The Failure Mechanism Concept – An Innovative ULS Design Approach

The Failure Mechanism Concept (FMC) is an innovative plastic design approach which encourages designers to investigate probable failure mechanisms and intentionally define the weakest link along primary load paths. The FMC is very useful for Integral Bridges (structures without bearings and expansion joints), but even for conventional bridges the method offers new opportunities to design structures with lower construction and maintenance costs, improved durability, and a higher safety margin against failure. The over 1 km long Deh Cho Bridge crossing the Mackenzie River in Canada (see Figure 1) has been designed using the FMC design approach. As a result, a continuous superstructure was achieved thereby avoiding two costly expansion joints in the main span.