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1
Tao, Yi. "Fibre reinforced polymer (FRP) strengthened masonry arch structures." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7743.
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Masonry arch bridges have played a significant role in the road and rail transportation network in the world for centuries. They are exposed to damage due to overloading and deterioration caused by environmental actions. In order to reestablish their performance and to prevent their collapse in various hazardous conditions, many of them require strengthening. Fibre reinforced polymer (FRP) systems are increasingly used for repair and strengthening of structures, with particularly widespread application to concrete structures. However, the application of FRP composites to masonry structures is less well established due to the complexity of masonry caused by the material discontinuity. FRP strengthening masonry arch bridges has been even less studied due to the additional complexity arising from the co-existence of the normal interfacial stress and the shear interfacial stress at the curved FRP-to-masonry bondline. This thesis presents an extensive study investigating the behaviour of FRP strengthened masonry bridges. The study started with a laboratory test of a two span masonry arch bridge with sand backfill. A single ring arch bridge was first tested to near failure, and then repaired by bonding FRP into their intrados and tested to failure. It was found that the FRP strengthening not only improved the loading capacity and stiffness of bridge, but also significantly restrained the opening of cracks in the masonry. Shear and peeling debonding of FRP was observed. There have been two common strategies in finite element (FE) modelling of FRP strengthened structures in meso-scale: direct model and interface model. The former is necessary when investigating the detailed bond behaviour but challenges remain due to the difficulties in concrete modelling. A new concrete damage model based on the plastic degradation theory has been developed in this study to study the bond behaviour of FRP strengthened concrete structure. This robust model can successfully capture this bond behaviour and simulate the entire debonding process. A numerical study of masonry arch bridges including the backfill was conducted to study the behaviour of masonry arch bridge. A total of four modelling strategies were examined and compared. Although they all can successfully predict the behaviour of arch, a detailed solid model newly developed in this study is more suitable for modelling both plain masonry and FRP strengthened structures. Finally, a numerical study of bond behaviour and structural response of FRP strengthened masonry arch structures with sand backfill was conducted. In addition to the masonry and backfill, the mixed mode interfacial behaviour was modelled by the aforementioned interface model strategy and investigated in detail to achieve a deeper understanding of the behaviour of FRP strengthened masonry arch structures. The results are in close agreement with test results, and highlight the influence of the key parameters in the structural response to failure and revealed the mechanisms on how the load is transmitted through this complex multi-component structural system.
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Hall, Tara Stephanie. "Deflections of concrete members reinforced with fibre reinforced polymer, FRP, bars." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/MQ49676.pdf.
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Ahmed, Ehab Abdul-Mageed. "Shear behaviour of concrete beams reinforced with fibre-reinforced polymer (FRP) stirrups." Thèse, Université de Sherbrooke, 2009. http://savoirs.usherbrooke.ca/handle/11143/1903.
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Corrosion of steel reinforcement is a major cause of deterioration in reinforced concrete structures especially those exposed to harsh environmental conditions such as bridges, concrete pavements, and parking garages. The climatic conditions may have a hand in accelerating the corrosion process when large amounts of salts are used for ice removal during winter season. These conditions normally accelerate the need of costly repairs and may lead, ultimately, to catastrophic failure. Therefore, using the non-corrodible fibre-reinforced polymer (FRP) materials as an alternative reinforcement in prestressed and reinforced concrete structures is becoming a more accepted practice in structural members subjected to severe environmental exposure. This, in turn, eliminates the potential of corrosion and the associated deterioration. Stirrups for shear reinforcement normally enclose the longitudinal reinforcement and are thus the closest reinforcement to the outer concrete surface. Consequently, they are more susceptible to severe environmental conditions and may be subjected to related deterioration, which reduces the service life of the structure. Thus, replacing the conventional stirrups with the non-corrodible FRP ones is a promising aspect to provide more protection for structural members subjected to severe environmental exposure. However, from the design point of view, the direct replacement of steel with FRP bars is not possible due to various differences in the mechanical and physical properties of the FRP materials compared to steel. These differences include higher tensile strength, lower modulus of elasticity, different bond characteristics, and absence of a yielding plateau in the stress-strain relationships of FRP materials. Moreover, the use of FRP as shear reinforcement (stirrups) for concrete members has not been sufficiently explored to provide a rational model and satisfactory guidelines to predict the shear strength of concrete members reinforced with such type of stirrups. An experimental program to investigate the structural performance of FRP stirrups as shear reinforcement for concrete beams was conducted. The experimental program included seven large-scale T-beams reinforced with FRP and steel stirrups. Three beams were reinforced with CFRP stirrups, three beams reinforced with GFRP stirrups, and one beam reinforced with steel stirrups. The geometry of the T-beam was selected to simulate the New England Bulb Tee Beam (NEBT) that is being used by the Ministry of Transportation of Québec (MTQ), Canada. The beams were 7.0 m long with a T-shaped cross section measuring a total height of 700 mm, web width of 180 mm, flange width of 750 mm, and flange thickness of 85 mm. The large-scale T-beams were constructed using normal-strength concrete and tested in four-point bending over a clear span of 6.0 m till failure to investigate the modes of failure and the ultimate capacity of the FRP stirrups in beam action. The test variables considered in this investigation were the material of the stirrups, shear reinforcement ratio, and stirrup spacing. The specimens were designed to fail in shear to utilize the full capacity of the FRP stirrups. Six beams failed in shear due to FRP (carbon and glass) stirrup rupture or steel stirrup yielding. The seventh beam, reinforced with CFRP stirrups spaced at d /4, failed in flexure due to yielding of the longitudinal reinforcement followed by crushing of concrete. The effects of the different test parameters on the shear behaviour of the concrete beams reinforced with FRP stirrups were presented and discussed. The test results contributed to amending the shear provisions incorporated in the Canadian Highway Bridge Design Code (CAN/CSA-S6) and the updated provisions were approved in the CSA-S6-Addendum (CSA 2009). An analytical investigation was conducted to evaluate the validity and accuracy of available FRP codes and guidelines in Japan, Europe, and North America. The predictions of the codes and the guidelines were verified against the results of the tested beams as well as 24 other beams reinforced with FRP stirrups from the literature. The tested beams were also analysed using various shear theories including the modified compression field theory (MCFT), the shear friction model (SFM), and the unified shear strength model (USSM). A simple equation for predicting the shear crack width in concrete beams reinforced with FRP stirrups is proposed and verified against the experimentally measured values.
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Shehata, Emile F. G. "Fibre-reinforced polymer (FRP) for shear reinforcement in concrete structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/NQ41626.pdf.
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Quayyum, Shahriar. "Bond behaviour of fibre reinforced polymer (FRP) rebars in concrete." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/26242.
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Recently, fibre reinforced polymer (FRP) rebars have been extensively used in construction instead of steel rebars due to their non-corrosive nature and high tensile strength. Bond between FRP rebars and concrete is a critical design parameter that controls the performance of reinforced concrete members at serviceability and ultimate limit states. In order to prevent a bond failure, an adequate anchorage length should be provided. The anchorage length is derived using a bond stress-slip ( ) constitutive law. The objective of this study is to investigate the effect of different parameters such as the type of fibre, the rebar surface and the confinement provided by the transverse reinforcement on the bond behaviour of FRP rebars in concrete. Based on the analysis, a generalized bond stress-slip relationship will be developed and a new design equation for the required anchorage length of FRP rebar in concrete will be derived. A database was created on the bond stress-slip behaviour of FRP rebars in concrete from the available literature up to 2009. The data was statistically analyzed to investigate the effect of the different parameters on the bond performance of FRP rebars. It was observed that an increase in the confinement provided by the transverse reinforcement increased the bond strength of FRP rebars in concrete. This signifies that the presence of transverse reinforcement affects the bond behaviour of FRP rebars in concrete and hence, it should be taken into consideration while developing design equations for FRP rebars. Type of fibre and rebar surface does not affect the bond stress, but the latter affects the slip corresponding to the peak bond stress. Based on the results, a nonlinear regression analysis was performed to develop the bond stress-slip model for splitting mode of failure and a design equation for determining the development length of the FRP rebars in concrete was derived. The proposed development length equation can save about 10%-15% of the development length than that required by different code equations. This can save a considerable amount of FRP materials, which will eventually reduce the overall cost of construction and thereby, encourage the use of FRP reinforcing bars in the construction of concrete structures.
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Sudarisman. "Flexural behaviour of hybrid fibre-reinforced polymer (FRP) matrix composites." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/2110.
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The flexural behaviour of three different hybrid fibre-reinforced polymer (FRP) matrix composites, i.e. S2-glass/E-glass/epoxy, TR50S carbon/IM7 carbon/epoxy, and E-glass/TR50S carbon/epoxy hybrid FRP composites, has been investigated. The main objectives of this study were to: (i) improve the flexural properties of the parent composite materials, i.e. E-glass/epoxy and TR50S carbon fibre/epoxy composites, through substitution of stronger fibres, i.e. S2-glass and IM7 carbon fibres, for the fibres of the parent composite materials, and (ii) determine the optimum stacking configurations that produced the maximum increase in flexural properties of the resulting hybrid composites. In addition to these, two secondary objectives related to the preliminary investigation of determining the optimum stacking configurations have also been established. The two secondary objectives were to: (i) determine the optimum values of the processing parameters of the composites under investigation, and (ii) determine the compressive strength and compressive modulus of the parent materials.The investigation was carried out experimentally, thus data presented and analysed were obtained from laboratory work. Optimum values of five processing parameters, i.e. (i) the concentration of matrix precursor within the solvent solution utilised to wet the fibres, (ii) the compressive pressure applied during hotpress curing, (iii) the vacuum pressure of the atmosphere inside the curing chamber, (iv) the dwell time during hot-press curing, and (v) the holding temperature during hot-press curing, have been established. The criteria for determining the optimum values of these parameters were optimum fibre content, minimum void content, and optimum flexural properties. Compressive strength and compressive modulus of the parent composite materials have also been determined.Specimens were cut from flat composite plates using a diamond-tipped circular blade saw. The longitudinal edges of the specimens were carefully polished to remove any possible edge damage due to cutting. The composite plates were produced from preforms comprised of a number of glass fibre/epoxy prepregs, carbon fibre/epoxy prepregs or a combination of these. All the fabrication procedures were carried out using manual techniques. Whilst the compressive tests were conducted in accordance with the ASTM D3410-03 standard, flexural tests were carried out according to Procedure A of the ASTM D790-07 standard. Span-to depth ratios, S/d, of 16, 32, and 64 were selected for flexural testing in order to determine the minimum value of S/d required to ensure flexural failure rather than shear failure. Fibre and void contents were evaluated from optical micrograph images of the slices perpendicular to the fibre direction of the samples.It was concluded that the optimum values of the five processing parameters under investigations were: (i) epoxy concentration, C[subscript]e ~ 50 wt%, (ii) compressive pressure, p[subscript]c ~ 1.00 MPa, (iii) vacuum pressure, p[subscript]v ~ 0.035 MPa, (iv) dwell time, t ~ 30 minutes, and (v) holding temperature, T ~ 120 °C. Compressive tests revealed that the order of compressive strength for the parent composite materials were arranged as follows: S2-glass fibre/epoxy (476 MPa), E-glass fibre/epoxy (430 MPa), IM7 carbon fibre/epoxy (426 MPa), and TR50S carbon fibre/epoxy (384 MPa). The compressive modulus of these parent composite materials were found to be ordered as follows: IM7 carbon fibre/epoxy (67.9 GPa), TR50S carbon fibre/epoxy (61.8 GPa), S2-glass fibre/epoxy (45.1 GPa), and E-glass fibre/epoxy (32.9 GPa). After considering these compressive properties, three different hybrid combinations, as mentioned earlier, were manufactured and evaluated with the prepreg layers of the fibre composites possessing higher compressive strength being placed at the compressively loaded side of the flexural specimens.Shorter beam specimens (S/d = 16) of the three hybrid systems exhibited increased flexural strength as the amount of stronger fibre content was increased, but no hybrid effect was noted. The increase appeared to follow the rule of mixtures and this was attributed to their failure mode being shear failure. For beams tested at S/d = 32 and S/d = 64, the three hybrid systems demonstrated three different trends. The S2-glass fibre/E-glass fibre/epoxy hybrid system, where the S2-glass fibre (substituted at the compressive loading face) was slightly stronger and stiffer compared to the E-glass fibre at the tensile side, demonstrated increases in flexural strength together with the presence of a hybrid effect following partial substitution of the S2-glass fibre for E-glass fibres at the compressive side. The IM7 carbon fibre/TR50S carbon fibre/epoxy hybrid system, where the IM7 carbon fibre (substituted at the compressive side) was slightly stronger but significantly stiffer in compression compared to the TR50S fibre at the tensile side, exhibited a slight increase in flexural strength that appeared to obey the rule of mixtures.This result was attributed to the strength increase in the compressive side introduced by the substituted fibres not being sufficient to suppress the increase of internal compressive stress due to the increase in compressive modulus of the substituted fibres. The E-glass fibre/TR50S carbon fibre/epoxy hybrid system, where the E-glass fibre (substituted at the compressive side) was found to be slightly stronger but significantly less stiff in compression compared to the TR50S fibre at the tensile side, demonstrated a significant increase in flexural modulus and also exhibited a significant hybrid effect. The decrease in internal compressive stresses generated at the compressive side due to the decreased compressive modulus of the substituted fibre, when combined with the increase in compressive strength of the substituted fibre, was thought to led to the significant increase of flexural strength for this hybrid system.General trends observed in flexural modulus for the three hybrid systems were reasonably similar with any change in flexural modulus appearing to obey the rule of mixtures. Whilst an increase in flexural modulus was noted for higher contents of stronger fibre in the case of the S2-glass fibre/E-glass fibre/epoxy hybrid system and IM7 carbon fibre/TR50S carbon fibre/epoxy hybrid system, a decrease in flexural modulus with increased quantities of stronger fibre was exhibited by the E-glass fibre/TR50S carbon fibre/epoxy hybrid system. The increase or decrease in flexural modulus was attributed to the relative stiffness in compression of the substituted fibre when compared to that of the respective parent composite materials.Unlike the S2-glass fibre/E-glass fibre/epoxy hybrid system and IM7 carbon fibre/TR50S carbon fibre/epoxy hybrid system that did not exhibit any significant trend with regards the effect of the substitution of stronger fibre at the compressive side, the E-glass fibre/TR50S carbon fibre hybrid system demonstrated a significant increase in the energy stored to maximum stress with increasing content of the stronger fibre. This increase was mainly attributed to the increased strain–to-maximum stress of the hybrid system with respect to that of the parent composite material.In addition, for the three hybrid systems under investigation, the most significant change in flexural properties was noticed following substitution of the first layer at the compressive face. The relative position with respect to the neutral plane of the substituted layer was thought to be the reason for this phenomenon. It was also noted that flexural properties increased with the increase in S/d. A change in failure morphology was noted with the change of S/d from 16 to 32. It was thus determined that a S/d ratio of at least 32 was required in order to promote flexural failure (as opposed to shear failure). For the S2-glass fibre/E-glass fibre/epoxy hybrid system, this change appeared more obvious in comparison with that the other two hybrid systems with this change being accompanied by a significant increase in flexural strength.The main general conclusions that could be drawn from this investigation were that, although the flexural modulus appeared to obey the rule of mixture, an increase in flexural strength together with the presence of a hybrid effect, would most probably be observed when the fibre substituted at the compressive side possessed a significantly lower modulus combined with significantly higher compressive strength as demonstrated by the hybrid TR50S carbon - E-glass FRP composites. The most significant change in properties was exhibited by the first layer substitution whilst increasing the value of S/d resulted in an increase of flexural strength, with S/d = 32 being determined to be sufficient in order to promote flexural failure as opposed to shear failure.
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Huang, Da. "Structural behaviour of two-way fibre reinforced composite slabs." University of Southern Queensland, Faculty of Engineering and Surveying, 2004. http://eprints.usq.edu.au/archive/00001450/.
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Innovative new flooring systems utilising lightweight fibre reinforced polymer composite materials may have the significant potential to offer both economic and performance benefits for infrastructure asset owners compared to conventional concrete and steel systems. Over recent years, a range of prototype floor systems using fibre reinforced polymer composites have been developed by researchers at the University of Southern Queensland. However before such structural systems can be widely adopted by industries, fundamental understanding of their behaviour must be improved. Such work will allow for the development of new design and analysis procedures which will enable engineers to efficiently and accurately design and analyse such structures. This dissertation presents an investigation into a new two-way fibre reinforced composite floor slab system. The proposed new two-way slab system is, in essence, a sandwich structure with an innovative hollow core made from a castable particulate filled resin system. The key focus of this dissertation is the development of a new analysis tool to analyse the two-way fibre reinforced composite slab and facilitate subsequent parametric studies into slab configurations for concept refinement. The detailed 3D finite element analyses and experimental investigations are performed to verify the new analysis tool, and provide more detailed insight into the structural behaviour of this new two-way fibre reinforced composite slab. Comparisons with detailed 3D FEA and experiments illustrate that the simplified analysis tool is capable of providing sufficient accuracy for the preliminary analysis of a slab structure. Moreover, the 3D finite element analyses agree well with the experiments, and it is concluded that the behavioural responses of the proposed new slab structure can be reliably predicted. The experimental results show that this new slab concept exhibits quite a robust static behaviour and is likely to have a robust fatigue performance.
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Li, Shiqing. "FRP rupture strains in FRP wrapped columns." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6246.
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Applying lateral confinement to concrete columns using fibre-reinforced polymer (FRP) composites is a very promising technique. FRP rupture is the typical failure mode of FRP wrapped columns under axial compression. numerous experiments have shown that the FRP rupture strain in an FRP wrapped circular column is significantly lower than the FRP ultimate rupture strain determined from flat coupon test of FRP. Despite a large number of studies on the application of FRP confined columns, the mechanisms and level of lower-than-apparent FRP rupture strain still remain unclear. This thesis presents theoretical, Numerical and experimental studies aiming at developing a deeper understanding of the fundamental mechanisms of this phenomenon. A comprehensive literature review was presented providing the background on FRP confined columns, material properties of FRP composites as well as some factors which may lead to premature FRP rupture. A FE analysis was conducted to investigate the FRP hoop strains in the split-disk test, explaining for the first time that the fundamental mechanism of the lower FRP rupture strain in the split-disk test than in the flat coupon test is because strain localisation due to geometric discontinuities at the ends of the FRP and bending of the FRP ring at the gap due to change of curvature caused by the relative moment of the two half disks, as the FRP (as a brittle material) ruptures once the maximum strain at one of these locations reaches the FRP rupture strain. A list of contributory factors affecting the apparent FRP rupture strain in FRP wrapped columns were next identified and classified. An analytical solution was developed to investigate the influence of the triaxial stress state on the FRP strain efficiency, this factor has been shown to have a potentially significant effect on the failure of the FRP wrap but considerable discrepancies exist between predictions using different failure criteria so further research has been identified in this area. FE models were developed to examine the effect of the geometrical discontinuities on the strain efficiency of FRP jackets in FRP wrapped concrete-filled circular steel tubes and FRP wrapped concrete columns. It is demonstrated that severe FRP hoop strain concentrations occur in very small zones near the ends of the FRP wrap in both types of FRP wrapped columns, leading to premature FRP rupture and thus lower strain efficiency. The combined effects of end constraint and FRP overlap on the behaviour of FRP wrapped concrete columns was investigated using a three dimensional FE model considering one half of the length of an FRP-wrapped concrete cylinder. The results have shown that the frication between both ends of a column and the loading platens provides constraints to the ends of the column, but this constraint has little effect on the strain concentration caused by the geometrical discontinuities of the FRP overlap, though the ultimate axial strain of the FRP wrapped columns can be significantly overestimated if the end constraints are not considered.
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Youssef, Tarik A. "Time-dependent behaviour of fibre reinforced polymer (FRP) bars and FRP reinforced concrete beams under sustained load." Thèse, Université de Sherbrooke, 2010. http://savoirs.usherbrooke.ca/handle/11143/1941.
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An extensive experimental/research program has taken place at the University of Sherbrooke FRP Durability Facility. The program, consisting of four phases, studies the creep performance of FRP bars as well as the overall long-term behaviour of FRP reinforced concrete beams. Phase 1 deals with the creep performance of two types of GFRP bars subjected to different levels of sustained axial load; causing creep rupture at higher levels. In Phase 2, six different types of GFRP bars are tested under two levels of allowable service load, according to the currently available North American standards. The test duration, for the two phases, exceeded 10000 hours (417 days) wherein regular monitoring' of creep strain evolution took place and. the creep coefficient of GFRP bars was calculated. Residual tensile tests and microstructural analysis followed the long-term testing period. It was found that 45 % of the GFRP bars' tensile strength, fu,ave , is a safe limit for GFRP exhibiting sustained load, in standard laboratory conditions. Microstructural analysis shows that the increase in creep strain, after the 10000 hour period, is negligible for GFRP bars under allowable service load. Phase 3 consists of twenty reinforced concrete beams (ten pairs) comprising GFRP, CFRP, and steel reinforcing bars. The dimensions of which are 100 mm x 150 mm x 1800 mm, installed under third-point sustained load, for a period exceeding one year. Exhibiting a maximum applied moment of 25 % of their nominal moment capacity, Mn , all beams were regularly monitored in terms of (i) time-dependent deflection, (ii) strain increase in concrete and reinforcement and (iii) crack widths. Theoretical predictions for immediate deflection were calculated, using three methods (ACI 440.1R-06, CAN/CSA S806-02 and the ISIS Canda Design Manual (2007)), and compared to the obtained experimental results. Results showed that the calculations, regarding immediate deflection, under estimate by 67 %; underestimate by 10 %; overestimate by 11 %, for the aforementioned methods, respectively. The long-term to immediate deflection ratio, .l, was calculated for all beams and compared to ACI 440.1R-06 and CAN/CSA S806-02 predictions. Results showed that the North American standards are conservative as regards long-term deflection prediction. Immediate crack width results were compared to the prediction equations adopted by ACI 440.1R-06 and CAN/CSA S6-06, on the one hand, and by the ISIS Canada Design Manual (2007) on the other hand. Satisfactory results were found when the k b bond-coefficient factor is taken as 1.2 and 1.0, respectively. From the obtained data, the time-dependent kt multiplier, accounting for crack width increase after one year, was deduced as 1.7 and 1.5 for both models, respectively. Phase 4 deals with four full-scale GFRP reinforced concrete beams, of dimensions (215 mm x 400 mm x 4282 mm), subjected to uniform distributed load for a period of six months. Sizeable concrete blocks (of dimensions 610 mm x 762 mm x 1219 mm and weight = 13334 kN) were arranged on top of the beams to simulate sustained uniform distributed load. The main study parameters, of this phase, are (i) bottom reinforcement ratio and (ii) type of upper/compression reinforcement (GFRP and/or steel). The applied moment ranges from 15 to 21 % of the nominal moment capacity for the beams. Numerical modelling took place using a computer program (Fortran-2003) based on the age-adjusted effective modulus method, to predict the long-term deflection of the beams. The creep and shrinkage coefficients were calculated based on the ACI Committee 209 recommendations (1992) and CEB-FIP Model Code (1990). The theoretical curves were in very good agreement with the measured values. Furthermore, the empirical models available in ACI 440.1R-06 and CAN/CSA S806-02 were used for long-term deflection prediction. These predictions showed that both models can serve as upper bound and lower bound limits for the measured long-term deflection curves, respectively. As regards crack width prediction, the equations adopted by ACI 440.1R-06 (same as that of CAN/CSA S6-06) and by the ISIS Canada Design Manual (2007) yield satisfactory results when the kb bond-coefficient factor is 1.2 and 1.0 respectively (similar to phase 3). For both equations the time-dependent kt multiplier is deduced as 1.4, after six months.--Résumé abrégé par UMI.
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Haji, Kamis Haji Elmi Bin. "Three dimensional analysis of fibre reinforced polymer laminated composites." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/three-dimensional-analysis-of-fibre-reinforced-polymer-laminated-composites(0ba2ceae-129c-4d09-bdbd-de110e7b3617).html.
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The thesis presents the structural behaviour of fibre reinforced polymer (FRP) laminated composites based on 3D elasticity formulation and finite element modeling using Abaqus. This investigation into the performance of the laminate included subjecting it to various parameters i.e. different boundary conditions, material properties and loading conditions to examine the structural responses of deformation and stress. Both analytical and numerical investigations were performed to determine the stress and displacement distributions at any point of the laminates. Other investigative work undertaken in this study includes the numerical analysis of the effect of flexural deformation of the FRP strengthened RC slab. The formulation of 3D elasticity and enforced boundary conditions were applied to establish the state equation of the laminated composites. Transfer matrix and recursive solutions were then used to produce analytical solutions which satisfied all the boundary conditions throughout all the layers of the composites. These analytical solutions were then compared with numerical analysis through one of the commercial finite element analysis programs, Abaqus. Out of wide variety of element types available in the Abaqus element library, shells and solids elements are chosen to model the composites. From these FEM results, comparison can be made to the solution obtained from the analytical. The novel work and results presented in this thesis are the analysis of fully clamped laminated composite plates. The breakthrough results of fully clamped laminated composite plate can be used as a benchmark for further investigation. These analytical solutions were verified with FEM solutions which showed that only the solid element (C3D20) exhibited close results to the exact solutions. However, FEM gave poor results on the transverse shear stresses particularly at the boundary edges. As an application of the work above, it is noticed that the FEM results for the FRP strengthened RC slab, agreed well with the experimental work conducted in the laboratory. The flexural capacity of the RC slab showed significant increase, both at service and ultimate limit states, after FRP sheets were applied at the bottom surface of the slab. Given the established and developed programming codes, exact solutions of deflection and stresses can be determined for any reduced material properties, boundary and loading conditions, using Mathematica.
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Springolo, Mario. "New fibre-reinforced polymer box beam: investigation of static behaviour." University of Southern Queensland, Faculty of Engineering and Surveying, 2005. http://eprints.usq.edu.au/archive/00001513/.
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This thesis discusses the development of a new type of fibre-reinforced polymer (FRP) beam for use in civil engineering systems. After a detailed evaluation of the advantages and disadvantages of current FRP beam technology, a different approach is proposed which combines traditional laminates with a novel casting technique. To pre-dimension the beam, the classical beam theory is adapted to allow for FRP materials. The resulting formulae were used to determine critical parameters, such as laminate thickness and location in the cross-section, and core dimensions, and to identify failure modes. Based on the results of this analytical study, a detailed testing program was developed. In addition to classical tests, such as bending, shear, and lateral torsion, the performance of the beam was also examined under particular loading regimes specifically designed to induce local failure modes, such as buckling of the web and bearing failure of the section under concentrated loads. The experimental results revealed very good agreement with the analytical predictions. These results were corroborated by a detailed non-linear finite-element analysis, including core cracking and laminate damage. This analysis, in particular, highlighted the synergy between bending and shear behaviour of the beam. This study has revealed that this new type of FRP beam behaves in a predictable manner. Furthermore, the experimental results verified that the cross-section, which combines traditional laminates with cast polymer concrete, did not suffer from many of the disadvantages identified in current FRP beams. The cracking of the polymer concrete under shear, however, does cause the beam to fail prior to the laminates reaching their ultimate shear stress.
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Wong, Rita Sheung Ying. "Towards modelling of reinforced concrete members with externally-bonded fibre reinforced polymer, FRP, composites." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62958.pdf.
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Kalupahana, W. K. Kalpana G. "Anchorage and bond behaviour of near surface mounted fibre reinforced polymer bars." Thesis, University of Bath, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518298.
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The Near Surface Mounted (NSM) strengthening is an emerging retrofitting technique, which involves bonding Fibre Reinforced Polymer (FRP) reinforcement into grooves cut along the surface of a concrete member to be strengthened. This technique offers many advantages over external bonding of FRP reinforcement, for example, an increased bond capacity, protection from external damage and the possibility of anchoring into adjacent concrete members. To date, significant research has been conducted into the NSM FRP strengthening technique. However, there are still some areas which need further research in order to fully characterise bond and anchorage of NSM FRP bars. Lack of experimental data, design tools and analytical models addressing these areas create obstacles for the efficient use of these advanced polymer materials. The particular objectives of the research are; to investigate bond behaviour between NSM FRP bars and concrete, to understand the critical failure modes involved and their mechanics, and to develop a rational analytical model to predict bond strength and anchorage length requirements for NSM FRP bars. Several significant variables affecting bond, such as bond length, size, shape and type of bar, resin type, groove dimensions and concrete strength, have been considered. In particular, attention has been focussed on the effect of bar shape on bond behaviour. A comprehensive set of laboratory testing and their results, including the effect of the investigated parameters are presented. Various modes of anchorage failure of NSM FRP bars are identified and the underlying mechanics are investigated. Analytical models are developed to predict bond capacity and anchorage length requirements of NSM FRP bars, and are verified with experimental results.
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Barris, Peña Cristina. "Serviceability behaviour of fibre reinforced polymer reinforced concrete beams." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/7772.
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El uso de materiales compuestos de matriz polimérica (FRP) emerge como alternativa al hormigón convencionalmente armado con acero debido a la mayor resistencia a la corrosión de dichos materiales. El presente estudio investiga el comportamiento en servicio de vigas de hormigón armadas con barras de FRP mediante un análisis teórico y experimental. Se presentan los resultados experimentales de veintiséis vigas de hormigón armadas con barras de material compuesto de fibra de vidrio (GFRP) y una armada con acero, todas ellas ensayadas a flexión de cuatro puntos. Los resultados experimentales son analizados y comparados con algunos de los modelos de predicción más significativos de flechas y fisuración, observándose, en general, una predicción adecuada del comportamiento experimental hasta cargas de servicio. El análisis de sección fisurada (CSA) estima la carga última con precisión, aunque se registra un incremento de la flecha experimental para cargas superiores a las de servicio. Esta diferencia se atribuye a la influencia de las deformaciones por esfuerzo cortante y se calcula experimentalmente.Se presentan los aspectos principales que influyen en los estados límites de servicio: tensiones de los materiales, ancho máximo de fisura y flecha máxima permitida. Se presenta una metodología para el diseño de dichos elementos bajo las condiciones de servicio. El procedimiento presentado permite optimizar las dimensiones de la sección respecto a metodologías más generales.
Fibre reinforced polymer (FRP) bars have emerged as an alternative to steel for reinforced concrete (RC) elements in aggressive environments due to their non-corrosive properties. This study investigates the short-term serviceability behaviour of FRP RC beams through theoretical and experimental analysis. Twenty-six RC beams reinforced with glass-FRP (GFRP) and one steel RC beam are tested under four-point loading. The experimental results are discussed and compared to some of the most representative prediction models of deflections and cracking for steel and FRP RC finding that prediction models generally provide adequate values up to the service load. Additionally, cracked section analysis (CSA) is used to analyse the flexural behaviour of the specimens until failure. CSA estimates the ultimate load with accuracy, but it underestimates the experimental deflection beyond the service load level. This increment is mainly attributed in this work to shear induced deflection and it is experimentally calculated.
A discussion on the main aspects of the SLS of FRP RC is introduced: the stresses in materials, maximum crack width and the allowable deflection. A methodology for the design of FRP RC at the serviceability requirements is presented, which allows optimizing the overall depth of the element with respect to more generalised methodologies.
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ElGendy, Mohammed. "Punching shear behaviour of slab-column edge connections reinforced with fibre-reinforced polymer (FRP) composite bars." Canadian Society of Civil Engineering, 2014. http://hdl.handle.net/1993/24092.
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The use of fibre reinforced polymer (FRP) composites as an alternate to steel has proved to be an effective solution to the corrosion problem. However, FRP bars have low axial and transverse stiffness compared to steel bars which results in a lower shear capacity of FRP reinforced concrete (RC) elements compared to steel-RC elements.
Flat plate systems are commonly used to take advantages of the absence of beams. They, however, are susceptible to punching shear failure where the column suddenly punches through the slab.
An experimental program was conducted to investigate the punching shear behaviour of slab-column edge connections. Nine isolated full-scale slab-column edge connections were constructed and tested to failure. One connection was reinforced with steel flexural reinforcement, six with GFRP flexural reinforcement and two with GFRP flexural and shear reinforcement. The parameters investigated were the flexural reinforcement type and ratio, the moment-to-shear ratio and the shear reinforcement spacing.
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Morphy, Ryan David. "Behaviour of fibre-reinforced polymer (FRP) stirrups as shear reinforcement for concrete structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/MQ45102.pdf.
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Gai, Xian. "Fibre reinforced polymer (FRP) stay-in-place (SIP) participating formwork for new construction." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550617.
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The concept of stay-in-place (SIP) structural formwork has the potential to simplify and accelerate the construction process to a great extent. Fibre-reinforced polymer (FRP) SIP structural formwork offers further potential benefits over existing formwork systems in terms of ease and speed of construction, improved site safety and reduced long-term maintenance in corrosive environments. However, it is not without its limitations, including primarily the possibility of a lack of ductility, which is a key concern regarding the use of FRP structural formwork in practice. This thesis presents the findings of an experimental and analytical investigation into a novel FRP SIP structural formwork system for a concrete slab with a particular emphasis on its ability to achieve a ductile behaviour. The proposed composite system consists of a moulded glass fibre-reinforced polymer (GFRP) grating adhesively bonded to square pultruded GFRP box sections. The grating is subsequently filled with concrete to form a concrete-FRP composite floor slab. Holes cut into the top flange of the box sections allow concrete studs to form at the grating/box-section interface. During casting, GFRP dowels are inserted into the holes to further mechanically connect the grating and box sections. An initial experimental investigation into using GFRP grating as confinement for concrete showed that a significant increase in ultimate strength and strain capacity could be achieved compared to unconfined concrete. This enhanced strain capacity in compression allows greater use of the FRP capacity in tension when used in a floor slab system. Further experimental investigation into developing ductility at the grating/box-section interface showed that the proposed shear connection exhibited elastic-‘plastic’ behaviour. This indicated the feasibility of achieving ductility through progressive and controlled longitudinal shear failure. Following these component tests on the concrete-filled grating and the shear connectors, a total of six (300 x 150 x 3000) mm slab specimens were designed and tested under five-point bending. It was found that the behaviour of all specimens was ductile in nature, demonstrating that the proposed progressive longitudinal shear failure was effective. A three-stage analytical model was developed to predict the load at which the onset of longitudinal shear failure occurred, the stiffness achieved during the post elastic behaviour and, finally, the deflection at which ultimate failure occurred. Close agreement was found between experimental results and the theory.
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Shaia, Hussein Abed. "Behaviour of fibre reinforced polymer composite piles : experimental and numerical study." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/behaviour-of-fibre-reinforced-polymer-composite-piles-experimental-and-numerical-study(e4269c3e-0fe0-4e08-809c-bd764294b9a0).html.
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Fibre reinforced polymer (FRP) composites represent an alternative construction material for deep foundations that have the potential to eliminate most of the durability concerns associated with traditional piling materials. Research studies and database related to the use FRP composite material as piling foundation is very limited. This research project was undertaken to investigate the structural and geotechnical behaviour of FRP composite piles. The originality of this study rests on the following pillars:• Presenting a new understanding for the factors controlling the compressive strength of FRP tube confined concrete. • Introducing the concept of constitutive interface surface which considers the effect of surface hardness and relative roughness on the interface shear coefficient. • Studying the evolution of FRP pile surface roughness during the driving process. • Investigating the effect of harsh environments on the shear behaviour of FRP-granular interface. • Conducting an extensive experimental and numerical study to characterize the FRPs and soil parameters that control the behaviour of axially and laterally loaded FRP composite pile. Experimental testing program was conducted in this study to examine the behaviour of two different FRPs tubes confined concrete under axial compression, and flexural load. Based on the experimental results of this study and test results available in the literature, a new design chart was proposed to predict the strength enhancement based on concrete strength and FRP lateral confinement. An extensive laboratory study was conducted to evaluate the interface friction behaviour between granular materials and two different FRP materials. The interface test results obtained from experiment were used to examine a number of parameters known to have an effect on the interface friction coefficient. Furthermore, to investigate the evolution of FRP pile surface roughness during the driving process laboratory tests were also conducted to quantify the interface shear induced surface roughness changes under increased normal stress levels. Moreover, interface tests were also conducted using three more counterface materials to define schematically the constitutive interface shear surface (CISS) in the three dimensional domain of surface roughness, surface hardness, and interface shear coefficient. The long-term experimental program was also conducted in this study to assess the effect of different ageing environment conditions on FRP-granular interface shear coefficient. Acidic and alkaline aging environments were adopted in this study. The experimental program involved assessing the ageing effect on the testing FRP materials in terms of the changes in their hardness and surface roughness properties. Furthermore, the interface shear tests were conducted, using the unaged and aged FRP materials, to evaluate the effect of aging environments on FRP-granular interface shear coefficient. A small-scale laboratory pile loading tests were carried out to assess the FRP pile behaviour under axial and lateral loads. The laboratory test results were used to verify/validate a numerical model developed by the commercial finite element package ABAQUS (6.11). Additional numerical analyses using the verified model were conducted to investigate the effect of different the FRPs and soil parameters on the engineering behaviour of FRP pile.
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Schnerch, David Alan. "Shear behavior of large-scale concrete beams strengthened with Fibre Reinforced Polymer, FRP, sheets." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62842.pdf.
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Mahroug, Mohamed E. M. "Behaviour of continuous concrete slabs reinforced with FRP bars. Experimental and computational investigations on the use of basalt and carbon fibre reinforced polymer bars in continuous concrete slabs." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6332.
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An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections.
Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS¿M03¿07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440¿1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested.
On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment¿curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.
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Mahroug, Mohamed Elarbi Moh. "Behaviour of continuous concrete slabs reinforced with FRP bars : experimental and computational investigations on the use of basalt and carbon fibre reinforced polymer bars in continuous concrete slabs." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6332.
Full textAbstract:
An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections. Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS-M03-07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440-1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested. On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment-curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.
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Vilanova, Marco Irene. "Bond-slip and cracking behaviour of glass fibre reinforced polymer reinforced concrete tensile members." Doctoral thesis, Universitat de Girona, 2015. http://hdl.handle.net/10803/328720.
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In this work, a methodology has been developed to implement the bond behaviour between concrete and GFRP bars in the numerical modelling. Based on experimental results and applying the inverse method, the bond law to be used in the numerical model is obtained.
The thesis continues with two experimental campaigns on GFRP RC elements under tensile sustained loads. The first experimental campaign consisted in testing GFRP RC elements with different target concrete strengths. The tests were carried out for a period between 35 a 39 days. Experimental results were compared with analytical codes for steel RC structures. The second experimental campaign consists on the analysis of bond of such structures under sustained load. The specimens were tested for a period between 90 and 130 days. Slip stabilization was observed to occur at 60 days after the beginning of the tests.En aquest treball s’ha desenvolupat una metodologia que permet la implementació del comportament adherent entre formigó i barres de material compost en la modelització numèrica. A partir de resultats experimentals i aplicant un mètode invers s’obtenen les lleis d’adherència aptes per ser incorporades a la modelització numèrica. Com a continuació de l’estudi s’han portat a terme dues campanyes experimentals en elements sotmesos a càrrega de tracció mantinguda. La primera campanya experimental va consistir en l’assaig de tirants de formigó variant la resistència del formigó. Els espècimens van estar sotmesos a càrrega mantinguda durant un període de 35-39 dies. Els resultats es van comparat amb models analítics existents per reforç estructural d’acer. En la segona campanya experimental es va aprofundir en l’estudi de l’adherència a llarg termini. Els espècimens van estar sotmesos a càrrega mantinguda durant un període de 90-130 dies observant una estabilització del lliscament 60 dies després de l’inici dels assaigs.
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Li, Xiaoqin. "FRP-to-concrete bond behaviour under high strain rates." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6234.
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Fibre reinforced polymer (FRP) composites have been used for strengthening concrete structures since early 1990s. More recently, FRP has been used for retrofitting concrete structures for high energy events such as impact and blast. Debonding at the FRP-to-concrete interface is one of the predominant failure modes for both static and dynamic loading. Although extensive research has been conducted on the static bond behaviour, the bond-slip mechanics under high strain rates is not well understood yet. This thesis is mainly concerned with the FRP-to-concrete bond behaviour under dynamic loading. Because debonding mostly occurs in the concrete adjacent to the FRP, the behaviour of concrete is of crucial importance for the FRP-to-concrete bond behaviour. The early emphasis of this thesis is thus on the meso-scale concrete modelling of concrete with appropriate consideration of static and dynamic properties. Issues related to FE modelling of tensile and compressive localization of concrete are first investigated in detail under static condition using the K&C concrete damage model in LS-DYNA. It is discovered for the first time that dilation of concrete plays an important role in the FRP-to-concrete bond behaviour. This has led to the development of a model relating the shear dilation factor to the concrete strength based on the modelling of a large number of static FRP-to-concrete shear tests, forming the basis for dynamic modelling. Concrete dynamic increasing factor (DIF) has been a subject of extensive investigation and debate for many years, but it is for the first time discovered in this study that mesh objectivity cannot be achieved in meso-scale modelling of concrete under high strain rate deformation. This has led to the development of a mesh and strain rate dependent concrete tension DIF model. This DIF model shall have wide applications in meso-scale modelling of concrete, not limited to the topic in this thesis. Based on a detailed numerical investigation of the FRP-to-concrete bond shear test under different loading rates, taking on the above issues into careful consideration, a slip rate dependent FRP-to-concrete dynamic bond-slip model is finally proposed for the first time. The FE predictions deploring this proposed bond-slip model are compaed with test results of a set of FRP-to-concrete bonded specimens under impact loading, and a FRP plated slab under blast loading, validating the model.
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Mohamamdpour, Lima Mehdi. "Experimental and Numerical Study of RC Walls with Opening Strengthened by CFRP." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/367903.
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Concrete structures regularly require strengthening due to various reasons. These structures include bridges, buildings and infrastructure, across numerous sectors and industries. Based on the load-carrying capacity of structures and proposed future applications, a vast array of strengthening methods may be utilised. Due to rapid advancements in construction materials, technology has led to the achievement of being able to secure safer, more economical and functional buildings. Of the innovative materials, Fibre Reinforced Polymer (FRP) appears to be an encouraging solution for the retrofitting and strengthening of Reinforced Concrete (RC) structures because of its unique properties. These properties include: high strength-to-weight ratio; high fatigue endurance; environmental degradation and corrosion resistance. FRP is also durable and very flexible for application to the various shapes of structural members. Further, it is easy to install, with a negligible increase in structural size and weight. The application of FRP is dependent upon the type of structural member plus its behaviour. It can be used to enhance the load capacities (axial, flexural, or shear), ductility, rigidity, the remaining fatigue life as well as the durability against harsh environments.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
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Rahman, S. M. Hasanur. "Flexural behavior of GFRP-reinforced concrete continuous beams." American Society of Civil Engineers, 2016. http://hdl.handle.net/1993/31905.
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In this study, a total of twelve beams continuous over two spans of 2,800 mm each were constructed and tested to failure. The beams were divided into two series. Series 1 included six T-beams under symmetrical loading, while Series 2 dealt with six rectangular beams under unsymmetrical loading conditions. In Series 1, the test variables included material type, assumed percentage of moment redistribution, spacing of lateral reinforcement in flange, arrangement of shear reinforcement, and serviceability requirements. In Series 2, three different loading cases were considered, I) loading both spans equally, II) loading both spans maintaining a load ratio of 1.5 and III) loading one span only. Under the loading case II, the parameters of reinforcing material type, assumed percentage of moment redistribution and serviceability requirements were investigated.
The test results of both series showed that moment redistribution from the hogging to the sagging moment region took place in GFRP-RC beams which were designed for an assumed percentage of moment redistribution. In Series 1, the decrease of the stirrups spacing from 0.24d to 0.18d enhanced the moment redistribution percentage. Also, decreasing the spacing of lateral reinforcement in the flange from 450 to 150 mm improved the moment redistribution through enhancing the stiffness of the sagging moment region. In Series 2, the unsymmetrical loading conditions (loading case II and III) reduced the moment redistribution by reducing flexural stiffness in the heavily loaded span due to extensive cracking. Regarding serviceability in both series, the GFRP-RC beam designed for the same service moment calculated from the reference steel-RC beam, was able to meet the serviceability requirements for most types of the structural applications.February 2017
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Juan, Muñoz Jaime. "Development of the in situ forming of a liquid infused preform (ISFLIP) process : a new manufacturing technique for high performance fibre reinforced polymer (FRP) components." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/457775.
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A problem is not a problem anymore if no solution exists; therefore, in the present dissertation, a novel manufacturing technique, the In Situ Forming of a Liquid Infused Preform (ISFLIP), is proposed as a solution to some typical problems that manufacturing of Fibre Reinforced Polymer (FRP) parts through Vacuum Infusion (VI) involves, such as not taking advantage of the full potential of FRPs, long processing times and lack of reproducibility.
ISFLIP is a hybrid process between VI and diaphragm forming in which a flat preform of a stack of reinforcement fabrics is firstly impregnated with a low viscosity matrix and, then, formed over a mould while the matrix is still in the low viscosity state. Being focused on high performance FRPs and shell components, from simple to complex double curvature shapes, a number of trade-offs between VI and diaphragm forming were overcome to lay the foundations from which ISFLIP ability to manufacture FRP components has been proven.
In order to adopt a VI manufacturing methodology that fitted ISFLIP targets, important contributions to more general VI have also been made in terms of part quality optimization, addressing the major concern that void content is in VI, with competitive manufacturing times. An effective vacuum degassing procedure in which bubble formation is enhanced through high speed stirring, and a non-conventional filling and post-filling strategy are proposed for this purpose. Eventually, void content was virtually eliminated and post-filling time minimized without affecting fibre content.
In ISFLIP, textile preforms are formed together with a series of auxiliary materials (plastic films and sheets, textile fabrics and knitted meshes), most of them showing different in-plane deformation mechanisms. Forming performance of preforms, as well as final part quality, are severely affected by interactions between all these materials different in nature. Uncertainties on this respect and an initial evaluation of attainable shapes were also addressed to define a more focused research plan to the final goal, still distant, of implementing ISFLIP in a real production environment.
Results obtained throughout the research project give cause for reasonable optimism in ISFLIP potential and future prospects.Un problema deja de ser un problema si no existe solución; por lo tanto, en esta disertación, una novedosa técnica de fabricación, el Conformado In Situ de una Preforma Infusionada con resina Líquida (ISFLIP, por sus siglas en inglés), se propone como solución a algunos problemas típicos relacionados con la fabricación de piezas de Polímero Reforzado con Fibra (FRP) a través de la Infusión por Vacío (VI), problemas tales como el desaprovechamiento de todo el potencial de los FRPs, largos tiempos de procesado y falta de reproducibilidad. ISFLIP es un proceso híbrido entre la VI y el conformado por membrana elástica en el que una preforma plana formada a partir de un apilado de tejidos de refuerzo es en primera instancia impregnada con una resina de baja viscosidad y, entonces, conformada sobre un molde mientras que la matriz permanece todavía en el estado de baja viscosidad. Estando centrado en los FRPs de altas prestaciones y en componentes con formas tipo concha, desde curvaturas simples hasta formas con doble curvatura complejas, un número importante de compensaciones entre la VI y el conformado por membrana se han ido superando para asentar las bases a partir de las cuales se ha probado la capacidad de ISFLIP para fabricas componentes de FRP. Con la vista puesta en implementar una metodología de fabricación por VI que cumpliese los objetivos definidos para ISFLIP, también se han realizado importantes contribuciones de carácter más general relacionadas con la VI en términos de optimización de parámetros de calidad de las piezas, abordando la gran preocupación que la porosidad final supone en la VI, y consiguiendo unos tiempos de fabricación competitivos. Con este propósito se han propuesto un proceso de desgasificación por vacío muy efectivo en el que se favorece la nucleación de burbujas mediante la agitación a alta velocidad, y una prometedora y no convencional estrategia de llenado y post-llenado de la preforma. Finalmente, se consiguió virtualmente eliminar la porosidad atrapada en las piezas, minimizando el tiempo de post-llenado sin afectar la fracción de fibra contenida. En ISFLIP las preformas textiles se conforman junto con una serie de materiales auxiliares (films y hojas plásticas, mallas y tejidos textiles), que muestran diferentes mecanismos de deformación en plano. El conformado de las preformas y el acabado final de las piezas se ve severamente afectado por todas las interacciones entre todos estos materiales diferentes en naturaleza. También se han abordado las incertidumbres que surgen al respecto y una evaluación inicial de las geometrías abarcables para definir un plan de investigación más concreto con el que poder afrontar la meta final, todavía distante, de implementar ISFLIP en un entorno productivo real. Los resultados obtenidos a lo largo de este proyecto de investigación permiten ser razonablemente optimistas en cuanto al potencial de ISFLIP y sus expectativas.
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Tafsirojjaman, Tafsirojjaman. "Mitigation of seismic and cyclic loading actions on steel structures by FRP strengthening." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/207918/1/Tafsirojjaman_Tafsirojjaman_Thesis.pdf.
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This thesis aimed to develop an effective technique to mitigate the cyclic and seismic loading actions on steel structure by FRP strengthening. Extensive study has been done to understand the structural performance of FRP strengthened steel members, beam-column connections under monotonic and cyclic loading and FRP strengthened steel frames under seismic loading through experimental testing, finite element (FE) modelling and theoretical approach. The developed finite element and theoretical model predicted the structural responses of FRP strengthened steel structures accurately. The results showed that the FRP strengthening can effectively mitigate the cyclic and seismic loading actions on the steel structure.
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Römhild, Stefanie. "Transport Properties and Durability of LCP and FRP materials for process equipment." Doctoral thesis, KTH, Polymera material, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13221.
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This thesis focuses on transport properties and durability of liquid crystalline polymers (LCP)and fibre reinforced plastics (FRP) with regard to application in industrial process equipment.In the first part of the study the possibility of using a thermotropic LCP of type Vectra A950as lining material for FRP process equipment was investigated. Its performance wascompared to that of a fluorinated ethylene propylene copolymer (FEP) with respect tochemical and permeation resistance. Transport property and chemical resistance data wereestablished for different types of LCP film (compression molded, uniaxially and biaxiallyoriented film) exposed to selected chemicals chosen to represent typical industrial processenvironments. Annealing of the LCP, which may reduce the disclination density and henceimprove the barrier properties, induced a crystallinity increase, but did not significantlyimprove the barrier and chemical resistance properties. Different surface treatments toincrease the bonding between the LCP and FRP were explored. The conclusion was that LCPhas potential to serve as lining material for FRP in contact with water, organic solvents andnon-oxidizing acid environments, although certain issues, such as jointing techniques, stillhave to be evaluated. The second part of the study focused on transport and long-termproperties of commercial thermoset and FRP materials for industrial process equipment inaqueous environments (50 – 95 °C, water activity 0.78 – 1, exposure time ≤ 1000 days). Thewater transport properties in different thermosets were related to their chemical structureusing the solubility parameter concept. The transport of water in the thermosets with differentchemical structures could be predicted from the water activity, regardless of the actual type ofionic or non-ionic solute in the solution. An empirical relationship, independent of boththermoset chemistry and temperature, was established to describe the water concentration inthe thermoset as a function of water activity and the water concentration in pure water. Inlong-term, the water concentration in the thermosets increased with exposure time. Thisseemed to be primarily related to stress relaxation processes induced by water absorption andcertain leaching effects. The effects of hydrolysis seemed to be small. The glass fibrereinforcement may to various extents affect the water transport properties by capillarydiffusion and additional absorption around fibre bundles. The extent of such processesseemed to depend on temperature, water activity and the type of thermoset and reinforcement.The present work may be a useful contribution to an increased understanding of water effectsand durability of FRP process equipment. However, open questions still remain for a morecomprehensive durability analysis.QC20100629
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Homam, Sayed Mukhtar. "Durability of fibre-reinforced polymers (FRP) used in concrete structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0023/MQ50345.pdf.
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Talukdar, Sudip. "Strengthening of timber beams using externally-bonded sprayed fibre reinforced polymers." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/920.
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The use of Fibre Reinforced Polymers (FRP) has grown in popularity in the construction industry. FRP has proven useful in the retrofit of various types of structural elements. It may be used for the strengthening of beams, the seismic upgrade of walls panels, as well as the jacketing of columns to provide confinement. There exist several methods of FRP application for the case of structural retrofits. These include the application of pre-prepared FRP mats, or application of FRP via the wet lay-up process. However, a new technique developed at the University of British Columbia allows for the application of FRP in the form of a spray.
Externally bonded Sprayed FRP (SFRP) is known to increase strength and energy absorption capacity of a retrofitted member as well as, or better than, FRP sheets. However, tests have primarily been carried out on concrete members only. An area of interest, into which not much research has been conducted, is the application of SFRP to timber. Timber bridges are extensively used in many parts of the world. Often due to remoteness and practical constraints, it is impossible to apply FRP sheets to retrofit these bridges. SFRP would be a much easier method of FRP application.
This study looked at the application of SFRP to Douglas Fir (D.Fir) Beam specimens subjected to 3-Point Flexural Loading only. The specimens were treated with either a water based (Borocol) or oil borne (Creosote) antifungal preservative prior to being sprayed with FRP. Different combinations of adhesives/bonding agents including Hydroxymethylated Resorcinol and Polymeric Isocyanates were used to try to develop a strong bond.
When considering using only chemical adhesives to obtain a proper bond between the two constituents of the composite, use of HMR is recommended for timber which is untreated or has been treated with a water borne preservative such as Borocol, while a pMDI adhesive such as AtPrime 2 is recommended for timber treated with an oil borne preservative such as Creosote. For Non Creosoted beams, adhesives did not generate as significant of a strength gain. For Creosoted beams, adhesives may be sufficient to generate significant strength gain when SFRP is applied to a beam. Considering that most structures in use would probably have been treated with a preservative similar to Creosote, in practice, AtPrime 2 or some other some sort of pMDI would probably be the adhesive of choice.
Based on the results of the study, it is possible to say that the application of SFRP to retrofit/rehabilitate timber structures shows considerable promise. If a decent bond is achieved between the composite constituents, it is possible to substantially increase the ultimate flexural strength of the member, as well as drastically increase its ductility and energy absorption capacity. It is recommended that further tests be carried out using different types of loading schemes, geometrical configurations of SFRP, other types of anchorage, and development of a proper analytical model before the method is adopted for widespread use.
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Bártová, Denisa. "Využití moderních kompozitních materiálů při návrhu betonových konstrukcí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409787.
Full textAbstract:
This diploma thesis deals with the design of FRP reinforced concrete structures. The theoretical part is focused mainly on the punching shear of a flat two way slab according to ACI, fib Bulletin, CSA, and JSCE standards. This thesis also includes a description of the punching shear resistance according to Eurocode 2. FRP reinforcement, its mechanical properties, and their behaviour in time are also described. Next, a parametric study was performed that examines the effects of various parameters on the punching shear resistance according to the standards mentioned above. At the end a non-linear analysis using the ATENA software was performed. The practical part includes a structural design of a flat two way slab. The slab uses a steel reinforcement at the bottom, while the top is reinforced with FRP reinforcement. The punching shear design is also included. In the last chapter the serviceability limit state is checked, specifically the slab long-term deflection. The thesis also includes drawings. All calculations were performed in accordance with Eurocode 2 and fib Bulletin No. 40.
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Baena, Muñoz Marta. "Study of bond behaviour between FRP reinforcement and concrete." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/7771.
Full textAbstract:
El uso de barras de materiales compuestos (FRP) se propone como una alternativa efectiva para las tradicionales estructuras de hormigón armadas con acero que sufren corrosión en ambientes agresivos. La aceptación de estos materiales en el mundo de la construcción está condicionada a la compresión de su comportamiento estructural. Este trabajo estudia el comportamiento adherente entre barras de FRP y hormigón mediante dos programas experimentales. El primero incluye la caracterización de la adherencia entre barras de FRP y hormigón mediante ensayos de pull-out y el segundo estudia el proceso de fisuración de tirantes de hormigón reforzados con barras de GFRP mediante ensayo a tracción directa. El trabajo se concluye con el desarrollo de un modelo numérico para la simulación del comportamiento de elementos de hormigón reforzado bajo cargas de tracción. La flexibilidad del modelo lo convierte en una herramienta flexible para la realización de un estudio paramétrico sobre las variables que influyen en el proceso de fisuración.The use of Fibre Reinforced Polymers (FRP) as reinforcement in concrete structures is considered to be a possible alternative to steel in those situations where corrosion is present. The full acceptance of FRP reinforcement in concrete construction is contingent on a complete study and comprehension of all aspects of their structural performance. This thesis investigates the bond behaviour between Fibre Reinforced Polymer (FRP) reinforcement and concrete. Two experimental programs were conducted. In the first program the role of the variables which affect the bond behaviour was studied through pull-out test. In the second program, GFRP RC members were tested in tension to study their cracking response. To conclude the thesis, a numerical model was developed to simulate the cracking behaviour of RC tensile members. Since the model was flexible enough to include any "user-defined" bond-slip law and variable materials' properties, a parametric study was conducted to analyze which are the variables that influence the cracking behaviour.
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Hallonet, Anne. "Développement et caractérisation d'un matériau composite à base de fibres de lin : application au renforcement de structures en béton par collage externe." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1111/document.
Full textAbstract:
Afin de prolonger leur durée de vie et d'assurer la sécurité des usagers, les structures en béton peuvent nécessiter un renforcement au cours de leur durée de service. La technique de renforcement par collage externe, en surface, de composites renforcés de fibres de carbone, de verre ou d'aramide à l'aide de résines durcissant à température ambiante est largement employée pour son efficacité et sa facilité de mise oeuvre. Toutefois l'utilisation à la fois de fibres synthétiques et de matrices polymères produit un impact écologique non négligeable. L'objectif de ce travail de recherche est d'examiner la possibilité d'utiliser des fibres de lin pour le renforcement externe de structures en béton. Les propriétés mécaniques spécifiques et le bilan environnemental avantageux des fibres de lin en font une alternative intéressante aux fibres de verre. Cependant leur origine naturelle conduit à une plus grande variabilité des propriétés, à un comportement en traction non linéaire et une sensibilité accrue à l'humidité. Les principaux objectifs du travail de thèse portent ainsi sur la sélection des matériaux et la mise en oeuvre les plus adaptés, sur l'évaluation des performances du matériau et de son adhérence au support béton et sur une évaluation de la durabilité des propriétés du système. Dans une première partie expérimentale deux méthodes de mise en oeuvre du renfort à fibres de lin (stratification au contact et collage de lamelles rigides) sont développées et caractérisées. Des observations tomographies X confirment la bonne imprégnation des fibres et la cohésion des composites. Les essais de traction révèlent un comportement en traction bilinéaire comme décrit dans la littérature, avec des propriétés d'effort par largeur de bande comparables aux composites de renfort à fibres de verre. La caractérisation des interfaces composite/béton menée par tests de cisaillement à double recouvrement confirme une bonne adhérence qui se traduit par une rupture cohésive dans le substrat béton. La nature des fibres ne semble pas influencer le comportement de l'interface. Les systèmes de renforcement à fibres de lin sont donc capables de reprendre des efforts transmis par cisaillement de façon comparable aux matériaux de renfort à fibres de verre. Dans une deuxième partie des essais exploratoires de durabilité ont ensuite été menés pour vérifier la pérennité des propriétés de ces deux composites de renfort dans un environnement de service. Un vieillissement accéléré artificiel en enceinte climatique est mis en place tandis que des composites à fibres de lin stratifié au contact sont exposés pendant un an à l'environnement extérieur. Un second vieillissement hygrothermique à 70°C est mené pendant 4 semaines. Les dégradations des propriétés des composites à fibres de lin sont comparables à celles de certains composites de renfort à fibres de verre. Malgré la nature hydrophile des fibres de lin, les premiers essais ne montrent pas de dégradations des propriétés qui rendraient le composite impropre à une utilisation comme renfort extérieur de structures en bétonTo extend their life and ensure the safety of users, concrete structures may need strengthening during their service life. The technique of strengthening by external bonding of composites carbon, glass or aramid composites using polymer that are cured at room temperature is widely used for its effectiveness and ease of implementation. Yet the uses of both synthetic fibers and polymer matrices have a significant environmental impact. The objective of this research is to examine the possibility of using flax fibers for the external strengthening of concrete structures. Their high specific mechanical properties and positive environmental balance make them an interesting alternative to the glass fibers. However, they also present a larger variability in properties, a non-linear tensile behavior and high sensitivity to humidity. The main objectives of this thesis involve the selection of the materials and the most suitable implementation, the evaluation of the materials’ performances and adherence to concrete support and a sustainability assessment of those properties. In a first experimental section, two methods of implementation of the flax fiber reinforcement are developed and characterized: by wet lay-up and by bonding of pre-hardened. Tomography observations confirm the good fiber impregnation and cohesion of the composites. The tensile tests show a bilinear tensile behavior as described in the literature, with stress per width at failure comparable to glass fibres strengthening systems. The characterization of composite/concrete interfaces is conducted by double overlap shear tests and confirms a good adhesion which results in concrete failure before the failure of the reinforcement system. The nature of the fibers does not appear to influence the shear behavior of the interface. For glass or flax wet lay-up systems, failure can occur with failure of the composite. Flax fiber reinforcement systems can take up the forces transmitted by shear in a manner comparable to glass composites. In the second part, sustainability tests were conducted to ensure the sustainability of the properties of these two composite reinforcements in a service environment. An artificial accelerated aging test in a climatic chamber is set up while wet lay-up flax fiber composites are exposed to the external environment during a year. A second hydrothermal aging test is conducted for 4 weeks at 70°C. The degradations of the properties of the flax composites are comparable to those of some glass reinforcement composites. Despite the hydrophilic nature of the flax fibers the first tests show no degradation of properties that would make the composite unsuitable for an external reinforcement of concrete structures
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Matušíková, Anna. "Navrhování konstrukcí s FRP výztuží." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225478.
Full textAbstract:
This diploma thesis presents available FRP software for calculating load bearing capacity of the structures reinforced with FRP and compares them between each other. Furthermore theory and algorithm of my own software is presented here. Load bearing capacity of structures which are reinforced with non-metallic reinforcement and loaded by combination of normal force and bending moment can be solved by my programme. Effects of high temperatures on the concrete structures can be included in the calculation. In the second part of the thesis is calculated load-bearing capacity and deflection of the real beam reinforced with FRP reinforcement and load-bearing capacity of member with FRP reinforcement with effect of elevated temperature. This has been done using my software. Comparison of results from hand calculation and laboratory load-bearing testing is done at the end. This laboratory testing was accomplished by Institute of Concrete and Mansory Structures at our faculty.
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Caggegi, Carmelo. "Experimental analysis of the efficiency of carbon fiber anchors applied over CFRP to firebrick bonded joints." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1025/document.
Full textAbstract:
Dans les dernières années, le renforcement des bâtiments en maçonnerie a connu une usure massive des bandes CFRP. Ces matériaux composites, attachés sur les éléments à renforcer, sont exposés à une fracture prématurée pour délaminage (...). Une façon pour accroître la résistance maximale du système renforcé par CFRP est d'améliorer la cohésion entre support et composite en utilisant des ancrages mécaniques. Ces derniers sont réalisés en utilisant les mêmes typologies de fibres de renforcement et en les insérant dans le support comme des «clous». Les recherches scientifiques sur l'usure de cette façon d'ancrage sur support en maçonnerie ont été très limitées et, dans ce contexte, il n'y a pas d'études expérimentales sur le projet et le placement des ancrages. L'objectif principal du présent travail de thèse est de quantifier l'efficacité des ancrages en fibre de carbone appliqués sur brique (...) par les bandes CFRP. Cette recherche est la première phase d'une étude plus vaste sur les systèmes de maçonnerie-CFRP renforcés par « carbon fiber anchor ». Dans l'étude, l'analyse des déplacements et des déformations de la surface renforcée a été faite en utilisant la Corrélation des Images (DIC), une avantageuse méthode optique jamais utilisée pour l'étude des systèmes «support-CFRP band- ancrages».Le présent travail de thèse démontre que les ancrages en CFRP augmentent le résistance maximale et la ductilité des renforcements par bande de composites. Donc, cette typologie d'ancrage augmente la sécurité des personnes pendant les tremblements de terre et ne permettent pas la fracture fragile de la structure renforcée. La corrélation des images a été un bon outil pour l'étude des déformations, des avantages et des inconvénients de cette méthode et ont été évalué pendant la rechercheIn these recent years, the strengthening of masonry building has known a massive use of CFRP sheets. Those composite materials glued on the elements to reinforce are exposed to prematurely debonding crisis due to a tension load which is much smaller than the tensile strength of the CFRP. A way to upgrade failure load of CFRP-to-support bonded joint is to reinforce the cohesion between the fibers and the support by the use of mechanicals anchors built with the same fibers of the composite and fastened in the support like “nails”. Research on the use of anchors for masonry supports has been limited and, in this framework, there are no experimental analyses related to the design and the placement of fiber anchors. The aim of this thesis is to provide experimental data to quantify the efficiency of the carbon fiber anchors applied on a reinforced fire brick. This is a ground work to study CFRP to masonry bonded joint fastened by fiber “nails”. Specifically, the analysis of the displacement and the strain fields of the reinforced surface have been realized by means of Digital Image Correlation (DIC), an optical appealing method never used to study a FRP to support bonded joint fastened by FRP anchor. The research demonstrates that the use of the CFRP anchor increases the resistance and the ductility of the reinforcements. The latter are important to augment the mechanical features of the structural members and, especially, to increase the safety of people during earthquakes by avoiding the brittle collapse of the strengthened elements. The digital image correlation has been a good tool for the strain field analysis; strengths and weaknesses of this method have been evaluated
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Andreou, Eftychia. "Performance evaluation of RC flexural elements strengthened by advanced composites." Thesis, University of South Wales, 2002. https://pure.southwales.ac.uk/en/studentthesis/performance-evaluation-of-rc-flexural-elements-strengthened-by-advanced-composites(f441fa99-6428-46c2-8053-8e362546044c).html.
Full textAbstract:
The flexural performance of composite systems made of reinforced concrete, Fibre Reinforced Polymers (FRPs) and adhesives was studied during the current research. The experimental investigation was principally concentrated on the potential use of Kevlar® 49 (aramid fibre) for RC beam strengthening. The main aims of research have been; (a) to investigate the relative merits of using Aramids in comparison to other FRPs, (b) strength optimisation of systems to prevent excessive losses of ductility, (c) to examine the failure mode and crack patterns, together with salient strength factors at ultimate limit state and (d) to carry out analytical modelling using a commercial FE package. The experimental investigation comprised of testing 55 simply supported RC beams of either 1.5m or 2.6m length. In addition to the parametric studies included in points (a)-(d) above (to assess the section characteristics), further experimentation was conducted to investigate the beam performance by varying the factors of; (e) beam shear span, (f) FRP anchorage length, (g) concrete surface preparation, (h) FRP end-anchoring, (i) beam precracking, (j) introduction of air-voids within the bond line of FRP/concrete, (k) influence of cyclic loading and, (1) exposure to aggressive environment. The results from current tests confirm elements of reports from other researchers (by thorough review of literature) that all FRPs have great potential for flexural strengthening of RC members. This is valid even in cases where additional environmental degradation and/or cracking (due to serviceability loads), had taken place. Aramid fibres were found to result in favourable outcomes concerning both strength and ductility enhancements. It was determined, both from experiments and non-linear modelling, that the amount of FRP fibre content is an important factor in every strengthening application. Experimentation showed that depending on the existing condition of the structure (concrete strength, internal reinforcement ratio, section dimensions, degradation level and load configuration), there seems to be a unique level of optimum fibre content. The FRP levels in excess of the optimum were seen to lead to premature brittle tearing-off failure modes. It was also found that to prevent premature beam failure (due to incompatibility of stress at concrete and FRP interface), a maximum possible anchorage length should be considered in order to deliver an optimum section performance. The results from the analytical modelling indicated a most satisfactory agreement with the experimental data after the initial mechanical properties were calibrated. It was found that actual representation of material properties (e.g. steel constitutive law) are of great significance, for an accurate modelling of RC element loaded behaviour. The bond developed between the FRP and concrete is one of the key parameters for achieving good performance of the systems. It was determined that concrete surface preparation and priming is beneficial, while the introduction of air-voids due to poor workmanship can reduce the section load bearing capabilities. Cyclic loading on FRP strengthened sections was found to curtail the full rotational capacity utilisation of the beam. However, even the above mentioned curtailed behaviour was more advantageous than cyclically loaded beam performance without FRP strengthening.
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Caggegi, Carmelo. "Experimental analysis of the efficiency of carbon fiber anchors applied over CFRP to firebrick bonded joints." Doctoral thesis, Università di Catania, 2013. http://hdl.handle.net/10761/1410.
Full textAbstract:
In these recent years, the strengthening of masonry building has known a massive use of CFRP sheets. Those composite materials glued on the elements to reinforce are exposed to prematurely debonding crisis due to a tension load which is much smaller than the tensile strength of the CFRP. A way to upgrade failure load of CFRP-to-support bonded joint is to reinforce the cohesion between the fibers and the support by the use of mechanicals anchors built with the same fibers of the composite and fastened in the support like nails . Research on the use of anchors for masonry supports has been limited and there are no experimental analyses related to the design and the placement of fiber anchors.
The aim of this thesis is to provide experimental data to quantify the efficiency of the carbon fiber anchors applied on a reinforced fire brick. This is a ground work to study CFRP to masonry bonded joint fastened by fiber nails . Specifically, the analysis of the displacement and the strain fields of the reinforced surface have been realized by means of Digital Image Correlation (DIC), an optical appealing method never used to study a FRP to support bonded joint fastened by FRP anchor.
The experimental analyses shown that the CFRP anchors applied onto a CFRP to support bonded joint permit to achieve two main advantages:
1) The increase of the maximal load peak
2) The attribution of a resistance post peak, and therefore, the increase of the ductility of the reinforced system.
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Ximenes, Francisco Xavier. "Durability of fibre reinforced polymer (FRP) composite pipe." Master's thesis, 2017. https://repositorio-aberto.up.pt/handle/10216/105726.
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Ximenes, Francisco Xavier. "Durability of fibre reinforced polymer (FRP) composite pipe." Dissertação, 2017. https://repositorio-aberto.up.pt/handle/10216/105726.
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CHOWDHURY, ERSHAD. "BEHAVIOUR OF FIBRE REINFORCED POLYMER CONFINED REINFORCED CONCRETE COLUMNS UNDER FIRE CONDITION." Thesis, 2009. http://hdl.handle.net/1974/5360.
Full textAbstract:
In recent years, fibre reinforced polymer (FRP) materials have demonstrated enormous
potential as materials for repairing and retrofitting concrete bridges that have deteriorated from factors such as electro-chemical corrosion and increased load requirements. However, concerns associated with fire remain an obstacle to applications of FRP materials in buildings and parking
garages due to FRP’s sensitivity to high temperatures as compared with other structural materials
and to limited knowledge on their thermal and mechanical behaviour in fire. This thesis presents
results from an ongoing study on the fire performance of FRP materials, fire insulation materials
and systems, and FRP wrapped reinforced concrete columns. The overall goal of the study is to
understand the fire behaviour of FRP materials and FRP strengthened concrete columns and
ultimately, provide rational fire safety design recommendations and guidelines for FRP
strengthened concrete columns.
A combined experimental and numerical investigation was conducted to achieve the
goals of this research study. The experimental work consisted of both small-scale FRP material
testing at elevated temperatures and full-scale fire tests on FRP strengthened columns. A
numerical model was developed to simulate the behaviour of unwrapped reinforced concrete and
FRP strengthened reinforced concrete square or rectangular columns in fire. After validating the
numerical model against test data available in literature, it was determined that the numerical
model can be used to analyze the behaviour of concrete axial compressive members in fire.
Results from this study also demonstrated that although FRP materials experience considerable
loss of their mechanical and bond properties at temperatures somewhat below the glass transition
temperature of the resin matrix, externally-bonded FRP can be used in strengthening concrete
structural members in buildings, if appropriate supplemental fire protection system is provided
over the FRP strengthening system.Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-12-17 14:11:27.931
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Lai, Yu Ching. "MOMENT CONNECTIONS OF CONCRETE-FILLED FIBRE REINFORCED POLYMER TUBES TO REINFORCED CONCRETE FOOTINGS." Thesis, 2010. http://hdl.handle.net/1974/5408.
Full textAbstract:
Fiber reinforced polymers (FRPs) are increasingly being accepted in structural engineering applications. One promising system involves the use of concrete-filled FRP tubes (CFFTs) as bridge piers, columns or piles. While CFFT members have been extensively studied under various loading conditions, very little attention has been given to their connections to other structural components such as footings and beams. This study explores two different moment connections for CFFT members, using 13 medium-scale specimens and seven ancillary tests.
The first connection involves embedment of the FRP tube into the concrete foundations during casting. Five-219 mm diameter (D) precast CFFTs were embedded into 500x500x500 mm concrete foundation each, at different embedment lengths ranging from 0.3D to 1.5D and tested in flexure as cantilevers with 1100 mm spans. The study showed that the optimal embedment length was 0.73D. This was essentially the minimum embedment length necessary to produce tension failure of the CFFT member outside the footing, rather than premature bond failure that would otherwise occur at lower loads. Additionally, six push-through tests were conducted on CFFT stubs embedded into footings. The average bond strength was found to be 0.75 MPa.
The second connection involved adhesive bonding of hollow FRP tubes to short reinforced concrete circular stubs protruding from concrete footings. The remainder of the tube was then filled with concrete, without the need for shoring. Four-169 mm diameter FRP tubes were first adhesively bonded onto footings with heavily steel-reinforced concrete stubs varying in length from 0.5D to 2.0D, and tested as cantilevers with 1300 mm spans. The optimal bond length that would lead to flexural failure of the tube just outside the stub, rather than bond failure, was about 1.1D. Based on this, two additional specimens with 1.5D stubs having varying steel reinforcement ratio (ρ) in the stubs were tested. It was shown that the optimal ρ was 2.5%. Finally, the effect of low cycle reversed bending fatigue was studied using two additional specimens, including one with a sustained axial load of 15-19% of the CFFT axial capacity. Remarkable levels of ductility associated with the plastic hinge forming in the stub were observed.Thesis (Master, Civil Engineering) -- Queen's University, 2010-01-28 16:09:40.606
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Kim, SJ. "Strengthening of RC slabs with penetrations using unanchored and anchored FRP composites." Thesis, 2009. http://hdl.handle.net/10453/30188.
Full textAbstract:
University of Technology, Sydney. Faculty of Engineering and Information Technology.Reinforced concrete (RC) slabs are one of the most commonly occurring structural forms. Penetrations (otherwise known as openings or cut-outs) in new as well as existing concrete slabs are commonly introduced due to structural and/or functional reasons. The introduction of a penetration, if large enough, may cause weakening of the slab which will then require the installation of strengthening. Traditional methods of strengthening RC slabs with penetrations, such as the addition of extra supports or bolted steel plates, can be expensive and cumbersome. Such traditional methods can however be replaced by the bonding of high strength, light-weight and durable fibre reinforced polymer (FRP) composites. In recent years, externally bonded FRPs have become popular as a means to strengthen or rehabilitate RC infrastructure, such as the flexural, shear or torsional strengthening as well as seismic retrofitting of beams, slabs, columns and connections. The effectiveness of the FRP strengthening may however be compromised by premature debonding failure of the FRP prior to its ultimate strength being reached. In order to optimise the use of FRP composites, such premature debonding failure should be prevented or delayed. To date, several different types of anchorage systems have in tum been introduced to FRP strengthened RC members, namely embedded metal threads, U-jackets, near surface mounted rods, and anchors made using FRP. FRP anchors are particularly attractive as they are non-corrosive and can be applied to slabs and walls. This dissertation is concerned with the strengthening of existing RC slabs with large penetrations with externally bonded FRP composites. FRP anchors are also researched and utilised in order to address the debonding issue. A review of the relevant literature is firstly given which justifies the need for the research presented herein. The remainder of the dissertation is then divided into four main sections, namely (i) pullout strength and behaviour of FRP anchor systems, (ii) shear strength and behaviour of FRP anchor systems, (iii) unanchored FRP-strengthened RC slabs with penetrations, (iv) FRP-strengthened RC slabs with penetrations with the addition of FRP anchors. In each of these four sections, experimental tests are reported. Overall, the slab strengthening schemes were found to be effective and the effectiveness of FRP anchor associated with the debonding issue was proved to be positive. Also reported in each of the four sections is the development of analytical models which have been derived from first principles and calibrated from the various Jest data. The results of parametric studies are then reported using the various analytical models and the influence of key geometrical and material properties identified. Design recommendations, which can be readily incorporated into existing design guidelines, are then given and future research needs are finally identified.
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Qasrawi, Yazan. "Flexural behaviour of spun-cast concrete-filled fibre reinforced polymer tubes for pole applications." Thesis, 2007. http://hdl.handle.net/1974/431.
Full textAbstract:
In this study, the feasibility of utilizing the spin casting technique with structural Fibre-Reinforced Polymer (FRP) tubes and eliminating steel reinforcement is explored for the first time. This would make spun-cast FRP tubes (SCFTs) desirable in pole applications, as they are relatively light-weight, protected from deicing salts and other elements by the tube, and have similar flexural resistance to the completely filled FRP tubes (CFFTs). This study evaluates the flexural and bond performances of SCFTs through experimental and analytical investigations. The experimental investigation included a total of nine beam specimens, approximately 330 mm in diameter and 2.85 m in length, tested in three and four-point bending. Glass-FRP (GFRP) tubes with different wall thicknesses and proportions of fibres in the longitudinal and hoop directions were used in eight specimens. One control specimen was cut from a conventional prestressed spun-cast pole and tested for comparison. Also, one specimen was essentially a control CFFT. The main parameters studied were tube laminate structure, concrete wall thickness, and the effect of additional steel rebar in SCFTs. The experimental investigation also included six push-off stub specimens tested to examine the bond behaviour of SCFTs. An analytical model predicting the flexural response of SCFT beams was developed, verified, and used in a parametric study to examine a wider range of tube laminate structures, concrete wall thicknesses and FRP tube thicknesses. The study demonstrated the feasibility of fabrication of SCFTs in conventional precast plants. SCFTs were shown to have similar flexural strength to conventional prestressed spun-cast poles of an equivalent reinforcement index but are less stiff due to the lower modulus of FRP and lack of prestressing. SCFTs with inner-to-outer diameter ratio (Di/Do) up to about 0.6 achieved the same flexural strength as the CFFT specimen. However, the parametric study showed that this optimum (Di/Do) ratio is dependent on tube thickness and laminate structure and is generally smaller in thicker tubes or tubes stiffer in the longitudinal direction.Thesis (Master, Civil Engineering) -- Queen's University, 2007-04-19 15:49:45.19
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Shier, GREGORY. "FLEXURAL BEHAVIOUR OF FIBRE REINFORCED POLYMER STRENGTHENED REINFORCED CONCRETE BEAMS AT ELEVATED TEMPERATURES." Thesis, 2013. http://hdl.handle.net/1974/7838.
Full textAbstract:
Fibre reinforced polymers (FRPs) have gained considerable popularity as a building and repair material. In particular, FRPs have been an economical means of extending the life of structures. As time passes, an increased number and variety of new and old structures are incorporating FRPs as reinforcement and for rehabilitation. Perhaps most common are their applications for bridge structures. Much of the reluctance towards the inclusion of FRP as primary reinforcement or as a rehabilitation measure in building structures is due to its poor performance in fires. In order to move forward with an understanding of how FRP may overcome its temperature-related short comings, it is important to explore the behaviour of FRP, and structures which utilize FRP for reinforcement, at elevated temperatures.
The results of a testing program including eleven high temperature, two room temperature intermediate-scale, FRP-strengthened, and one unstrengthened reinforced concrete beam tests are presented. The elevated temperature tests were conducted on both un-post-cured and post-cured FRP strengthening at temperatures up to 211°C. The tests also utilized a novel method for heating and post-curing FRP-strengthening in place. The strengthened beams exhibited strength gains above the unstrengthened reference beam, and it has been demonstrated that post-curing of an FRP system can be effective at increasing an FRP’s performance at elevated temperatures. Exposed to constant temperatures, un-post-cured specimens still exhibited substantial FRP strength at exposure temperatures up to Tg+79°C. Post-cured specimens exhibited similar performance at temperatures of Tg+43°C. The transient temperature tests resulted in
ii
beam failure at an average temperature of 186°C and 210°C for un-post-cured and post-cured FRP strengthening respectively at a constant applied load level 93% of that of the room temperature strengthened control beam. The results of this testing program demonstrate that FRP strengthening can remain effective when exposed to temperatures well above the measured value of Tg.Thesis (Master, Civil Engineering) -- Queen's University, 2013-02-28 15:14:31.336
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Tam, Sylvio Siu Fang. "Durability of fibre reinforced polymer (FRP) and FRP bond subjected to freeze-thaw cycles and sustained load." 2007. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=788860&T=F.
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Chaminda, Konthesingha Konthesingha Muhandiramlage. "Earthquake protection of masonry shear walls using fibre reinforced polymer strengthening." Thesis, 2012. http://hdl.handle.net/1959.13/935794.
Full textAbstract:
Research Doctorate - Doctor of Philosophy (PhD)Unreinforced masonry (URM) buildings are highly vulnerable to damage during earthquakes, due to their high mass, limited ductility and low tensile strength. However, being economical, durable, easy to procure and good for thermal and sound insulation ensures that URM is widely used both for low-rise structural walls and for infill to framed structures. In addition to that, many of the existing historically and culturally important buildings have been identified as URM constructions. Therefore, strengthening of URM buildings to resist earthquake damage has a remarkable importance. URM shear wall strengthening with near surface mounted (NSM) fibre reinforced polymer (FRP) strips is a relatively new and effective seismic retrofitting technique to improve their earthquake resistance. This technique involves inserting thin FRP strips into grooves cut into the surface of the wall. The aesthetic impact to the structure is minimal due to this strengthening technique compared with attaching FRP reinforcement to the surface of the wall (External Bonding (EB) technique). The other advantages of NSM FRP are the ability to develop higher strains in the FRP before debonding compared to EB techniques, and protection from vandalism, to some extent from fire and other environmental influences. In this research study an extensive experimental study along with numerical analyses were carried out to investigate the cyclic in-plane shear behaviour of unreinforced masonry (URM) walls retrofitted/strengthened with near surface mounted (NSM) fibre reinforced polymer (FRP) strips. Carbon FRP (CFRP) strips were used in this technique and were designed to enhance the performance of URM walls which fail by diagonal cracking or bed joint sliding within the height of the wall. The bond-slip behaviour between NSM FRP strips and clay brick masonry was investigated using six experimental pull tests under cyclic loading. The results including bond strengths, critical bond length and the local bond-slip behaviour were determined and were compared with a similar monotonically loaded pull test results. The bond-slip curves for monotonic and cyclic loading cases were approximately similar. Two major experimental investigations were carried out in this project to investigate the effectiveness of retrofitting/strengthening of URM walls panels with NSM CFRP strips using previously damaged and newly constructed undamaged wall panels. The effectiveness of NSM CFRP strip retrofitting applied to damaged URM walls was investigated using sixteen previously damaged wall panels with two different damage levels (lightly and highly) subjected to vertical pre-compression combined with increasing reversing cycles of in-plane lateral displacement. The damaged walls were partially repaired, retrofitted with NSM FRP strips and retested. The study assessed the effect on strength, displacement capacity, energy dissipation and ductility achieved by FRP retrofitting compared to the undamaged URM panels under different pre-compression levels. The retrofitted walls displayed higher displacement capacities compared with URM walls. The ultimate loads were not enhanced due to retrofitting under higher pre-compression levels. However the presence of the reinforcement restored the ultimate loads to those observed for the original undamaged URM state. The improvements in the behaviour of the URM walls due to retrofitting were generally similar irrespective of the amount of pre-existing damage in the URM walls. A new test setup representing realistic boundary conditions to simulate the earthquake behaviour of shear walls in actual buildings was designed and built for the series of experiments with newly constructed wall panels. It was designed to impose zero in-plane rotation (fixed-fixed) boundary conditions at the top and bottom of the masonry wall specimens. A representative finite element (FE) model was used to obtain the actual dimensions of the test setup. The design parameters for the experimental series, including test specimen dimensions and pre-compression loads to achieve diagonal cracking failure modes, were obtained using the same FE model. A total of twenty three wall panels constructed with two wall aspect ratios (height : length = 1 and 0.5) were tested. They were strengthened with NSM CFRP strips in six different reinforcement arrangements including vertical, horizontal and a combination of both. Four panels were tested under monotonically increasing in-plane lateral displacement and the others under increasing reversing cycles of in-plane lateral displacement combined with a vertical pre-compression. The expected zero in-plane rotation (fixed-fixed) boundary conditions were achieved from the new setup with classic diagonal failure occurring through the test walls. The displacement capacity, energy dissipation and ductility of the wall panels were enhanced due to the NSM FRP strengthening. The maximum load of the strengthened walls was increased compared to URM when the strengthening contained vertical FRP strips. The reinforcing scheme which used a combination of vertical and horizontal FRP strips performed the best. A finite element model was developed to validate the experimental results. The micro-modelling approach was used in this masonry model. The FRP strips were attached to the masonry model using the bond-slip relationship established from the experimental pull tests. The key behaviours of the experimental test results could be reproduced by the developed FE model.
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Cui, Ciyan. "Behaviour of Normal and High Strength Concrete Confined with Fibre Reinforced Polymers (FRP)." Thesis, 2009. http://hdl.handle.net/1807/17750.
Full textAbstract:
An extensive amount of research has been reported in previous literature on the behaviour of FRP-confined concrete subjected to concentric axial compression. However, data on the behaviour of high strength concrete confined with various types and configurations of FRP systems is still lacking and no consensus exists on the complete response of FRP-confined concrete. In addition, no appropriate design guidelines are currently available.
This thesis reports results from an experimental program involving 112 cylindrical concrete specimens, 88 of which were FRP-wrapped and the remaining 24 were control specimens. All the specimens were 152 mm in diameter and 305 mm in length. Test variables included: amount of FRP materials used, strength and stiffness of FRP materials, concrete strength, and the health of concrete at the time of strengthening.
Experimental results indicated that a pre-repair load of up to 77% of the unconfined concrete strength had no appreciable effect on the stress-strain response of FRP-confined concrete. With an increase of the unconfined concrete strength, the strength enhancement, energy absorption capacity, ductility factor and work (energy) index at rupture of FRP jackets all decreased remarkably. A positive correlation was found between confined concrete ductility and FRP rupture strain. In addition, a gradual post-peak failure of the specimens, observed previously from FRP-confined concrete columns tested at the University of Toronto, was also observed in some of the current tests -- owing to the high speed data acquisition system. That ductile failure can be attributed to the gradual unzipping failure of FRP jacket, which in turn is related to specimen size.
A new constitutive model was developed based on material properties, force equilibrium and strain compatibility. The size effect was taken into account in the model, which is able to accommodate concrete with a wide range of strength (25 MPa to 110 MPa) confined with various types and configurations FRP systems.
Design equations from CSA S806-02 and CSA S6-06 provide reasonable and conservative estimates for the FRP-confined concrete strength. To calculate the peak strain for FRP-confined concrete, an equation based on the work by Berthet et al. (2006) is proposed.
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Kara, Ilker F., and Ashraf F. Ashour. "Flexural performance of FRP reinforced concrete beams." 2012. http://hdl.handle.net/10454/7629.
Full textAbstract:
yesA numerical method for estimating the curvature, deflection and moment capacity of FRP reinforced concrete beams is developed. Force equilibrium and strain compatibility equations for a beam section divided into a number of segments are numerically solved due to the non-linear behaviour of concrete. The deflection is then obtained from the flexural rigidity at mid-span section using the deflection formula for various load cases. A proposed modification to the mid-span flexural rigidity is also introduced to account for the experimentally observed wide cracks over the intermediate support of continuous FRP reinforced concrete beams. Comparisons with experimental results show that the proposed numerical technique can accurately predict moment capacity, curvature and deflection of FRP reinforced concrete beams. The ACI-440.1R-06 equations reasonably predicted the moment capacity of FRP reinforced concrete beams but progressively underestimated the deflection of continuous ones. On the other hand, the proposed modified formula including a correction factor for the beam flexural rigidity reasonably predicted deflections of continuous FRP reinforced concrete beams. It was also shown that a large increase in FRP reinforcement slightly increases the moment capacity of FRP over-reinforced concrete beams but greatly reduces the defection after first cracking.
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Kara, Ilker F., and Ashraf F. Ashour. "Moment redistribution in continuous FRP reinforced concrete beams." 2013. http://hdl.handle.net/10454/7626.
Full textAbstract:
yesThe main purpose of this paper is to assess moment redistribution in continuous concrete beams reinforced with fibre reinforced polymer (FRP) bars. A numerical technique based on equilibrium of forces and full compatibility of strains has been developed to evaluate the moment–curvature relationships and moment capacities of FRP and steel reinforced concrete sections. Moment redistribution has then been assessed by comparing elastic and experimental moments at failure, and moment capacity at critical sections of continuous FRP reinforced concrete beams reported on the literature. The curvature of under reinforced FRP sections was large at FRP rupture but failure was sudden, that would not allow any moment redistribution. On the other hand, FRP over reinforced sections experienced higher curvature at failure than steel over reinforced sections owing to the lower FRP modulus of elasticity. Although the experimental and elastic bending moment distributions at failure are significantly different for many beams tested elsewhere, in particular CFRP reinforced concrete beams, the experimental bending moment over the middle support at failure was far lower than the corresponding moment capacity owing to the de-bonding of FRP bars from concrete in the middle support region. Furthermore, the hogging moment redistribution over the middle support is always larger than that at mid-span by around 66%. It was also shown that the load capacity prediction of continuous FRP reinforced concrete beams using the de-bonding moment at the middle support section was the closest to the experimental failure load.
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Almahakeri, MOHAMED. "STABILITY OF BURIED STEEL AND GLASS FIBRE REINFORCED POLYMER PIPES UNDER LATERAL GROUND MOVEMENT." Thesis, 2013. http://hdl.handle.net/1974/7888.
Full textAbstract:
As vast networks of high pressure buried energy pipelines traverse North America and other continents, the stability of such essential buried infrastructure must be maintained under a variety of earth loading conditions. The pipe-soil interaction and the longitudinal behaviour of buried pipes due to relative ground movements is poorly understood. This thesis presents full scale testing and numerical modeling of steel and Glass Fibre Reinforced Polymer (GFRP) pipelines to better understand the flexural performance of buried pipes subjected to lateral earth movement.
For the experimental phase of the study, a series of pipe bending experiments have been conducted on 102 mm nominal diameter and 1830 mm long steel and GFRP pipes buried in dense sand. Pipe loading was carried out by pulling pipe ends using two parallel cables attached to a spreader beam outside the test region, using a hydraulic actuator. The different tests covered burial depth-to-diameter (H/D) ratios of 3, 5 and 7. During the steel pipe testing phase, special consideration was given to assess the effect of boundary limits, friction within the pulling mechanism, and consistency of results using repeated tests. For the GFRP pipes, the experimental work investigated the effect of the laminate structure of the pipes, including both cross-ply and angle-ply laminates. Test results showed that burial depth significantly influenced the ultimate pulling forces, longitudinal strains, and pipe net deflection at mid-span. The results were also compared between the two types of pipes. The failure mechanism for all tests was consistently governed by soil failure, except for the angle-ply GFRP pipe that failed at a burial depth of H/D=7.
For the numerical analysis, the study presents the development and verification of two and three-dimensional numerical models including material constitutive models for both the pipe and for the soil using a stress-dependent modulus. Calculations are presented for different burial depths and are compared to experimental data. It was shown that the numerical model can successfully capture the pipe-soil interaction behaviour for both pipe types in terms of load-displacement responses and net bending deflection. Also, the effect of material variation and laminate structure were in agreement with test data.Thesis (Ph.D, Civil Engineering) -- Queen's University, 2013-04-18 22:21:53.025