Fatigue Failure Criterion for Deformed Bars Subjected to Large Deformation Reversals

This paper describes how, after the Hanshin-Awaji earthquake, the volume of lateral reinforcement used in reinforced concrete structures in Japan was increased in order to improve seismic performance. Although a large volume of closely spaced lateral reinforcement will be effective in preventing elastic buckling of the longitudinal reinforcement, it does not prevent plastic buckling. Under severe earthquake loading, longitudinal reinforcement will be subjected to large reversed-cyclic deformation demands into the plastic regime in tension and the buckling regime in compression. The paper presents the results of low cycle fatigue testing of deformed bars and examination of failure criteria for these bars.