fifeboy fifeboy:
DrCaleb DrCaleb:
Canadian_Mind Canadian_Mind:
Not sure why a bridge would fail like this. But this is why we should always have a primary and a secondary highway.
There are a number of ways. If the metals weren't properly accounted for temperature variance - falling temps could have meant that the wires would shrink more than expected. The same with the supports in the ground - one side may be differing metals than the other and cold means one contracts faster than the other. The decking may also expand and contract at a different rate than the structure the decking is held up by.
That's why bridges usually have those interlocking metal forks called 'expansion joints' that let the bridge flex in different temperatures.

I always thought that engineers were hired to prevent this. Someone needs their licence reviewed!
I recall back in the 80's that silicon valley had so much coke being snorted, that a number of newfangled 'anti lock' and 'fuel injection' systems for cars were leaving people without brakes and engine power suddenly because the silicon dies were cracking under heat stress. One of the fundamental things we calculate when designing the dies!
Not only does someone need their license reviewed, but so do the supervising engineers that signed off on it! Unless of course, we are seeing something no one could have anticipated or had seen before, like at Tachoma Narrows.