Substantial benefits can be realized by forest companies in British Columbia through implementation of new 9-axle log-hauling configurations. At the request of the British Columbia Ministry of Forests, Lands and Natural Resource Operations, FPInnovations undertook analyses to assess the potential impacts of the new trucks on resource roads and bridges. The analyses considered forestry bridge capacity (up to 36 m spans), vehicle fit to the resource road, gradeability, and road impacts. The vehicle weights and dimensions authorized for designated provincial highways were the basis for the analyses.
Those planning to implement 9-axle configurations on B.C. resource roads are advised to review the capacity of the infrastructure on their networks in light of the findings of this analysis. Bridges with less capacity than L-75 bridges were found to have length restrictions (that is, 9-axle B-trains generated force effects in excess of the bridge design vehicle for spans of 36 m or less). The capacity of L-45, L-60, CL-625, and BCL-625 bridges that exceed the maximum lengths identified in this report should be independently evaluated and certified by a professional bridge engineer for use with the 9-axle B-trains. Concrete beam bridges, designed according to pre-2000 design codes, may be under-designed for shear. This report’s general analysis must not be applied to pre-2000 concrete beam bridges of over 18.5 m span and, instead, a consulting bridge engineer should be engaged to determine their shear capacity.