Study of Railway Steel Bridges’ Behaviour in Order to Identify the Causes of Their Defects

Abstract

ENG: The purpose of this work is to clarify the causes and mechanism of premature origin of defects in the elements of the bridge deck with the storey connection in steel span structures of railway bridges by studying the stress-strain state of their deck beams. Research aimed at extending the service life and increasing the carrying capacity of metal girder structures with a low load class and at the introduction of a new design solution for connecting the nodes of the deck beams, which is extremely important to ensure the necessary railway capacity and train safety. Service life and reliability of stringer beams of a deck definitively defines a service life and carrying capacity of all span structure. In order to deepen the analysis of the experimental data of the tested structures, calculations of the structure with the initial data, that fully correspond to the experimental span structure, were performed. For theoretical researches the underslung span structure with through trusses, designed by "Proektstalkonstruktsiya" with the nominal span of Ln = 44,0 m with a storey carriageway was chosen, as the one having the greatest number of defects in nodes of stringers support by the floor beams. According to the results of calculations and computer simulations, it is determined that the main cause of cracks is the structural imperfection of the aforementioned nodes, that is typical of similar structures.