Investigation of Discrepancies in Laboratory Wind Loading Modeling and Development of Standardized Wind Tunnel Testing Protocol for Low Buildings

2005年的卡特里娜飓风和威尔玛飓风，以及近期的其他主要飓风和强风事件，都严峻地提醒人们，此类灾害的影响可能造成灾难性后果。为减少风害造成的生命和财产损失，需要采取社会行动，这一问题正在全国范围内展开辩论，因此制定了《国家减少风暴影响方案》，并制定了方案实施计划。这些努力导致了基础研究和应用研究的任务和子任务的确定，以及完成计划目标所需的研究实施活动。这些活动的关键成果之一是为现有建筑物和其他结构的抗风设计制定可靠的标准和规范，并对现有基础设施进行改造。这些准则的改进需要分析工具的进步和高保真风和风荷载数据库的利用。研究解决了低层建筑抗风设计中风荷载数据、气动数据库等的质量和可靠性问题。概述的努力建立在该领域最近取得的成就之上，这些成就是在NIST/TTU合作协议框架内开展的研究活动的结果。风暴缓解倡议，以及由NIST协调的低层建筑风荷载的实验室间比较研究。实验调查是科罗拉多州立大学（CSU）目前正在进行的研究活动的延伸。在计划的风洞测试中利用新获得的1024通道压力，将允许在开发的广泛风荷载数据集数据库中进行采集和分析。研究的具体目标是：(1)识别不同风工程实验室在过去的实验室测试中获得的风荷载变异性的来源及其对设计风荷载的影响；(2)制定标准化测试方案，以减少实验室风荷载的变异性；(3)对国家抗风设计气动数据库的贡献。实现这些目标的研究工作分为以下五个任务：(1)调查参与风洞实验室第一阶段测试中获得的风荷载差异；(2)风荷载变异性对低层建筑风效应的影响评估；(3)参与实验室进行第二期风洞研究；(4)参与实验室提供的第二期风荷载分析；(5)制定了确定低矮建筑风荷载标准风洞程序草案。描述的工作包括比较研究，在科罗拉多州立大学和参与的风工程实验室进行风洞测试，交换技术信息（包括两个研讨会），与参与的实验室和NIST的一个研究小组合作，以及共同开发测试方法和标准协议，以模拟低矮建筑物的风荷载。上述活动的更广泛影响包括制定和验证标准工具，以制定可靠的风力规定标准和规范，从而设计新的和改造现有建筑物（和其他结构），显著提高抗风能力。该研究的智力价值在于，在现有测试方法、经验模型和其他因素及其对设计风荷载的影响（以及相关的误差/近似值）中，识别出不一致和缺陷，并基于对物理现象的更好理解和先进实验和分析/数值工具的利用，开发出对这些限制的补救措施。

The 2005 experience with Hurricane Katrina and Wilma, as well as other major recent hurricanes and strong wind events, is a grim reminder of potentially catastrophic effects of impacts of such hazards. Ongoing national debate on societal action needed to reduce loss of life and property damage due to wind hazards led to establishment of the National Windstorm Impact Reduction Program and development of the program implementation plan. These efforts resulted in identification of tasks and subtasks for fundamental and applied research, and the research implementation activities needed to accomplish the program goals. One of the critical outcomes of such activities is development of reliable standards and codes for wind-resistant design of existing buildings and other structures, and retrofit of the existing infrastructure. Improvements in such guidelines require advancements in analytical tools and utilization of high fidelity wind and wind loading databases.The research addresses the issue of quality/reliability of the wind loading data, aerodynamic databases, etc., for wind-resistant design of low buildings. The outlined effort builds on recent accomplishments in this area, resulting from research activities carried out within the framework of the NIST/TTU Cooperative Agreement ? Windstorm Mitigation Initiative, and the inter-laboratory comparative study of wind loading on low buildings coordinated by NIST. The experimental investigations are an extension of current ongoing research activities at Colorado State University (CSU). Utilization of the newly acquired 1024-channel pressure in the planned wind tunnel testing will allow for acquisition, analysis of inclusion in the developed database of extensive wind loading datasets.Specific objectives of the research are: (1) Identification of sources of variability in wind loading acquired at various wind engineering laboratories during past laboratory testing and their effects on design wind loading; (2) Development of standardized testing protocol to reduce variability in laboratory wind loading; and (3) Contribution to national aerodynamic database for wind-resistant design. The research effort to address these objectives is divided into the following five tasks: (1) Investigation of Discrepancies in Wind Loading Obtained during Phase I Testing at Participating Wind Tunnel Laboratories; (2) Assessment of Impact of Variability in Wind Loading on Wind Effects on Low Buildings; (3) Development of Phase II Wind Tunnel Studies at Participating Laboratories; (4) Analysis of Phase II Wind Loading Provided by Participating Laboratories; and (5) Formulation of Draft Standardized Wind Tunnel Procedures for Determining Wind Loading on Low Buildings. Delineated work comprises of comparatives studies, wind tunnel testing at CSU and at participating wind engineering laboratories, exchange of technical information (including two workshops), collaboration with participating laboratories and a research team at NIST, and joint development of testing methodology and standardized protocol for tunnel simulation of wind loading on low buildings. The broader impact of the above activities includes formulation and validation of standardized tools for development of reliable wind provisions of standards and codes, leading to design of new and retrofit of existing buildings (and other structures) of significantly improved wind resistance. The intellectual merit in the study is the identification of inconsistencies and deficiencies in the existing testing methodologies, empirical models, and other factors and their effects on design wind loads (and associated errors/approximations), and the development of remedies to these limitations, based on improved understanding of physical phenomena and utilization of advanced experimental and analytical/numerical tools.