Seismic Fragility Analysis Of Frame Structures With Varied Installation Height Of Transfer Storey

At present, the research of the reinforced concrete frame structure with transfer storey has been perfect; however the safety probability level of this form of structure is uncertainty.This paper consider the influence of level of transfer storey on seismic behavior of reinforced concrete frame structure, It is necessary to establish two transfer storey which in the fifth storey and two storey The results of3D model’s modal analysis and seismic elastic analysis with ANSYS finite element software demonstrate that with the increase of seismic acceleration, the grow rate of storey drift ratios(SDR) of high-level transfer storey is quicker than low-level transfer storey, and the difference of two kind model also increase. The curves of SDR show the SDR of transfer floor in the high-level transfer storey model mutate because of the stiffness change of up and down floor. This phenomenon doesn’t emerge in low-level transfer storey model. In the chapter four SAP2000analyze the seismic elastic-plastic time-history analysis of two frames. The fragility curves which the peak ground acceleration for the X-coordinate and the probability of story drift ratio over allow story drift index for Y-coordinate are drawn. The main conclusion as follows:(1) With the increasing of the seismic peak acceleration, failure probability of structure increased.(2) When PGA equals0.05g and0.1g, the structures with high&low-level transfer storey are intact. When PGA equals0.2g and0.3g, the structure with high&low-level transfer storey is at the state of slight damage. When PGA is between0.4g and0.6g, the structure with low-level transfer storey is at the state of moderate damage; however when PGA equals0.4g and0.5g, the structure with low-level transfer storey is at the state of moderate damage, which is at the state of severe damage when PGA equals0.6g. When PGA equals0.7g and0.8g, both of them are at the state of severe damage.(3) The installation height of the transfer storey has little effect on the occurrence probability of minor damage and moderate damage. However, with the increasing of PGA, the failure probability of the structure with high-level transfer storey is significantly higher than the structure with low-level transfer storey at the state of severe damage and collapse.(4) The seismic damage index of the structure with high-level transfer storey is slightly higher than the structure with low-level transfer storey. When the value of PGA is larger, what the height of transfer storey increases will improve the gradation of seismic damage.