Structural performance and serviceability of concrete beams reinforced with hybrid (GFRP and steel) bars

Refai, Ahmed El; Abed, Farid; Al-Rahmani, Abdullah

doi:10.1016/j.conbuildmat.2015.08.063

Cited by 164 publications

(71 citation statements)

References 8 publications

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“…These attempts were not practical to be implemented in the construction industry due to the high cost and complexity of manufacturing process. More practical solutions have been suggested such as; confinement of concrete in compression zone [14], addition of fibres to concrete [15][16][17] and use of a hybrid combination of FRP and steel re-bars [18][19][20][21][22][23][24][25][26]. Such hybrid reinforcement system shows improved serviceability and ductility, and enhancement of load-carrying capacity compared to traditional reinforcement [19,21].…”

Section: Introductionmentioning

confidence: 99%

Flexural performance of hybrid GFRP-Steel reinforced concrete continuous beams

Araba

Ashour

2018

Composites Part B: Engineering

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This paper presents the experimental results of five large-scale hybrid glass fiber reinforced polymer (GFRP)-steel reinforced concrete continuous beams compared with two concrete continuous beams reinforced with either steel or GFRP bars as reference beams. In addition, two simply supported concrete beams reinforced with hybrid GFRP/steel were tested. The amount of longitudinal GFRP, steel reinforcements and area of steel bars to GFRP bars were the main investigated parameter in this study. The experimental results showed that increasing the GFRP reinforcement ratio simultaneously at the sagging and hogging zones resulted in an increase in the load capacity, however, less ductile behaviour. On the other hand, increasing the steel reinforcement ratio at critical sections resulted in more ductile behaviour, however, less load capacity increase after yielding of steel.The test results were compared with code equations and available theoretical models for predicting the beam load capacity and load-deflection response. It was concluded that Yoon's model reasonably predicted the deflection of the hybrid beams tested, whereas, the ACI.440.1R-15 equation underestimated the hybrid beam deflections. It was also shown that the load capacity prediction for hybrid reinforced concrete continuous beams based on a collapse mechanism with plastic hinges at mid-span and central support sections was reasonably close to the experimental failure load.

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Section: Introductionmentioning

confidence: 99%

Flexural performance of hybrid GFRP-Steel reinforced concrete continuous beams

Araba

Ashour

2018

Composites Part B: Engineering

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“…While structures made of conventional materials may exhibit some postyield stiffness (usually less than 10% of the initial stiffness), the application of new materials with high strength and superior elastic properties can easily be used to develop structures with a much higher and more stable postyield stiffness. These high‐strength elastic materials, such as fiber‐reinforced polymer (FRP) and high‐strength steel bars, exhibit little or approximately no plastic behavior and have been recently used to fabricate many novel materials, members, and structures. Compared with the components made of only conventional materials (steel and concrete), increasingly more materials, members, and structures that incorporate both high‐strength elastic materials and conventional materials show significant postyield hardening (PYH) skeleton curves (Figure ).…”

Section: Introductionmentioning

confidence: 99%

“…Compared with the components made of only conventional materials (steel and concrete), increasingly more materials, members, and structures that incorporate both high‐strength elastic materials and conventional materials show significant postyield hardening (PYH) skeleton curves (Figure ). A variety of such innovative components are summarized in Table (references cited in Table ). These materials, members, and structures can be called PYH materials, members, and structures, respectively.…”

Section: Introductionmentioning

confidence: 99%

Seismic responses of postyield hardening single–degree‐of‐freedom systems incorporating high‐strength elastic material

Qiang

Feng

Qu³

2019

Earthq Engng Struct Dyn

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It is widely accepted that ductility design improves the seismic capacity of structures worldwide. Nevertheless, inelastic deformation allows serious damage to occur in structures. Previous studies have shown that a certain level of postyield stiffness may reduce both the peak displacement and residual deformation of a structure. In recent years, several high-strength elastic materials, such as fiber-reinforced polymer (FRP) and high-strength steel bars, have been developed. Application of these materials can easily provide a structure with a much higher and more stable postyield stiffness. Many materials, members, and structures that incorporate both high-strength elastic materials and conventional materials show significant postyield hardening (PYH) behaviors.The significant postyield stiffness of PYH structures can help effectively reduce both peak and residual deformations, providing a choice when designing resilient structures. However, the findings of previous studies of structures with elastic-perfectly plastic (EPP) behavior or small postyield stiffness may not be accurate for PYH structures. The postyield stiffness of a structure must be considered an important primary structural parameter, in addition to initial stiffness, yielding strength, and ductility. In this paper, extensive time history and statistical analyses are carried out for PYH single-degree-of-freedom (SDOF) systems. The mean values and coefficients of variation of the peak displacement and residual deformation are obtained and discussed. A new R-μ p -T-α relationship and damage index for PYH structures are proposed. A theoretical model for the calculation of residual deformation is also established. These models provide a basis for developing the appropriate seismic design and performance evaluation procedures for PYH structures.KEYWORDS damage index, high-strength elastic materials, peak displacement, postyield stiffness, residual deformation, single degree of freedom

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“…A ductility index was proposed by Pang et al (2015) [13] to evaluate the load-displacement relationship of a hybrid reinforced concrete beam and the corresponding method of differentiation of the failure mode was suggested, but this method of differentiation was slightly complicated. An experimental study on six hybrid reinforced concrete beams was conducted by El Refai et al (2015) [14], and the results indicated that the deflection of the hybrid reinforcement beam with the higher reinforcement ratio can be well predicted by current design codes; the crack width was calculated by ACI-440.1R-06 [11] by modifying the bonding coefficient between the FRP bar and concrete.…”

Section: Introductionmentioning

confidence: 99%

Moment-Curvature Behaviors of Concrete Beams Singly Reinforced by Steel-FRP Composite Bars

Sun

Yang

Yan

et al. 2017

Advances in Civil Engineering

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A steel-fiber-reinforced polymer (FRP) composite bar (SFCB) is a kind of rebar with inner steel bar wrapped by FRP, which can achieve a better anticorrosion performance than that of ordinary steel bar. The high ultimate strength of FRP can also provide a significant increase in load bearing capacity. Based on the adequate simulation of the load-displacement behaviors of concrete beams reinforced by SFCBs, a parametric analysis of the moment-curvature behaviors of concrete beams that are singly reinforced by SFCB was conducted. The critical reinforcement ratio for differentiating the beam's failure mode was presented, and the concept of the maximum possible peak curvature (MPPC) was proposed. After the ultimate curvature reached MPPC, it decreased with an increase in the postyield stiffness ratio ( sf ), and the theoretical calculation method about the curvatures before and after the MPPC was derived. The influence of the reinforcement ratio, effective depth, and FRP ultimate strain on the ultimate point was studied by the dimensionless moment and curvature. By calculating the envelope area under the moment-curvature curve, the energy ductility index can obtain a balance between the bearing capacity and the deformation ability. This paper can provide a reference for the design of concrete beams that are reinforced by SFCB or hybrid steel bar/FRP bar.

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Structural performance and serviceability of concrete beams reinforced with hybrid (GFRP and steel) bars

Cited by 164 publications

References 8 publications

Flexural performance of hybrid GFRP-Steel reinforced concrete continuous beams

Flexural performance of hybrid GFRP-Steel reinforced concrete continuous beams

Seismic responses of postyield hardening single–degree‐of‐freedom systems incorporating high‐strength elastic material

Moment-Curvature Behaviors of Concrete Beams Singly Reinforced by Steel-FRP Composite Bars

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