper reinforcing on the concrete and avoid the use of high chairs. This would require a delay for the slab to set for foot traffic and to support the reinforcing.
The proper casting of a concrete member - beam, column, slab, footing, or wall is monolithic - one casting with reconsolidation between the layers of placement - or through a properly prepared cold joint.
Had I caught a contractor leaving an as placed joint surface in concrete he would have been sandblasting the entire surface to remove the interface surface sufficient to expose aggregates solidly embedded in the prior pour. That is a bit expensive.
On one project the contractor did not place the temperature reinforcing in a topping slab which was placed over precast tees. The flanges of the tees had been intentionally roughened just like DOT girders and were correctly prepared for a topping slab placement. The contractor should have called for an inspection. The remaining pile of reinforcing was the clue. He was directed to place the reinforcing, clean the slab, and coat the surface with epoxy. The reinforcing was temperature reinforcing - not the principal reinforcing providing strength for floor support, as the reinforcing of slabs at CTS was.
Cold joints were a problem at FIU. What is with the Florida contractors?
The concrete is/was likely mixed in a batching plant and trucked to the site. It might have been pumped or perhaps hoisted in buckets to the elevation being placed if there were a crane on the site. The handling of concrete, even in the 1980s, was clearly defined in the codes and industry practice. Batch times, number of turns of the drum on the truck, slump, added water - all are supposed to be controlled. Mixes are and were designed and load tags provided with reference to specific approved mixes, and the concrete sampled for slump and compressive strength. And it remains a problem today.
Reinforced concrete is the most structurally important product in most structures that is actually created on the job. Under less than factory controlled conditions - like rain, temperature, and other factors. But on the job it becomes just hard work, with a deadline only an hour away if you want to finish it correctly.
Thanks,

what a disaster,

### RE: Miami Beach, Champlain Towers South apartment building collapse, Part 11

(OP)

#### Quote (Jacob Henry (Industrial)3 Sep 21 06:49)

We are over on part 12. If this is just an ad, it might be removed.
Please let us know why you thought to post this link over on part 12 to help us understand why you suggested it, Thanks

SF Charlie
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