Wind and Structures

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Practical fatigue/cost assessment of steel overhead sign support structures subjected to wind load

  • van de Lindt, John W. (Department of Civil Engineering, Colorado State University) ;
  • Ahlborn, Theresa M. (Civil and Environmental Engineering, Michigan Technological University)
  • Received : 2004.04.01
  • Accepted : 2005.07.06
  • Published : 2005.10.25
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Abstract

Overhead sign support structures number in the tens of thousands throughout the trunk-line roadways in the United States. A recent two-phase study sponsored by the National Cooperative Highway Research Program resulted in the most significant changes to the AASHTO design specifications for sign support structures to date. The driving factor for these substantial changes was fatigue related cracks and some recent failures. This paper presents the method and results of a subsequent study sponsored by the Michigan Department of Transportation (MDOT) to develop a relative performance-based procedure to rank overhead sign support structures around the United States based on a linear combination of their expected fatigue life and an approximate measure of cost. This was accomplished by coupling a random vibrations approach with six degree-of-freedom linear dynamic models for fatigue life estimation. Approximate cost was modeled as the product of the steel weight and a constructability factor. An objective function was developed and used to rank selected steel sign support structures from around the country with the goal of maximizing the objective function. Although a purely relative approach, the ranking procedure was found to be efficient and provided the decision support necessary to MDOT.

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References

  1. AASHTO (2001), With interims, Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals, Fourth Edition, American Association of State Highway and Transportation Officials, Washington D.C.
  2. Ahlborn, T.M., van de Lindt, J.W. and Lewis, M.E. (2003), Optimization of Cost and Performance of Overhead Sign Support Structures, Report JN-56886, Michigan DOT, October 2003.
  3. ASCE 7 (1998), American Society of Civil Engineers, Minimum Design Loads for Buildings and Other Structures, ASCE 7-98, Reston, VA, 330pp.
  4. Benjamin, J.R. and Cornell, C.A. (1970), Probability, Statistics, and Decision for Civil Engineers, McGraw Hill, New York, NY.
  5. Clough, R.W. and Penzien, J. (1993), Dynamics of Structures, McGraw-Hill, Inc., New York, New York.
  6. Cook, R.D., Malkus, D.S., Plesha, M.E. and Witt, R.J. (2002), Concept and Applications of Finite Element Analysis. John Wily and Sons Inc, Madison, WI.
  7. Crandall, S.H. and Mark, W.D. (1963), Random Vibration in Mechanical Systems, Academic Press, New York and London.
  8. Dexter, R.J. and Ricker, M.J. (2002), NCHRP Report 469: Fatigue-Resistant Design of Cantilever Signal, Sign, and Light Supports. TRB, National Research Council, Washington D.C.
  9. Groisman, P.Y. and Barker, H.P. (2002), "Homogeneous blended wind data over the contiguous United States", Proc. of the 13th AMS Conference on Applied Climatology, Portland, OR, 13-16 May, 2002, Amer. Meteorol. Soc., Boston, Mass.
  10. Holmes, J.D. (2002), "Fatigue life under along-wind loading - closed form solutions", Eng. Struct., 24, 109-114. https://doi.org/10.1016/S0141-0296(01)00073-6
  11. Kaczinski, M.R., Dexter, R.J. and van Dien, J.P. (1998), NCHRP Report 412: Fatigue-Reistance Design of Cantilevered Signal, Sign, and Light Supports, TRB, National Research Council, Washington D.C.
  12. MDOT (2001), Sign Support Typical Plans. Michigan Department of Transportation, Michigan.
  13. Miner, M.A. (1945), "Cumulative damage in fatigue", J. Applied Mechanics, 12, A159-A164.
  14. Palmgren, A. (1924), Die Lebensdauer von Kugellagern, Ver. Deut. Ingr., 68, 339-341, (In German).
  15. Robertson, A.P., Holmes, J.D. and Smith, B.W. (2003), "Calibrations of closed-form solutions of fatigue life under along-wind loading", 11th International Conference on Wind Engineering, Lubbock TX, June 2-5, 1787-1793.
  16. Robertson, A.P., Hoxey, R.P., Short, J.L., Burgess, L.R., Smith, B.W. and Ko, R.H.Y. (2001), "Wind induced fatigue loading of tubular street lighting columns", Wind and Struct., 4, 163-176. https://doi.org/10.12989/was.2001.4.2.163

Cited by

  1. Fatigue analysis of overhead sign support structures vol.32, pp.6, 2010, https://doi.org/10.1016/j.engstruct.2010.02.014