联肢剪力墙墙肢附加轴力计算方法及其影响分析

Calculation method and impact analysis of additional axial force in wall piers for coupled shear walls

为解决目前计算墙肢附加轴力需要复杂的数值模拟或繁琐的解析求解的问题,并量化附加轴力对联肢墙承载力的影响,选取合适的坐标系,基于连续连杆法建立了以附加轴力为未知函数的微分方程,推导了三种不同形式水平荷载作用下新的墙肢附加轴力解析公式,给出附加轴力简便实用的计算方法,并与现有方法和数值模拟计算结果进行对比;利用本文方法分析了影响附加轴力大小的主要因素;采用联肢墙受弯和受剪强度指标,分析了附加轴力对联肢墙承载力的影响。研究结果表明:利用本文方法只要已知联肢墙几何尺寸和水平荷载形式,即可快速准确地得到联肢墙墙肢的附加轴力,与现有方法相比,本文方法更加简便;同一个联肢墙在不同形式水平荷载作用下,其附加轴力的大小受总倾覆力矩的影响比基底剪力更明显;附加轴力虽然会降低联肢墙受剪承载力和两片墙肢总受弯承载力,但随着附加轴力的增加,联肢墙整体受弯承载力近似呈线性增加。

The existing calculation method for the additional axial force(AAF)in wall piers of coupled walls(CWs)requires complex modeling or computing.To solve this problem and to quantify the effect of AAFs on the strength of CWs,a differential equation with respect to AAF was established using a selected coordinate based on the method of continuous connecting links.New analytical formulas of AAF for three types of lateral loads were developed.A simple and practical calculation method for AAF was proposed,which was compared with existing formulas and numerical simulations.The main factors affecting AAF were analyzed using the proposed method.The effect of AAFs on the strength of CWs was investigated using flexural and shear strength indexes.Results show that AAF could be obtained by the proposed method quickly and accurately if the CW geometry and the types of lateral loads were specified,which is simpler than the existing method.The value of AAF for a CW under different types of lateral loads was more affected by the total overturning moment(OTM)than the base shear.The effect of AAFs reduced the shear strength of CWs and the sum of flexural strength of individual wall piers,but the global flexural strength of CWs was almost linearly increased with the increment of AAFs.