Research and Application of an Evaluation System for the Flexural Cost Performance Ratio of UHPC Beam Components

Ultra-high performance concrete (UHPC) has demonstrated significant application potential in beam components due to its excellent mechanical properties, durability, and environmental friendliness. However, the high material cost often leads to the misconception that UHPC structures offer low cost-effectiveness, which hinders their widespread engineering adoption. Existing studies mostly focus on optimizing the mechanical properties of UHPC components, but there is a notable lack of systematic evaluation regarding their flexural cost performance ratio. To address this gap, this paper established a comprehensive evaluation system for the flexural cost performance ratio of beam components, aiming to provide theoretical support for the rational design and engineering application of UHPC structures. Firstly, with “performance” and “cost” as the core considerations, an evaluation indicator for flexural cost performance ratio was constructed. Subsequently, the ultimate bending moment was selected to characterize the flexural performance of components, while the material cost per unit length of the pure bending segment was used to represent economic cost. Based on these, a quantifiable cost performance ratio indicator was established. Subsequently, the classic reference method was employed, taking conventional single-reinforcement rectangular beams with appropriate reinforcement as the reference benchmark. The cost performance ratio indicator was then rendered dimensionless throgh the range standardization method. On this basis, integreating probability theory and the K-means clustering algorithm, a grading system for flexural cost performance ratio was established, ensuring both scientific rigor and objectivity. Finally, the evaluation system was applied to comparatively analyze the differences in flexural cost performance ratio between conventional beam members and UHPC beam members. The research results show that the flexural cost performance ratio of reinforced concrete beams is independent of beam width but exhibits a positive correlation with both beam depth and material strength grade. In component design, priority should be given to combinations of higher-strength concrete and highe-strength steel reinforcement, and the substitution of tensile reinforcement with prestressed steel strands can also be considered. Furthermore, if UHPC is simplely used as a direct replacement for ordinary concrete in developing new components, it does not demonstrate an advantage in flexural cost performance ratio. Only through tailored designs that leverage the mechanical characteristics of UHPC and other construction materials can component forms with a high flexural cost performance ratio be achieved.