In all these seemingly unrelated disasters, ships or barges deviated from shipping channels, striking the bridge and causing the collapse. In the last 25 years, straying vessels caused five high-profile U.S. bridge collapses, causing 105 deaths. So what can engineers do?
A recent study of collapsed bridges found that engineers designed piers adjacent to shipping channels that were capable of withstanding a strong collision, sometimes a collision much more forceful than they were ever likely to experience. However, other piers were often weaker in design and unable to survive. The operating assumption apparently is that ships wont leave their regulated path. This is a mistake. Fortunately, there are a number of ways public agencies can mitigate potential bridge/ship collisions, including: