In the early morning hours of June 24, 2021, half of the 12-story Surfside Florida luxury condominium, Champlain Towers South, came crashing to the ground, killing 98 occupants.
In a recent public update, the NIST detailed the lengthy work needed to uncover the causes of this collapse.
This includes building design, construction, modification, and deterioration analysis, evidence preservation, remote sensing analysis using data collected with tools such as LIDAR during recovery, material tests on recovered evidence, a geotechnical analysis of the surrounding soil and geologic conditions, as well as detailed structural and failure analysis using computer modeling.
Additionally, they will interview people with historic knowledge of construction in south Florida, and continue to accept information from the public that could shed additional light on this tragedy.
Although answers from NIST's investigation will not be forthcoming for a number of years, many individuals unrelated to the NIST have combed through publicly available information to find possible causes.
While precise triggers leading to the collapse may never be known, most public evidence, as this video demonstrates, points to two key factors: Badly neglected and deteriorated pool deck concrete slab that lead to a pool deck collapse, and resulting damage to three key building support columns that lead to the building collapse minutes later.
A timeline based on public witness accounts, details the dramatic events of that morning.
In an interesting twist, this USA Today article digs deep in to possible drug related money laundering and corruption surrounding the building's construction.
AP News reports a lawsuit that was just filed alleges previous construction next door contributed to the collapse.
Most of the media has focused on the lack of "answers" from the NIST and other organizations. Youtuber Jeff Ostroff has compiled an informative explanation of who NIST is, why the NIST is investigating, and why this takes so long.
(Score: 5, Informative) by SomeGuy on Saturday November 20 2021, @07:37PM (18 children)
Somewhere there was also an article that detailed numerous possible contributing factors, but I could not find that one again off hand. Here are some notes from what I have read:
Contributing factors:
Design flaw (although standard practice) - At the building edge, the support beams for the pool deck were not separate from the building support beams.
Design flaw - there was no waterproofing in the ground level parking/drive through area slab. (which was also the garage ceiling at the side closer to the street).
Design flaw - there was no waterproofing in the original pool deck slab, as shown in a recent core sample. A layer of water proofing and new tile was later added over the old tile, which is was not the right way to do it and possibly made things worse.
Design flaw - the pool deck water proofing was not designed to slope down to allow proper drainage. There may have been other drain issues too.
Design flaw - overcrowded rebar in many columns. Insufficient rebar in other. (overcrowding results in weaker columns that may deteriorate quicker).
Design flaw - some designed supports were removed at the last minute due to a feature removal. But these supports may have had alternate purposes.
Design flaw - the pool deck design placed it at exactly 100% capacity.
Design flaw - when the pool deck water proofing layer was finally added in (what year was that?) it was sloppily added over the old tile, and to hide that it was covered with a layer of SAND and concrete pavers placed on top of that. The sand would have retained water, that besides damaging anything that leaked through, the water, sand, and pavers massively added to the weight of the pool deck, which was already over its limit.
Implementation issue - after design and construction, an extra penthouse level was added.
Implementation flaw - extra, extremely heavy, planters not in the designs were added to the pool deck, placing it over 100% capacity. For a while, some of these planters held very large palm trees, and the roots damaged the concrete.
Damage - Excess exposure to moisture from previous flooding damaged and weakened most of the garage level beams and deck level slab.
Damage - At various times, heavy vehicles may have entered the pool deck area. Since it was already over capacity, this would have likely caused cracking.
Damage - There were many cracks visible in the garage ceiling (bottom of pool deck), water leaking through, and water pooling on the garage floor.
Damage - The recent pool deck slab core test incorrectly cut through rebar.
Damage - The area of that recent pool deck slab core test may not have been repaired properly.
Damage - The pool deck water proofing had deteriorated.
Damage - The pool deck concrete slab was disintegrating/"delaminating".
Contributing factor - The building roof had issues with water not draining properly, causing roof damage.
Contributing factor - Construction crews had just started work on the roof, placing heavy equipment on the roof.
Contributing factor - A few years prior, a new building had been built next door that created excessively large vibrations.
Contributing factor - In addition to roof/penthouse weight, residents may have added significant weight when remodeling, such as marble flooring.
Also, some debunked theories:
Debunked theories about condo collapse
Pool Equipment Room damage - this was thrown around by the media the first few days because those photos were the only photos they could get their hands on. While representative of the problems there, this location was very far away from the collapse center - a narrow corridor at garage level between the pool and the garage/foundation wall. The irony is, even after all the building debris removal, the pool and this room behind it is more or less STILL THERE.
Sinkhole - Although very tiny amounts of sinking or instability could have factored in, once the debris was removed, exposing the empty and dry garage floor, it was obvious there was no sink hole.
Explosion - No evidence of a bomb or explosive material has been found or reported. No evidence of any fire prior to the collapse either.
Earthquake - That is Florida. No earthquake was recorded, although residents reported it felt like an earthquake.
Objects falling from roof - It is unlikely any objects fell from the roof prior to the building collapse. Even if it had, that would have only been a trigger and not the underlying cause. Supposedly a complete high resolution version of the next door security camera video exists that would easily prove or disprove that.
Falling balcony - although some balconies had cracks, there is no evidence any were bad enough to fall.
Car running in to garage beam. - A car running in to a beam would not be able to produce enough force to significantly damage a beam. That also would have left clear evidence of a car wrapped around a beam.
Maniacal 'toon dropping a grand piano on to the pool deck from a penthouse balcony, the garage video missing beam then walked away making accordion sounds. Nah.
As mentioned, the generally accepted theory:
Pool deck and concrete beams were weakened and damaged over 40 years of exposure to water, in addition to numerous design flaws. A single beam or slab simply reached a literal breaking point and started a chain reaction that collapsed the entire pool deck. Falling horizontal lateral support beams in the pool deck acted as a lever, damaging beams that supported the building. Connections between floor slabs held the building up for a few minutes before they became undone.
The only "trigger", as such, might have been excess water collecting on the pool deck from the recent rain. This would have added very significant additional weight.
Given that most of the important evidence ended up pulverized at the bottom of the pile, I have a feeling the final report may be more one of exclusion. That is, it was not a bomb, it was not an airplane ramming in to it, and so on.
(Score: 5, Interesting) by VLM on Saturday November 20 2021, @08:16PM
NIST also gets involved outside incidental engineering.
So there's big questions about inspection processes and how they should change. It seems they already found anomalies between the prints and the remains. Now, there's never been anything built to plan other than maybe some aerospace projects where money is no object, and even those are iffy. So its not as simple as "one piece of rebar was missing we'll throw all the blame there and call it a day". Supposed to design in redundancy. Engineers are so pessimistic about electrical safety they run ground wires to every receptacle, theoretically those ground wires will never carry a microamp over the life of the installation, as an extreme example. So its not enough that they F-ed up some rebar, its that they F-ed up enough rebar to collapse the building after a long time, thats ... odd design situation.
There is building code advice to avoid progressive collapse; its not inevitable that one domino tipping over guarantees complete collapse. In fact its an excellent question why the collapse STOPPED when it did leading to the necessity to demolish the remainder of the building. Its possible they'll invent new standards for building codes and engineering textbooks to avoid progressive collapse based on this incident, which will certainly take time to research. Its not inevitable that a small piece of concrete falling would pull over column after column. For example, apparently someone, whom later died, called on her phone to report a giant hole appeared in the deck a couple minutes before the overall building collapsed. That's the way its "supposed" to work, one slab section cracks, no biggie, redistribute load across other columns, its all good, the building should still be standing today, perhaps with that hole still in the deck. The failure wasn't that that hole in the deck appearing, the failure was the rest of the building was not supposed to continue the collapse minutes later.
It seems "everybody" knew this building was hopelessly fucked for years but nobody wanted to look closely enough to condemn it. Lets have someone else be the bagholder, someone else can eat the financial losses, if it just holds together another year, decade, century... So that's an interesting process failure. The problem isn't that it collapsed, its that it collapsed full of people. Why not condemned back in '18 or some other period in time? This is a whole nother research project.
Another problem is any project that's big will always have multiple unrelated failures. So its possible simultaneously that the slab was delaminating, which is really bad, and that delamination never killed nobody and never would have, maybe the failure all along was how the columns attached to the slabs or whatever. That seems to be the problem with the nearby construction project; yeah I'm sure pile driving F-ed up the building, at least knocked pictures off walls, but did it provably F up the building causing the collapse, thats the puzzle that takes a lot time to figure out.
Although this borders on conspiracy theory, Florida gets a huge number of thunderstorms and one of the many "meh" engineering related possible factors I've read is I know for a fact that poorly bonded rebar when whacked by lightning can in some circumstances screw up the concrete in commo tower bases. Supposedly it would be pretty easy to observe the lightning related damage in the remains IF that were a contributing effect. Obviously lightning didn't hit it and cause immediate collapse but the idea was a lighting strike years ago could have caused cracks that then filled with water and corroded for years etc.
(Score: 5, Interesting) by Thexalon on Saturday November 20 2021, @08:25PM (11 children)
I'd also add to the list of contributing factors, luckily one that appears to be getting some appropriate attention [apnews.com]: A lack of a consistent system of building inspections with enough enforcement to create a financial incentive to not fix the design flaws and damage.
I don't particularly care if said building inspection system is run by the government or by insurance companies, but either way the key to preventing repeats of this disaster, or the Grenfell Tower Fire, or similar failures is to make it more expensive in the short-term to not fix problems than to fix them. Apparently, the condo association was debating how to pay for repairing some of the relevant damage shortly before the building collapsed - I'm guessing there would have been a lot less of a debate had a failure to do the necessary repairs cost them more in either insurance premiums or fines than it was going to cost to get the work done. Otherwise, there will invariably be advocates for rolling the dice instead of fixing the problem on the grounds that they don't wanna pay.
I'll admit I'm far from objective about this: I know personally a guy who lost a family member in this event - not a resident with any decision-making power in any of this, just visiting an old friend. I don't think they even recovered the remains.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 2) by MostCynical on Saturday November 20 2021, @08:41PM (4 children)
First the president of the condo board quit in 2019 as squabbling residents refused to pay.. [washingtonpost.com]
then most of the board also quit [businessinsider.com]
1 July 2021 · Most of the collapsed Florida condo board members resigned in 2019 amid disputes about the cost of repairs that never went ahead ·
"I guess once you start doubting, there's no end to it." -Batou, Ghost in the Shell: Stand Alone Complex
(Score: 3, Insightful) by Thexalon on Saturday November 20 2021, @08:44PM (3 children)
And that's exactly my point: So long as not paying was a viable option, some people weren't going to pay. Faced instead with options like "pay more for building insurance" or "building is condemned and they have to move out", they might change their minds about paying for repairs.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 4, Informative) by RS3 on Saturday November 20 2021, @10:21PM (2 children)
EE, not AE, but I did have a fairly famous AE professor for "statics" (beams, loads, etc.) classes. In my humble non-CE opinion, based on what I had seen in a youtube video where some AEs analysed the construction, that building should have been condemned long ago. As OP mentions, some major critical columns and beams had too much rebar, some not enough. And some major critical beams were moved, resized (shrunk), and some other things changed that completely changed the structural loading.
Most often, "engineering mistakes" are actually construction / implementation mistakes, shortcuts, redesigns without approval, etc. One that still astounds me is worth a read (or skim):
https://en.wikipedia.org/wiki/Citicorp_Center_engineering_crisis [wikipedia.org]
I'm stunned by what they had to do to correct it.
(Score: 2) by krishnoid on Saturday November 20 2021, @11:11PM (1 child)
I've read this and posted it before, but this little tidbit [wikipedia.org] truly astounds me:
No "I'm just going to let my lawyer deal with this if you want your money back" or "here's my report, now excuse me, I have a flight to [undisclosed country] to catch".
(Score: 2) by optotronic on Sunday November 21 2021, @03:09AM
I agree, but it's sad that we're so surprised by people accepting responsibility for something they made.
(Score: 2) by krishnoid on Saturday November 20 2021, @11:47PM (5 children)
How about putting up cameras or drones around the construction site, and requiring all such footage, including that of all support/electrical/et al components put in, to be available (minus anything showing a person, to avoid surveillance considerations) to anyone considering buying/insuring new construction? You could also have people remotely review each floor as it goes up, and if any corners were cut, you could see it, modulo things like substituting braided Slim-Jims for rebar or other stuff you could fake visually.
(Score: 2) by RS3 on Sunday November 21 2021, @01:36AM (4 children)
Normally licensed inspectors check everything out during each step of construction. I've done some construction work, and in my experience there's a (wide) variance in inspectors. Some nitpick to absurdity, like, the guy was actually wrong, but it was easier to accommodate him than to try to prove him wrong. And some literally did not get out of their cars- just filled out and signed paperwork and handed out stickers. I know we did (do) really good work, but for sure not everyone does.
Of course you'll get people adding / changing things after an inspection, so your camera idea would be good to catch that. But someone has to review the footage.
Maybe a variation of your idea: take still shots of things, from the exact same spot, at many times during a project, and compare the changes. That way if an outlet is added or a beam deleted or shrunk, you might catch it.
Last couple of wiring gigs I did, I took quite a few pictures (just in case).
(Score: 3, Interesting) by krishnoid on Sunday November 21 2021, @02:58AM (1 child)
Still shots, like a time-lapse? Sounds like a great idea, and it would be pretty cheap [fandom.com] to do. Also makes sense to take photos when laying out wiring. I never did it myself, but when a neighbor said he was remodeling and putting some drywall back up, I recommended he take a couple measuring tapes, play them out along the wall perpendicular to each other, and take a bunch of photos of the entire wall. That way a few months after the drywall is back in place, you can at least estimate where things should be behind the wall.
(Score: 3, Informative) by RS3 on Sunday November 21 2021, @03:43AM
Yes, very good.
Fortunately we now have RF transmitter / receiver tool pairs for tracing wires, often called "toner". I've used them to trace wires through their meanderings in buildings. https://www.amazon.com/electrical-toner/s?k=electrical+toner [amazon.com]
(Score: 2) by Thexalon on Sunday November 21 2021, @03:49AM (1 child)
And I can guess which ones were the ones shadier construction companies in particular tried to get whenever possible.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 2) by RS3 on Sunday November 21 2021, @07:00AM
Well, yeah, but shady or not it's human nature, for business-types anyway, to cut costs and corners as much as possible. To them it's all just a game to play and win.
And factor in that some workers are lazy and/or incompetent to some degree.
Most people hope / expect / assume inspectors are doing their jobs, and are fairly well monitored by govt.
Some years ago I went to a state-wide meeting for solar PV system installers. There were only 2 or 3 state employees running the program for the whole state. Inspectors needed some training and additional certifications for PV inspection, but it's mostly common sense electrical wiring. I actually felt sad for the state govt- the moderator / program head said they were trusting us to follow the rules, guidelines, etc., and basically be self-inspectors. I don't quite know how to verbalize it, but I just feel very badly because they (state govt.) must be good but naive people to think the installers are 1) competent enough, 2) care enough, and 3) not pressured by greedy business owners.
(Score: 5, Informative) by Kymation on Saturday November 20 2021, @08:43PM (4 children)
One report not mentioned here provides an explanation of the core samples and why they were not repaired. In October 2020 the condo association (finally!) hired a contractor to repair the damaged pool deck. The contractor extracted those core samples under the direction of the engineer who was also hired by the condo association. The contractor examined them, then stated that the pool deck was so badly damaged that any attempt to repair it would cause the whole thing to fail catastrophically, and refused to continue with the work. The contract was reportedly valued at $9.4 million, so they would not have made this decision lightly.
I believe this was reported by NBC, but I have a supporting link.
(Score: 1, Interesting) by Anonymous Coward on Saturday November 20 2021, @09:17PM (2 children)
I lived in a place once where our gas water heater was essentially "condemned" by a contractor, even though they were not city workers. The unit could not be used until it was repaired, possibly re-inspected by the city. My memory is a bit hazy, as I was a renter so you get that benefit of it being "not your problem". In any event, the thing was safely repaired but I was impressed with the idea that some contractors could, in effect, be "deputized" to condemn things within a building, if not the building entirely. I'm not sure if that power would have been used by the contractor in this case if it were available; but it sounds like something they might want to look in to. Of course there's potential for abuse there--contractors holding the building hostage, but you wouldn't be required to use the same guy, others could dispute it (putting their bond in jeopardy if it turned out you were just bribing them, etc.). In other words, more eyes and a more clear procedure to condemn things that are truly unsafe might be helpful.
(Score: 2) by Kymation on Saturday November 20 2021, @11:05PM (1 child)
Either the contractor or the engineer should have reported this finding to the city building department. I would not be surprised to find that this was done and the city did nothing. If it was not reported then the engineering firm and/or the contractor could be liable.
I once found that a house that I was looking to buy had slid several inches downhill. I reported this to the city, but they did nothing until a landslide started under that house several years later. While this is only one case, I have heard many stories of similar results. To be fair, the city probably doesn't want to get into an argument with a property owner over something that may or may not indicate a serious problem.
(Score: 2) by SomeGuy on Sunday November 21 2021, @12:27AM
Something to keep in mind is Surfside, where Champlain Towers South was, is actually very tiny self-run town right on the back of Miami. (I've read that the town of Surfside evolved a long time ago from some kind of exclusive beach club) They have their own building department and they were already in some hot water. Reports of issues in 2018 were shrugged off claiming the building was in "Good Shape".
(Score: 2) by SomeGuy on Sunday November 21 2021, @07:16PM
I've seen that core sample report referenced elsewhere, but apparently they did not go in to any more detail about what the the issue was, why they stopped, or what they would do next.
It does make sense that if they thought their repair, even though tiny, would fail for any reason, that they would stop and not complete it.
It also makes sense that if this discovery in any way changed the scope of work that they would have stopped in order to at least re-evaluate the scope of work.
It also makes sense that if the discovery itself was outside the original scope of work that they would not have included details in the report.
So the big question is, when they talked about surrounding structure being "unstable", did they mean as in "holy shit this building is going to collapse" or just "more work for us and more residence may have to find somewhere else to park while we work".
(Score: 4, Informative) by Runaway1956 on Saturday November 20 2021, @07:40PM (1 child)
I watched one recently, who deduced that the building fell because a series of columns were offset from the bottom most column. Basement driveway area had 5 columns supporting a beam, and the first floor column was positioned incorrectly beside that beam. That first floor column was duplicated to the next-to-top floor, which didn't have that same supporting beam.
All they need to do is call in Youtube to solve any mystery.
(Score: 2) by SomeGuy on Sunday November 21 2021, @06:56PM
Youtube and such sources can be great for exposing pieces of information or ideas that the mainstream media does not want to talk about. But at the same time there is lots of erroneous mis-information from people who don't want to consider all possibilities.
The public at large do not have "all" of the facts and can only make wild guesses. If you want solid, rock hard answers, you need a paid professional engineer that has direct access to evidence and the ability to directly analyze it. That is what the NIST is doing, and even they don't have as much information as they really want. Apparently, the "as-built" plans are missing and it is a little late to analyze the building itself.
Jeff Ostroff's videos are usually very informative, but he ocasionally dives in to unfounded conspiracy theories. There is another youtuber posting about the collapse that is a complete rambling idiot and should be ignored - originally I thought that guy was just making parodies of Jeff Ostroff's videos, but I guess that guy really is that crazy.
I'm guessing you are talking about that now infamous "H" transfer beam. First, that had squat to do with the initial central section building collapse. At best any design issues there would have slightly changed the probability that the eastern most section would have stood or fell. It has also been suggested that the eastern shear wall was too small.
Unfortunately in one of Jeff Ostroff's recent videos he points out a group of rebar sticking out of the garage floor slab next to the "H" that looks like column remnants where there should have been none at garage level. Odd? Yes, very. However the logical conclusion is that the beam immediately above that location (1st floor and up) disconnected from the H transfer beam, came straight down, and penetrated the garage floor slab. The workers removing debris probably would have left it in rather than pull it out and risk more damage to the very slab that they were working on. (I'm wondering if they may have even poured cement in to it to help stabilize things, like the various testing holes they dug and then filled back in). But instead, he insists that they built another column in the garage at the last minute. Permits or GTFO :P
Of course, the question could be easily answered by someone who could get up close to it and actually see what happened, rather than looking at a potato-cam photo.
There was a similar theory about a now infamous "column M11.1" that should have been visible in the Tiktok pre-collapse garage video taken from next door. If you go through all of the objects that may have been in the garage (floor, columns, possibly a couple of cars, bad lighting) and on the pool deck right above it (deck itself, a bunch of planters filled with tall plants, a white round deck table and a few green deck chairs) it is certainly possible that there is just stuff blocking the view of the column - but instead he insisted that it had "fallen". Perhaps it did, who knows, in the video all we can see is a pitch black spot. When the rest of the building fell on it, it probably sheered it off and/or pulverized the column so we may never know.
But again, it is hardly even important unless one is looking at that as a possible "trigger" spot. After the pool deck collapse it would have been supporting nothing - just like the other columns sticking through. With all of the focus on that one column, it overlooks the fact that there was a horizontal lateral support beam on the garage ceiling between that column and the building support column (not normally visible from that angle) that almost certainly would have fallen in order for the planter material to fall as it did (probably under collapsed pool deck slab and planter remains so still not visible). It was that beam and two others like it that seem to have done in the building support columns.
But, as it is, this "fact" that this column was missing even made it in to the legal filing about the vibrations during construction of the new building next door.
(Score: 1, Touché) by Anonymous Coward on Saturday November 20 2021, @09:25PM
Nobody wanted to pay to maintain the building. Our entire government is falling down for the exact same reason. Which half of the country will remain standing? And will it need to be knocked down too?
(Score: 0) by Anonymous Coward on Monday November 22 2021, @05:09AM
Can't we just agree, like Presidential candidate Jeb Bush when talking about school shootings, that shit happens and get over it?
(Score: 0) by Anonymous Coward on Monday November 22 2021, @09:02AM
no degree, just internet and comfy armchair.
what is in a name ... "surfside".
i looked on sat photo and saw there's a lagoon at the back.
also, it seems to be landfill underground. 500 years ago there was no permanent land above seelevel there.
with hurricans pushing water (ocean) regularly and lagoon in the back, the water in the " back" (lagoon) prolly drained into ocean thru area under building ...
building are built so a giant could pick them up and move them around "as one piece" (with limitations).
pools are a energy, chemical and money drain. if they leak and no thought was put for dealing with draining leaks, salt and/or other chemicals not good for concret and rebar don't drain but pool and start a big party for "team corrosion".
lagoon draining water, water pressure from ocean (hurrican, salty mist), chemical laced water from " maybe leaking pool" prolly undermined some foundation to compromise the certificate "that a giant could pick up the building" integrity .... *shrug*.
scary place to build and live in ... sry