Residual Lifetime Assessment of an Ancient Riveted Steel Road Bridge

: The present paper reports research work carried out to characterise the fatigue behaviour of the Portuguese Pinhão riveted road bridge, built in 1903 over the Douro river. The present traffic conditions are completely different from those foreseen by the bridge designer, rising new concerns, with respect to the bridge integrity, namely its fatigue behaviour. An experimental programme was performed using original material removed from the bridge. The chemical composition and microstructures of the removed materials were characterised. Also, the notch toughness, at room temperature, was evaluated using both notch impact and Crack Opening Displacement (COD) tests. Fatigue crack growth tests were also used to evaluate the fatigue crack growth behaviour. Finally, fatigue tests of riveted joints were conducted in order to define an appropriate S‐N curve. The experimental results were used to evaluate the residual fatigue strength of the bridge, adopting both S‐N and Fracture Mechanics approaches. The analysis revealed a good tolerance to fatigue cracking, even in the presence of small fatigue cracks, detected in the joints.