This paper presents a debonded shear key system for prestressed concrete bridge girders with composite cast-in-place decks. The system utilizes the mechanical anchorage of concrete shear keys created on the top flange of a concrete girder, combined with shear reinforcement crossing the interface. The system has the advantage of facilitating future deck removal, while protecting the top flange of the girder from damage, which is particularly significant for bridges in cold climates where deck concrete is subjected to deterioration due to freeze-thaw cycles and deicing chemicals. Theoretical background, experimental results, production issues, design criteria and construction specifications of this system are discussed. Details of the first bridge project using this system in Nebraska are also given. Lastly, a numerical design example is provided to show the required calculations for the proposed shear key system in composite girder bridges.
