砌体房屋无洞独立墙段层间侧移刚度的转角影响研究

Research of Influences of End Rotation Angle on Equivalent Lateral Stiffness of Wall Segment of Masonry Structure

按照抗震规范,刚性楼盖砌体房屋的层间墙段水平地震剪力可按其等效侧移刚度比例分配。然而在计算侧移刚度时,往往假定上下端部截面无转动,从而使计算结果可能产生较大的误差甚至错误。为此,本文基于理论分析,考虑端部截面的转角影响,推导了无洞层间墙段的等效侧移刚度表达式,提出了转角影响系数α;进一步针对受均布及倒三角形水平作用,得出了α的具体计算公式及相关参数;在此基础上,计算给出了不同层数砌体结构的层间墙段α值实用图表。最后进行了实例计算比较。研究表明,本文方法的结果较规范法精度较高,满足抗震设计精度要求,可适用于简化分析。

According to seismic design code, storey earthquake shear may be allotted to wall segments in the proportion of their equivalent lateral stiffness in masonry structures with rigid floors. However, when calculating of equivalent lateral stiffness it is usually assumed that there is no relative rotation between bottom and top section of storey walls, which often produces significant error or mistakes. In this paper, formulas of equivalent lateral stiffness of storey walls segment are derived from theoretical analyses of influences of rotation angle in the end, and influence factor a of rotation angle is put forward. Furthermore, the idiographic formula of a is derived from the assumption of separate walls subject to horizontal force in the form of equal or reverse triangle load along height. Based on above researches, some practical charts are given to calculate a of wall segment. Finally a practical example is calculated, and results of different methods are compared. Researches show that the method put forward in this paper is more exact than the traditional method in seismic design code, and the precision of the method can satisfy the requirements of the seismic design much more, so it is fit for simplified analyses.