台风“布拉万”远端风场阵风特性分析

Gust characteristic analysis of wind field at the periphery of typhoon ‘Bolaven'

基于安装于西堠门大桥上的风速仪收集到的台风"布拉万"远端风场风速资料,分析了"布拉万"过境时桥址处平均风速、风向和紊流特性的变化,重点探讨了不同计算时距条件下阵风因子的分布概型及其均值、极值的变化规律,研究结果表明:台风"布拉万"远端风场紊流强度和阵风因子随平均风速的增大而减小,高风速下顺风向紊流强度为0.18,大于桥梁抗风规范建议值,且横风向和竖向风速相对脉动强度均比桥梁抗风规范值小;台风"布拉万"远端风场顺风向、横风向和竖向的阵风因子均服从广义极值分布,随着计算时距的增大其分布概型逐渐由极值Ⅲ型转变为极值Ⅱ型,且95%保证率条件下顺风向阵风因子与建筑结构抗风规范取值一致;台风"布拉万"远端风场阵风因子随阵风计算时距的变换规律可以用对数高斯函数加以描述。

Base on long-time-measured data of typhoon‘Bolaven’recorded at the Xihoumen Bridge,wind characteristics,such as wind speed,wind direction,turbulence intensity,probability distribution and its extreme and average value of gust factor under different averaging time periods were investigated.It was shown that the turbulence intensity and gust factor of Balaven were decreasing with average wind speed in three directions,and that the mean statistical result of turbulence intensity related to longitudinal fluctuation components was 0.161 at high wind speed,which was higher than the recommended value.The gust factor analysis results show that the probability distribution of gust factor is converted from extreme value type III to type II with gust averaging time,and the statistical value of gust factor at 95%confidence level is identical to the recommended value in load code for the design of building structures.It is also discovered that Logarithmic Gauss distribution function can be used to describe the relationship between gust factor and its corresponding time interval.