STRUT-AND-TIE MODELLING OF REINFORCED CONCRETE DEEP BEAMS

Abstract

A compatibility-based strut-and-tie model which takes into account constitutive laws for cracked reinforced concrete, strain compatibility and employs a secant stiffness formulation has been proposed for estimating the capacity of simply-supported reinforced concrete deep beams under four-point loading. The proposed method recognizes failure modes like crushing of nodal zones, yielding of longitudinal reinforcement and crushing failure of the diagonal strut. The predictive accuracy of the proposed method has been evaluated by comparing its predictions with the test results of 145 deep beams reported in the literature. Accurate and conservative predictions with a mean value of the test-to-predicted results of 1.38 and a coefficient of variation of 0.19 were obtained using the proposed approach which offers a more rational basis for estimating deep beam capacities compared to the simple equilibrium-based strut-and-tie models.