Reinforced concrete elements have an inherent resistance to applied torque due to the geometry of their cross-section. Nevertheless, the resulting stress due to applied torque is additive to other actions, such as bending moments, and axial and shear forces.
This Technical Guidance Note discusses the impact torsion has on the design and detailing of reinforced concrete elements. It should be read in conjunction with Level 1, No. 21 How to avoid torsion