August 2nd marks the 15th anniversary of the collapse of the I-35W Bridge, spanning the Mississippi River near St. Anthony’s Falls in Minneapolis, MN. On this day in 2007, during the latter portion of rush hour, a gusset plate in one of the truss spans gave out under the weight of gravel and concrete, causing the entire bridge to collapse. 13 people died and hundreds were injured. The bridge disaster marked the beginning of an era where engineers and highway agencies in the United States and around the world began to scrutinize the bridge designs and inspect the structures very carefully, proactively demolishing bridges that had the potential to collapse.
However the collapse has led to questions of not only how the bridges are designed but also how the bridges are being maintained and how many years should a bridge be in service. Many of these bridges were built in the 1950s, 60s and even 70s, all of which in mass quantities and part of the expansion of the freeways in America and Europe. While these bridges are modern, these bridges are at risk of collapse. Excessive weight, combined with wear and tear, as well as rust and corrosion have brought the bridges at risk.
American Public TV Channel PBS did a documentary entitled “Why Bridges Collapse?” in 2020. Using this bridge as well as other bridge examples, such as the Morandi Bridge in Genoa, Italy, the Hammersmith Flyover in London, and the Silver Bridge in Ohio, this documentary features the stories of each of the bridges and how they collapsed or came even close to it. There are several interviews with bridge experts, historians, engineers and even prosecutors providing details of the stories of what happened, all of them have one common message: these bridges need to be cared for as often and as proactively as possible to avoid further disasters like the ones mentioned in the film. This documentary is part of the Nova series and is one where future bridge builders must see in order to understand how bridges work and how important it is to maintain them, as often as possible. Remember: There is no such thing as a bridge with a 100-year free maintenance guarantee. When looking at these modern bridges and comparing them to what is being built, there never was one to begin with.
Enjoy the film documentary. 🙂