Gorbatyuk Y. The improving of the design and checking the calculation of a stress-strain state of the floating bridges

Object of research: bearing constructions of raft bridges for railway and automobile loads.Aim: improvement of span bridge constructions, raft bridge pontoons and calculation models of their stressedly-deformed states, substantiation of exploiting the raft bridge potentialities in civil and transport building. Investigation methods: the experimental-theoretical method of the research in which theoretical calculations are corrected by the experiment results is used in the dissertation. The numerical computations are carried out in the parametric modelling and engineering analysis environment Belinda Structure 2014 (the licence number GUN-DN20142015) that realizes the method of finite elements in combination with Euler and Newton's dynamic equations for framework. While improving the bearing constructions of the bridge spans, the methods of the rational design of the metal constructions were used. Theoretical and practical results: consist in designing the raft bridge constructions that are recommended for application in Ukrainian Armed Forces as well as in the temporary and capital constructions in civil building. Dissertation results were introduced into the practical work of the pontoon bridge subdivisions of State Special Transport Service of Ukraine on two raft bridges that were erected during (ATO) on the river Siverskyi Donets and the river Kazennyi Torets (Donetsk Oblast) in July-August 2014 as well as into learning process at DNURT named after Academician V. Lazarian. Scientific novelty: the improved pontoon constructions and span girders for the raft bridge building were proposed; the raft bridge calculation model which allows to analyse the construction conduct through time under the influence of external loads were designed; the new experimental data about the functioning of the raft bridge under the loads of railway and automobile transport were obtained; the data about the stressedly-deformed states of the constructions and dynamic specifications of the raft bridge according to the main parameters; the data about technical and economic activities of raft bridge constructions were obtained. Application extent: the technological peculiarities of the raft bridge building were proposed; the economic effect of the design decision application of the pontoon consisting of three sections and the span girders with the perforated wall were determined. Due to the substitution of the external sections of the floating bridge footing that don't carry traffic for the plastic ones as well as the use of the girder with the perforated wall, the expenses were reduced by 57%, and the total value of the materials for the raft bridge section building was decreased by 393.78 thousand UAH. Application field: temporary and capital passages for military and national economic construction.