Review of the Need for a Large-Scale Test Facility for Research on the Effects of Extreme Winds on Structures (1999)

One extreme wind event-Hurricane Andrew in 1992-inflicted the largest direct and indirect economic losses (~$25 billion) ever experienced by the United States as the result of a natural disaster (AAWE, 1997a). Although Hurricane Andrew was an extreme weather event, hurricanes, tornadoes, and storm surges in the United States cause, on average, several billion dollars in damage and claim hundreds of lives annually (Jones et al., 1995). The United States has made great improvements in its detection, warning, and reporting capabilities for major storms, increased awareness of the vulnerability of certain types of structures, and taken steps to mitigate damage. Despite these advances, the fatalities and damage from devastating storms has been growing, with individual dwellings and low-rise commercial and industrial structures bearing the brunt of the damage (NRC, 1985; Cermak, 1998).

In an effort to reduce these losses, particularly the loss of life, a small community of engineers and scientists has been conducting research for some decades into the nature of wind-structures interactions with the goal of improving the performance of non-engineered structures. ¹ Although this research has led to some improvements in building codes and standards, materials selection, construction practices, and building inspection, major gaps remain in basic research and testing capabilities in wind engineering (Cermak, 1998).

Although several universities, private industries, and government laboratories have experimental and test facilities, no facility is capable of testing, to destruction, full-scale buildings of the type most prone to damage from extreme wind conditions (i.e., residences and non-engineered commercial buildings). Furthermore, even though large engineered structures have not suffered significant structural damage, the envelopes of these buildings are frequently seriously damaged by severe winds, causing considerable losses to contents and costly business interruptions.

The Idaho National Engineering and Environmental Laboratory (INEEL), through the U.S. Department of Energy (DOE), has proposed that a large-scale wind test facility (LSWTF) be constructed to determine the behavior of full-scale structures, including typical site-built and manufactured housing units, under extreme wind conditions in a controlled environment (INEEL, 1998). In order to determine the need for, and potential benefits of, such a facility, the Idaho Operations Office of the DOE requested that the National Research Council (NRC) perform an independent assessment of the role and potential value of an LSWTF in the overall context of research in wind engineering.

In response to that request, the NRC established the Committee to Review the Need for a Large-scale Test Facility for Research on the Effects of Extreme Winds on Structures under the

auspices of the Board on Infrastructure and the Constructed Environment. The committee was asked to perform the following tasks:

• review the need for a large-scale, experimental, wind engineering facility
• identify the potential benefits of such a facility
• assess the priority of large-scale physical testing as a component of a national wind engineering research program

In addressing these tasks, the committee considered the following issues:

• the need for large-scale, experimental data for a better engineering/scientific understanding of the effects of extreme winds on non-engineered structures
• the benefits of generating data on extreme winds in a controlled environment as a complement to collected field data or to post-storm assessments
• the value of data produced by large-scale, full-system testing compared to small-scale or component testing
• the value of large-scale testing data (as compared to observational data) in the development and validation of computer simulations as a vehicle for (1) public education, (2) the validation of current building codes, and (3) improvements in the design of credible, standardized, small-scale or single-component experiments

The 14 members of the study committee are renowned engineers and scientists with expertise in the following areas: wind-structure interactions, large-scale engineering research facilities, the performance of non-engineered structures, the characteristics of extreme winds, and wind-hazard reduction. Biographical information on the committee members is provided in Appendix A.

The committee met twice—once in December 1998 and once in January 1999. In light of the short time available to develop its findings and recommendations and issue a report, the committee drew heavily on the proceedings of three recent workshops and conferences on wind engineering (AAWE, 1997b; Marshall, 1995; O'Brien, 1996), two recent reports (AAWE, 1997a; NRC, 1993), and their own considerable experience. The committee also distributed a questionnaire to 75 researchers and practitioners in the fields of wind engineering, extreme wind events, and hazard mitigation. The questionnaires elicited 22 responses. The questionnaire, list of respondents, and synthesis of the responses are included in Appendix B. Although this report draws heavily on previously published work and responses to the questionnaire, the findings and recommendations were developed solely by the NRC committee that was specially appointed for this purpose.

The succeeding chapters in this report address the committee's charge in the following manner. Chapter 2 contains a discussion of the technical aspects of an LSWTF and summarizes

the committee's deliberations regarding the value of large-scale test data, wind-hazard research, uses and needs for large-scale testing, and the benefits and role of an LSWTF in wind engineering research. Chapter 3 is a discussion of economic considerations that the committee believes are relevant to an evaluation of an LSWTF. Chapter 4 contains the committee's findings and recommendations.