Methods for Calculating the Concrete Core of Looped Reinforcement Joints Without Reinforcement

The article presents a comparative analysis of four methods for calculating the concrete core of looped reinforcement joints without additional reinforcement, including the NIIES Hydroproject method based on Mohr's strength theory, the strut-and-tie model proposed by Singaporean researchers, the BS EN 1992 (Eurocode 2) methodology, and a modified method developed by the authors. The study primarily focuses on analytical techniques to assess the load-bearing capacity of loop joints under various operational conditions, highlighting the distinct characteristics of each approach. The NIIES Hydroproject method, while structurally comprehensive, places a strong emphasis on the strength of the concrete core, which can influence design safety. In contrast, the Singaporean strut-and-tie model provides an alternative analytical perspective but may not always align with practical applications. The BS EN 1992 approach integrates contemporary structural principles and offers a balanced assessment of loop joints, though it necessitates additional reinforcement considerations. The authors’ modified method enhances existing analytical frameworks by incorporating stress adjustments, aligning well with experimental observations while maintaining computational efficiency. A comparative assessment of the four methods is conducted using experimental data for a monolithic beam with loop joints, confirming that the BS EN 1992 methodology and the proposed modified method provide the most reliable results for structural design. The study highlights the importance of accurate and efficient calculation models in ensuring the structural integrity of loop joints in reinforced concrete construction.