Reliability calibration of load factors for the Australian rail traffic load model

Rail traffic loads in Australia are based on AS5100 Part 2, which stipulates a number of simulated axle groups, including a simulated locomotive, called the 300LA load model. The nominal axle loads and spacings are intended to replicate a heavy-haul rail line. As a result, for light rail, metro rail, and other forms of rail, the nominal axle loads are scaled, e.g. 150LA for light rail. However, the live load factor applied to these different load models remains 1.6 for all cases. It is hypothesized that the application of the same load factor to these different forms of rail live loading will result in inconsistent reliabilities being achieved by designs to AS5100. Therefore this paper examines the achieved reliabilities under current design practice for precast concrete bridges. From these results a revised set of load factors for the different forms of loading will be determined using reliability calibration. These load factors will ensure a more consistent reliability is achieved for designs using scaled versions of the 300LA load model. As such, this work should find use in the next revision of AS5100.