Denisov Evgeniy
Vibrating method of efforts determination in a truss structure using a special stand
Donbas National Academy of Civil Engineering and Architecture
Abstract. Methodology of realization and results of experimental researches of the vibration method of determination of longitudinal efforts in the bars of truss structure are given in the article. Tests have been carried out with the help of a special experimental stand, that mainly allows to change the length and flexibility of an examinee element correspondenly, and also the size and the sign of a longitudinal effort in it. The longitudinal effort has been determined with two independent methods – strain measurement and vibration. Calculation parameters of a dynamic model of vibration method they are effective length of the bar and condition of its end-capping fixing have been specified by the way of weights-variation method. Besides the method of weights-variation for determination of coefficients values of angular inflexibility of supports the bar has been tested statically by means of a point transversal load in the middle of the span with the further moment diagram and its analysis. For every method of determination of longitudinal efforts the range of possible errors of measuring and calculations has been considered. Finally divergences of middle values and confidence intervals of the efforts got with two methods have been analyzed.
Keywords: vibration method, weights-variation method, dynamic tests.
Chub Alexander
Organizational principles of decision-making process in the recovery of urban objects
Zaporizhzhya State Engineering Academy
Abstract. The paper addresses the problem of repair, restoration and increase of the operational longevity of concrete bridges, crossings, pavements and many other objects, and attempts to use scientific organizational principles of organizational planning and decision making in maintenance and restoration of municipal facilities. The methodology of organizational decision-making, illustrated by the example of rehabilitation of reinforced concrete structures, which similarly can be used when carrying out other works: weatherization, painting, repair of buildings, communications, etc. Proposed organizational principles which allow to optimize and efficiently use the potential repair services of cities, to use of expense budgets more efficiently, and to plan repair work in policy terms. Investigations are related to the improvement of technologies to increase the durability and maintenance-free period of operation of municipal facilities. Developed technology at the design stage of production processes and organization of work, allow to control and regulate the quality of materials and parameters of technological processes of preparation, delivery, installation, compaction and curing of concrete mixtures, due to their influence on strength and frost resistance of concrete. As a result, there is significant economy of labor, material and energy costs.
Keywords: technological and organizational solutions, repair, restoration, link, hook.
Orlov Stanislav, Zakharov Victor, Orlova Alla
Research of the combined cyclone with direct-flow elements
Donbas National Academy of Civil Engineering and Architecture
Abstract. Direct-flow cyclones are widely used for gas cleaning from dust. However, due to low efficiency, they are mainly used as a pretreatment gas cleaning from dust to reduce the load on the fine cleaning machines. The analysis of the combined direct-flow cyclone with the elements in which, for better concentration of dust both the centrifugal and Coulomb forces are used. It is known that near the corona electrode, the Coulomb force is much greater than the centrifugal force, but as the distance increases it decreases rapidly. Centrifugal force, on the contrary, increases linearly with increasing distance from the corona electrode. It is found that for particles of a certain size there is the distance from the corona electrode, where the centrifugal and Coulomb forces are equalized. At this distance, the resultant force (the action of Coulomb and centrifugal forces) becomes minimal. The minimum resultant force can significantly simplify the theoretical analysis of the mechanism of dust concentration, assuming that this force is constant throughout the interelectrode space. It is found that the combined effect of Coulomb and centrifugal forces significantly increases the efficiency of direct-flow cyclone, so further researches in this direction are promising.
Keywords: cyclone, centrifugal forces, coulomb force, speed.
Tymofyeyev Mykola, Sahnovskaja Svetlana, Boklag Svetlana, Petunina Anastasija
The efficiency of fragmentary heat insulation of external walls
Donbas National Academy of Civil Engineering and Architecture
Abstract. Nowadays to improve the microclimatic parameters of the houses tenants of apartments of multi-storey buildings warm external walls by themselves. This is done in some apartments either from inside or outside the buildings. Such works are carried out without a project and any necessary thermo technical calculations. Therefore, they do not consider the negative consequences of the first method, related to the vapor permeability of the inner layer, and the low effectiveness of the second one. Such types of work are prohibited by new normative documents on fulfillment of repair works and reconstruction of buildings. The absence of obvious results of research, capable in demonstrative form to indicate the impracticability of such kind of works, is one of the reasons for the current state of affairs. In this paper, we have considered the basic constructive ways of inner and outer fragmentary warming of external walls. On the basis of numerical modeling of temperature fields of characteristic match of the walls to the ceiling the minimum temperature in the corners of the joints is defined, values of linear coefficients and the heat resistance are found. The inefficiency of fragmentary wall heat insulation for heat insulated flats and a slight improvement of temperature characteristics in the adjacent apartments are found. The efficacy of external thermal insulation of walls is proved, when the entire surface of the walls is thermo modernized.
Keywords: numerical simulation of the temperature field, thermal resistance, heat insulation of walls.
Velychko Valentina, Kutsevol Lyudmyla
The problems of stabilization of loess subsided soils for bases and foundations
Cherkasy State Technological University
Abstract. The article handles the problem of base and foundation arrangement on loess subsided soils. The main features of the loess soils are given. The article gives analysis of the effect of these features on the base and foundation arrangement on loess subsided soils. The existing methods of loess subsided soil stabilization, as well as problems of their implementation are analyzed.
Keywords: loess subsided soil, base, foundation, compaction.
Gavriukov Alexander, Kralin Andrey, Talalay Victor
Prospects of using belt conveyor with a varied length and curvilinear drums
Donbas National Academy of Civil Engineering and Architecture
Abstract. The development of construction machines with a tubular belt conveyor operating with a varied length requires length shortening of the transition section from unrolled belt into tubular one. The use of concave drums and belts is one of the upcoming trends to resolve the problem. The paper presents a construction design of construction machines with a tubular belt conveyor operating with a varied length, their use is to increase labour productivity, as well as tubular conveyor excavating machines used for well-drilling and conveyor-cranes used for concrete handling in high-rise construction. It has been shown that the use of concave drums and belts allows to increase the engineering performance standards of the conveyors with varied length due to transition section reducing from unrolled belt into tubular one, its size being two times less than transition section from flat belt into tubular one.
Keywords: continuous-type machines, conveyor belt, cylindrical drum, curvilinear drum, tubular conveyor, power requirement.