Many areas in Western Canada have experienced increasing heavy commercialvehicle loadings primarily related to resource based economic developmentover the past three decades. Combinations of changing moisture conditions, marginal granular materials, and heavy loadings often lead to prematureroad structure disintegration or catastrophic failure. In particular, areas with slow moving and turning truck traffic can significantly increase the applied stress states and moisture pumping effects within the road structure, both at the road surface and deep into the road structure. Structural strengthening of roads to sustain severe heavy truck loadings often requires the installation of substructure drainage systems prior to placement of the structural strengthening system. However, explicitly measuring the initial design requirements and the life cycle performance of substructure drainage systems in terms of active drainage as well as impact on structural integrity is difficult based on traditional empirical based road structural evaluation and design methods. This report summarizes the use of a mechanistic based structural asset management approach to evaluate the performance of existing substructure drainage systems and to engineer the requirements of new drainage systems for urban and rural roads by describing three case studies. Based on the findings of these case studies, the use of falling weight deflection and ground penetrating radar to provide mechanistic based structural assessment measurements are effective to quantify the spatial limits of drainage systems accurately, as well as assess theend product structural asset value added of drainage systems.
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