台风作用下低矮建筑内外风压现场实测和风洞试验研究

In this proposal project, a full-scale gable roof instrumented low-rise building has been constructed and implemented to monitor wind velocity field, associated building surface pressures and fluctuating internal pressures arising from a dominant opening on a windward wall during typhoons.The major objective of the field study is to further understand near ground typhoon-generated wind characteristics and extreme net wind loads on the low rise builidng under strong wind conditions.Field measurement study are conducted to invstigate the surface wind turbulence characteristics and the mechanism for generation of flucating internal pressues and the assoiate extrem wind loads on gable roof base on the pressure data and wind velocity data recorded from the instrumented low-rise building. The reliability and precision of the proposal formulation for internal pressures building with a dominant opening in a wall can be examined base on field study results under extreme windstorm. The net wind loads designed method for the wind-resistant design of low-rise buildings in typhoon-prone regions considering wind-induced internal pressure is proposed. On the other hand,wind tunnel tests are conducted to assess the external and internal wind loads on the experimental buildings.Moreover,detailed analysis of the mean, fluctuating and negative peak pressures measured on the roof and wall is conducted to investigate the external and internal pressure characteristics. The model test results are compared to the full scale measurements to evaluate the applicability and accuracy of the wind tunnel simulations. Furthermore, full scale and model scale pressure measurement are performed to evaluate the effectiveness of parapets mounted at the roof-edge on mitigating these high suctions.The building aerodynamic and mechanical measures of the wind-resistant design of low-rise buildings are suggested. The outputs of the project are expected to provide useful information and reference on the net wind loads determination for the wind-resistant design of roof sheathing panels on low-rise buildings in typhoon-prone regions.

本项目通过创建低矮建筑内、外风压测试及台风观测现场实测系统（实验房），开展近地台风风场、低矮建筑表面风压和突然开孔状况结构内部风致压力等信息现场实测研究；基于现场实测研究，揭示近地台风风场特性、低矮建筑极值风荷载和风致内压脉动机理及净风荷载；建立突然开孔结构风致内压方程，并验证方程的可靠性和精确性；提出台风作用下考虑风致内压效应的低矮建筑净风荷载计算方法；同时开展低矮建筑内、外风压风洞实验研究，获得详细的低矮建筑外部风压和内压结果，以现场实测研究结果为基础，比较分析风洞实验结果与现场实测结果差异，评估低矮建筑（内、外风压）风洞实验技术的适用性和准确性；最后综合应用现场实测和风洞实验，系统研究了实验房屋面布设建筑构造措施的减风效应，提出相应的建筑抗风构造措施；研究成果可为台风地区低矮建筑的覆盖物及构件的抗风设计提供参考。

项目针对台风风致灾害中低矮建筑的风损和风毁问题，应用现场实测、风洞实验及理论分析相结合的方法，对台风作用下近地台风风场特性和低矮建筑风荷载进行了深入、系统的研究。主要研究内容及成果：.（1）选取台风和季风风场强风样本，应用Bootstrap统计分析法，开展强风条件下近海岸地貌和开阔平坦地貌100m高度范围内平均风剖面参数研究，结果表明A、B类场地台风风场近地平均风剖面符合指数律或对数律，台风风剖面指数分别约为0.12和0.15，与现行规范相吻合。.（2）基于双坡屋面实验房获取的台风风速和双坡屋面表面风压同步实测数据，对双坡屋面风压分布规律进行了研究。迎风屋面屋脊角部边缘测点、屋檐角部区域具有较高的局部峰值负压和脉动风压，风压系数的概率分布为非高斯分布。屋檐和屋脊角部区域的峰值负压系数的实测值及极值分析的结果与ASCE 7-10规范规定值进行了比较，发现ASCE 7-10规范低估了屋檐和屋脊角部边缘区域的峰值负压。.（3）以平坡屋面和双坡屋面实验房现场实测结果为基准，开展了两实验房的1:4大比尺模型测压风洞试验研究。不同比例尺模型屋面屋檐和屋脊区域的峰值负压及脉动风压，实验值与现场实测值存在较大差异，1:4模型屋面屋檐和屋脊区域的峰值负压和脉动风压风洞实验结果与实测值相接近。同时开展了1:20不同流场条件、不同坡度屋盖形式和屋面建筑构造对屋面风荷载影响的相关风洞实验研究。.（4）基于现场实测研究结果，应用准定常理论分析了屋面角部区域的等效静态风压系数、脉动风压系数和脉动风压谱。根据香港天文台横澜岛观测站实测台风风速资料，考虑各年台风发生频次不同，运用复合极值Poisson-Gumbel模型分析了台风多发地区的极值风速。结合等效静态风压系数和极值风速分析结果，分析了台风多发地区的低矮建筑平坡屋面的极值风压。