Prediction and reduction of typhoon wind damage to residential houses

首先，调查了1991年第19号台风(9119号台风)袭击东北地区并造成严重风灾对民居造成的破坏。结果表明，损伤主要集中在面层，尤其是屋面材料。在此基础上，建立了风灾对面层破坏的随机预测模型。该模型由台风模型、局地气压模型和风阻模型组成。为了建立台风模式，对1954~1996年袭击东北地区的68个台风的气压分布进行了统计分析和描述。台风参数随时间的变化规律。37~42°N用简单的时间函数近似。利用这个台风模型进行计算机模拟，可以定量地了解台风大风的统计特征。采用多元回归分析方法研究了地形因子对风速的影响。在局部压力模型中，根据已有的风洞试验结果，将屋面几何形状分为两组，即山形屋面和髋部屋面，并为每组指定了局部压力系数。用准稳态方法预测了峰值压力的大小。因此，将该模型与台风模拟结果相结合，得到了局地峰值气压的概率密度函数。在覆层风阻模型中，覆层强度的概率密度函数被假定为对数正态分布，由9119号台风对覆层的损伤率来预测平均值。最后，给出了以广崎市为例进行的覆层破坏模拟结果，并讨论了屋面的风害特征。

First, an investigation was made of the damage to residential houses due to Typhoon No.19 in 1991 (Typhoon 9119), which struck Tohoku District and caused severe wind damage. The results indicate that most damage was caused to cladding, in particular to roofing materials.Then, a stochastic model for predicting the typhoon wind damage to cladding has been developed. The model consists of 'typhoon model', 'local pressure model' and 'wind resistance model'. For constructing the 'typhoon model', the statistical characteristics of the atmospheric pressure patterns of 68 typhoons, which struck Tohoku District during the period of 1954 to 1996, were analyzed and specified. The variations of the typhoon parameters with time between lat. 37 to 42o N were approximated by simple functions of time. Based on a computer simulation using this 'typhoon model', the statistical characteristics of strong winds due to typhoons can be understood quantitatively. The effects of topographic factors on wind speeds were investigated by using a multivariate regression analysis. In the 'local pressure model', the roof geometry is classified into two groups, i.e.gable and hip roofs, and the local pressure coefficient is specified for each group, based on the results of the previous wind tunnel experiments. The value of the peak pressure is predicted by a quasi-steady approach. Therefore, the probability density function of the local peak pressures is obtained by combining this model with the results of the typhoon simulation. In the 'wind resistance model' of cladding, the probability density function of the strength of cladding is assumed to be represented by the log-normal distribution ; the mean was predicted from the damage rate of cladding due to Typhoon 9119.Finally, the results of a damage simulation made for Hirosaki City are presented and the characteristics of the wind damage to roof are discussed.