Experimental study on the effects of sleeve characteristics on grouted connection performance

This study investigates the effects of sleeve characteristics on the mechanical performance of grouted sleeve connections through two experimental investigations. Four sleeve types with five different specifications were selected. The first investigation focused on the effect of reinforcement-to-sleeve clearance, involving 60 specimens subjected to unidirectional tensile test. The second examined the effects of sleeve material and internal construction through 36 specimens under the unidirectional tensile test, high-stress cyclic tension-compression test, and largedeformation cyclic tension-compression test. The results indicate that the increased reinforcement-to-sleeve clearance reduces connection strengths and increases deformation. Nevertheless, all specimens, including those with a sixgrade size mismatch, satisfied the performance requirements in current specifications, suggesting that the existing provisions are relatively conservative. In addition, internal ribs and shear grooves within the sleeve can enhance load transfer, but the effectiveness diminishes as clearance increases. During cyclic tension-compression loading, tensile fracture was the primary failure mode with specimens satisfying the specified strength and deformation criteria. Residual deformations and stiffness degradation were observed but remained within acceptable limits. Furthermore, sleeve material and construction influenced the overall stiffness of connections. Ductile cast iron sleeves demonstrated the highest stiffness, followed by machined steel sleeves, while rolled steel sleeves showing the lowest. These findings provide valuable experimental evidence for optimizing sleeve design and improving the reliability and efficiency of grouted connections in prefabricated construction.