大跨度内凹弧形镂空屋盖结构风洞试验及风振分析研究

WIND TUNNEL TEST AND WIND VIBRATION ANALYSIS OF LARGE-SPAN CONCAVE CURVED HOLLOW ROOF STRUCTURE

为明确风荷载取值,对大跨度内凹弧形镂空屋盖进行了刚性模型风洞试验,探究了全风向角作用下屋盖风压系数最值的分布规律,分析了典型测点风压系数随风向角变化的特征规律,建立了屋盖的分块体型系数。试验结果表明,大跨度内凹弧形镂空屋盖在全风向角作用下,风压系数最值在迎风边缘区域远高于中部区域,且主要承受负风压。设计时中部下凹镂空悬索区域应同时考虑风压和风吸作用,两侧延伸桁架区域可仅考虑风吸作用。基于风洞试验得到的风荷载时程,对屋盖结构进行了风振动力分析,结果表明,屋盖风振位移响应以竖直z向为主,上吸和下压风荷载合力分别在120°和240°风向角作用下最大。屋盖的等效静力风荷载在迎风边缘及角部最大,抗风设计时应引起足够重视。

In order to determine the value of wind load,the wind tunnel test was carried out with a rigid model to the large-span concave curved hollow roof,the distribution rule of the maximum wind pressure coefficient of the roof in the whole wind direction was explored,the characteristics of the wind pressure coefficient of typical measuring points corresponding to changes in the wind direction were analyzed,and the block shape coefficient of the roof was determined.Test results show that,for the large-span concave curved hollow roof in the whole wind direction,the maximum wind pressure coefficient in the windward edge area is much greater than that in the middle area,and the roof is mainly subject to negative wind pressure in this case.In the design,the wind pressure and wind suction are considered in the central concave hollow suspension cable area,while only the wind suction is considered in the extended truss areas on both sides.The wind vibration dynamic analysis of the roof structure was performed based on the wind load time history obtained through the wind tunnel test.Results show that the wind vibration displacement response of the roof is mainly in the vertical z direction,and the resultant force of wind suction and pressure loads reaches the maximum value at the wind angle of 120°and 240°.respectively.The equivalent static wind load of the roof is the largest at the windward edge and corner,which should be emphasized in the wind resistance design.