Failure behavior and probabilistic safety assessment of containment structure under internal pressure considering time-varying prestress loss

• Published in: Engineering structures 2024-11, Vol.319, p.118884, Article 118884
• Main Authors: Li, Xinbo, Wu, Xingyi, Gong, Jinxin
• Format: Article
• Language: English
• Subjects: Concrete creep; Containment structure; Failure behavior; Internal pressure; Kelvin chain model; Probabilistic safety assessment; Time-varying prestress loss
• ISSN: 0141-0296
• DOI: 10.1016/j.engstruct.2024.118884

This paper adopts a refined method to calculate the prestress loss of containment and evaluates the impact of time-varying effects on the mechanical properties and safety of containment under accident pressure. Firstly, a new method for converting the commonly used creep model into the Kelvin chain creep model is proposed, and rate-type constitutive relationships considering time-varying factors are established. Utilizing the developed subroutine scripts, these constitutive relationships are incorporated into the ABAQUS platform. Subsequently, the prestress losses of containment at different service times are calculated. Finally, the failure behavior and the probabilistic performance of containment under prestress loss and internal pressure conditions are systematically discussed. Results show that the proposed method exhibits high applicability, and the fitted creep compliance function based on the Kelvin chain model agrees well with the original creep compliance function. For the investigated containment, the time-varying prestress loss is most pronounced in the horizontal tendons near penetrations. Under design pressure, the containment remains elastic for all investigated prestress loss conditions, but the structural deformation, steel liner strains, and principal tensile stresses in concrete increase with the increase in time-varying prestress losses. At the limit state, greater time-varying prestress loss makes the containment more prone to functional failure at lower internal pressures. The time-varying prestress loss has a significant impact on the fragility and reliability of the penetrations in containment, while its impact on regular segments is relatively small. ●A refined method is used to predict the prestress loss of containments.●A new method for converting the Kelvin creep model is proposed.●Rate-type constitutive relationships considering time-varying factors are established.●Time-varying effect on the failure behavior and probabilistic performance of containments under accident pressure is evaluated.