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

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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.