Historical load effects on fatigue of metallic railway bridges

This paper presents load models for quantifying the effect of historical rail traffic on the remaining fatigue life of riveted bridges in the UK. In this study, three types of load models, based on realistic trains, accounting for differences in rail traffic composition, were developed and subsequently used to investigate their effect on the accumulation of fatigue damage in typical old metallic bridge structures. The overall findings showed that the increase in train axle loads from 1900 to 2010 is the main attributor to the significant increase in fatigue damage caused from modern trains compared with the residual fatigue damage from historical trains. These findings are particularly relevant to the majority of existing metallic rail bridges on the rail network, which have a span length of less than 10 m. The findings show the importance of considering the effects of historical loading for more reliable fatigue assessment purposes, leading towards more efficient planning of bridge maintenance and renewal programmes.