Influence of Solid Area Distribution on the Drag of a Two-Dimensional Lattice Frame
Publication: Journal of Engineering Mechanics
Volume 140, Issue 3
Abstract
Many wind design codes provide recommended values of the drag coefficient for generic lattice frame geometries based on the solidity ratio. The solidity ratio of a lattice structure often varies along its length or height, resulting in a piecewise treatment in design. By definition, the solidity ratio is only dependent on the amount of solid area to the total enclosed area of a frame, and therefore does not account for member spacing or the number of members within the framework; this has implications for some nonuniform sections used in lattice tower design. Drag coefficients for many geometric configurations were measured in a wind tunnel with the focus placed on configurations having an identical solidity ratio but different member spacing ratios. It was observed that the drag coefficient varied with the member spacing ratio as well as with the number of members in the frame. The results suggest that the solidity ratio alone may not be sufficient for describing the drag coefficient of a lattice frame having a nonuniform solid area distribution. Recommendations are made for future research in this area, which may lead to better estimate of the drag coefficient for nonuniform lattice sections.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The author acknowledges the financial support of the National Sciences and Engineering Research Council (NSERC) of Canada. Many useful discussions with T. C. E. Ho and G. A. Kopp are also greatly appreciated. The author is grateful for the constructive comments provided by the three reviewers, which led to improvements in the paper.
References
ASCE. (1990). “Minimum design loads for buildings and other structures.” ASCE 7-88, Reston, VA.
ASCE. (2002). “Minimum design loads for buildings and other structures.” ASCE 7-02, Reston, VA.
ASCE. (2005). “Minimum design loads for buildings and other structures.” ASCE 7-05, Reston, VA.
ASCE. (2010a). “Guidelines for electrical transmission line structural loading.” ASCE manuals and reports on engineering practice No. 74, 3rd Ed., Reston, VA.
ASCE. (2010b). “Minimum design loads for buildings and other structures.” ASCE/SEI 7-10, Reston, VA.
ASCE. (2012). “Wind tunnel testing for buildings and other structures.” ASCE/SEI 49-12, Reston, VA.
Bayar, D. C. (1986). “Drag coefficients of latticed towers.” J. Struct. Eng., 417–430.
Bearman, P. W. (1971). “An investigation of the forces on flat plates normal to a turbulent flow.” J. Fluid Mech., 46(01), 177–198.
Biggs, J. M. (1954). “Wind loads on truss bridges.” Trans. Am. Soc. Civ. Eng., 119(1), 879–898.
Carril, C. F., Jr., Isyumov, N., and Brasil, R. M. L. R. F. (2003). “Experimental study of the wind forces on rectangular latticed communication towers with antennas.” J. Wind Eng. Ind. Aerodyn., 91(8), 1007–1022.
Clow, D. G. (1978). “Loads on open lattice structures: A comparative study.” Proc., 3rd Colloquium on Wind Engineering, Vol. 1, Fluid Mechanics Laboratory, Dept. of Aeronautics, Aachen, Germany, 165–177.
Cohen, E. (1957). “Design of multi-level guyed towers: Wind loading.” J. Struct. Div., 83(5), 1–29.
Engineering Science Data Unit (ESDU). (1982). “Lattice structures, Part 1: Mean fluid forces on single and multiple plane frames.” ESDU Data Item No. 81027, London.
Flachsbart, O. (1935). “Winddruck auf vollwandige bauwerke und gitterfachwerke.” Publ. Int. Assoc. Bridge Struc. Eng., 1, 153–172.
Georgiou, P. N., and Vickery, B. J. (1979). “Wind loads on building frames.” Proc., 5th Int. Conf. on Wind Engineering, Pergamon Press, Oxford, U.K., 421–433.
Hoerner, S. F. (1965). Fluid-dynamic drag, Hoerner Fluid Dynamics, Vancouver, WA.
Holmes, J. D. (1986). “Wind tunnel tests on free-standing walls at CSIRO.” Internal Rep. 86/47, Division of Building Research, Commonwealth Scientific and Industrial Research Organisation, Melbourne, Australia.
Kopp, G. A., Galsworthy, J. K., and Oh, J. H. (2010). “Horizontal wind loads on open-frame, low-rise buildings.” J. Struct. Eng., 98–105.
Letchford, C. W. (2001). “Wind loads on rectangular signboards and hoardings.” J. Wind Eng. Ind. Aerodyn., 89(2), 135–151.
Mara, T. G., Galsworthy, J. K., and Savory, E. (2010). “Assessment of vertical wind loads on lattice framework with application to thunderstorm winds.” Wind Struct., 13(5), 413–431.
National Research Council Canada (NRCC). (2010). National building code of Canada, Canadian Commission of Building and Fire Codes, Ottawa.
Pagon, W. W. (1958). “Wind forces on structures: Plate girders and trusses.” J. Struct. Div., 84(4), 1–27.
Standards Association of Australia (SAA). (2011). “Structural design actions—Wind actions.” AS/NZS 1170.2, North Sydney, NSW, Australia.
Swiss Society of Engineers and Architects (SIA). (1956). “Standards for load assumptions, acceptance and inspection of structures.” SIA Technische Normen No. 160, Zurich, Switzerland.
Whitbread, R. E. (1979). “The influence of shield on the wind forces experienced by arrays of lattice frames.” Proc., 5th Int. Conf. on Wind Engineering (IAWE), Pergamon Press, Oxford, U.K., 405–420.
Information & Authors
Information
Published In
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Nov 25, 2012
Accepted: Jun 5, 2013
Published online: Jun 7, 2013
Published in print: Mar 1, 2014
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.