低层坡屋面房屋风荷载特性风洞试验研究

对低层双坡屋面和四坡屋面建筑进行了风洞试验研究，考虑了屋面形式、屋面坡度、来流方向和挑檐长度等不同因素对屋面风压分布的影响，分析了屋面平均和脉动风压系数的分布特性。结果表明，0°风向角（来流垂直吹向屋脊）、屋面坡度为30°时，迎风屋面屋檐及屋脊附近形成较高负压，迎风屋面风压系数呈环状分布；屋面坡度为15°时，迎风屋面风压系数呈阶梯状分布。屋面体型系数受风向角、屋面坡度和屋面形式的影响较大：0°风向角、双坡屋面模型中，15°屋面坡度迎风屋面体型系数为30°屋面坡度的2.76倍；四坡屋面模型中，15°屋面坡度迎风屋面体型系数为30°屋面坡度的228倍；背风屋面体型系数受屋面坡度的影响较小；0°和45°风向角下，对于15°和30°屋面坡度，当屋面坡度相同，屋面形式由双坡改为四坡时，迎风屋面的体型系数绝对值有所增大，屋面更容易受力破坏，但对背风屋面的影响较小。

Wind tunnel test on wind load characteristic of low-rise sloping roof buildings

Wind tunnel test on wind load characteristics of low-rise gable and hip roof buildings were presented.The mean wind pressure and fluctuating wind pressure coefficient of roof with different parameters,which include roof shape,wind attack angel,roof pitch and length of roof overhang,were analyzed.The results show that high suction is formed on eave and ridge of windward roof.The pressure coefficient on windward roof shows ring-form distribution feature when the roof pitch is 30° in 0° wind direction,which is vertical to the roof ridge,and stepped distribution feature when the roof pitch is 15°.Wind direction,roof pitch and roof shape show more influence on the shape coefficient of building.The shape coefficient of windward roof on gable roof model with 15° roof pitch in 0° wind direction is 2.76 times more than that of 30° roof pitch.The shape coefficient of windward roof on hip roof with 15° roof pitch in 0° wind direction is 2.28 times more than that of 30° roof pitch.The roof pitch doesn’t affect the shape coefficient of leeward roof.When the gable roof is changed into hip roof with the same roof pitch as 15° or 30° in 0° and 45° wind directions,the absolute value of shape coefficient of windward roof is increased greatly and the windward roof becomes easier to be destroyed.However,there is little influence on leeward roof.