Effect of Confinement on Bond Splitting Behavior in Reinforced Concrete Beams

Previous experiments have shown that confinement by lateral reinforcement was effective to improve bond behavior of longitudinal bars in a reinforced concrete member. Design formulas for bond splitting strength have been previously proposed based on these experiments. However, little evaluation of confinement stress provided by lateral reinforcement and cover concrete has been conducted. In this paper, the relationship between bond stress and confinement stress of lateral reinforcement is obtained from experiments on beams. An analytical method is presented to evaluate confinement stress. The effect of the confinement stress on bond splitting behavior is discussed. Ultimate bond stress is evaluated from the analytical results.