Nauka ta progres transportu (Jun 2017)
STRESS-STRAIN STATE OF BEAM STAGED CONNECTION POINT OF THE RAILWAY BRIDGE TRACK-WAY
Abstract
Purpose. The staged connections of the beams of railway bridge track-way have the simplest design, but some design flaws result in numerous defects. The purpose of the given work is to research the actual stress-train state of the point of connection of the stringers with the floor beams on condition of their staged interposition. It is also necessary to determine possible effect of coupled work of deck beam grid and booms on their stress-strain state. Methodology. To reach the purpose of the study the testing of the existing bridge was conducted. To measure strains (stresses) in the span elements we used the strain gages glued to flange angles of stringers and floor beams and to fillets of lower flange angles of stringers in the points of their support on floor beams. To measure deflections of the truss, stringers and floor beams from static loads we used Aistov’s and Maksimov’s deflectometers, that were installed on lower boom in the middle of span 0-1, as well as on both stringers and floor beams in the middle of the span. Deflectometers were fastened to the span and, by wire communication, to the ground surface. Findings. Stress-strain state of the point of connection of the stringers with the floor beams on condition of their staged interposition was obtained and analyzed. Analysis indicates that, apart from vertical bending of the stringers and beams, there is a significant effect of horizontal bending of floor beams and their torsion, that occur due to the coupled work of track-way beams and top booms, both for P0 beam and for other beams. Originality. Research of stress-strain state of metal track-way staged beams while considering their coupled work with bearing trusses. Practical value. While testing the span under the train load, there are significant additional stresses from horizontal bending of floor beams and their torsion in the floor beam flanges. The appearance of these stresses is caused by inclusion of stringers into coupled work with top booms. Appearing flaws in stringers are caused by local stress concentration due to design features of staged track way.
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