bluuebunny/crossref_metadata_2025 huggingface dataset:
Low probability of intercept‐based OFDM radar waveform design for target time delay estimation in a cooperative radar‐communications system
Authors: Shi Chenguang , Wang Yijie , Wang Fei , Salous Sana , Zhou Jianjiang
Published: May 2019

In this study, a low probability of intercept (LPI)‐based orthogonal frequency division multiplexing radar waveform design strategy is developed for target time delay estimation in a cooperative radar‐communications system, where the communications base station (CBS) is able to receive and process the radar emissions. The basis of the LPI‐based radar waveform design strategy is to utilise the optimisation technique to design the transmitted waveform of a radar system for specified target time delay estimation accuracy in order to achieve enhanced LPI performance. The expression for Cramér–Rao lower bound is analytically derived and utilised as a performance metric for target time delay estimation performance. The resulting optimisation problem is solved by the approach of linear programming. Several numerical results are provided to verify the superiority of the proposed radar waveform design algorithm in terms of the LPI performance of the radar system. It is also shown that the radar transmitted power can be significantly reduced with the help from the CBS which plays a role of the bistatic radar receiver.
A decentralised bi‐level control approach to wind power regulation via thermostatically controlled loads
Authors: Xing H. , Zeng P. , Lin Z. , Wu Q. , Fu M.
Published: May 2019

This paper studies the wind power regulation problem by controlling a population of thermostatically controlled loads (TCLs) in smart grids. A decentralised bi‐level control approach is proposed, where the first‐level controller achieves load following based on wind power forecast, while the second‐level controller deals with the forecast error effectively using the frequency deviation information. Specifically, to realise the fair dispatch of wind power in a users’ comfort sense, the wind power following problem is formulated as a quadratic optimisation problem, which is solved by the first‐level controller. The second‐level adopts a local proportional controller to handle the frequency deviation caused by the forecast errors of wind power. The proposed algorithm converges fast and is decentralised in the sense that the TCLs conduct local computation and keep the parameters’ privacy from the aggregator. Simulations are given to show the performance of the proposed approach.
First stellar occultation by the Galilean moon Europa and upcoming events between 2019 and 2021
Authors: Morgado B. , Benedetti-Rossi G. , Gomes-Júnior A. R. , Assafin M. , Lainey V. , Vieira-Martins R. , Camargo J. I. B. , Braga-Ribas F. , Boufleur R. C. , Fabrega J. , Machado D. I. , Maury A. , Trabuco L. L. , de Barros J. R. , Cacella P. , Crispim A. , Jaques C. , Navas G. Y. , Pimentel E. , Rommel F. L. , de Santana T. , Schoenell W. , Sfair R. , Winter O. C.
Published: May 2019

Context. Bright stellar positions are now known with an uncertainty below 1 mas thanks to Gaia DR2. Between 2019–2020, the Galactic plane will be the background of Jupiter. The dense stellar background will lead to an increase in the number of occultations, while the Gaia DR2 catalogue will reduce the prediction uncertainties for the shadow path.

Aims. We observed a stellar occultation by the Galilean moon Europa (J2) and propose a campaign for observing stellar occultations for all Galilean moons.

Methods. During a predicted period of time, we measured the light flux of the occulted star and the object to determine the time when the flux dropped with respect to one or more reference stars, and the time that it rose again for each observational station. The chords obtained from these observations allowed us to determine apparent sizes, oblatness, and positions with kilometre accuracy.

Results. We present results obtained from the first stellar occultation by the Galilean moon Europa observed on 2017 March 31. The apparent fitted ellipse presents an equivalent radius of 1561.2 ± 3.6 km and oblatenesses 0.0010 ± 0.0028. A very precise Europa position was determined with an uncertainty of 0.8 mas. We also present prospects for a campaign to observe the future events that will occur between 2019 and 2021 for all Galilean moons.

Conclusions. Stellar occultation is a suitable technique for obtaining physical parameters and highly accurate positions of bright satellites close to their primary. A number of successful events can render the 3D shapes of the Galilean moons with high accuracy. We encourage the observational community (amateurs included) to observe the future predicted events.
Using group decision support systems in the preparation of real estate development projects
Authors: Gusakova Elena , Romanova Elena
Published: May 2019

The preparation and implementation of a real estate development project requires the adoption of a large number of diverse management decisions. For the preparation of decisions often attract experts. The opinions of many experts sometimes do not agree with each other and even are mutually exclusive. For their analysis using computer-based decision support systems (DSS). The article provides an analysis of several DSS, their applicability for the preparation of the project of real estate development. The results of the comparative experiment are also presented - the advantages and disadvantages of direct and indirect discussion of the project. It is revealed that the mediated written discussion with the use of information and communication technologies has advantages over direct discussion. It has been established that the quality of the discussion improves when there is a specially trained moderator who controls the process. Analysis of the features of the implementation of real estate development projects showed that there are no group decision support systems on the software market that can meet all the requirements necessary for the effective preparation and implementation of a real estate development project.
Investigating the capability of Smart City in Tehran
Authors: Danilina Nina , Majorzadehzahiri Alireza
Published: May 2019

The present research has sought to identify the features and capabilities of the smart city and their status in Tehran, identifying the strengths and weaknesses of this city in comparison with the smart city. For this purpose, first, the models and foundations of the smart city and its features presented by other researchers have been studied. The result of this study was to categorize Smart City features into six categories. The field survey of the topic by descriptive-survey method showed that these characteristics are confirmed by the statistical community as the characteristics of the smart city. With the ranking of 50 effective features, in addition to identifying important features in each category, 10 characteristics were identified as the most effective characteristics. The results show that among 50 characteristics, Tehran has only a relatively good status in eight characteristics. In other words, 84% of the characteristics in Tehran are not well-suited. The existence of such a situation cannot be ruled out by the integrated management factors on the affairs of the city of Tehran; there is no long-term plan for Tehran, and the relationship between people and government and the authorities is not related to partnership and cooperation.
Opportunities to improve the efficiency of design and construction
Authors: Rybakova Angelina , Kagan Pavel
Published: May 2019

This article discusses the current opportunities of «high-speed construction», which are based on technological, organizational and managerial approaches. For each acceleration approach under study, the mechanisms of action, advantages and disadvantages, as well as its distribution and scope, are identified. The most detailed method of «high-speed construction» based on the combination of design and construction works. The formation of this approach and the tools for its implementation are considered in detail. In this regard, the aim of the work is a detailed consideration of all modern methods of «high – speed construction», and the task-their structuring and interconnection. In the course of the study, the method of analyzing the directions of improving the efficiency of design and construction was applied. As a result, algorithms and tools for accelerating construction are formulated, as well as the impact of BIM-technology services.
The role of green space in the urbanization of Hanoi city
Authors: Le Minh Tuan , Cao Thi Anh Tuyet , Tran Nguyen Anh Quan
Published: May 2019

Rapid urbanization causes significant changes on the earth surface directly and internal itself temperature. The transformation of land use purposes crucially affects the surface temperature and exacerbates the effect of the negative heat island. It is necessary to develope a long-term strategy optimize urban cooling. In this study, the determinated object is Hanoi - city - a widen urbanized city in Vietnam. The authors proposed, defined and calculated the concept of cooling efficiency and threshold values. The results show that the surface heat capacity increases in proportion to the reduction of green space. Plots with excess temperature difference of the ground surface of 4.34 ℃ with reduced green space.
Application of anoxic phase in SBR reactor to increase the efficiency of ammonia removal in Vietnamese municipal WWTPs
Authors: Ha Quan Tran , Gogina Elena
Published: May 2019

Process removal nutrients, especially nitrogen – ammonia in municipal wastewater treatment is a challenger of design and operate wastewater treatment plant. Nowadays in Vietnam, technology SBR has been wide applied in biological wastewater treatment but the concentration of nitrogen – ammonia in treated water cannot achieve the discharge standard. For the purpose to reach the Vietnamese Standard A, the modification of SBR has been added the anoxic phase into operated cycle to create the denitrification’s environment and enhance performance of ammonia – nitrogen removal in municipal wastewater treatment at present and in the near future. The results of experiment shows that, the efficiency of N – NH4 removal in reactors sustainable in range 75 – 80% with the nitrogen loadings rate from 0.07 – 0.25 kg N – NH4/kg sludge/d. However, in 3 hours of anoxic phase, the value of specific denitrification rate is 0.10 – 0.15 kg N – NO3/kg sludge/d with the organic loadings rate in range 0.3 – 1.0 kg BOD/kg sludge/d and can reach the maximum is 0.2 kg N – NO3/kg sludge/d when the organic loadings rate increase to 2.0 kg BOD/kg sludge/d.
Pecularities of BIM adoption in Armenia
Authors: Ghazaryan Marine
Published: May 2019

The progressive penetration of Building Information Modelling (BIM) into the Architecture, Engineering and Construction (AEC) Industry varies in pace and profoundness from country to country depending on level of country development, industry maturity, scale of penetration, willingness of adoption in the institutional and political levels. This article is an attempt to reveal peculiarities and degree of BIM diffusion in developed and developing countries with the focus on case of Armenia. As methods of research was chosen literature review and questionnaire based survey among Industry companies of Armenia. Data collected using interviews and questionnaire surveys among construction and architectural enterprises, managers, owners, NGOs and regulating bodies of AEC industry were analysed. The development directions of the BIM implementation, industry efficiency enhancement issues, BIM related scientific research areas and more were reflected in structured study for Armenia.
Modern translucent materials and their impact on architectural forming
Authors: Timina Anastasiya , Yanova Regina , Popov Aleksey , Sorokoumova Tatyana
Published: May 2019

This work is devoted to the use of load-bearing elements made of translucent materials. To confirm the relevance of the study, regulatory materials and similar practices of using various materials as vertical and horizontal bearing elements were studied. Experimental experience was conducted to identify high indicators of the required characteristics of elements, which are considered as independent supporting structures. The object of the research is modern translucent materials. These materials have proven themselves as walling and auxiliary elements, their use as a supporting structure is not so important. However, in the course of the study it was revealed that translucent materials can be used as bearing elements without loss of strength and stability of the structure, which allows to visually facilitate the architectural appearance of the building. The subject of research is the influence of translucent supporting structures on the architectural shaping and the formation of the urban environment, by means of using the most visually lightweight structures. As a result of the study, it was concluded that it is possible and attractive to use translucent structures as load-bearing elements; however, there are drawbacks in a number of technological limitations, which directly affects the advantage of choosing not to benefit from translucent materials.
Review of energy saving and energy efficiency approaches applied in water sector in Russia
Authors: Makisha Nikolay , Shevchenko-Enns Eleonora
Published: May 2019

The article focuses on factors that might be crucial if an energy efficiency in the field of water supply and wastewater treatment is considered. There are most common drawbacks in maintenance of water supply and wastewater system described as well as the directions on the improvement of situation. The main directions of technological energy saving is the use of energy efficient technologies; energy efficient engineering solutions, and methods and equipment for regulating the operation of facilities and equipment.
Sequestration of carbon dioxide into building products based on the dolomite binder of carbonate hardening
Authors: Bakhtina Tamara , Lyubomirskiy Nikolay , Bakhtin Aleksandr
Published: May 2019

The paper covers the method of obtaining efficient structural heat-insulating and heat-insulating construction products based on sawdust and lime binder hardening in the medium of carbon dioxide. Building composites based on wood-cement compositions have several advantages compared to traditional concrete products, but at the same time there are several features such as incompatibility of cement binder with a certain type of wood due to the release of extractive substances by the wood and retardation of the binder which complicate the receiving technology. The use of a binder that was not affected by extractives, such as dolomite carbonate binder, greatly simplifies the production of finished products. Performed researches have shown the possibility of obtaining light building materials based on sawdust and lime binder of carbonate hardening. The process of obtaining samples in a specially designed mold takes 4-8 minutes; after that the samples achieve the required characteristics. The samples extracted from the mold do not require additional exposure and have specified geometrical and physico-mechanical parameters.
Role of basalt dust in the formation of the modified gypsum structure
Authors: Petropavlovskaya Victoria , Zavadko Maria , Petropavlovskii Kirill , Buryanov Aleksandr , Novichenkova Tatiana , Pustovgar Andrey
Published: May 2019

Waste disposal in the production of building materials and the organization of waste-free technological processes require a large amount of multilateral research. The application of basalt dust in the production of gypsum materials has been little studied. The paper investigated the effect of basalt dust - waste production of basalt fibers, on the working mixtures and the properties of hemihydrate of calcium sulfate paste (standard consistency, setting time of gypsum dough, water absorption of the resulting gypsum stone). It is known that the addition of basalt waste has a positive effect on strength, but there is no data on its effect on the rheological properties of gypsum mixtures. It was revealed that the introduction of basalt dust into the composition of the gypsum composite contributes to the change of the plaster mix rheology and of the properties of the gypsum structure. This must be taken into account when selecting optimized formulations of working mixtures on the hemihydrate of calcium sulfate.
The FRP and TRC strengthening of the masonry structures
Authors: Granovsky Arkady , Simakov Oleg , Dzhamuev Bulat
Published: May 2019

The use of external reinforcement based on carbon fibers is technically and economically justified to strengthen concrete structures, which is confirmed by years of experience. The use of this method of reinforcement for masonry structures has significantly less history and, accordingly, experience. However, experimental and site specific efficacy of the use of external reinforcement in the amplification of the pillars of masonry by the device holder has been proven. The experiments of strengthening of a brickwork carried out earlier, as well as the developed theory of calculation, concern application of a full-bodied brick. Given the volume of construction of large-format ceramic stone, the task of strengthening structures from it becomes more urgent every year. In order to solve this problem, the present experimental studies were carried out – experimental studies of the clip effect on the fragments of brickwork with the strengthening of the external reinforcement system based on carbon fibers. In addition to studies of the influence of the size of bricks and the presence of voids, there was a study of the possibility of strengthening the samples with a cross-section size ratio of more than 2. In this case, carbon through anchors were mounted in the Central part of the samples. The test results obtained characters of destruction of specimens, the ultimate load-bearing capacity, made the appropriate conclusions.
Durability of fine-grained limestone concrete
Authors: Belov Vladimir , Barkaya Temur , Kuliaev Pavel
Published: May 2019

Production of effective building materials of high-density and high-durability is connected with the development of methods of modification of such materials on macro-, micro- and nanostructural levels. Presently the application of finest ingredients in admixture compositions such as limestone filler produced from local quarries is viewed as a primary task of cost reduction in limestone concrete manufacturing. The efficiency of limestone filler to enhance the durability of fine-grained limestone concrete is shown in tests performed. Limestone half inert filler conjointly with superplasticizer are found to enhance crack-resistance and reduces creep strains, which makes fine-grained limestone concrete the most effective and long-standing material. Knowledge of the stress-strain distribution in concrete with limestone fines under compression is important for the design of certain kinds of reinforced thin-walled concrete structures, such as shells, membranes and domes. These structures are manufactured with addition of both limestone filler and superplasticizer performing synergetic effect which leads to increasing a level of crack causing stresses.
Parameters of the safety and fall arrest nets in buildings under construction
Authors: Brodskiy Victor
Published: May 2019

There are terms of industrial safety provision for construction and reconstruction of building and structures for various purposes through the use of protection netting devices, which in some cases is the only possible means of preventing industrial injury in the event of a person or objects possible fall from height. Given are basic component elements of devices in which synthetic netting materials are proposed as the most pacing factor for required degree of protection. Considered are protection netting devices’ key parameters allowing ensuring guaranteed arresting of items falling from certain height, as well as required length and angle for brackets installation with required distance between them. Based on derived dependences, established was a family of items’ descent trajectories for various components of horizontal speed and values of initial center-of-gravity position that are shown on respective nomograph. A nomograph was also built allowing identifying under given values the bracket length and angle of its installation with the purpose of ensuring arresting of falling item. To reduce the probability of a falling human collision with supporting structures of a protection netting device, recommended minimum distance between brackets was set.
Evaluating the Effectiveness of Continuous Composite Beams for Steel-Concrete Bridges and Control Concrete Cracks of the Supports at an Early Age
Authors: Nguyen Trong-Chuc , Huynh Trong-Phuoc , Ho Nguyen-Trong , Abdun Noor Al-Amin
Published: May 2019

This study presents a solution to contextualized span bridges constructed with composite steel girders with reinforced concrete slabs by reinforced concrete. This kind of structure, in comparison with a simple span, has many advantages as overcoming internal forces, reducing large displacements and cutting the number of expansion joints. Also, numerical simulations were conducted to evaluate the effectiveness of continuous composite beams for steel-concrete bridges and control of cracking of concrete at the supports at an early age. The models and conclusions in this paper can provide safety guidance for construct composite steel girder bridge in Vietnam.
Standardization of requirements to operation of buildings and facilities
Authors: Mamin Alexandr , Kodysh Emil , Bobrov Vladimir
Published: May 2019

Safe operation, reliability and durability of capital facilities (hereinafter – CF) are becoming more and more topical.

All phases except operation (including all types of maintenance and repairs) and demolition were covered by regulatory requirements, while operation as the longest phase in CF life and the final stage - demolition were not included into regulations until recently. There were industry specific codes for nonproduction and industrial buildings and facilities and documents derived from them, but they were inconsistent, lead time to repair differed even for similar structures and operation conditions and these discrepancies did not allow setting the specific frequency of repairs which resulted in neglected defects and damages shortening the life of buildings and structures or causing accidents.

In 2015, the authors, in team with other experts, developed SP 255.1325800.2016 “Buildings and structures. Rules of operation. Key provisions” (hereinafter - SP 255), setting general requirements to operation of buildings and structures under regular conditions, but the diversity of buildings’ functions required the development of numerous codes of practice derived from SP 255 and some of them were drafted in 2016-2018.

Codes of operation practice will (if elaborated) contribute to the reduction of operation and maintenance costs and ensure required safety of capital facilities.
Study of fireproof properties of textile materials safe when in contact with human skin
Authors: Konstantinova Natalia , Eremina Tatyana , Kuznetsova Irina
Published: May 2019

The methods of surface fire retardant treatment of textile materials (TM) and the chemical basis of the fire retardants used are considered. The possibility of developing a fire retardant composition for tissues that would not adversely affect the human skin upon contact has been studied. To determine the degree of danger of contact and of the penetration of chemicals through skin in contact with the fireproof TM, special studies were conducted to study the local irritating effect and resorption of the composition according to special developed laboratory methodological instructions. As the result the evidence was found that the irritating effect of the fire retardant composition developed on the skin and mucous membranes of the eyes of experimental animals was not detected. Comparative thermo analytical studies showing the effectiveness of the fire retardant action of the composition developed on the main stage of thermal decomposition of cellulose-containing TM are presented. Thus, the development of a fire retardant composition based on phosphorus-containing compounds and urea compounds and the selection of the optimum ratio of stabilizers for the processing of decorative and finishing fabrics with safe contact with human skin can be one of the effective ways to solve the problem under consideration.
Features of mathematical modelling in the analysis of console-type structures
Authors: Orlov Viktor
Published: May 2019

The article deals with the mathematical model of console-type structural elements. The dynamic load is presented as quasi-static one. The differential equation of bending of an object is nonlinear and has movable singular points in which the solution has discontinuity. From a physical point of view, the object will break (collapse) in this place. The application of the majorant method to the solution of the problem allows, in contrast to the classical approach, establishing the boundaries of the solution area and to construct an analytical approximate solution to the problem with a given accuracy. As a result, it’s possible to calculate the displacement at any point of the cantilever structure and estimate the stress-strain state of the object.
To the problem of development of low-rise housing in Russia
Authors: Tusnina Valentina , Yakovleva Ekaterina
Published: May 2019

The issue of providing the population with comfortable and affordable housing has always been rather acute in our country. The solution to this problem, taking into account the trends in the creation and transformation of the urban environment into the most reliable, comfortable and affordable, may be the mass construction of low-rise housing. Of primary importance in solving the problem of mass construction of low-rise housing is the maximum industrialization of construction and installation work, which should be provided at the design stage in order to reduce labor costs at the construction site, where only assembly and installation work from structures of full factory readiness should be performed. In this aspect, the unification in the design and production of building steel structures will allow creating a system of typical design of civil buildings, including low-rise residential buildings, on the basis of steel frames for mass construction and solving the problem of affordable and comfortable housing in Russia.
The consideration of compliance of structural joints in calculation of large panel buildings
Authors: Malakhova Anna , Davletbaeva Daria
Published: May 2019

The article presents and analyzes the design solutions of horizontal and vertical joints, as well as methods for determining the coefficient of compliance joints. It also presents the numerical determination of the coefficients of compliance of the horizontal mortar joint in accordance with the standards for the design of large-panel buildings. It is shown that the compliance of the joint on the embedded parts consists of the compliance of the connecting element, embedded parts of the wall panels, namely the metal plate and reinforcing bars of the anchors, as well as the compliance of the welds. In this case, the joint operates in a complex stress-strain state. It is noted that the most difficult is to determine the compliance of embedded parts. Three calculation methods have been developed for the numerical determination of the compliance coefficients of anchor bars under the action of tension (compression), bending moment and shear forces on the embedded part. The deformation of the welds was defined in MGSU in the framework of the experimental research of the work of the vertical seam with embedded parts. The article presents a graph of the deformation in the weld on the applied vertical load on the test piece.
Variable moduli of soil strain
Authors: Sultanov Karim , Loginov Pavel , Ismoilova Sabida , Salikhova Zulfiya
Published: May 2019

The experimental diagrams between stress and strain components for soft soils are non-linear. Nonlinear diagrams qualitatively differ for soils of undisturbed and disturbed structures. It is believed that the manifestations of nonlinear properties of soil are associated with micro-destruction of soil structure under compression and, therefore, with changes in its mechanical characteristics under strain. It follows that the modulus of elasticity, Poisson’s ratio, viscosity and other mechanical parameters are the variables in the process of soil strain. Based on this, from the experimental results given in scientific literature, the changes in the modulus of elasticity and plasticity of soil are determined depending on the values of compression strain. In the process of static and dynamic compression of soil it is almost impossible to determine the boundaries of elastic and plastic strains in soft soil. So, the modulus under soil compression is called the strain modulus. From published results of experiments on dynamic and static compression of soil the most informative ones have been selected. Processing the selected compression diagrams of soft soil, the secant moduli of strain for loess soil and clay have been determined. It is established that the moduli of strain of clay and loess soil under static and dynamic strain vary depending on the rate of strain, the state of the structure and the level of compressive load.
Low-amplitude dynamic tests of fine gravel in a resonant column
Authors: Ter-Martirosyan Zaven , Sobolev Evgeny , Anzhelo George
Published: May 2019

Construction of industrial and civil buildings, taking into account the dynamic effects on the foundations, requires special experiments on the mechanical properties of soils. This article presents the results of studying the dynamic properties of coarse gravelly soils using the resonant column method. These studies are relevant, since the determination of the dynamic properties of coarse-grained soils under laboratory conditions is associated with a restriction on the size of the fractions in the sample volume. This circumstance leads to the fact that at the moment most of the laboratory tests of the dynamic properties of coarse-grained soils are performed on smaller aggregate fractions, which, in general, significantly reduces the resulting mechanical properties of soils. It does not reflect the real operation of the foundation of buildings during dynamic effects. This paper presents a description of the available laboratory equipment, the sequence of preparation of samples of coarse grained crushed stone soil and sample assembly in the working chamber of the installation. The article contains the main graphs characterizing the change in shear modulus and damping coefficient depending on shear deformations. It is noted that the results obtained are particularly relevant for modeling the dynamic effects of natural and man-made character on the foundations of industrial and civil buildings, the bases of which are composed of coarse-grained soils. Dynamic parameters considered in this paper, can and must be used in numerical calculations by finite element method with the use of modern groundwater models in geotechnical software systems.
Deformation of cylindrical shells of steel 45 under complex loading
Authors: Cheremnykh Stepan , Zubchaninov Vladimir , Gultyaev Vadim
Published: May 2019

Reviewing the numerical simulation of the process of non-proportional elastic-plastic deformation of steel 45 by a knot of constant curvature, taking into account the complex nature of deformation under complex subcritical loading by axial compressive force and torque for a thin-walled circular cylindrical shell. The theory of Quas and simple processes of A. A. Ilyushin and the mathematical model of V. Zubchaninov were applied taking into consider the parameters of the complex loading for plane trajectories To assess the accuracy of accepted theories, the simulation results are compared with experimental results, received on the automated complex СNcomputer in the laboratory of the faculty of «Strength of materials and theory of elasticity and plasticity» of the Tver state technical University. Was introduced the scheme of calculations disproportionate plastic deformation of steel 45 using the proposed mathematical model showed a satisfactory result and recommended for further use. Remarks, that in the described processes the lack of some parameters complex loading in approximations reduces the accuracy of the final calculated values, differences significantly compared to the experimental data.
Non-linear settlements of shallow foundation
Authors: Yarkin Viktor , Kukhar Hanna , Lobacheva Nataliia
Published: May 2019

This article proposes a method for determining the nonlinear settlements of the foundation, based on the method of layer-by-layer summation, which allows to determine the settlement of the foundation until the base bearing capacity is exhausted, taking into account the heterogeneity of the geological structure of the soil massif and the presence of weak underlying layers of soil. The recommended equation for determining the coefficient ks is given, which allows you to approximate almost any curve of the dependence of settlement on pressure, taking into account the properties of the soil base, size, shape and depth of the foundation. It carried out a comparative analysis of the proposed method with the results obtained experimentally and other calculating methods.
Thickness dimensions of the contact layer of soil-rigid body interaction
Authors: Khusanov Bakhtiyar , Rikhsieva Barno
Published: May 2019

Solution of the problems of longitudinal interaction of underground pipelines with soil in a one-dimensional statement requires precise measurements of the thickness of the soil layer contacting with the pipeline. In order to determine the dimensions of the contact layer of soil, the behavior of soil medium under shear interaction of a rigid body with soil is studied. Under straining in soil medium, structural changes denoted by the coefficient of structural destruction are taken into account; the condition of complete adhesion is taken in the contact rigid body – soil boundary. The interaction process under consideration is investigated numerically by the finite difference method. The results of the calculations are presented in the form of graphs and are analyzed. From the obtained results, the maximum values of the thickness of soil contact layer are determined as well as the layers with the corresponding degree of structural destruction depending on the geometric dimensions of the rigid body.
Seismic pads to protect buildings and structures from bulk seismic waves
Authors: Vershinin Vladislav , Javkhlan Saruul , Saidmukaram Suhaibi
Published: May 2019

The issues of using seismic pads to protect buildings and structures from bulk seismic P and S waves are analyzed. Considered are historical counterparts including the famous Imperial Hotel in Tokyo. The prospects are noted for the use of seismic pads providing the best protective properties and greater durability, comparable to the lifetime of the entire structure, as well as, most importantly, the protection of the structure and its foundation structures that remain unprotected using various types of seismic isolators.
To determine the optimal size of the elements of complex overlap
Authors: Kuznetsov Vitaly , Shaposhnikova Yulia
Published: May 2019

The article discusses the possibilities of optimizing the size of elements of reinforced concrete ceilings along. The optimization of the overlap consists in finding such parameters of the reinforced concrete slab, profiled flooring and steel beams, in which their strength is fully used. For ceilings with steel beams included, the dimensions of the sections of the elements and their strength characteristics are determined by the requirements of the limit states of the second group (deflections), and the calculation of the forces in the slab and beams and strength calculations are performed taking into account the geometric and strength characteristics established from the calculation of deformations. To clarify the features of the calculation and verification of the main provisions, a numerical experiment was carried out, where the center cell of the steel concrete slab along metal rolling beams was selected as the object of study. Formulas are obtained for determining the forces using predetermined dimensions of the components of the overlap based on satisfying the requirements of the 2 groups of limit states. These studies can serve as a basis for further research on the search for optimal parameters of complex floors.
Features of the port retaining structure calculations
Authors: Sidorov Vitalii , Vanina Yuliya
Published: May 2019

Contrary to the considerable experience of designing, construction and operation of hydraulic construction of the bulwark type, there are still emergencies that exceed the normative values of deformations, displacements, rotation angles, loss of stability both during the staged construction and at the completion of construction. The question of taking into account the interaction of various complicating factors in the system “retaining structure-soft saturated soil base” is currently fundamental when choosing the type of element of structures, technology and the time of their construction. As a task, the interaction of a thin-walled bulwark on a soft saturated soilbase with the ice and seismic impacts was considered. Numerical research performed using PLAXIS 2D. Prediction of the interaction of the berth construction with the soil base, taking into account the variety of loads and impacts, made it possible to identify exceedances of normative values of forces, bending moments, displacements, which requires further consideration of the issues of ensuring the safety operation phase of the berthing construction. The errors of designers to unfinished consolidation of soils, the non-linear behavior under various impacts will lead to emergency situations, especially in hydraulic engineering. The results of the article show the need to take into account the rate of loading of the base for correct accounting of the bearing capacity of soft soils.
Evaluation of the reliability of reinforced concrete beams on a stochastically inhomogeneous elastic foundation under the action of a non-stationary random load
Authors: Deminov Pavel , Danilkiv Andrey
Published: May 2019

The results of the evaluation of the reliability of reinforced concrete beams lying on an elastic foundation are presented. The load on the beam is considered as a non-stationary random function, the elastic properties of the foundation are described as a stationary random function. Beam stiffness is considered as a random variable depending on the cubic strength of concrete. To solve the beam bending equation on an elastic foundation with random properties and a loaded non-stationary random load, the small parameter method and the method of spectral representations are used. The obtained probability characteristics of the probability density distribution of bending moments allow us to find the probability of failure of a reinforced concrete beam on an elastic stochastically inhomogeneous foundation.
Calculation of structural-inhomogeneous multiply connected shell structures with viscoelastic elements
Authors: Mavlanov Tulkin , Khudainazarov Sherzod
Published: May 2019

Using the basic relationships of the hereditary theory of viscoelasticity and asymptotic methods, the problem of natural oscillations of structural-inhomogeneous, multiply connected, axisymmetric shell structures is reduced to an effectively solvable mathematical problem of complex eigenvalues, in which approximate engineering methods are proposed.
Working capacity of aluminum alloys in structure elements
Authors: Shuvalov Aleksandr , Katanina Alla , Kornev Oleg , Kovalev Mikhail
Published: May 2019

Mechanical properties of specimens were researched for model analysis of stress-strain behavior in the stress concentration zone for plate structures using aluminum alloys. Traditional and new structure materials including Russian (1915T and 1565ch) and foreign (6082 – Russian analogue AD35) developments with different alloyage systems (Al-Mg, Al-Mg-Si and Al-Zn-Mg accordingly), strengthening methods, corrosive resistances and welding capacities are studied. Strain and fracture resistance is shown for axial and eccentric tension and for impact bending in the temperature range from -70 to +20°C. Acquired results allow us to designate loads reasonably for structure design using aluminum alloys and estimate their durability.
Faultlessness of composite enclosing structures with thin-sheet linings and effective thermal insulation
Authors: Bobryashov Viktor V. , Bobryashov Viktor M. , Bobryashova Anastasiya , Bushuev Nikolay
Published: May 2019

Fencing composite structures with thin-sheet metal cladding and effective thermal insulation are widely used. They are especially effective in hard to reach, remote, seismic areas, in areas with harsh climates. There is a problem of estimating the real random loading of snow, wind, ice, temperature loads and others according to Roshydromet, when the strength, heat engineering, dielectric, and other structural parameters are random and changes in which from the allowable area lead to failures.The paper provides an assessment of the reliability of enclosing structures of buildings based on quantitative signs of impacts (wind, snow and permanent), as well as the results of statistical evaluation of factory acceptance tests. This paper discusses to exhaust the resource - the strength of the middle layer of the structure during shear.
GIUH-Nash based runoff prediction for Debarwa catchment in Eritrea
Authors: Gehbrehiwot Anghesom , Kozlov Dmitry
Published: May 2019

Correct assessment of river flow is necessary to resolve a wide range of problems in the management and use of water resources. Recently, research towards the use of geomorphologic instantaneous unit hydrograph (GIUH) coupled with other conceptual models approach for flood prediction from ungauged catchments has been intensified. Widespread accessibility to geographic information system and remotely sensed imagery which are powerful tools for acquiring model inputs is one possible reason. This study, therefore, aims at direct surface runoff (DSRO) prediction using the geomorphologic instantaneous unit hydrograph based Nash model (GIUH-Nash) from ungauged catchment. DEM obtained from Shuttle Radar Topography Mission (SRTM) having 30 m resolution is used to generate the catchment’s physiographic and geomorphologic characteristics with the help of quantum geographic information system (QGIS). Based on this information, the GIUH-Nash model is used to simulate DSRO for different storm events. A visual comparison of observed values to predicted values of the runoff hydrographs as well as statistical indices shows that DSRO could be predicted with reasonable accuracy provided complete understanding of the model development and it’s evaluation procedures are properly followed. In respect of this, some key aspects that affect the performance of the model have been suggested.
Filtration in porous rock with initial deposit
Authors: Osipov Yuri , Galaguz Yuri
Published: May 2019

The problems of underground fluid mechanics play an important role in the design and preparation for the construction of tunnels and underground structures. To strengthen the insecure soil a grout solution is pumped under pressure in the porous rock. The liquid solution filters in the pores of the rock and strengthens the soil after hardening. A macroscopic model of deep bed filtration of a monodisperse suspension in a porous medium with a size-exclusion mechanism for the suspended particles capture in the absence of mobilization of retained particles is considered. The solids are transported by the carrier fluid through large pores and get stuck at the inlet of small pores. It is assumed that the accessibility factor of pores and the fractional flow of particles depend on the concentration of the retained particles, and at the initial moment the porous medium contains an unevenly distributed deposit. The latter assumption leads to inhomogeneity of the porous medium. A quasilinear hyperbolic system of two first-order equations serves as a mathematical model of the problem. The aim of the work is to obtain the asymptotic solution near the moving curvilinear boundary - the concentration front of suspended particles of the suspension. To obtain a solution to the problem, methods of nonlinear asymptotic analysis are used. The asymptotic solution is based on a small-time parameter, measured from the moment of the concentration front passage at each point of the porous medium. The terms of the asymptotics are determined explicitly from a recurrent system of ordinary differential and algebraic equations. The numerical calculation is performed by the finite difference method using an explicit TVD scheme. Calculations for three types of microscopic suspended particles show that the asymptotics is close to the solution of the problem. The time interval of applicability of the asymptotic solution is determined on the basis of numerical calculation. The constructed asymptotics, which explicitly determines the dependence on the parameters of the system, allows to plan experiments and reduce the amount of laboratory research.
Experimental researches of hydraulic vacuum breakdown devices of siphon outlets of pumping stations
Authors: Shomayramov Muzaffar , Norkulov Behzod , Rakhmanov Javlonbek , Tadjiyeva Durdona , Suyunov Javlonbek
Published: May 2019

The paper presents the results of experimental researches of siphon outlets, which are used at large machine canals. It has been justified that siphon water outlets of the pumping stations operate in different conditions that siphon spillways at hydroelectric power plants and the mode of their operation have a significant impact on the operation of the pump. In terms proposed by us, the siphon has a constant width, equal to the diameter of the pipeline. The siphon length is reduced by 4.5 m. The height of the ridge is reduced so that the crosssectional area remains equal to cross – sectional area of the pipeline. The descending brunch is made with the same slope m= 1.6, the cone angle of the diffuser is a= -6°. The bottom of the outlet section of the siphon is raised by 2.5 m against the previous mark, the ceiling is deepened below the minimum water level by 1.0 m., and then smoothly turns up and out for 0,5m below the minimum headwater level of the upstream. The proposed version of the siphon when testing on the model was fully included at the maximum flow rate Q=18 m3/s. at a water temperature of 22°C.
Interconnection of influent channel and pumping station units
Authors: Glovatskiy Oleg , Djavburiyev Temur , Urazmukhamedova Ziyoda , Gazaryan A. , Akhmadov Farkhod
Published: May 2019

This paper reports on the results obtained the priority recommended strategy for carrying out reconstructive work aimed of the reliability control and safety of Jizzakh main pumping station. It has been established that the safe operation level of Jizzakh main pumping station is supported under the following conditions: The watermark in the pump station forebay are not lower than 314.55 and watermark in the headpond is not higher than 337.80 and not lower than 336.90 for the main units. At the station, no more than 5 “main” and 2 “subsidiary” units work, one “main” unit must be constantly in reserve.