Study On Seismic Vulnerability Of Reinforced Concrete Frame Structure Considering Ground Motion Characteristics

In recent years,with the significant increase of earthquake frequency,the collapse resistance of structures under the influence of rare earthquakes has attracted the attention of many researchers.However,at present,researches on the collapse resistance of Reinforced Concrete(RC)frame structures are mostly based on non-pulse-type ground motions,while researches on the impact of ground motions with velocity pulses are still in the primary stage.Because this kind of earthquake occurs with relatively high energy velocity pulses,which can be released in a relatively short time,It is easy to cause serious damage to structural system,so it is of great significance to study the seismic behavior of reinforced concrete frame structure with velocity pulse and its effect on seismic performance to improve the resistance of structure to pulsed seismic behavior.Based on this,this paper mainly carries out the following research:(1)The pulse index PI proposed by Baker based on wavelet analysis was used to identify velocity pulsed ground motions.60 near-field non-pulsed ground motions,60 near-field pulsed ground motions and 50 far-field pulsed ground motions were identified from the PEER database.The differences of amplitude,response spectrum and duration of pulse-type ground motion in far and near field and non-pulse-type ground motion in near field are compared and analyzed.(2)OpenSees analysis software is used to simulate and analyze the whole RC frame structure and RC frame column samples of Tsinghua University,which proves the rationality of the modeling method in this paper.From identifying the near field of the pulse type ground motion,near field pulse type ground motion and the far field pulse type selected 10 of the ground motion,and to one common six coats of RC frame structure of three spans incremental dynamic analysis(IDA),and then obtain the structure failure probability formula,mapped the frame structure under the limit state of seismic vulnerability curve,The seismic performance of RC frame structures subjected to the above three kinds of ground motions and the collapse margin ratio(CMR)of structures subjected to different kinds of ground motions are studied.(3)On the basis of three kinds of ground motion studies,the seismic vulnerability of RC structures under different axial compression ratio,concrete strength grade and floor lateral stiffness ratio is studied,the influence of the above factors on the seismic performance of structures is analyzed,and the variation rule of CMR under the influence of different structural parameters is obtained.