Feasibility Analysis Of Relaxation Of Interstory Drift And Height Limit Of RC Shear Wall Structure In High Intensity Area

The current code ensures the safety of the structure by controlling the inter-story drift of the structure under horizontal load.However,in some high intensity areas,in order to meet the limit requirements,the designed structure has too many vertical members or too large section size,which leads to the waste of building space and material resources.In addition,the different input seismic waves in the dynamic time-history analysis of the structure may lead to a great difference in the response of the structure,resulting in a lack of accuracy.In order to judge the feasibility of relaxing the inter-story drift and height limit of RC shear wall structure in high intensity area,in this paper,128 seismic waves are collected from Kashgar,Xinjiang(8.5 seismic fortification intensity)and 6 shear wall structures with different interstory drifts and heights are analyzed based on the local actual projects.The main contents and conclusions of this paper are as follows:(1)Through the analysis of the seismic wave in Kashgar,Xinjiang,the law of its spectral characteristics is obtained.128 seismic waves with different earthquake magnitudes collected from Xinjiang strong motion observation net are normalized by peak acceleration to establish the seismic wave database in this paper.By comparing the error with the design response spectrum of the two codes,this paper gives some suggestions on wave selection for shear wall structures with different periods under a specific site.(2)Through the analysis of the seismic wave of different magnitudes at the same station,the law of its characteristics is obtained.By calculating the response spectra of seismic waves of different magnitudes under 21 stations and comparing the elasto-plastic responses of shear wall structure caused by these seismic waves under large earthquake.The conclusions are as follows: The greater earthquake magnitude of seismic wave is,the greater acceleration spectrum,velocity spectrum and displacement spectrum are(T>0.5s),and the greater the damage to shear wall structure is.(3)Establishing structural model to analyze its performance with seismic waves which are selected by the code design response spectrum.Combined with the current code,this paper designs 6 shear wall structure models with different inter-story drifts(1/1000,1/800,1/500)and heights(80m,120m),based on a practical project in Kashgar,Xinjiang.7 seismic waves are selected from the database based on the code design response spectrum to analyze the elastoplastic responses of 6 shear wall structure models under 8.5 degree large earthquake.The conclusions are as follows: 6 shear wall structure models have good safety under large earthquake.In this paper,it is suggested that for the shear wall structure in the high intensity area,the elastic inter-story drift should be relaxed to 1/500 and the height limit should be relaxed to 120 m.(4)Secleting the most unfavorable design seismic waves to analyze the performance of structure models under large earthquake.By using the method of selecting the most unfavorable design seismic waves proposed in this paper,7 seismic waves that may produce the maximum response to the structure are secleted from the database to analyze 6 shear wall structure models’ elastic-plastic response,which is compared with the response under 7 seismic waves selected by the code design response spectrum.The conclusions are as follows: Taking the base shear force and overturning moment of elastic time history analysis under large earthquake as the basis for selecting the most unfavorable seismic wave is reasonable and effective,6 structure models still have good performance under the most unfavorable seismic waves,which proves that it is feasible to relax the inter-story drift and height limit.