A Parametric Study on the Behavior of CFRP-Strengthened Reinforced Concrete Deep Beams with Cut Circular Web Openings in Shear Spans

Web openings are created in reinforced concrete deep beams for various purposes. The CFRP strengthening technology is commonly employed to mitigate the adverse consequences of these openings. The impact of openings generated in areas of stirrupless or by arranging the stirrups at the bottom and top chords of the opening in a closed configuration has been examined in numerous studies. However, in reality, stirrup damage frequently occurs when openings are made due to the high number of stirrups employed in deep beams. In this study, three specimens tested in a previous experimental study were modeled via ABAQUS, and the results obtained were validated by comparing them with the experimental results. To create openings of varying sizes in the elements, the reinforcements were cut, and these beams were strengthened with CFRP laminates, followed by a parametric study. The findings indicated a 56% reduction in the load-carrying capacity of the unstrengthened beam (h = 500 mm) featuring a 300 mm diameter opening, alongside an 87% decrease in energy dissipation. Although the diameter of the opening, which was formed by cutting the stirrups, is less than one-third of the beam's height, the application of 1.8 mm thick laminates resulted in only limited improvement.