Vertical Seismic Response Analysis Of Grid Structure

Due to itself-possessed lightly, large span and so on, the grid structure has been applied inbuilding structure’s roof more and more extensive, including sport building, public building,single story industrial building,hanger. In recent years, with increasing special dimension andstructure form more and more complicated, its are bound to bring a detrimental effect for gridstructure’s seismic behavior.In this paper, the finite element software SAP2000is adopted to model two dimensionalnormal intersection and putting net truss structure、square pyramid space grids structures、diagonal square pyramid grids、square pyramid space grid of checkerboard and24×24m、30×30m、36×36m、42×42m、48×48m、54×54m6kinds of different span of24spacetruss.Modal analysis for it, summed up the change rule of natural vibration period for gridstructure, along with the change of span, natural vibration period change is very small, illustratethe change of the spatial span less influence on vertical dynamic characteristics of space trussstructure.Response analysis of vertical seismic action and coupling seismic action for30×30m、42×42m、54×54m square pyramid space grids structures model using the time history analysismethod, it is concluded that internal force and displacement of space truss structure under thevertical earthquake action samaller than internal force and displacement of space truss structureunder the coupling earthquake,with the increase of the span, the percentage difference graduallydecreases.Response analysis of vertical seismic action for24×24m、30×30m、36×36m、42×42m、48×48m、54×54m six kinds of square pyramid space grids structures using the mode-superposition response spectrum method and the time history analysis method. Dynamic internalforce coefficient was introduced, by the contrast analysis, the distribution law of grid structure’sdynamic internal force coefficient for same span; law of grid structure’s dynamic internal forcecoefficient changes for different span. To calculate the equivalent seismic coeffieien of6kinds ofdifferent span of space truss,it is a ratio that supports dynamic reaction force form the mode-superposition response spectrum method and supports static reaction force form representative value of gravity load.In SAP2000,different processing mode for bolt-sphere dead weight have aneffect on the result of internal force.The above results have a certain reference value for study on the dynamic internal force ofvertical earthquake and equivalent seismic coeffieien of grid structure, we proposed a calculationmethod to calculation of vertical seismic action,and also have important implications for thedesign specifications of grid structure design.