Fatigue Life Estimation of Rib-to-Deck Joints in Orthotropic Steel Decks

A typical rib-to-deck joint in orthotropic steel bridge deck in a suspension bridge is analyzed in this paper. A local finite element model of bridge deck is established by ANSYS, the vehicle load defined in current code is selected as live load, the stress distribution of the deck bottom in the rib-to-deck joint is analyzed. Let the wheel load move along the longitudinal direction of the deck, the maximum stress range at rib-to-deck joint is obtained under three loading conditions in transverse direction, which are riding-rib wall loading, over-rib loading, and in-between-ribs loading respectively. Using the principles of linear elastic fracture mechanics, the fatigue life of rib-to-deck joint in orthotropic steel decks is evaluated. The analysis results indicate that, the higher stress range under overweight wheel load is the basic reason which will induce fatigue crack at rib-to-deck joint. The Paris formula which is based on the linear elastic fracture mechanics can be used to estimate the residual life of weld joints in orthotropic steel bridge deck.