Multiscale modelling of the long-term performance of prestressed concrete structures – Case studies on T-Girder beams

Abstract

It is well known that the long-term performance of prestressed concrete structures, i.e. the evolution of strains and stresses over time, is mainly dominated by the coupled effect of creep and shrinkage of concrete combined with the relaxation occurring in the prestressing tendons. Studies focusing on the long-term performance of real structures have been growing mainly in the last decade focusing on more efficient procedures for the design of prestressed concrete structures.This work introduces a novel bottom-up approach for the long-term analysis of T-girder prestressed beams. Two case studies are considered to support this work: (i) a small-scale beam and (ii) a full-scale double T-girder. A thorough discussion is made based on the quantification of displacements, strains and stresses in both concrete and tendons.It is found that keeping the material-related properties as invariant in the modelling, the attainment of the Serviceability Limit States is dependent on the finite element type selected to model the long-term behaviour of the structure.