Research On The Drift Limits Of Frame-supported Shear Wall Structure Under Seismic Load

In the structural design of high-rise buildings,the structural stiffness is often increased in order to meet the requirements of the code for the elastic story drift limits,resulting in an increase in the amount of building materials and seismic response of structures,which causes adverse effects on structures.As a result,the Guangdong technical specification for concrete structures of tall building relaxs the elastic story drift limits of the structure,but the specific value is lack of sufficient theoretical support.Therefore,it is necessary to carry out in-depth research on the rationality of the limit of elastic story drift under earthquakes in the current code.The anti-seismic system of buildings in the United States is the earliest,and a set of relatively complete seismic design codes and standard system has been formed.Under the condition that the relevant codes are met,the safety of high-rise buildings can be guaranteed.Based on the comparative results of the story drift limits between the Chinese and American codes,this paper gives some suggestions for further relaxing the elastic story drift limits of the frame-supported shear wall structure in the Chineses code,and then evaluates the safety of the structure after relaxing the elastic story drift limits.The main work is as follows:(1)Combined with the idea of performance-based seismic design,the dynamic elastoplastic time-history analysis method,the elastoplastic analysis software PERFORM-3D and the evaluation method of structural seismic performance are introduced.(2)24 models of frame-supported shear wall structure are established with different site types,structural height,fortification intensity and transfer floor position according to Chinese code.The relevant parameters affecting the calculation of seismic action in the Chineses and American codes are compared and unified,and the comparative index of the story drift limits between the Chinese and American codes is determined.Calculation of ? are performed by using ETABS,analysis on effects on ? of site types,structural height,fortification intensity and transfer floor position is also conducted;Based on the comparison result,it is concluded that the elastic story drift limits of the frame-supported shear wall structure in the Chineses code is too strict,and it is reasonable to relax the elastic story drift limits,and it is suggested that the elastic story drift limits should be further relaxed.(3)Through an actual out-of-code structural engineering example,the displacement results of the two national codes are calculated under the earthquake action of different fortification intensity,and then ? is obtained.It is further demonstrated that the elastic story drift limits of the frame-supported shear wall structure system in the Chinese code is more stringent than that of the American code,which is consistene with the conclusion drawn in the third chapter of this paper and further improves the calculation results of the third chapter of this paper.(4)According to the calculation results of the third chapter in this paper,five framesupported shear wall structures are designed,and their elastic story drifts are adjusted from 1/1000 to 1/600.The elastic calculation results of each model are analyzed and the material consumption is calculated.The elastic-plastic analysis of these structures under rare earthquake are carried out by using PERFORM-3D software,and the safety of these structures are evaluated by the performance-based seismic evaluation method,which demonstrates the feasibility of Guangdong technical specification for concrete structures of tall building to relax the elastic story drift limits of the frame-supported shear wall structure,and there is still room to relax this limit.