Flexural Reinforcement of Autoclaved Aerated Concrete (AAC) with externally bonded Carbon Fiber-Reinforced Polymer (FRP) Sheet

2007 ◽  
Vol 4 (2) ◽  
Author(s):  
Nasim Uddin ◽  
Kedar V. Shelar
Keyword(s):  
Carbon Fiber ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Autoclaved Aerated Concrete ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Aerated Concrete ◽  
Flexural Reinforcement ◽  
Frp Sheet

Externally bonded carbon fiber–reinforced polymer composites for seismic retrofit of reinforced concrete coupling beams designed according to old codes

2018 ◽  
Vol 22 (6) ◽  
pp. 1412-1425 ◽  
Author(s):  
Sara Honarparast ◽  
Georges El-Saikaly ◽  
Omar Chaallal
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Polymer Composites ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Externally Bonded ◽  
Carbon Fiber Reinforced

A large number of existing buildings have seismic-resistant systems designed according to old code provisions. These structural systems exhibit non-ductile behavior and can present a significant risk in the case of a moderate or significant seismic event. Reinforced concrete–coupled shear walls designed to old codes and standards are among those deficient structures that need to be seismically upgraded. This article aims to investigate a new retrofitting and upgrading method using externally bonded carbon fiber–reinforced polymer composites for existing or/and damaged reinforced concrete coupling beams that can improve the seismic performance of them during earthquakes. To this end, an experimental test was conducted to evaluate the seismic behavior of two identical reinforced concrete–coupled shear wall specimens under reverse cyclic loading. To simulate the old existing building, the specimens were designed and constructed according to the old 1941 National Building Code of Canada with a conventionally reinforced coupling beam. One of the specimens was tested as a control, and the other was strengthened using externally bonded carbon fiber–reinforced polymer composites to evaluate the improvement in its seismic performance. Results show that the retrofit using externally bonded carbon fiber–reinforced polymer resulted in significant enhancement in strength and energy dissipation capacity compared to the conventionally reinforced coupling beam from the control specimen. In addition, externally bonded carbon fiber–reinforced polymer sheets resulted in much improved hysteretic and ductile behavior and in lesser strength and stiffness degradation.

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.

Optimum Design of Carbon Fiber-Reinforced Polymer for Increasing Shear Capacity of Beams

2020 ◽  
pp. 183-194
Keyword(s):  
Carbon Fiber ◽  
Optimum Design ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Rc Structures ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Carbon Fiber Reinforced

For reinforced concrete (RC) structures, retrofit of structures are needed to be done for several situations. These situations include the renovation of structure by adding new components (floors or extension) and elimination of safety risks (resulting from unforeseen effects - forces and durability). Most retrofit methods for RC structures need destruction of existing members and hard work on increasing of existing section dimension and reinforcements. Whereas, using carbon fiber reinforced polymer (CFRP) strips is an easy option to increase the flexural moment or shear capacity of RC members without destruction. In that case, the use of the structure is provided during the application. In this chapter, the optimum design of CFRP strips is presented for increasing the insufficient shear capacity of RC beams. The design constraints are provided according to ACI-318: Building code requirements for structural concrete and ACI-440: Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structure.

Experimental study on the behavior of thermally insulated RC beams strengthened with CFRP after their exposure to high temperatures compared to non- insulated ones

2020 ◽  
Vol 47 (7) ◽  
pp. 875-883 ◽  
Author(s):  
A. Zarifian ◽  
R.A. Izadi fard ◽  
A. Khalighi
Keyword(s):  
Carbon Fiber ◽  
High Temperatures ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Reinforcement System ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Weak Points

With regard to the expansion of the use of carbon fiber reinforced polymer (CFRP) in strengthening civil engineering structures due to its high positive points (like high tensile strength and low thickness) as well as its weaknesses in high temperatures especially in buildings and weak points of existing thermal insulators, the experiments mentioned in this article have been carried out to investigate the post-fire conditions of CFRP retrofitting systems using the externally bonded reinforcement technique which resulted from the need to use insulation for this type of reinforcement system to improve its heat performance, as well as the weak points of common insulations. In the first phase, 12 samples of reinforced concrete (RC) beams strengthened with externally bonded carbon fiber reinforced polymer (UD200) were heated at 400 °C, 500 °C, 600 °C, and 800 °C and loaded after cooling, then they were compared with the results of the second phase of the tests which have been explained completely, consisting of 11 RC beams strengthened with CFRP having exactly the same properties as those in the first phase. They were also thermally insulated with intumescent paint that had some advantages like low thickness (1.1 mm) and the speed and ease of implementation and restoration. These results have clearly shown that the new insulating layer not only can maintain the positive feature of common insulations, but also unlike other common insulators, does not add to the thickness of the specimens. Moreover, the application of the intumescent paint both increased the performance of the specimens at high temperatures and covered the weaknesses of CFRP reinforcement system against heat so that the CFRP sheets unlike the ones on the non-insulated specimens did not completely disappear at the highest temperature.

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