ABSTRACT
ABSTRACT: A large percentage of the railway bridges in the UK rail network and around Europe are of riveted construction exceeding in many cases 100 years of age. The remaining fatigue life of these bridges is difficult to estimate due to the uncertainties regarding the fatigue behaviour of wrought-iron and older steel material which were used for their construction. The problem is further compounded by the uncertainties associated with the loading both past and future. Previous global finite element analyses of a typical wrought-iron riveted railway bridge have shown that the fatigue critical details are the inner stringer-to-cross-girder connections (Imam et al. 2005). The analyses were carried out under a historical load model (Imam et al. 2005), developed to represent rail traffic in the period 1900-1970, and present day traffic (BS5400 1980) for the period 1970 onwards. Deterministic remaining fatigue life estimates of the connections were found to be sensitive to the level of dynamic amplification as well as the fatigue classification of the details. Following this work, this paper presents probabilistic fatigue life estimates for the most highly damaged stringer-to-cross-girder connection, as identified by the global analysis of the riveted bridge. On the loading side, the problem is randomised through the frequency of train traffic, dynamic amplification and uncertainties regarding the difference between actual and calculated stresses. On the response side, different assumed S-N curves used for detail classification and the Miner sum are also treated as random.
