大跨度平屋面的风振响应及风振系数

WIND-INDUCED DYNAMIC RESPONSE AND WIND LOAD FACTOR FOR LONG-SPAN FLAT ROOF STRUCTURES

本文在有限元分析的基础上建立了大跨度平屋面结构在风荷载作用下的风振响应谱分析方法,并采用Davenport谱和由风洞试验得到的屋盖表面的平均风压分布系数计算了屋面的风振响应及风振系数。文中还深入探讨了屋面刚度、来流风速及风向等参数对大跨度平屋面竖向风振响应及风振系数的影响。计算表明:① 大跨度平屋面的竖向风振响应主要是由第一振型所支配,高阶振型对屋面板竖向风振响应的影响很小;② 屋面刚度及来流风速对大跨度平屋面的竖向风振响应影响比较大,但对位移风振系数的影响不太明显;③ 在工程设计中,建议采用位移风振系数来计算大跨度平屋面的等效静力风荷载。

The spectral analysis method for a long-span flat roof structure subjected to wind excitation is established by using finite element method. The wind-induced dynamic response and wind load factor of the long-span flat roofs are evaluated by using the Davenport wind spectrum and the local mean wind pressure coefficients determined in wind tunnel. The influences of roof stiffness, wind speed and wind direction on wind-induced dynamic response and wind load factor are discussed. The following conclusions are drawn: The roof response due to turbulent wind forces is dominated by the first mode and the higher mode effects are very small. The influences of roof stiffness and wind velocity on wind-induced dynamic response are considerably large, while the influences of wind load factor are slight. In engineering design, it is suggested to use wind load factor, which is defined as the ratio of wind-induced total displacement to static displacement, to calculate the equivalent static wind load of long-span flat roof structures.