Tension-stiffening behaviour of reinforced concrete ties of various strength classes

Abstract

A new law of tension-stiffening for reinforced concrete (RC) ties is proposed in the present study. It is based on the test data of 11 experimental programs of RC elements of various strength classes reported in the literature. The experimental programs covered a wide range of characteristics of mechanical and geometrical parameters of specimens such as compressive strength of concrete, reinforcement ratio and diameter of reinforcement bars. By eliminating the effect of shrinkage from the test load-strain diagrams of the ties, a simple model with no dependence on reinforcement ratio could be derived. The proposed tension-stiffening law is compared with the formulation in Eurocode 2. Statistical analysis of strain predictions of RC ties based on Eurocode 2 was conducted. It is found that the Eurocode 2 significantly underestimated strains in the RC ties with the errors reaching 50% for the lightly reinforced members. Nevertheless, when shrinkage effect was accounted for in the test load-strain diagrams, the predictive capability of the Eurocode 2 formulation could be significantly improved.