Design Propositions for Hybrid FRP-Steel Reinforced Concrete Beams

Pang, Lei; Qu, Wenjun; Zhu, Pinghua; Xu, Jiaqin

doi:10.1061/(asce)cc.1943-5614.0000654

Cited by 76 publications

(48 citation statements)

References 6 publications

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“…Similar to the researches mentioned above, the failure mode of almost hybrid concrete beams is first yielding in steel bars then crushing in concrete of compression zone. This is a typical failure mechanism found in previous many studies [1,5,6]. In fact, there may still be several modes of failure in hybrid GFRP/steel concrete beams that have not been reported and this study fills the gap by focusing on those failure modes.…”

Section: Introductionmentioning

confidence: 75%

Performance of Concrete Beams Reinforced with Various Ratios of Hybrid GFRP/Steel Bars

Nguyen

Dang

2020

Civ Eng J

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This paper aims to study the flexural behavior of concrete beams reinforced with hybrid combinations of GFRP/steel bars. To this purpose an experimental program was carried out on four concrete beams reinforced with Glass Fiber Reinforced Polymer (GFRP) and twelve hybrid GFRP/steel Reinforced Concrete (RC) beams. Flexural behavior of the tested beams such as stages of response, failure modes, crack patterns, stiffness, toughness and ductility were analyzed. The experimental results showed that depending on GFRP/steel reinforcement configurations, the behavior of hybrid GFRP/steel RC beams undergoes three or four stages, namely: pre-cracking stage; after concrete cracking and before steel yielding; post-yield stage of the steel bar until peak load and failure stage. Totally six failure modes of hybrid RC beams are reported depending on reinforcement rations and configuration. The effect of reinforcement configuration and ratio of GFRP to steel (ρg) on the crack patterns, stiffness, ductility and toughness of hybrid RC beams are significant. Based on the non-linear deformation model, an analytical model has been developed and validated to determine the steel yielding moment and ultimate moment of hybrid GFRP/steel RC beams. It could be seen that the experimental values were in good agreement with the predicted values.

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Section: Introductionmentioning

confidence: 75%

Performance of Concrete Beams Reinforced with Various Ratios of Hybrid GFRP/Steel Bars

Nguyen

Dang

2020

Civ Eng J

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“…The effective reinforcement stiffness ρ sf,s and the mechanical reinforcing index ρ sf,f are calculated by Eqs. (3) and (4) (Pang et al 2015 [13]):…”

Section: Existing Models For Effective Moment Of Inertia Calculationmentioning

confidence: 99%

“…The yield reinforcement ratio ρ sb can be calculated as the reinforcement ratio when concrete crushing and steel yielding occur simultaneously but the FRP bars have not yet ruptured. The ρ fb can be calculated as the reinforcement ratio when concrete crushing and FRP bar rupturing occur simultaneously after the steel rebars have yielded (Pang et al 2015 [13]). ρ sb calculated by Eq.…”

Section: Existing Models For Effective Moment Of Inertia Calculationmentioning

confidence: 99%

“…Results show that when the mechanical reinforcing index, ρ sf,f , is greater than the critical reinforcement ratio, ρ fb , and the effective reinforcement stiffness, ρ sf,s , is less than the yield reinforcement ratio, ρ sb , flexural failure of the beam will begin with steel yielding followed by concrete crushing and eventually FRP bar rupturing. The section is underreinforced, which is a preferred approach in the design of hybrid-RC members (Pang et al 2015 [13]). Underreinforced beam design can be adopted as an economical method in hybrid RC design.…”

Section: Existing Models For Effective Moment Of Inertia Calculationmentioning

confidence: 99%

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Prediction of effective moment of inertia for hybrid FRP-steel reinforced concrete beams using the genetic algorithm

Kheyroddin

Maleki

2017

NMCE

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The use of Concrete beams reinforced with a combination of fiber reinforced polymer (FRP) and steel bars has increased dramatically in recent years, due to improvement in strength and flexural ductility simultaneously. In this paper, we proposed a new equation for estimating the effective moment of inertia of hybrid FRP-steel reinforced concrete (RC) beams on the basis of the genetic algorithm and experimental results.The genetic algorithm is used to optimize the percent error between experimental and analytical responses. In the proposed equation, additional coefficients are considered in order to take into account the specific properties of FRP bars. The effects of the elastic modulus of FRP and steel bars, the hybrid reinforcement ratio, A f /A s , and the different level of loading on the effective moment of inertia has been considered.These coefficients are used to modify Branson's equation to compute the effective moment of inertia of concrete beams reinforced by FRP and steel bars. Comparison between the experimental and predicted results showed the adequacy of the model used in predicting the effective moment of inertia, and deflection of hybrid-RC beams.

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“…A study of twelve concrete beams, which were reinforced by steel bar and GFRP bar, was conducted by Safan (2013) [12], and the results showed that the failure modes of concrete beams were presented as concrete crushing after the yielding of the steel bar on the tensile side and a GFRP bar can maintain the flexural bearing capacity of a concrete beam with a relatively small reinforcement ratio. 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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Design Propositions for Hybrid FRP-Steel Reinforced Concrete Beams

Cited by 76 publications

References 6 publications

Performance of Concrete Beams Reinforced with Various Ratios of Hybrid GFRP/Steel Bars

Performance of Concrete Beams Reinforced with Various Ratios of Hybrid GFRP/Steel Bars

Prediction of effective moment of inertia for hybrid FRP-steel reinforced concrete beams using the genetic algorithm

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

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