Vol 19, No 3 (2024)
Architecture and urban planning. Reconstruction and refurbishment
Method of calculation of geometrical parameters of building atrium structures considering the comfort of temperature and air regime
Abstract
Introduction. The influence of atrium on temperature stratification under indoor natural ventilation of the teaching-laboratory building of the Moscow State University of Civil Engineering (MGSU) with the help of full-scale experiments is considered. Based on this, the aim of the research is to develop a new method of calculating the optimal geometric parameters of a building atrium considering the comfort of its temperature-air regime by solving the developed basic airflow equations in combination with mathematical modelling methods. The formula for determining the air flow rate for natural ventilation in atriums, analyzing and designing a natural ventilation system in a building with an atrium with more than two ventilation outlets was derived. Based on the results obtained, a conclusion is made about the optimal area of exhaust and supply openings in an atrium building at different heights. These data may have practical application in the design of buildings with atriums.Materials and methods. Semi-empirical research methods were used. Simple linear regression methods were carried out to establish a correlation between the measured variables air temperature and building construction height in an atrium with specific conditions to determine the temperature at any height.Results. The formula for calculating the optimal area of inlet and outlet openings in connection with the atrium height and their influence on the thermal characteristics of the structures of buildings with atriums was developed.Conclusions. The results of the research make it possible to quickly and accurately determine the geometric parameters to ensure the reduction of air temperature in buildings with atriums. This plays an important role in the initial design phase.
Vestnik MGSU. 2024;19(3):349-357
349-357
Construction system design and layout planning. Construction mechanics. Bases and foundations, underground structures
The formulation of sound transmission problems through the boundaries of three-dimensional media and through plates
Abstract
Introduction. Modern physical models for calculating the propagation of plane longitudinal waves through media boundaries, based on the conditions of continuity of sound pressure and vibrational velocity, are implemented only with normal wave incidence. In all directions of wave propagation other than normal, the continuity conditions are not observed, which does not allow to obtain the correct formulas for the coefficients of reflection and transmission of waves.Materials and methods. In the proposed formulation of the problem, the physical model of the wave propagation medium consists of pieces of wave rays, tightly, without breaks and mutual penetrations, occupying its entire space (as it clearly happens with waves on the surface of water). A method for determining the volumes of these pieces is given. Their masses are approximated by material points having effective values of vibrational wave velocities. The passage of a plane harmonic wave through a plane boundary of media is described by the equations of conservation of kinetic energy and conservation of the amount of motion. The solution of these equations gives the correct formulas for the coefficients of reflection and refraction of waves in terms of vibrational velocity at any angles of their propagation.Results. The proposed formulation of the problem of wave propagation through the boundary of continuous semi-infinite media is suitable for solving the problems of sound propagation through layers and, in particular, through plates. The problem of sound propagation through a plate separating the air medium is fundamental in the sections of architectural and technical acoustics, since applied theories of sound insulation of walls and ceilings of buildings and vehicles enclosing premises are based on it.Conclusions. The conservation equations, up to the boundary frequency of the wave coincidence, will include the effective value of the vibrational velocity in the incident wave, the angle of wave propagation, the values of the mass of a discrete body represented by the surface density of the plate, the reduced masses of the pieces of the medium and unknown coefficients of reflection and passage of the vibrational velocity. At frequencies above the boundary, the mass of the discrete body changes to the reduced mass of the plate. The solution of the system of conservation equations gives the correct formulas for the coefficients of sound transmission and reflection and the correct formulas for sound insulation, in accordance with changes in the physical models of wave propagation in different frequency ranges.
Vestnik MGSU. 2024;19(3):358-366
358-366
Analytical method for determining the stress-strain state of modular buildings
Abstract
Introduction. Active introduction of modular buildings into the practice of modern construction causes the necessity to develop methods of their calculation. At the same time, there are no specialized guidelines for the design of modular buildings. It is impossible to manage only with numerical methods of calculation for forming design recommendations. Therefore, the creation of an analytical method of calculation of modular buildings is an important area of research. The question of determination of forces in elements of modular buildings with bearing columns and rigid intramodular connections is considered.Materials and methods. The determination of forces in the elements of modular buildings from vertical loads can be carried out with high accuracy using well-known formulas of building mechanics. The main difficulty is the determination of dynamic effects (wind pulsation and seismic load). It is proposed to use a cantilever construction scheme with the decomposition of masses at the floor level. As a result of calculations, a set of inertial forces is formed from pulsation and seismic action. Modular programme was written to simplify the calculations. The programme is convenient for making preliminary and variant calculations and research of modular building structures.Results. The presented analytical method for determining the forces in the elements of modular buildings shows good convergence of the results with the finite element method. On a concrete example, it is shown that there is practically no discrepancy in determination of forces from vertical loads. The discrepancy from the combined effect of the static and pulsation components is 4.2–16.6 % for bending moments and 1.3–6 % for longitudinal forces. The discrepancy in determining the forces from the seismic load is within the range of 5–10 % for both bending moments and longitudinal forces.Conclusions. The method is convenient for application at the stage of qualitative assessment of design solutions, variant calculations and search for rational design solutions of modular buildings.
Vestnik MGSU. 2024;19(3):367-376
367-376
Formula for two-sided estimation of the fundamental frequency of oscillations of a lattice truss
Abstract
Introduction. One of the main tasks of the theory of oscillations of building structures is the determination of the fundamental frequency of natural oscillations. Analytical solutions are rare here and, as a rule, are based on approximate estimates of the first frequency from above (Rayleigh’s method) or from below (Dunkerley’s estimate). Most often, the problem of natural oscillations is solved numerically by the finite element method using specialized packages. In this paper, the task is to derive analytical estimates of the dependence of the first oscillation frequency of a lattice truss on the number of panels, the geometric characteristics of the structure, and the parameters of the elastic properties of the material.Materials and methods. A flat statically determinable lattice is supported by its base on struts. The angular support is a fixed joint. Calculation of forces in structural elements is performed by cutting out nodes using standard operators of the Maple symbolic mathematics system. The rigidity of the truss is found by the Maxwell – Mohr formula. The mass of the truss is distributed uniformly over its nodes. Mass oscillations occur vertically. By generalizing a series of solutions for trusses with a successively increasing order to an arbitrary number of panels, the desired formulas are derived by induction.Results. A case of kinematic variability of the proposed truss scheme was noticed. Formulas for the first frequency are obtained by the Dunkerley and Rayleigh method. The two analytical solutions are compared with the numerical solution obtained for the entire frequency spectrum. Spectral constants and resonant safety regions were discovered in the spectra of a family of regular trusses.Conclusions. The two-sided method for estimating the first frequency is applicable to solving problems on regular constructions, where the final formula includes the order of regularity as a parameter. For the construction under consideration, the error of the Rayleigh method is comparable to the error of the Dunkerley method.
Vestnik MGSU. 2024;19(3):377-386
377-386
Development of a constructive solution of wood columns and crossbars interfaces on metal overlays and screws
Abstract
Introduction. The paper discusses the advantages and features of the main existing methods of connecting wooden columns and crossbars.Materials and methods. It was proposed to increase the load-bearing capacity and reduce the deformability of joints by modifying the joints with the introduction of epoxy resin between the screw and the wood and between the overlay and the end of the wooden element to which it is attached and modifying the design of the overlays.Results. As a result, a constructive solution for connecting wooden columns and crossbars was developed, which has increased reliability compared to the studied connections and is free of their disadvantages. This result was achieved due to the presence of an adhesive layer between the screw and the wood, as well as between the overlay and the wooden element, the making of notches on the sides of the overlays attached to the wooden elements, the increased length of the screws screwed into the overlay with a groove, compared to the length of the screws screwed into an overlay with a tenon, placement of holes for screws at an angle of 90° to the surface of the overlay into which the screws are screwed.Conclusions. An urgent issue is the development of constructive solutions for connections of wooden elements, in particular the interfaces of columns and crossbars. The paper discusses the advantages and features of the main existing methods of connecting wooden columns and crossbars.
Vestnik MGSU. 2024;19(3):387-393
387-393
Construction material engineering
Determination of durability of building ceramics
Abstract
Introduction. Large-scale field studies of the destruction of brickwork carried out by the author in many regions of the world showed that the approach to the research of the durability of building ceramics based on the strength parameter and the frost resistance parameter are not indicative. These parameters do not make it possible to obtain a temporary value of the durability of the material, but are just the basis for an expert assessment.Materials and methods. This paper proves the scientific hypothesis put forward by the author that the destruction of brick material in the brickwork of enclosing structures occurs under the influence of chemical corrosion processes. The process of chemical corrosion is described, the results of thermodynamic calculations of chemical processes are briefly presented. A brief description of the methods of studying the durability of the building ceramics material, which have now received the status of standards, is given.Results. The results of laboratory studies of the process of chemical destruction of the building ceramics material, as well as calculations of the durability of the building ceramics material performed on the basis of the developed method of calculating the durability of the material are presented.Conclusions. Based on the developed theoretical justification and laboratory studies of the process of chemical destruction of the wall ceramics material, it is concluded that the created research methodology and calculation method allow to determine the durability of the material at any stage of its operation.
Vestnik MGSU. 2024;19(3):394-402
394-402
Safety of Construction and Urban Economy
Greening negative factors in the activities of enterprises and organizations
Abstract
Introduction. Environmental certification in accordance with ISO 14001 and EMAS makes it possible to understand and assess the impact of economic activities on ecosystems, as well as to set environmental goals and objectives for improving the activities of enterprises and organizations. The effects of the EMS (environmental management and audit scheme) depend on how companies decide to use them after certification. In this regard, the authors investigate the organizational climate issues associated with the use of ISO 14000 and EMAS series standards to improve the environmental efficiency of companies.Materials and methods. The methodology is presented in the form of an environmental safety model related to the enterprises and organizations, including environmental audit, environmental standardization and environmental assessment of compliance with various environmental requirements at different levels of organization of enterprises’ activities. The object of research is the international environmental standards of the ISO 14000 and EMAS series. The subject of the study is the environmental safety of negative factors in the activities of enterprises and organizations. The concept of the necessity of greening personnel training and a positively environmentally oriented organizational climate in enterprises and organizations is proposed.Results. The implementation of EMS does not always lead to an improvement in the environmental performance of companies. Some companies focus on formal criteria without taking into account real environmental problems. In addition, environmental indicators can take the form of coefficients and can be improved with unchanged or even worsened environmental impact. The organizational climate is important for the realization of EMS goals, especially the attitude of employees to the environment and environmental values. Despite limitations, EMS, environmental audit and ISO 14000 principles can help companies reduce their negative impact on the environment and increase their competitiveness, as well as make more informed choices when planning their activities.Conclusions. The importance of creating an organizational climate for the successful greening of negative factors in the activities of enterprises and organizations is emphasized. There is also a need for a more accurate assessment of the effectiveness of environmental measures when formulating environmental standards and assessing compliance with their implementation.
Vestnik MGSU. 2024;19(3):403-414
403-414
Hydraulics. Geotechnique. Hydrotechnical construction
Experimental determination of the parameters of the methodology for investigating the frost strength bond of soil and foundation material
Abstract
Introduction. Freezing strength is a strength characteristic of frozen soils that describes their mechanical interaction with underground structures of buildings and structures. This characteristic is used in determining the bearing capacity of piles located in the zone of permafrost, and in assessing the pull-out effect of the tangential forces of frost heaving of seasonally frozen soils. The strength of freezing is determined by laboratory experiments, through the implementation of a shift of frozen soil relative to the material being tested. There are several different methods for determining the freezing strength, but all of them have some disadvantages: some are cumbersome and difficult to carry out; in others it is impossible to simulate all types of soil freezing conditions.Materials and methods. To study the freezing strength of glass-reinforced plastic with a frozen soil specimen, the Department of Geotechnics of SPbGASU proposed a new method for determining the freezing strength of soil and underground structures, which makes it possible to reduce the labour intensity of testing, minimize the additional impact on the tested soils during their preparation, and also take into account the peculiarities of soil freezing around the foundation. However, like any new method, it has a number of uncertainties. In the framework of this study, the optimal parameters of the method were experimentally established: the ratio of the diameter of the form to its height, the design of the support, as well as the method of insulation during freezing.Results. The shape of the tested specimen has a significant influence on the final value of the freezing strength, the construction of the support and the method of insulation of the specimens influence the obtained result during the test. The best solutions are: the use of a ring-shaped support that prevents mould movement and does not prevent ground movement, and the use of insulation by immersing the specimens in the insulation rather than wrapping them in it.Conclusions. A complete method for determining the frost strength bond of soil with underground structure material is presented, the reliability of the results obtained is superior to that of the data obtained by the GOST method, as shown by the lower value of the coefficient of variation within the results of the control sample of specimens.
Vestnik MGSU. 2024;19(3):415-425
415-425
Engineering systems in construction
Adsorption of phenol on activated carbon obtained from date palm branches
Abstract
Introduction. Phenols are one of the main organic components present in the effluents of many industrial enterprises. However, the discharge of wastewater containing phenol is a priority due to its high toxicity to humans and animals, even at low concentrations. Activated carbon (AC) adsorption, which is one of the advanced purification processes, is widely used to purify water pollutants and the production of activated carbon from several carbon by-products of agriculture was also reported. In this regard, the purpose of this research was to study the adsorption of phenol on activated carbon based on date palm branches (DPB-AC) as a low-cost adsorbent.Materials and methods. DPB was used as a raw material for the production of AC by chemical activation of H3PO4. Adsorption experiments were carried out in batches. The kinetics and isotherms of adsorption were also investigated.Results. DPB-AC was obtained by chemical activation of date palm branches using H3PO4 (600 ℃, 60 min), and the specimen was designated as (DPB-AC-H3PO4). The results showed an AC yield of 52.7 %. The maximum efficiency of phenol adsorption was achieved at pH 7. In addition, phenol adsorption was well described by the kinetics of the pseudo second order with K2 = 0.0503 g/(mg·min). The phenol adsorption isotherm model followed the Langmuir model, where R2 was 0.9215 and KL = 0.0161 l/mg at 180-equilibrium time. The maximum adsorption capacity of phenol was 77.52 mg/g (mg of phenol absorbed/g of DPB-AC-H3PO4), which is a high value compared to many other results presented in the literature.Conclusions. In general, the results indicate that AC obtained from date palm branches can be a promising material for wastewater treatment, as well as an effective means to solve environmental pollution problems.
Vestnik MGSU. 2024;19(3):426-435
426-435
Technology and organization of construction. Economics and management in construction
Using Building Information Modelling (BIM) by studying building orientation during design to achieve more sustainable buildings
Abstract
Introduction. Energy is one of the most important issues that attract the attention of the whole world, and this in turn is reflected in the increase in energy consumption in residential and industrial buildings Therefore, the process of assessing the efficiency and quality of interior spaces is an important step from which the process of developing and upgrading these spaces begins to reach a sustainable model from an environmental, economic and social point of view.Materials and methods. The research aims to study the distribution patterns of residential divisions and their reflection on the energy of a residential suburb consisting of twenty residential buildings in Tartous Governorate, through the development of a software tool using Dynamo, which is one of the visual programming methods used in (BIM) using a programming language (Python) with the addition of studying heating and air conditioning loads for current orientation with comparison with loads after directing the building at different angles in order to reduce consumption and benefit from solar radiation sources through Revit. An analytical approach was used, through the analysis and extrapolation of the literature and references related to the study, in addition to the deductive approach by deducing problems in the current situation and providing suggestions for solutions that can be followed in the management and analysis of energy.Results. The BIM approach contributed to the study of the building orientation and its reflection on thermal loads, taking into account all the factors causing this load, which can be adjusted according to any requirements or code.Conclusions. Studying the building orientation during the design stage contributes to reducing the total annual heat load by more than 20 %, and this percentage varies according to the way buildings are assembled.
Vestnik MGSU. 2024;19(3):436-455
436-455
Life cycle management of capital construction object with minimization of atmospheric air pollution
Abstract
Introduction. The existing approaches to management decision-making in construction production give the opportunity to select options only for a certain stage of the capital construction object life cycle (LC CCO), not considering their effectiveness throughout the whole LC. To eliminate this disadvantage, the authors propose a system of information support for the LC CСO management, taking into account the minimization of atmospheric air dust pollution during the implementation of decisions.Materials and methods. Within the framework of a systematic approach to the LC CCO management, the correct criteria choice is of crucial importance, using which an optimal decision can be made. On the other hand, the need to ensure the effectiveness of managerial decisions throughout the LC CCO involves the development of a system that allows to predict the managed object behavior throughout its entire life cycle already in the initial stages. Since the occurrence of various events (situations) during the LC CCO is random, the determination of the probability of occurrence of these or those events is of great importance. Technical means for monitoring atmospheric air pollution by dust particles PM2.5 and PM10 are presented.Results. To take into account other decision-making criteria, besides technical and economic indicators, the experimentally obtained reduced values of dust concentration in atmospheric air are proposed. For this purpose, the sources of such pollution in all the LC CCO stages are systematized. Based on the developed life cycle model, expressions for determining the probability of events occurrence during the LC CCO are obtained. This stochastic model allows you to predict the state of the control object when implementing a particular solution. The application of the proposed methodology made it possible to determine the fine dust concentration and the probability of exceeding the maximum permissible concentration in some types of work to calculate the effectiveness of the considered management decisions.Conclusions. An information support system was built, which, unlike the applied methods, makes it possible to make decisions on the LC CCO management, not only taking into account the technical and economic efficiency of the compared options, but also the degree of atmospheric air dust pollution. In addition, the developed information support allows you to take into account the fact that certain events occurrence is random during the LC CCO with the determination of their occurrence probability.
Vestnik MGSU. 2024;19(3):456-468
456-468
Determination of element weight for the purpose of prioritization of intersection collision correction
Abstract
Introduction. It is proposed to optimize the time of highly qualified engineers working with a building information model (BIM) during the correction of intersection collisions due to mathematical determination of importance of an element in intersection collisions.Materials and methods. The method of frequency analysis is taken as a basis, using the quality coefficient of BIM. The quality coefficient of BIM is determined based on the data about the BIM itself: number of elements, objects and collisions. The calculated coefficients influence the results obtained using the frequency analysis method. As a result, unique values of importance weights for BIM elements are obtained.Results. The weights of the elements found during the study are sorted in descending order, the first 20 % of the elements with the highest weight are the load-bearing structures, indicating that fixing collisions involving them should be a priority. The priority of correcting collisions involving other non-bearing elements of the BIM can be determined by assigning weights to them based on the elements involved in collisions.Conclusions. The results of the study will help to assign priority to the intersection collisions found. This, in turn, will allow highly qualified engineers to fix the most important intersection collisions in a priority order, thereby using their time more efficiently. The resulting element weights can be applied by exporting the collisions found in the project to a tabular data format. Using tabular editors and pivot table functions, you can assign weights to elements and sort collisions.
Vestnik MGSU. 2024;19(3):469-477
469-477