Kazakevitch Mykhaylo
Problems of cable stabilization
Dnepropetrovsk National University of Railway Transport
Abstract. The report is devoted to one of the most complex problems of reliability and durability control of the up-to-date cable-braced large-span bridges not only in operation but in assembling too. The report comprises the data in brief about the physical processes of occurrence and conditions of existence of intensive vibrations of cables under wind, seismic and moving loads. There are given the energy spectra of wind and seismic loads and their specific peculiarities are described and that allows determining the intervals of the natural-vibration frequencies of flexible structures, including cables sensitive to these two most important natural phenomena. There is considered a mathematical model of cable vibrations which is the base to calculate the cable frequency spectra depending on their length, drawing power and the number of the frequency form. By the example of the cable-brace bridge over the channel Bosporus the Eastern on the island Russian in the city of Vladivostok of the span as long as 1 104 m there are analyzed the dynamic characteristics of the span structure at the stages of assembling and in the operation, the cables are analyzed in the process of operation. An extremely dense discrete spectrum within the intra-low frequencies in the range of 0,06–1,00 Hertz. There is shown the cable sensitivity to such meteorological factors as ice and hoarfrost loading, heavy showers and monsoon rains, and their influence on the dynamic behavior of the cables under wind loading. There are also analyzed advantages and disadvantages of the existing ways of the stabilization of cable vibrations under wind loading especially in the process of assembling. There are given the guidelines on the efficient ways of the cable stabilization and on their constructive decisions.
Keywords: cable-brace bridges, cables, stabilization, energy spectra.
Gorokhov Yevgen, Pichugin Sergiy, Makhinko Anton, Nazim Yaroslav
Experimental determination of the combined aerodynamic characteristics of building and structure models
Donbas National Academy of Civil Engineering and Architecture
Poltava National Technical Yu. Kondratyuk University
Abstract. The article is about the procedure of determining the aerodynamic characteristics of solid-wall and frame structures in the DonNACEA wind tunnel. For this purpose there have been developed and designed a three-component aerodynamic balance and an instrument panel which make it possible to evaluate the response of the structures along and perpendicular to the wind flow and an aerodynamic moment. In the aggregate it allows carrying out the dummy test of any complexity for buildings and structures varying ion the aerodynamic form. The developed system of determining the combined aerodynamic characteristics of building and structure models guarantees accuracy sufficient for the engineering practice at the minimum timetable to prepare the initial data and to analyze the observations. A continuous journalizing of the testing results in the digital format makes a further analysis easier with the help of different systems of the statistic and regression analysis.
Keywords: wind tunnel, wind, aerodynamic balance, head resistance, lifting force, aerodynamic moment, dummy test.
Bannikov Dmitry
Design of steel bunker capacities on the base of the panel construction diagram
Dnepropetrovsk National University of Railway Transport
Abstract. An available traditional construction diagram of bunker capacities for bulk materials has some disadvantages which decrease reliability and longevity of these structures. Nowadays, they are searching and developing more perfect and up-to-date constructive decisions. One of them is the panel construction diagram based on the use of steel corrugated plates suggested by the author. In the article the author compares the design of a bunker capacity worked out in accordance with the traditional approach and in accordance with the panel diagram. There are compared the principal design characteristics of the both variants under study. It is shown that the use of the panel construction diagram makes it possible to considerably improve the basic design characteristics of bunker capacities for bulk materials, to obtain a more uniform picture of the deflected mode, materials consumption being decreased up to 1.5 times.
Keywords: bunker, bunker capacity, traditional construction diagram, panel construction diagram, bulk material.
Boldyrev Alexander, Sventikov Andrey, Sventikova Anastasiya
Evaluation of reliability of beam and suspension combined structures
Voronezh State University of Architecture and Civil Engineering
Abstract. There is presented a technique of evaluating reliability of steel beam and suspension structures based on the idea of the direct assessment: emergency situations for a probabilistic design are considered on grounds of the nonlinear design of a structure. A direct probabilistic estimation was done with the use of the method of statistical tests in the form of modified stratified retrievals. The statistical record of the development of plastic deformations was done on the base of the suggested criterion of small-scale plastic deformations. The general reliability of the constructive system is estimated by the criterion of a material failure. The suggested technique is illustrated by considering a single-span suspension system with vertical suspenders. On the base of the failure criteria formed there was suggested a classification of technical states of beam and suspension structures.
Keywords: structure, core, flexible cord, estimation, strain, deformation, plastics, probability.
Gubanov Vadim, Golikov Alexander
Specifics of designing chimneys with rigid braces
Donbas National Academy of Civil Engineering and Architecture
Abstract. The constructive decisions as to the braces for chimney shafts to be fastened have been classified. There are presented the results of the numerical calculations of chimneys with different types of braces. There were determined the application limits for each constructive decision of braces examined. The influence of the brace geometry on the NDS of the combined system «chimney – rigid braces» was studied in general, the influence of the brace height and the brace gradient angle on the system deformability was determined. There was studied the influence of the type of the joint of mating a chimney shaft and the brace design on the NDS of the system in the large. A necessity of taking into account temperature deformations in the development of the constructive decisions of the carrying unit was highlighted.
Keywords: chimneys, shaft, braces, carrying unit, mating, mode of deformation, constructive decisions, load-carrying capability, deformability.
Yugov Anatoliy a, Mironov Andriy a, Bondarev Oleksiy a, Moskalenko Volodymyr b
Investigation of the influence of initial imperfections in the gsp frames of series 1.263.2-4 on the parameters of the mode of deformation
a Donbas National Academy of Civil Engineering and Architecture
b «Prombudremont», Ltd
Abstract. The article is about the influence of the initial imperfections in the GSP frames of series 1.263.2-4 on the parameters of their mode of deformation. There are presented the design diagrams of the frames under study and the analysis of the results regarding the initial imperfections. The numerical investigations have been analyzed. There are given the guidance of decreasing additional efforts in the frames. The obtained values of the additional efforts and stresses which indicate that the initial imperfections influence the real mode of deformation of the frame of the series under consideration. An imperfection being taken into account at the stage of designing, it will make it possible to hereafter increase the operational reliability and survivability of the structures. The findings of the investigation and the guidance can be used in the design and development of new analogous GSP structures. It is suggested to develop a procedure of taking into account the initial imperfections as a constituent of the universal design and graphic software package Structure Cad or some other one.
Keywords: metal structures, geometric imperfections, structure manufacture, MKE, mode of deformation, accuracy, numerical investigation.
Gubanov Vadim, Udod Iuliia, Cheburey Darya
Design of tubular cores of towers for their aerodynamic instability
Donbas National Academy of Civil Engineering and Architecture
Abstract. In article the condition of a question is analyzed and tubular cores of towers for their aerodynamic instability have been designed according to the offered technique and Eurocode 1: Actions on structures – Part 1–4: General actions – Wind actions and the practical way of defining of the dynamic force influencing the merely fixed and rigid fixed element under the nomogram, depending on diameter, length and thickness of pipes also is developed. The nomogram for electric welded straight line pipes in accordance with GOST with 60–102 mm diameter to define sections of elements where there is no wind resonance, at a stage of acceptance of the basic constructive decisions is presented.
Keywords: a tubular core of a tower, wind loading, a resonance, dynamic force, whirl excitation.