scholarly journals Shear Strengthening Performance of Hybrid FRP-FRCM

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Kyusan Jung ◽  
Kinam Hong ◽  
Sanghoon Han ◽  
Jaekyu Park ◽  
Jaehyun Kim
Keyword(s):  
Shear Capacity ◽  
Shear Strengthening ◽  
Cementitious Matrix ◽  
Reinforced Polymer ◽  
Capacity Model ◽  
Proposed Model ◽  
Externally Bonded ◽  
Strengthened Beam ◽  
Fabric Reinforced Cementitious Matrix ◽  
Glass Frp

The effectiveness of a hybrid fiber reinforced polymer- (FRP-) fabric reinforced cementitious matrix (FRCM) for shear strengthening was investigated though an experimental study. FRP materials of FRCM are usually fabricated in the form of a fabric to enhance the bond strength between the FRP material and the cementitious matrix. The hybrid FRP fabric used in this study consisted of carbon FRP (CFRP) and glass FRP (GFRP) in warp and weft directions, respectively. A total of 11 beams were fabricated and 8 beams among them were strengthened in shear with externally bonded hybrid FRP-FRCM. The number of plies, the bond types, and the spacing of the hybrid FRP fabric were considered as experimental variables. Additionally, a shear capacity model for a FRCM shear strengthened beam was proposed. The values predicted by the proposed model were compared with those by the ACI 549 code and test results. It was confirmed from the comparison that the proposed model predicted the shear strengthening performance of the hybrid FRP-FRCM more reliably than the ACI 549 code did.

Strengthening of shear deficient RC deep beams using GFRP sheets and mechanical anchors

2021 ◽  
Vol 48 (1) ◽  
pp. 1-15 ◽  
Author(s):  
A. Kumari ◽  
A.N. Nayak
Keyword(s):  
Design Guidelines ◽  
Shear Capacity ◽  
Deep Beams ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Rc Deep Beams ◽  
Externally Bonded ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Strengthened Beam

This paper presents the test results of an experimental study on shear deficient reinforced concrete (RC) deep beams strengthened with externally bonded glass fibre reinforced polymer (GFRP) sheets and mechanical anchors. A total of nine deep beams are prepared. One beam is kept as un-strengthened. Four beams are strengthened using GFRP sheets only at shear spans by varying the number of layers. The remaining four beams are strengthened using both GFRP sheets and mechanical anchors at shear spans. The shear capacity, failure mode, and deflections are studied with respect to the different strengthening techniques. The optimum enhancement in shear capacity of these beams is observed as 25.64% and 55.5% for GFRP strengthened beams and GFRP strengthened anchored beams, respectively with respect to the un-strengthened beam. Moreover, the experimental results are also compared with the results predicted from the design guidelines and models available in the literature, which shows good agreement.

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.

scholarly journals Durability of Fabric-Reinforced Cementitious Matrix (FRCM) Composites: A Review

2020 ◽  
Vol 10 (5) ◽  
pp. 1714 ◽  
Author(s):  
Karrar Al-Lami ◽  
Tommaso D’Antino ◽  
Pierluigi Colombi
Keyword(s):  
Cementitious Matrix ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Direct Tensile ◽  
Long Term Performance ◽  
Term Performance ◽  
Long Term Behavior ◽  
Fabric Reinforced Cementitious Matrix

Strengthening and rehabilitation of masonry and concrete structures by means of externally bonded fabric-reinforced cementitious matrix (FRCM) (also referred to as textile reinforced mortar (TRM)) composites was proposed as an alternative to the use of fiber-reinforced polymer (FRP) composites due to their good mechanical properties and compatibility with the substrate. However, quite limited studies are available in the literature regarding the long-term behavior of FRCM composites with respect to different environmental conditions. This paper presents a thorough review of the available researches on the long-term behavior of FRCM composites. Namely, (i) test set-ups employed to study the FRCM durability, (ii) conditioning environments adopted, and (iii) long-term performance of FRCM and its component materials (mortar and fiber textile) subjected to direct tensile and bond tests, are presented and discussed. Based on the available results, some open issues that need to be covered in future studies are pointed out.

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.

A proposed strengthening model considering interaction of concrete-stirrup-FRP system for RC beams shear-strengthened with EB-FRP sheets

2018 ◽  
Vol 37 (10) ◽  
pp. 685-700 ◽  
Author(s):  
Weiwen Li ◽  
Chengyue Hu ◽  
Zejie Pan ◽  
Wei Peng ◽  
Yong Yang ◽  
...  
Keyword(s):  
Effective Strain ◽  
Polymer System ◽  
Design Guidelines ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Externally Bonded

Many factors can affect the shear capacity of fiber-reinforced polymer in reinforced concrete beams shear-strengthened with externally bonded fiber-reinforced polymer composites. Undoubtedly, the interaction of concrete-stirrup-fiber-reinforced polymer system is one of the key factors. However, most of the existing fiber-reinforced polymer design guidelines do not take account of this important factor on predicting fiber-reinforced polymer shear capacity. This study provides an advanced strengthening model that comprehensively considers the interaction among concrete, stirrup, and fiber-reinforced polymer for calculating the fiber-reinforced polymer effective strain. The advanced strengthening model provides a more accurate prediction for the fiber-reinforced polymer shear contribution compared with existing design guidelines.

scholarly journals Punching Strengthening of Concrete Slab-column Connections Using Near Surface Mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) Bars

2020 ◽  
pp. 1-14
Author(s):  
Ahmed H. Abdel-Kareem
Keyword(s):  
Carbon Fiber ◽  
Concrete Slab ◽  
Tensile Force ◽  
Shear Capacity ◽  
Punching Shear ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Near Surface Mounted ◽  
Strengthening Technique

This paper investigates experimentally the effect of near surface mounted (NSM) carbon fiber reinforcement polymer (CFRP) bars as externally strengthening on the punching shear behavior of interior slab-column connections. Many researchers used NSM as a novel strengthening technique in various structural elements. However, the strengthening of slab-column connections using NSN is relatively new. Seven Reinforced concrete (RC) square slabs with a concentric column were tested over simply supported four sides. One control specimen was tested without strengthening, four specimens were strengthened using NSM-CFRP bar installed in pre-cut groove surrounded the column at the tension side of the slab, and two specimens were strengthened using externally bonded (EB) CFRP strips which have the same tensile force of the CFRP bars. The arrangement and the location of the strengthened materials were also test variables. The test results showed that using NSM strengthening technique significantly increased the punching shear capacity and ultimate stiffness compared to using EB strengthening technique. Where the increasing in the punching capacity and ultimate stiffness were 18% and 13-18%, respectively. Moreover, the NSM-CFRP bars greatly reduced the cracks in the punching shear zone around the columns. The measured ultimate punching shear capacity for the tested specimens showed very reasonable agreement with the calculated punching loads based on an analytical model for slab-column connections strengthened using FRP that account for its arrangement and location.  

Analysis of Columns Strengthened using Fibre Reinforced Cementitious Matrix Jackets

2021 ◽  
Vol 9 (9) ◽  
pp. 1795-1800
Author(s):  
Fathima Azad
Keyword(s):  
Steel Plates ◽  
Structural Elements ◽  
Near Surface ◽  
Rc Structures ◽  
Cementitious Matrix ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Fibre Reinforced Polymer ◽  
Near Surface Mounted ◽  
Strengthening Technique

Abstract: Maintenance, repair and strengthening of existing concrete structures, either reinforced or prestressed,are important activities of civil engineers. Nowadays different techniques are available for the strengthening. Various techniques were adopted for strengthening RC structures, namely, steel plates, external post tensioning, externally bonded Fibre-Reinforced Polymer (FRP), and near- surface-mounted FRP systems to increase shear and flexural capacity. During the last few decades, strengthening of concrete structural elements by fibre-reinforced polymer has become a widely used technique. But it has several disadvantages due to the epoxy resin like debonding of FRP from the concrete structure, unstable nature of the epoxy at higher temperatures etc. To overcome this, an upgraded system was introduced as an alternative for FRP known as Fibre Reinforced Cementitious Matrices (FRCM). The objective of this paper is to investigate the feasibility of Fibre-Reinforced Cementitious-Matrix materials as an alternative external strengthening technique for RC members. Columns with circular geometry were wrapped with different fibre materials using cementitious matrix. The analysis was done using ANSYS software. Keywords: RC columns, FRCM, Strengthening, fibre, ANSYS

scholarly journals Experimental Study on Structural Degradation of CFRP Strengthened RC Beams Subjected to Weak Interfaces

2016 ◽  
Vol 10 (1) ◽  
pp. 384-401
Author(s):  
Xiaogang Wang ◽  
Wenwu Fan ◽  
Xiangbo Du ◽  
Zhaoxin Fang
Keyword(s):  
Early Stage ◽  
Fiber Reinforced Polymer ◽  
Structural Performance ◽  
Carbon Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Shear Transfer ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Strengthened Beam ◽  
Cover Thickness

The performance of corroded reinforced concrete (RC) beams strengthened with externally bonded carbon fiber reinforced polymer (CFRP) materials may be affected by a weak interface caused either by defective bonding between the new and old concrete in the case of cover replacement or by expansive cracks in the case of direct application. To investigate this effect, thirteen strengthened beam specimens with preinstalled horizontal weak interfaces were designed and tested in monotonic bending. Through analysis of the experimental results, in terms of load deflection curves and the derived bond stress distribution, it was found that intermediate delamination was induced by the weak interfaces, which greatly impaired the integrity of the strengthening system and eventually led to CFRP integral debonding without lateral confinement. Degradation of the shear transfer ability through the interface can be expected due to interfacial weakening, increasing of the CFRP reinforcement ratio and reduction of cover thickness. Crack-induced weak interfaces caused less serious damage at the early stage but induced more dramatic degradation as cracks expanded. U-strip confinement was found to be effective in improving the structural performance of the strengthened beam and preventing CFRP integral debonding. Nevertheless, intermediate delamination cannot be prevented, increasing the risk of CFRP premature rupture and end anchorage failure.

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