Artomov V. Enhancement of calculation the deflected mode of bridge constructions taking into account dynamic influence of freight trains

The Doctoral thesis is devoted to questions of enhancement dynamic influence of bridge constructions. For the description the spatial fluctuations of bridge span structure is proposed to use the direct integration methods of movement equations of discrete rod system. The finite element method is used for determination parameters of deflected mode into span construction elements. The knots equations movement construction is presented by the form of Newton-Euler's differential equations which are integrated by Runge-Kutta's method. Dynamic influence on bridge from the railway vehicles is offered to model groups of movable contact forces with constant and harmonic components. The software complex is developed on the basis of the stated algorithm. The given approach is applied for calculation of reinforced concrete and steel girder bridges in the conditions of admission the freight trains with various speed of movement. The displacements, speeds and nodal construction accelerations are received, and corresponding plots, including the phase trajectories are constructed. The influence of dry friction forces in basic construction parts, armature prestressing, railway track irregularities for reinforced concrete span structure is investigated. The analogy between the forced oscillations of girder reinforced concrete and steel bridges on the basis of the phase trajectories analysis is spent. Comparison results of numerical modeling with data natural experiment is resulted. The spatial dynamics of steel span structures with through truss is researched, also the dynamic work analysis elements of the lattice main girders, longitudinal and cross beams of carriageway. The most load and susceptible to dynamic influence of freight trains construction elements are established. Critical speeds of train movement are received. The offered method of the analysis can be used also in engineering practice industrial and civil building objects for dynamic calculation of building constructions, buildings and structures. The results of the Doctoral thesis are implemented in practice of engineering and operational organizations of Ukraine.