Discrete cracks approach for deformational analysis of reinforced concrete beams

Abstract

The discrete cracks approach is proposed for deformational analysis of reinforced concrete members as an alternative method of the classical smeared crack techniques. It evaluates analytically the effects of concrete shrinkage, developed in a period before loading, and bond at the contact interface of reinforcing bars and surrounding concrete. Consequently, the history of evolution of the major, discrete cracks patterns is considered at a monotonically increased loading. The cracking process is analyzed by superposing the symmetrical and asymmetrical bond problems during it. The asymmetrical problem is resolved by introducing the increments of forces and bending moments due to appearance of major cracks. The proposed approach is applied for prediction of the stress-strain state and deflections of the beams with different ratios of reinforcement. The mid-span deflections, calculated using the discrete cracks model, agree sufficiently well with those obtained by the Eurocode-2 technique based on the smeared crack approach. The tension stiffening effect is clearly indicated for the beam with a small reinforcement ratio.