Research On IDR Limit Value Of High-rise Composite Structural Systems With Separated Gravity And Lateral Resisting Systems

In order to improve the design standardization degree and the assembly construction efficiency,a new composite structural system with separated gravity and lateral load resisting systems is proposed in this dissertation.The elastoplastic behavior under earthquake of this structural system is investigated numerically,considering different limit values of inter-story drift ratio(IDR)as design control criterion.The seismic performance of the structural system is also evaluated by varied indicators,and the reasonable IDR limit value is finally proposed.The main research works and results are as follows:(1)The numerical simulation and the fragility analysis of the main structural components in the composite structural system are completed.The efficient numerical models of the composite frames,the RC shear walls,the RC coupling beams and the braces in the composite structural system are established based on the general-purpose finite element(FE)program MSC.Marc.The fragility curves of those components are developed through parametric analysis and literature review of past research and database documents.(2)The seismic mechanism of the composite structural system is revealed.With IDR limit value as the design control criterion,the structural schemes under different design control levels are determined,of which the FE models are established.By means of FE anlysis,the seismic mechanism of the composite structural system under lateral loads,including the lateral displacement pattern,the plasiticy development mechanism and the failure mode,are compared with the traditional structural system.(3)The seismic behavior of the composite structural system under maximum considered earthquake is investigated.The static push-over analysis is carried out on the structural cases,and the displacement response results of the composite structural system are obtained.The damage of the structural components is evaluated by fragility analysis,and the seismic performance of the composite structural system is compared with the traditional structural system based on the safety factor.(4)The dynamic responses of the composite structural system under different earthquake excitations are analyzed.The elastoplastic dynamic time-history analysis is carried out on the structural cases,and a possible range of displacement results is obtained using Monte Carlo analysis to explore the uncertainty of the input earthquake excitations.The seismic performances of different structural cases are evaluated by the probability of incurring structural collapse.(5)The seismic fragility of the composite structural system is developed.The dynamic process of the structural cases is investigated by incremental dynamic analysis(IDA).The critical damage states of the composite structural system are determined referring to the seismic performance levels of the traditional structural system.The seismic fragility curves of the composite structural system are determined,and the probabilities of incurring different damage states,as well as the seismic damage risk,are evaluated.On the basis of research above,for the high-rise composite structural systems with separated gravity and lateral resisting systems under frequently occurred earthquake,the reasonable range of the IDR limit value in design is 1/800～1/1000,and the limit value of1/1000 is recommended conservatively.