Design Requirements for RC Beams With Multiple Transverse Circular Openings Near Column Faces: Experimental and FEA Approaches

The increasing complexity of modern construction necessitates multiple transverse openings in reinforced concrete (RC) beams to accommodate utility pipelines, often requiring these openings to be placed closer to the column face. While prior studies have primarily focused on beams with a single opening, this work investigates the minimum allowable spacing between two transverse circular openings and their proximity to the column face. A combined numerical and experimental approach is adopted. Finite element analysis (FEA) is employed to simulate stress distribution, deformation behavior, and failure mechanisms under various opening configurations, based on reinforcement guidelines from previous research. The FEA models are validated against existing experimental data to ensure accuracy. Additionally, two T‐shaped RC beam specimens with transverse circular openings are tested to assess the minimum clear distance from the opening to the column face. A modified plastic truss model is used to predict shear strength in beams exhibiting shear failure near openings, and its predictions are compared with both FEA results and experimental outcomes. Based on these findings, this work proposes practical design recommendations for the placement of transverse circular openings near the ends of RC beams.