Cyclic loading test for concrete bridge columns integrated with ECC segment at the plastic zone

Abstract The ductility of bridge columns depends on the arrangement of dense hoops at the bottom of column where the plastic hinge forms, but the concrete still experienced severe damage during severe earthquakes, resulting in difficulty in maintenance afterward. In order to reduce the severe damage of concrete at the column bottom under earthquakes, Engineering Cementitious Composites (ECC) was proposed to replace common concrete within a certain height at the plastic hinge zone to form 5 RC-ECC columns with different design details in this study. The cyclic quasi-static test showed that the damage behavior of ECC integrated columns was much less serious than concrete column under the equivalent loading and spalling of ECC did not occur in the whole loading process. ECC can also provide enough lateral restriction to longitudinal bars even without setting lateral reinforcement to avoid their buckling. As a result, columns integrated with ECC can provide excellent energy dissipation capacity and high ultimate bearing capacity with reduced or without lateral hoops. Besides, the study also found that different design heights of ECC segment could cause different failure modes of the columns. The minimum ECC height was then derived based on the test phenomena and theoretical analysis, to ensure that the seismically induced damage appeared only in the ECC segment while the common concrete segment was not damaged.