Analysis Of Damper Parameter And Seismic Vulnerability Of Long-Span Cable-Stayed Bridge

Long-span cable stayed bridge is an irregular bridge in the traffic life line. In order to reduce the earthquake damage, many researchers will add the isolation device in projects, which extends the structure period, consumes seismic energy and protects the structure of the bridge from destruction. Seismic vulnerability of the bridge structure responses outcross probability beyond a predetermined state of destruction at different intensity ground motions. Seismic fragility curve is the most intuitive form of expression.It reflects the relationship between damage probability of bridges and the intensity of vibration, which is a very important means of bridge risk assessment. So it is necessary to carry out the research work on the vulnerability of the seismic isolation cable stayed bridge. This paper carries on the analysis of damper parameters and seismic fragility of the Kekedala Bridge. The main contents are as follows:1. This paper first establishes the finite element model of the cable-stayed bridge and gets the basic cycle modes by the analysis of the dynamic characteristic. Then getting the response of structure with viscous dampers in the longitudinal bridge by nonlinear time history analysis, to find the best damper coefficient C and exponent ζ, this papers establishes three-dimensional equation of main girder span displacement, bottom shear, moment and damper damping force by using Matlab surface fitting and constructs effect evaluation function. Final this paper sets steel dampers to the auxiliary pier, pier transition and pylon in the transverse bridge and obtains the optimal solution in different positions by standardized data of seismic response amount of critical sections using mean method.2. Considering the structure under the condition of uncertainty, reinforced elastic modulus, steel yield strength, elastic modulus of concrete are selected as representative values. In order to get "seismic waves-structure sample" set, this paper takes random combination of seismic wave and the bridge structure which are obtained by Latin hypercube sampling. Then this paper gets seismic response values of key member for each small sample using nonlinear time history analysis, which is obtained by seismic waves AM in finite element model of different samples.3. The different damage indicators are put forward for different components of cable-stayed bridge and the fragility curves of are each member and section in the cable-stayed bridge by using the method of proficiency requirement ratio. The section of pylon which is most likely to damage can be obtained by comparing damage probability of each member and cross-section. And comparison of the vulnerability of each member with setting dampers and no dampers.Final the application of reliability theory are used to establish fragility curves for bridge system...