Issue 78

S. M. Khalil et alii, Fracture and Structural Integrity, 78 (2026) 346-366; DOI: 10.3221/IGF-ESIS.78.20

Numerical investigation on web of steel I-beam with closed top flange under patch loading

Sara M. Khalil Institute of Engineering, El-Sherouk Academy, Cairo, Egypt. 2201012@eng.asu.edu.eg Ahmed A. Matloub Faculty of Engineering, Ain Shams University, Cairo, Egypt. ahmed.matloub@eng.asu.edu.eg https://orcid.org/0000-0001-8078-0585 Mona M. Fawzy Institute of Engineering, El-Sherouk Academy, Cairo, Egypt.

mona.fawzy@sha.edu.eg Ahmed H. Yousef Structural Engineering Department, Faculty of Engineering, Ain Shams University, Cairo, Egypt. ahmed_aly@eng.asu.edu.eg

Citation: Khalil, S. M., Matloub, A. A., Fawzy, M. M., Yousef, A. H., Numerical investigation on web of steel I-beam with closed top flange under patch loading, Fracture and Structural Integrity, 78 (2026) 346-366.

A BSTRACT . This paper studies the failure of steel beams' webs and suggests strengthening systems. The study investigates the patch-loading resistance of I-girders with closed top-flange configurations (triangle or rectangle) formed by welding stiffener plates or angles between the web and flange edge. Non linear finite element models are developed and validated to examine the ultimate structural response and failure modes, followed by a parametric study addressing the interaction between stiffener thickness, web thickness, and relative stiffener depth, all under variable patch loading lengths. Compact stiffeners provide a greater increase in girder strength, particularly for thin webs and short patch load lengths, whereas slender stiffeners are less effective. Increasing stiffener depth and thickness enhances load redistribution and delays web deformation. Triangular configurations generally provide higher resistance than rectangular configurations for the same added steel area. EN can calculate the web capacity for the models in the study, but to conservative side. Recommendation is to apply the actual stiffener stiffness in EN avoiding the limitation given in code. Overall, the findings provide practical guidance

Received: 02.07.2026 Accepted: 04.09.2026 Published: 14.09.2026 Issue: 10.2026

Copyright: © 2026 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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