Double-Counting Problem of FEA with Simultaneous Use of Bond Link Elements and Tension-Stiffening Model

Abstract

This paper presents an analytical investigation of the double-counting problem in finite element analyses in which bond link elements, discrete reinforcement elements, and tension-stiffening models are used simultaneously. Engineers and researchers often use the bond link elements in the FEA to express bond slip between reinforcing bar and concrete. On the other hand, in case of smeared crack modeling, bond behavior is indirectly expressed by a tension-stiffening model of concrete. If the bond link elements and tension-stiffening models are used simultaneously, there is some concern that the effect of the bond is double counted. Hence, example uniaxial tension specimens are analyzed by three different analysis methods to investigate the double-counting effect. (1) Smeared crack analyses present no double-counting effect while (2) discrete crack analyses cause the double counting of tensile concrete stresses and result in over cracking. (3) Discrete crack analyses with delayed cracking also cause double counting although over cracking does not occur but the tension-stiffening relationships are overestimated.