Testing of integral abutments

The need for expansion joints arises from the phenomenon of thermal expansion and contraction in bridge structures. However, joints create problems associated with maintenance and cost. Specifically, water can penetrate these joints and accelerate corrosion of the structural elements. Dating to the 1930's, bridges were being constructed as continuous members without joints, termed integral abutment bridges. While integral abutments eliminated maintenance and cost problems associated with jointed bridges, they created the problem of how to resist expansion and contraction. The Tennessee Department of Transportation (TDOT) is among many states that are using integral abutment bridge systems. However, as the lengths of jointless bridges have been increased, the need for information concerning behavior of integral abutment bridges has arisen. This need led TDOT to sponsor research at The University of Tennessee, Knoxville to investigate the behavior of piles supporting integral abutments. The research is being conducted on the Duchtown Road - Pellissippi Parkway interchange construction site. A 40-ft. HP 10 x 42 pile was driven into the ground and a concrete abutment and slab/beam was cast on the pile to simulate the integral abutment system. The test data necessary to determine integral abutment and pile behavior were collected through the use of strain gages, pressure sensors. Linear Variable Differential Transformer (LVDT), and load cells. The malfunctioning of strain gages presented a significant problem to this research project. A method accounting for missing strain gages is presented. The lack of information in the area of concrete abutment behavior is evident from a review of literature, and with the use of increased bridge lengths, this information will be needed. Significant observations were made on the behavior of the concrete abutment. Field data were used to explain the observed abutment behavior.