Artigos de Revista
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Estimativa do dano no manto resistente de quebra-mares de taludes, baseada no volume erodido. O caso do quebra-mar de Ponta Delgada
Na sequência dos estragos causados pelo furacão Lorenzo no molhe principal do porto de Ponta Delgada, foi elaborado um projeto de reparação do mesmo, tendo havido necessidade derealização de ensaios em modelo físico tridimensional com o objetivo de avaliar a estabilidade da solução projetada.
Ano: 2022
Autor(es): Lemos, R.; Fortes, C. J. E. M.; Silva, L. G.; Pinheiro, L.; Luis, L.
Editor: PIANC
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Estimativa do dano no manto resistente de quebra-mares de taludes, baseada no volume erodido. O caso do quebra-mar de Ponta Delgada
Em 2 de outubro de 2019, o furacão Lorenzo atingiu as ilhas do Arquipélago dos Açores, provocando estragos nas infraestruturas portuárias, nomeadamente no molhe principal do porto de Ponta Delgada. No sentido de minorar este problema, foi elaborado um projeto de reparação do molhe (CONSULMAR, 2020), tendo nesse âmbito sido necessária a realização dos ensaios em modelo físico tridimensional com o objetivo de avaliar a estabilidade da solução projetada.Os ensaios foram realizados num tanque de ondas irregulares do LNEC à escala geométrica1:65 e contemplaram 6 séries de ensaios associados a 3 rumos de agitação marítima (WSW, S, SSW) e a dois níveis de maré (baixa-mar e preia-mar) associados a períodos de pico (Tp) entre 12 s e 20 s e alturas de onda significativa (Hs) variando entre 8 m e 15 m, Lemos et al. 2020.
Ano: 2022
Autor(es): Lemos, R.; Fortes, C. J. E. M.; Silva, L. G.; Pinheiro, L.; Luis, L.; Mendonça, F.
Editor: PIANC
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Evaluating environmental effects on the structural behavior of the railroad track subgrade considering different sub-ballast design solutions
The subgrade of a freight railroad track must have sufficient bearing capacity to prevent excessive plastic strains and geometry-related problems to ensure its good performance. The track sub-ballast layer is used to distribute the loads from the ballast to the subgrade, as well as to mitigate climate-based subgrade problems. This study aims to evaluate the effects of Brazilian southeastern tropical climate on subgrade hydraulic and structural behavior, as well as its effect on the railroad track substructure. This is achieved by considering both granular and bituminous sub-ballast solutions. Accordingly, suction sensors were installed at the subgrade for the realtime monitoring and calibration of both track sections. The subgrade water retention was characterized by considering the effect of hydraulic hysteresis. Two independent finite element method (FEM) numerical models were developed. Water flow analyses were performed using a 2-D model to obtain the suction variation in the track substructure profile using climate-track interaction simulations. A 3-D model was used to evaluate the railroad track structural behavior in terms of wheel load
Ano: 2022
Número Páginas:
100761.
Autor(es): Castro, G.; Pires, J.; Motta, R.; Bernucci, L.; Fortunato, E.; Futai, M.
Revista: Transportation Geotechnics
Editor: Elsevier
Volume:
34.
Keywords: Suction; Unsaturated soil; Finite Element Method; Climatic action; Moisture content; Railroad Sub-ballast
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Evaluation of the Effect of a Combined Chemical and Thermal Modification of Wood though the Use of Bicine and Tricine
The effects of thermal modification of wood have been well established, particularly interms of reductions in mechanical performance. In recent years, there has been an increase in studies related to the Maillard reaction. More commonly associated with food chemistry, it involves the reaction of amines and reducing sugars during cooking procedures. This study has attempted to combine the use of amines and thermal modification, with subsequent properties investigated for the treatment of spruce (Picea abies (L.) H. Karst) and beech (Fagus sylvatica L.). In this initial study, the combined effects of chemical treatments by tricine and bicine were investigated with thermal modification. Along with some preliminary data on mechanical properties, the modifications which appeared in the wood structure were evaluated by infrared spectroscopy and biological studies according to EN113 and EN117 methodologies. The hierarchal study interpretation of FTIR suggested interactions between the bicine or tricine and the wood, which was partly supported by the analysis of volatile organic compounds (VOC), though other tests were not as conclusive. The potential of the method warrants further consideration, which will be described.
Ano: 2022
Número Páginas:
21p.
Autor(es): Jones, D.; Kr
Revista: Forests
Editor: MDPI
Volume:
Nº 13, volume 6.
Keywords: Biological properties; Infrared spectroscopy; Mechanical properties; Chemical treatment; Thermal; Maillard reaction; Wood
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EVOLUÇÃO DO DANO EM ENSAIOS EM MODELO FÍSICO DE UM TROÇO DO QUEBRA-MAR DO PORTO DE PENICHE
A avaliação da estabilidade do manto resistente de quebra-mares de taludes requer, na maioria dos casos, a realização de ensaios em modelo físico. Entre os diferentes métodos de avaliação da evolução da estabilidade, destaca-se a medição do volume erodido do manto resistente por ação da agitação marítima. Este volume pode ser determinado a partir de levantamentos consecutivos da envolvente dos taludes. Melby[1] apresentou uma fórmula para previsão da evolução do dano em quebra-mares de taludes com base nas características da agitação neles incidente. No presente estudo pretendeu-se utilizar um programa de ensaiosem modelo físico bidimensional semelhante ao programa que conduziu à referida fórmula aplicado a um caso de estudo correspondente a uma secção do quebra-mar do porto de Peniche.Os ensaios realizados fazem parte do projeto BSafe4Sea que visa desenvolver, testar e comprovar o conceito de previsão do comportamento estrutural de quebra-mares de talude, que constitui a base de um sistema inovador de apoio à decisão. Os ensaios tiverem como objetivo analisar a resposta da estrutura a diferentes estados de agitação incidentes, cujos resultados são fundamentais para o desenvolvimento d e formulações empíricas de previsão da evolução do dano.
Ano: 2022
Autor(es): Lemos, R.; Fortes, C. J. E. M.; Santos, J. A.; Mendonça, A. C.
Editor: FCT
Keywords: Formulação empírica; Volume erodido; Modelo físico; Evolução do dano
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Experimental and numerical evaluation of the wind load on the 516 Arouca pedestrian suspension bridge
The present work analyses the wind load effects on the 516 Arouca bridge, the world's longest pedestrian suspension bridge in 2020. Computational fluid dynamics (CFD) was used to model a range of wind incidence angles between -8
Ano: 2022
Número Páginas:
13pp.
Autor(es): Tadeu, A.; Marques da Silva, F.; Ramezani, B.; Romero, A.; Skerget, L.; Bandeira, F.
Revista: Journal of Wind Engineering and Industrial Aerodynamics
Editor: Elsevier
Volume:
220.
Keywords: wind load; suspension bridge; wind tunnel; CFD
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Experimental Evaluation of Brick Masonry Walls Strengthened with TRM (Textile Reinforced Mortar) Renders.
Old masonry buildings, which are frequently part of the cities-built heritage, are vulnerable to seismic actions. Thus, it is important to conduct efficient seismic strengthening interventions that allow maintenance of the existing building to minimize the environmental and economic impact. The use of reinforced renders is a simple and effective solution for seismic strengthening of this type of constructions. In this paper, several compositions of reinforced renders are analyzed, consisting of mortars with air lime, hydraulic lime, or cement binders, reinforced with steel mesh, fiberglass mesh and a natural fiber mesh. Additionally, the results of diagonal compression tests on three small wall specimens are presented, one of which is non-reinforced and the other two are strengthened with reinforced renders. The results of all tested walls are presented and compared, allowing us to evaluate the efficiency of the reinforced render on the wall shear strength.
Ano: 2022
Autor(es): Mera Marques, A.; Ferreira, J.; Candeias, P.; Veiga, M. R.
Revista: Buildings
Editor: MDPI
Volume:
2022.
Keywords: diagonal compression tests; reinforced renders; brick masonry walls
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Experimental Investigation of Air Bubble Curtain Effects on Water Wave Field
This paper studies the effects of an air bubble curtain on surface water waves. Water particle velocities and free surface elevations were measured simultaneously at two cross-shore sections downstream the air bubble curtain. Measurements were carried out for regular waves regarding different air bubble curtain configurations. Free surface elevations were measured using resistive gauges and the instantaneous velocities were acquired using an Acoustic Doppler Velocimeter (ADV). The characteristics of the free surface elevation, velocity field and turbulence are analyzed and discussed. The free surface elevation was found to be constantly attenuated by the air bubble curtain. The phase-averaged velocity profiles also depict the effect of the air bubbles in the flow field by generating milder longitudinal velocities (u) and by increasing the transverse component of the velocity (w). The increase in the turbulence intensity and the different energy spectrum produced by the air bubble curtain is also analyzed. The experimental results indicate that the thickness of the air bubble curtain and the total air flow rate affects the wave field.
Ano: 2022
Autor(es): Neves, D. R.; Brito, M.; Pires Silva, A.; Fortes, C. J. E. M.; Matos, J.
Editor: Trans Tech Publications Ltd, Switzerland
Keywords: Air bubble curtain, wave propagation, flow velocities, turbulence, wave flume
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Experimental study on the impact of double tilted Venetian blinds on indoor daylight conditions
One of the most important concerns when designing buildings as liveable spaces is the indoor comfort. Thisdepends on different factors, including daylight availability and discomfort glare conditions.The increasing use of glazing areas in the building
Ano: 2022
Número Páginas:
12p.
Autor(es): Gomes, M.; Santos, A. J.; M. Calhau
Revista: Building and Environment
Editor: Elsevier
Volume:
Building and Environment 225 (2022) 109675.
Keywords: Shading Devices; Indoor Environment; Double Tilted Venetian Blinds; Daylighting
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Experiments on the Sinking of Marine Pipelines on Clayey Soils
An experimental study was carried out to investigate seabed-pipeline interactions with regard to soil liquefaction. For a soil with a high proportion (30 to 60%) of fine sediment, four groups of tests were configured to reproduce soil liquefaction around pipelines for different initial pipe depths, pipe densities and wave conditions (wave height and period). The study focused on verifying the theoretically computed areas of soil failure by analyzing the sinking depths of the pipelines. The main findings are that a pipe with a submerged specific weight of less than half that of the soil will move up to the mudline; that the loss of soil loading capacity is more frequently evidenced in a fluid-like behavior of the soil than by an abrupt breaking of the soil matrix; and that the pipes which are totally buried will sink more than half-buried pipes. Moreover, wave action and the specific weight of the pipes seem to play more important roles in the expected behavior of the wave
Ano: 2022
Número Páginas:
25p.
Autor(es): Mendoza, E.; Neves, M. G.; Afonso, C.; Casarín, R.S.; Ramos, A.; Losada, M. A.
Revista: Journal Water
Editor: MDPI
Volume:
14(5), 704.
Keywords: Clayey soils; Pipeline
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