Review of the Structural Performance of Beams and Beam–Column Joints with Openings

Abstract

The need for openings in RC structures has increased, but their presence significantly affects the performance and strength of the structures. While small openings can be managed with additional reinforcement, dealing with large openings in reinforced or pre-stressed concrete members is challenging due to the lack of technical information and specific guidelines. This research provides an up-to-date overview of RC beam–column joints that incorporate web openings and evaluates appropriate strengthening methods. The research discusses the classification of openings in RC beams, considering factors such as size and shape. Additionally, it examines the failure modes of RC beams in relation to flexural and shear behavior when web openings are present. The research also provides a comprehensive review of various strengthening techniques, outlining their advantages and disadvantages. In conclusion, larger openings in beams result in reduced strength, while increasing loads lead to higher deflection, strain, and cracking until failure. Openings are classified as small or large based on their impact on beam behavior. Multiple smaller openings are preferred over a single large opening when size becomes excessive. Optimal placement is in the middle of the section to ensure adequate concrete coverage for the chords. Sufficient concrete and depth are essential for ultimate compression during bending and effective shear reinforcement.

Keywords

• frame joints
• reinforced concrete
• opening
• cyclic performance
• strengthening