Vol 19, No 5 (2024)
Architecture and urban planning. Reconstruction and refurbishment
Development of “non-places” by means of designing small architectural forms made of metal
Abstract
Introduction. The purpose of this paper is to study the main cultural approaches to the process of designing small architectural forms made of metal.Materials and methods. They are determined by the set goals and objectives. Methods of comparative (diachronic and synchronous) analysis, various methods of observation of modern cultural processes and phenomena were used. During the work on the paper, a significant amount of empirical data was analyzed, including the work of contemporary metal artists.Results. Understanding cultural processes and phenomena will allow to develop modern design of small architectural forms made of metal, to use the ideas of the paper in the educational and creative process. Art metal, one of its three main directions — architectural metal, small architectural forms occupy an important place in the formation of a single value-semantic architectural landscape of a modern city. The redundancy of space and time inherent in our present leads to an increase in the number of “non-places” (where there is no place for an individual) in the urban landscape. The space of “No place” is undefinable — neither through identity, nor through communication, nor through historical parallels. Small architectural forms (SAF) help to master “non-places” artistically (meaningfully), turn them into “places” of power, and fill the landscape with meaning. Development of “non-places” by means of designing SAF made of metal becomes an important task for a modern author.Conclusions. Further development of the design of small architectural forms in the XXI century, as well as culture in general, is associated with increasing mobility, built-up communication system and developed information field. Art metal, as one of the most ancient occupations of mankind, preserves invaluable heritage and experience of the past, and within the framework of modern art culture initiates the creation of innovations based on new materials and approaches, contributing to the development of creative thinking and creative freedom.
Vestnik MGSU. 2024;19(5):677-684
677-684
Phytoremediation potential of green spaces in the city
Abstract
Introduction. The deviation from average temperatures is currently 1.5 °C. If climate change continues, and due to anthropogenic influence, air temperature rises to 3–4 °C, then abnormally high heat waves will occur almost every year, bringing with them intense slow-moving rains. A review of more than 15 global programmes to implement green infrastructure in cities from the inception of this term in the 1970s and up to the present has been carried out. All of them have common long-term goals that coincide with the recommendations of the World Meteorological Organization and the United Nations Office for Disaster Risk Reduction.Materials and methods. The authors continue their detailed study of the intersection of Leninsky Prospekt and Lobachevsky and Obruchev streets in Moscow. The cadastral unsettledness of the research area and the creation of the specially protected area “Landscape Reserve “Forest on the Samorodinka River” in 2020 create additional opportunities for the collection of stormwater and implementation of phytoremediation technologies.Results. The authors carried out an analysis of the state of protected areas adjacent to the research area, noted plants that are endangered and listed in the Red Book. The approximate list of plants for use in phytoremediation facilities is given.Conclusions. It is necessary to use green areas in the city to reveal phytoremediation potential. Properly selected plants that are sustainable in the urban environment will help to improve the existing natural resource, increase the recognizability of the urban environment and add new socio-cultural scenarios for residents to permanent use.
Vestnik MGSU. 2024;19(5):685-712
685-712
Construction system design and layout planning. Construction mechanics. Bases and foundations, underground structures
Prediction of aerodynamic coefficients for twisting shapes of buildings and structures based on machine learning and CFD-modelling
Abstract
Introduction. Research was carried out on the application of machine learning to predict aerodynamic coefficients on buildings and structures with twisted form configurations. Data from aerodynamic simulations using numerical modelling in ANSYS CFX was used for training. The quality of predictions made by various machine learning models was evaluated in comparison to numerical simulations. Conclusions related to the use of machine learning models for determining wind loads on buildings and structures are drawn.Materials and methods. Python programming language and the following libraries, Pandas, NumPy, Scikit-learn, and Matplotlib were used to analyze the obtained results and to develop the machine learning model. The study considered four machine learning methods: linear regression, decision tree, k-nearest neighbours, and random forest. Aerodynamic simulations based on numerical modelling methods in ANSYS CFX were used to generate the training data. The accuracy of different machine learning models in predicting aerodynamic coefficients was evaluated using the statistical measure of R-squared.Results. As a result of the research, a database of 217 numerical solutions was compiled for various angles of twist of the building’s form. These results include the distribution of aerodynamic pressure coefficients over the building’s surface, as well as aerodynamic force and moment coefficients (Cx, Cy, CMz) as a function of height. The data was used to train four machine learning models. The best-performing machine learning model (random forest) was verified by comparing it to the results of numerical modelling.Conclusions. Various machine learning models for predicting aerodynamic coefficients on buildings and structures were investigated. Conclusions were drawn regarding the applicability of machine learning methods as an alternative approach to determining wind loads.
Vestnik MGSU. 2024;19(5):713-728
713-728
Numerical and experimental study of the behavior of a protective structure under impact
Abstract
Introduction. In connection with the constantly existing threats of deliberate damage to the infrastructure of critical facilities using vehicles, the task of development and research of protective structures aimed at preventing this kind of damage becomes relevant and of practical interest. The application of steel ropes as the main load-bearing elements of such structures is substantiated.Materials and methods. The proposed numerical algorithm was used to determine the minimum permissible cross-sectional area of steel ropes based on the requirements for a protective structure in terms of resistance to impact caused by the collision of a car with a given mass and speed. The developed method is based on mathematical modelling of the conditional optimization problem. The objective function was the function of the longitudinal force arising in the steel ropes. At the same time, requirements were made to comply with the conditions of energy conservation and continuity of deformations, as well as strength limitations. A verification calculation of the designed protective structure was carried out in a commercial software package implemented on the generally recognized finite element method. The methodology of the full-scale experiment is presented. A full-scale experiment was carried out in order to determine the true distribution of deformations over the structural elements of the test object under impact.Results. The results of the experimental study are presented. A comparative analysis of the data obtained in the process of numerical and computer simulation, as well as in the course of a full-scale test, was carried out. A slight discrepancy in the values of the controlled parameters obtained by different methods was found.Conclusions. The proposed numerical algorithm for searching the minimum permissible cross-sectional area of steel ropes, based on the requirement of a given strength, confirmed its reliability, and the adopted design solutions of the developed protective structure proved their validity. The results of the research can be used in the design of such engineering structures designed for the physical protection of critical facilities.
Vestnik MGSU. 2024;19(5):729-739
729-739
Experience of implementation of Eurocodes in the design of steel structures in the Republic of Belarus
Abstract
Introduction. The Republic of Belarus is one of the first countries on the territory of the CIS, which introduced European design standards (Eurocodes) on its territory, while preserving the effect of building standards developed on the basis of Soviet SNIP. The republic accumulated considerable experience in the practical application and comparative analysis of these two systems of standards. The relevance of this study is contained in the discovery of the most distinctive features of normative documents, on the basis of which it is possible to determine further directions of scientific research and improvement of domestic norms.Materials and methods. Analysis and generalization of experience.Results. The paper presents the results of generalization of the experience of practical application and comparative analysis of Eurocode and CP in relation to the design of steel structures. The analysis of partial factors, classification of cross sections, welded and bolted joints is given.Conclusions. Methodological approaches to checking limit states and ensuring the reliability of steel structures in CP and Eurocodes are very similar, but there are differences in the values and sets of partial factors. When designing steel structures according to Eurocode, the methods of classification of cross-sections of rolled profiles produced according to GOST or TS need to be adjusted. Eurocode 3 provides more possibilities in the design of welded and bolted joints.
Vestnik MGSU. 2024;19(5):740-751
740-751
Calculation of a fibre concrete block as a part of locally reinforced truss nodes made of square hollow sections
Abstract
Introduction. Analytical and numerical study of truss nodes made of square hollow sections (SHS) with local fibre concrete filling is presented. The analysis of numerical calculation of a fibre concrete element as a beam on an elastic base as a local reinforcement of a truss node made of SHS under the action of the concentrated load from the adjacent strut is performed. The bearing capacity of a node with the direct adjacency of struts to the chords of trusses made of S+HS is almost completely determined by geometry and physical and mechanical characteristics of truss elements made of SHS. With the cross-section of the elements selected on the basis of the calculation of the bars, the load-bearing capacity of K-type connections may not be ensured. In this case it is possible to change the dimensions of the cross-section of a truss node made of square hollow sections. In the existing Russian normative documents, there is no data on the calculation and design of reinforcement of truss nodes made of square hollow sections by filling with concrete. In this connection, it is important to develop simple and reliable methods of strengthening such nodes, as well as appropriate methods of their calculation. The purpose of the work is to develop a methodology for calculating the fibre concrete block of analytical dependencies to determine the bearing capacity under concentrated load.Materials and methods. The research method based on the numerical modelling of local reinforcement of the node with fibre concrete is used. Materials for the nodes: chord and struts of the node — steel of S255 grade according to GOST 27772–2015 with design resistance 240 MPa, local filling — fibre concrete with elastic modulus not lower than 27,000 MPa and design resistance to compression Rb = 11.5 MPa.Results. The main results of the work consist in the analytical study of truss nodes made of square hollow sections locally reinforced with fibre concrete block, the development of a method for calculating the fibre concrete block as a beam on an elastic base based on the results of numerical experiments in the software package АNSYS.Conclusions. The significance of the obtained results for the construction industry consists in the fact that the possible approaches to the definition of different methods of calculation of fibre concrete block as a part of reinforced nodes of trusses made of square hollow sections were considered in order to reduce metal consumption and deformability. The results obtained in numerical studies of the base stiffness factor of fibre concrete block and the results obtained using the software package АNSYS showed that they are close to the results of calculating the stiffness factor of fibre concrete block in locally reinforced nodes of trusses made of square hollow sections reliably.
Vestnik MGSU. 2024;19(5):752-762
752-762
Reliability of spatial rod metal structures of high level of responsibility
Abstract
Introduction. Spatial rod metal structures of high level of responsibility are the most frequently used as structural systems for covering large spans of buildings and structures. However, progressive destruction can actively develop in these systems under unfavorable combination of factors. The aim of the research is to develop scientific justification of new approaches to the design of optimal spatial metal structures resistant to the development of progressive collapse of high level of responsibility with guaranteed levels of reliability of key and secondary elements.Materials and methods. The main research methods in the work are methods of structural mechanics in the form of the finite element method, methods of similarity theory, and methods of the theory of reliability of building structures.Results. As a result of the research work for the considered structures, a 2-stage algorithm for assessing reliability was developed, which differs from the previously developed ones by the possibility of assessing the development of progressive collapse. The results of its testing for frame-cantilever structures of coverings over stadium stands are presented in the form of established values of reliability indicators for a set of key elements. A similar assessment was made for the implemented reconstruction project of the long-span covering of the “Ilyichevets” sports complex (Mariupol).Conclusions. To assess the reliability of the studied structures, taking into account the tendency to the development of progressive collapse, a universal algorithm is proposed and tested in practical design, the main components of which are computer modelling of the process of successive failures of structural elements, and the establishment of failure probability values for the selected set of key elements. The studies carried out on the basis of its algorithm made it possible to identify a set of key elements of the cantilever part for the frame-cantilever coverings above the stadium stands, the failure of which initiates the beginning of an avalanche-like collapse, and to set limits for them to change the values of safety characteristics and survivability reserve. Additionally, the main provisions of the developed approach were experimentally tested during the development and implementation of the project of reinforcement of large-span bearing structures of the covering of the “Ilyichevets” sports complex (Mariupol).
Vestnik MGSU. 2024;19(5):763-777
763-777
Construction material engineering
Factors influencing the efficiency of building materials self-cleaning with photocatalytically active components
Abstract
Introduction. The use of building materials with photocatalytically active additives is considered as a promising solution to environmental and economic problems of the urban environment. In the field of building materials science the necessity of studying the microstructure of self-cleaning building materials and the influence of impurities on the efficiency of self-cleaning of materials with photocatalytically active additives is determined.Materials and methods. Red gypsum (production waste with photocatalytically active impurities), cement, building gypsum, microsilica, synthesized photocatalytically active titanium oxide – silicon oxide additive, and iron-based pigments were used. Tablet specimens of gypsum-cement-pozzolanic binder with various photocatalytically active components were made: photocatalyst additive, pigments, photocatalytically active oxide impurities. The microstructure of the specimens and the distribution of titanium and iron elements were studied using scanning electron microscopy. The efficiency of self-cleaning was determined by the change in the contact angle of a water drop on a surface coated with oleic acid.Results. The efficiency of self-cleaning of specimens with added and impurity photocatalytically active components was determined. The influence of added impurities on the structure of the material and the influence of the type and concentration of impurities on the efficiency of self-cleaning were revealed.Conclusions. Titanium oxide photocatalyst additive at a concentration of 4.4 % provides high self-cleaning efficiency, evenly distributed throughout the material without affecting the structure of the forming binder stone. Pigment (iron (III) oxide) provides sufficient self-cleaning efficiency at a concentration of 2–9 %, at concentrations of more than 2 % it is distributed unevenly, providing a small increase in self-cleaning efficiency indicators. With the joint introduction of titanium and iron oxides, deterioration in self-purification is observed due to the high degree of recombination of electron – hole pairs. Red gypsum with impurity oxides of titanium and iron has shown a high efficiency of self-cleaning, has a uniform distribution of impurities that do not have a clear effect on the structure of the material.
Vestnik MGSU. 2024;19(5):778-788
778-788
Hydraulics. Geotechnique. Hydrotechnical construction
Bearing capacity and settlement of clay foundations under block cyclic loading
Abstract
Introduction. The available methods of assessment of bearing capacity by deformations of foundations mainly take into account single static loads of short duration or cyclic loads with unchanged values during the whole period of operation. The effect of cyclic loading of non-stationary regimes on the behavior of soil bases is practically not studied. In this connection, the research was carried out to develop a method for calculating the settlement of the bearing capacity of clay foundations under block cyclic loading.Materials and methods. To achieve the purpose of this paper, experimental studies of clay foundations in triaxial compression and tray test devices, as well as theoretical studies to determine the bearing capacity and settlement of clay foundations under different loading regimes were carried out.Results. On the basis of existing calculations of bearing capacity and settlement of foundations and the study of the behavior of clay soils under cyclic loads, the equations in compact form are obtained, which make it possible to take into account the peculiarities of deformation of clay soils significantly reducing the complexity and accuracy of the calculations. The development of methods for calculating the bearing capacity and settlement of clay foundations under block cyclic loads is at a sufficiently high level.Conclusions. A method for calculating the bearing capacity of clay foundations under block cyclic loading is proposed and an engineering method for calculating the settlement of clay foundations is developed, based on the method of layer-by-layer summation, which takes into account the simultaneous change in the spatial stress-strain state and mechanical characteristics of soils in the process of mode block cyclic loading.
Vestnik MGSU. 2024;19(5):789-799
789-799
Comparison of methods for calculation of hydraulic characteristics of flow in non-pressure pipelines
Abstract
Introduction. Three methods of calculation of hydraulic characteristics of flow in non-pressure pipelines are considered. These methods are experimental, traditional and using SewerCAD software. Currently, further development of hydraulic methods for calculating turbulent flows in non-pressure pipelines is possible due to new measurement methods and effective software products. To improve the accuracy of hydraulic calculations, it is necessary to conduct experimental studies. The purpose of the work is to determine the hydraulic characteristics of flow in non-pressure pipelines using three methods and find the relationship between them. When carrying out hydraulic calculations of pipelines that supply water over long distances, it is necessary to place increased demands on the accuracy of the results, as this is associated with monitoring emergencies. When fluid moves without pressure, the driving force that determines the flow velocity is the component of gravity directed along the flow. To this day, the formula that determines the average velocity of a uniform flow in a non-pressure pipeline, proposed by A. Chezy, is widely used. The work established the dependence of pipe filling on the average flow velocity at various slopes. A comparison was made of the average velocity obtained as a result of experimental studies and calculations using SewerCAD programme. The validity of the practical use of the proposed methodology is confirmed by the results of processing experimental data both by the authors and by other researchers.Materials and methods. Methods of calculation of turbulent flows in non-pressure pipelines using experimental data, traditional methods and computer technologies were applied, which increases the accuracy of the calculated flow parameters and the reliability of the pipeline system.Results. The results of the experiment, SewerCAD programme and traditional method of velocity calculation at different flow rates for non-pressure polyethylene pipes with a diameter of 100 mm with a pipeline filling from 0.1 to 0.8 are presented.Conclusions. Laboratory researches were carried out to determine the hydraulic characteristics of the flow of a polyethy-lene pipeline with a diameter of 100 mm. Corresponding dependencies for the average velocity between the experimental results and SewerCAD programme for a non-pressure system were obtained.
Vestnik MGSU. 2024;19(5):800-810
800-810
Technology and organization of construction. Economics and management in construction
Organizational and economic aspects of residential buildings renovation with decorative elements on the roof
Abstract
Introduction. The problem of preservation of decorative elements on the roofs of multi-apartment residential buildings is considered. The authors note the historical and architectural value of such structures in creating the appearance of the city. An analysis of the current technical condition of decorative elements of roofs is carried out using the example of individual apartment buildings in Samara and, based on a comprehensive analysis, recommendations are given for their further operation. The problematics is investigated by the authors using the example of Samara city and, accordingly, are based on the practical basis of this city. At the same time, the questions and proposals posed in the paper are relevant and can be extended to the residential development of most Russian cities. This is due to the fact that the organizational and legal field of this problem is established at the level of federal legislation, and in the regions it develops only in the form of not the most significant features.Materials and methods. When developing the present problem, the authors used a set of generally accepted research methods — observation, comparison, measurement, abstraction — in adaptation to the object and subject of research. The research is based on the materials and results of the author’s own research in relation to technical, cost and regulatory parameters of the repair of decorative elements of flat roofs of multi-apartment high-rise buildings, made according to a standard and individual project in Samara city.Results. The regulatory and legal framework in force in relation to the overhaul of the common property of an apartment building is analyzed. Defects and problems were identified — corrosion of metal structures, destruction of wooden elements. The impact of dismantling of structures on the appearance of buildings is assessed. A comparative assessment of the cost of repair and restoration of roof elements is given. The current regulatory framework for overhaul in apartment buildings is analyzed. It is noted that there is no clear regulation of financing the repair of the roof structures under consideration. The estimated cost of overhaul of additional roof elements is determined according to alternative options for its production. The conclusion is made about the need for an integrated approach, taking into account the technical condition, financial capabilities and legal regulation to solve the identified problem.Conclusions. Proposals are made to improve the normative-methodical and normative-technical mechanisms to ensure the safety of historically and architecturally valuable elements of roofs and the safe operation of apartment buildings in Samara.
Vestnik MGSU. 2024;19(5):811-825
811-825
Using lean manufacturing tools in materials supply management during the life cycle of a construction project
Abstract
Introduction. When choosing the Engineering, Procurement, Construction (EPC) contract model, the life cycle of construction projects is managed by a specialized contractor organization. This form of construction project management is relatively new for Russian developers, and its successful implementation depends on various organizational and technical solutions, in particular, logistics management. The research problem is related to the existing risks of organizing the supply of material and technical resources during the implementation of construction projects using the EPC model, which have a negative impact on the most important indicators of construction efficiency, such as timing and cost. The paper describes strategies for preventing risk events that occur when planning the supply of material and technical resources during the life cycle of construction projects (risks of price changes, risks of violation of contractual obligations, risks of changes in the quality of delivery, reputational risks and risks of significant changes in demand). The problems of risk mitigation using lean manufacturing tools were solved.Materials and methods. The methodology and standards of project management as applied to the processes of material and technical support of construction, as well as methods of calendar-network planning, methods of project content decomposition, methods of contract strategy of construction projects implementation and elements of the methodology of package-node method of construction were used.Results. The results of the research are described and recommendations are given for the practical use of the flexible project management tool known in international practice as Just In Time.Conclusions. A justification for the use of the proposed planning tool as an activity to reduce risks associated with the supply of materials and improve the efficiency of life cycle management of construction projects is presented.
Vestnik MGSU. 2024;19(5):826-835
826-835