Experimental and numerical investigations on monotonic tensile behavior of grouted sleeve couplers with different splicing configurations

This study presents experimental and numerical investigations on the tensile behavior of grouted sleeve (GS) couplers splicing steel bars with transition splicing and different strength grades intended for use in shifted plastic hinge applications. Sixteen GS specimens, with testing parameters that included GS coupler size, steel bar diameter, and transition splicing index, were assembled and tested under static monotonic tensile tests. Also, one-dimensional finite element (FE) modeling was conducted to establish the bond–slip constitutive models, which govern the bar–grout interfaces at different regions of the GS coupler, by inverse analysis. Experimental results showed consistent failure mode, which was bar rupture away from the coupler region, for all splicing configurations of GS couplers, which demonstrated the ability of GS couplers to fully develop the ultimate stress in the spliced bars. Results also revealed an approximately piecewise linear relationship that governs the ratio between the strain within the coupler region and strain in the spliced normal strength steel bar, in which the strain ratio decreases with larger sleeve sizes and higher transition indices. Furthermore, results showed that GS couplers exhibited considerable slip that increased with bar size and can be of benefit to GS precast members that are subjected to significant rotation demands. The proposed bond–slip models for GS couplers were simple but accurate in slip prediction and they can be very helpful in the analytical modeling of precast members containing GS couplers. •Tensile behavior of GS couplers with transition splicing was investigated.•Consistent failure mode was observed: bar rupture away from the coupler region.•Piecewise linear law was observed for the GS region and normal grade bar strain.•Larger GS couplers with higher transition indices had lower strain ratios.•Bond–slip models for GS couplers were proposed.