大跨度金属屋面风荷载、抗风承载力和风致疲劳性能研究

The recent frequent occurrence of wind induced damage incidents of large span metal roof buildings makes the wind damage issue of such structures become the focusing topic of researchers. The main reasons of these wind damages include the underestimation of wind loads on metal roofs, negligence of wind fluctuation caused fatigue effects, lack of the understanding of high negative pressure induced by sensitive aerodynamics shapes and necessary control measures and the deficiency in the wind resistance design and construction. The objectives of this research project are to study the wind flow and pressure distribution behaviours of super large span roof structures through wind tunnel tests and CFD simulations and develop computational methods for the estimation of maximum and minimum wind pressures. The methods for the determination of segmental model for the study of local wind pressure of large span roof will be developed and systematic investigations on the aerodynamic wind resistance measures for reducing high negative roof pressure will be carried out..This research project also adopt physics and numerical methods to study the damage mechanisms of metal roof under the static and dynamic wind pressure and develop computational methods for equivalent loading series. With the equivalent loading series, the experimental study on fatigue effect of metal roof will be carrid out and compared with the numerical analysis method. The damage accumulation estimation method for metal roof structures including the effects of the characteristics of wind pressure and wind climate will be established. Accordingly, the basic methods and suggestions to improve the anti-fatigue behaviours and wind resistance capacity of large span metal roof buildings will be proposed. The accomplishment of this project will significantly contribute to basic scientific understandings and improvement of technical guidelines for the wind-resistant design of large span metal roof structures.

近年频频出现大跨度金属屋面风灾事故使得此类结构的风灾问题成了备受风工程研究者关注的焦点问题。屋面风荷载被低估、没考虑脉动风所引起的屋面疲劳效应、风敏感性气动外形引起的高负压和必要控制措施的缺失、屋面抗风设计及施工方面存在的问题是金属屋面致灾的主要原因。本项目拟通过风洞试验和CFD方法研究不同平面尺度和高度的大跨度屋盖的流动和风压分布规律，研究极值风压估计的计算方法；确定研究大跨度屋盖局部风压的模型节段方法并依此开展系统性气动抗风措施减缓屋面高负压值的研究。采用物理和数值方法研究金属屋面在静、动态风压作用下效应及破坏机理，研究等效循环荷载序列的计算方法，依此开展金属屋面疲劳效应试验研究并与数值分析方法进行对比；建立考虑风压及风气侯特征的金属屋面损伤累计估计方法。最终提出提高金属屋面风致疲劳性能和抗风承载力的方法和建议。通过研究推进金属屋面抗风设计的技术进步，为此类结构的抗风设计提供技术支撑。

在基金项目（51778243）支持下对大跨度金属屋面风荷载、抗风承载力和风致疲劳性能开展系统性研究，内容包括：1).建筑围护结构极值风压估计方法；2).缩尺比、风场湍流参数、风场类型对屋面风压分布特征试验结果的影响，屋盖风敏感区域的风压分布特征；3).建筑局部外形对大跨度屋盖风压分布的影响；4).大跨度屋盖风致内压的深化研究；5).屋面板的抗风承载力、正常使用状态屋面板失效准则；6).可用于金属屋面疲劳损伤寿命估计的荷载等效加载方法；7).设计使用寿命内金属屋面风致疲劳损伤的估计方法；8).大跨度平屋面风压场的湍流特征，结构风振响应的高效计算和等效静风压计算方法；9).完成多个大跨度屋盖项目的结构抗风试验研究，参编两本规范。项目主要贡献如下：.1).解决了长期以来风压时程样本独立性缺乏有效判据的难点，提出一种具有普适性、精度高和统计稳定的建筑围护结构极值风压估计方法；2).定量分析了缩尺比、湍流参数、风场类型对屋面风压分布特征试验结果的影响规律，提出了屋盖风敏感区域风压的取值建议；3).总结了建筑不同外形变化对大跨度屋盖结构风压分布的影响规律，验证了节段模型试验的有效性；4).提出改进屋盖风致内压试验精度的新方法，获取背景孔隙率对名义封闭下建筑风致内压的影响规律,提出多腔体风致内压的计算方法；5).提出自攻螺钉型、直立锁边型屋面板型正常使用状态下抗风承载力公式及其正常使用状态的失效准则；6).提出可用于金属屋面疲劳损伤寿命估计的等效荷载加载序列；7).提出设计使用寿命内金属屋面风致疲劳损伤的估计方法；8).提出基于Ritz-POD的谐波激励法和基于风压的荷载等效方法，显著提高了大跨度屋盖结构风振响应计算和结构抗风设计的效率。.本项目部分成果已被用于相关规范。迄今为止发表论文10篇、获发明专利授权4项、参编行业和地方规范2本、软著2项、获省级行业协会科技奖特等奖1项。