Model Uncertainty in European UHPC Standards: Insights from SIA-2052 and NF P18-710 Flexure Models

This study explores the assessment of model uncertainty within European Ultra-High-Performance Concrete (UHPC) standards, focusing particularly on the flexure models outlined in Swiss SIA-2052 and French NF P18-710. Model uncertainty is calibrated by comparing predictions of these models against a comprehensive test database consisting of 211 UHPC beams reported to fail in flexure. Additionally, the characteristics of model uncertainty, including mean, coefficient of variation, and probability distributions, are discussed. The study also explores regression and correlation analysis between model uncertainty and basic variables. Finally, the implications of these findings for partial factor method verifications are explored. Limitations of this study and scope of application of the obtained results are discussed and needs for further research are outlined. This analysis contributes to the ongoing discourse surrounding UHPC standards, offering valuable insights for improving reliability analysis of new structures made of novel UHPC materials.