Finite Element Modeling of Reinforced Concrete (RC) Beams Strengthened with Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC)

Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) is an increasingly recognized material for structural rehabilitation and flexural strengthening of reinforced concrete (RC) beams. While numerous experimental studies have been conducted to investigate its structural efficiency, less focus has been accorded to advanced finite element (FE) modeling and comprehensive parametric studies leading to strengthening optimization. To address this gap, this study presents a validated FE parametric investigation of three UHPFRC strengthening configurations: three-sided jackets, two-sided lateral plates and bottom plates. Thicknesses varied from 10 to 70 mm, comprising a total of 21 parametric models in addition to those used for experimental validation. The findings demonstrate that UHPFRC layers significantly alter the load-deflection response, yielding substantial improvements in both initial stiffness and ultimate load-carrying capacity. The configurations effectively delay crack propagation and enhance energy dissipated prior to failure. Among the configurations, three-sided jacketing provides superior performance due to concrete confinement and increased cross-sectional area of the beam. Based on these insights, it is recommended to prioritize the three-sided UHPFRC jacket configuration with optimized thickness as the most efficient option for the structural strengthening and load-capacity optimization of flexure-deficient RC beams.