Use of Structural Asset Management to Evaluate Road Substructure Drainage Systems

Abstract

Over the past three decades, many areas in western Canada have experienced increasing volumes of heavy commercial vehicles, primarily related to resource-based economic development. Combinations of changing moisture conditions, marginal granular materials, and heavy loadings often lead to premature road structure distress, failure, or both. In particular, slow-moving and turning truck traffic can significantly increase the applied stress states and moisture-pumping effects within the road structure, both at the surface and deep within the road structure. Strengthening a road structure to sustain severe heavy truck loadings often requires installing substructure drainage systems before placing the structural strengthening system. However, explicitly measuring the initial design requirements and the life-cycle performance of substructure drainage systems, as well as the impact of drainage systems on structural integrity, is difficult with traditional empirical model–based road structural evaluation and design methods. The use of a mechanistic model–based structural asset management approach to evaluate the performance of existing substructure drainage systems and to engineer the requirements of new drainage systems across three case studies is summarized. The findings of these case studies indicate that falling weight deflectometer and ground-penetrating radar are effective mechanistic model–based methods of structural assessment. They accurately quantify the spatial limits, the end-product structural asset value, and the performance of in-service drainage systems.