近断层大脉冲地震动对网架结构动力反应影响的研究及其简化计算模型

Study on effects of the near fault large pulse-type ground motion on the seismic dynamic performance of space truss and its simplified model

针对工程中常见的大跨空间网架结构在近断层大脉冲地震中的反应特点进行了较为深入的研究,得到了如下有益的结果:(1)为了便于工程设计中的应用,通过理论推导和数值模拟的方法,提出了一种考虑弯-剪效应的简化弹簧-质量-阻尼等效体系,该体系用以替代下部支撑结构,并和上部网架一起参与动力耦合反应;(2)简单阐述了近断层大脉冲地震动的特点,对同一个结构输入相同加速度幅值(0.1g)的脉冲地震动与非脉冲地震动两种地震波,分析比较了结构反应的差别,讨论了大脉冲速度谱与结构固有周期对结构反应影响的相关性;(3)对比分析了实际模型与简化模型在不同地震动作用下的结构反应,其结果验证了简化模型的合理性与准确性。该研究成果对从事本领域的科技人员了解大脉冲地震动对结构的影响有很好的示范效应。同时为设计人员简化计算提供了科学、简便的计算模型。

This article focuses on the research of seismic response character of common space truss under the impact of the pulse-type ground motion,and some meaningful results listed below have been obtained:( 1) In order to apply the method in the construction designing,a simplified spring-mass-damping system is put forward through the theoretical derivation and numerical simulation,which could consider the effects of bending and shearing. This system can replace the supporting structures and participate in the coupling reaction with space truss.( 2) The character of near fault large pulse-type ground motion is simply explained. The differences of the seismic response are compared between the pulsetype ground motions and the non-pulse-type ground motion of the peak( 0. 10g) acting on the same space truss. The correlation of the big pulse velocity spectrum and structure natural period of structure response is discussed.( 3) The responses of the simplified model and the actual model under the impact of the ground motions are analyzed and compared. The result shows the reasonableness and accuracy of the simplified model. The research could provide a scientific and simplified model for the designers.