The Fatigue Behaviour of the Breathing Webs of Steel Bridge Girders

Abstract

The limit state of thin‐walled steel girders subjected to many times repeated loading is to a great extent affected by the cumulative damage process occurring in the girder webs “breathing” under the repeated loads. Based on experimental results obtained by the authors at the Institute of Theoretical and Applied Mechanics in Prague, (i) various approaches to the definition of the fatigue limit state of the above girders are discussed, (ii) a number of potential design procedures suggested by other researchers validated and (iii) a set of S‐N curves, established by the writers so as to serve as a reliable tool for the fatigue analysis of thin‐walled girders with “breathing” webs, presented.

The fatigue behaviour of the breathing webs of steel bridge girders

“…The above research was during its first stage supported by a fruitful co-operation with Cardiff School of Engineering, where another twenty breathing tests were carried out several years ago. The results of the collaborative Prague and Cardiff research were published in a number of papers (see, for example, Ðkaloud, & Zörnerová [1] and Ðkaloud & Roberts [2]).…”

FRP strengthening of web panels of steel plate girders against shear buckling. Part-II: Fatigue study and cyclic series of tests

“…They also demonstrated that the fatigue assessment procedures recommended in the Eurocodes, based on either principal stress ranges or normal and shear stress ranges, provided conservative estimates of the fatigue life for slender webs subjected to web plate breathing under cyclic shear loading. Skaloud and Zornerova (2005) also studied the fatigue response of slender plates in shear. They studied the limit state for the webs of steel plate girders subjected to repeated loading, and noted, unsurprisingly, that the response is affected by the cumulative damage process generated in the web under repeated loading.…”

Probabilistic fatigue life analysis of welded steel plate railway bridge girders using S–N curve approach

“…at the web-to-flange and web-to-transverse stiffener junctions, which generates a pronounced cumulative (fatigue) damage in the girder. 2 Skaloud and Zornerova 2 carried out experimental investigations on fatigue behavior of steel plate girders, and reported that the main impact of the cumulative damage process induced by plate breathing was the initiation and propagation of fatigue cracks, which almost always develop at the toes of the fillet welds connecting the 'breathing' web with the girder flanges and stiffeners (see Figures 1 and 2). This indicates that, within the context of ultimate limit state design philosophy, plate breathing is an important failure mechanism to be considered while assessing the fatigue life of plate girder bridges with welded connections.…”