大跨度点支式幕墙支承结构风振性能分析

广州新白云机场航站楼主楼点支式玻璃幕墙结构,长108m、高33m,采用钢桁架与预应力索桁架交叉的混合支承体系。本文针对该幕墙支承体系的三种结构方案,应用非线性有限元软件,对其风激动力性能进行分析,给出了方案合理性的评价。主要工作有:应用子空间迭代法分别对单榀索桁架和整体结构进行自振特性分析,得到相应的频率和振型;应用非线性随机模拟风振分析方法分别对三种结构方案进行整体分析,得到结构在脉动风作用下的响应时程;对风振分析结果进行统计分析,得到可供设计参考的风振系数。计算结果表明:三种结构方案的风振动力性能差别较大;其中,方案一最差,在脉动风作用下发生了弯扭跳跃式失稳;方案三最好,表现出良好的动力稳定性和整体工作性能。

Study on Wind-induced Vibration of a Large-span Dot Point Glazing Supporting System

In this study, a wind induced response analysis was conducted for an actually designed large span dot point glazing supporting system, which has use the combination of cable truss and steel frame as glass supporting structure. The height of the structure at its highest point and the length of the long span are 33m and 108m respectively. Three schemes were brought up during the structural design stage to determine which was the best among their dynamic characters. The study composed of three parts. Firstly, a frequency analysis by subspace iteration method was carried out to investigate the natural frequency and vibration mode of a single cable truss and the whole structure. Secondly, a multi point fluctuating wind pressure time series was simulated by the Monte Carlo method. Then, a dynamic response analysis in time domain was carried out using the wind pressure time series by means of a nonlinear finite element approach. Finally, a ratio of maximum to mean response was proposed as wind load effect coefficient, which could be used in wind resistant design to estimate the member displacement and stress induced by fluctuating wind force. Moreover, an evaluation of the three schemes was given based on these analysis results.