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Investigation in Alternative Devices for Joint Load Transfer in Jointed Concrete PavementMann, James Clifford 01 1900 (has links)
Conventional construction of Jointed Plain Concrete Pavements (JPCP) in Canada consists of placing a round steel epoxy-coated dowel at the mid height of the pavement. Steel dowels reduce stepping at the joint to improve comfort and reduce the stress concentration on the support layer beneath the pavement. Most importantly they transfer load and are commonly referred to as load transfer devices. Problems with dowel bar deterioration, including corrosion causes the slab joint to lock and cause stress concentrations as the slab expands and or contracts and curls due to thermal and shrinkage straining occurring in the concrete. In this research, alternative joint load transfer devices are presented and compared to conventional steel dowels. Four device alternatives are developed and evaluated: a Glass Fibre Reinforced Polymer (GFRP) I-beam placed directly on the base material; GFRP tapered plates; a continuous horizontal V device; and a continuous horizontal pipe device both placed directly on the support layer. The two devices that are continuous run the length of the joint similar to a shear key.
The GFRP tapered plate and I-beam, as well as conventional steel dowels, were analyzed in a wheel path sized three dimensional finite element model for wheel loading and static loading applied to either side of the joint. An experimental testing program was developed to test joint load transfer capabilities of each device when subjected to a static wheel load applied to either side of the joint. The GFRP tapered plates and I-beams were shown to transfer load based on the results from the wheel path finite element model and experimental testing program. The differential joint deflection, stress concentrations and plastic straining occurring in the concrete is not reduced with either the tapered plate or I-beam compared to a dowel under wheel loading. In addition, a similar plastic straining area identified in the finite element models were noticed as an area of damage in the experimental testing program.
All of the devices developed are analyzed in a quarter slab three dimensional finite element model with shrinkage and thermal strains as well as wheel loading applied to the slab to simulate service loading. A detailed investigation into the stress distribution around the devices and the differential deflection at the joint through the service loading applied is presented in this paper. Similarly to the wheel path investigation the stress concentration in the tapered plate and I-beams are greater than conventional dowels and also have greater differential deflection occurring at the joint. Both the continuous Horizontal V and Horizontal Pipe device reduce stress and plastic straining in the concrete during the service load analysis compared to dowels. During daytime wheel loading the differential deflection in the joint is the lowest with no noticeable stepping occurring at the joint with the Horizontal V device; however is greater than conventional steel dowels under nighttime wheel load application. The differential deflection with the Horizontal Pipe during day and night straining and wheel loading is similar to conventional steel dowels.
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Investigation in Alternative Devices for Joint Load Transfer in Jointed Concrete PavementMann, James Clifford 01 1900 (has links)
Conventional construction of Jointed Plain Concrete Pavements (JPCP) in Canada consists of placing a round steel epoxy-coated dowel at the mid height of the pavement. Steel dowels reduce stepping at the joint to improve comfort and reduce the stress concentration on the support layer beneath the pavement. Most importantly they transfer load and are commonly referred to as load transfer devices. Problems with dowel bar deterioration, including corrosion causes the slab joint to lock and cause stress concentrations as the slab expands and or contracts and curls due to thermal and shrinkage straining occurring in the concrete. In this research, alternative joint load transfer devices are presented and compared to conventional steel dowels. Four device alternatives are developed and evaluated: a Glass Fibre Reinforced Polymer (GFRP) I-beam placed directly on the base material; GFRP tapered plates; a continuous horizontal V device; and a continuous horizontal pipe device both placed directly on the support layer. The two devices that are continuous run the length of the joint similar to a shear key.
The GFRP tapered plate and I-beam, as well as conventional steel dowels, were analyzed in a wheel path sized three dimensional finite element model for wheel loading and static loading applied to either side of the joint. An experimental testing program was developed to test joint load transfer capabilities of each device when subjected to a static wheel load applied to either side of the joint. The GFRP tapered plates and I-beams were shown to transfer load based on the results from the wheel path finite element model and experimental testing program. The differential joint deflection, stress concentrations and plastic straining occurring in the concrete is not reduced with either the tapered plate or I-beam compared to a dowel under wheel loading. In addition, a similar plastic straining area identified in the finite element models were noticed as an area of damage in the experimental testing program.
All of the devices developed are analyzed in a quarter slab three dimensional finite element model with shrinkage and thermal strains as well as wheel loading applied to the slab to simulate service loading. A detailed investigation into the stress distribution around the devices and the differential deflection at the joint through the service loading applied is presented in this paper. Similarly to the wheel path investigation the stress concentration in the tapered plate and I-beams are greater than conventional dowels and also have greater differential deflection occurring at the joint. Both the continuous Horizontal V and Horizontal Pipe device reduce stress and plastic straining in the concrete during the service load analysis compared to dowels. During daytime wheel loading the differential deflection in the joint is the lowest with no noticeable stepping occurring at the joint with the Horizontal V device; however is greater than conventional steel dowels under nighttime wheel load application. The differential deflection with the Horizontal Pipe during day and night straining and wheel loading is similar to conventional steel dowels.
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Test av förankringar för sandwichelement - en jämförelse mellan två kopplingssystem av glasfiber / Test of anchors in sandwich elements - a comparison between two glass fiber connection systemsWerngren Karlsson, Robin, Carhuallanqui Obregon, Paul Ericson January 2022 (has links)
Prefabricerade sandwichelement kommer att produceras till Linnéskolan i Älmhult av Torps Byggelement AB. Ett sandwichelement består av två lager betong (fasad och bärande skikt) med isolering mellan de två skikten. Dessa sandwichelement hade till en början förankringssystemet Thermopin tillverkade av B.T. Innovation, men på grund av produktion- och leveransproblem så ersattes detta förankringssystem mot Isolink som tillverkas av Schöck. Isolink och Thermopin är två förankringssystem tillverkade av glasfiberarmerade plaststänger (GFRP). Sandwichelementen som kommer att användas i Linnéskolan använder sig av isoleringen Kooltherm tillverkad av Kingspan. I detta arbete jämförs förankringssystemens bärförmågor i form av utdragskapacitet. Beräkningar för kapacitet mot vidhäftningsbrott, utdragsbrott och brott i stångmaterial görs för de båda systemen. Utöver detta testas även bärförmågan i form av utdragskapacitet för isolering Kooltherm. 12 testprover, som tillverkades och levererades av Torps Byggelement AB, utsätts för utdragslaster till brott uppstod. Endast de förankringssystem som bär vinkelrät mot skikten testades. De 12 testproverna var uppdelade på följande vis: Fyra tester med Thermopin, fyra tester med Isolink samt fyra tester med endast isoleringen Kooltherm. De testprover med Isolink-systemet gav ett utdragsbrott vid 18.9 kN. Thermopin gav ett spjälkningsbrott vid 14.9 kN. Kooltherm gav brott i isoleringen vid 1.3 kN. Då Isolink fick ett vidhäftningsbrott är det viktigt med en god vidhäftning mellan förankringssystemet och omkringliggande betong. Vibrering av betongen i flera steg vid användning av Isolink kan därför anses vara viktig. Thermopin fick ett spjälkningsbrott då tillverkarens minsta avstånd till kant inte uppfylldes med testproverna. Det går med stor sannolikhet att säga att Thermopin inte hade fått ett utdragsbrott även om minsta avstånd till kant uppfylldes, mest troligt är att ett konbrott hade uppstått. / Prefabricated sandwich elements will be produced to Linnéskolan in Älmhult by Torps Byggelement AB. A sandwich element is built up by two layers of concrete (facade- and load bearing layer) with insulation separating the two layers. These sandwich elements were intended to have the anchors Thermopin produced by B.T. Innovation but due to delivery problems, this connection system was replaced with Isolink made by Schöck. Isolink and Thermopin are two anchors consisting of glass fiber reinforced plastic bars (GFRP). The sandwich elements that will be used in Linnéskolan will have the insulation Kooltherm made by Kingspan. This work is comparing the two connection systems in load bearing capacity by pull-out load tests. Calculations for pull-out failure, concrete failure and anchor failure were done for both of the connection systems. The load bearing capacity was also to be checked for the Kooltherm insulation by pull-out load tests. 12 test specimens were manufactured and delivered by Torps Byggelement AB. Only the anchors perpendicular to the concrete layers were tested. The 12 test specimens were divided as follows: four tests with Thermopin, four tests with Isolink and four tests without a connection system with only the Kooltherm insulation. The test specimens with Isolink gave a pull-out load at 18.9 kN. Thermopin gave a splitting failure at 14.9 kN. Kooltherm insulation gave a failure in the insulation at 1.3 kN. Due to Isolink getting a pull-out load failure, it is important that the bond between the anchor and the surrounding concrete is strong. Compacting of the concrete in multiple steps when using the Isolink-system can be considered important. The test specimens with the Thermopin-system got a splitting failure due to the manufacturers requirement on minimum edge distance not being achieved in the test specimens. It is proper to state that it is very unlikely that a pull-out failure would occur in the Thermopin test specimens even if the minimum edge distance was achieved. Most likely a concrete-cone failure would have occurred.
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Využití vnitřní kompozitní výztuže při návrhu odolných betonových konstrukcí / The use of internal composite reinforcement in the design of durable concrete structuresKoriťáková, Martina January 2022 (has links)
The diploma thesis deals with processing of determining the shear strength of concrete structures reinforced with composite reinforcement, subjected to shear force, according to five different design approaches. The theoretical part of the thesis is closely related to the project FW01010520 - "Development of bent composite reinforcement for environmentally exposed concrete constructions", which is realized at the Institut of Concrete and Masonry Structures, Faculty of Civil Engineering, Brno University of Technology. The project deals with the shear strength of concrete beams reinforced with steel and composite reinforcement in various combinations. Then the load-bearing results gained within the project are compared with the values obtained by calculations according to the solved design approaches and computer software Atena Science. The second part of the diploma thesis deals with the static design and assessment of the cell structure. The cell is designed as a room inside of the medical building, where is placed device of magnetic resonance which is the reason why the cell is reinforced with non-magnetic composite reinforcement.
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FRP:s användning inom brokonstruktioner / FRP's use in bridge structuresAbdi Yussuf, Yusuf, Jalal Ibrahim, Zand January 2019 (has links)
I dagsläget är de flesta broar i Sverige tillverkade med betong eller stål. Dessa broar är många gånger förknippade med stora kostnader som ofta beror på underhåll och reparation. FRP, som står för Fiber Reinforced Polymer, är ett relativt nytt material i bärande stommar men är ett väl etablerat material i förstärkningssammanhang. I Europa och i synnerhet Nederländerna finns det flertal broar byggda i FRP. Men på grund av brist på normer och regelverk att luta sig emot sker det sällan någon form av brokonstruktion med FRP i Sverige. Detta examensarbete syftar till att undersöka befintliga normer och studera hur materialet FRP används vid förstärkning och konstruktion av broar. Vidare syftar även arbetet till att undersöka egenskaperna hos FRP som byggmaterial och jämföra det med konventionella material som stål och betong. FRP, också benämnd fiberkomposit, är ett kompositmaterial som kan sammanställas på flera olika sätt. Genom olika material som kombineras och olika tillverkningsprocesser som används kan man på så sätt ge individuell utformning till materialet för dess användning. Fördelarna med FRP är många, men i allmänhet har det god styrka, god beständighet samtidigt som det har en låg vikt. Detta resulterar i att inom brokonstruktion så ger det strukturen en minskad egenvikt, vilket i sin tur underlättar en mängd olika saker. Detta arbete visar på att FRP-material har fördelaktiga egenskaper och kan i vissa situationer vara mer gynnsamt att använda än stål eller betong. Dock som tidigare påpekat saknas det specifika Eurokoder för detta material. Däremot är vi säkra på att introduktionen av en ny Eurokod samt med uppmuntran från myndigheter kommer användningen av FRP inom brokonstruktion utan tvekan öka. / At present, most bridges in Sweden are made with concrete or steel. These bridges are often associated with high costs, which often depend on maintenance and repair. FRP, which stands for Fiber Reinforced Polymer, is a relatively new material in load-bearing structures but is a well- established material in the context of reinforcement. In Europe and in particular the Netherlands, there are several bridges built in FRP. But due to a lack of norms and regulations to lean against, there is rarely any kind of FRP bridge construction in Sweden. The aim of this thesis is to examine existing norms and study how the material FRP is used in the reinforcement and construction of bridges. Furthermore, this thesis also aims to investigate the properties of FRP as building material and compare it with conventional materials such as steel and concrete. FRP, also called fiber-composite, is a composite material that can be assembled in several different ways. Through various materials that are combined and different manufacturing processes used, one can thus provide individual designs for the material. The benefits of FRP are many, but generally it has good strength, good durability while having a low weight. This results in that within bridge construction, it gives the structure a reduced self-weight, which in turn facilitates a variety of things. This thesis shows that FRP materials have advantageous properties and in some situations can be more favorable to use than steel or concrete. However, as previously pointed out, there are no specific Eurocodes for this material. However we are sure that the introduction of a new Eurocode and encouragement from authorities will undoubtedly increase the use of FRP in bridge construction.
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[pt] DUCTILIDADE E REDISTRIBUIÇÃO DE MOMENTOS EM VIGAS DE CONCRETO ARMADO COM BARRAS DE GFRP / [en] DUCTILITY AND MOMENT REDISTRIBUTION IN GFRP REINFORCED CONCRETE BEAMSVITOR DE MATTOS CARVALHO 16 December 2021 (has links)
[pt] A utilização de barras de polímero reforçado com fibra contínua (Fiber
reinforced polymer, ou FRP) como reforço no concreto armado vem
ganhando relevância no mercado devido às suas propriedades não
corrosivas, alta resistência, durabilidade e transparência eletromagnética.
Por outro lado, o comportamento frágil e o baixo módulo de elasticidade
das barras de FRP limita sua aplicação e difusão no mercado da construção
civil. Sob esta perspectiva, este trabalho avalia, em uma primeira etapa, o
incremento de ductilidade em vigas de concreto armado com barras de
GFRP (Glass fiber reinforced polymer) por meio da adição de fibras
dispersas de vidro AR (álcali resistente) à matriz cimentícia e/ou pelo
confinamento do concreto nas regiões críticas com o uso de estribos de
GFRP. Para tal, são reportados e discutidos os resultados de ensaios
realizados em oito vigas isostáticas sob flexão de quatro pontos, sendo
quatro superarmadas e quatro são subarmadas. Em geral, as estratégias
adotadas se mostraram bem-sucedidas apenas para as vigas
superarmadas, que passaram a apresentar falhas caracterizadas por
formação de cunha de compressão e grandes deslocamentos até a ruptura.
Para avaliação da ductilidade, foram adotados dois métodos distintos: um
baseado em energia (índice de ductilidade, (micro)E) e outro baseado em
deformação (fator de performance, (micro)M). Para as vigas subarmadas, o fator
de performance por meio da curvatura e o fator de performance por meio
da deflexão representaram maiores incrementos de ductilidade para a viga
com adição de fibras dispersas devido ao efeito do enrijecimento à tração,
enquanto o índice de ductilidade não se mostrou uma boa alternativa para
estas vigas. Para as vigas superarmadas, o fator de performance por meio
da curvatura e o índice de ductilidade representaram maiores incrementos
de ductilidade para as vigas com confinamento, enquanto no fator de
performance por meio da deflexão, o incremento de ductilidade foi mais
significativo para as vigas com adição de fibras. Em uma segunda etapa, é
avaliada a capacidade de redistribuição de momentos fletores em três vigas
hiperestáticas de dois vãos reforçadas com barras de GFRP contendo
maior taxa de armadura inferior, bem como configurações distintas de
armadura transversal e uso de fibras. Foi possível observar um aumento
do momento nos centros dos vãos de 30 por cento e uma redução no momento no
apoio central superior a 60 por cento, quando comparados aos momentos elásticos,
que confirmam a influência da configuração da armadura na distribuição de
esforços. / [en] The use of continuous fiber reinforced polymer (FRP) bars as an internal
reinforcement for concrete has gained attention due to its non-corrosive
properties, high resistance, requiring electromagnetic transparency. On the
other hand, the brittle behavior and low modulus of elasticity of FRP bars
limit their application and diffusion in the civil construction market. From this
perspective, this work evaluates, firstly, the increase of ductility in GFRP
(glass-fiber reinforced polymer) reinforced concrete beams by adding
dispersed alkali-resistant (AR) glass fibers to the cementitious matrix and/or
by confinement of the concrete in critical regions with the use of GFRP
stirrups. To accomplish this task, the results of tests performed on eight
statically determinate beams under four-point bending are reported and
discussed, four of which are under-reinforced and four are over-reinforced.
In general, the strategies adopted were successful only for the overreinforced
beams, whose failures were characterized by the formation of a
compression wedge and large displacements before rupture. For ductility
evaluation, two distinct methods were adopted: one based on energy
(ductility index, (micro)E) and another based on deformation (performance factor, (micro)M). For under-reinforced beams, the performance factor through curvature
and the performance factor through deflection led to greater ductility
increments for the beam with the addition of dispersed fibers due to the
tensile stiffening effect, while the ductility index did not lead to good results.
For the over-reinforced beams, the performance factor through curvature
and the ductility index were able to describe the greater ductility increments
for the confined beams, while the performance factor through deflection
resulted in a greater ductility increment for the beams with discrete fiber
addition. In a second step, the capacity of redistribution of moments in three
statically indeterminate GFRP reinforced concrete beams with two spans
and with a higher lower reinforcement ratio was evaluated for two different
configurations of transverse reinforcement and for the use of fibers. It was
possible to observe an increase in the positive moment of 30 percent (center of
span) and a reduction in the negative moment (central support) greater than
60 percent, when compared to the elastic moments, confirming the influence of
the reinforcement configuration on the distribution of internal forces.
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[pt] AVALIAÇÃO DE MECANISMOS DE TRANSFERÊNCIA DA FORÇA CORTANTE E RESISTÊNCIA DE VIGAS DE CONCRETO REFORÇADO COM BARRAS DE FIBRA DE VIDRO / [en] EVALUATION OF SHEAR TRANSFER MECHANISMS AND STRENGTH OF GFRP REINFORCED CONCRETE BEAMSDANIELLE DUQUE ESTRADA PACHECO 10 October 2019 (has links)
[pt] Este trabalho tem como objetivo avaliar a resistência à força cortante de vigas de concreto reforçado com barras de fibras de vidro e investigar a contribuição dos diferentes mecanismos de transferência do esforço cortante para a resistência final da viga. Um programa experimental foi conduzido, incluindo ensaios para: caracterização do material, para avaliar o efeito de pino, para avaliar o engrenamento dos agregados e, por fim, ensaios de flexão de quatro pontos em vigas. Diferentes parâmetros foram investigados, como a quantidade de barras longitudinais para o efeito de pino, dimensão máxima do agregado graúdo para engrenamento dos agregados e a presença de estribos para os ensaios de vigas. O monitoramento do desenvolvimento da fissura crítica foi realizado com auxílio de correlação de imagem digital (digital image correlation, DIC, em inglês). Os resultados mostraram que não foi evidenciada diferença no comportamento de efeito de pino e de engrenamento dos agregados através dos ensaios realizados. Para os ensaios de vigas, observou-se que todos os espécimes apresentaram ruptura por tração da diagonal crítica e, para vigas sem estribos, a ação do efeito de pino pareceu contribuir significativamente para a resistência ao cisalhamento após a fissura, quando a carga diminui e as deflexões aumentam, resultado do menor engrenamento dos agregados à medida que a fissura se abre. Foi observado que a presença de estribos aumentou em até três vezes a resistência ao cortante das vigas ensaiadas e que houve ruptura do estribo na parte da dobra. / [en] This work aims to evaluate the shear strength of reinforced concrete beams with glass fiber reinforced polymer bars and to investigate qualitatively the contribution of the different shear transfer mechanisms to the final strength of the beam. An experimental program was conducted, including material characterization, dowel action tests, push-off tests, and finally, four-point bending tests on beams. Different parameters were investigated, such as the number of longitudinal bars for dowel action effect, maximum size of the coarse aggregate for aggregate interlock and the presence of stirrups for the beam tests. The monitoring of the development of the critical crack was performed with the aid of digital image correlation (DIC). The results showed that there was no difference in the behavior of the dowel action effect and the aggregate interlock through the tests performed. For beam tests, it was observed that all the specimens exhibited a concrete diagonal tension failure and for beams without stirrups, dowel action seemed to provide significant contribution to the shear strength after the crack, when the load reduces and the deflections increases, resulting from the loss of aggregate interlock as the crack opens. It was also observed that the presence of stirrups increased up to three times the shear strength of the beams tested and that there was rupture of the stirrup at the bent region.
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Entwicklung und Verifizierung eines vorlochfreien mechanischen Fügeverfahrens zum Verbinden von Leichtmetallen und Faser-Kunststoff-Verbunden / Development and varification of a mechanical joining process for joining lightweight metals and fibre reinforced plastics without the need of a preholePodlesak, Frank 27 April 2017 (has links) (PDF)
Die Mischbauweise stellt eine Möglichkeit dar, insbesondere im Automobilbau, aber auch in anderen Industriezweigen Leichtbau zu betreiben. Dazu werden verschiedenartige Werkstoffe miteinander kombiniert. Vorzugsweise handelt es sich um Kombinationen aus faserverstärkten Kunststoffen und Leichtmetallen. Nach dem Motto “Der richtige Werkstoff am richtigen Ort” können so belastbare und gleichzeitig leichte Konstruktionen realisiert werden. Eine große Herausforderung besteht dabei jedoch im Fügen solch unterschiedlicher Werkstoffe. Aufgrund großer Unterschiede in Bindungsart und Schmelztemperatur sind klassische Fügeverfahren nicht anwendbar. Zum Verbinden von Metallen mit Faser- Verbund-Werkstoffen (FKV) wurden deswegen vorhandene Technologien adaptiert oder neue entwickelt. Im Rahmen dieser Dissertation wurde mit dem modifizierten Blindnieten ein neuer Lösungsansatz entwickelt, der sowohl mechanische als auch thermische Fügeverfahren miteinander kombiniert. Dazu wird ein rotierender Blindniet in sich überlappende Bleche getrieben und das darunter liegende Material unter Ausbildung einer Hülse aus dem Oberblech verdrängt. Anschließend wird der Niet ausgeformt und der Prozess ist abgeschlossen. Durch die Reibwärme wird die thermoplastische Matrix des FKV geschmolzen und die Fasern werden beweglich und können verdrängt werden. Dadurch kommt es zu einer geringeren Faserschädigungen und es können Delaminationen komplett vermieden werden. Untersuchungen wurden vorzugsweise an Materialkombinationen in Mischbauweise durchgeführt. Es wurden Aluminium- und Magnesiumbleche mit verschiedenen FKV mit Glas- oder Kohlefaserverstärkung gefügt. Für eine große Anwendungsbreite wurden ebenso Verbindungen von mehreren Metallblechen untersucht. Alle Kombinationen konnten so gefügt werden, dass in relativ kurzer Prozesszeit eine qualitativ hochwertige Verbindung entsteht. Mit einer geeigneten Parameterwahl sind Fügezeiten unter drei Sekunden möglich. Die mechanisch technologischen Gütewerten zeigen, dass mittels modifiziertem Blindnieten hergestellte Verbindungen mindestens die gleiche Lasten aufnehmen können, wie konventionelle Verfahren. Unter Scherbelastung kann die Belastbarkeit um bis zu 68 % gesteigert werden. Es hat sich gezeigt, dass mit dem neuen Verfahren eine wirtschaftliche Lösung für den Mischbau zur Verfügung steht. / Composite constructions provide an opportunity to introduce lightweight design in automotive and other industries. Therefore different kind of materials are combined. Preferably, these are combinations of fibre reinforced plastics and lightweight metal alloys. With the slogan "the right material at the right place" tough and lightweight constructions can be realized. A big challenge the joining of these different materials. Because of big differences in the chemical bindings and in the melting temperature, conventional joining methods cannot be used. To join fibre reinforced plastics (FRP) existing processes were adapted or newly developed. In the course of this work with the modified blind riveting a new approach was developed, which combines mechanical and thermal joining processes. Therefore a rotating blind rivet is penetrated through two overlapping sheets by deforming the sheet material. After that the rivet is set and the process finished. Because of the friction heat the thermoplastic matrix of the FRP is slightly melted and the fibres can be moved without breaking them. Investigations were done mainly with lightweight material combinations. Sheets made out of aluminum and magnesium were joined with glass or carbon fibre reinforced plastic sheets. For a wider application field also combinations of two metal sheets were investigated. All combinations could be joined in a relatively short cycle time and high quality. So it is possible to reach a joining time of under 3 seconds. Under shear load the strength of joints made by modified blind riveting can be up to 68 % higher than conventional riveted joints. It has been shown that the new process can be exploited economically.
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Punching shear behaviour of GFRP-RC slab-column edge connections with high strength concrete and shear reinforcementMostafa, Ahmed 17 November 2016 (has links)
In this thesis the experimental results of seven full-scale glass fiber-reinforced polymer (GFRP) reinforced concrete (RC) slab-column edge connections are presented. The dimensions of the slabs were 2,800×1,550×200 mm with a square column measuring 300×300×2,200 mm. The test connections were divided into two series. Series I included three connections investigating the effect of flexural reinforcement ratio (0.90, 1.35 and 1.80%) when high strength concrete (HSC) is used, while Series II included four connections investigating the effect of GFRP shear reinforcement type and pattern on normal strength concrete (NSC) connections. Test results showed that increasing the reinforcement ratio increased the punching capacity and the post-cracking stiffness of the HSC connections. Furthermore, the use of headed studs and corrugated bars increased the punching capacity and the deformability of the NSC connections. Test results were compared to the predictions of the Canadian and American design provisions for FRP-RC structures. / February 2017
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Long-Term Deflection Of One-Way Concrete Slab Strips Containing Steel And GFRP ReinforcementDarabi, Mohammadali 14 September 2011 (has links)
Fibre reinforced polymers (FRP’s) are considered an alternative to steel reinforcement in concrete structures because of their noncorrosive nature and nonmagnetic properties. FRP materials are, however, brittle and have a lower stiffness compared to steel. The latter property can lead to deflection and crack control problems in FRP-reinforced concrete flexural members under service loads. A considerable amount of information is available for short-term deflection of FRP-reinforced concrete members, but data on long-term deflections are scarce.
This study presents the results of monotonic (short-term) and sustained (long-term)
loading tests of 12 concrete shallow beams reinforced with either steel or glass FRP
(GFRP) bars. The short-term load-deflection responses of the members are evaluated
using existing deflection prediction models (Branson’s and Bischoff’s), and the long-term deflection results (monitored over a period of one year) are used to evaluate the existing ACI code and CSA standard approaches for estimating long-term deflection. The GFRP-reinforced concrete beams exhibited greater amounts of both immediate deflection (under sustained load) and long-term deflections over time, than the steel-reinforced concrete beams. The long-term deflections of both the steel- and GFRP-reinforced concrete beams are overestimated when using the ACI and CSA approaches. Although ACI Committee 440 recommends use of lower values of the long-term deflection multiplier for GFRP-reinforced concrete beams, results obtained from this study suggest that the same longterm multiplier values may be used for GFRP- and steel-reinforced concrete beams loaded at between 115 to 157 days of concrete age.
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