Evaluation of Damaged RC Columns with GFRP-Strip Device

Abstract

Damage of reinforced-concrete (RC) structures commonly occurs during major earthquakes, and becomes worse because of aftershocks. For these reasons, repair technology for seismic damage is needed to prevent possible collapse of damaged RC structures before aftershocks. In this paper, a seismic retrofitting device is proposed to improve the seismic performance of damaged RC columns using glass fiber–reinforced polymer (GFRP), which can be easy to install and quick to repair. The proposed GFRP-strip device consists of a GFRP-composite strip and aluminum clip connectors, used to increase the shear strength of the damaged column. Three RC specimens were constructed with reference to existing RC structures. Two of the specimens were damaged before installing the GFRP-strip devices. After the pretest damage was done, the GFRP-strip devices were installed along the plastic-hinge regions on both ends of the test columns. A comparison of the experimental results indicates that the seismic performance of the damaged RC columns with the GFRP-strip device was improved, and that the shear-failure mode of the RC columns was changed to ductile-flexural-failure mode. According to these results, the maximum strength, accumulated-dissipated energy, and displacement ductility of the retrofitted specimens was increased. Therefore, the proposed GFRP-strip device can be used to improve the seismic performance of damaged RC columns.