Design and Construction of a Full-Width, Full-Depth Precast Concrete Deck Slab on Steel Girder Bridge (05-0727)**
Alex Thomas Harrison, CH2M Hill
Norman David LeBlanc, Totten Sims Hubicki Associates

The existing West Sandusky Bridge over I-75, located in Findlay, Ohio, is being replaced with a new 170’ span hybrid steel plate girder bridge with concrete deck. In order to minimize closure times on West Sandusky Street, and reduce traffic delays on I-75 during construction, full-width, full-depth precast concrete deck panels will be used for the construction of the bridge deck. During preliminary design, a variety of alternate precast deck slab designs were considered, and a full-width, full-depth precast deck slab was selected as the preferred alternative. The precast deck panels are post-tensioned both longitudinally and transversely to minimize cracking and improve durability. The deck panels are constructed with shear stud pockets to allow for the installation of shear studs after erection and post-tensioning. During detail design, a finite element analysis of the bridge deck was carried out to determine the required level of prestressing in the deck. A time dependent analysis was subsequently carried out to determine the long term creep effects and post-tensioning losses, including the effects of restraint from the steel girders. A sensitivity analysis was carried out to determine the optimum curing time required prior to stressing the longitudinal post-tensioning tendons and grouting the shear pockets. The steel plate girders were designed for the additional long term creep effects due to the post-tensioning of the deck, which imposed additional axial loads and moments on the steel girders.