QUASI-STATIC TEST STUDY ON PRECAST ECC CONCRETE-FILLED TUBULAR BRIDGE PIERS

A precast ECC concrete filled tubular pier is proposed. To investigate the seismic performance of the novel pier, 1 normal reinforced concrete pier specimen (RC) and 3 precast ECC concrete-filled tubular pier specimens (ECC1~ECC3) are designed and fabricated, among which specimen ECC1 is a reference, specimens ECC2 and ECC3 are employed to study the influence of the axial compression ratio and of the section in plastic hinge region, respectively. The specimens are tested under the action of a pseudo-static load to obtain crack propagations, failure modes and hysteretic curves. The indicators of seismic performance (bearing capacity, energy dissipation, ductility coefficient, stiffness degradation, residual displacement, etc.) are also analyzed. It can be observed that the reinforcement buckling after concrete broken in normal RC piers is prevented by the precast ECC tube, which enables the novel pier with an improved failure mode, enhanced deformation capacity and reduced damage severity. Compared with normal RC piers, the novel piers exhibit better energy dissipation capacity. The bearing capacity and ductility coefficient of specimen ECC1 are 16.66% and 42.15% higher than those of specimen RC, respectively. The novel pier with a lower axial compression ratio fails with less cracks in the ECC tube, and exhibits poorer energy dissipation, lower bearing capacity, better deformability, and slower stiffness degradation. Besides, casting ECC in a precast ECC tube in the plastic hinge region can enhances the energy dissipation, bearing capacity, and deformability, but has little influence on the crack propagation.