New Jersey Collapse 1

[dik]

From the Chicago Tribune:

ATLANTIC CITY, N.J. -- A five-story section of a parking garage under construction collapsed Thursday, injuring at least two people, officials said. At least two others were missing.

Robert Levy, director of emergency management for the city, said officials were sending search cameras to look through the rubble for any dead or injured workers. The garage is being built at the Tropicana Casino and Resort.


"We are planning for the worst. It's one of the worst collapses Atlantic City has ever seen," Levy said.

One end of the building collapsed, leaving five layers of concrete and steel sloping downward at a steep angle.

 

[unclesyd]

Someone gambled and other people lost.
It's a damn shame that the the people responsible don't have their offices on the first floor until a building is completed.

 

[ishvaaag]

It also reminders many of why they are not fond of prestressed structures (of course, inference). And as well of too small seat supports. Have not the engineers played with wood pieces when children? Then everyone knows that what are mostly simply supported structures better be well seated if there is something able to mess with support itself. The supports used in most of the precast simply supported beams are akin in extent to putting the wood pieces just barely in the seats. Building with precast part may be children's play, but even children seem to have better knowledge on how things are soundly built.

 

[structuresguy]

Very true ishvaaag. I personally like precast structures, but they really are like a "house of cards". Particularly during construction. And there is virtually no redundancy in many of the components and connections. But when done correctly, they are quick to erect and economic compared to other construction types. I will be curious to discover the cause of the collapse. It sure looks like the end bearing wall either displaced out of plane and the floors fell off their supports, or the supports broke off.

Either way, some hard working people have been injured and possibly killed today. We as engineers must be conscious of this possibility when we are striving to save a few pounds per foot of steel or a few yards of concrete. No one's life is worth saving a few dollars. It is our responsibility to strive to keep preventable failures like this from occuring.

 

[KarlT]

It is my opinion that a major structural collapse like the one in the parking garage is very seldon a result of one simple oversight but rather a result of a series of oversights which build off of eachother and result in a failure.

If precast is designed properly, you would never see this happen. Yes smaller bearing seats are sometimes used but a good precast design engineer will account for tolerances, and all the associated forces to come up with a safe connection design. To say that precast is a poor selection based on building with small bearing seats, then one could also conclude the same thing with steel joist seats on steel beams, or wood trusses on a wall, which relative to their spans have very little bearing.

Precast has been used successfully for many years in buildings that would be more challenging to do out of other materials.

 

[dik]

and may have been used improperly for the construction of the Olympic stadium in Montreal a few decades ago... it has a place.

 

[Rich2001]

Was this cast-in-place structure constructed using the Filigree proprietary system?

http://www.filigreeinc.com/

 

[redhead]

Why the assumption that this was precast. I agree with Rich2001, this looks like a cast-in-situ structure; possibly post-tensioned slabs. The Filigree system was very popular for a while in Atantic City, mostly for standard reinforced flat plate high-rise construction. It is certainly conceivable that it was used here.

 

[SlideRuleEra]

Design of the permanent structure seems to be more or less irrelevant, it was under construction. According to the NY Times, concrete was being placed when the collapase occured.

In all probability the temporay falsework supporting the concrete forms being used gave way leading to a pancake progressive failure.

 

[Bobbalott]

In the some of the pictures I've seen there was a lot of shoring that can be seen. Presumably this is a poured in place job, but for such a tall garage, I doubt it is a straight PIP job.

The slabs in the photos looked rather thin. Unless there are double-tee stems that can't be seen right now, the designers must have relied on some system of post-tensioning to make the 60'+ span that is common in garages.

What can go wrong with post-tensioning? An awful lot. Everything from elastic shortening in green concrete (and slipping off supports) to loss of tension in a lower floor.

 

[JAE]

This brought up a question in my mind. We occasionally see news of a structural collapse, either during construction or after (sometimes long after). In the case of the Hyatt Regency collapse in Kansas City in the 70's, I remember Edward Phrang going around to seminars with a presentation on the NSC's findings. But anymore you don't always get info after the "investigation" is complete.

Is there some vehicle out there, or should there be one, that allows us to review the why's and how's of collapses....to learn from other's mistakes?

 

[Bobbalott]

There are several resources that will address high and low profile structural failures. Two journals that I receive regularly are published by ASCE and often contain information of this nature. Check out the "Practice Periodical on Structural Design and Construction," and the "Journal Of Performance of Constructed Facilities." Sometimes ASCE magazine and the AISC journal also have relevant articles. There are some excellant reports put out by the AF&PA (or one of their subsidiaries) on the big Hurricanes (Hugo, Andrew, Iniki) and I'm sure I've only scratched the surface.

Bobbalot

 

[Lutfi]

I must agree with KarlT.

I also like to remind all that most structures fail at the connections! It is rare that we have other types of failure.

I do not want to jump into conclusion till more facts are available. Those facts will surface when the engineers begin the forensic investigation and work.

 

[KarlT]

Does anyone know of any good web-sites on lessons learned from structural failures. I'm with JAE, I want to learn from what went wrong on these types of jobs so I don't make the same mistakes myself.

 

[ishvaaag]

Lufti...

here most of the failures that make the news are revamping works, or works of foundations. Miscare in the reform or the foundations are the biggest killers here when there's ruin. Some times (revealingly) involves even people that has not even the right to work there, and even people someway related to those that GIVE licenses. Corruption manages to kill... in so many ways.

 

[DTGT2002]

As stated above, the shear wall and end columns for the structure were still standing after the collapse. SO, the connections to them appeared to fail. Whether the structure itself was not suitible for the loads applied, or if the falsework was not sufficient, or 15,000 other things, who can make a judgement and start to blame someone?

From the pictures I have seen, there appeared a mix of precast elements, structural steel and cast in place concrete. I could not tell if the steel was part of the shoring system of the building or not.

Has anyone heard of the final toll? The last article I read noted 3 dead and more missing.

Daniel

 

[bklauba]

The last of the 4 victums was pulled from the rubble about a day after the collapse. It took a while to get there, since he was in a stairwell that was beneath the fallen material.

 

[plasgears]

It would do well for a company to publish a lessons learned in-house publication. At GE, Evendale, OH we had a frank publication that documented mistakes made or designs that did not work. It made good reading for new engineers and older engineers, too.

It would fit in well with the current QS and ISO quality documentations.

 

[jheidt2543]

There are a number of good books regarding forensic engineering with very detailed failure analysis. I've read a few and the things that strike me are:

1. The initiating cause of a failure is not always obvious before hand. I'm thinking of the Kansas City walkway collapse of years ago. I'm not sure many of us would have picked up the problem detail right away. And if memory serves me right, the detail was changed by the fabricator, because the hanger was unbuildable as originally detailed.

2. As was noted above, the analysis of a failure usually finds a host of problems, with one final mistake or unlucky event setting the chain reaction into motion. Sometimes we are just plain lucky that the one "last straw" doesn't show up.

 

[dik]

From the Canadian Consulting Engineer magazine...

Parking garage collapses in Atlantic City
10/31/2003
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A large parking garage that was under construction in Atlantic City, New Jersey collapsed October 30, killing four people and injuring at least 20. The garage had 10 storeys and 2,400 spaces. It was attached to an 18-storey hotel, the Tropicana Casino and Resort.
Five floors of the part of the garage furthest from the hotel fell at around 10.40 a.m. leaving layers of concrete and steel sloping down precariously.
According to reports in Associated Press and the New York Times, witnesses saw survivors dangling from the concrete 20 or 30 feet in the air, while others were caught in the interior or picked their way down scaffolding and tangles of reinforcing rods. A caulker who was working on the building said: "I heard all those floors go. The whole tower shook, like it was a miniature earthquake."
Neither the contractor, Fabi Construction of New Jersey, nor the engineers, DeSimone Consulting Engineers of New York, were commenting on the cause of the collapse. The garage was apparently being constructed with precast concrete slabs overlaid by fresh concrete to form a 10-inch thick deck held in place with bearings. Experts quoted in the New York Times said that it was possible the bracings were damaged or not properly installed and gave way to the weight of new concrete being poured on the deck.