Bond Characteristics in Post-Yield Range of Deformed Bars

Bond characteristics in post-yield range of deformed bars were investigated by means of pull-out test. In the test, the bars were embedded in massive concrete in order to have no effect of splitting crack and unbond region was set at loaded end to have no effect of location along the bar. Bond stress in post-yield range is much lower than that in elastic range and it decreases suddenly with yielding of steel. Slip at the loaded end is mostly controlled by location at which steel bar yields. Bond-slip relationship in post-yield range depends on properties of steel bar such as yield strength, hardening strain and tensile strength. Bond-slip-strain relationship obtained from test in elastic range is applicable in post-yield range. The lower bond stress and different bond-slip relationships can be expressed by the analysis of using the unique bond-slip-strain relationship.