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Biblioteca Digital do IPB (53.442 recursos)

A Biblioteca Digital do IPB, tem por objectivo divulgar e permitir o livre acesso à produção científica produzida pela comunidade académica, promovendo a integração, partilha e a visibilidade da informação científica e garantindo a preservação da memória intelectual do Instituto Politécnico de Bragança.

DCCP - Comunicações a Conferências

Mostrando recursos 1 - 20 de 31

  1. Qualifications and professional competencies of the construction manager in Portugal: the impact of the Bologna process

    Abreu, Maria Isabel; Oliveira, Rui
    The legal framework concerning the construction industry is closely related with the industry’s specificities in each country. With the increasing globalisation of the economy, particularly in the European Union, there is a trend for a normalisation of the legal framework related to construction practices. In terms of professional practice in construction in Portugal, the graduate professionals are architects, civil engineers and technical civil engineers. In order to legally practise in the field, architects must be registered in the Order of Architects, civil engineers with the Order of Engineers and technical civil engineers with the Professional Association of Technical Engineers. The legal framework for the activity of...

  2. Influence of temperature variation on the reflective cracking behaviour of asphalt overlays

    Minhoto, Manuel; Pais, Jorge; Pereira, Paulo
    The objective of this paper is to present a study about the influence of temperature on the reflective cracking behavior through the evaluation of the overlay damage associated to the temperature variation during the year. The development of this study war based on the numerical simulation of the overlay behaviour, based on a three-dimensional finite-element analysis, considering the simultaneous loading of traffic and temperature variation and considering the most predominant type of overlay distress observed in the field: the reflective cracking. A mechanistic-based overlay design method was used to predict the reflective cracking overlay life. The occurrence of the temperature...

  3. Consideração das variações de temperatura no comportamento à reflexão de fendas dos reforços de pavimentos

    Minhoto, Manuel; Pereira, Paulo; Pais, Jorge
    O reforço de pavimentos constitui uma técnica de conservação estrutural na qual se baseiam as estratégias de conservação mais utilizadas na reabilitação dos pavimentos, visando a reposição da sua capacidade estrutural. Quando o reforço é aplicado sobre pavimentos fendilhados ocorre normalmente um mecanismo de ruína caracterizado pela propagação das fendas do pavimento existente para as camadas de reforço, designado por reflexão de fendas. No estudo que se apresenta, procedeu-se a uma avaliação, do efeito das variações de temperatura na ocorrência do mecanismo da reflexão de fendas, considerando a acção actuando isoladamente e actuando conjugada com o efeito da acção do...

  4. A model for pavement temperature prediction

    Minhoto, Manuel; Pais, Jorge; Pereira, Paulo
    A finite element model has been developed to calculate the temperature of a pavement located in the Northeast of Portugal. The goal of the case study presented in this paper is the validation of this model. Input data to the model are the hourly values for solar radiation and temperature, and mean daily values of wind speed obtained from a meteorological station. The thermal response of a multilayered pavement structure is modeled using a transient thermal analysis for four months time-period (December 2003 - April 2004) and the analysis was initiated with the full depth constant initial temperature obtained from field measurements. During these four months,...

  5. Reabilitação de edifícios. Está o meio técnico preparado para o desafio?

    Oliveira, Rui; Sousa, Hipólito; Lopes, Jorge
    A reabilitação de edifícios, parece estar a tornar-se uma área estratégica de construção em Portugal, não só pela progressiva consciência da necessidade de abrandar a realização de obra nova, como também pela necessidade de privilegiar a reabilitação do parque edificado existente. A presente tendência de actuação na requalificação dos edifícios antigos demonstra que é necessário alterarmetodologias de intervenção. Para tal é necessário constribuir como medidas de carácter legislativo, com efeito dinamizador do sector.

  6. Characterisation of the portuguese R&M construction market: a special focus on heritage buildings

    Oliveira, Rui; Sousa, Hipólito; Lopes, Jorge
    The rehabilitation of heritage buildings is an important aspect in the safeguard and upgrading of the local environment, and contributes to the diversification of suppy in the property market. However, the contribution of the R&M segment to the total construction markek in Portugal is almost insignificant when compared to the other countries of the European Union. This study is part of a wider research project that investigates the different technological aspects of intervention in heritage buildings and their contribution to the development of the local property market. The data and information used in this study stem from Euroconstruct Report, and...

  7. Technological aspects of portuguese masonry rehabilitation on heritage buildings

    Sousa, Hipólito; Oliveira, Rui
    The rehabilitation of building, specially heritage buildings, is an important aspect in the safeguard and upgrading of local environment. However, the contribution of this segment to the local construction market in Portugalis not significant when compared to the other countries of the European Union. A casestudy consisting of 57 heritage projects submitted to a government department responsible for the approval and listing of these buildings allows to identify the different technological aspects of intervention in heritage buildings, namely on masonry walls. The results presented in this papel shows taht the tecnologies used in heritage buildings are frequently similar to those...

  8. Análise de intervenções em edifícios de valor patrimonial da Região Norte

    Oliveira, Rui; Sousa, Hipólito
    A preservação e reabilitação de edifícios de valor patrimonial vai crescer em Portugal, sendo necessário conhecer as práticas nesta área. O estudo de cerca de 57 projectos recentes deste tipo de obra envidencia que é necessário desenvolver competências específicas e uma cultura de maior rigor ao nível do levantamento/diagnóstico, tipo de projecto e tecnologias adoptadas nestas intervenções conforme se evidencia nesta comunicação.

  9. Improving housing quality as a marketing strategy

    Fernandes, Sílvia; Teixeira, José M. Cardoso; Lopes, Jorge
    Prospective housing clients in Portugal face up a marked lack of information on the characteristics of housing products, which most often turn out to be very different to their expectations. This lack of information does not allow them to relate quality and cost adequately. Furthermore, housing products are not adequately differentiated owing to an inefficient approach to the market from the part of different actors in the property sector, which makes the understanding of the true needs and wishes of the client difficult. Nowadays, in a highly competitive housing market, it is increasingly necessary to weigh the quality of supply,...

  10. Asphalt pavement temperature prediction

    Minhoto, Manuel; Pais, Jorge; Pereira, Paulo
    A 3-D finite element model (FEM) was developed to calculate the lemperature of an asphtalt rubber pavement localed in the Northeast of Portugal. The goal of the case study presented in this paper is to show the good accuracy temperature prediction tha can be obtained with this model when compared with the field pavement thermal condition obtained during a year. lnput data to the model are the hourly values for solar radiation and temperature and the mean daily value of wind speed obtained from a meteorological station. The therminal response of a multilayered pavement structure is modelled using a FEM...

  11. Evaluation of the visco-elastic properties in asphalt rubber in conventional mixtures

    Minhoto, Manuel; Pereira, Paulo; Pais, Jorge
    Flexible pavements are subjected to a set of degradations on the pavement surface, such as cracks and other specific types of distress which arise from traffic and temperature variations and which are responsible for the users’ unsafety and discomfort. The occurrence of temperature variations in the pavement leads to a severe aggravation of the reflective cracking phenomenon what implies a premature distress of the overlays. In this way, a theoretical study about the influence of temperature variation in the reflective cracking overlay behaviour was performed. To this end, a thermo-mechanical characterization of bituminous materials was made through a set of...

  12. Reabilitação de zonas de ponte térmica da envolvente dos edifícios

    Abreu, Maria Isabel; Corvacho, Helena
    São bem conhecidas as implicações negativas da existência de pontes térmicas na envolvente dos edifícios, tais como a ocorrência de condensações superficiais e o desenvolvimento de bolores. Com a intenção de evitar essas implicações negativas, tem vindo a ser concebidas correcções, que introduzem uma muito reduzida ou nula melhoria do seu comportamento térmico e que, com frequência, dão origem novas anomalias construtivas. Com o objectivo de propor soluções que contribuam, simultaneamente, para minimizar o fenómeno de ponte térmica e resolvem eventuais anomalias de outra natureza, foi levado a cabo na FEUP um estudo do qual se apresentam aqui alguns resultados....

  13. Reflective cracking behavior for traffic and temperature effects

    Minhoto, Manuel; Pais, Jorge; Pereira, Paulo
    This paper presents a study on the influence of the effects of temperature variations, in comparison with traffic effects, on the reflective cracking overlay behavior. It is intended to contribute to the improvement of the pavement overlay design methods which consider reflective cracking as one among distress criteria. The development of this study was based on the numerical simulation of the overlay behavior, through the implementation of numerical thermal and mechanical models based on the finite element, considering the simultaneous action of traffic and temperature variations and their influence on reflective cracking.

  14. Laboratory performance of asphalt rubber mixtures

    Fontes, Liseane; Trichês, Glicério; Pais, Jorge; Pereira, Paulo; Minhoto, Manuel
    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: tire rubber modified asphalt binder (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtures produced with different asphalt rubber binders, using gap and dense gradations. The mechanical behaviour of the mixtures studied was established through several laboratory tests (stiffness, fatigue and...

  15. The traffic and temperature effect on the reflective cracking

    Minhoto, Manuel; Pais, Jorge; Pereira, Paulo
    This paper presents a study on the influence of the effects of temperature variations, in comparison to the traffic effects, on the reflective cracking behavior. It intends to contribute to the improvement of the pavement overlay design methods which consider reflective cracking as one among distress criteria. The development of this study was based on the numerical simulation of the overlay behavior, through the implementation of numerical thermal and mechanical models based on the finite element, considering the simultaneous action of traffic and temperature variations and their influence on reflective cracking. For overlay design purposes, it is important to consider...

  16. Recycling of Asphalt Pavements with Asphalt Rubber

    Pais, Jorge; Pereira, Paulo; Minhoto, Manuel; Baptista, António
    Pavement recycling has been an important rehabilitation technique to deal with reclaimed materials from old pavements which are usually sent to landfills. The application of this technique contributes to: i) the accomplishment of the requirements defined by the European legislation for the amount of material sent to landfills; ii) the reduction in the use of new raw materials used to produce pavement layers. The reduction of materials to be used in pavement rehabilitation has also been possible through the use of asphalt rubber binder (i.e. asphalt modified by crumb rubber from ground tyres) in the production of asphalt mixtures. These...

  17. Analysis of the variation in the stiffness modulus through four point bending tests

    Pais, Jorge; Pereira, Paulo; Minhoto, Manuel; Fontes, Liseane; Kumar, D.S.N.V.A.; Silva, B.T.A.
    Pavement layers are characterized by basic material properties, among which the stiffness modulus and the Poisson ratio assume a preponderant importance in linear elastic analysis. The stiffness modulus is usually assessed through samples extracted from a pavement or prepared in laboratory. The number of specimens used to calculate the stiffness modulus of na asphalt mixture plays an important role in the precision of pavement design. Thus, this paper presents a study to evaluate the number of tests to assess the stiffness modulus of asphalt mixtures through the four-point bending technique. The results obtained from five different asphalt mixtures were used...

  18. Analysis of the variation in the fatigue life through four-point bending tests

    Pais, Jorge; Pereira, Paulo; Minhoto, Manuel; Fontes, Liseane; Kumar, D.S.N.V.A.; Silva, B.T.A.
    The fatigue resistance of asphalt mixtures is calculated through laboratory tests which require some time depending on the strain level applied to the specimen. For very low strain levels, identical to the one installed in the pavement of this study, one test may last more than one week depending on the testing frequency. The time needed for the development of the fatigue law may last longer. The number of specimens used to calculate the fatigue resistance of an asphalt mixture plays an important role in the precision of pavement design. Thus, this paper presents a study to evaluate the number...

  19. Evaluation of fatigue performance at different temperatures

    Minhoto, Manuel; Pais, Jorge; Pereira, Paulo
    The fatigue performance of asphalt mixtures is used to predict pavement life to control the cracking in the asphalt layers. The design of an asphalt pavement is usually made for a specific temperature, what is intended to represent the pavement behaviour throughout a whole year. For damage analysis during a year, along which the pavement temperature constantly varies, it is necessary to calculate the fatigue performance of pavements at a wide range of temperatures. Thus, this paper presents the evaluation of the fatigue response of two asphalt mixtures, a conventional and an asphalt rubber mixture. Frequency sweep tests were also...

  20. Application of plateau value to predict fatigue life

    Pais, Jorge; Pereira, Paulo; Minhoto, Manuel; Fontes, Liseane; Kumar, D.S.N.V.A.; Silva, B.T.A.
    Fatigue resistance of asphalt mixtures represents an important parameter for pavement design. This fatigue resistance is calculated through laboratory tests which require some time depending on the strain level applied to the specimen. For very low strain levels, identical to the one installed in the pavement, one test may last more than one week depending on the testing frequency. The time needed for the development of the fatigue law may last longer. Recent developments introduced an energy approach, based on the ratio of dissipated energy change, which leads to a plateau value that requires short testing to predict the specimen...

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