Application of capacity spectrum method in bridge seismic evaluation

For the seismic evaluation of bridges,the deformation ductility is one of the performance indices.Based on pushover analysis,the capacity spectrum method is suitable for calculating the inelastic seismic response.The theory and application of this method is introduced,and the capacity spectrum method based on elasto-plastic response spectrum for determining the performance point without iteration is explained.Comparison between the method and the nonlinear time history analysis is processed with an example.The inelastic demand spectrum is established according to the seismic design spectrum,and seismic evaluation of the bridge is accomplished based on the different basic seismic intensities and types of ground soil profiles.The results indicate that this method has creditable precision.In addition,the nonlinear seismic response can be achieved based on the seismic design spectrum.