Application of geodetic methods to refine boundary conditions in digital twins of war-damaged multi-story buildings

The object of the study is the buildings and structures of Ukraine, which suffered significant destruction as a result of the Russian invasion. The research focuses on the formulation of an applied methodology for deformation and geodetic monitoring of such buildings, based on the geodetic instruments widely used in Ukraine. The methodology was developed and experimentally validated over a five-year period at a test site located in a densely built-up urban area of Kyiv, characterized by a slope elevation difference of approximately 15 meters. The methodology encompasses monitoring of vertical and horizontal deformations, crack propagation in buildings adjacent to the construction site, and inclinometric monitoring of slope deformations. Subsequently, the methodology was applied to refine the boundary conditions of a damaged multi-story building at 6-A Lobanovskyi Avenue in Kyiv, which sustained a missile strike on February 26, 2022, affecting the structure between the 18th and 22nd floors. It was determined that deviations from the reference horizontal plane at the 25th floor slab reached up to 241 mm, with the maximum deformations concentrated at the impact site. The relative difference in vertical displacement was 0.0448, exceeding the normative limit of 0.005 by a factor of nine. These experimental findings were used to refine the initial and boundary conditions of the digital twin model of the building and significantly altered the stress-strain state in comparison to an undeformed analogue. The results of the deformation monitoring and the corresponding numerical simulations were subsequently integrated into a BIM model of the building and informed its restoration strategy