bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental study on regeneration performance of the heat localization method for absorption air-conditioning system
Authors: Zhang Wanshi , Wu Yunlei , Li Xiuwei
Published: January 2021

Due to serious energy shortage, it is urgent to reduce energy consumption from burning of fossil fuels. Driven by low-grade heat, absorption system is a promising energy conservative air-conditioning system for buildings. However, the main obstacle is the poor performance as a result of the energy waste in conventional thermal regeneration process. With the aim of performance improvement, a heat localization method is proposed for the regeneration process of absorption system. It can improve energy utilization efficiency through thermal energy localization on the evaporation surface. Preliminary experiments have been conducted to test the regeneration performance with this new method. Some parameters have been investigated with the experimental data. Moreover, by comparison between the heat localization method and traditional heating method, it indicates the energy utilization efficiency with the heat localization method are 1.8 to 2.8 times higher than that with the traditional heating method. The performance of the system has been greatly improved. The energy utilization efficiency of the regeneration process can reach 36.9% under certain working conditions. With the performance improvement, the popularization of absorption system will be promoted.
Quantification of Citarum watershed damage for flood control efficiency
Authors: Safarina Ariani Budi , Chairunnisa  , Farfian Roni , Hatmoko Waluyo , Sadidah Muthiah
Published: January 2021

Watersheds damage causes disturbance to the river system and floods. Watershed performance can be monitored regularly through parameters to avoid damage. The purpose of this study is to formulate a quantification of watershed damage based on the flood parameters. This research was conducted in the Citarum River Basin located in West Java Province, Indonesia. The method used is an analysis of the rainfall-runoff model on four Citarum tributaries, namely Citarik, Cisangkuy, Cilember, and Cimahi River. The unit hydrograph resulting from modeling is derived to load discharge using the convolution method. Effective rainfall is determined based on runoff coefficients derived from land-use maps. The discharge capacity of the river is determined by measuring the cross-section of the river near the branching location. Indicator of watershed damage is the ratio between load discharge (Qload) and river capacity discharge (Qcap). The watershed is categorized as damaged if Qload/Qcap > 1. The level of watershed damage is measured by the damage index ID = ?Q/Qcap. Damage categories are low, moderate, and severe. Based on the results of the study, Cimahi river area is not damaged. Citarik River and Cisangkuy River are categorized as low damaged and Cilember River is heavily damaged.
Analysis of the indoor fire risk based on the Pyrosim simulation
Authors: Zhang Hong , Yan Gaopan , Li Mingjun , Han Jinsheng
Published: January 2021

In order to study the effects of different fire conditions on the indoor fire process, this paper uses Pyrosim to perform a fire simulation of a simple indoor room in the paper, we have compared and analyzed the changes of the temperature, the smoke layer height, and the heat flow in two different conditions with the window and door being open, or with the window closed but the door opened 30 seconds later after the fire broke out. Pyrosim simulation results show that in the first 30 seconds of the fire outbreak, the fire development has nothing to do with the opening and closing of doors and windows. In the middle and late stages of the fire, when the door and window are fully open, the temperature and heat flow of the simulated room are low, and the height of the smoke layer from the ground is high. In the simulated room, with the window closed and the door opened after 30 seconds, the maximum temperature in the simulated room was about 10 higher than that in Condition 1.
Effect of Fly Ash Content on Properties of Fibre Reinforced Cementitious Composites
Authors: Yu Baoying , Zhou Jianwei , Kong Yaning , Gao Yuxin , Yang Wen , Cheng Baojun
Published: January 2021

The effects of 20%, 30% and 40% fly ash on the properties of fibre reinforced cementitious composites were studied. The results showed that the fresh slurry changed from shear thinning to shear thickening with the increase of fly ash content. The flexural strength of specimens increased slightly, but the compressive strength of specimens decreased with the increase of fly ash amount. Moreover, the flexural strength of all specimens showed different degrees of shrinkage over time. With the increase of the content of fly ash, the elastic modulus of specimens decreased.
Analysis of problems in building ventilation energy-saving design
Authors: Wang Shouchuan , Li Siwen , Zhou Yuwen , Ge Tan , Wang Xiaoguang
Published: January 2021

With the development of modern science and technology, the work of all walks of life has been further improved, and related content has become more abundant. Building construction is a problem that people attach great importance to now. Only by better grasping the relevant content, developing the core strength, and improving the strength of the enterprise can practical problems be effectively solved. Building ventilation and energy-saving design is one of the important aspects. The problems in the ventilation design are handled well, the analysis is carried out accurately, and effective solutions are grasped to ensure the quality of the design, so as to play an active role in the development.
Ground Settlement analysis of Metro Interval using PBA method in the Loess region
Authors: Wu Hao , He Baobing , Luan Guitao , Zhu Junhao
Published: January 2021

In the construction of urban subway, the control of surface settlement has become the key and difficult point in the construction. As a common method in subway tunnel construction, PBA method has been widely used in many areas in China. This method performs well in settlement control. In addition, the supporting system of piles, beams, and arches formed during the construction process of this method effectively avoids the impact of the open-cut method on urban traffic. Therefore, this paper will combine the engineering conditions and the existing research results to simulate the various construction stages of the subway interval excavation in the loess area by establishing a Midas model. Combined with the results of numerical simulation, four increasing stages of surface settlement and corresponding settlement ratios are obtained, and the characteristics of surface settlement troughs are analyzed. This research is helpful to further understand the increasing law of ground settlement during the construction of metro interval in loess area.
Curriculum system design for intelligent construction based on VR technology
Authors: Zou Jixue , Zhang Jin
Published: January 2021

With the emergence of AI, IOT, 5G technology, cloud computing and other terms, the digital era has significantly arrived, the national universities cultivate new engineering complex talents who adapt to the new era, which will bring great significance to promote technological innovation in the construction industry, and most institutions combine their own positioning to carry out professional reform in order to actively embrace industry changes. The purpose of this article is to explore the construction of intelligent construction professional curriculum system based on VR technology under the new situation, with the aim of innovating the layout mode of intelligent construction professional curriculum system, improving the training effect of new engineering intelligent construction talents, adapting to the development of information technology, and promoting the innovation of engineering construction technology.
Application of fractal theory in diagnostics of composite materials
Authors: Akhmetkhanov R S
Published: January 2021

The article presents the results of studies to identify the features of diagnostic acoustic signals when defects are detected in composite materials using the methods of the theory of fractals. The use of the analysis of the spectral power density (PSD) and wavelet spectra of these signals did not lead to the detection of significant quantitative differences in the acoustic signals during the process of sample diagnostics (panel 4 mm thick). Acoustic signals from the standpoint of analyzing the characteristics of multifractal spectra were analyzed. It is shown that the defect state of the sample corresponds to the monofractal characteristic of the multifractal spectrum.
Quality control of composites
Authors: Berezin A V , Maidanov I S , Smelov S A , Gadolina I V
Published: January 2021

According to the kanban (just in time) system, any production system needs continuous improvement. Possessing excellent mechanical properties, composite materials demonstrate a significant variation of properties (in particular, strength indicators). The composite manufacturing process is multi-stage and requires optimization after thoughtful consideration of the nuances. Exploratory data analysis was applied as a first step for this analysis. It serves as a basis for further experimental research, which it is desirable to carry out using the mathematical theory of experimental design. After the first stage of the study of the process, namely, the study of the statistical reproducibility of the technological process, in order to obtain more complete information about the process, it will be necessary to introduce additional influences on it.
Threshold level of cast railway steel loading in the process of operation
Authors: Lebedinsky S G , Moskvitin G V , Pugachev M S
Published: January 2021

The authors studied the pattern of fatigue cracks distribution in railway J02002-type grade steel at threshold level of operational loading. The study was based on simulation of operational load combining the conditions of straight and curved part of the road. The load level reduction was based on the pattern of the change of the tested sample hardness with the development of the crack. The authors found the relation between the load level reduction, the crack growth rate and the number of load units. They determined the coefficient of similarity of operation loading form, at which there is no fatigue crack growth in the steel under consideration.
Development of models for risk analysis and optimization of risk reduction costs
Authors: Panov A N , Reznirov D O , Yudina O N
Published: January 2021

The article deals with the actual problem of risk analysis and management in the technosphere. Proposed and developed: classification of risks (events, variations, bifurcations); risk analysis structures; risk management structure of variations and bifurcations; models for optimizing the cost of risk management.
Technological biomechanics of fibrous composites
Authors: Polilov A N , Tatus N A
Published: January 2021

There are numerous examples of using Natural solutions in technology, especially, in design of composite structures [1]. Bio-inspired methods (suggested by Nature) are widely used in human activity. For instance: how does branch-trunk connection work? You can break a branch, but nearly impossible to tear the branch off the trunk. The connection turns out to be stronger than the part itself. So far, designers of composite products can only dream of such methods of joining.
Ceramic coatings synthesis on valve metals and alloys by micro-arc oxidation
Authors: Rakov D
Published: January 2021

The most pressing tasks in engineering and materials science are the synthesis of high-quality coatings with high durability and corrosion resistance. This paper presents ceramic coatings synthesis on valve metals and alloys by micro-arc oxidation. The synthesys based on advanced morphological approach. The approach is to generate a sequence of algorithms, comparison and selection of the set of rational variants of technological solutions. The approach allow to reduce the dimensions of the morphological set and improve the efficiency of search procedures.
Damage accumulation in cyclically stable steel under low-cycle loading and elevated temperature
Authors: Romanov A N
Published: January 2021

Based on the strain-kinetic fatigue fracture criterion, the kinetics of accumulated damages in structural carbon steel under low-cycle loading at an elevated temperature (150°C), at which the material begins to develop stress aging processes, is estimated. It is shown that stress aging, strengthening the material, narrows the durability area in which there is quasistatic destruction, the limiting case of which is the buckling failure of plastic strain, like single static destruction. This increases the fatigue fracture range, the limiting case of which is the formation of the primary fracture. The recoverable plastic strain causes the main damaging effect. Stress aging contributes to an increase in damage from elastic strain, although in the area of low-cycle failure, the share of damage from elastic strain remains small, growing with increased durability, and in the area of multi-cycle fatigue, this share becomes prevalent. Hardening from stress aging inhibits the development of damage from the one-way accumulated strain. The author confirms the validity of applying the strain-kinetic criterion of fatigue fracture to describe the damage kinetics and limit states during the cyclic elastic-plastic strain of carbon steel in the presence of weak stress aging.
Nonlinearity of the stress-strain dependence of quasi-isotropic CFRP laminate under re-static loading
Authors: Severov P B
Published: January 2021

As part of the task of studying the degradation of material properties under re-static loading of a quasi-isotropic CFRP laminate the nonlinearity of the stress-strain dependence in the areas of active deformation is proved. The optimal curve approximating the experimental data from the point of view of the problem is chosen. The change in the derivatives of this curve can be use σ to assess the degradation of the material properties during re-loading.
Active polymeric reducing agent for self-healing asphalt concrete
Authors: Inozemtcev Sergey , Korolev Evgeniy
Published: January 2021

The possibility of using an active polymer component as a reducing agent for the implementation of the self-healing of asphalt concrete technology is considered in the paper. It was found that the thiol-containing urethane AR-polymer is an effective reducing agent capable of replacing traditional reducing agents based on hydrocarbon oils. AR-polymer is a reducing agent that can be encapsulated using alginate technology. The volume of the reducing agent in the capsule is limited to a maximum allowable value of 83±1%, which can be achieved using the alginate technology. It has been proven that the type and properties of the reducing agent does not affect the change in the mechanical properties of the capsules. The strength of the capsules decreases by 2…6% for different ratios of RA/A when the content of sodium alginate decreases from 3.33% to 2.08%. The greatest efficiency of capsules with the maximum content of AR-polymer as a reducing agent and higher strength is achieved when using emulsions containing 2.50% sodium alginate at RA/A = 5.0 ± 0.2.
Biomodified building materials on the base of mineral binders
Authors: Bruyako Mikhail , Grigor’eva Aleksandra , Stepina Irina , Golotenko Darya , Podsevalova Anastasia
Published: January 2021

In order to increase the service life of structures, there should be taken various measures aimed at damaged elements restoration followed by their due maintenance. Enhancing material’s properties by the ability of self-healing is done with the help of the additive and is seen as the effective method of preservation of the materials’ properties. The analysis of the previous studies has shown that biological and biochemical processes are given preference to facilitate self-healing process. The purpose of the present study was a development of the method allowing for the increase in durability of buildings structures by activating and providing self-healing processes of building materials. The application of the developed bioadditive allows retaining reliability of construction products at the very initial stages of microflaws’ appearance by filling them up with the essential products of bacteria with urease activity. The bacteria are introduced into the body of the material at the manufacturing stage. This method of imparting a self-healing effect to the materials has many points in its favor such as sustainability, cost effective performance, and reduced labor costs for repair and restoration work. The method could be used in the structures of any complexity and for reconditioning of heritage sites. The selected microorganisms act upon the mix as surfactants, that is, they lower the water-cement ratio of sand-cement mortars by augmenting the concentration of bio-surfactants. This feature of cells enhances the efficiency of the developed additive. Application of these microorganisms as a component of a biologically active additive can significantly increase production performance and the efficiency of building structures’ operation due to higher efficiency of microorganisms responsible for initiating self-healing processes in building materials. According to the research results, zeolite could be regarded as the most suitable porous material acting as a carrier of cell immobilization.
Aerated concrete with predetermined pore parameters for the exterior walls of energy efficient buildings
Authors: Adilkhodjaev Anvar , Hasanov Bahriddin , Shaumarov Said , Kondrashchenko Valery
Published: January 2021

This article presents the results of theoretical and experimental studies on the development of aerated concrete with predetermined pore structure parameters. Investigations of the physical-mechanical and heat-engineering properties of external wall fences made of cellular concrete are given and the optimal parameters of the porosity of the material structure are established. The testing results were tested in the factory and the main properties of aerated concrete with an improved pore structure were determined.
Verification of the building materials production process mathematical model
Authors: Vasil’eva Olga
Published: January 2021

We consider a new mathematical model of the process of production of building materials based on the reaction of autocatalysis in the case of two reagents. The considered mathematical model takes into account the terms of a higher order of smallness for a small parameter. The results obtained when considering a reaction in an infinite cylinder with a random distribution of chemical reagents at the initial moment of time using two different mathematical models are compare.
Hardening of cutting tools by combined gas nitriding method
Authors: Eshkabilov Kh , Berdiyev Sh , Kamolov B
Published: January 2021

In order to improve the strength properties of cutting tools made of high-speed steels, the article presents the results of a study of the possibility of using a combined method of surface hardening, which consists in nitriding in an ammonia medium at the first stage and oxidizing the nitrided layer in water vapor at the second stage.

The formation of a thin dense oxide film consisting of a single magnetite and a dense nitride layer under it as well as a zone of internal nitriding following it are studied on the surface to be strengthened.

It is established that the combination of the process in the first stage by zaevtektoidnoj temperature for the system “Fe-N” the temperature intervals of martensite transformation of residual austenite and the second step by zaevtektoidnoj temperature for the system “Fe-O” according to temperature intervals and tempering after hardening allows you to get the diffusion nitride-oxide layer with the desired structures and properties on the surface of high-speed steel.
Physicochemical fundamentals of modifying concrete mix and concrete
Authors: Khasanov Bakhridin , Vatin Nikolai , Mirzaev Timur , Suyunov Abdugani , Radjabov Mirzokhid
Published: January 2021

It is possible to obtain highly efficient construction conglomerates by modifying the structure of cement stone and concrete. Consequently, modification of the concrete structure in this direction is intended to improve the technological properties of the material. By modifying, it is possible to change the kinetics of the growth of physical properties and the final values of the strength of concrete.

Without considering the physical and analytical mechanism for modifying the structure formation of concrete, we note that it is primarily aimed at reducing the amount of water -a mixture in a unit volume of material. However, various studies have proved that in the initial period, the structure formation of the cement stone develops in the optimal direction only at a certain volumetric water content. The limiting reduction in water content makes it difficult to hydrate the binder, limiting the final strength properties of the material. At the same time, the final strength properties of the material are improved with an all-round decrease in the volumetric water content of the mixture. In all cases, the modification of concrete assumes its composition is unchanged from the mixing of the mixture to the final stage of the formation of the concrete structure.

At present, only isolated attempts are known to physically modify concrete, for example, during its evacuation. In this case, the optimal amount of mixing water is introduced into the concrete mixture, which ensures the optimal flow of the binder hydration reaction. The subsequent suction of water, changing the initial composition of concrete, leads to a deep modification of its structure formation. In particular, the density of the material and its strength properties sharply increase. It should be noted that physical modification of concrete leads to a change in the nature of fixation of binder particles.
Optimization of the composition and technological processes of dispersed cement systems with high performance properties
Authors: Tkach Evgeniya , Semenov Vyacheslav , Shumilina Yulia
Published: January 2021

The technological parameters of obtaining cement disperse systems are considered. It is shown that the optimization of technological processes allows the development of dis-persed cement systems with high protective resistance during the operation of buildings and structures. It was determined that optimization of the parameters makes it possible to select the most effective ratio of cement and finely ground filler from concrete scrap, the optimal amount of modifier additives, and then the ratio of colloidal cement glue and sand (aggregate) in order to obtain mortar compositions for decorative coatings with high strength properties. It was found that grinding sand or crushed concrete scrap allows not only to increase their specific surface and obtain the required particle size distribution, but also to improve the surface quality of particles by removing and destroying surface inactive films, which increases the reactivity of the filler in various processes. Mechanical activation in combination with modifying additives allows to give the necessary properties to colloidal cement composites using optimal techno-logical parameters of processing. The influence of the particle size distribution of sand on the strength characteristics of decorative coatings based on colloidal cement glue is determined de-pends on the ratio of colloidal cement binder to sand. Studies have shown that the fractional characteristics of sand are optimal, in which dense packing of grains and approximately equal fractions of fractions are ensured. It has been established that dispersed cement systems with an optimal fractional composition of the filler have a water-holding capacity that significantly ex-ceeds the standard values.
Identification of a potential danger zone for industrial enterprises in the Far North
Authors: Lukyanova Yuliya , Lavrusevich Andrey
Published: January 2021

The accident on may 29, 2020 in Norilsk showed that the problem of permafrost melting is currently relevant for all industrial enterprises in the Arctic region. Soil thawing leads to deformation of objects located on territories with similar engineering and geological conditions. You can often see houses and roads riddled with small and large cracks, buildings with deformed foundations. All these are the results of the processes that control the life of permafrost. It is necessary to study and observe the processes of degradation of permafrost so that this phenomenon does not come as a surprise, in order to have time to take measures to prevent an accident. It is shown that the boundaries established by regulatory documents do not prevent the release of pollutants into the environment in the event of an accident at the facility. As a result, it is useless to establish a sanitary protection zone. Continuous monitoring of the state of permafrost in the area where industrial facilities are located can be a preventive measure.
The prospects of information technology using for the analysis of industrial buildings defects
Authors: Shilov Leonid , Evtushenko Sergey , Arkhipov Dmitrij , Shilova Liubov
Published: January 2021

The article discusses an approach to describing cracks using machine learning algorithms to simplify the issuance of defective statements for the reconstruction object. The presented approach makes it possible to describe the geometric characteristics of concrete structures and their defects by sets of equations in order to subsequently find the main characteristics of defects and enter them into the defect lists.
Construction Specifics of Oil Tanks with a Capacity of 20,000m3 on Large Strata of Collapsible Loess Soils
Authors: Abelev Mark , Chunyuk Dmitry , Kopteva Olga
Published: January 2021

The article presents experience in compaction of a large stratum of collapsible loess soils (type II collapsibility) during the construction of 4 metal tanks with a capacity of 20,000 m3.
On deformation criteria of a special limit state of eccentrically compressed elements of RC building frames
Authors: Savin Sergey , Manaenkov Ivan
Published: January 2021

At accidental impacts caused by the sudden removal of a load-bearing element of the building frame, the stress-strain state of the sections of eccentrically compressed structural elements such as columns, pylons, braces and belts of trusses, etc. becomes more disadvantageous than their stress-strain state at the stage of normal operation. The factors that lead to such a situation are sharp increase in the eccentricities of loads attaching, slenderness of cross sections, corrosion, initial curvature and mechanical damages. In these cases, buckling scenario for the exhaustion of their bearing capacity is a possible scenario. The paper proposes an approach to the obtaining of deformation criteria for assessing the special limiting state of eccentrically compressed bar elements of reinforced concrete frames. Such an approach is based on the use of a combination of nonlinear deformation analysis and nonlinear stability analysis. Paper shows that the limiting values of deformations for the considered reinforced concrete element can be determined by the criteria of strength or buckling, depending on the ratio of the forces acting in the sections of the structural element.
Strength of heavy concrete during static-dynamic deformation
Authors: Fedorova Nataliya , Medyankin Michael , Fedorov Sergey
Published: January 2021

Method and results of determination of strength and deformation characteristics of heavy concrete at static loading to the specified stress level, followed by high-speed loading with dynamic load, are presented. The process of testing a series of concrete samples of one strength class is described to obtain the performance characteristics of concrete at static, dynamic and static-dynamic loading. Comparative analysis of the obtained experimental data was carried out under different loading modes of prototypes. It was established that during dynamic and static-dynamic loading there is an increase in the level of relative stresses corresponding to the beginning of concrete dilatation by 20-30% relative to the results of static tests. The obtained experimental results are of interest for solving problems related to the problem of survivability of buildings and structures and their protection against progressive collapse, in particular in determining criteria of strength and deformability of concrete at a special limit state.
Final smoke spread simulations for Tunnel traffic & operation simulator
Authors: Danišovič Peter , Šrámek Juraj
Published: January 2021

Road and highwaz tunnels have become an essential part and an important element of the road network. In terms of general transportation and transit of goods they have also transnational significance. Tunnels located on the trans-European road network with a length of more than 500 m must also comply with the requirements of European Directive 2004/54/EC. That directive imposes an obligation on investors and management organizations to pay particular attention to the fire safety of tunnels. This paper describes final smoke spread simulations of road tunnel fires which were created as outputs of the project entitled “Models of formation and spread of fire to increase safety of road tunnels”.
Computation of the influence of the surcharge on the state of stress of the round plate on a bumping foundation
Authors: Atarov Nikolay
Published: January 2021

The problem of calculating a round plate located on the surface of a combined foundation is being considered in the paper. An analytical solution is deduced for a plate of finite stiffness and a stiff plate (round stamp) under the influence of an axisymmetric bending. The influence of an axially symmetric ring load applied to the surface of the base outside the slab is analyzed.
Automated assessment of information models for compliance with “green” standards
Authors: Makisha Elena , Rybakova Angelina
Published: January 2021

In modern construction, environmental issues are becoming increasingly important, therefore the concept of “green” construction gains growing popularity among both customers and developers. At the same time, information modeling technologies is witnessed to become widespread worldwide. This article reveals the design and construction of modern buildings in accordance with standards of “green” certification based on building information modeling methods. The advantages of building information models, such as rational design decisions, object analysis by various parameters, and quick access to quantitative and qualitative information provides easier certification of “green” buildings, and as a result, the efficient operation of the future object. The purpose of this research is to study the possibility of automated assessment of building information models for compliance with rating systems of “green” construction that can be achieved by analysis «green» construction aspects in the combination with information modeling, approaches to models evaluation within the framework of «green» certification standards and analysis of automated models verification methods. The practical result of the research will be an algorithm for automated evaluation of information models for compliance with” green” standards. Based on the theoretical part of the study, directions for further research in the field of sustainable construction based on BIM will be formulated.
Identification of the architecture in XXI century “Generation of Legacy Reborn from Innovations”
Authors: Aukhadiyeva Laura
Published: January 2021

Scientific discoveries based on innovative materials and technologies of the late XX and early XI centuries are the main sources of innovation in architecture. They made it possible for the architects to widen horizons of creativity and imagine the vision of a future world that was unattainable only a while ago. By studying the technique of “combination” of tradition and innovation in the creative works of Sir N. Forster (Great Britain), an architect with a world renown, and pioneering work of an architect A. Khan (Great Britain) and many others allow to look at the problem of regional identity of architecture under a reassuring vantage point where a blind spot – problems of keeping the identical architecture and its developmental trends – is uncovered in inseparable connection with the globalization processes.

Brief summary. Globalization and regionalization – two phases of world development having an impact on the development of world architecture where the method of “generation” of legacy does not constitute a template since the method of analysis and synthesis of science and art allows for the possibility of the widest range of innovation.
Integration of abandoned manor parks, that are cultural heritage sites, into an environment, that corresponds to the “smart city” concept
Authors: Pozhilova Anastasia , Leptuhova Olga
Published: January 2021

The paper is devoted to the possibility of urban development using manor parks, which are cultural heritage sites, to improve the quality of the built environment. To justify the type of their use, we propose a methodology based on the factors identified during the study that affect the type of use of manor parks, as well as on the analysis of existing similar, already optimally used manor parks and a sociological study of the needs of potential visitors. Using this method will help improve the quality of the built environment when implementing the “smart city” concept.
Reinforcement of reinforced concrete structures with composite materials
Authors: Khayrnasov Kamil
Published: January 2021

Composite materials are becoming more widespread in many areas of the national economy, including in construction, due to their high strength parameters with low weight characteristics. Currently, composite material is the most promising material in building. The use of composite materials in construction for the manufacture, reinforcement and repair of reinforced concrete structures facilitates their lightening, allows varying the physical and mechanical characteristics by positioning the composite base in the desired direction. Therefore, consideration of the issues of reinforcing floor slabs commonly used in construction with composite materials is an important and relevant topic. The use of composite materials in reinforced concrete elements provides increased crack resistance and stiffness of reinforced concrete elements. This is due to the localization and redistribution of deformations in the stretched zone.
Experimental and theoretical study of post-tensioned unbonded beams
Authors: Gavrilenko Alexey , Barkaya Temur
Published: January 2021

Paper contains data obtained during a bending test of four post-tensioned unbonded beams as well as description of geometry of test specimens and strength properties of used materials. Midspan deflection, tendon stress increase, cracking moment and ultimate bending moment were measured during the test. Crack propagation pattern was assessed as well. Ultimate bending moment, cracking moment and midspan deflection were then estimated using reinforced concrete analysis methods widespread in Russia. Comparison of the test data and calculation results shows that nowadays there are not domestic analysis methods well enough to fully estimate the unbonded post-tensioned beams.
Comparison of the impacts of harmonic and seismic waves on an underground pipeline during the Gazli earthquake
Authors: Kosimov Elbek , Mirzaev Ibrakhim , Bekmirzaev Diyorbek
Published: January 2021

The paper considers a class of problems of the dynamics of spatial systems of underground pipelines under the action of three-component seismic waves propagating in soil based on instrumental records of real earthquakes. A comparison was made of the impacts of harmonic and seismic waves on an underground pipeline during the Gazli earthquake. A graphical method for determining the dominant period to be used in calculations for harmonic impact was given.
Nonlinear analysis of constructions from different materials based on unified plastic constitutive relations
Authors: Panasyuk Mark , Petrakov Aleksandr , Petrakova Natalia
Published: January 2021

In the paper the plastic constitutive relations based on the hypotheses of the plastic flow theory, unified for different materials, such as soil ground, concrete, metal etc. are proposed. These plastic constitutive relations are based on the hypotheses of the Mises-Schleicher-Botkin theory of failure. The strength characteristics of materials, determined by standard methods, are redefined for octahedral sites, they are invariants for. The problem is solved by the finite element method (FEM). The calculation model MFOE made up of singular finite elements (tetrahedral, triangular plates, rods). This fact increases the accuracy of the description of loading paths in finite elements and ensures a unique correspondence of the constitutive equations to elementary volumes of the construction. The use of singular finite elements is associated with a large amount of access memory for storing the stiffness matrix of the system. So, the range of practically solvable problems limits significantly. To eliminate this contradiction, the Newton’s iteration method – SOR method is developed for equilibrium equations solving in the design of finite elements structures. An iterative algorithm is obtained. It does not require assembly of the system stiffness matrix for its implementation. The volume of operational information is proportional to the number of finite elements in the system. Due to the traditional approach, which requires the assembly of the system stiffness matrix, the amount of operational information is proportional to the square of the degree of kinematic indeterminacy of the system. While using the iterative algorithm, the size of the stiffness matrix and the time of solving are reduced. The results of a nonlinear analysis of soil massifs and concrete structures are represented.
Numerical analysis of the ultimate compressibility of concrete with indirect reinforcement for plotting a stress-strain diagram
Authors: Manaenkov Ivan , Savin Sergey
Published: January 2021

Indirect reinforcement is one of the effective ways to increase the strength and deformation characteristics, which is achieved by creating a volumetric stress state in concrete. For the design of reinforced concrete structures with indirect reinforcement, the calculation method based on a nonlinear deformation model is well suited. For such calculations, it is required to construct the stress-strain diagram, which will most accurately describe the relationship σ-ε. The article presents a numerical analysis of increasing the bearing capacity and deformations of concrete of various classes with indirect reinforcement in the form of welded meshes. Selected formulas to determine strength and ultimate compressibility. The problems arising in determining the compressibility limit of concrete with indirect reinforcement for engineering calculations are noted. Recommendations for calculating the parametric points of the stress-strain diagram are given.
Method for calculating the porosity of cement composite materials using X-ray computed tomography
Authors: Sharanova Anastasia , Dmitrieva Maria , Leitsin Vladimir , Shinyaeva Maria
Published: January 2021

X-ray computed tomography is a promising method for non-destructive testing of the internal structure of materials. The article provides an overview of the use of computed tomography to study the structure of cement-based composite building materials. Computed tomography of four samples of fine-grained concrete mixture was performed: basic composition and compositions with different contents of additives of redispersible polymer powder and calcium formate. A method for calculating the porosity in these samples using a constructed 3D model and special software is presented.
Equivalent viscous damping ratio for a RC column under seismic load after a fire
Authors: Tamrazyan Ashot , Chernik Vladimir
Published: January 2021

The problem of taking into account combinations of special influences in the design of buildings and structures is currently quite relevant. In the event of a combination of fire and seismic load, two options are possible: fire after an earthquake and an earthquake after a fire. This work is devoted to the development of the methodology for calculating RC columns when the second option appears. It is known that fire effects reduce the mechanical characteristics of concrete and reinforcement. When calculating for seismic loads, it is also important to understand how the properties of a structure change during heating to dissipate deformation energy under low-cycle loads. When calculating RC columns using the displacement based design (DBD) method, dissipative properties are estimated the viscous damping ratio. In this work, this ratio is determined by considering the energy losses in one cycle of oscillations, which are equal to the area of the hysteresis loop. Hysteresis loops are determined by numerical calculation of RC columns for a combination of vertical preload and quasistatic horizontal displacement. The mechanical properties of the columns correspond to different fire times: 0, 30, 60, 90 and 120 minutes. In numerical modeling, it was found that the total energy that the column is capable of dissipating decreases with increasing duration of fire exposure. In its turn the hysteresis damping ratio at different fire duration can be either more or less than its initial value. The hysteresis damping coefficient decreases only for a time of fire of 30 and 60 min. With a longer fire duration (90 and 120 min), the coefficient does not decrease.
Influence of lowering groundwater level on the behavior of pile in soft soil
Authors: Znamenski Vladimir , Hegazy Osama , Sayed Diaaeldin , Thuy Duong Le
Published: January 2021

The article presents the results of numerical analysis of the development of negative skin friction forces of a single pile by lowering the level of the groundwater ta-ble in soft clay soils. The analysis is conducted with a three-dimensional model (3D) us-ing the ABAQUS software package. Results from the present work are found to be in congruent with the available published results. Moreover, the influence of lowering of the groundwater table in distribution of negative skin friction and axial forces on the pile as well as the maximum relative displacement between the soil and pile at various stages has been observed. The compression of the pile material is also taken into con-sideration in the study. Based on the results of the current numerical analysis, an equa-tion has been proposed for estimating the additional load on the pile, which is caused by negative frictional forces.
Use of natural the fracture of coal under the regulatory impact of water hammer in the coal-watercoal cluster of utilities sector
Authors: Chernyshev Sergey , Zommer Tatyana
Published: January 2021

The project to establish a prototype coal-coalwater cluster housing involves the use of constructed or existing boilers innovative coal-water-carbon technologies, including recycling and solid types of coal fuel in coal-water fuel slurry followed by burning in specially equipped furnaces. Analysis of the processes of brittle destruction of coal as a fractured rock at the macro and microlevels has shown that directed hydromining with the release of methane contained in coal seams, as well as wet grinding with the production of a certain granulometric composition of watercoal fuel suspension by hydroimpact occurs through macro-and microcracks. Also, as a result of the research, it becomes possible to use natural fracturing of control coal in the framework of creating a pilot site for an innovative coal-watercoal cluster of housing and communal services. A control model for an innovative coal-watercoal technology based on automatic control of the granulometric composition using of natural the fracture of coal the regulatory impact of water hammer is proposed. The technological regularities of reducing the negative technogenic impact on geospheres are revealed, including the method of managing the environmental and technological qualities of innovative coal-water suspension based on automatic control of the granulometric composition when grinding coal using the water hammer method.
Mathematical modeling of failure of port control systems
Authors: Khripko Tatyana
Published: January 2021

The need to increase the capacity of ports is due to the development of the Northern Sea Route as a national transport route of Russia in the Arctic, the National Program for the Development of the Far East, in the context of an increase in trade with other regions of Russia, as well as the reorientation of cargo flows from the Baltic ports to Russian ones in Primorsk, Ust-Luga and Vysotske. Increasing cargo turnover and ensuring the strategic economic interests of Russia requires the reconstruction of existing and construction of new modern port-industrial complexes, provided with advanced technologies, including the automation of logistics management processes, production and engineering systems. This article describes a method for mathematical modeling of the failure of control systems for automation of cargo terminals of ports. Since failures in the operation of automation systems lead to an increase in the load of cargo berths (terminals) of both sea and river port complexes, to a violation of logistics schemes, and as a consequence to an increase in costs. Modeling is carried out using methods of probability theory, in particular, the Poisson distribution law. A comparison of the empirical and theoretical failure rates of automation is performed using the Pearson criterion. The performed modeling will allow determining the technical and economic indicators of new construction, reconstruction or overhaul, in terms of the engineering systems of the facility, and optimize the automation processes.
Environmental monitoring in construction for hydro-technical structures and land reclamation facilities of Uzbekistan
Authors: Nasrulin Aydar , Ergasheva Dilbar , Khamdamov Bekmamat , Shadibekova Fatima
Published: January 2021

The article is devoted to the urgent topic of creating a comprehensive geographic information system for environmental monitoring and decision support for hydro-technical structures and land reclamation facilities of Uzbekistan. The research results allow a more substantial assessment of the environmental situation, the fundamental features of the arid zone. For monitoring, a methodology is disclosed, which will help water and water organizations to plan and predict the environmental status in the water sector. The results of a comprehensive analysis of the Aral Sea basin using geographic information systems will help in creating a decision support system. The excessive use of water resources within the Aral Sea basin for agricultural, industrial, and wastewater needs has resulted in the contamination of water resources by a diversity of hazardous chemicals from anthropogenic. Expert questionnaires for environmental measures developed during the reconstruction of hydro-technical structures and land reclamation facilities. They are using the methodology of environmental monitoring. It is possible to evaluate and improve the hydro ecological situation of hydro-technical structures and land reclamation facilities in Uzbekistan