The article provides a comprehensive analysis of defects in monolithic reinforced concrete structures, commonly encountered during the construction of multi-storey buildings. The main types of defects and damage are discussed, such as cracks, concrete spalling, destruction of the protective layer, exposure and corrosion of reinforcement bars, formation of cavities, concrete overflow, gravelly texture, geometric deviations, and cold joints in concreting. Their general description, causes of occurrence, classifications, parameters, and consequences for the operational characteristics of the structures are presented. Special attention is given to modern diagnostic methods and repair technologies, which significantly extend the service life of buildings and enhance their safety throughout their lifecycle. The results presented can be used by engineers, builders, and repair specialists to optimize construction processes, control the quality of work, and ensure the timely elimination of identified defects.

Keywords: Inspection of structural elements, reinforced concrete, defects of monolithic structures, cracks, reinforcement corrosion, repair, concrete quality, cold joint, monolithic construction, concrete surface quality

The article is devoted to the development and calculation of cable-stayed structures used as protective barriers against unmanned aerial vehicles (UAVs). The analysis of the design and calculation of cable-stayed structures for protective enclosing structures designed to counter UAVs is carried out. The main stages of the calculation are considered, including the determination of external loads, dynamic modeling of shock effects, finding the dynamicity coefficient through energy loss, and the conversion of kinetic energy into potential energy. The prospects for the development of this area are discussed with an emphasis on modularity, adaptability and integration of systems. It is concluded that cable-stayed structures are a promising solution for protecting critical facilities, providing high strength with minimal weight and cost.

Keywords: cable-stayed structures, impact impacts, protective enclosing structures, unmanned aerial vehicles, dynamic loads, dynamic coefficient, impact energy, inelastic impact

The evolution of sports facilities built in the Krasnodar Region is covered from a scientific point of view. The relevance of historical research of these facilities in modern times is substantiated. The need to preserve sports facilities that have important architectural and cultural significance is noted. The illustrations are presented in chronological order, as well as brief historical information about the stadiums built in the 20th century. Primary attention is paid to the architectural and design features, innovative technologies of Krasnodar stadiums, taking into account further improvement and targeted transformation. The economic potential of sports facilities is identified as an important component of popularization and involvement of the population in a healthy lifestyle.

Keywords: sports facility, stadium, object, physical education, Krasnodar region, potential, architecture, construction, living environment

The article presents the results of experimental research on determining the inclination angles to the horizontal of the lateral faces of the punching shear pyramid for thick reinforced concrete slabs. It was found that for slabs with a thickness of 600 mm, the average inclination angle of the punching shear pyramid’s lateral faces to the horizontal is ≈ 34.0°. The article also noted that the value of this angle varies depending on the slab’s reinforcement ratio. The obtained data show that the actual stress-strain state of 'thick' slabs under punching shear significantly differs from the normative model. This necessitates changes to the standard design methodology for the punching shear strength of such structures.

Keywords: punching shear, reinforced concrete, thick slabs, crack inclination angle, experimental studies, design rules, size effect, contribution of longitudinal reinforcement

An analysis of work in the field of assessing the technical condition of building structures of industrial industrial buildings has shown that there are no uniform standards and criteria for assessing the technical condition of building structures of industrial buildings. There is no comprehensive approach to the issue of safety of industrial buildings that have completed their standard service life, taking into account the nature of changes in operating loads, degradation of the load-bearing capacity of the facility and the resulting risk of accidents. There is a need to develop uniform criteria for assessing the technical condition of building structures of industrial buildings, depending on the parameters of the identified damage (chip length, crack width, area of detachment of the protective layer of concrete, damaged reinforcement, etc.).The article presents an analysis of defects and damages in building structures of industrial buildings with reinforced concrete frames. Most methods for estimating the remaining life of buildings are based on the results of visual inspection of the technical condition of building structures and a subjective assessment by an expert. As a result of the analysis of defects and damage to industrial buildings, a method for assessing the technical condition is proposed based on the parameters of the identified damage (length, area, depth of damage).

Keywords: building structures, reinforced concrete frame, defects and damages, concrete destruction, reinforcement corrosion, concrete chipping along the edges, reinforcement of reinforced concrete structures, areas of possible damage

The article considers the influence of the technical condition of buildings on their additional deformations in the zone of influence of new construction. As a result of the survey, it was confirmed that the buildings of the historical development of the III category of technical condition were in an unsatisfactory condition. In accordance with this, a numerical calculation was carried out, as a result of which an option for strengthening their foundations with the help of piles made using jet technology was proposed. According to the preliminary numerical calculation, additional deformations of buildings of the III category did not exceed the maximum permissible values. The adopted option of strengthening in this case did not justify itself and the actual deformations of the buildings turned out to be higher than the limit values ​​already at the zero mark. Based on the monitoring data, it was found that the values ​​of additional settlements are constantly growing in the process of erecting buildings of the multifunctional complex. Based on the calculation data, graphs were constructed illustrating the discrepancy between the actual additional deformations and the calculated values ​​depending on the category of the technical condition of the buildings and their location in the zone of influence of the pit. Thus, when determining the zone of influence of new construction in close proximity to historical buildings, it is necessary to take into account their technical condition and operational safety.

Keywords: technical condition category of buildings, zone of influence of new construction, additional deformations, estimated and actual settlements of buildings

Additive manufacturing technologies (AMT) has become one of the main trends in the development of innovative technologies in construction sector. The study examines the implementation of AMT using practical and illustrative example of its utilisation. In order to demonstrate and describe the sequence of steps 3D model of undersized building was created using fused deposition modeling (FDM). The methodology applied is model-driven. It was chosen in order to collect the experience, compare it with previous studied and use to the realistic manufacturing process. The aim of this paper was to identify possible limitations and challenging issues requiring further consideration and development. The main assumptions of this experiment are stated below with the purpose to explain the results obtained properly. In this study limitations of the previous studies are highlighted and possible solution methods are described referring to literature review and analysis. The main steps of AMT are shown step by step aimed to consistently study and reproduce the real process. The obtained information could broaden the current knowledge and help the researchers to apply the 3D printing (3DP) to access the full potential of it. Moreover, the paper also hypothesized the possible future directions for the future studies. Overall, the current key challenges to overcome in the nearest future are presented and discussed with a view to enable clean insights of AMT integration in construction sector.

Keywords: additive manufacturing, additive construction, construction technology, construction automation, digital construction, 3D printing, 3D model, civil engineering, emerging technology, fabrication, construction design, technology adoption

Numerical analysis of stress-strain state of monolithic slab with account of corrosion damage of concrete and reinforcement of compressed and tensile zones in the span part of the slab in PC LIRA-SAPR is carried out. 6 variants of corrosion damage depending on the area of spreading and degree of degradation are considered. The calculations have been carried out taking into account physical and geometrical nonlinearity. The peculiarities of structural deflections changes at different variants of corrosion damage and loading levels of the floor slab have been revealed. Redistributions of forces in spans and on supports arising at local changes of concrete and rebars stiffnesses are analyzed. No structural failure stage has been identified for the adopted design characteristics and damage variants.

Keywords: monolithic slab, corrosion damage of reinforced concrete, numerical analysis, redistribution of forces, bearing capacity, deformation capacity

The article presents the results of the second stage of a study to assess the load-bearing capacity of a running meter of a centrally loaded wall of various thicknesses, heights and strengths made of masonry. The second stage includes the study of masonry walls with elastic characteristics α = 200, 350, 500, 750 and is a logical continuation of the first stage, in which masonry with elastic characteristics α = 1000, 1200, 1500 was studied.The results of the study make it possible to minimize the use of a software package for preliminary determination of the bearing capacity of a centrally loaded stone structure and can become part of a practical guide for engineers involved in the technical inspection and design of masonry structures.

Keywords: bearing capacity, wall, stone structure, elastic characteristic of masonry, centrally loaded element, stone, brick, block, masonry mortar, coefficient of longitudinal bending, flexibility

The article is devoted to numerical modeling of corrosion-damaged reinforced concrete columns under low-cycle horizontal loading by static load in LS DYNA software package. The comparison of numerical calculation and experimental data on research of strength of reinforced concrete columns with corrosion damage of reinforcement under low-cycle horizontal loading is carried out.

Keywords: corrosion, reinforcement, seismics, reinforced concrete, corrosion damage, low-cycle strength, numerical modeling

The article discusses the theoretical, methodological and applied aspects of the development of organizational and technological solutions for quality control of structures built using the "white bath" technology in civil engineering. The characteristic of this technology as a method of integrated waterproofing based on the use of waterproof concrete and a joint sealing system without the use of external protective coatings is presented. Attention is paid to identifying factors affecting the quality of the structure, including the composition of the concrete mix, the conditions of production and laying of concrete, the design and installation of joints. The paper proposes a methodology for building a quality control system that includes a step-by-step process management algorithm, formalization of evaluation criteria using mathematical modeling, and consideration of current regulatory requirements. The practical implementation of the proposed solutions at a specific construction site demonstrated a reduction in the proportion of defects, an increase in the strength of concrete and the water resistance of the structure, and an improvement in the technical and economic performance of construction. A comparative analysis of the effectiveness of a number of key parameters is presented. Conclusions are drawn about the expediency of introducing the "white bath" technology in a complex hydrogeological environment and the high practical significance of the developed organizational and technological solutions is confirmed. The work is aimed at specialists in the construction industry, designers, engineers and the scientific community involved in improving the reliability and durability of concrete structures.

Keywords: white bath, concrete, waterproofing, quality control, seams, water resistance, sealing, technology, building structure, additive, seal, strength, model, standard, defect

The paper analyzes existing 3D printing technologies in the context of application in construction. The experience of 3D printing application in commercial projects is considered. Scientific research on the improvement of various technologies is summarized. 3D printing technologies promising for construction - wire-arc and ultrasonic additive manufacturing - are identified.

Keywords: 3D printing, construction, additive technologies

The area where the floor is supported by a column is one of the most critical areas in buildings with a load-bearing system made of monolithic reinforced concrete. This is due to the high concentration of forces and, as a consequence, the densest reinforcement within the floor. When designing such structures, the problem of initially setting the thickness of the floor from the conditions of punching arises, without yet having a spatial calculation scheme that allows correctly determining the bending moments in the node working on punching. In the article, conditions are obtained for the necessary and sufficient thickness of floors with and without transverse reinforcement depending on the punching force F in the column.

Keywords: punching shear resistance, flat reinforced concrete slab, static load

The technology of ensuring accident-free operation of tunnels and underground structures is presented. An analysis of various technical solutions currently used in the open and semi-closed method of constructing underground structures for transport purposes is given. Methods for reducing the occurrence of emergency situations during the operation of tunnels and underground structures are proposed.

Keywords: building structures, metal structures, energy facilities, stress-strain state, technical expertise

Rapid urbanization in developing countries, particularly Iran and Turkey, has increased environmental challenges that require systemic and engineering-based strategies for managing sustainable development projects. This study presents a structured approach to engineering modeling and managing urban environmental projects using five metropolitan areas: Tehran, Mashhad, Isfahan, Shiraz, and Istanbul. Particular attention is paid to the socio-economic impacts of implementing sustainable initiatives, including job creation, cost reduction, and improved urban quality. Istanbul’s successful experience in integrating waste-to-energy systems and switching to electric public transport is compared with less effective and disparate practices in Iranian cities. Based on the analysis, policy recommendations are developed to promote interregional cooperation and form a coherent sustainable development framework for policymakers and urban planners.

Keywords: sustainable development, environmental project management, socio-economic effects, renewable energy, circular economy, waste-to-energy, urban infrastructure, Tehran, Mashhad, Isfahan, Shiraz, Istanbul

In this paper, an analysis of the calculation results is carried out, which makes it possible to assess the real impact of impact and explosive effects from UAVs on the strength of reinforced concrete structures. Load limits are set, depending on the four most common types of walls. The previously published classification made it possible to identify the main parameters necessary for a detailed load calculation.

Keywords: extreme loads, explosion, self-supporting walls, reinforced walls, non-reinforced walls, load-bearing walls, UAVs, strength testing, building structures, shock waves

The reuse of ash and slag waste from coal combustion is of great economic and environmental importance. The most material-intensive area of their reuse is the stabilization of ash and slag mixtures with Portland cement for the construction of layers of highways. A technical understanding of the processes of structure formation in stabilized ash and slag mixtures makes it possible to regulate the final properties and quality of the layers of road clothing and the roadbed. Strengthening of ash and slag mixtures with Portland cement makes it possible to increase the physical and mechanical properties of ash and slag mixtures: strength, frost resistance, density, etc.

Keywords: ash and slag mixtures, stabilized ash and slag mixtures, structure formation of stabilized ash and slag mixtures, sportland cement, microstructure of the ash and slag mixture

The loading history, including duration, stress level, number of cycles and environmental influences, also affects concrete performance by increasing strength while reducing deformability. Under long-term service, concrete can exhibit elastic behaviour until stresses in the order of 70-80% of the expected compressive strength are reached. The plastic and viscous properties of concrete play an important role under dynamic loading, determining its dynamic hardening capacity. Thus, long-term operation significantly alters the dissipative properties of concrete and affects its response under accidental dynamic effects. The aim of this study was to assess the extent to which the deformed state of the frame as a result of the erection sequence, creep and shrinkage strain accumulation influences the collapse resistance in an emergency situation.The process of deformation of reinforced concrete frame of a multi-storey building in an emergency design situation was modelled, taking into account the stage of construction and different age of concrete at the moment of load application. The computational analysis was performed in quasi-static formulation in Scad Office 21.1.9.9 using the ‘Assembly’ module.According to the results of the study, deformations and forces in the elements of the load-bearing system after the initial local collapse in it have been obtained and analysed. It is shown that when taking into account the sequence of building erection, accumulation of creep and shrinkage deformations, the building resistance to progressive collapse decreases.

Keywords: monolithic reinforced concrete frame, progressive collapse, creep, shrinkage, modulus of elasticity, modulus of deformation, static-dynamic loading

The installation of foundations of production facilities on sites subject to karst formation and suffusion processes in conditions of weak soils is a serious problem in the design and construction of large distribution centers. In such a situation, it is necessary to calculate the load-bearing elements of the building for the effect of the lack of reaction of the base under the sole of the foundations on a site with a diameter of 3.0 m, located in the most unfavorable places from the point of view of structural work. Such unfavorable locations of a karst sinkhole can be determined by digitally constructing "influence functions" and obtaining "envelope" diagrams of pressure on the base, foundation sediment, and structural reinforcement. If the maximum allowable precipitation of the foundations obtained by calculation is exceeded, it is possible to strengthen the soils by layer-by-layer recycling, which will allow reaching the normative indicators.

Keywords: karst formation, suffusion, sinkhole, calculated combination of loads, special combination of loads, reinforcement, foundation sedimentation, ground pressure

This article examines the support structures of a wind turbine designed for operation in the extreme climatic conditions of the Russian High North. The relevance of the study is driven by the strategic objectives of developing the Arctic zone of Russia and the necessity to account for specific environmental and climatic factors in the design of energy infrastructure. A modular structural system is proposed, taking into consideration transportation and technological constraints associated with Arctic wind turbines. A CAD-model of the structural system has been developed, comprising a three-section tubular conical tower and a compound pile cap with a three-point support configuration. CAE-based simulations were conducted to evaluate the load-bearing capacity of the structural system under extreme load combination. The results demonstrate that the proposed structural configuration meets transportation limitations while ensuring the strength and stability of the Arctic wind turbine under critical load combination. The proposed design solution is suitable for simplifying transportation and on-site assembly of Arctic wind turbine in remote northern energy infrastructure projects.

Keywords: Arctic wind turbine, modular structures, supporting structures, CAD modeling, CAE simulation, permafrost

The article analyzes the issues related to the implementation of construction control at the facilities of existing enterprises during their reconstruction. The authors conduct the research based on the use of methods of scientific analysis, synthesis, generalization and systematization. The work uses domestic and foreign scientific sources, examines the experience of advanced construction control technologies and their implementation practices. Special attention is paid to the use of digital technologies, such as monitoring systems, automated controls and modern software solutions. The theoretical basis of the research was scientific works on construction control, regulatory legal acts and standards, as well as publications on modern methods and approaches to the reconstruction of enterprises. The empirical part is based on the analysis of real data on construction control at enterprises, including identifying problems and evaluating the effectiveness of applied solutions. As a result of the research, an optimized structure of construction control has been developed, innovative technologies and recommendations for their implementation have been proposed. The effectiveness of the new model has been evaluated, showing its advantage over existing approaches. The theoretical significance lies in an in-depth understanding of modern methods for performing construction control, including the use of digital technologies. The practical significance of this work lies in the potential of applying the proposed solutions to improve the quality of enterprise reconstruction, which in turn contributes to the sustainable development of industry and the reduction of operational risks.

Keywords: construction control, operating company, reconstruction, entrance control, operational control, acceptance control

The paper considers the problem of the stress state of a rock array with continuous inhomogeneity. This type of inhomogeneity can be observed in rock arrays with cavities created by explosion. In this case, the dependence was chosen when the main mechanical characteristics depend only on one coordinate - the radius. It was also taken into account that the chosen dependence gives an opportunity to obtain relatively simple methods of solving the problems. The chosen calculation scheme of the problem allows to reduce it to the solution of one-dimensional task. For the case of the centrally symmetric problem we consider the solving equation, which is an ordinary inhomogeneous differential equation of the second order with variable coefficients. Using the substitution of variables, we can proceed to the solution of the hypergeometric equation. Solutions of hypergeometric equations are given in the form of hypergeometric series, which are known to converge. Using inverse substitutions, the stresses are found. The stress state of the rock array at different degrees of its heterogeneity is determined. The results are presented in the form of graphs. Comparison with similar solutions for homogeneous arrays is carried out. The presented results allow us to conclude that when solving problems on the stress state of rock arrays with cavities, it is necessary to take into account the heterogeneity of the arrays obtained in the process of creating such cavities with the help of explosion.

Keywords: heterogeneity of the medium, rock array, spherical cavity, stress state

In the process of developing a plot of the junction field, the theoretical calculation of the load capacity and the permissible load on the piles is carried out, based on which the number of piles and their arrangement are decided. The results of theoretical calculations are in some cases underestimated when compared with actual values, and the application of theoretical calculation may lead to an increase in construction costs. The article examines the change of pile size and position in a swave field after the actual results of the field tests are obtained. The technical-economic comparison was carried out and the conclusion of the effectiveness of the adopted solution for the three designed houses was drawn.

Keywords: pile, load-bearing capacity, the maximum weight load, pile field, techno-economic comparison

The article contains the results of the inspection of power transmission line structures within the framework of the preparation of design documentation for the reconstruction of cable racks and power transmission line supports due to the increase in the diameter of cables and, as a consequence, the increase in the load on the racks located in the Chaunsky District of the Chukotka Autonomous Okrug. The article presents a geodetic survey of load-bearing structures (determination of deflections and displacements of structures), lists of defects and damages, verification calculations of structures, and measures to strengthen structures.

Keywords: bearing capacity, inspection of structures, overhead power lines, wooden structures, supports, overpasses

The cargo turnover of modern distribution centers of network operators reaches hundreds of thousands of tons per year. The technological load on the floors in the warehouse part of the building is 8-10 t/m2 (80-100 kPa), on the floors – up to 2.4 t/m2 (24 kPa). These loads transfer significant pressure through the foundations of the frame to the ground, which, with large sole sizes and mutual influence, increases the lower boundary of the compressible thickness and, as a result, the draft of structures. In the presence of weak soils at the base, precipitation reaches exorbitant values. The situation is aggravated by the high groundwater level, which also increases the sedimentation of foundations. The article presents and analyzes options for solving the problem by strengthening the base by compacting the top layer and cementing it to different depths depending on the pressure and construction of the foundation.

Keywords: reinforcement of the base, recycling, permissible calculated precipitation, calculated soil resistance