Analysis of Seismic Fragility and Recoverability of Long-Span Cable-Stayed Bridge

To study the seismic capacity of the main tower of cable-stayed bridge under earthquake and evaluate its seismic recoverability, the structural dynamic calculation model was established by the finite element analysis program SPA2000 based on a single-column long-span concrete cable-stayed bridge, the seismic response of the transverse cable-stayed bridge was analyzed by incremental dynamic analysis (IDA). The moment-curvature curves of the tower key sections were studied and the curvature damages were calibrated by analysis software X-TRACT, then the data from IDA analysis were processed, and the seismic vulnerability curve of each key sections of the main tower was obtained, and the vulnerable part of the main tower and its evolution law were determined. Based on the concept of recoverability, the seismic restorability analysis of the structure was carried out. The results show that under the action of transverse seismic, the bottom section of the tower is the vulnerable section. When the action of seismic intensities are 0.150g and 0.271g, its own seismic capacity decrease from 80.6% to 46.7%, with the increase of seismic intensity, the bridge’s seismic reserve capacity decrease.