Full Scale Measurment Study for Wind Forces on Rooftiles

掌握屋面瓦的风力特性对于包括屋面瓦在内的建筑物的防风性能设计和防止屋面瓦飞扬碎屑造成的二次破坏具有重要意义。然而，由于存在相似律等问题，利用风洞试验采用缩尺模型来测量屋面瓦片上的风力并不容易。因此，不能说屋面瓦防风设计的数据到目前为止已经完全准备好了。然后，为了丰富防风设计的数据，本研究利用实际尺寸的瓦片和一栋建筑，在自然风作用下对屋面瓦片两侧的风压进行了测量。两种典型类型的瓷砖，称为J型和F型，进行了测试。测量结果考虑了风压和风力与瓦位和风角的关系。结果，以下事情变得清晰起来。1)J型和F型各风速系数对风向的质变规律相似。2)当风与屋顶成一定角度时，强大的升降机作用于瓷砖。3)作用在瓷砖上的风力中，脉动风力占主导地位。4)作用在瓦片上的外压和内压的风压变量在低频区具有较高的相关性，但在高频区相关性降低。此外，还进行了瓷砖的静载试验，研究了荷载与瓷砖顶端位移的关系。结合前人的测风结果，推定了屋面瓦片扬起的临界风速。

It is important to grasp wind force characteristics acting on roof tiles because of the windproof performance design of buildings including roof tiles and the prevention of secondary damages caused by flying debris of roof tiles. However, it is not easy to measure the wind force acting on roof tiles by the wind tunnel experiment using scale model, because there are problems which must be solved such as the law of similarity. therefore, it cannot be said that the data for the windproof design of the roof tile are fully ready till present. Then, in this research, in order to enrich the data for the windproof design, wind pressures acting on each side of roof tiles were measured in the natural wind using actual-size tiles and a building. Two typical types of tiles, called J type and F type, were subjected. The result of the measurement was considered about the wind pressure and the wind force related with tile positions and wind angles. Consequently, the following things became clear. 1) The qualitative change of each wind force coefficient to the wind direction of J type and F type is similar. 2) A powerful lift acts on tiles when the wind directs at an angle to a roof. 3) The fluctuating wind force is dominant in the wind force acting on tiles. 4) Although the wind pressure variable of the external pressure and inner pressure acting on a tile has high correlation in a low frequency area, correlation decreases in a high frequency area. Moreover, static loading experiments of tiles were carried out to investigate the relation between the load and the displacement at the tip of a tile. Combining with the previous wind force measurement results, critical wind speed which makes roof tiles lifted was presumed.