bluuebunny/crossref_metadata_2025 huggingface dataset:
River fragmentation and flow alteration metrics: a review of methods and directions for future research
Authors: Jumani Suman , Deitch Matthew J , Kaplan David , Anderson Elizabeth P , Krishnaswamy Jagdish , Lecours Vincent , Whiles Matt R
Published: November 2020

Rivers continue to be harnessed to meet humanity’s growing demands for electricity, water, and flood control. While the socioecological impacts of river infrastructure projects (RIPs) have been well-documented, methodological approaches to quantify river fragmentation and flow alteration vary widely in spatiotemporal scope, required data, and interpretation. In this review, we first present a framework to visualise the effects of different kinds of RIPs on river fragmentation and flow alteration. We then review available methods to quantify connectivity and flow alteration, along with their data requirements, scale of application, advantages, and disadvantages. Finally, we present decision-making trees to help stakeholders select among these methods based on their objectives, resource availability, and the characteristics of the project(s) being evaluated. Thematic searches of peer-reviewed literature using topic-relevant keywords were conducted on Google Scholar. The bibliography of selected papers was also reviewed, resulting in the selection of 79 publications. Papers that did not define or apply a specific metric were excluded. With respect to fragmentation, we selected papers focused on instream connectivity and excluded those dealing with overland hydrologic connections. For flow alteration, we selected papers that quantified the extent of alteration and excluded those aimed at prescribing environmental flows. The expected hydrological consequences of various RIP types were ‘mapped’ on a conceptual fragmentation-flow alteration plot. We compiled 29 metrics of river fragmentation and 13 metrics to flow alteration, and used these to develop decision-making trees to facilitate method selection. Despite recent advances in metric development, further work is needed to better understand the relationships between and among metrics, assess their ecological significance and spatiotemporal scale of application, and develop more informative methods that can be effectively applied in data-scarce regions. These objectives are especially critical given the growing use of such metrics in basin-wide conservation and development planning.
Weather regimes and patterns associated with temperature-related excess mortality in the UK: a pathway to sub-seasonal risk forecasting
Authors: Huang Wan Ting Katty , Charlton-Perez Andrew , Lee Robert William , Neal Robert , Sarran Christophe , Sun Ting
Published: November 2020

Non-optimal temperatures, both warm and cold, are associated with enhanced mortality in the United Kingdom (UK). In this study we demonstrate a pathway to sub-seasonal and medium range forecasting of temperature-related mortality risk by quantifying the impact of large-scale weather regimes and synoptic scale weather patterns on temperature-associated excess deaths in 12 regions across the UK. We find a clear dominance of the NAO− regime in leading to high wintertime excess mortality across all regions. In summer, we note that cold spells lead to comparable cumulative excess mortality as moderate hot days, with cold days accounting for 11 (London) to 100% (Northern Ireland) of the summer days with the highest 5% cumulative excess mortality. However, exposure to high temperatures is typically associated with an immediate but short lived spike in mortality, while the impact of cold weather tends to be more delayed and spread out over a longer period. Weather patterns with a Scandinavian high component are most likely to be associated with summer hot extremes, while a strong zonal jet stream weather pattern which rarely occurs in summer is most likely to be associated with summer cold spells.
An exact power series representation of the Baker–Campbell–Hausdorff formula
Authors: Moodie Jordan C , Long M W
Published: November 2020

An exact representation of the Baker–Campbell–Hausdorff formula as a power series in just one of the two variables is constructed. Closed form coefficients of this series are found in terms of hyperbolic functions, which contain all of the dependence on the second variable. It is argued that this exact series may then be truncated and be expected to give a good approximation to the full expansion if only the perturbative variable is small. This improves upon existing formulae, which require both to be small. Several different representations are provided and emphasis is given to the situation where one of the matrices is diagonal, where a particularly easy to use formula is obtained.
Estimation of porosity of coatings based on sol of silicate paint
Authors: Loganina V I , Mazhitov Y B
Published: November 2020

Information on the properties of the sol of silicate paint is given. The porosity of coatings was studied. The fractal pore size of the coating was indentified. It was found that sol-silicate coatings are characterized by a high fractal pore dimension. The protective properties of the coatings evaluated. A decrease in water absorption values was observed during capillary suction of mortar samples stained with sol by silicate paint in comparison with samples stained with silicate paint. Information on the properties of the sol of silicate paint and coatings based on it is provided.
Organic composite binder improving the physical and mechanical properties of low-strength stone materials
Authors: Leskin A I , Aleksikov S V , Gofman D I
Published: November 2020

Based on the results of research and practical tests, the authors have developed a composition and proposed a technology for preparing an organic composite binder capable of deep penetration into pores of low-strength stone material with formation of a hydrophobic well-retained layer on its surface, which provides improvement of the main strength characteristics of the stone. Results of experimental studies are presented, optimal concentration of OCB and minimum processing time are determined. Practical recommendations are given for using the obtained strengthened material, which can act as a full-fledged independent working layer of road structure, as well as a component of asphalt concrete and cement concrete mixtures.
Quality Improvement of semi-dry pressing ceramic bricks from low-quality raw materials by the directional additives
Authors: Ilina L , Tatski L , Baryshok L
Published: November 2020

The advantages and disadvantages of ceramic bricks production by the method of semi-dry pressing, using traditional technology, are considered. Urgent problem of improving the available clay rocks’ properties, depleted in clay fractions and containing large amounts of dust particles is appeared in many regions due to the shortage of high-quality clay raw materials. The used materials were clay rocks of the Novosibirsk region. Research methods were introduction of directional additives to the composition of raw mixes that affected the compressive strength, water absorption, brightness and color of the burnt shard. The research results showed the need for an individual approach to the raw materials of each field. Types of additives, contributed to reducing water absorption, eliminating crack formation, increasing strength, expanding the color range of products, were identified.
Investigation of the effects of fuel slag on the properties of gypsum mixtures
Authors: Butakova M D
Published: November 2020

The article analyzes the effect of fuel slag on the properties of a gypsum binder. An optimal composition of a gypsum binder based on an ash and slag mixture has been developed in order to minimize costs, several compositions of plaster with different aggregates have been developed, an optimal composition has been identified based on the properties obtained. Gypsum binders and materials based on them are progressive building materials due to the simplicity, efficiency and low energy intensity of production. However, gypsum binders have high water demand, and products are characterized by low water resistance, limited strength, and low frost resistance.
Methods of assessing the durability of high performance concrete
Authors: Trofimov B Ya , Kramar L Ya , Shuldyakov K V
Published: November 2020

To ensure concrete durability in reinforced concrete structures is one of the main problems of modern concrete technology. In the State Standard (GOST 31384-2017) we can find the restrictions to concrete composition depending on the class and index of operating media, but there is no information on how they affect the durability, what kind of service life of concrete and reinforced concrete structures they guarantee. This articles shows that the restrictions to concrete composition are necessary but not sufficient to ensure concrete durability especially under harsh conditions of its operation. This is due to the fact that in the national standards the role of the basic concrete strength index, which is the microstructure of hydrated phases of cement stone, is not taken into consideration. The cement gel formed by calcium hydrocilicates and being the densest and strongest component of the structure, determines the concrete durability provided it is stable in specific environmental operating conditions. The proposed methods of assessing the stability of concrete microstructure make it possible to optimize technological parameters of production of reinforced concrete structures of high performance and durability.
The effect of a plasticizer based on polymethylene naphthalene sulfonic acids on the structure of a magnesian stone
Authors: Averina G F , Koshelev V A , Kramar L Y
Published: November 2020

The article presents the results of a study devoted to identifying the effect of a plasticizer based on polymethylene naphthalene sulfonic acids on the structure of a magnesian stone. It is known that the strength characteristics of magnesian stone samples modified with various amounts of such additive have different strength, provided that the water/cement ratio does not change. This study allows to identify the relationship between strength characteristics and structural features of magnesia stone modified by additive, as well as the effect on the dosage of this additive on the formation of the main structural minerals of magnesia stone. Study of the samples structure, the electron-scanning microscopy method and an X-ray microanalyzer were used. According to the results of the study, it was found that the presence and amount of a plasticizer based on polymethylene naphthalene sulfonic acids promotes the various formation and distribution of the main structural phases of magnesia stone. The optimal amount of additive allows to get the most amorphized structure of magnesium pentaoxyhydrochloride, providing it with the highest strength characteristics.
The use of metallurgy waste in the roads sustainability improving
Authors: Pimenov A , Barakhtenova L , Pribylov V
Published: November 2020

The purpose our scientific work is to develop recycling techniques metallurgical slag (MS) of the Kemerovo regions’ industrial enterprises in the Russian Federation in order to increase the roads sustainability. The research methodology was based on our developed technological schemes of MS recycling, which justified the need for a consistent transformation of their properties through a series of mechanical and physic-chemical effects. Express method of selecting mixtures composition for the bases of pavements from various MS fractions was used for the rapid selection of the densest asphalt mixtures composition. The obtained results indicate that the use of steelmaking slag in the composition of asphalt mixtures determines the possibility of improving their operational properties. This circumstance determines the possibility of using such mixtures for pavements repair, increasing the life of existing roads, as well as the construction of new ones. This means that metallurgical slag can become an important reserve for natural building materials in the process of preparing and laying asphalt mixes on city streets and highways of various classes and categories. Their cost and reserves will make it possible to build pavements resistant to dynamic loads and alternating temperatures with relatively low material costs.
Process control system software (in the context of autoclaved aerated concrete production)
Authors: Leontev S V , Shamanov V A
Published: November 2020

Building industry production shall be considered as a complicated hierarchy system, whose conditions are related to multiple factors. To manage such complicated systems, mathematical modeling methods shall be used to organize awareness of manufacturing parameters, to increase the effectiveness of decisions being made by personnel on different positions and within the process, also to develop construction materials production management systems. In turn, synthesis questions with regard to the management of this process are largely resulted from the deficiency in mathematical model concerned, suitable for practice. Outputs of work on the process control system software for autoclaved concrete production are presents in the article. A justification for the most efficient process control stage is given. A control algorithm is developed for the selected process stage, based on a mathematical model of the end product quality as a function of raw materials demand prepared by authors.
Composite materials in building structures using 3D technology
Authors: Muruzina E V , Zonina S V
Published: November 2020

In recent years, composite materials have occupied a significant place among building materials. Among them can be distinguished glass and carbon fiber, which are largely distributed in construction. They are widely used in the reconstruction of concrete structures, for the production of structural products-as a substitute for some metal and stone structures, which is caused, first of all, by their significant mechanical properties and lightness. However, their fragility and relative high cost is an obstacle to the widespread use of this material. The introduction of 3D-technologies allows to reduce the cost of manufacturing building structures from composite materials, to increase their quality and manufacturability. 3D technologies also simplify the erection process and enable the implementation of complex architectural solutions.
Optimal dry mixes simulating
Authors: Ilina L V , Mukhina I N , Tulyaganov A K
Published: November 2020

When applying mortar mixes in thin layers on porous substrates, moisture is released from the mortar mix. As a result, such operational characteristics of the solution as bending strength, compressive strength, adhesion strength and crack resistance can be reduced. The introduction of modifying additives, such as: dispersed mineral additive, powder polymers and fibers, allows providing these indicators at the required level. In order to simulate the composition of the dry mix with modifying additives, multivariate design of the experiment was carried out, regression equations were obtained, statistical analysis of the proposed equations was carried out, which confirmed their significance. The verified model showed a high degree of correspondence between the values calculated by the regression equations and experimental data. The procedure of regression equations maximizing made it possible to determine the optimal composition of dry construction mixes depending on their functional purpose, hardening conditions and operation.
Sol-gel technology for the production of high-strength refractory materials based on binders
Authors: Pogorelov S N , Semenyak G S , Kolmogorova A O
Published: November 2020

The technology of production of die tooling based on high-alumina cement, used for the manufacture of aluminum alloys, transforming into a plastic state at high temperatures, is considered. This technology is based on the sol-gel method, characterized in that the formation of a crystalline high-strength structure for die tools based on high-alumina cement occurs cyclically with stage exposure at certain temperatures. First, a sol is formed-a free dispersed system, then a gel structure-a bound dispersed system. The final structure is crystalline, high strength with a compressive strength of up to 180-190 MPa. A distinctive feature is the possibility of destruction of the form after the manufacture of products. This is necessary because the manufactured products have a developed geometric shape and the product can not be obtained from the mold by ordinary removing the formwork.
Impulse excitation technique and its application for identification of material damping: an overview
Authors: Popov I I , Shitikova M V
Published: November 2020

The recent work presents an overview of the papers devoted to the application of Impulse Excitation Technique (IET) for the measurement of internal friction in different materials. IET is an advanced method to measure such materials’ characteristics as Dynamic Young’s and Share Moduli, Dynamic Poisson’s Ratio, Damping, to investigate the deformation behavior, softening phenomena and relaxation mechanisms and phase transformations in different materials. The experimental studies can be performed at both, room and high temperatures. Due to its simplicity, low cost, high accuracy and reproducibility it may take the leading position among the other non-destructive testing methods and techniques.
Comparative analysis of thermofluctuation constants of polyvinyl chloride plates obtained in various ways
Authors: Erofeev A V , Gorokhov T I , Drannikov R N
Published: November 2020

To reliably predict efficiency of solids, it is necessary to know the values of their thermofluctuation constants, which are determined by experimentally obtained data using graphical, graphoanalytical, and mathematical methods. Using the same initial data, the thermal fluctuation constants were determined by different methods. The graphical method is presented by calculation using graphs built on graph paper. The graphic-analytical method uses MS Excel. The mathematical method operates directly with equations instead of a graphical representation. It is shown that the chosen method of obtaining the constants has a significant effect on the final result. It is recommended to use a mathematical method when determining the thermal fluctuation constants.
Algorithm formulation for adjusting the estimated composition of concrete mixture taking into account relevant properties of the raw materials
Authors: Koshelev V A , Kovaleva O I , Averina G F
Published: November 2020

This article deals with the research dedicated to the formulation and testing algorithm of water amount adjustment tempering while producing concrete mixtures depending on raw material characteristics. The algorithm is intended for an automated quality control system of concrete mixtures of raw components, providing continuous data collection in real time. The article provides the necessity of automatic quality control implementation and adjusting the calculated compositions of concrete mixtures based on them. There is the discussion of factors discouraging the formulation and implementation of the given systems at the existing production of reinforced concrete products. There were formulated the ways of solving the problems, the scientific significance of the proposed projects was proved. There was revealed the main parameter of the concrete mixture, which provides the concrete quality obtained on its basis and factors influencing it associated with the physicochemical characteristics of raw materials are shown.
Development of a simulation model for the supply of spare parts for heating equipment
Authors: Lvovich I Ya , Preobrazhenskiy A P , Choporov O N
Published: November 2020

The problems associated with the supply of spare parts for heating equipment are considered. The main stages of development of a simulation model that allows you to simulate the incoming flow of applications for different types of parts for heating equipment are presented. The analysis of the time series of the supply of parts for heating equipment. Then there are opportunities for modeling autocorrelated flows by ordering for spare parts that have a certain relationship between each other according to the items of the item. Cross-correlation and autocorrelation functions of time series were considered, and it was revealed that these functions are not similar to each other.
Estimation of concrete durability using kinetic characteristics of its destruction
Authors: Popov V P , Popov D V , Davidenko A Yu
Published: November 2020

The article deals with the research results of concrete destruction processes by different types of external impact. The materials were obtained by the Samara research school of architecture and construction academy. The paper analyzes the process of concrete destruction and determines its main flow stages, depending on the amount of released energy of crack formation. Initial parameters of concrete structure are proposed, including: surface energy, modulus of elasticity and Poisson’s coefficient. The authors paid special attention to kinetic characteristics including tendency of concrete crack formation and crack formation intensity. The combination of kinetic characteristics is given as a criterion for concrete durability assessment. Quantitative dependence of kinetic characteristics on moisture and porosity is confirmed.
A ‘Building material science glossary’ mobile application for Chinese international students
Authors: Pogorelov S N , Bagdueva A V , Kolmogorova A O
Published: November 2020

Chinese international students encounter a variety of difficulties in their education at Russian universities. Overcoming the language barrier and adjusting to new social and learning environment are thought to be the major factors for successful training abroad. However, there is also one serious challenge that Chinese students face. Professional disciplines, in particular technical ones, are characterized by a high concentration of terms. Knowledge of specialized technical words has a strong impact on the academic development of the students. Greater vocabulary size is a main component for understanding written learning materials and for effective oral interacting with faculty members. However, just few Chinese-speaking students demonstrate a sufficient level of competence in technical Russian. In this regard, the paper raises the issue of developing language proficiency under a course in construction. On the example of building material science the authors consider compiling a bilingual glossary designed as a mobile application. Such a ‘mobile’ glossary can help Chinese international students, whose major is construction, to successfully gain subject knowledge.
Study of natural self-healing of materials based on inorganic binders
Authors: Chernykh T N , Bondarenko S A , Zimich V V
Published: November 2020

The study of natural self-healing of materials based on inorganic binders has been carried out. The age of the study was one month after loading with cracking. Microscopic analysis of samples with cracks based on Portland cement, oxychloride cement and gypsum showed that all studied materials are capable of filling cracks on their own. The filler, such as calcium carbonate or gypsum dihydrate, can have a sufficiently high strength so that a selfhealing effect is present. A filling agent such as magnesium hydroxide cannot have strength, and then only the crack is filled without restoring strength. Filling of cracks at the age of up to one month is insignificant and does not exceed 0.5 microns. This is not enough to fill large cracks. For modern building structures, natural self-healing is ineffective. This requires the use of artificial methods of self-healing in modern building structures.
Calculation of the circular plates’ stability in stresses
Authors: Tyukalov Yu Ya
Published: November 2020

The method is proposed for solving the plates stability problems by the finite element method based on piecewise constant approximations of moments. The solution was obtained on the basis of the principles of minimum additional energy and the possible displacements. To ensure the moment fields equilibrium, the equilibrium algebraic equations of grid nodes are compiled using the possible displacements principle. Such equilibrium equations are written as a system of linear homogeneous algebraic equations. Using the Lagrange multipliers method the equilibrium algebraic equations are including to the functional. The proposed method ensures the critical stress convergence to the exact value from below, which provides reserve of the plate stability.
Methodology of calculating the moisture content of soil reserves during the construction of an earth bed
Authors: Aleksikov S V , Leskin A I , Gofman D I
Published: November 2020

The authors propose a methodology for calculating the moisture content of the ground reserves based on the introduction of a moisture factor of the construction area, which is the ratio of annual amounts of atmospheric precipitation to the maximum possible evaporation for reasonable planning of organizational and technological measures for the construction of an earth bed. The proposed technique makes it possible to determine the design moisture of any soil type in the reserve according to the data of observations of precipitation and air temperature of the region, where works are performed. The dependencies, obtained by the authors, have a theoretical justification, a close correlation connection, are provided with materials necessary for mass calculations, all parameters are physically clear, which allows to use them for long-term prediction. There can be no malformations of water-thermal balance of soil of the earth bed, when calculating according to the proposed formulas.
Improving calculating theory of multiple-cavity reinforced concrete floor panels
Authors: Vasilyev A S , Plehanova E A , Xiaolong Bai
Published: November 2020

It is a known fact that core slabs are introduced as I-shaped beams (T-beams) to simplify calculations and are considered according to the beam theory. However, such a view may cause erroneous calculation results. This is particularly evident when calculating the second group of limit states. The aim of this survey is to examine the influence of the cross current representation of core slabs for samples of various length by defining the impact of these factors (the shape of the cross-section and length) on the bearing and nonrigid capacity as well as a cracking load. The paper makes the calculating theory of reinforced concrete framing clear, in particular, core slabs according to the limit states. The author dwells upon samples of slabs of various lengths with a natural cross-sectional shape in comparison with I-shaped samples of similar length. The author should emphasize that it is assumed both in analytical calculations and in software based on FE analysis in order to save time and computing resources. The author performs a computational investigation of core slabs in a nonlinear setting with forming a plastic centroid in the middle of a slab in the study. It is found out that the slab length affects the calculation results of the considered shapes. The shorter the length, the clearer cut the deviation in the load deflection plots.
Mixed finite element formulation based on the discontinuous stress approximation
Authors: Lukashevich A A , Lukashevich N K , Kobelev E A
Published: November 2020

The paper is devoted to the development of the mixed form of finite element method for the calculation of constructions and structures. We consider the approach based on the approximation of discontinuous stress fields and the use of the penalty function method to satisfy the equilibrium equations. It is shown that the continuity of both normal and tangential stresses only on the adjacent sides of the finite elements contributes to the expansion of the class of statically admissible stress fields. At the same time, the consistent approximation is provided, both of the main part of the functional of additional energy, and its penalty part. Using the given approach, solutions of some problems were obtained and analyzed, in particular, the calculation of the cantilever beam-wall. The results obtained were compared with the decisions on the FEM in displacements and stresses, as well as with the exact solutions. It is shown that solutions based on the approximation of discontinuous stress fields in mixed form FEM converge to exact values from below and are more flexible in comparison with the solutions obtained by FEM in displacements. In addition, the accuracy of determining stresses is higher here.
Optimizing the centrally compressed step-variable stiffness rods
Authors: Grebeniuk G , Lukin E , Nagaitseva E
Published: November 2020

The article deals with the optimization parameters of centrally compressed step-variable stiffness rods, with the material that is able to work both within and out of proportionality. The following algorithms are developed: the maximization algorithm of loading critical parameter at the given volume of the rod material, and the minimization algorithm of the rod material volume observing the restrictions on durability and stability, taking into account the own weight of the rod. The analysis of the optimization results is carried out and the recommendations on calculation and rod design are offered.
Modeling of the complex “Ground Base-Foundation-Construction-External Influences” taking into account the cyclic technogenic vibrational loads
Authors: Grecheneva A V , Dorofeev N V , Pankina E S
Published: November 2020

The article is devoted to the development of a mathematical model of the complex “ ground base-foundation-construction-external influences” taking into account the cyclic technogenic vibrational loads. The mathematical model is used in automated systems of geotechnical monitoring. The coefficients for a qualitative separation of the types of vibrational technological impact and its quantitative presentation are introduced into the model. These coefficients provide the implementation of the criteria for safe and efficient operation of the foundation and the structure as a whole. At the computer modeling, the dependence of the strength parameters in the complex “ground base-foundation-construction-external influences” was evaluated. It is established that the calculation using the developed mathematical model allows increasing the sensitivity to early detection of a decrease in the strength characteristics of the foundation structure by an average of 24%.
Economical reinforced concrete overpass. Graphical method of calculation
Authors: Makarov A V , Kalinovsky S A
Published: November 2020

The article considers the issue of designing cost-effective underpasses on the roads. With the wide spread of multi-level transport interchanges, the relevance of this issue is constantly increasing. Currently, mainly designed two and three-span girder viaducts (and most three-span), therefore, in the framework of this research, a comparative analysis of two-span and three-span overpass from the point of view of economy of their construction. It is known that the economic efficiency of bridge structures depends significantly on the size of the cross sections of their structural elements, which in turn depend on the internal forces arising in them from the impact of the entire complex of operating loads. As a result of calculations of internal forces in continuous beams, which are structural elements of overpasses, a graphical method for determining bending moments in two-span continuous beams is proposed, which has sufficient accuracy from an engineering point of view on the one hand and allows speeding up the design process on the other hand. In the process of developing this method, a graph of changes in the bending moments in the main beams of span structures of bridge structures is drawn up depending on the ratio of permanent and temporary loads acting on them.
Experimental research methodology for the deformation of RC frame under instantaneous loss of column
Authors: Savin S Yu , Kolchunov V I , Korenkov P A
Published: November 2020

In recent years, numerous experimental and especially numerical studies have been conducted in order to study the mechanisms of the resistance of reinforced concrete building frames to progressive collapse during the instantaneous removal of one of the columns. Analysis of these researches shows that almost all study deals with strength performance of RC structural elements under quasi static or instantaneous loss of column. At the same time, a number of numerical and analytical studies of the progressive collapse behaviour of steel moment frames as well as fragments of RC moment frames indicates that loss of bearing capacity of structures can be associated with buckling behaviour. Therefore, using the theory of functional similarity, a physical model of the reinforced concrete frame of a multi-storey building and a methodology for experimental studies of the buckling and fracture of this structural system under instantaneous loss of the corner column are proposed.
X-ray limited-angle tomography of cracks
Authors: Likhachev N A
Published: November 2020

The aim of this work is to obtain estimates of the accuracy of the x-ray limited-angle tomography method for determining the shape and size of internal cracks in large-sized reinforced concrete structures. A fan-beam registration scheme with a source moving along a circular arc is considered. For reconstruction, we use the fan-beam transform inversion formula and the algebraic method ART. By means of numerical simulation, the dependences of errors of the first and second kind on the mutual orientation of the central beam and the direction of the crack, the angular size of the source trajectory and the noise level are obtained.
Geometrically nonlinear buckling analysis of truss under mechanical and thermal load based on mixed finite element formulation
Authors: Quyen Vu Thi Bich , Tien Dao Ngoc , Lan Huong Nguyen Thi
Published: November 2020

This paper is concerned with the numerical method for the geometrically nonlinear buckling analysis of truss under mechanical load and thermal load due to constant temperature change. The solution of a geometrically nonlinear problem of the system under thermal load based on a displacement-based finite formulation requires the implementation of thermal deformation constraint depending on the incremental element length. The additional constraint of thermal expansion considerably increases the difficulty in finite element formulation and solving method of the nonlinear buckling problem. This research proposes a novel approach to formulate the nonlinear buckling problem of truss under thermal load based on mixed finite formulation. The mixed balanced equation of thermal loading truss considering large displacement is formulated using the principle of virtual work. Based on the formulated equation, the research develops an incremental-iterative algorithm and calculation program for solving the nonlinear buckling problem of thermal loading truss using the arc length technique. The numerical test is presented to investigate the effect of thermal load to buckling behaviour of plan truss.
Finite element analysis of plane frame systems with different models of semi-rigid connections
Authors: Van Tran Thi Thuy , Tung Ngo Dinh , Trung Kien Nguyen
Published: November 2020

Today, in the current Vietnamese design standards for semi-precast reinforced concrete and steel frame structural systems, the connections of main elements such as beams and columns are commonly considered as either perfectly hinged or rigidly fixed. This assumption is adopted because of the simplicity in design and analysis process but it is not consistent with actual behaviour in practice of structural systems. The connections between columns and beams have partial restraint depending on the type of used connection. The analysis of structural system with consideration of the effect of this restraint would result more exactly and economically. However, it is also more time required because of complexity of analysis process with consideration of flexibility of connections in the case of lack of suitable calculation method. The paper presents the analysis of plane frame systems with different of models of semi-rigid connections using finite element method. The analysis process was implemented by MathCad programming software and the results of this study will obtained by conducting of numerical examples. From there the conclusions and recommendation of calculation and design for steel and semi-precast frame systems will be proposed.
Internal resonances in nonlinear fractionally damped plates of the Uflyand-Mindlin type
Authors: Shitikova M V , Osipova E I , Rossikhina E Y
Published: November 2020

In the present paper, the non-linear free vibrations of fractionally damped plates are investigated for the case when its equations of motion involve the rotary inertia and shear deformations via five coupled nonlinear differential equations in terms of three mutually orthogonal displacements and two angles of rotation. The damping features of the surrounding medium are described by the fractional detivative Kelvin-Voigt model. The procedure resulting in decoupling linear parts of governing equations has been proposed, what allows one to utulyze effectively the fractional derivative expansion method for solving the non-linear equations of motion. The occurrence of the internal or combinational resonances has been revealed and classified for plates of the Uflyand-Mindlin type.
Automatic assembly of wind load from BIM-model
Authors: Degtyarev N , Pridvizhkin S , Salnikov V
Published: November 2020

In recent years many Russian construction companies have started using technologies of building information modelling (hereinafter – BIM). It’s a global trend aimed at maximum automation and acceleration of a design process and documentation approval. This article shows main advantages of the BIM approach, discusses the possibility of expanding “the space of benefits” by using digital building models for wind load simulation (automatization of this process). Currently, applied methods of wind impact analysis based on which automation is possible are described. Potential application scenarios, describing the advantages of automatic wind load assembly, are listed. Also, possible approach to the analysis of loads in process of BIM-design is shown.
Bar structures calculation by the method of discrete elements with generalized unknowns in aggressive environments
Authors: Dushko O V , Voronkova G V , Rekunov S S
Published: November 2020

The article considers the application of the method of discrete elements with generalized unknowns for calculating rod systems located in an aggressive environment. The object of research was a spatial rod truss. The basic formulas for determining the reactions of bonds at unit displacements are shown. The equation of displacements for an arbitrary node is derived. The system of equations was solved in partial finite differences. Reactions from external loads were represented as trigonometric series. An algorithm for calculating a statically indeterminate spatial truss by the method of discrete elements with generalized unknowns under the action of an aggressive environment is given. As a result of the calculation, the values of node point movements are obtained.
Search for plastics with piezo optic properties
Authors: Aseyev M A , Tabanykhov K A , Tabanykhova M V
Published: November 2020

The work is devoted to the search for plastics used in 3D printing, which have pronounced piezo optic properties. A review of the works devoted to the study of various characteristics of plastics is performed. It is established that there is currently no data on the piezoelectric properties of consumables for 3D printing. The various brands of plastics widely represented on the market are analyzed. Between them, those that transmit light well were selected. Experimental studies of widely available transparent plastics were performed. The photoelasticity method is used in the work. Several grades of plastics with birefringence have been identified. In the future, it is planned to use these materials for printing models of nodes of spatial structures on a 3D printer in order to obtain stress fields in them.
Multilayer facade panel structure analysis
Authors: Sharovarova E P , Alekhin V N , Skachkov A Y
Published: November 2020

At present, the problem of energy saving is urgent in the world community. The construction and operation of buildings accounts for over 40% of all materials and energy. The problem of energy saving is an integral part of building design. The world experience shows that one of the most effective ways to reduce specific energy consumption in buildings is additional thermal insulation of enclosing structures. The research of different types of modern facade structures of buildings has led to the development of a new type of enclosing structure-a multilayer facade panel (MFP). This article presents the description of MFP construction and the results of the finite element analysis (FEA) with ANSYS solver.
Risk management in monolithic construction
Authors: Topchiy D , Bolotova A
Published: November 2020

Current statistics with regard to the impact of various random factors on the condition of structural units, building elements and structures clearly indicate a number of problems associated with construction safety in general. Prevention of typical frequent accidents requires that methodological recommendations are in place to control or mitigate risks. Risk management in construction operations is to a large extent focused on the relative safety concept. The main tasks are integrated risk assessment, minimization, identification, and analysis, as well as the development and substantiation of managerial solutions. A vital issue reviewed herein is the problem of insufficient use of the risk management system by building companies. This article identifies the main directions of assessing risk events and the degree of damage in construction projects. Analytical research findings have led to a conclusion on the need for development of risk assessment methods to be applied in the organization of construction operations.
Agreements of participation in shared construction: relationship of legal, tax and accounting aspects
Authors: Guzikova L A , Neelova N V
Published: November 2020

The article discusses theoretical and practical problems associated with the legal status, accounting and taxation of agreements of participation in shared construction (APSC). Contradictions between the economic content of operations under APSC and its legal form revealed. The consequences of the transition to the use of escrow accounts assessed. The expediency of wider application IFRS provisions and requirements in the accounting of operations under APSC substantiated. It’s proved that wider application of IFRS will allow increasing the reliability of information, avoiding data manipulation and improving the comparability of different companies’ reporting. The results of the study may be useful to heads, managers and accountants of construction organizations, as well as researchers involved in the issues of financing construction.
Creation of integrated interaction monitoring in the construction companies management
Authors: Pesotskaya E , Selyutina L , Trushkovskaya E
Published: November 2020

The relevant theoretical and practical issues of the management system development in construction companies, adapted under modern non-equilibrium conditions of management are considered in the article. The methodical provisions on the use of the interaction concept in the management of the construction business organization adaptation are formulated in the article. Considering the obtained research results, the author’s approach to creation in the construction companies of integrated interaction monitoring based on a principle of synthesis of strategy and tactics is stated. The special attention is given to a problem of the rational organization of the information environment at the company, excluding occurrence of “barriers” for passage of the information concerning problems of strategic and tactical adaptation, and concrete methodical techniques on their overcoming are offered.
The processes of the organization and construction management in the activities of small and medium businesses
Authors: Matveeva M V
Published: November 2020

Small and medium-sized enterprises (hereinafter referred to as SMEs) in developed countries constitute the most important sector of national economies. While large enterprises determine the level of scientific, technical and production potential of a country, SMEs, being the most popular form of business life, provide socio-economic stability of development construction industry. The article considers the main indicators that characterize the development of the SME sector in construction sector in the Russian Federation. According to the analysis, the SME sector is characterized by increased dynamism, flexibility, innovation activity, the ability to quickly create new industries and generate new jobs. The article highlights the main disadvantages of the business environment and restrictions that arise in the way of small business development in construction, analyzes the existing measures of state support for SMEs and describes their impact on the main indicators of the country’s economy. & At the same time, it is determined that it is necessary not only to assist in the formation of a new generation of entrepreneurs, but also to create conditions for the development of small and medium-sized enterprises that have the potential to grow and turn such companies into centers of economic renewal construction industry in the country.
Management of deconstruction of construction objects
Authors: Bukunova O , Bukunov A
Published: November 2020

A change in any design variable can affect the environment during all relevant stages of the building life cycle. Because of competition, design and construction companies have become very interested in developing sustainable construction due to the modernization of resource potential optimization and management. The production chain has been built as part of an assessment of the life cycle of a construction project to address the challenges of sustainable construction. The possibilities of using information modeling for the planning and design of building deconstruction are analyzed. A deconstruction control method using information modeling has been developed, which implements control based on a simple and advanced feedback loop.
Pulse control of temperature mode of buildings with elevator system connection heating
Authors: Panferov S V , Panferov V I
Published: November 2020

The problem of energy saving when heating buildings is considered. The problem of weather regulation of heating systems with an elevator connection has been solved, including during the “cut-off” of the temperature regime. An algorithm for impulse control and the composition of automation systems for its implementation have been developed. The duty cycle of the control pulses is determined by the results of measuring either the temperature of the heating system and its flow rate, or the temperature of the coolant at the inlet of the heating system and its flow rate in it. The repetition period of control pulses is selected based on the required quality of regulation in the steady state. This takes into account both the heat-shielding properties of the heated buildings and the characteristics of their heating systems. A qualitative analysis of the dependences of the duty cycle and the repetition period of control pulses on influencing factors has been carried out. At the same time, the approach to solving the problem used in the work, in contrast to the previously used, is more “transparent” and simpler.