Experimental investigation on UHPC-based gravity-type half grouted sleeve connections under tensile and cyclic loadings

Abstract

This study presents a new connection method using ultra-high performance concrete (UHPC), called UHPC-based gravity-type connection, to overcome the drawbacks of the traditional grouted sleeve connection. Extensive physical experiments were performed to investigate the mechanical performance of the new connection method, including uniaxial tensile loading, high-stress cyclic loading, and large-strain cyclic loading. The primary parameters investigated in the physical experiments included rebar diameter, anchorage length, grouting material type, rebar offset, and disturbance. It was found that the connection performance of the proposed method is superior to the traditional grouted sleeve connection. The required anchorage length of rebars can be reduced by using the new connection method compared to the traditional one. Compared with the uniaxial tensile test, cyclic loading degenerates the bonding performance of the connection so that the required anchorage length is increased from 5.5d to 6.5d. The stress mechanism of the bond failure was addressed for the new connection, and the formula was proposed to estimate its ultimate bond strength.