Bond strength and cyclic bond deterioration of large-diameter bars

A study on the bond strength and cyclic bond deterioration of largediameter reinforcing bars embedded in well-confined concrete is presented. The study included monotonic pullout tests and cyclic pull-pull tests conducted on No. 11, No. 14, and No. 18 (36, 43, and 57 mm) reinforcing bars. The bond stress-slip relations obtained from the tests are presented, and the effects of the compressive strength of concrete, bar size, pull direction (for a vertically cast bar), and slip history on the bond strength are examined. Moreover, a phenomenological bond stress-slip law for monotonic and cyclic loading is proposed for bars embedded in well-confined concrete. This law has been validated with experimental results obtained in this study and in previous research.