基于渐进破坏的单个和区域低矮房屋风灾易损性分析

Low-rise buildings belongs to wind-vulnerable structures. In the strong winds such as typhoons, they suffer from the serious damages. Due to the wide existence, the damage of low-rise buildings is the main contributor to the huge losses caused by the wind. Therefore, its vulnerability analysis under winds has important engineering significance. At present, there are few systematic studies on vulnerability analysis of low-rise buildings, and little consideration is given to its progressive failure. ..Based on typical low-rise building models, we will measure the internal and external wind pressures in the three stages of the progressive failure process via the wind tunnel test and study the changes of the wind pressure, especially the internal pressure. Using the existing very long wind pressure data, we will develop the extreme value calculation formula with high precision and simplicity, and establish the model to characterize the correlation among extreme values. Considering the correlation of the extreme wind pressure, the building envelope damage by the debris and the wind meteorological data on the building location, we will establish the progressive failure -based wind vulnerability model for the single building. Taking the typhoon in the coastal area in China as an example, we will obtain the wind information at the incident location by calculating and simulating the typhoon wind field; further we will develop the vulnerability model for the low-rise buildings at a region based on the numerical simulation and wind tunnel test to study the effect of building disturbance. The study will not only improve the resilience of the low-rise buildings, but also provide a scientific basis for disaster prevention and risk control in government, industry and the insurance industry.

低矮房屋属于风灾易损结构，在强风下，易受严重破坏。由于量大面广，低矮房屋破坏是风灾造成巨大损失的主要原因。因此，其风灾易损性分析具有重要的工程意义。目前针对低矮房屋的风灾易损分析的系统研究较少，而且很少考虑其渐进破坏。..基于典型房屋模型，通过风洞试验，对渐进破坏过程中的三阶段进行风压测量，研究各个阶段中风压特别是内压变化情况。利用已有的超长风压数据，发展出精度高又简易的极值计算公式，并对极值相关性进行建模。在考虑风压极值相关性及房屋围护结构遭受飞掷物破坏的基础上，结合房屋所在地的风速气象资料，建立基于渐进破坏的低矮房屋风灾易损性分析模型。以我国沿海地区台风为例，通过台风风场计算和模拟，获得事发地的台风信息，并在利用数值模拟和风洞试验研究房屋干扰效应基础上，发展区域房屋风灾易损性模型。该项研究不仅可以提高房屋的抗灾能力，也可为政府、工业界及保险业等提高防灾及风险控制能力提供科学依据。

我国遭受风灾最多的国家之一。低矮房屋属于风灾易损结构，在强风下，易受严重破坏甚至整体倒塌。由于低矮房屋量大面广，其破坏是造成巨大风灾损失的主要原因。因此，其风灾易损性分析具有重要的工程意义。本项目首先提出了台风风场计算和模拟的新方法，以更准确高效的获得事发地的台风信息。其次基于超长风压数据，提出了精度高又简易的极值风压计算公式。最后在考虑风压极值相关性及房屋围护结构遭受飞掷物破坏的基础上，建立了基于渐进破坏的低矮房屋风灾易损性分析模型。主要取得了如下成果：.1) 基于Arya边界层模型提出了改进的台风风场经验模型，并在模拟圆半径、中心气压差和台风关键参数相关性三个方面对传统台风局部路径模型进行了改进。.2)提出了基于Hermite矩模型、直接利用高阶矩计算风压极值的简易公式。相对于传统基于非线性方程组的求解方法，该公式可提高精度20-30%。.3) 建立了基于Johnson传递模型（JTM）对非高斯风压的模拟框架，并基于JTM推导出了非高斯风压相关系数关于高斯风压相关系数的解析表达式，同时推导出了基于JTM估计峰值因子的解析式。.4) 利用风压或风致响应的多个样本，从其前四阶统计矩（均值、方差、偏度和峰度）的不确定性出发，推导了基于HPM 转换过程、可计算风效应极值任一分位点概率分布（或不确定性）的解析公式。.5) 考虑风压和飞掷物的耦合破坏、随机开孔、内压变化以及风效应不确定性等因素，利用条件概率，提出考虑结构渐进破坏过程的风灾易损性分析框架，为低矮房屋风灾风险分析提供了工具和手段。.该项研究的成果不仅可以提高房屋的抗灾能力，也可为政府、工业界及保险业等提高防灾及风险控制能力提供科学依据。基于Hermite矩模型的风荷载极值计算公式被《屋盖结构风荷载标准 JGJ/T 481-2019》采纳。基于渐进破坏过程的低矮房屋风灾易损性分析也被中国再保险集团旗下中再巨灾风险管理股份有限公司开发的“中国台风巨灾模型（再型）”采纳。