The primary objective of the presented project was to determine the static response of the Railway Bridge OSKAR steel structure during the construction phases. Load bearing structure consists of two single span skewed bridges – network arch bridges with orthotropic bridge deck. In course of computational purposes the spatial FE-model was created. Model considers realistic structural stiffness and its physical properties. The appropriate straining of each pull bar was determined separately for each of the construction phases – bar tightening, bar welding, bridge final activation.