Title:
Ultimate Flexure Strength Evaluation of Reinforced-Concrete Beams Retrofitted with CFRP (Prepublished)
Author(s):
Jorge L. Bazan and Victor I. Fernandez-Davila
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
CFRP flexural strengthening, probable moment strength, RC beam, shear capacity design, ultimate flexure strength
DOI:
10.14359/51749171
Date:
9/11/2025
Abstract:
This study investigates the ultimate flexural strength (UFS) of reinforced concrete beams strengthened with CFRP (RCB-SCFRP), focusing on the identification and quantification of flexural overstrength concerning the nominal flexural strength (NFS) as defined by ACI 440.2R. A total of 106 full-scale specimens tested were carefully selected from previous research, varying in concrete strength, reinforcement configurations, and CFRP materials from multiple manufacturers. Results show that ACI 440.2R provisions accurately and conservatively estimate the flexural capacity of CFRP-strengthened beams. Including CFRP transverse reinforcement (TR) resulted in a slight increase in UFS. The type of strengthening, whether preloaded and repaired or strengthened, had little effect on the UFS/NFS ratio. Steel reinforcement ratio (SRR) significantly influenced overstrength, with higher UFS/NFS ratios observed between 0.70% and 1.00% SRR. CFRP axial rigidity notably affected overstrength, with optimal performance between 0.10 and 0.50 GPa·mm. Deflection ductility was mainly affected by the rigidity of CFRP, with a 13% increase noted due to CFRP TR. A log-normal model was developed to estimate UFS for RCB-SCFRP beams based on experimental data and ACI 440.2R guidelines.