Penetration depth of single-sided fillet weld between a trapezoidal rib and a deck plate in a steel plate deck is specified over 75% of the trapezoidal rib thickness in the Japanese Specifications for Design of Steel Highway Bridges in order to avoid fatigue problem. However, an effect of the weld penetration on the fatigue strength of single-sided fillet welded joint has not been made clear. In this study, the influence of the weld penetration depth on the fatigue strength is examined through fatigue tests, FEM stress analyses and fatigue crack propagation analyses.
