Integral abutment bridges are joint-less bridges where the deck is continuous and connected monolithically with the abutment walls. These bridges accommodate superstructure movements without conventional expansion joints.
With the superstructure rigidly connected to the substructure and with flexible substructure piling, the superstructure is permitted to expand and contract. Approach slabs, connected to the abutment and deck slab with reinforcement, move with the superstructure. At its junction to the approach pavement, the approach slab may be supported by a sleeper slab. If a sleeper slab is not utilized, the superstructure movement is accommodated using flexible pavement joints.
Due to the elimination of the bridge deck expansion joints, construction and maintenance costs are reduced.
The integral abutment bridge concept is based on the hypothesis that due to the flexibility of the piling, thermal (or seismic) stresses are transferred to the substructure by way of a rigid connection between the superstructure and substructure. The concrete abutment contains sufficient bulk to be considered a rigid mass. A positive connection with the ends of the beams or girders is provided by rigidly connecting the beams or girders and by encasing them in reinforced concrete.