Over the weekend the local news stations were carrying a story about a bridge failure in Kentucky. In light of that story, it seems like a good time to share some research I’ve been doing into bridge failure statistics.
It’s tough to find any statistics on bridge failures. Surprisingly, there’s no national database on bridge failures. The best I was able to find is an database that New York State DOT keeps on bridge failures. It basically includes entries for whatever they have heard about either in the media or what was volunteered by other state DOTs. It’s nowhere near comprehensive on the national level, but presumably it would be pretty accurate for New York since they would be well informed about their own state.
Before I share the statistics, there are a couple of things to keep in mind:
- This includes all bridges, not just the big ones that end up in the national media. Most bridges are small structures and not of interest to anyone outside the immediate area they are located in.
- Failure doesn’t necessarily mean going down in a spectacular cloud of dust. A structure failure is anything that keeps it from being used in the way it was intended. And now for the statistics…….
The biggest number of failures by far are caused by bridge hydraulics. This means anything related to water and includes things like bridge scour, being clogged by ice or debris, approach road wash-outs, and just being pushed over by water. Hydraulics is my specialty area and I’ll cover some of those in more depth in later posts. The second greatest is collision. I’m not entirely clear about this label, but I assume it means collisions by boats as well as collisions by trucks. The overload and earthquake labels seem self-explanatory. I assume fire refers to wooden bridges, but I do know of at least once instance where a tanker truck blew up under an interstate bridge and melted the beams so badly the entire structure had to be replaced. (It does occasionally happen outside of Michael Bey movies.)
I’m going to do a more in-depth analysis of the statistics in my next post so you folks who got your fill here can skip it.