Calculation of steel-reinforced concrete structures of the building of the National library of the Republic of Belarus

Abstract

The unique building of the National Library of the Republic of Belarus includes not only urban planning, architectural, technological modern solutions, but also structural ones. One of such modern structural solutions is the use of composite (steel-concrete) structural elements. Theadvantages of steel-reinforced concrete structures are manifested in the possibility of placing steel profiles of large cross-sectional area in their cross-section and protecting them from corrosion and high temperatures with concrete; the use of rigid reinforcement as load-bearing elements or formwork during their construction. The article presents the results of applying a nonlinear analysis to obtaining of the parameters of the stress-strain state (normal stresses, strains) at any stage of behavior under loading, including the construction stage, as well as the strength, deformability of complexly loaded composite elements under the condition ofjoint operation of rigid steel sections and reinforced concrete. The resolving system of equations of the nonlinear deformation model includes the conditions of equilibrium of internal forces in the cross-section, the condition of distribution of relativedeformations along the height of the cross-section in accordance with the hypothesis of a flat section, as well as approximations of the deformation diagrams of concrete and rigid reinforcement in the form of rolled sections under tension-compression. A criterion for assessment the internal force corresponding to the resistance of a composite steel element, which does not require standardization of the ultimate compressibility of concrete and allows taking into account a high degree of redistribution of forces between the components in the cross section of the composite steel element is proposed. The advantages of the nonlinear design method are demonstrated with usage of the examples of calculatingcomposite steel structures of the building of the NationalLibrary of the Republic of Belarus.