多点激励下地震动输入模式探讨及有限元软件实现方法研究

进行大跨度结构的地震响应分析时,需要考虑地震动多点非一致激励的影响。基于动力学平衡方程,进一步推导多点激励地震响应分析的位移输入模型和加速度输入模型。进一步提出3种能适用于现有通用有限元软件的多点地震动输入模型的实现方法——大质量法、大刚度法及直接位移法,并细致阐明各种方法的计算原理。最后,以某主跨为850m的悬索桥为工程背景,基于SAP2000软件平台,分别采用不同方法进行多点激励地震响应分析,并简单分析大跨悬索桥在多点地震响应下的响应规律。

Discussion of Seismic Input Model under Multi-support Excitation and Study of Finite Element Software Realization Method

For analyzing the seismic response of long-span structure,it is required to consider the influence of multi-support non-uniform excitation.Based on the dynamic equilibrium equation,it is further to derive the seismic response analysis of displacement input model and the acceleration input model under the multi-support excitation.The article puts forward three practical methods – large mass method,large stiffness method and direct displacement method of suitable for the multi-support seismic input model by the currently common finite element software,sets forth the calculation principles of various methods in detail,and analyzes the multi-support excitation seismic response by the different methods based on SAP2000 software platform and according to the engineering background of a suspension bridge with the main 850-m span,and finally briefly analyzes the response law of long-span suspension bridge under the multi-support seismic response.