scholarly journals The civil structures bearing capacity assessment for 150 m high reinforced concrete ventilation pipe based on the field and numerical surveys

2020 ◽  
Vol 23 (1) ◽  
pp. 18-26
Author(s):  
M.H. Marienkov ◽  
K.M. Babik ◽  
D.V. Bogdan
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Ultrasonic Method ◽  
Concrete Structures ◽  
Capacity Assessment ◽  
Building Structures ◽  
Design Models ◽  
Spatial Design ◽  
Linear And Nonlinear ◽  
Seismic Impacts

In the paper the results of the building structures bearing capacity assessment are presented for a reinforced concrete ventilation pipe with a height of 150 m under seismic effects and tornado loads, taking into account the results of full-scale dynamic and instrumental building structures surveys, based on the linear and nonlinear spatial design models numerical studies. This goal was achieved by solving the following tasks: the vibrodynamic surveys execution; the concrete structures strength determination by an ultrasonic method; development of linear and nonlinear spatial design models of the pipe; the calculations of class F3 tornado effects and intensities 6 (MDE) and 7 (above MDE) seismic impacts. Based on the results of vibrodynamic surveys, the actual dynamic parameters of the ventilation pipe structures were determined (vibration modes, prevailing periods and frequencies during principal modes vibrations). Based on the results of structures instrumental studies by ultrasonic method, the actual characteristics of concrete structures strength are determined. The obtained field data were used in the development of the facility spatial design models. To determine the bearing capacity of structures, the models calculations were performed using the LIRA CAD software package, which is a computer system for structural analysis and design. The calculations were performed for the class F3 tornado loads, as well as the intensities 6 and 7 seismic effects determined by the spectral method. Additionally, the bearing capacity of facility reinforced concrete structures was assessed under extreme loads (intensity 7 seismic impacts and class F3 tornado) taking into account the concrete and reinforcement plastic properties. The structures non-linear static analysis (Pushover analysis) applied in the standards of Ukraine, the European Union, the USA and other countries for the assessment of the operating structures seismic resistance was used. Based on the results of the research, the reinforced concrete ventilation pipe structures stress-strain state parameters under the considered seismic and tornado loads were obtained and the recommendations were prepared to reduce the possible consequences of an intensity 7 earthquake and a class F3 tornado.

scholarly journals The civil structures bearing capacity assessment for 150 m high reinforced concrete ventilation pipe based on the field and numerical surveys

2020 ◽  
Vol 23 (1) ◽  
pp. 18-26
Author(s):  
M.H. Marienkov ◽  
K.M. Babik ◽  
D.V. Bogdan
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Ultrasonic Method ◽  
Concrete Structures ◽  
Capacity Assessment ◽  
Building Structures ◽  
Design Models ◽  
Spatial Design ◽  
Linear And Nonlinear ◽  
Seismic Impacts

In the paper the results of the building structures bearing capacity assessment are presented for a reinforced concrete ventilation pipe with a height of 150 m under seismic effects and tornado loads, taking into account the results of full-scale dynamic and instrumental building structures surveys, based on the linear and nonlinear spatial design models numerical studies. This goal was achieved by solving the following tasks: the vibrodynamic surveys execution; the concrete structures strength determination by an ultrasonic method; development of linear and nonlinear spatial design models of the pipe; the calculations of class F3 tornado effects and intensities 6 (MDE) and 7 (above MDE) seismic impacts. Based on the results of vibrodynamic surveys, the actual dynamic parameters of the ventilation pipe structures were determined (vibration modes, prevailing periods and frequencies during principal modes vibrations). Based on the results of structures instrumental studies by ultrasonic method, the actual characteristics of concrete structures strength are determined. The obtained field data were used in the development of the facility spatial design models. To determine the bearing capacity of structures, the models calculations were performed using the LIRA CAD software package, which is a computer system for structural analysis and design. The calculations were performed for the class F3 tornado loads, as well as the intensities 6 and 7 seismic effects determined by the spectral method. Additionally, the bearing capacity of facility reinforced concrete structures was assessed under extreme loads (intensity 7 seismic impacts and class F3 tornado) taking into account the concrete and reinforcement plastic properties. The structures non-linear static analysis (Pushover analysis) applied in the standards of Ukraine, the European Union, the USA and other countries for the assessment of the operating structures seismic resistance was used. Based on the results of the research, the reinforced concrete ventilation pipe structures stress-strain state parameters under the considered seismic and tornado loads were obtained and the recommendations were prepared to reduce the possible consequences of an intensity 7 earthquake and a class F3 tornado.

scholarly journals OBJECTS OF TRANSPORT INFRASTRUCTURE: EXPERIENCE OF SCIENTIFIC SUPPORT IN CONSTRUCTION WITHIN THE “QUALITY” CONCEPT IMPLEMENTATION

2019 ◽  
Vol 16 (5) ◽  
pp. 618-634
Author(s):  
I. S. Pulyaev ◽  
S. M. Pulyaev
Keyword(s):  
Reinforced Concrete ◽  
Building Materials ◽  
Concrete Structures ◽  
Economic Feasibility ◽  
Transport Infrastructure ◽  
Building Structures ◽  
Construction Technology ◽  
Scientific Support ◽  
Free Construction ◽  
Modern Building

Introduction. The paper deals with the issues related to the implementation of the “quality” concept in the construction of reinforced concrete transport facilities linked with the scientific support during design and construction. Nowadays this problem particularly relevant in the context of the modern construction solutions, combined with the need to obtain the required properties of concrete structures and ensure the economic feasibility of construction. The aim of the research is to generalize and systematize the main methods and techniques of concrete works, which minimize the defects and cracks while the construction of transport infrastructure.Materials and methods. On the example of different technologies used in the Russian construction over last 10 years, the authors demonstrated the developed methods of obtaining high quality concrete products taking into account tested and proved modern building materials.Results. The results of the research formed the basis of the projects, technological regulations for the production, specifications and standards of organizations, guidelines. Moreover, the results also allowed implementing the concept of “quality” in transport construction based on obtaining defect-free reinforced concrete structures with specified properties, taking into account the use of modern building materials.Discussion and conclusions. The research allows carrying out construction of various massiveness and extent. The obtained results form the basis of construction technology of other industrial and civil construction objects with reinforced concrete application. The paper is interesting and useful for specialists in providing defect-free construction of reinforced concrete building structures, for engineering and technical staff. The authors dedicate the research to the memory of Professor and Doctor of Technical Sciences, A.R. Solovyanchik (1938-2019).

scholarly journals Bearing capacity of RC beams reinforced with high strength rebars and steel plate

2018 ◽  
Vol 230 ◽  
pp. 02003 ◽  
Author(s):  
Taras Bobalo ◽  
Yaroslav Blikharskyy ◽  
Rostyslav Vashkevich ◽  
Myhailo Volynets
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Concrete Structures ◽  
High Strength ◽  
Strength Properties ◽  
Rc Beams ◽  
Reinforcing Bars ◽  
External Reinforcement ◽  
Effective Use

Nowadays, reducing the material content of not only buildings and structures in general, but also individual constructions is a topical task that can be realized through the use of high-strength concrete and reinforcement, as well as with the use of external reinforcement. The concentrated location of sheet reinforcement on the external the most tense facets of steel and concrete structures increases the operating height of the cross-section, makes it possible to more effectively use the strength properties of steel in comparison with conventional reinforced concrete, and with the same bearing capacity to economize on expenses. Composite and monolithic reinforced concrete structures with external reinforcement are used in various construction sectors around the world. This contributed to the expansion of the use of reinforced concrete for special buildings of power-engineering and hydrotechnical construction. The technical nd econom efficiency, as well as the possibility of using external rebar as formwork for monolithic concrete construction, have been proved. Therefore, there is a need for the study of structures with combined reinforcement, in which high rigidity of steel and concrete structures is combined with an effective use of high-strength reinforcing bars (rebar) without prior tension

Nonlinear Analysis of Bearing Capacity of Reinforced Concrete Structures Using Strip Method

2013 ◽  
Vol 470 ◽  
pp. 921-924
Author(s):  
Hai Chao Tan
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Nonlinear Analysis ◽  
Rectangular Cross Section ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Strip Method ◽  
Basic Assumptions ◽  
Steel Bars ◽  
Fortran Language

As the progress of theory and computer technology, nonlinear analysis is widely applied in civil engineering. Strip method, as one of the numerical methods, is used widely especially in the analysis of beams, columns and shell structures. The first half of this paper introduces the theoretical model and the basic assumptions of the strip method; the latter half of this paper compiles the strip method into computer program using FORTRAN language. At last, using beams with rectangular cross-section of reinforced concrete structures as an example, the paper analyze the factors, such as the strength of the steel bars, which have an impact on the bearing capacity of reinforced concrete structures.

scholarly journals FLEXURAL REINFORCED CONCRETE ELEMENTS NORMAL SECTION BEARING CAPACITY EVALUATION IN FRACTURE STAGE

2017 ◽  
Vol 9 (2) ◽  
pp. 70-78 ◽  
Author(s):  
Justas SLAITAS ◽  
Zbynek HLAVAC ◽  
Arnoldas ŠNEIDERIS
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Crack Depth ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Assessment Process ◽  
Reinforced Concrete Structures ◽  
Compression Zone ◽  
Normal Section

This article examines flexural reinforced concrete structures condition assessment process in existing buildings on the stage where the reinforcement stress is between the yield and the tensile strength. The research is made on V. Jokūbaitis proposed methodology directly measuring the compression zone height, allowing us to evaluate the behavior of reinforced concrete beam fracture sufficiently precisely. This paper confirms the hypothesis that, when reinforcement reaches yielding stress, elastic strain dominates in concrete‘s compression zone and it is reasonable to use triangular concrete compression zone diagram, without tensile concrete above crack evaluation. The methodology of reinforced concrete structures bearing capacity assessment according to limit normal section crack depth is proposed. There is established connection between bending moments, when reinforcement achieve yielding stress and tensile strength, which allows us to decide about structures bearing capacity reserve. The results are confirmed with experimental studies and calculated values obtained by methodologies based on different reduced stress diagrams of concrete‘s compressive zone.

scholarly journals Directions of Convergence of the Requirements of the Main Domestic Standard for the Design of Concrete and Reinforced Concrete Structures SP 63.13330.2012 with the Requirements of the International Standard ISO 19338

2019 ◽  
pp. 93-98
Author(s):  
Sergey B. Krylov ◽  
Ravil S. Sharipov ◽  
Sergey A. Zenin ◽  
Yury S. Volkov
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Structures ◽  
National Standards ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Design Standards ◽  
Structural Concrete ◽  
International Standard ◽  
Assessment Requirements

Design standards on building structures should contain, first of all, the performance and assessment requirements of structures. At the same time, design standards should provide the possibility for design and construction of concrete and reinforced concrete parts of buildings and structures that meet the requirements of the Technical regulations "On the safety of buildings and structures". Taking into account the importance of ensuring the reliability and safety of buildings and structures erected with the use of structural concrete, the technical Committee of the international organization for standardization ISO TC 71 "Concrete, reinforced concrete and prestressed concrete", certifies national standards for compliance with the requirements of the international standard ISO 19338 "Performance and Assessment Requirements for Design Standards on Structural Concrete", developed by the same Committee. The standard describes the issues that should be included in the standards for the design of concrete and reinforced concrete structures (terms and definitions, basic requirements, performance requirements,loads and impacts, design estimates, requirements for manufacturing and construction, as well as quality control). These requirements are common to all standards in the design of concrete and reinforced concrete structures. In this regard, it is relevant and important to establish the possibility of presenting the National Code of rules SP 63.13330.2012 "SNiP 52.01-2003 Plain and Reinforced Concrete Structures. General Provisions" for certification for compliance with the requirements of ISO 19338. To achieve this goal, the relevant work has been done, based on the results of which were made the proposals for the submission of SP 63.13330.2012 for certification for compliance with ISO 19338:2014. These proposals are set out in the text of the article.

scholarly journals Creating Conditions for the Industrial Application of Basalt-Plastic Reinforcement in Manufacturing Precast Concrete Structures

2020 ◽  
Vol 9 (4) ◽  
pp. 143-147
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Bearing Capacity ◽  
Industrial Application ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Road Construction ◽  
Steel Reinforcement ◽  
Composite Polymer ◽  
Composite Reinforcement

The search for alternative methods of replacing steel reinforcement in load-bearing reinforced concrete structures with composite polymer reinforcement is an urgent scientific and practical task. Composite reinforcement (basalt-plastic, fiberglass) is an economically viable alternative to steel reinforcement; it possesses high tensile strength and chemical resistance, light weight (more than 4 times lighter than the steel ones), low thermal conductivity, radio transparency, dielectric properties. Such properties make it possible to use this type of reinforcement of concrete structures in civil, industrial, and road construction. Only in recent years, the specialists in Uzbekistan have paid special attention to the need for composite polymer reinforcement in construction. This type of reinforcement makes it possible to increase the service life of concrete structures and the building as a whole and to reduce the country's dependence on imports of steel reinforcement. At present the production of basalt-plastic reinforcement is localized in the country – its fiber is made from local basalt. For the possibility of industrial application of composite polymer reinforcement in construction, it is necessary to establish a relationship between a customer, a designer, and a manufacturer. For a customer, the project must be economically profitable, a designer must understand the physical and mechanical properties of the reinforcement and know the regulatory base, and a manufacturer must be interested in producing quality units and assemblies in accordance with the interstate standards, and be sure that the reinforcement produced by him will be in demand. The high deformability of structures caused by the low modulus of elasticity of composite reinforcement does not allow the manufacture of structures that work as bending and eccentrically compressed elements, embedded in reinforced concrete; however, it is noted that such reinforcement can be used in structures for which the requirements for the second group of limiting states are not determinant. The national standards acting in the CIS countries and other states limit the scope of application of composite polymer reinforcement in concrete structures in industrial objects of the economic complex. An analysis of the actual operation of prefabricated road panels, taking into account the low deformation characteristics of basalt-plastic reinforcement, showed the possibility of replacing steel reinforcement with a composite polymer one according to the criterion of uniform strength in terms of design tensile strengths while maintaining the number of working reinforcement bars and their location in reinforcing units. The results of testing the pilot panels of the road surface (prefabricated ones) reinforced with basalt-plastic reinforcement were considered to determine their crack resistance and bearing capacity. The test results of experimental road panels show that the bearing capacity not only decreased but substantially increased. The high corrosion resistance of basalt-plastic reinforcement, when used in road panels, contributes to an increase in the service life of such panels, since the values of crack opening under operational loads are set lower than the permissible limit values. The results of this study show that it is possible to expand the scope of industrial application of basalt-plastic reinforcement in the production of precast concrete structures, for example, for road construction. To do this, it is necessary to create a regulatory framework based on the results of relevant research work.

scholarly journals Сomparative analysis of the methods of strengthening of masonry, metal structures, reinforced concrete, such as traditional methods and the alternative methods of strengthening by FRP-materials

2020 ◽  
pp. 267-291
Author(s):  
Iryna Rudnieva
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Alternative Methods ◽  
Building Structures ◽  
Traditional Methods ◽  
External Appearance ◽  
Metal Structures ◽  
Advantages And Disadvantages ◽  
Heritage Buildings ◽  
Determining Factor

Built mostly centuries ago, heritage buildings as well the more contemporary buildings of the last century, which have lost the bearing capacity often need restoration and strengthening, especially in seismic regions and in regions with shrinkage phenomena (subsidence region). The need of strengthening of the building constructions during exploitation appears mostly because of their premature wear as a result of technological influences and weathering, various damage and various other factors. Traditional methods of strengthening are effective, but in some cases not appropriate or not applicable  for use. An example is the increase of the load-bearing structures of historical buildings, preserving the external appearance of which is the determining factor. In this case, the use of the discussed alternative methods can be justified alternative. Knowledge of the causes of defects and damage of structures allows to choose the best option of repairing or strengthening. The aim of the research is the evaluation of the structural performance of composite fibre-reinforced elements in the wider sector of the conservation of historical, architectonic and environmental heritage, as well the more contemporary buildings of the last century, which have lost of the bearing capacity focusing reliability indexes and the appearance of the structure. In the article was described and analyzed the existing traditional methods and the alternative methods of strengthening by FRP-materials (composite materials) such building structures as masonry, metal structures, reinforced concrete, and the computation in software ABAQUS. These procedures of strengthening building structures by FRP-materials  in Ukraine are not widely used due to the lack of a regulatory framework that would regulate their use, as well because these materials are relatively expensive compared to the traditional ones. The article analyzed the existing methods of computation and design of the strengthening using FRP-materials, and the computation in software ABAQUS was performed with conclusions and recommendations based on results of the computation. The aim of the work was to review the technology and analyze the advantages and disadvantages of each of the strengthen methods that should be used when choosing effective solutions for strengthening building structures. In conclusion, the need for further study and researches was confirmed.

How does concrete strength affect the fire resistance?

2020 ◽  
Vol 11 (3) ◽  
pp. 311-324
Author(s):  
Eva Lubloy
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Fire Safety ◽  
Strength Class ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Building Structures ◽  
Content Type ◽  
Upper Limit

Purpose The aim of the research was to investigate the effect of concrete strength on the fire resistance of structures. At first, it may seem contradictory that higher concrete strengths can decrease the fire resistance of building structures. However, if the strength of the concrete exceeds a maximum value, the risk of spalling (the detachment of the concrete surface) significantly. Design/methodology/approach Prefabricated structural elements are often produced with higher strength. The higher concrete strengths generally do not cause a reduction in the load bearing capacity, but it can have serious consequences in case of structural fire design. Results of two prefabricated elements, namely, one slab (TT shaped panel) and one single layer wall panel, were examined. Results of the specimen with the originally designed composition and a specimen with modified concrete composition were examined, were polymer fibres were added to prevent spalling. Findings As a result of the experiments, more strict regulations in the standards the author is suggested including more strict regulations in the standards. It has been proved that to ensure the fire safety of the reinforced concrete structures, it is required after polymer fibres even in lower concrete strength class than prescribed by the standard. In addition, during the classification and evaluation of structures, it is advisable to introduce an upper limit of allowed concrete strength for fire safety reasons. Originality/value As a result of the experiments, the author suggests including more strict regulations in the standards. It has been proved that to ensure the fire safety of the reinforced concrete structures, it is necessary to require the addition of polymer fibres even in lower concrete strength class than prescribed by the standard. In addition, during the classification and evaluation of structures, it is advisable to introduce an upper limit of allowed concrete strength for fire safety reasons.

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