The use of fiber-reinforced polymer (FRP) composites as a repair and strengthening material for reinforced concrete (RC) members has increased over the past twenty years. The tendency for FRP sheets to debond at loads below their ultimate capacity has prompted researchers to investigate various approaches and designs to increase the efficiency of FRP strengthening systems. Various anchors, wrapping techniques and clamps have been explored to postpone and/or delay the debonding process which results in premature failure. FRP anchors are of particular interest because they can be selected to have the same material properties as the FRP sheets that are installed for strengthening or repair of the RC member and can be done so using the same adhesives and installation techniques. This research study aimed to investigate the effectiveness of using commercially manufactured FRP anchors to secure FRP sheets installed to strengthen and repair RC beams in shear and RC slabs in flexure. Twenty one shear critical RC beams were strengthened in shear with u-wrapped FRP sheets and FRP anchors. Eight RC one-way slabs were strengthened in flexure with FRP sheets and FRP anchors. The test variables include the type of FRP sheets (GFRP,CFRP), type of FRP anchors (CFRP, GFRP) and the strengthening configuration. The test results of the shear critical RC beams revealed that the installation of commercially manufactured FRP anchors to secure externally applied u-wrap FRP sheets improved the shear behaviour of the strengthened beam. The installation of FRP anchors to secure u-wrapped FRP sheets provided an average 15% increase in the shear strength over companion unanchored beams and improved the ductility of failure experienced with the typical shear failure in beams. The use of FRP anchors allowed the FRP sheets to develop their tensile capacity. Premature failure by FRP debonding was eradicated with the presence of FRP anchors and the failure modes of the strengthened beams with FRP anchors was altered when compared to the companion unanchored beam. Additionally, as the width of a u-wrapped FRP sheet was increased; larger increases in strength were obtained when FRP anchors were used. The test results of the flexure critical RC slabs revealed that the installation of commercially manufactured FRP anchors to secure externally applied u-wrapped FRP sheets improved the behaviour of strengthened slabs. Installation of FRP anchors to secure flexural FRP sheets provided an average 17% increase in strength over companion unanchored beams. The use of FRP anchors allowed the FRP sheets to develop their full tensile strength. Premature failure by CFRP debonding was not eliminated with the presence of FRP anchors; rather the critical failure zone was shifted from the bottom soffit of the slab to the concrete/steel rebar interface. The failure modes of slabs with FRP anchors were altered for all specimens when compared to the companion unanchored slab. The effective strain in the FRP sheet was predicted and compared with the experimental results. The efficiency of FRP anchors defined as the ratio of effective strain in the FRP sheet with and without anchors was related to the increase in strength in beams and slabs. A good correlation was established between the FRP anchor efficiency and the increase in strength. A step-by-step FRP anchor installation procedure was developed and a model to predict the number of FRP anchors required to secure a FRP sheet was proposed. This is the most comprehensive examination of beams and slabs strengthened with FRP sheets and FRP anchors conducted to date. This study provides an engineer with basic understanding of the mechanics, behaviour and failure modes of beams and slabs strengthened with FRP sheets and anchors.

All reinforced concrete (RC) design theories are based on the assumption that concrete exhibits a perfect bond with the steel reinforcement. The bond between steel and concrete is essential to the transfer of the load applied from the concrete to the steel reinforcement. When steel bars are corroded, the concrete cracks, and the strength of the bond between the steel bars and the concrete is decreased. Structures such as bridges and marine structures are prone to corrosion. These structures are usually also subjected to repeated loading. Repeated loading can initiate cracks in the concrete surrounding the steel bars that propagate as the number of load cycles increases leading to the destruction of the concrete-steel interface and slip of the steel bars inside the concrete. The combined effect of corrosion and repeated loading reduces the service life of RC structures. This study investigated the effect of anchorage length and confinement from supports, stirrups and carbon fibre reinforced polymer (CFRP) on the bond behaviour of corroded and uncorroded reinforced concrete beams subjected to monotonic and repeated loading. Fifty-seven large-scale reinforced concrete beams (152*254*2000 mm) were tested for the purpose of this study. The variables were stirrup spacing (75 mm and 150 mm), anchorage length (200 mm, 350 mm and 650 mm), corrosion level (mild corrosion and high corrosion level), repair condition (wrapped or unwrapped with FRP sheets in the anchorage zone) and the fatigue load range. From this study, it was found that the resistance to bond stresses (forces) between the steel and concrete were provided mainly by the concrete keys. The bond stresses increased with the number of the concrete keys engaged. The factors that affected the number of concrete keys engaged were: confinement from the supports, confinement from the stirrups, confinement due to wrapping with FRP sheets and change in anchorage length. Decreasing the stirrup spacing from 150 mm to 75 mm increased the number of concrete keys engaged thus increasing the bond capacity and changed the mode of failure under monotonic loading from splitting to pullout. The beams with the first stirrup spacing (150 mm c/c) when tested under repeated loading failed by bond fatigue while the beams with the second stirrup spacing (75 mm c/c) failed by flexure at the end of a debonded region that started from the support. The failure mechanism is discussed for each case. The change in anchorage length from 200 mm to 350 mm increased the static and fatigue bond capacity of the beams by 60% and 12.5% respectively. The debonding for this group of beams (200 mm and 350 mm anchorage length) subjected to monotonic loading started from the pocket and propagated towards the support while the debonding for the 350 mm anchorage length beams subjected to repeated loading started at the location of a crack that widened while fatiguing the beam and propagated towards the support. The change in anchorage length from 350 mm to 650 mm did not affect the monotonic bond capacity of the beams since in this case, debonding was initiated from the supports and the change in anchorage length had little effect. The confinement with FRP sheets caused the concrete keys at both the top and bottom of the bar to be crushed and increased the bond stress of the wrapped beams. The bond strength of the beams repaired with CFRP sheet was governed by the strength of the FRP sheets for all anchorage lengths and corrosion levels. The CFRP repair of the 200 mm anchorage length set of beams increased the capacity of the uncorroded beams by 80% and the capacity of the corroded beams by about 25% under static and repeated loading compared to the control (uncorroded and unrepaired) beam. The CFRP repair of the 350 mm anchorage length set of beams changed the mode of failure from bond to flexure. The fatigue life for the beams varied linearly on a logarithmic scale with the load range applied with a shallow slope. Corroding the 200 mm anchorage length set of beams to a mild corrosion level decreased their fatigue strength by 34% compared to the control beams. Corroding the 350 mm anchorage length set of beams to a mild corrosion level did not affect the fatigue strength for the single beam that failed in bond. Finally a probabilistic approach was used to allow the design engineers to estimate the design fatigue life for similar beams with 95% probability for a given normalized stress ratio.

Fiber reinforced polymer (FRP) deck has some significant advantages compared to concrete deck in use of bridges, such as light self-weight, high stiffness and strength, good durability and easy to install. FRP deck has already been used in some bridge rehabilitation and short span bridges. But for widely used in bridges, FRP deck bridges still need further research. Currently many research efforts focus on the filed tests of FRP deck bridges. Compared to field tests, Finite element analysis also has great advantages, such as low cost and convenient to conduct. Therefore, in this thesis finite element analysis is conducted by ABAQUS on the Boyer Bridge in Pennsylvania. The finite element model is verified by the static field test result. Then a simplified moving truck load is applied on the bridge model in order to analyze the dynamic responses of the FRP deck bridge, including the displacements and stress of each girder at the middle span. The dynamic effect is shown by comparing the dynamic responses and the static responses of the bridge. The connection between the FRP deck and girder is very important to the behavior of the bridge. In this thesis shear studs serve to connect the FRP deck and girder. This thesis also analyzes the effect of shear studs to the dynamic responses of the bridge by changing the number of the shear studs.

Titel               Sverigedemokraterna och Fremskrittspartiet - En kvantitativ innehållsanalys om två kvällstidningars rapportering om Sverigedemokraterna och Fremskrittspartiet efter valet 2014 respektive 2013.   Författare      Julia Alner och Rebecca Nygren   Kurs              Medie- och kommunikationsvetenskap (61-90) 30 hp   Termin           Vårtermin 2015   Syfte             Syftet med uppsatsen är att genom en kvantitativ innehållsanalys se hur reaktionerna efter det norska och svenska valet såg ut i den norska tidningen Verdens Gang och den svenska tidningen Aftonbladet. Undersökningen görs genom att applicera teorierna Dagordningsteorin och Gestaltningsteorin. Vi vill se om det finns några skillnader eller likheter i hur den svenska tidningen Aftonbladet skriver om Sverigedemokraterna en månad efter det senaste riksdagsvalet 2014 och hur den norska tidningen Verdens Gang skriver om den norska motsvarigheten Fremskrittspartiet en månad efter det senaste valet i Norge 2013.   Nyckelord     SD, Sverigedemokraterna, Frp, Fremskrittspartiet, medierapportering, politik, kvällspress   Metod           Kvantitativ innehållsanalys   Material         Artiklar i Aftonbladet tidpunkten 2014-09-15 – 2014-10-14 där orden ”SD” eller ”Sverigedemokraterna” finns med samt artiklar i Verdens Gang tidpunkten 2013-09-10 – 2013-10-09 där orden ”Frp” eller ”Fremskrittspartiet” finns med.

Corrosion presents one of the greatest threats to the durability of reinforced concrete structures, yet it is also one of the least understood components of the design process for most engineers. The nation's infrastructure is rapidly deteriorating due to years of abuse and fatigue. Therefore, several economic and reliable solutions have been developed to repair the existing damage and extend the design life of structures at risk of corrosion. One popular method for protecting concrete structures from corrosion is the use of fiber-reinforced plastic (FRP) composite wraps. The premise is a simple one: placing an impermeable barrier around the surface of the concrete should prevent harmful substances such as chlorides from entering and corroding the imbedded reinforcing steel. However, little is known about the long-term effectiveness in preventing corrosion in reinforced concrete structures. The FRP wrap may in fact prevent the chlorides from passing through the concrete, however, the same principle might cause chlorides to be trapped beneath the surface and accelerate corrosion. In this study, the long-term behavior of laboratory specimens exposed to an aggressive chloride-rich environment were examined. This project was designed to develop a greater understanding of the long-term effects of FRP wrapping in preventing corrosion in reinforced concrete structures. Although TxDOT project 0_1774 involves both rectangular and cylindrical specimens, the focus of this thesis is on the specific impact of FRP wraps on partially wrapped versus unwrapped columns. The specimens included in this study are comprised of a wide range of construction parameters. However, despite the multitude of varying mix designs a noticeable trend has emerged as a result of this research. / text

Despite the importance of molecular recognition in nearly all aspects of protein function, the determinants of specificity for enzyme-substrate and protein-protein interactions are poorly understood. The majority of these complexes involving bacterial luciferase from V. harveyi have yet to be fully characterized. Luciferase catalyzes the reaction of molecular oxygen, FMNH2 and a long-chain aliphatic aldehyde yielding FMN, the corresponding carboxylic acid and blue-green light. In vivo, luciferase is thought to obtain FMNH2 following transfer from a transiently associated oxidoreductase. To identify the oxidoreductase responsible for providing FMNH2 in E. coli, bioluminescence was compared using single gene deletion strains deficient in either a homolog to the endogenous V. harveyi oxidoreductase (Frp) or an oxidoreductase distantly related to luxG from V. fischeri (Fre). Fre is responsible for reducing flavin in vivo but does not physically interact with luciferase. The association between luciferase and the flavin product is also described. Luciferase was crystallized and subjected to soaking with high concentrations of FMN. A model was obtained for luciferase bound to FMN. Using molecular dynamics, models for the enzyme:aldehyde, enzyme:FMNH2, and luciferase bound to several reaction intermediates are presented. Finally, a conserved loop region adjacent to the active center was investigated for the ability to facilitate protein:protein interaction between luciferase and the endogenous Frp oxidoreductase. Following alanine mutagenesis of the charged residues throughout this loop, it appears that the residues targeted by this study are not components of a docking platform but facilitate a lid-gating mechanism of paramount importance for catalytic function.

The use of Fibre Reinforced Polymers (FRP) has grown in popularity in the construction industry. FRP has proven useful in the retrofit of various types of structural elements. It may be used for the strengthening of beams, the seismic upgrade of walls panels, as well as the jacketing of columns to provide confinement. There exist several methods of FRP application for the case of structural retrofits. These include the application of pre-prepared FRP mats, or application of FRP via the wet lay-up process. However, a new technique developed at the University of British Columbia allows for the application of FRP in the form of a spray. Externally bonded Sprayed FRP (SFRP) is known to increase strength and energy absorption capacity of a retrofitted member as well as, or better than, FRP sheets. However, tests have primarily been carried out on concrete members only. An area of interest, into which not much research has been conducted, is the application of SFRP to timber. Timber bridges are extensively used in many parts of the world. Often due to remoteness and practical constraints, it is impossible to apply FRP sheets to retrofit these bridges. SFRP would be a much easier method of FRP application. This study looked at the application of SFRP to Douglas Fir (D.Fir) Beam specimens subjected to 3-Point Flexural Loading only. The specimens were treated with either a water based (Borocol) or oil borne (Creosote) antifungal preservative prior to being sprayed with FRP. Different combinations of adhesives/bonding agents including Hydroxymethylated Resorcinol and Polymeric Isocyanates were used to try to develop a strong bond. When considering using only chemical adhesives to obtain a proper bond between the two constituents of the composite, use of HMR is recommended for timber which is untreated or has been treated with a water borne preservative such as Borocol, while a pMDI adhesive such as AtPrime 2 is recommended for timber treated with an oil borne preservative such as Creosote. For Non Creosoted beams, adhesives did not generate as significant of a strength gain. For Creosoted beams, adhesives may be sufficient to generate significant strength gain when SFRP is applied to a beam. Considering that most structures in use would probably have been treated with a preservative similar to Creosote, in practice, AtPrime 2 or some other some sort of pMDI would probably be the adhesive of choice. Based on the results of the study, it is possible to say that the application of SFRP to retrofit/rehabilitate timber structures shows considerable promise. If a decent bond is achieved between the composite constituents, it is possible to substantially increase the ultimate flexural strength of the member, as well as drastically increase its ductility and energy absorption capacity. It is recommended that further tests be carried out using different types of loading schemes, geometrical configurations of SFRP, other types of anchorage, and development of a proper analytical model before the method is adopted for widespread use.

Fibre reinforced polymer (FRP) materials have emerged as an innovative tool within the civil engineering community for the strengthening and rehabilitation of existing reinforced concrete structures. Research has taken place over the past decade that has demonstrated the benefits of FRPs, and it is evident that there is a need for their usage given the status of the deteriorated North American civil infrastructure. However, in order to increase confidence in the application of these materials in Canada, further information is required to fully understand their behaviour in cold climates. This thesis expands on the previous research that has taken place at Queen’s University, investigating the freeze-thaw behaviour of FRP strengthened reinforced concrete. The research program herein studies the combined effects of freeze-thaw cycling and sustained loading on the flexural performance of 45 small-scale beams strengthened with glass FRP sheets, carbon FRP sheets, or carbon FRP plates. In an attempt to attain failure of the beams due to FRP rupture, the anchorage of the beams was increased and a theoretical model was produced to select the beam design for this failure mode. The model also predicted the performance of the strengthened beams in order to determine appropriate sustained loading levels. After being subjected to 300 freeze-thaw cycles and almost 3 months of sustained loads, the beams were tested to failure. It was found that the beams subjected to combined loads encountered virtually no losses in average ultimate strength. However, the greater inconsistency of the results for these beams relative to the control beams implies that lower guaranteed strengths should be used for design in situations where these conditions are present. / Thesis (Master, Civil Engineering) -- Queen's University, 2008-02-29 14:19:29.954

In recent years, a modified method to strengthen reinforced concrete (RC) structures has emerged involving application of fibre reinforced polymers (FRPs) in the ‘near surface’ of a member. The near surface mounted (NSM) method entails placing a pre-cured FRP bar, rod, strip, or plate, along with an adhesive into a pre-cut groove or slot in the cover of a member. Advantages of the NSM technique over externally bonded (EB) systems include minimal surface preparation and installation time, the ability to anchor the FRP into an adjacent member, superior protection from mechanical and environmental damage, and superior bond properties. Although a number of laboratory studies, field applications, and experimental field projects have employed the NSM FRP strengthening technique, none of these have been performed in a climate where cold environments and freeze-thaw cycling could cause adverse effects. This thesis presents the results of an experimental program to investigate the flexural and bond performance and freeze-thaw durability of a specific NSM carbon/vinylester FRP tape strengthening system through a series of tests on strengthened slab strips and a series of pull-out bond tests. The effects of adhesive type (cementitious or epoxy) and exposure condition (room temperature, freeze-thaw, sustained load, or freeze-thaw under sustained load) are examined. The results indicate no discernable negative impacts on the performance of the grout strengthened members after exposure to freeze-thaw cycles and/or sustained load. The slab strips strengthened with epoxy adhesive displayed minor changes in ultimate load (less than three percent) after exposure to freeze-thaw cycles or a period of sustained load, while the combined effect of freeze-thaw cycles and sustained load produced an average reduction in ultimate load of eight percent. The epoxy adhesive strengthened pull-out bond tests experienced a 27% average drop in ultimate load after 150 freeze-thaw cycles. These results suggest that additional research on the combined effects of sustained load and freeze-thaw cycling are warranted, particularly for NSM strengthening applications using epoxy adhesives. / Thesis (Master, Civil Engineering) -- Queen's University, 2010-04-30 18:11:56.424

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