scholarly journals Effect of the Nonprestressed/Prestressed BFRP Bar on Flexural Performance of the Bamboo Beam

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Qingfang Lv ◽  
Yi Ding ◽  
Ye Liu
Keyword(s):  
Ultimate Load ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Prestress Loss ◽  
Bending Tests ◽  
Flexural Performance ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Laminated Bamboo

Until now, the systematical and comprehensive strengthening techniques have not been formed for the bamboo structure. Under such background, this paper aims to explore the effects of the application of the nonprestressed and prestressed basalt fiber-reinforced polymer (BFRP) bars on the flexural performance of the beams made of the laminated bamboo and reconstituted bamboo materials. Two series of four-point bending tests were thus conducted. In the first series of tests, the pure laminated bamboo beam and the laminated bamboo beam applied with nonprestressed BFRP bar were compared. Test results showed that the ultimate load and deformation capacity of the laminated bamboo beam was improved due to the existence of the BFRP bar. In the second series of tests, the reconstituted bamboo beams applied with nonprestressed and prestressed BFRP bars were compared. It is found that the ultimate load of the reconstituted bamboo beam was not improved by the application of the prestressed force. The further analysis related to the prestress loss demonstrated that the prestress loss before the release of the prestressed BFRP bar could reach up to 31.8–37.3% compared with the design initial prestressed stress. The prestress loss caused by the elastic deformation of the bamboo beam can be neglected. For all tested specimens, the plane section assumption was acceptable and the position of the neutral axis of the beam gradually moved down with the increase of the applied load.

scholarly journals Analyses on Prestress Loss and Flexural Performance of the Laminated Bamboo Beam Applied with Prestressed BFRP Sheet

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Qingfang Lv ◽  
Ye Liu ◽  
Yi Ding
Keyword(s):  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Specimen Preparation ◽  
Fiber Reinforced ◽  
Prestress Loss ◽  
Loading Test ◽  
Flexural Performance ◽  
Ultimate Deformation ◽  
Reinforced Polymer ◽  
Laminated Bamboo

Inspired by the studies about wooden beam applied with prestressed steel plate and bamboo beam strengthened by fiber-reinforced polymer (FRP), this paper aims to explore the applicability of the prestressed basalt fiber-reinforced polymer (BFRP) sheet to the laminated bamboo beam and the variation of the flexural performance of the laminated bamboo beam applied with prestressed BFRP sheet. Two series of tests were conducted in the present study. In the first series of tests, the prestress loss of the prestressed BFRP sheet was classified and analyzed based on measured strains and deflections, which led to a derivation of the effective prestressed force considering the prestress loss. Analyses showed that the recommended value of prestress loss compared with the initial prestressed force was 22.0% based on the existing test data in the specimen preparation stage. In the second series of tests, the static loading test was performed to investigate the flexural performance of the laminated bamboo beam applied with prestressed BFRP sheet and analyze the difference between the laminated bamboo beams applied with prestressed and non-prestressed BFRP sheets. Test results showed that the no significant variation of the ultimate load and a reduction of the ultimate deformation capacity were caused by the application of the prestressed BFRP sheet.

scholarly journals Experimental Investigation of the Fatigue Behavior of Basalt Fiber Reinforced Polymer Grid-Concrete Interface

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bo Wen ◽  
Chunfeng Wan ◽  
Lin Liu ◽  
Da Fang ◽  
Caiqian Yang
Keyword(s):  
Failure Modes ◽  
Fatigue Behavior ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Fiber Reinforced ◽  
Loading Level ◽  
Reinforced Polymer ◽  
Concrete Interface ◽  
Basalt Fiber Reinforced Polymer

Fatigue behavior is an important factor for mechanical analysis of concrete members reinforced by basalt fiber reinforced polymer (BFRP) grid and polymer cement mortar (PCM) and plays a critical role in ensuring the safety of reinforced concrete bridges and other structures. In this study, on the basis of the static loading test results of concrete specimens reinforced by BFRP grid and PCM, a series of fatigue tests with different loading levels were conducted on interfaces between BFRP grid and concrete to investigate the fatigue behavior of BFRP grid-concrete interfaces. The test results indicate that with high loading level, the fatigue failure mode of interface is interfacial peeling failure while it transforms to the fatigue fracture of the BFRP grid under low loading level. The fatigue life (S-N) curves of BFRP grid-concrete interface are obtained and fitted in stages according to different failure modes, and the critical point of the two failure modes is pointed out. The relative slip evolution of interface during fatigue is further revealed in different stages with two failure modes, and the law of interface strain is studied with the increase of fatigue times. The relation of effective bonding length of interface and fatigue times is also described.

Flexural performance of composite grid panels with deep ribs

2020 ◽  
Vol 39 (11-12) ◽  
pp. 443-458
Author(s):  
Jiye Chen ◽  
Hai Fang ◽  
Feng Gao ◽  
Weiqing Liu
Keyword(s):  
Glass Fiber ◽  
Bending Stiffness ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Flexural Performance ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Composite Grid

This paper reports on the flexural performance of an innovative composite grid panel composed of glass fiber-reinforced polymer face skins and deep glass fiber-reinforced polymer ribs with a trapezoidal cross-section. Three-point and four-point bending experiments were performed to demonstrate the feasibility of the composite grid panels under concentrated loads. Compared with the composite grid panels without skins, maximum increases in the ultimate load, and initial bending stiffness of the composite grid panels of approximately 68.2% and 306.7%, respectively, were achieved with the existence of both upper and lower skins. Furthermore, an analytical analysis was carried out to predict the initial bending stiffness and mid-span deflection of the composite grid panels. A comparison of the analytical and experimental results showed that the analytical model accurately predicted the flexural performance of the composite grid panels subjected to three-point and four-point bending. Failure mechanism maps were constructed to predict the mechanical response and failure modes of the composite grid panels. Moreover, the validated model was used in a parametric analytical study to further estimate the effects of various parameters on the flexural performance of the composite grid panels. The results demonstrated that the initial bending stiffness can be significantly improved by increasing the trapezoidal section ratio, face skin thickness, and grid height.

Flexural Strengthening of Reinforced Concrete Beams with Prestressed CFRP Plates

2011 ◽  
Vol 255-260 ◽  
pp. 3077-3081 ◽  
Author(s):  
Lang Ni Deng ◽  
Hua Chen ◽  
Kan Kang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Bending Tests ◽  
Control Beam ◽  
Flexural Strengthening ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Anchorage System

Four medium -scale reinforced concrete beams were constructed and tested to investigate the effectiveness of external poststrengthening with prestressed carbon fiber reinforced polymer (CFRP) plates. The various variables included the strengthening method and the amount of prestressing. The experiments consisted of one control beam, one nonprestressed CFRP-bonded beam, and two prestressed CFRP-bonded beams, all the beams were subjected to four-point bending tests. In comparison to the control beam and the nonprestressed CFRP-bonded beam, the cracking load, yield load, ultimate load and stiffness of the beams with bonded prestressed CFRP plates were increased. The failure mode of the prestressed CFRP-plated beams was not debonding, but concrete crushing. After the debonding of the CFRP plates, the behaviour of the bonded CFRP-plated beams changed to that of unbonded CFRP-plated beams due to the effect of the anchorage system. The ductility of the beams strengthened with CFRP plates having the anchorage system was considered high if the ductility index was above 3.

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.

Study on Flexural Performance of RC Beams Strengthened with Prestressed CFRP Plates

2011 ◽  
Vol 250-253 ◽  
pp. 3361-3366
Author(s):  
Hua Chen ◽  
Kan Kang ◽  
Lang Ni Deng ◽  
Peng Zhang
Keyword(s):  
Ultimate Load ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Yield Load ◽  
Flexural Performance ◽  
Reinforced Polymer

For RC beams strengthened with prestressed carbon fiber reinforced polymer (CFRP) plates, calculate methods for the cracking load, the yield load and the ultimate load are derived base on the analysis of normal section stress. The test of reinforced concrete beams strengthened with prestressed CFRP plates were carried out, and analytical results are compared with experimental results. Comparisons show that the calculated values agree well with the experimental results.

Flexural Behaviour of RC Beams Strengthened with Prestressed CFRP Plates：Comparisons of Bonded and Unbonded Method

2011 ◽  
Vol 480-481 ◽  
pp. 283-287
Author(s):  
Lang Ni Deng ◽  
Peng Zhang ◽  
Hua Chen
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Reinforced Concrete Beams ◽  
Flexural Behaviour ◽  
Bending Tests ◽  
Flexural Performance ◽  
Concrete Members ◽  
Four Point Bending ◽  
Anchorage System ◽  
Externally Bonded

In this study, a total of 5 CFRP-strengthened reinforced concrete beams were tested in flexure based on the independent development prestressing anchorage system. The various variables included bonding or no bonding of the CFRP and the amount of prestressing. The experiments consisted of one control beam, two prestressed CFRP-unbonded beams, and two prestressed CFRP-bonded beams, all the beams were subjected to four-point bending tests. The ultimate load, deformation, and CFRP strain were examined. The aim of this investigation was to study the flexural performance of reinforced concrete members strengthened using CFRP plates, employing different CFRP bonding and prestressing methods. The failure mode of the prestressed CFRP-plated beams was not debonding, but concrete crushing or FRP rupture. For the reinforced concrete members strengthened with externally bonded prestressed CFRP plates, after the debonding of the CFRP plates that occurred in the bonded cases, the behaviour of the bonded CFRP-plated beams changed to that of the unbonded CFRP-plated beams due to the effect of the anchorage system. The ductility indices of the beams in an unbonded system were less than that of those in a bonded system.

scholarly journals Improving the Adhesion of BFRP Strips to the Concrete Surface

2019 ◽  
Vol 2 (2) ◽  
pp. 220-228
Author(s):  
Hasan Hüseyin Akbalık ◽  
Ali Sarıbıyık
Keyword(s):  
Concrete Strength ◽  
Basalt Fiber ◽  
Concrete Surface ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Frp Composites ◽  
Adhesion Ability ◽  
Four Point Bending ◽  
Frp Composite ◽  
Reinforced Polymer

Fiber Reinforced Polymer (FRP) composites are widely used in repair and strengthening of reinforced concrete structural elements. The FRP composite adhered to the concrete surface may be separated from the concrete surface in the form of debonding before reaching the ultimate strength. Epoxy resin, concrete strength, fiber properties and application method have an important role in bonding of FRP composites to concrete surfaces. In this study, concrete beam specimens were produced in order to investigate the adhesion of Basalt Fiber Reinforced Polymer (BFRP) composites to the concrete surface using conventional concretes. Stress distribution between concrete and BFRP was investigated by opening a gap in the bottom center of the samples. Unidirectional basalt fiber fabric was used in the production of the test specimens. The effects of concrete surface properties and U winding method on the end of fiber adhesion ability were investigated by bonding BFRP composite to the lower surfaces of the Specimens. Specimens were tested by four point bending experiment. According to the results obtained, the grinding of the concrete surface and the U-winding method significantly improve the adhesion.”

Experimental Study on Flexural Performance of Corroded RC Beams Strengthened with AFRP Sheets

2009 ◽  
Vol 405-406 ◽  
pp. 343-349 ◽  
Author(s):  
Zong Cai Deng ◽  
Jian Hui Li ◽  
He Fei Lin
Keyword(s):  
Experimental Study ◽  
Mass Loss ◽  
Ultimate Load ◽  
Fiber Reinforced Polymer ◽  
Rc Beam ◽  
Rc Beams ◽  
Yield Load ◽  
Flexural Performance ◽  
Reinforced Polymer ◽  
Strengthened Beam

In order to investigate the strengthening effects of aramid fiber reinforced polymer (AFRP) sheets on the flexural performance of the corroded beams, the flexural behaviors of corroded RC beams strengthened with AFRP sheets under different degrees of corrosion (minor: reinforcement mass loss is 2.0％, medium: reinforcement mass loss is 6.0％) are researched experimentally in this paper, and compared with that of the control beams (un-corroded) and un-strengthened corroded beams. The results show that，compared with un-strengthened corroded beams under same degrees of corrosion, the cracking load, yield load and ultimate load of minor corroded RC beam strengthened with AFRP sheets is respectively increased by 20%, 27% and 60%, and increased by 15%, 36% and 83% for medium corroded RC beam strengthened with AFRP sheets respectively; The ultimate deflection of the medium corroded beam strengthened with AFRP sheets is 166% larger than that of corroded un-strengthened beam. AFRP sheets can improve significantly the bearing capacity and deformation for corroded RC beams.

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