The Application Of Capacity Spectrum Method Of Considering Soil-Structure Interaction In The Bridge Seismic Performance Evaluation

Nonlinear characteristics of pile foundation and subsoil have an important influence onseismic performance for bridges. When the interaction of soil-structure is considered, relevantresearch on seismic performance has become a research focus in bridge seismic fields. Thisstudy based on the characteristics of railway bridges, both theoretical analysis and numericalsimulation were used simultaneously, in order to study nonlinear behavior of pile piers underthe interaction of soil-structure. The main research contents and results are as follows:（1）Through various of researches on static pushover model, the nonlinear pushovermodel has been proposed under the consideration of interaction for soil-structure. In thismodel, nonlinear characteristics of pile foundation and subsoil could be consideredsimultaneously, and interaction between structure and subsoil also be simulated completelyunder the effect of earthquakes.（2）According to the nonlinear static calculation model of pile foundation，differentfactors which influenced on bearing capacity and deformation capacity of the pile pier, havebeen systematically researched, such as pile longitudinal reinforcement ratio, stirrup ratio, soilparameters, pier height and loading mode. Thus the development and distribution of pileplastic hinge have been presented simultaneously.（3）Reduction in demand spectrum was studied on the consideration of interaction forsoil-structure. Meanwhile, various spectrum demand reduction methods were comparedanalyzed when pile-soil interaction characteristics to be considered synchronously. Studieshave shown that both vidic and xilin reduction models were more suited to reduction indemand spectrum under the interaction of soil-structure.（4）Based on the comparable analyzed of capacity spectrum method, modified capacityspectrum method, displacement coefficient method and performance point trajectory methodin ATC-40, methods have been proposed to solve the performance point according to researchachievements for reference[65].（5）Finally, relevant norms and research achievements have been fully absorbed, andthe characteristics that bridge pier top displacement was significantly increased has beentaken into account comprehensively. Therefore, with the pier top displacement angle as adamage index, the bridge seismic performance evaluation was ultimately proposed anddetermined. Since the index made more stringent restrictions on the pier pier top displacement,thus it could be used to guide the design for bridges.