Test and Simulation on Bond Behavior Between Sleeve Grout and High Strength Steel Rebar

Abstract:

Bond behaviors of sleeve grout and high strength steel rebar were investigated for the grouted sleeve connection. Taking the diameter of steel rebar and its embedded length into account， the pull-out test with 27 specimens was employed to investigate the bond behaviors between sleeve grout and steel rebar. Based on the test results， it is found that there are three failure patterns of specimens after loading， namely， steel rebar fracture， bond-slip failure and splitting failure， which were affected by the diameter of steel rebar and its embedded length especially. In addition， there is a sudden drop with a range of 0.1 to 0.3 times peak load in the initial decline part of load versus slip curves of specimens with bond-slip failure. Furthermore， bond-slip constitution models were initiated， and expressions of the bond strength， peak slip and residual bond strength were built by the data fitting for the specimens with bond-slip failure. Finally， the finite element analysis was used to stretch these previous expressions. Combined with the results of simulation and the test， it is found that the embedded length of steel rebars with a diameter （d） of 12mm， 16mm and 18mm should not be less than 5d， 7d and 7d respectively when the failure mode of rebar fracture occurs to the pull-out test. These findings are beneficial to the design of the grouted sleeve connection and form its bearing capacity calculation method in the further study.

Key words:sleeve grout;pull-out test;finite element numerical simulation;bond-slip constitution model;bond strength