Calcul de la rigidité de torsion des poutres en béton armé fissurées en flexion

This paper proposes a method to calculate the torsional stiffness of reinforced concrete beams with section of any shape, in a cracked state due to bending, subjected to small torque (shape stability problems). The simultaneous influence of the various parameters (shape of the section, state of cracking, longitudinal reinforcement) is taken into account. A series of laboratory tests on beams with hollow, massive, or double-tee thin cross sections gives data to determine semi-empirically some parameters. Calculated and experimental stiffnesses are in rather good agreement. The proposed method fills in a gap in the nonlinear calculation of reinforced concrete. Key words: reinforced concrete, flexural cracking, torsional stiffness, calculation method, nonlinear elasticity, stability.