Abstract Shear strength of reinforced concrete beams has been extensively studied by many experimental campaigns conducted on simply supported beams. This situation has led to implement empirical design formulations in codes that cannot be representative of other real structures, such as continuous beams. These structures are characterised by the potential development of plastic hinges in areas of maximum shear and by the existence of an inflection point in the shear span. However, very few experimental studies on them have been conducted. In this paper, the shear strength of cantilever and continuous beams with different shear reinforcement ratios is analysed based on the test results of an experimental programme involving 15 beams. Nine beams of 9.00 m and six of 7.00 m with rectangular cross-sections were tested under different load and support conditions, which gave rise to 30 different shear tests (two tests per beam). Three different series were considered according to the shear reinforcement ratio (0%, 0.13% and 0.20%). Apart from traditional instrumentation, such as strain gauges and displacement transducers, Digital Image Correlation was employed to provide accurate displacement measurements. The results showed that the shear strength provided by concrete (different shear-transfer actions from shear reinforcement) decreased as bending rotation increased within both the elastic and plastic ranges of rotations developed in continuous beams. Moreover, this shear strength component was reduced for increasing shear reinforcement ratios. Shear slenderness was redefined for continuous beams that failed in shear after yielding of the tensile reinforcement and redistributing internal forces. The code formulation provided by ACI 318-19, Eurocode 2 and Model Code 2010 was checked against the experimental results, which showed that the iterative formulation that contemplates the M-V interaction considerably improved shear strength predictions from simple formulations.

中文翻译：

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钢筋混凝土连续梁抗剪强度试验研究

摘要 钢筋混凝土梁的抗剪强度已经通过在简支梁上进行的许多实验活动进行了广泛的研究。这种情况导致在无法代表其他真实结构（例如连续梁）的代码中实施经验设计公式。这些结构的特点是在最大剪切区域可能出现塑性铰，并且在剪切跨度中存在拐点。然而，对它们进行的实验研究很少。在本文中，基于一个涉及15根梁的实验程序的测试结果，分析了具有不同抗剪配筋率的悬臂梁和连续梁的抗剪强度。九根 9.00 m 的梁和六根 7 的梁。00 m 矩形截面在不同的载荷和支撑条件下进行了测试，产生了 30 种不同的剪切测试（每梁两个测试）。根据抗剪配筋率（0%、0.13%和0.20%）考虑了三个不同的系列。除了应变计和位移传感器等传统仪器外，还采用数字图像相关来提供准确的位移测量。结果表明，混凝土提供的剪切强度（来自抗剪钢筋的不同剪切传递作用）随着弯曲旋转在连续梁中产生的弹性和塑性旋转范围内增加而降低。此外，该剪切强度分量随着剪切增强比的增加而降低。对于在受拉钢筋屈服并重新分配内力后在剪切中失败的连续梁，剪切细长被重新定义。ACI 318-19、Eurocode 2 和 Model Code 2010 提供的规范公式与实验结果进行了比较，结果表明考虑 MV 相互作用的迭代公式大大改进了简单公式的剪切强度预测。