Fatigue of Reinforced Concrete Railway Trough Bridges in Northern Sweden - Structural Safety and Reliability

With increasing traffic volumes on Malmbanan (the Ore Line) between the ore fields in Northern Sweden and the harbors in Luleå and Narvik, there is a need to raise the axle load allowed on the track, This, in turn, necessitates the analysis and if needed, enhancement of the capacity of the railway bridges. To facilitate this, fatigue tests are being conducted on a full-scale model of a reinforced concrete trough bridge. Calculations of the load effects from dead weight and axle loads are performed using the Eurocodes and the fib Model Codes (2010 and 2020). The results indicate that the axle load on the Ore line can be increased to 35 tons without the risk of bending or shear fatigue failure in the trough bridges. However, the fatigue capacity varies considerably, both between different bridges and across different codes, so continued Structural Health Monitoring is recommended.