A New Seismic Performance Upgrading Method for Existing Steel Bridges Using BRBs

A new seismic performance upgrading method for existing steel bridges using buckling-restrained braces (BRBs) is presented. Contrary to the conventional practice of BRBs for retrofitting steel bridges, the proposed method is to keep using the existing bracing members without replacing and to reform them to energy-dissipating members at their sites. The present paper deals with a series of background experiments, including (1) performance tests of isolated BRBs with H-section core members and (2) performance tests of rigidly- connected plane steel truss models with bare or “BRBed” H-section diagonal bracing members. Furthermore a pseudo-dynamic test is performed to determine the demand of a prototype steel truss structure subjected to severe earthquakes.