In recent years, many City of Saskatoon (COS) roads have experienced premature failures and pavement distresses. High water tables, increased precipitation, and poor surface drainage have led to more moisture infiltration within road structures. Further deterioration of these aged pavements is due to heavy loadings year round in urban traffic. Significant increases in commercial truck loadings across the Saskatchewan road network have resulted in accelerated damage to the provincial highway system, as well as urban roads. This paper quantifies the predicted strains and peak deflection in pavement structure layers due to different truck axle configurations. Single and tridem axle loads are examined across primary weight limits, on typical rural and urban cross sections. Typical rural and urban cross sections examined include dry and wet subgrades. Mechanistic primary response is predicted using a three dimensional non-linear orthotropic computational mechanics road model. Mechanistic analysis was used to model peak surface deflections and normal and shear strains within each pavement structure, for each load type and load spectra. The results of this research showed that a tridem axle load induced higher peak strains within the pavement structure, compared to a single axle load. Modeling results showed urban pavement structures constructed on a wet subgrade performed poorly and had strains and high peak surface deflections, especially with tandem axle loads. When a truck load is applied on the pavement edge, the model revealed a significant increase in shear strains at the edge of the “clay-box” (urban) or side slope edge (rural). Both areas are subject to lower confinement and are therefore more susceptible to strain failure, which materializes in the field as edge and side slope failures. Further analysis of the “clay-box” effect revealed significant shear strains within the subgrade due to effects at the edge of the urban road structure
