Three-dimensional finite-element modelling of normal- and high-strength reinforced concrete members, with special reference to T-beams

Abstract A three-dimensional finite-element model for structural concrete, based on brittle constitutive relationships at the material level, is applied to the analysis of reinforced-concrete members. The generality of the ‘constant-parameter’ finite-element model, previously established for normal-strength concretes, is now extended to high-strength mixes. Emphasis is placed on the modelling of T-beams (encompassing both ranges of concrete strength), for which results from laboratory tests by the authors are available; and, in addition, a high-strength rectangular member is also considered, its testing having been carried out by other workers. Not only is there a general scarcity of reported experimental data for high-strength concrete components but, to the authors' knowledge, no attempt to apply finite-element modelling to this higher range of concrete strengths seems to exist in the literature. The analysis of the various structural components is preceded by the modelling of a particular, normal-strength T-beam, which is studied by adopting a number of mesh discretizations in order to accomplish an economical solution without impairing the accuracy of the numerical predictions. What emerges from the present investigation is that the existing finite-element model, applied in the past to normal-strength concretes, is just as applicable to high-strength mixes. In fact, it appears that the latter type of concrete is even more amenable to simple modelling of complex reinforcement detailing, and a likely explanation for this trend is put forward on the basis of the differing degree of ‘triaxiality’ between normal- and high-strength concretes.