地震动多点激励下大跨空间网架结构的反应分析  

SEISMIC RESPONSE ANALYSIS OF LONG-SPAN SPATIAL TRUSS STRUCTURE UNDER MULTI-SUPPORT EXCITATIONS

作　　者：白凤龙[1] 李宏男[1] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《工程力学》2010年第7期67-73,102,共8页Engineering Mechanics

基　　金：教育部创新团队基金项目(IRT0518);高等学校学科创新引智计划项目(B08014)

摘　　要：基于直接输入位移法建立了多点激励时程分析模型,采用三角级数法模拟生成满足给定的相干函数和规范反应谱的非平稳空间地震动。选取大跨度柱支承空间网架结构为研究对象,分别进行了结构在地震动一致激励、行波激励和多点激励作用下的动力反应分析,对其进行了比较研究。分析结果表明:在水平地震动多点激励作用下,与一致激励相比,上部结构控制杆件轴力和柱顶位移的幅值变化与地震动作用方向有关,地震波先到达的下部支承柱结构的内力反应增大;在竖向地震动作用下,结构在多点地震激励下的反应明显大于一致激励。网架结构在多点地震动激励下与行波激励下的反应结果变化规律相似,多数情况下行波激励得出偏于不安全的结果。因此,忽略地震动的空间变化会严重低估大跨度空间网架结构的反应。The time history analytical model under multi-support excitations is established based on the direct displacement input method. Non-stationary spatial ground motions are generated by trigonometric series method, which are compatible with the given coherence loss function and code response spectrum. The long-span spatial truss structure supported by columns is considered, and the dynamic responses of the structure under uniform excitation, wave-passage excitation and multi-support excitations are investigated comparatively. In contrast to the uniform excitation, under horizontal multi-support excitations, the internal force responses of the supporting columns which are first excited by seismic waves are amplified, the amplification of both the column-top displacements and the axial forces of control bars in the superstructure are related with the direction of seismic excitation. The seismic responses of the structure under vertical multi-support excitations are larger than those under vertical uniform excitations. The variations of the analytical results under multi-support excitations of the truss structure are close to those under the wave-passage excitation, but the response results obtained from the wave-passage excitation are unreliable in most cases. Therefore, neglecting ground motion spatial variations may lead to a substantially under-estimated seismic response of long-span spatial truss structure.

关 键 词：空间网架结构 多点激励 时程分析 相干函数 反应谱 

分 类 号：TU393.3[建筑科学—结构工程]