bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Geographical Information System in Environmental and Economic assessment of Run-of-river Hydropower in Central Vietnam
Authors: Lan Huong Nguyen , Thi Viet Nga Tran
Published: July 2020

Conventional hydropower exploitation includes building large dams and reservoirs would pose significant impact to the environment. Recently there is trend to switch from building large hydropower plant to small and medium size, particular run-of-river hydropower plant. This study assesses the feasibility of installing run-of-hydropower scheme in the Vu Gia Thu Bon river basin with regards to the environmental and economic impact. The analysis was performed using GIS to identify the location of power plant that might have environmental constrains. The economic payback of each power plant was calculated and spotted on the digital maps. The methodology proposed in this study could be helpful for decision-makers in the preliminary identification of the most suitable locations to install run-of-river plants in the Vu Gia Thu Bon river basin.
Initial stress state at installation of a single-layer lattice dome due to errors of its assembly
Authors: Lebed Evgeny
Published: July 2020

The paper presents the results of the numerical modeling of the assembly process of single-layer lattice domes with respect to random deviations in lengths of individual bars which was performed with a special purpose software SBORKA developed by the author. Modeling of the installation process of the dome frame was performed by sequential calculation of the coordinates of its nodes through simulation of the connection of individual bars in these nodes. The inaccuracies of the bar lengths used were random variables with a normal distribution law. Due to errors in the length of the bars, the actual geometric scheme of the dome frame is distorted in relation to the design scheme. To obtain objective data on such distortions, numerical computer modeling was performed repeatedly with statistical processing of the results obtained. The sequence of assembly of the dome frame was chosen such that the largest number of different types of rods were used. Distortions in the geometric scheme of a single-layer lattice dome do not allow its frame to be installed simultaneously on all support nodes. First, the dome frame is installed only on three support nodes, and then due to deformation under its own weight, the remaining support nodes are included in the work. This deformation of the dome frame leads to the appearance of initial stress state in the bars. In this research, computer static analysis of a single-layer lattice dome was performed for the action of the self-weight load of its frame. The analysis was made taking into account the sufficiency of the load to exhaust the existing gaps in the support nodes. Based on the results of these calculations, the initial stress state in the bars of the dome frame are obtained, which should be taken into account in the analysis and design of the structure.
Dynamic stress state of underground pipelines at junctions
Authors: Ismoilova Sabida , Loginov Pavel , Khamidov Saidjon , Akbarov Nodirbek , Kumakov Jakhongir X
Published: July 2020

A one-dimensional statement of unsteady wave problem of a longitudinal monochromatic wave propagation and reflection from a rigid stationary barrier to which an underground pipeline abuts is given. The linear viscoelastic Eyring model, which describes limited creep and limited relaxation, is taken as the pipeline strain law. Eyring model allows us to describe the behavior of underground steel and polymer pipelines under dynamic loading. The problem is solved numerically using the theory of characteristics, followed by the finite difference method in an implicit scheme. Numerical solutions obtained in the form of dependences of plane wave parameters: longitudinal stress, velocity and strain for fixed sections of the pipeline are analyzed in the paper. An analysis of changes in these wave parameters shows that at high frequencies of dynamic load generating the wave, the stress amplitude in the pipeline increases by two or more times compared to the load amplitude. This is due to the superposition of incident and reflected waves in the pipeline and to a high loading rate of the pipeline. At low frequencies of dynamic loading, such an increase is not observed due to the low loading rate. The obtained numerical solutions allow choosing the statement of problems on dynamic stress state of an underground pipeline depending on the frequency of incident wave. It is shown that the greatest longitudinal stress in an underground pipeline arises in points (sections) close to its connection with a rigid stationary solid body.
Shear waves around an underground pipeline
Authors: Sultanov Karim , Khusanov Bakhtiyar , Rikhsieva Barno
Published: July 2020

A two-dimensional axisymmetric problem of shear wave propagation around an underground pipeline under longitudinal motion of the pipeline is solved numerically. Due to the significant difference in pipeline and soil rigidity, the underground pipeline is considered to be a rigid undeformable body and the soil medium around the pipeline is modeled by a viscoelastic law in the form of a generalized Eyring model. To solve the problem, the finite difference method modified by the Wilkins difference scheme was used. On the contact surface of the underground pipeline with soil, the conditions of complete cohesion are fulfilled. Changes over time in shear stress, velocity and soil particles motion in the direction of pipeline axis in fixed sections of soil are obtained. The process of soil displacement around the pipeline at fixed time points is shown. The attenuation of the maximum values of wave parameters in soil in the radial direction with distance from the underground pipeline was detected. The maximum value of shear stress was reduced by three times compared with the value of shear stress at the contact with the pipeline. The effect of the load action time and unloading waves on the wave parameters in soil around the underground pipeline is also obtained. Based on the results of problem solution, the viscoelastic diagram “shear stress - shear strain” is obtained. The results obtained make it possible to determine the mechanism of formation of the stress state and soil reaction to the underground pipeline, which can be used in strength and reliability calculation of the pipelines.
Strategy for the evolutionary optimization of reinforced concrete frames based on parallel populations evolving
Authors: Tamrazyan Ashot , Alekseytsev Anatoliy
Published: July 2020

An algorithm has been developed for optimization of reinforced concrete frames with the possibility of forming a structure with a subsequent selection of reasonable section sizes and reinforcement for it. A modified genetic algorithm is used as the main search tool. The overall optimization process is divided into two stages. At the first stage, the topology is synthesized by randomly excluding groups of structural members as well as changing the position in space of the remaining groups. At the second stage, local parallel evolving genetic algorithms are performed for the formed topologies. With a common set of variable parameters, the migration of individuals between parallel populations is not allowed. An example of optimization of the multi-story building frame is considered.
The change in mass of insulating materials in the Vietnamese climate conditions
Authors: Nam Nguyen Tien , Grabovy Petr , Kazarnovsky Valery
Published: July 2020

In article obtained in laboratory experiments, water absorption characteristics and evaporation of water from the insulation materials to determine their weight change in tropical climates with the following characteristics: high temperature and humidity, a large number of medium and monthly rainfall seasonal rains lasting 6 months. Thus, the obtained results may be used to repair wall enclosing parts in the Vietnam construction industry. The characteristics of waterproof, moisture resistance, water evaporation, biological stability in insulation materials, which are used in the thermal protection of buildings in Russia and in the world. Evaluation experiments were performed on the characteristics of water absorption and water evaporation of heat-insulating materials (mineral wool, polyfoam, extruded polystyrene) in the laboratory in three situations: the location of samples on the surface of the water, drowning of samples in water and evaporation water from water-saturated samples. These tests simulate the impact of rainfall on the insulation material and evaporation of water from the insulation material during a certain time period (e.g., during assembly or during operation, when the protective layer is damaged). The experimental results show the dependence of saturation insulation from direct contact with water in his drowning conditions and arrangement of heat-insulating materials on the water surface. In addition, the rate of evaporation of water in the water depends on the amount of thermal insulation material and its characteristics. Based on the results of such experiments, it is possible to make a choice of types of insulating materials suitable for Vietnamese climatic conditions.
Multi-criteria optimization of reinforced concrete beams using genetic algorithms
Authors: Tamrazyan Ashot , Alekseytsev Anatoliy
Published: July 2020

A strategy for finding optimal solutions for beam reinforced concrete structures according to several criteria has been proposed. The analysis and systematization of the optimization objectives for reinforced concrete framed systems is performed. To solve the problem, a modified genetic algorithm is used, which involves the selection of design options in a single iterative process into several databases containing solutions for each target criterion. When forming the current set of solutions, the migration of the best options from any base under consideration is allowed. As a general criterion of optimality, the J. Nash equilibrium principle is considered for penalties under failure to comply with constraints in relation to reinforced concrete structures.
Parametric vibrations of viscoelastic orthotropic cylindrical panels of variable thickness
Authors: Normuminov Bakhodir , Abdikarimov Rustamkhan , Mirsaidov Mirziyod , Khodzhaev Dadakhan , Mirzaev Bakhadir
Published: July 2020

In modern engineering and construction, thin-walled plates and shells of variable thickness, subjected to various static and dynamic loads, are widely used as structural elements. Advances in the technology of manufacturing thin-walled structural elements of any shape made it possible to produce structures with predetermined patterns of thickness variation. Calculations of strength, vibration and stability of such structures play an important role in design of modern apparatuses, machines and structures. The paper considers nonlinear vibrations of viscoelastic orthotropic cylindrical panels of variable thickness under periodic loads. The equation of motion for cylindrical panels is based on the Kirchhoff-Love hypothesis in a geometrically nonlinear statement. Using the Bubnov-Galerkin method, based on a polynomial approximation of deflections, the problem is reduced to the study of a system of ordinary integro-differential partial differential equations, where time is an independent variable. The solution to the resulting system is found by a numerical method based on the feature elimination in the Koltunov-Rzhanitsyn kernel used in the calculations. The behavior of a cylindrical panel with a wide range of changes in physico-mechanical and geometrical parameters is investigated.
Progressive collapse behaviour of compressed-bent rods of RC moment frames at sudden column removal
Authors: Savin Sergey
Published: July 2020

Due to the increasing incidence of disproportionate destruction of structural elements after the sudden removal of any supporting element, the number of studies of the resistance of structural systems to progressive collapse has grown significantly. However, among the research results presented in the scientific literature, there are practically no such studies in which an analysis of the resistance of compressed and compressed-curved reinforced concrete elements to disproportionate destruction would be performed. Therefore, in this paper, using the step-iteration method (Lira-CAD software) and non-linear stability analysis, we analyzed the behavior of the frame model when the column of the outer row was suddenly removed. In order to solve this problem, the analytical dependences are obtained for evaluating the stiffness of sections of compressed and compressed-curved elements. It has been established that the disproportionate fracture mechanism of compressed-bent elements of frame model is associated with a loss of stability.
Possible measures to reduce uneven deformation of floor structures of warehouse complexes
Authors: Rytova Tatyana , Rytov Sergey
Published: July 2020

The article discusses measures to reduce uneven deformation of floor structures of warehouse complexes. The main goal was to identify ways to reduce the unevenness of sediment in the floors of the warehouse. To obtain optimal reinforcement of the floor structure of warehouses, to reduce unevenness of floor sediments, two methods are used: increasing the rigidity of floor structures and (or) increasing the rigidity of the base due to the use of piles or its reinforcement. This article presents the experience of applying the technology for converting the construction properties of soils using crushed stone reinforcing elements (vibro stone columns) when installing floors in warehouses. This technology allowed to reduce the deformation of the base of the floors, to reduce their reinforcement.
Diagram of concrete dynamic deformation confined by CFRP jackets
Authors: Ubysz Andrej , Zhiharev Fedor , Chernik Vladimir , Dekhterev Denis
Published: July 2020

A review of the current state of the issue of describing the deformation of columns confined by CFRP jackets under of dynamic loading is carried out. The insufficiency of the study of elements under the influence of axial dynamic load is indicated. The dynamic increase factors (DIF) for concrete and CFRP, which are obtained by the results of existing experiments, are substantiated. Using the principle of the invariance of the potential energy of deformation of concrete at the time of its destruction under regime loading, a formula is obtained for determining DIF for ultimate relative strain of unconfined concrete. Based on the assumption of the same law of concrete deformation under static and dynamic loading, was obtained a diagram of concrete dynamic deformation confined by CFRP jackets. The diagram is valid in the range of strain rates 10−3-102 s−1. A comparison is made between a static diagram and a dynamic diagram derived from it. The characteristic of the main sections of the diagram is given. An increase in the strength and ductility of confined concrete at the initial stage of loading is obtained. At stresses equal to the tensile strength of limited concrete, its ductility is somewhat reduced. It was revealed that a significant increase in the bearing capacity of confined concrete begins at strain rates of 10 s−1 or more.
A numerical method for calculating round slabs based on generalized equations of the finite difference method
Authors: Uvarova Natalia , Turbinov Andrey
Published: July 2020

Round slabs are widely used in construction equipment. Currently, many different special structures are being built that have a circular shape in the plan. The article provides an analysis of thin isotropic circular slab in pure bending, the action of concentrated forces and slab loaded by a distributed load, supported at the centre. Different boundary conditions are considered. The initial differential equations of slab bending in polar coordinates are approximated by generalized equations of the finite difference method (MCR). The algorithm allows you to take into account the final discontinuities of the desired function, the right part of the original differential equations, as well as discontinuities of derivatives of these functions without thickening the grid and using contour points. It should be noted that for the Central point of the plate, differential bending equations and their numerical approximation in Cartesian coordinates are used, which makes it possible to determine the forces and movements at this point at any load.

The calculation algorithm is reduced to solving a system of differential-algebraic equations composed for field and contour points. The results of the calculation of slabs for these effects are presented. The reliability of the solution is confirmed by the convergence of results on some grids when the step is reduced, by comparing some solutions with existing ones, and by performing static checks. The advantage of this method is the ability to implement solutions with a small number of partitions.
Determination of the dynamic coefficient by the local damage of the element of steel trusses
Authors: Berger Maria , Tusnin Alexandr
Published: July 2020

An important role in the robustness analysis of damaged structures, is played by time during which local damage of the elements of the system occurs. Numerical studies have shown that the shorter the failure time of a particular farm element, the greater the dynamic forces arising in the structure. The time from the beginning of destruction to the complete failure of an element, which consists either in destruction or in loss of stability, is called the time of exclusion. The article describes the results of a series of numerical calculations of steel trusses as part of the building frame with local damage of individual truss elements. The influence of the time of exclusion of the element and the location of its damage on the value of dynamic coefficient was studied. The frame of the building is considered as a space frame, including not only trusses with local damage and the columns on which it relies, but also neighboring trusses, columns, bracing and purlins. This approach allowed to study the effect of local damage on the behavior of intact bearing structures. Based on the calculations, dynamic factors were established for the load acting on the truss with local damage and for the load on adjacent structures of the space frame. Recommendations are offered on constructive measures to increase the robustness of a building with steel trusses. The most unfavorable options for local damage of the trusses have been established. Recommendations are given on the assignment of dynamic coefficient for conducting a static calculation that takes into account the dynamic effects in the building frame with local damage of the truss.
Elimination of polarization effect in DC measurement of resistivity of CNT-cement composites
Authors: Tamov Murat , Pochinok Vladimir , Tabagua Georgiy R , Tamov Mukhamed
Published: July 2020

Multi-walled carbon nanotubes (CNT) may serve as electrically conducting fillers for traditional cement-based materials. Introducing small amount of CNT in the matrix of concrete turns the latter into a smart piezoresistive material applicable for the structural health monitoring of reinforced concrete structures. CNT–cement composites are subject to polarization during direct current (DC) resistance measurement. This phenomenon results in increase of electrical resistance of composites hindering their practical application. Suggestions for dealing with polarization usually include using alternate current measurements or applying direct current until resistance readings stabilize. This paper presents simple two-probe resistance sensing technique with DC being applied to the specimens as single square waves. Suggested approach is experimentally validated on the samples of CNT–cement composites. No polarization was observed in tested specimens when the periods between measurements were larger than 3 min. Such frequency of measurements is quite acceptable for monitoring the stress state of structures under static loading.
Intensity factors of homogeneous boundary value problem in angular area of the domain
Authors: Frishter Lyudmila
Published: July 2020

A relevant task in terms of ensuring reliable functioning of structures and constructions is studying structural areas with complex boundary shapes. Areas with geometrically non-linear shape of boundaries – angular cut-outs, cuts, and element connections with rupturing forced deformations – are characterized by singularities of the stress-strain state. In experimental research of areas with complex boundary shapes one must take into account the difference between stress intensity factors and deformation intensity factors. This paper describes a procedure for obtaining the stress-strain state in neighborhood of the angular cutout apex on the domain boundary using stress intensity factors and deformation intensity factors for a variety of homogeneous boundary conditions. In the angular cut-out area on the domain boundary, the stress-strain state is characterized by limit values of stresses and deformations, similar to stress intensity factors used with force criteria in fracture mechanics. Taking into account the ratios of stress and deformation intensity factors in experimental analysis of the stress-strain state in angular areas of structures is practically relevant for determining critical values of stress and deformation intensity factors.
Analysis of the reaction of reinforced concrete buildings with a varying number of stories with a seismic isolation sliding belt to an earthquake
Authors: Mkrtychev Oleg , Mingazova Salima
Published: July 2020

This article deals with the application of an active seismic protection system in the form of a seismic isolation sliding belt at the foundation level to ensure the seismic stability of a building or a structure. The type of seismic protection studied in this paper is simpler in design, cost-effective, and at least as efficient as widely used metal-rubber supports (MRS). Currently, the considered seismic isolation system does not have an adequate mathematical model to describe its operation in the building-seismic isolation-foundation-base system. The efficiency of using a seismic isolation sliding belt to ensure seismic stability of a structure was studied as exemplified by a cast in-situ reinforced concrete building with a varying number of stories (three-story, five-story, nine-story, sixteen-story building). As a result of the calculations, the relative displacements and accelerations and the intensity of stresses in the most loaded structural element were obtained. The analysis of the obtained results shows the efficiency of using a seismic-insolating sliding belt at the foundation level to ensure the seismic stability of buildings and structures.
Effectiveness of tuned mass damper system for steel frame building
Authors: Binh Pham Thanh , Tu Nguyen Van
Published: July 2020

The paper presents the analysis of using tuned mass damper system for reducing the response of structure subjected to lateral force, such as earthquake action. The assumed steel eight-story steel frame building is examined. The tuned mass damper system is modeled as 2 joint link in SAP2000, attached to top story of the building. The effect of tuned mass damper system for building under seismic excitation was evaluated by the results of maximum displacement and acceleration of the building. A sensitivity study was also performed to compare the structural response with different mass ratios. From the calculated results, discussions and conclusions are presented.
Decision making with visualizations: a cognitive framework for quality management in construction
Authors: Ivanov Nikolay
Published: July 2020

In conditions with unstable economy and a constantly increasing competition in the construction market, one of competitive advantages and factors of organization’s sustainable development is the existence of an effective QMS based on a risk-oriented approach for decision-making. Risk management is a process that is very important for construction industry enterprises and organizations. Each organization decides for itself how this process should be implemented. But in any case, an integral part of the process is the decision-making stage, which is most often representing a mechanism for managing corrective and preventive actions (CAPA). Analysis of various sources dedicated to the theory and practice of CAPA showed that several stages of the CAPA process cause difficulties for employees of quality management services of construction organizations. This article presents the author’s approach to a collecting and analyzing data stage implementation on detected inconsistencies and their root causes and as well as an implementation for stage of a list of corrective actions creation. The author proposes the concept of cognitive management of nonconformities based on visualization of data on nonconformities and their causes. The main result of the presented study is the nonconformity management technique aimed at improving the efficiency of the quality management system as a factor in sustainable development and increasing the competitiveness of Russian construction organizations.
Resistance enhancement of construction project organizational structure
Authors: Morozenko Andrey
Published: July 2020

This article integrate scientific studies in sphere of construction company organizational structure’s performance assurance in conditions of sharp and off-design changes of external and internal environment parameters. Organisational structure resistance is observed as a one of the most important properties of counteracting destructive effects of the external and internal environment. Objective and comprehensive description of resistance elements (reliability, durability, stability) is given. The paper substantiates a proposal to consider these organizational structure qualities from the standpoint of information science and the resource-based approach. This article particularly considers the question of organization structural stability, when its resistance is determined mainly by the organizational structure topology and not just by the qualities of system elements. This paper extends horizons of research and its borders, within which the organizational structure is able to implement its target function, release from particular resistance factors when analysing organizational structure and base on presented general approach. At the same time the paper does not renounce the studies of particular environmental factors impact on the organizational structure ability to resist their destructive effects.
Estimating the construction schools cost in Ho Chi Minh City using Artificial Neural Network
Authors: Dinh Cong Tinh , Nguyen Minh Quang
Published: July 2020

Construction cost is considered as one of the most important criteria in making decision for investment, especially in the idea formation stage. The paper provides a tool to determine the construction cost of the school during the conceptual design phase, when project information is still sketchy, not detailed yet. This research use artificial neural network techniques for estimating the construction schools cost. The model is based on the weight which set by the excel algorithm and the weight optimization method of the error back propagation. The excel algorithm is tested and optimized by using Statistical Package for the Social Sciences software. The basic model achieves accuracy 90.1% and the optimal model achieves 96.6% accuracy optimization. The optimal weight is used to build the cost estimation model with the automatic calculation program by the excel spreadsheet, which allows for updating the data value limited, updating weight when were adjusted.
Analysis and visualisation of stakeholder relationship in Offsite construction: Social Network Analysis approach
Authors: Ngoc Nguyen Bao , London Kerry A , Zhang Peng
Published: July 2020

While Off-site construction has emerged recently, its benefits have long been proved worldwide. Many hold that Off-site construction is re-structuring the industry, its supply chain and setting supplementary standards. Although stakeholder theory is prevailing in project management research, there is still a lack of in-depth research upon patterns of interrelationship and communication among Off-site construction stakeholders. Given that in Off-site construction project-based organisations are multi-level structures, stakeholders interact with each other not only within-level but also cross-level. To facilitate the adoption and diffusion of Off-site construction, there is a need to address patterns and find out the optimal mechanism for promoting inter-collaboration. Social Network Analysis is presented as a holistic approach to meet that need in a more quantitative and unambiguous way. Based on a critique of Off-site construction literature and Social Network Analysis theory, a conceptual framework is also proposed for Off-site construction stakeholder research themes and corresponding methodology. The aim of this paper is to contribute to a sound theoretical foundation for the development of a social network model and the understanding of the complex of connection and relationship among Off-site construction stakeholders.
Capital mobilization solutions for revenue increase of road transport infrastructure development in Viet Nam
Authors: Thi Tuyet Dung Nguyen , Phan Liên Trang Vương , Hùng Bùi Mạnh , Thị Tuyết Phạm
Published: July 2020

Road system play important role in socio-economic infrastructure. It should be prioritized and invested at a fast and sustainable pace, thus creating a premise for socio-economic development, ensuring national defence and security, and serving the industrialization and modernization process of the country. In recent years, many policies for investment capital mobilization of road traffic development are issued by Vietnamese government (such as diversification of investment capital, investment encouragement in public-private partnerships form, foreign direct investment and investment of private sector). However, the annual capital only meets more than 54% of demand. Based on the analysis of the current status and needs of capital for road construction, in this paper the author has proposed solutions to attract capital from the utilization of road transport infrastructure to sustainably develop the road system in Vietnam.
Analyzing the impact of accessibility on property price by using hedonic-price modelling for supporting urban land management towards TOD in Hanoi, Vietnam
Authors: Thanh Mai Nguyen Thi , Mai Chi Nguyen Thi
Published: July 2020

Land and property price are determined by a number of characteristics, such as house-related characteristics and neighborhood-related characteristics. Accessibility to urban services and infrastructure is considered as an attribute group with a strong influence on this value. These impacts are diverse and complex, inconsistent, depending on each case study. The paper desires to use the linear regression method to evaluate the impact of accessibility to urban services and transportation on property prices in Hanoi. Some models were set up based on our assumptions on the relationship between accessibility-related attributes and estimated for 4 zones in the south of Hanoi and use them to compare the differences among these zones. Conclusions about the relationship between property prices and accessibility to transit, car-accessibility and accessibility to public amenities will help to enhance many ideas in managing land development in new centers established from Urban Mass Rapit Transit (UMRT) interchanges under the TOD concept - compact development, mixed land use, and easy accessibility.
Organizational and technological sequence of the construction of an innovative type of hinged ventilated facade of a multi-storey building
Authors: Oleynik Pavel , Korchagina Yuliya
Published: July 2020

Introduction: Systems of insulation and decoration of external walls in the format of hinged ventilated facades have an increasingly significant impact on the achievement of consumer and functional quality indicators for architectural (structural, construction) systems of multi-story civil buildings. The achieved variety of constructive solutions, materials and methods of construction requires a meaningful system organization based on multi-criteria assessment of technological methods of design, manufacture and construction.

Materials and methods: a systematic analysis factors, generally accepted theoretical and applied research methods (analysis, systems approach, generalization) aimed at applying modern knowledge to achieve practical goals and solve specific problems of building.

Results: Description of the main features of the innovative facade system. Methods for ensuring the conditions for structural strength, durability and environmental sustainability ventilated facade.
Regression analysis of the calculation of the organizational and technological potential for the production of cold weather concreting
Authors: Lapidus Azariy , Khubaev Alan , Bidov Tembot
Published: July 2020

Concrete work in the winter and related organizational and technological decisions affect the efficiency of the construction project, both at the stage of technological design and at the stage of work. This work shows a review of research on organizational and technological solutions that affect the quality of monolithic structures in the construction of residential multistory buildings in the winter. We justified the choice of potential as the most optimal tool that will solve the problems posed in the study. We have identified the main regression coefficients for calculating the second-order regression equation. We performed data processing of production and technological modules and their correlation relationships identified in previous studies. The core matrix of the orthogonal central compositional plan is calculated. Variance of reproducibility has been determined. We have obtained the regression coefficients in this paper. We carried out the significance of these coefficients using the standard error. Further directions for the development of research into the potential of organizational and technological solutions for the production of concrete work in the winter were identified in this article. They were determined by determining the adequacy of this model.
The application of polypropylene fiber for reinforced concrete beams and slabs
Authors: Hiep Vu Hoang , Giang Do Truong , Tu Nguyen Trung
Published: July 2020

Currently there is no specific design standard for polypropylene (PP) fiber reinforced concrete structures. There are different conclusions on the bending strength of polypropylene fiber reinforced concrete structures. This paper presents some material properties of polypropylene fiber reinforced concrete. Based on the stress - strain state of the material, the stress diagram and the formula for calculation of the bending strength of the reinforced polypropylene fiber reinforced concrete with longitudinal bars structure were proposed. Bending strength of beams and slabs when using PP fiber were compared through examples and experiments.
A method of controlling thermal crack for mass concrete structures: modelling and experimental study
Authors: Le Hong-Ha , Vu Chi-Cong , Ho Ngoc-Khoa , Luu Van-Thuc
Published: July 2020

The control of the concrete temperature to prevent cracking can be viewed as principal goal in the design and construction of mass concrete. This paper researched on a novel technique for minimizing both the difference and the peak value of the temperature in mass concrete. Following this technique, the mass concrete is divided horizontally into two parts of different concrete mixtures but having the same strength grade. While the upper part is the normal heat concrete, the lower part can be considered as the low heat concrete which generate lower hydration heat than the upper part does. The influences of (i) concrete proportions of the layers; and (ii) thickness of the upper layer on the thermal behavior in mass concrete are two important aspects of the technique. Therefore, these two points represent important objectives of our present research. For this purpose, some numerical simulations with finite element method (FEM) and an in-situ experiment on a mass concrete block were performed. As a result, the simulated temperature field was validated by comparing with the experimental result and the principles of layers’ mixtures and thickness were drawn.
Construction of an axonometric outline of a curved surface of a part
Authors: Kravcova L I , Kostrubova I I
Published: July 2020

The article considers the geometric construction of the orthogonal isometry of a curved surface. To solve this problem, the authors propose to perform additional construction of the contour of the section of the surface in the orthogonal drawing and use the coordinates of the points of this section to construct an axonometric outline of the surface. The mismatch between the axonometric contour of the rotation surface and the corresponding contour of this surface in the projection drawing is illustrated. As a result, the proposed solution allows geometrically accurate construction of support and additional points of the axonometric contours of the revolution surfaces.
Composite low-water demand cements – one of the most promising and available technologies in terms of “Ecology” national project
Authors: Makarenko S V , Lozovskij B M , Khohryakov O V , Khozin V G , Baishev D I
Published: July 2020

In current article results of research of composite low-water demand cement (LWDC) based on Angarsk plant’s cement CEMII/A-F 32,5R, dump ash from TPP-10, marble powder from Sludjanskoj quarry and micro silica from LLC “Bratsk ferritic alloys plant” (Irkutsk region) are performed. Goal of the study is development of efficient ecology-friendly technology for high-quality cements with raw materials local to Irkutsk region. As a result of the study, technological, physical and mechanical properties of cement paste in fresh and hardened state were determined. Standard consistency W/B of LWDC-based cement pastes’ could be changed in range between 19 and 26%, and compressive strength of hardened cement paste can be variated from 22 to 60 MP. 2-stage 3-factor regressive analysis for compressive strength values of hardened cement paste at age 3,7,28 and after thermal curing was done, regression equations were obtained.
The using of liquid stone for the restoration and creation of copies of archaeological objects
Authors: Ya Mashovich A , Ruposov V L , Ineshin E M
Published: July 2020

It is an actual problem to investigate archaeological objects outside their native locations. New building materials make it possible to make the most realistic copy of archaeological objects, without destroying the object and extracting it from the natural environment. Liquid stone allows you to create objects with the imitation of color and texture of the original. This material can withstand high loads and it is used for prosthetics of the elements of archaeological structures. The technology of repetition of such objects allows making mass circulations of the most interesting archaeological objects. The technique makes it possible to restore objects from the remaining photos and description.
Thermodynamic calculations on system «Portland cement – water – carbon nanomodifier»
Authors: Smirnyagina N N , Tsyrenov B O , Urkhanova L A
Published: July 2020

The article presents the results of thermodynamic modelling in a cement-water-carbon nanomodifier system. A carbon nanomodifier contains fullerenes C60and C70. Thermodynamic calculations make it possible to evaluate the contribution of a carbon nanomodifier to the hydration process of Portland cement. Using thermodynamic calculations, changes in the phase composition and general properties of the system (total enthalpy, entropy) with the introduction of a carbon nanomodifier were determined.
Research of changes in the efficiency of renewable energy depending on external influences
Authors: Yu Shelekhov I , Smirnov E I
Published: July 2020

The article presents the results of a study of renewable energy sources (RES) based on solar panels, the operation of which took place in the Irkutsk region. The results of changing the efficiency of the solar panels depending on the use of light energy concentrators and the temperature of the panel itself are presented. The authors set the task of increasing the efficiency of the solar panels through the use of technical and constructive solutions.The experiments were carried out in the laboratory of IRNITU “Modern Heating Equipment”. For testing, we used a bench based on the TPM138 measuring regulator, an OVEN device of the IMS-F1.SH1 brand with a set of thermocouples., The subject of the study was two solar panels, on one of which a Fresnel lens was installed.The article formulates the purpose and objectives of the study, conducted research on the parameters of solar panels depending on the influence of the light energy concentrator and temperature changes on the panel itself, depending on external influences.As a result of the work, it was found that the efficiency of solar panels in the Irkutsk region in the summer period of time decreases by an average of 14.5%. And in the winter time by 7.5%. It is shown that to increase the efficiency of solar panels it is necessary to apply technical and constructive solutions that will reduce the payback period of solar engineering systems by 10-18%.
Schematic and structural optimization of group water supply systems
Authors: Chupin V R , Dushin A S
Published: July 2020

Group water supply systems (GWSS) are designed for centralized water supply of settlements located in waterless areas and remote from drinking water sources. GWSS are an object of increased attention, have a great social and environmental significance, require significant capital investments and financial resources for operation, ensuring the required reliability and manageability. Therefore, the issues of optimization of design solutions for the structure and parameters of structures are relevant and require improvement and development of methodological and software solutions to these problems. The paper proposes a method of redundant design schemes and a method of schematic and structural optimization based on a sequential and iterative solution of two problems: for a fixed value of flows in the graph of the redundant scheme, network parameters are optimized (pipeline diameters, heads, and the composition of pumping stations); with fixed network parameters, the problem of the distribution of water flows is solved in the GWSS.
Study of the possibility for reducing of environmental damage when the transition to alternative sources of heat supply systems in housing and communal services
Authors: Grebneva O , Lavygina O
Published: July 2020

Modern socio-economic conditions dictate increasingly stringent requirements for housing and communal infrastructure. When choosing a source of energy in heat supply systems, variants having maximum environmental efficiency are preferable. For an objective assessment of increasing of environmental safety degree, it is advisable to use a complex indicator that reflects the level of reduced environmental damage to the environment, in particular atmospheric air. In this work, the calculation of the prevented environmental damage for two types of fuel is made: natural gas and wood fuel (pellets). The calculation results showed when using natural gas instead of wood fuel for heat source that environmental and economic damage will be 64% less.
Justification of the parameters of developing water supply and sanitation systems based on their electronic models
Authors: Melekhov E S , Chupin R V
Published: July 2020

Most of the water supply and sanitation systems of modern cities and populated areas of the Russian Federation are characterized by significant physical depreciation, which is estimated at 60%., Significant moral depreciation, since some structures and pipelines are almost a hundred years old or more. At the same time, the replacement of old equipment is carried out annually at a rate of 2%. Such unsatisfactory rates of renovation are due to the lack of adequate funding and their irrational allocation to the construction of new ones, reconstruction and development of existing pipelines and structures. Obviously, to solve this problem, new and integrated approaches, new technologies for the design, construction and operation of water supply and sanitation systems are needed. One of such approaches is proposed in the work, based on digital technologies using electronic models of water supply and sanitation systems, on the basis of which methods for modeling operating modes and optimization methods for design solutions for the development of networks and structures have been developed. The results of applying the proposed technology on the example of water supply and sanitation in the city of Nizhneudinsk, Irkutsk region.
Using of the complex mobile station for heat and energy supply of residential villages, located on the protected areas
Authors: Tunik A A , Yu Tolstoy M
Published: July 2020

The results of studies of a complex mobile station for life support systems are presented. This station has the electric energy and thermal energy production functions, so as wastewater treatment and drinking water preparation. The production of electrical energy occurs through the conversion of solar energy and the use of microbial fuel cells. Thermal energy for the hot water system is obtained using solar collectors. A wastewater treatment plant is proposed based. The required number of complex mobile stations for life support systems, namely for wastewater treatment and hot water supply of the sports and recreation camp «Polytechnic», which is located at 17 km of the Baikal Highway, has been calculated. The calculations took into account the number of residents per season, water consumption and wastewater rate, the geographic location of the camp, the average number of cloudy days in the area and the number of sunny hours. The developed complex mobile station will ensure energy supply and disposal of wastewater from facilities located in recreational and protected areas without environmental consequences and violation of environmental and sanitary requirements. At the same time, the installation can be used on various types of objects.
Techniques for designing a mini house on a garden plot
Authors: Bolshakov A G
Published: July 2020

The problem is that comfortable housing is usually designed in such forms that make it inaccessible to people even with average incomes by russian standards. This leads to the task of reducing the volume and area of the house while maintaining the requirements for completeness of functions and architectural expressiveness. This social order is reinforced by the fact that the housing problem for people with middle and low incomes in Russia is solved in suburbia, on the territory of garden associations, where housing becomes an alternative to urban housing. The article solves the following problems: minimization of floor space, landscape-like architecture in conditions of a significant slope; development of expressiveness techniques for log cabins in combination with a wooden frame; architectonics of parts of a wooden building while ensuring maximum compactness.