Stress charts for rigid pavements loaded by 16-wheel tandem axles

Stress charts are developed for the quick determination of maximum bending tensile stresses for the case of 16-wheel tandem axles (SWTA) on the interior of a concrete pavement slab on a Winkler foundation. The maximum bending moment in the concrete pavement represented by a Westergaard slab on Winkler foundation was obtained analytically by extending the known solution for the case of a uniformly loaded circular segment to the case of multiple circular contact areas. The effect on the maximum bending tensile stress of the modulus of subgrade reaction, modulus of elasticity of concrete, tyre pressure, SWTA load magnitude and SWTA geometry was studied thoroughly. The paper reveals that the effects on the maximum bending tensile stress of variation in the geometry of SWTAs and tyre pressure in Iraq are fairly insignificant, whereas the effects of SWTA load magnitude, relative axle spacing, modulus of subgrade reaction, modulus of elasticity of concrete and slab thickness are quite significant.