Lateral bracings for the stabilization of girders that are at risk of lateral-torsional buckling are subjected to stability loads besides possible outer loads. The stability loads are the result of effects of forces at the girder with geometrical imperfections in the deformed state. In this article a detailed investigation is carried out for the most important case of girder with loading and lateral supports at the upper chord to analyse the approach of the DIN 1052 (08/04) on validity and efficiency. The complexity of the 2 nd order flexural torsion problem forces to use a numeric solution method. Unlike numerous contributions of other authors to this topic the proved method of finite elements is used here.