Influence of bar diameter on low-cycle fatigue degradation of reinforcing bars

This paper reports the results of 120 low-cycle fatigue tests on steel reinforcing bars with varying slenderness ratios at varying strain amplitudes. The failure modes of the fractured bars were investigated through analysis of the fracture mechanisms of bars. The results of experimental testing were used to update empirical models of low-cycle fatigue life for such bars. The newly improved empirical models were then incorporated into a recently developed constitutive material model that accounts for bar buckling and fatigue. The experimental results show that the size effect is significant for short steel reinforcing bars where there is no buckling. The results also show that as the slenderness ratio of the steel reinforcing bars increases, the influence of the bar diameter on low-cycle fatigue reduces.