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
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[KingBobo]

The 2018 Morabito report describes "failure" of the waterproofing membrane that would have normally protected the structural slab of the pool deck. I don't recall if they mentioned it in their report, but one of the big contributors to that failure (aside from the general lack of maintenance) was a standing water situation caused by the defective design ("Gee -- looks like we forgot to include any drainage slope"). So I think there was a long-standing problem with moisture and chlorides attacking the slab reinforcing. Along the southern edge, that already bad situation could have been made even worse by the construction at 87 Park. At least that seems to be what the lawsuit is alleging.

 

[spsalso]

To be clear, isn't the waterproofing membrane for the pool deck laid out in a flat, horizontal manner, so as to keep water from penetrating downwards?

Here, we're discussing the water coming in from the edge, very likely below the level of that membrane.

spsalso

 

[SwinnyGG]

To be clear, isn't the waterproofing membrane for the pool deck laid out in a flat, horizontal manner, so as to keep water from penetrating downwards?

Yes, but no waterproofing membrane is waterproof indefinitely.

Waterproofing membranes all have some level of permeability; the membrane works because the permeability is low enough that water has time to drain away before penetrating the waterproofing system. If the system has ponding on top of it continuously, for an indefinite amount of time, eventually water is going to penetrate. Once that water has penetrated, it will take a similar long amount of time to disperse (because it's either absorbed into a substrate or it collects and must propagate back through the membrane in the other direction).

In other words, waterproofing a horizontal surface without providing any provision for drainage at the level of the membrane is a recipe for eventual failure if the local climate means standing water for long periods of time.

 

[spsalso]

So 87 Park would have had to do something to increase the leakage through the pool deck membrane, and that failure would have had to have been where the concrete span took off from the wall. Quite an accomplishment from an adjacent property.

The fail point under discussion is right under the inside of the above ground wall, right? What if water, perhaps pool water, leaked through right there?


spsalso

 

[Jeff Ostroff]

I see zero evidence that there was any vertical waterproofing on the southern wall like they do up north on foundation walls for the basement. At the southern edge of the pool wall that divides the Champlain Towers South from the 87 Park condo on the southern edge of it, photos from the lawsuit show actual open gaps from where the beach access sidewalk from 87 Park meets up against the wall for the pool. And you can see how easily water can get down there and so it doesn't take long to soak into the part of the wall that is underground where the rebar is which is probably maybe only inches down from that ground level. Although a caveat is that the water has to soak through concrete blocks also. I would love to see some recent photos from inside the garage on the southern end right up against that wall there to see if any water had leaked down into the garage. Also 87 Park builders should have waterproofed that whole area, and I would love to see what their drainage plan is for this development along that beach access sidewalk.

AusTony2046 to answer your question on how that minuscule movement could have brought down the building. Once the pool deck detaches from that south wall if that is indeed how it started, the pool deck propagated north towards the building where it hits the planters over Column M 11.1. Once you hit that point and column 11.1 falls, now added loads are on the remaining spindly/damages/waterlogged columns in the area. When the rest of the planters in the pool deck fall, everything else in that area has already been weakened including the area where the fitness center is as indicated by the Miami Herald article. As the pool deck starts to collapse down there's that beam that runs the whole length of the southern end of the building that begins to rotate and as it rotates it tears away from the other three or four columns along the southern edge of the building so they will begin to collapse.

 

[spsalso]

So there was likely no waterproofing to obstruct horizontal travel of water from the adjacent property. Was this a common practice at the time? Is it still? If it is/was not, it implies it was an accepted practice.

Of course, if the water that caused the damage came from the other property, it arrived at the southernmost part of the rebar first, and the bend in the rebar would likely be the most corroded, being more impacted by the encroaching water.

In his video from August 13 of last year, Josh Porter noted that the concrete deck was heavily overloaded in the area where some beams were removed during a redesign. This would be where the surface level parking met the pool deck. With that, I believe he thought it likely that the failure started there.

If it did, the fail would have had to proceed eastward, towards the pool. The weight of the falling slab would have hit the rebar connecting the south underground wall with the pool deck unevenly, in that the greatest load on all the rebar would have been on the first one to the east. If the weight was enough, it perhaps could have sheared. Then the next rebar would be heavily loaded, and it would shear. And the next, in a zipper fashion, all the way to the expansion joint.

So perhaps the rebar wasn't particularly weakened by water in this area; perhaps it was overloaded in shear.


spsalso

 

[Keith_1]

The "Building Integrity" guy is a complete idiot! The slab is irrelevant, the load rests on columns and the beams that distribute that load. I have never really cared what happens to subgrade walls or slabs once a building is constructed in this region simply because after dewatering and construction the weight of the building results in a hydrostatic environment that prevents water intrusion at subgrade.

The membrane is extremely important to protect the beams and from being weekend, in this case the beams failed, which resulted in very large loads being transferred to single points that were so overloaded that the building failed.

I stated a few posts back that the sheet piles were nothing more than a means to an end, which was to excavate, dewater and pour non-load bearing walls, and trust me that zero load is exactly what the perimeter wall carries.

The "Membrane" is simply to protect the beams and columns, the slab is merely there to provide a nice flat surface to walk or drive upon.

What will really screw with you is in post-tension construction, it is 100% forbidden to have any load transfer on a wall.

 

[Nukeman948]

Well, I have to admit, I had never considered "a hydrostatic environment" preventing water intrusion to be a factor in this building. Learn something new every day.

Enjoy your weekend.

​

 

[spsalso]

I would think the slab falling down would be relevant. If nothing else, it squashed a lot of cars.

According to the complete idiot, the beams you refer to as distributing the load were removed from the plans without doing structural correction for the removal.

If the perimeter wall carries zero load, why even connect to it? If it carries zero load, you could stop the slab an inch short. And save a couple of bucks.


spsalso

 

[Optical98]

The southern perimeter wall where the upper parking was, that would have needed to bear some weight I would think.
The columns were larger there, but some weight would have needed to be distributed along the wall as well...and that did collapse.

Those beams that were in the plans but left out along that area, that was a huge mistake with both the weight of the vehicles and the planters there.

 

[spsalso]

My thought, which I may have not expressed well, is that the points of failure of the rebars between the south wall and the slab might have been caused by the vehicle/planter slab falling, and unzipping/shearing those pieces of rebar as it took down the adjacent pool deck slab.


spsalso

 

[Keith_1]

The "south" wall or any other similar subgrade wall has no direct compressive load from the building, nor is there anything that transfers that compressive load to said members, therefore it is irrelevant.

 

[Keith_1]

In terms of hydrostatic pressure, yes it can be a concern because sometimes buildings can sctually float until such time there is enough weight to surpass equilibrium, and the soil becomes dense and compacted enough that it becomes impermeable

 

[Sym P. le]

Keith, the discussion of the video was regarding the deck slab failure, which ties into the south perimeter wall.

 

[IEGeezer]

With my bad hearing this is the best I could do for the spanish audio tracks on the Dec 30 Miami Herald article (

https://www.miamiherald.com/news/special-reports/surfside-investigation/article256633336.html):

Vázquez story:

Entonces en el auto, como siempre en la cochera, ya escuchamos un ruido muy, muy ... muy fuerte. Pero no seamos(?) a ... a entender que pasaba.
Y en diferencia de seis, de segundos, de segundos, el ascensor ... se movió el ascensor, parando en el lobby como siempre
Y umm arrancó una ... una polvareda muy fuerte, un estruendo muy fuerte como si fuera ... no sabía - no entendía que pasaba.

Then (we were) in the car, as usual in the parking garage, we heard a noise, very, very ... very loud. But we didn't get(?) to ... to understand what was happening.
And after six, after seconds, after seconds, the elevator ... the elevator moved, stopping at the lobby, as usual. And ummm a ... a very strong cloud of dust started, a very loud noise started as it it were ... I don't know - I didn't understand what was happening.

Sarmiento's story:

Cuando salímos (???) como a las una y cuarto de la mañana a la piscina, eh yo siento, como es un campo abierto, la zona de la piscina, yo siento un ... un colapso. Boom. eh Sale aire y un viento después de que colapsa el techo del estacionamiento. Sale un viento por el garage y empiezan a sonar las alarmas de los carros. Empieza a sonar los chorros de agua y de (???) a mirar para todo lado a mirar de donde salió ese sonido porque era algo extraño. Sabía que algo estaba pasando. Cuando yo veo el techo del estacionamiento prácticamente todo ese pedazo en el piso y los tubos rotos botando agua, yo le digo a la gente que está ahí que es mi esposo y (???) le digo: Eso se va a caer.

When we were going (???) about 1:15 AM to the pool, uh I felt, since it is open, around the pool, I felt a ... a collapse. Boom. uh Air comes out and a wind after the collapse of the roof of the parking garage. A wind comes out of the garage and the car alarms start going off. You can start hearing the water coming out and (???) I start to look everywhere to see where that noise came from because it was somewhat odd. I knew that something was happening. When I saw the ceiling of the parking garage practically all that piece on the floor and the broken pipes with water pouring out, I said to those around me that was my husband and (???) I say: That is going to fall.

Monteagudo's story:

Yo siento dos crujidos eh seguro muy fuerte. Cuando miré a mi costado derecho, ví que estaba bajando una una raja... una grieta del techo hacia el suelo por la pared y esa grieta, a medida que avanzaba, separaba a la pared en dos.

Eso se fue un decimiento(?) que empezó a hablar y a decirme: tiene que irse de aquí porque eso se va a ... a caer.

I heard two cracking sounds uh for sure very loud. When I looked to my right side, I saw coming down the wall a a crack.. a large crack from the ceiling to the floor along the wall and that large crack, as it grew, cleaved the wall in two.

It was something(?) talking to me and saying to me: You have to leave because this is going to ... to fall down.

 

[IEGeezer]

I think I may have solved the mystery of the crack in 611 (Monteagudo). The Miami Herald article shows the crack on the east wall of 611, which would be along the Row M of columns. Based on another look at her testimony, it would appear that the crack is on the opposite wall. The Miami Herald shows the following illustration:

Based on a study of the transcript (corrected) of her testimony, which is referenced in the Timeline, she was apparently facing her balcony door, which wouldn't close, when the crack appeared to her right. Accordingly, the crack would be on the wall between the living room and the bedroom as shown as follows:

As you can see, this is much closer to Row L. Thus the crack would be consistent with the theory by Mike Bell, which theorizes that the building collapse begun with columns K9.1, L9.1 and M9.1 and not near the weight room. It would appear from the transcript that Mrs. Monteagudo woke up when the pool desk collapsed and barely made it to the western staircase before the building collapsed, which took about 7 minutes. The collapse sequence then may have been as follows:

A. Pool Deck collapses. I still favor the collapse at the edge of the parking deck due to fatigue failure and not at the southern wall.
B. The pool deck collapse damages columns K9.1, L9.1 and M9.1, so that they are no longer able to support the facade. A small displacement would suffice. The building immediately begins to find new load paths. Unfortunately, the step beam along Row 9.1 was apparently NOT anchored to the shear wall at the elevators. I have not been able to find a structural detail for how the step beam was supposed to be anchored to the shear wall. Unfortunately, I have not been able to find any pictures which show that detail. However, it appears that the entire building was not anchored to the shear wall very well if at all.

Here is an animation of Mike Bell's theory:

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1642399134/tips/Mike_Bell_animation_8AXsK1D_p1ffhn.webp[/url]
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1642399167/tips/Mike_Bell_animation_qsfZCKn_mxs50h.webp[/url]

The English translation of Mrs. Monteagudo's testimony from the above referenced you tube clip is as follows:

I was sleeping and a higher power woke me up that there was an unusual atmosphere in the apartment and I heard some strange sounds. I thought that I had left the balcony door open and when I went to the living room, indeed the door was open from the living room to the ocean, to the water, to the balcony. I tried to close it and I couldn't. It seemed as if the door track was no longer level. And then I heard another crack (at about 00:45 she turns to her right) and when I heard this crack I look at the wall and I see a large crack going down from the ceiling that was two fingers wide. Something told me: this is going to fall. I ran to the bedroom. I took off my bed clothes. I put on a dress, some flip-flops or whatever you call them and I got to the dining room. I took my purse that had my ID and my credit cards, a pill box, the key and these things that I had taken off that I still had I put them in. I put out the candle to the virgin Mary and just in case I closed the door. I didn't know where the exit stairs were. I went to the elevator that was much further away. I did not know that I had two exit stairs next to my apartment. If I had know that there were two exit doors next to my apartment, I would have thought to take the quickest one. And I wouldn't have gone to the one further away. Anyway when I was in the furthest staircase, when I got to about the fourth (sixth - fourth) floor, I heard an infernal noise, but an infernal noise that I knew that part of the building had fallen down. I saw the security very thin like a little boy that said there had been an earthquake that there had been an earthquake and I said it wasn't an earthquake. This had fallen: the building - this one and suddenly the legs failed me, I don't know, but I got the top that I needed to get to. Then there was an enormous space that I had to jump - another obstacle to reach the street but I couldn't. Then God found me a piece of rubble that served as a step. I put my foot on the step - the right foot - the left foot that was enough so that I could get to solid ground.

The corrected and punctuated Spanish transcription is as follows (I have only transcribed Mrs. Monteagudo's testimony):

Yo estaba dormida y una fuerza superior me despertó que había un ambiente enrarecido en el apartamento y yo sentí unos ruidos extraños. Yo pensé que había dejado la puerta del balcón abierta y cuando voy a la sala, efectivamente estaba abierta la puerta de la sala al mar, al agua, al balcón. Traté de cerrarla y no pude. Parece que se había desnivelado ya el riel de la puerta. Y siento otro crack y cuando siento este crack que miro la pared veo que viene bajando una grieta del techo para abajo de dos dedos de ancho. Algo me dijo: esto se va a caer. Salí corriendo al cuarto. Me quité la ropa de dormir. Me puse un vestido, unas chancleticas de meter el dedo y cómo se llama y llegué al comedor. Agarré una cartera que tenía con mi ID y mis tarjetas de crédito, un pastillero la llave y estas cosas que me las había quitado las tenía encima las metí. Apagué la vela de la virgen y por si las moscas cerré la puerta. Yo no sabía donde estaban la escaleras de escape. Me fuí al ascensor que me quedaba mucho más lejos. Yo que yo no sabía que yo tenía dos escaleras de escape al lado de mi apartamento. Si yo sé que hay dos puertas de escape al lado de mi apartamento, me hubiera ido pensando que la rapidez. Y no me voy a la lejos. Bueno pues en la lejos cuando llegó por el piso 4 y 6-4 yo siento un ruido infernal, pero un estruendo infernal que yo sabía que se había caído parte del edificio. Ví al security flaquito asi (como) un niño que decía tuvo un terremoto tuvo un terremoto y yo dije no es un terremoto. Esto que se derrumbó: el edificio - este y de repente las piernas (me fallaron) que se yo pero llegué al tope que tenía que llegar. Después estaba un espacio enorme que tenía que saltar otro obstáculo más para llegar a la calle pero no podía. Pero Diós me puso un escombro que me sirvió de escalón. Puse el pié en ese escalón en la pierna izquierda la pierna derecha me dió para llegar a tierra firme.

The corrected Spanish transcription retaining the you tube timing is as follows:

00:21 ...... (START) yo estaba dormida y una
00:24 fuerza superior me despertó que había un
00:27 ambiente enrarecido en el apartamento y
00:29 yo sentí unos ruidos extraños yo pensé
00:31 que había dejado la puerta del balcón
00:32 abierta y cuando voy a la sala
00:35 efectivamente estaba abierta la puerta
00:36 de la sala al mar al agua al balcón
00:39 traté de cerrarla y no pude parece que
00:41 se había de nivelado ya al riel de la
00:43 puerta
00:44 y siento otro crack y cuando siento
00:47 este crack que miro la pared veo que
00:49 viene bajando una grieta del techo para
00:51 abajo de dos dedos de anchos algo me
00:54 dijo esto se va a caer
00:56 salí corriendo al cuarto me quité la
00:58 ropa de dormir me puse un vestido unas
01:00 chancleticas de meter el dedo
01:03 y cómo se llama y llegué al comedor agarré
01:07 una cartera que tenía con mi ID y
01:10 mis tarjetas de crédito un pastillero
01:12 la llave y estas cosas que me las había
01:15 quitado las tenía encima las metí apague
01:18 la vela de la virgen y por si las moscas
01:20 cerré la puerta yo no sabía donde estaban
01:22 la escaleras de escape me fui al ascensor
01:25 que me quedaba mucho más lejos yo que yo
01:27 no sabía que yo tenía dos escaleras de
01:28 escape al lado de mi apartamento si yo
01:31 sé que hay dos puertas de escape al lado de
01:33 mi apartamento me hubiera ido pensando
01:35 que la rapidez y no me voy a la lejos
01:38 bueno pues en la lejos cuando llegó por
01:41 el piso 4 y 6-4
01:44 yo siento un ruido infernal pero un
01:46 estruendo infernal que yo sabía que se
01:50 había caído parte del edificio ví al
01:52 security flaquito asi un niño que decía tuvo un terremoto
01:56 tuvo y yo dije no es un terremoto esto que se
01:58 derrumbó el edificio este y de repente las
02:01 piernas que se yo pero llegué al tope
02:03 que tenía que llegar después estaba
02:05 y un espacio enorme que tenían saltar
02:08 otro obstáculo más para llegar a la calle pero no podía
02:12 pero Diós me puso un escombro que me sirvió de escalón puse el pié en ese escalón en
02:18 la pierna izquierda la pierna derecha me
02:20 dio para llegar a tierra firme (STOP) ...

 

[IEGeezer]

Hat tip to clouditguy:

Matterport (3D walkthrough) supposedly of 611:

https://my.matterport.com/show/?m=4USu8mRgGim&mls=1

 

[MaudSTL]

Great work, IEGeezer. I have always theorized, based on the interview you translated, that it was the west wall that cracked. After I saw the latest infographic showing the crack in the east wall, I searched for new interviews with Ms. Monteagudo that might support the infographic and found nothing. If it is correct, the 3D rendering showing her furnishings makes it clear that the most unobscured living room wall was on the west.

 

[Keith_1]

Ok, ENG 101

This is a pile foundation which means that all compressive loads (weight of the building) are transferred directly into the ground. The Beams in the garage simply distribute the load from the top floor down to the piles. The video clearly shows that there was no tie in to the deck at the perimeter wall.

If there was a structural load bearing /transferring connection between the perimeter wall and deck, it would be tied into the piles, and there would be a transfer beam. This makes no sense, because you would be taking a tension load and trying to put it in tension. This is just stupid.

I don't care about Ms. X experience, the beams failed due to failure to protect the membrane and the compressive loads were no longer transferred, that is it.

Decks are just to stand on, and yes there is a limit on the static and live load of the deck in terms of span length, but unless you are going to put up some serious analysis regarding the capacity of the span in this instance, you look like idiots.

 

[SFCharlie]

If there was a structural load bearing /transferring connection between the perimeter wall and deck, it would be tied into the piles, and there would be a transfer beam. This makes no sense, because you would be taking a tension load and trying to put it in tension. This is just stupid.

I don't care about Ms. X experience, the beams failed due to failure to protect the membrane and the compressive loads were no longer transferred, that is it.

Decks are just to stand on, and yes there is a limit on the static and live load of the deck in terms of span length, but unless you are going to put up some serious analysis regarding the capacity of the span in this instance, you look like idiots.

Dear Keith,
I just looked at the plans.
There are NO columns at the south side of the VALET parking slab.
What holds up the cars and planters?
If you don't care about the occupants of the building, I would hate to be in one of your buildings!
Maybe it was someone like you that designed this just stupid building.

(OK OK, I'll climb back in my teapot now...)