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  • 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.
11

Avaliação de normas de identificação de defeitos para fins de gerência de pavimentos flexíveis / Evaluation of pavement distress identification standards for flexible pavement management

Denise Maria Camargo Machado 26 August 2013 (has links)
Este trabalho analisa métodos de avaliação da condição de pavimentos asfálticos flexíveis, abordando os vários tipos de defeitos que podem surgir nos mesmos, suas causas e atividades de manutenção e reabilitação mais indicadas, em função da severidade e extensão com que se manifestam. Está inserido dentro do tema Gerência de Pavimentos, sendo de grande importância o conhecimento das condições dos pavimentos para a tomada de decisão quanto aos investimentos necessários para garantir o tráfego de veículos com segurança, conforto e, principalmente, economia, ou seja, com baixos custos de operação dos veículos. A avaliação dos pavimentos permite a identificação de falhas construtivas, que se manifestam precocemente, bem como acompanha o desgaste natural que sofrem todos os pavimentos, contribuindo para que as inevitáveis intervenções sejam bem selecionadas e executadas nos momentos adequados, possibilitando, assim, a melhor utilização possível dos recursos disponíveis. Neste trabalho são estudados métodos de avaliação de pavimentos utilizados no Brasil, nos Estados Unidos e na França, tanto para a gerência de pavimentos em nível de rede como em nível de projeto, para pavimentos rodoviários, urbanos e de aeroportos, com base em avaliações objetivas e subjetivas, considerando-se defeitos estruturais e não estruturais. Procurou-se fazer uma análise crítica com o intuito de contribuir para que se tenha, no Brasil, um método simples e eficiente para avaliação da condição dos pavimentos, desenvolvido com rigor acadêmico, mas de fácil utilização pelo meio técnico. Foram identificados os pontos negativos dos métodos utilizados atualmente no Brasil, buscando-se, nas normas internacionais, alternativas para a solução dos problemas existentes. Por fim, recomenda-se a revisão da Norma Brasileira, com alterações para que sua aplicação possa ser efetuada de maneira homogênea pelos diferentes técnicos que a utilizam, tornando-a mais ágil, simples e eficiente. As alterações propostas incluem: definição mais clara das Trincas, agrupamento dos defeitos Corrugação e Escorregamento, separação entre defeitos de origem estrutural e não estrutural, aplicação mais efetiva de níveis de severidade, e avaliação do pavimento com a utilização do conceito de ICP. / This study examines methods for assessing the condition of flexible pavements, addressing the various types of pavement distress, their causes and rehabilitation and maintenance activities as a function of the severity and extension of the distresses. It is housed within the theme Pavement Management, which is of great importance to the decision regarding investments necessary to ensure the traffic of vehicles with safety, comfort and, above all, economy, i.e., low vehicle operation costs. The evaluation of pavements allows the identification of construction faults, which occurs suddenly, and it also records the natural pavement wear, contributing to well selected and executed at appropriate times interventions, thus enabling a better utilization of available resources. This work analyses methods for pavement evaluation used in Brazil, in the United States and in France, for pavement management at network and project level, for road, urban and airport pavements, based on objective and subjective evaluations, considering structural and non-structural distresses. It was tried to make a critical analysis with the aim to contribute to a simple and more efficient method to evaluate pavement condition, developed with academic rigor, but easy to be used by technical personnel. The identified weaknesses in methods currently used in Brazil can be minimized by the implementation of concepts already present in international standards. Finally, it is recommended the revision of the Brazilian standard, in order to be performed in a homogeneous way by different technicians who use it, making it more agile, efficient and simple. The proposed changes include: clearer definition of Cracking, clustering of two distresses in Shoving, separation of structural and non-structural distresses, more effective application of levels of severity and extent of distress, evaluation of pavement using the PCI concept.
12

AnÃlise da EvoluÃÃo de Defeitos de SuperfÃcie em Trechos da Malha RodoviÃria do Estado do Cearà / ANALISYS OF THE SURFACE DISTRESSES IN ROADS OF THE ROADWAY NETWORK OF THE STATE OF CEARÃ

Carlos Andre Melo Pontes 31 January 2012 (has links)
Devido à grande predominÃncia do modal de transporte rodoviÃrio no Brasil, se faz cada vez mais necessÃrio um controle sobre as aÃÃes de manutenÃÃo e de conservaÃÃo das rodovias. Para isso, muitos ÃrgÃos rodoviÃrios adotam modernos sistemas informatizados, que à o caso do DER/CE, que utiliza o SIGMA (Sistema Integrado de GestÃo da ManutenÃÃo). O sistema, atravÃs do subsistema SGP (Sistema de GerÃncia de Pavimentos), possui um vasto banco de dados relativos à condiÃÃo das rodovias, que à alimentado com dados provenientes de levantamentos de campo, que trazem, periodicamente, informaÃÃes atualizadas da condiÃÃo das rodovias estaduais. Estes dados sÃo adquiridos utilizando metodologias definidas pela equipe tÃcnica do DER/CE, baseadas em procedimentos normalizados, sendo os principais: o levantamento de irregularidade longitudinal (IRI) e o Levantamento Visual ContÃnuo (LVC). O primeiro avalia o conforto ao rolamento e o segundo registra os defeitos de superfÃcie das rodovias. Esta pesquisa apresenta uma anÃlise comparativa entre dados de LVC e de IRI, avaliando a evoluÃÃo das quantidades de defeitos e do IRI e as metodologias e os equipamentos envolvidos nos levantamentos. Apresenta, ainda, uma tentativa de compreensÃo da evoluÃÃo dos parÃmetros medidos pelo LVC ao longo de oito anos. Espera-se que, com a contribuiÃÃo desta pesquisa, as metodologias e os dados relativos à condiÃÃo das rodovias sejam analisados considerando as limitaÃÃes encontradas e que sejam sempre adotados o equipamento e o procedimento mais apropriados. / Due to the large predominance of the transportation by highways in Brazil, it is necessary to control the actions related to maintenance and conservation of the roads. With this purpose, institutions make use of modern computational systems, such as the DER/CE, which uses the ISMA (Integrated System of Maintenance Administration). The referred system, using the subsystem PMS (Pavement Management System), has a large database related to the roads condition, filled with data provided by surveys that bring periodically up to date information of the state roads. These data are acquired by using methodologies defined by the technical staff of the DER/CE, based on the following normalized procedures: Visual Continuous Survey (LVC) and International Roughness Index Survey (IRI). The first one evaluates the comfort of the traffic rolling and the second registers the surface distresses of the roads. This research presents a comparative analysis between LVC and IRI data, evaluating the evolution of the distresses and the methodologies and equipments involved in the procedures. It is expected that, with the contribution of this research, the methodologies and road related data be analyzed considering the limitations of the equipments and procedures.
13

Aquisição de dados sobre a condição dos pavimentos visando a implementação de sistemas de gerência de pavimentos urbanos / Acquisition of data on the condition of the pavement aiming at the implementation of systems of management of urban pavement

Fábio Zanchetta 06 January 2005 (has links)
Este trabalho apresenta um estudo de caso, realizado na cidade de São Carlos-SP (cidade brasileira de médio porte), que analisa o processo de implantação de um Sistema de Gerência de Pavimentos Urbanos (SGPU). Os objetivos são determinar a melhor maneiro de coletar dados em campo, fornecer subsídios para a implantação de sistemas de gerência em outras localidades, analisar a reprodutibilidade e a repetibilidade das avaliações realizadas com a sistemática proposta pelo método SHRP (1993) e, por fim, comparar esse método com o adotado em Porto Alegre-RS, que se baseia na norma DNER ES 128/83. Os resultados apontaram o caminhamento como melhor forma de avaliar pavimentos urbanos. Os parâmetros analisados para verificar a reprodutibilidade e a repetibilidade das avaliações dos pavimentos mostraram altas correlações e baixas dispersões. O método SHRP mostrou-se mais completo do que a sistemática de avaliação baseada em norma do DNER. / This work presents a case study developed in São Carlos-SP (a Brazilian medium sized city), that analyses the process of implementation of an Urban Pavement Management System (UPMS). Its objectives are the determination of the best way to collect field data, to subsidy the implementation of a management system in other medium sized cities, to analyse the reproducibility and the repeatability of the evaluations accomplished with the systematic proposed by the SHRP method (1993), and finally, to compare the SHRP method with a field survey method used in Porto Alegre-RS, which is based on the DNER Standard ES 128/83. The results pointed to the walking as better form of evaluating the urban pavement. The parameters used to verify the reproducibility and the repeatability of pavement evaluation showed high correlations and low dispersions. The SHRP method was better than the evaluation based on the DNER standard.
14

Índice de condição do pavimento (ICP) para aplicação em sistemas de gerência de pavimentos urbanos / Pavement condition index (PCI) for application in urban pavement management systems

Edgar Misael Arévalo Páez 27 April 2015 (has links)
O Índice de Condição do Pavimento (ICP), também apresentado como um índice de defeitos combinados, é, em muitos Sistemas de Gerência de Pavimentos Urbanos (SGPU), o único indicador da qualidade do pavimento dos segmentos que compõem a malha viária. Este trabalho é baseado em conceitos gerais, utilizando os tipos de defeito de pavimentos flexíveis do Programa SHRP (Strategic Highway Research Program), bem como a forma de quantificação da severidade e extensão com que se manifestam na superfície dos pavimentos, mas propõe um novo método para determinação de um Índice de Condição de Pavimentos Urbanos (ICPU), que considera as condições particulares de projeto, materiais, técnicas construtivas, controle de qualidade e políticas de manutenção e reabilitação da cidade em que está sendo implantado. O cálculo do ICPU é desenvolvido em três etapas, em que primeira calcula o peso por tipo de defeito, a partir de questionários preenchidos por profissionais da área de infraestrutura de transportes. A segunda etapa define fatores de ponderação para os pesos, por tipo de defeito e em função da severidade. A terceira e última etapa do método consiste na análise de correlação entre segmentos representativos da malha viária urbana em análise, o que, no estudo de caso desenvolvido neste trabalho, utilizou 10.402 de um total de 111.497 segmentos do Distrito Federal do Brasil, distribuídos entre as trinta regiões administrativas, incluindo Brasília, que foram avaliadas, subjetiva e objetivamente, nos anos de 2010 a 2012, pela Companhia Urbanizadora da Nova Capital do Brasil (NOVACAP), e que permite a determinação dos fatores de ponderação em função da extensão, por tipo de defeito. / The Pavement Condition Index (PCI), also presented as an index of combined defects, is, in many Urban Pavement Management Systems (UPMS), the only indicator of pavement condition for the segments of the urban roadway network. This work is based on general concepts, using the flexible pavement distress types of the SHRP Program (Strategic Highway Research Program), as well as the way to evaluate the severity and extent to which they manifest on the pavement surface, but proposing a new method for determining an Urban Pavement Condition Index (UPCI), which considers the particular conditions of design, materials, construction techniques, quality control and policies of maintenance rehabilitation of the city in which it is being implemented. The calculation of the UPCI is developed in three stages, in which the first calculates the weight by defect type, from questionnaires completed by professionals in the transport infrastructure area. The second stage sets weighting factors for the weights by distress type depending on the severity. The third and final step of the method consists in the analysis of correlation between representative segments of the urban roadway network in question, which, in the case study developed in this study, used a total of 10,402 among 111,497 segments of the Federal District of Brazil, distributed among the thirty administrative regions, including Brasilia, which were evaluated subjectively and objectively, in the years 2010-2012, by the Urbanization Company of the New Capital of Brazil (NOVACAP), which allows the determination of the weighting factors depending on of the distress type as a function of the extension.
15

Using Mixture Design Data and Existing Prediction Models to Evaluate the Potential Performance of Asphalt Pavements

January 2020 (has links)
abstract: Several ways exist to improve pavement performance over time. One suggestion is to tailor the asphalt pavement mix design according to certain specified specifications, set up by each state agency. Another option suggests the addition of modifiers that are known to improve pavement performance, such as crumb rubber and fibers. Nowadays, improving asphalt pavement structures to meet specific climate conditions is a must. In addition, time and cost are two crucial settings and are very important to consider; these factors sometimes play a huge role in modifying the asphalt mix design needed to be set into place, and therefore alter the desired pavement performance over the expected life span of the structure. In recent studies, some methods refer to predicting pavement performance based on the asphalt mixtures volumetric properties. In this research, an effort was undertaken to gather and collect most recent asphalt mixtures’ design data and compare it to historical data such as those available in the Long-Term Pavement Performance (LTPP), maintained by the Federal Highway Administration (FHWA). The new asphalt mixture design data was collected from 25 states within the United States and separated according to the four suggested climatic regions. The previously designed asphalt mixture designs in the 1960’s present in the LTPP Database implemented for the test sections were compared with the recently designed pavement mixtures gathered, and pavement performance was assessed using predictive models. Three predictive models were studied in this research. The models were related to three major asphalt pavement distresses: Rutting, Fatigue Cracking and Thermal Cracking. Once the performance of the asphalt mixtures was assessed, four ranking criteria were developed to support the assessment of the mix designs quality at hand; namely, Low, Satisfactory, Good or Excellent. The evaluation results were reasonable and deemed acceptable. Out of the 48 asphalt mixtures design evaluated, the majority were between Satisfactory and Good. The evaluation methodology and criteria developed are helpful tools in determining the quality of asphalt mixtures produced by the different agencies. They provide a quick insight on the needed improvement/modification against the potential development of distress during the lifespan of the pavement structure. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2020
16

Verification of Mechanistic-Empirical Pavement Deterioration Models Based on Field Evaluation of In-Service Pavements

Gramajo, Carlos Rafael 15 July 2005 (has links)
This thesis focused on using a detailed structural evaluation of seven (three flexible and four composite) high performance in-service pavements designated as high-priority routes to verify the applicability of the Mechanistic Empirical (M-E) models to high performance pavements in the Commonwealth of Virginia. The structural evaluation included: determination of layer thicknesses (from cores, GPR and historical data), pavement condition assessment based on visual survey, estimation of layer moduli from FWD analysis as well as material characterization. One of the main objectives of this study was to utilize the results from the backcalculated moduli in order to predict the performance of this group of pavement structures using the M-E Design Guide Software. This allowed a quick verification of the performance prediction models used by comparing their outcome with the current condition. The in-depth structural evaluation of the three flexible and four composite pavements showed that all the sites are structurally sound. The investigation also confirmed that the use of GPR to determine layer thicknesses and the comparison with a minimum number of cores is a helpful tool for pavement structural evaluation. Despite some difficulties performing the backcalculation analysis for complex structures, the obtained results were considered reasonable and were useful in estimating the current structural adequacy of the evaluated structures. The comparison of the measured distresses with those predicted by the M-E Design Guide software showed poor agreement. In general, the predicted distresses were higher than the distresses actually measured. However, there was not enough evidence to determine whether this is due to errors in the prediction models or software, or because of the use of defaults material properties, specially for the AC layers. It must be noted that although an in-depth field evaluation was performed, only Level 3 data was available for many of the input parameters. The results suggest that significant calibration and validation will be required before implementation of the M-E Design Guide. / Master of Science
17

A Pavement Structural Capacity Index for Use in Network-level Evaluation of Asphalt Pavements

Bryce, James Matthew 05 April 2012 (has links)
The objective of this research was to develop a structural index for use in network-level pavement evaluation, which facilitates the inclusion of the pavements structural condition in many pavement management applications. The primary goal of network-level pavement management is to maintain an acceptable condition of the pavements within the network using available, and often limited, resources. Pavement condition is described in terms of functional and structural condition, and the current widespread practice is to only consider the functional condition during network-level evaluation. This practice results in treatments that are often under-designed or over-designed when considered in more detail at the project-level. The disagreement may be reduced by considering the structural capacity of the pavements as part of the network-level decision process. This research was conducted by identifying various structural indices, choosing an appropriate index, and then applying data from the state of Virginia to modify the index and show example application for the index. It was concluded that the Modified Structural Index best met the research objectives. Project-level and network level data were used to conduct a sensitivity analysis on the index, and example applications were presented. The results indicated that the inclusion of the Modified Structural Index into the network-level decision process minimized the errors between network-level and project-level decisions, when compared to the current network-level decision making process. Furthermore, the Modified Structural Index could be used in various pavement management applications, such as network-level structural screening, and developing structural performance measures. / Master of Science
18

Field performance of geogrid reinforced low-volume pavements

Joshi, Rutuparna Vidyadhar 05 November 2010 (has links)
For the past three decades, geosynthetics have been recognized as materials that can significantly improve the performance of pavements on weak subgrade. Pavements exhibit non-linear elasto-plastic behavior. The addition of geosynthetics is undoubtedly beneficial. This being said, researchers have concentrated more on lower life cycle cost and high benefit-cost ratio whereas much less attention has been given to the complex behavior of the reinforced pavement system. Comprehension of the short-term and long-term field performance of reinforced pavements under continued traffic and cyclic environmental loading has remained unexplored. There is empirical evidence indicating quantitative benefits of reinforced versus unreinforced pavement structure. However, quantification of the relative benefits of different types of reinforcement like geogrids and geotextiles lacks information. Further, evaluation of the benefits and comparison of chemical stabilization in the form of lime treatment with mechanical stabilization in the form of reinforcement for pavements on soft soils has received lack of attention. In view of this, full-scale instrumented reinforced and lime treated pavement sections with different schemes were studied. Regular Falling Weight Deflectometer (FWD) testing was conducted in a Farm-to-Market Road, in Grimes County, Texas. Three different geosynthetic products were used for base reinforcement and lime treatment was used for subbase stabilization. Deflection measurements for 9 field trips in 3.5 years were evaluated. Modified deflection basin parameters (DBPs) were defined to typically identify layer properties and were used to measure the relative damage to the base, subbase and subgrade for different sections. A modified Base Damage Index (BDI) and a modified Base Curvature Index (BCI) were defined as a part of this study to capture the benefit of reinforced base and lime stabilized subbase respectively. The variation in the DBPs over three periods of wetting and drying along with explanation of the observed trends forms a part of this research. In addition, a number of condition surveys were performed, during 3 years, to visually identify distresses in various sections. A unique distress quantification technique was developed for measuring deterioration of the pavement sections in terms of the observed distresses and FWD measurements. With this, an index of pavement performance was developed. Thus, the FWD deflection data analyses complemented by visual observation, reveals important information on performance of different geosynthetics with the same base course. Analysis of the field performance of the multiple experimental sections throws light on the relative merits of base reinforcement against lime stabilization. / text
19

Validação de resultados do inventário funcional de pavimentos flexíveis com o emprego do equipamento pavement scanner. / Validation of results of the functional inventory of flexible pavements with the use of pavement scanner equipment.

Fialho, Paloma Cruz Gentil 27 April 2015 (has links)
A elaboração de um programa de gerenciamento de uma rede rodoviária implica na utilização de montantes consideráveis de recursos em sua recuperação e manutenção. Neste cenário, ressalta-se a importância da validação de uma nova tecnologia de avaliação funcional de pavimentos para aplicação em rodovias brasileiras que permita a coleta de informações de forma automática, sem a interferência do profissional, minimizando o tempo de coleta e processamento de dados, reduzindo-se as interferências com o tráfego e garantindo informações de qualidade e de rápida restituição. O presente trabalho tem como objetivo a contribuição para o processo de avaliação funcional de pavimentos através validação de resultados do inventário funcional de pavimentos flexíveis com o emprego do equipamento Pavement Scanner, o que pode ser um novo processo que garanta a integridade, a confiabilidade e a plena restituição das informações para o projeto e programa de gestão de pavimentos. Para tanto, seções-teste foram inventariadas e estudadas, onde avaliou-se as condições funcionais do pavimento de acordo com a metodologia tradicional de avaliação da superfície do pavimento e sob a utilização do equipamento Pavement Scanner. Os resultados obtidos pelos diferentes métodos foram analisados e comparados, buscando-se determinar a variação obtida pelas diferentes técnicas de avaliação do pavimento, além da análise da repetitividade e reprodutividade de cada uma destas técnicas. Adicionalmente, foi estudada a aplicabilidade dos resultados obtidos pelo Pavement Scanner no cálculo do PCI (Índice da Condição do Pavimento, do inglês Pavement Condition Index), que é muito utilizado no exterior e considerado uma ferramenta eficaz na gerência de pavimentos. / The development of a road network management program implies the use of significant amounts of resources in their recovery and maintenance. In this scenario, it emphasizes the importance of validating a new technology of functional Pavement assessment for use in Brazilian highways that allows the automatic collection of information, without the interference of a professional, minimizing the time in collecting and processing of data, reducing interference with traffic and ensuring information quality and fast refund. This study aims to contribute to the process of functional pavement evaluation through the validation of results of the functional inventory of flexible pavements with the use of Pavement Scanner equipment, which can be a new process to ensure the integrity, reliability and full refund of information for the pavement management program. With this purpose, sections-tests were surveyed and studied, in which the functional pavement conditions were evaluated according to the traditional method of pavement surface evaluation and with the use of Pavement Scanner equipment. The results obtained by different methods were analyzed and compared, in order to determine the variation obtained by the different pavement evaluation techniques, in addition to the analysis of repeatability and reproducibility of each of these techniques. Furthermore, it was studied the applicability of the results obtained by Pavement Scanner in the calculation of PCI (Pavement Condition Index), which is widely used abroad and considered an effective tool in pavement management.
20

Validação de resultados do inventário funcional de pavimentos flexíveis com o emprego do equipamento pavement scanner. / Validation of results of the functional inventory of flexible pavements with the use of pavement scanner equipment.

Paloma Cruz Gentil Fialho 27 April 2015 (has links)
A elaboração de um programa de gerenciamento de uma rede rodoviária implica na utilização de montantes consideráveis de recursos em sua recuperação e manutenção. Neste cenário, ressalta-se a importância da validação de uma nova tecnologia de avaliação funcional de pavimentos para aplicação em rodovias brasileiras que permita a coleta de informações de forma automática, sem a interferência do profissional, minimizando o tempo de coleta e processamento de dados, reduzindo-se as interferências com o tráfego e garantindo informações de qualidade e de rápida restituição. O presente trabalho tem como objetivo a contribuição para o processo de avaliação funcional de pavimentos através validação de resultados do inventário funcional de pavimentos flexíveis com o emprego do equipamento Pavement Scanner, o que pode ser um novo processo que garanta a integridade, a confiabilidade e a plena restituição das informações para o projeto e programa de gestão de pavimentos. Para tanto, seções-teste foram inventariadas e estudadas, onde avaliou-se as condições funcionais do pavimento de acordo com a metodologia tradicional de avaliação da superfície do pavimento e sob a utilização do equipamento Pavement Scanner. Os resultados obtidos pelos diferentes métodos foram analisados e comparados, buscando-se determinar a variação obtida pelas diferentes técnicas de avaliação do pavimento, além da análise da repetitividade e reprodutividade de cada uma destas técnicas. Adicionalmente, foi estudada a aplicabilidade dos resultados obtidos pelo Pavement Scanner no cálculo do PCI (Índice da Condição do Pavimento, do inglês Pavement Condition Index), que é muito utilizado no exterior e considerado uma ferramenta eficaz na gerência de pavimentos. / The development of a road network management program implies the use of significant amounts of resources in their recovery and maintenance. In this scenario, it emphasizes the importance of validating a new technology of functional Pavement assessment for use in Brazilian highways that allows the automatic collection of information, without the interference of a professional, minimizing the time in collecting and processing of data, reducing interference with traffic and ensuring information quality and fast refund. This study aims to contribute to the process of functional pavement evaluation through the validation of results of the functional inventory of flexible pavements with the use of Pavement Scanner equipment, which can be a new process to ensure the integrity, reliability and full refund of information for the pavement management program. With this purpose, sections-tests were surveyed and studied, in which the functional pavement conditions were evaluated according to the traditional method of pavement surface evaluation and with the use of Pavement Scanner equipment. The results obtained by different methods were analyzed and compared, in order to determine the variation obtained by the different pavement evaluation techniques, in addition to the analysis of repeatability and reproducibility of each of these techniques. Furthermore, it was studied the applicability of the results obtained by Pavement Scanner in the calculation of PCI (Pavement Condition Index), which is widely used abroad and considered an effective tool in pavement management.

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