Analysis Of Multi-support Seismic Response For The Long Span Spatial Lattice Structure

The seismic input is the precondition and base for structural response analysis. It isassumed in the conventional coherent-vibration input that all of the support points havethe same ground movements, while carrying on the analysis of the long span spatiallattice structure to response of earthquake. This is equal to treat foundation as rigid body.If the structural size is far smaller than the wavelength of earthquake, this kind ofhypothesis can be accepted. Actually, because the difference of the seismic character andgeology and seismic transmission, the ingoing seismic wave is variable on the time andspace, even other conditions are completely consistent, the time which each support pointof aqueduct receive seismic wave is fall behind each other, because the distance ofsupport points to the focus of earthquake is different, in same time, the movement whichreceived by each support point is different, this is the question of multi-support seismicinput. Using ANSYS soft ware and basing on the model of the long span spatial latticestructure, this text builds two double-layer reticulated shell model, whose span are 120meters. Based on the modal analysis of the structure and ANSYS Parameter DesignLanguage,the programs of coherent-vibration input and multi-support seismic input aredeveloped. Using these programs, this paper calculates the dynamic response of model.This paper chooses 14 nodes and 14 cells to compare the differences betweencoherent-vibration input and multi-support seismic input. Analysis results in theconclusion: the result of multi-support input is larger than coherent-vibration input. Invertical wave, vertical displacement, vertical acceleration and internal force ofmulti-support input are larger than coherent-vibration input.