Cyclic behavior of existing flexure-dominated RC bridge columns retrofitted by ECC jackets in the region of plastic hinge

Abstract

Engineered cementitious composites (ECC) has been implemented to the region of plastic hinge of new-constructed RC bridge column for enhancing the seismic performance. In this study, it is proposed to use ECC jacket as exterior jacketing in the region of plastic hinge for retrofitting seismic performance of existing flexure-dominated RC bridge columns. In order to clarify the effect of ECC jackets for enhancing the seismic performance of existing bridge columns, both experimental and numerical investigations were conducted in this study. Four 1/5-scaled RC bridge columns including one conventional RC column and the rest of three retrofitted by ECC jackets with varying thickness and heights in the region of plastic hinge were tested under the cyclic load. The experimental results revealed that the ECC jacket is capable of retrofitting the seismic performance of existing flexure-dominated RC bridge columns in terms of mitigating damage, increasing load-carrying capacity, ductility and energy dissipation capacity. The initial stiffness and load carrying capacity increases as the increase in the thickness of jackets. Furthermore, numerical study based on the fiber element method were conducted and the results agreed well with experiments. It was found that the thickness of ECC jacket was more important than height of jacket in enhancing the seismic performance of retrofitted RC columns on condition that ECC jacket was higher than the minimum height of plastic hinge specified by seismic code. .