scholarly journals Advancements in shear strengthening of prestressed concrete I-girders using fiber reinforced polymers

2021 ◽  
Author(s):  
Muhammad Arslan Yaqub ◽  
Stijn Matthys ◽  
Christoph Czaderski
Keyword(s):  
Prestressed Concrete ◽  
Failure Modes ◽  
Rational Solution ◽  
Fiber Reinforced Polymers ◽  
Shear Reinforcement ◽  
Shear Strengthening ◽  
Reinforced Polymers ◽  
The Past ◽  
Externally Bonded ◽  
Fibre Reinforced Polymer

<p>A number of attempts were made by different researchers in the last couple of decades to strengthen prestressed concrete (PC) I-girders in shear using externally bonded FRP (fibre reinforced polymer) reinforcement. The unanimous observation reported in the literature is the early debonding of FRP shear reinforcement around the internal angles of the I-section. Because of this undesirable phenomenon, the strength of the FRP is utilized inefficiently. This paper gives an overview of the techniques utilized in the past and their relative performance in order to develop a rational solution to the debonding problem, particularly for I-sections. The anchoring techniques used in the past includes different types of FRP anchors as well as mechanical anchors to protect FRP shear reinforcement from debonding on the I-section. It can be concluded that the definite solution to the debonding problem on I-sections has not been obtained yet. This is because of the complex failure modes of FRP shear reinforcement and PC I-girders.</p>

scholarly journals Behavior and Analysis of Self-Consolidated Reinforced Concrete Deep Beams Strengthened in Shear

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Kh. M. Heiza ◽  
N. N. Meleka ◽  
N. Y. Elwkad
Keyword(s):  
Load Capacity ◽  
Fiber Reinforced Polymers ◽  
New Technique ◽  
Deep Beams ◽  
Carbon Fiber Reinforced Polymers ◽  
Shear Strengthening ◽  
Reinforced Polymers ◽  
Near Surface ◽  
Externally Bonded ◽  
Strengthening Technique

In this study, a new shear strengthening technique for reinforced self-compacting concrete (RSCC) deep beams was suggested and compared with some traditional techniques. An experimental test program consists of sixteen specimens of RSCC deep beams strengthened by different materials such as steel, glass, and carbon fiber reinforced polymers (GFRP and CFRP) was executed. Externally bonded layers (EBLs) and near-surface mounted reinforcement (NSMR) were used as two different techniques. The effects of the new technique which depends on using intertwined roving NSM GFRP rods saturated with epoxy were compared with the other models. The new technique for shear strengthening increases the load capacity from 36% to 55% depending on the anchorage length of GFRP rods. Two-dimensional nonlinear isoperimetric degenerated layered finite elements (FEs) analysis was used to represent the SCC, reinforcement, and strengthening layers of the tested models. The analytical results have been very close to the experimental results.

FINITE ELEMENT MODELLING OF 2-SPAN CONTINUOUS RC BEAMS SHEAR STRENGTHENED AND SHEAR REPAIRED WITH CFRP STRIPS

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Abdul Aziz Abdul Samad ◽  
Noorwirdawati Ali ◽  
Noridah Mohamad ◽  
J. Jayaprakash ◽  
Tuan Duc Ngo ◽  
...  
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Shear Behaviour ◽  
Rc Beams ◽  
Shear Strengthening ◽  
Existing Structures ◽  
Finite Element Software ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

Strengthening of reinforced concrete (RC) continuous beams in shear have received very little attention among researchers even though most existing structures are in the form of continuous condition such as part of a floor-beam system. Therefore, in order to address the gap, a study on shear strengthening and shear repair of reinforced concrete continuous beam using Carbon Fibre Reinforced Polymer (CFRP) strips was conducted [15].  The validation of the experimental results was conducted with a simulation study using a finite element software ATENA v4 [16].  The research variables were number of layers of CFRP strips (one or two layers), wrapping schemes (four sides or three sides) and orientation of CFRP strips (0/90 or 45/135 degree’s). From the analysis of the finite element results, ATENA shows it has successfully simulated the shear behaviour of strengthened and repaired of 2-span continuous RC beams externally bonded by CFRP strips. 

Shear Behavior of Rectangular Beams Strengthened with either Carbon or Steel Fiber Reinforced Polymers

2011 ◽  
Vol 82 ◽  
pp. 571-576 ◽  
Author(s):  
G.C. Manos ◽  
Konstantinos Katakalos ◽  
Christos G. Papakonstantinou
Keyword(s):  
Shear Strength ◽  
Shear Failure ◽  
Cost Effective ◽  
Shear Capacity ◽  
Polymer Materials ◽  
Fiber Reinforced Polymers ◽  
Tensile Fracture ◽  
Fiber Reinforced ◽  
Shear Strengthening ◽  
Reinforced Polymers

The aim of this study is to upgrade the shear capacity of reinforced concrete (R/C) beams strengthened with either Carbon (CFRP) or Steel (SRP) fiber Reinforced Polymers with strips having the form of either closed or open hoop external transverse reinforcement. This investigation also includes the use an anchoring device. Seven prototype specimens in need of shear strength upgrade were tested having a span of 3000mm. The strengthened R/C beams along with a non-strengthened control R/C beams were tested monotonically under four point bending loading conditions. The experimental results indicate that the shear failure of the closed hoop strengthened beams is accompanied with the tensile fracture of the CFRP/SRP strips together with an increase in the shear capacity. A considerable increase in the shear strength was observed when open hoop CFRP/SRP strips with no anchoring were used; however, the debonding of these strips posed a limitation to this upgrade. When these open hoop CFRP/SRP strips were provided with anchoring devices the shear strength of the R/C beams was further increased and the shear failure was accompanied this time by either the fracture of the CFRP/SRP strips or the failure of the anchoring system. In conclusion, a shear strengthening system for R/C beams utilizing open hoop CFRP/SRP strips with properly designed anchoring it is easily applicable, it increases significantly the shear capacity of such R/C beams and it exploits at the same time the high tensile strength of these fiber polymer materials in a cost effective way. An analytical procedure used to predict the shear strength for of such R/C beams yielded good comparison with the measured values.

scholarly journals Interaction between Internal Shear Reinforcement and External FRP Systems of RC Beams: Experimental Study

2017 ◽  
Vol 11 (1) ◽  
pp. 143-152
Author(s):  
Wee Teo ◽  
Kilian Lau Meow Hing ◽  
Mohd Shahir Liew
Keyword(s):  
Concrete Beams ◽  
Research Effort ◽  
Shear Resistance ◽  
Rc Beams ◽  
Shear Reinforcement ◽  
Shear Strengthening ◽  
Modes Of Failure ◽  
Externally Bonded ◽  
Good Agreement ◽  
Do So

Extensive research effort has been conducted on the shear strengthening of reinforced concrete (RC) beams with externally bonded FRP systems. However, there are still few aspects on their behaviour that are yet to be fully understood. One of them is the effect of shear interaction between internal transverse shear reinforcement and the external FRP systems. This paper is intended to study experimentally the interaction between these two shear reinforcement components. To do so, a total of five concrete beams were assembled in this investigation. All beams were properly instrumented in order to obtain as much data as possible. Four beams were externally strengthened with FRP with different strengthening and wrapping schemes. Their influence and interaction with the internal transverse stirrups in shear resistance were discussed based on the modes of failure exhibited, deflection and strain (steel and FRP) responses. Overall the results obtained are in good agreement with many researches which indicated that addition of externally bonded FRP, as a matter of fact, preserves the integrity of internal transverse stirrups. With continuous FRP sheets and U-wrapped scheme, greater FRP contribution to the shear resistance can be expected.

scholarly journals SEISMIC RETROFITTING OF REINFORCED CONCRETE SHEAR WALL USING CARBON FIBER REINFORCED POLYMERS (CFRP)

2020 ◽  
Vol 15 (12) ◽  
Author(s):  
Shahzad Khan
Keyword(s):  
Shear Wall ◽  
Seismic Retrofitting ◽  
Fiber Reinforced Polymers ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Before And After ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Constant Axial Load

In this paper, the experimental results of a partially retrofitted non-compliant with code concrete shear wall using uni-directional carbon fibre reinforced polymer (CFRP) are introduced. The common deficiencies in the wall were insufficient reinforcement, un-confinement at boundary zone, the lake of in-plane stiffness, and ductility. The adopted retrofitting technique consists of the CFRP strips bonded to both wall face with mesh anchors installed in the wall panel and foundation to avoid debonding. The wall was tested before and after retrofitting under a constant axial load, and the displacement control lateral cyclic load was applied to the head beam level. The retrofitted wall showed satisfactory results in terms of drift and shear strength. The test results include the failure pattern, load-displacement behaviours, and deflected shape.

scholarly journals Behaviour of Segmental Concrete Beams Reinforced by Pultruded CFRP Plates: An Experimental Study

2019 ◽  
Vol 25 (8) ◽  
pp. 62-79 ◽  
Author(s):  
Ali Adel Abdulhameed ◽  
AbdulMuttalib Issa Said
Keyword(s):  
Carbon Fiber ◽  
Design Procedure ◽  
Interface Condition ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Externally Bonded ◽  
Design Values ◽  
Carbon Fiber Reinforced

The research aims to develop an innovative technique for segmental beam fabrication using plain concrete blocks and externally bonded Carbon Fiber Reinforced Polymers Laminates (CFRP) as a main flexural reinforcement. Six beams designed and tested under two-point loadings. Several parameters included in the fabrication of segmental beam were studied such as; bonding length of carbon fiber reinforced polymers, the surface-to-surface condition of concrete segments, interface condition of the bonding surface and thickness of epoxy resin layers. Test results of the segmental beams specimens compared with that gained from testing reinforced concrete beam have similar dimensions for validations. The results display the effectiveness of the developed fabrication method of segmental beams. The modified design procedure for externally bonded carbon fiber reinforced polymers ACI 440.2R-17 was developed for designing segmental beams. The experimental test values also compared with design values, and it was 93.3% and 105.8% of the design values, which indicates the effectiveness of the developed procedure.  

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