• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 4
  • 3
  • 2
  • Tagged with
  • 14
  • 7
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Hierarquização para orientar a manutenção de rodovias não-pavimentadas / To guide the maintenance of non-paved roads

Oliveira, Mário José Garrido de 12 December 2005 (has links)
O trabalho mostra que a distribuição de qualidade de viagem do ponto de vista de quem usa rodovias, o Sistema de Posicionamento Global (GPS) e o Sistema de Informação Geográfica (SIG) podem contribuir para aperfeiçoar o manuseio de informação para hierarquizar necessidades de intervenção, e orientar manutenção de rodovias não-pavimentadas acessível a cidades pequenas do Brasil. Para isso foram estudadas escalas de classificação geradas a partir de análise sobre distribuições de variáveis que descrevem defeitos de rodovias não-pavimentadas em função de opiniões emitidas por habitantes e produtores rurais. O GPS de navegação foi usado para determinar coordenadas de pontos de rodovias. O SIG usado é brasileiro e de domínio público. A argumentação foi obtida em estudo de caso sobre as rodovias de Nova Europa, estado de São Paulo, Brasil. / This dissertation shows that the distribution of trip quality from the point of view of highway users, the Global Positioning System (GPS) and the system of Geographical Information System (GIS) can contribute with information accessible to brazilian small cities administrators to classify the hierarchy of intervention necessities to guide the maintenance of non-paved roads. Scales of classification from analysis on distributions of variables were studied describing non-paved roads defects obtained from the study of the opinions of inhabitants and rural producers. The GPS of navigation was used to determine coordinates of highway points. The GIS used is a brazilian product of public domain. The argument was gotten in a case study on highways from the city of Nova Europa, state of São Paulo, Brazil.
2

Hierarquização para orientar a manutenção de rodovias não-pavimentadas / To guide the maintenance of non-paved roads

Mário José Garrido de Oliveira 12 December 2005 (has links)
O trabalho mostra que a distribuição de qualidade de viagem do ponto de vista de quem usa rodovias, o Sistema de Posicionamento Global (GPS) e o Sistema de Informação Geográfica (SIG) podem contribuir para aperfeiçoar o manuseio de informação para hierarquizar necessidades de intervenção, e orientar manutenção de rodovias não-pavimentadas acessível a cidades pequenas do Brasil. Para isso foram estudadas escalas de classificação geradas a partir de análise sobre distribuições de variáveis que descrevem defeitos de rodovias não-pavimentadas em função de opiniões emitidas por habitantes e produtores rurais. O GPS de navegação foi usado para determinar coordenadas de pontos de rodovias. O SIG usado é brasileiro e de domínio público. A argumentação foi obtida em estudo de caso sobre as rodovias de Nova Europa, estado de São Paulo, Brasil. / This dissertation shows that the distribution of trip quality from the point of view of highway users, the Global Positioning System (GPS) and the system of Geographical Information System (GIS) can contribute with information accessible to brazilian small cities administrators to classify the hierarchy of intervention necessities to guide the maintenance of non-paved roads. Scales of classification from analysis on distributions of variables were studied describing non-paved roads defects obtained from the study of the opinions of inhabitants and rural producers. The GPS of navigation was used to determine coordinates of highway points. The GIS used is a brazilian product of public domain. The argument was gotten in a case study on highways from the city of Nova Europa, state of São Paulo, Brazil.
3

Effect Of Recycled Cement Concrete Content On Rutting Behavior Of Asphalt Concrete

Gul, Waqar Ahmed Waqar 01 August 2008 (has links) (PDF)
Disposed waste materials remained from demolished buildings have been an environmental problem especially for developing countries. Recycled Cement Concrete (RCC) is one of the abundant components of waste materials that include quality aggregates. Use of RCC in asphalt concrete pavements is economically a feasible option as it not only helps in recycling waste materials but also preserves natural resources by fulfilling the demand for quality aggregate in pavement constructions. However, due to variability in RCC characteristics, a detailed evaluation of its effect on asphalt concrete performance is required. In this study, effect of RCC content on rutting potential of asphalt concrete is investigated using laboratory prepared specimens. Rutting susceptibility of the specimens is determined using repeated creep tests performed in the uniaxial stress mode. Because of the aspect ratio requirements for the repeated creep test, the standard Marshall mix design procedures were modified based on the energy concept by changing the compactor device and the applied design number of blows. The modified specimens were tested to determine a number of parameters that can describe the rutting behavior of the tested mixes. The findings indicate that slope constant and flow number give relatively stronger relationships with rutting behavior as compared to the other rutting parameters. While increasing the RCC content yields improved rutting performance for coarse graded specimens, it dramatically reduces the performance for fine graded specimens.
4

Evaluation Of Resilient Modulus Estimation Methods For Asphalt Mixtures Based On Laboratory Measurements

Demirci, Canser 01 May 2010 (has links) (PDF)
Resilient modulus is a property for bound and unbound pavement materials characterizing the elastic behavior of materials under dynamic repeated loading. Resilient modulus is an important design parameter for pavement structures because it represents the structural strength of pavement layers through which the thickness design is based on. In Turkey, the layer thickness design is performed using resilient modulus determined empirically from various published sources. Determining a layer modulus using empirical methods causes inaccurate design solutions, which directly affects the structural performance and the overall cost of pavement construction. In this study, the resilient moduli of bituminous mixtures are measured in the laboratory by the indirect tensile test procedure for eight asphalt concrete samples according to NCHRP and ASTM procedures. The measured moduli of samples based on the two procedures are compared with the predicted values calculated from various empirical methods using aggregate and binder properties. An evaluation of each estimation method is presented on the basis of its accuracy level. The results show that the Witczak predictive equation produces the closest estimation to the modulus of samples for both laboratory measurement methods.
5

Acúmulo e carreamento de poluentes em superfície de estacionamento / Build-up and wash-off of pollutants in surface parking

Pauletti, Luciana Inácio 21 September 2012 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-07T14:06:12Z No. of bitstreams: 2 Dissertação - Luciana Inácio Pauletti - 2012.pdf: 2287630 bytes, checksum: 392dd39420f8918a2239eaf29eea5ee0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-05-07T14:08:33Z (GMT) No. of bitstreams: 2 Dissertação - Luciana Inácio Pauletti - 2012.pdf: 2287630 bytes, checksum: 392dd39420f8918a2239eaf29eea5ee0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-05-07T14:08:33Z (GMT). No. of bitstreams: 2 Dissertação - Luciana Inácio Pauletti - 2012.pdf: 2287630 bytes, checksum: 392dd39420f8918a2239eaf29eea5ee0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2012-09-21 / The stormwater runoff in urban areas is an important source of non-point pollutants. This study aimed to quantify the build-up and wash-off of pollutants, particularly metals, water runoff from a paved surface urban Goiânia. Studies to estimate the processes of build-up and wash-off are still incipient in Brazil. We evaluated twelve plots paved with size of 3m2, located in a public parking lot, where they were analyzed on build-up and wash-off in June and July 2012. To wash-off was used a rainfall simulator in three intensities, 69 mm/h, 109 mm/h and 180 mm/h. Quantitation of accumulation in sampled surfaces determined load per m2 to obtain the coefficient build-up as well as for the analysis of the influence of background dried days before sampling campaigns. The build-up was adjusted at four possible equations for use in models water quality: (1) Linear, (2) Power (3) Exponential, and (4) Michaelis-Menton by obtaining the best fit. The water quality parameters analyzed were used for calculation of Average Concentration Event (CME), building polutogramas, coefficient of wash-off and correlation analyzes. The accumulation rate obtained was, on average, 8.53 g/m2dia, and more days dry, the greater the accumulation of pollutants. Levels of metals were found in all analyzed plots for all simulated events in different periods. There sharp and direct correlation between variables, particularly suspended solids and metals. The intensity of rain on the wash-off was clear, since the simulated rain intensity shifted with greater dirtier. Parameters were obtained for modeling the quality of rainwater. / O presente trabalho teve como objetivo quantificar o acúmulo (build-up) e carreamento (wash-off) de poluentes, principalmente metais, na água do escoamento de uma superfície pavimentada urbana de Goiânia. Os estudos para estimativa dos processos de build-up e wash-off são ainda insipientes no Brasil. Foram avaliadas doze parcelas experimentais asfaltadas, com dimensão de 3m2, situadas em um estacionamento público, onde foram realizadas as determinações de build-up e wash-off nos meses de junho e julho de 2012. Para wash-off foi utilizado um simulador de chuvas em três intensidades, 69 mm/h, 109 mm/h e 180 mm/h. A quantificação do acúmulo nas superfícies amostradas determinou a carga por m2 para obtenção do coeficiente de build-up, bem como para a análise da influência dos dias secos antecedentes antes das campanhas amostrais. O build-up foi ajustado nas quatro equações: (1)Linear, (2)Potencial, (3)Exponencial, e (4)Michaelis-Menton, com a qual se obteve o melhor ajuste. As análises de qualidade de água de escoamento permitiram o cálculo da Concentração Média do Evento (CME), construção de polutogramas, determinação do coeficiente de wash-off e análises de correlação. A taxa de acúmulo obtida foi, em média, de 8,53g/m2dia, sendo que quanto mais dias secos antecedentes à coleta, maior o acúmulo de poluentes. Foram encontrados metais (cromo, cádmio, cobre, chumbo, níquel, zinco, manganês e ferro) em todas as parcelas experimentais para todos os eventos simulados nos diferentes períodos. Verificou-se correlação direta e acentuada entre as variáveis avaliadas, principalmente entre sólidos suspensos e metais. O efeito da intensidade de chuva sobre o wash-off ficou evidente, visto que as chuvas simuladas com maior intensidade deslocaram mais poluentes. Neste estudo foram obtidos parâmetros para a modelagem da qualidade das águas pluviais.
6

Parametric Study On Selected Mathematical Models For Dynamic Creep Behavior Of Asphalt Concrete

Ozturk, Hande Isik 01 December 2007 (has links) (PDF)
Rut formation has long been recognized as a distress mechanism in flexible pavements. One of the causes of rut formation in flexible pavements is permanent deformation of uppermost asphalt concrete layers due to repeatedly applied traffic loading. The long term permanent deformation of asphalt concrete under repeated load is commonly called as dynamic creep. The primary objective of this thesis is to examine dynamic creep behavior of asphalt concrete specimens tested in laboratory and also study some suitable mathematical models for representing dynamic creep behavior. In this study, a set of uniaxial repeated load creep tests were performed on standard Marshall specimens prepared at three different bitumen contents. The effects of bitumen content and test condition parameters on dynamic creep behavior are examined. Among several mathematical creep models suggested by researchers, two well known models and a model proposed by the author are selected for representing the laboratory creep behavior. For each of these models, the interactions of the model parameters with varying bitumen content and test conditions are studied to detect probable definite trends, and to evaluate whether some relations for the model parameters as functions of bitumen content and test conditions can be developed or not. The results of analyses showed that all three mathematical models used in this study are successful in representing the laboratory dynamic creep behavior of asphalt concrete. The Power Model which has only two parameters is found to be the most stable and suitable model for parametric study among the three selected models. More consistent and definite interactions are observed between the parameters of this model and test conditions. However, within the scope of this study, no relations could be developed for the parameters of selected models as functions of bitumen content and test conditions because of limited test data.
7

Effektivisering av ekologisk dagvattenhantering i stadsmiljö / Efficiency of ecological stormwater management in urban areas

Backström, Martin, Wikström, Ludvig January 2013 (has links)
I Jönköping har problemet med översvämningar, erosion och materialtransport varit ett stort problem i Strömsbergsbäcken i Jönköpings kommun. Detta har tillviss del orsakats av ett ökat dagvattenutsläpp i bäcken, vilket skapar kraftigaflödestoppar då den ursprungliga fåran inte är ”dimensionerad” för den ökadevattenmängden. Syftet med arbetet är att effektivisera ekologisk dagvattenhantering i stadsmiljö med högt dagvattenutsläpp. Målet med arbetet är i sin tur att framställa underlag för hur ekologisk dagvattenhantering i stadsmiljö kan genomföras och att rapporten skall kunna ge värdefull kunskap till liknande sammanhang. För attuppfylla målet har följande tre frågeställningar utformats som utgör en väsentligdel av arbetet: Hur kan belastningen på det allmänna dagvattennätet minskas? Hur kan föroreningsföljderna av dagvattenavrinning i stadsmiljö minskas? Vilka åtgärder är lämpliga för att effektivisera ekologisk dagvattenhantering i  Strömsbergsbäcken? Metoderna som använts för att besvara frågeställningarna är litteraturstudie, dokumentanalys och fallstudie. Resultaten visar på att vattenflödena från fyra av nio upptagningsområden som har sitt utlopp i Strömsbergsbäcken bör genomgå någon form av åtgärd som bromsar eller minskar dagvattenflödena innan det återgår till den naturliga vattencykeln. Dagvattenflödet kan minskas genom att anlägga åtgärder i området innan vattnet når vattendraget. Flödena kan också minskas genom åtgärder i anslutning tillbäcken, vid de utloppen där de största flödena förekommer. En väsentlig lösning för Strömsbergsbäcken är t.ex. att bygga om den befintliga branddammen, som ligger intill ett av utloppen, till en fördröjningsdamm för att bromsa en del av flödena i bäcken. / In the city of Jönköping problems with the irregular flow, erosions and transport of sediment materials are recurring in the brook Strömsbergsbäcken. The problems is somewhat caused by an increased flow of storm water in the brook, which leads to high flow peaks in some parts of the brook since the original furrow is not dimensioned for the increased amount of water. The purpose of this project work is to make ecological drainage management in urban environments with a high amount of storm water discharge more efficient. The objective with the report is to create valuable material of how to accomplish ecological drainage management in urban areas and that the report will be useful for future similar connections. To fulfill the objective, the following three questions have been designed as a significant part of the final project report: How can the load on the general drainage system be reduced? How can the pollution effects of storm water runoff in urban areas be reduced? Which treatments are appropriate to enhance the ecological storm water management in Strömsbergsbäcken ? The methods that have been used to solve these questions are document- and literature studies, and also a case study.The thesis results shows that the storm water flows from four of the nine areas that has its outlets in Strömsbergsbäcken, need to be treated through some kind of a solution or method that delays the water flow. The treatment could be performed in the area, before the storm water reaches the storm water network, which leads to Strömsbergsbäcken. The storm water flows can also be reduced by treatments adjacent to the outlets in the brook, where the largest flow peaks occurs. For example an essential solution to decrease the flows in Strömsbergsbäcken is to reconstruct the old dam located near one of the outlets into a basin, which will delay the stormwater flows.
8

Investigation Of Low Temperature Cracking In Asphalt Concrete Pavement

Qadir, Adnan 01 December 2010 (has links) (PDF)
In this study, low temperature cracking of asphalt concrete is investigated based on a laboratory experimental program including the design variables of aggregate type, gradation, asphalt content, binder grading, binder modification, and the experimental variables of cooling rate, and specimen size. The design of experiment is proposed according to the fractional factorial design principles to reduce the required number of test specimens. Mix designs are performed according to the Superpave mix design guidelines using materials obtained from the Turkish General Directorate of High-ways. In the course of this study, a test setup for thermal stress restrained specimen test for asphalt concrete is developed and used successfully to test a number of as-phalt concrete beam specimens. The same setup is also used for measuring the glass transition temperatures to obtain various thermo-volumetric properties of mixtures. Statistical methods are used to identify the effect of experimental variables on frac-ture strength, fracture temperature and other dependent variables obtained from the testing program. Statistical models are also developed to predict the fracture strength, fracture temperature and other thermo-volumetric properties of mixtures. Results of analyses show that aggregate type, binder modification, and asphalt content significantly affect both the fracture strength and fracture temperature of asphalt concrete. While the glass transition temperature is affected by only aggregate type, coefficients of contraction before and after the glass transition temperature are not influenced by any of the experimental variables. The results of this study provide an important basis to prevent low temperature cracking in asphalt concrete pavements.
9

Hotel Šafrán / Hotel Šafrán

Grman, Marek January 2020 (has links)
In the submitted project documentation is elaborated a design of a wellness hotel with a restaurant. The wellness hotel is situated in Rusava in the Zlin region. The built-up area of the hotel is 704.85 square meters. The new hotel is designed for short-term stays. There is a wellness (spa) area, restaurant, conference hall and a playroom in the hotel. There are three floors and the cellarage under the whole hotel. The building is located on a sloping land. The building is based on plain concrete strips. Vertical above-ground constructions are designed from the Porotherm system. The basement masonry is made of permanent shuttering kits/systems. Hotel’s ceilings are made of prefabricated Spiroll panels. The roof above the first floor is a single-layer paved flat roof. The roof above the third floor is designed as an impassable single-layer flat roof. This diploma thesis includes a study of the wellness hotel, layout drawings, architectural building scheme, fire safety scheme and building physics. Building visualizations are also part of this diploma thesis.
10

An investigation of detecting potholes with UAV LiDAR and UAV Photogrammetry

Hedenström, Linus, Eriksson, Sebastian January 2021 (has links)
Potholes are caused by erosion and as such always emerging on our roadnetwork. Potholes may not only cause great damages to vehicles, but can alsocause road accidents, which in the worst case are fatal. Today, the detection ofpotholes is usually based on citizen reports or ocular inspection by vehicle,where a loose description of the potholes properties and location can be given.Recent research has explored the possibility of aerial inspection of paved roadswith the new, cost effective, Structure-from-Motion (SfM) technique, whichcan produce 3D point clouds from photogrammetric data. SfM point cloudshave then been used in conjunction with processing algorithms toautomatically detect and extract potholes from paved surfaces. However, theresults have not been optimal for practical use. The purpose of this study is,therefore, to explore the possibility of using UAV LiDAR for potholedetection in paved roads as a better alternative to the currently popularStructure-from-Motion (SfM) technique. A LiDAR point cloud is derived by alaser scanner and may have several advantages over SfM, for instance, theinsensitivity to poor light conditions and modelling errors. This study is setout to answer how point clouds derived from UAV SfM and UAV LiDARcompare to each other regarding detecting potholes of different sizes, wheredetected potholes will be compared to ground truth data. An elevation check,consisting of 126 height control points along the paved road, will also be usedto evaluate the height accuracy in the clouds. Data collection is done with theUAV system mdLiDAR3000DL aaS containing a RIEGL miniVUX-1DLlaser scanner for LiDAR data and Sony RX1R II 42.4 megapixel camera forSfM data. The data for both methods are collected during the same flight. Theproposed method automatically detects and extracts potholes from a pavedsurface based on the vertical distance to local reference planes which representthe undamaged road surface. The point clouds are filtered in CloudComparebefore imported to TerraScan for detection and extraction of potholes. Theextraction results are then controlled by a set of terrestrial measurements bytotal station. The results show that potholes with a smaller width of at least16.5 cm and a depth of at least 2.7 cm can be detected and extracted frompoint clouds derived by UAV LiDAR at a flight altitude of 30 m. Theextracted potholes had a standard deviation of 1.40 cm in width and 6.7 mmin depth. Shadows on the road caused height anomalies in the point cloudproduced by Structure-from-Motion (SfM), which made pothole detectionimpossible with the proposed methodology. / Potthål skapas genom erosion i vägar och uppstår varje år i vägnätet. Skadornapåverkar inte bara fordonens skick, utan kan även vara orsaken till olyckorsom i vissa fall är dödliga. I dagsläget detekteras potthål genom ockulärt frånfordon av kommunala arbetare eller så rapporteras de in av medborgare via etjänst där en lös beskrivning kan ges angående potthålens egenskaper ochposition.På senare tid har studier utforskat möjligheterna för flygburen inspektion avasfalterade vägar med den nya, kostnadseffektiva, Structure-from-Motion(SfM) tekniken som kan producera 3D-punktmoln från fotogrammetrisk data.Punktmolnen som är framtagna genom denna metod har vidare använtstillsammans med bearbetningsalgoritmer för att detektion och extraktion avpotthål i asfalterade vägar. Dock har resultaten inte varit optimala för attmetoden ska fungera i praktiken. Syftet med den här studien är därför attutforska möjligheten för att använda UAV LiDAR som en bättre metod fördenna process. Punktmoln framtagna genom LiDAR-teknik, mer känt somlaserskanning, kan ha ett flertal potentiella fördelar över SfM som okänslighetmot modelleringsfel och dåliga ljusförhållanden.Denna studie ger svar på hur punktmoln framtagna genom UAV LiDAR ochUAV SfM förhåller sig till varandra när det gäller detektion av potthål i olikastorlekar från asfalterade vägar, där potthålens dimensioner kommer attjämföras mot markbundna kontrollmätningar. Vidare görs en höjdkontrollmot 126 höjdstöd i båda punktmolnen för att jämföra kvaliteten förhöjdmätningar på den asfalterade vägen genom respektive metod.Insamlingen av data gjordes samtidigt under samma flygning för bådametoderna. Drönaren som användes var Microdrones mdLiDAR3000DL aaSmed en RIEGL miniVUX-1DL laserskanner och en Sony RX1R II 42,4megapixelkamera monterad. Mjukvarorna som har använts för bearbetning ärCloudCompare för filtrering av brus med mera och TerraScan för självadetektions -och extraktionsprocessen.Resultatet visar att det är möjligt att extrahera potthål från LiDAR-baseradepunktmoln med en mindre bredd på minst 16,5 cm och ett djup på 2,7 cm.Standardavvikelsen för potthålens bredd är 1,4 cm och 6,7 mm i djup.Grupper av avvikande punkter skapades på vägen i det SfM-baseradepunktmolnen som en följd av ett modelleringsfel i skuggområden på vägen,vilket vidare gjorde detektion -och extraktionsprocessen omöjlig med denframtagna metoden.

Page generated in 0.0437 seconds