ABSTRACT
Total-strain based membrane models for finite element analysis of reinforced concrete have been developed in Canada and the US and elsewhere and have been used successfully to analyze a variety of concrete structures. A major advantage of the total-strain approach is that consideration of crack widths and crack spacing can be avoided by computing only the average stress and strain in the concrete and smeared steel. Bond/slip behavior is dealt with indirectly using a tension stiffening approach and either fixed or rotating crack models. A fundamental issue with all such models is shear transfer across cracks. Numerous methods for computing the reduced shear modulus, G, have been developed, the simplest being multiplying the shear modulus by a reduction factor, β, which varies between 0 and 1. A method for determining the shear modulus using shear/slip relationships derived by Walraven (1981) was developed by Vecchio (1986). However, this relationship does not apply to cyclic loading. Furthermore, it does not enforce a functional relationship between slip and separation so that ‘‘shear friction’’ behavior is not properly modeled.
