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Miami Beach, Champlain Towers South apartment building collapse, Part 07 90
- Thread starter Seppe
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5
- #61
Retrograde
Structural
Demented said:
None of those photos you posted show any indication whatsoever of failure. You are simply reading things into the photos that are not there to support your preconceptions.
My preconceptions are that tension cables or supporting rebar were damaged in core drilling (related to railing installs, not to concrete testing), as well as heavy rainfall of 2.88" the days leading up to the collapse causing the deck that needed to be replaced back in 2018 to fall below, causing a progressive failure taking the building down because the deck and building were holding hands basically. I could be wrong.Retrograde said:
That pool deck and building held hands better than Jack and Rose.
I'm just simply trying to find any possible bit of any indication of a looming failure because I do find it hard to believe the building would just suddenly give way.
I've been on multiple ocean front projects in South FL from ground breaking to CO over the last 20 years. I now am only involved in the renovation side of these stupid ocean front homes. I don't trust a damn thing in this area especially after witnessing a building inspector and fire marshall pass shit after an expensive dinner at a strip club, but stuff usually gives us a warning before it gives up the ghost.
Precision guess work based on information provided by those of questionable knowledge
Tile is notoriously brittle - individual cracking just about never conclusively proves foundation issues. You really need cracks that span multiple tiles to start suspecting a foundation as opposed to water getting through or kitchenware getting dropped. And that lump near the balcony windows looks like water intrusion getting under some tiles and expanding the mortar. Poor sealing near the sliding doors and/or the balcony isn't sloped. This applies to any house, not just concrete high-rises.
Not sure I saw any issues with #511 main entry doors or entryway closet sliding doors. If we're comparing the straightness of wood post to RC slab, the wood warps first.
The pool deck, on the other hand, was very water logged, not just in photos but from witnesses who spoke of water sloshing around as they walked on the pavers in clear weather.
Not sure I saw any issues with #511 main entry doors or entryway closet sliding doors. If we're comparing the straightness of wood post to RC slab, the wood warps first.
The pool deck, on the other hand, was very water logged, not just in photos but from witnesses who spoke of water sloshing around as they walked on the pavers in clear weather.
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- #66
AutisticBez
Computer
I have a background in food production environments. (Sometimes the only growing industry is food production, have to follow the money).
Anyways, often what occurs is that drainage and the concrete slopes never line up perfectly. Having had cleaned flooring on a daily basis, I could see this issue first hand.
Either the water finds a drain, evaporates in the air, or finds a crack in the concrete to alternative path its way into the slab, columns or foundation.
So one place I worked had a walkway where they had pallets on the ground against the wall. They stacked made up cardboard boxes along the wall. Opposite to this they had fridge entry sliding doors with drains.
So, unfortunately the water pooled under the pallets. And no cleaning was performed unless an audit was due. Where the water was pooling the concrete seemed to sink slowly over time, so the pooling got even worse.
Pooling water on a concrete surface is often ignored, but there is degradation occuring here. Even in a building with temp control this is a problem. Water simply shouldn't be allowed to pool up on concrete without some solution being created. Maybe you grind back the concrete and add more to increase the height?
Anyways, often what occurs is that drainage and the concrete slopes never line up perfectly. Having had cleaned flooring on a daily basis, I could see this issue first hand.
Either the water finds a drain, evaporates in the air, or finds a crack in the concrete to alternative path its way into the slab, columns or foundation.
So one place I worked had a walkway where they had pallets on the ground against the wall. They stacked made up cardboard boxes along the wall. Opposite to this they had fridge entry sliding doors with drains.
So, unfortunately the water pooled under the pallets. And no cleaning was performed unless an audit was due. Where the water was pooling the concrete seemed to sink slowly over time, so the pooling got even worse.
Pooling water on a concrete surface is often ignored, but there is degradation occuring here. Even in a building with temp control this is a problem. Water simply shouldn't be allowed to pool up on concrete without some solution being created. Maybe you grind back the concrete and add more to increase the height?
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- #68
Speaking of construction quality, the Miami-Herald reports that the CTS structural engineer Sergio Breiterman had previously signed off on a project that was not constructed according to plans.
#511 was heavily remodeled, since they completely removed the wall between the kitchen and the multiuse area. If the contractor was sloppy, the floor cracks in the kitchen could simply be from the lack of proper floor prep.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
So this other parking garage project had CMU vehicle barrier walls with an identical detail to the parapet walls at Champlain. Tie columns at 20' on center, with 4 vertical bars at each column. But they found the garage had only 2 vertical bars actually installed. For what it's worth, I've noted all 4 bars visible in some of the parapet wall debris at Champlain. But it does reinforce the general stereotype of shady contractors skimping on details in that time period. Another recent article claimed several thousands of dollars of building materials disappeared from the Champlain site during original construction and that an inside job was suspected at the time. So it's not a stretch to suspect contractors "strategically" omitting rebar here and there where they thought they could get away with it - say at a slab construction joint...
3DSoftwareDev
Computer
Thermopile said:
I disagree. This isn't a wood-framed house. The columns in a concrete structure like this are the primary load-bearing elements, so I doubt the removal of interior unit walls has much of an impact. The only walls that would make a difference would be the few shear walls around the vertical circulation cores.
Interior partitions for this are likely non bearing and have no significant effect on the structure... some codes prescribe a fixed partition load of about 20 psf...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
-Dik
gonefishing2
Aerospace
3DSoftwreDev,
The flat slab is supported by the columns. However, an under nourished slab will deflect. The amount of deflection depends on dead and live loads on the slab. Shifting walls, increased weights of thick set ceramic tile vs original vinyl and shag carpet all affect the load on the slab that gets transferred to columns.
When originally built any weakness in slab to column joints would shift some loads onto partition walls. Say apartment 411 removes some original partition walls, then unit 511 adds 3" worth of hard tile flooring plus heavy built-ins to their floor slab.
What do you think the effect of this will be on 411's ceiling shared slab?
I am sure there are plenty of experts that can explain this better than I can......
Edit: In a perfect world where slab, columns and joints are designed and built properly for the applied loads, there would be no issue in removing non-load bearing walls. But does anyone on this forum think this is the case, after the data that has been presented?
Edit 2: Shifting loads from one under nourished slab to another can shift additional load to column slab joint on lower floor.
The flat slab is supported by the columns. However, an under nourished slab will deflect. The amount of deflection depends on dead and live loads on the slab. Shifting walls, increased weights of thick set ceramic tile vs original vinyl and shag carpet all affect the load on the slab that gets transferred to columns.
When originally built any weakness in slab to column joints would shift some loads onto partition walls. Say apartment 411 removes some original partition walls, then unit 511 adds 3" worth of hard tile flooring plus heavy built-ins to their floor slab.
What do you think the effect of this will be on 411's ceiling shared slab?
I am sure there are plenty of experts that can explain this better than I can......
Edit: In a perfect world where slab, columns and joints are designed and built properly for the applied loads, there would be no issue in removing non-load bearing walls. But does anyone on this forum think this is the case, after the data that has been presented?
Edit 2: Shifting loads from one under nourished slab to another can shift additional load to column slab joint on lower floor.
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- #76
Almost every X11 and X12 unit had the interior partition walls in the kitchen and laundry/electrical room demod.
Don't forget the addition of impact rated windows and glass doors that were to replace the traditional windows and metal accordion shutters.
Precision guess work based on information provided by those of questionable knowledge
Don't forget the addition of impact rated windows and glass doors that were to replace the traditional windows and metal accordion shutters.
Precision guess work based on information provided by those of questionable knowledge
Red Corona
Computer
I'm not really seeing anything much of concern in those 511 pics. Any deviation or cracking in surface materials is likely just due to poor workmanship in laying the new floor imo - you can't see the structural members. The only one for me is that the main doorframe doesn't look rectangular (normally when doors don't fit it's because they've slipped on their hinges, but that doesn't look true here), which if it was properly built in the first place would indicate a parallelogram effect consistent with M columns dropping relative to L. But honestly I'd probably suspect the doorframe not being properly aligned in the first place.
Going back to the punch through columns, in photos from the next day (posted back on threads 2/3), it does look like there's a lot less top rebar than there should be in a lot of those. Some of you posted about that at the time. If that were true in the building as well as the deck then it would make slab detachment a lot easier. But it doesn't seem that was a major factor until the collapse was already under way to me.
Are buildings like this really designed with no redundancy? I think we all agree that the trigger for the main collapse was M9 failing at ground floor level (though there are different reasons offered for what caused that to happen). But surely losing one column shouldn't cause a whole building collapse?
Going back to the punch through columns, in photos from the next day (posted back on threads 2/3), it does look like there's a lot less top rebar than there should be in a lot of those. Some of you posted about that at the time. If that were true in the building as well as the deck then it would make slab detachment a lot easier. But it doesn't seem that was a major factor until the collapse was already under way to me.
Are buildings like this really designed with no redundancy? I think we all agree that the trigger for the main collapse was M9 failing at ground floor level (though there are different reasons offered for what caused that to happen). But surely losing one column shouldn't cause a whole building collapse?
gonefishing2
Aerospace
If you have ever installed a prehung door unit where floor slopes parallel to threshold, and you just set door frame on sloping floor, you will end up with gaps at top like the one pictured. Installer can easily plumb sides with shims, but it difficult to solve un-level floor from one side of jamp to other. And a double door just magnify’s problem.
1972: Breiterman certifies a building that has inadequate rebar and poor waterproofing. It is a building built for the city of Coral Gables, just 8 miles from Surfside.
1976: Newspaper article in local paper points up the failing noted above.
1980: Breiterman is chosen to work on Champlain South, where it appears he again certified a building with inadequate rebar and poor waterproofing.
People in the Surfside building department must have been aware of the earlier problem (newspaper/8 miles). I am surprised their inspectors were not more aggressive in their inspections.
spsalso
1976: Newspaper article in local paper points up the failing noted above.
1980: Breiterman is chosen to work on Champlain South, where it appears he again certified a building with inadequate rebar and poor waterproofing.
People in the Surfside building department must have been aware of the earlier problem (newspaper/8 miles). I am surprised their inspectors were not more aggressive in their inspections.
spsalso
This may be irrelevant to the general hunt but with reference to the 8” condo floor slabs.
Bending rebar: The top and bottom flexural reinforcement provided on the project is not really lacking, perhaps the placement over columns could have been better but there is not an alarming deficiency at all. Slabs generally do not fail in bending anyway.
Punching rebar: It is unclear if any punching shear reinforcing was provided, suffice to say that using today’s codes it would very definitely be required. Some codes even advise on consulting specialist literature for slabs thinner than 8”.
Deflections: A quick run shows elastic (immediate) deflections of these typical 8” floors, with only dead load (self-weight, finishes and limited cmu), are less than ¼ “ for the typical 22’ spans. Theoretically, long-term deflections range from around 1” (grid 8 to 10) to 1 ½ ” (grid 8 to 4).
Fwiw, the dividing walls had reinforcing bars placed at their base (sheet 6) so would have tried to span between columns and behave like beams.
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