Wind loading on buildings caused by straight line boundary layer winds has been thoroughly investigated in the past. The effects of vortex loading on structural projections will induce crosswind loads and torsional loads on low rise building which has severe dynamic resonant effect not only on the structural projections but also on over all structural elements of a building. These structural projections can be in the form of cantilever balconies, canopies, sunshades, overhangs, aesthetically projected elements. The purpose of each of these projections is different and designed to suit the convenience of habitats. During the tornado, the damage of projections becomes flying debris due to the fatigue effect of fluctuating pressure. In the present study,a model of low-rise buildings is tested under the influence of tornado-induced vortexes. Models were tested for F3 – F4 tornado for the wind speed 60m/s to 90m/s. Tornadoes of vortex core diameter 0.46 m to 1.06 m in a smooth open terrain, simulations were carried out.A prototype of model of building in a scale of 1:400, actual dimensions of building is 20m x 20m x 10 m; the prototype model is prepared using flexi glass. An arrangement is made to study the effect of building on the ground terrain in surrounding region of building. Model was provided with pressure tapping to measure the surface pressure on all the walls and roof.

中文翻译：

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龙卷风涡致气动载荷作用下低层建筑及周边地形风压评价

过去已经彻底研究了由直线边界层风引起的建筑物风荷载。涡流载荷对结构投影的影响将在低层建筑上引起侧风载荷和扭转载荷，这不仅对结构投影而且对建筑物的所有结构元件都有严重的动态共振影响。这些结构投影可以是悬臂式阳台、檐篷、遮阳篷、悬垂、美学投影元素的形式。这些预测中的每一个的目的都是不同的，旨在适应栖息地的便利性。在龙卷风期间，由于脉动压力的疲劳效应，突起的损坏变成了飞溅的碎片。在本研究中，对受龙卷风引起的涡流影响的低层建筑模型进行了测试。模型在风速 60m/s 到 90m/s 的 F3 – F4 龙卷风中进行了测试。涡芯直径0.46m至1.06m的龙卷风在平坦开阔的地形上进行模拟。 1：400比例的建筑模型原型，建筑实际尺寸为20m x 20m x 10m；原型模型是使用柔性玻璃制备的。研究了建筑物对建筑物周边地区地面地形的影响。模型配有测压装置，用于测量所有墙壁和屋顶的表面压力。原型模型是使用柔性玻璃制备的。研究了建筑物对建筑物周边地区地面地形的影响。模型配有测压装置，用于测量所有墙壁和屋顶的表面压力。原型模型是使用柔性玻璃制备的。研究了建筑物对建筑物周边地区地面地形的影响。模型配有测压装置，用于测量所有墙壁和屋顶的表面压力。