Finite element study of Rectangular hollow sections (RHS) beam–column connections with web openings

This study investigates the influence of web opening geometry and placement on the structural response of Rectangular Hollow Section (RHS) beam-to-column connections under monotonic loading. A three-dimensional finite element model was developed in ANSYS and validated against published experimental data, showing close agreement in initial stiffness (≈ 2.5 kN/mm), yield load (52–54 kN at 20–22 mm displacement), and ultimate resistance (94–97 kN at approximately 110–115 mm displacement). Parametric analyses were conducted to evaluate rectangular openings (200 × 75–150 mm) and circular openings (Ø75–150 mm) positioned centrally, at the left extremity, and at the right extremity of the beam web. Rectangular openings exhibited similar ultimate load capacities (94–96 kN) to the solid reference specimen but resulted in increased displacement demand, indicating reduced stiffness with increasing opening depth. Circular openings showed smaller variations in both ultimate load (92–96 kN) and displacement (approximately 108–111 mm), with positional effects influencing deformation response. Openings placed near the left extremity exhibited behavior closest to the reference model, while right-extremity openings produced slightly higher deformations. Within the investigated range, the results indicate that web opening geometry and placement primarily affect stiffness and serviceability response rather than ultimate strength. These findings provide insight into the monotonic behavior of RHS beam-to-column connections with web openings and support informed decision-making for service integration in similar configurations.