Fundamental consideration on the redundancy of a continuous multiple plate girder bridge based on nonlinear finite element analysis

Abstract

After the collapse of the I-35W highway bridge in 2007, the importance of redundancy of bridges has been recognized. Although the multi-girder bridges are generally classified as redundant structure, it is not trivial which member contributes the redundancy. As for composite girder bridges, decks and bracing systems have been found to be effective in distributing the load after the failure of the steel girder. For non-composite girder bridges, the contribution of decks is not clear since the composite action between decks and main girders has not been clarified. This study evaluates the contribution to the redundancy of cross beams and sway bracings through a series of nonlinear finite element analyses. As a result, cross beams and sway bracings are found to be alternate load paths.