Review of the Need for a Large-Scale Test Facility for Research on the Effects of Extreme Winds on Structures (1999) / Chapter Skim
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2 Technical Aspects of a Large-scale Wind Test Facility
2 Technical Aspects of a Large-scale Wind Test Facility
Pages 6-16
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From page 6... ...
, with a reasonable representation of atmospheric turbulence, over an area large enough to engulf a residential, single-family dwelling or other structure of similar size. The flow structure and size of the facility's wind stream would have to be sufficient to create a realistic flow around the structure and thereby generate appropriate and representative spatial and temporal variations of windinduced pressures.
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From page 7... ...
The reports emphasized that a coordinated national wind-hazard reduction program is necessary to mitigate wind-induced losses effectively, and they cautioned that an LSWTF alone would not provide answers to all outstanding questions in wind engineering (AAWE, 1997b; NRC, 1993~. Some existing facilities in the United States and abroad might be modified for large-scale wind testing (AAWE, 1997a)
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From page 8... ...
studies has shown that the gust structure of the wind plays an important role in the development of wind loads on structures. However, most of the existing field data on wind loads are limited to simple building shapes in open exposures subjected to winds generated by the passage of frontal systems rather than severe windstorms.
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From page 9... ...
For the purpose of reducing wind-hazards, an LSWTF would be most useful for conducting destructive experiments of large-scale structural systems, for fostering the development and validation of computational models, and for improving test methods. During the course of discussions and the review of responses to the questionnaire, the committee identified three topical investigations of buildings and structures that could be accomplished in an ESWTF: the performance of the building envelope, new construction techniques, and retrofitting technology.
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From page 10... ...
TABLE 2- ~ Technical Capabilities of a Large-Scale Wind Testing Facility (LSWTF) Building Tests Code Development and Validation Other Applications Instrumentation/Testing High Reynolds Number testing of structural components Water penetration experiments Destructive testing of fullscale systems, including relationships to SaffirSimpson Scale destruction categories Sheathing system tests and evaluations that include spatial loads Strong room evaluations for residential structures Fatigue of elements and connections in a full-scale system Window and roof system behavior relative to building envelope performance Internal pressure distributions on internal walls and ceilings Damage sensitivity to wind speed characterization (peak gust, sustained wind)
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From page 11... ...
Idealized Toads specified in building code provisions and simplified analytic procedures sometimes lead to design requirements that are inconsistent with the observed performance of buildings in severe windstorms. Development of improved component tests.
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From page 12... ...
Therefore, although an LSWTF would be an additional tool that could potentially help to improve design and construction technology, the effective transfer of the information produced by such a facility into practice would have to overcome similar barriers. Evaluating the efficacy of a wind engineering research method or facility requires first comparing its potential contributions with those of other experimental tools that could provide the same or equivalent information.
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From page 13... ...
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From page 14... ...
Therefore, a testing and certification mechanism should be established to assist manufacturers in qualifying proposed new items or concepts for improving the wind resistance of structures. To date, the experimental focus in wind engineering has been in the use of wind tunnels, mostly boundary-layer wind tunnels (Cermak, 1995~.
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From page 15... ...
. Because a large-scale test facility would be only one of many tools available to the wind engineering community, and one with specific capabilities and limitations, it would be prudent not to spend a disproportionate amount of the available funds in any given year on the construction, maintenance, and operating expenses of an ESWTF.
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From page 16... ...
Finally, there would have to be a clear understanding of how this facility and its research program and results would fit into a national wind-hazard reduction program.
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