Benchmark Study of Tornado Wind Loading on Low-Rise Buildings with Consideration of Internal Pressure

龙卷风是美国历史上最具破坏性的自然灾害之一，如最近的主要龙卷风期间的破坏和死亡所观察到的，包括2011年密苏里州乔普林和亚拉巴马塔斯卡卢萨-伯明翰龙卷风，2013年俄克拉荷马州摩尔龙卷风和2015年德克萨斯州达拉斯地区龙卷风。正如龙卷风灾害后的调查一再显示的那样，龙卷风造成的损失和死亡往往是由于对低层建筑的破坏。 造成这种建筑物损坏的一个关键因素是，许多低层建筑物仅被设计用于主要沿沿着地球表面附近的直线行进的风，而不是用于可能更具破坏性的旋转龙卷风风，这主要是由于对龙卷风和结构上的龙卷风风载荷的理解不足。 本研究的目标是制定计算模型，全面表征旋转龙卷风风荷载和这种风荷载对低层建筑的影响。这些模型可以被工程师用来对遭受龙卷风危害的低层建筑进行基于性能的评估，以减少损失和死亡。为了提高人们对自然灾害（包括龙卷风）对建筑物和社区影响的认识，这项研究将被纳入德克萨斯理工大学（TTU）现有项目的教育和推广活动中，例如TTU国家风力研究所风科学与工程博士课程。计划和正在进行的外展活动，包括4-H辅导计划，科学营，和拉伯克的年度严重意识日。 为了实现这一研究目标，该项目将测试模型的低层建筑物的两种屋顶类型在各种类型的龙卷风涡模拟在一个大型龙卷风模拟器在TTU和直线风模拟在NSF支持的自然灾害工程研究基础设施（NHERI）边界层风洞在佛罗里达大学提供两个基准数据集。这两个数据集将被用来量化龙卷风和边界层类型的直线风的负载之间的差异。重点将放在建筑物内压的影响和龙卷风负荷的非平稳和非高斯性质的空间变化的风速和静压力赤字在龙卷风漩涡的翻译介绍。在此基础上，基于离散小波变换和高斯滤波的创新方法将被用来表征，建模和模拟非平稳，动态龙卷风风荷载的低层建筑，使概率评估的负载效果。项目数据将在NHERI数据库https://www.designsafe-ci.org/上提供。

Tornadoes are historically among the most devastating natural hazards in the United States, as observed by the damage and fatalities during recent major tornadoes, including the Joplin, Missouri and Tuscaloosa-Birmingham, Alabama tornadoes in 2011, the Moore, Oklahoma tornado in 2013, and the Dallas, Texas area tornado in 2015. As post-tornado disaster surveys have repeatedly revealed, tornado-induced losses and fatalities are often due to damage to low-rise buildings. A critical factor contributing to such building damage is that many low-rise buildings are designed only for winds that travel mostly along a straight line near the earth's surface, and not for the rotating tornado winds that are potentially more damaging, primarily due to inadequate understanding of tornadoes and tornado wind loading on structures. The goal of this research is to formulate computational models that comprehensively characterize rotating tornado wind loading and the impact of such wind loading on low-rise buildings. Such models can be used by engineers to conduct performance-based evaluation of low-rise buildings subjected to tornado hazard as a way to reduce damage and fatalities. To raise awareness of the impact of natural hazards, including tornadoes, on buildings and communities, this research will be integrated into education and outreach activities within existing programs at Texas Tech University (TTU), such as courses offered by TTU's National Wind Institute Wind Science and Engineering Ph.D. program and ongoing outreach activities, including a 4-H Mentoring Program, Science Camp, and Lubbock's Annual Severe Awareness Day. To achieve this research goal, this project will test models of low-rise buildings with two roof types in various types of tornadic vortices simulated in a large-scale tornado simulator at TTU and straight-line winds simulated in the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) boundary layer wind tunnel at the University of Florida to provide two benchmark datasets. These two datasets will be used to quantify the differences between the loadings by tornado and boundary-layer-type straight-line winds. The focus will be placed on the effects of building internal pressure and the nonstationary and non-Gaussian nature of tornado loading introduced by the translation of spatially varying wind speed and static pressure deficit in tornado vortices. On this basis, an innovative approach based on discrete wavelet transform and Gaussian filtering will be used to characterize, model, and simulate nonstationary, dynamic tornado wind loading on low-rise buildings to enable probabilistic evaluation of the loading effects. Project data will be made available in the NHERI Data Depot at https://www.designsafe-ci.org/.