Evaluation of Inelastic Seismic Responses of Multi-Degree-of-Freedom Bridge Structures using Capacity Spectrum Method

To evaluate inelastic seismic responses of multi-degree-of-freedom (MDOF) bridge structures, the capacity spectrum method (CSM) incorporating the equivalent single-degree-of-freedom (ESDOF) method is presented. Application of the CSM incorporating the ESDOF method is illustrated by example analysis for symmetric and asymmetric bridge structures. To investigate an accuracy of the CSM, the maximum displacements estimated by the CSM are compared to those by inelastic time history analysis for several artificial earthquakes. The results show that the CSM provided conservative estimates of the maximum displacements for the symmetric and asymmetric bridge structures, and the trend of conservative estimates of the asymmetric bridge structures was significantly larger than that of the symmetric bridge structure.