Study on the Influence of the Confinement Effect on the Bond Strength Recovery in the Defective Grouted Sleeve Connection

Defects emanating from the onsite operation of the grouted sleeve connector have a significant impact on the ultimate tensile capacity of the connector. In this research, an experiment on the capacity of the fully grouted sleeve connector considering different configurations of defects was carried out. The experiment results indicated that the connector is highly sensitive to the location of the defects, which engenders a drop of 15% in the ultimate capacity of the connector. Based on the accurate simulation of the experiment model, a series of parametric analyses were conducted to evaluate the interaction of defects with other mechanical properties of the connector. It was found that the different values of the ratio of the sleeve diameter to that of the bar within the design recommended interval significantly influence the connection's performance. The lowest ratio value engenders approximately 10% to 16% of tensile strength recovery in the weakened configuration, while a bigger ratio value engenders a decline in the capacity. This work proposes the incorporation of a safety constant in the average bond expression.