Investigation of Wind Structure Interactions for Low Rise Buildings

历史记录表明，极端大风造成的财产损失和生命损失几乎每年都会发生，按照目前的水平，美国每年的经济损失总额估计在400亿美元左右。风害大多发生在低层建筑中，但对低层建筑风场的系统基础研究还很少，本文通过水槽模型实验研究了极端风与低层建筑的相互作用。流动可视化技术被用来获得复杂的风-结构相互作用的基本见解，特别是典型低层建筑周围的屋顶流和基流的特征。还研究了风方向性和附近干扰结构的影响。精心控制的水流产生了类似于自然风的流动。利用光弹性技术研究了建筑围护结构上的应力模式。在建筑物模型上涂覆光弹涂层，然后在水槽中进行测试，以揭示风与建筑物相互作用过程中的应力分布及其大小。能够同时观察附近的流场和由于流体载荷而产生的建筑物上的应力分布，是理解风-结构相互作用的详细性质的重要进步。本文的研究成果对于为低层建筑抗极端风设计奠定良好的工程科学基础具有重要意义。

Historical records have shown that damage to properties and loss of lives due to extreme winds have occurred almost every year, and that at current levels, the total economic loss in the US has been estimated in the order of $40 billion per year. Most wind damages occur in low-rise buildings, yet systematic fundamental studies of wind flow over them are very few.In the proposed study, interactions between extreme winds and low-rise building are investigated experimentally on building models in a water-channel facility. Flow visualization techniques are used to gain fundamental insights into complicated wind-structure interactions, in particular, the characteristics of roof flow and base flow around typical low-rise building. The effects of wind directionality and of nearby interfering structures are also investigated. Carefully controlled water flows are produced to resemble the natural wind flow in action.Stress pattern on a building envelope is investigated using the techniques of photoelasticity. Photoelastic coating is applied on a building model, which is then tested in the water channel to reveal the distribution of stresses and their magnitudes during wind-building interaction.The ability to observe simultaneously the nearby flow field and the stress distribution on the building, resulting from fluid loading, represents a significant advance towards understanding the detailed nature of wind-structure interaction. The results of the present investigation are of fundamental importance to developing a sound engineering-science base for the design of low-rise buildings against extreme wind.