Measured Behavior and Thermal Gradients in Innovative Bridge Piers

Construction of the U.S. 183 elevated highway in Ausitn, Texas, provided a unique oppotunity to investigate the behavior of two types of innovative concrete piers. TIed Y shape piers were used to support mainlane spans. They were cast in situ with steel pipes for the tensile ties between the arms of the Y. Force distribution and thermal gradients and effects were measured prior to and during construction of the superstructure. Force measurements were compared to conventional and to strut-and-tie model analyses. The second type of piers were tall segmentally constructed hollow box piers. Tempertature gradient and strain data were obtained to evaluate design thermal gradients and thermal gradient design procedures. Recommendations for improvement in design specifications are presented.