Abstract
This study investigates the shear performance of ultra-high-performance concrete deep beams (UHPC-DBs) reinforced with hybrid fibers comprising 5D steel fibers and Forta-Ferro (FF) synthetic fibers. UHPC-DBs are widely used in bridges, piles, and transfer girders because of their high load-bearing capacity. Although fiber content strongly influences shear behavior, the contribution of synthetic fibers in hybrid systems remains insufficiently understood. To address this gap, finite element analysis based on the concrete damage plasticity (CDP) model was developed in ABAQUS and validated using experimental results from five previously tested UHPC-DBs with different fiber contents. Load–deflection response, crack patterns, shear capacity, mid-span deflection, fiber stress, and ductility were evaluated. Particle swarm optimization (PSO) was employed to identify the optimal hybrid fiber combination considering both shear performance and cost efficiency. Results indicate that a hybrid system containing 1.0% 5D steel fibers and 0.11% FF synthetic fibers provides the best performance-to-cost ratio, improving shear strength and ductility. Furthermore, UHPC-DBs reinforced with 1.0–2.5% steel fibers combined with 0.55% FF synthetic fibers achieved 92.83–99.19% of the shear capacity of beams reinforced solely with 1.5–3.0% steel fibers. These findings demonstrate the effectiveness of hybrid fiber reinforcement and support updating ACI 318–19 to account for synthetic fiber contributions practice.
Keywords
finite element analysis, hybrid fibers, optimal fiber content, shear performance, Ultra-high-performance concrete
Document Type
Journal Article
Date of Publication
1-1-2026
Article Number
2680372
ISSN
24705314
Volume
11
Issue
3
Publication Title
Journal of Structural Integrity and Maintenance
Publisher
Taylor & Francis
School
School of Engineering
RAS ID
95265
Funding Information
Australian Government Research Training Program Scholarship
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Mirzaaghabeik, H., Shukla, S. K., & Mashaan, N. S. (2026). Numerical investigation of the influence of fiber content on the shear performance of UHPC deep beams reinforced with hybrid steel and synthetic fibers. Journal of Structural Integrity and Maintenance, 11(3), Article 2680372. https://doi.org/10.1080/24705314.2026.2680372