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Ek, Therese. "Fatigue analysis of engine brackets subjected to road induced loads." Thesis, KTH, Hållfasthetslära (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193564.
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In this master thesis, methods for fatigue analysis of front engine brackets subjected to road induced gravity loads (g-loads) are studied. The objective of the thesis is to investigate the possibility to improve simulation and test analysis for the components. The powertrain is modeled with varying degrees of complexity and the different models are compared to each other and to Scania's models for analysis of the engine suspension. The analysis begins with g-loads and proceeds with time-dependent loads. It is investigated how simulated strains in the cylinder block correspond to measured strains from the test track at Scania. Finally, it is investigated how component tests corresponds to actual loads by comparing the results. The results from the first part of the thesis indicate that worst load case is loading in the negative z -direction and the model of the powertrain with isolators modelled as spring elements is the best for g-loads lower than -3g and the model is sufficient for loads lower than -8g. The results from the second part of the thesis indicate that the simulated strains generally correspond to the measured strains, but with a slight difference in strain amplitude.
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Rhee, Hakjun. "Inferring traffic induced sediment production processes from forest road particle size distributions /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/5459.
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Wang, Juan. "Shakedown analysis and design of flexible road pavements under moving surface loads." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12836/.
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Flexible road pavements often fail due to excessive rutting. as a result of cumulative vertical permanent deformation under repeated traffic loads. The currently used analytical approach to flexible pavement design evaluates the pavement life in terms of critical elastic strain at the top of the subgrade. Hence, the plastic pavement behaviour is not properly considered. Shakedown analysis can take into account the material plasticity and guarantee structure stability under repeated loads. It provides a more rational design criterion for flexible road pavements. Finite element analyses using the Tresca and Mohr-Coulomb yield criteria are performed to examine the responses of soil half-space when subjected to different loading levels. Both shakedown and surface ratchetting phenomena are observed and the residual stresses are found to be fully-developed after a limited number of load passes. The finite element results are then used to validate the solutions from shakedown analysis. The main focus of current research is concerned with new solutions for static (i.e. lower-bound) shakedown load limits of road pavements under both two-dimensional and three-dimensional moving surface loads. Solutions are derived by limiting the total stresses at any point (i.e. residual stresses plus loading induced elastic stresses) to satisfy the Mohr-Coulomb yield criterion. Previous analytical shakedown solution has been derived based on a residual stress field that may not satisfy equilibrium for certain cases. In this study, a rigorous lower-bound shakedown solution has been derived by imposing the equilibrium condition of residual stresses. The newly developed shakedown solutions have been applied to one-layered and multi-layered pavements. It was found that the rigorous lower-bound solution based on the self-equilibrated residual stress field is lower than the analytical shakedown solution for cases when the critical point lies on the surface or at the base of the first pavement layer. The results showed that the theoretical predictions of pavement shakedown load limit generally agree with the finite element and experimental observations for pavement behaviours. The shakedown solution has been further extended to study the influence of the shape of contact load area for pavements under three-dimensional Hertz loads. It was found that the shakedown load limit can be increased by changing the load contact shape from a circle area to an elliptical one. A new pavement design approach against excessive rutting has been proposed. The pavement design is suggested by plotting thickness design charts using the direct shakedown solutions and choosing the thickness combination based on the design traffic load.
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Zia, Seiar Ahmad. "The effect of different road load implementation strategies on fuel economy of USPS step vans." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10375.
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Thesis (M.S.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains xii, 92 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 79-81).
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Fauriat, William. "Stochastic modeling of road-induced loads for reliability assessment of chassis and vehicle components through simulation." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22689/document.
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Concevoir un composant automobile et s’assurer que celui-ci atteindra un niveau de fiabilité cible requière une connaissance précise de la variabilité des chargements que ce composant est susceptible de rencontrer dans son environnement d’utilisation. La grande diversité des chargements appliqués à différents véhicules par différents clients, ou à un même véhicule tout au long de son historique d’utilisation, représente un défi statistique majeur. Généralement, l’acquisition d’information relative à la variabilité des chargements imposés aux composants des véhicules, repose sur la réalisation de campagnes de mesures. La complexité, la durée et le coût de telles campagnes limite naturellement la taille des échantillons statistiques constitués et les chargements enregistrés sont inévitablement dépendants du véhicule utilisé pour la mesure.Le travail présenté dans ce manuscrit explore la possibilité de changer fondamentalement d’approche, en se basant sur la simulation plutôt que sur la mesure et en concentrant l’effort d’analyse statistique non pas directement sur la variabilité des chargements mais sur la variabilité des facteurs qui les déterminent. Dans ce but, des modèles stochastiques sont proposés pour décrire l’évolution de la géométrie des surfaces de routes rencontrées par les véhicules ainsi que l’évolution de la vitesse à laquelle les conducteurs les parcourent. La caractérisation de la variabilité de ces facteurs est couplée à la notion de situations de vie. Ces dernières permettent de segmenter l’historique d’utilisation des véhicules, afin de faciliter l’analyse statistique de leur évolution au sein d’une population de clients. Pour finir, la réponse dynamique du véhicule à l’excitation générée par la route est déduite par la simulation.Des données statistiques relatives à la variabilité des facteurs de route et de vitesse sont évidemment nécessaires. L’information sur les routes parcourues peut par exemple être acquise à moindre coût au moyen d’une méthode d’estimation des profils de route proposée dans ce manuscrit. Cette information peut ensuite être exploitée afin de constituer, par la simulation, à un coût très faible et pour n’importe quel véhicule dont les caractéristiques sont connues, un échantillon d’historiques de chargements aussi important que souhaité. Cette méthodologie basée sur la simulation offre la possibilité d’analyser plus largement la variabilité des chargements de fatigue provenant de la route, l’influence des différents facteurs qui les déterminent ainsi que l’effet sur la fiabilité des composants du véhicule étudiéIn order to design vehicle components that will achieve a prescribed reliability target, it is imperative to possess a precise description of the variability of the loads to which such components may be subjected within the environment in which they are used. The strong diversity of the loads imposed on different vehicles by different customers, or on a particular vehicle throughout its life, constitutes a formidable statistical challenge. Generally, the acquisition of information about the load variability experienced by vehicle components is based on the use of load measurement campaigns. The complexity, duration and cost of such campaigns naturally limit the size of the statistical samples that may be collected. Moreover, the recorded load histories are inevitably dependent on the vehicle used for the measurements.The work presented within this manuscript explores the possibility of a fundamental change in the approach to load characterisation. The objective is to make use of simulation rather than measurements and focus statistical analysis efforts not directly on load variability itself but on the variability of the factors that determine such loads. Stochastic models are proposed to describe the evolution of the geometry of road surfaces covered by vehicles, as well as the evolution of vehicles’ speed on those road surfaces. The characterisation of the variability of such factors is performed in combination with the use of life situations. The latter may be employed to divide the load histories associated to different vehicles, within a population of customers, and analyse their variation more easily. Eventually, the dynamic response of the vehicle to the excitation imposed by the road can bederived through simulation.Statistical data on the variation of the road and speed factors obviously have to be acquired in order to apply the methodology. For example, road-related information may be obtained through the use of a road profile estimation algorithm proposed within the framework of this manuscript. Such information may then be exploited to constitute, through simulation, an arbitrarily large set of load histories at a very low cost and for any vehicle whose mechanical characteristics are known.The proposed methodology based on simulation enables us to study more extensively the variability of road-induced fatigue loads, the influence of the different factors that determine such loads, as well as the effect they have on the reliability of any considered vehicle component
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Khavassefat, Parisa. "Vehicle-Pavement Interaction." Doctoral thesis, KTH, Väg- och banteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156045.
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Several aspects of vehicle-pavement interaction have been studied and discussed in this thesis. Initially the pavement response is studied through a quasi-static and a dynamic computationally efficient framework under moving traffic loads. Subsequently, a non-stationary stochastic solution has been developed in order to account for the effect of pavement surface deterioration on pavement service life.The quasi-static procedure is based on a superposition principle and is computationally favourable, as it requires only a reduced incremental problem to be solved numerically. Using the developed framework, the effect of vehicle configuration and traffic characteristics on the damage induced in pavements is investigated numerically. It is shown that the developed numerical model provides a more accurate explanation of different distress modes.In the dynamic approach the pavement roughness and vehicle suspension system are linked to a dynamic pavement model in order to account for the dynamic effects of vehicle-pavement interaction on pavement response. A finite element method is employed in order to establish the response function for a linear viscoelastic pavement structure with dynamic effects taken into account. The developed computational procedure is applied to evaluate the effect of the pavement surface roughness on the pavement structure response to truck traffic loadings.Furthermore, the deterioration trends for the flexible pavement surface have been investigated based on field measurements of longitudinal profiles in Sweden. A predictive function is proposed for surface deterioration that is based on the average gradient of yearly measurements of the road surface profiles in Swedish road network. The developed dynamic framework is further elaborated to a non-stationary stochastic approach. The response of the flexible pavement is given for a non-stationary random case as the pavement surface deteriorates in pavement service life, thus influencing the magnitude of the dynamic loads induced by the vehicles. The effect of pavement surface evolution on the stress state induced in the pavement by moving traffic is examined numerically. Finally the effect of surface deterioration on pavement service life has been investigated and discussed in the thesis by incorporating the proposed prognostic surface deterioration model into a ME design framework. The results are discussed for different case studies with different traffic regimes. It was indicated that the predicted pavement service life decreases considerably when the extra dynamic loads, as a result of pavement surface deterioration, has been taken into account. Furthermore, the effect of performing a predictive rehabilitation process (i.e. resurfacing) has been studied by employing a LCC framework. The application of preventive maintenance was shown to be effective, especially when the deterioration rate is high.QC 20141119
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Horký, Martin. "Měření aerodynamických charakteristik vozidla na základě jízdních testů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231526.
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Kuře, Arnošt. "Vyhodnocení legislativních předpisů pro speciální silniční přepravu mezi Českou republikou a severní Evropou." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-232486.
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he project evaluates legislative regulations for special road transport between the Czech Republic and Northern Europe. The main purpose of the project is to formulate a basic methodology for non-standard shipment’s transit. Work observes destination of the Czech Republic - Denmark, Finland, Norway and Sweden. There exist differences in legislative conditions for the particularly heavy and oversized loads transport in these countries. The main objective is to evaluate these conditions and recommend utilization for Czech carriers. The thesis aims to enumerate the various national legal standards for excessive transportation and recommend implementation outputs for correct and a quick orientation in the rights and obligations during executing carriage for the Czech carriers. The basic metodology how to transport oversized loads results from this project.
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Igbe, Damian. "Dynamic load balancing of parallel road traffic simulation." Thesis, University of Westminster, 2010. https://westminsterresearch.westminster.ac.uk/item/90644/dynamic-load-balancing-of-parallel-road-traffic-simulation.
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The objective of this research was to investigate, develop and evaluate dynamic load-balancing strategies for parallel execution of microscopic road traffic simulations. Urban road traffic simulation presents irregular, and dynamically varying distributed computational load for a parallel processor system. The dynamic nature of road traffic simulation systems lead to uneven load distribution during simulation, even for a system that starts off with even load distributions. Load balancing is a potential way of achieving improved performance by reallocating work from highly loaded processors to lightly loaded processors leading to a reduction in the overall computational time. In dynamic load balancing, workloads are adjusted continually or periodically throughout the computation. In this thesis load balancing strategies were evaluated and some load balancing policies developed. A load index and a profitability determination algorithms were developed. These were used to enhance two load balancing algorithms. One of the algorithms exhibits local communications and distributed load evaluation between the neighbour partitions (diffusion algorithm) and the other algorithm exhibits both local and global communications while the decision making is centralized (MaS algorithm). The enhanced algorithms were implemented and synthesized with a research parallel traffic simulation. The performance of the research parallel traffic simulator, optimized with the two modified dynamic load balancing strategies were studied.
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Åberg, Skender Dennis. "Modelling of Test Bench for Road Load Simulation." Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-141957.
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Warehouse forklifts are often powered by batteries. By using a test bench where the forklift can be driven in a certain driving-cycle, the battery capacity can be tested. To obtain the same speed curve on the test bench as a forklift obtains when driving on a real road, the test bench must be able to simulate road load. In this master’s thesis, a test bench is modelled in Simulink using grey-box modelling and validated with measured data. Also, a speed regulator is developed and implemented in the test bench model to simulate road load. Simulations with the model and the speed regulator show high accuracy when compared against measured data. However, the results show that the pre-attached torque sensor is not optimally located, and that the gear oil temperature is of interest to measure to be able to model the friction torque as a function of the temperature.Lagertruckar drivs ofta av batterier. Batterikapaciteten kan testas genom att använda en testbänk där trucken körs i en körcykel. För att simulera samma hastighetskurva på testbänken som trucken erhåller vid riktig körning på väg måste testbänken kunna simulera vägmotstånd. I detta examensarbete modelleras en testbänk i Simulink genom grey-box modellering och valideras med uppmätt data. Även en hastighetsregulator utvecklas och implementeras i modellen för att simulera vägmotstånd. Simuleringar med modellen och hastighetsregulatorn visar på hög träffsäkerhet jämfört med uppmätt data. Resultaten visar dock på att den monterade momentsensorn inte är optimalt belägen och att växeloljans temperatur är av intresse att mäta för att kunna modellera friktionen som en funktion av temperaturen.
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Moynahan, Nathan A. "Development of a vehicle road load model for ECU broadcast power verification in on-road emissions testing." Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4454.
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Thesis (M.S.)--West Virginia University, 2005.Title from document title page. Document formatted into pages; contains xi, 117 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 75-77).
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Singh, Yuvraj. "Regression Models to Predict Coastdown Road Load for Various Vehicle Types." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595265184541326.
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Davis, A. G. W. "A transputer ring network for real time distributed control applications." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260571.
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Lui, Sai-yan, and 雷世昕. "Road for reverse mortgage programme in Hong Kong : a study of consumer's perception." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207665.
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Reverse Mortgage Programme (“RMP”) was launched in Hong Kong on 11th July 2011. It aims to help the elderly to improve the living standard. Since the aging population is getting serious and the lack of comprehensive retirement protection scheme in Hong Kong, a big potential market for reverse mortgage is given which is anticipated that the eligible elderly should eagerly participate to the programme.
However, the statistic from the Hong Kong Mortgage Corporation (“HKMC”) showing that the participation rate of RMP is surprisingly low. Up to 31st May 2014, only 624numbers of applications were recorded. In order to boost the participation rate, this dissertation has conducted a study to identify the reason(s) of low participation rate and explore the possible way(s)to enhance the RMP.
In order to achieve the aim of the study, a questionnaire survey was conducted to investigate the consumer’s perception to RMP. It divided consumer’s perception into consumer’s awareness and consumer’s motivation. High awareness but low understanding to RMP was found according to the results of survey. Meanwhile, low consumer’s motivation to RMP was found and the complicated programme content and legacy concern are the major factors influencing the consumer’s motivation.
Nevertheless, there still a long way to go for the RMP in Hong Kong. To enhance the performance of RMP, it is recommended to promote it by different means of media and focus it to the elderly without children. Further studies would be needed to assess the effectiveness of the approaches in the recommendation.published_or_final_version
Housing Management
Master
Master of Housing Management
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Reilly, James Joseph. "Load Testing Deteriorated Spans of the Hampton Roads Bridge-Tunnel for Load Rating Recommendations." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/74302.
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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.Master of Science
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Bailey, Simon F. Bailey Simon Frederick. "Basic principles and load models for the structural safety evaluation of existing road bridges /." Lausanne : EPFL, 1996. http://library.epfl.ch/theses/?nr=1467.
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Lindgren, Magnus. "Engine exhaust gas emissions from non-road mobile machinery : effects of transient load conditions /." Uppsala : Dept. of Biometry and Engineering, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a481.pdf.
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Vogeler, Isabell [Verfasser], Thomas [Akademischer Betreuer] Schütz, Cameron [Akademischer Betreuer] Tropea, and Hermann [Akademischer Betreuer] Winner. "Road Load Determination in a Wind Tunnel / Isabell Vogeler ; Thomas Schütz, Cameron Tropea, Hermann Winner." Darmstadt : Universitäts- und Landesbibliothek, 2021. http://d-nb.info/1240834160/34.
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Teixeira, Lucas Augusto Costa. "Caracterização de payloads via telemetria." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/157749.
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O preço atual do minério de ferro obrigou as empresas a reduzirem os custos operacionais na fase mina. O carregamento e transporte de materiais com utilização de escavadeiras e caminhões grande porte representam grande parcela do custo total, particularmente com pneus, diesel, manutenção e mão de obra. Metas de movimentação anual são divididas durante os meses e as condições climáticas podem influenciar na produtividade e desempenho dos equipamentos. O banco de dados da movimentação mensal está condicionado com a capacidade de cada caminhão. Cada frota possui o payload característico e este representa a capacidade de transporte, sendo o valor da massa transportada o único parâmetro extraído em cada ciclo, sem considerar o posicionamento do material sobre a caçamba dos equipamentos. Forças de cisalhamento e torção são aplicadas constantemente no chassi e pneus dos caminhões e, quando as cargas estão descentralizadas, potencializam estes eventos. O transporte de cargas descentralizadas agride os pneus diminuindo a vida útil causando danos como deslocamento da banda de rodagem e separação do flanco. Este trabalho teve como objetivo diminuir as ocorrências de cargas descentralizadas e os custos operacionais. Para incrementar o posicionamento do material sobre as caçambas, a telemetria foi a ferramenta utilizada. Análises de pressões de suspensões indicam o posicionamento das cargas e através desses valores foi criado um banco de dados. Este banco de dados pode indicar qual operador de carga precisa de reciclagem, contribuindo para a redução de cargas descentralizadas e custos, uma vez que cargas deste perfil sucateiam precocemente pneus e suspensões. O estudo foi realizado em Itabira, em uma mina de minério de ferro a céu aberto. A metodologia comprovou ser capaz diminuir as ocorrências de cargas descentralizadas assim como aumentar a vida útil de pneus. Uma possível economia foi apresentada para ano de 2014, período em que a média das horas trabalhadas de pneus ficou abaixo da meta aumentando os custos fase mina.The actual iron ore price forces the companies to reduce costs in all production steps of the mining operation. Loading and hauling materials using shovel-truck system represents the highest mining costs, particularly tires, diesel, maintenance and workforce. Annual goals of materials movement are split by months were weather conditions can affect productivity and performance of the fleet. The data file of the monthly material movement is based on the scale of each truck. Every fleet has a payload and it represents the capacity of hauling, being the value of loading a unique input extracted in each duty cycle, without taking into account the position of the material over the truck’s dump. Shear forces and torsion are applied all time at the frames trucks and, when the truckloads are unbalanced, increases the forces over the frame and tires. Transport unbalanced truckloads into long distances attack the tires and decrease its end of life, causing damages like displacement of tread and flank separation. The objective of this study is to propose a methodology to decrease unbalanced truck loads reducing the mining costs. In this mission of incorporating a material position on the truck´s dump, the telemetry was taking into consideration. The analysis of the suspension pressures data values shows the truckloads positions and with this data was created a databank. This databank indicates that the operators need truck load training to reduce unbalanced loads and truck costs in the mining operation, since unbalanced loads leads to early tires and suspensions scrap. The case study was carried out at Itabira Iron Ore Mine Complex, Brazil. This methodology was able to reduce the number of unbalanced truck loads as well as the tires life was increased. An economic saving estimate is presented based on 2014 scrapped tires data bank, in this year the tires life cycle was underneath, burdening operational costs.
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Bawaqneh, Hamdi. "Virtual Vehicle Pitch Sensor." Thesis, Linköpings universitet, Institutionen för systemteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69944.
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An indirect tire pressure monitoring system uses the wheel rolling radius as an indicator of low tire pressure. When extra load is put in the trunk of a car, the load distribution in the car will change. This will affect the rolling radius which in its turn will be confused with a change in the tire pressure. To avoid this phenomenon, the load distribution has to be estimated. In this thesis methods for estimating the pitch angle of a car and an offset in the pitch angle caused by changed load distribution are presented and when an estimate is derived, a load distribution can be derived. Alot of available signals are used but the most important are the longitudinal accelerometer signal and the acceleration at the wheels derived from the velocity of the car. A few ways to detect or compensate for a non-zero road grade are also presented. Based on the estimated offset, a difference between the front and rear axle heights in the vehicle can be estimated and compensating for the changed load distribution in an indirect tire pressure monitoring system will be possible.
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Lykvist, Peter, and Mathias Blom. "Utmattning av vägbroar i armerad betong enligt eurokoder." Thesis, KTH, Byggteknik och design, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-49147.
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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.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.
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Fontenele, Heliana Barbosa. "Representação do tráfego de veículos rodoviários de carga através de espectros de carga por eixo e seu efeito no desempenho dos pavimentos." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18143/tde-12032012-111950/.
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A caracterização das cargas do tráfego é de grande importância para o dimensionamento de pavimentos, bem como para a quantificação do desempenho para fins de gerência de pavimentos. A utilização de abordagens empíricas para determinar os efeitos das cargas do tráfego nas estruturas de pavimentos, datadas dos anos 1960, apresentam sérias limitações, pois seus resultados são válidos somente para os mesmos, ou muito similares, fatores intervenientes que prevaleciam quando do seu desenvolvimento. Os fatores relativos às solicitações do tráfego e às características dos veículos (tipo de eixo, tipo de rodagem, pressão de enchimento dos pneus e tipo de suspensão) são bem diferentes, atualmente, daquelas existentes há 50 anos. Tendo em vista que os modelos de desempenho são importantes ferramentas dos sistemas de gerência de pavimentos (SGP) para prever a evolução da condição ao longo do tempo e/ou tráfego acumulado e, portanto, dependentes de uma consistente caracterização do tráfego, o objetivo desta pesquisa foi analisar os efeitos da caracterização do tráfego sobre o desempenho dos pavimentos, a partir da geração de modelos estatísticos baseados no conceito proposto pelo método da AASHTO 2002, de espectros de carga por eixo dos veículos comerciais de carga, comparando-os com o conceito de equivalência de carga, desenvolvido a partir do AASHO Road Test na década de 1950. Dados de pesagens realizadas no ano de 2008 no Posto de Pesagem de Veículos da SP-160 Rodovia dos Imigrantes, km 28, pista Sul, foram utilizados para o desenvolvimento dos espectros de carga e posterior modelagem. Testes estatísticos e práticos foram realizados para determinar a variabilidade mensal dos Fatores de Veículos (FV) em relação ao valor médio do ano de 2008. Apesar da análise estatística com a aplicação do teste Kolmogorov-Smirnov (K-S) ter apresentado diferenças significativas entre os espectros mensais e anuais, a variação observada nos fatores de tráfego não resultou em diferenças práticas na espessura final do pavimento. Os modelos estatísticos foram desenvolvidos separadamente para cada classe de veículo e de eixos que o compunha, tendo sido usadas distribuições de probabilidade Log-normal e Weibull para modelar os espectros de carga. Os parâmetros dos modelos foram obtidos através do método dos mínimos quadrados, complementado com a realização de testes K-S e Qui-quadrado, destacando-se a obtenção de coeficientes de determinação (R2) superiores a 0,90. A comparação entre os resultados previstos pelos modelos e os dados originais, feita tanto pela abordagem empírica como empírico-mecanística, com uso dos programas computacionais ELSYM5 e MEPDG, evidencia o modelo Weibull como o mais indicado para aplicação em rodovias brasileiras com características de tráfego semelhantes às da Rodovia dos Imigrantes.The characterization of traffic loads is of great importance for pavement design, as well as for the measurement of performance in a pavement management system. The use of empirical approaches to determine the effects of traffic load on pavement structures, dating from the 1960\'s, presents serious limitations, since its results are just valid for the same or very similar intervening factors that prevailed at the time of its development. The traffic load factors and vehicle characteristics (axle type, tire type, tire inflation pressure, and suspension type) are quite different today from those existing 50 years ago. Given that the performance models are important tools of pavement management systems (PMS) to predict the evolution of pavement condition over time and/or accumulated traffic and therefore dependent on a consistent characterization of the traffic, the objective of this research was to analyze the effects of traffic characteristics on pavement performance through the generation of statistical models based on the concept proposed by the AASHTO 2002 method, axle load spectra of commercial vehicles, comparing them with the concept of load equivalence factor, developed through the AASHO Road Test in the 1950s. Data collected in 2008 in a weighing station located on Immigrant Highway - SP-160, km 28, southern runway, were used for the development of load spectra and subsequent modeling. Practical and statistical tests were performed to determine the variability of monthly vehicle-factors (FV) to the mean value for the year 2008. Despite the statistical analysis, performed by applying the Kolmogorov-Smirnov (KS) test, have shown significant differences between the monthly and annual spectra variation, there were not practical differences in the final thickness of the pavement associated to changes in vehicle-factors. Statistical models were developed for each vehicle class and for its axles, having been used Log-normal and Weibull probability distributions to model the load spectra. The model parameters were obtained from the method of least squares, complemented by the KS and chi-square tests, being important to mention that the coefficients of determination (R2) were greater than 0.90. The comparison between the results predicted by the models and the original data, made either by empirical and empiricalmechanistic approaches, with use of computer programs ELSYM5 and MEPDG, shows that the Weibull model is the most suitable for application in Brazilian highways with similar traffic characteristics to the Immigrants Highway.
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Steinert, Bryan Christopher. "Field and Laboratory Evaluation of the Portable Falling Weight Deflectometer." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/SteinertBC2005.pdf.
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Al-Humeidawi, Basim Hassan Shnawa. "Evaluation of the performance of GFRP dowels in Jointed Plain Concrete Pavement (JPCP) for road/airport under the combined effect of dowel misalignment and cyclic wheel load." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/evaluation-of-the-performance-of-gfrp-dowels-in-jointed-plain-concrete-pavement-jpcp-for-roadairport-under-the-combined-effect-of-dowel-misalignment-and-cyclic-wheel-load(3a25c529-04ea-4899-8b7a-64bcfc450809).html.
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Dowel bars are provided at the transverse joints of the Jointed Plain Concrete Pavement (JPCP) to transfer the load between adjoining slabs and to allow for expansion and contraction of the pavement due to temperature and moisture changes. The current study involved evaluation of the performance of Glass Fibre Reinforced Polymer (GFRP) dowels in JPCP as an alternative to the conventional epoxy-coated steel dowel bars, especially in the presence of dowel misalignment. This research involved two main sets of experimental tests. The first set focused on the evaluation of load-deflection response of GFRP dowels using a scaled model of pavement slabs. The second set investigated the combined effect of dowel misalignment and cyclic wheel load on the performance of steel and GFRP dowels. The tested slabs (in the second set) were supported on a steel-beam base with stiffness such that the effects of the underlying layers of real pavements are incorporated. In both of these sets of experiment the GFRP dowels were compared with the steel dowels of similar flexural rigidity. The research also involved detailed numerical investigations using ABAQUS for all experimental tests in the current study. The validated numerical model was used to conduct three sets of parametric studies: to propose design considerations for the GFRP dowels; to simulate all important cases of dowel misalignment (111 cases) for steel and GFRP dowels and to give an insight into the damaged volume in the surrounding concrete pavement; and to investigate the effects of diameter, length and type of dowel bar, concrete grade, pavement thickness, and slab-base friction on the joint-opening behaviour. The results from the first set of experiments showed that the 38 mm GFRP dowels perform better in terms of deflection response compared to the 25 mm steel dowels. Also, it was observed that the relative deflection (RD) is more sensitive to the changes in the joint width rather than the concrete strength. The numerical results from the first set showed a good agreement with the experimental results and showed lower magnitude and better distribution of stress in the concrete underneath the GFRP dowels as compared with the steel dowels. Finally, on the basis of a detailed parametric study (70 different cases), design considerations for GFRP dowels in JPCP were suggested. The second set of experimental results showed that the GFRP dowels can withstand a cyclic traffic load and significantly reduce joint lockup and dowel looseness (DL) and can provide sufficient load transfer efficiency (LTE). It was also observed that the dowel misalignment affects DL significantly more than the repeated traffic load. Slab-base separation and the orientation of misaligned dowels have significant effects on the pull-out load required to open the joint. The numerical results from the second set indicated that the pull-out load was small for the vertical misalignment cases compared to the horizontal and combined misalignment cases. The results also indicated the occurrence of concrete spalling and deterioration at smaller joint openings for combined misalignment when compared to other misalignment types. The use of GFRP dowels significantly reduced the pull-out load and joint lockup when dowel misalignment exists. Consequently, the deterioration of the surrounding pavement substantially decreased. The long term performance of the JPCP fitted with GFRP dowels improves because of a reduction in the DL and the RD, and by maintaining a good LTE even for misaligned dowels. The numerical results also showed that the pull-out load increases significantly for an increase in the concrete compressive strength and the dowel bar diameter. Small increase in pull-out load was observed for higher embedded length of the dowel bar, whereas the increase was insignificant for an increase in the pavement thickness and slab-base friction. In general, the study showed the GFRP dowel can be a potential alternative for the conventional steel dowel bars in JPCP.
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Souza, Leandro Pugliesi de. "Um modelo para análise da compatibilidade de tráfego entre um caminhão ou uma combinação de veículos de carga e um trecho de rodovia." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18144/tde-14102009-161939/.
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Esta pesquisa avalia a aplicabilidade de modelos matemáticos para analisar a compatibilidade de tráfego de caminhões e combinações de veículos de carga com trechos de rodovias. Os modelos avaliados permitiram a elaboração de um simulador de tráfego de veículos rodoviários de carga em trechos de rodovias, permitindo determinar o perfil de velocidades com base nas características mecânicas do veículo e o perfil da rodovia. O método permite ainda obter os valores de aceleração, potência utilizada, e consumo de combustível. Os resultados obtidos mostraram-se consistentes com observações de campo e recomendações de manuais de projeto de rodovias. Outros fatores associados à compatibilidade entre veículos e rodovias, como capacidade de frenagem motora, capacidade de frenagem de emergência, requisitos de sobrelargura, estabilidade veicular, influência do comportamento do condutor sobre as simulações, consumo de combustíveis e emissões de poluentes são discutidos. Conclui-se que o simulador tem utilidade tanto como ferramenta de análise da compatibilidade de tráfego de veículos de carga em trechos de rodovias, como para identificar deficiências de projeto geométrico de rodovias para autorizar o tráfego de determinadas configurações veiculares.This research evaluates the applicability of mathematical models to analyze the traffic compatibility of trucks or cargo combination vehicles with road segments. The evaluated models led to a cargo vehicle locomotion simulator along a road segment, that calculates the speed profile of the vehicle as a function of its mechanical characteristics and the road profile. The method also calculates values of acceleration, used power, and fuel consumption. The results obtained are consistent with field observations and recommendations of road design manuals. Others factors associated with the traffic compatibility of cargo vehicles with geometric characteristics of a road segment like engine braking capability, emergency braking capability, overwidht requirements, vehicle stability, conductor influence, fuel consumption, and emissions rates are also discussed. The conclusion is that the simulator can be used as a tool for traffic compatibility analysis of cargo vehicles with road sections or to identify road design deficiencies to certify traffic of certain vehicle configurations.
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Gaspareto, Douglas dos Santos. "Análise de sistema automatizado de pesagem veicular com plataformas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/169334.
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Este trabalho apresenta um estudo sobre o comportamento de sistemas de pesagem em movimento baseados em plataformas comumente utilizadas no Brasil. Parâmetros relevantes nesse comportamento são modelados: rugosidade aleatória da pista, dinâmica vertical do veículo e sua velocidade, desnível entre a pista e plataforma e dinâmica da plataforma. Duas classes de veículos são simuladas trafegando a diferentes velocidades e sendo pesados utilizando uma proposta de modelo de plataforma rígida e uma proposta de plataforma flexível. As forças de reação do solo e históricos de aceleração em vários GDL são registrados a fim de obter a carga estática por eixo e os erros nas estimativas do peso para o modelo de plataforma rígida. Já para o modelo de plataforma flexível, as forças de reação servem de entrada no modelo de elemento finitos de viga Euler-Bernoulli com consideração da área de contato do pneu através de um trem de cargas. Conclusões relacionadas à redução da precisão do sistema com o aumento da velocidade do veículo são confirmadas, embora importantes conclusões não tão óbvias sobre a importância da dinâmica do veículo, do nível de rugosidade da pista, da altura do degrau pista-plataforma e da dinâmica da plataforma de pesagem são ressaltadas.This work proposes a numerical study on the behavior of weigh-in-motion systems based on load platforms useful in Brazil. Some important parameters that may control this behavior that are modeled are random road roughness, vehicle vertical dynamics, vehicle speed, load platform step’s height to the road and platform dynamics. Two vehicles types are modelled travelling at different speeds and being weighted using a rigid platform proposal and another proposal with a flexible platform. Ground reaction force and acceleration time history on several degree-of-freedom are recorded in order to obtain the static load per axis and the corresponding estimated errors for the rigid platform model. For the flexible platform model, the reaction forces serve as inputs into the Euler-Bernoulli finite element model with consideration of the contact area of the tire by train of loads. Some usual conclusions related to the reduction in the accuracy of the measuring system with increased vehicle speed are confirmed in the numerical study, although important conclusions not so obvious concerning the importance of road roughness, vehicle vertical dynamics, and vehicle speed, load platform step’s height to the road and platform dynamics are highlighted.
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Katz, Leonardo Behak. "Análise estrutural de pavimentos de baixo volume de tráfego revestidos com solo modificado com cal considerando ensaios laboratoriais e monitoramento de trechos experimentais." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/86442.
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Os solos das regiões arrozeiras apresentam características geotécnicas inadequadas para uso como revestimentos primários de estradas. Isto força o transporte de materiais de jazidas distantes, o que, além de onerar o custo de construção, nem sempre é uma solução durável. Nesta tese relata-se uma pesquisa que apresenta uma solução para esse problema: a pavimentação de estradas de baixo volume de tráfego com solo local modificado com cal. Foram realizados estudos laboratoriais e de campo, e os resultados analisados através de uma abordagem mecanístico-empírica. Dois pavimentos experimentais com revestimentos de solo-cal foram construídos e monitorados próximo a Cebollatí, leste do Uruguai. Foram realizados ensaios de caracterização e comportamento mecânico do solo e de misturas de solo e cal, variando-se o teor de cal, o tempo de cura e a energia de compactação. Realizaram-se ensaios de módulo de resiliência, para o qual foi projetado, montado e operado o primeiro equipamento de ensaios de carga repetida na compressão triaxial do Uruguai. Também foram realizados ensaios de fadiga na compressão diametral para o solo modificado com 3% e 5% de cal, curado por 28 e 150 dias. Para entender o comportamento das camadas de solo modificado com cal submetidas ao tráfego, realizou-se uma análise conjunta dos resultados laboratoriais e do monitoramento dos trechos experimentais, com uso de modelos computacionais. Apesar das limitações construtivas, de terem sido liberados ao tráfego em plena safra e das más condições de drenagem da região, após 5 anos de trafego, os pavimentos não mostram trincas de fadiga ou afundamentos nas trilhas de roda. Assim, a pavimentação de estradas de baixo volume de tráfego em regiões arrozeiras com revestimentos de solo local modificado com cal provou ser uma alternativa economicamente vantajosa, por reduzir custos de construção e manutenção, e sustentável, por preservar materiais não-renováveis, como solos e rochas.Soils in rice plantation areas generally present geotechnical characteristics unsuitable for use as primary wearing course of roads. Because of that, it is necessary to import materials from distant sites, a solution that, besides increasing construction cost, is rarely long-lasting. In this thesis a research on paving low volume roads with lime modified local soils is reported, in order to present an alternative solution to that problem. Both laboratory and field studies were carried out and the results were analyzed by means of a mechanistic-empirical approach. Two test sections with wearing courses made of lime modified soil were built and monitored close to Cebollatí, a village in the east of Uruguay. Previously, laboratory characterization and mechanical tests on samples of the sedimentary soil were carried out. Lime contents for mixtures were determined and the stress-strain-strength behavior of mixes with different levels of lime content, curing time and compaction energy was studied. In order to analyze the elastic behavior of the lime modified soil under traffic, resilient modulus tests were carried out. This motivated the design, assembly and use of the first equipment for triaxial compression repeated loading tests in Uruguay. Besides, stress controlled fatigue tests were performed on cylindrical specimens of soil modified with 3% and 5% of lime, cured for 28 and 150 days. The results of laboratory tests and field monitoring were analyzed using computational models. In spite of the difficulties faced during pavements construction, including heavy traffic in early days, and the poor drainage, after 5 years of service no cracks or ruts are seen on top of the test pavements. Therefore, paving low volume roads in rice plantation areas with lime modified wearing courses has proved to be a cost-effective alternative, reducing construction and maintenance costs, and a sustainable practice, preserving non-renewable materials such as rocks and soils.
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Vlček, Radek. "Ocelová konstrukce mostu na pozemní komunikaci." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240323.
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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.
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Bartholomeu, Daniela Bacchi. "Quantificação dos impactos econômicos e ambientais decorrentes do estado de conservação das rodovias brasileiras." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11132/tde-08052008-172034/.
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Devido à importância do modal rodoviário para a economia brasileira no que diz respeito à sua participação na matriz de transporte de cargas, à elevada participação no consumo de combustíveis fósseis (óleo diesel) e nas emissões de CO2, esta Tese avaliou se rodovias em melhores estados de conservação implicam benefícios econômicos e ambientais. Os benefícios econômicos disseram respeito à avaliação dos seguintes parâmetros: consumo de combustível, tempo de viagem e gasto com manutenção do veículo. Já os benefícios ambientais referiram-se às reduções das externalidades negativas resultantes da diminuição nas emissões de CO2. Foram realizadas coletas de dados primários relacionados ao desempenho observado em caminhões em rodovias com diferentes condições de infra-estrutura. Nesse sentido, foram conduzidos dois conjuntos de experimentos, envolvendo rotas e tipos diferentes de caminhões, aos quais foram acoplados computadores de bordo para auxiliar na coleta dos dados. O primeiro conjunto de experimentos envolveu quatro rotas, as quais foram percorridas por um caminhão Volvo FH12, fabricado em 2004. Num total de 48 viagens, foram observados o consumo de combustível, e o perfil das velocidades em cada trajeto. Os resultados indicaram a existência de benefícios econômicos e ambientais para as rotas em melhor estado de conservação. No segundo conjunto de experimentos, foram selecionadas duas rotas em diferentes estados de conservação., nas quais dois caminhões de fabricantes distintos (Scania R124-420 e MB 1944S) realizaram um total de 40 viagens. Nesses experimentos, também foram comparados os resultados observados em cada tipo de veículo, tendo sido possível concluir que o tipo de tecnologia apenas impactou no consumo de combustível. Finalmente, os dados dos dois conjuntos de experimentos foram agregados, a fim de estimar valores mais próximos à realidade, já que na prática, há diversos tipos de modelos e fabricantes de caminhão. Ainda assim, os resultados obtidos confirmam a existência de benefícios econômicos e ambientais resultantes de viagens em rotas com melhor infra-estrutura: há um aumento na eficiência energética em rotas melhores, implicando menor consumo de combustível e menores níveis de emissão de CO2. A análise estatística dos resultados sugeriu que, em geral, os dados relacionados ao consumo de combustível eram significativos ao nível de significância de 5%, rejeitando a hipótese nula de que o consumo médio das rotas em piores estados de conservação é estatisticamente igual ao consumo médio observado em rotas com melhores condições. Portanto, tratou-se de indicação em favor da hipótese alternativa, de que o consumo médio observado em rotas piores é maior do que aquele em rotas melhores.Due to importance of the road transportation for the Brazilian economy related to its participation in the matrix of load transport, to its high participation in the fossil fuels consumption (diesel) and in the CO2 emissions, this study evaluated if highways in better state of conservation imply in economic and environmental benefits. The economic benefits were related to the evaluation of the following parameters: fuel consumption, duration of the trip and expenses on vehicle maintenance. The environmental benefits related to the CO2 emissions reduction. It was collected primary data related to the performance observed in trucks on highways with different infrastructure conditions. In this aspect, it was carried out two sets of experiments, involving different routes and types of trucks, to which cutting edge computers were connect to assist the collection of the data. The first set of experiments involved four routes covered by a Volvo FH12 truck, manufactured in 2004. In a total of 48 trips, the fuel consumption, and the velocity profile in each passage were observed. The results showed the existence of economic and environmental benefits in the routes with better conservation. In the second set of experiments, two routes in different states of conservation were selected, in which two trucks from distinct manufacturers (Scania R124-420 and MB 1944S) performed a total of 40 trips. In these experiments, the results observed in each type of vehicle were compared, which allowed to conclude that the type of technology only impacted on the fuel consumption. Finally, the data of the two sets of experiments were aggregated, in order to approximate the values to the reality, once in reality there are several types of truck models and manufacturers. Still, the results confirm the existence of economic and environmental benefits deriving from trips in routes with better infrastructure: there is a gain in energy efficiency, resulting in less fuel consumption and lower levels of CO2 emissions. The statistical analysis of the results suggested that, in general, the data related to the fuel consumption were significant to the level of significance of 5%, rejecting the null hypothesis that the average fuel consumption in the routes in worse states of conservation is statistically equal to that observed in routes in better condition. Therefore, it is indicated that the alternative hypothesis is significant that the observed average consumption in worse routes is bigger than that observed in better routes.
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Salvia, Emilie. "Impact de la charge émotionnelle sur l’activité neurophysiologique et les processus de prise de décision : application à la conduite automobile." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10325/document.
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L’activité neurovégétative est un corrélat de la charge mentale et émotionnelle, même lorsque les stimulations sontbrèves et de faible intensité. Elle est notamment sensible à la difficulté perçue mais aussi à une forme particulièred’induction affective, l’injustice. Par conséquent, nous avons utilisé ces mesures neurovégétatives comme variablesdépendantes de la charge mentale/émotionnelle subie par les conducteurs automobiles, dans des conditions plus oumoins astreignantes.Un freinage appuyé induit des réponses neurovégétatives longues et amples, corrélat d’une charge importante. Lafocalisation de l’attention est élevée dans des situations de conduite stressantes, nécessaire pour répondre auchangement possible de la couleur d’un feu tricolore.Nous avons montré, à partir d’enregistrements magnétoencéphalographiques, que sous forte contrainte temporelle,les conducteurs qui avaient tendance à enfreindre les feux présentaient une activation plus élevée au niveau ducortex dorsolatéral gauche. Ils opéraient en permanence un compromis entre le respect simultané du code de laroute et des consignes expérimentales ce qui complexifiait la sélection de la réponse motrice.L’activité végétative s’avère être un témoin fiable de l’activité centrale. L’activation du cortex cingulaire antérieurgauche semble être à l’origine d’une diminution de l’activité électrodermale et cardiaque.Du fait de l’altération de leurs capacités cognitives, les seniors pourraient devenir anxieux face à des situations deconduite pourtant considérées comme anodines pour les plus jeunes. Il est nécessaire de leur dispenser desrecommandations simples afin qu’ils abordent la route plus sereinementAutonomic activity is a correlate of mental and emotional load, even when stimulations are brief and of low intensity.This activity is especially sensitive to the perceived difficulty, but also to a particular form of emotional induction, theinjustice. Therefore, we used these autonomic measures as dependent variables of mental/emotional loadundergone by drivers, under more or less demanding conditions.A heavy braking elicited long and ample autonomic responses, correlate of a strong load. The focus of attention wasgreater in stressful driving conditions, needed to get ready to respond to the possible change of the color of thetraffic light.We showed, from magnetoencephalographic recordings, that under high time pressure, drivers who tended to breakthe lights showed higher activation in the left dorsolateral prefrontal cortex. They continuously operated a trade-offbetween the simultaneous respect of the traffic law and of the experimental instructions thus making the motorresponse selection harder.We also evidenced that the autonomic activity reliably paralleled the central activity. The activation of the leftanterior cingulate cortex decreased both electrodermal and cardiac activities.Due to their impaired cognitive abilities, ageing citizens might become anxious during driving situations consideredbenign by young drivers. It is necessary to provide them simple recommendations in order that they address the roadmore serenely
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Fall, Meïssa. "Identification et caractérisation mécanique de graveleux latéritiques du Sénégal : application au domaine routier." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL119N.
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Les sols latéritiques compactés sont très largement employés comme remblais et matériaux de construction routière dans la plupart des pays tropicaux. Certaines caractéristiques techniques habituelles, sont déjà bien connues et ont fait l'objet d'études antérieures. Le travail actuel porte sur l'examen plus détaillé du comportement mécanique de trois graveleux latéritiques du Sénégal occidental compactes à l'optimum Proctor modifié. L'étude commence par une partie bibliographique qui traite de la formation et de la genèse des sols résiduels tropicaux. Par la suite, on aborde l'utilisation de ce matériau dans les travaux routiers, les différentes spécifications routières qui existent sur ce genre de sols et enfin quelques études faites sur les moyens de leurs identifications géotechniques et la connaissance de leurs propriétés geomécaniques. La deuxième partie du travail est consacrée à une étude statistique sur une banque de données géotechniques. Cette étude dégage d'abord des généralités sur les latérites du Sénégal et aboutit par une analyse de données statistiques qui conclut par la proposition de nouvelles spécifications routières avec les graveleux latéritiques du Sénégal. L'étude des interconnexions simples et multiples avec le CBR (recherches de corrélations entre le CBR et les caractéristiques physiques d'identification), montre que le facteur de portance est indépendant des autres caractéristiques. Une bonne évaluation de l'indice CBR passerait par une meilleure connaissance des qualités mécaniques de ces sols. La troisième partie de la thèse est expérimentale. Nous avons utilisé trois sols latéritiques compactés à l'optimum Proctor modifié et pour lesquels des essais triaxiaux ciu ont été faits sous des sollicitations monotones et cycliques. Une évaluation préliminaire a été faite à la boite de cisaillement de grande taille et montre des pertes de caractéristiques mécaniques en passant de l'état non imbibé à l'état imbibé, selon les conditions de l'essai CBR. Le comportement des sols est différent selon que l'on soit sous faibles contraintes (50 à 150 kpa) ou sous grandes contraintes (200 à 600 kpa), ce phénomène étant lié aux paramètres d'état initiaux. L'approche sous chargements répétés a montre que ces sols sont assez performants dans les conditions de variation de teneur en eau faible
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Hollý, Tomáš. "SO 217 Most přes řeku Morávku v km 6.205." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225523.
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The subject of the thesis is to design and consider steel superstructure of a composite steel-concrete road bridge. It is a continuous beam with seven spans of 36,0 + 57,0 + 75,0 + 90,0 + 75,0 + 57,0 + 36,0 = 426 meters. The superstructure consists of welded I-beams, which pass into closed box girder. The calculations take into account the construction phase.
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Vetešník, Pavel. "Výpočtové porovnání ojnic zážehových motorů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-377364.
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Diploma work is focused on computational comparison of con-rod of spark ignition four-cylinder engine with volume 1289 cubic centimeters and con-rod of spark ignition three-cylinder engine with volume 1198 cubic centimeters. 3-D models of inspected con-rods were based on real shape. Force loads effects were established after kinematic and dynamic analysis. Stress analysis was made for these force loads effects in selected cases with help of Finite element method. Two con-rods were compared by using of these results.
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Cseh, Csaba. "Analýza napjatosti ojnice motoru se zahrnutím vlivu ojničních šroubů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-377358.
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Csaba CSEH Engine Connecting Rod Analysis Including Bolts Influence DW, ITE, 2008, 75 pp, 88 fig. The aim of my diploma work is a stress analysis in the material of a connecting rod during a stationary engine regime. Dynamic forces from the connecting rod‘s motion and the forces acting on the bolts are included in the calculations. The whole stress analysis is based on a FEM designed application on a model, that was created in a CAD system package according to the real component.
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Khoueiry, Nicole. "Study of granular platforms behaviour over soft subgrade reinforced by geosynthetics : Experimental and numerical approaches." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI027.
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Les géosynthétiques sont utilisés depuis les années 70 dans le renforcement des plateformes granulaires reposant sur des sols de faible portance pour des applications de routes non revêtues. La complexité des mécanismes développés et la diversité des produits de renforcement nécessitent encore d’étudier ces plateformes renforcées. Un essai au laboratoire permettant de tester des plateformes à échelle réelle a été développé. Une plateforme granulaire non revêtue reposant sur un sol de faible portance a été reproduite. Un protocole de mise en place de ce sol a été élaboré pour assurer son homogénéité et la répétabilité des essais. Une instrumentation spécifique a été développée pour collecter le maximum de mesures utiles pour l’interprétation du transfert de charge et du comportement des géogrilles utilisées. Trois types de géogrille ont été testées : une géogrille extrudée et deux géogrilles tricotées de rigidité différente. Après de nombreux essais de faisabilité, dix essais ont été effectués sous un chargement cyclique sur plaque circulaire, la plateforme testée a été placée dans un banc d’essai de 1,8 m de large, 1,9 m de long et 1,1 m de haut. Sur la base du même protocole de mise en œuvre, des essais de circulation avec un Simulateur Accélérateur de Traffic (SAT) ont été effectués. Ce simulateur a été spécifiquement conçu et construit pour cette application. Pour ces essais, la plateforme testée a été placée dans le banc d’essai allongé à 5 m. La plateforme a été soumise à deux types de sollicitations : un chargement cyclique sur plaque et un chargement de circulation. Des essais de répétabilité ont permis de vérifier le protocole mis en place. A partir des essais, plusieurs observations ont pu être faites sur le comportement des plateformes granulaires, le sol peu porteur, et sur l’efficacité du renforcement. De plus, ces essais ont permis de montrer que le chargement de circulation est beaucoup plus endommageant que le chargement sur plaque. Parallèlement à ces essais, un modèle numérique a été développé en se basant sur la méthode des différences finies avec le logiciel FLAC 3D. Cette modélisation a permis de prédire le comportement de la plateforme sous le premier chargement de plaqueGeosynthetics were used since 1970 in the base course reinforcement supported by soft subgrade in unpaved road application. The various factors and parameters influencing the dominant mechanism and its relative contribution on the platform improvement explain the need of more investigations in this topic. In this research work, large-scale laboratory test was developed to study the reinforcement contribution in the unpaved road improvement. Therefore, an unpaved platform was built of 600 mm of artificial subgrade supporting a base course layer. A detailed experimental Protocol was established regarding the soil preparation, the installation and the soils compaction procedure to reproduce the site conditions and insure the platform repeatability for each test. Three geosynthetics were tested first under a cyclic plate load test. Cyclic load was performed on the prepared platform, with a maximum load of 40 kN resulting in a maximum applied pressure of 560 kPa. The platform was subjected to 10,000 cycles with a frequency of 0.77 Hz. An advanced and complete soil instrumentation was provided in order to collect the maximum data needed for thorough analysis. Quality control tests were performed before each test to verify the soil layers homogeneity and properties. Two base course thicknesses were tested under this test condition, 350 and 220 mm. Once the developed protocol was confirmed under the circular plate load tests, further tests using the Simulator Accelerator of Traffic (SAT) were performed. Indeed, the laboratory prepared platform was placed in a larger box of 1.8 m in large, 5 m in length and 1.1 m in height. The prepared platform was subjected to two solicitations: a particular plate and traffic load. The Simulator Accelerator of Traffic was developed specially for this application. A machine that simulates the traffic load under an effective length of 2 m and a velocity of 4 km/h. The two areas were instrumented: the area under the circulation load, and the area under the plat load, located aside. In addition, a numerical model based on the differential element method using FLAC 3D was developed. The model simulated the circular plate load test with the same platform configuration under monotonic load. The results were compared to the first monotonic load applied on the rigid plate experimentally
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Bovin, Jimmy. "Rapid Exchange Solution (RES) : En mekanisk omlastningslösning för horisontell överföring av containrar mellan olika transportmedel." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-28645.
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Detta examensarbete genomfördes våren 2013 på Karlstads universitet där TD Rail & Industry i Västerås stod som uppdragsgivare. Projektet innefattade att kartlägga nuvarande omlastningslösningar av enhetslaster mellan järnvägstransporter och vägtransporter, och utarbeta en konceptuell omlastningslösning med fokus på att öka järnvägstransporternas flexibilitet gentemot vägtransporterna. Där vikten lades på att utarbeta ett välarbetat helhetskoncept. Projektet genomfördes med designprocessen som grund och innehöll bland annat momenten; förstudie, kravspecificering, idégenerering, konceptval m.m. Resultatet blev en vidareutveckling av det redan befintliga systemet CCT som bygger på horisontell överföringsteknik och möjliggör därför omlastning av enhetslaster direkt under kontaktledning. Skillnaden mellan RES och CCT är att man tagit bort ombyggnationen av tågvagn och lastbilschassi, som var en av CCTs stora svagheter, genom två hydrauliska ”teknikplattor”. Tack vare detta tillsammans med sin låga investeringskostnad/driftkostnad öppnar RES nya möjligheter för omlastning på fler strategiska punkter direkt utmed järnvägsnätet och därmed ökar järnvägstransporternas flexibilitet. Som vidareutveckling av RES föreslås ett samarbete med CCT där man initialt utför mer detaljerade beräkningar på teknikplattorna.This Bachelor of Science thesis was carried out in spring 2013 at Karlstad University for a company called TD Rail and Industry placed in Västerås, Sweden. The project included mapping of current transferring solutions of unit loads between railway and road transports, and the development of a conceptual transferring solution with the focus to increase the flexibility of the railway transport. The importance was to develop a well-made overall concept rather than small detailed parts of it. The project followed the design process methodology and included parts like: pre-study, requirements specification, idea generation, concept selection etc.The result was a further development of an already existing system called CCT based on horizontal transferring technology and therefore allow transferring of units directly under the overhead contact line. Thanks to this, together with its low investment / operating costs RES opens new opportunities for additional strategic transferring places along the railway, thereby increasing the flexibility of rail transports. The difference between RES and CCT is that you no longer need to rebuild the railway cars or the truckchassis , which was one of CCTs major weaknesses, instead the lifting mechanism is replaced by two hydraulic "technique plates". As a further development of the RES a partnership with CCT is proposed.
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Běloušek, Ondřej. "Úprava MÚK silnic R46 a II/428 u Vyškova." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225630.
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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.
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Zago, João Paulo. "Estudo da deformação permanente de três solos típicos de subleitos rodoviários de Santa Maria - RS." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/12036.
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Studies conducted in 2016 show that 58% of the highways in Brazil presents any
deficiency in the pavement, signaling or in its geometry. These deficiencies are, on
average, the cause for about 6% of the accidents and for the increase of the
operational cust by 91,6%. Among them we can stress the permanent deformation,
the so called wheel tracks, which is harmful to the dynamic of the loads, to the
comfort provided by the pavement, increasing its risk. To the correct design of the
pavement it is very important to better know the characteristics of the materials to be
used. In this context, stands out the subgrade, the foundation for the whole structure
of the pavement, which one is studied in the present reseach by considering three
typical soils used as highway subgrade in Santa Maria, Rio Grande do Sul State, and
having the permanent deformations as the main focus. The metodology aplied in this
work consisted in the location, sampling and characterization of the soil fields, lab
tests and empirical machanistic design. Besides the physical, chemical and
mechanical characterizations, it was performed the repeated triaxial load test aiming
to obtain the resilient modulus and the permanent deformation parameters, according
to the Brazilian Petroleum Corporation Manual (PETROBRAS). The Resilient
Modulus model presented the better results with frequencies of 1 Hz and 2 Hz, and
the presence of silt in one of the soils affected its resilient behaviour. The permanent
deformation tests were performed with the frequency of 2 Hz and 150.000 load
cicles. The average statistic correlation, according to Guimaraes (2009)´s
methodology, was 0.91, bigger than the one provided by the Monismith and
Barksdale´s models. However, the dominance of fine grained soils, along with low
compactation energy, lead to a higher deformation rates, motivating the use of
intermediate energy. With this new approach the permanent deformation was
reduced 40% and the resilient modulus increased 78,8%. However, the numerical
simulation according to the mechanistic approach, and using the layer thickness
obtained from the Departamento Nacional de Infraestrutura de Transportes (DNIT)
method, under 8,2 ton standard axle load, showed that the wheel tracks deeping
would be small, based on the low stresses observed in the subgrade. On the other
hand, the fatigue behaviour presented an inferior performance, reducing the project´s
useful life. It was observed the presence of shakedown in the ranges A, B and C.Pesquisas realizadas no ano de 2016 mostram que 58,2 % das rodovias de todo o país apresentam alguma deficiência no pavimento, na sinalização ou na geometria da via. Em média, esses defeitos são responsáveis por cerca de 6% do número de acidentes, além de aumentar o custo operacional das vias em até 91,6%. Dentre essas anomalias, destaca-se a deformação permanente denominada de afundamento na trilha de roda (ATR), que prejudica a dinâmica das cargas, afeta o conforto ao rolamento e causa risco à segurança. Para o adequado dimensionamento de um pavimento, é fundamental o conhecimento dos materiais que o compõem. Neste contexto, destaca-se o subleito, por ser a fundação sobre a qual são assentes todas as camadas, motivo pelo qual o objetivo geral desta pesquisa é analisar três solos típicos de subleitos rodoviários de Santa Maria, estado do Rio Grande do Sul, em especial quanto aos parâmetros de deformação permanente. A metodologia aplicada neste trabalho consistiu na localização, coleta e caracterização das jazidas de solos, realização de ensaios laboratoriais e dimensionamento mecanístico - empírico. Assim, além da caracterização física, química e mecânica, foram realizados ensaios triaxiais de cargas repetidas para obtenção do módulo de resiliência e dos parâmetros de deformação permanente, segundo recomendações do manual de execução de trechos monitorados da empresa Petróleo Brasileiro Sociedade Anônima (PETROBRAS). O modelo composto do módulo de resiliência apresentou os melhores resultados, a partir de ensaios com frequência de 1 Hz e 2 Hz, sendo que a presença de silte em um dos solos afetou seu comportamento resiliente. Os ensaios de deformação permanente foram conduzidos a 2 Hz, com 150.000 ciclos de aplicação de carga, cuja correlação estatística média, empregando a metodologia de Guimarães (2009), foi de 0,91 – superior a dos modelos de Monismith e Barksdale. Entretanto, a predominância de materiais finos, aliada à baixa energia de compactação (normal), resultaram em elevadas taxas de deformação, o que motivou o estudo de um dos solos também com uso da energia intermediária. Esse procedimento reduziu a deformação permanente em 40% e elevou o módulo de resiliência em 78,8%. Entretanto, a simulação numérica do pavimento sob a ótica mecanicista, a partir das espessuras calculadas pelo método do Departamento Nacional de Infraestrutura de Transportes (DNIT), aplicando-se a carga padrão de 8,2 toneladas, mostrou que o ATR seria pequeno, em face das baixas tensões atuantes no subleito, em contraposição ao desempenho à fadiga, que reduziu sensivelmente a vida útil de projeto. Constatouse a ocorrência de shakedown nos domínios A, B e C.
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Vinay, Kumar Nerella V. "An Analysis on Vehicular Exhaust Emissions from Transit Buses Running on Biodiesel Blends." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271886446.
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Barreto, Marco Antonio Zanussi. "Dinâmica longitudinal : efeitos da geometria de suspensão nas mudanças de atitude da massa suspensa e os esforços nos elementos da suspensão." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-22122005-165842/.
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Este trabalho tem como objetivo estudar a influência da geometria de suspensão do veículo nas atitudes da massa suspensa. Apresenta um confronto entre obras e autores e está segmentada em três partes; onde na primeira parte são definidos os conceitos básicos como dive, squat, lift, anti-dive, anti-squat, anti-lift e equivalente trailing-arm; na segunda parte são apresentadas as limitações e os novos conceitos definidos por R. S. Sharp e na terceira parte é apresentado o modelo dinâmico bidimensional introduzido por Fu-Cheng Wang. Apresenta um modelo virtual em sistema de multi-corpos desenvolvido no programa ADAMS, com todos os subsistemas que compõe um veículo completo. Inova ao trazer como objeto de estudo um veículo de competição (fórmula SAE) que possui como particularidade o sistema de suspensão push-rod. Surpreende com os resultados obtidos, pois, contrariam os conceitos básicos encontrados na maioria dos livrosThis work has objective study the influence of suspension geometry on the sprung mass attitudes. It presents a confrontation among works and authors and this segmented in three parts; where in the first part the basic concepts are defined, dive, squat, lift, anti-dive, anti-squat, anti-lift and equivalent trailing-arm; in the second part the limitations are presented and the new concepts are defined for R. S. Sharp and in the third part are presented the bidimensional dynamic model introduced by Fu-Cheng Wang. It presents a virtual model in system of multi-bodies developed in the program ADAMS, with all the subsystems that composes a complete vehicle. It innovates when bringing such object to study one vehicle of competition (formula SAE) that it has a particularity suspension system push-rod. It surprises with results because its opposite of the basic concepts which is present in the majority of books
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Zemánek, Tomáš. "Spojitá betonová mostní konstrukce." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372029.
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The diploma thesis is focused on solving road bridge situated between Roudno and Razová village over the water basin Slezská Harta. Before the design itself 3 studies were created and compared together. The selected variant is a continuous box girder with inclined walls, post-tensioned by bonded cables. The girder of a total lenght 148,0 m and width 13,6 m is divided into three spans. Height of the girder is 3,3 m. A detailed structural design, including construction limit state assessment, prestress design and time dependent analysis verification is processed. The design and the assessments of temporary and permanent situations are made according to valid standarts and regulations. Drawings and vizualizations are parts of the diploma thesis.
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Navrátil, Ondřej. "Objekt pro administrativmí a logistické účely." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225455.
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Design of a steel supporting structure for one-storeyed hall based on ground plan of 60 x 80 m, clear height 10 m and total height 13,3 m. In the front part there is along the whole widht designed two-storeyed skeleton structure penetrating into the hall. From the second floor rods supported frontal part which exceeds ground plan by 2 m and on the right side is closed by pre-set cylindric structure with radius 8,6 m which covers the right frontal corner of building. The cylindric structure is around its perimeter distanced max 3,6 m from hall grand plan and is supported by posts. Both spaces had saddle roof with 8% slant, gutter edge in height 11,6 m, top line in height 12,8 m. Walls are around perimeter closed by horizontal atic in height of 13,3 m. Shape and dimensional design, load specification – stady, utility, climacic load. Calculation of imide forces and further static dimensioning of the main supporting elements and selected details. Elaboration of design documentation (dosposition, production drawing of the anchorage plan, details definited by project supervizor).
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Bílek, Tomáš. "Vícepodlažní administrativní budova ve Zlíně." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225572.
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Design of a new steel structure administrative building in Zlín. Structure is consist of three parts. The part A is designed of three fields in the transverse direction and five fields in the longitudinal direction. This part is two-storey. The part B is designed of two fields in the transverse direction and three fields in the longitudinal direction. This part is six-storey (five-storey). The part C is designed of two fields in the transverse direction and five fields in the longitudinal direction. This part is four-storey (three, two-storey). In both directions in all parts of the building is the distance between the columns in all fields of 6,0 meters. Structural elevation of all floors is 3,5 meters. Shape and dimension design. Fixed, utility, climatic load. The purpose is confrontation of inner forces and dimensioning of main supporting elements in three variations of structure. Comparsion of variations. More detailed static calculation, drawings for the selected variant. Detailed drawings for part of building.
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Lečbych, Antonín. "Trojlodní objekt pro průmyslovou výrobu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227558.
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The thesis contains the design and assessment of three-aisled steel building for small metal production. Supporting span of construction hall is 9, 18 and 9 m. In the middle wing is situated bridge crane with capacity of 2 tons. The estimated location of the object is Luhačovice. The initial design concept was specified by supervisor (as the idea of the investor/architect), for which was did static and structural solution and assembly details. For selected option was made a calculation of supporting structures and selected assembly details. The hall has a rectangular floor plan of 36x36m and ridge height is 9 m. The central wing is made of steel and side extensions are made of glued laminated timber.
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Kadlubiec, Janusz. "Dlouhodobé posuzování vozovek opravených recyklací podkladů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225491.
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My work deals with monitoring communications sections, which were renovated zrecyklováním existing surface. I documented these communications and to assess their condition after the time of use. Subscribed sections I put into the database PMS.
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Šašinka, Jakub. "Ocelová konstrukce vojenského muzea." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227198.
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The diploma thesis describes the design and assessment of steel structure of the roofing of the military museum in Králíky. The supporting structure of hall is 40.00 meters span. The total layout are 55.93 x 72.04 m, building height 11.43 m, 16.11 m pylon height. Main construction material is steel, grade S355, secondary constructions are made from steel grade S235, rods are made from steel grade S460. I did optimization of steel structure and chose the best option. For this option I made detailed structural analysis. It is prepared by static analysis of the main load-bearing parts of the structure, including joints and details. The supporting structure of hall consists in the transverse direction from the curved spatial lattice structure made of steel circular tubes which hang on rods on a sloped pylon. Part of the report is open-air roofing.
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Tobek, Miroslav. "Řešení dopravy v centru Havlíčkova Brodu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225922.
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The aim of this diploma thesis is the solution of the traffic situation in the city center of Havlíčkův Brod. Mainly the ground road number II/150 adjustment, which consist in the modification of the two-way traffic to one-way traffic organization in the streets Dolní, Žižkova and Na Ostrově by using the analogy of a roundabout layout, is solved within this thesis. All mentioned modifications simplify the traffic situation, improve the orientation and increase the security and the traffic flow mainly in relation to pedestrians and cyclists. Another part of this thesis is focused on revitalization of the public spaces in front of the community center called Ostrov and junction of existing cycle tracks situated on the both banks of the Sázava river. In relation to this topic the adjustment of rainwater sewerage system, low-voltage above ground network, public lighting, communication electric cables, fire brigade signal lights and low-pressure gas pipeline is also solved.
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Nair, Asha M. "Behaviour Of Geosynthetic Reinforced Soil–Aggregate Systems Under Static, Repeated And Cyclic Loads." Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2521.
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Efficient road network and connectivity play vital role in the development of any country. Majority of the rural roads are unpaved and connectivity of rural roads is always a major challenge. Unpaved roads are also used for temporary transportation facilities like access roads, haul roads for mines, forest roads and parking lots. Since these roads do not have asphalt surfacing, they are subjected to early failures due to distresses like rutting, pot holes and depressions . Stabilization of unpaved roads using geosynthetics has been proved to be promising in increasing the lifespan of these roads because they facilitate economical, aesthetic and effective design of the roads. Inclusion of geosynthetic layers at the interface of subgrade soil and granular sub-base, reduces the surface heave, ensures a better stress distribution and reduces the stresses transferred to the subgrade soil, as demonstrated by earlier researchers.
Wide variety of geosynthetics like woven and nonwoven geotextiles, uniaxial and biaxial geogrids and geocells are used as reinforcement in road sections. Geotextiles improve the strength by interfacial friction, lateral restraint and membrane effect. Geogrids provide additional benefit of interlocking. Geocells are honeycomb shaped geosynthetic cellular confining systems filled with aggregates in which the reinforcement action is derived not only by friction and interlocking, but also by confinement. Load-deformation characteristics of reinforced soil-aggregate systems under static, repeated and cyclic loads is a potential topic of interest considering the fact that the design of geosynthetic reinforced unpaved roads is still under development and experimentation.
The objective of the present study is to understand the beneficial use of geosynthetics in unpaved roads and to provide clear insight into the influence of geosynthetics on the cyclic loading characteristics of unpaved roads through laboratory experiments. California Bearing Ratio (CBR) tests were carried out on unreinforced and reinforced soil-aggregate systems to study the effect of various parameters such as type of reinforcement, form of reinforcement, quantity of reinforcement, and water content of the subgrade soil on the load-penetration response of the various systems. Modified CBR tests were also carried out to understand the influence of boundary of the mould and anchorage of reinforcement on the behavior of reinforced soil-aggregate systems. Behavior of unreinforced and reinforced soil-aggregate systems under repeated and cyclic loading is also studied to understand the resilience of the composite systems. From the measured stress-strain response, the elastic and plastic strains developed in various systems are compared. Different moduli such as secant modulus, cyclic modulus and resilient modulus are computed for different systems and compared.
To investigate the effectiveness of geosynthetics in improving the load - bearing capacity, repeated load tests were carried out on model sections of unpaved road constructed in a steel test tank of size 750 mm × 750 mm × 620 mm. The effect of various parameters like the form of reinforcement, quantity of reinforcement, height of geocell layer and the position of geocell layer on the load-deformation behaviour of the unpaved model road sections was studied. Static and cyclic triaxial tests were carried out on unreinforced and reinforced granular sub-base materials to understand their stress strain behavior under static and cyclic loading conditions. The influence of quantity and form of reinforcement on the stress-strain behaviour of these materials was studied.
From the studies it is observed that the use of reinforcement increases the CBR value of the soil-aggregate systems. Studies with two different sizes of CBR moulds indicated that the boundary effect in the standard CBR mould leads to the overestimation of the CBR value, resulting in unconservative design of road sections. Providing anchorage to the reinforcement in CBR tests did not produce an appreciable change in the load-penetration behavior.
From the repeated load tests it was observed that the reinforced systems did not show any improvement in the load-deformation behaviour at low levels of rut depth. At higher rut depths, the reinforced systems developed less plastic settlements and more elastic settlements and low resilient modulus compared to unreinforced systems. From the model tests on unpaved road sections, it was observed that the improvement in the cyclic load resistance of the road due to the inclusion of geocell layer depends on the height of the geocell layer and its position. Increasing the height of geocell layer resulted in improved performance up to certain height of the geocell layer, beyond which, further increase in the height reduced the load resistance because of the inadequate granular overlay thickness and inadequate compaction of aggregate within the geocell pockets. Static and cyclic triaxial tests showed that the geogrid and geocell reinforced granular sub-base material sustained higher peak stresses and exhibited increase in modulus compared to the unreinforced specimens. Results of element and model tests carried out in this study gave important insight into the load-deformation characteristics of reinforced soil-aggregate systems under static, repeated and dynamic loads. The results provide guidelines regarding the selection of type, quantity and configuration of geosynthetic reinforcement while designing unpaved roads and the expected performance of these reinforced unpaved roads.
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Vogeler, Isabell. "Road Load Determination in a Wind Tunnel." Phd thesis, 2021. https://tuprints.ulb.tu-darmstadt.de/19370/1/Dissertation_Vogeler_final.pdf.
Full textAbstract:
The present study contains a detailed analysis of the road load of a vehicle, the single road load components and their most important influencing factors. Furthermore, two different methods are described in detail, which are allowed by law. The first method uses coastdown runs on a proving ground, to determine the road load of a vehicle. This method is called coastdown method. However, the result quality using this method strongly depends on environmental influencing factors, but also on the road surface conditions. With the inception of WLTP (Worldwide harmonized Light vehicles Test Procedures) in September 2017, it is now possible for the first time to determine the vehicle road load using the so-called wind tunnel method. According to this method, the aerodynamic drag is measured in the wind tunnel and the remaining components are determined using a flat belt dynamometer.
At the beginning of this study, the flat belt dynamometer of the BMW Group was just in commissioning. Therefore, the test procedure and the influencing factors on the determined road load, such as test bench temperature, vehicle position at the test bench, tyre inflation pressure and the additional airstream of the cooling fan, are initially investigated in detail. Due to this analysis, it was found that an additional correction factor is necessary for the wind tunnel method, to simulate the road load existing on a real road. Therefore, the so-called wind tunnel method extended was developed, which contains a further rolling resistance correction factor to simulate this.
Moreover, Untermaierhofer, Petz and Vogeler developed a measurement method which enables the separation of the measurement result of the flat belt dynamometer into its two components rolling resistance and drivetrain losses with one single measurement using a custom-built torque meter. Thus, this method can be used to analyze and develop different vehicle components in vehicle installation position with the flat belt dynamometer in more detail.
Furthermore, the possibility to determine the total road load of a vehicle in a wind tunnel was investigated. With the newly developed AEROLAB method it is possible to determine the road load of a vehicle excluding the residual brake forces using the AEROLAB wind tunnel of the BMW Group. In this study, the missing residual brake forces are determined using the flat belt dynamometer. It is shown that, in contrast to the wind tunnel method, no further correction factor is necessary using the AEROLAB method, to simulate the absolute value of the vehicle road load determined by the coastdown method on a proving ground. It is pointed out that mainly the lower tyre tread temperatures and transmission oil temperatures as well as an additional wheel ventilation resistance are responsible for the higher road load measured with the AEROLAB method. The measurement of the missing residual brake forces in the wind tunnel is not possible at present, because extensive constructional measures would be necessary initially. If these were implemented, it would be possible to determine the total road load of a vehicle under laboratory conditions at one single test bench for the first time. From a business perspective, using this method represents a potential to reduce test bench and proving ground booking times as well as vehicle transportation.
The total analysis of the road load determination according to these methods is completed with an error calculation using GUM (Guide to the expression of Uncertainty in Measurement).
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Baiz, Sarah. "Using Road Weather Information Systems (RWIS) to optimize the Scheduling of Load Restrictions on Northern Ontario's Low-Volume Highways." Thesis, 2007. http://hdl.handle.net/10012/3248.
Full textAbstract:
Covering the Northern part of the Province, Ontario’s low-volume roads provide a link from remote resource areas to markets. Thus, preserving this transportation asset from the two main sources of pavement deterioration, namely traffic loading and the environment is extremely critical to the movement of goods and to the economy. In particular, Northern Ontario’s secondary highways are challenged by a combination of heavy, low frequency traffic loading and a high number of freeze-thaw cycles for which most of these highways have not been structurally designed. Therefore they experience environmental damage and premature traffic-induced deterioration.
To cope with this issue, the Ontario Ministry of Transportation places Spring Load Restrictions (SLR) every year during spring-thaw. For economic reasons, the duration of SLRs is usually fixed in advance and is not applied proactively or according to conditions in a particular year. This rigidity in the schedule needs to be addressed, as it can translate into economic losses either when the payload is unnecessarily restricted or when pavement deterioration occurs. While the traditional approaches are usually qualitative and rely on visual observations, engineering judgment and historical records to make SLR decisions, the latest approaches resort to climatic and deflection data to better assess the bearing capacity of the roadway.
The main intent of this research was to examine how the use of a predictor for frost formation and thawing could improve the scheduling of load restrictions by tracking the frost-strengthening and thaw-weakening of the pavement structure. Based on field data captured in Northern Ontario, and on a preliminary analysis that found good correlation between frost thickness in the roadway and Road Weather Information Systems (RWIS) variables, more advanced frost and thaw predictors were developed as part of this research and are presented herein. The report outlines how the model was developed, details the calculation algorithms, and proposes an empirical methodology for a systematic site-specific calibration.
This research also involved several experimental and numerical tools, including the use of a Portable Falling Weight Deflectometer (PFWD) to estimate pavement strength during spring thaw, and the use of the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to simulate the impact of SLR on the performance of typical Northern Ontario low volume roads.