竖向不规则RC框架结构连续倒塌动力放大系数研究

Dynamic Increase Factor of Vertically Irregular RC Frame Structure in Progressive Collapse

为研究竖向不规则钢筋混凝土(reinforced concrete,RC)框架结构连续倒塌过程中的动力响应特征,以一系列不同布置形式的竖向不规则RC框架为对象,基于变换路径法,采用静力非线性和动力非线性分析方法,研究底层柱失效时建筑形式与动力放大系数之间的关系,并针对特定建筑形式提出塔群层数比和塔群跨数比。研究表明:GSA2003在静力非线性方法中所建议的动力放大系数2.0偏于保守;减小结构的塔裙层数比,降低结构不规则程度能够有效地提高剩余结构承受动力荷载的能力;在下部裙楼跨数一定的情况下,增大结构塔群跨数比能够降低结构连续倒塌的风险。

In order to research the dynamic response of vertically irregular RC frame structure in progressive collapse,a series of vertical irregular RC frames were built up as analysis models,and each model with the remove of bottom interior column was analyzed by using nonlinear static method and nonlinear dynamic method based on alternate path method,respectively. Two new analysis indexes were proposed for the vertical irregular RC frames. The result showed that the dynamic increase factor 2. 0 suggested in GSA2003 is conservative. The ability of structures subjected to dynamic loads can be strengthened by reducing the value of B∶ A or reducing the irregularity of structure,and the ability of the structure to resist progressive collapse can also be improved by increasing the number of tower bays properly.