Freeway overpass collapses in Oakland, Ca (SF Bay Area) 1

[ehanes75]

Here is the news story:

http://www.sfgate.com/cgi-bin/article.cgi?f=/chronicle/archive/2007/04/29/BAGVOPHQU46.DTL

A gasoline tanker crashed and burned underneath, the resulting fire and heat destroyed the overpass above.

This is really going to screw up my commute to work tomorrow! (and prob for the next few months!!!)

BTW, This is what intense heat can do to steel reinforced concrete structures. Some 9/11 conspiricy theorists should take note.

 

[Qshake]

I wasn't sure that these were concrete structures but I guess most of California is concrete, single column integral with the superstructure....makes for a very non-redundant structure though it isn't likely that a bridge of another type could have faired better.

It's either a testiment to the amount of heat energy or the lack of insulation of the concrete to the rebar. It's a very well known phenomena that the modulus of elasticity degrades wtih increased temperatures.

Frankly if I hadn't seen the fire photos, I would have thought another earthquake shook this bridge. Note the retrofit of the concrete columns on the nearby bridge.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

 

[hokie66]

I think it is a steel structure. Story is ambiguous, but looks like steel box to me. Possibly composite with concrete deck slab.

 

[JStephen]

I found one article that mentions the steel beams were weakened- hard to tell from the pictures, though.

 

[cooperDBM]

The pictures show a concrete slab on steel girder structure. The girders are painted a light green or gray. The steel pier diaphragm is also quite visible. This sort of structure would have no defense against this sort of fire.