Collapse of part of 5th floor of Huston Garage

[hope9010]

Has anyone heard about a reported partial collapse of the 5th floor of a precast double tee garage in Houston, Texas, in June? If so, does anyone know anything about it, like how old the garage was and whether corrosion was in any way a contributing factor? If not, what was the cause? Any investigation/report on it?

 

[JAE]

http://www.chron.com/news/houston-t...garage-collapses-in-Galleria-area-5523893.php

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[ztengguy]

My money is on snow buildup from plowing

 

[TehMightyEngineer]

Is this going to be Elliot Lake mall all over again?

Maine EIT, Civil/Structural.

 

[hope9010]

It looks like hollow core, not precast double tee. Right? Elliott Lake was also hollow core. Maybe this is a good thing to stay away from for garages. Still, I would like to know what the cause of the collapse was.

 

[hope9010]

...oh, sorry ...the photo is a picture of Eliott Lake.

 

[hope9010]

...so I don't think this is anything like Eliott Lake. But I have no info on the cause of the collapse

 

[jayrod12]

ztengguy,

I think that was complicated by the deicing salts expediting the corrosion process.

 

[hope9010]

Does anyone know anything about the Houston garage partial collapse?

 

[JAE]

Here is photo I copied off the link I posted above (see attached).

It is hard to tell:
1. An "L" shaped spandrel failure? - the photo shows a spandrel (on the left) still there.
2. An interior IT beam corbel failure? A possibility but nothing in the photo about it.
3. A flexural member failure? most failures are connection failures.





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[JAE]

Here's a link to a local site that has several photos - some from the air:

KHOU Link



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[FootNMouth]

I live in houston and through the grapevine I heard that the L-spandrel was never properly attached to the column. The angles were there they were just never welded together. So for the last 20 or so years it was simply being held by friction.

 

[hope9010]

ddudley - Very interesting. I thought from looking at the pictures that I found on the internet, that the spandrel had given way. What you say seems to indicate that may have been the case. Kind of scary that they could forget to complete the angle connections with the weld. Have you heard any other possible cause, such as corrosion?

 

[CELinOttawa]

Are we going to get a good lessons learnt out of this? Does the US have a on equivalent to a Royal Commission? IE: Like in ChCh,

http://canterbury.royalcommission.govt.nz

 

[3DDave]

In Missouri they salt the bridges to death. You can see streams of rust.

In the KHOU pictures I don't see a streak of rust anywhere. Kudos to the guys who put in the next level down. Top level guys - was it a Friday before a three day weekend?

 

[hokie66]

As JAE said, most likely a connection defect, or a missing connection. These things have to be tied together. We get at least one report a year of a precast parking structure collapse. Lessons are learned, by those who want to listen, but then the institutional memory is lost.

 

[FootNMouth]

The connection did not fail it was just never connected. Don't have to worry about deicing salts in Houston. On the rare occasion that it does freeze we just shut everything down.

 

[msquared48]

So with the progressive expansion due to hot weather in the Houston area over the years, assuming the spandrel moved on the support when expanding, but did not when contracting, the spandrel just worked its way off the seat? Seems odd, but maybe, depending on the support restraints, vertical loads, and friction... Perhaps there is more vertical load in the winter to increase the frictional force? Still seems flakey...

Mike McCann, PE, SE (WA)

 

[hope9010]

I have read of a precast system of unusual design that stood up fine for many years and then suddenly the floor collapsed. The investigation indicated that the original design missed an issue that was critical because of the odd ball design. Some other floor structures that were built around the same time also collapsed. Corrosion was not at all an issue.

Lesson: Just because something has performed well over the years does not prove that it is safe and will continue to perform well, or does not need an inspection. If calculations to current Codes indicate a significant structural deficiency with respect to gravity or wind loads, it should most probably be brought up to current codes. Impossible to convince any architect of that though. I know the Houston collapse is a different issue, but it does bring this lesson to mind.