• Composites Research
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• v.17 no.2
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• pp.9-14
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• 2004

In this study, analytical investigations on the flexural behavior of FRP reinforced concrete slab were discussed. In the derivation of analytic solution, the FRP reinforced concrete slab was modeled as a structural orthotropic plate. To determine the flexural rigidities of an orthotropic plate model, the elastic equivalence method was employed. In the finite element analysis, the approximate method to determine the rigidity matrix of orthotropic plate element was also suggested using the elastic equivalence method. The results obtained by the analytical solution and the finite element analysis were compared with that of experiment.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.667-675
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• 2004

This paper presents the failure mode and strengthening design of reinforced concrete slab strengthened with Carbon Fiber Reinforced Polymer(CFRP) grid. Parameters involved in this experimental study are FRP grid reinforcement quantity, repair mortar thickness, the presence of anchor, and strengthening in compression. In this study, there are different failure types with increasing the CFRP grid strengthening reinforcement. On the low strengthening level, CFRP grid in repair mortar cover ruptures. On the moderate strengthening level, there is a debonding shear failure in the interface of carbon FRP grid because of the excessive shear deformation. On the high strengthening level, diagonal shear failure occurs. With the increasing of FRP grid reinforcement, the strengthening effect increased, but the ductility decreased. By limiting the strengthening level, it can be achieved to prevent shear failure which result in sudden loss in the resisting load capacity. CFRP rupture failure is desirable, because CFRP ruptured concrete slab keeps the same load capacity and ductility haying before strengthening even after failure. Finally, design guideline and procedure are given for strengthening of concrete slab with CFRP grid.

• Journal of the Korea Concrete Institute
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• v.19 no.6
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• pp.727-734
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• 2007

The influence of the differences in the physical and mechanical properties between fiber-reinforced polymer (FRP) and conventional steel, concentrated reinforcement in the immediate column region, as well as using steel fiber-reinforced concrete (SFRC) in the slab near the column faces, on the punching behavior of two-way slabs were investigated. The punching shear capacity, stiffness, ductility, strain distribution, and crack control were investigated. Concentrating of the slab reinforcement and the use of SFRC in the slab enhanced the punching behavior of the slabs reinforced with glass fiber-reinforced polymer (GFRP) bars. In addition the test results of the slabs with concentrated reinforcement were compared with various code equations and the predictions proposed in the literature specifically for FRP-reinforced slabs. An appropriate method for determining the reinforcement ratio of slabs with a banded distribution was also investigated to allow predictions to properly reflect the benefit of the slab reinforcement concentration.

• Advances in concrete construction
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• v.16 no.4
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• pp.205-216
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• 2023

Concrete structures may become vulnerable during their lifetime due to several reasons such as degradation of their material properties; design or construction errors; and environmental damage due to earthquake. These structures should be repaired or strengthened to ensure proper performance for the current service load demands. Several methods have been investigated and applied for the strengthening of reinforced concrete (RC) structures using various materials. Fiber reinforced polymer (FRP) reinforcement is one of the most recent type of material for the strengthening purpose of RC structures. The main objective of the present research is to identify the behavior of reinforced concrete slabs strengthened with FRP bars by using near surface mounted (NSM) technique. Validation study is conducted based on the experimental test available in the literature to investigate the accuracy of finite element models using LS-DYNA to present the behavior of the models. A parametric analysis is conducted on the effect of FRP bar diameters, number of grooves, groove intervals as well as width and height of the grooves on the flexural behavior of strengthened reinforced slabs. Performance of strengthening RC slabs with NSM FRP bars was confirmed by comparing the results of strengthening reinforced slabs with control slab. The numerical results of mid-span deflection and stress time histories were reported. According to the numerical analysis results, the model with three grooves, FRP bar diameter of 10 mm and grooves distances of 100 mm is the most ideal and desirable model in this research. The results demonstrated that strengthening of reinforced concrete slabs using FRP by NSM method will have a significant effect on the performance of the slabs.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.13-17
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• 2004

In recent years, the deterioration of reinforced concrete structures has become a serious problem in civil engineering fields. This situation is mainly due to corrosion of steel reinforcing bars embedded in concrete. Recently, there has been a greatly increased demand for the use of FRP (fiber reinforced plastic) in civil engineering field due to their superior mechanical and physical properties. This paper presents an experimental study on the behavior of concrete bridge deck reinforced with FRP Box, FRP Plate, and FRP Re-bar. In tlIe study, mechanical properties of FRP Box, FRP Plate, GFRP Re-bar, and CFRP Grid have been investigated. Full scale one-way deck slab was tested under four point lateral load (equivalent to actual wheel load of DB-24 including impact). Load-deflection and load-strain data were collected through LVDT's and strain gages attached to the specimen.

• Advances in concrete construction
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• v.8 no.3
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• pp.165-172
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• 2019

Progressive collapse is one of the factors which if not predicted at the time of structure plan; its occurrence will lead to catastrophic damages. Through having a glance over important structures chronicles in the world, we will notice that the reason of their collapse is a minor damage in structure caused by an accident like a terrorist attack, smashing a vehicle, fire, gas explosion, construction flaws and its expanding. Progressive collapse includes expanding rudimentary rupture from one part to another which leads to total collapse of a structure or a major part it. This study examines the progressive collapse of a 5-story concrete building with three column eliminating scenarios, including the removal of the corner, side and middle columns with the ABAQUS software. Then the beams and the bottom of the concrete slab were reinforced by (reinforcement of carbon fiber reinforced polymer) FRP and then the structure was re-analyzed. The results of the analysis show that the reinforcement of carbon fiber reinforced polymer sheets is one of the effective ways to rehabilitate and reduce the progressive collapse in concrete structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.173-181
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• 2021

Reinforced concrete structures are exposed to various environments, resulting in reinforcement corrosion due to moisture and ions penetration. Reinforced concrete corrosion causes a decrease in the durability performance of reinforced concrete structures. One solution to mitigate such issues is using FRP rebars, which offer several advantages such as high tensile strength, corrosion resistance, and light-weight than conventional rebars, in reinforced concrete instead of conventional steel rebars. The FRP rebar used should be examined at the limit state because FRP reinforced concrete has linear behavior until its fracture and can generate excessive deflection due to the low elastic modulus. It should be considered while designing FRP reinforced concrete for flexure. In the ultimate limit state, the flexural strength of FRP reinforced concrete as per ACI 440.1R is significantly lower than the flexural strength by applying both the environmental reduction and strength reduction factors accounting for the material uncertainty of FRP rebar. Therefore, in this study, the experimental results were compared with the deflection of the proposed effective moment of inertia referring to the local and international standards. The experimental results of GFRP and BFRP reinforced concrete were compared with the flexural strength as determined by ACI 440.1R and Fib bulletin 40. The flexural strength obtained by the experimental results was more similar to that obtained by Fib bulletin 40 than ACI 440.1R. The flexural strength of ACI 440.1R was conservatively evaluated in the tension-controlled section.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.185-188
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• 2006

Recently, an improved capacity for RC bridges is required by their deterioration or necessary to carry traffic increase. Strengthening is known as a better way to improve capacity of bridges than reconstructing. Fiber Reinforced Plastics (FRP) is introduced as one of the best strengthening structures in this paper. It is also known as an economical improvement. Therefore, FRP sheet and Glass Fiber-Steel Composite Plate (GSP) in this research were used in strengthening slab of RC bridges. Experimental data from the strengthening will be helpful to better understand the slab behavior and an effect of the strengthening.

• Composites Research
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• v.16 no.3
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• pp.32-40
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• 2003

In recent years, the investigation on the development of fiber reinforced plastic(FRP) Re-Bar has been greatly increased due to the attractive physical and mechanical properties of FRP. The primary reason of such a tendency is in the fact that it does not ordinarily cause durability problems such as those associated with steel reinforcement corrosion. This study is an experimental investigation on the flexural behavior of one-way concrete slabs, which can be used to construct bridge deck, reinforced with GFRP Re-Bar bundle. The tensile tests of GFRP Re-Bar produced by domestic industry and third point bending tests of one-way slab specimens reinforced with GFRP Re-Bar bundle are peformed. For all slab specimens, load-deflection relations are predicted by using the ACI committee 440 and the results are compared with experimental ones. In order to establish the design criteria or guidelines of concrete flexural member reinforced with FRP Re-Bar, it is needed to evaluate the serviceability limit state as well as the strength limit state.

• Steel and Composite Structures
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• v.43 no.2
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• pp.229-240
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• 2022

The main objective of this work is presenting a mathematical model for the concrete slab with fiber reinforced polymer (FRP) layer under the impact load. Impacts are assumed to occur normally over the top slab and the interaction between the impactor and the structure is simulated using a new equivalent three-degree-of-freedom (TDOF) spring-mass-damper (SMD) model. The structure is assumed viscoelastic based on Kelvin-Voigt model. Based on the sinusoidal shear deformation theory (SSDT), energy method and Hamilton's principle, the motion equations are derived. Applying DQM, the dynamic deflection and contact force of the structure is calculated numerically so that the effects of mass, velocity and height of impactor, boundary conditions, FRP layer, structural damping and geometrical parameters of structure are shown on the dynamic deflection and contact force of system. Results show that considering structural damping leads to lower dynamic deflection and contact force. In addition, increasing the impact velocity of impactor yields to increases in the maximum contact force and deflection while the contact duration is decreased. The result shows that the contact force and the central deflection of the structure decreases and the contact time decreases with assuming FRP layer.