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Mahmoud, Walid Y. "Moment coefficients for ribbed slabs with solid slab strip support." Thesis, University of Leeds, 1989. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.729317.
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Trygstad, Steinar. "Structural Behaviour of Post Tensioned Concrete Structures : Flat Slab. Slabs on Ground." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-114.
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In this investigation strength and structural behaviour of prestressed concrete is studied with one full scale test of one flat slab, 16000 mm x 19000 mm, and three slabs on ground each 4000 mm x 4000 mm with thickness 150 mm. The flat slab was constructed and tested in Aalesund. This slab has nine circular columns as support, each with diameter 450 mm. Thickness of this test slab was 230 mm and there were two spans in each direction, 2 x 9000 mm in x-direction and 2 x 7500 mm in y-direction from centre to centre column. The slab was reinforced with twenty tendons in the middle column strip in y-direction and eight tendons in both outer column strips. In x-direction tendons were distributed with 340 mm distance. There were also ordinary reinforcement bars in the slab. Strain gauges were welded to this reinforcement, which together with the deflection measurements gives a good indication of deformation and strains in the structure.
At a live load of 6.5 kN/m2 shear failure around the central column occurred: The shear capacity calculated after NS 3473 and EuroCode2 was passed with 58 and 69 %, respectively. Time dependent and non-linear FE analyses were performed with the program system DIANA. Although calculated and measured results partly agree well, the test show that this type of structure is complicated to analyse by non-linear FEM.
Prestressed slabs on ground have no tradition in Norway. In this test one reinforced and two prestressed slabs on ground were tested and compared to give a basis for a better solution for slabs on ground. This test was done in the laboratory at Norwegian University of Science and Technology in Trondheim. The first slab is reinforced with 8 mm bars in both directions distributed at a distance of 150 mm in top and bottom. Slab two and three are prestressed with 100 mm2 tendons located in the middle of slab thickness, and distributed at a distance of 630 mm in slab two and 930 mm in slab three. Strain gauges were glued to the reinforcement in slab one and at top and bottom surface of all three slabs. In slab two and three there were four load cells on the tendons.
Each slab were loaded with three different load cases, in the centre of slab, at the edge and finally in the corner. This test shows that stiffness of sub-base is one of the most important parameters when calculating slabs on ground. Deflection and crack load level depends of this parameter. Since the finish of slabs on ground is important, it can be more interesting to find the load level when cracks start, than deflection for the slab. It is shown in this test that crack load level was higher in prestressed slabs than in reinforced slab. There was no crack in the top surface with load in the centre, but strain gauges in the bottom surface indicate that crack starts at a load of 28 kN in the reinforced slab, and 45 kN in the prestressed slabs. Load at the edge give a crack load of 30 kN in reinforced slab, 45 kN and 60 kN in prestressed slabs. The last load case gives crack load of 30 kN in reinforced slab, 107 kN and 75 kN in prestressed slabs. As for the flat slab, FE analyses were performed for all of the three slabs on ground, and analyses shows that a good understanding of parameters like stiffness of sub-base and tension softening model, is needed for correct result of the analyses.
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Wagle, Shyam Sharan <1982>. "SLA Violation Detection Model and SLA Assured Service Brokering (SLaB) in Multi-Cloud Architecture." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/7791/1/WAGLE_ShyamSharan_tesi.pdf.
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Cloud brokering facilitates CSUs to find cloud services according to their requirements. In the current practice, CSUs or Cloud Service Brokers (CSBs) select cloud services according to SLA committed by CSPs in their website. In our observation, it is found that most of the CSPs do not fulfill the service commitment mentioned in the SLA agreement. Verified cloud service performances against their SLA commitment of CSPs provide an additional trust on CSBs to recommend services to the CSUs. In this thesis work, we propose a SLA assured service-brokering framework, which considers both committed and delivered SLA by CSPs in cloud service recommendation to the users.
For the evaluation of the performance of CSPs, two evaluation techniques: Heat Map and IFL are proposed, which include both directly measurable and non-measurable parameters in the performance evaluation CSPs. These two techniques are implemented using real data measured from CSPs. The result shows that Heat Map technique is more transparent and consistent in CSP performance evaluation than IFL technique. In this work, regulatory compliance of the CSPs is also analyzed and visualized in performance heat map table to provide legal status of CSPs. Moreover, missing points in their terms of service and SLA document are analyzed and recommended to add in the contract document. In the revised European GPDR, DPIA is going to be mandatory for all organizations/tools. The decision recommendation tool developed using above mentioned evaluation techniques may cause potential harm to individuals in assessing data from multiple CSPs. So, DPIA is carried out to assess the potential harm/risks to individuals due to our tool and necessary precaution to be taken in the tool to minimize possible data privacy risks. It also analyzes the service pattern and future performance behavior of CSPs to help CSUs in decision making to select appropriate CSP.
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Johnson, Benjamin Crane. "Remotely triggered slab avalanches." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64998.pdf.
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Alzlfawi, Abdullah Hamoud. "EFFECT OF SLAB AND PIER CONNECTION ON TRANSVERSE CRACKING IN STRUCTURAL SLAB BRIDGES." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1525450625325638.
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Hobbs, Michael. "Effects of Slab-Column Interaction in Steel Moment Resisting Frames with Steel-Concrete Composite Floor Slabs." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2014. http://hdl.handle.net/10092/9946.
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Composite construction is widely used worldwide and is undergoing significant technological development. New Zealand is part of this development, with new beam options incorporating multiple unstiffened web openings and new deck profiles supported by extensive testing. However, one area where relatively little research has been undertaken is in the interaction of the composite slab with the seismic resisting system under lateral loading.
In order to provide important new information in this area, a series of full scale beam-column-joint-slab subassemblies were tested at the University of Canterbury. Specimens tested had moment end plate connections and different combinations of deck tray direction, and isolation of the slab from the column. An additional test uses a sliding-hinge type connection to assess the effect of the floor slab in this type of low damage connection.
In these tests the lateral capacity of the seismic resisting system was increased by up to 25% due to the presence of the slab in contact with the column. The increase in capacity is 10% greater for decking running in longitudinal direction than in the transverse direction as a result of a more substantial full depth slab bearing on the column. The floor slabs of the subassemblies with the slab cast against the column all showed a higher level of damage than for those with the isolated column and the post ultimate strength degradation of the subassemblies without special detailing was significant. The subassembly with a section of full depth slab surrounding the column also exhibited a higher capacity but with an improved post ultimate strength degradation. All moment end plate subassemblies sustained drifts of up to 5% without significant strength loss.
The sliding hinge joint showed little signs of damage under testing to 5% drift. Some inelastic deformation of the connection and beams was noted above 5% drift.
Results from both testing and numerical modelling have shown that the current methods used to design these systems are conservative but within 15% of the values observed. Further testing and modelling will be necessary before any meaningful changes can be made to the way in which these systems are designed. Recommendations have been made regarding the placements of shear studs in plastic hinge zones and the provision of slab isolation around beam-column connections.
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Shackleton, Christian John. "Resonators for slab-waveguide lasers." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1387.
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FERNANDES, EDSON FELIPE AMADO. "NEW MODEL FOR THE SLAB STACK SHUFFLING PROBLEM INSIDE THE SLAB YARD OF A HRM." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35415@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROO presente trabalho desenvolve um novo modelo para um problema logístico de remanejamento de placas entre pilhas em um Pátio de Placas de uma Laminação, típico da indústria siderúrgica. Esta abordagem inclui uma nova característica que indica o destino das placas remanejadas. Uma nova metodologia de decisão altera sensivelmente o escopo do problema e traz um novo conceito: o balanço entre a escolha ótima das placas e o possível destino das placas remanejadas, ou seja, deve-se pesar a escolha da placa a ser laminada juntamente com a possibilidade de um bom remanejamento das placas que estão acima da mesma. Esse modelo não linear é linearizado por técnicas de linearização e resolvido através de programação linear inteira. Com isso, o estudo apresenta uma redução no tempo médio de manuseio de placas (TMM) de 5 minutos por placa laminada encontrado na literatura existente, para menos de 4 minutos. Finalmente o modelo proposto incentiva a construção de uma ferramenta de gestão que possa resolver o problema SSS em situações práticas do dia-a-dia através de redução de custo de operação como forma de viabilizar o investimento nesta ferramenta.
This work develops a new model for a typical logistic problem in the steel industry known as slab stack shuffling problem inside a Slab Yard of a Rolling Mill. This new approach includes a new feature that indicates the destination stacks of shuffled slabs. A new decision methodology changes significantly thescope of the problem and introduces a new concept: the balance between optimal choice of the rolled slabs and possible destinations for shuffled slabs which means it must weigh the choice of the slab to be rolled engaged with a low cost shuffle operation for the slabs that are above the chosen slab. This nonlinear model is linearized through specific modeling techniques and solved by integer linear programming. Thus, this work shows a reduction in average handling time (TMM) from 5 minutes per rolled slab found in the literature, to less than 4 minutes. Finally, the proposed model encourages the construction of a management tool that can solve the SSS problem in practical daily situations through operating costs reduction as a payback of investment in this tool.
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Knezevic, Antonijevic Sanja, Lara S. Wagner, Susan L. Beck, Maureen D. Long, George Zandt, and Hernando Tavera. "Effects of change in slab geometry on the mantle flow and slab fabric in Southern Peru." AMER GEOPHYSICAL UNION, 2016. http://hdl.handle.net/10150/622472.
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The effects of complex slab geometries on the surrounding mantle flow field are still poorly understood. Here we combine shear wave velocity structure with Rayleigh wave phase anisotropy to examine these effects in southern Peru, where the slab changes its geometry from steep to flat. To the south, where the slab subducts steeply, we find trench-parallel anisotropy beneath the active volcanic arc that we attribute to the mantle wedge and/or upper portions of the subducting plate. Farther north, beneath the easternmost corner of the flat slab, we observe a pronounced low-velocity anomaly. This anomaly is caused either by the presence of volatiles and/or flux melting that could result from southward directed, volatile-rich subslab mantle flow or by increased temperature and/or decompression melting due to small-scale vertical flow. We also find evidence for mantle flow through the tear north of the subducting Nazca Ridge. Finally, we observe anisotropy patterns associated with the fast velocity anomalies that reveal along strike variations in the slab's internal deformation. The change in slab geometry from steep to flat contorts the subducting plate south of the Nazca Ridge causing an alteration of the slab petrofabric. In contrast, the torn slab to the north still preserves the primary (fossilized) petrofabric first established shortly after plate formation.
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Brush, Natalie Camille. "Connection of modular steel beam precast slab units with cast-in-place closure pour slabs." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1356.
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Jointless bridges are advantageous in removing mechanical joints which are a known cause of bridge deterioration. Elimination of joints provides a smoother riding surface and removes the possibility of de-icing salts penetrating the deck and corroding the deck reinforcing and underlying bridge superstructure. Jointless bridges are traditionally constructed by monolithically casting the entire bridge deck on beams after they have been erected. However, this process requires extensive in-field formwork and lengthy traffic closures. The Texas Department of Transportation proposes a new method of constructing jointless bridges using prefabricated girder-and-deck units connected on-site with cast-in-place closure pours. This new system will expedite construction and reduce disturbances to the traveling public.
The objective of this experimental study was to investigate the behavior of the cast-in-place closure pour slab and to determine if it responds to wheel loads in the same way as a traditional monolithic continuous deck. The effects of the cold joints and discontinuous steel details are the focus of the research work.
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Kareliusson, Filip, and Thomas Lipecki. "Bjälklag i Betong är billigare än Korslimmat trä : en jämförelse mellan bjälklagskonstruktioner." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-31522.
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Byggnadstaktenav flerbostadshus i Sverige ligger på en hög nivå och ökar. Detta medför kravpå en snabb byggprocess. En lösning för att snabba på byggprocessen äranvändandet av prefabricerade delar. Författarnas uppgift, i samarbete med WSPSverige AB, är att utveckla ett hjälpmedel för konstruktörer som jämför fyraolika bjälklag, varav ett i korslimmat trä, två prefabricerade betongelementoch en platsgjuten konstruktion. Målet är att framställa en tabell som beaktarfaktorer som påverkar valet av stomsystem och som presenterar vilket avbjälklagen som är mest kostnadseffektivt. Rapporten sammanställdes under 10veckor och avgränsades till bjälklag i flerbostadshus upplagda på två stöd somuppfyller relevanta krav för dimensionering, beaktar torktid med fastaförutsättningar, leveranstid avseende produktionstid hos de prefabriceradeelementen och miljöpåverkan avseende CO2-ekvivalenta utsläpp iproduktionsskedet. Studiens resultat grundar sig på litteraturstudier ochintervjuer, kalkylhjälpmedel och beräkningsprogram som är vanliga i branschen.Resultatet visar att: · trä genererar lägst koldioxidutsläpp avbjälklagsalternativen · betong är, ur ett brand- och ljudperspektiv, detlämpligaste materialet · korslimmade träbjälklaget får den högsta byggnadshöjdenoch den högsta kostnaden per kvadratmeter · håldäcksbjälklag har den kortaste leveranstiden · det slakarmerade plattbärlag samt det platsgjutnabetongbjälklaget har längst torktid · den platsgjutna bjälklagskonstruktionen är detmest kostnadseffektiva bjälklaget av de fyra som har jämförts.The building pace of multi apartment houses in Sweden is at a high leveland is increasing. This induces demands of a quick building process. Onesolution to quicken the building process is the use of prefabricated elements.The authors’ task, in collaboration with WSP Sverige AB, is to develop anaiding tool for engineers who compare different slabs, one cross laminatedwood, two precast concrete components and one construction cast in-place. Thegoal is to produce a table that considers factors that affects the choice ofstructure and presents which of the slabs that is most cost effective. Thepaper was compiled over a period of 10 weeks and limited to slabs inmulti-apartment buildings supported on two sides that meet relevantrequirements for dimensioning, consider hydration time with set conditions,delivery time regarding production time for the precast components andenvironmental effects considering CO2-equivalent emissions in the productionstage. The results of the study are founded on literature and interviews,calculation-aids and computational programs that are common in the industry.The outcome shows that: · woodgenerates the least amount of carbondioxide emissions of the slab alternatives · concrete is, from a fire- and acoustic perspective, the most suitable material · thecross laminated slab renders the highest cross-section and the highest cost persquare meter · hollow core slabs has the shortest delivery time · theconventionally reinforced precast slabs and the in-situ cast floor slabs havethe longest hydration times · thein situ slab is the most cost effective slab of the four that have beencompared.
Betyg 170707, H14.
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Gorczyk, Weronika. "Dynamic processes above the subducting slab /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17543.
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Scales, Christine. "Magneto-plasmons in optical slab waveguides." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26765.
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The effect of an externally applied magnetic field on the propagation characteristics of a plasmon-polariton wave supported by an infinitely wide thin metal waveguide was investigated. In order to do so, the dispersion relation was derived, from Maxwell's equations, enabling accurate modelling of the situation of interest. The general dispersion relation, including the constraint equation, for magneto-plasmons was derived in general, and then, specifically for a magnetic field applied along three orthogonal cartesian axes. The losses in the metal were included in the dispersion equation so that a better understanding of the influence of an externally applied magnetic field may be provided.
The dispersion relation is used as the basis of a software model of magneto-plasmons in thin metal films. This model is validated against specific cases in the literature with and without an externally applied magnetic field. The specific formulations in the literature were deemed to be incorrect, and have been corrected and the results have been interpreted. The model is then used to simulate thin gold films bounded by silicon dioxide at an infrared wavelength. The modelling results include the effect of the externally applied magnetic field on the propagation constant and the corresponding field components for all three Cartesian orientations of externally applied magnetic field. The results from these simulations are presented and interpreted. (Abstract shortened by UMI.)
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Lee, Taeyoung. "Improved slab method for axisymmetric forging." Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1178221157.
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Khorshidahmad, Amin. "Controlling light with slab photonic crystal." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104667.
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This thesis presents novel designs and schemes for wavelength demultiplexing, frequency conversion and multi-wavelength generation applications, achieved by engineering the band structure and dynamic control of the dispersion in planar photonic crystal (PhC) platform. The composite superprism demultiplexer, whereby simultaneous diffraction compensation and angular channel separation considerably reduces the footprint required in conventional superprisms, is proposed. A design model is developed and applied to optimize and analyze the scaling properties of the demultiplexer. Expanding the bandwidth of the conventional superprism in a compact stratified hetero-lattice operating in reflective scheme is also investigated. Increasing the adiabatically achievable frequency shift by the structural change induced via tuning the slab refractive index of a nested cavity is shown. Wavelength conversion using the proposed dynamically reconfigurable nested resonators is further studied. In this scheme, ultrafast modulation of the refractive index, e.g. via induced free carriers, transforms the photons stored within the original cavity into the distinct set of eigenmodes of a dynamically formed resonator. As a result, an arbitrary frequency shift, determined by the spectral separation of the resonances of the initial and the tuned cavities, is achievable provided a fast enough tuning. This scheme may also eliminate the adiabatic frequency conversion that normally co-exists with intermodal transitions in a static cavity. Optical comb sources with tunable spectrum by dynamically controlling the reconfiguration, tailoring the dispersion and utilizing the symmetry of the mode profiles in nested resonators is also proposed and numerically demonstrated.Cette thèse présente des concepts et plans originaux pour des applications en démultiplexage de longueur d'onde, conversion de fréquence et génération de multi-longueur d'onde, obtenue par la conception de la structure de bande et le contrôle dynamique de la dispersion de la plate-forme de cristaux photoniques (CPh) planaires.Un démultiplexeur superprisme composite, par lequel la compensation de la diffraction ainsi que la séparation angulaire des canaux réduit considérablement l'encombrement requis par les superprismes classiques, est proposé. Un modèle de conception est développé et appliqué afin d'optimiser et d'analyser les propriétés de mise à l'échelle du démultiplexeur. L'élargissement de la bande passante du superprisme classique dans une exploitation compacte hétéro-réseau stratifiée dans un schéma de réflexion est également étudiée. L'augmentation du décalage de fréquence adiabatique réalisable par le changement structurel qui est induit par la modification de l'indice de réfraction de la dalle dans une cavité imbriquée est présenté. De plus, la conversion de longueur d'onde grâce aux résonateurs imbriqués et dynamiquement reconfigurables qui sont proposés dans cette thèse est étudiée. Dans ce schéma, la modulation ultra-rapide de l'indice de réfraction, par exemple via des porteurs libres induits, transforme les photons accumulés dans la cavité d'origine en un ensemble distinct de modes propres d'un résonateur configuré dynamiquement. En conséquence, un décalage en fréquence arbitraire, déterminé par la séparation spectrale des résonances de la cavité initiale et celles du résonateur accordé, est réalisable à condition qu'un réglage soit fait rapidement. Ce système peut aussi éliminer la conversion de fréquence adiabatique qui accompagne normalement la transition entre les modes dans une cavité statique. La conception de sources peigne de fréquences optiques à spectres accordables par le contrôle dynamique de la configuration, l'adaptation de la dispersion et l'utilisation de la symétrie des profils des modes dans les résonateurs imbriqués est également proposée et démontrée numériquement.
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Cameron, Andrew Alexander. "High pressure slab waveguide CO2 lasers." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/1223.
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Northard, Sarah Jane. "Deformation of the Tonga subducting slab." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264511.
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Fyffe, Blair. "Mechanisms of snow slab avalanche release." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/13864.
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Avalanche release is a brittle process meaning that fracture toughness rather than shear strength may be the fundamental parameter controlling slope stability. The results of a series of experiments to measure the fracture toughness of soft slab are reported. Snow was found to be toughest in mode I. The mode II and mode III values are approximately equal, and about 70% of the mode I. The mode II and mode III values are approximately equal, and about 70% of the mode I value. The fracture toughness of a weak layer was found to be about 1 kPa m1/2. In addition to shear strength and/or fracture toughness, the coefficient of basal friction between the slab and the substrate is of obvious importance to slab avalanche release. Various sources suggest that the coefficient of friction for dry slab is quite variable, but a value of about 0.6 seems quite typical. Incorporating this and other typical snow parameters into shear band models gives a critical crack size of the order of ten metres. This is much too large to be produced by a skier. We discuss two alternative release mechanisms for skier triggered avalanches. The first of these is the interaction between local skier damage and the complex pattern of internal shear cracks assumed to lead to natural failure. The other mechanism is the whumpf of flexural wave, which is caused by compressive collapse and subsequent loss of shear strength of the weak layer. The relative importance of these two processes combined with highly variable basal friction can explain the wide variety of different behaviour associated with skier triggered avalanches. Examples of such behaviour are: a skier triggering a well tracked slope, slopes that whumpf (and sometimes can be felt to move and crack) but do not avalanche, and remotely triggered avalanches.
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Piotter, Jason Matthew. "Longitudinal Slab Splitting in Composite Girders." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/31765.
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Longitudinal slab splitting in composite hot rolled girders and joist girders was investigated. Two different type of framing configurations were studied with two tests conducted per configuration. The framing configurations were designated as either flush-framed or haunched, which describes the framing of the joists into the joist girders or H-shape. Each floor system consisted of at least one exterior or spandrel joist girder, one interior joist girder, and in three of the four tests, an exterior or spandrel H-shape. The nominal lengths of the girders were 30 ft 4 in. with a centerline spacing of 7 ft for the flush-framed tests and 6 ft 9 in. for the haunch tests. Varying amounts of transverse reinforcement were used in the slab over each girder. Shear connectors were all 0.75 in. diameter headed shear studs of varying lengths. The results of these tests were used to determine the minimum amount of transverse reinforcement required to prevent longitudinal splitting from controlling the strength of the section. A comparative analytical study was performed to generate a design procedure for determining the appropriate amount of transverse reinforcement. This consisted of adapting existing procedures in reinforced concrete for similar shear problems and generating alternative procedures based on existing research for composite construction. Results from these methods were then calibrated against experimental data obtained in this study.Master of Science
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Zanjir, Ahmad Mohamed Rifat. "Vulnerability of Buildings with Flat Plates and Flat Slabs to Progressive Collapse." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22824.
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The investigation of progressive collapse of buildings has been of special interests during the last decade. The aim of this study is to assess the influence of selected design parameters on the vulnerability of structures with flat plates or flat slabs to progressive collapse triggered by the severe damage or failure of a column as a result of accidental or maliciously intended terrorist activity. The variables of frames with two-way slab systems investigated include: the number of stories in buildings (low-, medium- and high-rise buildings), span ratio (the ratio of span lengths in two orthogonal directions), span length for square panels, as well as the effect of having flat plates compared to flat slabs detailed either as ordinary gravity load carrying systems or by following the seismic detailing requirements of the Canadian practice as per CSA A23.3-04.
The linear-elastic static analysis method, outlined in the General Services Administration (GSA) guidelines of the US, was employed to conduct a parametric investigation to assess the significance of the design variables considered on progressive collapse potentials of buildings. This involved the computation of demand/capacity ratios (DCR) Higher DCRs were obtained for buildings with increased number of stories and span ratios, while the change in span lengths did not show a clear trend. Also, flat slabs were less vulnerable, and experienced smaller DCRs, than flat plates. Buildings detailed according to the seismic provisions of CSA A23.3-04 were less vulnerable than those detailed without these provisions. However, both slabs with non-seismic and seismic detailing required improvements in terms of the percentage of top and bottom reinforcement and bar lengths, depending on the slab type and the design parameters considered.
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Tarek, Asmaa, and Zhir Farhad. "Implementering av VBS system i Sverige." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-84294.
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Betong är idag ett av de material som vi använder mest i byggbranschen och det har sinaföljder. Mer än 50 % av energiutsläppen från byggplatsen kommer från cementtillverkningen.Voided biaxial slab eller VBS är en revolutionerande teknik där man gjuter in plastbollar ibetongen tillsammans med armeringen. Arbetstiden samt torktiden kortas ned samtidigt somvi bevarar hållfastheten och dess funktionalitet. I den här rapporten kommer vi titta närmarepå VBS teknik och jämföra det med konventionell betongplatta och se om tekniken är lämpligför att implementeras i Sverige.Vi har använt oss av en kvalitativ metod i form av källanalys från internet och tryckta källor.Även en komparativ metod i de fallen vi har hittat information från mer än en källa.Rapporten kommer enbart fokusera på betongplattor och våningsavskiljande bjälklag. VBSanvänds i horisontella plan endast. Tak och väggar är därför uteslutna. Tekniken kommerpresenteras i form av viktiga aspekter för dess överlevnad i den svenska marknaden såsomekonomi, strukturella fördelar och hållbarhet.Resultatet visar att VBS rent ekonomiskt nästan bara är positivt jämfört med denkonventionella betongplattan som endast består av armerad betong. Konstruktionsmässigt ärVBS ett konkurrenskraftigt alternativ till armerad betong. Böjhållfastheten är detsamma somarmerad betong. Andra bra positiva aspekter är miljövänligheten, arbetsmiljömässigt,energikonsumtion och värmeisolering.De mindre bra egenskaperna är sämre prestanda i skjuvmotstånd, brandmotstånd ochljudisolering.VBS kan implementeras i Sverige men för att plast ska introduceras i en så pass stor skala såbehövs en infrastruktur. Den bör tillgodose hållbart produktion av Bubbledeck och separeramaterialen vid rivning. Tekniken medför stora fördelar men trots det kan företagen få svårt attmotivera sig till att bygga med VBS när betong är så lättillgängligt och varit med så länge.Concrete is today one of the materials we use most in the construction industry and it has itsconsequences. More than 50% of the energy emissions from the construction site come fromcement production. Voided biaxial slab or VBS is a revolutionary technique in which plasticballs are cast into the concrete together with the reinforcement. The working time and thedrying time are reduced while maintaining the strength and its functionality. In this report, wewill take a closer look at VBS technology and compare it with conventional concrete slab andsee if the technology is suitable for implementation in Sweden.We have used a qualitative method in the form of source analysis from the Internet andprinted sources. Also a comparative method in cases where we have found information frommore than one source.The report will focus solely on concrete slabs and floor separating flooring. VBS is used inhorizontal planes only. Roofs and walls are therefore excluded. The technology will bepresented in the form of important aspects for its survival in the Swedish market such aseconomy, structural benefits and sustainability.The result shows that VBS is financially almost only positive compared to the conventionalconcrete slab, which consists only of reinforced concrete. In terms of design, VBS is acompetitive alternative to reinforced concrete. The flexural strength is the same as reinforcedconcrete. Other good positive aspects are environmental friendliness, work environment,energy consumption and heat insulation.The less good features are poor performance in shear resistance, fire resistance and soundinsulation.VBS can be implemented in Sweden but for plastic to be introduced on such a large scale, aninfrastructure is needed. It should meet the sustainable production of Bubbledeck and separatethe materials during demolition. The technology brings great benefits, but despite this,companies can find it difficult to motivate them to build with VBS when concrete is so easilyaccessible and has been around for so long.
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Michas, Georgios. "Slab track systems for high-speed railways." Thesis, KTH, Väg- och banteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96507.
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In the last 40 years an increase in train speed and axle load around the world and other challenges in the conventional ballasted track system gave birth to ballastless railway track system. This study examines in depth the various slab track systems that are being used today. Their design characteristics as well as the various requirements for efficient use are thoroughly explained. At least 34 different ballastless systems have been recorded in many railway networks throughout the world. The most significant slab track systems are analysed in detail and compared. Slab track designs have significant advantages comparing to ballasted tracks. The most significant are the high stability of the track, the almost non-existent need for maintenance, the long life cycle (60 years) and the reduced weight and height of the track. Their disadvantages against the ballasted tracks are mainly summarized in their higher construction costs. The Finite Element package ABAQUS/CAE is used to model a 3-D slab track design under static traffic loading. The results suggest that slab tracks have profoundly better stability and durability comparing to ballasted tracks mainly due to their higher stiffness and strength. The author underlines the need for further studies to undoubtedly prove the claimed advantages of slab track systems as well as to improve the costs associated with construction.
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Shao, Xiao-yun. "Punching shear strength of reinforced concrete slab." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/10727.
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This thesis presents the results of punching shear tests performed on a 2 x 2 bay continuous slab with/and without supplementary supports. On the basis of these tests, the code method of calculating the ultimate strength of interior, edge and corner column connections of flat slab were investigated. The thickness of the specimen was 140 mm and the spans length were 2743 mm. The ACI 318-89, BS 8110-85 and CEB-FIP 90 Codes were critically reviewed by comparing with the experiment results and results from the literature. It was found that in general the Code predictions are reasonable but for corner column connections the ACI Code over-estimates the ultimate shear capacity of the slab and BS 8110-85 requirements for edge and corner column connections are simplistic. The experimental results show that the supplementary supports can increase the ultimate punching shear capacity when the supports are properly located.
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Bakhtazad, Aref. "Slab photonic crystal demultiplexers : analysis and design." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102955.
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The exploitation of the superprism phenomenon for optical demultiplexing using a slab photonic crystal on the silicon on insulator platform is the main subject of this thesis. The S-vector and k-vector superprisms are considered. Design equations for the S-vector superprism demultiplexer which fully take into account the nonlinear spectral dependence of beam propagation and dispersion are introduced. This allows wide-band coarse wavelength division multiplexing (CWDM) demultiplexers to be designed. Selecting minimum prism area as a metric, the best photonic crystal lattice, design parameters and prism geometry is sought. A full 3-D modeling approach using the plane wave expansion method is employed to ensure the practicality of the design. We show that the slab 1-D photonic crystal can provide the smallest superprism. Based on our result, an area of 1367 mum2 is sufficient to resolve 4 standard CWDM channels (20nm channel spacing). We extend this approach by proposing a stratified photonic crystal which has 5 times less area for an 8 channel CWDM design.We then propose the first fully integrated k-vector superprism layout. Design rules and equations are presented and we use these to obtain the design parameters that result in a minimum prism area. We show that an optimized 1-D photonic crystal k-vector superprism with the area of less than 0.1 mm2 is sufficient to resolve 32 standard dense wavelength division multiplexing (DWDM) channels (100GHz channel spacing). The resulting chip size is approximately 4.5 times less than an equivalent etched grating demultiplexer.
We also demonstrate that fast lenses can be made using slab 1-D photonic crystal with an periodicity.
We introduce an analytical approximation technique for slab 1-D photonic crystals based on the weighted index method. The variational nature of the method leads to acceptable results for moderate refractive index contrast materials. The method can also be extended to 2-D cases and to nonlinear systems.
The plane wave expansion (PWE) method and field matching have been combined to obtain a new method which is capable of obtaining all types of modes including the leaky modes of slab 1-D photonic crystals. The method requires fewer plane waves than the conventional PWE method but provides a better approximation. We compare our results with an accurate finite element method as a benchmark.
A report of our first attempt for the fabrication, post-possessing and optical characterization of the proposed k-vector superprism demultiplexer is also presented. We recommend the development of a cladding, and more accurate fabrication procedures for future investigations.
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Saucedo, Francisco Javier Villarreal. "RF excited carbon monoxide slab waveguide lasers." Thesis, Heriot-Watt University, 1996. http://hdl.handle.net/10399/1222.
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TAKEY, TADEU HIROAKI. "COLD FORMED SLAB SYSTEMS FOR BUILDING CONSTRUCTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2001. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2421@1.
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Este trabalho apresenta um estudo de um novo sistema de
laje mista com o uso de perfis metálicos de chapa dobrada e
isopor seqüencialmente dispostos lado a lado e preenchidos
com concreto de armado. A principal motivação para este
estudo foi o desenvolvimento de um eficiente sistema de
laje fácil e rápida de ser construído, e que
fosse econômica. O sistema de laje desenvolvido maximiza o
espaço livre útil da construção, eliminando a necessidade
de formas e escoras tendo assim como conseqüência direta a
minimização das perdas construtivas. Os resultados obtidos
indicaram que os custos do novo sistema de laje são
equivalentes aos outros métodos de construção de lajes, mas
que outras características como o tempo e as perdas
economizadas na fase construtiva viabilizam a utilização do
novo sistema.O trabalho foi consta de três fases
principais: primeiramente uma otimização do estudo dos
perfis de chapa dobrada foi conduzida analisando as suas
características estáticas e dinâmicas para o sistema de
laje. Variáveis como peso, altura, espessura,tensão de
escoamento, vão máximo, carga suportada por vão e por
espessura da chapa metálica, momento máximo, capacidade de
carga, minimização dos custos de fabricação e
possibilidades de uso de vãos múltiplos foram validados.
Quando a seção do perfil metálico estava definida e
otimizada, foi estabelecido um estudo com uma série de 5
(cinco) testes em escala real. O propósito principal dos
testes foi obter os estados limites último da seção do
perfil adotado associado ao sistema de laje para validação
do sistema estrutural. Os testes avaliaram a real
aderência entre concreto e perfil metálico e sua influência
no estado limite último de flexão, cisalhamento e
deslizamento. Outra solução além da aderência química
natural do concreto com o perfil metálico envolveram o uso
de parafusos auto atarrachantes como conectores de
cisalhamento. A fase final compreendeu a comparação dos
resultados experimentais com as normas de aço para
averiguar a validade dos resultados do sistema de laje
mista.This work presents an investigation of an innovative composite slab system made of a steel deck and a styrofoam plate, side by side, filled with reinforced concrete. The objective of the present study was the development of an efficient composite slab system that is easy to manufacture, erect and also economic.The investigation started with a parametric design study of the steel deck profile.When an optimum steel deck profile was established the investigation proceeded with a series of full-scale- experiments. The tests enable the establishment of the ultimate and serviceability limit states associated with the investigated system.Another aim of the experiments was to investigate the concrete versus steel deck connection. Solutions using only the natural concrete versus steel adherence and others utilising shear connectors made of self-drilling bolts in the steel deck were considered. Finally current steel design codes were used to compare the experimental results and access the accuracy of the composite slab system In this paper a composite slab system developed for low-cost building construction is presented. Results and conclusions from a theoretical and experimental study were summarized below the work. Finally these composite slab systems can be implemented in large scale construction, just by the development of portable rolling equipment that can produce very long and continuous profiles, as required by the construction teamwork.
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Menez, Martin Herve. "Efficiency of a fabric formed concrete slab." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104241.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2016.Cataloged from PDF version of thesis. Page 123 blank.
Includes bibliographical references (pages 121-122).
The built environment is responsible for approximately 50% of the carbon emissions on the planet. Therefore, it is of major importance to reduce the carbon footprint of our structures to better preserve our environment for future generations. Furthermore, studies demonstrate that flooring systems can be responsible for 70% of material consumption in high rise buildings, and about the same proportion of embodied carbon energy. Based on these considerations, this thesis suggests a new form of concrete slab and quantifies its efficiency in terms of material, carbon energy and cost savings compared to a traditional reinforced concrete flooring system. The proposed form of concrete slab is constructed using fabric formwork. It provides the flexibility and ease of construction needed to build such a low-volume structural shape. After establishing that this slab can be about 50% lighter than a traditional reinforced concrete slab, the thesis models and quantifies the savings in other parts of the structure and shows that the embodied carbon footprint of the entire building can be reduced by approximately 50%. Keywords: Concrete slab - Compression only - Fabric-formworks - Carbon energy
by Martin Herve Menez.
M. Eng.
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Midkiff, Corey J. "Plastic voided slab systems: applications and design." Kansas State University, 2013. http://hdl.handle.net/2097/16874.
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Master of ScienceDepartment of Architectural Engineering
Kimberly Waggle Kramer
Reinforced concrete slabs are one of the most common components in modern building construction. Reinforced concrete slabs with plastic voids slabs are a new and innovative type of structural, concrete slab system developed to allow for lighter self-weight of the structure while maintaining similar load carrying capacity of a solid slab. Plastic voided slabs are capable of reducing the amount of concrete necessary to construct a building by 30 percent or more. This reduction can be beneficial in terms of financial savings as well as building performance. This report examines a two-way, reinforced concrete slab with plastic voids construction in comparison to traditional flat plate reinforced concrete slab construction. The design process for plastic voided slabs is directly compared with traditional two-way flat plate reinforced concrete slabs through a design comparison of typical bays of 20’ by 20’ (6m by 6m), 25’ by 25’ (7.6m by 7.6m), 30’ by 30’ (9m by 9m) and 35’ by 35’ (10.7m by 10.7m). The traditional slab design process follows the ACI 318-11 Building Code Requirements for Structural Concrete chapter 13 Direct Design Method, while the plastic voided slab design process is modified from the BubbleDeck Design Guide for compliance with BCA using AS3600 and EC2. Sizes of traditional slab bays are compared to sizes of plastic voided slab bays. Results of the comparison study are presented.
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Baah, Prince. "Cracking Behavior of Structural Slab Bridge Decks." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1417539467.
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Sampaio, Soares Luis Fernando. "Influence of slab continuity on punching resistance." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/48011.
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This research addresses the design of reinforced concrete flat slabs for punching shear. Flat slabs are two way spanning slabs without downstand beams that are directly supported by columns. The thickness of flat slabs is typically governed by considerations of either deflection control or punching shear for which there is still no widely accepted theoretical treatment. The research seeks to develop a better understanding of the effects of in-plane restraint and flexural continuity on the punching resistance of flat slabs. The overriding aim is to determine whether flexural continuity is sufficient to explain the satisfactory performance of existing flat slabs which appear punching shear deficient when assessed against test data from isolated punching shear specimens. The influence of slab continuity on punching resistance is assessed through analysis of test data, nonlinear finite element analysis (NLFEA) and fib MC2010 Level of Approximation (LoA) IV which is based on the Critical Shear Crack Theory (CSCT) of Muttoni. The CSCT relates shear resistance to the width of the so-called ‘critical shear crack’ which depends on slab rotation. MC2010 has four LoA of which I to III are intended for design. Punching resistance is normally determined from tests on isolated slab-column specimens which are intended to simulate behaviour within the elastic line of contraflexure for radial moments, although the benefits of continuity on punching shear strength is well known. MC2010 LoA IV, which uses nonlinear finite element analysis to determine the slab rotation, is used to investigate and develop a better understanding of the influence of continuity on the punching shear resistance of flat slabs at edge and internal columns. The FE model is calibrated against relevant test data from both isolated and continuous specimens. Parametric studies are presented which show the superseded UK design code BS8110 to require significantly less punching shear reinforcement than EC2 (2004) and MC2010 LoA II which give reasonable strength predictions for isolated internal column punching specimens. Despite this, slabs designed to BS8110 have performed satisfactorily for many years. MC2010 LoA IV is used to show that punching resistance at internal columns can be increased significantly by restraint from the surrounding slab. The increase in punching resistance due to continuity is shown to be sufficient to explain the satisfactory performance of flat slabs designed to BS8110 at internal columns. However, the strength increase is variable and, in the case of uniformly loaded slabs, already largely included in BS8110 and EC2. The research also considers the influence of slab continuity on punching resistance at edge columns. Parametric studies are developed to examine the influence of shear force eccentricity, flexural reinforcement distribution between support and span, and modelling assumptions on the punching resistance of flat slabs at edge columns. Relating the punching resistance at edge columns to the elastic unbalanced moment as done in MC2010 LoA II and III is shown to be overly conservative for continuous slabs. The ACI 318 and EC2 practice of making the design punching resistance independent of the unbalanced moment is reviewed and shown to be reasonable particularly for continuous slabs. MC2010 LoA IV is shown to be a powerful tool for assessment, however the predictions for the method are very sensitive to the modelling assumptions and boundary conditions.
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Bengtsson, Pär, and Johan Wallin. "Analysis of a Prefabricated Concrete Skew Angle Slab Bridge." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-81146.
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Prefabricated concrete elements are widely used in the construction industry today. With advantages such as time savings, increased safety at the construction site and minimized material usage, prefab becomes a major challenger to the traditional on-site casting construction method. However, constructing a bridge in concrete still presents challenges when using prefab as a construction method. Hence, more research in the area is needed. This master thesis has been studying the behavior of a prefabricated skew angle slab and the connection between the slab and wall elements of a bridge. The study was conducted using a finite element software, where three 3D-models of skew angle slabs were created. The three models had different skew angles (0, 15 and 30 degrees) and crossed the same path. The models could represent both the slab and the slab-wall connection. The finite element analysis showed that slabs with angles up to 15 degrees could be designed as a straight bridge. However, when the skew angle increases to 30 degrees, the behavior of the slab and connection changes significantly. Furthermore, the results show that a stress concentration occurs in the obtuse corner and that the stress increases when the skew angle increases. Moreover, there is a slight uplift in the acute corner when the skew angle increases to 30 degrees.
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Kostet, Daniel. "Railway bridges with floating slab track systems : Numerical modelling of rail stresses - Dependence on properties of floating slab mats." Thesis, Luleå tekniska universitet, Byggkonstruktion och -produktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67297.
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The increased use of continuously welded rails in the railway systems makes it necessary to increase the control of the rail stresses to avoid instability and damages of the rails. Large stresses are especially prone to appear at discontinuities in the railway systems, such as bridges, due to the interaction between the track and the bridge. The interaction leads to increased horizontal forces in the rails due to the changed stiffness between the embankment and the bridge, temperature variations, bending of the bridge structure because of vertical traffic loads and braking and traction forces. If the compressive rail stresses become too high it is necessary to use costly and maintenance-requiring devices such as rail expansion joints and other rail expansion devices. These devices increase the railway systems life cycle cost and should if possible be avoided. The use of non-ballasted track on high-speed railways, tramways and subways, has increased since this kind of track requires less maintenance and according to some investigations have a lower life cycle cost compared to ballasted track. The non-ballasted track is usually made of a track slab to which the rails are connected through fastenings. The track slab is connected to the bridge structure and held in place by shear keys. When non-ballasted tracks are used in populated areas it is sometimes necessary to introduce some vibration and noise damping solution. One of the possible solutions is to introduce a floating slab mat (elastic mat) under the track slab on the bridge. The influence of the floating slab mats properties on the rail stresses is investigated in this degree project. The investigation was performed through a numerical modelling of two railway bridges using the finite element software SOFiSTiK. The results from the investigation showed that there was a small reduction of the compressive rail stresses by approximately 3 – 7% (depending on the stiffness of the elastic support, load positions and the properties of the mat) when a mat was installed under the track slab. The results from the investigation also showed that there was a small reduction (up to approximately 1 %) of the compressive stresses in the rail when the thickness of the mat was increased, and the stiffness of the mat was reduced. This reduction of the compressive stresses is assumed to be caused by the mat being mounted on the sides of the shear keys. The lower stiffness of the mat allows the track slab and the bridge deck to move more freely parallel to each other in the horizontal direction. This leads to a decrease of the stresses in the rail due to a lower interaction between the track and the bridge. It was also shown that the rail stresses increased if the friction between the slab mat and the bridge deck was considered. This is because of an increase of the interaction between the track and the bridge due to the mats horizontal stiffness.Den ökade användningen av kontinuerligt svetsade räler i järnvägsnäten i världen leder till en ökad kontroll av rälsspänningarna för att undvika instabilitet och skador på rälsen. Särskilt vid en diskontinuit i järnvägssystemet, som vid broar, kan stora tillskottspänningar i rälsen uppstå till följd av interaktionen mellan spår och bro. Interaktion leder till ökade horisontella krafter som verkar på rälsen och beror på den förändrade styvheten mellan järnvägsbank och bro, temperaturvariationer, nedböjning av bron på grund av vertikala trafiklaster samt broms- och accelerationskrafter. Om spänningarna i rälsen blir för stora behöver kostsamma och underhållskrävande dilatationsfogar införas. Dessa dilatationsfogar ökar järnvägssystemets livscykelkostnad och är något som ska undvikas att införas i den mån det är möjligt. Användningen av ballastfritt spår för höghastighetsjärnvägar, spårvägar och tunnelbanor ökar på grund av att dessa spår kräver mindre underhåll och har enligt vissa undersökningar en lägre livscykelkostnad i jämförelse med ballasterat spår. Ballastfritt spår består oftast av en betongplatta till vilken rälsen är kopplad genom befästningar. Plattan är i sin tur kopplad till underbyggnaden genom skjuvförbindare som håller plattan på plats. När ballastfritt spår används i bebodda områden är det ibland nödvändigt att ta till vibrations- och ljuddämpande åtgärder. En åtgärd som används på brokonstruktioner för att minska vibrationer och ljudföroreningar är att montera en vibrationsdämpande matta, som är tillverkad av ett elastiskt material, mellan betongplattan och broöverbyggnaden. I detta examensarbetet undersöks hur den vibrationsdämpande mattans egenskaper påverkar rälsspänningarna. Resultaten från undersökningen visar att spänningarna i rälsen minskar med cirka 3–7 % (beroende på det elastiska stödets styvhet, lastpositioner och mattans egenskaper) när en elastisk matta installeras under spårplattan i jämförelse med när ingen matta används. När mattans tjocklek ökar och när styvheten sänks minskar spänningarna med cirka 1 % i jämförelse mellan den tjockaste och tunnaste mattan. Denna minskning av spänningarna antas bero på att den vibrationsdämpande mattan som är monterad på sidan av skjuvförbindarna ger en möjlighet för spåret och bron att förskjutas fritt parallellt varandra innan en interaktion mellan spår och bro uppstår. Det visade sig även att om friktionen mellan mattan och broöverbyggnaden medräknas ökar spänningarna i rälsen. Detta beror på att mattan då skapar en större interaktion mellan spåret och bron gentemot fallet då mattans horisontella styvhet inte beaktas.
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Benjamin, Simon. "Cristal composite SLAB pompé latéralement par diodes laser /." [S.l.] : [s.n.], 2003. http://library.epfl.ch/theses/?nr=2871.
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Fulford, Benjamin S. "An industrial ultrashort pulse thin slab laser amplifier." Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/3238.
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Iskandarani, Saad S. "Electromagnetic wave propagation in anisotropic uniaxial slab waveguide." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1182437230.
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Mensmann, Jörg, Timo Ropinski, and Klaus Hinrichs. "Slab-Based Raycasting : Efficient Volume Rendering with CUDA." University of Münster, Germany, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93207.
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GPU-based raycasting is the state-of-the-art rendering technique for interactive volume visualization. The ray traversal is usually implemented in a fragment shader, utilizing the hardware in a way that was not originally intended. New programming interfaces for stream processing, such as CUDA, support a more general programming model and the use of additional device features, which are not accessible through traditional shader programming.We propose a slab-based raycasting technique that is modeled specifically to use these features to accelerate volume rendering. This technique is based on experience gained from comparing fragment shader implementations of basic raycasting to implementations directly translated to CUDA kernels. The comparison covers direct volume rendering with a variety of optional features, e.g., gradient and lighting calculations.
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Cho, Soon Ho. "Slab behaviour in composite beams at web openings." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74647.
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An explanation is provided for the slab behaviour in composite beams at web holes where the concrete slab carries heavy vertical shear. This is based on the truss concept, and requires consideration of shear studs in the hole region as vertical tension members. According to this, a structural action between the concrete slab and shear connectors for carrying or transferring vertical shear to the steel beam was clearly identified.On the basis of the slab behaviour identified, truss idealizations capable of determining the slab shear carrying capacity in a rational manner were developed. Then, the ultimate strength for composite beams at web holes was formulated including the truss idealizations. Another ultimate strength analysis accounting for the slab shear carrying capacity in a simple manner, which was also developed during this research project, is given. This provided the fundamental solution procedure for the plastic analysis used.
A series of nine tests was carried out with particular attention being directed to the verification of the proposed truss analogy. The major test parameters included the configurations of the studs in the hole region, the width of the concrete slab and stud detailing near the high moment end of the hole. The ultimate strength predictions were made by the two methods developed, and compared with previous and present test results.
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Millas, David Pelaez. "Thin slab and planar waveguide solid state lasers." Thesis, Heriot-Watt University, 1999. http://hdl.handle.net/10399/1174.
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Agarwal, Anjali. "Bayesian variable selection with spike-and-slab priors." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461940937.
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Subedi, Shobha K. "Load Rating of Flat Slab Bridges Without Plans." Youngstown State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1471608754.
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Russell, Justin. "Progressive collapse of reinforced concrete flat slab structures." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28991/.
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In 1968 a relatively small gas exposition on the 18th floor of the Ronan Point tower building resulted in the partial collapse of the structure. This event highlighted that progress collapse may occur to structures under an accidental loading event. Other events, including the bombing of the Murrah federal building in 1993 in Oklahoma, have resulted in the common design requirement that a structure be capable of surviving the removal of a load bearing element. This approach, often referred to as the sudden column loss scenario, effectively ignores the cause of the damage and focuses on the structure’s response afterwards. The refinement of the analysis varies, with options to include the nonlinear and dynamic behaviours associated with extreme events, or to use simplified linear and static models with factors included to account for the full behaviour. Previous research into progressive collapse has highlighted that providing ductility in the connections, and avoiding brittle failures, is important in ensuring the structure maintains integrity after a column loss event. However, the majority of this work has been focused on the behaviour of steel and Reinforced Concrete (RC) frame structures. As flat slab construction is a popular method for many structures, due to the flexibility it offers for layouts and its low storey heights, it is an important to consider flat slab behaviour in more detail. Furthermore, slab elements behave differently to frame structures due to the Alternative Load Paths (ALPs) that can develop after a column loss via two-dimensional bending mechanisms. Additionally, punching shear failure is a known issue due to the thin section depths. This work addresses the issue of the response of RC flat slab structures after a sudden column loss. As previous case studies have demonstrated that brittle failures may lead to progressive collapse of such structures, a complete understanding of the response is required. The nonlinear behaviour of a slab structure, due to both material and geometric factors, is investigated to determine the additional capacity available beyond the usual design limits. Additionally, the dynamic factors involved, primarily due to inertial effects, are also considered. To achieve this, experimental and numerical studies were conducted. A series of 1/3 scale models of slab substructures were constructed to replicate column loss events. Two types of tests were conducted, a static push down test with a support removed and a sudden dynamic column removal case. Displacements, strains and support reactions were recorded throughout, along with cracking patterns. For the dynamic tests a high speed camera was used to obtain the deflection response in the short time period after removal and to observe the formation of cracks. Comparisons between the two cases allowed determination of the dynamic effects on the response of the system. The experimental programme was then replicated using a Finite Element (FE) model. The results taken from the experimental case were used to validate the material and modelling assumptions made during the numerical simulations. This validated model was finally used to investigate a wider range of variables and assess the response of typical structural arrangements, with particular focus on the nonlinear and dynamic factors involved after a sudden column loss. The experimental and numeral investigations demonstrated that after the loss of a column, flat slab structures can maintain integrity due to a change in the load paths away from the removal location. Although in some cases a large amount of flexural damage to the concrete and reinforcement occurred, such effects did not lead to complete failure. However, during the experimental programme some punching shear failures occurred, usually at the corner column locations. From the numerical analysis, shear forces of over twice the fully supported condition occurred as a result of removing a column, which may exceed the designed capacity. Comparisons between a static and dynamic analysis provides information into a suitable Dynamic Amplification Factor (DAF) for use with simplified modelling approaches. Based on the range of structures considered, the maximum increase in deflections as a result of a sudden removal was 1.62 times the static case, this is less than the commonly used factor of 2.0. Additionally, this factor reduces as the nonlinearity increases due to further damage, with a smallest DAF calculated at 1.39. This factor can be reduced further if the column is not removed instantaneously. Finally, the material strengthening effect, due to high strain rates, was considered with the conclusion that as such effects only make a limited increase in the capacity of the slab and may be conservatively ignored. In conclusion, RC flat slab structures are capable of resisting progressive collapse after the loss of a column. This is primarily due to their ability to develop ALPs. However, while flexural damage is usually fairly minimal, progressive punching shear failure is a critical design condition as it may result in a complete collapse. Furthermore, the inertial effects involved after a sudden removal can increase the damage sustained, although current design methods may be over conservative.
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Faris, Adam S. "An integral precast approach slab to bridge connection." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1473202.
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Cano, Juan Pablo Vasco. "Reflectivity calculations in L3 photonic crystal slab cavities." Universidade Federal de Minas Gerais, 2013. http://hdl.handle.net/1843/BUOS-97WHM5.
Full textAbstract:
In this work, a detailed study is made of the reflectivity spectrum
of L3 photonic crystal slab cavities. The scattering matrix method for
patterned multilayer photonic structures is implemented to study the
coupling between the scattering and bounded states in the crystal.
Some modifications are made in the original treatment of the method
in order to describe arbitrary geometrical shapes of the incident light
spot and to calculate the reflectivity in a cross-polarized scheme. The
lineshape of the fundamental mode resonance is well fitted by the
Fano formula, evidencing an electromagnetic Fano interference phe-nomenon in the reflection process. It is found that the lineshape of
the Fano resonance can be accurately controlled and reversed by the
polarization of the incident field, and the continuum contribution in
the Fano phenomenon can be enhanced increasing the incident spot
size. Good agreement is obtained between the theoretical and experimental results. The outline of the work is as follows: Chapter one presents a gen-eral state of the art in the photonic crystal area. Then, in chapter two, the fundamental concepts of the solid state physics and electromagnetism in inhomogeneous and periodic media are described. In chapter three a revision is made of the standard plane wave expansion
method applied to two dimensional photonic crystals. In chapter four
the scattering matrix treatment of patterned multilayer structures is
formulated in a general form, to study the diffractive properties of
photonic structures. Chapter five presents the implementation of the
scattering matrix method to photonic crystal slabs and in chapter six
the principal results of this work are presented and discussed. Finally,
chapter seven contains the principal conclusions and perspectives.Neste trabalho é feito um estudo detalhado do espectro de refletividade de cavidades L3 em cristais fotônicos. O método de matriz de espalhamento aplicado a estruturas fotônicas multicamadas é implementado para estudar o acoplamento entre os estados dispersados e confinados pelo cristal. Algumas modificações são feitas no tratamento inicial do método, a fim de descrever geometrias arbitrárias do feixe de luz incidente e calcular a refletividade em um esquema de polarização cruzada. A forma de linha da ressonância do modo fundamental é bem ajustada pela fórmula de Fano, evidenciando um fenômeno de interferência de Fano eletromagnético no processo de reflexão. Verifica-se que a ressonância de Fano pode ser sintonizada com precisão via a polarização do campo incidente. Demonstra-se ainda que a importância relativa das contribuições da componente contínua e da componente discreta na interferência de Fano pode também ser controlada através da variação do tamanho do feixe incidente. Um bom acordo é obtido entre os resultados teóricos e experimentais. O esboço do trabalho é o seguinte: O Capítulo 1 apresenta o estado geral da arte na área de cristais fotônicos. Em seguida, no Capítulo 2, são descritos os conceitos fundamentais da física do estado sólido e eletromagnetismo em meios heterogêneos e periódicos. No Capítulo 3 é feita uma revisão do método padrão de expansão em ondas planas aplicado a cristais fotônicos de duas dimensões. No Capítulo 4, o tratamento de matriz de espalhamento para estruturas fotônicas multicamadas é formulado de uma forma geral para estudar as propriedades de difração de estruturas fotônicas. O Capítulo 5 apresenta a implementação do método de matriz de espalhamento a lâminas de cristal fotônico e no Capítulo 6, os principais resultados deste trabalho são apresentados e discutidos. Finalmente, o Capítulo 7 contém as principais conclusões e perspectivas.
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Shumway, LeGrand Jared. "High-Voltage Measurements Using Slab-Coupled Optical Sensors." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6499.
Full textAbstract:
This work highlights slab coupled optical sensors (SCOS) and their ability to measure high voltages. Although other high voltage measurement techniques exist, most of these techniques are electrical devices and are therefore more susceptible to stray ground currents and other electromagnetic interferences (EMI), which may cause signal distortion. Optical sensors are less susceptible to such interferences and these sensors, such as the Pockels cell, have been used in measuring high voltage. SCOS offer an alternative method of measuring high voltage optically. Consisting of an optical fiber and an electro-optic slab waveguide, SCOS have the advantage of being very small in size (0.2 mm x 0.3 mm cross-section), simpler composition, and potentially less coupling losses. Issues associated with high voltage measurements are addressed such as unwanted corona, arcing, and EMI. Solutions are also explored which include insolating materials, electrode geometries, Faraday cages, and using optical sensors such as SCOS. Although the SCOS has been traditionally used to measure electric field, the SCOS is able to measure high voltage through the use of an electrode structure. The SCOS' ability to measure high voltage is showcase through the construction and output measurements of several high voltage systems: an ignition coil-based circuit, a dual ignition coil circuit, a Marx generator, and a 200 kV generator used in a capacitor discharge configuration. These measurements show the SCOS' ability to measure at least 111 kV capacitor discharges with 6.6 ns rise times and other various high voltage waveforms.
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Chadderdon, Spencer L. "Application Improvements of Slab-Coupled Optical Fiber Sensors." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3976.
Full textAbstract:
This dissertation explores techniques for improving slab-coupled optical fiber sensor (SCOS) technology for use in specific applications and sensing configurations. SCOS are advantageous for their small size and all-dielectric composition which permit non-intrusive measurement of electric fields within compact environments; however, their small size also limits their sensitivity. This work performs a thorough analysis of the factors contributing to the performance of SCOS and demonstrates methods which improve SCOS, while maintaining its small dimensions and high level of directional sensitivity. These improvements include increasing the sensitivity by 9x, improving the frequency response to include sub 300 kHz frequencies, and developing a method to tune the resonances. The analysis shows that the best material for the slab waveguide is an electro-optic polymer because of its low RF permittivity combined with high electro-optic coefficient. Additional improvements are based on changing the crystal orientation to a transverse configuration, which enhances the sensitivity due to a combined increase in the effective electro-optic coefficient and electric field penetration into the slab. The transverse SCOS configuration not only improves the overall sensitivity but increases the directional sensitivity of the SCOS. Lithium niobate and electro-optic polymer are both experimentally shown to exhibit minimal frequency dependent sensitivity making them suitable for broad frequency applications. Simultaneous interrogation of multiple SCOS with a single tunable laser is achieved by tuning the resonant wavelengths of KTP SCOS so their resonances overlap.
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Lynner, Colton, Megan L. Anderson, Daniel E. Portner, Susan L. Beck, and Hersh Gilbert. "Mantle flow through a tear in the Nazca slab inferred from shear wave splitting." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/625357.
Full textAbstract:
A tear in the subducting Nazca slab is located between the end of the Pampean flat slab and normally subducting oceanic lithosphere. Tomographic studies suggest mantle material flows through this opening. The best way to probe this hypothesis is through observations of seismic anisotropy, such as shear wave splitting. We examine patterns of shear wave splitting using data from two seismic deployments in Argentina that lay updip of the slab tear. We observe a simple pattern of plate-motion-parallel fast splitting directions, indicative of plate-motion-parallel mantle flow, beneath the majority of the stations. Our observed splitting contrasts previous observations to the north and south of the flat slab region. Since plate-motion-parallel splitting occurs only coincidentally with the slab tear, we propose mantle material flows through the opening resulting in Nazca plate-motion-parallel flow in both the subslab mantle and mantle wedge.
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Eriksson, Alexander, and Veronica Flykt. "Concrete floor : Design of prefabricated pre-stressed hollow core slabs with verification through PRE-Stress and comparison with site-cast slab." Thesis, KTH, Byggteknik och design, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279158.
Full textAbstract:
The most common prefabricated concrete slabs are hollow core slabs, which are usually pre-tensioned. How to design these parts is not compiled today in a manual where it is clear how this is done, this knowledge is generally classified as expert knowledge. The purpose was to bring forth how to design prefabricated pre-stressed hollow core slabs, HD/F, and then create a design aid that is compared by hand calculations with the PRE-Stress design program from StruSoft. Furthermore, to compare it with site-cast concrete slabs to see differences in the amount of material and the thickness of the structure under the same conditions.The design aid is not complete as some limitations had to be made. When it comes to results, the hand calculations in comparison with PRE-Stress have not resulted in identical answers but have proven to be on the safe side consistently through the design, which indicates that the design aid is fully functional. In the comparison with site-cast concrete slabs, it can be noted that prestressed hollow core slabs require less concrete volume, slimmer construction, and longer span widths but greater reinforcement volume.Det vanligaste prefabricerade betongbjälklaget är håldäcksplattor som oftast är spännarmerade. Hur man dimensionerar dessa bärverksdelar finns idag inte samlat i en handbok där det står tydligt hur man gör, den kunskapen klassas generellt som expertiskunskap. Syftet var att ta fram hur man dimensionerar prefabricerade förspända håldäcksplattor, HD/F, och sedan skapa ett dimensioneringshjälpmedel som jämförs genom handberäkningar med PRE-Stress dimensioneringsprogram från StruSoft. Vidare genomfördes jämförande beräkningar för platsgjutet betongbjälklag för att se skillnader i materialmängd och konstruktionstjocklek under samma förutsättningar.Dimensioneringshjälpmedlet är inte komplett då vissa avgränsningar behövts göras. När det kommer till resultat har handberäkningar i jämförelse med PRE-Stress inte resulterat i identiska svar, men visat sig hamna på säkra sidan konsekvent genom dimensioneringen vilket tyder på att dimensioneringshjälpmedlet är fullt användbart. I jämförelsen med platsgjutet bjälklag kan man konstatera att förspända håldäcksplattor ger mindre betongvolym, slankare konstruktion och längre spännvidder men större armeringsmängd.
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Loneberg, Agnes, and Linnea Kvarnvik. "Val av bjälklag : En jämförelse av massivt betongbjälklag, plattbärlag och samverkansbjälklag av trä och betong ur ekonomi och miljösynpunkt." Thesis, Tekniska Högskolan, Jönköping University, JTH, Byggnadsteknik och belysningsvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-50241.
Full textAbstract:
Purpose: In 2016, the construction industry produced 21% of Sweden's total carbon dioxide emissions. To reduce these emissions, an alternative is to choose building components from an environmental perspective. At the same time, the client of the building wants to keep the costs of production down. An multi criteria analysis is a tool for weighing different aspects against each other. In this report environmental aspects and the economic aspects of three different slabs will be compared and analyzed to facilitate the choice of slabs. The slabs that have been analyzed are solid concrete slabs, filigree floor slabs and composite slabs of wood and concrete. Method: The report is based on a reference project of an office building with a span of 6 m and an area of 1000 m2 located in Jönköping. This information is used for calculating requirements and transport. To obtain the desired results, an Life Cycle Assessment and a cost analysis have been performed along with a document analysis as well as contact with suppliers of the slabs. The results from the Life Cycle Assessment and the cost analysis were then used to perform an multi criteria analysis where the various aspects were weighed together. Interviews were conducted to strengthen the weighing in multi criteria analysis and to find out how the choice of beams currently applies to the company PEAB. Findings: The results from the document analysis show that filigree floor slabs are the most advantageous when it comes to finances and that wood and concrete slabs are most advantageous from an environmental point of view. In the analysis of the empirical data collected from the interviews, it is shown that the financial aspect is more important and should be weighted higher than the environmental aspect in the multicriteria analysis. Multi criteria analysis shows that filigree floor is the most advantageous in both economy and environment. During the planning and in the choice of flooring, finances are one of the most important aspects, but also the working environment and the ease of installation. Implications: The conclusion of this report is that the filigree floor slabs are the most advantageous choice of floor slabs in terms of both economic and environmental aspects. This flooring is also shown to be the flooring that is often chosen for buildings similar to the work's reference project. This result is considered to be general for similar constructions as the reference project. Limitations: The work only considers the Life Cycle Assessment category Climate impact and greenhouse gases and considers only the period of cradle to gate (A1-A4). The costs that are calculated are for the purchase of flooring and materials, installation and transportSyfte: Byggbranschen producerade år 2016 21% av Sveriges totala koldioxidutsläpp. För att minska dessa utsläpp är ett alternativ att välja byggdelar utifrån miljöperspektiv. Samtidigt vill byggherren hålla ner kostnaderna för produktionen. En multikriterieanalys är ett verktyg för att väga olika aspekter mot varandra. I detta arbete kommer miljöaspekter och de ekonomiska aspekterna för tre olika bjälklag att jämföras och analyseras för att underlätta vid val av bjälklag. Bjälklagen som analyserats är massivt betongbjälklag, plattbärlag samt samverkansbjälklag utav trä och betong. Metod: Arbetet utgår ifrån ett referensprojekt om en kontorsbyggnad med en spännvidd på 6 m och en yta på 1000 m2 beläget i Jönköping. Dessa uppgifter används för beräkning av krav samt transport. För att få fram de resultat som önskas har en livscykelanalys och en kostnadsanalys utförts utefter en dokumentanalys samt kontakt med leverantörer av bjälklagen. Resultatet ifrån livscykelanalysen och kostnadsanalysen användes sedan för att utföra en multikriterieanalys där de olika aspekterna vägdes samman. Intervjuer utfördes för att stärka vägningen i multikriterieanalysen samt för att få reda på hur valet av bjälklag går till för nuvarande på företaget PEAB. Resultat: Resultatet från dokumentanalysen visar att plattbärlag är det mest fördelaktiga när det gäller ekonomi och att samverkansbjälklag av trä och betong är mest fördelaktigt ur miljösynpunkt. I analysen av den insamlade empirin från intervjuerna visas det att ekonomiaspekten är viktigare och borde viktas högre än miljöaspekten i multikriterieanalysen. Multikriterieanalysen visar på att plattbärlag är det bjälklag som är mest fördelaktigt inom både ekonomi och miljö. Under projekteringen och i valet av bjälklag är ekonomi en av de viktigaste aspekterna men även arbetsmiljön och lättheten att montera. Konsekvenser: Slutsatsen av detta arbete är att plattbärlaget är det mest fördelaktiga valet av bjälklag med tanke på både ekonomi- och miljöaspekter. Detta bjälklag visas också vara det bjälklag som ofta väljs för byggnader liknande arbetets referensprojekt. Detta resultat anses vara generellt för liknande konstruktion som referensprojektet. Begränsningar: Arbetet tar enbart hänsyn till livscykelanalyskategorin Klimatpåverkan och växthusgaser och avser enbart vagga till grind (A1-A4). De kostnader som beräknas är för inköp av bjälklag och material, montering samt transport.
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Deaton, James B. "A Finite Element Approach to Reinforced Concrete Slab Design." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7188.
Full textAbstract:
The objective of this study was the development of a procedure in GT STRUDL to design reinforced concrete flat plate systems based on the results of finite element analysis.
The current state-of-practice of reinforced concrete flat plate design was reviewed, including the ACI direct design and equivalent frame techniques, the yield line method, and the strip design method. The principles of these methods along with a critical evaluation of their applicability and limitations were presented as motivation for a finite element based design procedure. Additionally, the current state-of-the-art of flat plate design based on finite element results was presented, along with various flat plate modeling techniques. Design methodologies studied included the Wood and Armer approach, based on element stress resultants, and the resultant force approach, based on element forces.
A flat plate design procedure based on the element force approach was embodied in the DESIGN SLAB command, which was implemented in GT STRUDL. The DESIGN SLAB command provides the user the ability to design a slab section by specifying a cut definition and several optional design parameters. The procedure determines all nodes and elements along the cut, computes the resultant moment design envelope acting on the cross-section, and designs the slab for flexure in accordance with provisions of ACI 318-02.
Design examples presented include single-panel flat plate systems with various support conditions as well as multi-panel systems with regular and irregular column spacing. These examples allowed for critical comparison with results from experimental studies and currently applied design methods in order to determine the applicability of the implemented procedure. The DESIGN SLAB command was shown to produce design moments in agreement with experimental data as well as conventional design techniques for regular configurations. The examples additionally showed that when cuts were not oriented orthogonally to the directions of principle bending, resulting designs based on element forces could significantly under-reinforce the cross-section due to significant torsional effects.
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Li, Zongyu. "Computer simulation of the push-type slab reheating furnace." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26308.
Full textAbstract:
A mathematical heat-transfer model for the slab reheating furnace has been
developed. Radiation in the furnace chamber was calculated using the zone method, with
the gas temperature distribution being assumed, and heat transfer in the slab was
determined using a finite-difference approximation of two-dimensional transient conduction.
These individual calculations were coupled to allow prediction of the temperature profiles in,
and heat flux to, refractory walls and slabs at any point inside the furnace.
The emissive/absorptive characteristics of the gas mixture within the furnace chamber were simulated with a clear-plus-two-gray-gas model which simulated the real gas behaviour to within 5%. For the calculation of radiative exchanges, the furnace chamber was subdivided into 432 isothermal zones, and radiative exchange factors to slab surfaces were evaluated rather than relying on empirical or experimental estimations as in previous studies. An iterative technique was devised in order to combine the radiative and slab heat conduction calculations. For the purpose of identifying the mechanism of skidmark formation, the region of skidrail/slab contact was examined in detail by introducing a radiation shielding factor to account for the presence of the skid structure.
The gas temperature distribution inside the furnace chamber was found to have a
significant influence on the heat flux to the slab surface. Nonuniform gas temperature
transverse to the push direction causes an uneven transverse slab temperature distribution
and subsequent rolling problems. Higher gas temperatures near the sidewall refractory were shown to cause serious distortion of the transverse heat-flux distribution.
The heating practice for the hot charging of slabs was simulated by the model in order to improve the process from the standpoint of energy conservation and slab temperature uniformity. Model predictions have shown that the fuel input could be reduced substantially near the slab entrance where the port to the chimney is located, thus maximizing the residence time of the combustion products. Alternatively the throughput of the furnace can be increased if the fuel input remains the same as for charging cold slabs. The extent of increase in production rate can be determined by the off-line computer model.
The model was used to predict the thermal behaviour of slabs for various thicknesses, steel grades and push rates. The results consistently indicated that the selection of an appropriate push rate is crucial to the final temperature distribution.
The study of the mechanism of skidmark formation showed' that the radiation shielding effect of the skidrail was the dominant factor, accounting for 90% of the heating deficit around the slab/skidrail contact region. Computer simulation of the possible measures that could be taken to alleviate the skidmark formation has indicated that reducing the height and width of the skidrail improved radiative heat transfer in the contact region. Coating highly reflective materials on the exterior surface of the skidrail to increase reflectivity from 0.3 to 0.8, could enhance heat transfer locally around the the skidrail by about 25% - 30% when the skidrail temperature is lower than the slab bottom temperature.Applied Science, Faculty of
Materials Engineering, Department of
Graduate