水平侧向力分布模式的施加问题是合理进行pushover分析的关键环节。对于可以简化为平面模型的结构,传统的水平侧向力分布模式表现出较好的适用性,但对于因扭转不规则而导致必须采用空间模型的结构则并不适用。为此,针对扭转不规则结构的水平侧向力分布模式问题,并基于该类结构的地震响应特征,通过引入水平侧向力调整系数和水平侧向力分配系数,提出了扭转不规则结构改进的水平侧向力分布模式。对一具有典型扭转不规则特性的空间钢框架结构分别进行改进分布模式下的pushover分析和IV类场地典型地震动作用下的弹塑性时程分析,计算结果显示:改进分布模式下的pushover分析体现出扭转效应对结构反应的影响,并在一定程度上反映出更多的结构抗震信息,验证了所提出模式的可行性,说明pushover分析法也同样适用于扭转不规则结构。
The influence of lateral-load pattern on models is a key to pushover analysis.For a structure which can be simplified to a plane model,the traditional lateral-load pattern shows a practical application.But it doesn't work when it comes to those that must be simulated as a space model because of torsion-irregular.Aiming at finding an appropriate lateral-load pattern for pushover analysis of torsion-irregular structures,and based on the seismic response of torsion-irregular structures,a modified lateral-lode pattern is produced by introducing the lateral-load adjustment coefficient and the lateral-load distribution coefficient.These two coefficients can consider the issue of uneven stiffness distribution and the influence of high order modes respectively.At last,an example using both SAP2000 for pushover analysis and dynamic time-history analysis testifies the feasibility and validity of the proposed model.The result shows that the modified pushover analysis can get more structural seismic information than dynamic time-history analysis,and it proves the potentiality of the use of pushover analysis in torsion-irregular structures.