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How does the sink rate of a building typically change over time? There are reports this building was sinking 2mm a year back in 1990. Is that kind of sink rate something which would tend to stay constant over time or would it accelerate/decelerate?
Haven’t read the whole thread, but earlier today, they said that the missing included the sister of the First Lady of Paraguay, and her family.
I believe that is why they remove excavated soil and replace it with fill of known qualities.
Work on the roof (moving air conditioning units) was one of the factors that led to the Sampoong department store collapse.
It does kind of look like that, but on closer/reinspection, what I think it shows is that that level of the garage/parking area was elevated around those columns, and whatever was supporting it beneath collapsed (perhaps from the shock of the massive collapse nearby), bending and then exposing bare the rebar around the columns that might have gone into the flooring as the floor fell away.
I think you’re correct. I also see that the entire building isn’t on stilts so if these supports had partially collapsed the building would be out of level, but it’s not.
I don’t think there’s a typical sink rate. It is what it is. I’m not an engineer but the foundation of any building is stabilized as needed with the ground beneath it. If they have to drive pylons to China that’s what they do.
My first thought was a sink hole of such proportion as to shift the soil around it laterally enough to trigger a chain reaction. But I would expect signs of it. I’m sure the engineers are looking at how much material from the collapsed building is above ground.
Here in coastal North Carolina a condo was condemned recently when a contractor performing a more-or-less routine window replacement removed stucco siding and exposed structural elements with significant corrosion. The steel beams were found to have corroded to half their load bearing capacity.
It was a four story building built in 1986 that was condemned in 2017, so just over thirty years old, right on the water, much like the Miami Champlain Towers. The last report back in March of 2021 was that after four years and 3.7 million dollars they were just about ready to start reopening.
I just don’t see this as something appropriate for a federal disaster declaration: small numbers of people losing their housing–and they are not poor and mostly insured.
It isn’t a sinkhole.
Care to enlightened us?
Two things on the emergency declaration:
I think the Federal declaration allows the deployment of Federal resources for rescue and clean up. The residents might be wealthy, but the city of Surfside may not have the resources to deal with that sort of mess. And, also, the rich are called “privileged” for a reason.
This morning’s updates as of 5 am Eastern time zone (posted a bit later due to proofreading and trying to do a little research):
The people looking into WTF happened seem to be focusing on land subsidence issues, which were known as far back as the 1990’s. Now, that isn’t necessarily the cause - it’s not at all unusual for land to shift or sink or otherwise move slightly under a building of any size - but it could be. Or it could be one factor among several leading to this disaster. Keep in mind this building is on a barrier island, it’s not actually on the mainland and has salt water to both the east and west of it. Barrier islands are not exactly stable land to begin with. You can, obviously, build on them - lots of other tall buildings still standing around it - but the terrain has additional complications regarding erosion, the water table, and stability. Typically, foundations are sunk very deep for these buildings but no system is perfect.
A daughter of one of the missing residents said her mother had spoken to her about waking up a day or two before the collapse around 3 or 4 in the morning saying she had heard “creaking” which might have been an indicate of Something Very Wrong… or maybe not, because it’s not unusual for buildings to creak. Hard to say. And even if it was a warning it’s not of much use unless the residents are, first of all, aware of it and secondly know what it means and what to do.
Emergency workers at the sight have reported hearing sounds and “bangs” which might indicate life, but no voices from the rubble.
Florida requires buildings undergo inspection and re-certification when they hit the 40 year mark, and this building was in fact in the midst of that process. As already mentioned on the news, there was “roof work” going on, but “roof work” of all sorts is done on buildings all the time without catastrophic collapses. On the other hand, improper roof loading could be one factor among several.
The building was about to undergo repairs for rusted steel and corroded concrete. So yes, structural deterioration very much could be a factor here (ya think?) but, again, any building that close to the ocean is going to have rust and corrosion issues - that is why thorough inspections and re-certifications are mandated. (remember, the building is actually on a barrier island, lots of salt and water around it). There are buildings far older than Champlain Tower South that aren’t falling down. Fixing rust and corrosion in seaside buildings is its own industry and Florida does a lot of this, so even old buildings remain standing after being hit by hurricanes. In fact, it’s been pointed out that this building has survived multiple very strong hurricanes. The original building structure was sound enough for that, the question is why it failed now, on a night when there weren’t high winds or bad weather or battering by an epic-level storm.
There’s been an architectural expert interviewed on one of the local stations who keeps saying that high rises are engineered (or supposed to be) with internal structures to prevent such catastrophic collapses and limit structural failures to smaller areas. He didn’t provide details and I’m not an engineer of any sort. It does make sense to do something like that. But there’s a gap between “supposed to” and “actually does” that doesn’t always get bridged.
My suspicion - not as an expert, just as a lay person who has a fascination with disasters - is that this will be one of those situations were multiple factors come into play.
They must be recovering bodies from the the rubble - the official death count is up to four now.
At least those families are getting answers as to where their loved ones are and what happened to them, as terrible as that news is.
I just hope the people doing the recovery work stay safe.
There’s a twitter feed showing photos of the missing. It’s heartbreaking.
While a sinkhole is probably a large part of the cause, this cannot be discounted. Built in 1981? Wasn’t that the era that was immortalized in the “Miami Vice” series? Rich people with no brains behind their fast new powdered wealth bullying people to get what they want quickly? Also, that property development and construction is one of the classic tried and true American ways to launder unexplained cash. While a sinkhole may be a large portion of the blame, shoddy construction won’t ever get the spotlight it deserves.
(Imagine the absolute panic and the total cratering of real-estate prices if that was ever listed as a cause? The foreclosure explosion? The inability to justify tax assessments, which would directly impact Florida’s state government and its graft?
That will never happen under governor DeSantis whose policies are always based on solid facts and indisputable science. /s )
PS- Please, nobody start up with the “but Miami Vice wasn’t until 5-6 years later” meme. A writer sees something, a writer writes something, then re-writes it, then pitches it, then re-writes it again, then pitches it again, and then maybe it gets bounced around a year or so before production. Cocaine was a big hit in the late 70s and very early 80s in Miami too.
“Miami Vice” wasn’t live-streamed from some CCTV satellite in 1984
(if there are/were such things).
Forgive my ignorance (I have little experience with civil engineering - I’m mechanical), but I was surprised at all the HVAC/heat pump units that were on the roof; they look no different than what you would find next to homes in the suburbs. Is this a common practice in residential buildings of this size, or am I just seeing air handling components that happen to look like standard home HVAC equipment?
I lived just 3 blocks north from March-April, and there is constant repair/construction going on with most of those ocean side buildings. I have no idea if this is the reason for the collapse, but the locals mentioned that the salt water in the air just degrades things at a very accelerated rate. Even in the very nice place I rented, there were 2 pipe bursts in just 1 month, and the locals said it was a normal occurrence.
Salt water is corrosive. That’s always been a problem for things in/on the ocean. That’s why ships have always required constant maintenance and repairs. Buildings are no different.