结构地震响应分析的波动方法

WAVE PROPAGATION METHOD FOR SEISMIC RESPONSE ANALYSES OF STRUCTURES

在结构中构造被研究块体,针对其质心建立动力平衡方程;由考虑弯剪变形的杆端力与杆端位移之间关系式推导出段间内力计算公式;在时间域上交替运用动力平衡方程和段间内力计算公式进行递推计算,给出高耸结构、三维框架结构地震响应分析的波动方法。对于高耸结构,考虑了被研究块体质心与空间离散结点之间的偏心问题,给出了修正的动力学方程。利用框架结构地震响应分析的波动方法研究了短跨结构的行波效应问题。结果表明:采用传统方法计算给出的电视塔地震响应结果会偏小。考虑行波效应时,二维和三维框架结构柱子的剪力和梁端弯矩存在显著增大现象。

The investigated lumps are formed in the structures and then the dynamic equilibrium equations of the investigated lumps are established about their centroids. The calculating formulae of the median axial force, shear force and bending moment of the element have been derived. The wave propagation methods, used to analyze the earthquake responses of high-rise structures and three-dimensional frame structures respectively, are then implemented by using these dynamic equilibrium equations and the calculating formulae of interior forces on the median cross-section recursively in a time domain. The eccentricities between the discrete nodes and the corresponding centroids of the investigated lump are considered and then the corrected dynamic equation is presented for high-rise structures based on the multi-degree-of-freedom model. The wave passage effects have been studied using the wave propagation method for earthquake response analyses of frame structures. Numerical results show that the computational results given by the conventional method may be smaller than their actual earthquake response for the high-rise structures. The seismic wave passage effects can cause the column shear forces and beam-end bending moments to increase remarkably.