RESEARCH ON THE CONSTITUTIVE RELATIONS OF CORRODED STIRRUPS

In this paper, 302 corroded stirrups were obtained by breaking the reinforced concrete beams in chloride environment. Tensile tests were conducted to investigate the effects of the corrosion ratio of sectional area of stirrups on the mechanical properties such as ultimate strain, ultimate strength, yield strength and constitutive relation. It was found that: (1) the stress-strain curves of the corroded stirrups became gentle and the yield plateau became shorter or even disappeared with the increase of corrosion ratio of sectional area of stirrups; (2) the ultimate strength and the ultimate strain degenerated as the increase of corrosion ratio, and the higher the levels of yield strength of the stirrups, the faster the decline of the ultimate strength and the ultimate strain. Based on these findings, a constitutive relation model for corroded stirrups was suggested. An application of the proposed model to the experimental curves demonstrates that the present model gives a good representation of the behaviour of the stress-strain response of corroded stirrups.