Perspective constructions of bridge overpasses on transport main lines

Abstract

Abstract. When designing bridges on motorways and railways, conventional beam or trussed design schemes of structures made of steel or reinforced concrete are used, but at present there is a significant increase in the speeds of motion of individual vehicles, axial loads and total train weight increase, and temporary intervals between trains. These factors lead to a significant increase in dynamic effects and necessitate the use of non-classical design schemes for artificial structures of transport infrastructure. In this study, it is proposed to take a threespan arch bridge with suspended central span structure as the basis for unified bridge overpass. Such an arrangement will allow changing the design length of the central span in a fairly wide range, reducing the total number of supports with an increase in the total length of the bridge overpass, and using a similar design as a double-track railroad, two- or four-lane motorway bridge. Calculations carried out and the results obtained for calculating displacements, internal forces and stresses in the units and elements of the proposed bridge overpass design allow concluding about the allowable limit values of the values found, sufficiently uniform load of all its main elements, the absence of strongly marked large-scale stress concentrators. Proposed design allows setting different sizes of spans during the design, reducing the number or even avoiding the installation of channel supports, adapting this structure for the passage of both rail and road transport. Design of the bridge, mathematical model of which is described in detail in the article, can be manufactured at the factory, and then delivered to the installation site and mounted there, which significantly reduces the final construction cost and makes it a profitable solution, for example, for arranging railway interchanges at different levels.