Optimizing flexural strength of reinforced concrete beams: A comparative exploration of innovative strengthening techniques using experimental and numerical approaches

This study examines different methods to enhance the flexural strength of reinforced concrete (RC) beams through experimental and numerical analyses. Both experimental and numerical analyses were conducted to assess the effectiveness of these techniques. The experimental program involved ten full-scale RC beams, each measuring 150 mm × 250 mm × 2000 mm. The first beam served as a control with no strengthening, while the remaining nine were reinforced using different techniques. The second beam (B2-HSC) was strengthened with high-strength concrete (HSC) at the bottom; the bottom cover was removed to a depth of 50 mm, and HSC was cast along the beam's length. The third beam (B3-UHSC) followed the same process, but Ultra High-Strength concrete (UHSC) was used. The fourth beam (B4-C.P) was reinforced with a 150 mm × 1 mm steel plate attached to its bottom surface using end anchorage bolts. The fifth beam (B5-S.P) was similarly strengthened but with a stainless steel plate instead. The sixth beam (B6-S.W.M) was reinforced by bonding steel wire meshes around the central flexural span of the beam, while the seventh beam (B7-S.W.M) had steel wire meshes bonded along the entire bottom length. The eighth beam (B8-GFRP) was strengthened with two 10 mm GFRP bars encased in a concrete jacket matching the strength of the control beam. The ninth beam (B9-S.B.T) was reinforced by bonding two steel truss bars to its sides at the middle third, and the tenth beam (B10-GFRP.T) followed the same method but replaced the steel truss bars with GFRP sheets. The results demonstrated that all strengthened beams had significantly higher load-carrying capacities compared to the control. Beams B4-C.P and B5-S.P exceeded the control beam's failure load by approximately 141% and 97%, respectively, with the steel plate proving more effective than the stainless steel plate, despite the latter's superior corrosion resistance. The failure loads of the strengthened beam B6-S.W.M and B7-S.W.B are greater than the control beam B1-Control by about 9% and 40%, respectively. The failure loads of the strengthened beam B9-S.B.T and B10-GFRP.T are greater than the control beam B1-Control by about 15% and 9%, respectively. Also, the results showed that the ductility factor of beams B3-UHSC, B4-C.P, B5-S.P, B6-S.W.M, B9-S.P.T, and B10-GFRP.T is greater than the control beam by about 70%, 76%, 129%, 347%, 12%, and 58%, respectively. A finite-element model, developed using ABAQUS, validated the experimental findings, showing strong alignment between numerical and experimental results. The study was further expanded through parametric analysis.