Thursday, August 02, 2007

Bridge Collapse

The bridge collapse in Minneapolis is a horrible calamity.
As I was watching the TV coverage of the collapse and the questions about its cause: construction work, age, terrorism, I thought of the times when I have been on the Kansas Expressway Bridge over James River Freeway waiting for the light to turn green so I could head east on James River. There have been times I could have sworn I felt that bridge shake.

I remember somewhere reading that bridges were designed to "float" due to variations in ground temperature, water density, freeze and thaw cycles.
I wonder if the compression of traffic into two lanes, the bumper to bumper traffic and the vibrations caused by the cars and trucks hastened the collapse of the bridge.

No comments: