Abstract The beam opening (BO) technique, which involves (1) the creation of a web opening in the beam to weaken its flexural capacity and (2) the fibre-reinforced polymer (FRP) shear strengthening around the opening to avoid shear failure of the beam, was proposed to realize the strong column-weak beam hierarchy in existing reinforced concrete (RC) frames, which were designed using previous codes and thus violated such hierarchy. In the present study, six large-scale T-section beams with a web opening of different sizes and made by different methods (pre-formed and post-cut) were tested to assess the effectiveness of BO technique and the test results are presented. The experimental study shows that the post-cutting method is feasible for making web openings in existing RC beams, the BO technique can effectively reduce the flexural capacity of the beam to the desired value if the size of web opening is appropriate, and the FRP strengthening can well compensate the loss of shear capacity and ductility of the beam caused by the creation of web opening. The present study provides a basis for the safe use of BO technique to achieve the strong column-weak beam hierarchy in existing RC frames.

中文翻译：

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具有纤维增强聚合物 (FRP) 增强腹板开口的 RC 梁的行为

摘要 梁开口 (BO) 技术包括 (1) 在梁中创建腹板开口以削弱其抗弯能力和 (2) 开口周围的纤维增强聚合物 (FRP) 剪切加强以避免梁的剪切破坏。该梁被提议用于在现有钢筋混凝土 (RC) 框架中实现强柱弱梁层次结构，这些框架是使用以前的代码设计的，因此违反了这种层次结构。在本研究中，测试了六个具有不同尺寸和不同方法（预成型和后切割）的腹板开口的大型 T 型梁，以评估 BO 技术的有效性，并展示了测试结果。试验研究表明，后切法在现有钢筋混凝土梁上开腹是可行的，如果腹板开孔尺寸合适，BO技术可以有效地将梁的抗弯承载力降低到所需值，而FRP加固可以很好地补偿因腹板开孔产生而造成的梁抗剪承载力和延性的损失。本研究为安全使用 BO 技术在现有 RC 框架中实现强柱弱梁层次结构提供了基础。