Assessing the Impacts of Proposed High-efficiency Log Truck Configurations on Ontario Pavements

Although Ontario has among the most generous and flexible commercial truck weight and dimension regulations, its truck-based industries must compete with those in other Canadian provinces that have instituted designated route or corridor-type transportation programs. Notably, British Columbia, Alberta, and Saskatchewan permit B-train trucks with 70.5-88.0 tonnes GCVW under these programs. FPInnovations, on behalf of Resolute Forest Products, is pursuing a similar opportunity in Ontario. Specifically, two 9-axle B-train configurations have been proposed for use in a log hauling corridor near Thunder Bay. If successful, the initiative will not only benefit the (northwest) Ontario forest industry through log hauling savings and improved competitiveness but also will reduce truck traffic, pavement maintenance, and GHG emissions.

In this study, the loading and dimensions of the proposed configurations were optimized to maximize payloads while ensuring safe vehicle dynamic performance, adequate bridge and culvert capacities, and acceptable pavement impacts. This paper emphasizes the  development of a novel and flexible methodology for assessing  the pavement impacts of the proposed 9 axle B train configurations .

The first step of this analysis was to compare the load equivalency of the proposed 9-axle B-train configurations with a baseline 8-axle B-train reference truck. To do so, the original Ontario Ministry of Transportation (MTO) terms of reference for pavement evaluations recommended the use of the relatively general AASHO method. To compliment and validate the results, the load equivalency analysis was repeated using TAC’s load equivalency factors (LEF) and widebase tire equivalency factors developed by FPInnovations. Preliminary results indicate that both of the proposed 9-axle B-train configurations generate less impact per tonne payload than the reference configuration. The second step of the pavement impact analysis consisted of conducting advanced pavement modeling to quantify instantaneous and long-term impacts to the pavements. This analysis compared impacts from the proposed trucks and from current log trucks and considered a range of representative King’s and Secondary Highway pavement structures, and ranges of material properties, that were identified through analyses of  MTO pavement data, FWD results, and other data sources.