RESEARCH ON DYNAMICALLY MECHANICAL PROPERTIES OF SEMI-GROUTING AND FULL-GROUTED SLEEVE CONNECTION

The dynamically mechanical performance tests of 47 specimens in three loading rates of 0.6 mm/s, 6.0 mm/s and 60.0 mm/s were performed to study the influence of rebar diameters, loading rates and grouting forms on connection performances compare and analyze the mechanical properties between semi-grouting comection and full-grouted sleeve connection all other factors being equal, and study the influence of sleeve connection methods on comection performances. The formulas of the dynamic bearing capacity and stiffness for the comection of full-grouted sleeve were proposed.The results showed that the failure modes of the specimens at different loading rates were basically the same, all in which were tensile failure of rebars; pull-out failure of rebars and sleeve slip failure only occured in a few specimens. The yield loads and ultimate bearing capacity of the sleeve connection increased with the increase of the diameter of the steel bars; at loading rates of 0.6 mm/s, 6.0 mm/s and 60.0 mm/s, the dynamic loads had little effect on the semi-grouted sleeve connection. With the increase of loading rates, the bearing capacity of the full-grouted sleeve specimens showed an increasing trend as a whole, and the dynamic bearing capacity was higher than the static bearing capacity. The diameter of rebars is an important factor influencing the dynamic stiffness of sleeve grouting connections. As the increcpse the diameter of rebars, the stiffness of specimens increased but the loading rate had a little influence on the stittness when the diameter of rebars was the same.