Seismic Response Analysis Of Steel Grid Box-like Structure Subjected To Near-fault Ground Motions

Compared with traditional structure system,steel grid box-like structure as a new type of structure system has a good promotion prospects in mechanical characteristics,architectural features,energy conservation and economy aspects.With the expansion of the scope of urban construction,more and more construction is likely to be in the near fault region,because of the effect of velocity pulse near-fault ground motion effects on structure is closely related to the cycle structure itself,velocity pulse will significantly change the dynamic response of the structure.And the study of seismic performance of steel grid box structure does not take into account the near fault earthquake action on the influence of the structure,therefore,in order to study such a new type of structural system under the effect of near-fault ground motion of the seismic performance has important practical significance.This article mainly carries on the following research work:(1)The basic characteristics of the near-fault ground motion for the comprehensive and detailed introduction,and combined with selected seismic records,this paper has carried on the response spectrum analysis on the near fault and fault type pulse non pulse and general cosco field seismic record.(2)This paper has introduced the basic principle and mechanics characteristic of the steel grid box structure system.Based on multi-layer and high-rise steel grid box-like structure as the object,the structure finite element analysis model is established,dynamic characteristics of steel grid box structure analysis has been clear about the natural vibration characteristic of the structure.(3)Established the multi-storey and high-rise steel grid box structure nonlinear analysis model of nonlinear time history analysis method,choose near fault and fault type pulse seismic record the pulse type and cosco field seismic record as a general ground motion input,seismic response analysis of steel grid box structure,from the structure displacement response,the peak acceleration,base shear,and investigated the distribution of plastic hinge structure under the effect of different seismic dynamic response.(4)Compared the result of the earthquake response analysis,we can conclude that the structure in near fault under the action of earthquake dynamic response than general cosco fieldunder the action of earthquake dynamic response.With the influence of near-fault pulse-like ground motion for structure is closely related to the structure itself cycle,for multi-layer steel grid box-like,near-fault pulse like seismic dynamic response of the structure is less than near-fault non pulse-like dynamic response.For high-rise steel grid box-like structure,the action of near-fault pulse-like earthquake dynamic response value was significantly greater than near-fault non pulse-like dynamic response.(5)Because near fault type pulse seismic action will increase the high-level structure displacement and base shear demand significantly,especially change the displacement between layers along the layer of the high-level structure of distribution,therefore,in this type of high-rise steel grid box structure's design,considering the effect of velocity pulse,it is necessary to fully consider the existence of the adverse factors.