Numerical investigation on the shear behavior of slender reinforced concrete beams without shear reinforcement differed by various boundary and loading conditions

Abstract

This paper presents a numerical investigation on the shear behaviour of reinforced concrete beams without shear reinforcement differed by two boundary conditions, i.e., cantilever and simply supported beam, and two loading configurations, i.e., one-point and uniformly distributed load. The finite element models are exactly constructed as specimens of an experimental program that investigates the effect of the bending moment on the shear response of members without shear reinforcement. Similar to the experimental observations, the finite element analyses show general differences in the shear resistance of members having the same cross-sectional properties but diverse M/V–combinations resulting from different support and loading conditions. For the same cross-sectional parameters, the shear resistance of the simply supported beam subjected to a uniformly distributed load is higher than that of cantilevers subjected to a concentrated load, and the shear resistance of the cantilevers subjected to a uniformly distributed load is higher than that of the simply supported beam. Through finite element analysis, more insight of this effect can be obtained by the investigations of the strain profile in the cross-section, the principal stress within the shear span, and the stress distribution at the longitudinal flexural reinforcement. Furthermore, the difference between the shear force at the critical shear crack formation and the maximum load-carrying capacity is distinguished by analyzing the governing load transfer mechanism. The validated FE models are used to investigate the influence of shear slenderness on the shear resistance of beams by various boundary and loading conditions. A comparison to the shear resistances predicted by design equations proposed in some codes of practice is also provided.