Consequence-based robustness assessment of bridge structures

The aim of this paper is to apply to a steel truss bridge, a methodology that takes into account the consequences of extreme loads on structures, focusing on the influence that the loss of primary elements has on the structural load bearing capacity. In this context, the topic of structural robustness, intended as the capacity of a structure to withstand damages without suffering disproportionate response to the triggering causes while maintaining an assigned level of performance, becomes relevant. In the first part of this study, a procedure for the evaluation of the structural response and robustness of skeletal structures under impact loads is presented and tested in simple structures. In the second part, an application focuses on a case study bridge, the extensively studied I-35W Minneapolis Steel Truss Bridge. The bridge, which has a structural design particularly sensitive to extreme loads, recently collapsed for a series of other reasons, in part still under investigation. The applied method aims, in addition to the robustness assessment, at increasing the collapse resistance of the structure by testing alternative designs. © 2012 Taylor & Francis Group.