大跨度空间管桁架结构地震响应分析

SEISMIC RESPONSE ANALYSIS OF A LONG-SPAN SPACE PIPE TRUSS STRUCTURE

以某大跨度空间管桁架结构展览中心登录厅为研究对象,采用时程分析法对其大跨空间屋盖结构进行了地震响应分析,研究了其前12阶自振周期和频率,分析了单向、双向和三向地震多用下典型测点的位移和内力响应。研究表明:前12阶振型中不存在平扭耦合,结构的质量和刚度分布较为均匀;在单向和多向地震作用下,各点在x向的最大位移比近似为1.0,y向和z向的地震作用对结构x向位移的影响很小,三向地震作用下结构各方向位移均大于单向与双向地震作用下的位移,三向地震作用对z向位移的影响较为显著;各测点在单向、双向、三向地震作用下的轴力时程响应曲线较为相似,仅是峰值大小不同;三向地震作用下的轴力整体上明显高于单向与双向地震作用下的轴力;对于大跨空间结构,z向地震作用对其轴力和位移影响较大,采用三维地震作用输入十分必要。

Taking the landing hall of one exhibition center as the research object, the seismic response of its long span spatial roof structure was analyzed by time-history analysis method. The first 12 natural vibration periods and frequencies were studied. The displacement and internal force responses of typical measure points in unidirectional, bidirectional and three-directional earthquakes were analyzed.The results show that there is no plate-torsional coupling in the first 12 modes, and the mass and stiffness of the structure are evenly distributed. Under unidirectional and multi-directional seismic action,the maximum displacement ratio of each point in the x direction is approximately 1.0. The seismic action in the y and z directions has little influence on the x-direction displacement of the structure.The displacement of the structure in all directions under the action of three-directional earthquake is greater than that under the action of unidirectional and bidirectional earthquakes. The axial load timehistory response curves of each measure point under the action of unidirectional, bidirectional and threedirectional earthquakes are similar except that the peak values are different. The axial force under the action of three-directional earthquake is obviously higher than that under the action of unidirectional and bidirectional earthquakes. For long span spatial structures, the z-direction seismic action has a great influence on their axial force and displacement, so it is necessary to adopt the input of three-directional seismic action.