Yaroslav Huk
Methods of zoning of Transcarpathian region by maximum depth of soil freezing
Uzhgorod National University
Abstract. In the article numeric calculations of frost line in the 23 directions between 9 meteorological stations and migration stations have been carried out with the usage of methods of high-rise and high-winter coefficient. For the first time inmost depth of soil freezing for population centres, tops and dam plates of Transcarpathian Region have been determined numerically. Defferences in analysis of depths of soil freezing by two different methods are 1–5% and in such case the methods are considered self checking. Machinery use is based on short-cut calculation of heat transport theory and heating capacity, heat conduction and liquid limit of soil, and also tightness and heating capacity of snow cover are taken into account. In the article classification of land area of Transcarpathian Region of Ukraine in the depth of soil freezing has been done based on estimate indicator. The usage of suggested methods by rating of soil freezing factors allows to carry out detailed numerical simulation of maximum deep of soil freezing in other regions of Ukraine.
Keywords: depth of soil freezing, weather stations, transition station, high lift coefficients, high altitude snow ratios.
Vitaliy Gichko
Stability design of elastic reinforced-concrete poles by bending method
State enterprise «The state research institute of building constructions»
Abstract. There are purposes, tasks of theoretical and experimental research and ways for their solution by calculation of flexible eccentrically compressed reinforced concrete elements stability using the deformation method. There are main provisions of developed calculation methods which are based on the use of real reinforcement and concrete deformation diagrams: methods which consider the peculiarities of elements work used for reinforcement concrete elements of different flexibility and used materials including those ones made with the use of high-strength concrete. The developed «exact» method which makes it possible to determine the stress-strain state of normal bar sections by deformation method with further determination of the element state is described. The actual deflection appeared in the process of loading is considered during the calculation. The developed simplified method of flexible eccentrically compressed reinforced concrete elements is given in the report. The given calculation method is based on the assessment of the most stressed section strength and on the use of real sections stiffness (B = M /ℵ) calculated by determination of their stress-strain state using the deformation method. Thus, high accuracy of obtained results is achieved. The quantitative and qualitative assessment based on the compared data of experimental research of flexible eccentrically compressed reinforced concrete poles under the short-term load which is performed by the author of the report and other two researchers (A. N. Bambura and R. H. Kayumov) with the results of their calculation according to the developed methods is given. The analysis of obtained static distribution parameters shows that the proposed calculation methods give the stable results in assessment of critical load. Thus, at calculation by «exact» method the variation coefficient is VС = 8,5 % and at calculation by simplified method it is VС = 15,5 %. Based on the results of performed researches there are basic conclusions including the possibility to use the given methods in practice of reinforced structure design in future.
Keywords: stability, load-bearing capacity, deformation method, «exact» method, simplified calculation method, accuracy assessment.
Sofiya Burchenya, Ivan Dobrianskyi, Roman Shmyh
Influence of covering concrete layer on crack resistance stress-strain behavior and bearing capacity of concrete beams reinforced by cut-stretching sheet
Lviv National Agrarian University
Abstract. Concrete, smooth and fluted corrugated bar reinforcement, flat and fluted sheet steel, shaped roof deck are used, as a rule, for prefabricating reinforced concrete beam structures with external sheet (ribbon) reinforcing. However the scientists passed by the rather interesting type of sheet reinforcement called cut-stretching sheet. Due to its particular geometrical shape of lateral surface and strength features cut-stretching sheet can also be used as external reinforcement in reinforced concrete structures. Good adhesion between concrete and steel without using additional connecting items and strength of structure are provided by this type of reinforcement. It also decreases stress-strain behavior of concrete tension zone and solidity of reinforced concrete. The experimental results of researching of reinforced concrete beam specimen reinforced by cut-stretching sheet are provided in the article. The influence of available or unavailable covering concrete layer on crack resistance, stress-strain behavior and bearing capacity has been found out.
Keywords: steel concrete beam, crack resistance, crack opening displacement width, cut-stretching sheet.
Andrij Prishenko
Device openings in exterior walls with additional warming deepening outside
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article describes a new method for energy-saving devices of the window opening in the outer wall, wherein the outer perimeter to perform special recess. In the recesses located an additional layer of insulation, which aims to eliminate the formation of cold bridge and improve thermal and technical indicators interface – the minimum temperature on the inner surfaces and reduced thermal resistance. For brick and monolithic concrete walls proposed minimum allowable size of the cross section of the recess analyzed technological capabilities Arrangement of recesses defined direct economic benefit for the new constructive solutions openings in brick or concrete walls. Theoretically, a numerical simulation model for the solution of a brick wall for different thicknesses of insulation in the front with a thin layer of thermal insulation plaster the values of temperature and heat flux. Based on the results of laboratory tests in a climate chamber to determine the reduced heat transfer resistance at the top of the window opening, which values due to additional warming interface compared with a window and a quarter increased approximately 2-fold.
Keywords: thermal insulation of walls, window opening, temperature field, resistance to heat, constant climate сhamber.
Viktor Yarkin, Stanislav Polivtsev, Hanna Kukhar, Tetyana Kosheleva
Internal bed soils consolidation with application of hardening mortars
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper deals with the principle trends of development of internal bed soils consolidation at refurbishment with application of compaction and stabilization of foundation bed soils by hardening mortars, field of their application, efficiency of their application. The effect on bed soil composition of the applied technique and stabilizing mortars is determined. The influence of technology in use and fixative solution structures on quality of hardening of soil structure are found out. The recommendations on perfection of the bed soil consolidation methods, building operation techniques, the set of equipment, compositions of hardening mortars and field of their judicious application have been algiven. The proposed anchoring mortars are characterized by small consumption of binding agent by high sedimentation stability, fluidity, great penetrability, resistance to washout during hardening period, lower cost at sufficient strength. It has been established that the field of rational application of the proposed methods of the internal soil consolidation is foundations of refurbished buildings and structures, of fine-grained soils, macroporous undertemped dust and clay soil, including subsiding ones. The recommendations on application of the results of carried out investigation and improvement of complex methods of consolidation of foundation bed soils in execution of construction work of Donbas and at refurbishment of buildings and structures have been worked out.
Keywords: foundations, refurbishment, compaction of foundation bed soil, internal consolidation, perfection of consolidation methods, processing sequence of operations, set of equipment, composition of hardening mortars, research, field of application.
Grigorii Gasii
Laboriousness assembly of steel and concrete composite construction
Poltava National Technical University named after Yuri Kondratyuk
Abstract. Considered a new type of structures – structural composite of cable coatings. Reflected the characteristics of constructive solutions. Structurally composite cable-stayed structure-coating is a complete spatial system consisting of plates and cross-rod trusses. Moreover, the lower belt is formed of flexible elements and the upper plate of ferro-cement. Obstacle to the implementation of the test in the construction of structures is the lack of installation technology. Based on the results of experimental and theoretical studies, developed the technology of mounting surface. Determined the overall complexity and scope of work adopted the proposed installation technology. To determine the complexity of calculations were performed costing labor and machine time.
Keywords: composite cable-stayed structure-coating, assembly, labor costs, laboriousness.
Volodymyr Korsun, Andrii Niedoriezov
Variant of elastic-plastic and pseudoplastic concrete deformations regularities subscribe in conditions of volume stress state
Donbas National Academy of Civil Engineering and Architecture
Abstract. Propositions for inprovement of modified strain theory variant developed in DonNACEA are presented. Analytical expressions, wich allow to subscribe the basic components for general case of volume stress state as elastic-plastic strains, wich don’t relate with destruction of concrete structure and pseudo-plastic strains due to regularities of concrete structure destruction, are made. As initial shear-displacement model of concrete structure destruction by type of three-dimentaional directed «zigzag crack» are adopted. Developed modified variant of concrete behavior model are formed up on the combination of solutions based on relations of solid mechanic and fracture mechanic. Verification of model are made by comparison of estimated values of A. V. Yashin, H. Kupfer, M. Tasuji и S. Schröder at conditions of unaxial stress states.
Keywords: concrete, volume stress state, strenth, strain, compressibility, dilatation, behavior models.
Yaroslav Nazim, Yevgeny Shevchenko
Reconstruction of large transmission line crossing on the river Dnieper in Kremenchug
Donbas National Academy of Civil Engineering and Architecture
Abstract. The subject of research in this article is the double circuit large transmission line crossing 154 kV «Kremenchuk Hydroelectric Station – Kremenchuk Heat and Power Station» on the river Dnieper. The responsibility of the given construction is not established only by that fact, that given overhead transmission line is one of power supply lines of Kremenchuk, but also its intersystem value. Calculations have been performed by means of developed software package, which is based on the digital and analytic methods of definition of stresses and deformations in element of structures of OPTL as part of common system. That allowed defining numerical value of loads from the conductor line and overhead ground-wire cables in a normal and emergency mode of operation on the structures of overhead power transmission lines, as well as efforts in the most stresses elements of supports. According to the results of calculation during the reconstruction it was made the local strengthening of structures of towers and supports. This article describes the manufacturing process of works on replacement of conductors and overhead ground-wire cables by installation them on the surface of water, that allowed to reduce term of reconstruction and loads on the supports. On the whole, realization of work allowed raising indicators of imparted electrical power when the considerable reduction of materials-output ratio (without renewal of existing supports), and also to increase the reliability of the intersystem of OPTL section.
Keywords: overhead power transmission line (OPTL), large transmission line crossing, reconstruction, conductor line, tower.