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

2005年卡特里娜飓风和威尔玛飓风以及最近的其他重大飓风和强风事件的经历是一个严峻的提醒，提醒人们这类灾害的影响可能产生灾难性影响。就减少风灾造成的生命和财产损失所需的社会行动进行的持续的全国辩论导致了国家减少风灾影响方案的建立和方案执行计划的制定。这些努力确定了基础研究和应用研究的任务和子任务，以及实现计划目标所需的研究实施活动。这类活动的关键成果之一是为现有建筑物和其他结构的防风设计制定可靠的标准和准则，并对现有基础设施进行改造。这类指南的改进需要改进分析工具和利用高保真的风和风荷载数据库。这项研究解决了用于低矮建筑物抗风设计的风荷载数据、空气动力学数据库等的质量/可靠性问题。概述的工作建立在这一领域的最新成就的基础上，这些成就是在NIST/TTU合作协议框架内开展的研究活动所产生的？减少风暴倡议，以及由NIST协调的低矮建筑物上风荷载的实验室间比较研究。这些实验研究是科罗拉多州立大学(CSU)目前正在进行的研究活动的延伸。在计划中的风洞测试中利用新获得的1024通道压力将允许获取、分析包含在开发的广泛风荷载数据集的数据库中。研究的具体目标是：(1)确定在过去的实验室测试期间在各个风工程实验室获得的风荷载的变化性来源及其对设计风荷载的影响；(2)制定标准化测试规程以减少实验室风荷载的变异性；以及(3)为国家抗风设计的空气动力学数据库做出贡献。针对这些目标的研究工作分为以下五项任务：(1)调查在参与的风洞实验室进行第一阶段测试期间获得的风荷载差异；(2)评估风荷载的可变性对低矮建筑物的风影响；(3)在参与实验室开展第二阶段风洞研究；(4)由参与实验室提供的第二阶段风荷载分析；以及(5)制定确定低矮建筑物风荷载的标准风洞程序草案。所描述的工作包括比较研究，在CSU和参与的风工程实验室进行风洞测试，交流技术信息(包括两个研讨会)，与参与实验室和NIST的一个研究小组合作，以及共同开发测试方法和低层建筑风荷载的隧道模拟标准协议。上述活动的更广泛影响包括制定和验证用于制定可靠的风力标准和规范的标准化工具，导致设计新的和翻新的现有建筑物(和其他结构)，使其抗风性能显著提高。这项研究的智力价值在于识别现有测试方法、经验模型和其他因素及其对设计风荷载(和相关误差/近似值)的影响中的不一致和不足之处，并基于对物理现象的更好理解和先进实验和分析/数值工具的使用，开发针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.