Journal of Structural and Construction Engineering

Journal of Structural and Construction Engineering

Effect of openings and GFRP strengthening on the shear behavior of hollow reinforced concrete deep beams: Experimental study and finite element modeling

Document Type : Original Article

Authors
1 Ph.D. candidate, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran
2 Associate Professor, Faculty of Engineering, BU-ALI SINA University, Hamedan, Iran
10.22065/jsce.2026.566962.3901
Abstract
Hollowing deep beams reduces self-weight and material consumption and web openings are highly efficient for routing mechanical and electrical services; however, the combined effect of hollowing and transverse web openings on shear behavior has rarely been examined. Accordingly, a controlled four-point-bending program was conducted on a set of specimens. In addition to recording first-cracking and ultimate loads, effective stiffness before and after cracking was extracted, and two quantitative indices were defined to capture the opening effect and the strengthening effect for direct comparison and rapid decision-making. Hollowing reduced the first-cracking load by about 30% and the ultimate load by about 10%. Adding an opening off the load path, relative to the hollow beam, produced further reductions of about 34% (first-cracking) and 7% (ultimate), whereas placing the opening on the load path was more critical, causing reductions of about 23% and 29%. From a stiffness perspective, off-path drops before cracking and at peak were about 11% and 10%, respectively, whereas on-path drops reached about 23% and 38%. Strengthening with glass-fiber–reinforced polymer showed a restorative response: for the off-path case, the first-cracking load increased by about 43% and the ultimate load by about 8%; for the on-path case, the first-cracking load increased by about 82% and the ultimate load by about 15%, although the ultimate capacity still remained about 18% lower than the hollow reference.
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Articles in Press, Accepted Manuscript
Available Online from 17 July 2026

  • Receive Date 27 December 2025
  • Revise Date 21 June 2026
  • Accept Date 17 July 2026