Evaluate of Flexural Behavior of the Prestressed Concrete Girder Using Carbon Fiber Reinforced Plastics via Finite Element Method (original) (raw)
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2021
DOI: http://dx.doi.org/10.24018/ejers.2021.6.1.2323 Vol 6 | Issue 1 | January 2021 55 fc = fc ’ [2(Єc /Є∘) − (Єc /Є∘) ] (1) Abstract — The effect of Carbon Fiber Reinforced Polymer (CFRP) retrofitting and concrete type on the flexural strength of prestressed concrete I-section girders used in bridges and beams in buildings is investigated. Non-linear momentcurvature relationships are predicted using an iterative algorithm for both non-retrofitted and CFRP-retrofitted prestressed concrete girder and beam cross-sections with various concrete types. Two different CFRP-retrofitting schemes are analyzed for comparing their effectiveness. It is found that although non-retrofitted beam section exhibits greater ductility, the use of CFRP retrofitting in both tension and compression regions simultaneously results in a significant increase in flexural strength. It is also found that the higher the ultimate concrete strength, the higher is the influence of CFRPretrofitting on increasing flexur...
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Precast segmental prestressed concrete beams (PSBs) have been widely used in many elevated highway bridge projects around the world. Steel tendons at joint locations, however, are vulnerable to corrosion damages, which cause deteriorations and in extreme cases lead to the collapse of the whole structures. This study experimentally investigates the use of carbon fibre-reinforced polymer (CFRP) tendons as an alternative solution for the PSBs to tackle the corrosion issue. Four large-scale segmental T-shaped concrete beams with internal bonded or unbonded tendons and dry or epoxied joints were built and tested under four-point loading. The test results indicated that CFRP tendons showed satisfactory performances therefore could replace steel tendons for the use in PSBs. All the tested beams exhibited excellent loadcarrying capacity and ductility. Tendon bonding condition greatly affected the flexural performance of the segmental beams. Joint type had only a slight effect on the load-carrying capacity and ductility of the beams, but significantly affected the beams' initial stiffness. Unbonded tendons experienced an evident reduction in the tendon strength at the ultimate stage as a consequence of the loading type, harping effect and joint opening. Both AASTHO
Investigating Flexural Behaviour of Prestressed Concrete Girders Cast by Fibre-Reinforced Concrete
Advances in Civil Engineering, 2019
The main objective of this research was to investigate the effect of adding polypropylene and steel fibres on flexural behaviour of prestressed concrete girders. Although the construction industry is frequently using prestressed concrete to increase the load-carrying capacity of structures, it can be further enhanced by using fibres. In this paper, experimental work was carried out to encourage the construction industry in utilizing fibres in prestressed concrete members to improve the mechanical properties of these members. As past investigations on fibre-reinforced prestressed beams were limited, the present work was done on small-scale fibre-reinforced I-shaped prestressed concrete girders. Six small-scale prestressed concrete girders were cast comprising a control girder, a hybrid girder, two girders with varying percentages of steel fibres, and two girders with varying percentages of polypropylene fibres. These girders were tested by centre point loading up to failure. It was c...
Behaviour of BH Girder Composed of CIP and Precast concrete Subjected to Flexural Loading
IOP Conference Series: Materials Science and Engineering, 2018
This paper presents the behaviour of reinforced BH girder which is made of precast, and cast in place (CIP) subjected to flexural loading (bending). The girder is made of two types of concrete materials, precast and cast in place (CIP), which has different strengths. The girder is simply supported and loading force is given at the mid span of the beam during analysis. The main objective of the analysis and modelling is to studying the combined effect of CIP, precast and the reinforcing materials. Modelling process is carried out using Rigid-Body-Spring-Network (RBSN) and Abaqus commercial software. Cracking and failure behaviour of the girder is investigated. Performance of the BH girder (precast and CIP) is estimated based on the load carrying capacity. Deflection of the composite is measured along the span of the girder. From the analysis result; the ductility, load carrying capacity and crack initiation and crack propagation behaviour of BH girder is investigated.
Numerical Simulation of Prestressed CFRP Plate Strengthened Steel-Concrete Composite Girders
Advances in FRP Composites in Civil Engineering, 2011
This paper presents the results of Finite Element (FE) modeling of flexural behavior of steelconcrete composite girders strengthened with prestressed Carbon Fiber Reinforced Polymer (CFRP) plate. To the best knowledge of the authors, this is the first numerical modeling of such application with prestress available in the literature The level of prestressing that is used to validate the model is 12% of the ultimate tensile strength of the CFRP plate and it is based on the results of an experimental study conducted at University of Calgary on the same large-scale beam tested in bending under monotonic static loading. Comparison shows a very good agreement between the numerical and the experimental results. After validation of the model, a parametric study using different prestressing levels is conducted and the effects of increasing the prestress level on ductility index, yield and ultimate loads are presented.
Flexural Response of CFRP-Prestressed Concrete Beams
2020
DOI:10.17605/OSF.IO/WCDZP Page 1 AbstractThis paper presents a numerical analysis investigation of the behavior of prstressed beams with carbon fiber strands (CFRP). Three dimensional finite element beam models are created on the finite element software ANSYS2013 to study the flexural response of the investigated models. The investigated models have two different types of prestressing cables, namely; steel and CFRP tendons. A parametric study was conducted to examine the effects of prestressing reinforcement ratio, concrete strength, and level of initial prestressing on the behavior of the studied prestressed concrete models. The results show that the CFRP cables can be as effective as steel cables.
Engineering Structures, 2018
This study investigates the use of carbon fibre reinforced polymer (CFRP) tendons on precast segmental beams (PSBs) to tackle the corrosion problems which are likely to occur at joint locations of PSBs prestressed with steel tendons. Up to date, the use of CFRP tendons was extensively documented for monolithic beams while their application on PSBs has not been reported yet. Three precast segmental T-section beams including two beams with unbonded CFRP and one with steel tendons were built and tested under four-point loads in this study. The test results showed that CFRP tendons can be well used to replace the steel tendons on PSBs. The beams with CFRP tendons demonstrated both high strength and high ductility as compared to the beam with steel tendons. However, the stresses in the unbonded CFRP tendons at ultimate loading conditions of the tested beams were low, ranging from only about 66% to 72% of the nominal breaking tensile strength. The type of joints i.e. dry and epoxied, greatly affects the initial stiffness of the beams but has no effect on the opening of joints at ultimate loading stage. Moreover, a comprehensive examination on four existing code equations to predict the stress in the unbonded tendons showed that the four examined codes predicted well
Strength Evaluation of Steel-Concrete Composite Girders Strengthened with Prestressed FRP Laminates
This paper reports on the results obtained from strength evaluation using the diagnostic cyclic load testing of steel-concrete composite girders strengthened in flexure using prestressed FRP laminates. The strengthening materials included: Steel Reinforced Polymer (SRP) sheets and Intermediate Modulus Carbon Fiber Reinforced Polymer (IM CFRP) plate. An innovative anchorage system was developed to prestress the FRP against the girder itself. All girders were strengthened using almost the same axial stiffness (EA) of the FRP material. The FRP was prestressed with three different levels including 16 %, 28 % and 42 % of the ultimate tensile strength of the SRP sheets and 11 %, 15 % and 21 % of the ultimate tensile strength of the IM CFRP plate. The diagnostic load testing protocol was used to evaluate the flexural performance of the strengthened girders after being loaded to the service condition and past the yield load as well as to demonstrate that the prestressed FRP strengthening system is performing as required. The strengthened girders were loaded in three pairs of cyclic quasi-static concentrated load sets, and then loaded to reach the ultimate load carrying capacity. The girders' deformations were continuously monitored during the six loading-unloading cycles and until failure. Three sets of acceptance criteria were evaluated to verify whether the tested girders have passed or not the proof load test. The three parameters that have been established to analyze the behaviour of the tested girders are all related to the response of the girders in terms of displacement and these are: repeatability (consistency of response), permanency (resistance to softening), and deviation from linearity (increasing rate of deformation with increasing load). The repeatability and permanency indices for all girders were within the maximum and minimum limits indicating the confidence in the instrumentation used to measure the deflection, and indicating least permanent deformation after each cycle was recorded. The deviation from linearity for all beams exceeded the maximum limit indicating that the beams experienced plastic deformation after unloading. It was observed in the IM CFRP prestressed beams, the higher the prestressing level, the lower the deviation from linearity as the girders become more rigid. For the SRP prestressed girders, the increase in the prestressing level decreased the deviation from linearity until a certain limit-at high prestressing force-the index started to increase.
Design Approach for Carbon Fiber-Reinforced Polymer Prestressed Concrete Bridge Beams
ACI Structural Journal, 2003
This paper presents a design approach for carbon fiber-reinforced polymer (CFRP) concrete bridge beams prestressed using bonded pretensioning and unbonded post-tensioning tendons arranged in multiple vertically distributed layers along with non-prestressing CFRP rods. Design equations to determine the flexural capacity and to compute the stresses and strains in concrete and tendons are provided. In addition, based on parabolic stress-strain relation for concrete and linear stress-strain relation for tendons, a computer program was developed to compute the overall response of the beam such as deflections, strains, cracking loads, and post-tensioning forces. The design equations and the accuracy of the nonlinear computer program were validated by comparing the analytical results with experimental results from a full-scale double-T (DT) test beam. The difference in the analytical and experimental values of the ultimate moment capacity of the DT-test beam is negligible, whereas the corresponding difference in the ultimate forces in unbonded externally draped post-tensioning strands is approximately 4.1%. A detailed parametric study was conducted to examine the effect of the reinforcement ratio and the level of prestressing forces on the deflections and ultimate load-carrying capacity of the full-scale DT-beam. It is observed that the reinforcement ratio and the level of prestressing have significant effect on the moment-carrying capacity and ultimate load deflection of the beam. The combination of bonded and unbonded prestressing levels (0.3 to 0.6) can significantly increase the ultimate moment capacity of an over-reinforced beam.
Construction and Building Materials, 2015
This paper presents a three-dimensional nonlinear finite element (FE) model for prestressed concrete girders strengthened in shear with externally bonded carbon fibre reinforced polymer (CFRP) reinforcement. A total strain rotating crack model, where the crack direction changes with the change in the direction of the principal tensile stress, was used for the concrete. In this model, explicit modelling of the concrete shear behaviour after cracking, e.g. via a shear retention parameter, is not required as the crack plane is always a principal plane with no shear stresses. The FE model was validated using experimental results from the literature. An extensive parametric study was carried out to identify the effect of the concrete compressive strength, CFRP width-to-spacing ratio, CFRP thickness, girder effective depth, shear span to effective depth ratio, level of prestress, tendon profile, precracking and CFRP-to-concrete interface model on the predicted shear force capacity. The results suggested that the predicted shear strength enhancement can be significant and increases with the increase in concrete compressive strength, CFRP width-to-spacing ratio, and CFRP thickness but decreases with the increase in girder effective depth and shear span to effective depth ratio.