Analysis of Seismic Damage Characteristics and Seismic Vulnerability of Bridges in Wenchuan Earthquake

Based on the mathematical statistics method, the seismic damage data of railway and highway system bridges in Wenchuan earthquake area are statistically analyzed, and the characteristics of damage distribution and the change of damage grade of two kinds of system beam bridges are obtained. The results show that the failure curve of the railway system is "X", and the failure curve of the highway system bridge is a "X" shape. Under the same earthquake action, the seismic damage of the highway system bridge is larger than that of the railway system bridge, and the seismic performance of the highway system bridge is worse than that of the railway system bridge. Based on the statistics of bridge seismic damage, the vulnerability matrix of two kinds of system girder bridges under different intensity earthquakes is obtained. Based on the fitting of the beta distribution function, the seismic fragility curves and distribution function fitting parameters of two kinds of system girder bridges are obtained. The results show that the two kinds of beam bridges under the low intensity earthquake are all in good condition. In the high intensity earthquake, the railway bridge is mainly medium damage, and the highway bridge is mainly damaged and destroyed. The research results can provide reference for earthquake disaster prediction and earthquake disaster loss assessment in earthquake stricken areas.