In this study, through fatigue tests of specimens with outside or both side fillet welds joints between deck plate and trough ribs, the effect of inside fillet weld was investigated on fatigue durability of orthotropic steel deck with trough ribs by comparing the fatigue behaviour of outside fillet welded joints and both side fillet welded joints. As a result, in both side fillet welded joints, fatigue cracks were initiated at the toe and root of inside fillet welds, and propagated into the deck plate. The inside fillet welds had little effect on fatigue durability of fillet welded joint between deck plate and trough rib.
