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Farooq, Mohammed. "Development of FRP based composite fibre for fibre reinforced cementitious composites." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57668.
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This thesis describes a method of development of a novel fibre based on fibre reinforced polymers (FRP), for use fibre reinforcement in concrete. Thermosetting epoxy resin matrix were reinforced with E-glass, S-glass, and Carbon fibre to produce different types of composite fibres. The FRP panels were produced using the Vacuum Infusion technique, and then cut to different fibre sizes. The volume fractions of reinforcements within the FRP fibre were controlled by using woven and unidirectional fabrics. The number of layers of reinforcing fibres were also changed, to obtain the optimal thickness of the fibres. The FRP material was characterized by means of tensile tests and microscope image analysis. Four different compositions of FRP were produced with tensile strengths ranging from 195 MPa to 950 MPa. The different combinations in geometry broadened the total number of fibres investigated to 12. Single fibre pullout tests were performed to obtain the fundamental fibre-matrix interfacial bond parameters for the different FRP fibres. The FRP fibres, being hydrophilic, along with having a unique rough surface texture, showed a good bond with cement matrix. A bond strength superior to industrially available straight steel fibres and crimped polypropylene fibres has been observed. The 3 best fibres were then chosen to examine the flexural behaviour FRP fibre reinforced concrete beams. The optimized FRP fibres, one each of Glass FRP and Carbon FRP were then further investigated to study the effect of matrix maturity, temperature, fibre inclination, and loading rate on the fibre-matrix interfacial behaviour using single fibre pullout tests. Scanning Electron Microscope (SEM) analysis was carried out to identify the effect of above-mentioned factors on the surface characteristics of the fibre. An attempt was also made to optimize the fibre-matrix interface to achieve an optimized failure mechanism by coating the fibre with oil. The ability of the fibre to transfer stresses across a cracked section over extended periods has been investigated by means of fibre-relaxation tests. Finally, to assess durability, the fibres were conditioned at high pH and high temperature after which single fibre pullout, direct tension tests, & SEM analysis were conducted.<br>Applied Science, Faculty of<br>Civil Engineering, Department of<br>Graduate
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Senne, Jolyn Louise. "Fatigue Life of Hybrid FRP Composite Beams." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/33982.
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As fiber reinforced polymer (FRP) structures find application in highway bridge structures, methodologies for describing their long-term performance under service loading will be a necessity for designers. The designer of FRP bridge structures is faced with out-of-plane damage and delamination at ply interfaces. The damage most often occurs between hybrid plys and dominates the life time response of a thick section FRP structure. The focus of this work is on the performance of the 20.3 cm (8 in) pultruded, hybrid double web I-beam structural shape. Experimental four-point bend fatigue results indicate that overall stiffness reduction of the structure is controlled by the degradation of the tensile flange. The loss of stiffness in the tensile flange results in the redistribution of the stresses and strains, until the initiation of failure by delamination in the compression flange. These observations become the basis of the assumptions used to develop an analytical life prediction model. In the model, the tensile flange stiffness is reduced based on coupon test data, and is used to determine the overall strength reduction of the beam in accordance the residual strength life prediction methodology. Delamination initiation is based on the out-of-plane stress sz at the free edge. The stresses are calculated using two different approximations, the Primitive Delamination Model and the Minimization of Complementary Energy. The model successfully describes the onset of delamination prior to fiber failure and suggests that out-of-plane failure controls the life of the structure.<br>Master of Science
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Joyce, Peter James. "Experimental investigation of defect criticality in FRP laminate composites /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Feng, Zheng-Nong. "Thin FRP composite panels under high transverse pressure." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244978.
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Azzawi, Mostfa Al. "Investigations on FRP-Concrete Bond." Scholar Commons, 2018. http://scholarcommons.usf.edu/etd/7116.
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This dissertation presents findings from three separate investigations, a laboratory study and two field studies that evaluated the durability of the Fiber Reinforced Polymer (FRP)-concrete bond. The laboratory study explored the role of porosity on CFRP-concrete bond following immersion in warm water. Two disparate field studies measured residual bond after 20 years outdoor exposure of FRP repairs of full-size masonry walls and after 12 years for partially submerged piles supporting the Friendship Trail Bridge, Tampa Bay.
The ACI 440 code requires the same surface preparation for all externally bonded FRP concrete repairs. This disregards the role of porosity that is a function of the water / cementitious (w/c) ratio. Concretes with high w/c ratios are low strength concretes, have large voids and a more elaborate capillary pore network compared to low w/c, high strength concretes. Epoxies will therefore penetrate deeper into high porosity concretes. As a result, the performance of low strength, high porosity concrete under moisture exposure can be anticipated to be superior. The laboratory study was intended to determine whether this hypothesis was correct or not.
Three different concrete mixes with water / cementitious ratios of 0.73, 0.44 and 0.25 representing high, medium and low porosities were used for the study. The corresponding target compressive strengths were 2,500 psi, 5,000 psi and 7,500 psi respectively. A total of eighteen, 9 in. x 9 in. x 2.5 in. thick slabs, three for each concrete porosity were tested. Slabs were allowed to cure for over 90 days before surfaces were lightly sand blasted to provide the required concrete surface profile (CSP 3). Specimens were then pre-conditioned in an oven for 48 hours to ensure uniform drying.
Concrete porosity was characterized using mercury porosimetry, SEM, 3D surface scanning and images obtained using a portable microscope. Two commercially available CFRP materials were bonded to the oven-dried prepared slab surfaces and the epoxy allowed to cure at room temperature for 4 weeks. Twelve FRP bonded slabs were completely submerged in potable water at 30 oC (86 oF) as part of the aging program. The six remaining slabs were used for establishing baseline bond values through destructive pull-off tests. The twelve exposed slabs were similarly tested following 15 weeks of exposure.
Results showed minimal degradation in the high porosity, low strength concrete but over 20% reduction in the low porosity, higher strength concrete. Analysis of the failure plane indicated that the lower porosity of the high strength concrete had limited the depth to which the epoxy could penetrate. This was confirmed from magnified images of the bond line taken using a microscope and from a careful assessment of the failure mode. Findings also suggest that the CSP 3 surface profile (light sand blasting) may be adequate for lower strength concrete but not so for higher strength concrete. For applications where FRP concrete repairs of higher strength concrete are permanently or intermittently exposed to moisture, alternative surface preparation may be needed to allow epoxy to penetrate deeper into the concrete substrate. The viscosity of the resin hitherto not considered may be a critical parameter.
In 1995, two full-scale concrete masonry walls were repaired using three horizontally aligned 20 in. (508 mm) wide uni-directional carbon fiber sheets using different commercially available epoxies. Twenty years later the CFRP-CMU bond was determined through selective pull-off tests that were preceded by detailed non-destructive evaluation. Results showed that despite superficial damage to the top epoxy coating and debonding along masonry joints, the residual CFRP-CMU bond was largely unaffected by prolonged exposure to Florida’s harsh environment.
Therein, 99% of samples exhibited in cohesive failure of the CMU or mortar. Pull-off strength was poorer at mortar joints but because the CFRP was well bonded to the masonry surface, its impact on structural performance of the repair was expected to be minimal. Overall, the repairs proved to be durable with both epoxy systems performing well.
The Friendship Trail Bridge linking St. Petersburg to Tampa FL was demolished in 2016. This was the site of three disparate demonstration projects in which 13 corroding reinforced concrete piles were repaired using fiber reinforced polymer (FRP) in 2003-04, 2006, and 2008. The repairs were undertaken using combinations of carbon and glass fiber, pre-preg and wet layup, epoxy and polyurethane resin, and were installed using either shrink wrap or pressure bagging. Residual FRP-concrete bond was evaluated after up to 12 years of exposure through 120 pull-off tests conducted on 10 representative repaired piles. Results showed a wide variation in the measured pull-off strength depending on the type of resin, the number of FRP layers, the prevailing conditions at the time the epoxy was mixed and the method of installation. Epoxy-based systems were found to be sensitive to ambient conditions at installation. Pressure bagging improved performance. The highest residual bond was recorded in pressure bagged piles repaired in 2008. The findings suggest that in marine environments epoxy-based systems installed using pressure bagging can lead to durable repairs.
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Weaver, Craig Aaron. "Behavior of FRP-Reinforced Glulam-Concrete Composite Bridge Girders." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/WeaverCA2002.pdf.
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Bangalore, Gurudutt S. "Nondestructive evaluation of FRP composite members using infrared thermography." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2419.
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Thesis (M.S.)--West Virginia University, 2002.<br>Title from document title page. Document formatted into pages; contains viii, 101 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 98-101).
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Punyamurthula, Deepthi. "Structural performance of low-profile FRP composite celluar modules." Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3815.
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Thesis (M.S.)--West Virginia University, 2005<br>Title from document title page. Document formatted into pages; contains xi, 91 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 83-85).
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Deskovic, Nikola. "Innovative design of FRP composite members combined with concrete." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12687.
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Majumdar, Prasun Kanti. "Strength and Life Prediction of FRP Composite Bridge Deck." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/27285.
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Fiber reinforced polymer (FRP) composites are considered very promising for infrastructure applications such as repair, rehabilitation and replacement of deteriorated bridge decks. However, there is lack of proper understanding of the structural behavior of FRP decks. For example, due to the localization of load under a truck tire, the conventionally used uniform patch loading is not suitable for performance evaluation of FRP composite deck systems with cellular geometry and relatively low modulus (compared to concrete decks). In this current study, a simulated tire patch loading profile has been proposed for testing and analysis of FRP deck. The tire patch produced significantly different failure mode (local transverse failure under the tire patch) compared to the punching-shear mode obtained using the conventional rectangular steel plate. The local response of a cellular FRP composite deck has been analyzed using finite element simulation and results are compared with full scale laboratory experiment of bridge deck and structure. Parametric studies show that design criteria based on global deck displacement is inadequate for cellular FRP deck and local deformation behavior must be considered.
The adhesive bonding method is implemented for joining of bridge deck panels and response of structural joint analyzed experimentally. Strength, failure mode and fatigue life prediction methodologies for a cellular FRP bridge deck are presented in this dissertation.<br>Ph. D.
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Schniepp, Timothy John. "Design Manual Development for a Hybrid, FRP Double-Web Beam and Characterization of Shear Stiffness in FRP Composite Beams." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34550.
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Fiber-reinforced polymeric (FRP) composites are being considered for structural members in bridge construction as lighter, more durable alternatives to steel and concrete. Extensive testing and analysis of a pultruded, hybrid double web beam (DWB) developed for use in bridge construction has been conducted at Virginia Tech. A primary purpose of this testing is the development of a structural design guide for the DWB, which includes stiffness and strength data. The design manual also includes design allowables determined through a statistical analysis of test data.
Static testing of the beams, including failure tests, has been conducted in order to determine such beam properties as bending modulus, shear stiffness, failure mode, and ultimate capacity. Measuring and calculating the shear stiffness has proven to be an area of particular interest and difficulty. Shear stiffness is calculated using Timoshenko beam theory which combines the shear stiffness and shear area together along with a shear correction factor, k, which accounts for the nonuniform distribution of shear stress/strain through the cross-section of a structure. There are several methods for determining shear stiffness, kGA, in the laboratory, including a direct method and a multi-span slope method. Herein lays the difficulty as it has been found that varying methods produces significantly different results. One of the objectives of current research is to determine reasons for the differences in results, to identify which method is most accurate in determining kGA, and also to examine other parameters affecting the determination of kGA that may further aid the understanding of this property.
This document will outline the development of the design guide, the philosophy for the selection of allowables and review and discuss the challenges of interpreting laboratory data to develop a complete understanding of shear effects in large FRP structural members.<br>Master of Science
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Simon, Pavel. "Progresivní styčníky FRP kompozitů konstrukcí dopravní infrastruktury." Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-390279.
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This thesis deals with junction points of construction used in transport infrastructure, which are made of FRP composite material. Main focus is on bonded joints. The material and geometrical criteria od FRP material and there influence to junctions are analyzed. In sequential steps the development of the design of joints applicable to reference constructions - pedestrian walkways is documented. There are also presented practical experiences from the tests of joints of overlapped and single-sided joints, as well as experience from the design, production and testing of two types of pedestrian bridges on a real scale. Furthermore, extensive comparison of joints, in particular T-joints with closed profiles for selected types of fasteners, is provided. From a simple connection, screws and rivets or plain bonding to combined joints. These are assessed both in terms of bearing capacity and their deformation behavior. These tests are performed for two material combinations, FRP-FRP and FRP-steel.
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Luk, Herman Chi Yung. "FRP-strengthened beam : interfacial failure and development of empirical design approach /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202002%20LUK.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.<br>Includes bibliographical references (leaves 216-222). Also available in electronic version. Access restricted to campus users.
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Tsang, Terry Kin Chung. "Behaviour of concrete beams reinforced with hybrid FRP composite rebars /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202006%20TSANGT.
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Photiou, Nikolaos K. "Rehabilitation of steel members utilising hybrid FRP composite material systems." Thesis, University of Surrey, 2005. http://epubs.surrey.ac.uk/634/.
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Botting, Joshua Keith. "Development of an FRP Reinforced Hardwood Glulam Guardrail." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/BottingJK2003.pdf.
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Shanmugam, Jayasiri. "Moment capacity and deflection behaviour of pultruded FRP composite sheet piles." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81565.
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The structural behaviour of FRP-composite (E-glass/polyester) sheet pile panels subjected to uniform pressure load was investigated. Single, connected and concrete-filled 2.13 m panels were tested to failure with the objective of determining their moment capacity and failure mechanism. As the uniform load test procedure utilized in this study allowed for the prevention of premature local crushing behaviour within the span, the average moment capacity obtained in this study was more than double that found in prior studies of FRP sheet pile panels, averaging 11.15 kN.m in single panel tests and 9.32 kN.m in connected panel tests. Single panels exhibited little difference in moment capacity whether tested in the upright or inverted orientation and there was no apparent reduction in capacity when a single panel was subjected to repeated load cycles. Failure of both single and connected panels was generally attributable to local buckling and invariably occurred at a deflection of about 50mm, indicating that deflection limits may govern design. No joint failure was observed in connected panels. (Abstract shortened by UMI.)
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Huang, Chia-Yen. "Preliminary study on embedded vasculatures in self-healing FRP composite laminates." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535652.
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Bradford, Nicholas M. "Design Optimization of Frp Composite Panel Building Systems: Emergency Shelter Applications." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000484.
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Maneepan, Komsan. "Genetic algorithm based optimisation of FRP composite plates in ship structures." Thesis, University of Southampton, 2007. https://eprints.soton.ac.uk/52012/.
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Composite materials (herein means Fibre Reinforced Plastic, FRP) are increasingly usedin the construction of marine vehicles because of their outstanding strength, stiffness and light weight properties. However, the use of FRP comes with difficulties in the design process as a result of the large number of design variables involved: composite material design, topologies and laminate schemes. All variables are related to each other leading to a high dimensional and flexible design space. It is hard to use traditional design methods in order to gain solutions for an initial design stage in a short time. Hence, this thesis deals with the presentation of a structural synthesis (optimisation framework) for plate components of composite ship structures. The framework broadly consists of an optimisation technique and structural analytical methods. To make the framework compatible with the nature of composite ship structural design problems, the Genetic Algorithm (GA) is selected as the optimisation tool because of its robustness, its ability in dealing with both continuous and discrete variables and its excellent searching for a global optimum. The typical plate types in a ship structure are the stiffened and unstiffened plates. For a stiffened plate, the combination of the grillage analysis of energy method based on Navier solution and an equivalent elastic properties approach are introduced. Using this, it is possible to produce layer by layer optimisation results for the base plate, web and crown of the stiffened plate. Unfortunately, solutions of the adopted grillage analysis do not cover the mechanical behaviour of the plate between stiffeners so the Higher-Order Shear Deformation Theory (HSDT) must be employed. This method provides accurate solutions for thin to moderately thick plates with a compromised computational time. Then stiffness, strength and stability can be considered in the design problem. In addition, to achieve the program of the structural synthesis, various computational modules are implemented according to the evaluation of composite micromechanics properties, maximum stress failure criteria and structural weight function. Then the main modules are validated with available resources. The usefulness of the program has been proved by comparing it with the optimal solutions from finite element software. Finally, many application examples of secondary and tertiary composite ship structures are presented. The optimal results prove the success of the optimisation framework. This could be evidence for further improvement to obtain a valuable structural optimisation tool.
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Na, Gwang-Seok. "Load-displacement behavior of frame structures composed of fiber reinforced polymeric composite materials." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26699.
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Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Dr. Leroy Z. Emkin; Committee Co-Chair: Dr. Abdul-Hamid Zureick; Committee Member: Dr. Dewey H. Hodges; Committee Member: Dr. Kenneth M. Will; Committee Member: Dr. Rami M. Haj-ali. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Hong, Yong. "Fatigue and Fracture of the FRP-Wood Interface: Experimental Characterization and Performance Limits." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/HongY2003.pdf.
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Lau, Tak-bun Denvid. "Flexural ductility improvement of FRP-reinforced concrete members." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38907756.
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Van, Nosdall Stephen Paul. "Experiments on a Hybrid Composite Beam for Bridge Applications." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23106.
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This thesis details a study of the structural behavior of Hybrid-Composite Beams (HCB) consisting of a fiber reinforced polymer (FRP) shell with a concrete arch tied with steel prestressing strands. The HCB offers advantages in life cycle costs through reduced transportation weight and increased corrosion resistance. By better understanding the system behavior, the proportion of load in each component can be determined, and each component can be designed for the appropriate forces. A long term outcome of this research will be a general structural analysis framework that can be used by DOTs to design HCBs as rapidly constructible bridge components. This study focuses on identifying the load paths and load sharing between the arch and FRP shell. <br />Testing was performed by applying point loads on simple span beams (before placing the bridge deck) and a three beam skewed composite bridge system. Curvature from strain data is used to find internal bending forces, and the proportion of load within the arch is found. Additionally, a stress integration method is used to confirm the internal force contributions. The tied arch carries about 80% of the total load for the non-composite case without a bridge deck. When composite with a bridge deck, the arch has a minimal contribution to the HCB stiffness and strength as it is below the neutral axis. For this composite case the FRP shell and prestressing strands resist about 85% of the applied load while the bridge deck carries the remaining 15% to the end diaphragms and bearings.<br /><br>Master of Science
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Herzog, Benjamin J. "Characterization of the Void Content of Fiber Reinforced Polymer (FRP) Composite Materials Fabricated by the Composites Pressure Resin Infusion System (COMPRIS)." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/HerzogBJ2004.pdf.
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Vasiliu, Andrei. "Masonry columns confined by composite materials: Experimental investigation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7359/.
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This study wants to analyze the effectiveness of different reinforcement typologies for masonry columns, in particular Fiber-Reinforced Polymer (FRP) and FRCM. The behavior of 10 solid – brick columns that are externally wrapped by FRP sheets and 2 unreinforced columns are presented in this study. The specimens are subjected to axial load until failure occurs. Three different confinement schemes were experimentally analyzed in order to evaluate and compare the effectiveness of the proposed strengthening techniques: 1) Grid carbon FRP (CFRP_G); 2) Grid glass FRP (GFRP_G); 3) Uniaxial carbon FRP (CFRP_U). Two different configurations of the reinforcing system were investigated: FRP sheets are applied as external reinforcement along the perimeter of the masonry columns in the form of continuous and discontinuous wrap, respectively. The results, compared with those for un-reinforced columns, indicate an increases in ultimate load, stiffness and ductility.
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Lau, Tak-bun Denvid, and 劉特斌. "Flexural ductility improvement of FRP-reinforced concrete members." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38907756.
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Ramroth, William T. "Thermo-mechanical structural modelling of FRP composite sandwich panels exposed to fire." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3232967.
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Thesis (Ph. D.)--University of California, San Diego, 2006.<br>Title from first page of PDF file (viewed December 1, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 155-161).
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Ge, W., K. Chen, Z. Guan, Ashraf F. Ashour, W. Lu, and D. Cao. "Eccentric compression behaviour of concrete columns reinforced with steel-FRP composite bars." Elsevier, 2021. http://hdl.handle.net/10454/18412.
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Yes<br>Eccentric compression behaviour of reinforced concrete (RC) columns reinforced by steel-FRP composite bars
(SFCBs) was investigated through experimental work and theoretical analyses. The tension and compression test results
show that SFCBs demonstrate a stable post-yield stiffness. The mechanical properties of the composite reinforcement
have a significant influence on eccentric compression behaviour of the reinforced concrete columns, in terms of failure
mode, crack width, deformation and bearing capacity. Formulae were also developed to discriminate failure mode and to
determine moment magnification factor, bearing capacity and crack width of the columns studied, with the theoretical
predictions being in a good agreement with the experimental results. In addition, parametric studies were conducted to
evaluate the effects of mechanical properties of reinforcement, reinforcement ratio, eccentricity, slenderness ratio, types of
reinforcement and concrete on the eccentric compression behaviour of RC columns. The results show that the
compressive performance is significantly improved by using the high performance concrete, i.e. reactive powder concrete
(RPC) and engineered cementious composites (ECC).<br>financial supports of the work by the National Natural Science Foundation of China (51678514), the Natural Science Foundation of Jiangsu Province, China (BK20201436), the China Postdoctoral Science Foundation (2018M642335), the Science and Technology Project of Jiangsu Construction System (2018ZD047), the Deputy General Manager Science and Technology Project of Jiangsu Province (FZ20200869), the Cooperative Education Project of Ministry of Education, China (201901273053), the Blue Project Youth Academic Leader of Colleges and Universities in Jiangsu Province (2020), the Six Talent Peaks Project of Jiangsu Province (JZ-038, 2016), the Yangzhou University Top Talents Support Project and the Jiangsu Government Scholarship for Overseas Studies.<br>The full-text of this article will be released for public view at the end of the publisher embargo on 3 Apr 2022.
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Richie, Matthew. "Fatigue Behavior of FRP-Reinforced Douglas-Fir Glued Laminated Bridge Girders." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/RichieMC2003.pdf.
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Gamache, Christopher P. "Preliminary Investigation on the Durability of FRP Reinforced Glulam Bridge Girders." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/GamacheCP2001.pdf.
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Kalhor, Roozbeh. "Energy Absorption of Metal-FRP Hybrid Square Tubes." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/74960.
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Lower-cost manufacturing methods have increased the anticipation for economical mass production of vehicles manufactured from composite materials. One of the potential applications of composite materials in vehicles is in energy-absorbing components such as hollow shells and struts (these components may be in the form of circular cylindrical shells, square and rectangular tubes, conical shells, and frusta). However, constructions which result in brittle fracture of the composite tubes in the form of circumferential or longitudinal corner crack propagation may lead to unstable collapse failure mode and concomitant very low energy absorption. As a result, metal-composite hollow tubes have been developed that combine the benefits of stable ductile collapse of the metal (which can absorb crushing energy in a controlled manner) and the high strength-to-weight ratio of the composites. The relative and absolute thicknesses of metal or FRP section has a substantial effect on energy absorption of the hybrid tubes. In particular, likelihood of delamination occurrence raises with increase in FRP thickness. This can reduce the energy absorption capability of the metal-FRP hybrid tubes. Additionally, adding a very thick FRP section may result in a global buckling failure mode (rather than local folding). Until now, there are no studies specifically addressing the effect of FRP thickness on energy absorption of hybrid tubes. In this study, the effects of fiber orientation and FRP thickness (the number of layers) on the energy absorption of S2-glass/epoxy-304 stainless steel square tubes were experimentally investigated. In addition, a new geometrical trigger was demonstrated which has positive effects on the collapse modes, delamination in the FRP, and the crush load efficiency of the hybrid tube.
To complete this study, a new methodology including the combination of experimental results, numerical modeling, and a multi-objective optimization process was introduced to obtain the best combination of design variables for hybrid metal-composite tubes for crashworthiness applications. The experimental results for the S2 glass/epoxy-304 stainless steel square tubes with different configurations tested under quasi-static compression loading were used to validate numerical models implemented in LS-DYNA software. The models were able to capture progressive failure mechanisms of the hybrid tubes. In addition, the effects of the design variables on the energy absorption and failure modes of the hybrid tubes were explained. Subsequently, the results from the numerical models were used to obtain optimum crashworthiness functions. The load efficiency factor (the ratio of mean crushing load to maximum load) and ratio between the difference of mean crushing load of hybrid and metal tube and thickness of the FRP section were introduced as objective functions. To connect the variables and the functions, back-propagation artificial neural networks (ANN) were used. The Non-dominated Sorting Genetic Algorithm–II (NSGAII) was applied to the constructed ANNs to obtain optimal results. The results were presented in the form of Pareto frontiers to help designers choose optimized configurations based on their manufacturing limitations. Such restrictions may include, but are not limited to, cost (related to the number of layers), laminate architecture (fiber orientation and stacking sequence) which can be constrained by the manufacturing techniques (i.e. filament winding) and thickness (as an example of physical constraints).<br>Ph. D.
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Chen, Yi 1975. "Local buckling behaviour of pultruded FRP composite sheet piles subjected to uniform pressure." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98950.
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The buckling behaviour of fibre reinforced polymer (FRP) sheet pile panels subjected to a uniform lateral pressure was investigated. Based on the previous full scale tests by Shanmugan in year 2003 (Shanmugan, 2004), the critical load at buckling initiation was first determined through experimental data analysis, and the theoretical modeling was then followed in an attempt to predict the buckling initiation and understanding the failure mechanism. The behavior of the panels loaded in upright position and inverted position was studied.<br>The local buckling of the compressive flanges was monitored by the strain measurements, which demonstrated that when tested in upright position, the panel failed immediately after local buckling of compressive flange, and when tested in inverted position, the panels could be able to carry the load into post buckling region. The stresses and corresponding axial forces at buckling were calculated by the classical beam flexure formula but taking into consideration the reduction of flexure rigidity and neutral axis shifting. The axial force calculated from the beam flexure formula was comparable with that from stain gauge measurements. The axial force was not uniformly distributed along the width of the compressive flange at upright position and was about zero at the free edge. When tested in inverted position, the neutral axis distance and the flexure rigidity kept almost as a constant. The sheet pile panels were with a uniform axial force along the width of the compressive flange.<br>An analytical modeling was performed to predict the buckling initiation. The buckling of the panel was simplified as the buckling of the compressive flange with various boundary conditions. The differential equation of the compressive flange was established based on the assumption that the flange was subjected to an in-plane axial force and an out-of-plane lateral pressure simultaneously. It was found that the lateral pressure did not have direct effect on the critical load. It was the compressive axial force that determined the local buckling of the flange. Kollar's explicit expressions were also applied but only valid for long plate loaded by uniform axial force.<br>The buckling load obtained by solving the differential equation for the inverted panel compared well with that from the experimental results. However, for the flange in a pile at an upright position, the theoretical prediction was far less than the experimental value which might be attributed to the non uniform axial force on the flange. Energy method was applied to estimate the range of the buckling load of a plate loaded by a linearly distributed axial force. The upper bound value was obtained from fixed boundary condition and the lower bound from simply supported assumption. The experimental result was found in between the two bounds and was in favour of the lower bound as a conservative estimation of critical load for upright panel.
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Dutta, Shasanka Shekhar. "Nondestructive and destructive evaluation of FRP composite wrapped concrete cylinders with embedded debonds." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/10966.
Full textAbstract:
Thesis (Ph. D.)--West Virginia University, 2010.<br>Title from document title page. Document formatted into pages; contains xxiii, 184 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 134-138).
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O'Neill, Kevin. "FEASIBILITY STUDY OF LIGHTWEIGHT HIGH-STRENGTH HOLLOW CORE BALSA-FRP COMPOSITE BEAMS UNDER FLEXURE." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3109.
Full textAbstract:
The United States of America s Military, more specifically the Army, has since the late 1990 s had a vested interest in the development of super-lightweight, portable, short-span composite bridge and decking components to replace aging heavy metal-alloy machine driven modular systems. The following study looks at the feasibility of using balsa wood as the structural core material in fiber reinforced polymer (FRP) wrapped hollow-core composites in short-span bridge applications. The balsa provides shear resistance and the FRP the flexural resistance, resulting in extremely high strength-to-weight and strength-to-depth ratios. Several scaled short span specimens were constructed and tested using a variety of fibers and resins. In addition, a calibrated finite element model (FEM) was developed using data acquired through testing. Of the 3 FRP-matrices tested (carbon-polyurethane, glass-polyurethane, and carbon-epoxy-resin), the carbon-epoxy-resin had the stiffest cross-section and highest ultimate load achieved, although the fiber did not have the highest elastic modulus and ultimate rupture strength of the constituent materials. The carbon-polyurethane fiber had the largest elastic modulus and ultimate strength, but due to construction difficulties did not perform as well as expected. The glass-polyurethane fiber had the lowest elastic modulus and ultimate load with high strain values and performed accordingly during specimen testing. Given the constraints of self-weight, section geometry, and deflection set forth for lightweight short-span portable bridging solutions, this study demonstrates that the balsa-FRP composite systems are viable solutions; in particular, when carbon fabric is paired with balsa cores.<br>M.S.C.E.<br>Department of Civil and Environmental Engineering<br>Engineering and Computer Science<br>Civil Engineering MS
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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/.
Full textAbstract:
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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Zhou, Aixi. "Stiffness and Strength of Fiber Reinforced Polymer Composite Bridge Deck Systems." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/29210.
Full textAbstract:
This research investigates two principal characteristics that are of primary importance in Fiber Reinforced Polymer (FRP) bridge deck applications: STIFFNESS and STRENGTH. The research was undertaken by investigating the stiffness and strength characteristics of the multi-cellular FRP bridge deck systems consisting of pultruded FRP shapes.
A systematic analysis procedure was developed for the stiffness analysis of multi-cellular FRP deck systems. This procedure uses the Method of Elastic Equivalence to model the cellular deck as an equivalent orthotropic plate. The procedure provides a practical method to predict the equivalent orthotropic plate properties of cellular FRP decks. Analytical solutions for the bending analysis of single span decks were developed using classical laminated plate theory. The analysis procedures can be extended to analyze continuous FRP decks. It can also be further developed using higher order plate theories.
Several failure modes of the cellular FRP deck systems were recorded and analyzed through laboratory and field tests and Finite Element Analysis (FEA). Two schemes of loading patches were used in the laboratory test: a steel patch made according to the ASSHTO's bridge testing specifications; and a tire patch made from a real truck tire reinforced with silicon rubber. The tire patch was specially designed to simulate service loading conditions by modifying real contact loading from a tire. Our research shows that the effects of the stiffness and contact conditions of loading patches are significant in the stiffness and strength testing of FRP decks. Due to the localization of load, a simulated tire patch yields larger deflection than the steel patch under the same loading level. The tire patch produces significantly different failure compared to the steel patch: a local bending mode with less damage for the tire patch; and a local punching-shear mode for the steel patch. A deck failure function method is proposed for predicting the failure of FRP decks. Using developed laminated composite theories and FEA techniques, a strength analysis procedure containing ply-level information was proposed and detailed for FRP deck systems. The behavior of the deck's unsupported (free) edges was also investigated using ply-level FEA.<br>Ph. D.
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Pando, Miguel A. "A Laboratory and Field Study of Composite Piles for Bridge Substructures." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/26314.
Full textAbstract:
Typically, foundation piles are made of materials such as steel, concrete, and timber. Problems associated with use of these traditional pile materials in harsh marine environments include steel corrosion, concrete deterioration, and marine borer attack on timber piles. It has been estimated that the U.S. spends over $1 billion annually in repair and replacement of waterfront piling systems. Such high repair and replacement costs have led several North American highway agencies and researchers to investigate the feasibility of using composite piles for load bearing applications, such as bridge substructures. As used here, the term â composite pilesâ refers to alternative pile types composed of fiber reinforced polymers (FRPs), recycled plastics, or hybrid materials. Composite piles may exhibit longer service lives and improved durability in harsh marine environments, thereby presenting the potential for substantially reduced total costs. Composite piles have been available in the North American market since the late 1980â s, but have not yet gained wide acceptance in civil engineering practice. Potential disadvantages of composite piles are high initial cost and questions about engineering performance. At present, the initial cost of composite piles is generally greater than the initial cost of traditional piles. Performance questions relate to driving efficiency, axial stiffness, bending stiffness, durability, and surface friction. These questions exist because there is not a long-term track record of composite pile use and there is a scarcity of well-documented field tests on composite piles.
This research project was undertaken to investigate the engineering performance of composite piles as load-bearing foundation elements, specifically in bridge support applications. The objectives of this research are to: (1) evaluate the soil-pile interface behavior of five composite piles and two conventional piles, (2) evaluate the long-term durability of concrete-filled FRP composite piles, (3) evaluate the driveability and the axial and lateral load behavior of concrete-filled FRP composite piles, steel-reinforced recycled plastic composite piles, and prestressed concrete piles through field tests and analyses, and (4) design and implement a long-term monitoring program for composite and conventional prestressed concrete piles supporting a bridge at the Route 351 crossing of the Hampton River in Virginia. A summary of the main findings corresponding to each of these objectives is provided below.
A laboratory program of interface testing was performed using two types of sands and seven pile surfaces (five composite piles and two conventional piles). The interface behavior of the different pile surfaces was studied within a geotribology framework that investigated the influence of surface topography, interface hardness, and particle size and shape. In general, the interface friction angles, both peak and residual, were found to increase with increasing relative asperity height and decreasing relative asperity spacing. The interface shear tests for the three pile types tested at the Route 351 bridge showed that, for medium dense, subrounded to rounded sand, with a mean particle size of 0.5 mm, the residual interface friction angles are 27.3, 24.9, and 27.7 degrees for the FRP composite pile, the recycled plastic pile, and the prestressed concrete pile, respectively. Interface shear tests on these same piles using a medium dense, subangular to angular sand, with a mean particle size of 0.18 mm, resulted in residual interface friction angles of 29.3, 28.8, and 28.0 degrees for the FRP composite pile, the recycled plastic pile, and the prestressed concrete pile, respectively.
A laboratory durability study was completed for the FRP shells of concrete-filled FRP composite piles. Moisture absorption at room temperature caused strength and stiffness degradations of up to 25% in the FRP tubes. Exposure to freeze-thaw cycles was found to have little effect on the longitudinal tensile properties of saturated FRP tubes.
Analyses were performed to investigate the impact of degradation of the FRP mechanical properties on the long-term structural capacity of concrete-filled FRP composite piles in compression and bending. The impact was found to be small for the axial pile capacity due to the fact that the majority of the capacity contribution is from the concrete infill. The impact of FRP degradation was found to be more significant for the flexural capacity because the FRP shell provides most of the capacity contribution on the tension side of the pile.
Full-scale field performance data was obtained for two composite pile types (concretefilled FRP composite piling and steel-reinforced recycled plastic piling), as well as for conventional prestressed concrete piles, by means of load test programs performed at two bridge construction sites: the Route 351 bridge and the Route 40 bridge crossing the Nottoway River in Virginia. The field testing at the two bridges showed no major differences in driving behavior between the composite piles and conventional prestressed concrete piles. Pile axial capacities of the composite piles tested at the Route 351 bridge were between 70 to 75% of the axial capacity of the prestressed concrete test pile. The FRP and prestressed concrete piles exhibited similar axial and lateral stiffness, while the steel-reinforced plastic pile was not as stiff. Conventional geotechnical analysis procedures were used to predict axial pile capacity, axial load-settlement behavior, and lateral load behavior of the piles tested at the Route 351 bridge. The conventional analysis procedures were found to provide reasonable predictions for the composite piles, or at least to levels of accuracy similar to analyses for the prestressed concrete pile. However, additional case histories are recommended to corroborate and extend this conclusion to other composite pile types and to different soil conditions.
A long-term monitoring program for composite and conventional prestressed concrete piles supporting the Route 351 bridge was designed and implemented. The bridge is still under construction at the time of this report, therefore no conclusions have been drawn regarding the long-term performance of concrete-filled FRP composite piles. The longterm monitoring will be done by the Virginia Department of Transportation.
In addition to the above findings, initial cost data for the composite piles and prestressed concrete piles used in this research were compiled. This data may be useful to assess the economic competitiveness of composite piles. The initial unit cost of the installed composite piles at the Route 40 bridge were about 77 % higher than the initial unit cost for the prestressed concrete piles. The initial unit costs for the composite piles installed at the Route 351 bridge were higher than the initial unit cost of the prestressed concrete piles by about 289% and 337% for the plastic and FRP piles, respectively. The cost effectiveness of composite piles is expected to improve with economies of scale as production volumes increase, and by considering the life-cycle costs of low-maintenance composite piles.<br>Ph. D.
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Lagiň, Juraj. "Řešení vybraných detailů betonových konstrukcí s využitím FRP výztuže." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409796.
Full textAbstract:
The diploma thesis is devided into two levels. The Primary part of the thesis is the theoretical part, which is part of project „FV10588 – New generation of spatial prefab made from high-firm concrete with increased mechanical resistence and endurance“, realized in cooperation with Faculty of Civil Engineering at VUT university – Institute of concrete and masonry structures. The project deals with frame corners in the form of steel and composite reinforcement which will compared through experiments and various kind of calculate proceedings. The secondary part of thesis focuses on the static-design project of cooling reservoir, placed under the ground, while is stressed by temperature. The reinforcement of the construction is realized in two ways – steel and composite reinforcement with their effectivity compared.
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Cain, Jason James. "Long Term Durability of Glass Reinforced Composites." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26973.
Full textAbstract:
This dissertation discusses topics related to the performance and long-term durability of glass-reinforced composites.
The first portion of this dissertation describes work to assess the effect that post-curing has on widely used E-glass/vinyl-ester composites (E-glass/Derakane 510-A and E-glass/Derakane 8084). It is shown that post-curing can have significant positive effects on the initial material properties of glass-reinforced vinyl ester composites. Furthermore, the post-cure of 82ºC for four hours stabilizes the matrix, and as such reduces matrix-related material property evolution. By stopping or nearly stopping material property evolution due to matrix curing over time, the post-cure regime isolates and allows the study of other time-dependent effects, such as fatigue or hygrothermal degradation, and aids designers by establishing an unchanging base set of initial (undamaged) material design properties.
The second portion of this dissertation discusses the effects that mean stress and R-ratio have on the fatigue performance of the same material. Qualitative and quantitative differences are seen in the performance as a function of the loading ratio. A residual strength based life prediction model developed at Virginia Tech is applied to the fatigue data, characterizing the material under constant-amplitude loading. Three curve-fitting parameters are then used along with the model to predict variable-amplitude fatigue lives, with remarkably good results.
The final portion of the dissertation concerns the effect of hygrothermal and accelerated aging on glass-reinforced composites. A meta-study is performed on data from the literature, and a glass-degradation-based life-prediction model is applied to the data. It is seen that a static fatigue-based activation energy approach to residual strength can predict activation energies associated with glass-reinforced composite strength degradation in the case of glass-reinforced concrete quite well, predicting values of 80-100 kJ/mol, which are similar to those expected for glass dissolution via silica ring opening. The model may also hold some promise for doing the same for glass-reinforced polymer composites.<br>Ph. D.
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Liu, Zihong. "Testing and Analysis of a Fiber-Reinforced Polymer (FRP) Bridge Deck." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/28234.
Full textAbstract:
A fiber reinforced polymer (FRP) composite cellular deck system was used to rehabilitate a historical cast iron thru-truss structure (Hawthorne St. Bridge in Covington, Virginia). This research seeks to address following technical needs and questions to advance FRP deck application.
The critical panel-to-panel connections were developed and evolved through a four-stage study and finally realized using full width, adhesively bonded tongue and groove splices with scarfed edges. Extensive experimental study under service, strength and fatigue loads in a full-scale two-bay mock-up test and a field test was performed. Test results showed that no crack initiated in the joints under service load and no significant change in stiffness or strength of the joint occurred after 3,000,000 cycles of fatigue loading. Various issues related to constructability of FRP deck systems were investigated and construction guidelines and installation procedures for the deck system were established.
The structural performance of the FRP-on-steel-superstructure system was examined in the laboratory and field under service load. Tests results confirmed the following findings: (1) the clip-type of panel-to-stringer connection provides little composite action as expected, which fulfilled the design intention; (2) local effects play an important role in the performance of FRP deck; (3) the FRP deck design is stiffness driven rather than strength driven like traditional concrete deck.
Finally, an FEM parametric study was conducted to examine two important design issues concerning the FRP decks, namely deck relative deflection and LDF of supporting steel girders. Results from both FEM and experiments show that the strip method specified in AASHTO LRFD specification (AASHTO 2004) as an approximate method of analysis can also be applied to unconventional FRP decks as a practical method. However, different strip width equations have to be determined by either FEM or experimental methods for different types of FRP decks. In this study, one such an equation has been derived for the Strongwell deck. In addition, the AASHTO LDF equations for glued laminated timber decks on steel stringers provide good estimations of LDFs for FRP-deck-on-steel-girder bridges. The lever rule can be used as an appropriately conservative design method to predict the LDFs of FRP-deck-on-steel-girder bridges.<br>Ph. D.
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Rice, Kolten Dewayne. "Bending Behavior of Concrete Beams with Fiber/Epoxy Composite Rebar." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/9062.
Full textAbstract:
This research explores the use of carbon/epoxy and fiberglass/epoxy fiber-reinforced polymer (FRP) composite rebar manufactured on a three-dimensional braiding machine for use as reinforcement in concrete beams under four-point bending loads. Multiple tows of prepreg composite fibers were pulled to form a unidirectional core. The core was consolidated with spirally wound Kevlar fibers which were designed to also act as ribs to increase pullout strength. The rebar was cured at 121â—¦C (250â—¦F) in an inline oven while keeping tension on the fibers. Five configurations of reinforcing bars were used in this study as reinforcement in concrete beam specimens: carbon/epoxy rebar and fiberglass/epoxy rebar were manufactured on the three-dimensional braiding machine and cured in an inline oven while still under tension immediately after production; carbon/epoxy rebar was manufactured by IsoTruss industries on the three-dimensional braiding machine and was rolled and stored before curing; fiberglass/epoxy rebar was purchased from American Fiberglass; conventional No. 4 steel rebar was also purchased. All bars were embedded in 152 cm (60 in) long, 11 cm (4.5 in) wide, and 15 cm (6.0 in) tall concrete beams. Beams were tested under four-point bending loads after which three 30 cm (12 in) specimens were taken from the ends of each configuration to be tested under axial compression loads in order to investigate the effects of the concrete voids on the concrete strength. Concrete beams reinforced with BYU glass/epoxy rebar manufactured on the three-dimensional braiding machine exhibited 5% greater compression bending stress and 11% greater tension bending stress than concrete beams reinforced with industry manufactured glass/epoxy rebar. Concrete beams reinforced with BYU carbon/epoxy rebar manufactured on the three-dimensional braiding machine exhibited 18% lower compression bending stress and 64% lower tension bending stress than concrete beams reinforced with industry manufactured carbon/epoxy rebar. BYU glass/epoxy rebar has a 3% greater stiffness and 1% greater displacement than industry manufactured glass/epoxy rebar and BYU carbon/epoxy rebar has a 40% greater bending stiffness and 19% lower displacement than industry carbon/epoxy rebar. BYU carbon/epoxy rebar has 49% lower compression bending stress, 1% lower tension bending stress, 28% lower displacement, and a 68% greater bending stiffness than BYU glass/epoxy rebar. BYU glass/epoxy rebar has 38% greater compression bending stress, 30% lower tension bending stress, 26% greater center displacement, and a 105% lower bending stiffness than conventional steel. BYU carbon/epoxy rebar has 8% lower compression bending stress, 31% lower tension bending stress, and 22% lower bending stiffness than steel. The deflections of steel reinforced concrete and BYU carbon/epoxy reinforced concrete are comparable with steel rebar displaying a 1% greater center displacement than BYU carbon/epoxy rebar.
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Coker, Rick. "An investigation into the feasibility and application of fibre composites to flatbed semi-trailers." University of Southern Queensland, Faculty of Engineering and Surveying, 2003. http://eprints.usq.edu.au/archive/00001417/.
Full textAbstract:
The highly competitive nature of the transportation industry has produced significant demand for increased equipment efficiency. This has been manifested in attempts to increase carrying capacity whilst lowering running costs. While these factors remain at the forefront of trailer design, the dependence on steel as the primary material has limited the extent to which these goals are realised. The advantages associated with the use of fibre composite materials in automotive applications have been well documented, demonstrating that the substitution of steel with fibre composite materials greatly increases the scope for tare mass reduction. However, to fully utilise the advantages produced through the use of fibre composites, it is necessary to formulate a design philosophy that incorporates the selection of materials and the definition of acceptable performance of both the material and the trailer. This dissertation addresses this broad subject. Within this greater context, this study addresses the incorporation of fibre composite materials into semi-trailers, with the significant issues being divided into two areas: - The development of a design philosophy, intended specifically to address the application of fibre composites to semi-trailers. - The design, analysis and experimental validation of a new type of fibre composite trailer chassis, utilising the aforementioned design philosophy. This PhD project is a foundational study on the suitability of fibre composite materials in the heavy transportation industry, primarily focusing on a practical assessment of the potential for tare mass reduction. The work presented in this dissertation is seen to provide a basis for fibre composite trailer design, in addition to a foundation upon which further investigation into this field can be made. The major outcomes of this project include, amongst others: - The definition of significant load cases and trailer classifications · The development of a design philosophy suited specifically to FRP semi-trailers - The establishment of selection criteria which identifies appropriate FRP materials for use in this application - The development of a new type of FRP chassis for a flatbed semi-trailer - Validation of the design philosophy through experimental testing - Affirmation of the potential of FRPs in application to flatbed semi-trailers
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Kaymak, Yalcin. "A Composite Frame/joint Super Element For Structures Strengthened By Externally Bonded Steel/frp Plates." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1052547/index.pdf.
Full textAbstract:
A materially non-linear layered beam super element is developed for the analysis of RC beams and columns strengthened by externally bonded steel/FRP plates. The elasto-plastic behavior of RC member is incorporated by its internally generated or externally supplied moment-curvature diagram. The steel plate is assumed to be
elasto-plastic and the FRP laminate is assumed to behave linearly elastic up to
rupture. The thin epoxy layer between the RC member and the externally bonded lamina is simulated by a special interface element which allows for the changing failure modes from steel plate yielding/FRP plate rupture to separation of the bonded plates as a result of bond failure in the epoxy layer. An empirical failure criterion based on test results is used for the epoxy material of the interface.
The most critical aspect of such applications in real life frame structures is the anchorage conditions at the member ends and junctions. This has direct influence on the success and the effectiveness of the application. Therefore, a special corner piece anchorage element is also considered in the formulation of the joint super
element, which establishes the fixity and continuity conditions at the member ends
and the joints.
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Bdeir, Zeid. "Deflection-based design of fiber glass polymer (FRP) composite sheet pile wall in sandy soil." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33956.
Full textAbstract:
Fiber Reinforced polymer composite materials offer great potential for waterfront structural applications due to their excellent corrosion resistance, and high strength to weight ratio.<br>The purpose of this thesis is to develop a deflection based design approach for composite sheet pile wall, based on the traditional free-earth support method, but modified to allow the use of deflection criterion. With a simplified earth pressure loading on the wall, the relationship between maximum bending moment and maximum bending deflection and the relationship between maximum shear force and maximum shear deflection were established. 16 case studies were carried out to include walls ranging from 1.5m to 4.5 m tall and water level to wall height ratio from 0.1 to 0.4. Two deflection limits, L/60 and L/100 were employed in developing the design charts.<br>To implement the deflection based design, the proper characterization of flexural rigidity (EI) and shear rigidity (KAG) of the sheet pile panels was vital. Tests were conducted on the connected panels to obtain the rigidities. (Abstract shortened by UMI.)
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Neagoe, Catalin Andrei. "Structural performance of FRP-concrete hybrid beams with flexible shear connection." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/397749.
Full textAbstract:
La sostenibilidad de los edificios y de las infraestructuras públicas es un tema de importancia reciente puesto en discusión por la comunidad de ingeniería. La necesidad de diseñar estructuras con bajos requerimientos de mantenimiento y durabilidad a largo plazo puede ser resuelta mediante la introducción de nuevos materiales de construcción o la implementación de sistemas estructurales innovadores. En este sentido, los polímeros reforzados con fibras (FRP) representan una de las soluciones en el campo de la ingeniería civil que ofrecen resultados prometedores. Para optimizar el uso de secciones de FRP los investigadores han propuesto la creación de sistemas híbridos donde se combinan materiales compuestos con materiales convencionales, tales como el hormigón. Las soluciones híbridas mejoran la rigidez, la ductilidad y la resistencia a pandeo de los elementos aislados de material compuesto. Debido a la novedad y a la variedad de soluciones híbridas, la tecnología requiere de la realización de más ensayos experimentales para valorar su viabilidad. Además, en la actualidad hay una falta de códigos prescriptores y normas que ayuden al diseño de estructuras construidas con perfiles compuestos y, por consiguiente, los elementos mixtos requieren del desarrollo de modelos predictivos fiables. Por lo tanto, la presente investigación tiene como objetivo estudiar el comportamiento estructural de vigas híbridas hechas de perfiles pultrusionados de FRP unidos a losas de hormigón, mediante la realización de una investigación experimental, analítica y numérica. Puesto que los efectos de deslizamiento en la interfaz han sido mayoritariamente ignorados en el pasado, la tesis se centra también en la influencia de la flexibilidad de la conexión sobre el comportamiento de flexión. Con respecto a la campaña experimental, se han fabricado y ensayado a flexión ocho vigas de perfiles de FRP de fibra de vidrio (GFRP) y hormigón, con conectores mecánicos en el rasante. También se ha comparado su comportamiento con respecto a vigas de hormigón armado equivalentes y perfiles estructurales individuales de GFRP. Previamente a dichos ensayos, se propuso un procedimiento eficaz de caracterización no destructiva para la obtención de las propiedades elásticas de los materiales que componían los especímenes, mediante el uso de un análisis de la respuesta a la vibración libre. En general, los ensayos de flexión han demostrado la alta eficiencia estructural de la solución de viga híbrida y han subrayado la importancia de tener en cuenta la flexibilidad de conexión del rasante. También se ha desarrollado un procedimiento analítico para el diseño de vigas mixtas de FRP-hormigón bajo cargas a corto plazo. Se han propuesto ecuaciones de diseño para los estados límite de servicio y último en función de la interacción completa o parcial del rasante. Además, se ha analizado la viabilidad de utilizar fórmulas aproximadas para cuantificar los efectos del deslizamiento entre capas y su repercusión en la evaluación de los desplazamientos, la rigidez a flexión, la capacidad de flexión y las distribuciones de tensiones. Debido a la mejora de la precisión de las expresiones que representan la flexibilidad de la conexión del rasante, el procedimiento analítico propuesto ha sido capaz de capturar de manera adecuada el comportamiento estructural. Por último, en referencia a los análisis numéricos, se han desarrollado modelos de elementos finitos capaces de simular el comportamiento fundamental de vigas híbridas con conectores tipo perno. El modelo que representó las no linealidades en el material, en los contactos y en la geometría fue el que ofreció los mejores resultados en comparación con los datos experimentales y las estimaciones analíticas. El aplastamiento del hormigón en la losa y su fisuración, los efectos de rigidización post fisuración, la fricción de la interfaz y el comportamiento elasto-plástico de los conectores fueron tomados en consideración.<br>Sustainability of buildings and public infrastructure is a relatively recent topic put into discussion by the engineering community. A solution to designing structures that have long-term durability and low maintenance requirements is to introduce new construction materials or to implement new structural systems. In this regard, fiber reinforced polymers (FRP) represent one of the novel solutions in the civil engineering field that offer promising results.
To optimize the use of FRP shapes, researchers have proposed to form hybrid structural systems by combining the composite materials with conventional materials, such as concrete, in order to improve on the stiffness, ductility, and buckling resistance of single FRP members. However, due to the novelty and wide variety of hybrid elements, the technology demands further experimental testing to prove its viability. In addition, because there is a current lack of mandatory codes for the design of structures built with composite profiles and consequently FRP-concrete members, reliable predictive models have to be developed. Addressing the above-mentioned issues is essential in lessening the introduction of advanced composite materials in common types of public works and constructions.
The present research aimed thus to study the structural performance of hybrid beams made of FRP pultruded profiles attached to concrete slabs by carrying an experimental, analytical, and numerical investigation. Since interface slip effects had been largely overlooked in the past, the thesis focused also on the influence of the connection flexibility over bending behavior.
With respect to the developed experimental campaign, eight glass FRP-concrete hybrid beams with mechanical shear connectors were fabricated and their flexural behavior was assessed against that of equivalent reinforced concrete beams and single GFRP structural profiles. The variables of the research were the type of hybrid cross-section and the concrete strength class. The laboratory campaign was divided in two phases depending on the specific test setup configuration, and observations were made regarding the short-term behavior of the novel elements under positive bending moments. Previous to the experimental tests, a nondestructive characterization procedure was proposed for obtaining the elastic properties of the constitutive materials of hybrid members in a reduced amount of time, by using an analysis of the free vibration response. Overall, the bending tests have demonstrated the high structural efficiency of the hybrid beam solution and have underlined the importance of accounting for shear connection deformability.
An analytical procedure was introduced for the design of FRP-concrete beams under short-term loading. Design equations for the serviceability and ultimate limit states were proposed in function of complete or partial shear interaction assumptions. The feasibility of using simplified formulas to quantify for interlayer slip effects was studied in evaluating deflections, flexural stiffness, bending capacities, normal and shear stress distributions. Due to the improved precision of the expressions that had considered the shear connection flexibility, the proposed analytical procedure was able to capture appropriately the structural behavior and performance of the specimens.
Finally, referring to the numerical analyses, predictive finite element models capable of simulating the fundamental behavior of FRP-concrete beams with bolted joints were developed. The model that included material, contact, and geometry nonlinearities offered the best results in comparison with the experimental data and analytical estimations. Concrete slab crushing and cracking, tension stiffening effects, interface friction, and the elasto-plastic behavior of the shear connectors were all taken under consideration.
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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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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.
Full textAbstract:
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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Hayes, Michael David. "Characterization and Modeling of a Fiber-Reinforced Polymeric Composite Structural Beam and Bridge Structure for Use in the Tom's Creek Bridge Rehabilitation Project." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/35852.
Full textAbstract:
<p> Fiber reinforced polymeric (FRP) composite materials are beginning to find use in construction and infrastructure applications. Composite members may potentially provide more durable replacements for steel and concrete in primary and secondary bridge structures, but the experience with composites in these applications is minimal. Recently, however, a number of groups in the United States have constructed short-span traffic bridges utilizing FRP members. These demonstration cases will facilitate the development of design guidelines and durability data for FRP materials. The Tom's Creek Bridge rehabilitation is one such project that utilizes a hybrid FRP composite beam in an actual field application. </p>
<p> This thesis details much of the experimental work conducted in conjunction with the Tom's Creek Bridge rehabilitation. All of the composite beams used in the rehabilitation were first proof tested in four-point bending. A mock-up of the bridge was then constructed in the laboratory using the actual FRP beams and timber decking. The mock-up was tested in several static loading schemes to evaluate the bridge response under HS20 loading. The lab testing indicated a deflection criterion of nearly L/200; the actual field structure was stiffer at L/450. This was attributed to the difference in boundary conditions for the girders and timber panels. </p>
<p> Finally, the bridge response was verified with an analytical model that treats the bridge structure as a wood beam resting upon discrete elastic springs. The model permits both bending and torsional stiffness in the composite beams, as well as shear deformation. A parametric study was conducted utilizing this model and a mechanics of laminated beam theory to provide recommendations for alternate bridge designs and modified composite beam designs. </p><br>Master of Science
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Tascioglu, Cihat. "Impact of Preservative Treatments and Fungal Exposure on Phenolic Fiber Reinforced Polymer (FRP) Composite Material Utilized in Wood Reinforcement." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/TasciogluC2002.pdf.
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