Effects of spiral diameter on the bond stress-slip relationship in grouted sleeve connector

Abstract

This paper presents the results of experimental tests on splice connectors joining two main steel bars. The objective was to investigate bond strength, slip and failure modes of the connected steel bars confined by the grouted sleeve connectors. A total of 21 grouted splice connectors were tested until failure under increasing axial load. Each sleeve connector consisted of steel pipe, steel spiral with vertical bars and cement grout. The key parameter was the diameter of the spiral reinforcement which confined the splicing of two steel reinforcement bars. The effects of spiral diameter of 35, 45, 55, 65, 75 and 85 mm on the bond strength and slip were critically investigated. The test results indicate that specimens with smaller spiral reinforcement accompanied by four shear keys provide greater bond strength. The improvement in bond strength is due to the confinement provided by the spiral reinforcement which eventually increases the axial tension capacity of the sleeve connector.