Miami Beach, Champlain Towers South apartment building collapse
Miami Beach, Champlain Towers South apartment building collapse
(OP)
Partial collapse of 12 storey apartment building in Miami Beach:
https://www.google.com.au/amp/s/www.dailymail.co.u...
Was built in 1981. Not much information as yet.
Building profile:
https://www.miamiresidence.com/surfside/champlain-...
https://www.google.com.au/amp/s/www.dailymail.co.u...
Was built in 1981. Not much information as yet.
Building profile:
https://www.miamiresidence.com/surfside/champlain-...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
It seems like a stretch to relate the two, but could it be ruled out as a cause?
Can someone with local knowledge give an idea of the seismicity of that area and whether a M3.9 earthquake would be significant compared to what it would (should) have been designed for in 1981?
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
I can’t see the military exercise being the culprit. If I were doing the investigation, I would think corrosion first. We will have to see as it plays out.
Prayers to anyone trapped in the rubble or injured in this.
RE: Miami Beach, Champlain Towers South apartment building collapse
Looks like panel construction - echoes of ronan point maybe?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Does anyone if this building was concrete or steal framed? Or know any specifics?
RE: Miami Beach, Champlain Towers South apartment building collapse
My glass has a v/c ratio of 0.5
Maybe the tyranny of Murphy is the penalty for hubris. - http://xkcd.com/319/
RE: Miami Beach, Champlain Towers South apartment building collapse
Overloading leading to progressive collapse?
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://twitter.com/wsvn/status/140805404680880537...
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
April 13, 2021 Image from Nearmaps
RE: Miami Beach, Champlain Towers South apartment building collapse
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://twitter.com/wsvn/status/1408054046808805379
RE: Miami Beach, Champlain Towers South apartment building collapse
I can't see a re-roof causing this. From the video it looks like failure initiated at the base. It would take an awful lot of materials to add enough load to a column to fail it.
Being so close to the Atlantic it could be some sort of long term corrosion.
Or something nefarious in the parking garage.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
How do the Search and Rescue crews evaluate safety during operations? Are there steps they can take to rate risk in entering and searching partially collapsed structures, and what would those be?
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Not me, but my boss volunteered someyears back to be an on-call volunteer structural engineer for fire departments. He would train with them occasionally for building collapses, partial or full, etc. and basically he'd be directed to inform them if they could demolish this wall, or this steel section etc. Where to put up temporary shoring if needed, etc. The risk assessment portion however is valid, and he explained some law (this is hearsay, so im not sure how true this is) that carves out an exception for structural engineering consulting during ongoing rescue operations.
RE: Miami Beach, Champlain Towers South apartment building collapse
This is probably far more info than you ever wanted, but here is one of the manuals for this role: http://www.disasterengineer.org/LinkClick.aspx?fil...
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
A few years back I worked on a mid-rise condo of the same era and roughly the same height. It had a very scary punching shear failure that was slow enough for residents to notice, report it that day, and for contractors to show up and install shoring posts immediately. Long story short, after a lot of investigation the columns of the condo portion didnt line up with the parking garage below so the original designers put transfer beams between the parking garage portion and the condo portion. The contractor did not put the specified shear reinforcement(and the concrete material breaks were quite low)at the transfer beams and it took 30+ years for a load case for the failure to show.
This is a complete speculation on my part, but it looks like theres a below grade parking garage here and I wonder if the column layout matches the framing above. You can see in the images the columns of the garage have clearly punched through what appears to be the 1st floor slab.
RE: Miami Beach, Champlain Towers South apartment building collapse
I may or may not have been involved in the construction...
guardiancenters.com/
RE: Miami Beach, Champlain Towers South apartment building collapse
Tragic, sickening to say the least.
RE: Miami Beach, Champlain Towers South apartment building collapse
If I had to guess I'd say this was a foundation failure due to subsurface karst topography. Stormwater management in Miami Dade SFWMD is usually done (or at least as of the mid 2000s) with infiltration pipes and baffles into the sandy subsurface aquifer. If the pH of the runoff is low enough, and that dropped the overall pH of the aquifer, it could have dissolved a layer of subsurface limestone and created an underground cave. When karst fails it's a dramatic thing that happens quickly, and that's about all I can think of for this one. The karst theory would fit spinspecdrt's photos too.
Typically SFWMD and the other water management districts prohibit water quality treatment through infiltration in known karst areas, and I don't know if Miami is a highly karst zone or not. I only did one project there, and we did infiltration in our storm sewer network out in the parking lot for it. It was relatively straight forward and we never did any investigations about karst.
I've done a project recently in Nashville where they required us to do infiltration measures for stormwater management even though we vociferously fought them on it because we knew we were on karst. I fear some failures similar to this may be in Nashville's future, whether this one was karst related or not.
edit: Ricky's post above is a great guess too.
edit2: some great rebuttals to this idea are below and I agree it doesn't seem like a karst related thing based on further info in the thread. Disregard, but I'm leaving it up for posterity.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
http://fcit.usf.edu/florida/maps/pages/11100/f1116...
I'm wondering about possible impact damage from a vehicle hitting a column in the parking garage.
I also remember staying at a similar condo complex in the Florida panhandle a couple of years ago. There were enclosed storage rooms inside the ground level parking garage where people could stash their beach chairs and pool toys. Inside those rooms was not climate controlled so they were incredibly damp. Anything left in there rusted quickly along with the doors, door frames, and anything else metal. So maybe there could be accelerated corrosion issues in exposed but mostly hidden areas of the parking garage?
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
The reports are coming in on the roof being worked on and there was a material lift for two weeks on that side of the building. I have evaluated at least two residential roof collapses because of improper staging of roof materials, albeit wood-framed residential, not a multi-story concrete building. But if 40 years of corrosion had affected the reinforcing, then you stage materials on top of that compromised roof slab, this type of failure is entirely possible. The roof repairs could have been to address an unmitigated roof leak, further exacerbating the situation.
I can not tell from the pictures if it is a flat slab with traditional reinforcement or post-tensioned, but we know that PT is vulnerable to catastrophic failure. Corrosion may have affected the ends at multiple floors and balconies. Once the roof slab started to fail it would pull inward on the walls, and the weight and dynamic force of that collapsing onto the upper floor could have caused a chain reaction failure, not that different than the World Trade Center collapses.
Like with most collapses, there are often multiple causes, and this could be one of those.
RE: Miami Beach, Champlain Towers South apartment building collapse
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Miami Beach, Champlain Towers South apartment building collapse
ETA - from the picture, there weren't drop panels or thickened slabs at the column locations.
RE: Miami Beach, Champlain Towers South apartment building collapse
More than 50 unaccounted for in deadly Surfside, Florida, building collapse, official says
https://www.cnn.com/2021/06/24/us/building-collaps...
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
I think in order for the roofing to have caused the collapse the weight of materials would need to buckle a column (or fail a transfer beam). Sure seems like it'd take an awful lot of load since it's 8 stories+.
RE: Miami Beach, Champlain Towers South apartment building collapse
When you consider that this collapse occurred at 1:30AM, if this apartment building was close to being fully occupied, that might be a very conservative estimate.
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
Link
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
‘The building was in OK shape.’ The upscale condo near Miami Beach still collapsed
https://www.miamiherald.com/news/local/community/m...
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
https://engineervsheep.com
RE: Miami Beach, Champlain Towers South apartment building collapse
Robert Hale, PE, SE
RE: Miami Beach, Champlain Towers South apartment building collapse
This is a pretty interesting tool to see the extents of the collapse.
RE: Miami Beach, Champlain Towers South apartment building collapse
Link
RE: Miami Beach, Champlain Towers South apartment building collapse
Search & rescue pics:
https://www.miamiherald.com/latest-news/jdzgc4/pic...
https://www.miamiherald.com/latest-news/tvr4b7/pic...
https://static01.nyt.com/images/2021/06/24/us/24mi...
https://i.cbc.ca/1.6078788.1624557189!/fileImage/h...
https://s.yimg.com/ny/api/res/1.2/qJfAx9QVjbb2fQAp...
Video:
https://www.miamiherald.com/news/local/community/m...
https://www.nbcnews.com/now/video/miami-mayor-mass...
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
Also, even though a collapse like this is the worst case event that TFs train for, it is not something that many teams or engineers have ever worked and I'd think that the mobilization of teams and cranes and other logistics would take 24 hrs or more. This seem unacceptable on the surface however many teams do not have the support they need to be on continual standby and deploy within 4 hrs for an event like this.
Most of you already know but I will say that a pancake collapse like this is the worst possible scenario for survivors as there are so few voids and refuge spaces. Rescue will be slow and dangerous and will be frustrating to observers. It really makes your mind start to work in overdrive trying to conceive a system or technology to rapidly clear a debris field like this to reach survivors but the reality is that it is an unknown and unstable and unconsolidated mass which will be removed one piece at a time, and on that last point I am exaggerating less than I wish.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://i.dailymail.co.uk/1s/2021/06/24/14/4462478...
RE: Miami Beach, Champlain Towers South apartment building collapse
Some good (can you say anything about an event this awful can be good?) video and before / after comparison.
RE: Miami Beach, Champlain Towers South apartment building collapse
seems like this could be a failure mode if water intrusion was occurring at every balcony
https://www.foxbusiness.com/lifestyle/miami-buildi...
RE: Miami Beach, Champlain Towers South apartment building collapse
Those lines appear to be the tear lines where the bottom steel has ripped out of the concrete soffit. You can see those tear lines extend into the support wall.
RE: Miami Beach, Champlain Towers South apartment building collapse
I did a detailed critique on the Engineering report for the Algo Mall... report was terrible, and apparently written by a PhD dude...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Politicians like to panic, they need activity. It is their substitute for achievement.
RE: Miami Beach, Champlain Towers South apartment building collapse
I would have expected the normal ~30 degree pyramid shape still attached to the column, unless this was lost among all the damage and debris?
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Construction PE (KY)
Bridge Rehab, Coatings, Structural Repair
RE: Miami Beach, Champlain Towers South apartment building collapse
Wow - my thoughts are with all those affected by this. Truly horrifying.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.dailymail.co.uk/news/article-9722547/C...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Headline: "Collapsed Miami beach condo tower hadn't been certified since 1981 when it was built and has been 'sinking into the ground since the NINETIES' "
Article: " Miami Dade building code dictates that buildings have to be re-certified every 40 years so the building was due to be recertified for the first time this year. "
Still a tabloid.
RE: Miami Beach, Champlain Towers South apartment building collapse
You can’t assume that a structure standing for decades means that it’s structurally adequate. Inadequate structures often survive for significant amounts of time.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
The rescuers have about 100 hours to get the trapped people out. There might be some space between the pancaked floors that will allow them to survive. Really hope so.
ex USAR Task Force 7 Sacramento. Structural Specialist.
RE: Miami Beach, Champlain Towers South apartment building collapse
The weekend after the Loma Prieta Earthquake a team from our company was working the Oakland area. Signed in, at one Red Tagged building 'transient hotel', walked up 7 flights of stairs to a landing where we could step out onto a low roof. Standing there looking up, there was floor after floor of giant 'X' patterned shear crack between the windows. The lowest 'x' shear crack, I could put my arm through. I reached in and grabbed a hunk of concrete, with my gloved hand and squeezed it, until it crumbled in my hand. There was no modulus left, completely friable. I can't say whether it was carbonation or if the sand used at the time was just not washed well enough. The building had smooth rebar, so early 1900s. Could not believe there were people sitting on the mattresses on the floor in a couple units, wondering what they should do.
I am a bit puzzled by the report about the building settling 2mm a year. One news station state the Professor indicated the land was settling. That has been my impression since looking at Sweetwater across from the FIU Pedestrian Bridge Collapse. There is an ongoing effort to remediate flooding in Sweetwater. All the old USACE work has reached capacity with runoff from surface streets. The problem stated was that the land was settling and also the Okefenokee Swamp watershed was getting larger. Bigger and more pumps were needed. Sweetwater is a good ways inland.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Related: has anyone else noticed the LACK of structural engineers weighing in among the media outlets? I admit I have not viewed any of this on television today, so perhaps I missed one or two, but I'm reading article after article with 'expert opinions' from
- local architects 'who've never seen this in 30 years of living and doing business in S. Florida',
- some owner of a local home builder (very applicable to mid/high-rise concrete construction over underground parking built along the coast),
- an attorney who represented someone on a trip & fall case in the building who is 'very familiar with that building'...
...WHERE are the SEs and PEs of Florida?? I hate to say it, but this is the kind of event where the public is thirsting for our knowledge and they don't even know it...talk about an opportunity to elevate the profession. Perhaps we as a field need to have public speaking and media training to draw us away from our desks and in front of the cameras in cases like these. Meanwhile, I have to get back to my condition assessment report, so someone else please do it.RE: Miami Beach, Champlain Towers South apartment building collapse
Or perhaps the structural engineers consider that it is irresponsible to wildly speculate, as some of those other 'experts' are doing. The press will tag an expert label on anyone who has ever held a hammer.
RE: Miami Beach, Champlain Towers South apartment building collapse
1. @FoxSE14 - Hopefully local PE's are staying cautious and don't want to speculate. Although I did hear an FIU professor answer a few (not so great) questions of a local reporter.
2. There was one level of underground parking - this is actually not uncommon in this area - land is way too valuable to waste any, esp. when above ground gives you ocean view and there are height restrictions of the oceanside properties.
3. My guess would be that the columns holding the ground floor (the lobby/pool deck level) did not coincide 100% with the columns above.
4. Collapse looked, as others have pointed out, in the center of the building. (which ironically appears to be slightly shorter than the oceanside end)
5. As others have stated above: could be a 'simple' as a column being taken down in the parking, maybe the overloading of materials happened at the lobby/pool deck area rather than at the roof? I've heard random statements about a possible crane aiding with the ongoing roof work, but have not seen any sign of one or that being verified. It would be sad to find out the failure of ONE column would cause this, so maybe a transfer beam or punching shear failure would make more sense? Although with little redundancy if the floors above don't match the basement columns then this def could be a weak point.
It's hard to imagine a tragedy like this happening with no warning signs. Expecting the typical "stacking of mistakes" result.
God help the people still trapped and guide the responders to find them ASAP.
To whoever asked above why there is no recovery - there is! Miami Dade PD tweeted out a video showing them working through the flooded basement - this is no easy task to try to find Survivors and not compromise the debris pile
https://twitter.com/MiamiDadeFire/status/140817768...
You can find the pictometry historical aerial views for free on the Miami Dade Property Appraiser site
-- sorry for long post, this has def hit way to close to home
RE: Miami Beach, Champlain Towers South apartment building collapse
I got about 5 phone calls this morning from friends and family asking my opinion on the collapse. I have no idea what happened, but I loved having the discussion with them.
As long as those engineers talking to the public state that their opinions are speculation, it would be better for our profession overall.
S&T
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.zillow.com/homedetails/8777-Collins-Av...?
RE: Miami Beach, Champlain Towers South apartment building collapse
The only thing that I can plausibly imagine is that a major transfer beam failed, which overloaded adjacent columns -- leading to a cascading failure.
In this region moments from seismic events are not an issue, our biggest challenge is protecting the buildings envelope from wind loading, especially negative pressure.
RE: Miami Beach, Champlain Towers South apartment building collapse
A truly horrific event.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
So sad and tragic that I can't wrap my head around how a failure like this happens..
This picture just makes my jaw drop and my heart sink: https://i.dailymail.co.uk/1s/2021/06/24/14/4462478...
RE: Miami Beach, Champlain Towers South apartment building collapse
Someone has security video from inside their apartment just before collapse.
RE: Miami Beach, Champlain Towers South apartment building collapse
It seems like if any sort of forensics is going to be done the cleanup and recovery will have to be done in a very controlled fashion. Will they have to bring that part of the building down before they can start to clean all of this up?
Where does this spontaneous (for the moment) collapse disaster rank in the US? And worldwide?
Tragic.
RE: Miami Beach, Champlain Towers South apartment building collapse
I really am doubtful of subsidence, simply because a mat foundation with piers is not very common on oceanfront construction at that NGVD or NAVD elevation. The sheet piles for the underground parking and the associated dewatering is tough enough,
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.nydailynews.com/news/national/ny-deadl...
RE: Miami Beach, Champlain Towers South apartment building collapse
One of the residents claims he noticed pool patio pavers cracking during the construction of the adjacent high rise building.
Source: https://www.pbs.org/newshour/nation/wing-of-miami-...
RE: Miami Beach, Champlain Towers South apartment building collapse
Ronan Point Apartment Tower
Alfred P. Murrah Federal Building - ref. Oklahoma City Bombing
In this case, I don't think it is wild speculation to hypothesize that long term settlement overstressed and led to the failure of a 2-way floor slab to column connection. This doubled the bracing length of this column which then exceeded its axial capacity and failed suddenly under buckling. The other hypothesis would be a failure at a column to transfer beam connection.
Questions to investigate - what is the detailing of the 2 way slab to column connection? Photos only evidence top horizontal rebar
What was the geometry of the parking grid columns to apartment grid columns?
Did the building really settle 3" and was that settlement discrete or overall?
I think its important to recognize that the reason for our attention on this disaster is due mostly to the lessons that we, as engineers, learn from failures. A failure that occurs suddenly 40 years after a building's construction, especially if it was properly detailed and built, is something to be identified and corrected for the sake of the rest of our buildings' catalog.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://i.guim.co.uk/img/media/cff046f016f8d329b3d...
and
https://i.guim.co.uk/img/media/1bf3fd047ad86fc5c0e...
show damage to the walls about half way up one remaining façade.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Live load considerations?
Shoreline rebar deterioration and or inadequate cover from the onset.
Such a catastrophe!
f-d
ípapß gordo ainÆt no madre flaca!
RE: Miami Beach, Champlain Towers South apartment building collapse
As I just learned (and shared the link above), the instigating event behind Miami's 40 year recertification process was the collapse of the Miami DEA building in 1974, which was 40 years old at the time. The Miami-Dade engineer behind the effort saw the particular vulnerabilities of aging structures in the area, and was determined to create a process that would help prevent future collapses.
RE: Miami Beach, Champlain Towers South apartment building collapse
Long-term settlement caused cracks in concrete, allowing saltwater access to the reinforcing rebar, and increased stresses on connections.
Vibration from nearby construction (and general use) worsened fatigue.
Roof work increased live load.
One of the basement connections eventually failed, and the whole thing pancaked.
Obviously there are lots of open questions. Was the settlement due to sea-level rise unaccounted for at the time of construction? What was the immediate cause of the collapse? Are any of the WAGs even true, or was it something else like a sinkhole? What code or enforcement changes could prevent this? How many other buildings in the area are at similar risk?
RE: Miami Beach, Champlain Towers South apartment building collapse
I wondering if there is a gradual effect a bit like the increase in "average" passenger weight that they use for aircraft has needed to be updated as the population got bigger and heavier??
A little of googling finds the average weight of a car in the 1980s was about 3,000 lbs and is now over 4,000 lbs.
Given the residents of the block are probably in the higher percentile earning group are likely to have bigger cars than the general population??
Could you be talking double the weight compared to what was assumed in 1980?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Miami Beach, Champlain Towers South apartment building collapse
Dan - Owner
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RE: Miami Beach, Champlain Towers South apartment building collapse
Before IBC 2006 I believe parking garages were 50 psf. Now they are 40 psf.
Average car length is like 14-15 feet x 6' wide. Cars this size weight less than 3000 pounds. 40 psf gets you 3360 that's assuming cars are packed like sardines. With the drive aisles spaces between cars, etc. 40 psf is pretty conservative in most parking garages.
RC
RE: Miami Beach, Champlain Towers South apartment building collapse
Maybe they should make it every 30 years?
Good Luck,
Latexman
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
f-d
ípapß gordo ainÆt no madre flaca!
RE: Miami Beach, Champlain Towers South apartment building collapse
a disaster of this magnitude. where does the investigation begins to resolve the cause?
since this is a high rise building were to start.
what test would be required.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.newsweek.com/water-underneath-surfside...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
This type of catastrophe appears to be from overall stability failure. Buildings just don't collapse suddenly like this even with some local structural failure.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://profilemiamire.com/miamirealestate/2017/9/...
RE: Miami Beach, Champlain Towers South apartment building collapse
If Miami wasn't enforcing this requirement, I can see the lawyers lining up at their door... criminal negligence, anyone?
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
poorly executedillegal demolition effort.https://www.eng-tips.com/viewthread.cfm?qid=442327
RE: Miami Beach, Champlain Towers South apartment building collapse
https://sw-ke.facebook.com/CBS12News/videos/teri5a...
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.google.com/maps/@25.8732046,-80.121095...
RE: Miami Beach, Champlain Towers South apartment building collapse
I played with the street view you linked to, and you can definitely see that several of the lower balconies were in poor repair on their undersides:
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.google.com/maps/@25.8732099,-80.120874...
https://www.google.com/maps/@25.8732046,-80.121095...
But would that explain it collapsing from below?
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.newsweek.com/2015-complaints-collapsed...
RE: Miami Beach, Champlain Towers South apartment building collapse
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
2019: construction of building on adjacent lot
2021: noticeable damage at roof and balconies
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
In big accidents like this, it's rarely 1 single item that causes the failure; there are usually many contributing factors that all come together in the wrong way.
I would think the sinkhole aspect will be validated or thrown out rapidly; but all the other possible causes will probably take months to figure out.
After the Florida International Pedestrian Bridge, this is a 2nd large failure in Florida. I think that will motivate the public; who will then motivate the politicians on some substantial engineering changes. I would be surprised if there were not national implications.
We will be studying this collapse in college classes forever, just like the Hyatt Regency walkway collapse in the early 1980's.
I feel so bad for the families in that building.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Here is some additional information, including name of firm doing the 40-year certification in link below.
Someone asked above if the enforce the certification, they do, but just like the rest of sad state of our profession, a lot of people don't want to pay for what i think is a big liability and responsibility task.
https://www.local10.com/news/local/2021/06/25/meet...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Furthermore, initial reports confused 135 and 136 units, it appears at some point the "Penthouse A" was added (possibly during construction) as the flyer from 1980 for the building only states 135 units and 12 floors. The penthouse is the 13th floor and 136th unit - it was recently sold and the listing noted marble floors. The penthouse and HVAC unit appear to share a column at the SE corner of the HVAC platform that seems to be the source of the collapse.
I wonder if they placed any additional equipment on or near the HVAC platform prior to collapse and if the building was structurally designed for the penthouse. It is also possible the platform itself failed if it was not designed for the new equipment - it does not look like they replaced or strengthened the platform when the new equipment was installed. To me, this does not look like a sinkhole but a progressive collapse from the roof for the first portion that collapsed as it did not tip over, followed by a failure of a low level (possibly garage) column due to debris causing the second collapse where the remaining building essentially tipped over on top of the first collapse.
Note: I have not been able to access assessor or permit info for this building on the town or county websites, it seems to be blocked - which is pretty unusual.
-W
2019 aerial (old equipment):
2020 aerial (new LARGER equipment):
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Whatever the failure mechanism was, it started local. Why couldn't those forces redistribute?
In the Oklahoma City bombing, half the building was blown off and it did not pancake. The same is true of the World Trade Center bombing in the mid-nineties. Both buildings took massive blows without total global failure.
RE: Miami Beach, Champlain Towers South apartment building collapse
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
hokie66: No PT from my observations. I am seeing bottom rebar that has 'unzipped' from the slab soffit.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
I don't think these are PT tendons.
No appearance of drape. No anchorages appear to have been ripped out. No one - not even in the 'evid-80's' - placed single PT tendons at 12" centers - always multiples bunched in flat groups at greater spacings.
Looks like deformations on the fallen/hanging 'bars' - so possibly rebar (that has unzipped from the slab soffit)?
RE: Miami Beach, Champlain Towers South apartment building collapse
I re-watched the video and it doesn’t look like a “pancake” type of progressive collapse. There’s a loss of support of one side the building which then radiates through the rest.
Regardless of what caused the loss of support, the structure should have been able to redistribute that load.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
I see what you are saying. The insurers will say it was a bad design from day one, so how can they be responsible.
RE: Miami Beach, Champlain Towers South apartment building collapse
Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
But I agree with someone else above that the deformed bars look uncommonly clean to have been ripped out of the slab.
RE: Miami Beach, Champlain Towers South apartment building collapse
There was a building collapse further up the east coast of Florida long ago (early '70s?) where the chairs were too tall. The building pancaked during construction as an upper floor was being poured, killing several workers. As I recall, the incorrect height of the chairs was found to be a major factor in the failure, so proper placement of the rebar is obviously critical.
Would having the rebar too close to the bottom surface seriously weaken the slab? Or is this something that would show up after the failure that didn't contribute to the failure?
RE: Miami Beach, Champlain Towers South apartment building collapse
On this building if you look at the roof level and the floor below that (11th or 12th), the rebar appears to have also unzipped like the photo posted at the ground level (photo above):
I think the bottom cover to the bottom rebar was very small - with possible badly consolidated concrete surrounding bottom of rebar and therefore little bond ==> hence ease of unzipping.
The potential unzipping of rebar may have commenced at a construction joint - the rebar was developed into the slab portion that collapsed, and as the slab/s fell it ripped/zipped the reduced-cover rebar in the span that remained. Notice how 'clean' the exposed slab edge at the roof level.
Also, notice the 3" vertical slices @ 10" c/c (?) to the dry-wall under the roof slab soffit - rebar 'cut' the top of the partition wall.
RE: Miami Beach, Champlain Towers South apartment building collapse
one or more concrete columns at the garage level the plausible reason is salt weathering of concrete. Concrete spalling due to the corrosion of rebars
should be also considered, but this will be rather unlikely, as the core of column shall be unaffected, and the local loss of section would create a "Freyssinet
hinge" contained by the vertical rebars and stirrups, or the remaining parts of these. The following is an interesting and likely related quote from a research paper
"Damage of Concrete and Reinforcement of Reinforced-Concrete Foundations Caused by Environmental Effects" published by Procedia Engineering as open access article:
"Salt weathering"
This occurs in concrete due to the capillary rise of water rich in slats through the soil and foundation structure. It
is prevalent in the areas with the considerable concentration of chlorides in the soil, ground water and atmosphere,
which is mostly the case in the coastal areas of the warm seas or in the structures where defrosting salt is often used
414 Zoran Bonić et al. / Procedia Engineering 117 ( 2015 ) 411 – 418
(road structures). Nevertheless, the mechanism of the crystallization process is similar to frost action. Namely, the
pressure caused by crystallization brings about the onset of cracks in the pore walls and afterwards the cracks, due to
crystallization in them grow bigger. This process, in presence of new amounts of water rich in salts, continues,
causing massive concrete degradation. The basis of this process is the reaction of calcium chloride (CaCl2) and
sodium chloride (NaCl) which causes changes in the Portland cement and causes generation of calcium hydroxide
(Ca(OH)2) [5].
This kind of concrete degradation, known also as chloride aggression, is particularly prominent in those cases
when the structures are positioned near the warm seas, in the conditions of high concentration of chlorides in the sea
water, soil and air. Warmer climate, in comparison to the areas with the continental and temperate continental
climate enhance salt weathering. In addition, high temperatures have an additional detrimental effect because
concretes, for the reasons of better workability are made with a high water/cement ratio which causes, in the
concrete hydration process, an increase in the concrete paste porosity, which facilitates capillary rise of chloride
saturated water after concrete hardening. The higher temperatures are the cause of the faster initial hydration of
cement which leads to the increased porosity of concrete and facilitates capillary rise and crystallization of chlorine
ions"
Full article is attached as pdf file.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.townofsurfsidefl.gov/docs/default-sour...
8777 COLLINS AVE - Structural Field Survey Report:
https://www.townofsurfsidefl.gov/docs/default-sour...
8777 COLLINS AVE - Unverified Inspection Report:
https://www.townofsurfsidefl.gov/docs/default-sour...
All Records:
https://townofsurfsidefl.gov/departments-services/...
RE: Miami Beach, Champlain Towers South apartment building collapse
Not looked at the drawings yet but I suspect you'll find why that's the case....
Those bars ripping out of the underside of the slab is quite extraordinary, never ever seen that previously on any other structural collapse. Usually you see fractured bars not delamination areas like this. Very odd.
https://engineervsheep.com
RE: Miami Beach, Champlain Towers South apartment building collapse
of the foundations - the beams listed suggest that some of the columns were supported by them, and that's adding to the list of potential mode of failure. It's also worth of noting that the level of the parking garage is below the sea level, so it's making the columns bases located in the "splash" zone and subject to accelerated corrosion and salt weathering of concrete. Unfortunately all of this is not a subject of 40 years' certification investigation, as the most important are the roofs and AC units.
RE: Miami Beach, Champlain Towers South apartment building collapse
Link
RE: Miami Beach, Champlain Towers South apartment building collapse
9.5" thick RC flat plate at ground floor.
EDIT:
No obvious column transfer conditions to the ground floor levelSee post below.Typical floor dimensions and column layout to the collapsed area:
Basement dimensions and column layout to the collapsed area:
Very 'light' on structural walls for lateral in E-W direction!
3,000 psi concrete from Level 9 floor to roof level - oh, the 80's!!!
RE: Miami Beach, Champlain Towers South apartment building collapse
Link
RE: Miami Beach, Champlain Towers South apartment building collapse
Whilst drawing S-3 PILE CAP DETAIL PLAN appears to be missing (or out of order in the many documents) drawing S-11 has this note:
RE: Miami Beach, Champlain Towers South apartment building collapse
Typcal floor part framing:
Ground floor part framing:
RE: Miami Beach, Champlain Towers South apartment building collapse
Compare the photo and the layout, the area hatched in blue is not built.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://townofsurfsidefl.gov/departments-services/...
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.townofsurfsidefl.gov/docs/default-sour...
RE: Miami Beach, Champlain Towers South apartment building collapse
I am on my phone and it does not want to open such a large PDF
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Is there a garage underneath?
RE: Miami Beach, Champlain Towers South apartment building collapse
Yes, but not under pool itself. The small spa drained into the lower level? Columns to lower level can be seen on pool deck area.
See Ingenuity (Structural)26 Jun 21 02:3 for image taken from below the pool deck.
RE: Miami Beach, Champlain Towers South apartment building collapse
Beams BM33, BM34, and BM35 are in the attached beam schedule.
Stirrups in BM33 and BM34 look odd to me. Seems like the shear would be nearly constant on each side of the point load.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.keller-na.com/expertise/techniques/fra...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Foundation drawings shows PIF's (pressure injected footings). Then call out 14 x 14 precast driven to 50 tons (100 kips).
14x 14 precast are usually driven to 75 kips and I doubt that they would ever be used at 100 kips in South Florida.
Likely Franki or other PIF's at 100 kips. Franki's were being used in South Florida in that time period.
Videos show what appears to me as a failure that started at or near the bottom of the building.
Without speculating as to the cause, which would not be ethical as I am not involved, I would pursue the question of column failure at the
garage level as suggested by others in this forum. Photos show corrosion and indication of previous flooding of the garage which is accordance
with resident reports.
Was the concrete remediation started? Had garage columns been chipped to repair without multi floor shoring? Had past repairs to the columns been made?
Remediation plans call for no more than 1/4 of a damaged column be repaired at one time and call for shoring.
Mojojohn
RE: Miami Beach, Champlain Towers South apartment building collapse
It's actually pretty plausible that a patio slab failure could have been the initiating event here:
There is otherwise not a whole lot of reason why the collapsed portion of the building zone should have caused as large a portion of the patio to fail as it did. Water ingress through failed waterproofing in the patio area could have damaged rebar connecting columns to the slab leading to shear failure and a single initiating punch-through of a single column. Such a punch-through could overload neighboring columns with similar damage leading to a cascading collapse in the patio zone.
The suspended patio would now have very high tensile stresses in its rebar with the rebar acting like the cables in a suspension bridge. The rebar on the bottom (east-west oriented) seems to have torn out relatively easily, relieving those stresses and potentially saving the southwest corner of the structure and making the load be carried in the north-south oriented rebar.
The extreme tensile stresses in the north-south oriented rebar from the collapsing patio would mean that the patio level slab, instead of providing lateral stabilization to the columns in the portion of the building that failed first, would instead be destabilizing those columns.
From the perspective of the patio slab, the (relatively) stiff intact columns become stress concentrators for those tensile stresses. The columns under the building proper, probably bigger and better protected from water/corrosion than those under the patio, would be less likely to have punchout failures and more likely to transfer the tensile loads into the sides of the columns. Now we have highly loaded vertical columns with a significant sideload. It would only take one of these to buckle to initiate the major collapse. I am thinking of our undergraduate mechanics of materials lab where students put a rod in compression and then tap it from the side and it buckles instantly. With few internal walls, such a single column failure may have been enough to destabilize the larger structure.
RE: Miami Beach, Champlain Towers South apartment building collapse
The PFI call out on S3 is for 300 kips
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Page S-11 notes state 14 x 14 at 50 tons.
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
40 years may be too long a stretch... maybe 20 or 25 years would be more appropriate considering the 'corrosive' environment...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
The sensitivity of a punching shear mechanism is well-documented, with transfer of unbalanced moment at the slab-column joint component always requiring close consideration in addition to the direct two-way shear component. Eccentricities and misalignments in the concrete frame, whether subsurface settlement/subsidence-related or otherwise, only serve to magnify the system's sensitivity.
Just seems like a confluence of a lot of less than ideal attributes: subsurface element performance/displacement, a comparatively sensitive structural system (two-way flat plate, not to mention some big-time transfer girder elements down low), and an unforgiving coastline exposure.
RE: Miami Beach, Champlain Towers South apartment building collapse
Engineer Warned of ‘Major Structural Damage’ at Florida Condo Complex in 2018
https://dnyuz.com/2021/06/26/engineer-warned-of-ma...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
I can’t help but draw a parallel to the Hard Rock collapse in New Orleans, where a design flaw created a weak plane that inadvertently allowed a section of the building to collapse without dragging down the rest of the building.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.cnn.com/videos/us/2021/06/26/structura...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.dailymail.co.uk/news/article-9728053/M...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
"SURFSIDE, Fla. (AP) — The oceanfront condominium building that collapsed near Miami had “major structural damage” to a concrete structural slab below its pool deck that needed to be extensively repaired, according to a 2018 engineering report on the building.
The report was among a series of documents released by the city of Surfside as rescuers continued to dig Saturday through the rubble of the building in an effort to find any of the 159 people who remain unaccounted for after its collapse."
Anyone able to obtain a copy of this report?
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
I see from the drawings there is a transfer beam as well, I have not looked at the shear reinforcement in that area, but if the reinforcement is corroding in the below grade beam, but if the Vs value drops due to corrosion of the ties, that could be a source of concern as well.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.townofsurfsidefl.gov/docs/default-sour...
RE: Miami Beach, Champlain Towers South apartment building collapse
Thanks jrs... I have that one... apparently there is a report of far more serious damage that seems to have been missed/overlooked in the Morabito report.Maybe the're the same... I got the impression that the 'second' report was more comprehensive... I didn't get that from the Maratibo report.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Now for rant (I apologize)
The fact that column was not shored immediately, to study the cause of the distress makes me extremely frustrated. Buildings, do have problems but when a visible issue is not investigated for 3 years, someone needs to go to prison. The lack of accountability drives me nuts, for example.
1) I' am not a Electrical Engineer, but yet I know that the Switch Gears need to be greased and maintained.
2) I' am not Mechanical Engineer, but yet I know that cooling towers need to be cleaned.
3) I'am not a specialty engineer (elevators) but I know that the motors and cables need to be maintained.
There are many things that I personally am not qualified qualified to do, or in the case of the switch gear (too afraid to do) but yet it is pretty simple and inexpensive to find a qualified professional maintain the systems.
/
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Makes me sad. What an absolute tragedy (what happened and what will happen).
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
These condos are full of cheapskate board members who think they’re engineers. And the owners don’t understand that these coastal RC structures have usable lifespans. As they age, repairs (and special assessments) will get more frequent, until the building becomes uneconomical to repair and must be demolished. I predict that in the coming decades, you’ll see older units become essentially “free”, with astronomical fees to fund repairs.
RE: Miami Beach, Champlain Towers South apartment building collapse
Structural damage from what?! Good grief....
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://dnyuz.com/2021/06/26/engineer-warned-of-ma...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Perhaps the unzipping occurred at a very high velocity. The unzipping was secondary to the collapse, as corroded bar would not unzip like this.
RE: Miami Beach, Champlain Towers South apartment building collapse
Someone should investigate whether (in an attempt to appease today's multi-vehicle families) the parking structure was reconfigured from the original layout to pack more vehicles in, exceeding the original design's specs.
Even if it wasn't changed I have to believe the load on the parking deck was more than it was in 1981, despite some cars being lighter. The number of crossovers, SUVs, and pickups owned today cancels out any weight improvements in sedans and other small cars. And that doesn't even take into account electric cars, which are a lot heavier than their 1980's counterparts.
The timing of the collapse is interesting. Do bars still close at 1AM like they did when I lived down their in the 70's and 80's? As suggested earlier in this thread, it wouldn't be much of a stretch of the imagination to think that someone who had too much to drink mistook the accelerator for the brake pedal and plowed into a column, dropping the already weak deck above them and causing a cascading failure due to all the other problems this building had. Was there CCTV coverage of the garage and did the server survive? Regardless of what triggered the collapse, that would be some interesting footage indeed.
A column being taken out under the pool deck could explain the "sinking" that was reported just before the collapse. If it turns out it did start under the pool deck, it's criminal a part of the structure that has no bearing on the rest of the building could "tug" enough on the columns where the collapse occurred, causing them to snap in half and causing a catastrophic drop of the deck under that part of the building - and as has been speculated already - the lack of lateral support causing a cascade event of columns buckling.
I'm shocked by how easily the deck sheared from the columns and how cleanly the column rebar pulled out of the deck in the section where the building managed to remain standing. Those residents are extremely lucky - the only thing that saved them was the parking deck cleaving cleanly from itself, leaving the rest of the deck aloft to provide the necessary lateral bracing.
The piss-poor rebar placement is just as shocking. Perhaps someone thought because Florida doesn't have earthquakes the possibility of rebar unzipping from the bottom of the deck was highly unlikely? Perhaps even thinking the more concrete above the rebar made the rebar less likely to unzip from the top of the deck where it mostly mattered? I suppose the most likely reason for what we are seeing is a rushed construction schedule which prevented workers from properly positioning the rebar in the middle as it should be.
The building seemed top-heavy to me, especially from the slow twisting path the last section took during its fall. There's no excuse for that section to remain standing and then fall soon after. A building should be able to stand even if an entire row of columns is compromised. It's interesting the part that fell had a penthouse addition added after the initial design. It also doesn't help non-structural concrete block was used as sound and fireproofing. That's a lot of extra dead weight the structure had to carry.
And finally it's being revealed the building actually did have major structural issues that needed to be fixed, which only compounded all the issues (and possible issues) above. It is unfortunate it was procrastinated upon for 3 years until it was too late.
RE: Miami Beach, Champlain Towers South apartment building collapse
No, you can not! The structure doesn't have sufficient shear walls parallel to the numeric grid.
The design wind load for buildings located on the coastline is very high. Note, I'm not saying that is the cause of the collapse, but the drawing shows only two 8ft long shear walls to fend off a high-velocity hurricane zones wind pressure x the building area facing the ocean(150ft x 117ft)? You can't make this work.
RE: Miami Beach, Champlain Towers South apartment building collapse
Why are you calling me a troll?
What's that all about?
Dik mentioned that there was a report in 2018 that mentions 'structural damage'. As a Californian, I usually only hear of structural damage caused by seismic activity.
How do I reply with a quote? Maybe that's why @jrs87 is not clear on my question.
RE: Miami Beach, Champlain Towers South apartment building collapse
During my time in Central America I observed the following construction sequence many times.
1: Low slump is your enemy. Concrete was typically mixed with
almost novery high slump so as to be easy to place.(Corrected)2: Re-bar is often laid directly on the forms for elevated floor slabs.
The wet mix leaves the concrete very porous.
Moisture attacks the re-bar and corrodes it.
Iron oxide has more volume than the original iron, and the expansion due to corrosion blows the concrete from the re-bar.
A common sight in older buildings is a concrete ceiling with the re-bar grid exposed and rusty.
A friend of mine was having a new house built. The design called for a cantilevered shade deck over the entrance to the garage.
When the contractor started to remove the forms, the deck started to subside.He tied it back to a parapet wall with cables and turnbuckles.
I was asked to look at it. I remarked that an overhung deck would not be supported by rebar lying on the bottom form. The re-bar must be higher in the slab to be effective.
The owner talked to the engineer and reported back to me:
"The engineer says that the re-bar must be on the bottom to keep the concrete from falling."
Without close supervision, a crew with southern experience will tend to revert to the way that they were originally taught, which is also easier.
I would suggest that the lower the wages, the more supervision is needed and the more suspect will be the concrete quality and the correct placement of the re-bar.
My favorite for the all time worst re-bar placement was a narrow roadway up a side hill.
The roadway was graded and the re-bar was laid directly on the ground. Then construction traffic ran over the re-bar for a week or so.
Then the concrete was poured with no attempt to lift the re-bar up out of the dirt.
Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!
RE: Miami Beach, Champlain Towers South apartment building collapse
'No slump' concrete is very difficult to place - I think you mean high slump concrete - like 8"+ slump.
With today's admixture technology, concrete with a large slump can be ready-mixed without reduction in strength nor durability - not so much in the 'evil-80's'.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
There is a toolbar with icons in the editor that help you form your post. The term "Good grief..." in this neck of the woods is sometimes pejorative and mocking.
Hope, we are past this now with no worries and back to the subject.
P.S. Corrosion is form of energy like seismic activity. So corrosion plus gravity equals structural damage. Right?
RE: Miami Beach, Champlain Towers South apartment building collapse
Would be interesting to see if any of the damage/corrosion from the 2018 report affected any elements in that area.
This still just so hard to believe, I would expect more load redistrubtion and large displacements before full collapse on a RC structure (even if the engineering/construction is suspect).
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Miami FD communications
RE: Miami Beach, Champlain Towers South apartment building collapse
SF Charlie
Eng-Tips.com Forum Policies
RE: Miami Beach, Champlain Towers South apartment building collapse
Welcome to the board. Don't be disheartened. I was slammed hard for my very first post a few years ago. We have some spirited discussions here.
Brad Waybright
The more you know, the more you know you don't know.
RE: Miami Beach, Champlain Towers South apartment building collapse
Focus shifting to long term pool leak.https://www.dailymail.co.uk/news/article-9728053/M...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
To me, it looks as if they not only replaced the AC, but also changed it's location???
SF Charlie
Eng-Tips.com Forum Policies
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.townofsurfsidefl.gov/docs/default-sour...
Inspection done between 8/01 and 9/06/2018:
"2.Settlement: Good – no building settlement observed"
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://news.sky.com/story/miami-building-collapse...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Sounds like there was a column and slab failure in the basement with a few minutes of load redistribution before there wasn’t anywhere left for it to go.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.reddit.com/r/CatastrophicFailure/comme...
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
The three exposed columns where the parking slab fell (J12, J14, J15) are larger than necessary for architectural reasons below the second floor, likely why this portion of the building did not collapse.
The columns in the collapsed portion were at minimum dimension all the way down, hence they would be first to fail with deterioration, settling, etc.
ALL of the columns in the initial collapsed portion are Type C at the exterior and Type G at the interior.
These columns have quite a bit of rebar at the lowest levels 12 x #11 in 16 x 16 (Type C) and 10 x #11 in 14 x 18 (Type G.)
Both types near the maximum reinforcement ratio, once concrete spalling occurs they would theoretically be over code allowed ratio and need to be strengthened.
But, they weren't strengthened due to parking, to enlarge columns reduces parking space size or the space altogether, so the HOA technically wasn't allowed due to zoning laws.
In addition, they appear to have been overloaded. According to the plans provided, the columns were not designed for the penthouse addition.
The column schedule mislabels floor 12 as the penthouse.
The penthouse addition drawings show the penthouse at the roof level or floor 13 (the elevator to the penthouse from floor 12 does not appear to have been added, instead the corridor was extended to the main elevators.)
The area under this corridor collapsed first.
Finally, the recertification documents note the structural steel supporting the HVAC system had isolated rusting.
Failure of the HVAC steel would have caused exactly the type of collapse we saw (see my prior post above.)
-W
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
The review you quote showing rusting of the HVAC system was supposedly done between 8/01 and 9/06/2018 but was not received by the town of Surfside until "5:35 PM on June 24, 2021."
Otherwise, I agree with you. Maybe the unit wasn't anchored properly and a jolt loosened it, so that it wasn't the trigger but it helped precipitate the collapse. The reddit thread said there were two jolts about 3 minutes apart. Alternatively, it simply fell when the building fell and it wasn't involved in the collapse. Corrosion failure of an overloaded structure wouldn't be surprising. If the margins of safety had been greater, maybe many lives might have been spared. Finding that the columns weren't designed for the penthouse addition is a smoking gun.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
It looks to me that Morabito submitted it after the collapse, but originally prepared it alongside the 2018 report he did for the Condo. I'd guess he sent it in to be as helpful as possible and avoid any appearance of concealing anything from the investigation.
On the rooftop HVAC unit, I don't believe it's at the root of the failure. The photo of the steel frame corrosion in this unauthorized form report doesn't look severe enough to fail in 3 years. The location, directly north of the elevators does not fit with the start of the collapse in the security camera looking across from the new building to the south. The collapse of the upper levels appears to initiate around the x11 apartments and ramp to the parking garage, in the middle of the wing. The section closest to the elevators appears to be pulled into the collapse later, presumably pulling the HVAC unit and frame down with it.
"Gabe" from apartment 111, directly over the lower end of the ramp, seems to be saying that the pool deck slab out in the open had visibly collapsed while the building was still standing. He was able to escape with his family after seeing that, before the collapse. That progression doesn't really fit with the new HVAC unit being at the root. It suggests that the exterior pool deck failed at a column, progressed towards the x11 apartments, then pulled out a column or two below apartment 111.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
The HVAC unit was replaced with a larger and most likely heavier unit in a different location after the 2018 inspection.
Do we know which column on the x11 stack failed? Assuming it was a corridor column as the collapse seemed to start there. Those columns had an extra floor added to the roof for the walkway to the penthouse addition. The corridor column part of the collapse furthest to the east had both the penthouse walkway and HVAC frame added to it.
-W
RE: Miami Beach, Champlain Towers South apartment building collapse
Correction made.
Central American concrete. I once pulled over too far to the right and my door and rocker panel clipped a concrete pedestal that had once supported a lamp standard.
There was little damage to my truck. There was a lot of damage to the concrete.
Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!
RE: Miami Beach, Champlain Towers South apartment building collapse
If a column failure, or major deck damage is documented and not addressed for years someone needs to go to prison. That column alone should have been immediately shored up, ask questions later.
This was an entirely preventable event, thank god for extremely conservative redundancy factors, or we would see alot more of this.
RE: Miami Beach, Champlain Towers South apartment building collapse
I don't think the current public evidence gives any certainty around that. To me, the security CCTV from the south makes it look like the K,L,M columns were first to go in the upper collapse, probably rows 4,8,10 (I'd guess row 10 first, but it might have started at the corridor row 4).
The red HVAC support frame looks to be the same for both old and new. It appears to span E & H columns in rows 2 and 4. There's also the I series of columns between it and where I believe the earliest upper collapse is visible.
There's a fair bit of interpretation / guesswork above, trying to interpret the distant CCTV image which is looking diagonally across to it and it's all very quick. We can't rule the new HVAC unit out as one of many contributing factors, it just doesn't look to me that it was at the root of the failure or part of the early progression.
RE: Miami Beach, Champlain Towers South apartment building collapse
Looking at the video it appears that the column on grid I/9.1 was the first to go, although I can't see the interior columns to the north.
See attached snip from the lobby level slab. A couple of items regarding the yellow area and the column with the arrow pointing at it:
Lets say:
+10'-10" = pool deck level
+11'-10" = plaza level
+13'-4" = lobby level
1) this looks like a low point (+10'-10" only open to the pool area to the east) where the slab would seem to be at higher risk of corrosion. ;
2) there is a 2'-6" step in the slab at this column joint.
If the yellow area collapsed first or another area at pool deck level collapsed first then triggered the yellow area to collapse doesnt really matter I suppose. If the yellow area fell at any point I would start looking at some amount of lateral force being applied to the column between two supports (foundation/basement slab and the slab at lobby level).
Next, perhaps since all the columns along grid 9.1 are tied together with a beam at the slab step, if column I/9.1 (i.e. "the suspect column") collapsed first, that could potentially mobilize a force on grid 9.1 columns acting to the west, with load path bonus from the steel in the perimeter beam.
This seems to be reflected to some extent in the collapse video - the columns along grid 9.1 are among the first to go, starting at the suspect column and propagating east.
Also, I highly doubt any sort of mechanical equipment had anything to do with this.
RE: Miami Beach, Champlain Towers South apartment building collapse
Having done dozens of parkades... slope and drainage is a real engineering issue.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
The flashing light coming from next to the elevator roof machine room could be from the rupture of the power supply wires of the AC rooftop unit while falling down.
https://m.youtube.com/watch?v=KR29pLccutY
"Where the spirit does not work with the hand, there is no art." - Leonardo da Vinci
RE: Miami Beach, Champlain Towers South apartment building collapse
This is the most believable statement in this entire thread.
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Looking at the video it appears that the column on grid I/9.1 was the first to go, although I can't see the interior columns to the north.>
This is exactly the column that stood out to me.... It kinda looks from aerial that it could be where the planter was located 🤔 extra load and water infiltration and maybe not as easy to see during a visual inspection.
The waterproofing may not be a structural issue, but the slope and drainage definitely is a consideration and coordination that should always be considered. Even now I've seen lots of architects try to apply waterproofing to a flat slab and then "slope the finishes"..
Obv lots of speculation at this point, but as engineers our brain is trying to find an explanation to this horrible tragedy.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Surprisingly residents are still allowed to live in the building, given the witnessed catastrophe.
RE: Miami Beach, Champlain Towers South apartment building collapse
That's from https://youtu.be/qTUykkOSLEw
They say that's Champlain Towers East, which is the much newer of the three buildings (1994, I think), which makes it all the worse. Champlain Towers North is the one which is near identical and the same approximate age as the South tower that has collapsed.
That looks about head height, so unlikely to be vehicle damage, it must be corrosion damage. I'm not an expert on corrosion in RC, but up high on the column suggests to me it's probably coming from the slab above rather than rainwater from vehicles. I know how destructive the ocean environment can be, but that's scary. How bad is the pool deck slab as a whole, if that's the state of the columns supporting it?
I certainly wouldn't want to be within a block of that building right now, until it's been properly surveyed (and appropriately shored up / repaired).
RE: Miami Beach, Champlain Towers South apartment building collapse
If this is true for the South tower, then it may be true for the North tower as well (and maybe the East depending on whether the East tower has an added on penthouse also). You can find the "Typical Floor Plan Dimensions" blueprint for the North tower at page 164 of 336 of the 1979 plans. The "Column Schedule" for the North tower can be found at page 171 of 336 of the 1979 plans. The penthouse is also shown on the column schedule for the North tower to be floor 12. Maybe it was added also.
Given the picture of the lower level garage posted by Engr888 (which Murph9000 says is actually from the East tower), maybe somebody ought to consider evacuating the North (and maybe the East) tower until it (or they) can be shored up. Just a thought.
RE: Miami Beach, Champlain Towers South apartment building collapse
missstructures: To me it looked like the column line along the corridor went first due to the light flashes, otherwise the first portion to collapse would have tipped over more rather than fell in on itself. The rebar pattern also makes it appear a middle column failed. Did unit 101 escape into the pool deck, he had direct access. Finally, the pool itself looks undamaged.
Engr1988: is that North or East. East was built in the 1990s.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
On drawing S-9 (penthouse framing) and S-10 (roof framing) the drawings detail top reinforcing at these column locations.
EDIT: Drawing S-6 (second floor framing) also details top reinforcing at these column locations.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
To the current Australian code, since 1988, minimum concrete strength within 1Km of the ocean is 40Mpa (5800psi) because of the exposure to sea spray!
So I would be expecting bad corrosion a long time ago independent of any water leaks.
Typical floor slabs are flat plates, 8" thick spanning a maximum of 22'6", so about 6.9m and it is an end span. I would expect that sort of depth with a properly designed PT slab and 40MPa concrete, not an RC slab.
I do not have the complete drawings and design requirements, but from what I have seen, I would suggest the expected deflection on the typical floors would have been in the order of 100mm (4") if they had been correctly reinforced, and that is doubtful from the details we have so far.
And it would require significant amounts of shear reinforcement for punching shear, which I still do not believe is possible to make effective in an 8" slab and from the drawings I have seen has not been provided.
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
With salt de-icing, I use 35MPa min... with added cover. Does the Australian code have minimum cover requirements?
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
It has stood up for 40 years with its problems! It normally takes a lot more than one problem for collapse, but punching shear is very unforgiving once it decides to go. Pancake failure!
Yes it has minimum covers, but for that exposure it has minimum 40Mpa strength independent of cover.
RE: Miami Beach, Champlain Towers South apartment building collapse
Unbelievable. How would this even be a discussion?
This "40 years" is a completely arbitrary number as far as i'm concerned. What do the 40yr inspection reports of the other Champlain tower(s) say? Assuming they were built within a short time of each other. Or are they also just waiting a cool 2 years to take action on known issues. Critical issues.
Where does the inspecting PE's responsibility end? I.e., I feel like the findings of this report should have been followed up on. The inspection report has a forensic architecture flavor to it, not so much structural.
RE: Miami Beach, Champlain Towers South apartment building collapse
I'm sure every building of that era will be looked at a bit more closely now. I could see even a mass inspection and required retrofit similar to what many jurisdictions in California have recently required.
RE: Miami Beach, Champlain Towers South apartment building collapse
Dr. Atorod Azizinamini, a structural engineering professor from FIU, is advocating a much better approach than 40 years:
https://youtu.be/pex8u5NfWYs
I encourage you to watch his video in full, his thoughts on this disaster are worth your time. The short version, however, is different levels of inspection at 5, 10, 25 years, or something like that; so you have an expert eye taking a quick look far more often, and a detailed examination at longer intervals.
RE: Miami Beach, Champlain Towers South apartment building collapse
I apologize if I seemed flippant about the design of the Parkcade (I really love that term), it was not my intention. What I was trying to convey is that failures during construction, or soon after completion are different than a structure that has been up for 40 years.
I totally agree that the bars appear to to not have has adequate concrete coverage and became unbound to cleanly from the slab/deck. this in not engineering 101. This is a pretty specialized forum, and I think that the general level of discourse reflects that. My point is that there is a huge knowledge gap in understanding structures such as a Parcade between the members of this forum, and the general public.
We are a self regulating industry, and I would wager a $2 bill that several members of this forum are either current active members or former members of at least one code committee.
In my opinion I feel that we fail the public post construction, in terms of inspection, and maintence codes for mid to high rise residential buildings.
There is no doubt in my mind that the people are actually reading this, could have prevented the loss of so many lives.
The type of professionals that participate (myself included) in discussions such as this, are the ones that write the building codes, so in a sense we are all responsible for this catastrophic event.
RE: Miami Beach, Champlain Towers South apartment building collapse
https://twitter.com/OfficialJoelF/status/140798540...
Is there a ok plan showing the apt #s?
RE: Miami Beach, Champlain Towers South apartment building collapse
"Suddenly she says, 'honey the pool is caving in, the pool is sinking to the ground'," "He said 'what are you talking about?'
And she says, 'the ground is shaking, everything's shaking' and then she screamed a blood curdling scream and the line went dead."
Link:
https://news.sky.com/story/miami-building-collapse...
In 2018 MC [Morabito Consultants] Structural Report recommends that the Entrance/Pool Deck concrete slabs that are showing distress be REMOVED & REPLACED in their entirety.
Link:
https://www.townofsurfsidefl.gov/docs/default-sour...
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.reddit.com/r/CatastrophicFailure/comme...
RE: Miami Beach, Champlain Towers South apartment building collapse
Separately, as was mentioned earlier, NIST investigators are on the scene. This from yesterday.
RE: Miami Beach, Champlain Towers South apartment building collapse
Wow... that's an interesting way of handling being rather direct and potentially hostile to a guest here... calling someone a "troll" on account of them using a commonly harmless idiom that only
might be pejorative or mocking. I've never heard of a such a thing. Good grief is an expression of surprise, dismay, alarm or other emotion. The only one who has the right to be upset might be God since it's derived from Good God...
In any case, thanks for pointing that out. Intriguing.
Thanks for explaining the report's discussion of "structural damage". I wasn't clear on what the report was referring to when they said that. But now I am.
RE: Miami Beach, Champlain Towers South apartment building collapse
No need... wasn't taken as such... I just wanted to let people know that drainage is critcal for parkades... generally to minimise corrosion issues. Also need good expansion joints. You either install cheap ones, or ones that work.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Thanks rapt... in Winnipeg, we typically have one freeze-thaw cycle per year...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Corrosion is supercharged in spots where it's constantly damp and constantly exposed to air. You can see this very visibly on steel canal boats. You get a roughly half inch band of much faster corrosion at the waterline; the metal that's constantly submerged is good, as is the metal that's generally above the water. That's with sacrificial zinc / magnesium anodes welded to the hull to slow it down, and reasonable attempts to protect it with coatings. Just giving this as a practical example where you can see it in action.
A flat surface that doesn't properly drain / dry out is creating that sweet spot for rust.
RE: Miami Beach, Champlain Towers South apartment building collapse
He simply asked if you were being one... Your kurt comment could not have been taken another way, IMHO. I ignored it. Let's drop this.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Your typical 'real' load on a parkade structure is in the order of 15psf to 20psf as a maximum load and I use these values for alternate LLs.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
We have a couple of months in both the spring and the fall with a daily freeze thaw cycle. The daily freeze thaw cycles for a thermal mass are very much shorter. Is that what you were refering to?
By the way; Does Portage and Main still claim the record for the coldest intersection on earth?
Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!
RE: Miami Beach, Champlain Towers South apartment building collapse
Seems that way.. but, there are likely colder intersections in Siberia, etc. Winnipeg is colder than Moscow...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
This topic is (unfortunately) interesting.
I note that two witnesses appear to be saying that the "pool deck" failed first, by perhaps a minute or more. To me, the pool deck is the expanse between the pool and the building. Photos show it surely did drop, by one level, I think.
I propose that by having that floor drop, there was then, for the soon to fall building(s), nothing to keep the intersection of their columns at that same level from moving towards the south (towards the pool deck location). I am assuming a solid sheet of concrete across the whole expanse, and I believe it likely there was a garage under the whole thing. The building could stand until some perturbation caused the sideways movement of those points on the columns, and they fell.
spsalso
RE: Miami Beach, Champlain Towers South apartment building collapse
MJCronin
Sr. Process Engineer
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.youtube.com/watch?v=BvkRmtmB-Fw
RE: Miami Beach, Champlain Towers South apartment building collapse
One of the witnesses was in one of the buildings that fell, and said something about the pool area acting funny. So it surely seems like that HAD to have happened first.
spsalso
RE: Miami Beach, Champlain Towers South apartment building collapse
That would explain the sudden collapse if several columns were able to fail nearly simultaneously
RE: Miami Beach, Champlain Towers South apartment building collapse
Link
RE: Miami Beach, Champlain Towers South apartment building collapse
The Miami Herald is doing it's usual job of excellent reporting and asking "experts"
See what experts say is the probable sequence of collapse at the Florida condo tower
To go to the 3d model directly:
Champlain Towers South
Less than I expected, but for the time being useful.
SF Charlie
Eng-Tips.com Forum Policies
RE: Miami Beach, Champlain Towers South apartment building collapse
Nothing specific on the current event is posted on the NIST site yet.
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Very interesting that the majority of structural retrofitting (add drop panels, columns, etc) is in areas that didn't collapse!
It's seems the 40 year inspection system was working. The issues were identified, the plans were being created. I guess the lesson here is 40 years is too long.
RE: Miami Beach, Champlain Towers South apartment building collapse
Sometimes, maybe... but the phonecall is pretty solid.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://imgur.com/gallery/lvlxnr6
RE: Miami Beach, Champlain Towers South apartment building collapse
https://nypost.com/2021/06/26/florida-survivor-rec...
Video interview (en Español):
https://www.univision.com/local/miami-wltv/tenia-q...
RE: Miami Beach, Champlain Towers South apartment building collapse
Even a perfect vertical drop is likely to do a little damage to the column as the joint detaches. It's not difficult to see a mostly vertical drop giving the columns a little kick or pull at some point between detaching and landing on the slab below. The doubled vertical span has much less safe capacity, and probably has a bit of fracturing at the mid point. There's a fairly big chunk of energy moving around as that slab fails and falls, regardless of the precise way it falls. The column can't just let go of the slab, there's forces and release of both tension and compression as it happens.
If the structural system as a whole was a bit too close to limits, a little extra damage could be all that's needed for the next step in the progressive failure.
Combined with multiple witnesses reporting the pool deck failing first, it's likely more on the contributing than result side of the collapse.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
It seems that the time of the main collapse could be picked off of the video recording we've seen.
For the pool deck, I wonder if something might show up in the electrical metering record, or maybe some kind of alarm system. I imagine the garage was piped for fire, and that the pipe broke. That might give a time stamp.
spsalso
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
The terms you use, freeze and thaw and de-ice, are foreign to Australians for construction. Freeze is how we preserve meat. Thaw is what we do before we cook it. De ice is what we put in de glass before de whisky.
RE: Miami Beach, Champlain Towers South apartment building collapse
Just incredible that people were walking by this on their way to their bedroom without any concern or alarm...
I'd be checking on the ground beneath it to see if there is any debris. That alone would certainly get my attention.
Is this part of the structure that is still standing? or another separate building nearby?
RE: Miami Beach, Champlain Towers South apartment building collapse
Same here, as far as meat...
In some northern or very southern (polar) areas there are several months where the temperature falls below freezing 0deg C (32F). At the beginning of winter and at the end, the temperature fluctuates where the temperature is above and below freezing. These fluctuations are called freeze-thaw. With moisture in concrete, this alternate freezing and thawing causes deterioration called freeze-thaw damage. We use air entrainment in the concrete to minimise the damage.
Because of ice on the roads during winter, some places use a mixture of salt and sand to provide traction. This is called de-icing salt. The salt causes corrosion of reinforcing steel in concrete structures. Damage caused by corrosion in minimised by using a high strength concrete, admixtures and thicker concrete cover to the reinforcing.
Hope that explains it...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
or that the matter was not brought to the attention of the authorities...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
I'd be checking on the ground beneath it to see if there is any debris. That alone would certainly get my attention.
You have to remember that those of us here are engineers, the majority of if not all of the people who lived in this building were not technically oriented people. Thus they had no idea that if I saw stuff like this it was actually a problem for the buildings integrity.
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Also, in many areas epoxy coated rebar is used to limit the effects of salt on the rebar.
RE: Miami Beach, Champlain Towers South apartment building collapse
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
that too, there are a couple of issues with epoxy coated bars... the bond strength is diminished, and they are more costly. They
domay (see below) work, but you have to use extra care in handling them. Nicking the coating can accelerate the corrosion at that location. Most roadwork and bridgework I've seen done in the last decade or two have used epoxy coated bars. Most regular construction, including parkades use conventional 'black' iron bars.Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
The theory is that the epoxy coating wears down in the alkali environment of the concrete in about 30 years. Based on the concrete cover used on bridges - about 3" (75mm), but depends on location - it takes about 30 years for the chlorides to reach the reinforcement. So basically, just when you need the Epoxy Coating to work - it no longer works.
Our Concrete people always say that strength = impermeability is old-school. Many DOT's now specifically have permeability requirements and don't rely on the loose relationship with strength. Rapid Chloride Penetration (RCP) is the test done - but it is not that rapid as it usually takes 56 days.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
https://images.wsj.net/im-360760?width=1260&si...
RE: Miami Beach, Champlain Towers South apartment building collapse
Thanks
SF Charlie
Eng-Tips.com Forum Policies
RE: Miami Beach, Champlain Towers South apartment building collapse
She reportedly yelled "honey the pool is caving in, the pool is sinking to the ground".
From the recent photos, the swimming pool doesn't look very much like it's caving in or sinking. it looks surprisingly intact.
RE: Miami Beach, Champlain Towers South apartment building collapse
And you are paraphrasing a quote of someone who was paraphrasing a quote of someone whose loved one was talking while in the process of being killed by a progressive building collapse that they were trying to make sense of after being woken up at 1:30 in the morning.
What’s your question?
RE: Miami Beach, Champlain Towers South apartment building collapse
Also, not sure where she was in the building.... and how one could see that pool actually caving in.
I'm assuming the story is authentic.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
FWIW, it does look like the very small pool (jacuzzi?) has drained.
RE: Miami Beach, Champlain Towers South apartment building collapse
Also, a former mainentance manager from 1995-2000 who worked at both the South and North towers claims the South tower lower level garage would flood with saltwater during king tides and it was so bad the cars would be floating down there:
https://youtu.be/gh7cnY7PkLU?t=312
He goes on to say the North tower did not exhibit this issue. It's not a smoking gun, but if true, it is another example of there being serious saltwater infiltration issues going on at the property beyond just the improperly sloped promenade deck by the pool.
RE: Miami Beach, Champlain Towers South apartment building collapse
The heater failed on my underground stock watering system.
I froze up in the fall and thawed the next May.
The frost goes down a long way and the earth is slow to warm up.
Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Please find me the URL, and I'll sleuth it out.
SF Charlie
Eng-Tips.com Forum Policies
RE: Miami Beach, Champlain Towers South apartment building collapse
Thanks
SF Charlie
Eng-Tips.com Forum Policies
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Where are Phase IA, XX, XXX etc plans? Where are the Phase IIA Plans.
I may have used a golf club to “sound” the walls and ceiling, but don’t think I would have mentioned the club, only the results in the report. Rather brings up an image of the inspector wearing golf clothes with white shoes.
Steve
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
https://www.miamiherald.com/news/local/community/m...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
I looked and tide levels vary about 2-1/2' pk-pk and nothing special that day. https://tidesandcurrents.noaa.gov/map/index.html?id=8723214
Sea level trend +2.39mm/yr https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?id=8723170
https://youtu.be/gh7cnY7PkLU?t=316
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
"Jim McGuinness, who made the comment during a Town of Surfside emergency meeting, said he was on the roof to inspect work of replacing roof anchors, which are where window cleaners attach their equipment."
Modern roof anchors are tied to the structure of the building due to the 5,000# OSHA requirement. As far as I understand, there is not a way possible to meet this requirement without tying back to the building structure. The 2018 report noted to install anchors prior to commencing work, this report was flawed, the structure needed to be strong enough to add the anchors prior to adding them. Now, looking at the roof anchor permit drawings, they seem to indicate jackhammering directly into the tops of these overloaded & distressed columns from the roof (see comments above.) This was apparently happening within 14 hours of collapse. Do we know which columns were worked on? If the building was cracking for days why didn't the inspector know.
Finally, the firm that did the structural review of the building also did the structural drawings for this work, I personally think this is a conflict of interest. For example on every project I am a part of I instruct the owner to use a separate surveyor and civil, the surveyor catches a civil error every time (seriously.) They all have the young guys drawing and the older guys are hustling work barely checking. It's simple and important stuff. While we are much more precise than the hand-drawn days, CAD isn't perfect, it's only as perfect as the operator. I can recall the many times I have caught a consultant missing the thickness of a double-sided plywood shearwall. I'm thankful the framers are using Revit now and building a model themselves.
While I'm not part of a code committee yet, I have been licensed for many years, and I feel we really need to simplify the code for younger architects and engineers to understand it, or at least add pictures of what the committee means IN THE CODE! And, existing buildings need more than just a code, we need to force those who adopt IBC et al to review existing structures more often somehow. I have previously worked at an architecture office in Santa Monica where there is visible earthquake damage (cracked beams) and ownership doesn't care. They don't have to, unless they are forced to. This collapse won't be the last unless we fix the process, the boomer days of its standing don't touch it need to end.
-W
RE: Miami Beach, Champlain Towers South apartment building collapse
The roof anchor drawings you reference show this detail for the "column anchors':
Two x 7/8" dia percussion drill holes @ 5" deep is not very destructive. Probably drilled with a 30lb electric percussion drill. Also, it is the ROOF LEVEL - highly unlikely the upper level columns were "overloaded and distressed".
I may have an different opinion if they were drilling a lot of holes in BASEMENT columns if there was significant visible distress, but they were not.
RE: Miami Beach, Champlain Towers South apartment building collapse
"In 1997, on a routine inspection of the building, appellant found significant movement "internal to the building" on the fifth floor. It retained Whitney, Bailey, Cox & Magnani, consulting engineers, to inspect the building. That firm did so and concluded that the design team for the renovation, which included Morabito Consultants, Inc., had failed to calculate properly the increase in live loads associated with the change in occupancy of the building. As a result of the increase in loads, the truss system was overstressed. -- College of Notre Dame of Maryland, Inc. v. Morabito Consultants, Inc., 752 A.2d 265, 268 (Md. Spec. App. 2000)"
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
That suggests the collapse started before what we've seen on the CCTV footage.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
The combined witness statements all point to some sort of failure of the outdoor pool/patio/plaza slab prior to any major collapse involving upper levels. It's hard to say how much in advance, but it seems to be at least a minute or two, possibly as much as 15 minutes for the first signs of it. The CCTV footage from the south that's widely circulated only includes the upper collapse. It would be very interesting to carefully review the preceding hour from that camera for any movement or dust.
Some details don't quite add up, like "holes where the elevators were", since the elevator shaft is still there and appears largely intact. They are not necessarily trying to embellish or be deceptive about it, as this would be them trying to make sense of a chaotic scene with dust and destruction all around. The brain has difficulty processing what it's seeing, and constructs a memory as best it can while running on adrenalin in survival mode.
I think Willis was probably in the surviving section of the building, and the dust was from the main collapse.
RE: Miami Beach, Champlain Towers South apartment building collapse
RE: Miami Beach, Champlain Towers South apartment building collapse
1. The Cooling tower at the roof level was changed out. Normally these things are about 20-30 kips for a building this size and distributed over 2-4 columns. For a concrete building this size, and with typical live load reduction - its not likely the cooling tower would over load a concrete column (unless said column(s) was severely deteriorated). I dont think that is likely.
2. Roof Anchors/Fall arrest system installation. If this was a post-tensioned building and the contractor repeatedly knocked out tendons with drilling operations, I could see this being plausible. But other than localized damaged/deterioration around the anchors, they are rather non-obtrusive in the short term. One minor comment on that design, I'm sort of surprised the original engineer went with a 2 anchor design - I had assumed the 4 anchor OSHA minimum would apply to fall arrest systems.
RE: Miami Beach, Champlain Towers South apartment building collapse
Developers of doomed Fla. tower were once accused of paying off officials
https://nypost.com/2021/06/27/developers-of-fla-to...
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
Hypotheses?
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
RE: Miami Beach, Champlain Towers South apartment building collapse
Brad Waybright
The more you know, the more you know you don't know.
RE: Miami Beach, Champlain Towers South apartment building collapse
John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: Miami Beach, Champlain Towers South apartment building collapse
That is Champlain Towers EAST, between South and North, that is still OCCUPIED at this moment. Built in 1994, but does not seem to have the penthouse which added load that the columns were not designed for. Even without the penthouse, I'd recommend evacuating EAST and ordering a full structural inspection. JMO