Truck‐Tire Steel Grid Deck Contact Pressure Distributions

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, rather than parallel to the traffic flow.