Minimum Thickness of RC Deck Slab for a Composite Two-Girder Bridge Considering Serviceability and Constructability

Minimizing thickness of long-span deck slab is one of the key factors for the practical and economic design of a composite two-girder bridge. Korean Bridge Design Code (KBDC) updated in 2005 also adapted new requirements for the minimum thickness of the long-span deck slab. But because specific value of minimum thickness based on the slab span length is not available directly, it is very difficult for designers to decide proper minimum thickness. In this paper, the minimum thickness of RC long-span deck slab for a composite two-girder bridge is proposed as a function of slab span length, which satisfies KBDC's constructability and serviceability such as fatigue, crack width, and deflection requirements. In addition, KBDC's distribution rebar requirement for the long-span deck slab is examined. The proposed minimum thickness turns out to be thinner than one given by ordinary RC deck slab's minimum thickness function. Also, for the RC deck slab with span length longer than 4m, additional reinforcement is needed to meet required ultimate strength of distribution rebar section that satisfies KBDC's distribution rebar requirement