Performance and confining mechanism of grouted deformed pipe splice under tensile load

In this study, a new type of grout-filled coupling sleeve was presented. The sleeve was fabricated with a standard seamless steel pipe through cold rolling techniques and characterized by its unique processing method and configuration. Based on this sleeve, 11 coupler specimens of four categories with embedment length from 7 to 7.5 times bar diameter were prepared and tested under tensile load to study the failure modes, structural performance, and confining mechanism of the splice. Test results clearly indicated that this kind of splice provided satisfactory behavior of which the ultimate tensile strength all exceeded the required loading capacity specified in ACI318 and JGJ107. Furthermore, it was found that the inner cavity structure of grouted sleeve had great influence on the confinement, which consequently affected the bond performance of spliced bar. Based on the experimental results, equations were derived to calculate the confining interface pressures and the bond resistance of the spliced bar, and the calculated ultimate load showed a good agreement with the experimental value.