基于变换路径法的竖向不规则RC框架动力增大系数研究

Study on Dynamic Increase Factors of Vertically Irregular RC Frame Using Alternate Path Method

以一系列不同布置形式的竖向不规则RC框架为对象,基于变换路径法对底层中柱失效的框架分别进行了非线性静力和非线性动力倒塌分析,研究了动力增大系数的取值范围,提出了针对该特定结构形式的分类指标。结果表明:GSA 2003中建议的动力增大系数2.0偏于安全,使所设计结构具有较高安全储备的同时,也难免造成一定浪费;随着塔裙层数比的增大,结构抵抗荷载动力效应的能力逐渐降低,在偶然荷载作用下发生倒塌的风险也随之增大;减小结构塔裙层数比,降低结构不规则程度能够减小结构倒塌风险。

Taking a set of vertically irregular reinforced concrete （RC） frame as the analysis models, nonlinear static analysis and nonlinear dynamic collapse analysis were carried out basedon the alternate path method for framework with the bottom interior column failure. The value range of dynamic increase factor was studied. Meanwhile, a new classification index waspresented. The results show that the suggestive dynamic increase factor 2. 0 of GSA 2003 is conservative, and it is inevitable to cause a certain waste in design while the design of structurehas a high safety reserves. As the ratio of tower layer increases, the ability of structure to resist dynamic load decreases and the structural collapse risk increases under the action of accidentalload. The collapse risk of structure can be reduced by decreasing ratio of tower layer and the irregularity of structure.