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. / Master of Science

This diploma thesis presents available FRP software for calculating load bearing capacity of the structures reinforced with FRP and compares them between each other. Furthermore theory and algorithm of my own software is presented here. Load bearing capacity of structures which are reinforced with non-metallic reinforcement and loaded by combination of normal force and bending moment can be solved by my programme. Effects of high temperatures on the concrete structures can be included in the calculation. In the second part of the thesis is calculated load-bearing capacity and deflection of the real beam reinforced with FRP reinforcement and load-bearing capacity of member with FRP reinforcement with effect of elevated temperature. This has been done using my software. Comparison of results from hand calculation and laboratory load-bearing testing is done at the end. This laboratory testing was accomplished by Institute of Concrete and Mansory Structures at our faculty.

Résumé : Le développement des matériaux composites et leur utilisation dans le domaine du génie civil ont fait l’objet d’une recherche extensive sur le renforcement des structures en béton armé. Dans ce contexte, les études sur la compréhension du comportement structural des tubes en matériaux composites (Polymère renforcé en Fibre, PRF) sont indispensables. De fait que les matériaux composites sont innovateurs, cela nous exige de procéder à des investigations expérimentales approfondies pour vérifier les hypothèses et les théories, avant de les produire à échelle industrielle. Ce projet présente une étude expérimentale approfondie sur l’évaluation des propriétés physiques et mécaniques des nouveaux tubes en matériaux composites (PRF), et des tests sur la durabilité du matériau utilisé, et permet d’étudier l’influence de quelques facteurs environnementaux sur ces propriétés mécaniques, ces conditions sont simulées par une immersion prolongée en milieu aqueux et l'exposition à des cycles gel-dégel en milieu humide. Les tubes considérés sont produits par le procédé d’enroulement filamentaire à l’aide des fibres de verre (E) et de résine (Vinyle-Ester). Les expérimentations seront effectuées sur des échantillons normalisés prélevés à partir du tube. Les résultats de cette étude sont d’une importance cruciale pour comprendre le comportement structural (avant et après un vieillissement accéléré) des nouveaux tubes fabriqués entièrement en polymères renforcés de fibres par le procédé de l’enroulement filamentaire. // Abstract : The development of composite materials and their integration in the field of civil engineering has been the subject of extensive research on strengthening reinforced concrete structures. In the perspective of strengthening concrete structures by tubes made of composite materials. In this context, the need for knowledge of the structural behaviour of tubes made from fibre reinforced polymer (FRP) composite materials is prominent. The large using of innovativeFRP required extensive theoretical and experimental investigations. This project presents an experimental study to evaluate both the physical and mechanical properties of FRP-composites tubes, and to investigate the impact of some environmental factors on their mechanical properties. The tubes are produced by a filament winding process using fibre (E)-glass and vinyl-Ester resin. The experiments will be performed on standardized samples of the tube. The main objective of this project is to assess the physical and mechanical properties of laminated FRP composites, and then test the durability of the material used in the manufacture of the tubes. It leads to the study of the effects of some environmental factors on the mechanical properties of material. These conditions occur during an immersion in an aqueous medium and exposure to freeze-thaw cycles. The results of this study are crucial to understand the structural behavior (before and after accelerated aging) of new FRP tubes made by filament winding process.

De fortes illuminations peuvent être dommageables voire même létales pour les organismes photosynthétiques. Une des stratégies utilisées pour se protéger de tels effets délétères consiste à augmenter la dissipation thermique de l’énergie absorbée en excès au niveau des antennes. Chez les cyanobactéries une protéine photo-active, l’Orange Carotenoid Protein (OCP), contrôle ce processus. Une fois photo-activée l’OCP interagit avec le coeur des phycobilisomes (PBs, les antennes collectrices majoritaires chez les cyanobactéries) et déclenche le mécanisme, entrainant à la fois une baisse de l’énergie parvenant aux photosystèmes et une diminution de la fluorescence des PBs. L’énergie absorbée en excès est dissipée sous forme de chaleur. Pour que les PBs regagnent leur pleine capacité de transfert, une autre protéine nommée Fluorescence Recovery Protein (FRP) est requise. La FRP accélère la désactivation de l’OCP. Dans ce manuscrit, je vais présenter ma contribution à la compréhension du mécanisme de photo-protection lié à l’OCP.J’ai continué la caractérisation de la FRP chez Synechocystis PCC 6803, organisme modèle utilisé dans nos études. J’ai montré que la FRP de Synechocystis est plus courte que ce qui est indiqué dans Cyanobase, commençant en fait à la méthionine 26. Mes résultats ont aussi révélé que la photo-protection n’a lieu que lorsque le ratio OCP/FRP est élevé.Le plus grand aboutissement de ma thèse a été la reconstitution in vitro du mécanisme de photo-protection lié à l’OCP en utilisant de l’OCP, de la FRP et des PBs isolés. J’ai montré que la lumière est requise uniquement pour la photo-activation de l’OCP et que l’attachement de l’OCP au PB ne demande aucune illumination. Ce n’est qu’une fois photo-activée que l’OCP peut interagir avec le PB et entrainer la diminution de fluorescence (quenching). En se basant sur les résultats obtenus in vitro nous avons proposé un modèle moléculaire pour le mécanisme de photo-protection lié à l’OCP. Le système de reconstitution in vitro a été utilisé pour évaluer l’importance d’un pont salin conservé (Arg155-Glu244) entre les deux domaines de l’OCP et a révélé que celui-ci stabilise la forme inactive de l’OCP. La photo-activation entraine rupture du pont salin, l’Arg155 étant ensuite impliquée dans l’interaction entre OCP et PB. Le site d’attachement de l’OCP au coeur du PB a aussi été étudié en utilisant le système in vitro. Nos résultats ont montré que les émetteurs terminaux du PB ne sont pas requis et que le site primaire de quenching est un trimère d’allophycocyanine émettant à 660nm. Enfin nous avons étudié les propriétés des états excités du caroténoïde dans l’OCP photo-activée, montrant qu’un de ces états a un caractère de transfert de charge très prononcé et peut avoir un rôle principal dans la dissipation de l’énergie. Nos résultats suggèrent fortement que non seulement l’OCP induit dissipation de l’énergie absorbée sous forme de chaleur mais aussi que l’OCP agit directement comme dissipateur d’énergie. / Strong light can cause damage and be lethal for photosynthetic organisms. An increase of thermal dissipation of excess absorbed energy at the level of photosynthetic antenna is one of the processes protecting against deleterious effects of light. In cyanobacteria, a soluble photoactive carotenoid binding protein, Orange Carotenoid Protein (OCP) mediates this process. The photoactivated OCP by interacting with the core of phycobilisome (PB; the major photosynthetic antenna of cyanobacteria) triggers the photoprotective mechanism, which decreases the energy arriving at the reaction centres and PSII fluorescence. The excess energy is dissipated as harmless heat. To regain full PB capacity in low light intensities, theFluorescence Recovery Protein (FRP) is required. FRP accelerates the deactivation of OCP.In this work, I present my input in the understanding of the mechanism underlying the OCPrelated photoprotection. I further characterized the FRP of Synechocystis PCC6803, the model organism in our studies. I established that the Synechocystis FRP is shorter than what it was proposed in Cyanobase and it begins at Met26. Our results also revealed the great importance of a high OCP to FRP ratio for existence of photoprotection. The most remarkable achievement of this thesis is the in vitro reconstitution of the OCPrelated mechanism using isolated OCP, PB and FRP. I demonstrated that light is only needed for OCP photoactivation but OCP binding to PB is light independent. Only the photoactivated OCP is able to bind the PB and quench all its fluorescence. Based on our in vitro experiments we proposed a molecular model of OCP-related photoprotection. The in vitro reconstituted system was applied to examine the importance of a conserved salt bridge (Arg155-Glu244) between the two domains of OCP and showed that this salt bridge stabilises the inactive form of OCP. During photoactivation this salt bridge is broken and Arg155 is involved in the interaction between the OCP and the PB. The site of OCP binding in the core of a PB wasalso investigated with the in vitro reconstituted system. Our results demonstrated that the terminal energy emitters of the PB are not needed and that the first site of fluorescence quenching is an APC trimer emitting at 660 nm. Finally, we characterised the properties of excited states of the carotenoid in the photoactivated OCP showing that one of these states presents a very pronounced charge transfer character that likely has a principal role in energy dissipation. Our results strongly suggested that the OCP not only induces thermal energy dissipation but also acts as the energy dissipator.

The finite strip method (FSM) is a very efficient numerical method employed for performing the structural analysis of slender structures, such as cable-stayed bridges; the strip discretization of the model allows for the usage of a lower number of degrees of freedom, in comparison with the finite element method (FEM), while, as it will be discussed in the current research, the results obtained from both methods are in relatively good agreement. Moreover, to address the latest developments in the area of smart construction materials used for long-span bridges, the fiber reinforced polymer (FRP) composites were implemented for the bridge deck modeling, as part of a hybrid composite FRP cable-stayed bridge, and an extend laminate integrated finite strip method (LFSM) was applied for estimating the static structural performance of the hybrid composite FRP long-span cable-stayed bridge under several concentrated and uniformly distributed loadings. The free vibrations analysis was conducted for the Kap Shui Mun Cable-stayed Bridge model, and the natural frequencies were compared with the ones obtained from an FE model of the same bridge. One of the advantages of using the integrated finite strip method is that number of vibration modes, which can be included in the dynamic analysis when the effect of a sweeping sinus and a seismic loading are investigated when a conventional FE analysis would fail to converge. The outcomes of this research will set the stage for the hybrid long-span cable-stayed bridges modeling by the laminate integrated finite strip method (LFSM) which is more efficient and straightforward than the finite element analysis, for performing the static, free vibration, time domain, and frequency domain analyses.

Results are presented from the 2021 test run of active fire detection using the Visual Infrared Imaging Radiometer Suite (VIIRS) instrument, that is currently onboard the polar satellites Suomi-NPP and NOAA-20. The test is performed by the Swedish Civil Contingencies Agency and the Swedish Meteorological and Hydrological Institute, in cooperation with local fire departments in Sweden. The aim of this report was to study the impact of clouds on the ability of active fire detection, as well as to identify objects that potentially can cause commission errors in the VIIRS 375 m active fire algorithm (false positive notifications). Also, the study aimed to investigate what may cause omission errors in the algorithm, and to show to what extent the detections can be used to represent the true time development of the wildfire front and burned area. Using a cloudmask and a cloudtype classification product from Nowcasting Satellite Application Facilities (NWC SAF), the impact of clouds was anlalyzed by comparing the cloud data with the obtained fire notifications from the satellites. Active fires and newly burned areas were also studied using Sentinel-2 imagery, specifically the False Color Urban and the Short Wave Infrared (SWIR) RGB composites, as well as images from the 842 nm band, making use of the relatively high spatial resolution as well as the spectral signatures of fire and newly burned vegetation. Detection of active fires occurred in both cloud free and completely cloud covered conditions. How-ever, roughly 70% of the detected vegetation fire pixels were obtained in conditions with 20% clouds or less. / I rapporten presenteras resultat från 2021 års test av satellitdetektering av skogs- och vegetationsbränder, ett test som genomförs av MSB och SMHI i samverkan med kommunala räddningstjänster. De två satelliter som ingår i testet (Suomi-NPP och NOAA-20) går i polära omloppsbanor och är utrustade med instrumentet Visible Infrared Imaging Radiometer Suite (VIIRS). Detta projekt syftade till att undersöka hur molnighet påverkar möjligheten till detektion med satellit, vilka objekt som potentiellt kan ge upphov till falska detektioner samt vad som kan orsaka uteblivna satellitdetektioner. Ytterligare ett mål med rapporten var att genom fallstudier av större bränder undersöka i vilken utsträckning satellitdetektionerna kan användas för att representera brandfrontens utveckling med tiden och brandens faktiska utbredning. Vid studierna av molnighet analyserades en molnmask och en molnklassificeringsprodukt från Nowcasting Satellite Application Facilities (NWC SAF). I utvärderingen användes även data från Sentinel-2 för att studera pågående bränder och avbränd yta, som syns tydligt i RGB-kompositerna False Color Urban och Short Wave Infrared (SWIR) och i 842 nm-bandet, tack vare den relativt höga bildupplösningen och den nyligen avbrända ytans spektralsignatur. Brand detekterades i både molnfria och helt molntäckta förhållanden. Drygt 70 % av detektionerna vid vegetationsbrand kom emellertid i förhållanden med 20 % moln eller mindre.

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.

No description available.

IIn recent years, an investment bottleneck for public infrastructure has accumulated in many industrial countries. Life cycle costing (LCC) is an appropriate management instrument for long-term and sustainable investment. This article addresses the evaluation of high-performance materials (HPM) using LCC to reduce that investment bottleneck. Our research questions are, first, whether and how LCC can be applied to HPM, second, which drivers are primarily influencing the results of a LCC analysis for HPM, and finally, whether HPM are suitable for infrastructure investments, according to economic, social and environmental criteria. We use a comprehensive literature review to analyze existing case studies that apply LCC to HPM. Our review shows that LCC is applied to HPM for structural applications with different levels of detail and quality. The initial results indicate that total life cycle costs for HPM are on average 10% higher. We urge the optimization of the cost structure of HPM to achieve the same level of life cycle costs as conventional construction materials. Moreover, we argue for a more holistic approach that does not ignore sustainability criteria throughout the life cycle of HPM based on the identified drivers of life cycle costs: external costs, an extended life cycle, the discount rate and the expected service life. Indeed, a screened subsample of eight cases is very competitive, with average total life cycle costs for HPM that are 8.4% lower. We share the belief in a more eco-centric approach and, therefore, demand further research into a societal type of LCC that improves the mechanical properties while not ignoring sustainability criteria for new product systems such as HPM.

Despite the superior properties of Fibre Reinforced Polymer (FRP) materials, the use of FRPs in buildings is limited. A key cause of concern for their use in buildings arises from their poor performance in fire occurrences. This thesis presents the results of fire performance of Reinforced Concrete (RC) beams and slabs strengthened with externally bonded FRP sheets. The performance and effectiveness of insulation materials and techniques are also investigated in this thesis. Two full-scale reinforced concrete T-beams and two intermediate-scale slabs were strengthened in flexure with carbon and glass fibre reinforced polymer sheets and insulated with a layer of spray-on material. The T-beams and slabs were then exposed to a standard fire. Fire test results show that fire endurances of more than 4 h can be achieved using an appropriate insulation system. Tests were performed in order to understand the behaviour of FRP concrete bond at high temperatures. An empirical model was then formulated to describe the bond strength deterioration due to temperature rise. Innovative measurement techniques were employed throughout the experiments to measure important observables like strain and temperature. Meanwhile, the effectiveness and practicality of techniques such as Fibre Optic Sensing (FOS) and Particle Image Velocimetry (PIV) for high temperature applications were investigated. A numerical finite-volume heat transfer model was developed to simulate the heat transfer phenomenon. The validity of the numerical model was verified by comparing the results with the results from the fire tests. By using this model, parametric analyses were performed to investigate the effect of different fire scenarios on the performance of the insulated beams. To simulate the structural performance of the T-beams a numerical model which was capable of predicting stresses and strains and deflections of a heated beam was developed. The model is capable of incorporating the effects of axial forces in the response of a restrained beam. This model was verified and used in combination with the thermal model to simulate the deflections of T-beams in fire. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2013-09-17 15:11:16.185