Seismic Response Analysis of Long Span Cable-stayed Bridge by Response Spectrum Method

Based on response spectrum method, the seismic behavior of a long span cable-stayed bridge is investigated through three dimensional finite element model established by ANSYS. By calculating the cumulative effective mass factors of the bridge, the minimum number of modes used for modal superposition analysis is obtained. Design acceleration response spectrums under two probabilities are used in the analysis. The response spectrums are input in the bridge longitudinal direction, vertical direction, transverse direction and combined horizontal and vertical directions. Displacements and internal forces results show that vertical component of the ground motion greatly influences the response of the bridge and there is significant difference between the results of the two probabilities.