Fire Resistance Of Concrete Structures With Composite Rod Reinforcement

2019 ◽  
pp. 50-55 ◽  
Keyword(s):  
Bearing Capacity ◽  
Fire Resistance ◽  
Concrete Structures ◽  
Protective Layer ◽  
Maximum Temperature ◽  
Regulatory Requirements ◽  
Composite Rod ◽  
The Moment ◽  
Normative Value ◽  
Composite Reinforcement

The use of composite rod reinforcement makes it possible to ensure the durability of reinforced concrete structures, operated under aggressive conditions. The use of composite reinforcement in concrete structures requires solving the problem of fire resistance of this class of structures. The fire resistance of the composite rod reinforcement is determined by the moment of softening of the composite rod matrix as a result of heating under fire conditions. The maximum temperature for various composite materials is 150 °Ñ – 250 °C. When designing, it is necessary to ensure the normative value of the limit of fire resistance of structures. For the bearing structures of the frame, the fire resistance limit corresponds to the moment of loss of the bearing capacity, for the intermediate floors – the loss of bearing capacity, integrity and thermal insulation ability. The main factor that provides the fire resistance of concrete structures with rod composite reinforcement is the thickness of the protective layer of concrete which ensures the joint operation of composite rods with concrete. Diagrams of the temperature change over the thickness of a concrete structure are presented, on the basis of them the methodology for the assignment of the value of the protective layer of concrete for the core composite reinforcement for different designs with due regard for the duration of fire effect in case of fire is proposed. The nomenclature of structures in which it is possible to use the rod composite reinforcement with the provision of regulatory requirements for the limit of fire resistance is determined.

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.

Fire Resistance of Reinforced Concrete Corrosion-Damaged Columns of the "Standard" Fire

2019 ◽  
Vol 828 ◽  
pp. 163-169
Author(s):  
Ashot Georgievich Tamrazyan ◽  
Micheal Sergeevich Mineev ◽  
Aishat Urasheva
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Fire Resistance ◽  
Protective Layer ◽  
Operating Conditions ◽  
Corrosive Environment ◽  
Reinforced Concrete Column ◽  
Cross Sectional ◽  
Standard Fire ◽  
The Cross

The article describes the features of the effect of corrosion of reinforcement on the bearing capacity of reinforced concrete columns in a "standard" fire. On the basis of the standard calculation method, the fire resistance of the column was estimated under a four-sided fire effect taking into account the different duration of the fire. The study examined the operation of the column in a corrosive environment, it was assumed that the initiation of corrosion of concrete and reinforcement will occur after 10 years of exploitation. It was found that the destruction of concrete protective layer 25 mm thick in a medium aggressive environment will occur after 25 years, and the diameter of the reinforcement during this period will decrease by 20%. To compare the results, a reinforced concrete column with a section of 400x400mm was calculated under the influence of a “standard” fire under normal operating conditions and taking into account work in a corrosive environment. The results of heat engineering calculations are presented, where the temperature changes in the reinforcement depending on the heating time and reduction of the protective layer thickness, as well as the change in the diameter of the reinforcement and its effect on the bearing capacity are shown. It has been established that reducing the cross-sectional area of the working reinforcement and reducing the cross-sectional dimensions of the column due to the occurring corrosion processes leads to a decrease in the fire resistance limit on the loss of bearing capacity by 58%.

scholarly journals COMPARATIVE ANALYSIS OF RESEARCH AND CALCULATED VALUES OF BEARING CAPACITY OF REINFORCED CONCRETE AND BASALT CONCRETE BEAMS ACCORDING TO RECOMMENDATIONS OF NATIONAL DESIGN STANDARDS

2020 ◽  
pp. 43-49
Author(s):  
I. Karpiuk ◽  
◽  
V. Karpiuk ◽  
E. Klimenko ◽  
A. Tselikova ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Comparative Analysis ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Design Standards ◽  
Metallic Composite ◽  
Regulatory Documents ◽  
Foreign Countries ◽  
Composite Reinforcement

Abstract. Non-metal composite reinforcement is increasingly being used in modern construction. Composite reinforcement is a great step forward over steel, due to its higher strength and corrosion resistance. An analysis of the use of these fittings was performed, which showed that the United States, Japan and China are leading countries in the use of composite fittings. The more active pace of implementation of composite reinforcement is limited by the fact that composite reinforcement does not have a common method for calculating their bearing capacity. That is why the article discusses regulatory documents on the calculation and design of structures reinforced with composite reinforcement from around the world. The article provides a comparative analysis of the calculations of the bearing capacity of prototypes – beams, reinforced with basalt-plastic reinforcement, according to the available design standards of foreign countries, which were among the first to use non-metallic composite reinforcement for reinforcing span concrete structures. The methods of calculating the bearing capacity of beam elements for concrete and non-metallic composite reinforcement according to regulatory documents are examined in detail. A comparative analysis of the actual bearing capacity of inclined sections of basalt concrete beams and its calculated values calculated according to the recommendations of the existing design standards of foreign countries is carried out. The analysis showed that the actual bearing capacity of the inclined sections of basalt concrete beams and its calculated value showed their unsatisfactory convergence. A common feature of all considered foreign design standards is the underestimation, up to several times, of the bearing capacity of inclined sections of prototypes ‒ beams reinforced with both steel and basalt-plastic reinforcement. It has been established that the methods for calculating the bearing capacity of supporting sections of spans of reinforced concrete and basalt concrete structures, presented in national design standards, are based not on the new general method, but on partially improved methods that were used in previously existing standards.

scholarly journals Innovative ways of concrete water supply structures repair with composite materials

2021 ◽  
Author(s):  
O. A. Baev ◽  
◽  
Yu. M. Kosichenko ◽  
Keyword(s):  
Water Supply ◽  
Bearing Capacity ◽  
Water Permeability ◽  
Concrete Structures ◽  
Protective Layer ◽  
Bentonite Clay ◽  
Impregnation Method ◽  
Advantages And Disadvantages ◽  
Technical Developments ◽  
Technical Solutions

Purpose: modern scientific and technical developments for repairing concrete structures and lined water supply structures, including those for which patents for inventions have been obtained are considered. Some of the considered technical solutions can be attributed to innovative developments. Materials and Methods: the known methods of repairing concrete structures of water-supply structures and linings were studied as research materials, their advantages and disadvantages were noted. Particular attention is paid to technical solutions for which patents for inventions have been obtained. Results: damage repair of concrete linings of water-supply structures in the form of cracks and destruction of expansion joints is most common, since at the same time water permeability decreases, and the bearing capacity increases. Repair by surface impregnation method is carried out to strengthen the protective layer of reinforced concrete structures to a depth of 15–35 mm. Repair of local disturbances is carried out manually at a depth of destruction less than 0.1 m. Areal disturbances with an area of more than 1 m² and a destruction depth of more than 0.1 m are recommended to be repaired mechanically. Invention no. 1477877 proposes a method for repairing construction structures and facilities, which is carried out by the method of pressure injection of repair compounds, they increase the quality of repair due to the reliability of defective zones filling. Innovative methods of facing repairing include sealing damage by injecting bentonite mortar during data remote transmission from humidity sensors to a personal computer (patent no. 2612431), as well as a method of sealing the joints of facings, including an anti-filtration bundle in the form of a hollow cylinder filled with bentonite clay (patent no. 2598635). Conclusions: repair of damage to concrete water-supply linings is the most common, since the water permeability of the concrete structure decreases at the same time as the bearing capacity changes.

Study on the Data-Bases for Fire Engineering Design of Structural Steels Members

2012 ◽  
Vol 628 ◽  
pp. 156-160
Author(s):  
In Kyu Kwon ◽  
Hyung Jun Kim ◽  
Heung Youl Kim ◽  
Bum Yean Cho ◽  
Kyung Suk Cho
Keyword(s):  
Bearing Capacity ◽  
Fire Resistance ◽  
Engineering Method ◽  
Fire Tests ◽  
Structural Members ◽  
Data Bases ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
In Fire ◽  
Resistance Performance

Structural steel has been used since the early 1970’s in Korea as primary structural members such as columns, beams, and trusses. The materials have much higher strength such as fast construction, high load bearing capacity, high construction quality but those have a fatal weakness as well. Load-bearing capacity is going down when the structural members are contained in fire condition. Therefore, to protect the structural members made of steels from the heat energy the fire resistance performance required. Generally, the fire resistance performance have evaluated from the exact fire tests in fire furnaces. But the evaluation method takes much more time and higher expenses so, the engineering method requires. The engineering method not only adopts a science but also an engineering experience. In this paper, to make various data-bases for evaluation of structural members such as columns(H-section, RHS), beams, loaded fire tests were conducted and derived not only each limiting temperature but also fire resistance respectively.

scholarly journals OPTIMIZATION OF INORGANIC COMPONENTS OF FIRE PROTECTIVE VARNISH FOR WOOD

2021 ◽  
pp. 123-132
Author(s):  
Yu. Tsapko ◽  
◽  
А. Tsapko ◽  
O. Bondarenko ◽  
V. Lomaha ◽  
...  
Keyword(s):  
High Temperature ◽  
Fire Retardant ◽  
Protective Layer ◽  
Combustion Products ◽  
Wood Products ◽  
Maximum Temperature ◽  
Protective Film ◽  
Insulating Layer ◽  
Combustible Gases ◽  
Material Studies

Abstract. The processes of creation of fire-retardant varnish for wood consisting of a mixture of inorganic and polymeric substances are investigated in the work. It is established that the optimization of the inorganic component leads to a directional ratio of mineral acids and urea capable of effective fire protection of the material. Studies have shown that at the initial temperature of gaseous combustion products T = 68 °C, when exposed to the radiation panel, the untreated sample ignited after 146 s, the flame spread over the entire surface, instead, the sample fire-protected varnish did not ignite, the maximum temperature was 105 °C. In this case, as evidenced by the results of heat resistance, there is a change in the structure of the protective film of the coating. The thickness of the protective layer increases due to the decomposition of the composition, which leads to inhibition of oxidation in the gas and condensed phase, change the direction of decomposition towards the formation of non-combustible gases and combustible coke residue, reduce material combustion and increase flammability index. The coating under the influence of high temperature promotes the formation of a heat-insulating layer of coke, which prevents burning and the passage of high temperature to the material, which is confirmed by the absence of the process of ignition of fire-retardant wood. Features of braking of process of ignition and distribution of a flame of the wood processed by a varnish which consist in several aspects are established. This is the formation of a heat-insulating layer of coke, which prevents burning and the passage of high temperatures to the material, which is confirmed by the absence of the process of ignition of fire-retardant reeds. This indicates the possibility of targeted control of high temperature transfer processes to organic material through the use of special coatings for wood products.

scholarly journals Analysis of the Effect of the Solid-Brick Infilled Frames on the Behavior of A Hybrid System of Moment Resistance Frame, Shear Wall, and Infilled Frame Along High Concrete Structures

2015 ◽  
Vol 10 (Special-Issue1) ◽  
pp. 789-795
Author(s):  
Mehdi Shekarbeigi ◽  
Hooshang Shekarbeigi
Keyword(s):  
Hybrid System ◽  
Software Package ◽  
Concrete Structures ◽  
Shear Wall ◽  
Structural System ◽  
System Behavior ◽  
Base Shear ◽  
Infilled Frames ◽  
Infilled Frame ◽  
The Moment

This paper is to investigate the benefits of a new structural system (hereafter it is referred as “Ultra Hybrid System”) in high concrete buildings relying on the compound performance of the moment resistance frame, shear wall and infilled frame. In this case, the Ultra Hybrid System takes the advantage of the moment resistance frame and shear wall up to the height, where the wall performance reaches zero, while it is applied the infilled frame along with it. It is studied the system behavior based on using concrete-brick infilled frames in the upper floors to find out the interaction between the shear wall and infilled frame. Then, it is compared displacement, relative floor displacement, base shear, axial column loads in a hybrid system of the moment resistance frame and shear wall and the Ultra Hybrid System of the moment resistance frame, shear wall, and infilled frame. In this study, ETABS 2000 software package )Barkhordari et al., 2001) is used to model the system in compression diagonal mode. Finally, the results are presented in diagrams and tables.

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