The cumulative concept proposed by Palmgren and Miner [1] maintains that the damage level can be expressed in terms of the number of cycles applied at a given stress range divided by the number of cycles needed to produce failure for the same stress range. Failure occurs when the summation of these damage increments at several stress ranges becomes unity. After this formulation, this rule is repeatedly tested for different materials under multi-step and variable amplitude loading programs [2]. Though its applicability has been often questioned, it has been practically adopted by all design codes related to structural and mechanical fatigue design. In this paper, a fatigue damage assessment of a riveted connection made of puddle iron from the Fão bridge [3–6] using the modified probabilistic interpretation technique (MPIT) is applied [7]. This technique is a generalization of the Van Leeuwen and Siemes [8,9] work by considering a probabilistic S-N field providing a statistical distribution of the Miner number although based on a log-normal distribution. This generalization was proposed by Fernández-Canteli [10], based on the probabilistic model developed by Castillo and Fernández-Canteli [11].