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  • Global Trends in Machine Learning Technologies for Reinforced Concrete Structures

    The article provides a review and systematisation of works devoted to the application of machine learning for solving problems of research, calculation and design of reinforced concrete structures. It considers the aspects, which are relevant today, related to calculation, design, as well as assessment of the technical condition of objects with the help of various approaches that implement machine learning schemes, including deep learning, ensemble algorithms. It is shown that nowadays in the world construction science this area is rapidly developing and improving. Thus machine learning algorithms solve problems of prediction of design parameters, problems of identification of these or those parameters, defects, damages on the basis of classification algorithms and others. The materials presented in the article will allow specialists to choose the subject area of research more precisely and determine the directions of adaptation and improvement of their own developments in the field of machine learning.

    Keywords: machine learning, reinforced concrete structures, regression equations, identification, approximation, artificial intelligence

  • Assessment of the condition of culverted corrugated metal pipes

    The article considers the causes of the formation of defects to be evaluated. The methods of obtaining information about the condition of metal corrugated pipes are presented. The main defects arising during the operation of metal corrugated pipes are shown. The most effective methods of assessing the condition of metal corrugated pipes have been determined.

    Keywords: corrugated metal pipes, wear, durability, defects, factors, evaluation

  • Comparative analysis of design solutions for school lighting with lighting devices from different russian manufacturers

    A comparative analysis of the lighting conditions of school premises was carried out based on design solutions for lighting devices from three Russian lamp manufacturers. All projects were carried out using lighting devices based on recommendations to manufacturers to use their range of lamps to illuminate various school premises. The design was carried out using the DIALux program. Each of the three manufacturers is widely known to specialists and has established itself as a reliable manufacturer of domestic lighting products, ready to offer a full range of lamps for various school premises. A technical and economic comparison of the total present costs for all lighting installations (using the example of one entire school) made it possible to conduct a comparative analysis and determine the most profitable options. An analysis of the current state of the Russian market of lighting devices recommended by manufacturers for classroom lighting has been carried out, their characteristics have been reviewed, and their compliance with current energy efficiency requirements has been assessed. Conclusions and forecasts have been made for the further development of lighting equipment with LEDs for lighting classrooms, based on the need to constantly improve the modern range of lighting devices in terms of their energy efficiency and competitiveness.

    Keywords: technical and economic comparison, levelized cost method, comparative analysis, school lighting, lighting device, lighting modeling, energy efficiency

  • Application of information modeling technologies in "green" construction: an overview of foreign experience

    The article provides a brief overview of foreign experience in the application of information modeling technologies (BIM) in "green" construction. The work carried out a scientometric assessment of publications on the topic of BIM in "green" construction. As a result of the review, it was found that BIM has recently been increasingly used in the field of "green" construction, forming a new stage of resource efficiency and minimizing the negative impact on the environment.

    Keywords: information modeling technologies, "green" construction, sustainable development, building life cycle, resource management, energy efficiency and environmental friendliness

  • A nonlinear finite element model for calculating the shear force of I-beams made of ultra-high-strength concrete

    The development of methods for calculating structures made of ultra high-performance steel fiber-reinforced concrete (UHPC) in terms of strength and deformations is an important step towards the introduction of this innovative material into the practice of design and construction. This paper presents the results of finite element modeling of the operation of UHPC I-beam in the area of action of shear forces. The SMM model integrated in the OpenSees framework application is used for the walls of beams under conditions of flat stress. The authors have added new classes of materials that implement the averaged deformation laws of UHPC (with and without fiber) and the reinforcement placed in it. The calculations showed good convergence with the authors' own test results of the UHPC I-beams, as well as with the results of experiments by other researchers.

    Keywords: shear strength, shear force, ultra high-performance steel fiber-reinforced concrete, I-shaped beams, OpenSees

  • Structure of flat rod systems

    The choice of the method of force calculation of building structures is preceded by an analysis of the static determinacy and immutability of the rod system using structural formulas, while for different types of structures - for beams, trusses, frames, arches, etc. - sources offer different formulas. It is shown that for the structural analysis of all rod systems it is sufficient to determine the degree of structure anomaly using the formula of P.L. Chebyshev. The development of the linear-monad theory of structure makes it possible to formalize the dependence of the number of rods and hinges on the number of external and internal contours in the synthesis of both normal and anomalous structures

    Keywords: beam, truss, frame, arch, structure, analysis, synthesis, immutability, definability, degree of anomaly, rods, system, contour, monad, hinge

  • Application of graph theory for subjective evaluation of residential planning solution

    Providing the population with comfortable housing has always been a pressing issue. However, there are very few formalized criteria for this, apart from the regulation of minimum floor areas. In this context, the article deals with the problem of evaluating the efficiency of residential space design solutions in terms of their logistical comfort. For this purpose, a method is proposed that uses the apparatus of graph theory and allows to calculate the time cost of an "idle" move for a representative of a given social group in relation to the evaluated design solution. An idle move is a user's movement between characteristic functional zones of the layout. A special matrix is used to model the links between these zones, the construction of which is similar to that of the incident matrix in undirected graphs. As an example of the applicability of the proposed approach, several variants of layouts of one-room, two-room and three-room flats are considered. The comparison of the obtained results for different types of layouts, including those that existed 15-20 years ago and modern ones, indicates a tendency to increase the logistic comfort of modern layouts.

    Keywords: planning solution, logistic comfort, idling, graph theory

  • Study of building envelope thermal inertia

    Authors considered the thermal inertial properties of some building envelope constructions which included the changes of internal surface layer materials. Researchers described the thermal and physical characteristics of 6 building surface layer materials. It has been determinate the radiant temperature of building envelope inside surface with changes of wall construction after 225 hours cooling process and initial temperature equal to +23 оС. Authors defined the cooling time of building envelope inside surface to 0 оС at different types of surface layer materials. Numerical experiment was done with modern program complex “Stf”. Modeling process was completed in program which was realized with finite difference method and constant heat transfer coefficient. There are new experimental results which were determinate during the research and realizing the mathematical model of non-stationary element’s cooling process. Results could be interested for researchers of thermal phenomena in building envelopes and designers of microclimate engineering systems in buildings and structures.

    Keywords: air temperature, radiation temperature, stationary regime, non- stationary regime, building envelope, emergency regime, thermal inertia, inside surface layer, program, building materials

  • Study of the influence of water of the Gulf of Finland on the chemical composition and strength of wood during long-term use

    The article shows the importance of analyzing the state of strength properties of old wood during restoration work and monitoring the state of the structure. In particular, the physical and mechanical properties of wood during long-term use in an aquatic environment are analyzed. Changes in the chemical composition of wood as a result of use in the water of the Gulf of Finland are determined. Using the example of logs of the crib foundation of the Kronshlot fort, it is described how a change in the chemical composition of the material affects its strength properties.

    Keywords: Mechanical properties of wood, long-term strength, chemical composition of wood, water-soluble extractive substances

  • Adhesion of reinforcing bars to the alkaline matrix of slag-alkali concretes

    Slag-alkali binder (SAB) is obtained by polymerization of granulated blast-furnace slag (aluminosilicate component) ground in a ball mill with an alkali activator, resulting in an environmentally friendly hydraulic polymer binder. Slag-alkali concrete (SAB) based on SAB has become an alternative to traditional concrete based on portland cement (PTC). Reinforcement bars in combination with SAB make it possible to obtain concrete structures with high adhesion properties to reinforcement compared to concrete based on portland cement. However, due to differences in the production process of SAB, there are obvious differences in technical properties, including adhesion characteristics. However, proper standardization is needed for its production and operational testing to limit contradictory results in the laboratory and on the construction site.

    Keywords: metallurgical waste, granulated slag, crushing, chemical activation, reinforcement, adhesion, strength

  • To calculate the stability of a П-shaped frame with hinged support

    The stability calculation of a П-shaped hinged frame is considered. The concept of r-like frames is introduced as frames with the same ratio r of the linear stiffnesses of the transom and the strut. It is shown that the parameter vcr , which determines the critical load on the frame, is the same for r-like frames. Approximate formulas allowing to determine the critical load parameter vcr and design lengths of compressed bars with an error not exceeding 2% are obtained.

    Keywords: flat frame, stability, critical force, reduced length coefficient, r-like frames, approximation, least squares method

  • Comparative analysis of modeling of design schemes with monolithic ribbed slab using BIM-technologies

    The article is based on modelling several variants of information diagrams of a corrugated monolithic ceiling of an industrial building. The information model has been transformed into an analytical model. The comparative analysis of all calculation models was carried out visually and in numerical aspect. The efficiency of BIM-technologies in design with the application of software complexes «Renga», «CAPFIRR-3D» and «LIRA-CAD» is also considered in the calculation and construction section. The comparative analysis of three variants of the joints of the beams and the slab of the covering was carried out. The analysis of the stress-distorted state of the calculation circuit was also performed.

    Keywords: ribbed slab, industrial building, design of buildings and structures, BIM-technologies, calculation scheme, information model, rigid insert, stress-strain state, finite element method

  • Prospects for the use of fluorescent concrete in the construction and operation of underground linear transport structures

    The article discusses issues of improving the quality and safety of pedestrian and vehicle traffic in underground linear structures. The main parameters of traffic safety in tunnel-type transport structures are considered. The scope of application of luminescent and retroreflective materials in the construction and operation of concrete and asphalt concrete pavements has been determined. Recommendations are given for the use of special luminous materials in construction practice.

    Keywords: concrete, asphalt concrete, reflective coatings, luminescent materials, traffic safety

  • Perspective directions of application of illusion in architecture

    In this article the existing principles of application of the illusion technique in architecture are considered. The classification of objects by purpose is presented, the key features of classification groups are highlighted. Examples of already existing constructed buildings with different typology are given and analyzed. The target direction of the article is based on the creation of the concept of volume (building) with the use of optical illusions to form a complex solution to clarify the overall concept of the object and achieve the effect of paradox in the viewer. The article also describes in detail the art-architectural and constructive solutions of the proposed concept with the definition of the exact location of the building in relation to the view and approach to it.

    Keywords: Illusion, architectural volume, complex solution, paradox, dematerialization, visual perception, structural element, mirrored surface, hovering effect, tilt angle, master plan organization

  • Framed steel earthquake-resistant structures comparative analysis of traditional design principles

    The article describes the main problems associated with the principles of calculation and design of building structures of buildings and structures in seismically active areas in accordance with the provisions of the regulatory document SP 14.13330.2018. The difficulties that may arise when using foreign regulatory requirements in terms of design and calculation are noted. The calculation of a flat steel multi-story frame for the main and special combination of loads and impacts is considered. The frame calculation for a special combination is performed according to SP 14.13330.2018 with and without taking into account the additional requirements of foreign design standards ASCE / SEI 7-22, ANSI / AISC 341-22. The requirements of foreign standards were not taken into account in full, but only in terms of increasing the reliability of the structure, for certain positions. The change in the parameter of the frame metal consumption for various calculation options is analyzed. Conclusions are formulated and recommendations are given on how to reduce the metal consumption when calculating for seismic impact, taking into account the increase in the reliability of building structures.

    Keywords: finite-element schemes, columns, crossbars, seismic action, steel frames, flat frames, design, limit states, material consumption, optimization, reliability, special combinations, combination factors

  • The use of carbon fiber-based FRP systems to strengthen reinforced concrete structures of buildings and structures

    The article provides an analysis of the state of the rationing issue in terms of performing the calculation justification and design of reinforcement of reinforced concrete structures using external reinforcement systems based on carbon fibers. The normative documents of the Russian Federation and foreign ones are considered, the analysis of the use of external reinforcement based on composite materials for structures of various types of work is carried out, the disadvantages of existing calculation and design methods are highlighted. In conclusion, recommendations are given on the appropriate improvement of calculation and design methods.

    Keywords: external reinforcement, carbon fiber, reinforcement, restoration

  • Evaluation of load-bearing capacity design of baskets for conditioners: analysis of results and tests

    The article presents the results of the laboratory test and finite element modeling of the facade basket design for the outdoor unit of the split system. A comparative analysis of the obtained data is performed. During the modeling, the main possible design situations were taken into account and the perilous zones were determined, in which destruction is expected. To confirm the obtained design values, a full-scale test was carried out, in which wind pressure was modeled using two horizontally applied loads. Based on the test results, it was determined that the modeling method used corresponds to reality, and the nature of destruction and maximum permissible loads were also established. Based on this, a conclusion was made about the suitability of using the facade basket design option considered in the article for the specified operating conditions.

    Keywords: finite element model, testing, load-bearing capacity, reliability, deformability, air conditioner basket, bracket, destruction

  • Methods of combinatorial search modeling to achieve sustainability indicators in the architecture of multifunctional residential complexes

    The architecture of multifunctional residential complexes (MFRC) is considered in the aspect of “resistance” to external factors and influences. There are four levels of formation of the MFRK: the level of urban planning structure; level of volumetric-spatial organization; level of functional and architectural planning structure; the level of compositional organization and search for the expressive appearance of the MFRK. At each of the identified levels, the “target” indicators of “sustainable architecture” are achieved. The process of forming the MFRC is considered as a sequence of combinatorial search stages and procedures based on modeling the geometric parameters of the visual model of the MFRC in order to get as close as possible to the “stability indicator”. Four methods of combinatorial search modeling are proposed: the method of “overlaying” planning frames; method of “tracing” the formative contour; method of “collaging” functional planning elements; a method of combining “regular grids” in the public, business and residential parts of the MFRK. To intensify combinatorial search procedures, it is proposed to use digital design technologies.

    Keywords: university complex, transit urban spaces, scenario approach, functional-thematic zones, architectural and environmental modules

  • On the issue of inspection of consoles of precast reinforced concrete columns in case of manufacturing errors

    The paper presents the results of the survey of consoles of precast reinforced concrete columns of an industrial building under construction. The consequences arising from errors during the manufacture of columns, as well as the method of calculating the console are described. The survey was carried out in order to detect the position of the reinforcement in the consoles of reinforced concrete columns. When performing a survey of the technical condition, the following tasks were set: to determine the actual condition of the supporting structures, their mating nodes at the time of the survey, to establish the actual reinforcement of the structures, to give recommendations for the restoration (strengthening) of the bearing capacity of the column consoles.

    Keywords: inspection, load-bearing capacity, concrete, column, reinforcement, strengthening

  • On the issue of surveying monolithic reinforced concrete foundations of machines with dynamic loads from increasing vibration levels of equipment

    The paper presents the results of the survey of the reinforced concrete monolithic foundation of a ball mill with central unloading. The consequences of errors made during the construction of the foundation of machines with dynamic loads, as well as the foundation monitoring methodology, are described. The survey was carried out due to an increase in the vibration level of the equipment installed on the foundation and the detection of foundation defects in the form of cracks and chips in concrete. When performing the technical condition survey, the following tasks were set: to determine the actual condition of the supporting structure at the time of the survey, to establish the physical and mechanical characteristics of the materials of the structure, to indicate the characteristics and dimensions of damage sufficient to determine the volume of repair and restoration work, to develop recommendations for further safe operation of the structure.

    Keywords: inspection, bearing capacity, foundation, dynamic load, concrete, reinforcement, strengthening

  • Modern requirements for the modernization of university campuses

    Modernization of university campuses in the context of the development of domestic higher education and science to increase the technological sovereignty of the country is one of the pressing problems of modern domestic architecture. The article examines the main factors that determine the need to modernize existing university campuses and influence its capabilities and tools. Based on the analysis of these factors, the main modern requirements for campus modernization are formulated.

    Keywords: modernization, university campus, modernization factors, modernization requirements

  • The development of the idea of architectural reserves of Spegalsky in the modern urban planning structure of Pskov

    The article analyzes the idea of architectural reserves proposed by Pskov architect and restorer Yu.P. Spegalsky in the middle of the XX century. The Pskov restorer proposed to allocate separate sections of the city center with ancient monuments on their territory as the basis for its development as an open-air museum. The plan was not implemented, but later this theory was used as the basis for successfully implemented modern restoration and architectural projects aimed at developing the urban environment of Pskov. The options for continuing the development of the idea in the near future are considered on the example of a complex formed by ancient defensive structures and a monument of constructivist architecture.

    Keywords: Y.P. Spegalsky, architecture of ancient Pskov, creativity of A.A. Olya, restoration in Pskov, Mstislavskaya Tower.

  • Simulation of the design activity diversification of innovative enterprise

    The article discusses the features and prospects of implementing distributed management of critical urban infrastructure facilities based on the principles of autonomy. Based on the analysis, the main technologies, directions of development and features of energy transfer in an urban environment are highlighted, contributing to the introduction of distributed management of urban infrastructure facilities. The study focuses on the analysis of the distributed structure of integrated security of critical urban infrastructure facilities and the development of general principles of distributed management of critical infrastructure facilities using the «Autonomous Building» technology. t is shown that the reliable and safe functioning of critical infrastructure facilities in the city is ensured through the synthesis of special technical systems for complex protection of the facility from major security threats based on the combined use of elements of life support and safety systems. At the same time, technical life support systems for autonomous objects of critical infrastructure of the city are built on the basis of the combined use of autonomous energy sources, including non-renewable energy sources, on the principles of joint operation of electric and static power converters, storage, frequency regulation and energy conversion, and technical safety systems of autonomous objects are built using combined optical and electronic means event detection and recognition with the ability to control the full spectrum of electromagnetic radiation.

    Keywords: distributed management, technology, energy, energy transfer, urban infrastructure, critical facility, electrification, decentralization, automation, autonomy

  • Investigation of the dependences of the critical state of cylindrical mesh shells

    The use of a solid analog and the involvement of an appropriate theory of stability made it possible to perform mathematical modeling and determine the parameters of the critical state of cylindrical mesh shells depending on the geometric characteristics and the number of half-waves of the shape of the loss of stability. The values of the critical load of cylindrical mesh shells are determined taking into account geometric and force factors. According to the results of calculations, the patterns of changes in the number of half-waves of the form of loss of stability and obtaining the minimum value of the critical load under the condition of maximum approximation of flexural and membrane stiffness are revealed and analyzed. A numerical example is shown in which the values of critical load and stiffness are determined, taking into account possible forms of loss of stability. The patterns of changes in these indicators for a given number of half-waves are established and analyzed.

    Keywords: cylindrical mesh shells, mathematical modeling, critical load, stability, stiffness, number of half-waves

  • Development of architectural and planning techniques in penitentiary architecture

    This study will examine the historical formation of the architecture of places of detention. The author gives space to the volumetric and planning transformation of prisons, examines the history of their emergence in stages and reveals the connection of these changes with the changes in the state and society as a whole. The study deals with the issues of restraint of freedom from inside and outside the penitentiary institutions, and partially touches upon the connection between fortification and penitentiary institutions in the sense of the continuity of the urban, architectural and landscape planning techniques of defence used. The study also presents examples of modern layouts; the types of layouts and the architectural means and techniques used in them to create a safe and comfortable environment are summarised in a table as material for analysis. In addition, as the results of the study, the main issues and directions of further development of prison architecture are indicated, and the author proposes models of optimal architectural and planning organisation in terms of security, surveillance and access control.

    Keywords: security, prisons, penitentiary architecture, architecture, detention centres, design