American Society of Civil Engineers

Truck-Tire Steel Grid Deck Contact Pressure Distributions

by Hota V. S. GangaRao, (Prof. and Dir., Constr. Facilities Ctr., Civ. Engrg. Dept., P.O. Box 6101, West Virginia Univ., Morgantown, WV 26506-6101) and Arshad Vali, (Struct. Engr., Rust Int. Corp., Pittsburgh, PA 15222)

Journal of Structural Engineering, Vol. 116, No. 3, March 1990, pp. 791-808, (doi:

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Document type: Journal Paper
Abstract: This study deals with the mathematical and experimental determination of contact pressure distribution between bridge decks and truck tires. The variables associated with this study are tire inflation pressure, axle loads, treaded or bald tire, and main bar spacing and its orientation with traffic flow. A classical structural mechanics approach for contact pressure distribution has been developed by idealizing the open steel grid deck and the tire as two different springs in series. In addition, an approximate, but simplified, distribution procedure has been developed. Synthesis of our test data reveals the following trends: (1) Increase in inflation pressure increases the peak values of the contact pressure distribution profile; (2) maximum contact pressure is found to be about 2.5 times the average pressure computed from the current AASHTO specifications for highway bridges; (3) rate of increase in contact pressure is not as rapid as the increase in axle loads; (4) fully treaded tires are found to result in higher contact pressures than the bald tires; and (5) load carried by main bars is higher when they are placed perpendicular to, more than parallel to the traffic flow.

ASCE Subject Headings:
Bridge decks
Contact pressure
Grid systems
Highway bridges
Load distribution
Pressure distribution