Fatigue Performance of Orthotropic Steel Bridge Decks with Inner Diaphragm in U rib

Abstract:

Fatigue performance of orthotropic steel decks with U rib was investigated based on the specific constructional detailing of the steel railway decks. Two full scale specimens, DECK1 which had the inner diaphragms in the U ribs, and DECK2 which did not have the inner diaphragms were tested under the static loading and the high cycled loading. Test results show that inner diaphragms in the U ribs help to redistribute stress in web of the rib and stress in diaphragm of the crossbeam, and hence to improve the fatigue strength of rib to diaphragm detail in the orthotropic steel railway decks. Fatigue cracks initiates very likely from the toe of the rib to diaphragm welds, and both specimens develop horizontal cracks in the web of rib at the position close to the rib to diaphragm connections. Finite element (FE) model of the decks is developed and the results agree well with the test results. Influences of the inner diaphragms in the U ribs on the stress state and the fatigue performance of the deck were analyzed.