Cyclic Behavior of Precast Segmental UHPFRC Bridge Columns with Replaceable Damage-Concentrated Elements

A novel precast segmental bridge column was put forward innovatively to contribute to accelerated bridge construction and rapid repair of bridge after earthquake, which is in accordance with the theme called engineering innovations for rapid urbanisation. The proposed bridge column was manufactured with cost-effective ultrahigh performance fiber-reinforced concrete (UHPFRC) incorporating river sand and coarse aggregate. As the potential damaged region, the bottom segment was composed of three parts: inner core zone designed to bear axial loading, outer replaceable UHPFRC plates (RUP) designed to bear lateral loading, and middle replaceable steel dissipaters (RSD) designed to enhance energy dissipation (ED), when the entire bridge structure was subjected to earthquake shock. The rapid repair after earthquake was completed with substitutions of replaceable damage-concentrated elements including RUP and RSD. Cyclic loading tests were conducted on three 1:3 scaled specimens and their repaired specimens. The research parameters included posttensioning (PT) force level and usage of RSD. Test results show that both construction and repair can be very time-saving for the proposed bridge column. Major damage focuses on replaceable damage-concentrated elements while remaining parts are basically intact. All the specimens present good deformation capacity and excellent self-centering feature. Two different failure modes can be found: some specimens failed in the lateral bearing capacity while others failed in the ED capacity. Compared with the original specimen failed in the same failure mode, the repaired specimen has similar lateral bearing capacity and deformation capacity but seriously weakened initial stiffness.