The paper considers the problem of automatic detection of defects in the geometric parameters of steel ropes of elevator systems using computer vision methods. The features of flaw detection of moving steel ropes based on video sequences are analyzed, associated with the fragmentation of the image of some defects in adjacent frames and the variability of the geometric dimensions of the rope and the characteristics of the defect visible by the camera due to vibrations of the rope during movement. Taking into account the considered features, two algorithms have been proposed: to determine the defect of thickening/thinning of the rope diameter and the defect of undulation. The paper presents the results of experimental testing of algorithms on a special test bench and calculates the reliability indicators of defect detection by the proposed algorithms in the form of precision and recall of detection of each defect individually, as well as the average precision and recall of detection of both considered defects of geometric parameters of the rope as a whole.

Keywords: steel rope defects, instrumental control, non-contact flaw detection, computer vision

The problem of safety in the construction of buildings and structures has always been and remains very relevant. In our time of actively developing scientific and technological progress, new risk factors of a technogenic nature appear. Studying the survivability of buildings, and consequently the resistance of buildings to progressive collapses, is a very important task. This article examines the influence of the compliance of nodal connections of a metal frame on progressive collapse.

Keywords: progressive collapse, yielding of nodes, metal structures, survivability, special effects, calculation methods

The article discusses the areas of application of the deformation model and reviews studies related to its use for various design solutions and operating conditions. A method for calculating eccentrically compressed reinforced concrete elements that takes into account second-order effects is presented. This methodology takes into account the current provisions of regulatory documents. A selection of experimental data was made for flexible eccentrically compressed columns. Calculations of bearing capacity and deflections for selected samples were performed. Various forms of concrete deformation diagrams were used in the calculations. Based on comparison with experimental data, conclusions are drawn about the applicability of various types of diagrams for calculating bearing capacity and deflections.

Keywords: deformation model, stress-strain diagram, eccentrically compressed element, flexibility

This article is devoted to determining the main characteristics and properties of concretes made from different concrete mixtures based on Vietnamese materials. A total of 16 formulas of concrete mixtures were studied. Concrete samples were tested to determine deformations under prolonged loading. Based on the data obtained, the main creep characteristics were determined, these are the creep measure C0 and the creep coefficient ϕ, as well as additional characteristics including prismatic strength and the initial modulus of elasticity of concrete. The main purpose of this study was to determine the dependencies of the prismatic strength of concrete Rpr, as its main indicator, in relation to the creep coefficient of concrete ϕ. In conclusion, experimental data on the creep coefficients of concrete ϕ were compared with the normative values found according to SP 63.13330 and conclusions were drawn on the effect of concrete creep on its prismatic strength of concrete Rpr made from concrete.

Keywords: concrete, reinforced concrete, structures, materials, creep, deflections, deformations, prolonged loading

In connection with the revival of interest in wooden housing construction in Russia, the creation of specialized software systems for the calculation and design of buildings and structures made of wood is becoming relevant. One of the most popular systems in the world is light-frame housing construction. As one of the possible tools for automated design of light-frame wooden buildings, this article presents the FrameCAD program, developed at the Department of Metal, Wood and Plastic Structures of the Don State Technical University. Some of its capabilities are presented, allowing you to design wall fences of light-frame buildings, beamed wooden floors, perform calculations of individual frame elements taking into account the requirements of current regulatory documents and automatically generate albums of drawings of wooden structures in the domestic NormCAD program, as well as specifications for them factory made. FrameCAD has been tested in the design of a number of objects. The software product is developed by engineers who have many years of experience in the actual design and construction of light-frame buildings. It continues to be improved and supplemented, and in the future it may become a replacement for similar foreign complexes.

Keywords: wooden structures, software package, wall panels, beam overlap, automated calculation

The article deals with the peculiarities of the study objectives and test methodology for characterization of different contact zones organized in different ways and requiring different methodological approach for specimen fabrication and testing. The steel plate-concrete contact zone organized by stamping on the steel plate requires the use of steel molds to prohibit horizontal movement. The contact zone between the steel plate and the concrete, organized by the stamping on the steel plate requires the use of steel molds to prohibit horizontal movement. The contact zone of two wooden bars organized by epoxy glue with reinforcing fabric placed between the layers of glue is tested for shear without organizing the prohibition of horizontal movement. The contact zone formed at the connection of a steel plate and incompletely gained strength concrete, with the association of steel bars has features of fixing the actual strength of the concrete part of the specimen. The considered methods have both a number of common features and differences, which are taken into account in the proposed methods of fabrication and testing.

Keywords: contact zone, contact characteristics, test methodology, shear tests, stamping, composite construction

Improving calculation models of concrete based on experimental data, especially when studying the volumetric stress-strain state, is an urgent task. When calculating the containment shells of nuclear power plants under the influence of beyond design basis accidents, it is absolutely important to take into account the available safety margins of the materials used. Under volumetric loading, due to the work of concrete in cramped conditions, its strength and deformation characteristics improve, which is not sufficiently reflected in the regulatory documentation in force in the Russian Federation. Taking into account the analysis of existing test methods, based on the labor intensity and reliability of the results obtained, the optimal method of testing for volumetric loading was identified. The article contains the results of testing the selected test method, taking into account the improvement of the deformation measurement system. They confirmed the effectiveness of using the proposed methodology from the point of view of data reliability and relatively low labor intensity of work.

Keywords: concrete, volumetric loading test, volumetric strain sockets, deformation diagram

The purpose of the work is to develop a methodology for calculating the stress-strain state of three-layer structures made of composite material under the action of dynamic loads in robotic systems: semi-natural simulation stands, intended mainly for testing the flight characteristics. The stand consists of movable channels that ensure movement of the tested product in three degrees of freedom. The algorithm for creating a three-layer stand made of composite material is as follows. We assign the characteristics of the filler to the model of stand, create surfaces on the model and assign to the created surfaces the characteristics of a multilayer composite material with the orientation of the base of the layers along the lines of the trajectories of maximum stresses. Calculations of a three-layer stand with eight-layer load-bearing layers, with different orientations of the layers, were carried out to determine the structure of a multilayer composite material of maximum strength and rigidity based on theories of the destruction of multilayer materials stating that the destruction of one layer leads to the destruction of the multilayer material as a whole. The stress-strain state of a three-layer of the stand for semi-natural modeling of maximum rigidity and strength was obtained. The developed methodology is applicable to a wide class of problems of calculating the robotic systems made of three-layer composite material.

Keywords: material characteristics, multilayer composite material, modeling methods, three-layer structures, calculation, analysis

The use of closed methods for laying underground polyethylene gas pipelines using horizontal directional and directional drilling methods when crossing artificial and natural obstacles is considered. The results of calculating the geometric parameters of the working and receiving pits when laying polyethylene gas pipelines using a closed method using horizontal directional drilling are presented.

Keywords: polyethylene gas pipeline, closed installation method, horizontal directional drilling, directional drilling, dimensions of working and receiving pits

The loads on the power floors and column foundations of modern logistics centers can reach 6-9 t/m2 and 1000 t, respectively. At the same time, the step of the grid of exploration wells in the mined areas does not allow reflecting on the geological sections the exact geometry of the occurrence of weak, untreated soils of backfilling pits. The use of a method for strengthening man-made soils by pressing in prefabricated prismatic piles made it possible to compensate for the missing information from engineering and geological surveys by controlling the forces of indentation and thus determining the occurrence marks of more durable foundation soils.

Keywords: engineering and geological surveys, the territory being worked on, man-made soils, soil reinforcement with piles, geological section

Technological pipelines of compressor stations are one of the significant types of basic equipment that ensures uninterrupted operation during gas transportation. In this article, we paid special attention to the issue of safe operation of the pipeline strapping of the gas treatment plant for transportation, which is designed to dry gas to the required parameters required by consumers and is one of the main technological units of the compressor station. During the operation of the adsorber lines with "hot" and "cold" gases, the pipelines of the regeneration line are subjected to high variable temperature loads. Thus, the operating organization faces the problem of ensuring sufficient compensation for the linear expansion of technological pipelines during their periodic heating. The calculation of the service life of the piping and its stability with a matched axial bellows compensator has been performed. Various solutions to the reliability problems of these compressor station components are considered and analyzed. It is concluded that it is necessary to update the regulatory design framework and introduce continuous technical monitoring methods into the operated facilities.

Keywords: gas treatment plant, process pipeline, adsorber, safe operation period, temperature load, compensator

The article analyzes the heat-shielding properties of typical curtain-type ventilated façade (hereinafter referred to as CVF) systems used on multi-storey residential buildings in Moscow. We conducted analytical and visual studies, evaluated the technical condition by external features, including photographing the detected defects, thermographic scanning of facades, and took selective measurements of external geometric parameters, distortions, and structural properties for 18 objects in the city of Moscow. The level of defects in the thermal insulation layer at Moscow facilities was at least 50%. A gap of 10 mm at the joint of insulation slabs reduces the heat-shielding properties of the CVF fragment of the outer wall by 14.5–15%. The conclusions were drawn on the basis of the results of calculations of the reduced heat transfer resistance of a total of 18 CVF options from two manufacturers of the Kaptekhnostroy (aluminum CVFS subsystem) and Alfa-Prof (galvanized CVF subsystem) systems. When comparing these solutions, it is obvious that they are all inferior in value reduced resistance to heat transfer of the composite facade thermal insulation system. If the foundation is made of monolithic reinforced concrete or brickwork, the choice of finishing material does not matter. Moreover, the indicators of the reduced heat transfer resistance do not differ significantly. In the case of a base made of expanded clay concrete blocks, the galvanized steel subsystem is 2.9% (ceramic granite), 4.3% (fiber cement) and 4.6% (composite) more efficient.

Keywords: curtain-type facade system, ventilated, facing slabs, fasteners, defects, inspection, heat transfer resistance

The results of the coefficients of iciness for the northern and southern walls, in the attachment points of the frame of the ventilated facade for wall fences made of three-layer reinforced concrete panels with an internal thermal insulation layer are presented. The durability of the anchor attachment of the hinged ventilated facade is determined, depending on the frost resistance of the outer layer of the three-layer wall panel and the orientation of the wall to the north or south.

Keywords: hinged ventilated facade, reinforced concrete three-layer panel, attachment point of the hinged facade, ice coefficients, durability

Ultra high-performance or ultra high-strength concrete is a new class of cement-based materials with increased strength and durability. The widespread use of this concrete in construction practice requires theoretical and experimental studies of the stress-strain state of structures made from them. The article presents and analyzes the shear strength of I-shaped beams made of ultra-high-performance concrete tested by the authors. In the experiments, we varied the fiber content, the shear span, the shear reinforcement ratio, and the width of the compressed flange.

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

Modern domestic calculation methods and developed countries for determining the bearing capacity of monolithic reinforced concrete slabs for punching do not fully take into account all factors of design solutions and operating conditions. The available design provisions are made for the static operation of structures and there are no recommendations for taking into account the features of the dynamic impact on the overlap and the nature of the work of the node interfaces. The accepted empirical assumptions of the calculation, based on numerous experimental data, do not take into account the features of the stress-strain state of the coupling of the overlap with the column during destruction according to the punching scheme. This is due to the lack of computational models in which all the acting internal forces ensuring the resistance of the interface to penetration would be considered comprehensively. The complexity of the problem is due to the fact that the sections of the nodal interface are in an inhomogeneous stressed state. The stress-strain state of plates for punching under dynamic load is currently little studied. This article proposes a method for determining the bearing capacity of a symmetrical nodal coupling of a column with an overlap for punching under static and short-term dynamic loading. The proposed design model of the punching strength is based on the following prerequisites: the resistance to punching of a monolithic reinforced floor consists of the shear resistance along the surface of the reduced punching pyramid formed by the height of the compressed concrete zone; the strength of the concrete shear resistance increases due to volumetric compressive forces on the surface of the reduced punching pyramid; the angle of inclination of the faces of the punching pyramid depends on the loading speed. The obtained theoretical dependences are applicable under static and dynamic loading and are in satisfactory agreement with experimental data.problems in the field of video analytics. Numerous studies have shown that, despite the dynamism of processes in the field of information technology and the introduction of various tools and methods, the task of object maintenance still remains relevant and requires further improvement of previously developed algorithms in order to eliminate some inherent disadvantages of these algorithms, systematization of techniques and methods and the development of new systems and approaches. The presented article describes the process of step-by-step development of an algorithm for tracking human movements in a video stream based on the analysis of color groups. The key stages of this algorithm are: the selection of certain frames when dividing the video stream, the selection of the object under study, which is further subjected to a digital processing procedure, the basis of which is to obtain information about color groups, their average values and percentages of their occupancy relative to the object under study. This information is used for the procedure of searching, detecting and recognizing the selected object with an additional function of predicting the direction of movement on video frames, the result of which is the formation of the entire picture of the movement of the person under study. The materials presented in this paper may be of interest to specialists whose research focuses on issues related to the automated acquisition of certain data in the analysis of various images and videos.

Keywords: coupling of a monolithic floor with a column, static and dynamic load, punching pyramid, tangential stresses, concrete shear strength, punching strength

This article analyzes the main climatic indicators and considers domestic and foreign experience in the research and design of low-rise solar civil buildings in the conditions of the Republic of Tajikistan. Also, based on data from a number of scientists and preliminary studies, the basic principles of designing low-rise civil buildings, taking into account the location in the construction zone, were considered.

Keywords: climate, temperature, humidity, building, solar radiation, design, comfort, construction, insolation

This article investigates the moment redistribution behavior in corroded reinforced concrete (RC) beams. previous studies by different authors are reviewed, which shed light on the behavior of corroded statically indeterminate RC elements. The corrosion effects on the ultimate strength, deflection, and moment redistribution ratios are examined. The application of axial loads and location and severity of corrosion allowed for a comprehensive discussion of the moment redistribution behavior. The results showed that continuous RC beams with corroded reinforcement behave differently than simply supported RC beams. The corrosion process also affected the moment redistribution, providing additional safety to the RC structures. Existing research in this area is limited, and further investigations are required to address this knowledge gap and improve the understanding of the mechanism of moment redistribution in continuous corroded RC beams.

Keywords: corroded RC beams, statically indeterminate RC beams, moment redistribution, corrosion, accelerated corrosion method, ultimate strength, deflection, structures durability

During the reconstruction of historical buildings, it is necessary to carry out work on strengthening and strengthening structures. Reconstruction with preservation of the facade walls, which are an object of cultural heritage and form the street facade, deserves special attention. This type of reconstruction includes a complex of works to maintain the preserved structures. The work performed is temporary, but it significantly affects the duration and cost indicators of the entire reconstruction cycle. It is necessary to minimize this type of work in terms of economic and time costs. The purpose of this article is to analyze the existing systems of free-standing retaining walls used in the reconstruction of buildings, to determine the main technological parameters that affect the choice of the system as a whole.

Keywords: reconstruction, facade, facade retention, enclosing structure, construction, foundation, wall, assortment, expert assessment, installation, dismantling, fastening

The article presents an analysis of the phenomenon in which areas with elevated temperatures form in cities, and considers methods to combat this phenomenon. The article examines the causes of urban heat islands, including dense housing and the use of heat-trapping materials. Solutions are proposed such as increasing green spaces, using sustainable materials and proper urban planning. The article emphasizes the importance of creating comfortable areas for residents and sustainable development of the city in the face of climate change.

Keywords: heat island, surface temperature, hot areas, heat balance, city, suburb, planning

The article is devoted to the study of flange beam to column connections to analyze their nonlinear behavior. In the course of the study, a simplified analytical model was created using the method of variable elasticity parameters to determine the stress-strain state of these connections. The proposed mechanical model makes it possible to predict the strength, stiffness, ductility of joints, as well as possible types of fracture and deformation mechanisms of the bent elements of flange joints. This model can be useful for engineers and specialists in the field of design and analysis of civil structures. The proposed refined component model is an analogue of the Eurocode 3 model. The paper presents a numerical experiment on modeling the junction of a beam with a column by the finite element method. A comparative analysis of the results obtained with the results of tests of flange connections of steel building structures performed by the University of Sydney (USYD) is presented.

Keywords: flange connections, flange plate, stress-strain state, method of variable elasticity parameters, component method, refined component model, finite element method, elastic-plastic state, plastic hinge, modified stiffness, bending model of flange plate

Methods of calculation and design of building structures are considered that make it possible to provide trouble-free operation on time during the service life, and hence the level of reliability. According to the reliability indicator, the following scheme for standardizing the reliability of designed building structures is linked to the assessment of quality indicators of constructed structures. Indicators of design quality that are not related to strength, guaranteed with a given probability of failure-free operation, are introduced: geometric dimensions, modular deformation and elasticity, taking into account the properties of variability and technology. The appropriate safety factors are determined, ensuring mandatory protection of failure-free operation. A scheme for calculating design structures with the required level of reliability during the design, construction and operation of structures is being developed.

Keywords: method of calculation of structures, reliability, safety factor, strength class, reliability index, improvement of calculation of structures

The article presents the results of a comprehensive assessment of the deformability of a frame one-story, single-span building, the load-bearing structures of which are made of laminated wood. Constant and short-term loads were applied to the frame elements, the duration fraction was identified, the standard value was clarified, and the values of vertical displacements of the structural units were obtained. An assessment was made of the maximum deflections of the circuit elements from the standard load values with the maximum permissible valuese considered - on columns and in floor beams.

Keywords: one-story single-span building, permanent loads, short-term loads, standard load values, laminated board package, spacer system, boundary conditions, modulus of elasticity, stiffness, stress, displacement, CAD

The main designs of dust settling chambers of metallurgical enterprises are considered, an analysis is given from the point of view of the type of metallurgical furnaces, their power, and schemes for removing gases from them to gas cleaning equipment. The movement of gas flow in chambers of various designs was studied using the SolidWorks software product with the FlowSimulation application, which made it possible to establish the behavior of the gas-air flow depending on the design of the dust settling chamber.

Keywords: dust settling chambers, steel melting furnace, solid particles, modeling, gas-air flow, bag filter, gas exhaust path

At the present stage of increasing competition, the increased level of threats to the economic condition of business entities in any sector of the economy requires special attention. Enterprises of this industry annually emit aerosols of various composition and origin into the atmosphere: iron, vanadium, aluminum oxides, manganese oxides and other heavy metals. One of the components of safety is environmental safety and ensuring safe working conditions. The chemical composition of the dust-gas-air mixture of metallurgy enterprises is considered in the article, and the dispersed composition of aerosol emissions is determined. The data of the results of microscopic analysis of the fractional composition of dust based on the data of integral dependences of the density of distribution by equivalent sizes (diameters) D for the ingredients accepted for the study allowed us to determine the average median values of equivalent dust diameters.

Keywords: metallurgy, aerosol, electric steelmaking shop, dust-gas-air mixture, dispersion analysis, average median diameter, dh 50

The modeling and calculation of the proposed reinforced concrete slab using modern software systems are described. The description of the proposed reinforcement design is given. The results of the experiment on full-scale samples and the results of the calculation of the 3D model are shown. A comparative analysis of the data obtained during the experiment with the data obtained during modeling is performed.

Keywords: reinforcement of building constructions, hollow core slab, Experiment, modeling and calculation, comparative data analysis