This article presents a refined version of the Combined Action Softened Truss Model (CA-STM) with efficient solution procedure to analyze reinforced concrete (RC) members under torsion combined with bending. To refine the model, a set of appropriate smeared stress–strain relationships for concrete and steel bars, to account for the softening and stiffening effects, are implemented. For solid sections, an alternative criterion to fix the maximum thickness for the panels constituting the walls of the equivalent hollow section is also considered. In addition, a simpler criterion is used to compute the equivalent longitudinal reinforcement for each panel. Instead of using the original algorithm to solve the CA-STM, which is based on a classical trial and error solution technique, an alternative one which lead to a more efficient solution procedure with higher numerical stability is implemented. These refinements allow the model to predict efficiently the response of RC members under torsion combined with bending. The results obtained from the refined efficient CA-STM procedure are compared with several experimental results found in the literature, where good agreement is observed.

本文介绍了组合作用软化桁架模型（CA-STM）的精简版本，它具有有效的解决方法，可以分析在扭转和弯曲作用下的钢筋混凝土（RC）构件。为了完善模型，对混凝土和钢筋设置了一组适当的拖尾应力-应变关系，以解决软化和加劲的问题。对于实心型材，还应考虑为构成等效空心型材的壁的面板固定最大厚度的替代标准。另外，使用更简单的标准来计算每个面板的等效纵向钢筋。而不是使用基于经典试验和错误解决技术的原始算法来求解CA-STM，实现了一种替代方案，该方案导致了具有更高数值稳定性的更有效的求解过程。这些改进使模型可以有效地预测钢筋混凝土构件在扭转和弯曲作用下的响应。从改进的高效CA-STM程序中获得的结果与文献中发现的几个实验结果进行了比较，其中观察到很好的一致性。