Steel truss bridges are particularly vulnerable to progressive collapse, which is understood as the process by which an initial local damage propagates to the rest of the bridge.
There are many examples of collapse occurring in this type of bridge. For example:
- The Quebec Bridge collapsed in 1907 during construction due to buckling of a few bars.
- A span of the I-5 bridge over the Skagit River collapsed in 2013 due to the impact of a truck on the overhead truss.
- The I-35W bridge in Minneapolis collapsed in 2007 due to the propagation of a local failure. In the latter case, the failure of a single gusset plate caused a domino effect, resulting in the collapse of the entire bridge.
To reduce the vulnerability of this type of structure, it is important to assess its robustness. With this in mind, Building Resilient has tested a 21 m bridge span in the ICITECH-UPV laboratories.
The key to avoid failure propagation is to define adequate inspection and monitoring protocols.