Dissertations / Theses on the topic 'Road bridges'

There are over 40,000 road bridges in the UK and most of them are over a hundred years old. These bridges were not designed to carry today's modern traffic and the everincreasing live loads especially with the introduction of 40 tonne lorries since January 1999. Moreover, in the case of multi-ring brickwork arches the penetration of rainwater and/or overloading with the passage of time breaks the adhesion between the rings leading to ring separation. The loss of continuum behaviour is accompanied by a significant drop in load carrying capacity. It is important that they continue to perform their functions. Sympathetic strengthening is preferred to demolition and replacement. A large amount of work has, in recent years, been devoted to the study of the behaviour of brickwork arch bridges subjected to monotonic loading. However, little is known about the behaviour under cyclic loading. The thesis reports the results of tests under cyclic loading applied at the quarter spans on six large-scale brickwork arch bridges of spans 3m and 5m. Some of them were constructed with damp sand between the brickwork rings, which simulate the defect of ring separation in real bridges. The tests were used to develop a better understanding about the behaviour and failure mechanisms of these arches subjected to cyclic loading. Additionally, the efficacy of surface strengthening to the structural performance of multi-ring brickwork arches was investigated. Both the ring separation and surface strengthening affects the behaviour of arches subjected to cyclic loading where the former reduces the carrying capacity and the latter increases the carrying capacity. The static failure loads of brickwork arches were predicted using four different methods: the mechanism method, Gilbert's 'RING' program, the elastic method and the FE method using ABAQUS software. It was found that the mechanism method and the 'RING' program were conservative in predicting the carrying capacity of the tested arches.

Infrastructure investment and management often incur high capital cost that dictates the decision making during the planning phase. Future operation and maintenance costs have been considered but in different methods. With the pressure of existing aging infrastructure, the need to cut down maintenance cost has been highlighted. Currently, there is a lack of a standardized framework for decision making. Delay in decision making will lead to construction delay and increase in construction cost. This MSc thesis discusses the various frameworks available and proposes the optimal framework. Life Cycle Cost Analysis (LCCA) provides a methodology to evaluate an object, e.g. a road, through including investment, operation, maintenance, dismantling and landfill or recycling. Higher cost saving will be possible to achieve if LCCA can be applied during the planning phase of the construction. Thus, LCCA is studied and applied on a case study of a section along a 9- km road in south of Sweden. By considering the specific site conditions such as soil profile and road alignment, this thesis evaluates its effect on LCCA. Sensitivity analysis is carried out on the cost output due to uncertainty variable input of the data. The aim of this thesis is to formulate a generic model/tool for decision making based on LCCA methodology on the project level. The rules and regulations provided by Trafikverket (Swedish Transport Administration) and ISO standard for life cycle costing are used as parameters during the analysis. The model described above can be used in different countries if these parameters are redefined by adapting local standards and conditions. This thesis demonstrates the application of the model with a case study to discuss the difference between two different alternatives. The case study compares two alternatives for the same stretch of the road. The first alternative proposes a longer bridge while the second alternative provides a shorter bridge. The result shows that the first alternative has slightly lower LCC compared to the second alternative. Through understanding all the costs connected to the project, cost calculation has been adjusted to ensure accuracy of the data input. Finally, the result from the cost comparison is tested with Monte Carlo Simulation to manage uncertainty risks.

Scientific research has identified road roughness as a significant factor that contributes to increased vehicle dynamic wheel loads and therefore damage to pavements and bridges. The other factors include vehicle speed and vehicle suspension type. More specifically and regarding road roughness, research has shown that damaging effects are caused by certain wavelengths and features in road profiles and not the overall road roughness. Various methods of classifying road roughness based on the ride quality are available. These methods, though important, are limited in identifying the location of features along road profiles that cause exceptionally high dynamic wheel loads hence damage. It is the development of a methodology for identifying the location of these abnormally high dynamic wheel forces that this thesis addresses. A vehicle-road interaction model was developed for this research. This computer model uses a quarter vehicle model and recorded road profile elevation data to simulate the response of half a vehicle axle (quarter vehicle) driving along a road. 47 road profiles over 17 bridges were measured to run the model. Signal processing techniques developed by electrical and mechanical engineers have been used as an additional tool to road profile analysis. These techniques are very powerful and their application to road profile investigations is significant. Using computer simulation and by combining ride and damage criteria analysis, a methodology of identifying segments of road that induce high dynamic wheel forces and the location of abnormally high dynamic wheel forces has been established.

Roads are primary agents of habitat fragmentation and transform landscapes on a global scale. Roads remove habitat and create barriers or filters to the movement of many wildlife species. Moreover, roads disrupt population processes by breaking up continuous populations into smaller, isolated subpopulations or metapopulations, which can suffer genetic drift and become more vulnerable to stochastic processes. Consequently, understanding and mitigating the impact of roads on wildlife has attracted increasing international interest in recent decades. Foremost in efforts to re-connect wildlife populations severed by roads has been the installation of crossing-structures. These are engineered structures designed to provide the opportunity for animals to safely cross either over the road (e.g. land-bridges, rope or wooden canopy-bridges) or under the road (e.g. underpasses, culverts, ecopipes). Crossing-structures enhance the permeability of roads to animal movement thereby improving the ‘functional connectivity’ of the surrounding landscape, or the degree to which the inter-fragment landscape (matrix) facilitates movement. Crossing-structures have thus become a common feature of new road projects in developed countries. Research into the efficacy of crossing-structures is very much in its infancy and has largely focused on assessing whether structures are being used by different wildlife species. As a consequence, we know very little about higher order questions pertaining to population processes, particularly whether the viability of local populations is enhanced by the deployment of crossing-structures. Furthermore, the deployment of crossing-structures has largely focused on terrestrial vertebrates and scant attention has been directed at mitigating road impacts on arboreal mammals, particularly gliding mammals (gliders). This thesis endeavours to address some of these information gaps by presenting the results of a number of investigations into wildlife use of road crossing-structures located in subtropical, eastern Australia. The topics of investigation include: i) glider use of wooden poles on a road land-bridge; ii) home-ranges of gliders residing near road crossing-structures; iii) modelling the effect of connecting habitat patches across road-gaps on glider metapopulation viability; and, vi) determining the effect of road widening on bandicoot use of highway underpasses. They represent the first studies of their kind to investigate such topics. The Australian squirrel glider Petaurus norfolcensis (Marsupialia: Diprotodontia) is a gliding marsupial distributed along the eastern seaboard of Australia. It is listed as threatened in the southern part of its geographic range due to habitat fragmentation. I investigated whether 7-m high wooden poles installed on a land-bridge could enable squirrel gliders to cross a road canopy-gap at two locations in Brisbane, the capital city of Queensland. This represented the first attempt in the world to facilitate road crossing by a gliding mammal in this way. At one location no road crossing was revealed from trapping over a 3-year period. Radio-tracking over 8 months revealed 3 occasions when animals whose home-ranges were aligned along the road had crossed the road. Hair-sampling devices revealed use of the poles at one location during 15 of 20 sampling sessions over a 3-year period, and at the second location during 6 of 6 sampling sessions over a 6-month period. Detection of hair on all poles during some sessions at both locations suggests complete crossings could occur. These observations suggest that wooden poles can be used to facilitate road-crossing by gliding mammals. Obtaining information on the use of novel road-crossing technologies such as gliding poles is a necessary first step to understanding their efficacy. However, the ultimate test of a crossing-structure’s effectiveness is in establishing to what extent has it alleviated the barrier effect of the road and prevented the extirpation of local populations. Accordingly, I utilised the population modelling program VORTEX to assess the viability of a metapopulation of squirrel gliders and Australia’s largest gliding marsupial, the greater glider (Petauroides volans), occurring in forest remnants in the fastest urbanising region of Australia. Population studies were conducted over two years within two of these forest remnants (one small, one large) connected across a major road by a land-bridge with gliding poles and rope canopy-bridges. Whereas I obtained direct evidence of squirrel glider use of the land-bridge poles, it is currently unknown whether greater gliders will use the crossing structures but available tree height and spacing do not allow a glide crossing and fences with metal flashing prevent access to the road by terrestrial and arboreal mammals. My modelling revealed that even a relatively low rate of dispersal facilitated by these structures would substantially reduce the probability of extirpation of the smaller subpopulation for both glider species. This rate of dispersal is plausible given the small distance involved (~50 m). The inclusion of wildfire as a catastrophe in my model suggests that these two remnants may encounter an undesirable level of extinction risk. This can be reduced to an acceptable level by including inter-patch movement via dispersal among other forest remnants. However, this requires connection to a very large remnant 8 km away, through a set of smaller remnants that straddle two motorways. These motorways create discontinuities in forest cover that are beyond the gliding ability of both these species and will require the deployment of crossing-structures to allow inter-patch movement. Whereas our knowledge of wildlife use of road crossing-structures has grown considerably in recent years, little is known about the effect that road widening may have on patterns of use by target fauna. To address this, I investigated the effect that duplicating a highway had on bandicoot (Marsupialia: Peramelemorphia) use of underpasses at Brunswick Heads in north east New South Wales (NSW). This study represented one of the first of its kind in Australia and spanned the period of pre and post-construction over an eight year period. Evidence from trapping data showed that individuals of the two bandicoot species present at the study site (i.e. Isoodon macrourus and Perameles nasuta) incorporated both sides of the road corridor into their home ranges and that the majority of movements were likely associated with foraging. The trapping data also demonstrated spatial overlap between and within sexes and congeners suggesting that underpasses were functionally available to resident animals and were each being used by multiple individuals. Despite this, gaining clear insights on the effect that road-widening had on underpass use by bandicoots was confounded by drought, loss of high quality habitat, a decline in bandicoot abundance, the presence of foxes and different design characteristics of new underpasses. Further surveys are required at Brunswick Heads to elucidate this issue. The results of my investigations on bandicoot and glider use of road crossing-structures provide strong support for the need to manage road impacts on wildlife at multiple scales. At the patch or site-level, a number of enhancements are required to improve the functionality of the investigated crossing-structures and to make the study sites more amenable to the target species. At the landscape-level, management needs to focus on improving functional connectivity in the surrounding landscape to strengthen the viability of local metapopulations. This will require the combination of habitat restoration works, wildfire control and the deployment of crossing structures where large roads and motorways breach forest cover. In the case of gliders, the deployment of crossing-structures can be achieved rapidly and cost-effectively by installing gliding poles along motorway edges and in median strips at locations where forest cover is breached. Future research at these study sites needs to continue for much longer periods (i.e. 5-10 years) and incorporate genetic techniques. This will assist in improving our understanding of the isolation effects of road barriers and whether or not gene flow is restored by the installation of crossing-structures. This should be routinely combined with viability assessments (e.g. PVA) to determine how populations are affected by roads and whether they might benefit from crossing structures. Research is also required to provide insights to dispersal behaviour, particularly for gliders, and the likely use of road-crossing structures. Loss of habitat and habitat connections is continuing in my study landscapes and this is likely to have dire consequences for wildlife if land managers are unable to retain appropriate habitat cover with corridors and install effective wildlife road crossing-structures where large roads bisect wildlife habitat.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Environment<br>Science, Environment, Engineering and Technology<br>Full Text

Almost all the sources on modernism originate material transformations in Western world to industrial revolution while mental ones to enlightenment. In all these narrations, technology, engineering, and modernism are considered as correlated. Besides these concepts, the everyday life rituals that were naturally constructed in the historical process also strengthen this attitude. Then, what are the meanings of the same concepts in a country that experience a reverse process instead of the modernization through industrialization? How new technologies had adapted to local circumstances of an unindustrialized country? While having these questions in mind, this study intends to identify the role of engineer and to reflect on the importance of technology on Turkish modernization project, hence, this dissertation is an historical inquiry into the role played by new building technologies and civil engineering. It covers a broad period extending from late Ottoman to 1960. Among many prestigious building types of engineering such as silos, dams, harbors, factories, railroad etc. that also became popular representations of development, prosperity and modernity, the bridges have been focused on with a particular emphasis because of both their importance for engineering and construction of transportation networks.

The primary aim of the research work is to focus on the effects of climate change for maintaining physical infrastructures (i.e. such as buildings, dams, bridges, road pavements and other road infrastructures). As infrastructure requires major investment, it is important to build necessary management system to cope with future changes. This means that recognition of likely climate change impacts and appropriate adaptation measures are critical. However, most infrastructures has been designed, built and maintained on the premise that the future climate will be similar to that experienced in the past. Since the occurrence of the most recent climate disasters in Queensland, Australia, it has become mandatory to put especial policies for design and maintenance purposes of infrastructures . Recognition of the risks associated with climate change is a valuable initial step towards improved planning of new infrastructure investments and mitigating. Road infrastructure especially pavement requires special type of maintenance policy as the material of pavement like bitumen is very much sensitive to these types of effects such as moisture or temperature.<br>Thesis (Masters)<br>Master of Philosophy (MPhil)<br>Griffith School of Engineering<br>Science, Environment, Engineering and Technology<br>Full Text

[EN] Bridges, as an important component of infrastructure, are expected to meet all the requirements for a modern society. Traditionally, the primary aim in bridge design has been to achieve the lowest cost while guaranteeing the structural efficiency. However, concerns regarding building a more sustainable future have change the priorities of society. Ecological and durable structures are increasingly demanded. Under these premises, heuristic optimization methods provide an effective alternative to structural designs based on experience. The emergence of new materials, structural designs and sustainable criteria motivate the need to create a methodology for the automatic and accurate design of a real post-tensioned concrete bridge that considers all these aspects. For the first time, this thesis studies the efficient design of post-tensioned concrete box-girder road bridges from a sustainable point of view. This research integrates environmental, safety and durability criteria into the optimum design of the bridge. The methodology proposed provides multiple trade-off solutions that hardly increase the cost and achieve improved safety and durability. Likewise, this approach quantifies the sustainable criteria in economic terms, and evaluates the effect of these criteria on the best values of the variables. In this context, a multi-objective optimization is formulated to provide multiple trade-off and high-performing solutions that balance economic, ecologic and societal goals. An optimization design program selects the best geometry, concrete type, reinforcement and post-tensioning steel that meet the objectives selected. A three-span continuous box-girder road bridge located in a coastal region is selected for a case study. This approach provides vital knowledge about this type of bridge in the sustainable context. The life-cycle perspective has been included through a lifetime performance evaluation that models the bridge deterioration process due to chloride-induced corrosion. The economic, environmental and societal impacts of maintenance actions required to extend the service life are examined. Therefore, the proposed goals for an efficient design have been switch from initial stage to life-cycle consideration. Faced with the large computational time of multi-objective optimization and finite-element analysis, artificial neural networks (ANNs) are integrated in the proposed methodology. ANNs are trained to predict the structural response based on the design variables, without the need to analyze the bridge response. The multi-objective optimization problem results in a set of trade-off solutions characterized by the presence of conflicting objectives. The final selection of preferred solutions is simplified by a decision-making technique. A rational technique converts a verbal pairwise comparison between criteria with a degree of uncertainty into numerical values that guarantee the consistency of judgments. This thesis gives a guide for the sustainable design of concrete structures. The use of the proposed approach leads to designs with lower life-cycle cost and emissions compared to general design approaches. Both bridge safety and durability can be improved with a little cost increment by choosing the correct design variables. In addition, this methodology is applicable to any type of structure and material.<br>[ES] Los puentes, como parte importante de una infraestructura, se espera que reúnan todos los requisitos de una sociedad moderna. Tradicionalmente, el objetivo principal en el diseño de puentes ha sido lograr el menor coste mientras se garantiza la eficiencia estructural. Sin embargo, la preocupación por construir un futuro más sostenible ha provocado un cambio en las prioridades de la sociedad. Estructuras más ecológicas y duraderas son cada vez más demandadas. Bajo estas premisas, los métodos de optimización heurística proporcionan una alternativa eficaz a los diseños estructurales basados en la experiencia. La aparición de nuevos materiales, diseños estructurales y criterios sostenibles motivan la necesidad de crear una metodología para el diseño automático y preciso de un puente real de hormigón postesado que considere todos estos aspectos. Por primera vez, esta tesis estudia el diseño eficiente de puentes de hormigón postesado con sección en cajón desde un punto de vista sostenible. Esta investigación integra criterios ambientales, de seguridad estructural y durabilidad en el diseño óptimo del puente. La metodología propuesta proporciona múltiples soluciones que apenas encarecen el coste y mejoran la seguridad y durabilidad. Al mismo tiempo, se cuantifica el enfoque sostenible en términos económicos, y se evalúa el efecto que tienen dichos criterios en el valor óptimo de las variables. En este contexto, se formula una optimización multiobjetivo que proporciona soluciones eficientes y de compromiso entre los criterios económicos, ecológicos y sociales. Un programa de optimización del diseño selecciona la mejor combinación de geometría, tipo de hormigón, armadura y postesado que cumpla con los objetivos seleccionados. Se ha escogido como caso de estudio un puente continuo en cajón de tres vanos situado en la costa. Este método proporciona un mayor conocimiento sobre esta tipología de puentes desde un punto de vista sostenible. Se ha estudiado el ciclo de vida a través de la evaluación del deterioro estructural del puente debido al ataque por cloruros. Se examina el impacto económico, ambiental y social que produce el mantenimiento necesario para extender la vida útil del puente. Por lo tanto, los objetivos propuestos para un diseño eficiente han sido trasladados desde la etapa inicial hasta la consideración del ciclo de vida. Para solucionar el problema del elevado tiempo de cálculo debido a la optimización multiobjetivo y el análisis por elementos finitos, se han integrado redes neuronales en la metodología propuesta. Las redes neuronales son entrenadas para predecir la respuesta estructural a partir de las variables de diseño, sin la necesidad de analizar el puente. El problema de optimización multiobjetivo se traduce en un conjunto de soluciones de compromiso que representan objetivos contrapuestos. La selección final de las soluciones preferidas se simplifica mediante una técnica de toma de decisiones. Una técnica estructurada convierte los juicios basados en comparaciones por pares de elementos con un grado de incertidumbre en valores numéricos que garantizan la consistencia de dichos juicios. Esta tesis proporciona una guía que extiende y mejora las recomendaciones sobre el diseño de estructuras de hormigón dentro del contexto de desarrollo sostenible. El uso de la metodología propuesta lleva a diseños con menor coste y emisiones del ciclo de vida, comparado con diseños que siguen metodologías generales. Los resultados demuestran que mediante una correcta elección del valor de las variables se puede mejorar la seguridad y durabilidad del puente con un pequeño incremento del coste. Además, esta metodología es aplicable a cualquier tipo de estructura y material.<br>[CAT] Els ponts, com a part important d'una infraestructura, s'espera que reunisquen tots els requisits d'una societat moderna. Tradicionalment, l'objectiu principal en el disseny de ponts ha sigut aconseguir el menor cost mentres es garantix l'eficiència estructural. No obstant això, la preocupació per construir un futur més sostenible ha provocat un canvi en les prioritats de la societat. Estructures més ecològiques i durables són cada vegada més demandades. Davall estes premisses, els mètodes d'optimització heurística proporcionen una alternativa eficaç als dissenys estructurals basats en l'experiència. L'aparició de nous materials, dissenys estructurals i criteris sostenibles motiven la necessitat de crear una metodologia per al disseny automàtic i precís d'un pont real de formigó posttesat que considere tots estos aspectos. Per primera vegada, esta tesi estudia el disseny eficient de ponts de formigó posttesat amb secció en calaix des d'un punt de vista sostenible. Esta investigació integra criteris ambientals, de seguretat estructural i durabilitat en el disseny òptim del pont. La metodologia proposada proporciona múltiples solucions que a penes encarixen el cost i milloren la seguretat i durabilitat. Al mateix temps, es quantifica l'enfocament sostenible en termes econòmics, i s'avalua l'efecte que tenen els dits criteris en el valor òptim de les variables. En este context, es formula una optimització multiobjetivo que proporciona solucions eficients i de compromís entre els criteris econòmics, ecològics i socials. Un programa d'optimització del disseny selecciona la millor geometria, tipus de formigó, armadura i posttesat que complisquen amb els objectius seleccionats. S'ha triat com a cas d'estudi un pont continu en calaix de tres vans situat en la costa. Este mètode proporciona un major coneixement sobre esta tipologia de ponts des d'un punt de vista sostenible. S'ha estudiat el cicle de vida a través de l'avaluació del deteriorament estructural del pont a causa de l'atac per clorurs. S'examina l'impacte econòmic, ambiental i social que produïx el manteniment necessari per a estendre la vida útil del pont. Per tant, els objectius proposats per a un disseny eficient han sigut traslladats des de l'etapa inicial fins a la consideració del cicle de vida. Per a solucionar el problema de l'elevat temps de càlcul degut a l'optimització multiobjetivo i l'anàlisi per elements finits, s'han integrat xarxes neuronals en la metodologia proposada. Les xarxes neuronals són entrenades per a predir la resposta estructural a partir de les variables de disseny, sense la necessitat d'analitzar el pont. El problema d'optimització multiobjetivo es traduïx en un conjunt de solucions de compromís que representen objectius contraposats. La selecció final de les solucions preferides se simplifica per mitjà d'una tècnica de presa de decisions. Una tècnica estructurada convertix els juís basats en comparacions per parells d'elements amb un grau d'incertesa en valors numèrics que garantixen la consistència dels dits juís. Esta tesi proporciona una guia que estén i millora les recomanacions sobre el disseny d'estructures de formigó dins del context de desenrotllament sostenible. L'ús de la metodologia proposada porta a dissenys amb menor cost i emissions del cicle de vida, comparat amb dissenys que seguixen metodologies generals. Els resultats demostren que per mitjà d'una correcta elecció del valor de les variables es pot millorar la seguretat i durabilitat del pont amb un xicotet increment del cost. A més, esta metodologia és aplicable a qualsevol tipus d'estructura i material.<br>García Segura, T. (2016). Efficient design of post-tensioned concrete box-girder road bridges based on sustainable multi-objective criteria [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/73147<br>TESIS

Many ageing road bridges, particularly timber bridges, require urgent improvement due to the demand imposed by the recent version of the Australian bridge loading code, AS 5100. As traffic volume plays a key role in the decision of budget allocations for bridge refurbishment/ replacement, many bridges in low volume traffic network remain in poor condition with axle load and/ or speed restrictions, thus disadvantaging many rural communities. This thesis examines an economical and environmentally sensible option of incorporating disused flat rail wagons (FRW) in the construction of bridges in low volume, high axle load road network. The constructability, economy and structural adequacy of the FRW road bridge is reported in the thesis with particular focus of a demonstration bridge commissioned in regional Queensland. The demonstration bridge comprises of a reinforced concrete slab (RCS) pavement resting on two FRWs with custom designed connection brackets at regular intervals along the span of the bridge. The FRW-RC bridge deck assembly is supported on elastomeric rubber pads resting on the abutment. As this type of bridge replacement technology is new and its structural design is not covered in the design standards, the in-service structural performance of the FRW bridge subjected to the high axle loadings prescribed in AS 5100 is examined through performance load testing. Both the static and the moving load tests are carried out using a fully laden commonly available three-axle tandem truck. The bridge deck is extensively strain gauged and displacement at several key locations is measured using linear variable displacement transducers (LVDTs). A high speed camera is used in the performance test and the digital image data are analysed using proprietary software to capture the locations of the wheel positions on the bridge span accurately. The wheel location is thus synchronised with the displacement and strain time series to infer the structural response of the FRW bridge. Field test data are used to calibrate a grillage model, developed for further analysis of the FRW bridge to various sets of high axle loads stipulated in the bridge design standard. Bridge behaviour predicted by the grillage model has exemplified that the live load stresses of the FRW bridge is significantly lower than the yield strength of steel and the deflections are well below the serviceability limit state set out in AS 5100. Based on the results reported in this thesis, it is concluded that the disused FRWs are competent to resist high axle loading prescribed in AS 5100 and are a viable alternative structural solution of bridge deck in the context of the low volume road networks.

Esse trabalho visa a estudar os efeitos dinâmicos provocados por um veículo classe 3C em uma ponte de concreto de seção unicelular, com curvatura em planta, por meio da modelagem do veículo, do pavimento, das forças de interação veículo-pavimento e da estrutura. Partiu-se do modelo do veículo com nove graus de liberdade, considerando o desacoplamento dos esforços longitudinais de interação dos esforços transversais (força de inércia centrífuga). Foram calculados os carregamentos provenientes do veículo modelado, primeiramente sobre tabuleiro rígido indeslocável, considerando as irregularidades geométricas apresentadas no pavimento, com perfis iguais ou distintos sobre cada linha de pneus. Estes carregamentos foram condensados estaticamente e aplicados em um modelo estrutural simplificado (\'unifilar\') de uma ponte em seção unicelular. Utilizou-se um método iterativo para a obtenção dos esforços de interação, até se alcançar a convergência. Ainda foram confrontados resultados para duas situações de tráfego, sendo a primeira para veículo isolado trafegando sobre a estrutura e a segunda para um comboio de veículos. Por fim, as respostas dinâmicas obtidas da interação veículo-estrutura do modelo foram comparadas com uma resposta quase-estática, para a obtenção dos coeficientes de amplificação dinâmica.<br>This dissertation aims at studying the dynamic effects produced by a 3C class vehicle on a curved concrete bridge with box girder section, by modelling the vehicle, the roughness profile, the bridge-vehicle interaction forces and the structure. It started from a model with nine degrees-of-freedom, considering the uncoupling of the longitudinal interaction forces of the transversal forces (centrifugal force of inertia). The loads are evaluated for the vehicle model travelling, firstly on a rigid uneven pavement, considering equal and different roughness profiles under the tires. These loads are statically condensed at the centre of gravity of the car and applied to a simplified (\'unifilar\') structural model of a concrete bridge with box girder section. An iterative method has been used to obtain the interaction forces until the convergence could be achieved. Furthermore, the results for two traffic situations were compared, the first being when a single vehicle is traveling along the structure, whereas the second refers to a train of vehicles. Finally, the dynamic response obtained from the bridge-vehicle interaction was compared with a quasi-static response, allowing for the evaluation of the dynamic amplification coefficients.

Stream crossings are an integral component of forest road systems that provide access for timber harvesting and silvicultural activities. Stream crossings and their associated approaches are often the most critical point of concern for water quality along forest roads. Several types of crossings are used for extracting timber, but limited studies actually compare different types of stream crossings with regard to their effect on water quality. The objectives of this study were to examine four different stream crossing structures: 1) steel bridges, 2) pole bridges (pipe with poles), 3) standard culverts, and 4) re-enforced fords (with GeoWeb or Geotextile) to determine the influence of stream crossing type on water quality and to evaluate erosion associated with stream crossing approaches. We also evaluated each site at four different time intervals to determine if water quality was more affected during different stages of the operations. Prior to operational timber harvests, we identified six replications for each type of crossings (4 fords) and collected data at four time intervals: 1) prior to reopening or installation of crossing, 2) after crossing installation, 3) during harvest operation, and 4) after road closure. Potential erosion rates from approaches to the crossings were estimated by collecting the road/site information necessary to estimate erosion with the Water Erosion Prediction Project for forest roads (WEPP) and the forest version of the Universal Soil Loss Equation (USLE). In-stream water samples were collected at fixed locations above and below each crossing and were evaluated for total dissolved solids (TDS), pH, conductivity, water temperature, and total suspended solids (TSS) or sediment concentration. Steel bridge crossings generally caused the least amount of water quality disturbance. Model-generated estimates of erosion demonstrated that culvert crossings were associated with the highest average soil loss potential. Although steel bridge crossings had the best overall results, pole bridges proved to be a viable option for ephemeral or intermittent streams due to low potential of soil loss. Ford crossings were found to impact water quality indicators, but showed a decrease in total dissolved solids (TDS) after installation, prior to harvest. Overall, the steel skidder bridges were generally the best crossing type, but any of the crossings can be used effectively with minimal impact under specific site conditions and with judicious installation, use, and closure. Road/skid trail location and adherence to existing road grade, water control, cover, and closure best management practices are critical for protection of water quality at stream crossings.<br>Master of Science

<p>Present master of science thesis has been carried out at the Swedish Road Administration consulting services (Vägverket Konsult) in Karlstad. The purpose of the study is to investigate how well the calculated drawdown of the groundwater table predicts the actual drawdown when the road and railway gates at the studied sites are built. For this purpose the groundwater levels at the three bridges were measured during 6 months. The bridges in question are two railway bridges situated in Ölme and Ulvåker and one road bridge crossing a pedestrian and cycling path in Lidköping.</p><p>In Ölme the calculated area of influence was smaller than the measured one. It differed up to 30 meters, i.e. 80 %.</p><p>In Lidköping the calculated area of influence agreed well with the measured one, but the groundwater level that the calculations were made from was more than one meter too low.</p><p>In Ulvåker the measured groundwater levels were influenced by other factors and no conclusions could be drawn.</p><p>When calculating how the groundwater level is affected from road and railway bridge constructions it is important to make sure to measure the groundwater level before the construction is made so that the unaffected level is known. Moreover the radius of the well should be set to a value less than 0.5 meters. It is also important that the conductivity is investigated thoroughly especially for confined aquifers. When measuring groundwater levels the examiner must make sure to plan the distances and depths of the piezometer wells, when to perform the measurements and how to protect the water in the wells from freezing.</p><br><p>Detta examensarbete är utfört på Vägverket Konsult i Karlstad. Syftet med arbetet är att med några exempel undersöka hur väl den beräknade permanenta grundvattensänkningen överensstämmer med den verkliga grundvattensänkning som görs vid byggen av vägportar. Arbetet utfördes genom att under 6 månader mäta grundvattennivåerna vid tre vägportar. De undersökta portarna är en väg – järnvägport i Ölme, en gång- och cykelväg – vägport i Lidköping och en väg – järnvägport i Ulvåker.</p><p>I Ölme framkom att den permanenta grundvattensänkningen har ett större influensområde än den beräknade. Differensen uppgick som mest till 30m vilket motsvarar en avvikelse på ca 80 %.</p><p>I Lidköping överensstämmer beräkningen av influensradierna väl med de uppmätta, medan grundvattennivån som beräkningarna gjordes från ligger drygt en meter för lågt.</p><p>I Ulvåker är den uppmätta avsänkningen påverkad av yttre faktorer och därför kan inga slutsatser dras.</p><p>Vid grundvattensänkningsberäkningar är det viktigt att den opåverkade grundvattennivån är känd, att brunnsradien sätts till ett tal mindre än 0,5 meter och att bestämningen av konduktiviteten är extra noga vid sluten akvifer. När grundvattennivåerna ska mätas bör avstånd och höjdnivå på grundvattenrören bestämmas noga, mätningarna utföras kontinuerligt under en längre tid och eventuell tillsats av frostskydd i grundvattenrören tänkas igenom.</p>

O Brasil, um país de dimensões continentais e inúmeros rios em seu território, tem uma enorme carência de pontes para pequenos e médios vãos. Atualmente, a elevada produção de madeira de reflorestamento traz à engenharia uma opção de material renovável e ecologicamente correto para se utilizar em prol do ser humano nas obras de infraestrutura, mais especificamente na construção de pontes, uma vez que a madeira possui ótimo desempenho quando sujeita a cargas de curta duração. A utilização de Madeira Laminada Colada (MLC) permite a fabricação de peças de grandes dimensões, com excelente estabilidade, e com elevado controle de qualidade, proporcionando segurança e confiabilidade à estrutura. Este trabalho tem como objetivo o estudo teórico de pontes em vigas de MLC e tabuleiros em painéis de MLC utilizando procedimentos desenvolvidos por pesquisadores internacionalmente renomados e adequando estes procedimentos para as normas e condições brasileiras. Apresentam-se neste trabalho tabelas para pré-dimensionamento deste tipo de ponte para vãos de 8m a 20m para TB-30 e TB-45. Além disso, analisam-se numérica e experimentalmente os ganhos de rigidez e redução de deslocamentos relativos proporcionados pela utilização de vigas de enrijecimento, bem como a influência da seção destas vigas e a quantidade de parafusos utilizados para interligar ao tabuleiro. Por fim, apresentam-se algumas disposições construtivas não estruturais fundamentais para o bom funcionamento deste tipo de estrutura.<br>Brazil, a continental size country and with many rivers in its territory, has a huge necessity for short and medium spans bridges. Nowadays, the high production of reforestation wood allows to engineering an option of renewable material and ecologically correct to be used in favor to humans in infrastructure works, most specifically in bridges construction, once timber has a great performance in quick loads. The use of Glued-Laminated Timber (Glulam) enable the manufacture of large sizes members, with excellent stability, and a high control of quality in its production, providing a safety and reliability structure. This work aim the theoretical study of glulam stringers bridge and glulam panels deck using procedures developed by international researchers and adapting those procedures for Brazilian conditions and normalizations. Pre-design tables are presented in this work for 8m to 20m spans for TB-30 and TB-45. In addition to, analyses numerical and experimentally the gain of stiffness and the reduction of relative displacements between panels provided by the use of stiffener beams, besides the influence of those beams section size and number of bolts used for deck interconnection. Finally, it is presented some not structural constructive arrangements essential for good performance of this kind of structure.

[Abstract]Over the last few decades, there has been a rapid increase in the volume and weight of heavy vehicles using national road networks. More than half of the bridges around the world are over forty years old. The deterioration of these existing bridges due to increased traffic loading, progressive structural aging, and reinforcement corrosion from severe environmental conditions has become a major problem in most countries. Several techniques have been used to strengthen these structures around the world. External post-tensioning is one of the widely used strengthening techniques in many countries due to its advantages over other methods. Furthermore, flexural strengthening using external post-tensioning has become a well established technique over the past few decades. However, when external post-tensioning is used to strengthen shear damaged reinforced concrete members, unlike flexural damage, the efficiency is significantly reduced by existing shear cracks.This research study was carried out to investigate the behaviour of reinforced concrete beams with existing shear cracks when strengthened by external means. The study consists of two parts: experimental investigations of reinforced concrete beams with different parameters and numerical analysis of reinforced concrete beams usingsimplified theoretical formulation and finite element modelling.To study the behaviour of shear damaged concrete beams, two different strengthening techniques, namely external post-tensioning and external clamping, were used. In addition to the strengthening, the effect of cracks on the behaviour of reinforced concrete beams was investigated by repairing such cracks using epoxy resin injection. Experimental results showed that existing shear cracks have a substantial effect on the member capacity when strengthened by external posttensioning. Although there are concerns about the practical applications of externalclamping, the experimental results suggest that external clamping could be a more effective technique than external post-tensioning to reduce the effect of existing shear cracks on the behaviour of concrete beams. Furthermore, proper repair of the shear cracks could significantly reduce their impact.In the numerical analysis, a simplified mathematical approach was developed to estimate the capacity of shear damaged reinforced concrete beam by expanding themodified compression field theory (MCFT). In addition to the simplified theoretical formulation, a finite element model was developed using the commercial finite element package, Abaqus. Comparison between the predicted behaviour using finite element analysis (FEA) and the experimental data illustrated that the developed finite element model could be used as a reliable tool to estimate the capacity of shear damaged reinforced concrete beams. A parametric study was conducted to investigate the effect of different parameters such as concrete strength, amount of shear reinforcement and crack width, using the developed finite element model. From the numerical study, it was concluded that the simplified approach developedin this study can be used as a reliable and conservative technique to predict the member capacity of a cracked reinforced concrete beam strengthened by external means. Furthermore, the parametric study showed that crack width is the most sensitive parameter that affects the capacity of a cracked beam strengthened by external post-tensioning.Based on this research study it can be concluded that existing shear cracks have a substantial effect on the behaviour of reinforced concrete beams strengthened byexternal post-tensioning. The simplified mathematical approach developed in this study can be used to estimate the capacity of such beams.

La sicurezza dei sistemi infrastrutturali è di fondamentale importanza per la società. Malfunzionamenti, danni o crolli possono avere notevoli impatti socioeconomici e ripercussioni sulla sicurezza pubblica. Secondo l’approccio classico, l'analisi della vulnerabilità dei ponti viene condotta attraverso l'adozione di curve di fragilità, che esprimono la probabilità di superamento di un certo livello di prestazione condizionata ad un determinato livello di intensità della fonte di pericolo. Tuttavia, è pratica comune utilizzare le curve di fragilità per fornire solo una panoramica globale della vulnerabilità del ponte, con scarsa attenzione all'estensione del danno o all'evoluzione dei diversi meccanismi che possono verificarsi all'interno della struttura. Infatti, vale la pena notare che i ponti possono mostrare diversi meccanismi di danno; in base a quali e quanti componenti strutturali sono coinvolti, essi contribuiscono in modo diverso alla fragilità complessiva del sistema e potenzialmente portano a diversi scenari post-disastro. Considerando quindi che ad oggi non è ancora disponibile un framework probabilistico completo e robusto per la valutazione del rischio, la presente Tesi fornisce alcuni contributi originali per un arricchimento dello stato dell’arte nel campo della sicurezza dei sistemi infrastrutturali. I principali obiettivi perseguiti nella Tesi sono i seguenti: sviluppo di un approccio innovativo per la descrizione e quantificazione probabilistica del danno sismico atteso sui ponti esistenti; analisi degli effetti dell’interazione terreno-struttura attraverso la proposta di formulazioni semplificate per la stima del comportamento di fondazioni su pali (comuni per le strutture da ponte) e di facile implementazione per un’ analisi affidabile della fragilità e del rischio; proposta di un framework omnicomprensivo per la valutazione del rischio e la quantificazione delle conseguenze di eventi sismici in termini economici, tenendo conto di aspetti quali l’interazione terreno-struttura, il degrado e gli interventi manutentivi; analisi degli effetti delle incertezze che interessano il sistema pali-terreno per la caratterizzazione probabilistica delle funzioni di impedenza e dei fattori di risposta cinematica di fondazioni profonde in sottosuoli omogenei. Il sistema trasportistico italiano è stato scelto per le applicazioni della presente Tesi, in quanto emblematico per l'elevata vulnerabilità e le importanti criticità presentate dalle reti stradali esistenti. Si considerano due diverse tipologie di ponti: catena cinematica in calcestruzzo armato e sezione composta acciaio-calcestruzzo. Tali tipologie risultano rappresentative della maggior parte dei ponti e viadotti presenti sul territorio italiano, ed esempi si possono trovare anche nel panorama internazionale. La scelta di casi studio significativi consente di mostrare le potenzialità delle metodologie proposte e la rilevanza del problema di interazione terreno-struttura nella valutazione della vulnerabilità, nonché di caratterizzare la vulnerabilità delle infrastrutture italiane con un livello di dettaglio più elevato, includendo fenomeni di degrado e interazione, il tutto all’interno di un approccio probabilistico. Inoltre, la scelta delle configurazioni strutturali risulta adatta per la caratterizzazione di uno scenario regionale, come quello marchigiano. I risultati dello studio di fragilità vengono quindi applicati a livello di rete stradale per la quantificazione dell'impatto degli scenari post-terremoto in termini economici. Sebbene presentate per il problema sismico e nel contesto italiano, le metodologie proposte sono abbastanza flessibili da essere facilmente applicate ad ulteriori scenari infrastrutturali (ed altre tipologie di ponti) e a diverse fonti di pericolo (frane, alluvioni, ecc.).<br>The safety of infrastructural systems is of paramount importance since high socio-economic impacts on the society would be expected in case of disruptions or people life could be seriously endangered in case of severe damages or collapses. The analysis of the vulnerability of bridges is classically carried out through the adoption of fragility curves, which express the probability of exceedance of a certain performance level conditional to a certain level of hazard intensity. However, it is common practice to use fragility curves to only provide a global overview of the bridge vulnerability, with scarce attention to the damage extension or the evolution of different failure mechanisms that may potentially verify within the structure. Indeed, it is worth noting that bridges may show different damage mechanisms, occurring in one or multiple structural components, that differently contribute to the overall fragility of the system and potentially lead to different post-disaster scenarios. In light of this drawback and considering also that an optimal, comprehensive and robust probabilistic framework for the risk assessment is not yet available, the present Thesis aims to provide some insights and original contributions for a state-of-the-art enrichment in the field of the safety of infrastructural systems. Advancements are indeed made on the following main subjects: fragility curves, with an innovative approach for a proper estimation of the bridge vulnerability, based on both a quantitative and qualitative assessment of failure mechanisms that may occur during a seismic event; analysis of Soil-Structure Interaction (SSI) effects through simple formulas estimating the behaviour of pile foundations (a common choice in case of bridge structures) and easy to be implemented for a reliable fragility and risk analysis; proposal of a holistic framework for the risk assessment and the quantification of consequences of a hazardous event in monetary terms, taking into account aspects such as SSI, degradation and maintenance; analysis of the effects of uncertainties affecting the combined pile-soil system for the probabilistic characterization of impedance functions and kinematic response factors of deep foundations in homogeneous soils. The Italian transport system is chosen as scenario for the applications of the present Thesis, since it is particularly emblematic due to the high vulnerability and the important critical issues presented by the existing road networks. Two different bridge typologies are considered: Reinforced Concrete Link Slab bridges and Steel-Concrete Composite bridges. Being very widespread, such typologies result representative of most of the bridges and viaducts present over the Italian territory, and examples can also be found in the international panorama. The choice of significative case studies allows to prove the potentialities of the proposed fragility estimation methodology and the relevance of the SSI problem in the bridge vulnerability assessment as well as to characterise the vulnerability of the Italian infrastructures with a higher level of detail, including degradation and SSI phenomena. Moreover, the choice of structural configurations is suitable for the characterization of a regional scenario, such as the one of Marche region. Then, fragility results are applied at road network level for the quantification of the impact of post-earthquake scenarios in economic terms throughout the proposed probabilistic framework. Finally, as part of the framework, a novel probabilistic characterization of the response of deep foundations in homogeneous soil is provided to evaluate effects of uncertainties in the embedded system. Although presented for the seismic problem and within the Italian context, the proposed methodologies are flexible enough to be easily extended to further applications involving other road network scenarios (and bridge typologies) and different natural hazards.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Considerando-se os diversos carregamentos que solicitam a estrutura de uma ponte rodoviária, ao longo de sua vida útil, alguns possuem um comportamento essencialmente dinâmico, ou seja, variam com o tempo, diferentemente do que é considerado na prática corrente de projeto desse tipo de obra de arte. Em geral, os projetistas desse tipo de estrutura têm tratado carregamentos como o de vento, tráfego de veículos e de pedestres como ações de natureza estática, ignorando seu perfil cíclico. Tal consideração, em diversas situações de projeto, tende a minorar os efeitos das ações dinâmicas sobre o sistema estrutural. Além disso, estruturas submetidas a solicitações cíclicas, sob uma carga inferior à caga máxima suportada pelo material, estão sujeitas ao fenômeno da fadiga. A consideração adequada de todos estes aspectos mostra-se fundamentalmente importante para correta avaliação dos níveis de esforços solicitantes do sistema estrutural e, bem como, para a identificação de fenômenos importantes como o da fadiga que pode vir a provocar, por exemplo, a ruptura de componentes estruturais sem aviso prévio ou motivo aparente. Para tal, nesta dissertação as técnicas para a contagem de ciclos de tensão e a aplicação das regras de dano acumulado foram analisadas através de curvas do tipo S-N, associadas a diversas normas de projeto. A ponte rodoviária mista (aço-concreto) investigada neste estudo é constituída por seis vigas de aço longitudinais com enrijecedores transversais, oito transversinas e por um tabuleiro de concreto armado. O modelo numérico-computacional, desenvolvido para a análise dinâmica da ponte, foi elaborado com base em técnicas usuais de discretização através do método dos elementos finitos. As mesas e almas das vigas, assim como os enrijecedores , foram modelados por elementos de casca e laje de concreto armado, por elementos sólidos. O carregamento dinâmico avaliado no presente estudo diz respeito ao tráfego de veículos, cuja representação se dá a partir de sistemas "massa-mola-amortecedor". Os comboios formados são adotados como sendo semi-infinitos, deslocando-se com velocidade constante sobre a ponte. As conclusões da presente investigação versam acerca da vida útil de serviço dos elementos estruturais de pontes mistas (aço-concreto).<br>Considering the various shipments requesting the structure of a road bridge over its useful life, some are of an essentially dynamic behavior, ie , vary with time, contrary to what is considered standard practice in the design of this type of work of art. In general, the designers of this type of structure have treated loads such as wind, vehicles and pedestrians as traffic static nature of actions, ignoring their cyclical profile. This consideration, in various design situations, tends to mitigate the effects of dynamic actions on the structural system. Furthermore, structures subjected to cyclic requests under a lower load at maximum shits supported by the material, are subject to fatigue phenomenon. The proper consideration of these aspects is shown fundamentally important for accurate assessment of levels of internal forces in the structural system, as well as for the identification of important phenomena such as fatigue which may ultimately lead, for example, disruption of structural components without warning or apparent reason. To this end, this dissertation techniques for counting cycles of tension and enforcement of accumulated damage were analyzed by the type SN curves associated with various design standards. Mixed road bridge (steel-concrete) investigated in this study consists of six longitudinal steel girders with transverse stiffeners eight crossbeams and a deck of reinforced concrete. The numerical - computational model developed for the dynamic analysis of the bridge, was based on standard techniques of discretization by finite element method. The tables and souls of the beams, as well as the stiffeners were modeled by shell elements and reinforced concrete slab, for solid elements. The dynamic loading evaluated in this study relates to vehicular traffic, whose representation is given from "mass - spring - damper systems." Trains formed are adopted as semi - infinite, moving with constant speed on the bridge. The findings of this research Versam about the service life of the structural elements of composite (steel-concrete) bridges.

Two critical components of the United States civil infrastructure, bridges and roads, have deteriorated in the past two decades at an accelerated rate and are in need of maintenance and rehabilitation. Geosynthetics may have the potential to provide a long-term solution to some of the problems that are present in these roads and bridges. When installed properly, some geosynthetics can act as both a moisture barrier and stress absorption layer. However, the tack coat application rate is critical as an excessive amount can cause eventual slippage, while too little may result in debonding. A new geocomposite membrane, which is comprised of a low modulus PVC layer sandwiched between two layers of nonwoven geotextile, has recently been introduced for use in highway systems for water impermeability and strain energy absorption. A laboratory testing program was conducted to determine the optimum asphalt binder tack coat rate that needs to be applied in the field. To accomplish this, a fixture was designed to allow the application of cyclic shear loading at the geocomposite membrane interface when used as an interlayer simulating one of two situations: a concrete bridge deck overlaid with the geocomposite membrane, and an HMA overlay or a flexible pavement with the geocomposite membrane sandwiched between an HMA base layer and an HMA wearing surface. The research concluded that 1.40 kg/m2 of tack coat should be used when the geocomposite surface is in contact with an HMA base mix, 1.5 kg/m2 should be used when it is in contact with an HMA surface mix, and 1.75 kg/m2 should be used when it is in contact with concrete surfaces. However, these tack coat application rates are a function of the structural material type and the tack coat material type (binder performance grade). In addition, an analysis of the simulated bridge deck specimens with geocomposite membrane and the control samples, containing no membrane, shows distinct evidence that the membrane acts as a stress-absorbing material.<br>Master of Science

This thesis examines the physical evidence for ancient bridges and roads in the three most eastern provinces of the Roman Empire. Its focus is the two and a half centuries before the Arab invasions when population reached a peak. It uses satellite photographs from Google Earth to place the roads in a geographical context and contains many maps. The thesis describes twenty-four stone bridges in the provinces concerned which are thought to date from the Roman period and contains photographs of these where possible. Field research has included a large number of visits to SE Turkey and two visits to Syria. On the basis of the material evidence and the ancient sources, in particular the Peutinger Table (which are discussed in a specific chapter), the thesis examines the course of the roads and their users; it also addresses the reasons for construction of the roads, together with associated issues such as the disappearance of wheeled vehicles. The thesis describes the ancient cities, the settlement pattern and the fortifications of this region, which lay on a much troubled frontier with frequent warfare between Rome and Persia. It discusses how warfare and the construction of fortifications modified the nature of the region in the sixth century AD and then examines issues arising from the existence of the road network such as defence of the frontier, trade and the impact that commercial and social links, as well as the road network itself, had on relations between the two great empires of Late Antiquity. Annexes short reviews of archaeological work in the area and of medieval and modern travellers who have passed through it. A gazetteer of cities and fortresses mentioned in the text is attached at the end.

A presente dissertação debruça-se sobre a formação e configuração da "cidade difusa" que caracteriza a aglomeração urbana do Porto e o modo como se manifesta no território analisando, por um lado, os factores indutores dessa dispersão e, por outro, reconhecendo os efeitos de catálise urbana produzidos pelo enclave de estruturas urbanas de excepção (após década de 60). Escolheu-se para estudo de cas, a mancha difusa envolvente do nó rodoviário da Afurada, em Vila Nova de Gaia, tornando assim mais clara, a articulação das questões morfológicas e funcionais com os tecidos que compõem este território, tendo sempre presente as questões de acessibilidade e mobicilidade acrescidas que tanto o nó rodoviário como as vias estruturantes metropolitanas introduziram naquele local. Reconhecemos, assim, que efeitos de centralidade e nucleação urbana revelam-se potenciais intensificadores dos processos de transformação urbana e da sua vasta e benéfica diversidade.

A presente dissertação debruça-se sobre a formação e configuração da "cidade difusa" que caracteriza a aglomeração urbana do Porto e o modo como se manifesta no território analisando, por um lado, os factores indutores dessa dispersão e, por outro, reconhecendo os efeitos de catálise urbana produzidos pelo enclave de estruturas urbanas de excepção (após década de 60). Escolheu-se para estudo de cas, a mancha difusa envolvente do nó rodoviário da Afurada, em Vila Nova de Gaia, tornando assim mais clara, a articulação das questões morfológicas e funcionais com os tecidos que compõem este território, tendo sempre presente as questões de acessibilidade e mobicilidade acrescidas que tanto o nó rodoviário como as vias estruturantes metropolitanas introduziram naquele local. Reconhecemos, assim, que efeitos de centralidade e nucleação urbana revelam-se potenciais intensificadores dos processos de transformação urbana e da sua vasta e benéfica diversidade.

The diploma thesis deals with design and assessment of steel arched bridge with the semi through bridge deck placed on the third-class road. This steel structure is drawn up to bridge water barrier – the river Olše in Návsí. The distance between axes lay on abutments is 48,5 meters. The bridge´s supporting structure consists of two steel arches angled towards each other and fastened to the foundation blocks. The supporting beam of the bridge deck is tied to the arch by tie-rods. The tie-rods are designed to the V-shaped system.

This thesis solves design of intrchange R 46 and II/428 near Vyškov, more exactly specified in the village Drysice. In the existing situation is not resolved connecting lanes and turning lanes at the interchange. This causes reduced road safety, which leads to a significant number of traffic accidents in this section. The thesis solves design respectively modification substandard connecting and turning lanes on all parts of flyover crossroads with associated modifications of two bridges. Integral part of the proposed modification is the elimination of existing noise load in the village, by using of noise barriers.

Structural health monitoring (SHM) using ambient vibration has become a tool in evaluating and assessing the condition of civil structures. For bridge structures, a vibration-based SHM system uses the dynamic response of a bridge to measure modal parameters. A change in a structure’s modal parameters can indicate a physical change in the system, such as damage or a boundary condition change. These same modal parameters are sensitive to environmental factors, mainly temperature. Statistical models have been utilized to filter out modal parameter changes influenced by temperature and those caused by physical changes. Statistical models also help describe the relationship between modal parameters and environmental conditions. The Lambert Road Bridge is a concrete integral abutment bridge located south of Sacramento, California, and is studied through this paper. A SHM system has been installed and has been recorded for 3 years. Three months of SHM records will be used to understand how the bridge’s natural frequencies typically change due to temperature. First, temperature was observed to be the driving force behind many of the SHM records. A linear relationship was found between the structure’s natural frequency and temperature. Collinearities between potential predictor variables were noticed. Initial linear regression analyses were completed with a bridge average temperature. Certain strain gauge regression models were used as “base” models to eliminate other regression models that potentially were altered by aliasing. These base models, and the other seven corresponding models, showed a direct linear relationship between temperature and natural frequency. It was concluded that changes in boundary conditions due to bridge expansion have a greater effect on global dynamic properties than material property changes due to temperature. Stepwise linear regression followed the initial regression modeling. Eight thermocouple readings were consistently being selected in the stepwise process and were chosen to be the main predictor variables. Due to collinearities among the predictor variables, ridge regression was completed to eliminate any unstable variables. The final six sensors’ locations indicate that longitudinal, transverse, and depth gradients are all important factors in the linear regression models of this relationship. Comparing the multiple linear regression models to single-variable regression models with the highest averaged adjusted R2 values, a minimum percent difference of 21% and 19% was seen for the first and second natural frequencies, respectively. It was also concluded that these multiple linear regression models explained more of the variability in the natural frequencies and would be a better model to use to filter out temperature effects.

We evaluated the influence of a landscape dominated by agriculture and an extensive road network on fine-scale movements of black bears (Ursus americanus) in south-central Florida. The objectives of this study were to (1) define landscape functionality including corridor use by the directionality and speed of bear movements, (2) to develop a model reflecting selected habitat characteristics during movements, (3) to identify habitat characteristics selected by bears at road-crossing locations, and (3) to develop and evaluate a predictive model for road-crossing locations based on habitat characteristics. We assessed models using GPS data from 20 adult black bears (9 F, 11 M), including 382 unique road-crossing events by 16 individuals. Directionality of bear movements were influenced by the density of cover and proximity to human infrastructure, and movement speed was influenced by density of cover and proximity to paved roads. We used the Brownian bridge movement model to assess road-crossing behavior. Landscape-level factors like density of cover and density of roads appeared more influential than roadside factors, vegetative or otherwise. Model validation procedures suggested strong predictive ability for the selected road-crossing model. These findings will allow managers to prioritize and implement sound strategies to promote connectivity and reduce road collisions.

This research is part of a major project with a stimulus that rose from the need to manage a large number of ageing bridges in low traffic volume roads (LTVR) in Australia. The project investigated, designed and consequently constructed, involved replacing an ageing super-structure of a 10m span bridge with a disused Flat-bed Rail Wagon (FRW). This research, therefore, is developed on the premises that the FRW can be adopted as the main structural system for the bridges in LTVR network. The main focus of this research is to present two alternate deck wearing systems (DWS) as part of the design of the FRW as road bridge deck conforming to AS5100 (2004). The bare FRW structural components were first examined for their adequacy (ultimate and serviceability) in resisting the critical loads specified in AS5100(2004). Two options of DWSs were evaluated and their effects on the FRW examined. The first option involved usage of timber DWS; the idea of this option was to use all the primary and secondary members of the FRW in load sharing and to provide additional members where weaknesses in the original members arose. The second option involved usage of reinforced concrete DWS with only the primary members of the FRW sharing the AS5100 (2004) loading. This option inherently minimised the risk associated with any uncertainty of the secondary members to their structural adequacy. This thesis reports the design phases of both options with conclusions of the selection of the ideal option for better structural performance, ease of construction and cost. The comparison carried out here focuses on the distribution of the traffic load by the FRW as a superstructure. Advantages and disadvantages highlighting cost comparisons and ease of constructability of the two systems are also included.

For health and safety monitoring in civil constructions such as bridges, roads and pavements, segmenting the regions of interest is the fundamental requirement for image analysis at high-level semantic. One of the major structural problems in concrete and asphalt surfaces are cracks, which start with harming the visual aspect of the construction and further lead to failure of the construction. This study makes four contributions to extract the image foreground from the background in order to address the crack detection task on the asphalt and concrete surfaces. Specifically, we model cracks as foreground objects and concrete or asphalt surfaces as textured background. The first contribution of this research is a hybrid image processing method for crack detection. In this method, the cracks are modelled as linear structures on the background of textured concrete or asphalt surfaces, which can be extracted by combining structure extraction with global pattern distribution. There are two phases in this model towards creating the final structure-texture map. The first phase is extracting strong structures or edges using relative total variation measures, which produces a structure feature map by preserving the edges and suppressing the background noises. The second phase calculates the spatial distribution of textures across the image. A bag-of-words model is used in this phase to quantise the texture pattern, which in crack detection application is the widely distributed road texture background. The local structure map and the global distribution map extract the crack structure and the textured background, respectively. The final crack is extracted by fusing these two maps and applying binarisation as the post-processing step. This model achieved a better result compared with the local structure extraction and the saliency method. As the second contribution, a large-scale dataset of asphalt and concrete crack images is prepared, including images with their corresponding high-resolution pixel-wise labels. To the best of our knowledge, until the completion of this thesis, there has not been any crack image dataset with pixel-wise ground truth labels available. The original crack image set includes 2532 images of cracks on brick and asphalt surfaces. This image set is split into training, validation and testing sets with the ratio of 50/25/25. Two augmentation techniques of rotation and ipping are applied to only the training set while validation and testing sets are locked in order to prevent the data leakage. All models are learned on the training set after fine-tuning the hyper-parameters. After each tuning, an early estimate of the model accuracy is obtained using the validation set. Finally, an unbiased performance estimation of the fitted model is provided on the testing set. The third contribution of this thesis is developing two encoder-decoder networks by exploring the recent advances of deep learning research for crack detection and applying them on our crack dataset. The first network is inspired by DeepLab, which is a modified ResNet architecture. In this network the last pooling layer is replaced with an Atrous Spatial Pyramid Pooling (ASPP) module. This encoder-decoder structure is designed to classify each image pixel into two foreground cracks or textured background. The second model is inspired by Full Resolution Residual Network (FRRN), which is a ResNetlike network with two residual and pooling streams to extract the high- and low-level features, respectively. The combination of di erent level features in this model improves the localization of crack pixels as well as the recognition of the crack structure as a whole. As FRRN outperforms DeepLab on crack classification, we select it as the baseline for further research. In our last contribution, we optimise the FRRN model by reducing the number of parameters. Inspired by the Inception module which significantly improved the utilization of the computing resources inside the GoogLeNet, we proposed Incepted FRRN (I-FRRN) network by embedding the Inception module inside the FRRN. Combining these two structures, our proposed model records 88.14% accuracy in classifying the positive class with 0.22% improvement, while having less than half the number of parameters compared with FRRN. The results show that the proposed architecture achieves significant computational e ciency gains and comparable or higher class-accuracy in crack classification task over the baseline model.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Info & Comm Tech<br>Science, Environment, Engineering and Technology<br>Full Text

[ES] Las inundaciones pueden llegar a desestabilizar los vehículos y estos, a su vez, pueden exacerbar los efectos negativos de las inundaciones cuando son arrastrados por el flujo, generando no solamente pérdidas económicas sino también de vidas humanas. En las ciudades, la mayor parte de las muertes durante las inundaciones ocurre al interior de los vehículos debido a que los conductores intentan cruzar con sus vehículos por zonas inundadas (Jonkzman and Kelman 2005; Drobot et al. 2007; Kellar and Schmidlin 2012). En países desarrollados, un alto porcentaje de estas muertes ocurre durante inundaciones relámpago cuando los conductores intentan cruzar por zonas inundadas en lugar de evitarlas (Fitzgerald et al. 2010; Kellar y Schmidlin 2012). Debido a esto, en áreas sujetas a inundaciones relámpago, casi la mitad de las víctimas son pasajeros atrapados en sus vehículos (Versini et al. 2010a) Entre las partes de las vías que resultan afectadas por las crecidas de los ríos se encuentran los puentes, las cuales son obras de infraestructura muy importantes. Un alto porcentaje de los fallos de los puentes a nivel mundial se presenta debido a las crecidas de los ríos, lo cual tiene un impacto negativo en los vehículos y los sistemas de transporte. Debido a esto, con el fin de realizar una adecuada gestión de las inundaciones es necesario determinar el riesgo de inestabilidad al que están sometidos los vehículos en una zona inundable. Sin embargo, a pesar del impacto negativo de las inundaciones, hasta la fecha se dispone de pocos estudios que permitan determinar los efectos negativos que las condiciones climáticas generan sobre los sistemas de transporte (Molarius et al., 2014). En esta investigación se desarrolló una nueva metodología para calcular este riesgo a partir de las características de las crecidas, los puentes, los vehículos, y el tráfico vehicular. Esta metodología fue generada a partir de una estructura conceptual y un desarrollo matemático novedosos y permite determinar el riesgo a través de la integral estadística de la amenaza de inestabilidad y la vulnerabilidad de los coches. En áreas urbanas y en las intersecciones entre las corrientes de agua y las vías, la amenaza se establece a través de una función de estabilidad de autos parcialmente sumergidos, las características geométricas de los vehículos y las características hidrodinámicas de las crecidas (calados y velocidades) y su probabilidad de ocurrencia, mientras que la vulnerabilidad se calcula por medio de la combinación de la susceptibilidad y la exposición de los coches. En puentes, la peligrosidad se obtiene a través del análisis de los datos de caudal disponibles y la vulnerabilidad mediante el análisis del estado estructural del puente, las características de la cuenca y del cauce aguas arriba y aguas abajo de la estructura, la estabilidad del canal y la potencial acumulación de acarreos. La metodología desarrollada se implementó para determinar el riesgo en los siguientes casos de estudio, los cuales están localizados en territorio español: (i) en las áreas urbanas correspondientes a los municipios de Alfafar y Massanassa, (ii) en los sitios de intersección entre vías y ríos localizados en el municipio de Godelleta; y (iii) en 12 puentes fluviales. Los resultados obtenidos podrían estar indicando que el método propuesto tiene en cuenta los elementos más importantes que deben considerarse al establecer este tipo de riesgo. La metodología desarrollada permite obtener un panorama detallado del riesgo de desestabilización de los vehículos debido a inundaciones en una zona determinada. En consecuencia, la implementación de esta metodología puede ayudar a disminuir los efectos negativos antes y durante este tipo de eventos, resultando de gran ayuda para las entidades encargadas de la planificación urbana y de la protección civil con el fin de diseñar e implementar acciones que permitan disminu<br>[CAT] Les inundacions poden desestabilitzar els vehicles i aquests, al mateix temps, poden exacerbar els efectes negatius de les inundacions quan són arrossegats pel flux, generant no solament pèrdues econòmiques sinó també de vides humanes. A les ciutats, la major part de les morts durant les inundacions ocorre a l'interior dels vehicles pel fet que els conductors intenten creuar amb els seus vehicles per zones inundades (Jonkzman and Kelman 2005; Drobot et al. 2007; Kellar and Schmidlin 2012). En països desenvolupats, un alt percentatge d'aquestes morts ocorre durant inundacions llampec quan els conductors intenten creuar per zones inundades en lloc d'evitar-les (Fitzgerald et al. 2010; Kellar i Schmidlin 2012). A causa d'això, en àrees subjectes a inundacions llampec, quasi la meitat de les víctimes són passatgers atrapats en els seus propis vehicles (Versini et al. 2010a) Entre les parts de les vies que resulten afectades per les crescudes dels rius es troben els ponts, les quals són obres d'infraestructura molt importants. Un alt percentatge de les fallades dels ponts a nivell mundial es presenta com a conseqüència de les crescudes dels rius, la qual cosa té un impacte altament negatiu en els vehicles i els sistemes de transport.. A causa d'això, amb la finalitat de realitzar una adequada gestió de les inundacions és necessari determinar el risc d'inestabilitat al qual estan sotmesos els vehicles en una zona inundable. No obstant això, malgrat l'impacte negatiu de les inundacions, fins a la data es disposa de pocs estudis que permeten determinar els efectes negatius que les condicions climàtiques generen sobre els sistemes de transport (Molarius et al., 2014). En la present investigació es va desenvolupar una nova metodologia per a calcular aquest risc a partir de les característiques de les crescudes, els ponts, els vehicles, i el trànsit vehicular. Aquesta metodologia va ser generada a partir d'una estructura conceptual i un desenvolupament matemàtic nous i permet determinar el risc a través de la integral estadística de l'amenaça d'inestabilitat i la vulnerabilitat dels cotxes. En àrees urbanes i en les interseccions entre els corrents d'aigua i les vies, l'amenaça s'estableix a través d'una funció d'estabilitat de cotxes parcialment submergits, les característiques geomètriques dels vehicles i les característiques hidrodinàmiques de les crescudes (calats i velocitats) i la seua probabilitat d'ocurrència, mentre que la vulnerabilitat es calcula per mitjà de la combinació de la susceptibilitat i l'exposició dels cotxes. En ponts, la perillositat s'obté a través de l'anàlisi de les dades de cabal disponibles i la vulnerabilitat mitjançant l'anàlisi de l'estat estructural del pont, les característiques de la conca i del llit aigües amunt i aigües avall de l'estructura, l'estabilitat del canal i la potencial acumulació d'enderrocs. La metodologia desenvolupada es va implementar per a determinar el risc en els següents casos d'estudi, els quals estan localitzats en territori espanyol: (i) en les àrees urbanes corresponents als municipis d'Alfafar i Massanassa, (ii) en els llocs d'intersecció entre vies i rius localitzats en el municipi de Godelleta; i (iii) en 12 ponts fluvials. Els resultats obtinguts podrien estar indicant que el mètode proposat té en compte els elements més importants que han de considerar-se en establir aquest tipus de risc. La metodologia desenvolupada permet obtindre un panorama detallat del risc de desestabilització dels vehicles a causa d'inundacions en una zona determinada. En conseqüència, la implementació d'aquesta metodologia pot ajudar a disminuir els efectes negatius abans i durant aquesta mena d'esdeveniments, resultant de gran ajuda per a les entitats encarregades de la planificació urbana i de la protecció civil amb la finalitat de dissenyar i implementar accions que permeten disminuir els efectes negatius de les inundacions.<br>[EN] Flooding can destabilize vehicles which might, in turn, exacerbate the negative effects of floods when vehicles are swept away by flows, leading to economic loss and fatalities. The main cause of death in cities during flood events corresponds to cars being swept away when they are driven by flooded roads (Jonkzman and Kelman 2005; Drobot et al. 2007; Kellar and Schmidlin 2012). In developed countries a high percentage of these deaths occurs during flash floods when drivers try to cross overflowing water bodies instead of avoiding them (Fitzgerald et al. 2010; Kellar and Schmidlin 2012). Hence, in areas subject to flash floods almost half of the victims are passengers trapped inside their own vehicles (Versini et al. 2010a). Among the parts of the roads that are most affected by floods are bridges, which are very important infrastructure works for society. Because of this, a high percentage of bridge failures worldwide occur as a result of river floods, which has highly negative impacts for vehicles and transportation systems. Therefore, in order to suitably manage floods, it is necessary to determine the risk of instability to which vehicles in flood-prone areas are subject. However, Despite the negative impact of floods, very few studies have centred on determining the negative effects of floods on transport systems (Molarius et al., 2014). In this research, a new methodology to estimate this risk based on the characteristics of vehicles, floods, bridges and vehicular traffic was developed. This methodology was generated from a novel conceptual structure and mathematical development and allows to determine the risk by the statistical integral of the instability hazard and the vehicles' vulnerability. In urban areas and stream crossings, the hazard is determined by a stability criterion of partially submerged cars, the geometric characteristics of the vehicles and the hydrodynamic characteristics of the floods (depths and velocities) and their probability of occurrence, while vulnerability is calculated by combining the susceptibility and exposure of cars. In bridges, the hazard is obtained by analysing available discharge data and the vulnerability by examining the structural condition of the bridge, the characteristics of the watershed and watercourse upstream and downstream of the structure, the stability of the channel and the potential accumulation of debris. The developed methodology was implemented to determine the risk in the following case studies, which are located in Spanish territory: (i) in the urban areas corresponding to the towns of Alfafar and Massanassa; (ii) in the stream crossings located in the municipality of Godelleta; and (iii) in 12 river bridges located. The results obtained could be indicating that the proposed method takes into account the most important elements to be considered when establishing this type of risk. The developed methodology provides a detailed vision of the vehicle instability risk due to flooding in a given area. Consequently, implementing this methodology can help to reduce negative effects before and during flooding events, which is extremely helpful for those organizations in charge of urban planning and civil protection to design and take actions that cushion the negative effects of flooding.<br>I thank Colciencias for financing this research through call 728-2015.<br>Bocanegra Vinasco, RA. (2020). Evaluation of the risk due to fluvial flooding in vehicles and road infrastructures at basin scale [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/157654<br>TESIS

Because there is a difference in stiffness between a bridge deck and the materials used in the approach embankment, traffic loading will cause the pavement to deform relative to the bridge deck and form a ‘bump’ at the end of the bridge. This causes drivers’ discomfort and accelerated damage to the pavement. The use of concrete approach slabs constructed so as to slope down from the bridge deck beneath the pavement has been proposed as a means of alleviating this problem. In this thesis, experimental and theoretical work have been carried out to investigate the behaviour of approach slabs under repeated loading. The work is broadly divided into six sections : 1. The development of a testing facility for the testing of model approach slabs under controlled conditions. 2. The assessment of the capability and performance of the testing facility. 3. The planning and conduct of the laboratory testing for the investigation of the deformation behaviour of pavements subjected to traffic loading. 4. The formulation of a three-dimensional finite element program using Fourier transforms for the analysis of the problem. 5. The planning and conduct of monotonic and cyclic drained triaxial tests for the investigation of residual strain behaviour. 6. The analysis of the residual strains in the model embankments and the development of a numerical method for the prediction of permanent displacements. A testing facility has been developed to provide simulated traffic loading on model pavements underlain by approach slabs. Three series of tests have been carried out to investigate the effect of the orientation of the approach slab on the deformation behaviour of the pavements. It is found that with the use of inclined slabs, the deformation in the pavement surface is more gradual than for the case where a horizontal slab is used. In other words, the bump usually formed at the end of a horizontal slab can be eliminated. A finite layer method is developed in this thesis, which provides an efficient means for investigating by the moving wheel. the cyclic stresses generated in the road embankment The effect of the approach slab orientation and the pavement stiffness on the soil response can be examined. Cyclic triaxial tests have been conducted using a fully automated GDS triaxial testing system. The aim of these tests was to investigate the soil residual strain behaviour. The cyclic stress paths have been estimated from the finite layer analyses. The triaxial test results showed that the residual axial strain after the first loading cycle increased linearly with the logarithm of the number of cycles (for the 50 loading cycles carried out for each test). This relationship was to be dependent on the stress level and the gradient of the stress path. The residual strains in the model pavements have been backfigured from two of the tests. The residual strains after the first loading cycle were found to vary non—linearly with the logarithm of the number of loading cycles. However, the non—linearity was less pronounced for the initial 50 cycles or so. A stress path method was developed to utilise the cyclic test data for the prediction of residual axial strains in the pavement layers. Based on this method, the residual strains in the pavement layers after the first loading cycle can be computed. The residual deformations are then obtained by integrating the strains obtained for all the layers. This method was applied to one of the model pavement tests and the results are found to agree reasonably well with the observed values. There are a number of improvements that can be made to this method of prediction, for instance, the incorporation of a non-linear stress-strain law to predict the first cycle deformation. Also, the measurement of the actual stresses acting in the model pavements would be useful in determining the appropriate stress paths for subsequent cyclic tests.

The aim of this diploma thesis is to elaborate a variant of the technical solution of the Northeast bypass road of the city Hranice and its subsequent comparison with other variant prepared by the company Linio Plan, s.r.o. The main task of the bypass road is the operation of the industrial zone, through which is achieved the relocation of a large part of the transit traffic from the city centre. The basic difference of compared variants is their location to the city, the solution developed by Linio Plan, s.r.o. passes through the industrial zone and the other variant passes outside this zone.

The Hampton Roads Bridge-Tunnel is one of the oldest prestressed concrete structures in the United States. The 3.5 mile long twin structure includes the world's first underwater tunnel between two man-made islands. Throughout its 60 years in service, the harsh environment along the Virginia coast has taken its toll on the main load carrying girders. Concrete spalling has exposed prestressing strands within the girders allowing corrosion to spread. Some of the more damaged girders have prestressing strands that have completely severed due to the extensive corrosion. The deterioration has caused select girders to fail the necessary load ratings. The structure acts as an evacuation route for the coast and is a main link for the local Norfolk Naval Base and surrounding industry. Because of these constraints, load posting is not a viable option. Live load testing of five spans was performed to investigate the behavior of the damaged spans. Innovative techniques were used during the load test including a wireless system to measure strains. Two different deflection systems were implemented on the spans, which were located about one mile offshore. The deflection data was later compared head to head. From the load test results, live load distribution factors were developed for both damaged and undamaged girders. The data was also used by the local Department of Transportation to validate computer models in an effort to help pass the load rating. Overall, this research was at the forefront of the residual strength of prestressed concrete girders and the testing of in-service bridges.<br>Master of Science

The content of the thesis is a proposal of steel load-bearing structure (carrying structure of a steel) bridge of the span of 31+74+31m with the bottom bridge deck taking over the second-class road in the territory of Olomouc city. The bridge deck is created by composite steel-concrete slab with crossbars. The solution was focused on using arched construction in the middle of the bridge with different tilt of arches to the horizontal central axis of the bridge. Under the term of the solution four alternatives have been calculated. The most optimal solution was selected and processed in detail. The calculations were made in compliance with the Czech technical norms ČSN EN.

This master's thesis explores the intersections of labor, socioeconomic class, and constructed American Indian masculinities in the literature of indigenous writers of the Great Plains published after the Native American Renaissance of the late 1960s. By engaging scholars and theorists from multiple disciplines--including Native labor historians such as Colleen O'Neill and Alexandra Harmon, (trans)indigenous studies scholars such as Chadwick Allen and Philip Deloria, and Native literary and cultural critics such as Gerald Vizenor and Louis Owens--this thesis offers an American Studies approach to definitions and expressions of work, wealth, and masculinity in American Indian literature of the Great Plains. With chapters on D'Arcy McNickle's posthumous Wind From an Enemy Sky (1978), Carter Revard's poetry and mixed-genre memoirs, and Thomas King's Truth and Bright Water (1999), this thesis emphasizes the roles of cross-cultural apprenticeships for young Native protagonists whose socioeconomic opportunities are often obstructed, threatened, or complicated by dams, roads, and bridges, both literal and metaphorical, as they seek ways to engage (or circumvent) the capitalist marketplace on their own terms. In highlighting each protagonist's relationship to blood (family and community), land, and memory, the chapters reveal how the respective Native authors challenge and reimagine stereotypes regarding Native workers and offer more complicated and nuanced discussions of Native "traditions" in modernity. (173 pages)

Since 1 January 2010 it is a requirement to use the European standards, Eurocodes, in Sweden when constructing bridges. One chapter that has caused an extra amount of problems for the engineers is the one about fatigue analysis, which resulted in us doing this thesis. To do this we had to read all of the Eurocodes that direct, or indirect deals with fatigue and calculating of such. We have read the background documents for the Eurocodes and master’s thesis in the subject. We also studied the calculations of bridges constructed by different construction firms. We have chosen to limit the thesis to discuss only road bridges made of concrete due to the lack of method for verification of concrete in the national appendix. There is a need for clarification of what method to use. To make sure that this thesis will be of use to the constructors, we have presented easy-to-use instructions for how to calculate fatigue on reinforced concrete bridges. We have also calculated an example of a bridge in two spans where we present the calculations in Excel more thoroughly. Fatigue of concrete is in many cases not the critical factor and it can most often be verified by simple methods. The concrete reinforcement is more often the subject to fatigue, but verification can relatively easy be done with the method described in the national appendix if a good Excel- or MathCAD sheet is used.<br>Sedan den 1 januari 2010 är det krav i Sverige att för bro- och anläggningskonstruktioner använda de nya europeiska standarderna, eurokoder, för dimensionering. Ett kapitel som vållat stora problem för brokonstruktörer är kapitlet om utmattningslaster och dimensionering för dessa vilket ledde till att vi gjorde detta examensarbete. Vi har läst igenom de eurokoder som direkt och indirekt behandlar utmattning och utmattningsberäkningar, granskat bakgrundsdokument till eurokoderna samt läst examensarbeten som handlar om utmattning. Dessutom har vi också granskat beräkningar från ett flertal broar som olika konsultföretag konstruerat. Vi har valt att avgränsa arbetet till att enbart handla om utmattning av vägbroar i armerad betong. Detta har vi gjort för att metoder för verifiering av betongen i vägbroar inte är definierade i de nationella tilläggen till eurokoderna. Därför behövs ett förtydligande av vilka metoder som är lämpliga att använda. För att konstruktörer ska ha praktisk nytta av detta examensarbete, har vi redovisat en beräkningsgång med kommentarer och dessutom utfört egna beräkningar för en förenklad variant av en plattbro i två spann där vi redovisar beräkningarna i Excel mer ingående. Vad vi har kommit fram till är att armeringen ofta är mer utsatt för utmattning än betongen men verifieringsmetoden beskriven för armeringen i det nationella tillägget är en metod som är relativt lätt att använda med ett bra Excel eller MathCAD-ark.

An experimental laboratory investigation was carried out to assess the structural adequacy of a disused PHO Class Flat Bottom Rail Wagon (FRW) for a single lane low volume road bridge application as per the design provisions of the Australian Bridge Design Standard AS 5100(2004). The investigation also encompassed a review into the risk associated with the pre-existing damage in wagons incurred during their service life on rail. The main objective of the laboratory testing of the FRW was to physically measure its performance under the same applied traffic loading it would be required to resist as a road bridge deck. In order to achieve this a full width (5.2m) single lane, single span (approximately 10m), simply supported bridge would be required to be constructed and tested in a structural laboratory. However, the available clear spacing between the columns of the loading portal frame encountered within the laboratory was insufficient to accommodate the 5.2m wide bridge deck excluding clearance normally considered necessary in structural testing. Therefore, only half of the full scale bridge deck (single FRW of width 2.6m) was able to be accommodated and tested; with the continuity of the bridge deck in the lateral direction applied as boundary constraints along the full length of the FRW at six selected locations. This represents a novel approach not yet reported in the literature for bridge deck testing to the best of the knowledge of the author. The test was carried out under two loadings provided in AS 5100 (2004) – one stationary W80 wheel load and the second a moving axle load M1600. As the bridge investigated in the study is a single lane single span low volume road bridge, the risk of pre-existing damage and the expected high cycle fatigue failure potential was assessed as being minimal and hence the bridge deck was not tested structurally for fatigue/ fracture. The high axle load requirements have instead been focussed upon the investigation into the serviceability and ultimate limit state requirements. The testing regime adopted however involved extensive recording of strains and deflections at several critical locations of the FRW. Three locations of W80 point load and two locations of the M1600 Axle load were considered for the serviceability testing; the FRW was also tested under the ultimate load dictated by the M1600. The outcomes of the experimental investigation have demonstrated that the FRW is structurally adequate to resist the prescribed traffic loadings outlaid in AS 5100 (2004). As the loading was directly applied on to the FRW, the laboratory testing is assessed as being significantly conservative. The FRW bridge deck in the field would only resist the load transferred by the running platform, where, depending on the design, composite action might exist – thereby the share of the loading which needs to be resisted by the FRW would be smaller than the system tested in the lab. On this basis, a demonstration bridge is under construction at the time of writing this thesis and future research will involve field testing in order to assess its performance.

The subject of my diploma thesis is to design the intersection of roads I/44 and II/453 in urban area of Jeseník. Part of the proposal is to address traffic and pedestrian connection to the adjacent tertiary roads.

<p>This thesis discusses the archaeological remains in the Etruscan bridge complex, found during the excavations at San Giovenale in 1959–1963, and 1999. The aim has been to reach a holistic perspective of the bridge complex with the bridge seen as a link between topography, economy, social relationships, politics, symbols and ritual, reflecting its importance for the whole community at San Giovenale and its surroundings. Situated at the border between the two largest city-states Tarquinia and Caere, the site seems to have been an important middle range transit town for foreign ideas, goods and people. </p><p>The character of the remains and the various levels of contextual analyses made it possible to distinguish five distinctive functions for the structures at the bridge over the Pietrisco. From a more generalised point of view these suggested that specialized functions may be divided into practical, social and symbolic functions and these aspects have been of help in identifying an object or a structure. Besides practical functions of everyday use, economic and strategic functions have also been considered. </p><p>These functions were more or less in use contemporaneously, at least during several hundred years, from about the middle of the 6th down to the first century B.C. Pottery and small finds show that some activity has taken place at the site from the 9th century. Features of continuity, such as in the choice of crossing, the direction of the bridge construction after its destruction, the architectural ground-plans, the use of basins and a well, pottery fabrics of local and Greek imports and shapes, as well as changes in ground-plans, slight changes in the environment due to water erosion, earth-quakes and slides, have been observed. The physical as well as the liminal boundary between land and water as well as between man and spirits was accentuated by the tufa building, the water installations, and the road at the northern abutment. The thesis raises the hypothesis that the Etruscans believed that a crossing of a river via a bridge could violate the spirits of nature on land and in the water and therefore special rites were needed to restore the balance between nature and man before entering the bridge in order to reach safely at the other side of the ravine. The bridge itself can be seen as sacred, a liminal area where time and space do not exist and a place where it is easy to gain contact with the supernatural world. </p>

The subject of Diploma’s thesis is the design of a road bridge on the R1 expressway, at km 1,293 above the road III/51311. The main content is static calculation of supporting structure consisting of four spans. Four studies were processed and the first variant of double-girder monolithic structure was chosen. The range of spans is ranging from 25 m - 30 m. Double-girder consists of two post-tensioned concrete beams and reinforced concrete slab. Static models and load effects are solved in Scia Engineer. Bridge is located in the horizontal curvature, however, compromise was elected (because of small curvature), assessing the upright design. Calculation is made without effects of temperature, wind loads and horizontal forces causing by traffic.

The aim of the master thesis was a design of the steel-concrete composite road bridge for a main road in Ostrava. The part of the design was a variant design of the bridge which has theoretical spans equal to 44 m + 55 m + 44 m. Total span of the bridge is then 143 m. Two variants of the bearing steel structure are compared in the preliminary structural design, in the first one a twin-girder is designed and in the second one a box-girder bridge is assessed. The width of the bridge is 14 m and a launching of the bridge without temporary supports is chosen as the assembly method. The design of the bridge structure was carried out according to the valid standard ČSN EN. The final thesis contains variant design, structural design report, where a bill of quantities is stated, engineering report and drawings.

Based on Dunning's dominant international business theory and the unique characteristics of construction, a novel framework is developed and tested to explain multinational contracting into Australia. Beyond contributions to theory, Australian governments now have clear evidence upon which to develop more effective procurement reform towards increasing the attractiveness of public sector major infrastructure projects and competition in this sector.

My master's thesis aims to design a bridge construction spanning road III/443 over road I/44. Three versions were created one of which has been developed further. It is a three span bridge with a total spread of 77.5 meters. Proposal and evaluation of bridge construction is done unassisted. Static analysis is done using Scia Engineer program. Construcion evaluation is done by valid EU norms ČSN EN 1992-1-1. Mechanical drawing, building procedure and visualisation is also included.