铁路房屋坡屋面的抗风设计研究

Wind Resistance Design for Railway Buildings with Sloping Roof

铁路站房、生产和生活房屋均要求采用坡屋面，但对坡屋面的形式、坡角如何采用则无规则可循，设计者通常只注重外形的美观，很少考虑其抗风能力。文章根据已有的风洞试验数据，分别对双坡、四坡屋面在不同坡角、不同风向角的屋面抗风能力进行了分析和研究，并与现行《建筑结构荷载规范》进行了对比，提出了按规范风压系数取值可能造成局部构件设计的安全隐患；风洞试验揭示最不利的风压是出现在斜风向，而不是在规范采用的0°和90°方向上，所以在进行坡屋面风载设计时应特别关注当地的主导风向；双坡屋面最佳设计坡角是在25°～30°范围内，此时双坡屋面所受到的风荷载最小，风向角在45°～90°时，双坡屋面的最大平均风压大于四坡屋面，此时应优先考虑选用四坡屋面。

For railway station buildings, manufacturing facilities and residential buildings, sloping roof is required to be adopted, but there are no standards for the shape and slope angle of the sloping roof. The architect only concerns with the appearance of such buildings without considering their anti-wind capacities. Based on the existing wind tunnel test data, the paper analyzes and studies the anti - wind capacity of double pitched house and hip roof house, with different slope angels under different wind directions; it also compares the test results with current Chinese Loading Code for De- sign of Building Structures, the results show that it may cause local potential safety hazard for members when values in accordance with coefficient of wind pressure. Wind tunnel test shows that the most disadvantageous wind pressure ap- pears on diagonal wind direction, instead of 0° or 90° adopted in existing wind load codes, therefore, in the wind resist- ance design of buildings with sloping roof, local prevailing wind direction shall be considered specially; the optimum slope angle of double pitch buildings is between 25°and 30°, while the roof takes the minimum wind load. When the wind direction changes from 45° to 90°, the maximum mean wind pressure on double pitch roof is larger than that on hip roof, in this case, priority shall be given to hip roof.