Redundancy Evaluation of Existing Bridges

The redundancy of an existing bridge can only be correctly assessed by considering the full superstructure as a single entity. Any formulation based on the analysis of bridge components as separate units will lead to erroneous results. With the implementation of load and resistance factor design (LRFD) approach into the AASHTO Bridge Design Specification procedures are available that account, to a limited degree, for load redistribution in some bridges. The scope of this paper is much broader in that 3D finite element analysis will be used to model bridge behavior, and a dependable prediction of bridge redundancy when damage occurs to various members is proposed. Such information will assist in establishing bridge inspection and repair strategies. A numerical example is presented for the purpose of illustration.