Seismic Vulnerability Analysis Of Continuous Rigid Frame Bridge Based On IDA Method

With the development of Southwest China in the west,the bridge construction is particularly important in the high mountains and deep valleys of Southwest China.Continuous rigid frame bridge,because of its good mechanical characteristics and the advantages of easy maintenance,so the use frequency is more.But at present,the damage state of continuous rigid frame bridge under earthquake is still in the primary stage,so this paper introduces the vulnerability analysis theory based on IDA method.This method can quantify the seismic performance of the structure in the way of probability through the incremental dynamic method,and describe the relationship between the seismic intensity and the damage degree of the structure from a macro point of view.The seismic vulnerability analysis of bridges has important application value for predicting the seismic performance of structures,carrying out the seismic design of structures,strengthening and maintenance decisions.In this paper,a multi span continuous rigid frame bridge(with tie beam and double limb thin-walled pier)is taken as an engineering example,and the modeling analysis of multi span continuous rigid frame bridge is carried out by using Midas civil finite element analysis software,considering the bridge analysis in both horizontal and vertical directions.By referring to the same type of research literature at home and abroad,the displacement ductility ratio is selected as the analysis index to divide the damage indexes of bridge members at all levels under earthquake action.By enlarging or reducing the peak ground acceleration PGA,the seismic response data samples of bridges at various strength levels are analyzed,and the vulnerability function of damage transcendence probability at all levels is obtained by processing,and the damage transcendence probability at various levels is calculated Finally,the vulnerability curve of the whole bridge system is calculated by using the first-order boundary method,and the conclusion is drawn.In the fifth chapter,through the establishment of a multi span continuous rigid frame bridge model with thin-walled piers without tie beams,the vulnerability analysis of pier components and the vulnerability analysis of the whole bridge system are carried out in the same way.Finally,through the comparison of the two working conditions,the influence of the arrangement of tie beams on the damage probability of the whole bridge is analyzed.