Improved seismic response of multi-span bridges retrofitted with compound restrainers

This numerical study aims to evaluate the seismic performance of bridgesretrotted with a new compound restrainer, and the sensitivity of their responses to likelychanges in the characteristics of the restrainer's components. the compound restrainer wasintroduced as a retrot tool for improving the seismic response of multi-span bridges interms of forces and displacements. the compound restrainer is mechanically an assemblyof several elastic and plastic springs. to this end, real 2-span and 3-span simply supportedplate girder bridges have been used for the case study. nonlinear time history analyses ofdetailed three-dimensional models have been performed under seismic excitations in orderto assess the performance of the existing and retrotted bridges restrained by conventionaland compound restrainers, numerically. the results show that the compound restrainer isvery sensitive to the characteristics of its components. moreover, while past earthquakeshave shown the deciencies of the conventional restrainers, the compound restrainer seemsto be successful in dissipating hysteresis energy in bridges, as well as in reducing the internalforces imposed on the substructures.