Seismic Fragility Analysis Of RC Frame Structure With Infills

Human life and property safety was threated by global earthquake-prone seriously,and RC frame structure was used widely in China,the impact of the infills in the RC structure can not be ignored,therefore,the seismic fragility analysis of the infilled RC frame which is important for preventing the frame structure damage or even collapse under the earthquake was carried out.The following studies include:(1)The analysis program OpenSees was introduced,and the selection of the element in the finite element model of the structure and the determination of the parameters of the material model was introduced.The spring element was used to simulate the plastic hinge of the frame structure was highlighted,and the modified Ibarra-Medina-Krawinkler deteriorate model was used as its material model,at the same time,the truss unit was used to simulate the interaction between the filling wall and the main frame was highlighted,and the Ibarra-Medina-Krawinkler deteriorate model was used as its material model.(2)Two single-storey single-span frame models were established by using the unit model and material model of OpenSees which was mentioned.The whole process of low-cycle repeated loading was simulated by software and compared with the original experimental structure,then the accuracy of the fine model which used to simulate the nonlinear performance of the infilled RC frame structure was verified.(3)Based on the unit model and material model described above,four 7-storey,3-span planar RC frame were established.Through the IDA analysis of these four frames,the IDA curve and the fragility curve of the structure was obtained.By comparing the fragility curves of the IO state,the LS state and the CP state,the following conclusions was found:in the case of the new type wall material was used in the structure,infilled wall which was seen as the first anti-seismic line of the structure was beneficial when the seismic intensity was small,however,when the seismic intensity is large,the infilled wall was destroyed fastly,and the damaged wall may reduce the anti-collapse performance of the structure.It is also found that the infilled frame with solid clay brick has the best seismic performance in the four models,in the situation of the new type wall material was used in the structure,the role of infilled wall as the first anti-seismic line should not be considered as the banned traditional wall material,and been estimated too optimistically.