FRCM SHEAR STRENGTHENING FOR CONCRETE BEAMS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Adel Younis ◽  
Usama Ebead ◽  
Kshitij C. Shrestha
Keyword(s):  
Shear Zone ◽  
Carbon Fibers ◽  
Shear Failure ◽  
Load Capacity ◽  
Full Length ◽  
Rc Beams ◽  
Test Results ◽  
Shear Strengthening ◽  
Strength Enhancement ◽  
Fabric Reinforced Cementitious Matrix

This paper presents the results of an experimental study carried out to examine the efficacy of Fabric-Reinforced Cementitious Matrix (FRCM) in strengthening RC beams susceptible to shear failure. In this paper, seven shear-critical RC beams, of 2,500 mm in length, 150 mm in width, and 330 mm in depth, were tested under three-point loading until failure. Two main test variables were considered, which are: a) Strengthening material: carbon, polyparaphenylene benzobisoxazole (PBO), or glass FRCM, and b) Strengthening application pattern: a single full-length FRCM plate or a set of intermittent and spaced FRCM strips were applied along the critical shear zone. The test results confirmed the efficacy of FRCM strengthening in improving the load capacity of shear-critical RC beams. The FRCM-strengthening contributed to increases in the load capacity ranged between 31% and 100% compared to the reference specimen. The full-length strengthened specimens generally showed a better strength enhancement compared to the intermittent counterparts when using the same FRCM material. Such intuitive observation assures the importance of the amount of strengthening material applied in the critical shear zone. Besides, specimens utilizing carbon fibers in its FRCM strengthening material showed the highest strength enhancement among the three systems.

BOND AND SHEAR-STRENGTHENING PERFORMANCE OF FRCM COMPOSITES

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Adel Younis ◽  
Usama Ebead
Keyword(s):  
Rc Beam ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Test Results ◽  
Shear Strengthening ◽  
Double Shear ◽  
Structural Improvement ◽  
Load Carrying ◽  
Double Shear Test ◽  
Fabric Reinforced Cementitious Matrix

This paper is aimed at studying the bond and shear-strengthening performance of fabric reinforced cementitious matrix (FRCM) systems. Three FRCM systems were compared, namely, polyparaphenylene benzobisoxazole (PBO)-FRCM, Carbon-FRCM, and Glass-FRCM. At first, six double-shear specimens were tested to investigate the FRCM/concrete bond, with the test variables including the fabric type and the bond length. After that, seven shear-critical reinforced concrete (RC) beams were tested under three-point loading, considering the fabric type and strengthening configuration (full/intermittent) as the test variables. As for the double-shear test results, the failure observed was fabric/matrix debonding in carbon-FRCM, matrix/concrete debonding in PBO-FRCM, and fabric rapture in glass-FRCM. The FRCM/concrete bond increased with the bonded length, and the PBO-FRCM showed the highest bond to concrete. Regarding the RC beam tests, the FRCM-strengthened beams showed the same failure mode that is debonding at the FRCM/concrete interface. Nonetheless, FRCM had successfully strengthened the beams in shear: an average gain of 57% in the load carrying capacity was achieved as compared to the non-strengthened reference. Indeed, the full-length strengthening resulted in a better structural improvement compared to the intermittent-strengthening configuration. Amongst the three systems, carbon-FRCM systems were the most efficient in shear-strengthening RC beams.

scholarly journals Characterization and application of FRCM as a strengthening material for shear-critical RC beams

2018 ◽  
Vol 199 ◽  
pp. 09004
Author(s):  
Adel Younis ◽  
Usama Ebead
Keyword(s):  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Shear Strengthening ◽  
Structural Capacity ◽  
Test Parameters ◽  
Study Results ◽  
Glass Carbon ◽  
Characterization Test ◽  
Fabric Reinforced Cementitious Matrix

This paper investigates the effectiveness of fabric reinforced cementitious matrix (FRCM) systems in shear-strengthening of reinforced concrete beams. Three types of FRCM systems were considered, namely, polyparaphenylene benzobisoxazole (PBO)-FRCM, Carbon-FRCM, and Glass-FRCM. At first, tensile characterization test was performed on 15 FRCM coupons with the aim of identifying the tensile properties of the FRCM systems adopted. After that, seven shear-critical RC beams were tested under three-point loading, with the consideration of two test parameters: (a) FRCM material (glass/carbon/PBO); and (b) strengthening configuration (full/intermittent). The study results revealed the use of FRCM as a strengthening material to achieve a considerable improvement in the structural capacity of shear-critical RC beams. The average gain in the shear capacity of the FRCM-strengthened beams was 57%. The beam specimens strengthened with carbon-FRCM showed the highest improvement as compared to those strengthened with glass-and PBO-FRCM systems. As intuitively expected, the shear capacity improvement achieved with the full-length strengthening systems was generally higher than that with the intermittent counterparts.

scholarly journals Embedded Connector in Severe Optimization of Steel Plate for Shear Strengthening of RC Beam: Experimental and Numerical Investigations

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Md. Ashraful Alam ◽  
Suliman A. Bakkar ◽  
Shahnawaz A. Onik ◽  
Kamal N. Mustapha
Keyword(s):  
Shear Failure ◽  
Steel Plate ◽  
Maximum Load ◽  
Rc Beams ◽  
Reinforced Concrete Structure ◽  
Shear Strengthening ◽  
Maximum Increase ◽  
Numerical Investigations ◽  
Externally Bonded ◽  
Major Factors

Environmental impact has become one of the major factors taken into consideration for recent civil engineering studies and projects. Thus, researchers have been concentrating on shear strengthening of existing reinforced concrete structure as an upgrade method instead of demolishing and reconstructing. In general, shear strengthening of RC beams using externally bonded steel plate has gained huge popularity. However, premature debonding of plates is the main drawback of the system, which could be mitigated using embedded connector; thus, the dimension of steel plate could be reduced significantly. Furthermore, numerical analysis on shear strengthening of beams using embedded connector would provide a great insight on the structural behavior. The aim of this research is to severely reduce the dimension of the steel plate using embedded connector for shear strengthening of RC beams and to investigate the performances of optimized shear-strengthened beams through experimental and numerical investigations. The results showed that the dimension of plate was reduced without debonding of the plate if the beam was designed for shear strengthening with the consideration of yield strength of steel plate and shear link. Experimental results showed a maximum increase in failure of 24%. The numerical results predicted accurately the structural performance of beams. The embedded connector had a great effect in deferring and minimizing the debonding failure and accordingly increasing the maximum load of shear failure between 14.5% and 24% compared to control beam.

scholarly journals Prediction of Flexural Capacity of RC Beams Strengthened in Flexure with FRP Fabric and Cementitious Matrix

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Kyusan Jung ◽  
Kinam Hong ◽  
Sanghoon Han ◽  
Jaekyu Park ◽  
Jaehyun Kim
Keyword(s):  
Bond Strength ◽  
Strength Model ◽  
Rc Beams ◽  
Test Results ◽  
Flexural Capacity ◽  
Cementitious Matrix ◽  
Analytical Research ◽  
Fabric Reinforced Cementitious Matrix ◽  
Test Database ◽  
Strengthening Method

This paper presents both experimental and analytical research results for predicting the flexural capacity of reinforced concrete (RC) beams strengthened in flexure with fabric reinforced cementitious matrix (FRCM). In order to assess the efficiency of the FRCM-strengthening method, six beams were strengthened in flexure with FRCM composite having different amounts and layers of FRP fabric and were tested under four-point loading. From test results, it was confirmed that the slippage between the FRP fabric and matrix occurs at a high strain level, and all of the FRCM-strengthened beams failed by the debonding of the FRCM. Additionally, a new bond strength model for FRCM considering the slippage between fabric and matrix was proposed, using a test database to predict the strengthening performance of the FRCM composite. The prediction of the proposed bond strength model agreed well with the debonding loads of the test database.

scholarly journals SHEAR STRENGTHENING OF REINFORCED CONCRETE BEAM USING EXTERNALLY STRIRRUPS

2019 ◽  
Vol 3 (2) ◽  
pp. 105
Author(s):  
Arga Saputra ◽  
Sri Murni Dewi ◽  
Lilya Susanti
Keyword(s):  
Concrete Beam ◽  
Shear Failure ◽  
Reinforced Concrete Beam ◽  
Shear Capacity ◽  
Crack Pattern ◽  
Test Results ◽  
Shear Cracks ◽  
Shear Strengthening ◽  
Shear Area ◽  
Calculation Analysis

Initial design errors, especially the installation of stirrups, one of them can cause the beam having shear failure due to installing capacity of stirrups less than the shear capacity that occurs. Shear strengthening in this study used externally stirrups ∅6-75 which were installed in the shear area only. The results of calculation analysis, shear capacity can increase up to 137.82%; 133.42% and 137.12% while the test results increased by 31.58%; 0% and 4.76% in this caseload did not look significant from the results of calculation analysis. However, when viewed from crack pattern that occurs without external stirrups, outer ring has a combination of flexural and shear cracks occurs quite much, besides of flexural and shear cracks, combination of crack also occurs because of pressure beam reach pressure capacity first rather than tensile beam because the ratio of installed reinforcement is over reinforced. Meanwhile, in the beam with external stirrups, the crack pattern that occurs is also a combination of bending and shear cracks, but the cracks that occur are relatively less than the beam without external stirrups. When viewed from the deflection that occurred during the first crack, the reinforced beam experienced a relatively smaller deflection of 0.61 mm beam; 0.31 mm and 0.18 mm rather than beams without externally stirrups 1.28 mm; 0.55 mm and 0.32 mm, so that the beam with external stirrups can be said to be more rigid than the beam without external stirrups. Kesalahan desain awal, khususnya pemasangan sengkang, salah satunya dapat mengakibatkan balok mengalami kegagalan geser akibat kapasitas sengkang yang terpasang kurang dari kapasitas geser yang terjadi. Perkuatan geser pada penelitian ini menggunakan sengkang ∅6-75 yang dipasang pada daerah geser saja. Hasil dari perhitungan analisis, kapasitas geser dapat meningkat sampai 137,82%; 133,42% dan 137,12% sedangkan dari hasil pengujian mengalami peningkatan sebesar 31,58%; 0% dan 4,76% dalam hal ini peningkatan beban tidak terlihat sesignifikan dari hasil analisis perhitungan, namun jika dilihat dari pola retak yang terjadi beton tanpa perkuatan sengkang luar mengalami kombinasi retak lentur dan geser yang cukup banyak, selain kombinasi retak lentur dan geser, juga terjadi retak akibat balok tekan yang mencapai kapasitas tekan terlebih dahulu daripada balok tarik karena rasio tulangan yang terpasang over reinforced. Sementara itu pada balok dengan perkuatan sengkang luar, pola retak yang terjadi juga kombinasi retak lentur dan retak geser, namun retak yang terjadi relatif lebih sedikit daripada balok tanpa perkuatan. Jika ditinjau dari lendutan yang terjadi pada saat crack pertama, balok yang diberi perkuatan mengalami lendutan yang relatif lebih kecil yaitu 0,61 mm; 0,31 mm dan 0,18 mm daripada balok tanpa perkuatan 1,28 mm; 0,55 mm dan 0,32 mm sehingga balok yang diperkuat dengan sengkang luar dapat dikatakan lebih kaku daripada balok tanpa perkuatan.

Shear Behaviour of RC Beams Strengthened with FRP Materials

2012 ◽  
Vol 463-464 ◽  
pp. 249-253
Author(s):  
Jiang Feng Dong ◽  
Dong He ◽  
Shu Cheng Yuan ◽  
Qing Yuan Wang
Keyword(s):  
Concrete Strength ◽  
Research Work ◽  
Shear Behaviour ◽  
Rc Beams ◽  
Test Results ◽  
Shear Strengthening ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Glass Frp

This paper reports the results of a research work aimed at examining the use of externally bonded of fiber reinforced polymer (FRP) sheets, consisting of carbon FRP (CFRP) and glass FRP (GFRP), as a strengthening solution to upgrade the shear capacities of reinforced concrete (RC) beams. A total of 7 RC beams were constructed and tested under four-point bending, i.e. two reference beams with different concrete strength and without any FRP sheets, one beam reinforced by GFRP sheets and four beams reinforced by CFRP sheets. Externally bonded FRP shear strengthening was found very effective in upgrading the shear strength of the beams strengthened. The shear strengths of RC beams strengthened were improved greatly by FRP sheets, and the strength gain caused by the FRP sheets was in the range of 31-74%. Test results also show that the more ductile behaviour and higher ultimate strength are obtained for the beams with FRP shear strengthening by using high concrete strength.

Shear Resistance of RC Beams Strengthened with Combined CFRP and Steel Plate

2014 ◽  
Vol 638-640 ◽  
pp. 219-223
Author(s):  
Yi Yan Lu ◽  
Na Li ◽  
Shan Li
Keyword(s):  
Shear Failure ◽  
Steel Plate ◽  
Shear Resistance ◽  
Steel Plates ◽  
Rc Beams ◽  
Test Results ◽  
Simultaneous Application ◽  
Cfrp Sheets ◽  
Shear Performance ◽  
Strengthening Technique

The purpose of this study is to investigate shear performance of RC beams strengthened with combined CFRP and steel plates. Fourteen beams were tested to shear failure under simply supported four-point loading conditions. The variables of this investigation included strengthening technique, shear span to depth ratio, percentage of CFRP, percentage of steel plate, CFRP and steel plate orientation, CFRP and steel plate wrapping type. The results show that the simultaneous application of CFRP sheets and steel plate greatly increases the shear resistance of RC beams. The steel plates improve the bond behavior of CFRP sheets. A design formula is proposed to calculate the shear resistance of the beams strengthened with combined CFRP sheets and steel plates. The predictions agree well with the test results.

scholarly journals Strengthening of Reinforced Concrete Continuous Beams using GFRP

2019 ◽  
Vol 9 (1) ◽  
pp. 1855-1857
Keyword(s):  
Reinforced Concrete ◽  
Static Loading ◽  
Failure Load ◽  
Load Capacity ◽  
Reference Beam ◽  
Research Paper ◽  
Rc Beams ◽  
Test Results ◽  
Continuous Beams ◽  
Deflection Analysis

This research paper gives the behaviour of reinforced concrete continuous beams under static loading by externally bonding with GFRP sheets. A standard two span continuous beams of size (300×300×2500)mm were casted. Reference beam with no external bonding is prepared to compare the values. Identical reinforcement arrangement is done for all beams. RC beams are tested for failure, load capacity and deflection analysis. Test results are compared for reference and GFRP bonded beams.

scholarly journals Influence of flange on the shear capacity of reinforced concrete beams

2018 ◽  
Vol 162 ◽  
pp. 04003
Author(s):  
Kaiss Sarsam ◽  
Raid Khalel ◽  
Nisreen Mohammed
Keyword(s):  
Structural Engineering ◽  
Shear Failure ◽  
Concrete Beams ◽  
Design Method ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Test Results ◽  
Web Reinforcement ◽  
The Web

In structural engineering (RC, steel, etc.) it is usual to base the shear strength of members on the web only- e.g. in RC the stirrups used are usually called “web reinforcement”. Presently all codes, and several researches, base the strength of members on the capacity of the web alone. 93 tests of T-beams failing in shear available from the literature are studied in this work to estimate the influence of flanges on the shear capacity of RC beams. These include 32 ones without web reinforcement and 61 with stirrups. Comparison between test results and theoretical shear capacity show that all available equations conservatively estimate the occurrence of shear failure. In this work an equation for predicting the contribution of the flange to shear capacity in T-beams is presented. The best available design method obtained from the literature leads to a coefficient of variation (COV) of 17.58% compared to 13.46% for the proposed design method in this work.

SHEAR BEHAVIOR OF RC BEAMS STRENGTHENED WITH DIFFERENT TYPES OF FRCM: EFFECT OF STIRRUPS’ CONFIGURATION

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Tadesse Wakjira ◽  
Usama Ebead
Keyword(s):  
Load Capacity ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Rc Beams ◽  
Deep Beams ◽  
Shear Strengthening ◽  
Test Variable ◽  
Rc Deep Beams ◽  
Different Types ◽  
Primary Test

Fabric-reinforced cementitious matrix, (FRCM) system has shown to be promising for the strengthening of reinforced concrete (RC) beams. However, the available experimental investigation on the shear strengthening efficacy of FRCM system is limited, particularly for deep beams. Moreover, to the authors' knowledge, no literature is available on the effect of the stirrups' configuration relative to the FRCM strips on the shear capacity of FRCM-strengthened beams. Studying this effect will aid in a better understanding of the FRCM/stirrups interaction. Thus, in this paper the experimental study on the shear behavior of RC deep beams strengthened in shear using FRCM system is presented. The test matrix involved two unstrengthened and six FRCM-strengthened deep beams tested under three-point bending. The primary test variable was the effect of stirrups' configuration relative to the FRCM strips. The other test variable includes the effect of different types of FRCM fabric (made of carbon, glass, and polyparaphenylene benzobisoxazole, PBO). Experimental results demonstrated an effective application of the FRCM in improving the load capacities of RC deep beams, up to 40.3% increase in the load capacity was achieved.

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