Ksenofontnova T.K.

Candidate of Engineering Sciences (Ph.D.), Associate Professor, Russian State Agrarian University-Moscow Timiryazev Agricultural Academy, Institute of Land Reclamation, Water Management and Construction named after A.N. Kostyakov; Department of Engineering Structures, Russia

Calculation of monolithic buildings structures taking into account the nonlinear operation of reinforced concrete

https://doi.org/10.58224/2618-7183-2024-7-1-4
Abstract
Buildings and structures made of reinforced concrete are currently designed, as a rule, under the assumption of linear work of the material. However, in accordance with the requirements of modern standards, it is necessary to take into account the nonlinear operation of concrete and reinforcement in calculations. In the research presented in the article, using the example of a building with a wall structural system, the influence of taking into account the physical nonlinearity of reinforced concrete on the operation of its structures was considered. It was received that due to the nonlinear operation, there is a prospect of a possible reduction in the calculated forces affecting the strength and width of crack opening, and, consequently, the reinforcement consumption. In addition, when taking into account the work of reinforcement in the zone of yield stresses in ceilings and walls, local plastic areas may form that require reinforcement, which are not fixed in linear calculations.
The calculations were performed in the LIRA-CAD 2021 software package. The results of the calculations showed that taking into account the nonlinear operation of reinforced concrete when considering the floors of a building allows reducing the design efforts compared to calculations performed in a linear formulation by about (3 - 30)%, and when calculating walls, on the contrary, taking into account the physical nonlinearity of reinforced concrete, internal forces increase in some cases more more than twice. Taking into account the physical nonlinearity of reinforced concrete work also leads to a more correct assessment of floor deflections.
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Consideration of dynamic impacts in the design of cantilever structures

https://doi.org/10.58224/2618-7183-2022-5-6-54-63
Abstract
The article is devoted to the question of the influence of the constructive solution of cantilever structures on the indicators of rigidity and dynamic comfort of the building. The analysis of the influence of the solution of cantilever structures on dynamic indicators is carried out on the example of a building with a metal spatial frame having a cantilever part with a span of 22 meters. Two variants of the building frame were compared in terms of rigidity and dynamic comfort under wind and seismic influences. The calculations were performed in the certified software package "Lira-SAPR". A modal analysis was performed, the frequencies and forms of natural oscillations were determined, the maxi-mum acceleration of the overlap of the cantilever part of the building was determined. It is established that with constant metal consumption, increasing the height of the crossbars due to the use of through structures can significantly increase the rigidity of the system and provide the required indicators of dynamic comfort. Performing dynamic calculations at the stage of variant design allows you to choose the optimal variant of the structural solution of the building
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