Removing the shrinkage effect from short-term moment-curvature and tension-stiffening relations

Abstract

Shrinkage is important, although most frequently neglected, effect related to the constitutive modelling of reinforced concrete (RC). In the general practice, shrinkage along with creep is taken into account in pre-stress loss and/or long-term deformation analysis. However, even at the first loading, free shrinkage strain of concrete may be of magnitude that exceeds the cracking strain. Due to restraining action of a stiff reinforcement, shrinkage induces tension stresses in the concrete that might significantly reduce the crack resistance and, consequently, increase deformations of RC members. This paper presents a numerical procedure for removing shrinkage from moment-curvature and tension-stiffening relations. Based on this procedure, the shrinkage-free relations are derived using the test data of two RC beams.