弦支穹顶结构动力反应分析

Dynamic analysis of suspend-dome structures

以天津开发区商务中心大堂的弦支穹顶为研究对象,分析了弦支穹顶结构体系的自振特性,分别运用随机模拟风振分析方法和时间历程分析方法,对其进行了风振和地震反应分析,得到了结构在动力荷载作用下的响应时程,并对分析结果进行了频谱分析和统计分析。研究发现弦支穹顶结构的自振频率呈密集型分布,且振型复杂;结构的风振响应基本以受迫振动为主,没有出现明显的峰值共振现象;结构的地震响应在前几阶基频处出现了较为明显的峰值共振现象;从振动的幅值角度看,风荷载的动力作用效应相对于地震荷载要显著。

The roof of Commercial Center in Tianjin Development Area is a typical suspend-dome structure which firstly built in China. Based on the studies of natural frequency and vibration mode, the wind vibration and earthquake analysis are carried out by using the nonlinear finite element approach and the time history method respectively. The response curves under the dynamic loads are obtained, and the spectral analysis and statistical analysis of the calculated results are given in details. Several conclusions can be made as follows. The natural frequencies of the structure concentrate in a small range and the vibration modes are very complicated. By the probe into the response power spectrum, the wind vibration response of the structure mainly occurs in the zone of transcendental frequency of impulsive wind ,which proves that the response is forced vibration; the earthquake response mainly oc- curs in the zone of first frequencies of the structure itself ,which proves that the response is peak resonant vibration. As for the amplitude value of vibration, the dynamic effect of wind vibration is larger than earthquake response.