Cyclic tests of precast segmental unbonded post-tensioned concrete bridge piers

This paper presents an experimental study on seismic performance of precast segmental unbonded posttensioned concrete bridge piers. The pier specimen consists of a foundation, 4 hollow column segments, and a pier cap with a height of 5.7m. The prestressing tendons are located inside the hollow core of the pier column and hence are unbonded with the surrounding concrete. In the first specimen, no mild steel reinforcement is extended across the column segment joints. In the other 2 specimens, longitudinal mild steel bars, also referred to as energy dissipation bars, anchored at the foundation and extended up to the pier cap, are added to enhance the seismic energy dissipation. Test results show that all pier specimens exhibited satisfactory ductile behavior. The hysteric energy dissipation, lateral strength, and residual drift upon unloading of the specimens increased with the increase of the amount of energy dissipation bars.