近地台风风场特性及低矮房屋风荷载现场实测研究

通过研制的可移动平坡屋面实验房风压及台风风场现场实测系统，研究近地台风风场特性和低矮房屋表面风荷载分布规律。基于实验房获取到的10余次近地台风风速和风压实测数据，对近地台风风场湍流特征参数如湍流强度、阵风因子、湍流积分尺度及脉动风速功率谱等，按来流不同方位地貌状况进行分类研究；同时分析了斜向强风最不利工况下，屋面角部区域风压分布特征。分析结果表明: A、B、C类地貌条件下，台风顺风向湍流强度均值分别为0.13， 0.21， 0.32；阵风因子同湍流强度正相关，湍流积分尺度随湍流强度增加而减少；与季风相比，台风眼壁区域的顺风向脉动风速功率谱密度值略大于季风的实测值，而横风向脉动风速功率谱密度值显著大于季风的实测值；在低频和惯性子区范围，台风眼壁区域的顺风向脉动风速von Karman和Harris谱拟合值与实测值吻合较好；在斜向风作用下迎风屋檐角部边缘测点区域具有较高峰值负压和脉动风压，峰值负压系数达-13.5。

Field measurement study on near ground wind characteristics and wind pressure of instrumented low rise building during typhoons

A full-scale instrumented moveable low-rise building was constructed and used to monitor wind velocity field and associated building surface pressures during typhoons. The major objective of the field study was to further understand typhoon-generated wind characteristics and wind pressure on the low-rise building under extreme wind conditions during typhoon landfalls. The field measurements of wind speed velocity and wind pressure on the low rise building were carried out during typhoons based on the field instrumented building system. This paper focuses on field study of wind characteristics in surface boundary layer and wind pressure distribution on roof corer zones. Wind turbulence characteristics such as turbulence intensities, gust factors and turbulence integral length scales were investigated relative to different terrain roughness regimes. Turbulence intensities increase with increasing surface roughness. The mean values of the longitudinal turbulence intensities (TI) are 0.13, 0.21 and 0.32 for the coastal terrain, open land terrain and suburban terrain, respectively. Gust factor increases with turbulence intensity increasing for three special roughness regimes. Turbulence integral scales are expected to decrease with increasing turbulence intensity. The spectra for longitudinal components of the typhoon and monsoon show similar energy distribution, whereas, the spectra for lateral wind component for winds within eye-wall region has significantly higher energy than those for monsoon. The observed spectrum for longitudinal component of the typhoon within eye wall region is close to the Von Karman’s model and Harris’s model in the lower and in the middle frequency regions. Moreover，detailed analysis of the mean, peak and standard deviation of pressures measured on a roof corner zone is conducted to investigate the pressure distribution characteristics on the roof corner zone. The windward leading edge on the corner is consistently subjected to the most severe suction pressures and fluctuation pressures for quartering winds. The minimum negative peak pressure coefficient is -13.5. 