台风致碎片运动及其对围护结构冲击破坏分析

TYPHOON-INDUCED DEBRIS MOVEMENT AND IMPACT DAMAGE ANALYSIS OF STRUCTURAL ENVELOPES

从国内外历次风灾调查统计数据可以看出,风致碎片是城市建筑围护结构遭受破坏的主要原因之一。风致碎片致使围护构件破坏的问题可以归结为3个部分:风致碎片危险性分析、碎片运动轨迹问题和围护构件抗冲击承载力分析。该文根据建筑周围环境及密集程度对碎片源环境进行了分类,建立了计算碎片分布的方法。根据碎片空气动力特性不同,对两大类碎片进行了分析。数值求解了板状碎片在空中飞行轨迹方程,并与文献实验值和数值解进行了比较,结果比较吻合。考虑风攻角产生竖向风荷载的影响,在文献方法基础上对球状碎片运动轨迹方程进行了改进,得到更为符合实际台风情况的结果。分析了围护构件抗冲击承载力,细致阐述了风致碎片导致围护构件损伤分析方法的步骤。最后利用台风珍珠实测风速、风向角和风攻角时程数据作为输入荷载,实现了某工业建筑玻璃外窗的风致碎片损伤估计,得到较好的结果。该文方法可应用于建筑风灾中风致碎片危险性评估。

The windborne debris is one of the most important causes of the envelop destruction according to the post-damage investigations. The problem of windborne debris damage could be summarized as three parts, including the windborne debris risk analysis, debris flying trajectories, and impact resistance of the envelopes analysis. The debris source regions are graded based on the environment around the structures and the distributed degree of the buildings; meanwhile, the method of debris distribution is developed. According to the different aerodynamic characteristics, the flying trajectories of plate-like debris are solved by using numerical method; furthermore, the numerical results are compared with the test data and numerical solutions of the literature and show a good agreement. The trajectory equations of compact debris are improved by considering the vertical wind load caused by a wind attack angle, which accords with the real typhoon situation better. The impact resistance of the envelopes is analyzed. Besides, the process of windborne debris damage analysis is described in detail. An example of industrial building is given to demonstrate the whole method by using the observed data of typhoon Chanchu （No.0601）. The method developed in this paper could be applied to the risk assessment of windborne debris for structures in wind hazard.