Wind Load Factors for Use in the Wind Tunnel Procedure
Publication: ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering
Volume 3, Issue 4
Abstract
Published standards may be incomplete because they provide no guidance on wind load factors appropriate for use with the wind tunnel procedure. The purpose of this paper is to contribute to such guidance. Based on a classical definition of wind load factors as functions of uncertainties in the micrometeorological, wind climatological, aerodynamics, and structural dynamics elements that determine wind loads, the paper presents a simple, straightforward approach that allows practitioners to use appropriate wind load factors applicable when those uncertainties are either the same as or different from those assumed in the standard. Illustrations of the approach are presented for a variety of cases of practical interest. In estimating design wind loads, the various uncertainties should not be accounted for in isolation, for example, by specifying peak pressure coefficients with percentage points higher than those corresponding to their expected values. Rather, to achieve risk-consistent designs, the uncertainties should be accounted for collectively, in terms of their joint effect on the design wind loading. The design wind effect is equal to the estimated expectation of the peak wind effect times a load factor that, in most cases, is not significantly different from the load factor explicitly or implicitly specified in the standard. Notably, the load factor is not affected significantly by errors associated with interpolations required in typical database-assisted design applications. However, if the available wind speed records are several times shorter than 20 to 30 years, for example, the wind load factors increase by approximately 15%.
Get full access to this article
View all available purchase options and get full access to this article.
References
ASCE. (2010). “Minimum design loads for buildings and other structures.” ASCE/SEI 7-10, Reston, VA.
Ellingwood, B., Galambos, T. V., MacGregor, J. G., and Cornell, C. A. (1980). “Development of a probability based load criterion for American National Standard A58.”, National Bureau of Standards, Washington, DC.
Fritz, W. P., et al. (2008). “International comparison of wind tunnel estimates of wind effects on low-rise buildings: Test-related uncertainties.” J. Struct. Eng., 1887–1890.
Gabbai, R. D., and Simiu, E. (2014). “Evaluation of mean recurrence intervals of wind effects for tall building design.” J. Struct. Eng., .
Gumbel, E. J. (2004). Statistics of extremes, Dover, New York.
Habte, F., Gan Chowdhury, A., Simiu, E., and Yeo, D. (2015). “Wind directionality factors for non-hurricane and hurricane-prone regions.” J. Struct. Eng., .
ISO. (2009). “Wind actions on structures.”, Geneva.
Lieblein, J. (1974). “Efficient methods of extreme-value methodology.”, National Bureau of Standards, Washington, DC.
Long, F. (2005). “Uncertainties in pressure coefficients derived from full and model scale data.” National Institute of Standards and Technology, Dept. of Civil Engineering, Texas Tech Univ., Lubbock, TX.
Main, J. A., and Fritz, W. P. (2006). “Database-assisted design for wind: Concepts, software, and examples for rigid and flexible buildings.”, National Institute of Standards and Technology, Gaithersburg, MD.
Mooneghi, A. M., Irwin, P. A., and Chowdhury, A. G. (2015). “Partial turbulence simulation method for small structures.” Proc., 14th Int. Conf. on Wind Engineering, Tokyo Polytechnic Univ., Atsugi, Kanagawa, Japan.
NIST. (2011). “Following the federal building and fire investigation of the World Trade Center disaster.” ⟨http://www.nist.gov/el/disasterstudies/wtc/upload/WTCRecommendationsStatusTable.pdf⟩ (Aug. 8, 2011).
Simiu, E. (2011). Design of buildings for wind, Wiley, Hoboken, NJ.
Simiu, E., and Scanlan, R. H. (1996). Wind effects on structures, 3rd Ed., Wiley, Hoboken, NJ.
SOM (Skidmore Owings and Merrill LLP). (2004). “Report on estimation of wind effects on the World Trade Center towers.” ⟨http://wtc.nist.gov/NCSTAR1/NCSTAR1-2intex.htm⟩ (Feb. 22, 2017).
Vickery, B. J. (1970). “On the reliability of gust loading factors.” Proc., Technical Meeting Concerning Wind Loads on Buildings and Structures, Building Science Series 30, National Bureau of Standards, Washington, DC.
Yeo, D., and Simiu, E. (2011). “High-rise reinforced concrete structures: Database-assisted design for wind.” J. Struct. Eng., 1340–1349.
Information & Authors
Information
Published In
Copyright
©2017 American Society of Civil Engineers.
History
Received: Mar 31, 2016
Accepted: Jan 6, 2017
Published ahead of print: Apr 2, 2017
Published online: Apr 3, 2017
Discussion open until: Sep 3, 2017
Published in print: Dec 1, 2017
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.