Collaborative Research: Assessment of Tornado Loading on Low-Rise Buildings Using Computational Modeling and Tornado Simulator Testing

龙卷风是一种严重的风暴，多次对美国的建筑环境造成毁灭性的破坏。 特别是低层建筑，历史上一直是最容易受到龙卷风破坏的建筑物之一。这种类型的结构的故障通常是龙卷风造成的社会和经济损失的原因，包括生命和财产的损失，以及许多重要的社会功能的中断。阿肯色州大学（UARK）和德克萨斯理工大学（TTU）的这项合作研究的目标是进一步推进对低层建筑物龙卷风荷载的基本理解。本研究的结果可用于评估建筑物在龙卷风中的性能，设计新的抗龙卷风建筑物，并制定改造策略，以提高现有建筑物在龙卷风中的性能。该研究项目将与UARK和TTU的教育和宣传活动相结合，以提高公众对自然灾害（包括龙卷风）对建筑环境和社会的影响的认识。在UARK，学生将通过新生工程项目和乔治华盛顿卡弗研究项目参与研究，该项目为来自历史上黑人学院和大学的学生提供研究实习机会。在TTU，该项目将为风科学与工程博士生提供研究培训。程序. 这项研究还将与德克萨斯州拉伯克的恶劣天气意识日等项目相结合，并通过与当地K-12学校和国家组织的伙伴关系，如4-H青年发展和指导计划，向当地和国家社区推广。这些研究、教育和外展活动将有助于使美国社区更能抵御龙卷风灾害。为了实现研究目标，该项目将利用一种研究方法，将TTU龙卷风模拟器中的物理实验和UARK基于计算流体动力学（CFD）的数值模拟的互补优势相结合。与以往独立进行的实验和数值研究不同，本研究中的实验和计算模型将系统地协调。龙卷风模拟器中的定制实验将首先作为验证和改进计算模型在模拟近地面龙卷风样流和捕获这些流与通用结构形状之间的相互作用方面的能力的基础。然后，在龙卷风模拟器中验证的计算模型和附加实验将用于评估龙卷风引起的各种围护结构的低层建筑物上的力和压力。根据涡流比和最大平均切向速度与平移速度比，将考虑各种结构的龙卷风。本研究的主要结果将以压力和力系数的形式作用于不同的建筑形状。这些系数以及原始数据和元数据将在UARK和TTU存档，并通过NSF支持的自然灾害工程研究基础设施数据库（https：//www.designsafe-ci.org/）提供给自然灾害工程界。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Tornadoes are a type of severe windstorm that repeatedly have caused devastating damage to the built environment in the United States. Low-rise buildings, in particular, historically have been among the structures that are the most vulnerable to tornado damage. Failures of this type of structure are often responsible for the social and economic losses caused by tornadoes, including the loss of life and property, as well as the interruptions to many critical societal functions. The goal of this collaborative research at the University of Arkansas (UARK) and Texas Tech University (TTU) is to further advance the fundamental understanding of tornadic loading on low-rise buildings. The outcomes of this research can be used for the assessment of building performance in tornadoes, the design of new tornado-resistant buildings, and the development of retrofitting strategies to improve the performance of existing buildings in tornadoes. The research project will be integrated with educational and outreach activities at both UARK and TTU to raise public awareness of the impact of natural hazards, including tornadoes, on the built environment and society in general. At UARK, students will be involved in the research through the Freshman Engineering Program, and the George Washington Carver Research Program that provides research internships to students from Historically Black Colleges and Universities. At TTU, the project will provide research training for students in the Wind Science and Engineering Ph.D. program. The research will also be incorporated with programs such as the Severe Weather Awareness Day in Lubbock, TX, and through partnerships with local K-12 schools and national organizations, such as the 4-H Youth Development and Mentoring Program, to reach out to both local and national communities. These research, educational and outreach activities will help make U.S. communities more resilient to tornado hazards.To achieve the research goal, this project will utilize a research approach that combines the complementary strengths of physical experiments in a tornado simulator at TTU and numerical modeling based on computational fluid dynamics (CFD) at UARK. Unlike previous experimental and numerical studies that were conducted independently, the experiments and computational modeling in this research will be systematically coordinated. Customized experiments in the tornado simulator will first serve as the basis to validate and improve the capability of the computational model in simulating near-ground tornado-like flows and in capturing the interaction between these flows and generic structural shapes. The validated computational model and additional experiments in the tornado simulator will then be used to evaluate tornado-induced forces and pressures on low-rise buildings of various envelope configurations. Tornadoes of various structures, in terms of the swirl ratios and the maximum mean tangential velocity to translation velocity ratio, will be considered. The primary outcomes of this study will be in the form of pressure and force coefficients acting on different building shapes. These coefficients, as well as the raw data and the metadata, will be archived at both UARK and TTU and made available to the natural hazards engineering community through the NSF-supported Natural Hazards Engineering Research Infrastructure Data Depot (https://www.designsafe-ci.org/).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.