Design and field testing of jointless bridges

Jason Matthew Franco, West Virginia University


A recent trend in bridge design has been toward elimination of joints and bearings in the bridge superstructure. These joints and bearings are expensive in both initial and maintenance costs, and can get filled with debris, freeze up and fail in their task to allow expansion and contraction of the superstructure. They are also a "weak link" that can allow deicing chemicals to seep down and corrode bearings and support components. Because the design is difficult and their behavior is unknown, they are not widely used despite the enormous benefits. There are no standardized design procedures for these bridges, only a list of specifications is available. To address this, three bridges were statically load tested every three months for a period of two and a half years. Field data from these tests were used to make recommendations to current design procedures. Design recommendations based on experimental data are given in the form of a design example.