Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.5
Yulia Kustikova, E. V. Pankova
Introduction. Nowadays, improving the quality of repair-construction works is an important complex problem, insufficient attention to which inevitably leads to their increasing cost, increasing operational costs, increasing the number of current and overhaul repairs, as well as reducing the time between repairs, worsening the quality of life of consumers. In the worst cases, poor quality of repair and construction works can lead to the accidents, become a source of threat to life and health, leading to accidents. The quality of work — is the main purpose of using the technological card; this standardized organizational and technological document contains detailed instructions for the working staff, allowing to understand all the processes to be carried out during the project as well as to evaluate the resources necessary for this. The process map contains a set of measures for the organisation of work with the most efficient use of modern means of mechanisation, technological equipment, tools and fixtures. This document includes the most progressive and rational methods of construction works technology facilitating reduction of time and improvement of work quality and reduction of their cost. The technological card ensures not only economical and high quality, but also safe execution of works, as it contains regulatory requirements and safety rules. Materials and methods. The task is to analyse flow charts for different types of work in major repairs with the identification of a list of shortcomings, errors and inaccuracies in drawing up flow charts. Results. Proposals for correcting basic data and parameters in the flow charts required for operational control of the technological process have been developed. Conclusions. A list of flow charts for different types of work during major repairs has been analysed; a list of shortcomings, errors and inaccuracies in drawing up flow charts that require adjustments has been identified.
{"title":"A flow chart as one of tools improving the quality of repair and construction work","authors":"Yulia Kustikova, E. V. Pankova","doi":"10.22227/2305-5502.2023.1.5","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.5","url":null,"abstract":"Introduction. Nowadays, improving the quality of repair-construction works is an important complex problem, insufficient attention to which inevitably leads to their increasing cost, increasing operational costs, increasing the number of current and overhaul repairs, as well as reducing the time between repairs, worsening the quality of life of consumers. In the worst cases, poor quality of repair and construction works can lead to the accidents, become a source of threat to life and health, leading to accidents. The quality of work — is the main purpose of using the technological card; this standardized organizational and technological document contains detailed instructions for the working staff, allowing to understand all the processes to be carried out during the project as well as to evaluate the resources necessary for this. The process map contains a set of measures for the organisation of work with the most efficient use of modern means of mechanisation, technological equipment, tools and fixtures. This document includes the most progressive and rational methods of construction works technology facilitating reduction of time and improvement of work quality and reduction of their cost. The technological card ensures not only economical and high quality, but also safe execution of works, as it contains regulatory requirements and safety rules. Materials and methods. The task is to analyse flow charts for different types of work in major repairs with the identification of a list of shortcomings, errors and inaccuracies in drawing up flow charts. Results. Proposals for correcting basic data and parameters in the flow charts required for operational control of the technological process have been developed. Conclusions. A list of flow charts for different types of work during major repairs has been analysed; a list of shortcomings, errors and inaccuracies in drawing up flow charts that require adjustments has been identified.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82435607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.6
R. Petrosyan
Introduction. Modern methods of executing total building renovation are based on the principles of flow and scientific methods of labour organisation, developed with due regard for the specific features of certain types of repair and construction works technologies. The following labour-intensiveness and duration of work, material-intensiveness, cost and production cost of constructions are considered as the main indicators of work production technology in the course of overhaul repair. Each of these indicators has corresponding reserves, which are identified and used to improve the manufacturability of production of each type of work, as well as on the building as a whole. Materials and methods. The article is based on the method of assessing the effectiveness of various options to reduce the duration of work, which directly affects the change in technological parameters. A ranking among contractors has been carried out to identify the reserves for increasing labour productivity, as well as to identify bona fide contractors for customers. Results. The developed methodology of evaluation of manufacturability of overhaul works allows contractors to justify for customers the proposals on reduction of terms and cost of overhaul works. The use of the developed organizational and technological mechanism in practice of interaction of all participants of capital repair process will allow not only to achieve the highest indicators, but also will serve as a basis for actualization of normative documents on total building renovation. Conclusions. The method of efficiency estimation of different variants of work time reduction and related changes of technological parameters according to Wald, Savage and Hurwitz criteria allowed to establish the most preferable construction-technological solution. The developed rating assessment of contractors will, on the basis of achieved results, enable to reveal reserves of increasing labour productivity in the course of repair-construction works and to encourage these organizations to be more preferable in carrying out competitive procedures of selecting contractors by the customer. The identified reserves of reducing the duration of overhaul works are used as a basis for the formation of measures to improve the manufacturability of works.
{"title":"Formation of an organisational and technological mechanism to improve the manufacturability of works in total building renovation","authors":"R. Petrosyan","doi":"10.22227/2305-5502.2023.1.6","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.6","url":null,"abstract":"Introduction. Modern methods of executing total building renovation are based on the principles of flow and scientific methods of labour organisation, developed with due regard for the specific features of certain types of repair and construction works technologies. The following labour-intensiveness and duration of work, material-intensiveness, cost and production cost of constructions are considered as the main indicators of work production technology in the course of overhaul repair. Each of these indicators has corresponding reserves, which are identified and used to improve the manufacturability of production of each type of work, as well as on the building as a whole. Materials and methods. The article is based on the method of assessing the effectiveness of various options to reduce the duration of work, which directly affects the change in technological parameters. A ranking among contractors has been carried out to identify the reserves for increasing labour productivity, as well as to identify bona fide contractors for customers. Results. The developed methodology of evaluation of manufacturability of overhaul works allows contractors to justify for customers the proposals on reduction of terms and cost of overhaul works. The use of the developed organizational and technological mechanism in practice of interaction of all participants of capital repair process will allow not only to achieve the highest indicators, but also will serve as a basis for actualization of normative documents on total building renovation. Conclusions. The method of efficiency estimation of different variants of work time reduction and related changes of technological parameters according to Wald, Savage and Hurwitz criteria allowed to establish the most preferable construction-technological solution. The developed rating assessment of contractors will, on the basis of achieved results, enable to reveal reserves of increasing labour productivity in the course of repair-construction works and to encourage these organizations to be more preferable in carrying out competitive procedures of selecting contractors by the customer. The identified reserves of reducing the duration of overhaul works are used as a basis for the formation of measures to improve the manufacturability of works.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86668779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.2
Youssef R. Hamaty, A. Tusnin
Introduction. As a building construction material, steel is widely used because of its high mechanical characteristics. Steel load-bearing structures of multi-storey buildings are a system formed by columns, beams, floor slabs and braces. The frame of a multi-storey building has a large number of elements and their connections. Errors in the fabrication, installation and operation of steel frames of multi-storey buildings can lead to a reduction in the load-bearing capacity of structures compared to the design. Deviations from the design position occur because of violations of the technical operatin.rules of the buildings beyond the permissible limits, design errors, imperfect standards and poor quality of work during the fabrication and installation of structures. The current Russian standards do not take into account the impact of fabrication and installation errors on the work of multi-storey frames. The initial geometric defects in the structural system and its individual elements contribute to the difference in performance between the real construction and an idealized one. Materials and methods. The study of the effect of initial imperfections on the stress-strain state of the steel frame is important and relevant. Initial imperfections are taken into account either by applying an equivalent load to the idealized design scheme or by forming a geometrically distorted by imperfections design scheme. The analysis can be linear or geometrically non-linear. Results. The results of the study of braced steel framework performance in the presence of initial imperfections are presented. The effect of initial imperfections in the form of deflection of columns from the vertical is considered. The values of the initial imperfections are determined in accordance with the current RF standards. Conclusions. The results obtained have made it possible to propose a correction factor to the results of the calculation of frames with imperfections to the results of the calculation of an idealized frame.
{"title":"Operation of braced steel frameworks with regard to assembly and fabrication errors","authors":"Youssef R. Hamaty, A. Tusnin","doi":"10.22227/2305-5502.2023.1.2","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.2","url":null,"abstract":"Introduction. As a building construction material, steel is widely used because of its high mechanical characteristics. Steel load-bearing structures of multi-storey buildings are a system formed by columns, beams, floor slabs and braces. The frame of a multi-storey building has a large number of elements and their connections. Errors in the fabrication, installation and operation of steel frames of multi-storey buildings can lead to a reduction in the load-bearing capacity of structures compared to the design. Deviations from the design position occur because of violations of the technical operatin.rules of the buildings beyond the permissible limits, design errors, imperfect standards and poor quality of work during the fabrication and installation of structures. The current Russian standards do not take into account the impact of fabrication and installation errors on the work of multi-storey frames. The initial geometric defects in the structural system and its individual elements contribute to the difference in performance between the real construction and an idealized one. Materials and methods. The study of the effect of initial imperfections on the stress-strain state of the steel frame is important and relevant. Initial imperfections are taken into account either by applying an equivalent load to the idealized design scheme or by forming a geometrically distorted by imperfections design scheme. The analysis can be linear or geometrically non-linear. Results. The results of the study of braced steel framework performance in the presence of initial imperfections are presented. The effect of initial imperfections in the form of deflection of columns from the vertical is considered. The values of the initial imperfections are determined in accordance with the current RF standards. Conclusions. The results obtained have made it possible to propose a correction factor to the results of the calculation of frames with imperfections to the results of the calculation of an idealized frame.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77598563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.9
A. V. Vasileva
Introduction. Today, many university museums around the world are facing the need to revise the principles of their activities in order to fully integrate into the daily life of their educational institutions. The main functions for such museums are patriotic, image-building, educational, educational and career guidance. Modern challenges include attracting not only students and applicants, but also a wider audience. Challenges of introducing new technologies will make them more relevant to younger generation. However, without defining the main purpose of the museum’s existence, it is impossible to build a coherent path for its development. Purpose. To determine the basic principles of exhibition organisation and its placement in the structure of a university campus, depending on the nature of the museum and the image of the educational institution. Results. Using the example of museums of the world’s largest universities, the specifics of their location depending on specialisation, the correlation between the organization of space and the theme of the exhibition, the characteristics of exhibition equipment, the principles of placement of different types of expositions in the structure of campuses are determined. Conclusions. It has been found that when the university is image oriented towards history and traditions, the museums are located in historical buildings and have a more familiar spatial structure and principles exhibition organization. In the case of striving to demonstrate the innovative nature of the university, the priority is given to the placement in the most accessible and technologically advanced modern buildings. Exhibitions related to the current life of the university are housed in more light, versatile and democratic spaces. The latest trend is the active use of multimedia and interactivity.
{"title":"Modern principles of organisation of university museums and exhibition spaces","authors":"A. V. Vasileva","doi":"10.22227/2305-5502.2023.1.9","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.9","url":null,"abstract":"Introduction. Today, many university museums around the world are facing the need to revise the principles of their activities in order to fully integrate into the daily life of their educational institutions. The main functions for such museums are patriotic, image-building, educational, educational and career guidance. Modern challenges include attracting not only students and applicants, but also a wider audience. Challenges of introducing new technologies will make them more relevant to younger generation. However, without defining the main purpose of the museum’s existence, it is impossible to build a coherent path for its development. Purpose. To determine the basic principles of exhibition organisation and its placement in the structure of a university campus, depending on the nature of the museum and the image of the educational institution. Results. Using the example of museums of the world’s largest universities, the specifics of their location depending on specialisation, the correlation between the organization of space and the theme of the exhibition, the characteristics of exhibition equipment, the principles of placement of different types of expositions in the structure of campuses are determined. Conclusions. It has been found that when the university is image oriented towards history and traditions, the museums are located in historical buildings and have a more familiar spatial structure and principles exhibition organization. In the case of striving to demonstrate the innovative nature of the university, the priority is given to the placement in the most accessible and technologically advanced modern buildings. Exhibitions related to the current life of the university are housed in more light, versatile and democratic spaces. The latest trend is the active use of multimedia and interactivity.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78241213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.8
M. Slepnev, Nadeshda V. Mozgunova
Introduction. The article devoted to the relevant problem of optimizing the natural framework of the city on the basis of rational use of the territory of the settlement as a public green area. The approach, based on the modern tendencies of urbanization, ecological utility, social benefits and rational use of territories. One of the important elements of the optimization of the ecological environment is the greening of the city space. At present, maintaining the balance of urbanized areas is a priority because with the growth and development of cities, the environment is becoming more and more aggressive. Also, with the increase in the number of residents, the recreational load increases, and due to the high concentration of emissions from motor vehicles and industrial enterprises, the state of urban natural systems is changing, which leads to a deterioration in the quality of life of the population. The system of green spaces of a modern city is being formed to improve the environment, enrich the appearance of the city, create conditions for mass recreation of the population in the natural environment. For the formation of the ecological situation in the city, along with cardinal measures, it is necessary to preserve and develop natural massifs and landscaping of the city territory. The article analyzes the relevant planning opportunities and constraints for urban transformation of the city, and also selects the optimal strategy for spatial development of the reorganization of the natural framework. Materials and methods. The collected attributive information, legal documents and cartographic materials are used in the work. The calculation of potential visitors was carried out on the basis of the normative value for recreational load, and the calculation of visitors to the natural-anthropogenic territorial complex (hereafter — NATC) was carried out by means of field observation. The observation results were processed using the Microsoft Office Excel software, followed by modelling of the project proposal for the use of the Reutov green space in the Qgis software package. Results. On the basis of the conducted research, the excess of the normative value of recreational load of the NATC “Apple Orchard” in Reutov was identified and a functional zoning project, including the design of three functional zones, was proposed. Conclusions. The increased rate of population influx and environmental pollution is forcing a reorganization of the green cores of cities.
{"title":"Сalculated parameters for the functional zoning of green space in the central part of Reutov","authors":"M. Slepnev, Nadeshda V. Mozgunova","doi":"10.22227/2305-5502.2023.1.8","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.8","url":null,"abstract":"Introduction. The article devoted to the relevant problem of optimizing the natural framework of the city on the basis of rational use of the territory of the settlement as a public green area. The approach, based on the modern tendencies of urbanization, ecological utility, social benefits and rational use of territories. One of the important elements of the optimization of the ecological environment is the greening of the city space. At present, maintaining the balance of urbanized areas is a priority because with the growth and development of cities, the environment is becoming more and more aggressive. Also, with the increase in the number of residents, the recreational load increases, and due to the high concentration of emissions from motor vehicles and industrial enterprises, the state of urban natural systems is changing, which leads to a deterioration in the quality of life of the population. The system of green spaces of a modern city is being formed to improve the environment, enrich the appearance of the city, create conditions for mass recreation of the population in the natural environment. For the formation of the ecological situation in the city, along with cardinal measures, it is necessary to preserve and develop natural massifs and landscaping of the city territory. The article analyzes the relevant planning opportunities and constraints for urban transformation of the city, and also selects the optimal strategy for spatial development of the reorganization of the natural framework. Materials and methods. The collected attributive information, legal documents and cartographic materials are used in the work. The calculation of potential visitors was carried out on the basis of the normative value for recreational load, and the calculation of visitors to the natural-anthropogenic territorial complex (hereafter — NATC) was carried out by means of field observation. The observation results were processed using the Microsoft Office Excel software, followed by modelling of the project proposal for the use of the Reutov green space in the Qgis software package. Results. On the basis of the conducted research, the excess of the normative value of recreational load of the NATC “Apple Orchard” in Reutov was identified and a functional zoning project, including the design of three functional zones, was proposed. Conclusions. The increased rate of population influx and environmental pollution is forcing a reorganization of the green cores of cities.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81695354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.10
S. Samchenko, D. Zorin, Nguyen Trong Lam, T. Lam
Introduction. When using concrete and reinforced concrete structures, it is necessary to overcome problems associated with the quality of concrete to shrink in size and experience shrinkage during hardening and drying. To solve problems with shrinkage, special attention is paid to the materials that, when added to ordinary portland cement, make it possible to obtain non-shrinkable, expanding types of cements. A well-known way of producing expanding cements is to grind cement clinker, gypsum and a special additive together. In addition, the introduction of active mineral additives with pozzolanic properties allows to compact the structure of the cement stone, reduce porosity, increase strength and reduce shrinkage. They also save the clinker for the cement production, help to reduce the cost of production and help to reduce the burden on the environment. One of these mineral additives is tripoli. Materials and methods. The effect of additives content on the deformation property of the composite binger was studied using the experiment planning method. Deformation of cement at the age of 2, 3, 7, 14 and 28 days were determined in accordance with the method of results processing in accordance with GOST R 56727–2015, GOST 11052–74. The research was carried out in the laboratory of the Department of Construction Materials Science of the Moscow State University of Civil Engineering. Results. The results obtained are presented as the surface of a second level regression equation describing the dependence of the blinder deformation on the content of complex expanding and pozzolanic additives. As a result of the experiments conducted, the composition with the maximum expansion and the composition with maximum shrinkage using complex additives were obtained. The results will be further used to predict the deformation properties of the binder. Conclusions. Based on the results of this study, the authors will continue to study the properties of binders based on a complex expanding and pozzolanic additive in the future.
介绍。在使用混凝土和钢筋混凝土结构时，必须克服与混凝土质量有关的尺寸收缩问题，并在硬化和干燥过程中经历收缩。为了解决收缩问题，要特别注意在普通硅酸盐水泥中添加的材料，使其有可能获得不收缩的膨胀型水泥。一种众所周知的生产膨胀水泥的方法是将水泥熟料、石膏和一种特殊的添加剂一起磨碎。此外，引入具有火山灰性质的活性矿物添加剂可以使水泥石的结构致密，减少孔隙率，提高强度并减少收缩。它们还节省了水泥生产的熟料，有助于降低生产成本，并有助于减轻对环境的负担。其中一种矿物添加剂是的黎波里。材料和方法。采用试验计划法，研究了添加剂含量对复合粘结剂变形性能的影响。按照GOST R 56727-2015、GOST 11052-74的结果处理方法，测定水泥在龄期2、3、7、14和28天的变形。这项研究是在莫斯科国立土木工程大学建筑材料科学系的实验室进行的。结果。所得结果以二级回归方程的形式描述了复合膨胀剂和火山灰添加剂含量对遮罩变形的影响。通过试验，得到了复合添加剂的最大膨胀组合物和最大收缩组合物。研究结果将进一步用于预测粘结剂的变形性能。结论。基于本研究的结果，作者将在未来继续研究基于复合膨胀和火山灰添加剂的粘结剂的性能。
{"title":"Influence of the content of complex additives on the deformation properties of cement","authors":"S. Samchenko, D. Zorin, Nguyen Trong Lam, T. Lam","doi":"10.22227/2305-5502.2023.1.10","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.10","url":null,"abstract":"Introduction. When using concrete and reinforced concrete structures, it is necessary to overcome problems associated with the quality of concrete to shrink in size and experience shrinkage during hardening and drying. To solve problems with shrinkage, special attention is paid to the materials that, when added to ordinary portland cement, make it possible to obtain non-shrinkable, expanding types of cements. A well-known way of producing expanding cements is to grind cement clinker, gypsum and a special additive together. In addition, the introduction of active mineral additives with pozzolanic properties allows to compact the structure of the cement stone, reduce porosity, increase strength and reduce shrinkage. They also save the clinker for the cement production, help to reduce the cost of production and help to reduce the burden on the environment. One of these mineral additives is tripoli. Materials and methods. The effect of additives content on the deformation property of the composite binger was studied using the experiment planning method. Deformation of cement at the age of 2, 3, 7, 14 and 28 days were determined in accordance with the method of results processing in accordance with GOST R 56727–2015, GOST 11052–74. The research was carried out in the laboratory of the Department of Construction Materials Science of the Moscow State University of Civil Engineering. Results. The results obtained are presented as the surface of a second level regression equation describing the dependence of the blinder deformation on the content of complex expanding and pozzolanic additives. As a result of the experiments conducted, the composition with the maximum expansion and the composition with maximum shrinkage using complex additives were obtained. The results will be further used to predict the deformation properties of the binder. Conclusions. Based on the results of this study, the authors will continue to study the properties of binders based on a complex expanding and pozzolanic additive in the future.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88939733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.1
N. S. Nikitina, Hieu Le Trung
Introduction. At present, the rate of growth in the development of urbanisation processes in large cities is increasing rapidly every year. At the stage of preliminary design of pile foundations, an important part is to determine the bearing capacity of the pile. Barrettes are effective foundation structures, also for high-rise buildings on soft soils. In such conditions, long barrettes are designed. At the same time the used normative methods used of calculating the bearing capacity and settlement do not take into account the features of the stress-strain state of the foundation and the interaction with barrettes in the foundations of high-rise buildings with a developed underground part. Materials and methods. The task has been considered on the basis of the results of field testing with piles (static load method) with the calculation by the analytical method according to the strength characteristics of the soil foundation, described in the regulatory documents SP 24.13330.2011 “Pile Foundations”. A new calculation method is proposed, which is set out in Appendix D of the specified set o.rules, taking into account relevant factors, such as the relative position of piles in the ground, their length, pitch, etc. Results. A graph of the dependence of settlement on load was obtained based on the results of full-scale tests of barrettes with a limiting settlement of 40 mm. Analytical results are compared with field testing of a pile in difficult engineering and geological conditions in Hanoi, Vietnam. Conclusions. The conclusions obtained by the analytical method of calculating the bearing capacity of a single barrette in terms of strength characteristics, taking into account unloading on soft soils during the development of a deep pit, are quite close to the results of static field tests. These solutions can be applied to determine the bearing capacity of piles and barrettes on soft soils.
{"title":"Methodology for evaluating the bearing capacity of a deep excavation barrette in complex geotechnical conditions in Hanoi","authors":"N. S. Nikitina, Hieu Le Trung","doi":"10.22227/2305-5502.2023.1.1","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.1","url":null,"abstract":"Introduction. At present, the rate of growth in the development of urbanisation processes in large cities is increasing rapidly every year. At the stage of preliminary design of pile foundations, an important part is to determine the bearing capacity of the pile. Barrettes are effective foundation structures, also for high-rise buildings on soft soils. In such conditions, long barrettes are designed. At the same time the used normative methods used of calculating the bearing capacity and settlement do not take into account the features of the stress-strain state of the foundation and the interaction with barrettes in the foundations of high-rise buildings with a developed underground part. Materials and methods. The task has been considered on the basis of the results of field testing with piles (static load method) with the calculation by the analytical method according to the strength characteristics of the soil foundation, described in the regulatory documents SP 24.13330.2011 “Pile Foundations”. A new calculation method is proposed, which is set out in Appendix D of the specified set o.rules, taking into account relevant factors, such as the relative position of piles in the ground, their length, pitch, etc. Results. A graph of the dependence of settlement on load was obtained based on the results of full-scale tests of barrettes with a limiting settlement of 40 mm. Analytical results are compared with field testing of a pile in difficult engineering and geological conditions in Hanoi, Vietnam. Conclusions. The conclusions obtained by the analytical method of calculating the bearing capacity of a single barrette in terms of strength characteristics, taking into account unloading on soft soils during the development of a deep pit, are quite close to the results of static field tests. These solutions can be applied to determine the bearing capacity of piles and barrettes on soft soils.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82193915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.4
Evgeniy A. Melyokhin
Introduction. The author considers designs of triangular trusses that can be used to design roofs of industrial and public buildings, various combined systems, and also as overpass structures of linear facilities. The design of a spatial truss as part of a patent pending development of a triangular truss cover with non-cutting closed-section chords is presented. The purpose of numerical studies is to estimate the stress-strain state (SSS) of a spanning triangular truss subjected to static nodal load and different arrangement of strut elements as well as to create a verification database for further numerical studies of non-faceted interface nodes. Materials and methods. The numerical research methodology takes into account the application of nodal static loads, modelling the placement of the enclosing structure of the pavement using purlins. The use of the unit load method is aimed at determining the response of the load-bearing system as part of a comparative evaluation and comparison with the data obtained from other research tasks. Results. In the course of numerical studies, data were obtained, characterising the deflected mode of the triangular truss model in terms of force distribution in the rods and vertical displacements of the nodes. Conclusions. Analysis of the obtained results shows that the accepted design model of a triangular truss adequately reflects its deflected mode. Practical application of the numerical research technique on the basis of application of unit nodal loads consists in the possibility of using calculation results in the form of a structured data set required in calculations by the limit states method. The results obtained can be used as a basis for verification of data obtained in further numerical studies of non-faceted node constructions within the framework of the lamellar mathematical model. The presented numerical studies are part of the complex of scientific research into the actual performance of spanning triangular trusses.
{"title":"Stress-strain state of a triangular truss with uncut chords of a five-sided composite profile","authors":"Evgeniy A. Melyokhin","doi":"10.22227/2305-5502.2023.1.4","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.4","url":null,"abstract":"Introduction. The author considers designs of triangular trusses that can be used to design roofs of industrial and public buildings, various combined systems, and also as overpass structures of linear facilities. The design of a spatial truss as part of a patent pending development of a triangular truss cover with non-cutting closed-section chords is presented. The purpose of numerical studies is to estimate the stress-strain state (SSS) of a spanning triangular truss subjected to static nodal load and different arrangement of strut elements as well as to create a verification database for further numerical studies of non-faceted interface nodes. Materials and methods. The numerical research methodology takes into account the application of nodal static loads, modelling the placement of the enclosing structure of the pavement using purlins. The use of the unit load method is aimed at determining the response of the load-bearing system as part of a comparative evaluation and comparison with the data obtained from other research tasks. Results. In the course of numerical studies, data were obtained, characterising the deflected mode of the triangular truss model in terms of force distribution in the rods and vertical displacements of the nodes. Conclusions. Analysis of the obtained results shows that the accepted design model of a triangular truss adequately reflects its deflected mode. Practical application of the numerical research technique on the basis of application of unit nodal loads consists in the possibility of using calculation results in the form of a structured data set required in calculations by the limit states method. The results obtained can be used as a basis for verification of data obtained in further numerical studies of non-faceted node constructions within the framework of the lamellar mathematical model. The presented numerical studies are part of the complex of scientific research into the actual performance of spanning triangular trusses.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75940907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.3
M. Sainov, Alexander A. Boldin
Introduction. The phenomenon of hydraulic fracture is associated with the failure of some earth-rock dams, in which the integrity of the core made of clay soil has been compromised. It is believed that hydraulic fracture occurs when the pressure of water contained in pores and microcracks overcomes the compressive stresses in the soil. At this point, several methods have been proposed for the computational prediction of hydraulic fracture. They are aimed at determining the conditions under which hydraulic fracture occurs and at determining the critical water pressure that causes fracture growth. Materials and methods. A review of foreign scientific publications was carried out to systematise information on methods and techniques for critical pressure determination. Results. The review gives a classification of methods for predicting hydraulic fracture. Theoretical methods are based on the usage of elasticity theory, plasticity theory or fracture mechanics. The simplest method is based on the analysis of the stress state of the soil mass. This review describes methods based on the analysis of the stress-strain state of soil around a cavity with internal pressure. They consider several mechanisms of crack propagation, including the loss of tensile and shear strength. Empirical formulas based on the results of laboratory experiments are also given. In the framework of the analytical review, a comparison of some methodologies has been carried out. Most of the methodologies agree that the critical pressure primarily depends on the minimum principal stress σ3 in the ground. The comparison showed that the critical pressure calculated by the theoretical triaxial stress analysis technique is noticeably lower than that calculated by the empirical techniques. In the presence of a cavity, the more likely cause of fracturing is the loss of shear strength of the soil rather than tensile strength. Conclusions. Despite the abundance of techniques for predicting hydraulic fracturing, no theoretically verified and accurate methodology has been established at the present time.
{"title":"Review of methods for predicting the hydraulic failure of a rockfill core dam","authors":"M. Sainov, Alexander A. Boldin","doi":"10.22227/2305-5502.2023.1.3","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.3","url":null,"abstract":"Introduction. The phenomenon of hydraulic fracture is associated with the failure of some earth-rock dams, in which the integrity of the core made of clay soil has been compromised. It is believed that hydraulic fracture occurs when the pressure of water contained in pores and microcracks overcomes the compressive stresses in the soil. At this point, several methods have been proposed for the computational prediction of hydraulic fracture. They are aimed at determining the conditions under which hydraulic fracture occurs and at determining the critical water pressure that causes fracture growth. Materials and methods. A review of foreign scientific publications was carried out to systematise information on methods and techniques for critical pressure determination. Results. The review gives a classification of methods for predicting hydraulic fracture. Theoretical methods are based on the usage of elasticity theory, plasticity theory or fracture mechanics. The simplest method is based on the analysis of the stress state of the soil mass. This review describes methods based on the analysis of the stress-strain state of soil around a cavity with internal pressure. They consider several mechanisms of crack propagation, including the loss of tensile and shear strength. Empirical formulas based on the results of laboratory experiments are also given. In the framework of the analytical review, a comparison of some methodologies has been carried out. Most of the methodologies agree that the critical pressure primarily depends on the minimum principal stress σ3 in the ground. The comparison showed that the critical pressure calculated by the theoretical triaxial stress analysis technique is noticeably lower than that calculated by the empirical techniques. In the presence of a cavity, the more likely cause of fracturing is the loss of shear strength of the soil rather than tensile strength. Conclusions. Despite the abundance of techniques for predicting hydraulic fracturing, no theoretically verified and accurate methodology has been established at the present time.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89766958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.22227/2305-5502.2023.1.7
D. Kapustin
Introduction. At the present time, in the construction of nuclear power plants (NPP), non-removable formwork made of high-strength steel fibre concrete (SFRC) is used. Due to improved physical and mechanical properties and high adhesion to monolithic concrete, the SFRC formwork is a load-bearing element. The result is a structure with combined reinforcement in the form of bar reinforcement and high-strength SRFC layers. The calculation of the actual stress-strain state of such structures requires knowing the design characteristics of used materials. High-strength SFRC is understudied material, and research of its properties, especially under long-term loads, is a crucial task. Materials and methods. Experimental studies of the effect of dispersion reinforcement parameters (type of steel fibre and its volume) on the creep value of SFRC made on a high-strength cement-sand matrix have been carried out. The research was carried out on the same matrix composition for three types of steel fibres suitable for the manufacture of 30 mm formwork sheets with a thickness of 30 mm, and most commonly found the in Russian market. A volumetric fibre content of up to 6 % was considered in the study. The load level is 0.3 of the breaking strength (prism strength). Results. The actual values of the SFRC creep parameters required to carry out the calculations of structures with combined reinforcement. Conclusions. It is found that the introduction of steel fiber up to 6 % provides a reduction of ultimate creep measure up to 20 % as compared to a fine-grained matrix. However, with up to 1.5 % volumetric content of fibre, an increase of up to 10 % in creep may also occur as a result of matrix decompaction. In the view of the large number of factors affecting the properties of SFRC, the calculated characteristics should be determined experimentally.
{"title":"Influence of dispersed reinforcement parameters on the high-strength steel fiber concrete creep perfomance","authors":"D. Kapustin","doi":"10.22227/2305-5502.2023.1.7","DOIUrl":"https://doi.org/10.22227/2305-5502.2023.1.7","url":null,"abstract":"Introduction. At the present time, in the construction of nuclear power plants (NPP), non-removable formwork made of high-strength steel fibre concrete (SFRC) is used. Due to improved physical and mechanical properties and high adhesion to monolithic concrete, the SFRC formwork is a load-bearing element. The result is a structure with combined reinforcement in the form of bar reinforcement and high-strength SRFC layers. The calculation of the actual stress-strain state of such structures requires knowing the design characteristics of used materials. High-strength SFRC is understudied material, and research of its properties, especially under long-term loads, is a crucial task. Materials and methods. Experimental studies of the effect of dispersion reinforcement parameters (type of steel fibre and its volume) on the creep value of SFRC made on a high-strength cement-sand matrix have been carried out. The research was carried out on the same matrix composition for three types of steel fibres suitable for the manufacture of 30 mm formwork sheets with a thickness of 30 mm, and most commonly found the in Russian market. A volumetric fibre content of up to 6 % was considered in the study. The load level is 0.3 of the breaking strength (prism strength). Results. The actual values of the SFRC creep parameters required to carry out the calculations of structures with combined reinforcement. Conclusions. It is found that the introduction of steel fiber up to 6 % provides a reduction of ultimate creep measure up to 20 % as compared to a fine-grained matrix. However, with up to 1.5 % volumetric content of fibre, an increase of up to 10 % in creep may also occur as a result of matrix decompaction. In the view of the large number of factors affecting the properties of SFRC, the calculated characteristics should be determined experimentally.","PeriodicalId":30543,"journal":{"name":"Stroitel''stvo Nauka i Obrazovanie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76853480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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