高跨为双坡屋面的高低屋面低跨平屋面积雪分布研究

Research of snow distribution on lower roof of step roofs with gable-roof on high part

高低屋面对雪荷载较为敏感,通过模型试验对高跨为双坡屋面形式的高低屋面低跨平屋面积雪分布形式进行研究。模型试验在哈尔滨工业大学自主研发的户外风雪联合系统中进行,该设备可在试验段内模拟自然降雪过程。根据高跨坡屋面坡度不同共设置4个模型,并针对每个模型进行了不同风速、不同风向下的试验研究。通过高跨为平屋面形式的高低屋面积雪分布的实测与试验结果的对比,验证了试验结果的可靠性。结果表明:风速越大,积雪分布不均匀现象愈加显著,但屋面积雪分布系数并未随风速增加而增大;高跨双坡屋面坡度对变跨处积雪分布影响显著,高跨为60°双坡屋面,迎风向3 m/s风速时变跨处积雪分布系数最大值达到7. 9,超出欧洲EU规范取值。

Step roofs are sensitive to snow loads,therefore,snow distribution on lower roof of step roofs with gable-roof on the high part was studied through model experiment. The model experiments were conducted in open air snow-wind combined laboratory developed by the Harbin Institute of Technology,which could simulate the process of natural snowfall. The experiments consisted of four models according to different slopes of the upper gable-roof,and were conducted in different wind velocities and directions. The reliability of the experiment results was verified through comparison of field measurements and experiments on step flat roofs. The results show that the higher the wind velocity,the more significant the unevenness of snow distribution,but the roof snow distribution coefficient does not increase with the wind velocity. The slope of the upper gable-roof has significant influence on snow distribution. For the model which has 60° gable roofs and is under a wind of 3 m/s from the windward side,the maximum snow distribution coefficient is 7. 9 which is beyond the value in Eurocode.