scholarly journals Compressive Behaviour of RC Column with Fibre Reinforced Concrete Confined by CFRP Strips

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
A. M. Vasumathi ◽  
K. Rajkumar ◽  
G. Ganesh Prabhu
Keyword(s):  
Reinforced Concrete ◽  
Fibre Reinforced Concrete ◽  
Axial Deformation ◽  
Structural Behaviour ◽  
Deformation Control ◽  
Rc Column ◽  
Frp Composites ◽  
Externally Bonded ◽  
Earthquake Resistant Structures ◽  
Cfrp Composite

The structural application of synthetic fibre reinforced concrete (FRC) has become widespread in the construction industry in order to satisfy the requirement of the earthquake resistant structures. Research conducted so far are focused on the structural behaviour of RC column externally confined with FRP composites, while studies are needed to address the behaviour of FRP strengthened RC column fabricated using fibre reinforced concrete. With the intention that the experimental investigation was carried out to evaluate the feasibility use of CFRP composite strips in strengthening of RC column made with fibre reinforced concrete. Circular synthetic Polypropylene fibre was used in the rate of 0.50% in the volume of concrete. CFRP strips having a width of 50 mm were used to confine the column and the experimental parameters were effective spacing between the CFRP strips (20 mm and 30 mm) and the number of CFRP layers (one, two and three). The externally bonded CFRP strips counteract the lateral expansion of the concrete significantly by providing restraining effect and thus effect enhanced the stiffness of the column. The column strengthened with CFRP strips showed a maximum of 198.87% and 91.75% enhancement in axial deformation control and ultimate strength, respectively, compared to that of reference column. From the test results obtained, it is suggested that CFRP strips with the spacing of 20 mm and 30 mm can be used in strengthening of RC column made with FRC; however the column confined with 30 mm spacing provides an economical advantage compared to that of 20 mm spacing.

Numerical study of ultra-high-performance steel fibre–reinforced concrete columns under monotonic push loading

2017 ◽  
Vol 21 (8) ◽  
pp. 1234-1248 ◽  
Author(s):  
Shenchun Xu ◽  
Chengqing Wu ◽  
Zhongxian Liu ◽  
Jun Li
Keyword(s):  
Reinforced Concrete ◽  
Axial Compression ◽  
High Performance ◽  
Steel Fibre ◽  
Concrete Columns ◽  
Fibre Reinforced Concrete ◽  
Structural Behaviour ◽  
Reinforced Concrete Columns ◽  
Steel Fibre Reinforced Concrete ◽  
High Performance Steel

A finite element model is developed to investigate the behaviour of ultra-high-performance steel fibre–reinforced concrete columns under combined axial compression and horizontal monotonic push loading. The effects of steel fibre content, axial compression ratio, reinforcement ratio (or rebar ratio), stirrup ratio and shear span ratio on the structural behaviour of ultra-high-performance steel fibre–reinforced concrete columns are investigated in detail. The numerical model shows good agreement in bond–slip behaviour of specimens based on CEB model results and numerical results, and such behaviour should be taken into consideration in engineering practice. The results indicate that the developed finite element model could predict the structural behaviour and failure mode of ultra-high-performance steel fibre–reinforced concrete columns effectively. It is found that the reinforcement ratio, axial compression ratio, shear span ratio and volume fraction of steel fibre have a great influence on both the structural behaviour and failure modes of specimens.

scholarly journals Structural behaviour of ultra high performance fibre reinforced concrete composite members

2021 ◽  
Author(s):  
Luaay Hussein
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
High Performance ◽  
Composite Beams ◽  
Shear Capacity ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Structural Behaviour ◽  
Shear Connectors ◽  
High Performance Fibre

The aging and deterioration of reinforced concrete infrastructures in North America present major technical and economical challenges to infrastructure owners. To effectively address some of the challenges, there is a need to develop innovative and cost-effective systems. The main objective of this research was to develop composite members of ultra-high performance fibre reinforced concrete and normal strength concrete or high strength concrete (UHPFRC-NSC/HSC). In order to achieve this objective, the first phase of this research investigates the structural behaviour of UHPFRC with varying fibre content beams without web reinforcement. Test results indicated that the addition of 1% of steel fibres effectively improves the shear strength of UHPC beams by 77% due to the crack-bridging stress that develops across the crack surface. In the second phase, experimental studies were carried out on UHPFRC-NSC/HSC prisms and beams without stirrups to investigate the flexural and shear capacity of those composite members. Each beam specimen was designed to have the UHPFRC layer in tension and the NSC/HSC layer in compression. Additional varied parameters included fibre volume content, and shear connectors were investigated. Test results showed that the performance of the proposed composite system in terms of the flexural and shear capacity was successfully enhanced. All composite beams failed in shear at a force that is 1.6 to 2.0 times higher than that of the NSC/HSC beam's resistance. Test results showed that the effect of using HSC versus NSC in the composite beam was negligible, and the bond strength between the two concrete material layers (UHPFRC and NSC/HSC) was significantly high that the addition of shear connectors was unnecessary. In the third phase, an analytical and finite element models to predict the ultimate shear capacity of UHPFRC composite beams were proposed and validated with the experimental results. The results of the finite element analysis showed that the size effect in structures made of UHPFRC material has little influence on the shear capacity. Finally a comparison between the finite element model and the analytical model indicated that both models developed in this research are capable of predicting the shear behaviour of UHPFRC and UHPFRC-NSC/HSC beams.

scholarly journals Experimental investigation of cracking behaviour of concrete beams reinforced with steel fibres produced in Lithuania

2017 ◽  
Vol 12 (2) ◽  
pp. 82-87 ◽  
Author(s):  
Adas Meškėnas ◽  
Viktor Gribniak ◽  
Gintaris Kaklauskas ◽  
Aleksandr Sokolov ◽  
Eugenijus Gudonis ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Residual Strength ◽  
Steel Fibre ◽  
Concrete Beams ◽  
Full Scale ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Structural Behaviour ◽  
Steel Fibre Reinforced Concrete ◽  
Straightforward Application

Concrete is the most widely used material for bridge structures in Lithuania. A case study performed by the authors revealed that application of fibres might improve serviceability of such structures. However, adequacy of prediction of the post-cracking behaviour of steel fibre reinforced concrete might be insufficient. The latter issue is closely related to the assessment of the residual strength of steel fibre reinforced concrete. The residual strength, in most cases, is considered as a material property of the cracked concrete. However, in the prediction of the structural behaviour of the concrete members with bar reinforcement, a straightforward application of the residual strength values assessed by using standard techniques might lead to incorrect results. The present study deals with the post-cracking behaviour of structural elements made of concrete with aggregates and fibres provided by Lithuanian companies. Test results of three full-scale and sixteen standard steel fibre reinforced concrete beams with two different content of fibres (23.6 kg/m3 and 47.1 kg/m3) are presented. The full-scale beams were reinforced with high-grade steel bars. Effectiveness of the application of the minimum content of the fibres in combination with bar reinforcement was revealed experimentally.

scholarly journals Degradation of the EBR-CFRP strengthening system applied to reinforced concrete beams exposed to weathering

2021 ◽  
Vol 14 (2) ◽  
Author(s):  
Gláucia Maria Dalfré ◽  
Guilherme Aris Parsekian ◽  
Douglas da Costa Ferreira
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Natural Aging ◽  
Outdoor Exposure ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Externally Bonded ◽  
Cfrp Composite

Abstract Little is known about the behavior and durability of strengthening systems applied on concrete substrata and the possible loss of performance due to the degradation of the intervening materials by the structure’s natural aging process and exposure of the externally strengthened elements to aggressive environments. In this context, the present work presents an experimental analysis of the behavior of reinforced concrete beams strengthened with Carbon Fiber Reinforced Polymer (CFRP), applied according to the Externally Bonded Reinforcement (EBR) technique, maintained in a laboratory environment (indoor and protected) or exposed to weathering (outdoor exposure). In addition, specimens of the intervenient materials were also molded and exposed to the same environmental conditions as the beams. The results indicate that weather-exposed epoxy adhesives present reductions up to 70% in their mechanical properties after exposure, while the CFRP composite properties remain similar. It was also found that the strengthening system provided 50% and 28% increments in the load-carrying capacity and stiffness of the elements, respectively. However, the tests conducted after 6 months of weathering exposure showed a 10% reduction in the load-carrying capacity of the strengthened elements.

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