Review of axle spacing mass schedules and future framework for assessment of heavy vehicle access applications

A key component to improving freight productivity in Australia is to improve access to the network for heavy vehicle operators. Assessment of bridge capacity is perceived to be critical to this aim. Currently bridge evaluation occurs using the performance based standards which only allow fast assessments up to the equivalent of the MS18 design load using the current bridge formulae. This project demonstrates the development of an assessment framework to allow fast assessment of bridges using a simple line model comparison approach. The process involves setting service levels that reflect the historic design levels adopted historically to design bridges. A reference vehicle can then be selected and calibrated to the service level. The results of the study show that the process is reasonable to assess the moment capacity of a bridge. There is more variability in the results related to the shear capacity which, for the majority of bridges in Australia will not be a significant issue however for shear critical structures the method should be used with caution. The study only related to simply supported bridges.