American Society of Civil Engineers

Time-Domain Model for Predicting Aerodynamic Loads on a Slender Support Structure for Fatigue Design

by Byungik Chang, (corresponding author), (Assistant Professor, Dept. of Engineering and Computer Science, West Texas A&M Univ., Canyon, TX 79016), Partha Sarkar, M.ASCE, (Professor, Dept. of Aerospace Engineering, Iowa State Univ., Ames, IA 50011), and Brent Phares, M.ASCE, (Associate Director, Bridge Engineering Center, Iowa State Univ., Ames, IA 50010)

Journal of Engineering Mechanics, Vol. 136, No. 6, June 2010, pp. 736-746, (doi:

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Document type: Journal Paper
Abstract: This paper presents the development of a universal model for predicting cyclic aerodynamic loads originating from buffeting, self-excited, and vortex shedding on a slender support structure in the time domain that can be used to predict its fatigue life. To accomplish this development, long-term monitoring was performed on a high mast light pole (HMLP) and the field data were used to validate the developed mathematical model. Wind-tunnel tests were conducted on the dodecagonal (12-sided) cylindrical cross section of the light pole to obtain the necessary aerodynamic parameters such as static force coefficients, Strouhal number, and indicial functions for buffeting that appear in the postulated model. Furthermore, these aerodynamic parameters were cast into a coupled dynamic model for predicting the response of any HMLP in time domain from vortex shedding and buffeting.

ASCE Subject Headings:
Cyclic loads
Time factors

Author Keywords:
Vortex shedding
Time-domain model
Indicial function
Aerodynamic admittance function
Slender support structure
Light pole
Fatigue design