The article presents the results of comparing numerical modeling of wooden structures with laboratory and full-scale tests. In the course of the work, numerical models of the material were created in the Ansys Workbench software package from volumetric finite elements with a variant set of physico-mechanical parameters simulating the behavior of real wood. The simulation parameters were based on the laboratory testing results of a solid wood beam. The simulation results were compared with the full-scale test results of a composite wood slab. Modeling of constructions was carried out in the form of linear, bilinear and multilinear models.
Keywords: solid wood beam, composite wood slab, bilinear finite element model, multilinear finite element model, stress-strain state
The article is devoted to the study of the influence of the choice of the calculation scheme on the accuracy of the engineering assessment of the behavior of monolithic reinforced concrete frame structures. Various types of models are considered: rod, plate and volumetric, taking into account both linear and physical nonlinearity. It is emphasized that the adequacy of accounting for the spatial interaction of elements, the reliability of the assessment of forces and stresses, as well as the possibility of optimizing design solutions, especially under seismic and wind loads, depend on the correctness of the adopted calculation scheme.
As part of the study, a single-span reinforced concrete frame was modeled, the load on which varied from 5 to 55 kN. A comparison of the calculated results with experimental data was carried out. It is shown that models that take into account physical nonlinearity and use more detailed modeling (for example, volumetric finite elements) provide the greatest accuracy in predicting deflections and stresses in the structure.
The obtained results confirm the necessity of a careful approach to the choice of the calculation scheme in design, especially in the design of high-rise buildings and structures in seismically dangerous areas. Recommendations are made on the rational use of models of different levels of detail in engineering practice.
Keywords: linear calculation, nonlinear calculation, frames, reinforced concrete, deflections, modeling
The main design features and elements of industrial shaft furnaces are described. It is indicated that one of the undesirable phenomena in a shaft furnace is a large temperature gradient along its height; in this regard, the processes of air mass transfer through various parts of the furnaces are considered. The relationships and limitations that determine such a negative effect as the possibility of external air diffusing into the furnace through its walls are formulated. The results can be used to increase the quality of shaft furnace designs and the applied heat treatment processes.
Keywords: electric furnaces, heat treatment, tightness, gas permeability
A system of expert-analytical methods for decision support at the design stage of multi-apartment residential buildings has been developed. The objective of the study is to economically evaluate the developed methods at the design stage of construction projects. Fuzzy logic is used as a mathematical basis for intelligent automated decision support systems. The method for assessing the investment attractiveness of residential complexes provides decision support based on the average area of an apartment and the number of apartments per floor. The method for assessing the attractiveness of building a multi-storey residential building takes into account the class of housing, the height and area of the building. An economic justification for the use of expert systems is provided and it is shown that calculating the construction attractiveness coefficient allows increasing the profit of a construction organization within 30% due to the use of empirical knowledge and specialized engineering solutions.
Keywords: intelligent automated system, design, multi-apartment residential building, economic assessment, investment attractiveness, fuzzy logic
The article presents the results of static and dynamic calculations of a 14-storey administrative building with two underground floors. The building is located in the city of Sochi. The seismicity of the construction area is 9 points. As a result of calculations under seismic influence, characteristic isofields of movements of the building system in different directions, stress isofields in load-bearing monolithic reinforced concrete floors, and force plots in core elements were obtained. According to the results of the verification calculations of the load-bearing reinforced concrete structures of the building frame, it was revealed that the strength of the individual columns of the underground floors of the building is not ensured. Options for reinforcing columns using various options are presented: classic reinforced concrete cage, metal cage, pasting with composite tapes, steel-reinforced concrete cage. As a result of comparing all reinforcement options, the most optimal reinforcement option was adopted from the point of view of technology, economic feasibility and strength parameters.
Keywords: steel-fiber concrete, seismic, strength, reinforcement, dynamic calculation, cage, column, building, composite, comparison
The article considers the issues of increasing road safety in urban development in winter. The causes of snow and ice deposits and their impact on the comfort and safety of traffic, including pedestrians, are considered. A review of modern snow melting and road surface heating systems is provided, with the most effective examples of road surface heating projects being given. A comparative analysis and assessment of the effectiveness of road surface heating systems is performed, using a 1000 m2 car park as an example. Recommendations are given for the use of road surface heating systems.
Keywords: highways, hydrothermal systems, electrical systems, road surface heating
The article considers issues related to the development of the territories of the Far North and the Arctic, namely, issues of ensuring transport accessibility of the northern regions. The issues of relevance and demand for the construction of winter roads and ice crossings are considered. The features of the construction and operation of winter roads are studied. The main methods of strengthening and extending the service life of winter roads are considered and analyzed. Options for strengthening winter roads and ice crossings with geosynthetic materials are proposed and substantiated. Recommendations are given to reduce the environmental impact of measures to strengthen winter roads on the environment.
Keywords: winter roads, ice crossings, ice coverings, strengthening, reinforcement
A comparative study of three reinforcement options for reinforced concrete beams has been carried out: without reinforcement, with reinforcement with carbon tape both along the entire span length, and with partial reinforcement of the span zone with an end mechanical anchoring with carbon bundles. Numerical modeling has been performed, diagrams of bending moments and force distribution have been constructed, and the coefficients of the safety margin of the construction system have been estimated. The effectiveness of the schemes is substantiated in terms of strength, taking into account manufacturability and material consumption. It is shown that the use of mechanical anchoring with harnesses increases the reliability of the system while reducing material consumption.
Keywords: anchor harness, carbon fiber, load-bearing capacity, structural reinforcement, composite material
During long-term operation of reinforced concrete structures of buildings and structures under the influence of various loads and impacts, destructive changes occur, which lead to a decrease in the bearing capacity and serviceability, and, as a consequence, to the need to use structural reinforcement. In compressed elements, as is known, concrete destruction occurs due to reaching tensile stresses in the transverse direction of the strength limit. In this case, one of the effective methods for strengthening such structures is the creation of transverse ferrules from composite materials. At the same time, the studies show relatively low stresses in the elements of composite reinforcement when the structure reaches destruction. The current task of this study is to study the effect of prestressing elements made of carbon composite materials on changing the physical and mechanical properties of concrete under compression. The technology of creating prestressing is considered and the results of testing experimental concrete samples are presented. It was found that reinforcing elements with prestressed ferrules increases the strength of concrete by more than 2 times.
Keywords: concrete, reinforced concrete, compressed elements, reinforcement, composite materials, pre-compression, strength, deformability
Modern approaches to fire safety in modular buildings are analyzed. The features of these structures from the point of view of fire safety, innovative materials and technologies, regulatory requirements and successful examples of fire prevention measures have been studied. The importance of introducing advanced solutions to improve safety in the rapidly developing field of modular construction was emphasized.
Keywords: technology, module, fire hazard, fire safety, construction, material, requirements, risk, construction, implementation
The article provides a comparative analysis of the approaches to forecasting rutting used in Russia and the USA. Mechanistic–Empirical Pavement Design Guide (MEPDG) and domestic regulatory documents are reviewed, and their key differences in forecast accuracy, applicability, and calculation complexity are identified.
Keywords: rutting, forecasting of road structures, MEPDG, monitoring of road conditions, regulatory methodologies
The article examines the analysis of modern approaches to the organization of an inclusive environment in construction. The structure of the previously developed algorithm has been clarified, taking into account the key criteria of accessibility, informativeness, safety and comfort. The calculation of the adaptation of structures and services using the example of a standard apartment building (MCD) confirmed the effectiveness of the proposed approach. It has been established that the implementation of the algorithm, taking into account user needs, allows us to talk about optimal solutions for an inclusive urban environment, which is especially important in the context of the development of the "city within a city" concept.
Keywords: inclusive environment, construction, adaptation, accessibility, algorithm, criteria, urban transport, infrastructure, people with limited mobility, calculation, structural elements, safety, informativeness, comfort, apartment buildings
The article is devoted to the analysis and optimization of the stability of engineering structures to wind loads through the use of innovative structures of support and anchor foundations. In modern construction, when the requirements for reliability and stability of buildings have increased, special attention is being paid to the development of effective foundations capable of withstanding both compressive and pulling loads. Support and anchor foundations are presented as a comprehensive solution, including combined anchors and a monolithic slab (grillwork), ensuring uniform load distribution. The main focus is on the combined anchor, which acts as the main working element that receives the forces from the structure and effectively transfers them to the ground. Unlike traditional piles, the proposed design significantly increases the resistance to pulling due to the use of wire anchors with high load-bearing capacity.
Keywords: pile, conical tip, support and anchor foundation, support, combined anchor, grillage
The article is devoted to the assessment of the strength of reinforced concrete elements with defects and damages. It examines the main types of defects (reinforcement corrosion, cracks, deformations, shrinkage, spalling of concrete, etc.), their causes, and consequences. The document also presents various calculation methods for evaluating the residual load-bearing capacity of structures, taking into account these defects, including formulas for assessing the impact of corrosion, cracks, and other damages on the strength of beams. It is noted that current methodologies primarily focus on analyzing a single type of defect, while a comprehensive approach to evaluating multiple damages requires further research. The research results can be useful for developing recommendations for the operation and repair of reinforced concrete structures, as well as for improving methods of assessing their safety during long-term use.
Keywords: strength, load-bearing capacity, damage, defect, crack, corrosion, degradation, experiment, reinforced concrete, beam
The article presents a comparative analysis of the results obtained from the automatic determination of crack width in reinforced concrete structures using photogrammetric 3D targets and the manual method using a Brinell microscope. It also outlines the general conditions required to obtain accurate crack width measurements when performing photogrammetric surveys. The experience of using photogrammetric targets for determining crack width in reinforced concrete structures in Russia is limited due to the novelty of the method, the high cost of specialized equipment, and the complexity of data processing. Proper use of photogrammetric targets can significantly speed up the process of measuring crack width in monolithic reinforced concrete structures and improve measurement accuracy. This technology is particularly relevant for monitoring or field testing of structures that require regular crack width control.
Keywords: photogrammetric targets, monitoring, crack width, reinforced concrete, software suite, camera, focal length, lighting
This article discusses the problem of determining the dynamicity coefficients in case of local damage to the truss in the steel frame of an industrial building. The analysis of the resistance of steel frames to local damage is an important area in the design of industrial buildings, especially those that belong to the category of increased responsibility. Damage to individual elements of the load-bearing system can cause a redistribution of forces and lead to a progressive collapse.
Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production
The article presents research in the form of comparison of safety factors in guy ropes of building structures designed using the limit state method and ropes of mast structures related to power engineering facilities, specified in federal norms and rules. It is demonstrated that the use of safety factors for guy ropes of mast structures, justified by the theory of reliability, allows to effectively solve the problem of assigning rejection criteria for guy ropes, and can be used in developing recommendations for their inspection, technical diagnostics, and operation based on the existing known rejection criteria used for lifting structures.
Keywords: building structures, wooden structures, membrane panel, stress-strain state, radial beam dome, dome, membrane, design, experimental study
The article examines the use of unmanned complexes for finding and identifying defects in the construction of buildings and structures. The use of unmanned complexes integrated into practice for quality control of construction works of concrete and steel surfaces, as well as for regular inspections of buildings, insulation or ventilation systems is given. The prospects of using unmanned complexes for repair work, which contributes to improving the performance of the construction organization, were confirmed.
Keywords: machine vision, software, unmanned complex, survey, defect
In this article, we examined the permeability of concrete and the effect of corrosion processes on the durability and reliability of reinforced concrete structures. Attention is paid not only to the causes and mechanisms of corrosion, but also modern methods and strategies for protecting concrete and reinforced concrete structures from it are provided, aimed at extending their service life and ensuring operational safety. This knowledge will allow engineers and builders to plan and implement projects more efficiently, reducing the risks and economic losses associated with corrosion processes.
Keywords: corrosion of concrete, corrosion of steel reinforcement, permeability, reinforced concrete, durability, strength, reliability
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
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