3D Seismic Vulnerability Analysis of Bridge Structural Components Based on Reliability

In order to evaluate the near-field seismic performance of bridge structures, a three-dimensional (3D) seismic vulnerability analysis process for bridge components is established. Based on the reliability theory of engineering structures, 3D failure surfaces of the components are used to characterize the damage status of pier columns and bearing components, and the damage state equation containing multiple independent damage indices is regarded as the damage index for the 3D seismic vulnerability analysis. In light of the existing research on the bending and shearing failure surfaces of piers, damage state equations for piers with bending failure and shear failure and for bearings with relative displacements are built. On this basis, the criteria for 3D seismic damage of pier columns and bearings are established, and quantitative methods for calculating the damage in different damage states are presented. The final calculation and analysis of the 3D seismic vulnerability of bridge components are accomplished in accordance with the bridge seismic design codes in various countries and the reliability theory of engineering structures. A simplified validation of one-dimensional seismic vulnerability shows that the proposed method can be applied to the seismic vulnerability analysis of bridge structures, with a maximum probability deviation of less than 4% from the traditional probabilistic seismic demand analysis (PSDA) method.