PSI - Issue 81

Mykola Pidgurskyi et al. / Procedia Structural Integrity 81 (2026) 439–446

446

The structural efficiency was evaluated based on the maximum value of the efficiency criterion. For horizontal beams with haunches and stiffening rings, the criterion value equals 1.982; for double-pitched beams with haunches and stiffening rings, it equals 1.895; and for arched beams without haunches and stiffening rings, it reaches 2.569. Therefore, the arched perforated beam can be considered the most efficient configuration among all the investigated variants, both with and without reinforcement. Conclusions The finite element analysis performed in this study demonstrated that the highest equivalent stresses in perforated steel I beams occur at the near-support openings. The local stress concentrations in these zones may exceed the yield strength of the steel, creating a risk of plastic deformation and cracking within the web. A comparative assessment of horizontal, double-pitched and arched perforated beams showed that introducing an inclination induced thrust leads to a redistribution of internal forces and reduces the equivalent stresses around the openings. The maximum stresses in the double-pitched beam are 1.52 times lower than those in the horizontal beam, whereas the arched beam exhibits a reduction by a factor of 2.86. It was found that, due to its curved geometry, the arched perforated beam experiences the lowest equivalent stresses around the openings without the use of any reinforcement methods, which highlights its superior structural efficiency compared to the other investigated beam types. However, the fabrication of such members is more technologically demanding and labor-intensive. The use of haunches in the eaves and apex joints decreases the maximum equivalent stresses around the perforated openings by a factor of 1.27 for horizontal beams and 1.37 for double-pitched beams. At the same time, the overall weight of the beams increases on average by a factor of 1.22. For arched beams, the use of haunches does not provide a meaningful reduction in stresses and is therefore recommended solely for structural purposes. Strengthening the perforation openings with circular stiffening rings effectively reduces local stresses: by a factor of 2.26 for horizontal beams without haunches and by 2.87 for those with haunches; and by 1.58 for double-pitched beams without haunches and 1.70 for those with haunches. After reinforcement, the stresses in all strengthened models remain below the steel yield limit, ensuring the structural reliability and safe performance of the elements throughout their service life. References Abbas, M., Al - Thabhawee, H., 2022. Experimental study of composite concrete cellular steel beams. 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