scholarly journals Flexural Strengthening of RC Continuous T-Beams Using CFRP

Fibers ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 41
Author(s):  
Ayssar Al-Khafaji ◽  
Hani Salim
Keyword(s):  
Beam Width ◽  
Experimental Investigations ◽  
Width Ratio ◽  
Flexural Strengthening ◽  
Cfrp Sheets ◽  
Modes Of Failure ◽  
Reinforced Polymer ◽  
Negative Moment ◽  
Ultimate Failure ◽  
T Beam

In this paper, experimental investigations for strengthening reinforced concrete (RC) continuous beams were performed. Eighteen T-beams were cast, twelve of which were inverted T-beams where the flange portion of the T-beam was subjected to positive flexure to represent the support region of a continuous beam. Six of the T-beams were non-inverted where the web is subjected to positive flexure. Carbon fiber reinforced polymer (CFRP) sheets with different widths were considered, and different strengthening configurations with the same area of CFRP were investigated. The use of one-layer, multiple layers, or multiple strips of CFRP were evaluated to investigate the effect of these configurations on the ultimate capacity and ductility of the strengthened beams. From the experimental observation of the non-inverted beams, it was found that the ultimate load capacities of the CFRP-strengthened beams were enhanced by 4% to 90% compared to the control beam. Using multiple layers of CFRP sheets enhanced the stiffness of the beams by 4% to 46%, depending on the CFRP area and configurations. The debonding of CFRP before the ultimate failure provided additional ductility to the tested beams. For the strengthening of the inverted beams, it was found that the addition of CFRP strips did not increase the strength of the beams when the width of CFRP to beam width ratio was less than 0.25, but the ductility of the beam was enhanced slightly. The use of multiple strips was found to be a more effective way for the strengthening of the negative moment region than using multiple layers. This can also provide more desirable modes of failure than when applying CFRP in multiple layers. Ductility was found to be lower if multiple layers were used compared to other configurations. Moreover, it was observed that as the compressive strength of concrete increased the addition of the CFRP improved the beams ductility.

scholarly journals An experimental study on flexural strengthening of RC beams using CFRP sheets

2018 ◽  
Vol 7 (4) ◽  
pp. 2075 ◽  
Author(s):  
Yasmin Murad
Keyword(s):  
Flexural Strength ◽  
Orientation Angle ◽  
Longitudinal Axis ◽  
Flexural Behavior ◽  
Experimental Program ◽  
Rc Beams ◽  
Rc Structures ◽  
Flexural Strengthening ◽  
Cfrp Sheets ◽  
Reinforced Polymer

 The use of carbon fiber reinforced polymer (CFRP) sheets is becoming a widely accepted solution for strengthening and repairing rein-forced concrete (RC) structures. To date, the behavior of RC beams, strengthened with 60˚ and 45˚ inclined CFRP sheets, has not clearly explained. An experimental program is proposed in this paper to investigate the flexural behavior of RC beams strengthened with CFRP sheets. CFRP sheets were epoxy bonded to the tension face to enhance the flexural strength of beams inducing different orientation angles of 0˚, 45˚, 60˚ and 90˚ with the beam longitudinal axis. The study shows that strengthening RC beams with CFRP sheets is highly influenced by the orientation angle of the sheets. The orientation angle plays a key role in changing the crack pattern and hence the failure mode. The influence of CFRP sheets was adequate on increasing the flexural strength of RC beams but the ductility of the beams was reduced. The best performance was obtained when strengthening RC beam obliquely using 45˚ inclined CFRP sheets where the specimen experienced additional deflection and strength of 56% and 12% respectively and the reduction in its ductility was the least. It is recom-mended to strengthen RC beams, which are weak in flexure, using 45˚ inclined CFRP sheets.  

Comparative study on the flexural strengthening of RC beams using EB CFRP sheets, NSM CFRP bars, P-SWRs, and their combinations

2020 ◽  
pp. 136943322097172
Author(s):  
Yihua Zeng ◽  
Xinghua Li ◽  
Amira Hamdy Ali Ahmed ◽  
Gang Wu
Keyword(s):  
Steel Wire ◽  
Experimental Investigations ◽  
Near Surface ◽  
Flexural Strengthening ◽  
Wire Ropes ◽  
Cfrp Sheets ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Strengthening Technique ◽  
Space Requirements

The externally bonded (EB) carbon fiber reinforced polymer (CFRP), near-surface-mounted (NSM) CFRP and the prestressed steel wire ropes (P-SWRs) has been proven to be feasible and reliable flexural strengthening methods for concrete structures. However, debonding issues in EB CFRP sheets (or NSM CFRP bars) and space requirements for edge and spacing clearance of NSM CFRP bars (or P-SWRs) has limited the application of these three strengthening techniques. Therefore, the combinations of these methods need to be investigated and clarified. In this paper, experimental investigations on the flexural performances of seven concrete beams are presented, in which three of the beams were separately strengthened with EB CFRP sheets, NSM CFRP bars, and P-SWRs, respectively, and three of the beams were combinedly strengthened with two of the three techniques. Test results demonstrated that the flexural performances of beams strengthened with the combination with EB CFRP sheets, NSM CFRP bars, and P-SWRs are between the flexural performances of the beams strengthened with the corresponding individual strengthening techniques. It is found that the P-SWRs is favorable for combinations. In case the P-SWRs was combined with EB CFRP sheets or NSM CFRP bars for strengthening, the cracking load was increased to more than 230% and the maximum ultimate load-bearing capacity was increased to 150% when compared with the control beam. The debonding which occurred more or less in the beams strengthened with EB CFRP sheets or NSM CFRP bars or their combination was successfully eliminated by using the combination strengthening technique with P-SWRs. Also, the combination of P-SWRs with EB CFRP sheets or NSM CFRP bars is also favorable to improve the ductility of strengthened beams.

Experimental Research and Principle on Strengthened T-Beam with External Pre-Stressed Variable Section CFRP Sheets Based on Moment

2014 ◽  
Vol 1030-1032 ◽  
pp. 774-780
Author(s):  
Xiao Ying Chen ◽  
Jing Zhuo ◽  
Tang Ning Li
Keyword(s):  
Multiple Point ◽  
Test Results ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Strength Capacity ◽  
Cfrp Sheet ◽  
T Beam ◽  
Two Sides ◽  
Frp Sheet ◽  
Strengthening Method

An innovative external pre-stressed strengthening method, in which FRP (fiber reinforced polymer) sheet is placed outside of the concrete section and anchored in multiple-point, is based on moment of beam to change the area of section of FRP sheet along the length of beam. This strengthening method is that two ends of FRP sheet are first anchored by tightening WSGA (Wave-shaped-gear-anchor), then the FRP sheet is tensioned by tightening WSGG (Wave-shaped-gear-grip) on the middle of FRP sheet and accordingly pre-stressing force is built in FRP sheet. Two same 7m long reinforced concrete T-beams are strengthened at two sides of the beam with above strengthen technique, another same beam is strengthened with sticking CFRP sheet strengthen technique. Test results of strengthen beams indicate that this innovative external pre-stressed CFRP sheets strengthen technique could significantly improve the cracking load, yield load, ultimate load and stiffness of RC beams. The width of flexural cracks in concrete beams is effectively controlled and the strength capacity of the CFRP sheets is exploited.

scholarly journals Trial Think About on Flexural Quality of Fortified Solid Pillars Remotely Reinforced with CFRP Sheets

2019 ◽  
Vol 8 (9S3) ◽  
pp. 911-914
Keyword(s):  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Control Beam ◽  
Flexural Strengthening ◽  
Cfrp Sheets ◽  
Test Information ◽  
Reinforced Polymer ◽  
And Control

Fiber Reinforced polymer are ordinarily utilized for the Strengthening of Reinforced Concrete Structures. In that CFRP assumes a crucial job in giving the quality, solidness and malleability of the Reinforced solid Structures when contrasted and different filaments like GFRP, steel and aramid strands. Concentrate on Flexural Strengthening of RC Beams with CFRP (Multiple Layers) is completed. The component of the pillar examples are 100mmx200mmx1500mm. Fortified solid pillars remotely reinforced with CFRP sheets were tried utilizing a symmetrical two point concentrated static stacking framework. Two pillars were tried for Control Beam for Flexural (FB) and two bars tried for it is preloading of 70% for FB. Furthermore, after that it is tried by CFRP base just various layers for preloading of 70% for FB. The outcome appear in expanding quality when contrasted with preloading of 70% for FB. Test information on burden, diversion and extreme heap of every one of the pillar were acquired. The heap versus avoidance bends were contrasted and Control Beam for Flexural (FB), Preloading 70%FB and tried CFRP base numerous layer for preloading of 70% for FB. In this examination (CFRP) Carbon Fiber Reinforced Polymer gives apparent quality, solidness and malleability in flexure

Flexural-Torsional Buckling of Pultruded Fiber-Reinforced Polymer Angle Beams under Eccentric Loading

2020 ◽  
Vol 982 ◽  
pp. 201-206
Author(s):  
Jaksada Thumrongvut ◽  
Natthawat Pakwan ◽  
Samaporn Krathumklang
Keyword(s):  
Buckling Load ◽  
Fiber Reinforced Polymer ◽  
Width Ratio ◽  
Fiber Reinforced ◽  
Torsional Buckling ◽  
Eccentric Load ◽  
Buckling Loads ◽  
Reinforced Polymer ◽  
Cross Sectional Dimension ◽  
Flexural Torsional Buckling

In this paper, the experimental study on the pultruded fiber-reinforced polymer (pultruded FRP) angle beams subjected to transversely eccentric load are presented. A summary of critical buckling load and buckling behavior for full-scale flexure tests with various span-to-width ratios (L/b) and eccentricities are investigated, and typical failure mode are identified. Three-point flexure tests of 50 pultruded FRP angle beams are performed. The E-glass fibre/polyester resin angle specimens are tested to examine the effect of span-to-width ratio of the beams on the buckling responses and critical buckling loads. The angle specimens have the cross-sectional dimension of 76x6.4 mm with span-to-width ratios, ranging from 20 to 40. Also, four different eccentricities are investigated, ranging from 0 to ±2e. Eccentric loads are applied below the horizontal flange in increments until beam buckling occurred. Based upon the results of this study, it is found that the load and mid-span vertical deflection relationships of the angle beams are linear up to the failure. In contrast, the load and mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. The eccentrically loaded specimens are failed at critical buckling loads lower than their concentric counterparts. Also, the quantity of eccentricity increases as buckling load decreases. In addition, it is noticed that span-to-width ratio increases, the buckling load is decreased. The eccentric location proved to have considerable influence over the buckling load of the pultruded FRP angle beams.

scholarly journals Strength of RC Beam using Geopolymer Concrete and Adopting Bubble Technology

2021 ◽  
Vol 9 (VI) ◽  
pp. 2812-2816
Author(s):  
Abhinay I. Deshmukh
Keyword(s):  
Hollow Spheres ◽  
Experimental Investigations ◽  
Geopolymer Concrete ◽  
Tension Zone ◽  
Portland Cement Concrete ◽  
Dead Weight ◽  
Conventional Concrete ◽  
Modes Of Failure ◽  
Calcium Silicate Hydrates ◽  
Load Carrying

The Bubble Deck technology developed in Europe makes use of high-density polyethylene hollow spheres to replace the ineffective concrete in the centre of the slab, thus decreasing the dead weight and increasing the efficiency of the floor. Concrete is good in compression and hence is more useful in the compression region than in the tension region. The reduction in concrete can be done by replacing the tension zone concrete. Keeping the same idea in mind, an attempt has been made to find out the effectiveness of plastic bubbles by replacing concrete in the tension zone of Ordinary Portland Cement Concrete (OPCC) and Geopolymer Concrete (GPC) beam. Geopolymer Concrete does not form calcium- silicate-hydrates (CSHs) for matrix formation and strength like OPCC but utilizes the polycondensation of silica and alumina precursors to attain structural strength. In this project, M25 concrete mix is used to prepare both OPCC and GPC beams. The trial mix is tested for compressive strength. Flexure test is done is done for 28 days of curing of the beams. This paper presents the results of the experimental investigations carried out to determine and to compare the flexural behaviour of geopolymer concrete (GPC) beams with conventional concrete beams of same grade. The beams were tested under two point monotonic loading. Performance aspects such as load carrying capacity, first crack load, ultimate load, load-deflection behaviour, moment-curvature behaviour, crack width, crack spacing and the modes of failure of both types of beams were studied. The test results showed that the geopolymer concrete exhibits better performance compared to conventional concrete of same grade.

scholarly journals Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
N. Aravind ◽  
Amiya K. Samanta ◽  
Dilip Kr. Singha Roy ◽  
Joseph V. Thanikal
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Fiber Reinforced Polymer ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Glass Fiber Reinforced Polymer ◽  
Flexural Strengthening ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Load Carrying

AbstractStrengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

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