Evaluation of Smeared Constitutive Laws for Tensile Concrete to Predict the Cracking of RC Beams under Torsion with Smeared Truss Model

Abstract

In this study, the Generalized Softened Variable Angle Truss-Model (GSVATM) is used to predict the response of reinforced concrete (RC) beams under torsion at the early loading stages, namely the transition from the uncracked to the cracked stage. Being a 3-dimensional smeared truss model, the GSVATM must incorporate smeared constitutive laws for the materials, namely for the tensile concrete. Different smeared constitutive laws for tensile concrete can be found in the literature, which could lead to different predictions for the torsional response of RC beams at the earlier stages. Hence, the GSVATM is used to check several smeared constitutive laws for tensile concrete proposed in previous studies. The studied parameters are the cracking torque and the corresponding twist. The predictions of these parameters from the GSVATM are compared with the experimental results from several reported tests on RC beams under torsion. From the obtained results and the performed comparative analyses, one of the checked smeared constitutive laws for tensile concrete was found to lead to good predictions for the cracking torque of the RC beams regardless of the cross-section type (plain or hollow). Such a result could be useful to help with choosing the best constitutive laws to be incorporated into the smeared truss models to predict the response of RC beams under torsion.

Torsional strengthening using carbon fiber reinforced polymer of reinforced concrete beams subject to combined bending, shear and torsion

“…In many instances, reinforced concrete (RC) beams in buildings and other structures are subject to complex loading including shear, bending, and torsion. Well known analytical approaches such as the softened truss model (Hsu and Mo, 1985; Hsu, 1993; Jeng and Hsu, 2009; Teixeira and Bernardo, 2021) or modified compression field theory (Mitchell and Collins, 1974; Rahal, 2021; Vecchio and Collins, 1986) are able to account for such complex loading and provide adequate bases for the design of new construction. However, for existing structural members requiring repair or strengthening to mitigate deterioration, and/or to increase capacity, existing literature does not provide sufficient experimental data or an analytical approach to designing the strengthening measures, particularly for torsional loads.…”

Editorial for “Mechanical Behavior of Concrete Materials and Structures: Experimental Evidence and Analytical Models”

“…It was also demonstrated that the accuracy of the proposed equations is superior to that of alternative code-based formulations. The torsional behavior of RC beams, with particular attention to the transition from the uncracked to the cracked stage, was also investigated by Teixeira and Bernardo [ 11 ] through the generalized softened variable angle truss-model (GSVATM). The GSVATM was used to check the accuracy of some smeared constitutive laws for tensile concrete proposed in the literature.…”