Analysis of Concrete Pavements by Rectangular Thick-Plate Model

Abstract

Westergaard solutions for maximum bending stress and deflection are derived by assuming infinite slab width and length, and ignoring possible thick-plate behavior of slab under loading. This paper examines the effects of these two factors on Westergaard solutions by comparing with thick-plate solutions for rectangular slabs derived by the writers. The infinite slab assumption is found valid if the slab length is more than four times the radius of relative stiffness. However, because of thick-plate action, not all solutions for slab responses converge to Westergaard values when slab sizes are large. For large slabs where the effect of slab dimensions is negligible, the difference of thick-plate solutions and Westergaard solutions for maximum bending stress are less than 15% for square slabs, and less than 20% for 3.66 m (12 ft) wide rectangular slabs. For these large slabs, the values of maximum deflection obtained from the two solutions show good agreement in the case of square slabs. However, for 3.66 m wide rectangular slabs, Westergaard solutions underestimate maximum deflection by 10–70%, depending on the value of radius of relative stiffness of the slab-on-grade system.