In this paper, effect of thickness of deck plate on fatigue durability of orthotropic steel deck is discussed with wheel running tests. Test specimen of this research has combinations of 16/19mm thickness deck plates and 6/8mm thickness U-shaped ribs. Wheel running tests with 4 million times loading were conducted on each part of the deck. Finite element analyses were also conducted in order to clarify effect of thickness of deck plate on local stress at weld joints connecting deck plate and U-shaped rib. It was clarified that local stresses at weld root become smaller and the crack propagation tends to slow with increase of deck plate.
