Nonlinear Creep Analysis of Long-span Prestressed Concrete Bridges

Long-span prestressed concrete (PC) bridges tend to have larger deflection than code-based estimation after several years of operation. Even though creep is usually blamed as one of the most influential time-dependent factors, most current creep models do not give sufficient attention to nonlinear creep behaviour due to higher compressive working stress. In this study, a nonlinear creep model characterized by a stress-sensitive amplification factor is proposed based on experimental data from literature. The model is embedded into the rate-type formula using several user subroutines in Abaqus. Furthermore, a computational framework is established which involves the intertwined effects of concrete creep, shrinkage, and the influence of steel strands relaxation. Finally, a long-span rigid frame box girder bridge is analysed resulting in a good estimation with the in-situ measurement in terms of the long-term deflection.