Bond behavior of spirally confined bar splices in grout

Abstract

Despite various studies on the bond behavior of Glass-Fiber Reinforced Polymer (GFRP), an available literature on the bond behavior of GFRP bars in grouted confined by spiral is limited. In the present study, the bond behaviour of deformed steel and GFRP reinforcing bars connected by a grouted spiral connection was investigated. Flexural pull-out test was performed on 24 beam specimens to evaluate the bar bond strength. The test parameters were the spiral diameter and pitch distance. The test results showed that the spiral confinement significantly improved the bond performance of GFRP bars and deformed steel main bars. The bond strength of GFRP was decreased by damage of the outer layer of GFRP bars due to detachment of sand grains on the GFRP bar surface. As the spiral diameter decreased from 45 to 25 mm, the bond strength increased by 9.7 ~ 14.5% due to higher confinement stress. In the deformed steel reinforcing bars, the reduced spiral diameter increased the bond strength by 40%.