Miami Beach, Champlain Towers South apartment building collapse, Part 15 32

[SFCharlie]

A continuation of our discussion of this failure. Best to read the other threads first to avoid rehashing things already discussed.
Miami Beach, Champlain Towers South apartment building collapse
Miami Beach, Champlain Towers South apartment building collapse, Part 02
Miami Beach, Champlain Towers South apartment building collapse, Part 03
Miami Beach, Champlain Towers South apartment building collapse, Part 04
Miami Beach, Champlain Towers South apartment building collapse, Part 05
Miami Beach, Champlain Towers South apartment building collapse, Part 06
Miami Beach, Champlain Towers South apartment building collapse, Part 07
Miami Beach, Champlain Towers South apartment building collapse, Part 08
Miami Beach, Champlain Towers South apartment building collapse, Part 09
Miami Beach, Champlain Towers South apartment building collapse, Part 10
Miami Beach, Champlain Towers South apartment building collapse, Part 11
Miami Beach, Champlain Towers South apartment building collapse, Part 12
Miami Beach, Champlain Towers South apartment building collapse, Part 13
Miami Beach, Champlain Towers South apartment building collapse, Part 14

SF Charlie
Eng-Tips.com Forum Policies

 

[MaudSTL]

If you have any suggestions how the time and motion study could be improved, I would be most appreciative.

Your time and motion study exactly matches my understanding of Ileana Monteagudo’s movements, based on her statements. In her original interview, she said that she was awakened by a “supernatural force.” I think that was the deck collapse at about 1:15 rather than the big crash heard on the first floor at 1:10.

 

[FJBnomics]

Correct me if I am wrong, but I find several things interesting in the design of the perimeter structural wall along the property line of Champlain Towers South, and some can not be maintained due to defective design. As BI said "Designed To Fail".

1 The bulkhead (sheet piles) at the property line is the backside formwork for the 8" perimeter wall. The bulkhead is corrugated, therefore you end up with part of the concrete wall filling this void when pouring the perimeter wall. I assume you have your nominal 8" wall plus concrete filling the corrugations in bulkhead.

2 From the pictures I have seen and the drawings it is not clear whether the patio deck slab pour is capping off the perimeter wall and the bulkhead or did the deck slab stop short of capping off the concreted filled corrugations between the bulkhead and 8" wall shown on plans?

3 Point being, if the deck slab does NOT cap off the bulkhead corrugated area, it leaves a lot of area for water infiltration directly into the concrete corrugate area fill and between the concrete wall and the steel bulkhead.

4 Next you have a concrete block privacy wall sitting on edge of deck slab which does not look to be water proofed, thus it lets water in on top of edge of deck slab, and traps that water inside the voids. It does not appear any water proofing was initially placed under block retaining wall on top of edge of deck slab.

5 Could the Voids were are seeing on the 97 Park side of wall be the gap between the edge of concrete block privacy wall and the corrugate concrete fill area of the sheet piles stopping at top of concrete perimeter wall below, but not serving as the formwork for the edge of deck slab when it was poured after the wall?

6 If so, then when 87 Park excavated up to their newly acquired properly line or the edge of the concrete block wall they replaced the sand that was on top of bulk head corrugated area with gravel fill? Was the bulkhead at the property line or was the 87 Park side of the Concrete block privacy wall the property line? Or was the concrete block wall sitting on mortar fill by mason on top of bulkhead corrugations such that half the block wall was on the deck slab and the other half was covering the bulkhead corrugated fill area? Either way looks like that area was getting lots of water infiltration, and garage pictures reflect that in the rusty pictures taken by one of the owners at her parking spot against that wall.

7 Enter 87 Park Construction and the thermal cycles of the patio deck, I would expect that the gap between the bulkhead and the concrete perimeter garage wall would enlarge at night, and shrink in the day, thus creating more and more opportunities for water entry and stress on the wall structure.

8 Moving down to the Thickened Turned Down Slab Edge Perimeter of the Monolithic Garage Slab Pour. The piles supporting the thickened area of slab at grade are spaced 12' apart, and 5' to 6' in from the edge of the thickened slab. Assuming soil bearing would not support perimeter wall loads directly, the tie into of the thickened slab, footer if you will, is distributing the load of the concrete perimeter wall to the slab. That means the perimeter wall is resting on a thickened slab that is cantilevered 5-6 feet from the piles. Thus seems like any vibrations next door would induce lots of movement along the South perimeter wall foundations? With all the water entry, would it be safe to assume there was soil erosion or displacement under thickened slab?

9 Sorry for the rambling thoughts, but I do not remember seeing any discussion of these issues, and find these issues very interesting. If not interesting to y'all then just punt these ideas.

 

[Nukeman948]

Correct me if I am wrong... "Designed To Fail".

You seem to be asking the right questions but, without as-builts or other information on how these details were dealt with I don't think we can come up with the answers you are looking for.
I would like to add that the concrete block privacy wall was blown down at least once by a hurricane which may point to some initial flaws in the design or construction of this area, was well as the potential for insufficient repair methods contributing to water infiltration and structural degradation long before 87 Park came on the scene.

[sub]This space intentionally left blank. [/sub]​

 

[FJBnomics]

Nukeman, Thanks for the feedback.

Along the lines of thermal cycles and vibrational movement, the area of the patio deck that failed is the longest lightly braced span as others have pointed out. The pool braced one end of South wall, and the building that did not fall braced the other end. The deck that failed was between those two braced ends, which supports lots of movement, deflections, corrosion effects, and of course the pool curb had been raised and rebuilt, so newer concrete in that area of South Wall too.

 

[Optical98]

New Video

Building Integrity

Surfside Condo Claims Engineer Failed to Warn Residents - Lawsuit Analysis Part 5 of 5

https://www.youtube.com/watch?v=FEwQAdSWBsE

 

[FJBnomics]

The image of the Street between Champlain South and 87 Park, prior to Construction of 87 Park, clearly shows there was a concrete walk/curb, on the 87 Park side, up to the privacy wall of Champlain Towers South. It appears Champlain's South perimeter garage wall definitely had better water protection prior to construction of 87 Park than after concrete sidewalk removed and replaced with loose gravel fill.

So removal of that concrete walk/slab would have been very hard to do without damaging the privacy wall.

One would assume the concrete sidewalk sloped away from privacy wall and drained into street.

This clearly supports why there should be building set backs from the property line. Basically both property owners have that right to build right up to the property line it appears.

So where was the actual property line? Was it South side of corrugated sheet pile bulkhead, the middle of bulkhead, or the North side of bulk head?

Then where was privacy wall in relation to property line? Was is South side of wall, or was wall centered on property line?

In my state, private entities can not adverse possess land from a municipality, thus any encroachment by CTS probably did not entitle them to ownership of encroachment. However, in my state such a situation that had stood for years would be grandfathered in, and allowed to remain as long as it was never removed.

In addition, our state does not allow neighbors to shed their runoff on their neighbors. Properties typically have U&D set backs that are allowed drainage paths.

It appears 87 Park clearly was dumping water on their neighbor.

 

[Sym P. le]

... removal of that concrete walk/slab would have been very hard to do without damaging the privacy wall.

No, its not difficult to remove a sidewalk from an adjacent structure.

The gravel strip/boardwalk was a straight forward exchange for the sidewalk/asphalt pavement that it replaced. The gravel free drains through the substrate and has no impact on the adjacent property which hugs the property line.

 

[Jeff Ostroff]

I am working on a video now on the Forbes Ave Frick Park bridge collapse this morning in Pittsburg, not sure if you folks heard about that collapse.

 

[Demented]

No, its not difficult to remove a sidewalk from an adjacent structure.

The gravel strip/boardwalk was a straight forward exchange for the sidewalk/asphalt pavement that it replaced. The gravel free drains through the substrate and has no impact on the adjacent property which hugs the property line.

For skilled crews, it's easy. For the lowest bidder, not so easy. Pages 62 top 64 of the class action suite do appear to show damage caused by removal of that sidewalk. Water would definitely penetrate CTS from these points. This area of the building wasn't in good condition going back to the late 80's/early 90's, so definitely not the cause of the collapse, but without a doubt provided another hand in pushing the building past it's limits sooner.

https://ctsreceivership.com/wp-cont...ted-Second-Amended-Class-Action-Complaint.pdf

Potato images for those who don't want to look through the PDF.

 

[Sym P. le]

Thanks Demented, I've considered the damage shown by those images to be superficial. The construction detail as I understand it is that the sheet piles are driven, then the basement wall is poured to the inside of the sheets and capped by the slab. This concrete work is easy to finish and will be solid. The privacy wall then slightly overhangs the prior construction to create a finished line against the property and the lower overhanging portion is trimmed with block sections. This is not structural and can be (and was) refinished. When the slab fell away to the inside of the property, it broke away but left the privacy wall standing. Where the site was later stripped and the remaining portion of slab removed, the gravel sluffed in.

I have no reason to believe that the sidewalk removal might have damaged the slab or even remotely disturbed the sheet piles or foundation wall. Although Building Integrity made a pitch for slab tension compensating for failed column supports, and thus reason for perimeter damage to cause the collapse, I cannot agree with that extended reasoning.

A more damning image from the litigation is found on page 71:

Consider the following (green circle is 29/30):

Also, from page 60, if the east end of the property was settling, the vibration from 87 Park could be contributory.

EDIT X: Also, while I'm at it, all of the cracks that were readily apparent on the underside of the pool deck/parking slab would indicate significant topside cracks centered around each of the columns but hidden by the topping/tile work.

 

[MaudSTL]

Battle lines being drawn. From the Miami Herald, Feds try to block victims of Surfside condo collapse from accessing crucial evidence.

 

[Optical98]

Seems the Feds and the Miami Dade Police Dept suspect there's more to this event and they're wanting NIST to find that "needle" in the proverbial haystack.

 

[spsalso]

NIST has known since they were first given their task that people were going to want to examine the evidence. They have had months to work out a protocol, and one can only suppose they were successful in this endeavor, given the amount of time they had.

Therefore, they should be ready to provide that protocol to interested parties. And, in fact, to any US citizen who wishes to see it.

They very well may feel that they should restrict/control access to this evidence. They by now should be able to articulate the level of that control. And where their interests are not damaged, provide access.

If they can't/won't do this, it appears they are stonewalling. I think I would even remove the "appears".


spsalso

 

[Jeff Ostroff]

NIST could take the samples for everyone, why can't they do that? Then it's still under their control, while they satisfy the pleas of the plaintiffs and defendants.

 

[Optical98]

There's a few more details in this article -

Showdown in Surfside collapse saga, involving federal agency, could delay trial for years
Judge gave the parties 1 week to figure out evidence sharing

https://therealdeal.com/miami/2022/...g-federal-agency-could-delay-trial-for-years/

"NIST claimed exclusive control of the materials, citing a federal act, according to Goldberg, who also read the letter in court. But Goldberg countered that he “ripped through” the act and it does not give NIST exclusivity over evidence but mandates cooperation with others."

"Technically, the property belongs to the condo association, but the county’s police department has stored it, as it is doing its own investigation as well, Goldberg said."

"Miami-Dade argued in a court filing that if others are allowed to test the evidence, the county’s death investigation will be “compromised.” Hanzman denied the county’s pushback on the subpoena, mandating it to make all of the evidence accessible to the receiver and litigants."

 

[FJBnomics]

Looking at your failure mode overlay area showing construction joints, and the fact that rebar is missing in pictures of construction joint near pool, and BI’s jump rope theory;

it would seem jump ropes in failure mode area between building and south patio deck wall, may have be carrying much of the deck load.

The construction joints allow failure mode area to contract and expand east to west with less restraint than the North-South expansion and contraction of failure mode area, thus contributing to deck sag and allowing vibrations to create movement in deck.

Thus the Vibrations and thermal cycles would appear to stress the overstressed areas even more till rebar starts popping from sagging slabs and stress relief at tops of skinny columns.

I won’t waste any more time trying to explain why removal of slopped concrete pad allowed more water into garage, as that may have been very small contributing factor to collapse.

 

[Sym P. le]

Thanks thermopile, the explanation is elusive so once again I found myself thinking outloud. I find it peculiar that the only documented evidence of impending punch out was at the top of a column that didn't punch out. Moreover, although the approx. 30 foot span north to south may present an easy static calculation indicating weakness, the two way slab may have been facing its doom from forces playing the system at the east west margins.

 

[FJBnomics]

…..the explanation is elusive so once again I found myself thinking outloud.

Keep thinking out loud, as your logic is ‘Spot On’, especially in lite of the information black out to the public!

 

[Optical98]

Whoa just came across this lil gem -

Engineering Catastrophes: Miami Condo Calamity

Released January 26, 2022
Season 5 Episode 10

I just started watching it on Discovery+

Edit - 15 minute segment, nothing new... they only interviewed one former tenant from the West side of the building.

 

[MaudSTL]

I recently learned that Discovery Channel had an 84-minute special on Dec. 4, 2021 (prior to the Miami Herald infographic) called When Buildings Collapse: Disaster in Surfside. I just watched it, and found that it features new animations, including a new animation of Mike Bell’s lever theory (without attribution,) and images from other building failures that are used to illustrate theories about the CTS collapse. They don’t get the timeline right. But they do have new interviews with Gabe Nir of 111 and Ileana Monteagudo of 611, which unfortunately provide no new information, Fiorella Terenzi (who provided the garage video tour,) and a host of various types of engineers and TV presenters.