Seismic Vulnerability Analysis And Strengthening Of Reinforced Concrete Hollow High-pier Bridges

As an important transportation, bridge engineering is related to people’s livelihood in lifeline engineering. Once suffered from the earthquake, it is difficult to rescue and causes huge economic losses. Therefore, the study of seismic damage and damage mechanism of bridge structure is significant in terms of establishing the seismic resistant concept and method of bridge structures.The main content of this study is the analysis of the seismic elasto-plastic response by using finite element analysis method, during it, nonlinear seismic response of the long-span continuous rigid bridge structure system and single pier is researched to study the characteristics and mechanism of nonlinear seismic response of high-pier and long-span rigid bridge, the seismic performance evaluation of the circular hollow high-pier and long-span bridge before and after the reinforced is discussed. The details are as follows:(1) The elasto-plastic earthquake response analysis model of continuous rigid frame bridge with circular hollow high-pier is established and analyzed by using OpenSees (Open System for Earthquake Engineering Simulation), and then the vulnerability of the bridge structure and components are formed by using the analysis results. During the analysis, the probability damage area of each pier and support is found. Finally, Based on the first-order and second-order boundary method, the damage probability of bridge system forms and the seismic performance is evaluated.(2)After the vulnerability analysis of the whole bridge structure under the earthquake, the incremental dynamic analysis of the components is carried out. During this analysis, as the damage index, the sectional curvature is calculated firstly, and then, fragility curves of the components is formed. Finally, the bridge components which are easy to break are obtained.(3)When the bridge components which are easy to break under the earthquake are obtained, the method of strengthened pier with Fiber Reinforced Plastics(FRP) is put forward. the finite element model of the structure before and after reinforcement is established. By using the finite element software (ABAQUS), seismic response analysis is done. Finally, seismic performance evaluation before and after reinforcement is predicted.