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

龙卷风是一种强烈的风暴，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之一。这种类型的结构的失败往往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。阿肯萨斯大学（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龙卷风荷载的基本理解。研究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，以及制定改进现有建筑物在龙卷风中的性能的改造策略。该研究项目将与新西兰皇家植物园和新西兰理工大学的教育和外展活动结合起来，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，该项目为来自传统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项目的学生提供研究培训。该研究还将与诸如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（如4-H青年发展和指导计划）的合作，向当地和国家社区延伸。这些研究、教育和推广活动将有助于使美国社区更能抵御龙卷风的危害。为了实现研究目标，该项目将采用一种研究方法，将TTU龙卷风模拟器物理实验的互补优势与UARK基于计算流体动力学（CFD）的数值模拟相结合。与以往独立进行的实验和数值研究不同，本研究将系统地协调实验和计算建模。龙卷风模拟器中的定制实验将首先作为验证和提高计算模型模拟近地类龙卷风流动以及捕获这些流动与一般结构形状之间相互作用的能力的基础。经过验证的计算模型和龙卷风模拟器中的附加实验将用于评估不同围护结构的低层建筑上的龙卷风诱导力和压力。在旋涡比和最大平均切向速度与平动速度比方面，将考虑各种结构的龙卷风。这项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，并通过美国国家科学基金会支持的自然灾害工程研究基础设施数据库（https://www.designsafe-ci.org/）.This)向自然灾害工程界提供，该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.