Behavior of Prestressed Concrete Piles Supporting Integral Abutments

Joints in bridges have historically led to various in-service problems, the presence of which led bridge design engineers in some states to design bridges of relatively short lengths to be jointless. Successful design of these bridges led to the design of jointless bridges of longer lengths. While not a pioneer in the use of jointless bridges, the Tennessee Department of Transportation (TDOT) has in recent years extended the limiting boundaries for jointless bridges to unprecedented lengths. A series of field tests on prestressed concrete piles supporting integral abutments was sponsored by TDOT and performed by personnel from The University of Tennessee, Knoxville. Lateral load was applied to the simulated abutment to produce a horizontal deflection at the top of the pile. Rotation of the pile was restrained by the hold-down beams to simulate the restraint provided by the bridge deck system in an integral abutment bridge. The loading was applied in most of the tests at a rate of 25.4 mm (1 in.) in 4 hours to simulate the expansion and contraction in a bridge due to temperature change. The primary objectives of this paper are (a) to describe the tests performed on the four prestressed piles, (2) to present some typical results, and (3) to discuss the feasibility of using prestressed concrete piles in integral abutment bridges designed according to TDOT's criteria.