Simple equations for predicting the rotational ductility of fiber-reinforced-polymer strengthened reinforced concrete joints

Tahnat, Yazan B. Abu; Samaaneh, Mohammad A.; Dwaikat, Mahmud; Halahla, Abdulsamee M.

doi:10.1016/j.istruc.2020.01.010

Cited by 15 publications

(7 citation statements)

References 21 publications

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“…In Figure 23, prior to cracking, the displacement of various test pieces develops slowly; the relationship between displacement and load is approximately linear; this indicates that the test pieces are at elastic working state; after cracking and before yielding, the slopes of curves of various test pieces reduce gradually; this is because the cracking with the chord weakens the overall lateral stiffness of the test pieces and makes the curve gradually slow down; after the test pieces yield, the displacement increases quickly with the application of the load; the curves of the test pieces have smooth sections; this indicates that the test pieces have better deformation capacity; after the ultimate load is reached, the increase of loading becomes impossible; the displacement further increases and indicates that the test pieces failed. In fact, curve variation rule of Figure 23 is similar to that of other types of reinforced concrete members [26][27][28]. At failure, the average strain values of the measuring points 4, 8, and 12 of group 1 and group 2 are greater than the yield strain values, while the average strain values of 3-A and 3-B are less than the yield strain values.…”

Section: Load-displacement Curvesupporting

confidence: 64%

Experimental Study and Numerical Study on Shear Bearing Capacity of Shear Key Joints of Reinforced Concrete Open‐Web Sandwich Plates

Zhang

et al. 2021

Advances in Materials Science and Engineering

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The shear key in the reinforced concrete open-web sandwich plate (RCOSP) is a block joint that connects with the top chord and the bottom chord. In order to understand the failure mode of the shear key and verify the accuracy of the current algorithm, a total of 9 test pieces are prepared and classified 3 groups were assigned longitudinal reinforcement (LR) ratios of 0.49%, 0.82%, and 1.24%, respectively. The horizontal concentrated static loading under simple support condition is carried out. The test results show that the shear key is horizontally cut and the concrete is pulled apart or crushed along the direction of chord width at the shear key-chords area; the strain level of the concrete and stirrup of the shear key is lower averagely; the development of the horizontal displacement and the strain of the longitudinal bars of the test pieces goes through elastic, elastoplastic, and plastic stages; the ultimate load of the test pieces has almost no relationship with the reinforcement ratio of shear key but is controlled by the degree of crack development in the area where shear key connects with the chords. To avoid the current algorithm overestimating the shear capacity of shear key, the restricted condition of shear section is proposed. The finite element analysis (FEA) further verifies that the restricted condition of shear section proposed in this paper is reasonable and necessary.

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Section: Load-displacement Curvesupporting

confidence: 64%

Experimental Study and Numerical Study on Shear Bearing Capacity of Shear Key Joints of Reinforced Concrete Open‐Web Sandwich Plates

Zhang

et al. 2021

Advances in Materials Science and Engineering

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“…The ABAQUS user manual describes the expansion angle ψ, eccentricity e, ultimate strength ratio of biaxial bearing to uniaxial bearing f b0 /f c0 , ratio of second stress invariants K and viscosity coefficient m. The physical meaning of the parameters and the reference values were provided. Many researchers (Jiang et al, 2005;Tahnat et al, 2020) have used these parameters, and the results obtained are in good agreement with the experimental tests. The parameters of the plastic damage model are shown in Table 4 below.…”

Section: Characteristics Of Concretesupporting

confidence: 64%

“…The physical meaning of the parameters and the reference values were provided. Many researchers (Jiang et al ., 2005; Tahnat et al ., 2020) have used these parameters, and the results obtained are in good agreement with the experimental tests. The parameters of the plastic damage model are shown in Table 4 below.…”

Section: The Establishment Of a Finite Element Modelmentioning

confidence: 99%

Study on the calculation method of the maximum number of bonded steel plates at the bottom of reinforced concrete beams

Wang,

Yu,

Xiao

et al. 2024

IJSI

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Purpose When the reinforced concrete beams are reinforced by bonding steel plates to the bottom, excessive use of steel plates will make the reinforced concrete beams become super-reinforced beams, and there are security risks in the actual use of super-reinforced beams. In order to avoid the occurrence of this situation, the purpose of this paper is to study the calculation method of the maximum number of bonded steel plates to reinforce reinforced concrete beams.Design/methodology/approach First of all, when establishing the limit failure state of the reinforced member, this paper comprehensively considers the role of the tensile steel bar and steel plate and takes the load effect before reinforcement as the negative contribution of the maximum number of bonded steel plates that can be used for reinforcement. Through the definition of the equivalent tensile strength, equivalent elastic modulus and equivalent yield strain of the tensile steel bar and steel plate, a method to determine the relative limit compression zone height of the reinforced member is obtained. Second, based on the maximum ratio of (reinforcement + steel plate), the relative limit compression zone height and the equivalent tensile strength of the tensile steel bar and steel plate of the reinforced member, the calculation method of the maximum number of bonded steel plates is derived. Then, the static load test of the test beam is carried out and the corresponding numerical model is established, and the reliability of the numerical model is verified by comparison. Finally, the accuracy of the calculation method of the maximum number of bonded steel plates is proved by the numerical model.Findings The numerical simulation results show that when the steel plate width is 800 mm and the thickness is 1–4 mm, the reinforced concrete beam has a delayed yield platform when it reaches the limit state, and the failure mode conforms to the basic stress characteristics of the balanced-reinforced beam. When the steel plate thickness is 5–8 mm, the sudden failure occurs without obvious warning when the reinforced concrete beam reaches the limit state. The failure mode conforms to the basic mechanical characteristics of the super-reinforced beam failure, and the bending moment of the beam failure depends only on the compressive strength of the concrete. The results of the calculation and analysis show that the maximum number of bonded steel plates for reinforced concrete beams in this experiment is 3,487 mm2. When the width of the steel plate is 800 mm, the maximum thickness of the steel plate can be 4.36 mm. That is, when the thickness of the steel plate, the reinforced concrete beam is still the balanced-reinforced beam. When the thickness of the steel plate, the reinforced concrete beam will become a super-reinforced beam after reinforcement. The calculation results are in good agreement with the numerical simulation results, which proves the accuracy of the calculation method.Originality/value This paper presents a method for calculating the maximum number of steel plates attached to the bottom of reinforced concrete beams. First, based on the experimental research, the failure mode of reinforced concrete beams with different number of steel plates is simulated by the numerical model, and then the result of the calculation method is compared with the result of the numerical simulation to ensure the accuracy of the calculation method of the maximum number of bonded steel plates. And the study does not require a large number of experimental samples, which has a certain economy. The research result can be used to control the number of steel plates in similar reinforcement designs.

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“…When using concrete plastic damage model, a set of parameters need to be determined in the modeling process to capture the mechanical behavior of concrete accurately. The default values of these parameters are taken from Halahla et al (2019) and Tahnat et al (2020), and the simulated results obtained by using these parameters were in good agreement with the experimental results. These parameters were also used in this paper, as shown in Table 3.…”

Section: Experiments Overviewsupporting

confidence: 60%

“…The default values of these parameters are taken from Halahla et al. (2019) and Tahnat et al. (2020), and the simulated results obtained by using these parameters were in good agreement with the experimental results.…”

Section: Finite Element Modelsupporting

confidence: 60%

An innovative reinforcement method: the combination of CFRP bars and UHPC layer is applied to the flexural reinforcement of RC beams

Liu

et al. 2022

MMMS

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PurposeEmbedding carbon fiber reinforced plastics (CFRP) bars in the tension zone of reinforced concrete (RC) beams is a widely used reinforcement method, which has the advantages of strong anti-peel ability and high utilization of tensile materials. To further improve the flexural bearing capacity of RC beams, a new composite reinforcement method using the UHPC layer in the compressive zone of RC beams is proposed based on embedding CFRP bars in the tension zone of RC beams.Design/methodology/approachThe finite element model of an RC experimental beam with CFRP bars embedded in the tension zone was carried out by ABAQUS. Besides, the reliability of the finite element model results was verified by comparing with the experimental results. On this basis, the flexural reinforcement effect of CFRP bars and UHPC layers on RC beams was analyzed.FindingsCalculation results show the flexural bearing capacity of the beam strengthened by the new method is 15.9%, which is higher than that of the unreinforced beam, and 10.4% higher than that of the beam strengthened only with CFRP bars. The beam ductility ratio of the new method is 8.25%, which is slightly higher than that of the unreinforced beam and equal to that of the beam reinforced only with CFRP bars embedded in the tension zone. The effectiveness of the new method is further verified by using the analytical calculation method.Originality/valueA new flexural reinforcement method for reinforced concrete beams is proposed, and the effectiveness of the method was verified by experiments and finite element model. The flexural bearing capacity and ductility of the new method were analyzed based on the load-deflection curve. Finally, the possibility of the new method was verified by analytical analysis.

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Simple equations for predicting the rotational ductility of fiber-reinforced-polymer strengthened reinforced concrete joints

Cited by 15 publications

References 21 publications

Experimental Study and Numerical Study on Shear Bearing Capacity of Shear Key Joints of Reinforced Concrete Open‐Web Sandwich Plates

Experimental Study and Numerical Study on Shear Bearing Capacity of Shear Key Joints of Reinforced Concrete Open‐Web Sandwich Plates

Study on the calculation method of the maximum number of bonded steel plates at the bottom of reinforced concrete beams

An innovative reinforcement method: the combination of CFRP bars and UHPC layer is applied to the flexural reinforcement of RC beams

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