The Miami Collapse [Updated!]

Will not be overly long on this, but have been saddened and fascinated with the Champlain collapse in Miami since news of it first surfaced. Here is a New York Times report. Here is an absolutely harrowing tick tock, with video and photos, from The Washington Post. Seriously, make sure to look at the WaPo piece.

The Champlain South building just pancaked. The World Trade Center buildings had the instigation of jet fuel laced missiles flying into them, this did not. Nor did the Hard Rock collapse in New Orleans, which was under construction and never certified nor occupied. This is different. Only four are reported dead as of this posting, but nearly 160 missing, so the number will definitely grow. Rescue efforts well underway, but it seems bleak.

This Champlain building was the “south” one. There is a “north” one that is seemingly siamesed and of the same design, materials and construct. The local mayor wants to evacuate it. And, that would be no problem, frankly I’d already be gone if I lived there.

But the problem with water in Miami and the Florida coast has been foreshadowed for a very long time. The sea level is rising. The ground is wet. This building was, apparently, built to code only 40 years ago and was in the process of “repairs”. But would “repairs” have stopped this? Am inclined to think no. So, then, what is the status of all the other buildings in that line of the relevant water table?

Also, pools belong in the ground, not on decks.

Since it is “Infrastructure Week” yet again, maybe some thought ought be given to water tables, both growing in places like Florida, and shrinking in places like Arizona and California.

UPDATE: Am going to add in this comment from Pete, and I think it exactly right:

“I am not a structural engineer nor a geologist, but I have lived in Southeast FL all of my 70 years and witnessed the ever higher and closer together high rises along the coast and even more inland Miami since the 70s on.

I think it is important to know the geology of the Florida peninsula:

Forget the underlying Florida Platform which would be bedrock that most might think of. It’s 10,000 feet down and you aren’t drilling down that far and filling up a hole that deep with concrete and rebar. So you drill into the karst limestone layer for which the record drill depth is a recent 170+ feet for a newer 57 story building in Miami adjacent to Biscayne Bay.

Limestone is the sinkhole gift that keeps on giving especially in central Florida – just ask Jim White,

Furthermore, in a pique of insanity places like Surfside as well as the Las Olas area of Ft. Lauderdale – about 40 miles North – are actually partially soft fill reclaimed wetlands. Ft. Lauderdale circa the 1920s That’s right – the build site is a lot of man made land.

I would not and cannot say that is relevant here, but in Las Olas settlement and the rising sea level coming UP through the porous land causes constant water main failure, sewage line failure, and flooding. Flooding due to water being forced UP is a major increasing problem in Southern Miami Beach.

It is reported that Champlain Towers, built in 1981, had been “sinking” mm per year since the 1990s.

As in most major disasters it’s not just one error but a series of errors and missed opportunities to avert the disaster that get missed – or ignored.”

257 replies
  1. Anomalous Cowherd says:

    I first realized that America had become a third-world nation back in 2008 when the Baxter heparin fiasco made the news. Our infrastructure is woefully underfunded, we responded poorly to a major pandemic, a mob attempted to disrupt the peaceful transfer of power, and now a shocking collapse of a residential building with an unknown number of dead. Does that sound like a well-functioning nation state to you?

  2. harpie says:


    “Though some of this damage is minor, most of the concrete deterioration needs to be repaired in a timely fashion,” the consultant, Frank Morabito, wrote about damage near the base of the structure as part of his October 2018 report on the 40-year-old building in Surfside, Fla. He gave no indication that the structure was at risk of collapse, though he noted that the needed repairs would be aimed at “maintaining the structural integrity” of the building and its 136 units.

    Also NYT:

    At the ground level of the complex, vehicles can drive in next to a pool deck where residents would lounge in the sun. Mr. Morabito in 2018 said that the waterproofing below the pool deck and entrance drive was failing, “causing major structural damage to the concrete structural slab below these areas.”

    • bmaz says:

      Right? That said, language like that is commonly in building evaluations. One of my questions is, how many similar reports are there there? How many “should” there be??

      • harpie says:

        How can the NYT assert that he “gave no indication”?

        Evidently, the required review after 40 years was enacted because of a previous building collapse in 1974.

      • harpie says:

        Evidently, the required review after 40 years was enacted because of previous building collapse in 1974.

      • jc says:

        Scan in all high rise Florida building reports like the 40 year report this building had, then key-word search for certain terms – then hold your breath!

        DeSantis’s challenge is damage control, not damage to the actual buildings, damage to Florida’s real estate market. He needs a quick report providing assurance this was a completely unique situation. The building collapse wasn’t his fault but the pressure to cover up any systemic problems with the safety of hundreds of aging high rise Florida condos is palpable. There probably aren’t any cost effective ways to restore the safety of these buildings and many might be total write-offs.

        Anonymous calls from engineers whose dry engineering language reports have been ignored are probably coming. Maybe AFTER DeSantis sounds the all clear, then he can send the state police seaching for whistl-blowers

        • joel fisher says:

          Agree with everything except that the cat is out of the bag real-estate wise. Who would buy a condo in the Miami Beach area now? Maybe the whole of South Florida. If deSantis can prevent–or reverse–this apocalyptic crash he’s operating at a bamboozling skill level that makes Trump look like an amateur. But he ain’t.

      • jc says:

        scan in all relevant building inspection reports, then run a key word search for warning terms and see what spits out, I think a lot, it’s never just one cockroach

    • harpie says:

      Continuing directly:

      The report added that “failure to replace the waterproofing in the near future will cause the extent of the concrete deterioration to expand exponentially.” The problem, he said, was that the waterproofing was laid on a concrete slab that was flat, not sloped in a way that would allow water to run off, an issue he called a “major error” in the original design. The replacement would be “extremely expensive,” he warned, and cause a major disturbance to residents.

      Near future…Exponentially…major error…

        • harpie says:

          Yes, 2018…it evidently took this amount of time to be ready to “just about to get started on it”.

      • bmaz says:

        I do not know anywhere near enough on this specific case to say. But, as far as I can tell, the “report” was by a consultant reporting to the condo board. Keep in mind that such “consultants” are often looking to CYA as to any conditions found, but just as importantly are often engineers looking to get the contract to do said repairs. It is not always a clear scene.

        • Nell Lancaster says:

          Helpful perspective on what such reports can mean, thanks. But this report makes one clear factual assertion that seems crucially relevant and verifiable in the near future – the waterproofing was laid on flat rather than drainable sloped surface, a design flaw of the building. Is it also the case in the matching apartment tower? Something to look into immediately, while residents evacuate.

        • bmaz says:

          It is really early, but the Surfside mayor sure looked to me to be indicating that the sister building was effectively identical. Which, if so, is pretty scary.

        • Robert I says:

          The report also noted that there were sizable cracks and exposed rebar.

          If, as seems likely, there was no significant remedial action, considerable further deterioration is likely to have happened since since then.

        • earlofhuntingdon says:

          Exposed rebar is a wick. It sucks up water and moist salt air, leading to rapid deterioration.

        • bbleh says:

          This kind of situation is toxic in the tropics. If the rebar is not properly moisture-resistant from the start, then as the water oxidizes it, it swells, and it literally splits the surrounding concrete from the inside. And if the rebar is not properly treated from the start, then it’s unlikely the concrete is, which allows the moisture to seep in, and there it goes.

          Noting of course that it’s still unclear to what extent this kind of process caused, or contributed to, what appears to be a major structural column failure. The land apparently has been subsiding for some time, which may have caused a load shift. There may have been some sudden catastrophic event like a sinkhole. Or some combination of all the above.

        • CCM says:

          Rebar in concrete eventually rusts, expands and loses structural strength in all climates. The number of structures at risk in our country is too numerous to count.

        • CCM says:

          See below comments re: epoxy coated rebar. Uncoated in huge numbers of structures a slow moving disaster.

        • Lex says:

          Consultant here. I’m reading our native language as learned from lawyers and the cost of liability one way or the other. The translation for this is: “it’s fucked, you’re fucked but I need to make sure that I don’t get fucked.”

        • Leoghann says:

          Exactly. I thought that consultant did a very good job of couching his findings in a professional way. He hit all the pertinent points, and threw the people who hired him (the condo board) under the bus very gently. He also didn’t endorse immediate, emergency work. –You guys can get onto avoiding this potential major structural damage at your own speed.–

          The town inspector who said a few months ago that he saw no problems, on the other hand, is burnt toast.

      • OmAli says:

        I watched while our concrete guy checked the slope of our porches and driveway to make certain any water would drain away from the structure.

        Hell, before we ever made camp we made sure that the slope was away from our tent.

      • OmAli says:

        I watched while our concrete guy checked the slope of our porches and driveway to make certain any water would drain away from the structure.

        Unbelievable, something like that being overlooked….

        Hell, before we ever made camp we made sure that the slope was away from our tent.

    • El Ingeniero says:

      For the last home home inspection I had done, the guy said a door “may need replacement or repair.” In truth, it was completely rotted out and the rot had spread from the door to the wall and the sub-floor.

  3. P J Evans says:

    Pool decks are usually the concrete slabs around pools – but I have seen pools on upper floors, generally in buildings with high prices for residences, and I wouldn’t live in one of those structures. And how the #$%^&*!! the architect missed things like grading for slope away from the building, and heavy-duty waterproofing of everything around the pools and the garage entrance, is beyond me.

    Also it took 17 HOURS for DeSantis to get to a disaster declaration. His border thing was apparently much more important. (The WH was ready within two hours of the collapse.)

    • Hika says:

      I don’t know the details here, but plenty of times the architect’s plans are not exactly what gets built. Many a builder is over fond of short cuts and ‘savings’. No doubt there’ll be an inquiry and various parties will do their best to blame anyone else but themselves.

      • Artemesia says:

        The horrific Kansas City collapse of an elevated walkway onto a crowd which killed 114 is an example of the difference between design and execution. The architectural design called for independent anchoring of the two walkways to bear the load; the guy who built it just hung one from the other with a relatively flimsy bolt– it was an utterly predictable disaster if you knew how it was built not how it was designed. The only surprise is that it didn’t happen sooner.

    • bmaz says:

      Yeah, we have a “cool deck” around our pool, which is firmly in the ground. I do not want 20,000-25,000 gallons of water on a “pool deck” above our house. And that is just a medium residential pool, not one for a big swanky condo complex. Put that thing in the ground!

      • Artemesia says:

        our last place had a pool deck on top of the garage; I am feeling better about the new place not having a pool after seeing this disaster. The garage was pretty physically separate from the building itself and not very tall.

        • vvv says:

          I stayed some years ago at the Emily Morgan Hilton in San Antonio and they have an outdoor pool on like the 12th floor or so at the back of the building- it was a disconcerting place to swim and drink.

        • P J Evans says:

          There’s a hotel in downtown L.A. with a rooftop pool. It had been an office building; we watched them converting it from our 26th-floor window (several floors higher than the pool).

        • posaune says:

          I remember when the Manhattan VA Hospital installed a therapeutic pool some decades after the original building construction. They took the building portion down to the steel, and then redesigned the structure. It was impressive. The web on the beam(s) was about 8′ deep to accommodate the live load. Of course, that building was federal spec, not some FL developer.

        • earlofhuntingdon says:

          Hong Kong has a few notable rooftop pools, too. But that new plastic one in London, suspended between two buildings, is just crazy. The English are normally more sensible. I wonder if it’s the oligarch money, which carries a recklessness with it, or the cloud of chaos BoJo carries with him like Pig-Pen’s cloud of dirt.

    • mass interest says:

      “Also it took 17 HOURS for DeSantis to get to a disaster declaration. His border thing was apparently much more important. (The WH was ready within two hours of the collapse.)”

      Among the various news reports I’ve read, there’s mention of both the socioeconomic (i.e., “middle-class”) status of the inhabitants and ethnic/religious characterizations.

      Gotta wonder if DeSantis’ response would have been more robust had the residents been described as White and wealthy.

  4. earlofhuntingdon says:

    There are a plethora of buildings along the shore and on barrier islands in Miami, each designed to be as close to the shoreline as possible. The foundations are built on limestone – porous as hell – which means it will be saturated and not able to carry the loads it might have done were it not. Sea walls would do nothing to change that.

    Beware the “reporting” designed to create the impressoin that this is a one-off, “who coulda knowed” problem. A lot of these buildings were built in the same era, with similar construction materials and techniques, and on similar foundation material. Developers like cheap-to-build – ask the former guy – and I would be surprised to find anyone in South Florida who has more juice than they do.

  5. rosalind says:

    shortly after moving into my PacNW condo i discovered an area of rot on my balcony near a support beam. this triggered a structural review of the entire 4-story 45-year old building on a hill above the water, subject to regular rain and wind.

    the report boiled down to: the building required a complete structural renovation. we have a very pro-active HOA board that immediately went to work, but pulling all the pieces together on a major project takes time. the design. finding a contractor. putting things out to bid. the financing. the permits. it took about a year and a half to get everything in order, then two years for the full rebuild.

    i cannot begin to fathom how much money & time it would’ve taken to repair that Surfside building, if in fact a repair was even possible. (and how they haven’t evacuated the sister building yet…yikes)

    • P J Evans says:

      The building my mother lived in for the last several years of her life had to have the exterior wall replaced because of water problems – they use plywood with a surface finish, and maybe put lath to cover the seams, but that doesn’t prevent water getting behind the boards. Cheap construction (and easy to build with less-skilled labor), expensive fixes. The townhouses next to my building are like that, and the paint is peeling off the boards. (Looks like the surface finish is molded vinyl.)

  6. Pete T says:

    I am not a structural engineer nor a geologist, but I have lived in Southeast FL all of my 70 years and witnessed the ever higher and closer together high rises along the coast and even more inland Miami since the 70s on.

    I think it is important to know the geology of the Florida peninsula:

    Forget the underlying Florida Platform which would be bedrock that most might think of. It’s 10,000 feet down and you aren’t drilling down that far and filling up a hole that deep with concrete and rebar. So you drill into the karst limestone layer for which the record drill depth is a recent 170+ feet for a newer 57 story building in Miami adjacent to Biscayne Bay.

    Limestone is the sinkhole gift that keeps on giving especially in central Florida – just ask Jim White,

    Furthermore, in a pique of insanity places like Surfside as well as the Las Olas area of Ft. Lauderdale – about 40 miles North – are actually partially soft fill reclaimed wetlands. Ft. Lauderdale circa the 1920s That’s right – the build site is a lot of man made land.

    I would not and cannot say that is relevant here, but in Las Olas settlement and the rising sea level coming UP through the porous land causes constant water main failure, sewage line failure, and flooding. Flooding due to water being forced UP is a major increasing problem in Southern Miami Beach.

    It is reported that Champlain Towers, built in 1981, had been “sinking” mm per year since the 1990s.

    As in most major disasters it’s not just one error but a series of errors and missed opportunities to avert the disaster that get missed – or ignored.

    • earlofhuntingdon says:

      Reclaimed land in large urban areas is likely to pose special problems owing to extreme global heating and a rise in sea level. Large sections of lower Manhattan, for example, are built on landfill, some of it crushed oyster shells – limestone. The Marina District in SFO didn’t exist before the Exposition – a little more than a hundred years ago. Baltimore is vulnerable, as are lakefront cities such as Cleveland, Detroit, and Chicago, which have lakeshore areas built on variable quality landfill.

        • matt fischer says:

          IIRC, the primary problem in the Marina was apartment buildings with soft-stories due to parking spots for cars. The apartments were effectively cantilevered over open areas for the cars below.

        • TooLoose LeTruck says:


          Now that you mention it, I do remember that detail from accounts of the time.

          Years ago, I used to do a fair amount of work on my car… and I learned pretty quickly that if I had the car jacked up and was pulling a wheel, block it up with something strong enough to deal with the weight involved, and if I used a cement block, DON’T set the block under the axle so the walls were horizontal… turn it 90 degrees so the walls were vertical.

          Wooden blocks would be even better.

          At any rate, that issue – the cement block collapsing if it was placed under the axle in the wrong perspective – sounds very much like what you’re describing w/ the buildings that collapsed in the marina district.

      • vvv says:

        FWIW, Chicago seems to have mandated that they put caissons down to the bedrock.

        Here, and even the failed former’s building here, go down 110 feet.

        I recall reading of a structure last year that was down 135′.

        Of course, those are newer high-budget downtown buildings, and I’m sure plenty of older ones are at risk.

        • posaune says:

          Building codes in Hawaii require design for seismic, hurricane wind load and flooding. Not cheap.

        • P J Evans says:

          Aunt and uncle had a house designed and built for them in Malibu, on a hillside with a fine view of the ocean. They said the price they got for their prior house (in a Boston suburb) was enough to cover the thing, with its two geological reports and its heavy-duty foundation (which includes a couple of steel beams driven deep into the ridge). It’s also survived two fires going through the area, both of which were stopped literally in the back yard.

      • Foraker says:

        Not to give anyone the wrong impression, but there’s not that much of Cleveland that is on landfill — the municipal airport (that lots of people would like to see shut down and turned into a park), the Rock Hall, the Science Museum, Browns stadium, and the Port warehouses and docks. The downtown business district is 50′ higher.

    • Su Hall says:

      You nailed it, Pete! I dated a boy in high school whose father was superintendent on large residential complexes. He went over to the St. Augustine area to look at an upcoming project. He turned the job down, however, when he saw the plans for the building’s foundation. He wanted nothing to do with it. That was the mid-seventies, or, roughly 40 years ago.
      Adding to that, lime rock only needs water and pressure to disintegrate.
      There will be more, I’m sad to say.

  7. joel fisher says:

    If the water is coming up from below–either sea level rise or wicking from elevated groundwater– sooner or later the rebar in those slabs is going to rust, the slabs will lose their integrity, and the buildings will fall. In a state where cities such as Miami have line items in their budgets for pumping seawater, rain, or both off of submerged streets, it’s amazing that their public policy excludes elimination of carbon emissions. “Climate change” that’s just commie talk from people people who hate freedom.

  8. Raven Eye says:

    Google Maps has the site marked as “Miami Building Collapse”, and a link:

    Much of the Street View photography along Collins Ave is as recent as January 2021. You can see very striking similarities among many of the condos. I’m sure that reporters are sifting through property records and permits — we’ll likely see some patterns emerge.

    DeSantis will need to come up with a distraction pretty soon to divert attention from his office. If there are patterns in design, engineering, construction, and inspection, that quickly evolves into major financial and social impacts on those municipal entities and he’ll need do get some distance.

    • JC says:

      Florida is all about business so DeSantis will have to put out a happy talk PR fast based on a preliminary assessment that this is a “one of a kind situation”, not true! Builders, realtors and property mgmy companies take care of pols like DeSantis – and he will return the favor

  9. P J Evans says:

    My parents always wondered about the building inspection on the house they bought in the mid-60s. Some of the stuff they found was *definitely* not up to code. They fixed what they could.
    Some of it: no mud sill on the slab floor section (hello, termites!); rafters not notched to fit the sills; joists not spliced on the second floor. And the steam heating system (we still don’t get why that) was installed with the main lines in the attic.

    • Tracy Lynn says:

      If you mean home inspections before they bought the place in California, inspectors are only allowed to look at certain things. I learned this from when I bought my condo—we could see things that needed to be fixed that didn’t show up in the inspection report. When I queried the inspector later, he said he was only supposed to look at items like floors for any rot — but not check beneath the flooring to look at subflooring, for example.

      • P J Evans says:

        No, this was during construction – it was a custom-built (for the builder!), and the neighbor had been living there at the time. The house stood out, and still does, for being two stories in an entire neighborhood of ranch-type houses.

        • P J Evans says:

          Also, none of these would have been visible. Some required taking wall paneling off. (Knotty pine – lots of it. And select-grade redwood on part of the exterior front.)

        • Leoghann says:

          “Custom built by the builder for his own family” is a common builders’ sales ploy. They are able to avoid owners’ or buyers’ scrutiny or inspections, and can live in a cheaply-built house with all the bells and whistles for a year or two. Then they move on to the next cheaply-built, ostentatious house, pocketing a considerable profit.

    • Artemesia says:

      Every home we have had has had not up to code stuff that wasn’t caught be inspectors e.g. boards directly on dirt that led eventually to termites, plastic tubing for water to refrigerator laid under granite kitchen floor, pipe’s not properly shielded from cold — I now live in a high rise where Lake Michigan used to be — fingers crossed here.

  10. Dizz says:

    Rescue efforts at collapsed Florida condo slowed by ‘very deep fire’
    A few more interesting bits:

    A “very deep fire” hampered rescue efforts Saturday at the collapsed oceanfront condominium tower near Miami where authorities are racing to recover any survivors beneath a mountain of rubble, officials said. Rescuers were using infrared technology, water and foam to battle the blaze, whose source was unclear. Smoke has been the biggest barrier, Miami-Dade Mayor Daniella Levine Cava said during a news conference. “We’re facing very incredible difficulties with this fire. It’s a very deep fire. It’s extremely difficult to locate the source of the fire,” she said.

    Gregg Schlesinger, a former construction project engineer who is now a lawyer handling construction defect cases, … added that there are frequently “telltale signs” on oceanfront buildings indicating problems structurally largely from saltwater and salty air intrusion.
    “This is a wakeup call for folks on the beach. Investigate and repair. This should be done every five years,” Schlesinger added. “The scary portion is the other buildings. You think this is unique? No.”

    • Pete T says:

      In an interview yesterday, the Surfside Mayor speculated that the deep fire may stem from generator fuel source topped off in prep for hurricane season. Unclear what the fuel source is (gasoline, diesel, propane, etc). Gasoline from crushed cars.

      One would think that the smoke could be analyzed.

      Mayor also noted the prevailing wind – east to west – but in often reverse during t-storms has tended to keep the pile largely clear of smoke. It’s the Western neighborhood – ehere he lives – that’s is getting most of the smoke.

      Still few masks seen on the pile yesterday.

      • Lex says:

        It would be hard to fingerprint from smoke or fumes. Generator would be diesel or even fuel oil. But everything plastic burning would make it hard to distinguish between liquid hydrocarbons.

  11. Lawnboy says:

    “Rust never sleeps” Neil Young.

    There are countless bridges in Canada that are being replaced, repaired or modified because of road salt usage. Epoxy coated re-bar is the norm now when these structures are rebuilt because cement is porous, and moisture moves in to degrade any metal.

    As fate would have it, I have 30 years of metals-lab , analytic instrumentation experience, calibrating same.
    Most of lab time was taken in fault analysis for our customers .

    Thoughts are with the families, so sad.

  12. Frank Anon says:

    I certainly hope there is an aggressive investigation. I have a number of friends in the Orthodox community, and to a man they believe the building was targeted by Hamas as a retribution for the most recent Gaza war. Much of this is based on the video circulating that shows the facade falling in ways that are reminiscent of some of the Gaza, and the building had a very robust Jewish population. While it is always expected that people will make allowances for the unthinkable, and try to give a context that makes more sense than someone screwed up in the 80’s and beyond, I fear that this may be a fertile opportunity for the Governor in a community he clearly covets. The faster that a clear reason is proven is not soon enough, but the potential cratering of a red, red hot market scares DeSantis more than anything. If hinting a terror connection befell Champlain Towers, rather than the (probable) notion that 40 years of waterfront condos may have equal danger and may then have to be evacuated or subject to extensive repair keeps real estate sales humming, along with being perceived as a protector of the Jewish community, I wouldn’t put it past him if the investigation drags.

  13. Bobby Gladd says:

    I pulled up and zoomed in on an angled view aerial photo posted on USA today which clearly shows the pancake collapse. Starting at ground level and going up using the balcony railings remains, I can count close to the 12 stories. I seriously doubt there are any survivors in that mess. It is simply terrible.

  14. Alan says:

    If just one concrete column holding up the building in the garage underneath fails, it can lead to a domino effect that takes down the whole building. IMO, we’re likely to find that was the problem, not sea water or subsiding ground. I’m not saying those aren’t potential problems, but allowing a supporting column to disintegrate will cause major problems every time, and it’s gross negligence to do so, since this should have been relatively easy identify and temporarily reinforce and repair…

      • Alan says:

        Age doesn’t matter. Reenforced concrete can last hundreds of years, as long as water doesn’t get inside and rust out the inner steel reenforcement.

    • posaune says:

      I’m wondering about the original structural design Factor of Safety (FOS). In NYC, FOS design must allow for the failure of two structural columns without compromising the overall structure stability. Horrible to think that this building may have collapsed with the failure of one column.

  15. observiter says:

    I heard an “expert” mention that sand added to concrete can strengthen concrete, but that if sea sand (with its high chloride content) is used it could cause reinforced steel to be vulnerable to corrosion. (For details, do a search — a lot of articles on this.)

    • dude says:

      “Sand” is actually a description of stone aggregate size–it can be made of many things. But in general, sand is commonly used in cement and it, and larger aggregates, are common to concrete. I doubt if the sand involved would be an issue.

      • bmaz says:

        They are both made of aggregate, which may be generically called “sand” depending on the size. Don’t screw this up around a structural engineer, they will skewer you. Even though “cement” is a component of “concrete”, they are quite separate things.

      • earlofhuntingdon says:

        “Cement” is heated and pulverized stone, generally limestone. It’s a binder that holds together “aggregate” or crushed stone of various diameters.

        “Concrete” is a mixture of cement and, commonly, small – sand – and larger aggregate – often 3/4 inch stone. Its performance and durability depend on the ratio of the three, which has been finely worked out by engineers, depending on its intended purpose. Chemicals are sometimes added to make the mix more plastic or workable, to allow it to set at colder temperatures or in less time, and for other purposes. Cement is the most expensive component and the one most manipulated by unsavory players.

        Concrete is commonly reinforced (to increase its load-bearing capacity) with steel mesh, bars, or cable-under-tension. As scribe has noted, its design, placement within the concrete, and proper fastening into a connected system are essential to its ability to evenly spread the load – or not.

        • matt fischer says:

          Rebar (reinforcing bars), or another type of steel reinforcement, is not so much about being able “to evenly spread the load.” Steel reinforcement of concrete provides resistance to tension (pulling stress). Unreinforced concrete is strong in compression (pushing stress) but very weak in tension. Steel such as rebar is very strong in tension. The resulting composite structure, known as reinforced concrete, is thus able to resist significant tensile and compressive forces.

        • earlofhuntingdon says:

          The comment was already teetering on being too technical. To your point, a poured reinforced concrete basement wall is better at bearing the compression load from the house above it than a less expensive cement block wall. Its greater value, as you point out, is in resisting the side load from, say, hydraulic pressure from poorly drained soil around the foundation.

          But reinforcement is used for both compression and tension. Residential concrete slab foundations in Texas, for example, are commonly reinforced with tensioned cables. Residential concrete driveways and aprons are commonly reinforced with rebar. Roadways and airport runways use even more sophisticated reinforcement systems.

        • bmaz says:

          See, also, a “weir wall” as an underground barrier to prevent water encroachment in water susceptible areas.

        • matt fischer says:

          Yes, you are absolutely correct that reinforcement increases concrete’s load-bearing capacity. I wanted to clarify that the “magic” behind that ability is to be found in the reinforcement’s strength in tension.

        • P J Evans says:

          Sidewalks are likely to be reinforced with heavy-gauge wire mesh. (The 6-inch kind makes good tomato cages.)

        • earlofhuntingdon says:

          Yep, but mesh is a pill to keep suspended during a pour – essential to keep it from laying flat on the bottom of the slab, where it does no good. Quarter inch rebar is often used on larger sidewalk projects, tied to and suspended at the joins on small blocks.

        • Alan says:

          The steel reenforcement also helps resist shear and buckling. Those are the two most likely modes of failure in a concrete column.

        • posaune says:

          OT a bit:
          I remember a William Safire column in which he debates the term “cement mixer truck” — asserting that it should be known as a “concrete mixer.” (One of the few things he was right about.)

  16. sls642 says:

    As someone who was born in Miami and have lived in Florida all my life, I have witnessed the constant threats that unrestrained growth and money have inflicted on our citizens. From salt water intrusion to wetland destruction, this has been going on for decades. It has just gotten worse over time with sea level rise, coastal armoring, wetland destruction, dredging and filling, toxic algae blooms, the list goes on.

    The Florida Legislature attempted to address some of the problems we were facing decades ago through the enactment of a Growth Management Law, coastal construction setback standards, environmental land purchases and others. But this willingness to deal with difficult issues and powerful special interest didn’t last long. There was a time when Florida had a number of elected officials who cared about the state, not just money and power. And yes, it was a combination of Republicans and Democrats. But this all changed over time and money won. Basically what we are seeing today will eventually destroy us unless we begin to elect people who are willing to recognize the gravity of the problem and protect our citizens.

    Here is a question that is major yet I haven’t seen discussed in the context of climate change and everything that goes with it. When the most expensive real estate in a state like Florida becomes a total loss, who pays for it? Hurricane Andrew demonstrated that even insurance carriers with huge amounts of money could face claims they couldn’t pay. What we are facing now makes Andrew look not that catastrophic after all. I can’t even imagine the amount of losses that will be suffered and no one, not even the feds, has the money for that. It is simply staggering. And I am only considering Florida, not other coastal states.

    I can’t say the collapse of this condo was that much of a surprise. Building codes in Dade are on paper, fairly strict. However, It is a place that has a long history of politicians and bureaucrats with their hands out.

    Plus, we have a property tax system that rewards maximum development (no matter where) over public safety and quality of life issues. Now with the arrival of climate change, it is past time to rethink how we view property rights and the interests of society.

    • Mary McCurnin says:

      When we get to the point of massive and unfixable damage to coastlines, it won’t matter if insurance companies can meet their financial responsibilities. We are or will be doomed.

    • jdmckay says:

      Here is a question that is major yet I haven’t seen discussed in the context of climate change and everything that goes with it.

      This is the million dollar question AFAIC. bmaz made passing reference to this:

      (…) maybe some thought ought be given to water tables, both growing in places like Florida, and shrinking in places like Arizona and California.

      Things are actually much more dire, comprehensive then that. With years of extreme drought, not just water tables but largest reservoirs throughout the west are down to record lows, some 20-30% of “normal”. Rivers are drying up, several critical northwest salmon runs are believed likely to disappear this year.

      Significant hydro-electric generation reduced and, some of large dams now, non-existent.

      Agriculture production is massively down, some of most productive areas are completely fallow. Ranchers are selling and/or slaughtering there remaining herds.

      The long & short: there simply is not enough water to go around anymore. And the western drought conditions are forecast to continue indefinitely.

      This is all man-made (C02) climate change. There is no solution but to go green yesterday, but there is little movement or will. Some models now are showing we are at or even past the “tipping point”, that this eco change has been in-alterably changed. We are facing problems humanity has never seen before.

      When the most expensive real estate in a state like Florida becomes a total loss, who pays for it? Hurricane Andrew demonstrated that even insurance carriers with huge amounts of money could face claims they couldn’t pay.

      Sure, good question. No answer I think. When you said “climate change and everything that goes with it”, that everything dwarfs the localized problems being discussed here in Florida. People are going to want to be made “whole”, and for the overwhelming majority there will not be resources to do that. Arguing “culture wars” and all this other non-sense is, AFAIC, just further evidence US society has become somewhere beyond dysfunctional.

      If and/or until people wake up and realize that their localized consequences are not unique, are connected to all these other climate events and become willing to make dealing with this humanity’s “Manhattan Project”, basically… we’re fucked,

      In Vietnam where I’ve spent most of last 2 1/2 years, same problem with different manifestation: too much water!!! Massive increase in Monsoon rainfall that has wiped out many villages in central provinces. Where I still have my house in SF east bay, a lot of smart people I’ve know for decades are openly questioning the viability of (literally) long term survivability there because of lack of water.

  17. dude says:

    The building is reported to be reinforced concrete and the damage appears to me to resemble cast-in-place concrete. The steel rebar can corrode easily if exposed anywhere and in a salt-water or salt-air environment corrosion will accelerate faster. The rust expands and pushes against the concrete causing it to spall off or crack. It also reduces the working cross-section of the steel. Rusting from even the slightest exposure to moisture will migrate into more concealed areas deeper within the concrete causing more spalling, cracking–weakening–along the way. This also reduces the solid working cross-section of the concrete. When the steel is no longer firmly bonded (embedded) in the concrete because of these things, the load which was once shared by the combined strength of steel and concrete begins to skew toward one or the other. Steel is good in tension and concrete is good in compression. In good design, purely vertical loads are resisted well by concrete (compression) and steel resists well forces perpendicular to that (in spans, it bends, but wants to spring back—something concrete alone can’t do very well). At the intersection of columns and beams, the rebar is threaded horizontally and vertically to help resist loads in both directions. If the corrosion weakened the connection at these intersections, and the balance between tension and compression forces skews too far one way or the other, so you get movement and failure.

    All that said, failing piles seem an equally plausible candidate to me. I will be interested in the geotechnical assessment.

  18. scribe says:

    I’m not going to speculate on the cause of the failure here. It is, most likely, a combination of things that came together in one bad moment.

    I will speak a bit from my own experience, as a B.S. Civ. E., former geotechnical field engineer (that’s soils and foundations – building and fixing), and having done more than a bit of construction litigation after that. I also grew up in an area of karst geology and know a bit about sinkholes and associated failures.

    1. A failure of the bedrock (sinkhole/collapse) under the building might, or might not, have compromised the foundation such that the building collapsed. Assuming there was one, how deep below the building was any collapse? The deeper, the less it would affect the building because the foundation loads spread out with increasing depth. Assuming there was one, how big was it (in plan view, i.e., from above)? The more area, the more it would affect the building.

    2. Just because something is built on filled land (i.e., soil/rock brought in and placed to raise or adjust the surface topography) does not mean it’s inherently unstable, weak or prone to fail. Filled land is distinct from “landfill”, i.e., a garbage dump. You can, in fact, successfully and safely build on landfill if you do it right, “doing it right” being a topic beyond the scope of this comment. Yes, parts of lower Manhattan, SF, and who knows where else are built on filled land. If either you clean out the swamp muck first (it’s usually a swamp that someone wants to convert to office space) or bury it under lots and lots of clean fill (boulders down to sand – with a nice mix of sizes so all the voids are filled in) or you run pilings deep into the fill (pilings usually are not held in place by resting their end on something solid way down but rather stay put because of friction applied to their sides by the soil they’re driven into), you can get a solid base upon which to build the building. It costs money, time, engineering skill and compliance with sound practice both in design and execution.

    3. One of the things my professors stressed was KISS – keep it simple, stupid – because the guys doing the actual work are … stupid/illiterate, and/or care in direct proportion to the amount they’re paid, DGAS, or no comprende. Or some combination. It takes little to no reading ability to swing a shovel, wire rebar, pour concrete. Frankly, for a lot of those jobs intelligence is a handicap – they are insanely boring.

    So these guys are not the brightest bulbs and in more ways than you can count. I was sharing a drink last night with a friend who is a VP of a construction company and was previously a construction superintendent. He related about a project he supervised some years back, to rehabilitate the cafeteria in a county jail in a southern state where he formerly lived. All his workers – painters, electricians, laborers, plumbers, supervisors – had to be cleared in advance to work inside the jail. The county was not going to let the inmates go while they re-did the cafeteria. He related how, as the workers entered he watched his crews having some workers sent the one way and some the other. It turned out he lost between half and 2/3 of his crews because the ones lost were sieved out by the jail because they had outstanding warrants for child support, traffic tickets, you name it. And, of course, the jailers would not let these new inmates work. These workers were so stupid they went reported for work at a jail despite having outstanding warrants.

    I have little doubt the work on this building was average at best. Which is to say it passed inspection.

    4. I cannot tell whether the rebar – a lot of it pulled right out of the concrete and is hanging on the sides of the building – was properly installed and wired in or welded in, in the first place. Nor can I tell whether there was enough rebar, properly placed, or anything else about it. That’s something forensic engineers will spend no small amount of time poring over. Nor can I tell whether the rebar was epoxy-coated or uncoated. My recollection is that epoxy-coated rebar was just coming into wide use in the industry in the early to mid-80s. Epoxy-coated rebar tends to resist corrosion far better than uncoated. Uncoated rebar (and any reinforcing steel) will expand when it corrodes/rusts. That will crack the concrete around it. And things only go downhill from there.

    But we do not know whether any of that took place. It will take a lot of forensic engineering to determine that.

    5. Concrete is another place where the work could have been good, bad, or indifferent. One feels safe in assuming the concrete work itself was up to spec – obvious problems would have been visible no later than the time the forms came off (40 years ago). What we don’t (and, given the devastation probably never will) know is the degree to which the concrete may have deteriorated since completion. The short version is that concrete and salt water, salt spray and salt air do not get along. The chloride ion (from salt) attacks and weakens concrete, turning it into crumbles. It’s beyond my knowledge (and probably anyone’s at this point in time) to determine whether any of the concrete was so affected, where it was, how critical it was (if any was affected) and if it had anything to do with the collapse. Something to watch for but, again, forensic engineering has to take place first.

    6. Corner-cutting. On every project, corners are cut. Oftentimes, it’s something that facilitates quicker construction and results in no less safety.

    Right now, the overwhelming likelihood is that there are about 150-160 dead people in the remains of that building. Their bodies need to be recovered, their lives mourned, and the forensics take place to determine why what happened, happened. I am inclined to doubt there will be enough insurance coverage to pay decent amounts to their survivors, even after dragging in every conceivable potential defendant. The people who were not in the collapsed area will need new housing (and the opportunity to get their stuff out, itself a touchy operation). Their homes are worthless now. Same for the people in the adjoining twin building.

      • Alan says:

        Agreed, cause epoxy is expensive. It should be used wherever water can be an issue, but I doubt this concrete was designed to withstand prolonged water exposure, which is why the drainage was so important.

        • scribe says:

          It was not necessarily the added expense of epoxied rebar that would be at issue. I am uncertain about the exact date but epoxied rebar was first becoming widely used in the market at about the time this building was built, or possibly even after it was built.

          The visual appearance of the rebar now, hanging down post-collapse will tell us little if anything about whether there was epoxy. It likely would have been stripped off as the concrete pulled off the rebar. It’d only be visible on close inspection. I’m more interested in how the rebar was connected inside the pancaked decks. There are long, long tendons hanging on the side of the building – possibly as long as the decks were wide – and I’m wondering what they were connected to inside those pancaked decks and how they were connected.

        • bmaz says:

          The extra cost is still significant. Better question was whether it was even easily available back then. I will bet the answer is no.

        • scribe says:

          I don’t think the epoxy-coated rebar was readily available until the mid-80s, 4 or 5 years after this was built. I’m going to have to check.

        • bmaz says:

          That sounds about right from what I’ve seen today. Structural engineer friend did make a good point that you don’t need it once a few feet off the ground, for that regular is okay.

    • dude says:

      I especially agree with your point #2. I did not have much experience with piles before moving toward the coast of my home state. Almost all the buildings on the university campus where I work are on piles. And the variety of pile designs and spacings to maximize the friction is quite fascinating too.

    • earlofhuntingdon says:

      Nice work. That filled land can be made stable for construction purposes does not mean it is in practice. Geology will be a factor, and contractor skill, but it’s probably most affected by item six. As you say, cost-cutting can affect all aspects of construction.

      Reminds me of an old saw attributed to contractors responding to consumer demands for ever lower costs. “You can build it at my price, and you’ll know where the cost savings come from. Force me to build it for yours, and only I’ll know where the cost savings come from.” But that shouldn’t apply nearly as much in commercial construction.

      • scribe says:

        “. That filled land can be made stable for construction purposes does not mean it is in practice.”

        Not so.

        When I would arrive on a site I’d go have a meeting with the site superintendent and – at least – the leader of the heavy equipment crews. I had a standard spiel I’d give them:

        “Hi, my name is [name]. I’m the soils engineer from [firm name]. I’m here to help you make money.

        “You know and I know the only way you make money in this business is by doing the work right, the first time. There are specs and drawings you already have. If the work isn’t done to spec I won’t sign off on it and you won’t get the letter from my bosses back in the office saying it was done to spec and then you wont get paid and you’ll have to do it over. Let’s all work together on this. If you have questions or think there’s a better or cheaper way to give the customer an acceptable product, let’s talk about it. I can run it back to the office and let them make the call on whether to approve it. Any questions?”

        I worked alongside professionals and I worked alongside guys who made Tony Soprano and Joe Pants’ Ralphie look like pikers. The one time a contractor chased me around a site, him on a D6 and me on foot, just for fun. Another time I saw a developer used for bumper pool by three walking calzones from the City who’d come to collect for truck rental. That developer was so crooked the bank made him videotape the entire project so they could review it to see work was actually being done before approving the next progress payment.

        Probably the most honest guy I worked with was a mason contractor. The one time, there was a dispute among a couple of the other trades. One trade guy said he was connected and brought in a soldier from the big city to mediate. When the soldier arrived on the site the first thing he did was blanch, come over to the mason contractor, genuflect, kiss his pinky ring and apologize, saying “I’m sorry. I didn’t know you were here. If I had known, I wouldn’t have come. I meant you no disrespect.” The mason accepted his apology, the soldier left the site, and the disputing trades sorted things out without need for a mediator.

        The only way to make a living and a career in the construction industry – or any industry, for that matter – is to preserve your integrity. The way to preserve your integrity in the construction industry is to not get involved in the currency of favors. Do not accept an invitation to one of those TVs that fell off the truck. “Thank you, but no, I already have one I like”. Do not cut the guy a break on the number of loads that came in, or the compaction numbers or anything. You can’t win in that world. Even the crooked contractors had to respect that. Plus, I held the keys to the bank and they and I knew it.

        • earlofhuntingdon says:

          I wonder which guys Donald Trump and his ilk employed, or his peers in South Korea, Africa and the Middle East. I agree with your observation about the masons. Most respected guys on the job site. Also the most affected by employment-related injury – lungs and knees especially.

        • Geoguy says:

          Thank you for your last paragraph: “The only way to make a living and a career in the construction industry – or any industry, for that matter – is to preserve your integrity. The way to preserve your integrity in the construction industry is to not get involved in the currency of favors…” I am a geotech and have been at it for over 30 years. (I could never be a lawyer as I am just not that smart, just a ground pounder with a state sponsered, state university education.)

          Our firm provides soils and foundation investigation reports hoping to provide on-site soils engineering services during construction. The only way to play it it to be faithful to the design and not cut corners. I’ve seen corrupt companies go out of business and people go to prison for cheating.

          I read this post after there were well over 100 comments so I don’t have anything to add except to note that this tragedy was caused by a cascade of events from the ground up (no pun intended.) Many buildings I work on have a design life of only about 40 years but many owners are reluctant to or won’t properly maintain them. joel fisher’s comment at 7:44 today is a good one. There could be many similar buildings in the same state of decay awaiting the same fate.

    • P J Evans says:

      CA had to replace a lot of concrete highway paving some years back, because the sand was beach sand and hadn’t been thoroughly washed before going into the mix. Salt isn’t good there, either.

      • punaise says:

        A lot of the older (pre-WWII) homes on the west side of San Francisco (the Avenues, aka the Sunset and Richmond Districts) have foundations whose concrete mix included widely available beach sand. I have seen (and caused to be replaced) lots of deteriorated footings out there in the course of remodels (spalling, crumbling).

        • P J Evans says:

          I grew up east of SF. When the neighborhood guys decided to put up concrete block walls, they used local aggregate, as in they took a pickup over to one of the gravel pits and bought a load – over and over. They built the forms for the blocks, and my father did special ones for the section of curved wall. The cap was dyed to match the houses and poured in long sections.
          The walls still look good, more than 60 years later. (And yes, they did the foundations underneath – the soil is mostly clay with aggregate.)

      • earlofhuntingdon says:

        The ocean vs. washed sand issue comes up dramatically in the final episode of season six of Endeavour.

        • vvv says:

          It was also part of the plot of some noir novel or another that I’ve been wracking my wrecked brain to recall …

        • Yancy says:

          Yes! I thought about that episode while reading the comments, too.

          Here’s a question though:
          What do we know about the construction and stability of China’s man-made islands? (This may have been addressed in comments appearing below the Earl’s. I was just so excited to feel confident enough to comment on here.)

          Regarding the high-rise residential development in St. Augustine, I’d love to know if it was ever built and where. I grew up summering on the barrier island there, Anastasia Island, on Crescent Beach. St. Augustine Beach imposed really strict height requirements on new construction. They were fighting in court with the Hampton Inn hotel over their water slide exceeding the height limits. (I don’t think there were any/many condos over 4 stories high on the island.)

    • OmAli says:

      The families of the missing must be in agony. if I was a praying person, my prayer would be that for the victims, the end was swift and painless.

    • ChuckD says:

      A great treatise on concrete reinforcement construction.
      Many moons ago in a previous century I was an iron worker in a small rebar fabrication shop. Four guys including the owner, a licensed civil engineer and a real straight shooter. He would bid on jobs and bring back the spoils for us to make happen. I would later go on to an Assoc. in CivEng, and then architecture school.
      We did work for the State which required epoxy-coated bars. We’d typically receive them off a truck or rail car, cut and bend to what the drawings indicated, and deliver. But between the fabrication and delivery we had to go over all the bars with cans of said epoxy patching up areas where the paint had scraped off in handling, or any open cuts. This was a total shit-show. This in no way waterproofed them and I expect most of them developed rust over time. There was simply too much painting that needed to be done, and the bars would suffer yet more scraping and abrasion in the bundling delivery and installation.
      That was around 1986ish. Maybe things have changed since, but what we were trying to do was like patching a canoe made of chicken wire.

  19. Rugger9 says:

    There are several mentions above about the costs. Some things to keep in mind, especially about builders in the period is that cutting corners for cost reasons was fairly common (so, no epoxied rebar) and it’s not clear who lives in those towers. I do know as a member of another HOA that many of my colleagues are (ahem) skinflints who would argue that nothing really needed to be done right now about an expensive proposition like addressing foundation problems. As noted above, “getting around to it” after three years just might be warp speed given what I’ve seen when serious money is involved. Double that reluctance if these were largely retirees and snowbirds. As another example, my mother lived in a community in Nevada County where the board tried to defer some key infrastructure issue (it might have been the dam) in the hopes of making it someone else’s problem after they sold their places. At least, that what it looked like to me.

    San Francisco’s Marina District is landfill, which in earthquakes liquifies as we saw in 1989. Much of the business district is actually built atop old hulks dating to the Gold Rush as ships were abandoned to go to the gold fields. Florida is different, in that not only is there flow from the sea but also freshwater down the peninsula which is why sinkholes can form in Winter Haven (that one ate a Mercedes dealership in the ’70s) which is near Orlando.

    • earlofhuntingdon says:

      Needless to say, organic matter – like timbers from sailing ships abandoned in SFO Bay as their passengers and crew joined the 1849 Gold Rush – does not generally make good land fill. It decays and collapses in volume, allowing foundations to shift.

      For some reason, it reminds me that the Central Pacific’s Big Four (Leland Stanford, Mark Hopkins, Charles Crocker, and Collis Huntingdon) made their earlier money from the Gold Rush, but not by prospecting for gold. They sold supplies: $50 for a shovel to desperate would be miners on their way up to the fields, and $0.50 to buy it back when they came down, tapped out. Wash, rinse, repeat.

        • bmaz says:

          Hey now, if Studebaker made wheelbarrows, said wheelbarrows may still be around somewhere. One of the reasons Studebaker failed is that they did not sufficiently build things to fail and be replaced. Never quite got the planned obsolescence thing.

        • elcajon64 says:

          Studebaker built coaches and wagons for fifty years prior to their first car in 1902. They went on to build cars for over sixty years. It would be hard to name another company that made the transition from horse-drawn vehicles to automobiles as successfully.

        • bmaz says:

          See, this is why this is the best blog. A building in Miami collapses, and amid excellent discussion of that, a Studebaker discussion also ensues. There are a few people here, including Marcy, that have been to my house and seen the pictures, but my family once owned a Studebaker (later Chevrolet) dealership.

          They were incredible cars. The old planned obsolescence line was simplistic, but not totally wrong.

          The funny thing is, for being remembered as big, boxy and frumpy, Studebaker had some of the best styling and design around. Much of it (the Avanti is still an all time classic) by the great Ray Loewy, who also designed a whole lot of other insanely cool stuff, including Coke machines and super cool trains. Oh yeah, and the Air Force One livery.

        • reasonable rob says:

          We still have the Studebaker wheelbarrow races here at the `El Dorado County fair (Old Hangtown, but that’s another discussion).

          Studebaker Hawk was a comic character in Odds Bodkins.

        • bmaz says:

          Heh, I do not have a wheelbarrow, but now very much want a Studebaker one. Just looked on EBay, but did not find one.

        • Leoghann says:

          My paternal grandfather never owned any cars but Studebakers, his first being from the early teens. His job at the Standard Oil refinery kept him flush during the Depression, and my grandmother became known for hauling various neighbors, friends, and church acquaintances to needful errands in a succession of Studebaker sedans. He passed in 1955, but I have fond memories of trips with him in his 1947 Champion business coupe, on Southeast Texas country roads, honking as he approached unmarked intersections at full speed. He also passed his Studebaker preference on to all four of his sons.

        • earlofhuntingdon says:

          Like William Morse and Thomas Edison, Levi Strauss was a great organizer and marketer of others’ ideas. Using copper rivets to reinforce the seams of denim jeans was the idea of one of his customers for cloth, a tailor in Reno named Jacob W. Davis. They eventually partnered and made history.

    • matt fischer says:

      Downtown San Francisco’s 58-story Millennium Tower was built on sand with 60-90 feet deep foundation piles. Since its completion in 2018 one of its corners has sunk more than 18 inches, and the building leans 14 inches from vertical. In order to remedy the situation, 52 new piles extending 250 feet to bedrock, will be added at an estimated cost of $100,000,000.

      • matt fischer says:

        * Open to residents in 2009. As of 2018, the sinking was measured at 18 inches with a lean of 14 inches.

      • P J Evans says:

        And I wonder what that corner was resting on, that the pilings didn’t hold up.

        This is why so many of downtown L.A.’s highrises are concentrated north of 5th on the hill: bedrock is closer in that area than farther south and east.

        • matt fischer says:

          It’s a highly complex situation with significant adjacent construction and lots of finger pointing. For example, construction of the nearby, more recently completed, Transbay Terminal has been implicated in spite of the fact the sinking was reported prior to the start of Transbay Transit Center construction.

        • TooLoose LeTruck says:

          I’ve been waiting for someone to bring that one up…

          I live in the Bay Area and remember quite well when that story made the front page of the Chron…

          From what I recall, there were a lot of really expensive apartments in that building… the residents sued the builders and the builders in turn sued the people doing the work on the Transbay Terminal…

          I was amazed anyone would keep living in the building once they learned the building had settled eighteen inches.

        • matt fischer says:

          Yes, pretty much everyone has sued everyone. There are quite a few high-profile residents in the luxury condos that occupy most of the building. But good luck trying to sell one of those condos at the moment.

        • TooLoose LeTruck says:


          Yup… good luck on that one…

          Any idea if anyone is even still in the building in the moment?

          Given the inevitability of another major earthquake happening, I’m not sure I’d ever choose to live in a building like that… I remember being up in the BofA tower back in the mid-eighties for a meeting w/ a lawyer and feeling the building swaying ever so slightly in a strong wind…

          I couldn’t imagine being up there in a major earthquake.

        • matt fischer says:

          Oh yes, the building remains occupied. In spite of its issues the building is considered safe to occupy.

          Buildings that tall will sway. That’s normal and, believe it or not, generally safe. It’s what comes with (tempting the gods by) building that high.

        • Alan says:

          Buildings need to meet both strength and stiffness requirements. The stiffness requirement is so that the building doesn’t sway (and with wooden flooring, so the floors don’t bounce). The stiffness requirement is only for the comfort of the occupants, not for safety, and is much harder to meet in a tall building, which is why a certain amount of sway is allowed.

        • P J Evans says:

          Worked in a highrise in downtown L.A. – the highest I ever worked on was the 27th of 50 floors. I was on 26 during the San Simeon earthquake, and it swayed nicely. (“I want instant-acting Dramamine. Doesn’t have to last long, but it has to work really, really fast.”) Also, while working around the 10th floor (which is like 130 feet above street level), during severe winds, I could hear the frame creaking. Didn’t feel it, but it was audible.

    • Christenson says:

      HOA members in condos are, in my experience of one condo with 6 units in a Midwestern city, indeed skinflints even about small stuff like being prepared to lose a furnace or keeping the place nicely painted, even when the condo units were expensive and they pretty obviously have the relatively small amounts of money.

  20. MattyG says:

    We are an office of architects in NY – not structural engineers or geotech so not experts by any means. But as we all watched the video Friday morning in stunned horror, I would say everyone muttered basically the same thing; foundation failure. Massive foundation failure. You couldn’t demolish the building any faster. What a gut wrenching tragedy – horrible.

    For what it’s worth, and at this point nothing, it looked to us as if a major structural element somewhere in foundation gave way, suddenly. Maybe a footing on which a column rested could no longer support it’s load, or a subgrade footing/column buckled or sank dramtically. Immediately we thought the subsoil may have been undermined. I felt sure loud noises must have been audible only hours or a day prior to collapse, and large visible cracks unique to this event must have appeared at the pressure point shortly before. Alas, not enough time or in a visible enough area for these signs to literally scare people out of the building.

    Again, we’re not experts, and it may well have been a pancake effect from top down as some observers have suggested. But our 10-second gut judgement was it was more than salt/steel/concrete deterioration to above grade construction that lead to failure, but foundation related – a subsoil event or compound deterioration effects in the foundation.

    One thing is certain. Unless the disaster can be traced back to a design flaw or construction defect entirely unique to this building, it’s the beginning of a new era. One of far more frequent and aggressive mandated inspections of existing structures, and an industry wide reappraisal of the methods of construction and margins of safety in stuctural design on barrier islands and similar topography.

    • bmaz says:

      Excellent comment. It appears clearly starting from below, not above. Exactly why I so strongly suggested the WaPo tick tock. The collapse sure seems to start from the ground. But once underway, well it gets bad fast.

      I am no engineer of any kind, but have represented significant contractors, thus how I got schooled on the difference between cement and concrete, and how there are gradations of everything aggregate. Still so early on this nightmare, but likely a lot of factors contributed. Given the location, and history lately in the greater Miami area (and this was literally on the beach) it sure seems to be ominous. The ground is the foundation. If it is infirm…..

      • MattyG says:

        The complete sequence of events is unclear since the video begins a few moments after collapse has begun. I really hope there is more tape. For now the epicenter appears to be on the eastern edge of the central mass that went down – it’s pulling everthing down with it. The oceanside block stood longer, and the western edge of the central area hung on a bit as the center went.

        What appears to be two TVs that blink off as the oceanside portion goes down are heartbreaking.

        • OmAli says:

          I just listened on twitter to an NPR interview with a woman who escaped the collapse. Apparently her unit and one other were the only ones that did not shear off, along with the rest of that portion of the building. It was a sensitive, but still harrowing, listen. Just heartbreaking, and what still haunts me is her grief and guilt at leaving her beloved cat behind when she fled. I hope against hope that somehow a crew could safely reach her unit and rescue that cat…

    • scribe says:

      Absolutely it was foundation failure. But that was the last thing before all those floors pancaked. The big question is what was it that led to the foundation failing.

      As to Studebakers … we had one when I was a kid. One of the last ones of the last year. It got obsolescent fast – 100k and it was done. I still love that open S hood ornament. They didn’t just make their money on wheelbarrows – they built Conestoga wagons for transcontinental travelers.

      OTOH, I was behind one of their pickups on the highway a couple weeks ago, perking along in traffic at about 70. Nice, bright red, beautifully restored but not hot-rodded. The thing about late Studebakers was their power was GM, so parts were (and are) available.

      • P J Evans says:

        My grandfather had a sporty 2-door Studebaker, pale green IIRC. (Granny didn’t drive. At all. A horse and buggy or wagon she could manage, but cars, nope.)

    • Rocco Polocco says:

      “I felt sure loud noises must have been audible only hours or a day prior to collapse”

      An article I read yesterday had one survivor mention a loud thunder or crack noise around 3am the morning (22 hours) before, & a son whose mother is missing said it woke her up as well.

  21. matt fischer says:

    It has been reported that the building was making enough creaking noises the day before the collapse to wake at least one resident. This is a very important safety reminder that if your building is speaking, please be sure to listen.

    • Alan says:

      This is the part they didn’t get to in time…


      • Rugger9 says:

        I’m not sure shoring would have helped if the foundation went.

        Again, we’ll support those who are in sorrow now.

        • P J Evans says:

          They’ve updated the building requirements in L.A. on soft structures, and a lot of apt buildings had to reinforce their ground floors. (Earthquakes are really good for finding structural weaknesses.)

        • matt fischer says:

          It’s the same in San Francisco. Soft-story buildings throughout the city have been mandated to perform seismic upgrades, including the building in which I live.

          It’s a really bad idea to have stiff floors above a relatively flimsy ground floor, especially in areas prone to earthquakes. But that’s what exists in many mixed-use buildings with retail on the ground floor and residential units above.

        • P J Evans says:

          The ones I’ve seen with retail ground floors are fairly new – not more than 15 years, mostly less – and the retail is apt-size spaces. I worry more about the parking structure behind them – but I tend to not like parking structures.

  22. Bobby Gladd says:

    Eventual causal culpabilities aside, I am just completely aghast at what looks to be the horrible deaths of many dozens of innocent people without proximate warning.

  23. John Lehman says:

    With global warming, coastal areas around the world are becoming increasingly vulnerable to these kinds of disasters.

    Infrastructure will end up more and more like Netherlands every where. What then will Netherland’s infrastructure become?

  24. jc says:

    There’s never just one cockroach.

    Every Florida coastal high rise over a certain age and height (and there’s a LOT of them) is going to be subjected to a lot of scrutiny and existing reports with fairly innocuous wording re going to set off alarms. Insurers and mortgagors will terminate policies and mortgages based on these reports. I expect some will stop writing policies and stop issuing mortgages on classes of buildings.

    Not only are the condo units in the twin building of the collapsed tower worthless but units in other neighboring buildings are going to be getting major haircuts.

    DeSantis has to manage this situation and he doesn’t seem like someone who would let facts dictate an unfavorable outcome for his career. This pig is going to need a lot of lipstick!

    • Judy says:

      It made me think of the novel New York 2140 by Kim Stanley Robinson. Life after rising oceans claim parts of New York and the corruption that is uncovered.

    • pasha says:

      MacDonald’s Condominium flashed immediately when i saw the pictures, a novel depicting the idiocy of building on barrier islands. never forget that florida is run by and for realtors — and all the corruption that implies

      • TooLoose LeTruck says:


        Ah yes… Florida real estate…

        I had an uncle who was a fair to middling success as an architect in Detroit back in the 60’s… the firm he worked for put up the lights on Tiger Stadium at the time…

        More to the point, he was one of the investors in a group that bought land in Florida for development, I believe for a golf course, that turned out to have quicksand on 96 out of 100 acres, or so I was told at the time…

        Kind of a notorious case in its day…

        • earlofhuntingdon says:

          Great ocean front property! Above water twice a day! The state has long been notorious for its lax real estate sales practices. There are as many jokes about it as there are about lawyers.

    • harpie says:

      Structural engineer discusses concerns raised in 2018 report
      [CNN link above] [My transcript. Please tell me if there are mistakes.]

      Q [Reaction to 2018 report?]
      ML: The first thing that strikes me is the time delay. Three years is a long time to react to something like this. The second thing is, you have to understand that the pool area is outside, it’s not under the building, directly under the building. But the slab is continuous under the building. So, if there was leakage that took place, and it’s very likely it did take place, and damaged structural damage to the building itself, that could have been the proximate cause of the collapse.

      ML: When I look at the film footage, the first thing that struck me, is that the center portion of the building collapses first, and then the outer portion collapses second. Now, the center portion is closest to where the access to the garage is. Now, I would guess that maybe the area under the, the intersection between the garage and the outdoor slab is where the initial collapse occurred.

      ML: I don’t think it effects the search and rescue as much as it effects the portion of the building that’s still standing. I would be very concerned about that portion [] certain that there is no further deterioration in that portion of the building, [] would cause it to itself fail.

      Q: [re: “companion property”, Champlain Towers North, built with same specs, area for concern?]
      ML: Of course. That building certainly needs to have very clear and very detailed inspection, to make certain that there is no deterioration that would cause that particular building to collapse. See, one of the problems is that what is most likely happening, and it’s all speculation, but what is most likely happening is that you get the steel reinforcing in the concrete begins to rust and that pops out the concrete, and that eventually causes a failure.

  25. Jon says:

    This building collapse is an absolute tragedy that should not have happened. It’s far too early to say with certainty precisely what the precipitating issue was. I’ve heard of ground subsidence (NOT the building sinking: two different things entirely; sinkholes; groundwater and flooding; there were known issues of significant concrete spalling and rebar corrosion; and I’ve sen at least accounts of nearby pile-driving, that may have contributed to the failures.

    The video seems to clearly show that the collapse was initiated from the first floor level columns, or below. The near instant and utter failure of the remainder of the structure of those two wings, show a minimal level of engineering. The lack of remnant slab fragments still attached to the elevator core suggest minimal to poor levels of structural construction.

    It is a bedrock principal of structural engineering, that if structures are to age, deform and fall out of serviceability, they should do so in a predictable and progressive manner. There should be no single points of failure, leading to structural collapse. And a structure that should have failed, should do so in a manner that preserves life, regardless of whether the structure is able to later be repaired and brought back into service. Manifestly little of that seems present here, with what seems to be an inevitably large loss of life.

    The matching wing should certainly be evacuated rapidly. The main building structure should immediately undergo a thorough a structural engineering investigation. Nearby buildings should also be inspected, with particular attention to ground conditions, and for foundation and low story structural integrity. Eventually, a thorough structural review will be completed, and inevitably tested in the courts and by insurance companies. As with other, major systems failures, the costs of proper maintenance and the construction efforts needed to provide life safety will prove to be trivial dollars, compared to the ultimate costs. BP tried to save a million dollars on a blowout preventer (and a few other corners cut), and wound up creating a billion dollar problem for us and the Gulf of Mexico.

  26. harpie says:

    From NPR, this morning:
    7:57 AM · Jun 27, 2021

    Good Morning! We have exclusive new information on the #SurfsideBuildingCollapse on @NPRWeekend. A survivor tells us at a board meeting before the collapse, a city official told residents the building was ‘safe’. @Npr’s @BrianMannADK has reviewed the minutes and has a report. [THREAD] [LINKS]

    • harpie says:

      Surfside Official Told Residents Their Building Was Safe, Despite Engineer’s Warning
      June 27, 20211:07 PM

      […] NPR has obtained minutes of a Nov. 2018 [11/15/18] meeting that shows a Surfside town inspector met with residents of the building, and assured them the building was “in very good shape.” NPR learned of the meeting from a resident who was in attendance and who in an interview with Weekend Edition recalled being told that the building was not in danger. […]

      The engineering report was dated Oct. 8, 2018. At a Nov. 15 board meeting of the Champlain Tower South Condominium Association, a building official from the town of Surfside, Ross Prieto, appeared to discuss that report. “Structural engineer report was reviewed by Mr. Prieto,” the meeting minutes say. “It appears the building is in very good shape.” […]

      [Survivor] Susana Alvarez says she was at the November 2018 meeting, and said residents were told the building was safe.

      “We sat there with the town of Surfside,” Alvarez said. “And the town of Surfside said to us that the building was not in bad shape, that the building was not in bad shape. That is what they said, okay?

      “The structural engineer has been around for a while,” Alvarez added. “We took out $15 million dollars to fix that building at his say so. No one ever, ever, ever told us that that building was in such bad shape. No one. No one.”

  27. earlofhuntingdon says:

    To recap the basic narrative, as a building material, concrete goes back millenia. The Romans made great use of it, for example, but their recipe was lost. Its reinvention required rediscovering what materials make good cement and what ratios of water, cement, and aggregate give the desired characteristics. (These have since been minutely catalogued.)

    Its American history starts with and made possible the construction in the 1820s of the Erie Canal. It’s basically a concrete-lined ditch, interspersed with locks, that runs downhill from Lake Erie at Buffalo to the Hudson at Albany. (Until then, it was 20x cheaper to send goods down the Ohio and Mississippi river system to New Orleans, then by sea to NYC, than to transport them across the Alleghenies.)

    Concrete has been called liquid rock. It can be poured into almost any shape, but once cured, it becomes tough and rigid. Structural concrete, however, needs uniform shape, integrity, and reinforcement to add resilience and to evenly transfer loads – both static (the weight of a building), and dynamic (wind and moving water).

    Loads change and impact a small portion of a concrete structure – the surface area of loadbearing walls on a slab or the tire path along a roadway – and must be distributed evenly to the foundation. Uniform shape, a consistent thickness and firm foundation, for example, are essential. Lose one or more of these through damage or decay – holes, rusted rebar – and structural forces will wear away at the weakness, like water worming its way through fissures in Johnstown’s earthen dam, until it fails.

    • pdaly says:

      I remember learning during a tour of the Roman Coliseum that the ancient Romans used volcanic ash as part of their concrete recipe. Somehow the volcanic ash allows the concrete to heal itself.

      This 2017 Nature article states it is due to “a silicate mineral called phillipsite, which is common in volcanic rocks, with crystals of aluminium tobermorite growing from it. Tobermorite seems to have grown from the phillipsite when seawater, which is packed with calcium and silica, washed through the concrete, turning it more alkaline. [snip]. As tobermorite grows, it may strengthen the concrete because its long, plate-like crystals allow the material to flex rather than shatter as it bends.”

    • earlofhuntingdon says:

      I overstated the use of “concrete” in building the Erie Canal. It made greater use of “cement” – incorporated into mortar, and which would cure under water – developed by Canvass White, to bind stones that lined the original 40′ wide by 4′ deep canal.

      Financed by New York state, to the mirth of many establishment types, the novel canal opened the Midwest to trade and the goods that flowed through the canal turned NYC – the transit port for that trade – into an economic powerhouse.

        • earlofhuntingdon says:

          This comment was to correct my mistake of fact, which was not the difference between concrete and cement. It was that concrete was not the principal original lining of the canal. That was cut stone, bonded with mortar made with a novel, American-made hydraulic cement. It was in short supply. It would have been impracticable to use concrete made with it, and too risky. Product quality would have been inconsistent. But the magic was in the cement.

        • Leoghann says:

          That product is known as “hydraulic cement,” and it cures (i.e.: turns into concrete) under water.

    • P J Evans says:

      I remember reading that concrete is essentially a gel. It’s what goes into it that gives it its various properties (including, in some kinds, flexibility).
      But it’s more than 40 years since I took properties of materials as a sophomore.

      • earlofhuntingdon says:

        Just for perspective, he had a hand in a few other things, too. And you wondered why they made you learn all that old crap in school.

    • Eureka says:

      Can’t raise canal locks without talking catfishing, i.e. the pastime where anglers slowly donate chicken livers to the creature-filled depths.

      [Nods to so many contrasts & junctions in historical genesis versus current utility]

  28. harpie says:
    8:45 PM · Jun 26, 2021

    nycsouthpaw has a screenshot of a WSJ photo in this thread.
    If you rotate that photo 180 degrees, you can compare the now remaining pool area to the building plans on page pdf11/84 and 12/84 at this link:

    [100% Bid documents set 4/26/21]
    [IN PROGRESS SET 4/27/21. NOT FOR CONSTRUCTION]—preliminary-review-plans-for-40-year-re-certification.pdf?sfvrsn=9e2a1194_2

    • Kenster42 says:

      I’m trained as an architect and have done a fair amount of work with minor structural foundations and geotechnical in the Miami Beach area. I’ve also reviewed the structural report and the repair plans. I highly recommend folks take a look. Quick takes:

      1. Based on the videos and the available information, including a statement from a maintenance supervisor that used to work in the building, I think the investigation will end up centering around groundwater, tidewater and standing water under and around the parking deck and pool deck. What I think we’re going to find is that saltwater and standing water intrusion just sat around the foundation, slowing eating away at it. Given the 1981 building construction date and the structural engineer’s report, it’s unlikely that anything special was done regarding the concrete mix or the rebar and the SE was clear that there was no sloping away from the foundations at the garage and pool level.
      2. There were reports that the roof maintenance involved both a heavy equipment load and drilling and jackhammering, creating vibration that was felt throughout the building according to some. Possible coincidence, but together these could have been the catalysts that started the catastrophic cascade, unsettling the foundation.
      3. The building did have dewatering pumps, but I suspect that they were not enough or not extensive enough or not properly deployed. Active wellpoint dewatering is rarely done correctly, as it can be expensive both to deploy and operate.
      4. The recommended fixes to the building were $9.1M, with an $80,000 special assessment for a 1 bedroom up to a $300,000 special assessment for a penthouse. That’s a massive cost hit for anyone. I suspect we’re going to find that there was a lot of feet-dragging by everyone on getting this amount approved and getting things in motion. I think the most likely explanation is that folks discussed it for so long that they just decided to work it into the 40 year inspection, which corresponds to the most current plans, which were dated April 2021.

      So, at the end of the day I think it will be a combination of bad construction execution regarding waterproofing, generally primitive construction for the time (no epoxy-coated rebar, no special concrete mixes), and a condo board and residents who were quite reasonably reticent to swallow a $9M price tag for the work. A tragedy and hopefully, like the Kansas City Hyatt incident, a wake up call.

      • earlofhuntingdon says:

        Helluva price tag for the average condo owner, a high percentage of the original purchase price to fix a problem so long in the making. I wonder if the hazards of waiting were adequately spelled out, or rendered in boilerplate – like those nauseating drug commercials – designed to make the average person ignore it.

      • P J Evans says:

        I was reading that people complained about standing water in the garage area as well as around the pool. So residents were aware that there were problems, even if they didn’t know how bad.

        • harpie says:

          Yes. That was [survivor] Susana Alverez, related in the NPR article about the minutes from the residents’ meeting with the Surfside building inspector:

          Alverez said she knew her building had significant maintenance problems. She said there was repeated flooding in the parking garage under the apartments.

          [So it must be in the actual interview, too.
          I haven’t gotten the nerve up to listen to that, yet.]

        • P J Evans says:

          Read it in news story, so probably it’s in there.
          Never been to Florida. It’s dropping down that list.

      • Rayne says:

        I would give this comment a gold star if I could. I will bet the final report on this failure will tick off each of these four items as well as a fifth — an independent analysis will likely find state and local authorities responsible for building code compliance played a key role throughout the building’s life span.

        It took 10 months for a forensic analysis and final report on the Kansas City Hyatt Regency walkway collapse. If only it would take that little time to come to a conclusion in this case for the benefit of other building owners and occupants along shorelines.

        • Leoghann says:

          The walkway collapse investigation was actually pretty straightforward, finding one very specific problem, and a few peripheral ones. This collapse is far more complicated, with problems that piled up for decades.

        • Rayne says:

          I’m fully aware of the simplicity of the KC walkway’s structural failures, much of it resting on inadequate communication and checking during construction. I’ve actually worked on forensic projects like this; perhaps when I gold-starred Kenster’s comment above adding a fifth item to the list of anticipated proximate and ultimate causes I didn’t make adequate note of just how complex each factor is with the fifth one potentially causing the most challenge leading up to the collapse and after since the inherent politics will encourage obstruction and denial, dragging out the analysis.

    • Alan says:

      October 8, 2018
      Structural Field Survey Report

      The condition of the Parking Garage levels was reviewed specifically noting any cracked or spalled concrete members, condition of the concrete slabs and joint sealant conditions. MC was able to identify the presence of previous epoxy injections and patch repairs which were evaluated for their long-term effectiveness. MC’s review of the Parking Garage revealed signs of distress/fatigue as described below:

      J. Abundant cracking and spalling of varying degrees was observed in the concrete columns, beams, and walls. Several sizeable spalls were noted in both the topside of the entrance drive ramp and underside of the pool/entrance drive/planter slabs, which included instances with exposed, deteriorating rebar. Though some of this damage is minor, most of the concrete deterioration needs to be repaired in a timely fashion.

      K. MC visual observations revealed that many of the previous garage concrete repairs are failing resulting in additional concrete cracking, spalling and leaching of calcium carbonate deposits. At the underside of the Entrance/Pool desk where the slab has been epoxy-injected, new cracks were radiating from the originally repairs cracks. …


      Revised Structural Recertification Form

      The pool and jacuzzi are leaking and need to have the plaster removed, all discovered concrete spalling/cracking repaired, and a new plaster finish installed.

      Signs of rebar corrosion was noted in the underside of the 9.5” thick plaza/lobby concrete flat in the area under the pool and planters.

      • harpie says:

        Thank you for adding these excerpts, Alan.
        These two sections, J. on page 7 and and K. on page 8, interested me as well.
        You’ve reproduced J. in full. Below is the rest of section K, following directly:

        [p8] K. […] The installed epoxy is not continuous as observed from the bottom of the slab, which is evidence of poor workmanship performed by the previous contractor. The injection ports were not removed, and the surfaces were not ground smooth at the completion of the injection. Leaching of calcium carbonate deposits in numerous areas has surely caused CTS to pay to repaint numerous cars. This leaching will continue to increase until proper repairs are completed. MC is convinced that the previously installed epoxy injection repairs were ineffective in properly repairing the existing cracked and spalled concrete slabs. MC recommends that the Entrance/Pool deck concrete slabs that are showing distress be removed and replaced in the entirely. [sic] Unfortunately, all of these failed slab areas are under brick pavers, decorative stamped concrete and planters which require completed waterproofing replacement. All repaired concrete slabs located in the parking garage are to be repaired in accordance with the recommendations of ICRI. […]

    • harpie says:

      Other excerpts:

      [p1] Attention: Ms. Maggie Manrara Treasurer […] The goal of our study was to understand and document the extent of structural issues that require repair and/or remediation in the immediate and near future. […] These documents will enable the Condominium Board to adequately assess the overall condition of the building, notify tenants on how they may be affected, and provide a safe and functional infrastructure for the future. […]

      […] [p4] E. Several areas of the entrance drive soffits under the second floor were observed by MC to have deteriorated black plywood. This condition was also observed at several light fixtures in the entrance soffit. MC could not get access into the soffit areas to observe the extent of the deteriorated soffits and support framing as CTS maintenance was too busy to assist us. MC is concerned that mold exists above these soffit areas and the soffit support framing is deteriorated which will require the complete removal and replacement of the entrance suspended soffit. Further investigation into this area is warranted. […]

      […] [p9] MC trusts this initial report will assist the Champlain Towers South Condominium in understanding the required maintenance that is needed to properly maintain this existing residential property. MC is available to further discuss the recommended repair work and how it coincides with the owner’s desires and constraints. We look forward to working with you in maintaining the structural integrity of the Champlain Towers South Condominium. […]

    • harpie says:

      The original structural contract drawings were completed in August 1979
      The original architectural contract drawings were completed in November 1979.

      Does anyone know, or can anyone help me find out WHEN [actual date] the 40 year building inspection was mandated/became law in Miami/Dade?

  29. joel fisher says:

    So go ahead and accuse me of being Captain Obvious but there is nothing very unusual about this building and, therefore, can we not presume seawater to be penetrating the concrete of every structure on Miami Beach at the same pace depending on elevation and mediation measures taken?

    • Alan says:

      It is not at all clear to me that this building collapse had anything to do with seawater or global warming. Looks more like poor drainage of rainwater and/or water leaking from the pool, along with failure to remediate, repair, and maintain.

      With that said, it is clear to me that due to global warming and sea level rise, virtually all of the buildings along the beach in south Florida will eventually be affected by seawater intrusion.

      • joel fisher says:

        It would seem one couldn’t know the status of other buildings in the area without data from inspections becoming available. And by “inspections”, I mean repeated inspections over time reporting the rate of deterioration. If you stop and think about it, this kind of data is not likely to be distributed very widely as the current owners are likely to want to part ways with Surfside asap and they don’t want any more bad news out there floating around. Look for owners to donate their condos to charity: let Uncle Sam take part of the hit.

    • Rayne says:

      Yup, and to varying degrees and at varying levels. Saltwater intrusion from below ground level is very likely given the rise of sea level, the likelihood of spoil or fill with voids used to remediate this wetland before construction; the possibility of saltwater used during construction; salt or chloride contamination in minute and larger cracks in concrete over time due to weathering and storm-related pressure, as well as expansion from within the concrete of any steel reinforcement due to corrosion exacerbated by chlorides, so on.

      Every single building along ocean shoreline is at risk, some more so because of the kind of building technology and codes used at time of construction as well as the level of maintenance the buildings received since construction. I can recall a particular plasticizer used to control concrete and mortar setting speed which was later removed from the market because it accelerated steel reinforcement corrosion. I wish I could recall when it was used/removed.

      Doesn’t help buildings on Florida’s east shoreline that they are facing into the brunt of hurricanes — this collapsed structure must have taken a beating over the years. Historical hurricane tracks over 115-year period via US EPA

      • bmaz says:

        Lol, right this second Mrs. bmaz is literally lounging on a beach in the FL hurricane strike zone. No mention of inclement weather this time.

        • Rayne says:

          Ah, Mrs. bmaz probably won’t be there when Invest 95L turns into something more than a little disturbance.

          My oldest told me yesterday they had vacationed in the tower next door to the collapsed Surfside building. I nearly barfed.

        • bmaz says:

          Heh, she is on the Gulf side, but yeah. And holy shit, I might barf as well. Yikes. Then again, as you likely recall, our daughter was within a few hours of flying into Brussels when the bombings took place. The kids are alright.

        • Rayne says:

          Not the week I will agree with you about the kids. My youngest lost a second friend to a car accident inside 30 months – heartbreaking loss because this young person died as they lived, a hero. Sometimes their guardian angels don’t get the win for earthside.

        • bmaz says:

          Kids do the darnedest things. But you have to believe in them, they are the future, not us. And we were once that stupid and survived!

      • Leoghann says:

        Are you sure you didn’t just turn a grandchild loose with a map and some yellow and orange crayons?

        • Rayne says:

          I’m sure there would have been a cat, a dog, and maybe a bear or bird on that map had the grandkids gone after this with crayons. Their spattering would also have been far less focused along southeast coast.

  30. posaune says:

    A simplified building plan is included in last night’s NYT update.
    I was surprised to see that the collapsed building section(s) contained only ONE elevator and one egress stair. And only ONE elevator and egress stair in the building that remains standing. For a twelve story building. I can’t help but wonder if it had been designed with a robust two-bank elevator and two egress stairs, more would have survived.

    • MattyG says:

      According the 2021 repair drawings Harpie linked a few posts upthread, each floor of the building was serviced by a 2-cab elevator bank in the west wing (street side), and 2 egress stairs, one at each end of a long L-shaped hallway that ran the entire building from the NE corner to the SW. It was a minimalist solution but conventional enough way of providing two means of egress off each floor.

      Keep in mind that it was one building before half of it collapsed, not separate buildings. So the 2 elevators and 2 fire stairs served the whole building. In the collapse the eastern most fire stair was lost, but the 2 elevators and 1 fire stair survived.

      As the elevators were not centrally located, if your unit was on the ocean side it would have been a long hike to and from the elevators… .

      • posaune says:

        Thanks for clarifying. I didn’t describe it very well.
        Did realize that there was only one operable egress stair if they could get to it. Yikes. Horrific.

  31. Pete T says:

    It is mentioned in a few posts above, but Surfside not to mention Miami Beach to the south and various other beach communities to the north including Sunny Isles (Trump properties) are built on barrier islands separated from the mainland by the intra coastal water way.

    I wonder how barrier island geology in general and more specifically in particular to Florida and Surfside and adjacent communities differs from that of the mainland.

    It has gone and goes without saying that barrier islands are natural barriers for several reasons and one of these reasons is not to build high rise condos (much less homes or any other human habitat structure). Even if you can does not mean you should.

    • bmaz says:

      Think the answer was in your first comment! Can’t say about FL, but here you don’t have to drill down very far (like usually a few feet) to get appropriate rock. Not to say that you cannot build safely on the FL coastline, you can. But it should cost a lot. That is why I mentioned the weir wall earlier. There are things that can be done to block off water, and materials that can be used to prevent any damage therefrom. But that is not cheap.

  32. bmaz says:

    CNN interviewing a couple that live in the sister tower a block away. They are not inclined to leave and feel safe enough. I get that it is your home, but jeebus relocate for a bit.

    • Yancy says:

      They might as well pack up and leave. The cost of insuring those condos is going to be untenable.
      After 2004, the year Charlie ripped into Sanibel, (one of my favorite places on earth,) and 3 other hurricanes hit my area of Florida, my homeowners insurance was canceled 3 times, and the premium increases, oh, my lord. I don’t even live near the water!
      Many insurers quit writing policies in the state. I don’t know what’s going to happen now. The state’s insurance fund of last resort can’t possibly accommodate all of these properties.

  33. harpie says:

    Possible Failure Point Emerges in Miami-Area Building Collapse Some engineers looking at the failure of a 13-story condo tower in Florida said the collapse appeared to have begun somewhere near the bottom of the building.
    Published June 27, 2021 Updated June 28, 2021, 5:27 a.m.

    […] One other clue that a problem started at the bottom of the building: Immediately before the collapse, one of the residents saw a hole of sorts opening near the pool.

    Michael Stratton said his wife, Cassie Stratton, who is missing, was on the phone with him and was looking out through the window of her fourth-floor unit when, she told him, the hole appeared. After that, the call cut off. […]

    OY! :-(

    • bmaz says:

      Gonna go out on a limb and say, if I live in the North sister location, am draining the pool immediately.

      • harpie says:

        I would certainly agree in hypothetical mode.
        But in my reality, that IF would not be a possibility.
        I would NEVER [I mean EVER] be living anywhere in Florida to begin with.
        That place is just not for me.
        [I like my seasons, but summer is my least favorite.]

    • harpie says:

      There was nothing unusual about the lobby and pool area at Champlain Towers South condo, which looked clean and well maintained to a commercial pool contractor who visited the building last Tuesday, just 36 hours [6/22/21 AM] before half of the building unexpectedly collapsed. Then, he saw the basement-level garage.

      “There was standing water all over the parking garage,” the contractor, who asked not to be named, told the Miami Herald. He noted cracking concrete and severely corroded rebar under the pool.

      He also took photos, which he shared with the Herald. […]

        • Eureka says:

          Yikes. And all the electrical/physical plant stuff too.

          I feel so troubled for all of those lost souls…

        • Lawnboy says:

          1. Was it a salt water or chlorine pool?
          2. Control room looks like an afterthought IMHO. Where are we putting the pump???Oh ya, this’ll do.
          3. The exposed rebar there is telling. It looks like the damage to the major highway beside the Toronto Sky Dome. Big chunks have been known to buff passing cars that were in the wrong place….an ongoing problem that is costing $$$$$ bigly.
          4. OT : Rebar can be made from electric arc shops (mostly) bc major steel plants cant make money on it and its rough on the rolling mills, goes through like a hack saw on everything it comes in contact with! A saying goes “usually made of melted coat hangers”.

        • Lawnboy says:

          Zooming in, its chlorine, and the injector system (new) will be fed from a concentrated barrel. Note the damage directly above the system of controls.

        • joel fisher says:

          Photos that show a nightmarish lack of maintenance are actually good news. If the building fell because of simply ignoring the basic requirements of maintenance, maybe it’ll be a few more years before the rising seawater rusts out the steel in rest of the Miami Beach high rises and they start dropping.

        • Rayne says:

          I worry HOA and building management will invest in a flurry of weak sauce patch jobs which look better but don’t actually protect the building or occupants.

        • joel fisher says:

          Of course they will. But if new inspections were part of that package, the extra scrutiny might be useful.

  34. harpie says:

    1] Look at page A2C-0.5 [pdf3/84] to find area of consistent deep “standing water” parking space #78, which the pool guy [Miami Herald article] and Susana Alverez [NPR] noted.

    Does it look like there are three rows of columns from the beginning of space #78 [close to entrance ramp] to the last row of columns before the pool. [?]—preliminary-review-plans-for-40-year-re-certification.pdf?sfvrsn=9e2a1194_2

    2] Then look at NYT schematic of the property and count three rows of columns beginning north of the pool towards the building.

    Doesn’t that coincide with the building wall of the center section?

    3] I’m thinking of the “major error” noted in the 2018 report [no slope on pool patio], and the interview with Matthys Levy [also transcribed above somewhere]:

    ML: The first thing that strikes me is the time delay.
    Three years is a long time to react to something like this.

    The second thing is, you have to understand that the pool area is outside, it’s not under the building, directly under the building. But the slab is continuous under the building. So, if there was leakage that took place, and it’s very likely it did take place, and damaged structural damage to the building itself, that could have been the proximate cause of the collapse.

    • harpie says:

      And then there’s this, from the Miami Herald article:

      CBS4’s Jim DeFede interviewed William Espinosa, a Champlain maintenance manager from the late 1990s, who said ocean saltwater would make its way into the underground garage — so much that “pumps never could keep up with it.”

      It’s just one guy’s recollection, but that’s at least twenty two years ago.

      added: One other thing, from the new drawings: are the emergency generators above the entrance ramp?

    • harpie says:

      Also from the Miami Herald article:

      [The pool contractor] said [building staff member] Jose told him they pumped the pool equipment room so frequently that the building had to replace pump motors every two years, but he never mentioned anything about structural damage or cracks in the concrete above.

    • MattyG says:

      A handy way to refer to columns is by their grid coordinates which are printed on most plan sheets. On A2C1.1 letters run along the top of the sheet and numbers along the side.

      For example the east/west 9.1x line forms the south facade of the collapsed wing. That facade runs from the P line to the east, as far as the E and G lines to the west were it tore off along the line of a bearing shear wall that houses the elevators and first stair in the west wind. The L line runs alongside the west edge of the garage ramp.

      Practically the entire site is basement garage – except for a notch in the far SE corner for the pool. The pool sits on the ground by the way – the foundation is at the basement parking level. As the only structure still standing east of the surviving building wing it draws a lot of scrutiny. It shows alarming deterioration but wasn’t itself a direct structural threat to the building I don’t think.

      All columns of the actual building pass through the basement parking area, and that’s where the footings and foundations start.

      I’m concerned with columns L8/9.1 and maybe K8/K9.1. They are part of a group of 18 columns that supported the central area that collapsed first, and are shaded lightly east in portion of that area that seems to go first.

      • harpie says:

        Thank you!
        I think parking space #78, [“standing water”] is within the area you delineate, at the bottom of the entrance ramp, beginning right at the building wall and extending out beneath the patio.

    • harpie says:

      bmaz notes reporting that the Penthouse was “added” after the initial approval [he cites CNN. I found something about it at NY Post referring to WSJ reporting.] An engineer quoted at the Post article says there were revisions submitted [approved?] for the addition.

      The penthouse south facing exterior walls [and roof weight] are located BETWEEN column rows 8 and 9.1, making the [flat?] balcony on that side directly above the area that is thought to have collapsed first. [See p A2C-1.4]

      • bmaz says:

        Well, the plans were sure not approved by the time of the certification process or their ticket would not have been yanked as described. So, they were scrambling and influencing the council. It is an age old story everywhere, but FL has a particularly nasty reputation for such nonsense. And when done after the fact, the usual is a doctored up survey and an after the fact approval “as built”, which is, shall we say, NOT optimal. Especially in a unique site like this. Never seen anything this brazen, but shit happens I guess. Will hazard a guess much more on this will come out over time, but it may take a long time.

        • MattyG says:

          Post approval amendments are pretty common. Buildings often change as they move through the multiple stages of DOB filing, review, approval, and permitting. We have to assume that engineering for the penthouse was satisfactory (for now) – structural engineers are some of the most conservative folks around.

          That said, the sequence in which the central section fell suggests that it was the southern facade that went first – and the penthouse was part of that line. So overall load seems to be a contributing factor. But not necessarily (or likely IMHO) to the failure itself, but to which sections were most susceptible once a failure occurred.

          There are a lot of moving parts and little will be clear, or at least confirmible, until the piles, foundations and what’s left of the lower columns and cross beams have been investigated in detail.

        • bmaz says:

          Sure, supplementals get done routinely. But not by the brazen willy nilly process this has been reported to have been.

        • MattyG says:

          I’m not up to speed on the story. I’ve also heard FL is a kind of ‘wild west’ when it comes to the construction industry and I’m prepared to read crazy that shyte happened.

  35. Mike Stone says:

    The common thread is that the reinforcement tendons in these structures was attached due to corrosion effects (see:

    Ynys-y-Gwas bridge, West Glamorgan, Wales, 1985
    A single-span, precast-segmental structure constructed in 1953 with longitudinal and transverse post-tensioning. Corrosion attacked the under-protected tendons where they crossed the in-situ joints between the segments, leading to sudden collapse.[14]:40

    Scheldt River bridge, Melle, Belgium, 1991
    A three-span prestressed cantilever structure constructed in the 1950s. Inadequate concrete cover in the side abutments resulted in tie-down cable corrosion, leading to a progressive failure of the main bridge span and the death of one person.[15]

    UK Highways Agency, 1992
    Following discovery of tendon corrosion in several bridges in England, the Highways Agency issued a moratorium on the construction of new internally grouted post-tensioned bridges and embarked on a 5-year programme of inspections on its existing post-tensioned bridge stock. The moratorium was lifted in 1996.[16][17]

    Pedestrian bridge, Charlotte Motor Speedway, North Carolina, US, 2000
    A multi-span steel and concrete structure constructed in 1995. An unauthorised chemical was added to the tendon grout to speed construction, leading to corrosion of the prestressing strands and the sudden collapse of one span, injuring many spectators.[18]

    Hammersmith Flyover London, England, 2011
    Sixteen-span prestressed structure constructed in 1961. Corrosion from road de-icing salts was detected in some of the prestressing tendons, necessitating initial closure of the road while additional investigations were done. Subsequent repairs and strengthening using external post-tensioning was carried out and completed in 2015.[19][20]

    Petrulla Viaduct, Sicily, Italy, 2014
    One span of the viaduct collapsed on 7 July due to corrosion of the post-tensioning tendons.
    Genoa bridge collapse, 2018. The Ponte Morandi was a cable-stayed bridge characterised by a prestressed concrete structure for the piers, pylons and deck, very few stays, as few as two per span, and a hybrid system for the stays constructed from steel cables with prestressed concrete shells poured on. The concrete was only prestressed to 10 MPa, resulting in it being prone to cracks and water intrusion, which caused corrosion of the embedded steel.

    Churchill Way flyovers, Liverpool, England
    The flyovers were closed in September 2018 after inspections revealed poor quality concrete, tendon corrosion and signs of structural distress. They were demolished in 2019.[21]

  36. Leoghann says:

    In his original post, bmaz recommended the WaPo coverage. It’s the most exhaustive of the early coverage. The initial videos posted last Friday are impressive. The Miami Herald coverage is also excellent, as their excellent investigative staff has gone to work.

    There are a couple of things I haven’t seen covered. First, as Miami Beach and Surfside are on barrier islands that have been “enhanced” for construction, they do not have exactly the same geology as the landward side of the coast; they are primarily sand deposits that have built up over thousands of years of coastline currents. The entire area suffers from the same type of subsidence as New Orleans and the Mississippi Delta as a whole–the saturated, silty and sandy ground has been sinking just because it can’t handle the weight of all the development. Champlain South had been sinking several millimeters per year, in a geotechnical environment that had been itself sinking. Also, any kind of aquifer, be it ground water or something deeper, not only rises and falls with the volume of its recharge supply. Like any body of water, it has currents. Those can, and do, move sediment, just as they have eroded caves and sinkholes in the karst limestone of the mainland. The terra firma underneath that building may well not be as firm as it was in 1980.

    Second, none of the underlying structural problems were new, nor were they a surprise. A survey of news coverage turns up a number of interviews, with the one by the Herald of the pool contractor who looked at the pool area earlier in the week being the most telling. He not only talks of the damage he saw to the pool’s perimeter wall, which was part of his bidding purview. He says a maintenance man told him that they had to pump the parking garage so often that pumps had to be replaced regularly, and that there was never a time those floors were dry. He also says he told his boss that he thought the pool needed so much more work than the cosmetic repair they were asked to bid that it wasn’t worth it to bid on the job. Cosmetic patch jobs usually placate property owners, but they don’t solve any structural problems. As MattyG pointed out, the pool itself did not collapse. It was actually sitting on the ground. Other reports from the past eight years describe structural cracks in the concrete forming the wall between the pool and the garage, and say the pool and equipment were leaking. This added to the groundwater problem, but not much to the standing water in the parking garage that underlaid the entire building, which was primarily because of the leaks in the pool deck (the large tiled recreation area next to the pool).

    There are reports from as far back as 2013 saying that cracking and spalling concrete columns and walls were observed. Reports from 2015 and 2018 both mentioned previous patching in the structural concrete that had been poorly done, and had actually exacerbated corrosion and deterioration. Surely this did not start in 2015–the place has been cosmetically patched for decades. Residents have complained of standing water and cracks for years. Although almost none understand construction at all, they saw things that were alarming. One owner-occupant was so concerned about cracks in exterior walls that she sued the board in 2015, and was apparently the person who commissioned the engineering report from then. Of the work the board planned to do this year, the only part that was started was work on the roof, primarily to fix cracks between the structural platform of the roof (which held air conditioning and elevator equipment, etc. If there is enough movement to cause the roof to start cracking away from the walls, there’s a serious problem down below. The damage that was done to the concrete columns and their structural steel, sitting on subsiding earth and in a constant pool of corrosive water for 30-40 years, is clearly enough to cause failure. Three decades of cosmetic patches don’t add up to repair. One interview in WaPo today (Tuesday) is of a woman who escaped her apartment just in time. She says some minor movement woke her–she claims it was almost a sixth sense. Thinking it was the breeze, she went to close her sliding door, but it wouldn’t close. Then, she saw a crack beginning in her bedroom wall, two fingers wide. An inner voice told her “run now,” and she did. It’s unfortunate that the woman who told her husband on the phone that the pool deck had just caved in didn’t have the insight to “run now” as soon as she saw it.

    • bmaz says:

      And late last night, CNN reported that the certification was yanked from both North and South Champlain buildings because the developers and contractors just blithely added an extra floor for the penthouse level that was not, I repeat NOT, in the plans approved by the city. That, obviously, would add an extra amount of weight the foundation was not designed for, not to mention placing the structure above regulation for height. In a typical FL story, the developers ran to the city council and got waivers within less that two weeks or so and they were back in business. So this story continues to have about everything.

  37. harpie says:

    [“Less than three”] Months before the building’s collapse, a condo official warned that damage had ‘gotten significantly worse’ in recent years. 6/30/21

    […]“When you can visually see the concrete spalling (cracking), that means that the rebar holding it together is rusting and deteriorating beneath the surface,” Ms. Wodnicki wrote.

    She explained that these signs of growing damage were why the estimated costs of repair had jumped by some 60 percent since that 2018 inspection. “The concrete deterioration is accelerating. The roof situation got much worse,” she wrote, adding, “New problems have been identified.”

    “A lot of this work could have been done or planned for in years gone by,” she wrote in the letter. “But this is where we are now.” […]

    READ THE DOCUMENT [No date shown on this letter]:

  38. David Hoy says:

    The documents that were issued for the upcoming repairs on the tower are available for public review, I have had a brief look at them. They seem more intended for roofing and facade repairs, not heavy duty structural repairs. There are a few typical details for repairing concrete but none of the details are for repairing corroded reinforcing in columns or beams. The repair docs were issued by the same engineer that reviewed the building three years ago. Also the engineer did not identify specific structural repair areas in the drawings. Instead the notes on the drawings request that the contractor identify and mark all unsound areas. Without jumping to conclusions it would be good to know more about what the current repair project was meant to address and what the current engineer was specifically engaged to do.

    • David Hoy says:

      Actually I am wrong, have just learned there is another set of repair drawings, by the same engineer, called “40 year building repair and restoration” that are much more specific about structural areas to be repaired in the tower. My mistake. They are labeled preliminary, not sure how close they were to being implemented.

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