The Research On Seismic Responses Of Cylindrical Reticulated Mega-structure Under Multiple Support Excitations

With the development of spatial structure toward the direction of light weight, long span even super-long span,the force performances of spatial structure become more and more complicated,the traditional method of simple support excitations is not reasonable under earthquake inputting,and the the influence of multiple support excitations is needed to consider.therefore,the seismic response characteristics of long-span spacial structures under multiple support excitations become a hotspot of current researches.As a new style of spacial structure,the cylindrical reticulated mega-structure has some advantages of saving steel,big whole stiffness,adaption to super-long span,it will be used in engineering in the future.The application and development of the multi-support excitations in long-span spacial structures were reviewed and discussed in this paper,then the realization methods of multi-support excitations were put forward according to the dynamic motion equations.The seismic responses of cylindrical reticulated mega-structure, automatically generated in prepared Visual C++program,were analyzed under multi-support excitations by using time-history method in software ANSYS, and some meaningful regularities and conclusions are gained.Firstly the seismic responses were discussed under common earthquake on the condition of the main structure bearing the load by itself and cooperatively with substructures separately,and the seismic response characteristics were investigated under different traveling waves,including key nodes displacement peaks,nodes displacement time-history curves and key members inner force peaks and distribution of different position,then compared with that under simple support excitations,so as to highlight the importance of multiple support excitations of long span structures.Then the elastic-plastic properties of the the structure were studied, the structure displacement,inner force,quantity and distribution of yield members and the distribution of stress were tracked in the whole elastoplastic process on the condition of the main structure bearing the load by itself.Influence of the the structure under multi-support excitations of severe earthquake was obtained.Finally,based on the controlling indexes of displacement peaks and inner force peaks,systematic parameter analysis of the structure is carried out under simple support excitations and multiple support excitations,involved span ratio,hight factor,surface load,section area of members and span, the response influence of different parameters under different excitations were obtained.The research in this paper can provide theoretical basis and reference for the practical engineering application of such structure.