低矮建筑易损区风载定量与风致破坏机理研究

Local damage at the vulnerable area or its induced overall damage of the whole building are the two main modes of wind-induced damage of low-rise buildings. Therefore, it is very important for the wind-resistant design of low-rise buildings to reveal the wind-induced failure mechanism and evaluate wind load at the vulnerable area. However, wind loads at the vulnerable are affected by lots of factors, thus restricting the evaluation of wind load. Based on the field measurements achievements of low-rise buildings at the southeast coastal regions of China, wind tunnel tests, numerical simulation as well as field measurements are employed in this project to study the effects on the wind load characteristics of low-rise buildings caused by the wind characteristics parameters (including wind speed, wind direction and turbulence), slope angle of roof and structure of cornice, interferences and openings at the vulnerable area. The content of this project includes establishing wind pressure distribution model, determining the evaluation method of wind load at the vulnerable area, proposing the mathematical model for the wind-induce internal pressure resulted from the openings at the vulnerable area, revealing wind-induced failure mechanism of low-rise buildings and presenting the optimization method for wind-resistant design of low-rise buildings. The aim of this project is to reveal the wind induced failure mechanism of low-rise buildings, and provide theoretical foundations for the wind-resistant design and optimal design of low-rise buildings. The research achievements are of great importance and social significance and can be referred for similar projects.

低矮建筑损毁主要为低矮建筑局部损坏（简称易损区）或易损区破坏诱发建筑整体损毁，因此，揭示易损区风致破坏机理与定量表达易损区风载是低矮建筑抗风设计有效途径。然而，低矮建筑易损区风载影响因素众多，这制约了易损区风载定量评估。本项目借鉴已有近海海岸低矮建筑实测研究经验与成果，采用现场实测、风洞试验与数值模拟等研究方法相结合的手段，综合研究风特性参数（含风速、风向及湍流度）、屋面坡角、檐口构造、建筑群间相互干扰与易损区开洞等因素对低矮建筑风载特性影响规律，建立低矮建筑表面风压分布模型，确立易损区风载评估方法，建立易损区风载定量表达模型，构建易损区开洞所致低矮建筑风致内压计算模型，揭示低矮建筑易损区风致破坏机理，提出低矮建筑抗风设计优化措施。项目旨在揭示低矮建筑易损区风致破坏成因，为低矮建筑抗风设计所需的风载定量计算与抗风优化提供理论依据，研究成果具有重要的现实及社会意义。

近年来，登陆及影响我国沿海地区的台风频率及强度呈现逐年递增趋势。历次风灾统计表明，低矮建筑损毁所造成的损失超过风灾总损失的半数，低矮房屋风毁主要表现为屋面转角、边缘和屋脊等部位（统称为易损区）损坏，因此，低矮建筑易损局域风载定性研究及其评估分析尤其重要。. 本项目以沿海实测低矮建筑相关成果为指导，验证并确定低矮建筑风洞试验与数值模拟方法的定量分析低矮建筑风载模型，开展低矮建筑风致破坏机理研究。基于项目负责人4m×4m×6m原型实测房研究模型，按1:20缩尺设计了0°、9.6°、18.4°、30°、45°五类坡角的双坡低矮房屋刚性模型，综合考虑风特性参数（含风速、风向、湍流度及湍流积分尺度）、建筑群间相互干扰与易损区开洞等因素，定量评估并分析低矮建筑屋面风压分布特征及其变化规律，确立了低矮建筑屋面易损区。对低矮建筑易损局域（窗户与五类屋面易损区）单开洞及多洞口交叉开启所致内压响应展开了风洞试验及数值模拟研究，揭示了低矮建筑易损区风致破坏机理及易损局域损毁所致低矮建筑整体破坏成因。项目成果将为低矮建筑抗风设计及相关研究提供有价值的参考。