This model incorporated for the first time smeared constitutive laws, or smeared stress ( σ)-strain ( ε) relationships, for both tensile steel reinforcement embedded in concrete and compressive concrete. The model satisfies the three Navier’s principles of the mechanics of materials, namely, stress equilibrium, strain compatibility and constitutive laws.Īmong the STA-based models that have been developed, one of the most commonly used and extended is the Variable-Angle Truss Model (VATM), which was originally proposed by Hsu and Mo in 1985. The tube is modeled with a spatial truss, which includes longitudinal and transverse steel reinforcement under tension interacting with inclined concrete struts under compression.
#Crack pour architecte 3d ultimate 17.5 cracked
Ī STA-based model assumes that a reinforced concrete (RC) beam under torsion behaves like a cracked thin tube, where the external torque is resisted through a transversal circulatory shear flow. Models based on the STA constitute the basis models for most codes of practice to establish the design procedures for torsion and still continue to be improved and extended. They are able to simulate the complex 3-dimensional features of the torsional phenomenon, including the nonlinear behavior and the interaction between the material components of the beam in all loading stages. Nowadays, modern truss-based models can be considered reliable, comprehensive and unified analytical models. In the second half of the last century, the Space Truss Analogy (STA) was successively refined in order to better predict the response of structural concrete beams under torsion.
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. 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). The predictions of these parameters from the GSVATM are compared with the experimental results from several reported tests on RC beams under torsion. The studied parameters are the cracking torque and the corresponding twist. Hence, the GSVATM is used to check several smeared constitutive laws for tensile concrete proposed in previous studies. 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. Being a 3-dimensional smeared truss model, the GSVATM must incorporate smeared constitutive laws for the materials, namely for the tensile concrete.
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.
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