Design and Construction of a Reinforcement Free Concrete Bridge Deck on Precast Bulb Tee Girders

This presentation describes the concepts involved in design and construction of a reinforcement-free bridge deck intended to provide cost effective, durable and more rapid construction for highway bridges. The new wide flanged or bulb tee precast prestressed concrete girder sections currently used in bridges allow for a shorter effective span for the bridge deck because of the wide girder flanges. The failure mode of concrete decks on these girders is expected to be a punching shear mode as the span of the deck becomes shorter. The shear forces from the vehicle wheel loads in the deck of this innovative bridge are designed to be carried by restrained membrane action without using reinforcing in the concrete. The restrained membrane action is enhanced by the natural lateral stiffness of the wide girder flanges and by tying adjacent girders together with steel tie rods placed between the webs. A construction case study of the newly developed system as applied by the Wisconsin DOT in a prototype bridge on a U.S. highway and the relevant development and testing conducted by the University is included.