Rehabilitation of Continuous Reinforced Concrete Beams in Shear by External Bonding of Carbon Fiber Reinforced Polymer Strips for Sustainable Construction

2016 ◽  
Vol 708 ◽  
pp. 49-58
Author(s):  
Abdul Aziz Abdul Samad ◽  
Noridah Mohamad ◽  
Noorwirdawati Ali ◽  
J. Jayaprakash ◽  
Priyan Mendis
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Structural Integrity ◽  
Failure Load ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Shear Strengthening ◽  
Reinforced Polymer

To achieve sustainability in construction, the rehabilitation of existing concrete structures is vital in ensuring its structural integrity and longevity. Therefore, an experimental investigation on the shear strengthening of 2-span continuous reinforced concrete (RC) beams wrapped with carbon fiber reinforced polymer (CFRP) strips were conducted. The beam specimens were subjected to four point bending test and loaded incrementally until failure occurs. Different wrapping schemes and layers of CFRP strips were externally bonded within the shear span of the beams. The failure load, modes of failure, its crack patterns, deflection profile were recorded and presented for discussion. From observation, the experimental results indicated good improvement as the shear strengthened beams shows enhanced failure load and shear strength capacity. An improved stiffness and ductility behaviour was also observed compared to the control beam. Comparison with ACI 440 (2008) design provisions for shear strength shows that the prediction values underestimated its experimental results. This indicates that the enhanced shear performances of the 2-span continuous RC beams prove the reliability of CFRP as a strengthening material. Hence, the shear strengthening technique allows the rehabilitation process of existing structural members to improve its structural integrity, longevity and sustainability.

scholarly journals Strengthening of Reinforced Concrete Slab-Column Connections with Carbon Fiber Reinforced Polymer Laminates

2019 ◽  
Vol 10 (1) ◽  
pp. 265 ◽  
Author(s):  
Cheng-Chih Chen ◽  
Shun-Long Chen
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Concrete Slab ◽  
Fiber Reinforced Polymer ◽  
Punching Shear ◽  
Carbon Fiber Reinforced Polymer ◽  
Cfrp Laminates ◽  
Reinforced Polymer

This study presents the structural behavior and punching shear strength of the concrete slab-column connections strengthened with carbon fiber reinforced polymer (CFRP) laminates. The variables considered for the twelve specimens included the compressive strength of the concrete, the ratio of the tensile steel reinforcement, and the amount of the CFRP laminates. Square concrete slabs were simply supported along four edges. During the test, monotonically concentrated load was applied to the stub column located at the center of the slab. The punching shear strength, stiffness, and mode of failure were investigated. Test results demonstrated that increasing the compressive strength of concrete, ratio of the steel reinforcement, and amount of the CFRP laminates led to an increase in the punching shear strength of the slabs. Moreover, the CFRP laminates were effective in appreciably increasing the punching shear strength of the slab-column connections. An analytical approach was conducted to calculate the punching shear strength of the slab-column connections strengthened with CFRP laminates. Based on the theory of reinforced concrete members, the application of the CFRP laminates increased the flexural strength of the slab and resulted in an increase of the effective depth of the slab section. Consequently, the punching shear strength was increased. The results of the analytical calculation revealed that the analytical work accurately predicted the experimental punching shear strength.

Flexural behavior of reinforced concrete beams strengthened by carbon fiber reinforced polymer using different strengthening techniques

2021 ◽  
pp. 136943322110499
Author(s):  
Riyam J Abed ◽  
Mohammed A Mashrei ◽  
Ali A Sultan
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Control Beam ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Carbon Fiber Reinforced

The externally bonded reinforcement on grooves (EBROG) method is increasingly recognized as an alternative strengthening method that can overcome the debonding problem. This study aims to experimentally investigate the effectiveness of EBROG as compared to the conventional externally bonded reinforcement (EBR) method in strengthening reinforced concrete (RC) beams. Twelve RC beams have been tested under four point load bending. One of these beams has been designated as a reference beam, seven beams have been strengthened with carbon fiber reinforced polymer (CFRP) sheets, and four beams have been strengthened with CFRP laminates using EBROG or EBR methods. The effect of CFRP type, number of layers, as well as the type of strengthening methods on the flexural performance have been also investigated. The load, deflection, stiffness, and failure modes were recorded and discussed intensively. Overall, test results indicated that the flexural strength and stiffness of the strengthened specimens using EBR or EBROG methods increased compared to the control beam, where the increase in the load carrying capacity of beams strengthened using the EBR method ranged between 24.8 and 48.2% and by the EBROG method ranged between 31.7 and 76.7% of the control beam. The most interesting result obtained is that the failure mode of beams has been changed from debonding of CFRP material to rupture of CFRP in some samples strengthened by EBROG, which demonstrates the superior behavior of this strengthening technique as compared to the traditional strengthening using EBR.

Simulation Behavior of Flexure in Reinforced Concrete Beams Strengthened with Carbon Fiber Reinforced Polymer (CFRP)

2015 ◽  
Vol 754-755 ◽  
pp. 432-436
Author(s):  
Ibrahim H. Alfahdawi ◽  
S.A. Osman
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

When reinforced concrete (RC) beams are found deficient in flexure, and fails in shear capacity after shear strengthening, the need to use new technique for flexure strengthening become important. Over the years, there are many experimental studies had been carried out with this technique of strengthening, and finding from other researchers have proved to be effective and successful. In this study, the behavior of flexure in RC beams strengthened with carbon fiber reinforced polymer (CFRP) were investigated. ANSYS11 software package of finite element method was use to simulate two models of RC beams with different parametric study such as (i) effect of grade of concrete, (ii) number of layers of CFRP strips, (iii) effect of steel stirrups and CFRP strips and (iv) longitudinal reinforcement yield stress. The results show that for beams strengthened with CFRP has increased in capacity load up to 32.8%. In general, good agreement between the FE solution and the available experimental results has been obtained.

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