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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。
Based on the direct input displacement method, a multi-point excitation time history model is established. The triangular series method is used to simulate the non-stationary spatial ground motion that satisfies the given coherence function and normalized response spectrum. Taking the large-span column-supported space truss structure as the research object, the dynamic response analysis of the structure under the action of uniform excitation, traveling wave excitation and multi-point excitation is carried out respectively. The results show that compared with the uniform excitation, the amplitude of the axial force and displacement at the top of the control rod of the superstructure is related to the direction of earthquakes, and the lower support column structure The response of the structure under multi-point seismic excitation is obviously greater than that of the consistent excitation. Under multi-site ground motions, the grid structure behaves similar to that under traveling wave excitation. In most cases, the traveling wave excitation results in a partial unsafe result. Therefore, ignoring the spatial variation of ground motions can seriously underestimate the response of large-span space grid structures.