Along with new construction, the issue of reconstruction of existing buildings and structures in Ukraine remains relevant. The topical issue is to bring a significant number of previously erected buildings in line with today's requirements. Today, many buildings and structures for various reasons are in poor or emergency condition, are preserved or even abandoned. Some of them may get a second life after changing the purpose of the premises, expanding the area, increasing the number of floors, replacing load-bearing structures, etc. However, existing load-bearing structures often require partial or complete reinforcement due to physical wear or increased load after reconstruction. Ensuring reliable operation of buildings after reconstruction, meeting modern needs and requirements while preserving attractive historic facades is an urgent task for many facilities in our country and especially in the capital.
 The study was performed on the example of a real object in Kyiv on the reconstruction of an administrative building with a superstructure and extension of non-residential premises. The reconstruction project provided for the redevelopment of the main building, which according to archival data was erected by the 1940s. The reconstruction project also provided for an increase in the number of floors in the pavilion, which was added in 2000. And also, the extension of non-residential premises was provided.
 As part of the study, an analysis of the redistribution of forces in the load-bearing structures was performed, taking into account the subsidence of the foundations of new supports. The change of internal forces in the load-bearing structures of the metal frame was analyzed according to numerical simulations taking into account the influence of the soil base, which is manifested in the occurrence of uneven movements of the bases of the columns.
 The aim of the study is to analyze the redistribution of forces in the load-bearing structures, taking into account the subsidence of the foundations of new supports based on the results of numerical modeling of the interaction of elements of the system "soil base-foundation-building". To realize this:
 
 the bearing capacity of the existing foundations was checked in the conditions of the house reconstruction;
 the combination of loading on the bases under new support according to results of spatial calculation of a metal framework of an extension is defined;
 the movement of the bases of the columns was determined to calculate the spatial work of the metal frame of the extension, taking into account the subsidence of the foundations;
 the analysis of redistribution of efforts in bearing designs is considered taking into account subsidence of the bases of new support.
 
 It is established that taking into account the deformation of the foundation base significantly affects the stress state of the aboveground structures of frame structures, which increases the reliability of all elements of the frame.