Due to the increase in traffic volume, load level, and service life of existing bridges, the bending bearing capacity of reinforced concrete beams (hereinafter referred to as RC beams) has decreased, leading to safety issues. In order to solve the problem of insufficient flexural bearing capacity of RC beams, this article adopts the method of ultra-high performance concrete (UHPC) flexural strengthening RC beams, establishes a finite element model of UHPC-RC reinforcement system, and conducts stress analysis with reinforcement thickness, reinforcement range, reinforcement form, and reinforcement height as parameters to determine the optimal scheme of the reinforcement system. Based on the calculation results, a theoretical formula for the maximum principal stress and maximum deflection of the reinforcement system is proposed. To verify the feasibility of the plan, a reinforcement design was carried out on an existing beam, and it was found that the bending bearing capacity of the RC beam increased by 21%; the high tensile strength of UHPC and the addition of steel fibers have a good limiting effect on cracks; The steel plate of the reinforcement system can be used as a template, reducing construction costs and having good economy.

In recent years, bridge safety accidents caused by insufficient shear bearing capacity of bridges have attracted increasing attention. The main causes include internal factors such as insufficient bridge section and deterioration of steel bars, as well as external factors, for example, vehicle load surge and improper maintenance. To address this issue to some degree, this article adopts the method of strengthening RC beams with ultra-high performance concrete (UHPC) and conducts parameter analysis using finite element method, taking into consideration the influence of four parameters: reinforcement material, reinforcement thickness, reinforcement length, and reinforcement form on the shear strengthening characteristics of RC rectangular beams. After obtaining the optimal reinforcement plan through parameter analysis, the author applied the research results to an existing bridge with insufficient shear strength. It then turned out that the shear bearing capacity of the reinforced bridge’s inclined section increased by approximately 27.1%. Simple and fast in construction, this reinforcement method is one of the methods that is effective to increase cross-section reinforcement; besides, it features good economic characteristics and applicability.