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Hard Rock Hotel under construction in New Orleans collapses... 119
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NOLAscience
Structural
retired13 said:
Exactly.
There are two swimming pools in the design: one had been lifted into place a day or so before the collapse and the other one (roof pool) was not on site yet.
There was no water in the pool which was in place on about the 14th floor. It is still in place, intact, with a hole drilled into the bottom after the collapse to prevent water accumulation.
NOLAscience
Structural
At least the media has finally been made aware of the problems with the transfer framing at the 14th and 16th Floors -- AND the lack of current drawings on the city's permitting website.
<< The plan also called for the placement of columns to change at the 14th floor, and again at the 16th. Those “transfer floors” also brought different layouts for the metal decking.
But those details also remain out of the public eye, making any firm conclusions about the cause of the collapse elusive.
“We still don’t know really what they were building,” Lenkin said regarding the hotel’s upper floors. “We know they were building a hotel. We don’t know what the structure was.” >>
Boris_Kuznetsov
Structural
After the heavy swimming pool was installed on 9th floor of Hard Rock hotel, the concrete deck supporting the pool sagged. It leads to significant drop in the floor rigidity. Sagging floor can not be qualified as rigid support for column stability, only as elastic support. The standard method of column design becomes not applicable. The Designer could use different methods including one described in work of American engineer and scientist S.P. Timoshenko: "Stability of columns on elastic supports". This may lead to:
1) The change of the buckling mode from columns buckled in its middle to columns inclined toward of the sagging floor.
2) Significant decrease of the buckling loads, possibly below the applied loads.
As a result, these columns could buckle and the building could collapse.
The picture of the building after the collapse shows that all columns above 7th floor were inclined into direction of the swimming pool and the floors were sagged. This picture definitely confirmed that the possibility of the collapse was realized in accordance with the theory.
1) The change of the buckling mode from columns buckled in its middle to columns inclined toward of the sagging floor.
2) Significant decrease of the buckling loads, possibly below the applied loads.
As a result, these columns could buckle and the building could collapse.
The picture of the building after the collapse shows that all columns above 7th floor were inclined into direction of the swimming pool and the floors were sagged. This picture definitely confirmed that the possibility of the collapse was realized in accordance with the theory.
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- #325
Boris, just stop. Your ranting about a "heavy swimming pool" doesn't help. For one thing, this was a prefabricated pool, lifted into place by crane, so it was not heavy, and not filled with water. None of us has sufficient knowledge of the structure to identify exactly why it failed, but that is not important. It failed because the steel structure of at least some of the upper levels was not strong enough.
MacGyverS2000
Electrical
Boris, are you even bothering to read the articles posted or what others have posted to date?
Dan - Owner
Dan - Owner
Boris_Kuznetsov
Structural
How much are steel beams deflected before the building collapsed?
Any updates on this building? A few questions:
1. Who is actually investigating this project? Any idea on the consultants or agencies involved?
2. What is the demo plan? When?
3. Does any one have a similar sized project going on in their backyard that feels similar? Meaning, the rumor mill is churning that there are issues but the project sleepwalks forward?
"We shape our buildings, thereafter they shape us." -WSC
1. Who is actually investigating this project? Any idea on the consultants or agencies involved?
2. What is the demo plan? When?
3. Does any one have a similar sized project going on in their backyard that feels similar? Meaning, the rumor mill is churning that there are issues but the project sleepwalks forward?
"We shape our buildings, thereafter they shape us." -WSC
Boris_Kuznetsov
Structural
Boris Kuznetsov (structural)
Post tension constructions in general and Hard Rock hotel in particular have concrete slabs with long spans and thin thicknesses. It may change buckling mode and critical load of building. Therefore, additional column stability check, not included in standard column design, is needed:
P < E c x bc x h x H / L (1)
where:
P - load on column,
E c - modulus of elasticity of concrete,
bc - tributary to the column strip of concrete slab,
h - thickness of concrete slab,
H - floor height,
L - span of concrete slab.
Formula (1) was derived in assumption that stesses in concrete are in elastic limits. If some plasticity is allowed in concrete slab, formula (1) should be adjusted accordingly. If formula (1) is not met, Hard Rock hotel collapsed because of insufficient rigidity of concrete slab and its span was too long or its thickness was too thin.
Post tension constructions in general and Hard Rock hotel in particular have concrete slabs with long spans and thin thicknesses. It may change buckling mode and critical load of building. Therefore, additional column stability check, not included in standard column design, is needed:
P < E c x bc x h x H / L (1)
where:
P - load on column,
E c - modulus of elasticity of concrete,
bc - tributary to the column strip of concrete slab,
h - thickness of concrete slab,
H - floor height,
L - span of concrete slab.
Formula (1) was derived in assumption that stesses in concrete are in elastic limits. If some plasticity is allowed in concrete slab, formula (1) should be adjusted accordingly. If formula (1) is not met, Hard Rock hotel collapsed because of insufficient rigidity of concrete slab and its span was too long or its thickness was too thin.
![[bigsmile]](/data/assets/smilies/bigsmile.gif "[bigsmile] [bigsmile]")
NOLAscience
Structural
1. I've been trying to find this information since about Nov. 1st. No idea.
2. The demolition plan now includes demolition of 3 nearby (historic) buildings:
Two of the three buildings "belong to companies owned by developer Mohan Kailas, whose firm is the majority stakeholder in the Hard Rock project".
"City officials had initially hoped to bring down the rest of the building through controlled demolitions. But those plans were changed to a much lengthier process of first shoring up the building before taking it apart piece-by-piece, in large part because of fear of the damage an implosion might cause to nearby buildings and infrastructure."
The developer may be exaggerating the need for the demo of the three buildings -- to clear the way for some other use to recoup cost of this disaster.
3. I'd like to know this, too.
It certainly appears as if the demo of this will get drawn into a lengthy court battle now. Already talk of hiring competing experts.
It may be time for the city to take control and remove the developer / GC from this process. This would expose them to some financial risk, which leads to questions that I have had for some time now. Questions, that I doubt anyone really has the answers to right now.
1. What would the AOR and EOR be required to have in terms of liability insurance on a project of this scale? There is no way that it is enough to cover the damages. This will almost certainly lead to bankruptcy of those companies. The litigation costs alone would do that.
2. These projects are typically done as LLC’s and set up as there own entity. The developer would not have funded the LLC with enough capital to cover the costs of the demo, compensation to families and injured workers. What is stoping them from declaring the LLC bankrupt and walking away?
3. Of both of the above happen, who is left to clean up the mess? The only real option would be the city, but that would take a prolonged legal process.
4. What are the odds of this thing being Cleaned up in 2020? At best, I say 50/50.
The outfall from this has the potential of changing a lot of aspects of our industry
It may be time for the city to take control and remove the developer / GC from this process. This would expose them to some financial risk, which leads to questions that I have had for some time now. Questions, that I doubt anyone really has the answers to right now.
1. What would the AOR and EOR be required to have in terms of liability insurance on a project of this scale? There is no way that it is enough to cover the damages. This will almost certainly lead to bankruptcy of those companies. The litigation costs alone would do that.
2. These projects are typically done as LLC’s and set up as there own entity. The developer would not have funded the LLC with enough capital to cover the costs of the demo, compensation to families and injured workers. What is stoping them from declaring the LLC bankrupt and walking away?
3. Of both of the above happen, who is left to clean up the mess? The only real option would be the city, but that would take a prolonged legal process.
4. What are the odds of this thing being Cleaned up in 2020? At best, I say 50/50.
The outfall from this has the potential of changing a lot of aspects of our industry
NOLAscience
Structural
Demolition plan extended to December 2020:
Stabilization work extended to May 7th.
Stabilization work extended to May 7th.
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- #338
So, unskilled labor will risk their lives for a few dollars an hour to shore the unsafe structure up?
Maybe bring back the deportee to help?
We had a similar situation here on one of my buildings after a fire during construction, a 20 or so story post tensioned building, still just a frame. Tendons were almost completely destroyed in the band lines a few stories up.
The lawyers for the insurance company wanted to shore it up and continue to study. I said ok, but use smart lawyers to do the work, not poorly paid construction workers.
The city backed down and would do nothing.
We went to the board of rules and appeals of the county for a demo permit on an unsafe structure and got it.
We imploded the building while the lawyers were still objecting.
No one was hurt.
Maybe bring back the deportee to help?
We had a similar situation here on one of my buildings after a fire during construction, a 20 or so story post tensioned building, still just a frame. Tendons were almost completely destroyed in the band lines a few stories up.
The lawyers for the insurance company wanted to shore it up and continue to study. I said ok, but use smart lawyers to do the work, not poorly paid construction workers.
The city backed down and would do nothing.
We went to the board of rules and appeals of the county for a demo permit on an unsafe structure and got it.
We imploded the building while the lawyers were still objecting.
No one was hurt.
MOJOJOHN said:
Unsafe damaged buildings require shoring all the time. What is the alternative? To implode a building, don't workers have to enter the building to set charges and the like (I know nothing about imploding buildings)? It is risky business either way I guess. Perhaps the workers (and engineers entering the buildings also) should be compensated handsomely for working in the dangerous buildings, but what else can be done? Call in an air strike maybe?
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