Design wind loads for houses in tornadoes

龙卷风中房屋的设计风荷载

• 批准号: 493382-2015
• 负责人: Kopp, Gregory
• 金额: $ 5.17万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=655880
• 关键词: Design; wind; loads; houses; tornadoes

Economic and insured losses due to severe storms continue to grow, both in Canada and around the world. Canada is vulnerable to severe wind storms, with significant examples being the Barrie tornado in 1985 (12 lives, $300M), the Edmonton tornado in 1987 (27 lives, $670M), and Hurricane Juan in 2003 (8 lives). Wood-frame houses, our most common type of structure, are vulnerable because of the fact that most houses are not engineered and have limited wind-resistant features. The primary safety issue pertains to keeping the whole house on the foundation, and the roof connected to the walls. When this is achieved, loss of life and economic losses are minimized.** Wind effects on houses in large-scale storms, such as hurricanes, are now reasonably known because of many years of wind tunnel studies and, more recently, structural testing of full-scale structures along with building components and materials. It is well established that enhanced building codes can reduce losses in these storms. In contrast, wind loads on houses in tornadoes are largely unknown. Notwithstanding the fact that design to mitigate losses in tornadoes is only just beginning to be discussed due to the ever increasing losses, the fact that there are few facilities which can create tornado-like vortices of large enough size that buildings can be tested has also been a barrier. This has changed recently, with the development of the WindEEE Dome. The objective of this proposal is to use this facility as a basis to determine design wind loads for wood-frame houses in tornadoes. In particular, the effects of the (i) shape of the house, the (ii) surrounding terrain and (iii) neighbourhood patterns, along with the (iv) static-pressure drop and internal pressures, on wind loads will be examined in the presence tornado-like vortices. Design wind loads will be based on using a series of factors for each of these parameters, relative to those currently used in building codes. This approach will simplify design for practicing engineers and allow codes to be modified as other factors become more well understood. At least five students will be trained during the course of this investigation.****

在加拿大和世界各地，由于严重风暴造成的经济和保险损失继续增加。加拿大容易受到严重的风暴，重要的例子是1985年的巴里龙卷风（12人死亡，3亿美元），1987年的埃德蒙顿龙卷风（27人死亡，6.7亿美元）和2003年的胡安飓风（8人死亡）。 木结构房屋，我们最常见的结构类型，是脆弱的，因为事实上，大多数房屋没有工程，并有有限的抗风功能。主要的安全问题涉及到保持整个房子的基础上，屋顶连接到墙壁。做到这一点后，生命损失和经济损失将降至最低。 由于多年的风洞研究以及最近对全尺寸结构沿着建筑构件和材料的结构测试，现在已经合理地了解了大规模风暴（如飓风）中风对房屋的影响。众所周知，加强建筑规范可以减少这些风暴中的损失。相比之下，龙卷风中房屋的风荷载在很大程度上是未知的。尽管由于损失不断增加，减轻龙卷风损失的设计才刚刚开始讨论，但很少有设施可以产生足够大的龙卷风样漩涡，以测试建筑物，这也是一个障碍。最近，随着风之穹顶的发展，这种情况发生了变化。本提案的目的是利用该设施作为基础，以确定龙卷风中木结构房屋的设计风荷载。特别是，（i）房子的形状，（ii）周围的地形和（iii）邻里模式的影响，沿着（iv）静压降和内部压力，在风荷载将在龙卷风般的漩涡的存在下进行检查。设计风荷载将基于对这些参数中的每一个使用一系列系数，相对于目前在建筑规范中使用的那些。这种方法将简化工程师的设计，并允许代码修改，因为其他因素变得更好地理解。在调查过程中，至少有五名学生将接受培训。