转动变形机制下砌体墙的等效抗侧刚度计算模型

Calculation Model of Equivalent Lateral Stiffness of Masonry Wall Under Rotational Deformation Mechanism

为了研究转动变形机制下砌体墙的等效抗侧刚度,分析了转动变形机制下砌体墙骨架曲线特点,定义了砌体墙等效高宽比参数,基于串联刚度与矩形立面刚度相等原则,推导了非矩形立面转动主体等效高宽比的计算公式;基于转动墙体在弹塑性阶段的刚度衰减规律,通过对试验数据进行拟合,得到了刚度衰减系数α和转动主体高宽比影响系数β,最终建立了转动变形机制下砌体墙等效抗侧刚度计算模型,并利用文献数据进行了验证。结果表明:转动变形机制算法中,高宽比越大的墙肢,其等效抗侧刚度下降越多,分担的地震作用越小;转动变形机制算法中,砌体墙分配的地震作用大小与方向有关,不同地震方向下同一片墙肢地震作用所占百分比不同;采用转动变形机制下砌体墙等效抗侧刚度对砌体结构进行抗震验算复核,有助于发现既有抗震设计下砌体结构的薄弱环节。

In order to study the equivalent lateral stiffness of masonry wall under rotational deformation mechanism,the characteristics of masonry wall skeleton curve under rotational deformation mechanism were analyzed and the equivalent height to width ratio parameter of masonry wall was defined.Based on the principle that the series connection stiffness is equal to the stiffness of the rectangular facade,the calculation formula of the equivalent height to width ratio of the rotating main body of the non-rectangular facade was deduced.Based on the stiffness attenuation law of rotational wall in elastic-plastic stage,the stiffness attenuation coefficientαand the influence coefficient of the height to width ratio of the rotating main bodyβwere obtained by fitting the experimental data.Finally,the equivalent lateral stiffness calculation model of masonry wall under rotational deformation mechanism was established and verified by literature data.The results show that in the algorithm of rotational deformation mechanism,the greater the height to width ratio of the wall limb,the lower the equivalent lateral stiffness and the smaller the seismic action.In the algorithm of rotational deformation mechanism,the magnitude of earthquake action distributed by masonry wall is related to the direction,and the percentage of earthquake action of the same wall limb is different in different earthquake direction.Using the equivalent lateral stiffness of masonry wall under rotational deformation mechanism to check the seismic resistance of masonry structure is helpful to find the weak link of masonry structure under the existing seismic design.