Numerical modelling of temperature effects on the reinforced concrete overpass No. 11a of PJSC "Azovstal Ironand Steel Works" in Mariupol was carried out to assess the technical condition of building structures, identify possible defects affecting the strength and bearing capacity of the structure, load capacity and residual life, along with engineering surveys using instrumental methods, to develop a project for the overpass overhaul. A comprehensive methodology for studying the stress-strain state, strength and stiffness of structures was created and a calculations of tware package based on the semi-analytical modified straight line method was developed, which works along side the LIRA and SCAD calculations of tware packages and provides accurate and objective results. Based on the results of the study, the concept of the overpass reconstruction was adopted on the basis of the created spatial computer models and a project for the overpass overhaul was developed.