<b>Nonlinear Modeling of Concrete Beam with Opening in Flexural Region</b>

The use of openings in reinforced concrete beams is a common practice to accommodate utility ducts and pipes necessary for essential services like water supply, electricity, telecommunications, and computer networks. In existing buildings, drilling openings in beams may be required for serviceability; however, the ACI Code lacks clear criteria regarding deformation and cracking in this context and does not consider the nonlinear material behavior that occurs after cracking. To investigate these issues, a study utilized the nonlinear finite element modeling to analyze the behavior of reinforced concrete beams with such openings. The flexural behavior of steel-reinforced concrete beams, both with a single opening in the flexural zone and without openings, was analyzed using 2D Diana Finite Element Analysis. The Diana beam modeling utilizes height-to-width ratios of 30 cm by 20 cm and 30 cm by 30 cm. Furthermore, it includes openings of sizes 10 cm and 15 cm located in the flexural zone. The study examined initial cracking load, load-deflection curves, ultimate load, stress distribution, crack patterns, and failure modes. This comprehensive analysis offers valuable insights into the impact of openings on the structural performance of reinforced concrete beams under flexural loads. This analysis confirms that beams with openings display larger crack widths and lower load-bearing capacity compared to control beams. This indicates a reduced structural integrity under identical loading conditions and highlights the significant impact of geometric modifications on beam performance.