Experimental study on mechanical properties of high strength rebar grouted sleeve connection with ultra-high strength grouting material
The grouted sleeve connection is the mainstream of rebar splicing in the precast concrete structures,and the precast component with 500MPa high strength rebar can effectively improve the bearing capacity and economy of connections and canponents.Twelve grouted sleeve connection specimens with the effect of anchorage length,grouting material strength and rebar strength are designed and analyzed by uniaxial tensile loading test,so the failure modes,strain distribution and working mechanism of the specimens are observed and obtained.The results show that the connection mainly occurs steel bar necking failure,and the load-displacement curve mainly contains linear growth stage,yield stage,strengthening stage and necking failure stage.The grouted sleeve connection with 120MPa ultra-high strength grouting material can all satisfy the requirement of residual deformation.The rebar and sleeve axial strain,sleeve hoop strain and constraining effect in the middle of sleeve are gradually decreasing with the increase of anchorage length,and the rebar and sleeve are uniformly stressed.For 500MPa rebar grouted sleeve connection with 85MPa and 120MPa grouting materials,the recommended anchorage lengths of 10d and 8d respectively.Finally,the bonding force between sleeve and grouting material,the bonding force between rebar and grouting material,and the tensile bearing force of rebar in the high strength rebar grouted sleeve connection can be accurately calculated by the theoretical analysis,and the failure mode of the connection can also be predicted.
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