Multi-Physics and Multi-Scale Analysis of Prestress Loss and Deflection in Large-Scale Structures Under the Influence of Environmental Humidity

Prestressed structures, serving as key components in bridge and tunnel construction, frequently operate in high or variable humidity environments. To investigate the long-term deformation and prestress loss of prestressed beams under varying environmental humidities, this study employed the DuCOM-COM3 multi-physis and multi-scale finite element program to analyze prestressed concrete structures across different humidity levels and compared these findings with experimental results. The findings indicated that concrete beam prestress loss was influenced by environmental humidity; higher humidity reduced long-term deformation, thereby mitigating prestress loss and long-term deflection in these structures. This suggests that constitutive models based on multi-scale micro-pore structures could capture the micro-deformations within pore structures, enabling the determination of concrete structures’ mechanical properties through computations of micro-behavior and moisture transport within the concrete. Comparative experiments and calculations demonstrated that multi-field and multi-scale analysis of concrete structures could assess the effects of changing environments on the long-term performance of prestressed concrete structures. Through analyzing the mechanism of multi-physics and multi-scale analysis of moisture-heat-stress coupling, the paper simulated the prestress loss and long-term deflection of prestressed concrete beams under environmental humidity conditions of 40%, 60%, and 80%. The relations between environmental humidity and the shrinkage and creep, the long-term deformation, and the prestress loss were obtained.