The collapse of the I-35W Bridge in Minneapolis, Minnesota has raised questions regarding the performance and possibly safety of steel truss bridges. The failure investigation indicated that the collapse was due to a design error in the gusset plates used to connect the truss members. The findings also recommend that evaluation of truss connections will be needed, which is a deviation from past practice where only members were considered. Gusset plates connect individual steel truss bridge members together at a node. In 10% of the 200,000 steel bridges in US in 2008, failure of a single truss or connection could lead to collapse. Regular inspection and load rating are essential for the safe operation and maintenance of these bridges. The Minneapolis I-35 Bridge collapse was the first gusset failure where a design flaw was implicated. Load rating gusset plates is a significant challenge given the number of connections and the complexity of accurately evaluating each one. The majority of research on gusset plate strength is from small-scale connections. More refined techniques are needed to conduct high-fidelity capacity evaluations. Finite element analysis (FEA) is widely used in structural engineering. Using FEA in gusset plate evaluation presents challenges due to the connections’ large-scale, high degree of geometric variability and complex load paths.
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