A new analytical approach in modelling of cracking of RC members

Abstract

Cracking is one of the most complicated phenomena of concrete structures. Multiple theoretical models have been proposed to predict cracking characteristics, but most rely on empiricism. The present paper proposes a simple, mechanically sound and transparent analytical approach for crack distance analysis of RC ties. The philosophy behind the proposed methodology is to establish the mean crack spacing through the compatibility of the discrete cracking and smeared cracking approaches. The mean crack spacing is obtained by equating the mean strains of both approaches. The bond stress-transfer approach governs the strain distribution of the reinforcement between the consecutive cracks, whereas the smeared approach provides the estimated mean strain of the element. The mean crack spacing can be determined for any bar diameter and reinforcement ratio combination in relation to a single mean crack distance established experimentally for the reference RC member. To ensure compatibility between the bond stresses and the applied load, the concept of damage zones is introduced: bond in the area adjacent to the cracks is considered to be fully damaged. A mean crack spacing model derived using the load-strain analysis method of the Eurocode 2 was shown to be in good agreement with experimental data of RC ties.