[jeffers]

No, on closer inspection, the mainspan piers appear to be intact.

Heat will expand steel, but good design takes this into account. An expanding deck, for example is not permitted to shift verticals out of plumb.

Something else did that here:



Either the diagonals between the kingposts failed, allowing them to deflect sideways under load, or else the next pier/truss system in the sidespan (behind the word "kingpost" in green) failed, transferring considerable gravity load to the mainspan pier/truss system and it couldn't take it.

Thanks to Straight Vermonter for the underlay image and the notion of sidespan pier failure.

[Lijahsbubbe]

I defer to your expertise.

News talking about traffic tomorrow. This is going to be a mess, to say the least.

[Southack]

There was a fatal bridge collapse in Texas in September of 2001 when a tow boat captain rammed a string of barges into a bridge.

Here’s a list of other recent bridge collpases: http://www.iht.com/articles/ap/2007/08/02/america/NA-GEN-US-Bridge-Collapse-History.php

[Lijahsbubbe]

According to WCCO, CNN reporting water erosion caused piling (?) to fail.

[exit82]

Jeffers, can you orient me as to the direction of view in post 1615, and the two sides of the bridge in the picture on post 1507?

[idkfa]

Close up of that area. Larger pics here
http://flickr.com/photos/s4xton/981247474/in/set-72157601157770382/

[UCANSEE2]

Hopefully you have already seen this, but just in case.

http://www.liveleak.com/view?i=1ab_1186054443&p=1