Fragility Analysis Of Long-Span Prestressed Concrete Continuouss Beam Bridge In High-Speed Railways

In recent years, earthquakes have broken up more frequently and several major earthquakes have caused serious damages. Researches on Performance-Based Earthquake Engineering has occupied more and more attention. Performance-Based Earthquake Engineering involves Seismic Hazard Analysis, Seismic Demand Analysis, Seismic capacity analysis, Damage assessment and decision-making, of which fragility analysis is the most important part and affect the accuracy of the results.By now, researches on fragility analysis in our country has focused on structures and Highway Bridges, while there is few research on Railway Bridge especially on long-span prestressed concrete continuous beam bridge used in high-speed railway. Based on the China Railway Corporation’s Technology Research Plan, taking a typical long-span prestressed concrete continuous beam bridge for example, the fragility curves of the bridge is plotted in this paper by the method of IDA. The outline of the dissertation is as follows:1) The method of fragility analysis, and the basic framework and process of Incremental Dynamic Analysis was summarized;2) Taking a long-span prestressed concrete continuous beam bridge for example, model with slab ballastless track and model without slab ballastless track were established. And the process was described in detail.3) According to the analysis result, damage index and damage state of bridge are determined based on the stress and strain of materials.4) 20 natural seismic ground motion records are selected in this analysis. Fragility curves of model with slab ballastless track and without slab ballastless track are plotted through the IDA method, and a conclusion was drawn:the dynamic characteristics of bridge was changed, the seismic response of bridge was reduced and the performance of bridge was improved by slab ballastless track.5) Whether concern the damage connection of different structural components, different fragility curves of overall structure were plotted. The influence of epistemic uncertainty on fragility curves is discussed in this paper.