Deryzemlia S. Stress-strain State of Steel-concrete Spans Using Rationalization of their Geometrical Parameters

The dissertation is devoted to the research of the stress-strain behaviour of steel-concrete spans work on bending under dead and temporary load. The literature analysis allows to conclude that nowadays the rationalization of steel-concrete cross-sections and using them in building construction and reconstruction are important issue. The dissertation presents the developed method of rational design of composite cross-sections that using for steel-concrete spans. The method is based on the equal strength criteria of the extreme equal from the neutral axis of the cross-section elements. To achieve this propose the search algorithm of rational geometrical parameters of transformed cross-section limited by a range of values have been carrying out. Using the software package LIRA-CAD 2018 Pro (License №1/6638), the finite-element modelling of steel-concrete bridge span behaviour is carried out to verify and finalized the obtained results taking into account the multistage work of the span (structural non-linearity), physical non-linearity and concrete creep, redistribution of stresses due to the compliance of a flexible connection over the contact between concrete and steel. The efficiency of the composite reinforced concrete will not decrease with time and will depend on the rational compositions of the concrete to minimize creep deformations and the optimal ratios of the design parameters. Finite-element modelling allowed to carried out the analysis and estimation of stress-strain of bridge spans and allowed to appoint the rational design of three-span steel-concrete bridge.