Flexible Pavement Strains Caused by Auto Tires

Abstract

This paper includes the results of an analytical study of the effects of automobile tire loads on thin asphalt pavements over granular bases. Two different methods of calculating the tire contact pressure are used and the strains induced in the pavement structure are evaluated. The uniform pressure tire model assumes that the tire contact pressure is equal to the tire inflation pressure. The Tielking tire model is a finite element computer program that models the tire as a shell of revolution and calculates the contact pressure distribution by using the tire carcass properties and the tire load. The contact pressure distributions are used in ILLIPAVE to calculate the strains at various locations in a pavement having a surface of thickness ranging from 2.54 to 10.16 cm (1 to 4 in.) and moduli ranging from 345 to 5,516 MPa (50 to 800 ksi). A granular base 20.32‐crn (8‐in.) thick with two different moduli is over a subgrade soil with a modulus of 34.5 MPa (5 ksi). The results are analyzed and the findings indicate that automobile tire loads can produce high pavement strains for certain combinations of surface thickness moduli over weak bases. The best performance occurs when stiff bases are used.