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Über dieses Buch

This book gathers the latest innovations and applications in the field of resource-saving technologies and advanced materials in civil and environmental engineering, as presented by leading international researchers and engineers at the 2nd International Scientific Conference EcoComfort and Current Issues of Civil Engineering, held in Lviv, Ukraine on September 16-18, 2020. It covers a diverse range of topics, including ecological and energy-saving technologies; renewable energy sources; heat, gas and water supply; microclimate provision systems; innovative building materials and products; smart technologies in water purification and treatment; protection of water ecosystems; and architectural shaping and structural solutions. The contributions, which were selected using a rigorous international peer-review process, highlight exciting ideas that will spur novel research directions and foster multidisciplinary collaborations.

Inhaltsverzeichnis

Frontmatter

Experimental Research of Strength Characteristics of Steel Fiber Reinforced Concrete Gutters and Modeling of Their Work Using the Finite Element Method

Steel fiber reinforced concrete and structures based on it have increased crack resistance, toughness and elasticity, abrasion resistance, service life and are less sensitive to vibration and shock effects than similar structures with typical reinforcement. These elements at short-term and repeated loads three series of experimental researches have been conducted. Testing of prototypes (gutters) is performed by applying a central vertical load to the metal traverse beam acting on the gutter as evenly distributed. The results of experimental research of strength characteristics the steel fiber concrete, reinforced concrete and steel fiber reinforced concrete in gutters under the action of single and repeated loads are given. The results of the simulation of gutters using the finite element method also presented. Increasing the percentage of reinforcement with steel fibers gives an increase in carrying capacity for SFRC gutters at repeated low-cycle loads. Cracks in RC and SFRRC samples were with direct nature, while in SFRC samples they were with net nature.

Oleksandr Andriichuk, Ivan Yasiuk, Serhii Uzhehov, Oleksandr Palyvoda

Influence of Nanoparticles on the Processes of Heat Accumulation During Material Phase Transformations

Heat accumulators are widely used to store and further utilize heat energy from solar collectors, heat pumps and other renewable energy sources. In this case, materials with phase or chemical transformations may be used. This makes it possible to significantly increase the accumulation of heat energy per unit mass of the heat storage material compared to the batteries on solid and liquid materials. To increase the efficiency of materials with phase transformations, fillers are used in the form of nanoparticles having a high coefficient of thermal conductivity. This paper presents the results of numerical modeling and experimental study of the influence of nanoparticles on the processes of heat energy accumulation in paraffin. The influence of geometric dimensions, concentration and thermophysical characteristics of nanomaterials on the processes of heat energy accumulation during paraffin phase transformations is investigated. Thermophysical properties of composite materials were investigated by optical spectroscopy. In experimental and numerical studies, the dynamics of melting processes of accumulating material with nanoparticles near cylindrical heat sources have been studied. A comparative analysis of heat-accumulating materials in the presence and absence of nanoparticles was carried out.

Ievgen Antypov, Valery Gorobets, Yurii Bohdan, Viktor Trokhaniak

Experimental Research of Strength Characteristics of Continuous Reinforced Concrete Beams with Combined Reinforcement, and Modelling Their Work by the Finite Element Method

The article presents an analysis of experimental research of work of continuous combined-reinforced concrete beams. The authors conducted experimental studies of two-span reinforced concrete beams in which classical rebar frames and dispersed reinforcement of concrete with steel fibers were combined. To investigate the effect of such reinforcement on the stress-strain state of the beams, load-bearing capacity and deformation characteristics, test specimens were made with three different variants of the steel fiber volume distribution, but with the same relative percentage of reinforcement. A numerical experiment was also performed in which the operation of the experimental beams was modeled by the finite element method. The results of this experiment, their analysis and comparison with laboratory data are presented. It is established that the dispersed reinforcement by steel fibers of the stretched zones of the beam reduces the stresses in the rod reinforcement, and allows to slowing down the development of plastic deformations in the reinforcement during the redis-tribution of forces in the inseparable beam.

Evgen Babych, Oleksandr Andriichuk, Mykola Ninichuk, Dmytro Kysliuk

Simulation of the Seismic Resistance of Buildings with Account of Unlimited Soil Space

The paper focuses on methods for dynamic analysis used in modern construction. The real object located in the Comintern district of Odessa region is taken as an example. When the earthquake loads are simulated, the authors use real accelerograms that were taken during the earthquake at the construction site of the object. For this construction site, several accelerograms were generated; they simulate 7 units of magnitude earthquakes from Vrancha zone and local focal zones. Analysis is carried out with obtained three-component accelerograms by the method of spectral analysis, and direct dynamic analysis was carried out. Described technique enables the user to simulate behaviour of the structural system of a building based on the finite elements developed and implemented in LIRA-SAPR program; these finite elements simulate vibration damping, to remedy the shortcomings of spectral and direct dynamic analyses. It also enables the user to solve physically nonlinear problems with soil and do not significantly increase the size, and respectively, time for analysis of the problem.

Maria Barabash, Viacheslav Iegupov, Bogdan Pysarevskyi

Between Tradition and Innovation: The Search for Modern Architectural Forms and Structures in the Design of Wooden Churches

Western Ukraine is known for its numerous examples of historic sacral wooden architecture, referred to as “tserkvas” in Ukrainian. In the Halychyna region alone, more than 1,100 wooden tserkvas are listed in government registers. Other regions have an approximately equal number. 16 of these are on the UNESCO World Heritage List, some as joint trans-border nominations of Ukraine and Poland. This historic heritage attests to a long tradition of wooden architecture in the region. Although architectural historians distinguish five primary stylistic groupings that have developed over time, all the groupings share a similar structural approach - horizontal wooden log construction. It would seem that with such a stable historical building tradition in place, and a bountiful supply of timber, the construction of new wooden tserkvas would continue indefinitely. However, that has not been the case. Very few new tserkvas have been built, and all of them have adhered to traditional construction methods. Lately, a perception has formed that the traditional horizontal log construction method has contributed to a lack of innovation and stylistic development in this notable architectural heritage. In light of that, a new initiative was formed with faculty from Vienna Technical University, to research new wooden materials and structural techniques that would permit a design evolution of contemporary tserkvas. An additional goal was to ensure a sustainable, environmentally sympathetic approach, much like the tserkvas of the past.

Mykola Bevz

Bearing Capacity of Stone Beam Reinforced by GFRP

One of the most common issues faced by builders during the reconstruction is the issue of durability and corrosion resistance of structures reinforced with steel reinforcement, especially in the presence of an aggressive environment in special purpose buildings. Annually new materials appear on the market of building materials that can change the idea of standard construction. Glass fiber reinforcement polymer is such the material highly resistant to aggressive environments. More than 40% of buildings are made of fine artificial stone materials (bricks, stones, blocks); it is an environmentally friendly material, which is also resistant to aggressive environments if the manufacturing technology is ensured. The rational combination of a brick and GFRP reinforcement together with maintenance of their reliable joint work will allow to develop more widely the field of this materials’ usage. Prefabricated load-bearing ceramic beams are relevant in terms of their economic use in construction, because they can be manufactured directly on construction sites, where it is impossible to provide access for machinery due to lack of space. Therefore it is good solution in terms of technical difficulties in installation of usual reinforced concrete lintels with the use of crane. The use of GFRP reinforcement has a number of advantages comparing with the classic steel reinforcement; coefficient of thermal expansion of reinforcement and concrete are rather close, which prevents formation of cracks when the temperature changes.

Zinoviy Blikharskyy, Taras Bobalo, Andrij Kramarchuk, Borys Ilnytskyy, Rostyslav Vashkevych

Influence of the Percentage of Reinforcement on the Compressive Forces Loss in Pre-stressed RC Beams Strengthened with a Package of Steel Bars

Pre-stressed reinforced concrete structures are widely used nowadays in construction industry. Such structures are rather cost-effective and give an opportunity to implement project ideas which are impossible without the use of pre-stressing technology. The issue of metal consumption reduction is highly topical. One of the possible solutions is the usage of steel-concrete elements with external reinforcement. The effectiveness of the use of reinforced concrete structures with external reinforcement has been repeatedly noted at international construction symposia and conferences. Application of advanced technologies and acceleration of scientific and technological progress in the construction field leads to increase in the reinforced concrete structures’ usage and expansion of application fields. Moreover, advanced technologies increase their efficiency and cost-effectiveness. This article describes results of research pre-stressed steel-concrete beams, strengthened with the package of steel bars with different ratio of sheet and rod reinforcement in the zone of pure bending moment action. The purpose of this research was definition of reinforcement percentage influence on loss on compressive forces’ loss in pre-stressed reinforced concrete beams strengthened with a package of steel bars. In addition the aim was to evaluate effectiveness of steel bars’ usage in combined reinforcement. The practical significance of the experiments is to study the loss of compressive forces in pre-stressed bending elements with tape and rod reinforcement, taking into account the influence of different ratios of reinforcement areas within the combined reinforcement and development of design and calculation proposals for such structures.

Taras Bobalo, Yaroslav Blikharskyy, Nadiia Kopiika, Myhailo Volynets

Experimental Research Results of the Bearing Capacity of the Reinforced Concrete Beams Strengthened in the Compressed and Tensile Zones

Construction is one of the main factors determining the economic development of the state. Introduction of new technologies and materials at the strengthened and restored reinforced concrete structures allows to solve important questions of the building branch. The article describes the experimental research of the work of layers of reinforced concrete beams strengthened by the glued composites in the form of carbon fibers in the tensile zone, and steel fiber concrete in the compressed zone. Namely, tearing the band off in the area between the point of application of the force and the support occurred, when the maximum permissible load had been achieved. The work of the strengthening concrete and the concrete of the beams took place simultaneously without sudden change of deformation. The significant effect of the strengthening system was found in the strengthened beams. Under single load there was an increase of bearing capacity in beams strengthened with fine-grained concrete by 57%. In beams strengthened with steel-fiber concrete by 46%. At low-cycling load for beams strengthened by the fine-grained concrete the bearing capacity increased by 32%, and strengthened with steel-fiber concrete by 69%. For beams strengthened under the loading of fine-grained concrete by 66%, in the beams strengthened with steel-fiber concrete by 65%.

Oleksandr Borysiuk, Yuriy Ziatiuk

Experimental Study of Compressed Ceramic Hollow Brick Masonry Structures Strengthened with GFRP Meshes

The article presents the results of the experimental study of masonry columns which have been strengthened after high-level axial compression loading with glass fiber reinforced polymer composites. Preliminary damaged ceramic hollow-brick middle-scale models were continuously wrapped with Glass FRP meshes in order to the testing program. The target point of this early exploration is to define the efficiency of the described method of strengthening for considerably affected models after their decompression. The “stress-strain” curves have been compared for confined and unconfined specimens. Reported results demonstrated raised load-bearing and ductility values for confined columns. In addition, the failure mode for wrapping has been noted and described. Control samples have shown brittle failure in contrast to strengthened samples’ plain collapse. Any atypical failure mode (due to sharp ceramic broken pieces) has not been observed. The paper also provides conclusions in terms of obtained experimental results and addresses numerical investigations to further research.

Serhiy Bula, Mariana Kholod

Simplified Method for Determining the Energy Efficiency of Window Blinds in the Field

Calculation of heat gain from solar radiation is a necessary part of simulating the energy balance of a building, which is an important aspect of the architectural design of modern energy-efficient buildings. Window blinds are an effective measure of the control of light and heat influence of insolation in buildings. Efficiency of blinds depends on many factors, such as position, material, distance from the sun and parameters of the microclimate and exploitation mode of the rooms where they are used. In the summer of 2019 a group of employees of KNUCA explored the sunscreens of the new office building in Kyiv with a high percentage of glazing. Efficiency of protection from glare and overheating was estimated from measured microclimate parameters in two similar rooms of the building. This article is devoted to describing methods of measurement and calculation of efficiency of controlled present window blinds in the existing buildings.

Vsevolod Buravchenko, Oleg Sergeychuk, Serhii Kozhedub

Methods of Reinforcing for Engineering Restoration of Architectural Monuments

The article presents the survey results of the architectural monument-St. Alexis Church in Bayramaly (Turkmenistan). The main causes of structural damage have been analyzed. The purpose of the meticulous task was to study the technical condition of the structural elements, establish the causes of damage, evaluate the possibility of eliminating the root cause of the defects and to renovate the historical architectural monument to its original grandeur, with bare minimum changes to the original design and/or structural replacements. The original structural analysis was carried out on the said structures and measures for their recovery were proposed. The article details the path to restoration of monuments and proposes a new approach (method) to reinforcement of walls. This method addresses the problem of development of cracks that appear due to the shearing of walls as a result of uneven foundation soil deformations. This method of reinforcement of walls, allows anchors to work as a dowel joint to withstand high shear force.

Olena Chernieva, Gennadiy Plahotny, Matej Babič

Comparison of Bitumen Modified by Phenol Formaldehyde Resins Synthesized from Different Raw Materials

Phenol formaldehyde resins were obtained by polycondensation of a mixture of phenols (technical or “raw” phenols) obtained from the phenolic fraction of coal tar. The resulting resin approximately consists of 1/3 of phenol and 2/3 of cresols. The obtained resins were compared with industrial phenol formaldehyde resins, the raw material of which is pure (synthetic) phenol. The possibility of using the obtained resins as modifiers of road petroleum bitumen has been established, especially as adhesive promoters to bitumen. It is shown that the addition of these resins significantly increases the adhesion to the surface of granite rubble and glass. Adhesion to the glass surface increases for PhCR-F from 33 to 87%; for Iditol from 33 to 90% and adhesion to the crushed stone surface for PhCR-F from mark 3 to mark 5; for Iditol from mark 3 to mark 5. This indicates that PhCR-F and Iditol can used as adhesive additives for oil road bitumen

Yuriy Demchuk, Volodymyr Gunka, Iurii Sidun, Sergii Solodkyy

The Influence of Concrete Structure on the Destruction of Reinforced Concrete Bended Elements

When ecological effect of the environment on the structural constructions the changing structure of concrete influences definitely on the cracking, bearing capacity and durability. The mechanism of the formation of the composite building materials structure – the concretes with the formation of interfaces on the contact plane, inclusions, and matrix is described. Fine and coarse aggregate are considered as inclusions, and mortar and cement mortar as a matrix. Such a selection of structural levels makes it possible to establish the occurrence of dangerous defects, which size is larger than the size of the constituents of the element’s structure. Therefore, the size of the defect, safe at one structural level, becomes dangerous at a lower level. So a crack that is safe for concrete on large aggregates is destructive for cement stone. The questions of structure formation in concrete and reinforced concrete products on micro - and macro levels are considered.The method of accounting for the initial (technological) damage to the iron reinforced concrete bending elements is presented. The tests of reinforced concrete beams under the action of low-cycle load are made, and their results are presented. The nature of crack formation and the development of cracks under the action of an external load in flexible concrete elements, depending on the technological damage have been established. The crack depth was determined depending on the load, using ultrasonic equipment. It is established that cracks from an external load develop from technological ones, and along their paths.

Dorofeyev Vitaliy, Pushkar Natalia, Zinchenko Hanna

Ukraine Energy Transition in Light of the EU Experience

The results of the analysis of the Ukraine’s starting positions to implement the energy transition from thermal power with fossil carbon-based and nuclear fuels as the main energy resources to low-carbon energy based on alternative, mainly renewable energy sources, are presented. The initial energy-economic conditions of this transition are considered. It is noted that Ukraine has powerful, but morally and physically obsolete energy sector with outdated indicators which do not meet modern requirements for efficiency, environmental friendliness, safety and investment attractiveness. A certain amount of attention is paid to coverage of the starting legislative conditions for the “energy transition” in Ukraine. At the same time, the particular importance of the set of regulatory documents that make up the so-called Fourth Energy Package (“Clean Energy for all Europeans” package) is indicated. Energy transition strategies features of the number of EU member-states (Germany, France, Denmark) are highlighted. The possibility of the presence in the EU member-states of significantly different models of this transition in terms of the use of nuclear generation, various renewable energy sources, etc. is indicated. The rating data of the EU member-states and Ukraine by some energy indicators are given. The analysis of the concept of the “energy transition” in the context of ensuring long-term energy security in the conditions of fulfilling the requirements of SDGs is carried out. It is noted mutual influences and links between the concepts of “energy transition” and “energy security” (at the last case also at the economic and state levels).

Nataliia Fialko, Mykola Tymchenko

Investigation of Preparation Processes of Liquid Feed Mixtures in Rotary Pulsating Apparatus

A new design of the device for preparation of liquid grain feeds using the technology of discrete-pulse energy input is proposed. The essence of this technology is to use in the processing of the feed mixture in the working body, which consists of a rotor having a high speed and a stator with holes for grinding solid components and homogenization of feed when passing through these holes. In the report the experimental research and numerical modeling of processes of hydrodynamics and heat transfer in the rotary-pulsation device at processing of water-grain mix for preparation of liquid grain forages is carried out. The result is the distribution of velocities and temperatures in the channels of the rotor-stator system. It is found that as a result of processing the liquid feed mixture is its homogenization and heating due to the conversion of the kinetic energy of rotation of the rotor into heat energy. An experimental study of the preparation processes of liquid feed mixture in a rotary pulsation apparatus was carried out. The composition and temperature characteristics of feed mixture were studied. The results of numerical simulation are compared with experimental data.

Valery Gorobets, Viktor Trokhaniak, Ievgen Antypov, Andrii Serdiuk

Investigations of Compact Recuperators Acoustic Properties

The article is devoted to solving the urgent task of increasing the efficiency of air distribution in a room. The aim of this work is the investigation of Prana recuperator acoustic properties at air jets leakage, which flow out from outlets under varying conditions. In this article relationship between such factors as a noise level, sound frequency and the different noise decrease measures at Prana recuperator action in a room has been determined. There are considered some sources of noise: Prana recuperator action, noise in a room and outside and aerodynamic noise of the air jet flowing out from the outlet. There have been designed the charts of sound level difference dependence from the sound’s frequency and noise level. Obtained curves were approximated by equations. Comparing charts for the different noise decrease measures at Prana recuperator action in a room, we shall note that noise level difference is the highest at using of the cover device. Installation of the Prana recuperator does not impair the sound-proofing ability of the structure to the air noise of traffic flows, and the installation in front of the Prana of acoustic screens does not give a tangible result.

Bohdan Gulay, Iryna Sukholova, Oleksandra Dzeryn, Volodymyr Shepitchak

Effect of Nano-TiO2 and ETS Antifungal Agent Addition on the Mechanical and Biocidal Properties of Cement Mortars

The scope of the study is to test the influence of nano-TiO2 and ETS biocide addition on the mechanical and fungicidal properties of cement mortars. It is shown that the use of doped titanium dioxide and thiosulphanate structure modifier of the antifungal agent ETS is one of the ways to obtain an effective composite antifungal additive to cement mortars. The possibility of developing such complex additives to achieve a synergistic effect in the field of fungicidal coatings has been investigated. The use of nanosized doped titanium dioxide creates a photocatalytic layer on the surface of the material, which is activated by UV or visible light, while the biocide ETS modifier works in the dark, also extending the spectrum of action to other living organisms. Modified with such an additive, cement mortar became 19% stronger than the control sample. The change of the surface microstructure, the appearance of a significant number of mesopores and macropores, which creates a larger surface, thus increasing the photocatalytic activity, was confirmed. A comparison of the growth of mold colonies on control and modified samples is shown.

Marko Hohol, Vira Lubenets, Olena Komarovska-Porokhnyavets, Myroslav Sanytsky

Non-uniformity of Water Inflow into Pressure Collector-Pipeline Depending on the Values of Reynolds Criterion and of Inflow Jets Angles

Results of experimental investigation of the influence of Reynolds criterium $$ Re_{D} $$ on the non-uniformity in the work of pressure collector-pipeline (CPs) for different values of the angle $$ \beta $$ of jet inflow into the fluid stream in CP are presented. The angle $$ \beta $$ was assigned the following values: $$ 0^{o} $$ ; $$ 4 5^{o} $$ ; $$ 9 0^{o} $$ ; $$ 1 3 5^{o} $$ ; $$ 1 8 0^{o} $$ . The value of Reynolds criterion $$ Re_{D} $$ was varied within the range from 5211 to 28321. In has been found that the non-uniformity of distribution of the working heads in the CP and those of water inflow into the CP along the path decreased with the increase in the Reynolds criterion $$ Re_{D} $$ . By means of variation of the values of the angle $$ \beta $$ , the reduction of non-uniformity of the working heads distribution along the CP was achieved up to 44.49%, and that of water inflow into the CP along the path up to 9.07% (as compared to the case of orthogonal jet inflow into the main stream of collector-pipeline).

Vasyl Ivaniv, Volodymyr Cherniuk, Vasyl Kochkodan

Examining the Interdependence of the Various Parameters of Indoor Air

In this paper, the partial results of the investigation of the interrelationship of individual parameters of indoor air - temperature, relative humidity and CO2 concentration, obtained during the experimental measurement, are presented. The experimental measurements have been performed in a selected room, where three separate lessons with three different groups of people have been conducted. During these measurements, the processes of temperature, relative humidity and CO2 concentration have been recorded. Also, people involved in this investigation have made their own evaluation. They, have been asked for opinion about the internal air quality at the beginning and at the end of the experimental measurement.

Peter Kapalo, Maria Sulewska, Mariusz Adamski

The Analysis of Heat Consumption in the Selected City

The higher standard of living, the longer time of stay in buildings, the higher requirements for the creation of the internal environment of buildings using technical equipment of buildings and the climate change on the planet and the climate change on the planet are causing an increase in energy consumption in buildings. One of the reduction options is to thermal insulation buildings with an optimized thickness of thermal insulation. Before measures is need to take consider the building is used, the properties of building materials, the climatic conditions of country, the rate of use of renewable energy sources, the standard of modernization of the system of remote energy supply of buildings, the standard of automatic control of technological equipment points and mainly return on investment, especially in older buildings. So far, the most effective measure in order to reduce the energy intensity of the whole system is thermal insulation of buildings. In city settlements, it is possible to insulate individual buildings in successive steps, which allows the input investment costs to be decompose over several years. In this article is documented the results of energy consumption of buildings in a selected city, where there is a gradually thermal insulation of buildings. The put emphasis is on for heat consumption for heating and hot water.

Peter Kapalo, Mariusz Adamski

Assessment of Thermal Insulation Properties of Envelope Structures of a Burgher House in Kosice

The article presents a basic overview of the most frequently used and proven interventions in historic buildings, focusing on the details of a burgher house in Kosice. In the case of renovation and reconstruction of an old building, it is necessary to take into account specific facts. A normal building is approached differently and a building that has historical value is different. The Energy Efficiency Act exempts historic buildings from certification. Not all old historic buildings are subject to monument protection. Methods of covert isolation that preserves the authenticity of cultural monuments and real estate in monument areas are a current challenge of heritage practices. The sustainability of the operation of historic buildings ultimately means the preservation and appropriate use of the heritage fund. The list of interventions that do not endanger the monumental values or use of the building is gradually expanding. This is mainly due to modern, increasingly sophisticated materials and technologies that are coming into practice.

Dusan Katunsky, Jana Katunska

Performance Analysis of the Small-Scale Refrigeration System Using Natural Refrigerants and Their Mixtures

Refrigeration system holds an important role in many commercial and household applications The optimal utilization of energy saving technologies in commercial and household refrigeration systems is a key issue for the rational use of energy resources. The scope of this study is an experimantal analysis of the small-scale refrigeration system efficiency using HFC, hydrocarbons and their mixtures as the most promising working substances in terms of environmental indicators. For analysis purposes were selected refrigerants R32, R152a and R134a in combination with hydrocarbons R600a and R290. Based on analysis results, it was concluded that the targeted modification of ozone-safe refrigerants based on synthetic refrigerants with natural hydrocarbon components is an effective means of creating a new class of alternative azeotropic working fluids in refrigeration technology.

Mykhailo Khmelniuk, Oleksii Ostapenko, Olga Yakovleva

The Probabilistic Calculation Model of RC Beams, Strengthened by RC Jacket

According to the engineering method of calculation of normal cross section of reinforce concrete beam with use of the basic concepts of probability theory and random function theory, is proposed the probabilistic calculation model of rectangular reinforce concrete beams, strengthened by reinforce concrete jacket under loading. Real-operating conditions of the considered structures are modeled. Therefore, in calculation theory was included number of controlled random parameters, namely: strength of materials (concrete and steel rebar), geometric parameters of a cross section (before and after strengthening),and also the level of load at the moment of strengthening. Developed model was tested, based on the data of previous experimental studies of the stress-strain state of reinforce concrete beams’ series, strengthened by reinforce concrete jacket under loading – the values their corresponding qualitative and quantitative reliability indixes (reliability indexes β and probabilities of failure Q(β), respectively) are obtained. Analysis of the obtained results was also made.

Roman Khmil, Roman Tytarenko, Yaroslav Blikharskyy, Pavlo Vegera

Operation of Damaged H-Shaped Columns

During the research, the main causes and consequences of damage to reinforced concrete eccentrically compressed structures of the H-shaped cross-section were established Three main factors that affect the value of the residual bearing capacity of the elements are identified. A three-level three-factor Boks-Benkin plan has been created, which will give statistically substantiated results (within the variation of variable factors) in the research of only 15 experimental columns. Samples of compressed elements were made and tested (according to the experimental plan). As a result of the experiments, data were obtained that allowed to describe the stress-strain state of the damaged H-shaped reinforced concrete columns. The dependences of stresses in reinforcement and relative deformations in concrete on the parameters of damage and load level are obtained. Based on the analysis of scientific proposals and the stress-strain state obtained experimentally, the basic preconditions for calculating the residual bearing capacity of elements damaged during operation of structures are adopted. A system of equations is developed, as a result of the solution of which the value of the residual capacity of the damaged columns is obtained. A system of equations is created and the ways of its solution are planned. Proposals for determining the residual bearing capacity of damaged reinforced concrete compressed columns are based on the main provisions of current regulations and extends their effect to damaged structures of the most common cross section – H-shaped.

Yevhenii Klymenko, Zeljko Kos, Iryna Grynyova, Olena Maksiuta

Designing of Standard Cross Sections of Composite Bending Reinforced Concrete Elements by the Method of Design Resistance of Reinforced Concrete

The principles of designing standard cross sections of composite bending reinforced concrete elements using modern deformation models have been considered in the proposed article. This paper is dedicated to composite beams with symmetrical cross sections, which are most frequently used in practical activity in construction sphere. In such elements there are neither torsion, nor tension in perpendicular plane of effect of forces, thanks to which they have the highest loading-carrying ability as compared to asymmetrical composite constructions. The authors have developed an alternative calculation method for the composite bending elements by using the method of analysis of design resistance of reinforced concrete. The given method makes it quite easy to make calculations of such elements, concurrently its precision corresponds to the accuracy of calculation of modern deformation models, taking into account nonlinear deformation curves of materials. The procedure for calculating three types of problems, which are typically used in construction practice, has been proposed in this research work. This article presents the procedure of calculation of the following problems: determination of the required area of reinforcing steel according to the known size dimensions of composite beams and defined strength grade of materials; determination of the bearing capacity of standard cross sections with known reinforcement; checking procedure of the bearing capacity of composite bending elements. An example of calculation of standard cross sections of composite bending reinforced concrete elements made of different concrete grades.

Dmitro Kochkarev, Taliat Azizov, Anna Azizova, Tatiana Galinska

Promising Trends in Design of LED Lighting Combined with Systems of Natural Lighting

The article deals with promising trends in LED lighting design combined with daylight systems. In the process of research such methods as analysis, synthesis, generalization, visual and graphic modeling, and scientific observation were applied. The article characterizes the features of combined lighting and its main conventional schemes, as well as analyzes modern examples of combining LED lighting with the daylight systems. It has been discovered that the adjustment of natural and artificial lighting systems can be secured by the combination of their elements, by the addition of luminous flux from artificial sources to solar radiation (combined lighting), or by the combinations of these two schemes. The research has enabled to point out the absence of the modern examples of the structural combination of LED lighting with the most common systems of lateral daylight lighting used in the apartment buildings. A relevant project proposal of the autonomous lighting system, made on the basis of solar batteries and LED light sources, has been made. The study is both theoretical and applied, it may be used when preparing design proposals and for creating light environment of various premises.

Lidiia Koval, Volodymyr Yehorchenkov, Viacheslav Martynov

Influence of Basalt Fiber Dispersed Reinforcement on the Work of Concrete Beams with Non-metallic Composite Reinforcement

Recently, non-metallic composite reinforcement has been used more frequently to reinforce concrete beam structures. It has a number of advantages in comparison with steel: much greater tensile strength, high corrosion resistance, low weight, dielectric constant. However, non-metallic composite reinforcement has a lower elasticity compared to steel, and beams reinforced with non-metallic composite reinforcement have worse characteristics of deformability and crack resistance. To improve these characteristics, dispersed basalt fiber reinforcement of concrete beams with non-metallic composite reinforcement has been proposed, the effectiveness of which has been proven experimentally. The test specimens were beams with a cross section of 100 × 200 mm and a length of 2100 mm, which were made of laboratory-made concrete. The basic reinforcement of each of the beams was one rod of working basalt-plastic reinforcement type ANPB with length of 2080 mm (diameter varied in series: 4, 6, 8, 10, 12 or 13 mm). The beams were tested on a power bench according to the scheme of pure bending – two concentrated forces located in the thirds of the run, transmitting the load from the hydraulic jack.

Petro Koval, Maksym Koval, Yaroslav Balabukh, Oleh Hrymak

Strength of Reinforced Concrete Beams Strengthened Under Loading with Additional Reinforcement with Different Levels of its Pre-tension

This article describes the strengthening of normal sections of reinforced concrete beams by pre-stressed reinforcement under load. Experimental samples had the length of 2100 mm, the width of 100 mm and the height of 200 mm. Strengthening of experimental beams is designed from flat frames and isolated rods, which were combined into a spatial frame by transverse rods. In all the be the longitudinal working reinforcement were steel bars of 2 2 Ø 12 A500C, constructive and transverse reinforcement was represented by– Ø 8 A240C bars with spacing of 50…100 mm. The load was applied by means of a hydraulic jack in thirds of the span. The beams were tested for bending. The beams were reinforced with the use of two unstressed or pre-stressed reinforcement rods of Ø12 A500C mm.Their connection to the main beam reinforcement by welding through Ø28 mm reinforcement rods. Three series of beams were tested: the first one consisted of two beams of the VO series, the second –of two beams reinforced with unstressed reinforcement at the level of 0.7Mcr (beams of the BR series), the third - beams reinforced with pre-stressed reinforcement at the level of 0.7Mcr (beams of the BRR series) with additional reinforcement tension level of 70% and 90%. The effect of beam reinforcement, at the level of 0.7Mcr, by additional reinforcement without its pre-stressing was 49%, and with the use of pre-stressing of additional reinforcement - 108% and 118%, respectively.

Bogdan Kovalchuk, Yaroslav Blikharskyy, Jacek Selejdak, Zinoviy Blikharskyy

Effects of Nano-liquids on the Durability of Brick Constructions for External Walls

The effectiveness of the influence of modifying substances on the properties of ceramic facing brick and masonry surface for decorative external walls is considered in the article. X-ray diffraction and spectral analysis showed that sodium sulfate, potassium sulfate and syngenite are the salt effloresces from the ceramic brick surface. It is established that polymeric one-component coatings based on siloxanes are not effective, especially under the action of alternating temperatures. Studies have shown that the improvement of the performance properties of ceramic facing brick increase due to the surface coating by nano-liquids with the addition of nano-Al2O3. The surface modification of the ceramic facing brick by hydrophobic nano-liquids allows sealing the structure due to the colmatation of pores, which reduces the capillary tightening of the masonry. It also leads to increased weather resistance and frost resistance of masonry. It is established that the surface protection of brick structures with hydrophobic nano substances provides a decrease in the porosity, increase the water resistance and durability. This allows to confirm the relevance of the revealed influence of the modifiers on the formation of properties and the practical attractiveness of the proposed technological solutions.

Tetiana Kropyvnytska, Roksolana Semeniv, Roman Kotiv, Yurii Novytskyi

Monitoring of Dynamic Loads on Steel Headframes

According to the regulatory requirements of Ukraine, structures of headframes belong to CC-3 importance class. Such a regulatory requirement as systems for safety monitoring of a technical state is available for the constructions of CC-3 importance class. Dynamic strain loads resulting from the hoist rope tension is the basic type of technological loads; their monitoring is of principal importance to evaluate their operational safety. Following theoretical and experimental methods have been applied to substantiate a system to monitor loads on a headframe structure: finite-element method; tensometric method for strain measurement; and method of experiment planning. Relying upon the generalized results of theoretical and experimental research concerning regularities of distribution of local stresses within the bearing support pulleys, the paper proposes a principle of tensiometer allocation agreed with the methods determining hoist rope tension based upon a mathematical model developed by the authors. The proposed method to monitor dynamic loads resulting from tension of hoist ropes makes it possible to record intermittent (emergency) loads as well as load cycles of normal service. The abovementioned helps evaluate structural fatigue strength of a mine headframe structure as well as the mine hoist components.

Volodymir Kushchenko, Oleksandr Nechytailo

Dependence of Evaporation Temperature and Exergetic Efficiency of Air Split-Conditioners Heat Pumps from the External Air Temperature

In the face of growing shortages and rising prices for fuel and energy resources, the problem of energy conservation and the use of alternative energy sources to solve the problem of reducing energy consumption for the Ukrainian economy becomes very important. Today, the use of air split-conditioner heat pumps in buildings’ heating systems is becoming more common. Therefore, the improvement of the design and operation of power equipment to which air split-conditioner heat pumps (“air-air”) are related, is related to a detailed study of their operation and an objective assessment of their degree of energy perfection, which can only be determined on the basis of analysis their exergy efficiency. This made it possible to substantiate the relevance of such a research task due to the lack of information on the operating modes and the exergy efficiency of the use of air split-conditioner heat pumps. It was used the author’s innovation, the mathematical model to analysis of the operation of one-step freon heat pumps, which are used in air split-conditioners according to the exergetic method. The dependence of the evaporation temperature and the exergetic output-input ratio (OIR) of the air split-conditioner heat pump by “Mitsubishi Electric” firm with nominal heating capacity of 3067 W in the standard external temperature conditions on the refrigerant R32, was determined from the out of doors temperature.

Volodymyr Labay, Vitaliy Yaroslav, Oleksandr Dovbush, Bohdan Piznak

Influence of Damages in the Compressed Zone on Bearing Capacity of Reinforced Concrete Beams

The paper present the results of reinforce concrete beams damaged at compressed fiber. Study of damaged reinforced concrete elements is associated with certain complexity in both theoretical and practical issues. In such cases the number of factors take place which influence on elements’ performance, which is caused by composite features of reinforced concrete elements. In addition certain factors occur due to damages. In the article experimental data is analyzed concerning concrete damages’ influence in the compressed zone on the bearing capacity of the reinforced concrete elements. Results of 4 reinforced concrete beams’ testing are proposed one of which was the control one (tested without damages) and three,- typically damaged in compressed zone at different load levels. As the result the effect of damage and load influence on bearing capacity of beams was indicated, as well as effect of neutral axis position change. Research results demonstrate increase of 3.8% in reinforced concrete beams bearing capacity, if they are damaged under the load, comparing with the unloaded damaged reinforced concrete beams.

Maxim Lobodanov, Pavlo Vegera, Roman Khmil, Zinoviy Blikharskyy

Influence of Humidity of Wood Fuel on the Gasification Process in a Continuous Layer

In the world has been stepped up the work to develop technologies for biomass thermal conversion into gaseous fuels that can be used for combustion in different types of boilers, in internal combustion engines, or for liquefaction. The main advantage of the biomass thermal conversion technology for synthesis gas is its low environmental impact compared to fossil fuels. Therefore, gasification is one of the most promising ways of converting wood fuel into energy. According to the results of experimental research, the regression dependence of the lower calorific heat of synthesis gas during thermal processing of wood into gaseous fuel was obtained from the relative humidity and fractional composition of wood, the amount of air fed into the gasification chamber. Were found the rational values of humidity and fractional composition of the wood, as well as the amount of air supplied to the gasification chamber, at which the lower calorific heat of the synthesis gas reaches the maximum.

Stepan Lys, Oksana Yurasova, Yuriy Vashkurak

Experimental Study of Crack Resistance and Shear Strength of Single-Span Reinforced Concrete Beams Under a Concentrated Load at a/d = 1

At a stage following the crack development, a reinforced concrete beam has a complex structure that does not correspond to such simple systems as the truss, arch or strutted frame. Therefore, to establish a possible design model for calculating the shear strength, it is necessary to know not only the failure pattern, but also the order of crack nucleation and propagation in the loaded structures. The pattern of nucleation and propagation of diagonal cracks differs significantly from that of vertical cracks, which are the reason for the stretching stress or bending moment. Diagonal cracks can be far more dangerous, as the time interval between the crack nucleation and failure is considerably shorter than for pure bending. The paper discusses the experimental study of diagonal cross-sections of single-span reinforced concrete beams under a concentrated load for a/d = 1. The tested beams had identical characteristics and differed only in the type of transverse reinforcement. The analysis of the experimental data revealed the specifics of nucleation and propagation of diagonal cracks in the zone of impact of the shear force and bending moment. The dynamics of propagation and width of diagonal cracks opening was recorded depending on the load. The effect of different types of transverse reinforcement on the bearing capacity of the beams was established.

Solomiya Maksymovych, Olha Krochak, Ihor Karkhut, Rostyslav Vashkevych

Effect of Plasticizing and Retarding Admixtures on the Properties of High Strength Concrete

From year to year the Earth’s temperature increases due to global warming resulting in new challenges in the concrete industry. It still remains very important branch of the modern economy. Concrete is the material which is used widely. Due to the temperature rising, the transportation of fresh concrete in hot weather becomes complicated, especially high strength concrete, which contains higher amount of cement in comparison with traditional concrete. In spite of this the fresh concrete should be delivered in plastic state to provide proper placing and compaction. That’s why it is compulsory to use retarders and plasticizers if high strength concrete is designed. In this article the influence of plasticizers and retarder on properties of cement paste, fresh and hardened concrete was studied, because it is important to enhance the workability and slump retention of such concrete under hot weather. The setting time and compressive strength of cement paste with different dosages of polycarboxylate and lignosulphonate based plasticizers with retarding effect and retarder on the basis of sodium gluconate (SG) were studied. Experimental researches were carried out to determine the optimum dosage of plasticizing and retarding admixtures and their effect on compressive strength of concretes. The influence of optimal amount of polycarboxylate based plasticizer and SG on slump loss and compressive strength of concrete was established as well. The obtained results show that correlation between setting time of cement paste and slump loss isn’t observed, but rational technical decisions allow to obtain designed properties both fresh and hardened concretes.

Taras Markiv, Sergii Solodkyy, Khrystyna Sobol, Djire Rachidi

Analysis of the Water Consumption in the Apartment House – Case Study

The aim of the research is to analyze the water demand in apartment building calculated according to the state regulations of Poland, Czech Republic, Romania, Slovak Republic and Ukraine and to compare them with the results of experimental measurements in apartment building. Poland and the Czech Republic are characterized by the minimum average coefficient of water demand for residents of the houses with local hot water preparation. For Romania, Slovak Republic and Ukraine this value is higher by 20, 35 and 110–135% respectively. Czech Republic has the lowest values of theoretically calculated daily (minimum, average and maximum) water demand. These values are higher for Romania – by 38.9, 15.3 and 9.7%; Slovak Republic – by 35.2, 34.7 and 34.9%; Ukraine – by 114.8, 101.4 and 109.6% respectively, as compared with water demand in Czech Republic. The average daily water consumption in an apartment building, measured experimentally, corresponds to the normative value of the specific water demand adopted in the Czech Republic. Maximum daily water demand exceeds the estimated value and corresponds to the maximum coefficient of the daily variation in water demand, which equals 1.63.

Oksana Matsiyevska, Peter Kapalo, Jakub Vrana, Cristina Iacob

Precise Explicit Approximations of the Colebrook-White Equation for Engineering Systems

Modern automated engineering systems have variable hydraulic/aerodynamic conditions with Reynolds number from zero to hundred thousand with a wide range of roughness. Simple approximations of the Colebrook-White equation cannot give enough precision. The aim of the work is a universal simple precise approximation of the Colebrook-White equation. The methods are selected by the analysis of the equation curve. In the whole range of turbulent flow, it is near to linear. Thus, Newton’s method is very effective. The algorithm is proposed for getting high-precision approximations. The results are two simple explicit ones for rough and careful calculations with a deviation of 5.36% and 0.00072% in a wide range of parameters. It is shown on the examples of the objects: the highest building “Biotecton” and researches of “green roofs” in a wind tunnel. The scientific novelty is that we scientifically grounded the effective usage of Newton’s method, which provides new universal, precise and simple explicit approximations of Colebrook-White equation. The practical value is that the approximations are covered different practical tasks of hydraulic and aerodynamic calculations in the whole range of turbulent flow.

Viktor Mileikovskyi, Tetiana Tkachenko

Technical and Economic Efficiency After the Boiler Room Renewal

The article is devoted to decision of actual task of energy saving. As a fact, a large-scale energy saving policy is being implemented in Ukraine, and energy efficiency objectives are comprehensive and cover both the legislative framework and technical innovations. It is consumed in the boiler rooms too much amount of gas. One of the effective ways to reduce energy consumption for boiler gas supply is to carry out the thermal modernization of the boiler rooms. This article describes the economic indicators of thermal renovation measures during the reconstruction of the boiler rooms. During the reconstruction of boiler rooms the following thermal modernization measures were taken for comparison: equipping the existing boiler with a modern domestic gas burner, economizer or condensing economizer; replacement of the existing boiler with a modern Ukrainian-made boiler with a modern domestic burner with the possibility of its additional equipping with economizer or condensing economizer; replacement of the existing boiler by Viessmann boiler. Conducted energy audit of the boiler room during its reconstruction has showed that the profit from the introduction of energy-saving technologies during their operation is the maximum, if it is provided the modernization of the existing boiler by its equipment at the same time modern burner domestic production and condensing economizer.

Khrystyna Myroniuk, Orest Voznyak, Yuriy Yurkevych, Bohdan Gulay

The Calculation of Indoor Air Forecast Temperature of a Space with the Replaceable Thermotechnical Characteristics of the Enclosure Structures While in Operation

In this article there are given the calculations of indoor air forecast temperature of a space, having the outer enclosure structures with the replaceable thermotechnical characteristics of structural layers while in operation. The indoor temperature forecasting is an interesting and actual task, which makes it possible to solve problems related to the process of ensuring the parameters of the indoor microclimate, as well as social. The solving of this task depends on many factors influencing the maintenance of a stable indoor air temperature. The one-dimensional thermal field in a flat wall with a fixed heat transfer process between warm and cold air, which have constant temperatures and processes of internal destruction of building materials is considered as a basis for solving this task. The solution of the problem involves determining the coefficient of heat transfer, or the thermal resistance of the outer wall under conditions of their variation in operation and the final determination of the indoor air forecasting temperature. The derivation of an equation of determination of the indoor air forecasting temperature is based on the assumption that the heating losses of the room are equal to heat inputs of the heating appliances/unit heaters of the heating system. As a result, the equation of determination of the indoor air forecasting temperature subject to alterations of thermotechnical characteristics of structural layers and the enclosing parts is obtained.

Viktor Petrenko, Konstantin Dikarev, Anatolii Petrenko, Ruslan Papirnyk

Hydration Products that Provide Water-Repellency for Portland Cement-Based Waterproofing Compositions and Their Identification by Physical and Chemical Methods

The coatings formed by water-proofing compositions of a penetrating action are characterized by high physical and mechanical properties and good adhesion to the substrates used for their deposition. The experimental investigations of the influence multicomponent chemical additive that provide waterproofness on the formation of the hydration products of Portland cement have been carried out. The colmatation of the pores and capillaries by the hydration products of Portland cement with the complex chemical additive were simulated. Such pores were simulated by the formation of the cement-perlite mortar and the capillaries were simulated by the introduction of fiberglass to the cement paste. The data of X-ray phase analysis, infrared spectroscopy, and thermal analysis show the formation of carbonate and chloride AFm-phases and possibly the formation of the nitrate AFm-phase and calcite in the cement stone with the complex chemical additive. The data of electron microscopy research also showed that the hydration of Portland cement with complex chemical additive results in the formation of crystallohydrates that according to their morphological features can be identified as carbonate-, chloride-, and nitrate AFm-phases, portlandite, and calcite that grow on silicate surfaces with a negative surface charge.

Andrii A. Plugin, Olga S. Borziak, Oleksii A. Pluhin, Tatiana A. Kostuk, Dmytro A. Plugin

Humidity, Air Temperature, CO2 and Well-Being of People with and Without Green Wall

The paper presents an experiment on green wall performed to apprehend its thermal and hydrological behavior and its impact inside building. The experiment is based on a living wall set up in a classroom of the faculty in TUKE campus in Košice where the interior green wall is situated. Monitoring of temperature, humidity and CO2 variations within the living wall and a reference case enable us to analyze effects of green walls. During the measurements, set of questions were answered. The data of respondents are used for gaining the goal of this interdisciplinary research, the effect of green wall on the well-being of people. The measurements were carried out in the classroom between January 04, 2018 and February 08, 2018. It can be stated that women are more sensitive to changes than men. Following the measurements, the green wall is very favorable for the indoor environment.

Zuzana Poorova, Zuzana Vranayova

Production of Fly Ash Aerated Concrete and Efficiency of Its Application

The literature sources on the production and energy efficiency of non-autoclaved aerated concrete application are analyzed. The efficiency of use in the composition of aerated concrete as a filler of fly ash and light microsphere (cenosphere) is compared. It is shown that at the same content of source materials the use of fly ash as a filler allows us to obtain aerated concrete with an average density of 969 kg/m3 and a strength of 3.5 MPa. Substituting the fly ash in aerated concrete composition makes it possible to reduce its average density to 440 kg/m3 with a strength of 1.14 MPa. The pore structure of the aerated concrete samples is investigated. The complex estimation of the efficiency using the developed fly ash aerated concrete in the construction of the enclosing structures of residential buildings is made. The efficiency is evaluated taking into account the costs (including the energy component) at different stages of the life cycle of the building: production, construction, operation. Selection of individual elements and the optimal design of the external enclosure of the building, based on the proposed indicator of the cost of unit saving energy, and with account of the cost of construction and installation works and operational characteristics of individual elements, is performed.

Oksana Pozniak, Volodymyr Melnyk, Igor Margal, Petro Novosad

Analysis of the Current Methodology Disadvantage of the Consumed Thermal Energy Allocation Between Consumers for Heating of Multi-apartment Buildings and Ways of its Improvement

The paper analyzes the current “Methodology of the consumed utilities allocation between consumers in the building” (hereinafter - Methodology) in the section of determining the consumed thermal energy for heating. The analysis shows the disadvantages of the current Methodology in the section of determining the consumed thermal energy allocation between consumers for heating of multi-apartment buildings. Such disadvantages are already confirmed by the initial experience of applying this Methodology into practice. The differences between the current Methodology and the Methodology developed by the National University of Water and Environmental Engineering (NUWEE) “Methodology of the consumed thermal energy calculating for common areas heating of multi-apartment buildings”, namely the calculating principles of the thermal energy for heating of common areas and additional spaces of the building, minimum heat consumption in the heated space and etc. The analysis is given of the Methodology algorithm of heat energy allocation between consumers in those houses where the individual accounting of heat consumption for heating is organized by installing heat cost allocators on the heating units, which describes the disadvantages of the absence of the radiator coefficients’ use. The current Methodology should be improved taking into account the above analysis using the approaches proposed by the authors, which are described in the developed methodology of the NUWEE.

Serhii Protsenko, Mykola Kizyeyev, Olha Novytska, Nataliia Kravchenko

Impact of Undular Jump Characteristics on Erosion of Tailrace Channel

The aim of article is to develop the method of calculating the free-surface profile of undular jump for correct evaluation of its characteristics influence on tailrace channel erosion. The research method is based on using the differential equations of wavelike near-critical flows free-surface profile with taking into account the possible non-hydrostatics in their initial cross-section, energy losses and wave attenuation along the length. The different methods of calculating the free-surface profile of undular jump were analyzed. It was paid special attention to consider this phenomenon as combination of solitary wave and cnoidal waves. The article emphasized the results of undular jump experimental researches which were made by authors on different laboratory setups. The comparison of theoretical and experimental data showed their good convergence and confirmed the conceptual correctness of developed method. The scientific novelty is taking into account total important factors such as possible deviation from hydrostatics in the initial cross-section, energy losses and wave attenuation along the length. The practice value is determining the length of wave attenuation that is needed to accept the length of tailrace channel paving.

Oleksandr Riabenko, Oksana Kliukha, Oksana Halych, Dmytro Poplavskyi

Influence of Flexibility of Bolted Joints on Rigity of the Hingeless Frame

The article investigates the influence of the flexibility of the rigid node of connection of the crossbar with the frame rack on the stress-strain state of the elements under the action of vertical evenly distributed load on the crossbar and horizontal evenly distributed load, applied to the frame racks. Since the bolts in the flange connection are stretched by the action of the bending moment, the nodes open, that is become partially hinged. Knowing some initial parameters of ideally rigid knots, it is possible to establish, what influence their change will have, both on the design scheme of a frame as a whole, and on its separate elements. The initial parameter method was used to determine the influence of the flange opening angles on the stress state of the elements. The proposed method allows us to determine the rigidity of any bolted flange connection, taking into account its actual operation. Taking into account the pliability of the nodes and, as a consequence, the structure as a whole, allows us to unload the elements and calculate the additional resource bearing capacity. In addition, the technique allows you to adjust the stiffness of the bolted joint by changing the diameter of the bolts, their number, distance between them or changing the thickness and height of the flanges, as well as use additional material resource by reducing the maximum stresses in the calculated cross sections.

Volodymyr Romaniuk, Volodymyr Supruniuk

The Effect of Mechanical Activation on the Properties of Hardened Portland Cement

The results of mechanical activation effect using vibro-milling on the properties of hardened Portland cement were presented. Comprehensive assessment of particle size distribution by volume and surface area of ordinary and activated Portland cement was carried out. The heat of hydration, initial and final setting times of the cement pastes, rheological properties and strength development of cement mortars were determined. The calorimetric data reveal that mechanical activation of ordinary Portland cement causes sharp increasing of heat hydration rate and the interaction at the boundaries of the “solid-liquid” intensifies at early hydration period as well as setting time reduction is observed. The research of workability and strength kinetics of mechanically activated Portland cement, modified with polycarboxylate superplasticizer are carried out. Modified mechanically activated Portland cement is characterized by early strength development (Rc2/Rc28 = 0.74) as well as standard strength (Rc28 = 59.6 MPa), which meet the requirements of rapid hardening high strength binders.

Myroslav Sanytsky, Alexandr Usherov-Marshak, Uliana Marushchak, Alexey Kabus

Thermal Renewal of Industrial Buildings Gas Supply System

An important priority of the economic policy of Ukraine is the careful use of energy The article is devoted to decision of actual task of energy saving. Therefore, now a large-scale energy saving policy is being implemented in Ukraine, and energy efficiency objectives are comprehensive and cover both the legislative framework and technical innovations. The goal of the paper is to establish economic indicators of thermal renovation measures during the reconstruction of the gas supply system of the industrial buildings at condition of discount rate different magnitudes. It is consumed in the industrial buildings too much amount of gas. One of the effective ways to reduce energy consumption for boiler gas supply is to carry out the thermal modernization of the gas supply system. This article describes the economic indicators of thermal renovation measures during the reconstruction of the gas supply system of the industrial buildings. During the reconstruction of, the following thermal modernization measures were taken for comparison: installation of an energy separator, reconstruction of the gas supply system, and installation of automatics.

Olena Savchenko, Orest Voznyak, Khrystyna Myroniuk, Oleksandr Dovbush

The Sustainable Design of the Greenhouse by Criteria of Heat Losses and Solar Heat Gains

The efficiency of greenhouse design is its ability to receive and accumulate heat from solar radiation. Lots of factors affect the efficiency of greenhouse. One of the main factors is the shape of the greenhouse. The greenhouse shape affects the amount of solar heat gain that received the greenhouse and the amount of heat losses during cold season. The purpose of this research is to determine the optimal shape of greenhouse by the criteria of solar heat gain and heat losses through the covering to reduce total energy consumption and improve energy efficiency of the greenhouse. The five most commonly used greenhouse shapes were considered. In order to determine the optimal shape of energy efficient greenhouse the calculations of the total solar heat gain during the year and heat losses during the cold period (October-April) for the five most common shapes of greenhouses were made. The comparison of solar heat gains and heat losses through enclosing constructions of greenhouses was made.

Mykola Savytskiy, Maryna Bordun, Vitalii Spyrydonenkov

Clarification of Thermal Characteristics of the Solar Collector Integrated into Transparent Facade

The article focuses on current issues and the state of development of energy-efficient construction. The paper notes the need to implement alternative technological solutions in energy-efficient buildings. The need to improve the design of solar collectors integrated into transparent facades of buildings is analyzed. Also, the article proposes and studies an experimental design of a solar collector integrated into the transparent facade of the building. Data on the thermal characteristics of the proposed solar collector integrated into the transparent facade of the building are presented. The article analyzes the effect of simulated solar radiation on the process of heating the heat carrier in the mode of natural circulation in the solar heat supply system. The results obtained allow us to establish the thermal efficiency of the transparent facade integrated into the structure. It is established that the efficiency of the solar heating supply system in the mode of natural circulation of the heat carrier under the intensity 300 W/m2 average 26%, and under the intensity 900 W/m2–64%.

Stepan Shapoval, Iryna Venhryn, Khrystyna Kozak, Hanna Klymenko

Determination of the Charring Rate of Timber to Estimate the Fire Resistance of Structures at Real Temperature Modes of Fires

The article presents the results of researches of fire resistance of timber structures, taking into account the realistic temperature modes of fires. The proposed method of determining the charring rate is based on the main parameters of fire spread that are taken into account in the calculations, based on the analysis of the heating temperature of unprotected elements of timber structures, where an approach on solving an time-dependant equation of thermal conductivity is used. The research of the influence of the depth of the charring on the limit of fire resistance depends to a lesser extent on the coefficient of slots but to a greater extent it depends on the density of the fire load. Thus, the difference for the beam with a cross section of 150 × 300 was 15 min under varying density of the fire load, and for different slot coefficients it is not more than 5 min. Provided that the density of the fire load is less than 690 MJ/m2 for a beam with a cross section of 150 × 300, the limit of fire resistance does not occur at all. The proposed method allows more accurate determining of the limit of fire resistance of timber structures as it takes into account both the main parameters of fire spread and thermal-physical characteristics of the timber.

Taras Shnal, Serhii Pozdieiev, Stanislav Sidnei, Andrii Shvydenko

Development of a Mathematical Model of Fire Spreading in a Three-Storey Building Under Full-Scale Fire-Response Tests

The purpose of the work was to develop a mathematical model of fire spreading in a three-story building during full-scale fire-response tests; research of accuracy and reliability of parameters of temperature modes of fire in separate premises of the building. The Pyrosim computer system, a user shell for the Fire Dynamics Simulator program, was used to calculate the temperature in the models of premises under fire. A numerical experiment was conducted to model full-scale tests of premises with fire in a three-story building using computer gas-hydrodynamics methods. The nature of the fire development and the time dependences of its main parameters were revealed, which in turn allowed analyzing the adequacy of the modelling results and investigating their adequacy and accuracy. The obtained results of the research on the accuracy of modeling the full-scale tests of premises with fire in a three-story building revealed that the error, determined when comparing experimental and calculated data, was not significant. A relative error did not exceed 28%, and root-mean-square deviation did not exceed 51 °C. This means that the modeling results are adequate, which allows to use this approach for predicting the behavior of building structures in a fire under realistic conditions.

Taras Shnal, Serhii Pozdieiev, Roman Yakovchuk, Olga Nekora

Cohesion of Slurry Surfacing Mix on Bitumens of Different Acid Numbers at Different Curing Temperatures

Cohesion of Slurry Surfacing mix is an important technological indicator that allows you to start traffic on time. In this article Slurry Surfacing mix curing is studied in three modes: 10 °C (high humidity), 20 °C (normal humidity) and 30 °C (high humidity). As binders for Slurry Surfacing mix there were used oxidized bitumens produced from light crude-oil and distillation bitumen produced from heavy crude-oil. There was confirmed that the first bitumens are characterized by low acid numbers, while the latter ones – by high ones. On the base of the bitumens there were produced cationic slow-setting bitumen emulsion and Slurry Surfacing mix. It was found that high-acid number bitumen is definitely optimum version in comparison with low acid number for the usage in Slurry Surfacing mix at different temperature modes – by criterion of cohesion strength build-up rate for the mix. This criterion consists of three periods (times) on mix curing: Set («Set» Torque), Traffic (Early Rolling Traffic) and Cure Time (Cured Slip Torque).

Iurii Sidun, Sergii Solodkyy, Oleksiy Vollis, Volodymyr Gunka

Influence of Climatic Factors on Runoff Formation and Surface Water Quality of the Stryi River Basin

Global changes in climatic characteristics affect the hydrochemistry of surface waters, apart from direct economic intervention. Such changes in the hydrological regime will affect the change in the qualitative characteristics of surface waters and the concentration and content of major components in river waters. Natural processes of formation of the chemical composition of river waters also violates anthropogenic influence. The purpose of the conducted research is to analyze the factors influencing the runoff formation and surface water quality of the foothills of the Ukrainian Carpathians and the choice of optimal flood protection of inhabited territories from destruction. The abnormally warm weather caused the lack of snow reserves as a major factor in spring runoff. There was no permanent snow cover until the end of the second decade of February except the Carpathian highlands. The persistent lack of rainfall in the autumn and winter has determined the low water content of most rivers in the country. Studies have shown that the overall water-management and ecological situation may be complicated, especially in water bodies with significant anthropogenic load, with a deterioration in water quality due to the limitation of the dilution of polluted waste water and the inability of natural washing of river beds to dry up.

Volodymyr Snitynskyi, Petro Khirivskyi, Ihor Hnativ, Roman Hnativ

The Methodology of Experimental Bending Moments Determination in Bridge Span Structures

The article presents results of the study of the experimental bending moments in the nonlinear area of section deformation determined by the proposed algorithm and showed practically accurate using for close to the real size constructions of the full scale T-beam length 13,5 m with rigid/frame reinforcement. This beam was separated from adjacent beams of the bridge deck superstructure by cutting of welded metal plates of T-beam shelves and diaphragms. Then a testing metal structure system of individual design and execution, which consisted of a truss length of 15,0 m and a height of 2,5 m was installed. By means of ties and traverses system the external testing load was transferred to the existing bridge supports. The technique and algorithm of experimental bending moments determining by the values of beams cross sections vertical displacements obtained in field tests of bridge deck structures, which allow to take into account the physical nonlinearity of RC elements deformation, as well as the presence of existing defects and initial deformed and strained state of spatial structure.

Yuriy Sobko

Research of Temperature Regime in the Module for Poultry Growing

The task of modern systems of heat supply in the poultry houses are the maintenance of the necessary temperature parameters in the habitats of the poultry. On the basis of researches of infrared heating systems in poultry house an engineering technique for calculating the temperature regime in module for growing poultry has been developed. The module was equipped with an infrared heater and an exhaust outlet and allows designing efficient infrared heating systems in agricultural premises to ensure standard temperature regime. In this case, the technique is only resolved when the conditions for providing the required temperature and air speed parameters are met. If the temperature of the module tin changes from 16 °C to 35 °C, and inflow air speed varies from 0.2 m/s to 0.3 m/s, the infrared heating system and the ventilation system completely provide the normalized air temperature in the irradiation area. Based on an algorithm using a developed technique a computer program was developed. This program allows, through the use of a simple method of substituting input factors, to determine the parameters of the temperature regime of the module for poultry breeding.

Nadiia Spodyniuk, Anna Lis

Development of Component Composition of Engineered Cementitious Composites

The use of engineering cementitious composites – a specially developed cement-based material reinforced with fibers – allows to enhance the bearing capacity, stability under static and dynamic influences, as well as durability of building structures. The effect of component composition of engineering cementitious composites on workability, flexural and compressive strength was investigated from micromechanics principles point of view. It is shown that the optimal cement to sand ratio, partial replacement cement by fly ash, incorporation of polycarboxylate superplasticizer, as well as reinforcement of the engineered composites structure with dispersed fibers contribute to their mechanical properties both at early and later hardening period. The modified engineered cementitious composites are characterized 28-days compressive strength 61 MPa, flexural strength – 14.5 MPa and crack resistance coefficient 0.24. Partial replacement of Portland cement by fly ash causes formation of needle and fibrous hydration products in unclinker part that reinforce the matrix on the micro- and nanolevel and the phenomena of “self-reinforcement” is realized.

Nazar Sydor, Uliana Marushchak, Serhii Braichenko, Bohdan Rusyn

Physico-Chemical Investigations of Water Suspensions Microfillers

At present, microfillers are widely used in heavy concretes. Mineral composition and dispersity of microfillers differ. There is no single method for assessing the effectiveness of microfillers. The views of different researchers on the need to use these materials are different. There are many contradictions that need clarification. In the technology of transport concretes, carboxylate based superplasticizers are used, as well as melamine formaldehyde and naphthalene formaldehyde compounds. Firms that produce such superplasticizers indicate in the annotations only the basis of the additive component, and not the whole of its composition. The use of superplasticizers in different cements differs greatly in the effect of the action. A traditional method for determining the effectiveness of microfillers and superplasticizers in concretes involves the preparation of samples and their subsequent testing at various times of hardening. It is advisable to use simpler physicochemical methods. These are methods for determining the pH and electromotive force (EMF) of aqueous suspensions of cements and microfillers. Instruments for measuring these indicators are simple, and the results can help predict the effectiveness of the use of additives in concrete. This article presents the results of studies of the pH and EMF of aqueous suspensions of cements and microfillers with and without superplasticizers. We used ground quartz and limestone microfillers, as well as carboxylate and naphthalene formaldehyde superplasticizers. Dependences of changes in these indicators over time are obtained. Based on the data obtained, it is possible to determine how the electrochemical properties of suspensions vary with time.

Serhij Tolmachov, Olena Belichenko

Crack Resistance of Concretes Reinforced with Polypropylene Fiber

The article presents the results of the study of the influence of dispersed reinforcement of cement concrete with polypropylene fiber with different variations of fiber consumption, fine and coarse aggregates, as well as coarse aggregates’ maximum size on the strength and crack resistance. The analysis of complete state diagrams of the studied concrete series shows a slight difference in the subcritical stage of concrete failure (until the beginning of the main crack movement) between reinforced and non-reinforced concrete. The main advantage of the introduced polypropylene fiber could be observed in the supercritical fracture stage - the fiber inhibits the fracture process of the sample after the moment of the main crack development (when the maximum destructive load was already applied). The fracture toughness increases with grain size of coarse aggregate increasing from 15 to 20 mm, with subsequent stabilization of its value. Increasing of the cement-sand mortar amount in concrete leads to increase in the fracture toughness, while the specific effective energy consumption for static fracture does not change significantly and reaches the maximum value at grain spacing coefficient of 1.4. As the amount of introduced fiber increases from 4 to 7 kg per 1 m3 of concrete, the fracture toughness increases and remains at the same level with the maximum fiber content of 10 kg.

Yurii Turba, Sergii Solodkyy

Assessment of the Economic Feasibility of Using Alternative Energy Sources in Ukraine

The article deals with an analysis of the popular types of alternative energy sources and prospects for their application in countries with temperate climates, particularly in Ukraine. The need to compare the potential of alternative energy in Ukraine with the cost of equipment required for the use of alternative energy sources is substantiated. According to the specifics of each region, the concept of choosing efficient energy sources is defined, in particular, attention should be paid to comparing the cost of materials, capital operating and costs for each type of energy, in particular, Sun energy, biogas, biomass, air potential and geothermal energy. In the form of tables and nomograms presented data regarding to technically achievable energy potential for different regions of Ukraine. Analyzing the obtained data, it can be stated that geothermal energy, air potential and solar energy deserve special attention.

Malgorzata Ulewicz, Vasyl Zhelykh, Yurii Furdas, Khrystyna Kozak

Estimation of the Ecological Flow of Mountain River in Ukrainian Carpathians for Small Hydropower Projects

In recent years the construction of small hydropower plants has increased in the mountainous part of the Carpathian region. The modern requirements for the ecological flow of rivers are significantly increased. There are no regulations for determining the minimum ecological flow for small mountain rivers in Ukraine. The magnitude of the minimum environmental flow significantly affects the assessment of the hydropower potential of the river. Ecological flow calculations are complicated by the lack of hydrological stations in the upper part of mountain rivers. The purpose of the work is development of a simplified engineering method for determining the minimum ecological flow under limited hydrological data for small mountain river of Ukraine. It was carried out the minimum ecological flow calculation for two sections of the Irshava River in the Tisza basin to estimate the proposed method. For comparison, it was used method of the minimum ecological acceptable flow, wetted perimeter method, BFM, IHA, Tennant. Based on the analysis of European and Ukrainian methods, the simplified engineering method for determining the minimum ecological flow is proposed: for the mountain river it is the mean annual flow of 90% probability.

Svitlana Velychko, Olena Dupliak

Influence of Orientation of Buildings Facades on the Level of Solar Energy Supply to Them

Energy-efficient building forms take into account the fundamentals given for passive houses and zero energy houses. One of them is to account for the amount of solar energy received on the facade surface. The paper describes the study of the influence of the orientation of buildings facades on the level of solar energy supply to them. The paper presents theoretical dependencies for determining the amount of solar energy input to the facade surface due to its orientation relative to the sides of the horizon. In addition to the appropriate orientation of houses for the use of solar energy, the paper considers the need to use this energy by equipment on walls or windows. It was calculated that the difference in solar energy received by the surface of the Southern, South-East and South-West is no more than 5%. The paper suggests approximation equations that allows to calculate the amount of solar energy received on the different orientation facade surface.

Vasyl Zhelykh, Pavlo Shapoval, Stepan Shapoval, Mariana Kasynets

Methodology for Calculating the Composition of Fine-Grained Concrete with High Resolution

The article presents the methodology of designing the composition of fine-grained concrete, taking into account the method of compaction, the parameters of the aggregate and the binder obtained on the basis of a complex of experimental studies. The results of studies of the effect of the type of concrete mixtures and their method of compaction on the strength of fine-grained concrete and the relationship of strength with water-cement ratio are presented. An original method of determining the thickness of a cement paste film on aggregate grains is proposed, which allows one to calculate the ratio between the components of a concrete mix based on the physical model of the concrete structure. The developed calculation methodology can be used both on computer systems and manually thanks to the built nomograms. This methodology is suitable for practical application in determining the composition of concretes for fine-walled and thin-walled products, as well as for thick-reinforced, reactive-powder concretes and fiber concrete.

Vadim Zhitkovsky, Leonid Dvorkin, Vitaliy Marchuk, Mykhailo Fursovych

Maximum Daily Stormwater Runoff Flow Rates at the Inlet of the Lviv WWTP Based on the Results of Systematic Hydrologic Observations of the Catchment

Method of the estimation of maximum daily stormwater flow rates from the urban catchments of cities with combined sewerage system is presented in the paper. Full-scale sample survey of the territory of the Baltic Sea catchment of the Lviv city allowed to obtain the total area of technical watershed of the Baltic Sea catchment – 40.79 km2. Based on the regression analysis of results of the survey, the power law dependency between the total and effective imperviousness of the catchment is obtained. Weibull model approximation, based on the actual data for the rainfall events in Lviv for the last 20 years, is obtained and can be recommended for the maximum daily rainfall depth estimation depending on the value of the return period. Estimated maximum flow rates of stormwater runoff at the inlet of Lviv WWTP as the function of the return period P in the range of 0.1 yr. to 5 yr. is presented.

Volodymyr Zhuk, Lesya Vovk, Ivan Matlai, Ihor Popadiuk

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