Deep beams with shear span‐to‐depth ratios a/d ≤ 2.5 are used to resist large shear forces due to their ability to develop direct strut action. To further enhance the shear strength and crack control of such members, researchers have studied the use of fiber‐reinforced concrete (FRC). However, while this solution is promising, there is a need for rational mechanical models capable of predicting the shear strength of FRC deep beams in a sufficiently simple manner. This paper proposes such a model based on first principles: kinematics, equilibrium, and constitutive relationships. The proposed model simplifies an earlier two‐parameter kinematic theory (2PKT) for the complete shear behavior of FRC deep beams, to predict the shear strength and components of shear resistance in a straightforward manner. The new simplified method is validated by comparing the predicted results to 22 tests from the literature, as well as to FEM and 2PKT predictions. It is shown that the proposed simplified kinematic approach predicts well the shear strength with an average experimental‐to‐predicted shear strength ratio of 1.12 and a coefficient of variation of 12.9%. Furthermore, the model is used to discuss the effect of shear span‐to‐depth ratio and fiber volumetric ratio on the shear strength of FRC deep beams.

中文翻译：

---

纤维增强混凝土深梁抗剪强度的简化运动学方法

剪切跨度与深度之比为a / d的深梁≤2.5用于抵抗大的剪切力，因为它们具有产生直接支撑作用的能力。为了进一步增强此类构件的抗剪强度和裂缝控制能力，研究人员研究了纤维增强混凝土（FRC）的使用。然而，尽管该解决方案是有前途的，但是需要能够以足够简单的方式预测FRC深梁的抗剪强度的合理的力学模型。本文提出了基于第一原理的这种模型：运动学，平衡和本构关系。所提出的模型简化了FRC深梁完整剪切特性的早期两参数运动学理论（2PKT），从而以直接的方式预测了剪切强度和抗剪强度分量。通过将预测结果与文献中的22个测试以及FEM和2PKT预测进行比较，验证了新的简化方法。结果表明，所提出的简化的运动学方法能够很好地预测剪切强度，实验与预测的平均剪切强度之比为1.12，变异系数为12.9％。此外，该模型还用于讨论剪切跨度比和纤维体积比对FRC深梁抗剪强度的影响。