Title: A multifiber beam model coupling torsional warping and damage for reinforced concrete structures
Abstract: This paper is dedicated to the numerical modelling of structures using multifibre beam elements. A formulation is developed to account for torsional warping in the deformations of an arbitrary-shaped composite cross section. The resulting warping profiles are validated by comparison with the axial displacements obtained by three-dimensional modelling of beams in torsion. The warping kinematics is then implemented in a Timoshenko multifibre beam element. The material is modelled by a 3D damage law, and warping is updated throughout the computations to account for damage evolution. Non-linear parameters of the constitutive model are identified using a genetic algorithm. A comparison of torque–twist curves predicted with enhanced and classical beam elements to experimental curves highlights the importance of including warping in the model. The analysis of damage patterns further ascertains the effect of warping.