In this paper, the results of the numerical analysis of pre-stressed concrete girders made of a high-strength concrete composite with a slab made of normal concrete are presented. A FEM analysis of the construction stage considering the influence of rheological effects on the behaviour of the structure was performed. Results of the analysis are presented in the work and are compared with the results of numerical analysis of the same elements, in which the time-dependent effects are not included. On the basis of these results, appropriate conclusions are proposed.