Seismic performance of segmental precast unbonded posttensioned concrete bridge columns

The seismic performance of segmental precast unbonded posttensioned bridge columns with hollow cross sections is investigated in this paper. Bonded longitudinal mild steel reinforcement crossing the column segment joints is provided to enhance the hysteretic energy dissipation of the columns, also referred to as energy dissipation (ED) bars in this paper. The ED bars are detailed to provide energy dissipation without premature fracture at the critical column segment joint. For design purposes, a simplified analytical model to predict the lateral force-displacement response (pushover curve) is proposed. Moreover, a detailed three-dimensional (3D) finite-element (FE) model is developed and utilized to predict the behavior of segmental columns under cyclic loading. Parametric studies using the simplified analytical model and the 3D FE model are conducted to investigate the seismic behavior of this type of column construction. At the end of this paper, the comparisons of the results of the response-history analyses between the segmental columns with flag-shape hysteretic behavior and their comparable conventional counterparts are given.