Aerodynamics of Highway Sign Structures: From Laboratory Tests and Field Monitoring to Structural Design Guidelines
Publication: Journal of Structural Engineering
Volume 146, Issue 11
Abstract
Field- and model-scale experiments were conducted to quantitatively assess the effects of wind loading on Rural Intersection Conflict Warning System (RICWS) highway sign structures. A field-scale RICWS was instrumented with acceleration and linear displacement sensors to monitor unsteady loads, dynamics, and displacement of the sign under various wind events classified by cup and vane wind velocity measurements. To complement the field-scale results, tests on a -scale model were conducted under controlled laboratory conditions in the St. Anthony Falls Laboratory towing tank and wind tunnel facilities. Aerodynamic effects on the sign structure were identified through analysis of the mean and oscillating drag and lift forces. Vortices periodically shed by the structure induced forces at a frequency governed by the Strouhal number. The shedding frequency overlapped with the estimated natural frequency during strong wind events, leading to possible resonance. Amplified oscillations were additionally observed when the wind direction was parallel to the structure, possibly due to an aeroelastic instability. The findings highlight the relevance of aerodynamic effects on roadside signs or similar complex planar geometries under unsteady wind loading.
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Data Availability Statement
Data and code generated or used during the study are available from the corresponding author by request.
References
AASHTO. 2017. LRFD specifications for structural supports for highway signs, luminaries, and traffic signals. Washington, DC: AASHTO.
Amy, R. A., G. S. Aglietti, and G. Richardson. 2009. “Reliability analysis of electronic equipment subjected to shock and vibration—A review.” Shock Vib. 16 (1): 45–59. https://doi.org/10.1155/2009/546053.
Berger, E., and R. Wille. 1972. “Periodic flow phenomena.” Annu. Rev. Fluid Mech. 4 (1): 313–340. https://doi.org/10.1146/annurev.fl.04.010172.001525.
Bokaian, A., and F. Geoola. 1984. “Vortex shedding from two interfering circular cylinders.” J. Eng. Mech. 110 (4): 623–628. https://doi.org/10.1061/(ASCE)0733-9399(1984)110:4(623).
Chamorro, L. P., and F. Porté Agel. 2009. “A wind-tunnel investigation of wind-turbine wakes: Boundary-layer turbulence effects.” Boundary Layer Meteorol. 132 (1): 129–149. https://doi.org/10.1007/s10546-009-9380-8.
Chang, B., B. M. Phares, P. P. Sarkar, and T. J. Wipf. 2009. “Development of a procedure for fatigue design of slender support structures subjected to wind-induced vibration.” Transp. Res. Rec. 2131 (1): 23–33. https://doi.org/10.3141/2131-03.
Chen, Z. Q., X. D. Yu, G. Yang, and B. F. Spencer. 2005. “Wind-induced self-excited loads on bridges.” J. Struct. Eng. 131 (12): 1783–1793. https://doi.org/10.1061/(ASCE)0733-9445(2005)131:12(1783).
Christenson, R. E., and S. Hoque. 2011. “Reducing fatigue in wind-excited support structures of traffic signals with innovative vibration absorber.” Transp. Res. Rec. 2251 (1): 16–23. https://doi.org/10.3141/2251-02.
Connor, R. J., S. H. Collicott, A. M. DeSchepper, R. J. Sherman, and J. A. Ocampo. 2012. Fatigue loading and design methodology for high-mast lighting towers. Washington, DC: Transportation Research Board.
Draxl, C., A. Clifton, B. M. Hodge, and J. McCaa. 2015. “The wind integration national dataset (WIND) toolkit.” Appl. Energy 151 (Aug): 355–366. https://doi.org/10.1016/j.apenergy.2015.03.121.
Garlich, M. J., and E. T. Thorkildsen. 2005. Guidelines for the installation, inspection, maintenance and repair of structural supports for highway signs, luminaries, and traffic signals. Washington, DC: Federal Highway Administration.
Giaralis, A., and F. Petrini. 2017. “Wind-induced vibration mitigation in tall buildings using the tuned mass-damper-inerter.” J. Struct. Eng. 143 (9): 04017127. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001863.
Heisel, M., J. Hong, and M. Guala. 2018. “The spectral signature of wind turbine wake meandering: A wind tunnel and field-scale study.” Wind Energy 21 (9): 715–731. https://doi.org/10.1002/we.2189.
Hong, H. P., G. G. Zu, and J. P. C. King. 2014. “Reliability consideration for fatigue design of sign, luminaries, and traffic signal support structures under wind load.” J. Wind Eng. Ind. Aerodyn. 126 (Mar): 60–74. https://doi.org/10.1016/j.jweia.2013.12.012.
Hosch, I. E., and F. H. Fouad. 2009. “Fatigue design of sign support structures for loading caused by natural wind loads.” Transp. Res. Rec. 2131 (1): 15–22. https://doi.org/10.3141/2131-02.
Howard, K. B., J. S. Hu, L. P. Chamorro, and M. Guala. 2015. “Characterizing the response of a wind turbine model under complex inflow conditions.” Wind Energy 18 (4): 729–743. https://doi.org/10.1002/we.1724.
Kareem, A., L. Hu, Y. Guo, and D. K. Kwon. 2019. “Generalized wind loading chain: Time-frequency modeling framework for nonstationary wind effects on structures.” J. Struct. Eng. 145 (10): 04019092. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002376.
Kareem, A., and T. Wu. 2013. “Wind-induced effects on bluff bodies in turbulent flows: Nonstationary, non-Gaussian and nonlinear features.” J. Wind Eng. Ind. Aerodyn. 122 (Nov): 21–37. https://doi.org/10.1016/j.jweia.2013.06.002.
Knisely, C. W. 1990. “Strouhal numbers of rectangular cylinders at incidence: A review and new data.” J. Fluids Struct. 4 (4): 371–393. https://doi.org/10.1016/0889-9746(90)90137-T.
Lam, K. M., and C. T. Wei. 2010. “Numerical simulation of vortex shedding from an inclined flat plane.” Eng. Appl. Comp. Fluid Mech. 4 (4): 569–579. https://doi.org/10.1080/19942060.2010.11015342.
Levi, E. 1983. “A universal Strouhal law.” J. Eng. Mech. 109 (3): 718–727. https://doi.org/10.1061/(ASCE)0733-9399(1983)109:3(718).
Lienhard, J. H. 1966. Synopsis of lift, drag, and vortex frequency data for rigid circular cylinders. Pullman, WA: Washington State Univ.
McGregor, D. M. 1957. An experimental investigation of the oscillating pressures on a circular cylinder in a fluid stream. North York, ON, Canada: Univ. of Toronto Institute for Aerospace Studies.
MnDOT (Minnesota DOT). 2014. “Concept of operations prepared for Minnesota department of transportation (MnDOT) for rural intersection conflict warning systems II deployment.” Accessed August 23, 2018. https://www.dot.state.mn.us/its/projects/2011-2015/rural-intersect-conflict-warn-system/documents/ricwsIIconops.pdf.
MnDOT (Minnesota DOT). 2015. “Traffic engineering: Rural intersection conflict warning system (RICWS).” Accessed December 1, 2018. http://www.dot.state.mn.us/trafficeng/signals/conflictwarning.html.
MnDOT (Minnesota DOT). 2016. Improved structural design for rural intersection conflict warning signs (RICWS). St. Paul, MN: MnDOT.
Munson, B. R., A. P. Rothmayer, T. H. Okiishi, and W. W. Huebsch. 2012. Fundamentals of fluid mechanics, 7th ed. Hoboken, NJ: Wiley.
Musa, M., C. Hill, F. Sotiropoulos, and M. Guala. 2018. “Performance and resilience of hydrokinetic turbine arrays under large migrating fluvial bed forms.” Nat. Energy 3 (10): 839–846. https://doi.org/10.1038/s41560-018-0218-9.
Norberg, C. 2001. “Flow around a circular cylinder: Aspects of fluctuating lift.” J. Fluids Struct. 15 (3–4): 459–469. https://doi.org/10.1006/jfls.2000.0367.
Ortiz, X., D. Rival, and D. Wood. 2015. “Forces and moments on flat plates of small aspect ratio with application to PV wind loads and small wind turbine blades.” Energies 8 (4): 2438–2453. https://doi.org/10.3390/en8042438.
Rai, M. M. 2013. “Flow physics in the turbulent near wake of a flat plane.” J. Fluid Mech. 724 (Jun): 704–733. https://doi.org/10.1017/jfm.2013.185.
Raupach, M. R., R. A. Antonia, and S. Rajagopalan. 1991. “Rough-wall turbulent boundary layers.” Appl. Mech. Rev. 44 (1): 1–25. https://doi.org/10.1115/1.3119492.
Roshko, A. 1954. On the development of turbulent wakes from vortex streets. Cleveland: National Advisory Committee for Aeronautics.
Sherman, R. J., and R. J. Connor. 2019. “Development of a fatigue design load for high-mast lighting towers.” J. Struct. Eng. 145 (1): 04018228. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002236.
Simiu, E., and D. H. Yeo. 2019. Wind effects on structures: Modern structural design for wind. 4th ed. Hoboken, NJ: Wiley.
Solari, G. 2017. “Gust buffeting of slender structures and structural elements: Simplified formulas for design calculations and code provisions.” J. Struct. Eng. 144 (2): 04017185. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001949.
Sun, Y., Y. Wu, Y. Qiu, and Y. Tamura. 2014. “Effects of free-stream turbulence and Reynolds number on the aerodynamic characteristics of a semi cylindrical roof.” J. Struct. Eng. 141 (9): 04014230. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001209.
Surry, D. 1972. “Some effects of intense turbulence on the aerodynamics of a circular cylinder at subcritical Reynolds number.” J. Fluid Mech. 52 (3): 543–563. https://doi.org/10.1017/S0022112072001582.
Welch, P. D. 1967. “The use of fast Fourier transform for the estimation of power spectra: A method based on time averaging over short, modified period grams.” IEEE Trans. Audio Electroacoust. 15 (2): 70–73. https://doi.org/10.1109/TAU.1967.1161901.
Williamson, C. H. K., and R. Govardhan. 2004. “Vortex-induced vibrations.” Annu. Rev. Fluid Mech. 36 (Jan): 413–455. https://doi.org/10.1146/annurev.fluid.36.050802.122128.
Wu, T., and A. Kareem. 2013. “Vortex-induced vibration of bridge decks: Volterra series-based model.” J. Eng. Mech. 139 (12): 1831–1843. https://doi.org/10.1061/(ASCE)EM.1943-7889.0000628.
Yang, D., B. Pettersen, H. I. Andersson, and V. D. Narasimhamurthy. 2012. “Vortex shedding in flow past an inclined flat plate at high incidence.” Phys. Fluids 24 (8): 084103. https://doi.org/10.1063/1.4744982.
Zhu, Q., S. K. F. Stoter, M. Heisel, C. E. French, M. Guala, L. E. Linderman, and D. Schillinger. 2020. “Reducing wind-induced vibrations of road sign structures through aerodynamic modifications: A computational pilot study for a practical example.” J. Wind Eng. Ind. Aerodyn. 199 (Apr): 104132. https://doi.org/10.1016/j.jweia.2020.104132.
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Published In
Journal of Structural Engineering
Volume 146 • Issue 11 • November 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Aug 20, 2019
Accepted: May 22, 2020
Published online: Aug 20, 2020
Published in print: Nov 1, 2020
Discussion open until: Jan 20, 2021
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