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.

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.

Flexural Performance of Reinforced Concrete Built-up Beams with SIFCON

2020 ◽  
Vol 38 (5A) ◽  
pp. 669-680
Author(s):  
Ghazwan K. Mohammed ◽  
Kaiss F. Sarsam ◽  
Ikbal N. Gorgis
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Conventional Concrete ◽  
Flexural Performance ◽  
Load Carrying ◽  
Fiber Concrete

The study deals with the effect of using Slurry infiltrated fiber concrete (SIFCON) with the reinforced concrete beams to explore its enhancement to the flexural capacity. The experimental work consists of the casting of six beams, two beams were fully cast by conventional concrete (CC) and SIFCON, as references. While the remaining was made by contributing a layer of SIFCON diverse in-depth and position, towards complete the overall depths of the built-up beam with conventional concrete CC. Also, an investigation was done through the control specimens testing about the mechanical properties of SIFCON. The results showed a stiffer behavior with a significant increase in load-carrying capacity when SIFCON used in tension zones. Otherwise high ductility and energy dissipation appeared when SIFCON placed in compression zones with a slight increment in ultimate load. The high volumetric ratio of steel fibers enabled SIFCON to magnificent tensile properties.

scholarly journals Flexural Performance of Small-Scale Textile-Reinforced Concrete Beams

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1178
Author(s):  
Fahed Alrshoudi
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Small Scale ◽  
Textile Fibre ◽  
Textile Reinforced Concrete ◽  
Flexural Performance ◽  
Four Point Bending ◽  
High Performance Composite

Textile-reinforced concrete (TRC) as a novel high-performance composite material can be used as a strengthening material and component bearing load alone. The flexural performance of TRC beams strengthened with textile reinforcement such as carbon tows was experimentally examined and associated with those of steel-reinforced concrete (SRC) beams. Through four-point bending tests, this research explores the effects of textile layers and dosages of short textile fibre on the flexural strength of concrete beams. A total of 64 prism samples of size 100 mm × 100 mm × 500 mm were made, flexure-strengthened, and tested to evaluate various characteristics and the efficiency of TRC versus SRC beams. TRC beams performed exceptionally well as supporting material in enhancing concrete’s flexural capacity; in addition, TRC’s average ultimate load effectiveness was up to 56% than that of SRC specimens. Furthermore, the maximum deflection was about 37% lesser than SRC beams. The results showed that by increasing the number of layers, the TRC’s effectiveness was significantly increased, and the failure mode became more ductile.

Flexural Strengthening of RC Beams with Sisal Fiber Composites and Sisal Fiber Rods

2016 ◽  
Vol 860 ◽  
pp. 144-147 ◽  
Author(s):  
Arslan Qayyum Khan ◽  
Qudeer Hussain ◽  
Winyu Rattanapitikon ◽  
Amorn Pimanmas
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Ultimate Load ◽  
Fiber Composites ◽  
Reinforced Concrete Beams ◽  
Sisal Fiber ◽  
Rc Beams ◽  
Flexural Strengthening ◽  
Four Point Bending ◽  
Ultimate Load Carrying Capacity

The present study is conducted to examine the effectiveness of sisal fiber in flexural strengthening of reinforced concrete (RC) beams. In order to obtain this objective, two different strengthening configurations are adopted (use of sisal fiber composites and use of sisal fiber rods). A total of five flexural strengthened reinforced concrete beams are instrumented and tested using a four point bending setup. The results for strength, stiffness and failure modes are discussed for the both strengthening configurations. The results demonstrate that both sisal fiber composites and sisal fiber rods are effective in enhancing ultimate load carrying capacity of RC beams. The beams strengthened with sisal fiber rods showed higher increase in ultimate load as compared with the beams strengthened with sisal fiber composites layers.

scholarly journals Analytical and Experimental Study of Flexural Strengthening of RC Members using Mechanically Fastened FRP Strips

2011 ◽  
Vol 20 (1) ◽  
pp. 096369351102000
Author(s):  
Angeliki Papalou ◽  
Thanasis C. Triantafillou
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Flexural Strengthening ◽  
Concrete Members ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Mechanically Fastened ◽  
Frp Strips ◽  
Increasing Load

The main objective of this work is to investigate the behaviour of reinforced concrete members strengthened for flexure using mechanically fastened fiber reinforced polymer (FRP) strips. Experiments were conducted on strengthened reinforced concrete beams loaded to failure with an increasing load in four-point bending. An analytical-numerical model was developed predicting the behaviour of the strengthened concrete beam and reproducing its large ductility before failure.

Experimental study on the durability of FRP bars reinforced concrete beams in simulated ocean environment

2018 ◽  
Vol 25 (6) ◽  
pp. 1123-1134 ◽  
Author(s):  
Zhiqiang Dong ◽  
Gang Wu ◽  
Jinlong Lian
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Constant Load ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Flexural Performance ◽  
Frp Composite ◽  
Steel Bars ◽  
Ocean Environment ◽  
Frp Bars

AbstractIn this paper, the flexural performance of fiber-reinforced polymer (FRP) bars reinforced concrete (RC) beams after conditioning in a simulated seawater wet-dry cycling environment for 6, 9 and 12 months is experimentally investigated. Two types of FRP bars, i.e. basalt FRP (BFRP) bars and steel-FRP composite bars (SFCBs), are adopted. Steel bars are employed for comparison. During the conditioning, a constant load is coupled to the beams. A total of 24 simply supported beams are tested. In addition, microscopic damage to the conditioned BFRP bars is detected by scanning electron microscopy (SEM). The test results indicated that total corrosion was observed at the surface of the bottom longitudinal steel bars after a maximum exposure of 12 months. However, the degradation of the macro-mechanical properties of the steel bars RC beam was not distinct. The ultimate load of the BFRP bars RC beams after 6 months, 9 months and 12 months was reduced by 22%, 33% and 42%, respectively. The yield load and ultimate load of the SFCBs RC beams were reduced by a maximum of 18% and 38%, respectively. The SEM observations revealed that there were distinct damages at the outer layer of the BFRP bars after 12-month conditioning.

scholarly journals Flexural Behavior of Ultra-High Performance Fiber Reinforced Concrete Scale Tunnel Segment

2018 ◽  
Vol 38 ◽  
pp. 03037
Author(s):  
Kun Ni ◽  
Fa Sheng Zhang ◽  
Yun Xing Shi ◽  
Yan Gang Zhang ◽  
Jing Bin Shi
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Ultimate Load ◽  
Fiber Reinforced Concrete ◽  
Flexural Behavior ◽  
Fiber Reinforced ◽  
Flexural Performance ◽  
Four Point Bending ◽  
High Performance Fiber ◽  
Elastic Stage

To reduce the weight of precast tunnel segment, ultra-high performance fiber reinforced concrete (UHPFRC) was studied to cast the segment. The flexural performance of UHPFRC scale tunnel segments were tested in this work. The weight of the UHPFRC thinner scale tunnel segment was only 80% of reinforced concrete (RC) segment. The segments were loaded as per CJJ/T 164-2011, and the four-point bending system was used. The results showed that the cracking load increased 50%, and 0.2 mm crack width load increased 22%, and the yield load increased 11%, and the ultimate load only decreased 1%. The stiffness of elastic stage of UHPFRC segment looked the same compared to RC segment. In a word, the UHPFRC thinner segments showed excellent flexural performance beyond the traditional RC segment.

The Research of the Bending Crack Resistance Ability of Reinforced Concrete Beam Mixed with Emulsified Asphalt

2012 ◽  
Vol 217-219 ◽  
pp. 1146-1150
Author(s):  
Bao Kuan Ning ◽  
Guo Qing Liu ◽  
Yi Nan Ren ◽  
Feng Lin Xu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Deformation Capacity ◽  
Asphalt Emulsion ◽  
Bending Tests ◽  
Four Point Bending ◽  
Emulsified Asphalt

By four-point bending tests on the reinforced concrete beams with emulsified asphalt of different parameters, cracks, deformation and bearing capacity were observed and recorded during destructive process, and then a comparison were made between the experiment results and those of ordinary reinforced concrete beams. The results prove that lower emulsified asphalt dosage (1% to 3%) can significantly improve the overall deformation of reinforced concrete beams; while higher asphalt emulsion parameters (5% to 7%) reduce the beam intensity and do not improve the toughness and overall deformation capacity.

scholarly journals Structural Behavior of Strengthened RC Beams in Shear using CFRP Strips

2017 ◽  
Vol 11 (1) ◽  
pp. 205-215
Author(s):  
Amer M. Ibrahim ◽  
Ahmed Abdullah Mansor ◽  
Muthafer Hameed
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Failure Model ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Concrete Members ◽  
Theoretical Investigations

Carbon fiber reinforced polymers (CFRP) were widely used in strengthening of reinforced concrete members in the last few years. Experimental and theoretical investigations were carried out to find the behavior of reinforced concrete beams strengthened in shear by CFRP strips. Six beams measured of 200x300x2000mm were investigated. The variables investigated in this work are orientation (vertical and inclined) and the spacing between CFRP strips. It was found that the strengthening by CFRP strips increased the crack, yield and ultimate load by 10%, 71% and 77% respectively on average. Inclined CFRP strips show a better performance than vertical CFRP strips with same distances and increase the yield and ultimate load by 11% and 13% respectively on average. By covering all faces of specimen with CFRP strips, the yield and ultimate load increased by 82% and 95% respectively. Using the CFRP strips changed the failure model from shear to flexural by increasing the shear strength, so the ductility was increased by 198% on average. CFRP increased the strain in compression face of concrete and the value was greater than (0.003). For all strengthened specimens, there was no effect on CFRP strips.

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.

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