Collapsed Condo

[DBT]

If the building was sound and the failure was caused entirely by ground conditions, you'd expect to also see serious issues with neighboring buildings. I suspect that it's a combination of structural issues and ground conditions.

 

[Trausti]

What unforeseeable building collapse would be compete without engineers/inspectors/owners who knew of the building's lack of structural integrity but decided to do nothing?

 

[Arctish]

Two days before condo collapse, a pool contractor photographed this damage in 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 thought it was waterproofing issues,” the contractor said of the staff member. “I thought to myself, that’s not normal.” He said 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.

The deepest puddle of standing water, according to the contractor, was located around parking spot 78 — an area that building plans show is located directly under the pool deck where in a 2018 inspection report, engineer Frank Morabito had flagged a “major error” in the original design that was allowing water intrusion and causing serious damage to the structural concrete slabs below.

Also: Missing Florida woman was on phone with husband, as building came crumbling down
Cassondra “Cassie” Billedeau-Stratton had heard her building's swimming pool collapse before making the frantic call.

A woman, among those missing from the Champlain Towers South collapse, was on the phone with her husband moments after an outdoor swimming pool caved and then the line went dead.

Rescuers still have not found Cassondra “Cassie” Billedeau-Stratton, 40, who was staying on the fourth floor of the doomed Surfside, Florida condo complex, when she frantically called her husband and described the massive sink hole beneath their fourth-floor unit that had once been the building's swimming pool.

 

[Elixir]

Remember how long it took for the world trade center report to fully explain why the buildings collapsed, and there was video of the planes hitting the building and the fires burning.

If there's a sinkhole under that whole mess, I wonder if that fact would be widely stated. It's not usually good business to panic multimillionaires en masse.
Surfside is basically a sandspit on a limestone base. Neither sand nor limestone are particularly stable. High rise construction should have long since been banned.

 

[Jimmy Higgins]

Man, I thought ODNR well logs could be useless. Florida's well catalog contains almost no useful information at all, making it impossible to figure out what is going on under the ground surface. Based on the location and a healthy amount of ignorance, I'd think bedrock isn't shallow shallow in that area. This seems to back up my hunch.

 

[atrib]

Story in the NY Times reporting that that an engineering inspection report in 2018 had uncovered the presence of significant damage to columns and structural slabs at the basement level- consultant called it "major structural damage", and had recommended rehab measures. Rehab of the structure was apparently in the planning stages when the collapse occurred. The damage was apparently caused by long-term environmental conditions (salt in the air) and a persistent problem with leaking water from a pool located above the basement area that had corroded structural columns and slabs. The condo association knew about the problems and were working on a plan to address it, although they were likely not aware of the threat of imminent collapse. The rehab would involve large assessments on the homeowners ranging up to hundreds of thousands of dollars, which is one reason why progress was apparently slow.

https://www.nytimes.com/live/2021/06/29/us/miami-building-collapse

 

[TV and credit cards]

HOAs of a multi-unit multi-level structures should not be making decisions as to when structural repairs should be made. It should be forced by the county through the engineer’s office and assessed to the homeowners.
They do it here forcing homeowners off septic systems and onto sewer. They are given a ten year payback. They can like it or they can lump it.

 

[Alcoholic Actuary]

Story in the NY Times reporting that that an engineering inspection report in 2018 had uncovered the presence of significant damage to columns and structural slabs at the basement level- consultant called it "major structural damage", and had recommended rehab measures. Rehab of the structure was apparently in the planning stages when the collapse occurred. The damage was apparently caused by long-term environmental conditions (salt in the air) and a persistent problem with leaking water from a pool located above the basement area that had corroded structural columns and slabs. The condo association knew about the problems and were working on a plan to address it, although they were likely not aware of the threat of imminent collapse. The rehab would involve large assessments on the homeowners ranging up to hundreds of thousands of dollars, which is one reason why progress was apparently slow.

https://www.nytimes.com/live/2021/06/29/us/miami-building-collapse

Thanks. I'd upvote this post as the most informative. Here is a version that doesn't require a subscription:

https://www.npr.org/sections/live-updates-miami-area-condo-collapse/2021/06/29/1011280545/letter-from-condo-board-warned-buildings-damage-has-gotten-significantly-worse

Seems like it was structural problems with the subterranean levels of the condo and not earth movement.

aa

 

[atrib]

Story in the NY Times reporting that that an engineering inspection report in 2018 had uncovered the presence of significant damage to columns and structural slabs at the basement level- consultant called it "major structural damage", and had recommended rehab measures. Rehab of the structure was apparently in the planning stages when the collapse occurred. The damage was apparently caused by long-term environmental conditions (salt in the air) and a persistent problem with leaking water from a pool located above the basement area that had corroded structural columns and slabs. The condo association knew about the problems and were working on a plan to address it, although they were likely not aware of the threat of imminent collapse. The rehab would involve large assessments on the homeowners ranging up to hundreds of thousands of dollars, which is one reason why progress was apparently slow.

https://www.nytimes.com/live/2021/06/29/us/miami-building-collapse

Thanks. I'd upvote this post as the most informative. Here is a version that doesn't require a subscription:

https://www.npr.org/sections/live-u...ildings-damage-has-gotten-significantly-worse

Seems like it was structural problems with the subterranean levels of the condo and not earth movement.

aa

Thanks. The NPR site has a link to the actual letter drafted by the condo association president which summarizes the details of the rehab work. Estimated cost of the repairs was about $16M.

 

[atrib]

The New York Times is reporting that Miami-Dade County is conducting emergency audits and/or inspections on 4-storey and higher structures of similar age in the neighborhood that have not yet been re-certified following a 40-year inspection, which is a code requirement. There are 41 structures on that list, of which 24 have previously been deemed "unsafe structures" because they did not comply with all applicable code requirements. The report does not clarify what "unsafe structure" means in this context; my opinion is that it could apply across a wide range of conditions, potentially ranging from malfunctioning elevators or unsafe balconies, to a structure that is on the verge of catastrophic collapse. So far, apparently no major structural concerns have been identified by the county.

 

[Jimmy Higgins]

Regarding repairs, at least half was cosmetic or regarding rails and balconies. It is unclear how much was structurally related.

The New York Times is reporting that Miami-Dade County is conducting emergency audits and/or inspections on 4-storey and higher structures of similar age in the neighborhood that have not yet been re-certified following a 40-year inspection, which is a code requirement. There are 41 structures on that list, of which 24 have previously been deemed "unsafe structures" because they did not comply with all applicable code requirements. The report does not clarify what "unsafe structure" means in this context; my opinion is that it could apply across a wide range of conditions, potentially ranging from malfunctioning elevators or unsafe balconies, to a structure that is on the verge of catastrophic collapse. So far, apparently no major structural concerns have been identified by the county.

I can't imagine a structure that is imminently to collapse would be an "unsafe structure". There would likely need to be another category, liked "condemned" and immediately abandoned. But yes, "unsafe" is likely not to be confused with being labeled as "doomed building" and can refer to anything from structural, electrical, or mechanical. Nomenclature here is crucial and the press can't be trusted to understand it. Those people were too busy getting drunk in college while engineers were busting their butts on homework.

 

[ZiprHead]

Thanks. I'd upvote this post as the most informative. Here is a version that doesn't require a subscription:

As an aside, a little trick I learned is that if you sign up for the NYT daily email blasts, you get several more free page views.

 

[ZiprHead]

VIDEO: Tourist records water pouring from Florida condo, rubble moments before collapse

 

[Jimmy Higgins]

New report unearthed which baffles journalists who know nothing about science of engineering. The report which included terms and language that journalists don't understand, led to frustration as to whether the report was important or not. Desperate, journalists contacted structural engineers across the country to try to figure out what the report meant.

At one point, the report indicated: "yielded some curious results as it pertained to the structural slab’s depth", however, the report didn't explicitly say what they meant by that, though, the report could have elaborated and the journalists were powerless to figure it out. When engineers were unable to answer the question, things just got worse for the journalists who now had to qualify all of their statements.

 

[Jimmy Higgins]

Article from CNN on a tower in San Francisco.

But, since it opened, the hulking blue-gray tower has sunk 18 inches into the soft downtown soil on which it was built -- and it's tilting, according to the Millennium's current engineer, Ronald Hamburger.

And then this thing.

Hamburger, who has monitored the settlements of the Millennium Tower and evaluated their effect on the structure since 2014, told CNN in a statement that the building was designed for earthquake resistance, remains safe and is not at risk of collapse.

"The collapse of the residential building in Surfside ... was tragic, but it is far too early to speculate about what caused that disaster -- and any potential comparisons with Millennium Tower would be reckless and premature," Hamburger said.

This is definitely true, if not a little cold sounding. Comparing the events in Florida with a structure in San Francisco is unwarranted. This is one of those articles that comes up because a journalist equates all engineering issues together in one lump.

That said... 18 inches of settlement?! Does that stat come with an asterisk?

The fix?

A $100 million fix, set to be completed next year, involves the installation of piles into the bedrock of downtown San Francisco beneath the building, according to Millennium spokesman Doug Elmets. The piles will then be tied to the existing foundation, he said.

Beneath the building? Is that journalism-speak? I'd think some sort of structure mat with the piles generally being done in a ring around the building. Installing piles beneath a building almost is never an option, and I would assume micropiles (typically used to underpin underperforming spread footings) wouldn't be used to bear on rock because of the 'micro' part making them not very good at end bearing. Maybe drilled shafts instead? Regardless, sounds like a mess.

I'm really just confused why this thing wasn't put on rock to begin with. After all, if it can settlement that much, it can't possibly be decent material for seismic concerns.

One thing that comes to mind, while bearing on rock will deal with the future settlement issue, it doesn't address the tilting. I assume that will need to add bracing to manage that.

 

[T.G.G. Moogly]

My practicing architect friend states that those buildings go down like dominos if one structural column is compromised. I got the impression there isn't any redundancy built into the structure. I'm very familiar with spalling and seeing rebar exposed and supports crumbling because I live in the rust belt where we apply millions of tons of salt to our roads in the winter. I've seen retaining walls suffer the same fate as salt creeps into the structure.

My amateurish guess is that columns were compromised and could not take movement/subsidence. So was the foundation the problem or the spalling? Likely a combination.

 

[Elixir]

...was the foundation the problem or the spalling? Likely a combination.

Surely both were factors, and probably exacerbated by subsidence or even collapse of the underlying limestone. I don't know much about the engineering that goes into those projects, but it seems intuitive that if the structure was vulnerable due to spalling and foundation issues, even the collapse of a small cavity (such as could be formed in 40 years, even if it was solid when the structure was built) beneath the foundation could have been the trigger.

 

[Jimmy Higgins]

...was the foundation the problem or the spalling? Likely a combination.

Surely both were factors, and probably exacerbated by subsidence or even collapse of the underlying limestone.

Seeing that limestone might be over 100 ft deep (possibly much deeper), I'm guessing limestone issues weren't a problem.

I don't know much about the engineering that goes into those projects, but it seems intuitive that if the structure was vulnerable due to spalling and foundation issues, even the collapse of a small cavity (such as could be formed in 40 years, even if it was solid when the structure was built) beneath the foundation could have been the trigger.

The trouble could more likely have to do with drainage or lack there of (as cited by engineers that inspected the place). Water, especially with salt isn't a friend to structures.

 

[Jimmy Higgins]

My practicing architect friend states that those buildings go down like dominos if one structural column is compromised. I got the impression there isn't any redundancy built into the structure. I'm very familiar with spalling and seeing rebar exposed and supports crumbling because I live in the rust belt where we apply millions of tons of salt to our roads in the winter. I've seen retaining walls suffer the same fate as salt creeps into the structure.

My amateurish guess is that columns were compromised and could not take movement/subsidence. So was the foundation the problem or the spalling? Likely a combination.

There is redundancy, you lose one column, you probably don't have catastrophic issues, but if you have a bunch of columns that are weaker due to weathering, and one fails, while a number of other ones have lost their redundant capacity, this is a big problem. And generally, one element just doesn't go bye-bye without others getting weakened by whatever weakened the initial element.

Foundations can fail spontaneously, but it isn't terribly common, even in Florida, with limestone that has holes in it.

 

[Gospel]

Blah, none of this matters. In about 100 years satellite pictures of that area will look like a pool full of floaties. Throw another 200 years on that to find Florida appearing on US Maps as several Islands with a new state capitol temporarily thumbtacked on Orlando. As an Orlandoian, I hope my descendants manage to hold & sell my house as a multi-million dollar waterfront property at that time.

I see a lot of death in the future for coastal Florida and it's going to be mostly poor folks (like in the case of this collapse). Miami is going to have it worse than any other City. I wonder how many hurricanes it will take for the migration north to begin? I'm guessing the big one. Cat 5 directly hitting Miami with massive casualties and displaced people, Then most of them who evacuated won't return. Maybe stay in Orlando or further north. Rebuilding efforts slowed by lack of interest, and further Job losses bleeding the rest of the population out of the city. Rename it Detriot Florida the floating City, not as attractive as Venice.

This is just my pessimistic & uninformed pissed-off about a building just falling the fuck down side of me venting.