Elongation of Reinforced Concrete Members Subjected to Cyclic Loading

Abstract

Longitudinal elongation develops in reinforced concrete members that exhibit flexural yielding during cyclic loading. The longitudinal elongation can decrease the shear strength and deformation capacity of the members. In the present study, nonlinear truss model analysis was performed to study the elongation mechanism of reinforced concrete beams and the effects of various design variables on the elongation. The results showed that residual tensile plastic strain of the longitudinal reinforcement in the plastic hinge is the primary factor causing the member elongation and that the shear-force transfer mechanism of diagonal concrete struts has a substantial effect on the magnitude of the elongation. Based on the elongation mechanism found by truss model analysis, a simplified method for evaluating member elongation was developed. The proposed method was applied to test specimens with various design parameters and loading conditions.