Bridges

The heavy vehicle industry and the structural engineering industry have a critical intersection when considering access applications for Restricted Access Vehicles (RAVs) over bridges. A large proportion of the bridge stock in Australia was designed for much smaller and lighter vehicles than those currently on the road network, and as such there is a significant mismatch between the design vehicle and the application vehicle.

At the same time, there has been innovation in the heavy vehicle industry leading to ever more combinations of axle mass and spacing. The proliferation of innovative vehicles, particularly under the PBS (Performance Based Standards) scheme, has led to a considerable challenge for local authority road managers trying to understand if every combination of prime movers and trailers listed on a permit application is within the capability of the bridges on their road network.

It is evident that there is a need for greater understanding from both structural engineers and the heavy vehicle industry of the capabilities and limitations of each other’s industries, and a need for structural engineers to give practical and useful advice when undertaking bridge assessments for heavy vehicle access.

This paper discusses some of the most common heavy vehicle types accessing the road network, the relationship between these vehicles and bridge capability, some of the mitigation measures and conditions that can be employed to bring vehicles within the capability of specific bridges, and some of the short- and medium-term solutions to these challenges.