Accounting for the effect of creep and shrinkage on the stress state of concrete structures of cable-stayed bridges in Myanmar

Abstract

The article considers the finite element analysis of the influence of time-dependent processes (creep and shrinkage) of concrete on the structures of a concrete cable-stayed bridge according to Russian, European and American standards. For numerical calculation, the Midas/Civil software was used, which allowed us to take into account elastic short-term deformation and creep deformation, as well as changes in the strength of concrete over time. Long-term deformations in concrete elements could be 1.5~3.0 times higher than elastic deformations and were observed in the first few months, and most of them occurred within five years. The object of research was a cable-stayed bridge with a reinforced concrete beam with a box girder. Three calculation models were used to model concrete shrinkage and creep: according to Russian, European and American standards. The results of the study showed significant discrepancies between foreign and Russian standards for accounting for long-term processes in concrete structures of cable-stayed bridges. Creep and shrinkage processes led to increased displacements in the box girder and pylon. Moreover, with an increase in the humidity of the environment, the deflection of the girder decreased, and the displacement of the pylon slightly increased. The cable-forced was reduced by the shrinkage and creep of the concrete. It was found that the loss of cable forces decreased with increasing humidity of the environment.