Review of Experimental and FE Parametric Analysis of CFRP-Strengthened Steel-Concrete Composite Beams

Carbon-fiber-reinforced polymer (CFRP) laminates offer a promising solution to enhance the performance of continuous composite beams, particularly in hogging moment zones where tensile stresses are critical. This study extensively reviews the enhancement of flexural capacity and fracture resistance in steel-concrete composite beams (SCCB) reinforced with CFRP at the region of hogging moment. The reviewed literature focuses on experimental programs involving flexural testing in an inverted orientation under four-point loading conditions. This setup replicates the characteristics of continuous SCCBs in hogging moment zones. Experimental results were employed to validate a finite element (FE) model to simulate the nonlinear flexural behavior of both reinforced and plain beams. The literature involving FE model analysis demonstrated excellent agreement with experimental data, confirming its accuracy in predicting numerous parameters' involvement in beam performance. Findings reveal that CFRP laminates significantly enhance beam capacity, with single-layer laminates increasing capacity by 18% and double-layer laminates achieving a 22% improvement. Failure in reinforced beams typically progresses from yielding of steel rebars to rupture of CFRP laminates, followed by diagonal cracking near the supports. For optimal strengthening outcomes, CFRP application is recommended for bridges exhibiting a minimum of 80% composite behavior between the steel members and concrete components. This study highlighted the potential of CFRP laminates as an effective retrofitting technique for steel-concrete composite beams to enhance structural performance and extend service life, particularly in infrastructure subjected to high tensile demands.