Numerical Investigation of Mechanical Behavior of Rebar Connections with Sleeves Filled with Expanding Grout

Conventional rebar splicing methods, including lap splices, welded connections, and mechanical couplers, exhibit significant limitations. In comparison, mechanical splices utilizing grout-filled expansive sleeves have demonstrated superior performance. However, these connections typically require substantial sleeve lengths, and the grout's expansion coefficient plays a pivotal role in their structural behavior. Previous studies have determined sleeve lengths without adequately accounting for the expansion coefficient's influence. This study investigates the effect of the expansion coefficient on determining the optimal sleeve length for mechanical rebar connections using expansive grout-filled sleeves. Finite element analysis was performed using ABAQUS software. The results reveal that insufficient expansion coefficients lead to inadequate confining pressure, resulting in rebar slippage, while excessive coefficients cause sleeve yielding and subsequent loss of confinement pressure. Notably, this study successfully reduced the required embedment length to ۵ times the rebar diameter on each side, a significant improvement compared to the ۸ times diameter specified in previous research. The findings demonstrate that through optimized sleeve thickness, grout properties, and expansion coefficient selection, this connection method can effectively replace conventional rebar splicing techniques.

Keywords:

Rebar connection , expansive grout , steel sleeve , finite element modeling , grout expansion coefficient