Evaluation of fatigue category of riveted steel bridge connections: Fid-Bau Portal

Evaluation of fatigue category of riveted steel bridge connections

Matar, Ehab B.

Riveted bridges account for the majority of steel bridges that were built in different parts of the world before the middle of the last century. A large number of these bridges are still in service today. However, some of these bridges are more than 100 years old. Therefore, it is clear that while many existing bridges are structurally adequate with respect to the maximum design axle loads, they may suffer from fatigue related to the cyclic application of modern freight equipment axle loads. It should be noted that, generally, bridges designed within the past 40 years have considered fatigue effects, but that earlier bridge design did not include such considerations, even though, in some cases, the bridge may be found to be adequate for fatigue loads. A review of the different parameters affecting the fatigue strength of riveted connections shows that the effect of stress ratio, mean stress, bearing ratio, environmental conditions, rivet clamping forces and detail connection type are the most important ones. The available experimental results were sieved, based on certain criteria (stress ratio, stress level, connection detail and bearing ratio) to reduce the wide scatter of data which results in using the lower bound for the fatigue resistance of riveted connections. The suggested fatigue curves enhance the current practice of using just one fatigue class irrespective of detail types as the lower bound of experimental results by using fatigue category D (AASHTO) or fatigue category 71 (Eurocode).