Chapter 7
Longitudinal Forces on Transmission Towers due to Non-Symmetric Downburst Ground Wire Loads
Publication: Wind Engineering for Natural Hazards: Modeling, Simulation, and Mitigation of Windstorm Impact on Critical Infrastructure
Abstract
Downburst thunderstorms are localized high-intensity wind events that are formed by an intensive downdraft of cold air that impinges on the ground causing high radial wind speeds. Spatial localization of downbursts causes unique oblique load cases on long-span structures such as transmission lines that do not occur during synoptic winds. This loading scenario causes an unsymmetrical wind loading along the spans of the cables, resulting in an unbalanced longitudinal force acting on the transmission tower of interest. This longitudinal force is highly nonlinear; it depends on the material and geometrical properties of the cables. Therefore, a nonlinear analysis should be conducted considering the various possibilities of downburst-cable configurations and the cable material and geometrical properties. This paper focuses on developing a simplified and manual approach to estimate this damaging longitudinal force, which develops in ground wires of transmission lines.
Get full access to this article
View all available purchase options and get full access to this chapter.
References
Aboshoshaa, H., and A. El Damatty. 2014. “Effective technique to analyze transmission line conductors under high intensity winds.” Wind Struct.18 (3): 235-252.
Aboshosha, H., and A. El Damatty. 2015. “Engineering method for estimating the reactions of transmission line conductors under downburst winds.” J Eng Struct.142: 198-216.
ASCE. 2010. Guidelines for electrical transmission line structural loading. New York: ASCE.
Australian Wind Alliance. 2016. http://www.windalliance.org.au/.
Darwish, M. M., and A. A. El Damatty. 2011. “Behavior of self supported transmission line towers under stationary downburst loading.” Wind Struct.14 (5): 481-498.
Darwish, M. M., A. A. El Damatty, and H. Hangan. 2010. “Dynamic characteristics of transmission line conductors and behaviour under turbulent downburst loading.” Wind Struct.13 (4): 327-346.
Elawady, A.2016. “Development of design loads for transmission line structures subjected to downbursts using aero-elastic testing and numerical modeling.” Ph.D. thesis Univ. of Western Ontario.
Elawady, A., H. Aboshosha, A. El Damatty, G. Bitsuamlak, H. Hangan, and A. Elatar. 2017. “Aero-elastic testing of multi-spanned transmission line subjected to downbursts.” J. Wind Eng. Ind. Aerodyn.169: 194-216.
Elawady, A., and A. El Damatty. 2016. “Longitudinal force on transmission towers due to non-symmetric downburst conductor load.” J. Eng. Struct.127: 206-226.
Fujita, T.T.1985. The downburst: Microburst and macroburst: SMRP Research Paper 210. Chicago: Univ. of Chicago.
Gattulli, V., L. Martinelli, F. Perotti, and F. Vestroni. 2007. “Dynamics of suspended cables under turbulence loading: reduced models of wind field and mechanical system.” J. Wind Eng. Ind. Aerodyn.95 (3): 183-207.
Holmes, J. D., H. M. Hangan, J. L. Schroeder, C. W. Letchford, and K. D. Orwig. 2008. “A forensic study of the Lubbock-Reese downdraft of 2002.” Wind Struct.11 (2): 137-152.
Kim, J., and H. Hangan. 2007. “Numerical simulations of impinging jets with application to downbursts.” J. Wind Eng. Ind. Aerodyn.95 (4): 279-298.
Loredo-Souza, A. M., and A. G. Davenport. 1998. “The effects of high winds on transmission lines.” J. Wind Eng. Ind. Aerodyn.74: 987-994.
Mara, T., and H. Hong. 2013. “Effect of wind direction on the response and capacity surface of a transmission tower.” Eng. Struct.57: 493-501.
McCarthy, P., and M. Melsness. 1996. Severe weather elements associated with September 5, 1996 hydro tower failures near Grosse. Manitoba Environmental Service Centre.
Shehata, A. Y., and A. A. El Damatty. 2007. “Behaviour of guyed transmission line structures under downburst wind loading.” Wind Struct.10 (3): 249-268.
Shehata, A. Y., and A. A. El Damatty. 2008. “Failure analysis of a transmission tower during a microburst.” Wind Struct.11 (3): 193-208.
Shehata, A. Y., A. A. El Damatty, and E. Savory. 2005. “Finite element modeling of transmission line under downburst wind loading.” Finite Elem. Anal. Des.42 (1): 71-89.
The White House. 2013. “Economic benefits of increasing electric grid resilience to weather outages.” Executive Office of the President, Washington. http://energy.gov/sites/prod/files/2013/08/f2/Grid%20Resiliency%20Report_FINAL.pdf.
Wang, X., W. Lou, H. Li, and Y. Chen. 2009. “Wind-induced dynamic response of high-rise transmission tower under downburst wind load.” J. Zhejiang Univ.43 (8): 1520-1525.
Yang, F., and H. Zhang. 2016. “Two case studies on structural analysis of transmission towers under downburst.” Wind Struct.22 (6): 685-701.
Zhang, Y.2006. “Status quo of wind hazard prevention for transmission lines and counter measures.” East China Electric Power34 (3): 28-31.
Information & Authors
Information
Published In
Wind Engineering for Natural Hazards: Modeling, Simulation, and Mitigation of Windstorm Impact on Critical Infrastructure
Pages: 133 - 147
Copyright
© 2018 American Society of Civil Engineers.
History
Published online: Oct 3, 2018
ASCE Technical Topics:
- Asymmetry
- Cables
- Continuum mechanics
- Design (by type)
- Dynamic loads
- Dynamics (solid mechanics)
- Electric power
- Energy engineering
- Energy infrastructure
- Engineering fundamentals
- Engineering mechanics
- Equipment and machinery
- Infrastructure
- Lifeline systems
- Load factors
- Longitudinal loads
- Material mechanics
- Material properties
- Materials engineering
- Mathematics
- Power transmission
- Power transmission towers
- Solid mechanics
- Static loads
- Statics (mechanics)
- Structural design
- Structural dynamics
- Symmetry
- Wind loads
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.