scholarly journals The use of FRP of increased thickness for strengthening structures

2021 ◽  
Vol 263 ◽  
pp. 02033
Author(s):  
Oleg Simakov
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Cross Sections ◽  
Experimental Studies ◽  
Calculation Methods ◽  
Reinforcement System ◽  
External Reinforcement ◽  
Concrete Elements

The external reinforcement system based on carbon fiber has been used for decades to strengthen reinforced concrete elements. At the same time, it is impossible not to recognize that the existing calculation methods are largely based on empirical dependencies obtained from experimental studies. One of these issues is related to the application of the methodology for materials of heterogeneous origin-tapes and laminates. In general, the possibility of applying the calculation methods accepted in the norms for laminates of generally accepted thicknesses up to 1.6 mm is determined. The question related to the possibility of using laminates of greater thickness is not sufficiently studied. This article deals with the calculation of the reinforcement of the normal cross sections of the bent reinforced concrete elements with the reinforcement of laminates with a thickness of 5 mm.

scholarly journals Improved engineering method for calculating the strength of the supporting areas of reinforced concrete elements

2018 ◽  
Vol 230 ◽  
pp. 02014 ◽  
Author(s):  
Olena Krantovska ◽  
Mykola Petrov ◽  
Liubov Ksonshkevych ◽  
Sergii Synii ◽  
Pavlo Sunak
Keyword(s):  
Reinforced Concrete ◽  
Comparative Analysis ◽  
Cross Sections ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Standard Methods ◽  
Refined Method ◽  
Eurocode 2 ◽  
The World ◽  
Concrete Elements

According to the results of experimental studies, empirical dependencies were obtained (obtained from the appropriate mathematical models). The advanced (refined) method of engineering calculation of express-estimation of the strength of sloping cross sections of elements of flexible reinforced concrete structures on the basis of comparative analysis of the obtained empirical dependencies and standard accepted methods in the world was developed (nine basic norms are taken: DSTU B.V.2.6-156:2010 (Ukraine), previously operating SNiP 2.03.01-84*, SNB 5.03.01-02 (Belarus), SR 63.13330.2012 (Russia), Eurocode 2, 2004 (European Union), ACI 318-M14 (USA), AIJ Code, 2007 (Japan), CSA 23.3-04 (Canada), DIN 1045-1 (Germany). The coefficient of variation of bearing capacity and accident ratio according to the results of calculations of standard methods are determined. Their comparative analysis is carried out and informative graphic figures are presented.

scholarly journals ANALYSIS OF STRENGTHENING OF COMPRESSED REINFORCED CONCRETE STRUCTURES USING REINFORCED CONCRETE JACKETS / GNIUŽDOMŲJŲ GELŽBETONINIŲ KONSTRUKCIJŲ STIPRINIMO GELŽBETONINIAIS APVALKALAIS ANALIZĖ

2011 ◽  
Vol 3 (2) ◽  
pp. 76-84
Author(s):  
Saulius Pilkavičius
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Calculation Methods ◽  
Advantages And Disadvantages ◽  
Calculation Algorithms ◽  
Capacity Calculation ◽  
Basic Equations ◽  
Concrete Elements

This article investigates two chosen calculation methods of compressed reinforced concrete elements strengthened using reinforced concrete jackets. Shortly describe carrying capacity calculation algorithms of these calculation methods. Present elements basic equations and dependences of carrying capacity. For calculation methods of carrying capacity comparison and adjustment executed carrying capacity experimental studies of compressed fiber reinforcement concrete elements strengthened using reinforcement concrete jackets. Were compared theoretical calculations of carrying capacity results with experimental carrying capacity results. Shortly describe advantages and disadvantages of analyzed calculation methods and experimental research. By the comparison of calculation methods conclusions and experimental studies conclusions, produces improved calculation method of carrying capacity.

Calculation Of Carbon Fiber Anchors For Pull-Out And Shear When Installing External Reinforcement Systems

2020 ◽  
pp. 4-8
Keyword(s):  
Composite Materials ◽  
Carbon Fibers ◽  
Experimental Studies ◽  
The Body ◽  
Carbon Fibres ◽  
Calculation Methods ◽  
Regulatory Documents ◽  
Pull Out ◽  
External Reinforcement ◽  
Concrete Elements

The operation of external reinforcement systems based on carbon fibers when strengthening normal and inclined sections of bending reinforced concrete elements depends largely on the anchoring to the body of the reinforced structure. In addition to adhesion, one of the options for ensuring the required level of anchoring of external reinforcement is the installation of anchoring elements, including those based on carbon fibers. This article discusses the calculation of anchors based on carbon fibres used in the arrangement of the external reinforcement system. Two principles of anchor arrangement operation are highlighted: for shear and for pull-out. Separate design provisions have been developed for each, taking into account the parameters of anchoring elements and the nature of the destruction obtained during experimental studies. The proposed calculation methods are based on experimental studies of both bending elements reinforced by external reinforcement systems and directly anchoring elements. In addition, the development of these methods takes into account the provisions available in the regulatory documents on the calculation of anchors and composite materials.

scholarly journals Initial crack effect on the strength of oblique cross sections of reinforced concrete beams strengthened with carbon fiber

2019 ◽  
Vol 110 ◽  
pp. 01053
Author(s):  
Alexandr Shilov ◽  
Petr Polskoy ◽  
Dmitriy Mailyan ◽  
Petr Shilov
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Cross Sections ◽  
Structural Damage ◽  
Concrete Beams ◽  
Experimental Studies ◽  
Reinforced Concrete Beams ◽  
Shear Span ◽  
The Impact ◽  
Initial Cracks

In the theory of reinforced concrete, the issue on strength of the oblique beam sections is more complicated than that on the standard sections, since it depends on many factors. The change of at least one of them leads to a significant change in the carrying capacity and in the structural damage pattern. This is due to the fact that at the operating level of the load, all conventional reinforced concrete structures work with cracks, which must be considered in the calculation. However, in the existing regulatory documents and public sources, this issue is not specified. This paper considers the effect of initial cracks on the strength of oblique cross sections of the reinforced concrete beams strengthened with carbon fiber. The experimental studies results obtained through the transverse force testing of forty-two prototypes made of heavy concrete of B30 design grade are presented. The test samples had initial oblique cracks of 0.6-0.9 mm width and were reinforced with three composite U stirrups from the fabric based on unidirectional carbon fibers in the shear span. Initial cracks in the beams were formed at three values of the shear span – 1.5h0, 2h0 and 2.5h0. The test data show the impact of initial cracks on the efficiency of composite reinforcement of oblique cross sections of the prototypes at various values of shear spans.

scholarly journals MODELS OF BAY REINFORCED CONCRETE ELEMENTS RESISTANCE AT ACTION OF CYCLE PERMANENT SIGN HIGH LEVEL FORCES

2018 ◽  
Vol 1 (50) ◽  
pp. 112-123 ◽  
Author(s):  
V. M. Karpiuk ◽  
A. I. Kostiuk ◽  
Yu. A. Somina
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
Physical Models ◽  
Cyclic Loads ◽  
Longitudinal Reinforcement ◽  
Calculation Methods ◽  
Cyclic Action ◽  
High Level ◽  
Creep Deformations ◽  
Concrete Elements

The reinforced concrete span beam structures work with small, middle and large shear spans under the action of cyclic loads of high levels is investigated. It is established that researches of physical models development of bending reinforced concrete elements fatigue resistance to the cyclic action of transverse forces and calculation methods on its base are important and advisable due to following features of said load type: the nonlinearity of deformation, damage accumulation in the form of fatigue micro- and macrocracks, fatigue destruction of materials etc. The key expressions of the concrete endurance limits definition (objective strength), longitudinal reinforcement, anchoring of longitudinal reinforcement, which consists the endurance of whole construction are determined. Also the role and the features of influence of vibro-creep deformations on the change mechanics of stress-strain state of concrete and reinforcement of research elements are investigated.

scholarly journals Optimizing of system "column-cfrp lamellas" with the strengthening of civil structures

2021 ◽  
Vol 9 (1) ◽  
pp. 1-5
Author(s):  
Irina Mayackaya ◽  
Batyr Yazyev ◽  
Anastasia Fedchenko ◽  
Denis Demchenko
Keyword(s):  
Reinforced Concrete ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Concrete Structures ◽  
Polymeric Composite ◽  
Concrete Columns ◽  
Reinforced Concrete Structures ◽  
Structural Elements ◽  
Civil Structures ◽  
Concrete Elements

Reinforced concrete elements of structures in the form of columns, beams, ceilings are widely used in the construction of buildings and structures of industrial and civil construction. In most cases, the columns serve as supports for other building elements, for example, crossbars, slabs, girders, beams. One of the cycles of the work of reinforced concrete structures is the state of their repair and reconstruction, including the stages of strengthening the elements. There is a problem of strengthening of reinforced concrete columns. The article deals with the issue of reinforcing columns and other structural elements having a cylindrical surface, with polymeric composite materials in the form of carbon fiber lamellae. The use of composite materials allows to increase the service life and strength of reinforced concrete structures used in construction.

Using of Plastic Hinges in the Calculation of Buildings against Progressive Collapse under Fire Exposure

2018 ◽  
Vol 878 ◽  
pp. 115-120
Author(s):  
Levon Avetisyan
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Experimental Studies ◽  
Fire Exposure ◽  
Reinforced Concrete Frame ◽  
Dynamic Calculation ◽  
Plastic Hinges ◽  
Concrete Frame ◽  
In Fire ◽  
Concrete Elements

This article presents a study of the strength of a 25-storey reinforced concrete frame against progressive collapse in fire conditions. Taking into account the angles of disclosure of plastic hinges as norming for the strength of reinforced concrete elements, a computer technology program has been developed and included in PR Wolfram Mathematica 10 for the dynamic calculation of compressed reinforced concrete elements under fire exposure on the basis of the conducted experimental studies. Dynamic calculation of the strength of eccentrically compressed reinforced concrete columns was carried out, with operation in normal conditions and under high temperatures. The diagram «moment-curvature» and the graph of the change of the static and dynamic strength of the column depending on the temperature were developed. Nonlinear dynamic analysis of a 25-storey reinforced concrete frame was conducted, taking into account the changes of the dynamic characteristics of reinforced concrete elements in fire and, the estimation of resistance of the frame was given.

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