Application of Energy Absorbing Connecters to Seismic Retrofitting of Existing Girder Bridges

Abstract

Energy absorbing connecters consisting of shoes and steel bellows have been investigated by the authors as one of economical seismic design methods for a system of new steel bridge girders supported by piers. The shoes are designed to collapse as fuse members intentionally in this method in order to decrease inertia forces caused by a strong earthquake. The inertia forces and response displacement of the girders after the collapse of the shoes are restrained for the effect of energy absorption due to plastic deformations of the steel bellows. In this paperinvestiga ted is the method in which the connecters are applied to the seismic design of existing steel bridge girders. Firstly, a numerical simulation method is explained to estimate the seismic behavior of a bridge system. Secondly, the necessary conditions are discussed to apply the connecters to existing steel girder bridges. Thirdly, a trial design is carried out to investigate the seismic retrofitting method of medium-span girder bridges using the connecters. Validity of the connecters is finally confirmed by the nonlinear seismic response analysis using results of the trial design.