An enhanced multi-fiber beam–column element suitable for the analysis of reinforced concrete members including the torsional effect is presented in this paper. The model is developed based on displacement formulation with the assumptions of small displacement. The section kinematics is based on the assumptions of a two-node Timoshenko beam and enhanced by introducing additional degrees of freedom at each section in order to take into account the warping phenomenon. For this, a system of fixed points is created and interpolated by Lagrange functions and polynomials. To take into account the effect of stirrups, a discretization of control sections into regions following its material response is applied. The basic assumption of the modified compression field theory with a secant-stiffness formulation is used to represent the constitutive material model for reinforced concrete. The model is validated by comparison with analytical solutions and several experimental tests. The simulations include a variety of monotonic load conditions under bending, shear and torsion for specimens with rectangular sections.

本文提出了一种增强的多纤维梁柱单元，适用于分析钢筋混凝土构件，包括扭转效应。该模型基于位移公式，并假设位移较小。截面运动学基于两节点Timoshenko梁的假设，并通过在每个截面引入额外的自由度来增强，以考虑翘曲现象。为此，创建了一个不动点系统，并通过拉格朗日函数和多项式进行插值。考虑到箍筋的影响，在其材料响应之后将控制部分离散化成区域。采用正割刚度公式的修正压缩场理论的基本假设用于表示钢筋混凝土的本构模型。通过与分析解决方案和几个实验测试的比较来验证该模型。模拟包括矩形截面试样在弯曲，剪切和扭转下的各种单调载荷条件。