Flexural Behavior of Reinforced Concrete Beams with Utility Facilities in the Section Area

Reinforced concrete beams that incorporate utility facilities are designed to enhance efficiency by reducing the overall volume of concrete required and providing a functional space for utility storage. The main objective of this study is to rigorously evaluate whether the load-bearing capacity of these specially designed beams is comparable to that of traditional solid-reinforced concrete beams. To achieve this, three beams were subjected to rigorous bending tests: one set of solid reinforced concrete beams and two sets that included utility facilities, utilizing 3-inch and 4-inch PVC pipes, respectively. The experimental results revealed that the bending capacity of each beam was primarily influenced by the allowable deflection, which was capped at 1.25 mm. The recorded bending capacities were as follows: 138.13 kN for the solid beams, 120.8 kN for the beams with 3-inch pipes, and 106.90 kN for those fitted with 4-inch pipes. These findings highlight a significant observation: the stiffness of the beams containing utility facilities—regardless of the pipe size—was notably lower than the solid reinforced concrete beams. However, these utility-equipped beams exhibited more excellent ductility, indicating they could undergo more deformation before failure. Additionally, the analysis of the relationship between load and deflection mirrored these trends, underscoring that the tensile strength of the reinforcement bars (rebar) plays a critical role in determining the bending capacity of the beams. This comprehensive evaluation provides valuable insights into the structural performance of reinforced concrete beams equipped with utility features, laying the groundwork for future construction practices prioritizing functionality and material efficiency.