Vol 19, No 6 (2024)
Construction system design and layout planning. Construction mechanics. Bases and foundations, underground structures
Review and comparative analysis of strength criteria for modelling non-linear behaviour of concrete
Abstract
Introduction. In recent decades, numerical methods for calculating concrete and reinforced concrete structures have developed significantly, taking into account the physically nonlinear behavior of the material. Such methods, in comparison with analytical ones, make it possible to describe the work of the material more accurately and reflect the main features of its stress–strain state. This makes it possible to perform more cost-effective and, in some cases, more reliable design solutions. Concept of the limit surface plays an important role in numerical methods. Limit surface, which is expressed by a condition (strength criterion), separates the elastic and plastic region of the material. Strength criteria must correspond to experimental data, provide a mathematically stable unique solution, and also have a set of parameters that can be easily determined from empirically based expressions or test data. The history of creation and improvement of concrete limit surfaces includes dozens of domestic and foreign works, many of which do not meet these requirements. The purpose of the current work is a comparative analysis of the most common strength criteria of concrete.Materials and methods. This study is based on the analytical generalization and systematization of the data received form domestic and foreign sources.Results. A detailed analysis of the most common domestic and foreign concrete limit surfaces was carried out.Conclusions. According to the analysis results, the comparison of the concrete limit surfaces was performed.
Vestnik MGSU. 2024;19(6):857-877
857-877
The effect of the stiffener pitch on the stress-strain state of the crane beam elements
Abstract
Introduction. A study of the stress-strain state of split crane beams was carried out, the features of loading from the crane rollers and the effect on the stress-strain state of crane beam elements in terms of formation of fatigue cracks in the upper compressed zone of the wall were highlighted. The main objective of the study is to search for the features of the crane beam construction of cranes with heavy operation mode, to search for methods of modernization of design features in order to prevent/minimize the development of fatigue cracks.Materials and methods. The research is based on long-term experience in the operation of crane beams of heavy and especially heavy operating modes of cranes, data from conclusions based on the results of surveys of building structures, conclusions on industrial safety of hazardous production facilities, scientific publications. Based on the design schemes of existing and actually operated crane beams of the metallurgical enterprise, a computational model of the structure under study was developed in the computational complex of strength analysis of structures by the method of finite element analysis.Results. The stress-strain state of crane beam structures of cranes with heavy and especially heavy operating modes is analyzed, the influence of the position of the crane roller on the condition of various parts of the crane beam structure: walls, belts and ribs is studied. The regularity in the work of structural elements is derived when the frequency of the transverse ribs of crane beams changes. Assumptions are made to solve the strength problem of the formation of unacceptable fatigue cracks in the upper compressed zone of the crane beam wall.Conclusions. Based on the results of numerical analysis of the stress-strain state of the crane beam construction model, data are presented indicating the previously unknown peculiarities of crane beams operation. A hypothesis is given for solving the strength problem of the formation of unacceptable fatigue cracks in the upper compressed zone of the crane beam wall.
Vestnik MGSU. 2024;19(6):878-891
878-891
Design of monolithic concrete foundation slabs with FRP reinforcement
Abstract
Introduction. Over the past decade, the share of concrete structures reinforced with composite polymer reinforcement (FRP) has increased, which is due, among other things, to the development of the regulatory and technical framework in this direction. The inherent features of FRP, largely determined by the properties of its components, which must be taken into account at all stages of construction and operation of the building, lead to some changes in the traditional approaches to the design of structures and the technology of their construction.Materials and methods. A review of domestic experience in the use of composite polymer reinforcement in the construction of monolithic concrete foundations is carried out. An example of design and construction solutions of a foundation plate is considered. On the basis of its analysis, the selection of reinforcement from FRP was carried out according to the results of calculations for the first and second groups of limit states.Results. Design features that should be taken into account when calculating foundation slabs made of concrete reinforced with FRP are indicated. The concrete example of a monolithic concrete foundation slab shows the effect of taking into account the actual mechanical characteristics of FRP on the results of strength and crack resistance calculations. The results of calculations carried out according to various editions of regulatory documents relevant for the period from 2014 to 2023 clearly demonstrate the development of the regulatory framework in terms of taking into account the FRP properties in reinforced concrete structures.Conclusions. With a rational approach to design processes, it is possible to develop projects of concrete foundation slabs on an elastic base using FRP that meet the requirements of regulatory documents on reliability. It is possible to completely exclude metal elements (fittings, products, embedded parts) in such structures.
Vestnik MGSU. 2024;19(6):892-905
892-905
Computational aerodynamic studies of the MIBC “Moscow-City” complex during sequential construction of buildings
Abstract
Introduction. Computational studies of aerodynamic interference of the MIBC “Moscow-City” complex with sequential construction of buildings, taking into account their chronological order are carried out. Previous studies only considered the designed buildings and structures, along with the surrounding actual and future development, without computational analysis of their impact on the already constructed buildings. The study demonstrates the importance of considering aerodynamic interference in numerical simulation. It draws conclusions on the mutual influence of high-rise buildings and identifies the wind attack angles that contribute to the maximum values of the average and pulsation components of the wind action.Materials and methods. Numerical simulation methods in the ANSYS Fluent software package were used to conduct computational analysis. Quasi-two-dimensional aerodynamic models of the building complex of MIBC “Moscow-City” were developed, verified and validated for the computational studies.Results. The paper presents the results of 256 design cases, including 13 design variants for the consecutive erection of buildings in the MIBC “Moscow-City” complex and 19 calculations of freestanding high-rise buildings. Each calculation was performed for eight wind attack directions. The paper provides the average and pulsation total aerodynamic forces and moments for each building of the complex, depending on the chronology of building construction. The radar charts of aerodynamic coefficients (average and pulsation) were used to determine the most dangerous wind directions. The number of constructed buildings in the MIBC “Moscow-City” complex was taken into account.Conclusions. Based on the example of the sequential construction of the MIBC “Moscow-City” complex, this study emphasizes the importance of considering aerodynamic interference in dense and changing urban environments for both new and existing buildings. Aerodynamic interference can result in both wind shielding effects and increased wind, which affects the mechanical safety of buildings and structures.
Vestnik MGSU. 2024;19(6):906-941
906-941
Quick-assembly units in steel frames of multi-storey buildings
Abstract
Introduction. In the conditions of steel construction development, it is relevant to create a nomenclature of standard unified products, assemblies and parts of steel frames, which will allow engineers to create projects of modern prefabricated buildings with less labour costs, and builders to implement them quickly and efficiently. The joints of the column junction in height and their coupling with the floor beams are considered. In these design solutions, the forces are transmitted by direct contact of the end surfaces of the connected elements, which avoids the execution of mounting welds and a large number of bolted connections. As a result, when using contact connections, the installation time and the cost of construction of the metal frame are reduced.Materials and methods. When considering contact problems, the Saint-Venant principle is not applicable, it is important to explore the immediate areas of the contact surfaces of the elements. The nodes were developed using the example of a typical frame of a five-storey building with cell sizes from 3 × 3 to 6 × 6 m with structural elements of specified sections.Results. The possible contact connections of the frame elements are presented, which allow assembly only by installing them on top of each other and finishing adjustment. Such connections, due to the work of the contact surfaces on the crumple, allow transmitting not only longitudinal forces, but also some of the bending moments.Conclusions. The proposed options for column joints and beam-to-column junctions are non-typical and not previously used in engineering practice. For the widespread use of such units in the practice of designing steel frames of multi-storey buildings, it is necessary to investigate their bearing capacity and deformability comprehensively. It is of interest to study the influence of the geometric parameters of the connecting elements on the stiffness of the nodes and on the stress-strain state of the frame as a whole. The present research will be conducted using computer software and experiment.
Vestnik MGSU. 2024;19(6):942-959
942-959
Modification of Rayleigh dissipation function for numerical simulation of internal damping in rod structures
Abstract
Introduction. The paper proposes a method of accounting for energy dissipation for the Timoshenko beam by constructing a damping matrix based on a modified Rayleigh function in the numerical solution of the problem. In this modification, the velocity of displacements is replaced by the velocities of linear and angular deformations. This approach allows us to take into account energy dissipation due to internal friction in the material when both its volume and shape change. The presented technique is promising in practical calculations of structures when shear stiffness has a significant impact on their stress-strain state.Materials and methods. Several proven methods of energy dissipation accounting are considered, including those that make it possible to take into account the energy loss of a moving structure during friction with the external environment (external damping) and dissipation due to friction in the material of the structure deformed in motion (internal damping). Methods for determining the damping coefficients for each of them are presented. The finite element method is used to calculate rod systems. Damping matrices are derived from the condition of stationarity of the total energy of deformation of a mechanical system in motion, including linear and angular deformation rates.Results. Damping matrices proportional to strain rates obtained on the basis of the modified dissipative Rayleigh function are given. A method for determining the damping coefficient taking into account the rates of angular deformation is proposed.Conclusions. The damping matrices presented in the paper describe the energy dissipation during vibrations of mechanical systems due to internal friction in the material. The internal damping matrix was obtained taking into account the influence of linear and angular deformation rates to simulate the dynamic behaviour of short bending structural elements, the deformation of which is described using the Timoshenko model. The performed dimensional check additionally confirms the correctness of the damping matrix construction. Moreover, the dimension of the proposed shear damping coefficient is the same as that of the widely used viscosity coefficient.
Vestnik MGSU. 2024;19(6):960-970
960-970
Construction material engineering
Influence of climate and external plaster on the humidity conditions of masonry walls
Abstract
Introduction. The study was carried out to determine the possible causes of damage to the finishing plaster coverings on the facades of historical stone buildings, built in St. Petersburg before 1917, as a result of their humidification and subsequent frost destruction.Materials and methods. The mechanism of humidification of a homogeneous wall structure plastered on both sides due to the moisture transfer from the room to the environment through the wall thickness due to the difference in partial pressures of water vapour from inside and outside the room during the cold season is studied. The paper provides the graphs of the distribution of the actual and maximum partial pressures of water vapour over the thickness of the wall structure, depending on the type of plaster covering, for two calculated cases — for the conditions of the coldest month and the coldest five-day period in St. Petersburg.Results. It is revealed that for the conditions of the coldest month in St. Petersburg, the actual partial pressure of water vapour in the thickness of the wall structure under consideration does not exceed the maximum, which indicates the absence of conditions for moisture condensation in the thickness of the wall envelope. However, as the vapour permeability of the external plaster decreases, the curves of the distribution of the actual and maximum partial pressures converge at the interface of the stone base and the plaster covering. For the conditions of the coldest five-day period, the actual partial pressure of water vapour already at a distance of 135 mm from the inner surface exceeds the maximum partial pressure, which indicates a high risk of moisture condensation, and this risk is the higher the less vapour permeable the plaster covering is.Conclusions. It is proven that when the coldest outdoor temperatures are established, there is a high probability of condensation of water vapour in the thickness of the wall structure under consideration. The highest risk of freezing of the condensable moisture will be observed at the interface of stone base with the external plaster. Freezing of moisture in cracks and voids in the contact zone of the stone base and the plaster covering can lead to water trapping, the occurrence of significant internal stresses in the finishing layer and, as a result, to its gradual damage, up to the loss of individual fragments of plaster.
Vestnik MGSU. 2024;19(6):971-981
971-981
Analysis of strength and thermal conductivity characteristics of layered beams consisting of solid wood and thermal insulation material
Abstract
Introduction. The paper describes experimental and theoretical work on the study of the characteristics of a layered building material — thermal timber, consisting of solid wood and layers of thermal insulation. Such materials are used for construction of lightly built wooden houses of private sector and low-rise houses. The peculiarities of this type of materials is that simultaneously with the construction material — wood beam contains a layer or layers of insulation, which allows to reduce the stage of insulation of the house during its construction. Strong wood and absolutely nothing capable of carrying insulation together can give a material whose characteristics are fundamentally different from both the first and the second.Materials and methods. The influence of the number and thickness of layers of thermal insulation and wood on the strength and thermal insulation characteristics of the resulting timber is considered. Knowing the regularities of changing characteristics from the number of layers, it becomes possible to choose a rational system of alternation of wood and insulation layers. Experimental studies of beams with different number and thickness of thermal insulation and power layers were carried out, the total thickness of both power and thermal insulation layers in each beam were the same, but the sequence of laying was changed.Results. The results of the experimental study of the bending strength of the thermal timber and the calculated study of its thermal insulation characteristics are shown. Dependences of maximum loads for beams with different number of wood/insulation layers were experimentally obtained.Conclusions. As a result of the experiments it turned out that the linear bending theory cannot accurately describe the behaviour of the layered material — the withstand load grew with the increase in the number of layers.
Vestnik MGSU. 2024;19(6):982-990
982-990
Hydraulics. Geotechnique. Hydrotechnical construction
Analytical determination of the stress-strain state of soil mass during tunnelling
Abstract
Introduction. One of the effective approaches to assessing the impact of tunnel construction works involves a comprehensive approach to problem-solving, including determination of the face-support pressure to ensure the stability of the tunnel face and assessment of additional surface movements that occur during tunnel construction. This approach is justified by the fact that actual displacements can be close to predicted ones when the optimal face-support pressure is selected and there is no face loss of soil, which could lead to unforeseen deformations. However, it should be noted that the method for calculating pressure presented in the current standard is a preliminary forecast and requires constant adjustment of the pressure during tunnel construction works.Materials and methods. In this work, the authors adapted Melan’s problem formulation with a horizontal load parallel to the surface to assess the change in the stress-strain state of the soil mass before tunnel face excavation due to the application of the face-support pressure. The problem formulation corresponds to the stage of work preparation before excavation of the soil for the installation of a precast concrete lining ring into its design position.Results. Based on the analytical equations formulated in the MathCAD software environment, isopoles of vertical and horizontal stresses, and vertical deformations were created. The obtained isopoles were compared with isopoles generated in the Plaxis 2D software using similar parameters to validate the results. Additionally, isopoles of the soil mass under the influence of the face-support pressure, considering self-weight stresses, were obtained to establish a more realistic stress-strain state of the mass in which a tunnel is being constructed.Conclusions. The analysis of the research results has shown that the isopoles are quantitatively and qualitatively similar to each other. The method proposed by the authors can be adapted with appropriate modifications to adjust the face-support pressure during construction, which is necessary both to ensure the stability of the tunnel face during construction and to minimize the impact of the face-support pressure on the ground surface.
Vestnik MGSU. 2024;19(6):991-1005
991-1005
Technology and organization of construction. Economics and management in construction
Informatization of construction production organization and operational management
Abstract
Introduction. The question of the dependence of the intensity of the operational management of construction production on the organization of interaction between key production executors, services and management of a construction enterprise is considered.Materials and methods. The method of coordinating solutions of current production, support and management tasks based on a unified structure of algorithms of technological processes in the design elevations of the structure, the organization of production activities at the construction site and operational management is presented. The definition of the intensity of operational management as a measure of the effectiveness of the organization of interaction between production, services and management of the enterprise is proposed.Results. The form of analytical continuous, piecewise linear dependence of the intensity of the operational management of the construction process on the coordination of the values of the parameters of the organization of construction production is obtained: its provision with resources, as well as compliance with the requirements of construction control in a changing production situation. The formula for the intensity of operational management of the implementation of the assembly and laying technological process in specific design elevations of the structure within the established timeframes was obtained. The parameters of the mathematical model of the intensity of operational control, as well as the digital interface for its use, are obtained. Boundary values for the variables of the domain of determination of the permissible values of the parameters of the organization of technological processes, providing measures, material supply, as well as a relative scale for the intensity of operational management are obtained. Graphs of changes in the intensity of operational control during the execution of the technical process in the local design elevations of the structure were obtained and analyzed.Conclusions. The conclusion is made about the formation of a unified information environment for the organization of construction production during construction and operational management through compatible algorithms, data structures and AWS interfaces based on a mathematical model that coordinates the algorithms for solving production problems and communication of key performers in terms of the parameters of the organization of construction production and operational management.
Vestnik MGSU. 2024;19(6):1006-1015
1006-1015
Blockchain transactions as a promising mechanism to ensure sustainable development of the construction complex under sanctions (by the example of the Russian economy)
Abstract
Introduction. Restrictions imposed by Western countries on the access of the Russian financial system to international clearing systems significantly complicate the development of economic sectors that are deeply integrated into international supply chains. Among them, it is necessary to single out the construction industry, which acts as a “locomotive” for the development of many other types of economic activity. This paper is devoted to the review of emerging macroeconomic effects in the context of leveling the risks of the growth dynamics of the construction industry of the Russian Federation within the framework of the transition of the national payment system to blockchain (DLT) in the context of solving the issue of import substitution. The subject of the study is the features of the prospects for sustainable development of the Russian economy in the context of adjusting the import of construction materials.Materials and methods. The tools of building a system of recursive equations estimating macroeconomic externalities in the process of simulation modelling of blockchain use in the system of ensuring sustainable settlements with foreign counterparties, as well as correlation and regression analysis, which forms the basis for identifying the impact of the Russian construction industry on the prospects for GDP growth were applied.Results. The short-term potential of possible slowdown of Russia’s GDP growth (–0.45 % per year) as part of the localization of import supplies of building materials. It is substantiated that the risks of limiting the supply of building materials can be ensured through the introduction of blockchain technologies into the system of cross-border payments of the Russian Federation, which form a new basis for the movement of cash flows.Conclusions. The value of the obtained research results consists in the identified and empirically substantiated risks of slowing down the development of the construction industry and the national economy of the Russian Federation as a whole within the framework of possible localization of supplies of building materials from abroad as a result of sanctions pressure on financial markets. It is substantiated that the creation of regional blockchain platforms on a global scale can act as a tool for leveling risks, providing the possibility of stability and independence of the formation of transnational supply chains from global clearing services.
Vestnik MGSU. 2024;19(6):1016-1030
1016-1030
Environmentally friendly construction technologies selection criteria in the Arctic
Abstract
Introduction. The paper substantiates the relevance of creating and improving digital tools for complex scientific research and development work based on the information model of a construction object at all stages of the life cycle. The research focuses on environmentally safe (green) construction in the northern and Arctic regions. The purpose of the study is to substantiate a set of criteria for “green” for the northern and Arctic regions of the Russian Federation on the basis of logically interrelated models: a design model, a full-scale model, mathematical models and a digital twin model. The main criteria include energy efficiency and environmental safety of buildings.Materials and methods. The objects of the study are two twin buildings designed and built according to the programme of scientific research in the Republic of Karelia and the Murmansk region. The objects are identical, but the conditions of their functioning are different. The methodology of complex scientific research for each stage of the life cycle of objects is proposed. The methods of comparative analysis and the method of expert assessments were used, as well as the methods presented in the normative and technical documents of the technical regulation system of the Russian Federation related to the technological aspects of construction.Results. Four groups of basic construction criteria for the northern and Arctic regions of the Russian Federation are defined: external environment; internal environment; materials and technologies; energy efficiency. The Research Information Model (RIM) was developed as a tool for comprehensive scientific research in the field of construction technologies in the northern and Arctic regions. The practical implementation of the results of the study at the two above-mentioned facilities, including digital monitoring of the condition of the facilities for two years (2021–2023), is considered. Prospects for the continuation of the research are determined.Conclusions. The necessity of the development is justified and the expediency of using the developed information model of research is confirmed by the example of two constructed objects. The experience of using the main blocks of the model and digital monitoring of the condition of objects for two years has confirmed the expediency of using information modelling and continuing research to improve construction technologies in the northern and Arctic regions.
Vestnik MGSU. 2024;19(6):1031-1046
1031-1046