scholarly journals The analysis of crack width in flexural concrete members reinforced with polymer composite bars

Vestnik MGSU ◽  
2020 ◽  
pp. 1663-1672
Author(s):  
Ilshat T. Mirsayapov ◽  
Igor A. Antakov ◽  
Alexey B. Antakov
Keyword(s):  
Crack Width ◽  
Experimental Studies ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Calculation Methods ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Frp Reinforcement

Introduction. Rebars, made of fiber-reinforced polymers (FRP), have a number of distinguishing characteristics and disadvantages along with well-known strengths, such as high tensile strength, low specific density, high corrosion resistance, and low thermal conductivity. One of its principal strengths is the modulus of elasticity which is relatively low compared to steel. As a result, elements, having FRP reinforcement, feature higher deformability. In this regard, the requirements of serviceabi-lity limit states, applicable to structures, may become the main obstacle to the use of FRP as the reinforcement for concrete members. It is assumed that cracking patterns of members, having FRP reinforcement, may differ from those of traditional reinforced concrete structures. Materials and methods. Experimental studies were carried with regard for and in compliance with the provisions of National State Standard 8829-94. Tested samples represented concrete beams that were 1,810 mm long and had a cross section of 120 × 220 mm. Their tensile side was reinforced with two bars. Steel, glass fiber-reinforced polymer (GFRP) and basalt fiber-reinforced polymer (BFRP) bars were used to reinforce the beams. The value of the reinforcement ratio varied. Crack width calculation methods, applied according to Construction rules and regulations 63.13330.2012 and 295.1325800.2017 (Russia) and ACI 440.1R-06 (USA) were analyzed. Results. The results of the theoretical and experimental studies of the crack resistance of flexural members having FRP reinforcement are obtained. Discrepancies between the calculation methods are identified. Conclusions. Сracking patterns, typical for members having FRP reinforcement, are specified. They contest the applicabi-lity of methods, prescribed in the Construction Rules and Regulations. The methods, prescribed by Construction Rules and Regulations 63.13330.2012 and 295.1325800.2017, differ in respect of crack width calculations, and it leads to diverging calculation results.

scholarly journals To the design of the deflections of flexural concrete members reinforced with fiber-reinforced polymer bars

Vestnik MGSU ◽  
2021 ◽  
pp. 413-428
Author(s):  
Ilshat T. Mirsayapov ◽  
Igor A. Antakov ◽  
Alexey B. Antakov
Keyword(s):  
Experimental Studies ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced Polymers ◽  
Strain Diagram ◽  
Fiber Reinforced ◽  
Calculation Methods ◽  
Short Term ◽  
Reinforced Polymer ◽  
Frp Reinforcement

Introduction. Fiber-reinforced polymers (FRP) reinforcement has a relatively low modulus of elasticity compared to steel. In this connection, the bent members with such reinforcement have a higher deformability. The stress-strain diagram for FRP under short-term loading is almost straight and does not have a yield line, as in steel reinforcement. At the same time, modern methods of calculating structures with for FRP reinforcement are based on existing approaches for reinforced concrete structures. In this regard, the current direction for study is to assess the reliability and improve the existing methods for calculating members with FRP reinforcement for the serviceability limit states. Materials and methods. Experimental studies were carried with regard for and in compliance with the provisions of National State Standard 8829-94. Tested samples represented concrete beams that were 1,810 mm long and had a cross section of 120 × 220 mm. Their tensile side was reinforced with two bars. Steel, glass fiber-reinforced polymer (GFRP) and basalt fiber-reinforced polymer (BFRP) bars were used to reinforce the beams. The value of the reinforcement ratio varied. Deflections calculation methods, applied according to Construction rules and regulations 295.1325800.2017 (Russia) and ACI 440.1R-06 (USA) were analyzed. Results. The results of the theoretical and experimental studies of the deformability of flexural members having FRP reinforcement are obtained. The inaccurate determination of the cracking moment Mcrc has a negative impact on the results of the deflection calculation. The deviation of the theoretical values of the cracking moment according to the method of Construction rules and regulations 295.1325800.2017 from the experimental ones is 26.2–59.1 %, in the method of ACI 440.1 R-06 — 20.1–57.1 %. For the ACI 440.1 R-06 method, the calculation is more accurate, in which the short-term deflection was multiplied by the factor λ = 0,6ξ = 0,6 · 2 = 1,2, for the Construction rules and regulations 295.1325800.2017 method — when using ψf = 1 – 0,8Mcrc / M. Conclusions. The results obtained showed the need to improve the considered calculation methods. To increase the accuracy of the calculation of deflections according to the method of SP 295.1325800.2017, at the first stage, it is possible to approximate the theoretical values of the cracking moment to the experimental data by introducing correction factor in the equation according to the calculation of Mcrc: for beams with a GFRP high-bond bars — 0.7, for BFRP with a sanded surface — 0.5.

Effects of temperature on the behaviour of fiber reinforced polymer reinforced concrete members: experimental studies

2000 ◽  
Vol 27 (5) ◽  
pp. 993-1004 ◽  
Author(s):  
Mamdouh M Elbadry ◽  
Hany Abdalla ◽  
Amin Ghali
Keyword(s):  
Thermal Expansion ◽  
Reinforced Concrete ◽  
Thermal Stresses ◽  
Experimental Studies ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Concrete Members ◽  
Reinforced Polymer ◽  
Effects Of Temperature

Thermal characteristics of fiber reinforced polymer (FRP) reinforcement can be substantially different from those of concrete and conventional steel reinforcement. The influence of this difference on the behaviour of FRP reinforced concrete members is studied in this paper. Concrete beams reinforced with different types of FRP rebars are tested under the effects of temperature gradient while the rotation at the two ends of the beam are restrained. The bending moments and cracking developed by the thermal gradient are monitored. The results are compared with those obtained from tests on beams of the same dimensions but reinforced with steel bars. The behaviour of thermally cracked members is also investigated under mechanical load effects at both service and ultimate load levels. The potential cracking of the concrete cover caused by the transverse thermal expansion of FRP bars is examined by testing concrete cylinders. The experiments show the difference in thermal behaviour of glass and carbon FRP and steel bars.Key words: bond, concrete, cracking (fracturing), fiber reinforced polymers, loads (forces), reinforcement, temperature, tensile strength, thermal expansion, thermal stresses.

Compressive behavior of circular and square concrete column externally confined by different types of basalt fiber–reinforced polymer

2020 ◽  
Vol 23 (8) ◽  
pp. 1534-1547 ◽  
Author(s):  
Jingting Huang ◽  
Tao Li ◽  
Dayong Zhu ◽  
Peng Gao ◽  
An Zhou
Keyword(s):  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced Polymers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Compressive Behavior ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Polymer Wrapping ◽  
Basalt Fiber Reinforced Polymer

This article studies the compressive behavior of concrete columns confined by different basalt fiber–reinforced polymers. A total of 30 columns were divided into 10 groups according to section shapes (circular and square), basalt fiber–reinforced polymer types (unidirectional basalt fiber–reinforced polymer, bidirectional basalt fiber–reinforced polymer, and hybrid basalt fiber–reinforced polymer/carbon fiber–reinforced polymers), and number of layers (0, 1, and 2). The test results showed that the compressive strengths of confined specimens increased by 20%–71% for circular columns and by 23%–41% for square columns. Similarly, the ultimate strains improved by 49%–296% for circular specimens and by 45%–145% for square specimens. The two-layer basalt fiber–reinforced polymer jacket had the best confinement effect, whereas the confining effect of bidirectional basalt fiber–reinforced polymer wrapping was relatively lower than that of unidirectional basalt fiber–reinforced polymer wrapping. Moreover, both the strength and ultimate strain of confined concrete improved with increasing number of basalt fiber–reinforced polymer layers. Finite element numerical models were also developed and verified by experimental results, and then the stress distributions of basalt fiber–reinforced polymer jackets and cross-sectional concrete were presented. Based on the test results and experimental data from several existing studies, modified strength and ultimate strain models were further developed for basalt fiber–reinforced polymer-confined circular and square columns.

scholarly journals Experimental Study on Strengthening of RC Short Columns with BFRP Sheets

2018 ◽  
Vol 7 (3.12) ◽  
pp. 48
Author(s):  
Arathi Krishna ◽  
Milu Mary Jacob ◽  
K Saravana Raja Mohan
Keyword(s):  
Experimental Studies ◽  
Basalt Fiber ◽  
Load Condition ◽  
Primary Objective ◽  
Fiber Reinforced Polymer ◽  
Analytical Models ◽  
Fiber Reinforced ◽  
Short Columns ◽  
Reinforced Polymer ◽  
Materials Used

Earlier the methods adopted for the repair and rehabilitation were the external bonding of the damaged component with steel fibers and steel jackets. But the major problem that caused due to this steel components is corrosion. Fiber Reinforced Polymer (FRP) composite materials used for strengthening of components in the form of confinement is of considerable importance in civil engineering. This paper presents the results of axially loaded RC short columns which are strengthened by providing confinement with new material BFRP. The primary objective of this work is to examine the load carrying capacity of concrete columns confined with basalt fiber reinforced polymer jacket (BFRP) which is considered as an abstruse material for strengthening. BFRP materials are non-corrosive, non-magnetic, and chemical resistant and they are progressively being used for repair, rehabilitation, and strengthening of structures that are not stable enough to carry loads. The parameters considered in the study are full and partial wrapping and the number of layers of confinement. The results obtained from the experimental studies and the analytical models precisely shows that the BFRP confinements will upgrade the compressive strength of columns under the given load condition.

scholarly journals Durability and Mechanical Properties of Concrete Reinforced with Basalt Fiber-Reinforced Polymer (BFRP) Bars: Towards Sustainable Infrastructure

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1402
Author(s):  
Osama Ahmed Mohamed ◽  
Waddah Al Hawat ◽  
Mohammad Keshawarz
Keyword(s):  
Carbon Steel ◽  
Experimental Studies ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Sustainable Infrastructure ◽  
Reinforced Polymer ◽  
Reinforced Beams ◽  
Minimal Environmental Impact ◽  
Basalt Fiber Reinforced Polymer

Reducing the fingerprint of infrastructure has become and is likely to continue to be at the forefront of stakeholders’ interests, including engineers and researchers. It necessary that future buildings produce minimal environmental impact during construction and remain durable for as long as practicably possible. The use of basalt fiber-reinforced polymer (BFRP) bars as a replacement for carbon steel is reviewed in this article by examining the literature from the past two decades with an emphasis on flexural strength, serviceability, and durability. The provisions of selected design and construction guides for flexural members are presented, compared, and discussed. The bond of BFRP bars to the surrounding concrete was reportedly superior to carbon steel when BFRP was helically wrapped and sand coated. Experimental studies confirmed that a bond coefficient kb = 0.8, which is superior to carbon steel, may be assumed for sand-coated BFRP ribbed bars that are helically wrapped, as opposed to the conservative value of 1.4 suggested by ACI440.1R-15. Code-based models overestimate the cracking load for BFRP-reinforced beams, but they underestimate the ultimate load. Exposure to an alkaline environment at temperatures as high as 60 °C caused a limited reduction in bond strength of BFRP. The durability of BFRP bars is influenced by the type of resin and sizing used to produce the bars.

BFRP Bars as an Alternative Reinforcement of Concrete Structures - Compatibility and Adhesion Issues

2015 ◽  
Vol 1129 ◽  
pp. 233-241 ◽  
Author(s):  
Andrzej Garbacz ◽  
Marek Urbański ◽  
Andrzej Łapko
Keyword(s):  
Concrete Structures ◽  
Basalt Fiber ◽  
Technical Characteristic ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforcing Bars ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Reinforced Beams

One of the most common causes of damage to concrete structures is the corrosion of the reinforcement. Reinforcement made from Fiber Reinforced Polymers (FRP) is considered as an attractive substitution of traditional steel reinforcement. A different technical characteristic of fiber reinforced polymer makes designing structures with FRP reinforcement differs from conventional reinforced concrete design. Therefore, it is necessary to identify the differences and limitations of their use in the concrete structures, taking into account their material and geometrical features. Basalt Fiber Reinforced Polymer (BFRP) is a relatively new material for reinforcing bars. On the basis of the ACI 440.1R-06 guidelines as well as experimental results for selected BFRP reinforced beams a model of compatibility in a system: BFRP bar - concrete was proposed. Additionally, based on the results of FEM simulations, the effect of BFRP bars ribbing on their adhesion to concrete was discussed.

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