Repositório Colecção: CEC_VC_ARNCEC_VC_ARNhttps://hdl.handle.net/1822/11032024-03-28T21:52:02Z2024-03-28T21:52:02ZDesempenho de barreiras acústicas : dois métodos de avaliaçãoFreitas, Elisabete F.Trabulo, Luíshttps://hdl.handle.net/1822/84372019-07-08T15:46:55Z2008-12-05T18:25:49ZTítulo: Desempenho de barreiras acústicas : dois métodos de avaliação
Autor: Freitas, Elisabete F.; Trabulo, Luís
Resumo: Em Portugal tem-se verificado um crescimento exponencial da colocação de barreiras acústicas, como meio de resposta às exigências de qualidade ambiental definidas pela Comunidade Europeia. Este facto tem como consequência a necessidade de verificação do desempenho destes dispositivos, particularmente do isolamento sonoro aéreo. Assim, no presente artigo apresentam-se as orientações da Norma Europeia CEN/TS 1793-5:2003, relativa ao método de ensaio para determinar o isolamento sonoro aéreo dos dispositivos de redução do ruído, e uma metodologia expedita, que poderá ser usada como indicativa do desempenho destes dispositivos. Para as duas metodologias apresenta-se o princípio e procedimento de ensaio, o equipamento e a forma de avaliação do desempenho. Apresenta-se ainda a avaliação do desempenho de 3 barreiras acústicas, constituídas por materiais diferentes, feita através do método expedito. Finalmente, são feitas algumas considerações quanto aos métodos apresentados, prevendo-se que a metodologia preconizada na norma europeia seja de difícil execução in situ, especialmente em zonas de relevo acidentado. A avaliação do desempenho das barreiras acústicas com o recurso a estas metodologias, em diferentes fases do seu ciclo de vida, poderá constituir uma solução vantajosa e fiável.
<b>Tipo</b>: article2008-12-05T18:25:49ZModelling an asphalt pavement in PortugalIonescu, Andrei GabrielFreitas, Elisabete F.https://hdl.handle.net/1822/79632008-11-24T12:35:57Z2008-07-04T18:52:53ZTítulo: Modelling an asphalt pavement in Portugal
Autor: Ionescu, Andrei Gabriel; Freitas, Elisabete F.
Resumo: This article presents the modelling procedure of an existent pavement in Portugal,
carried out by the author in the frame of “Leonardo da Vinci” Student Mobility
Program, Contract RO/2004/PL93209/S, at Universidade do Minho - Center of
Civil Engineering.
The 6 years old pavement under study exhibited an important extent of cracking
and ravelling with high severity level, indicative of premature failure.
The assessment of the structural condition of the pavement requires the definition
of its model. The adopted model is based on multilayer elastic (MLE) theory as it is
one of most used models.
The establishment of the model comprised several tasks, such as: i) surface
condition assessment, based on visual inspection; ii) coring in and out of the wheel
path and over cracks; iii) deflection measurement by means of a falling weight
deflectometer; iv) definition of homogeneous subsections; v) back calculation of
the stiffness moduli using Bisar 3.0 Program; vi) temperature correction.
The back calculation of the stiffness modulus presented some difficulties as far as
curve fitting is concerned. This might have been a consequence of using simplified
models. Therefore, further research should focus this topic.
<b>Tipo</b>: article2008-07-04T18:52:53ZMethodology used in a recent highway construction in PortugalBotezatu, CostelSilva, Hugo Manuel Ribeiro Dias daOliveira, Joelhttps://hdl.handle.net/1822/79622008-11-24T12:35:54Z2008-07-04T18:44:50ZTítulo: Methodology used in a recent highway construction in Portugal
Autor: Botezatu, Costel; Silva, Hugo Manuel Ribeiro Dias da; Oliveira, Joel
Resumo: During the last years, Central and Eastern European countries aimed to increase the participation of the private sector in the construction of new highways and in the development of the transportation network. Presently, public funds are scarce to support the call for transportation infrastructures and the network development in the new EU countries, since projects and the construction of highways involve a high capital investment and an extremely long amortization. So, a possible solution for an adequate risk management of the public funds is the private-public partnerships (PPP), namely through the use of concessions (i.e. construction and exploitation of the public highways network by private entities). One of the European countries which is widely using the concession model in its Road National Strategic Plan is Portugal. This paper is based on the work carried out at the Department of Civil Engineering of the University of Minho, within the Highways group, in the frame of “Leonardo da Vinci” Student Mobility Program, Contract RO/2004/PL93209/S, and the main objective is to study the Portuguese experience on the use of the concession model, in order determinate its main advantages and disadvantages. A case study on the use of the concession model was followed for four months during the construction of some new stretches of highways located near Oporto city.
<b>Tipo</b>: article2008-07-04T18:44:50ZThe road network rehabilitation for the 21st century: a global vision on innovation in road rehabilitationPereira, Paulo A. A.Pais, Jorge C.Freitas, Elisabete F.Silva, Hugo Manuel Ribeiro Dias daOliveira, Joelhttps://hdl.handle.net/1822/79492019-04-04T11:50:00Z2008-07-03T19:37:25ZTítulo: The road network rehabilitation for the 21st century: a global vision on innovation in road rehabilitation
Autor: Pereira, Paulo A. A.; Pais, Jorge C.; Freitas, Elisabete F.; Silva, Hugo Manuel Ribeiro Dias da; Oliveira, Joel
Resumo: This article intends to be an approach to road network rehabilitation in the context
of the new challenges for the near future. Firstly, the current methodology used in
the maintenance and rehabilitation and its impact on the pavement life cycle costs
is presented. Secondly, the role of innovation at the service of society in the field of
road engineering is presented in order to assure a high level of the ride quality, as
well as a sustainable construction and rehabilitation of road pavements.
<b>Tipo</b>: article2008-07-03T19:37:25ZDefinition of homogenous road sectors according to COST 336Vrancianu, I.Freitas, Elisabete F.https://hdl.handle.net/1822/79472008-11-24T12:36:24Z2008-07-02T21:33:48ZTítulo: Definition of homogenous road sectors according to COST 336
Autor: Vrancianu, I.; Freitas, Elisabete F.
Resumo: The present paper presents the work undertaken by the author in the frame of “Leonardo da Vinci” Student Mobility Program, Contract RO/2004/PL93209/S, at Universidade do Minho - Center for Civil Engineering, in Portugal.
The work dealt with the structural assessment and design of the rehabilitation of a highway sector in northern Portugal. A brief description of the main activities performed and the main results of the work are presented. It included, surface and structural condition assessment, coring, laboratory testing, and estimation of residual life and overlay design.
A methodology to divide the road into homogenous sectors, according to recommendations of COST 336 Action Final Report, is applied in order to optimize the rehabilitation activities. The method is based on the computation of the cumulative sum of the deflection, on validation of the homogeneity and analysis of the statistical relevance of the division.
The methodology is easy to use and results, in this case, matched the field visual observations and the results of the laboratory tests. Furthermore, it could be easily integrated in a computer program.
<b>Tipo</b>: article2008-07-02T21:33:48Z