用集中质量迁移法求多层框架的基本自振周期

Determination of Fundamental Natural Period of Multistory Frame by Using Moveable Method of Concentrated Mass

本文通过把多层框架简化为质量集中于楼层位置的多自由度体系,再将楼层处的质量迁移到框架的顶层使其转化为单自由度体系,从而推导出多层框架基本自振周期的计算公式。公式中抗侧移刚度采用“D”值,因而多层框架基本自振周期的计算相当简便。将按本文方法计算的结果与按矩阵迭代法、能量法以及国家《建筑结构设计抗震规范》中建议的统计公式计算的结果进行了对比,证明采用本文方法计算的结果比较可靠。

The formula for determination of fundamental natural period of multistory frame have been derived in this paper by simplifying multistory frame as a multiple-degree-of-freedom systems with concentrated mass on the story and then transforming it into a single-degree-of-f reedom system, moving the concentrated mass onto the apex of the frame. The value D can be taken as the lateral stiffness in this formula so that the calculation is very simple and convenient. The results obtained by the given method are compared with those obtained by matrix iteration method,energy method,and statistical formula specified by 《National Aseismatic Design Code for Industrial and Civil Buildings》,showing satisfactory agreement.