Tensile behavior of half grouted sleeve connections: Experimental study and analytical modeling

Half grouted sleeve connections, consisting of a threaded end and a grouted sleeve end, are a convenient and economical solution in joining rebars together in precast concrete construction. In order to study the tensile properties of this connection, 15 half grouted sleeve splices for steel bars were tested under static tensile load. The main parameters of the experimental research are bar diameter, sleeve dimensions and rebar offset. The tests show that the specimens exhibit three categories of failure, namely rebar tension fracture, rebar pull out due to bond failure, and thread shear failure. Rebar offset due to construction error has a negligible influence on the load carrying capacity of the specimen. An analytical model is established to calculate the tensile capacity of the specimens with bond failure considering the confinement effect of the sleeve. Satisfactory agreements are made between the predictions and test results. The issues leading to thread failure are discussed. A design method is proposed to prevent specimens from premature thread failure.