The Bridge, the Mine, the Monster Truck

[TheDragoon]

We have aging infrastructure that needs to be replaced, not maintained, it's been maintained beyond it's lifecycle. Build something new and tear down the end of lifecycle equipment.

I largely agree with this, but I would note that sometimes you can refurbish things to help extend the lifecycle. However, that is usually a stop-gap measure as it is more expensive in the long-run to keep pouring money into aging equipment and eventually you'll get to the point where it really is the end of the road.

I would also note that one of the things I have learned through working as a safety engineer is that there is a chance for just about anything to fail despite man's best efforts. Nothing is "safe" -- what you strive for is acceptable risk. Even if you make an effort to add redundancy and margin to your design, there will still be some finite probability that your design could experience multiple failures resulting in the overall failure of the system. It is very possible that this was the sort of thing that this bridge experienced, we'll just have to see what any subsequent investigations can discover. :)