Miami Beach, Champlain Towers South apartment building collapse, Part 03 148

[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

Thank you

SF Charlie
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[SFCharlie]

by itself? or did it need help?

It got excellent help.
WATCH LIVE: Surfside tower demolition

SF Charlie
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[Js5180]

Notice in the demolition video, looking south - the parapet over the x04 living room came free completely and yet remained intact. As if it wasn’t attached at all.

 

[davefitz]

Reviewed a little history of the use of modern admixtures in concrete to reduce its permeability to chloride ions, and it seems that the modern use of super plasticizer was not common in the USA circa 1980 when this condo was built. Reducing the water/cement ratio to below 0.4 and adding fine pozzalans is used today to reduce the diffusion rate of chloride ions to the rebar, and the plasticizer aids in reducing the water to cement ratio. If the workability was not enhanced by using plasticizer, is it possible they added calcium chloride to improve workability but compromised rebar life?

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[dik]

I figured the w/c would be between 0.4 and 0.45. With RJC and the parking garage experience they had, we were typically using 4.5 to 5.0 ksi stuff back then for parkade slabs and 1-1/2" min cover for slabs and 2-1/2" for columns as well as 4" slump was common... substantially higher than most consultants at the time. This was not for a marine salt environment... put typical de-icer salts.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

More news... looks like the condminium corp was more interested in putting 'lipstick of the pig' than fixing real problems...

"Following a Miami Herald report that it took more than a month for the town to respond to plans submitted by the building's board in May, town manager Andrew Hyatt released a statement saying the issues under discussion were preliminary plans unrelated to structural work and not permits to begin repairs the building needed to pass a 40-year recertification.

“It would appear that the Champlain Towers South Condominium Association sought to address a number of issues outside the scope of any proposed 40-year re-certification work,” such as new natural gas lines and added parking, Hyatt's statement said. “There was no indication during any communications between the Town and the association by telephone or electronic mail that this submission required emergency action by the Town of Surfside.”

Emails first obtained by the Herald show the condo building manager growing impatient at the lack of response from the town to plans for a temporary parking plan needed to move forward on repair of a concrete slab under building's pool and on damaged columns in its garage."

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Lukeuk99]

Just some Links showing the remaining structure coming down ... differing angles.

https://www.nbcmiami.com/news/local...emainder-of-collapsed-surfside-condo/2487680/

https://wsvn.com

https://www.local10.com/news/local/...scue-operation-at-surfside-building-collapse/

 

[dik]

The initial collapse was far more elegant...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[warrenslo]

"Following a Miami Herald report that it took more than a month for the town to respond to plans submitted by the building's board in May, town manager Andrew Hyatt released a statement saying the issues under discussion were preliminary plans unrelated to structural work and not permits to begin repairs the building needed to pass a 40-year recertification.

This is not true, based on the emails, 87 Park (to the south) removed 22 on-street parking spaces, the building wanted to add temporary parking spaces along 88th and additional spaces on the oceanside to allow for structural work in the garage. The emails about this are in the link sent earlier today, and discussions were ongoing up to days of the collapse. The town is seriously trying to cover this up.

 

[warrenslo]

Notice in the demolition video, looking south - the parapet over the x04 living room came free completely and yet remained intact. As if it wasn’t attached at all.

Definitely an interesting development...

 

[Murph 9000]

WOW, to do that in 24hrs, without any prep, I'am simply speechless. I didn't think that they were only doing were doing any placement of charges above the 1st elevated floor, but I was clearly wrong. I have no Idea how this was mobilized, or performed in such a quick manner, but WOW.

That's the Loizeaux family for you. From what I read, it was basically small sequenced charges in the columns at basement and ground level, nothing in the tower. Gravity and relatively weak slab-column connections did the rest.

 

[warrenslo]

Warrenslo,

What is the ENR report? Can you (re)post a link please?

Also, isn’t that triangular hole in a CMU wall? It looks to me like the slab along that whole area has been pulled out, leaving a horizontal hole and taking a chunk of CMU wall with it over the staircase. Or is that your point? The slab was pulled out, rather than snapped like the rest of them?

ENR article (paywall but there's a few free articles prior to required payment):

Surface Parking Zone of Interest
An area of interest is the surface parking zone near the lobby entry drive that goes partly under the remaining wing. That slab for the parking, which is next to the grade-level pool deck, is the roof of a one-level basement garage that fills the site's entire footprint.

According to Kilsheimer, it appears, from the position of the cars that dropped a level—one car’s nose ended up pointing to the pool area—that the lobby slab columns moved sideways toward the pool deck, causing the pool deck to drop, which then pulled on the tower columns, causing them to fail. “This will not prove where it started,” he says. "That is not something we can determine in a hurry."

However, Kilsheimer has all but ruled out an overload from the parked cars as the trigger. “It could be that a drunk driver hit a column,” he says. “We don’t know yet.”

KCE and Mueser Rutledge will soon be joined at the site by another investigating team. Also at the press conference, the National Institute of Standards and Technology of the U.S. Dept. of Commerce announced it will soon be launching a technical investigation into the causes of the failure under the authority it was given by the 2002 National Construction Safety Team Act.

Yes, that is my point, the upper parapet over x10 seems to have fallen in a different direction and more slowly than the rest of the building.

 

[warrenslo]

I just want to comment regarding inspections. The only way to attempt to avoid massive corruption is to have the insurance companies do the inspections since they have the liability.

Agreed, there are many development companies, including my own, who partner with insurance companies who require third-party review. With that said the Harmon Hotel in Las Vegas' third party inspector missed the shear wall error requiring the building's demo.

 

[Vance Wiley]

The part about repairs to slabs and columns in the pool area sounds quite important to me, particularly when viewed from the events of the last 10 days or so, and should have deserved serious attention by the "town" in my opinion.
As stated, it appears the focus was on temporary parking when it should have been on structural repairs.
Even that may have been only "lipstick" for the pig.
I imagine next time the manager will not wait for approvals.

 

[warrenslo]

Like I have said we are a self-regulating industry, we write the codes, I think there is a need for us to do so.

Annual or bi-annual Type A inspection (fire, electrical, easy to spot things) and 10-year Type B inspection (structural, more detailed etc.) I think is the solution. With that said, if OSHA roof anchor testing caused this, then that needs to be addressed - now. If these old buildings weren't designed for anchors, and they clearly could be accessed from a cherry picker, why are they being pushed by a structural engineer before structurally repairing/shoring up the building?

The roof anchors are a grey area as the IBC doesn't address them and the roof anchor contractors are my second least trusted sub after the window guy (why can't they ever get the right window in the right spot.)

 

[Vance Wiley]

VERY good points - more attention to protecting the reinforcing. I was thinking about the difference in bridges and overpasses in the Miami environment - more concrete cover, more dense concrete - and much longer life expectancy. The Construction details of this building appear to be those of a building with complete protection from the environment.
I am curious - how far from the coastline do the salt conditions extend? At what point can they be dismissed? The slab over the parking near the pool certainly looks like a concern in this regard.

 

[JAKLED]

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1625470464/tips/penthouse_24_ROOF_ppcrfe.pdf[/url]

I have circled what appears to be roof anchors that may have been the initiating "boom" that caused the sequence of events.

The picture was taken from a prior thread focusing on the pool deck but looking at it now seems to give more details.

 

[GeorgeTheCivilEngineer]

I'm behind the conversation by a few days, but when discussing the role of 'state wide agencies' in mandating building safety, there are some parallels with the Grenfell tower fire disaster in the UK.

Although the inquiry is still ongoing, a few years after a renovation (including external insulation/cladding) a huge fire engulfed the building due to inappropriate cladding systems being used, killing 72 people.

The long term solution to prevent this from happening is to introduce the 'Building Safety Regulator' who will specifically be responsible for the safety of construction of high rise (18m+) buildings.

The legislation has just been presented to Parliament so a lot of details are yet to be determined, but it will be interesting to see whether they begin a routine inspection of existing building, as has been suggested earlier in these thread(s) (many other tall buildings have found inadequate fire protection measures, fire doors + fire stops etc in the post-Grenfell inspections).

 

[Lukeuk99]

GeorgeTheCivilEngineer - "there are some parallels with the Grenfell tower fire disaster in the UK"

Sadly the loss of life at both Grenfell Tower in the UK, and at Champlain Towers is similar / has parallels - the (apparent causes) differ.

At Grenfell, the cause was flammable cladding, that was ironically approved by UK building regulations for use. It turns out it's the regulation related to it's method of install was at fault at Grenfell, but it was legally installed and a permitted method of installation at the time. The foam/polyurethane sandwiched in foil panels, and used for insulation, were installed with no protection of the edges, up the side of the building, on a metal framework, so hence when the fire heated up the first panels on the 4th floor, it melted/set fire to the first, the fire just continued, jumping from panel to panel, with the metal frame creating an unfortunate breathing gap for the fire, with no barrier or protection to stop it moving to the next !

In the UK, the Grenfell structure remains standing in West London (I get to drive past it occasionally), it's shrouded in scaffolding and plastic sheeting. I'm not sure what the longer term plans are !

The common issues from both Grenfell and Champlain that need to be addressed are numerous eg. "better/stronger regulation regarding checks and ensuring current/known building issues are either adhered to, or corrected (where possible)". Also both buildings appear to have had problems with their respective management/resident companies, who either had a lax approach to building issues, or just delayed/bickered/ignored - causing delay and on occasion compounding issues.

 

[alr1970]

In the UK, the Grenfell structure remains standing in West London (I get to drive past it occasionally), it's shrouded in scaffolding and plastic sheeting. I'm not sure what the longer term plans are !

It has been propped up but will have to be demolished soon.
"Engineers are warning that the Grenfell Tower must be carefully dismantled before May 2022 because of continued deterioration of exposed concrete structures."
There are some locals and survivors who wan the structure restored and planted as a vertical garden memorial.

 

[Lukeuk99]

It has been propped up but will have to be demolished soon.
"Engineers are warning that the Grenfell Tower must be carefully dismantled before May 2022 because of continued deterioration of exposed concrete structures."
There are some locals and survivors who wan the structure restored and planted as a vertical garden memorial.[\quote]

Good to know something is being done. The heat alone from the fire - must have seriously degraded the structure (as suggested in the articles). It stood for months like a huge black burnt-out tomb stone to those who lost their lives - before the plastic sheeting went up.