Fatigue Performance of One-Way RC Slabs Strengthened in Flexure with NSM Steel and FRP Bars

Yasser Rifat Tawfic; Yehia Abdelazim Hassanean; Moamen Adel El Hamdy; Ahmed Attia Mahmoud Drar

doi:10.2478/cee-2026-0056

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Fatigue Performance of One-Way RC Slabs Strengthened in Flexure with NSM Steel and FRP Bars

Civil and Environmental Engineering

Volume 22 (2026): Issue 2 (June 2026)

By: Yasser Rifat Tawfic, Yehia Abdelazim Hassanean, Moamen Adel El Hamdy and Ahmed Attia Mahmoud Drar

Open Access

|Jun 2026

Abstract

Many reinforced concrete (RC) members, such as bridge slabs, are periodically subjected to repeated loads and therefore require strengthening to extend their service life. The near-surface mounted (NSM) technique has recently emerged as one of the most effective methods for flexural strengthening. This study investigates the fatigue behaviour and flexural load-carrying capacity of one-way RC slabs strengthened with NSM steel, CFRP, GFRP, and BFRP bars. A total of ten slabs were tested: five under static loading and five under cyclic loading. The fatigue group was subjected to one million cycles at 50% of the ultimate static load of their respective controls, followed by static loading to failure. Performance parameters examined included crack development, failure modes, ultimate load, mid-span deflection, residual strength, ductility, energy absorption, and deformability. The results demonstrated that NSM strengthening significantly improved slab performance. The slabs were strengthened using carbon fibre-reinforced polymer (CFRP), glass fibre-reinforced polymer (GFRP), basalt fibre-reinforced polymer (BFRP), and steel bars, designated as FCR, FGR, FBR, and SR, respectively. The maximum load-carrying capacities increased by 122.5%, 49.1%, 61.35%, and 21.77%, respectively, compared to their corresponding control slabs. Residual bearing capacity also improved, with CFRP- and BFRP-strengthened slabs (FCR and FBR) achieving 11.26% and 8.17% gains over their static counterparts. These findings confirm the effectiveness of the NSM technique in enhancing fatigue resistance and post-fatigue serviceability of RC slabs, with CFRP bars providing the greatest strength improvement among FRP options, while steel bars offered a balanced combination of strength and ductility.

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Articles in this issue

DOI: https://doi.org/10.2478/cee-2026-0056 | Journal eISSN: 2199-6512 | Journal ISSN: 1336-5835

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Language: English

Page range: 851 - 868

Submitted on: Oct 2, 2025

Accepted on: Oct 17, 2025

Published on: Jun 19, 2026

Published by: University of Žilina

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

Fatigue behaviour,

Flexural strengthening,

One-way RC slabs,

NSM technique,

FRP bars

Related subjects:

Business and economics,

Business management,

Industries,

Environmental management

© 2026 Yasser Rifat Tawfic, Yehia Abdelazim Hassanean, Moamen Adel El Hamdy, Ahmed Attia Mahmoud Drar, published by University of Žilina
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 22 (2026): Issue 2 (June 2026)