A simple yet effective constitutive model-referred to as the “Fixed Strut Angle Model” (FSAM)-is presented in this paper for simulating the nonlinear axial/shear behavior of reinforced concrete membrane (panel) elements subjected to generalized and reversed cyclic loading conditions. In the formulation of the FSAM, normal stresses in cracked concrete are calculated along fixed crack (strut) directions. Shear stresses developing along crack surfaces, which are calculated using a simple friction-based constitutive relationship, are superimposed with the concrete stresses along the struts, for obtaining the total stress field in concrete. Model predictions were compared with panel tests results available in the literature, at various global and local response levels. The model was demonstrated to reasonably capture the overall response characteristics of reinforced concrete panels, including hysteretic shear stress vs. strain behavior, shear stress capacity, hysteretic shear stiffness attributes, ductility, pinching behavior, governing failure mode, principal strain and stress directions, and local deformations.

中文翻译：

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钢筋混凝土板单元的滞回本构模型

本文提出了一种简单而有效的本构模型——称为“固定支柱角度模型”(FSAM)——用于模拟钢筋混凝土膜（面板）单元在广义和反向循环载荷条件下的非线性轴/剪性能. 在 FSAM 的公式中，裂缝混凝土中的法向应力是沿固定裂缝（支柱）方向计算的。沿裂缝表面产生的剪应力，使用简单的基于摩擦的本构关系计算，与沿支柱的混凝土应力叠加，以获得混凝土中的总应力场。在各种全局和局部响应水平下，将模型预测与文献中可用的小组测试结果进行比较。