Study on the Ultimate Bearing Capacity of Ultra-High Performance Concrete Walls Under Single-Sided Thermal Load and Eccentric Compression

To develop an ultra-high performance concrete (UHPC) wall structure suitable for nuclear power plant applications, this study establishes a finite element model to evaluate the ultimate bearing capacity of UHPC walls under eccentric compression with single-sided thermal loading during accident conditions. The accuracy and reliability of the finite element analysis (FEA) method were rigorously validated by simulating and replicating experimental results using the same modeling approach adopted in this study. Based on the validated model, the influence of single-sided thermal loading on the ultimate bearing capacity of UHPC walls under nuclear power plant accident conditions was thoroughly investigated. Key parameters—including the reinforcement ratio, steel fiber volume fraction, temperature, eccentricity, and concrete strength grade—were systematically analyzed to determine their effects on the ultimate bearing capacity of UHPC wall specimens. The results demonstrate that the reinforcement ratio, steel fiber volume fraction, temperature, eccentricity, and concrete strength grade significantly affect the degradation rate of the ultimate load of UHPC walls as the temperature increases. Additionally, this paper proposes a calculation method for the normal section bearing capacity of rectangular cross-sections in UHPC large eccentric compression members under single-sided thermal loads. These findings provide theoretical support and scientific evidence for the design of new UHPC structural specimens in nuclear power plants.