Papers
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Adhesives for on-site rehabilitation of Timber Structures
The use of adhesives to produce assembled structural joints in the building industry is increasing, particularly in the context of on-site rehabilitation of timber structures. On their own or together with steel or fibre reinforced polymer composite connecting materials, adhesives can provide low intrusive, fast, versatileand effective on-site repair or reinforcement interventions to timber structures. Most common applicationsinvolve sealing and repair of cracks, drying fissures and delamination of glued laminated members; replacement of decayed beam ends; strengthening of timber members; and repair and strengthening of mechanical timber joints. The performance of bonded joints highly depends on their design and detailing, surfaces preparation, selection and application of adhesives, and full compliance with their cure schedule. Therefore, the work should be carried out by well-informed, trained and certified operators following a QualityAssurance Program to ensure satisfactory end-product strength and durability.Despite some recent developments, the exploitation of the full potential for on-site bonded joints is mainlyrestrained at present by the lack of structural design guidance, standards for durability assessment and onsiteacceptance testing.This article discusses briefly the use of adhesives on the construction site in the context of structural repair and reinforcement; the requirements and practical difficulties in the work on site with regards to the strength and durability of the rehabilitated timber structure; and the consequent need for quality control. It also highlights the characteristics and requirements that must be fulfilled by structural adhesives and reinforcingmaterials; factors affecting performance and durability of bonded joints; and ways to improve adhesion and durability. Finally, it points out some research needs and future developments identified by the authors.© Koninklijke Brill NV, Leiden, 2010
Year: 2010
Number Pages:
27p.
Author(s): Cruz, H.; Custódio, J.
Volume:
nº 24.
Keywords: Quality control; Durability; Performance; Requirements; Limitations; On-site polymerized adhesives; Rehabilitation; Timber structures
Info
Adhesives for on-site rehabilitation of timber structures
The use of adhesives to produce assembled structural joints in the building industry is increasing, particularlyin the context of on-site rehabilitation of timber structures. On their own or together with steel orfibre reinforced polymer composite connecting materials, adhesives can provide low intrusive, fast, versatileand effective on-site repair or reinforcement interventions to timber structures. Most common applicationsinvolve sealing and repair of cracks, drying fissures and delamination of glued laminated members; replacementof decayed beam ends; strengthening of timber members; and repair and strengthening of mechanicaltimber joints. The performance of bonded joints highly depends on their design and detailing, surfacespreparation, selection and application of adhesives, and full compliance with their cure schedule. Therefore,the work should be carried out by well-informed, trained and certified operators following a QualityAssurance Program to ensure satisfactory end-product strength and durability.Despite some recent developments, the exploitation of the full potential for on-site bonded joints is mainlyrestrained at present by the lack of structural design guidance, standards for durability assessment and onsiteacceptance testing.This article discusses briefly the use of adhesives on the construction site in the context of structural repairand reinforcement; the requirements and practical difficulties in the work on site with regards to the strengthand durability of the rehabilitated timber structure; and the consequent need for quality control. It alsohighlights the characteristics and requirements that must be fulfilled by structural adhesives and reinforcingmaterials; factors affecting performance and durability of bonded joints; and ways to improve adhesion anddurability. Finally, it points out some research needs and future developments identified by the authors.
Year: 2010
Number Pages:
26.
Author(s): Cruz, H.; Custódio, J.
: Wood Adhesives
Editor: VSP / Brill Academic Publishers
Keywords: Timber structures; Quality control; Durability; Performance; Requirements; Limitations; On-site polymerized adhesives; Rehabilitation
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Changes in the wood boring community in the Tagus Estuary: a case study
In recent years an increased shift in the geographical range of species has been documented, which coincides with globalwarming. On the Portuguese coast the raising of sea-surface temperatures and salinity has also been affecting the intertidal species range. The aim of the present study was to assess changes in the wood boring community present in the Tagus Estuary by comparing data from present surveys with historical records from the 1960s and 1970s. A shift in the activity of wood boring species was observed in the Tagus Estuary. In recent surveys, the main agents of wood destruction in the Tagus were Limnoria tripunctata and Limnoria quadripunctata. In the 1960s and 1970s only L. tripunctata was reported as occurring in the Tagus estuary but it was not considered at threat to wooden structures exposed in the sea. The present predominance of limnoriids in the Tagus might be related to several factors but possibly the most important was the increase in salinity in the area, as limnoriids appear to be restricted to waters with salinities closed to that of seawater. The teredinid species also changed in the area. In the 1960s and 1970s Teredo navalis was reported as the only teredinid species occurring in the Tagus. In recent surveys however, this species was not found, instead two other teredinid species were present Lyrodus pedicellatus and Nototeredo norvagica. The absence of T. navalis in recent surveys might be related to competition with L. pedicellatus.
Year: 2010
Number Pages:
7p.
Author(s): Borges, L.; Valente, A.; Palma, P.; Lina Nunes
: Marine Biodiversity Records
Editor: Marine Biological Association of the United Kingdom
Volume:
Vol. 3.
Keywords: Salinity; Temperature; Tagus estuary; Teredinids; Limnoriids; Marine wood borers
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Development of a penetration test for timber impregnation products for use in old buildings
As concerns for the quality and durability of buildings are grow¬ing. solutions are needed to increase the likelihood of being able to preserve the physical and mechanical integrity of constructions. and this is more demanding when the building has historical value (1).Conspicuous among the anomalies currently most observed in buildings' timber structures are those caused by xylotrophic organ¬isms such as rot fungi and subterranean termites. as well as dry¬wood termites and woodworms, The first two occur in timber with high moisture content and the second two in dry timber Keeping timber in a good state of preservation and remediate an infection 01' infestation both normally require the use of chemical compounds [2], Treating the wood or using treated wood not only helps homeowners save money but also conserves forests (3.4], Details of these treatment products should nevertheless be duly noted after applicationUntil the early 1990s the use of CCA (chromated copper arse¬nate) compounds and active substances such as pentachlorophe¬nol. copper, tin or lindane applied in organic solvents (LOSP) was generalized [2-41. Although some of these formulations were very efficient at extending the life of wood. the health hazard to workers and the risk of environmental impact on the soil and landscape has to be seriously considered [3.4]. In the last few decades severerestrictions were therefore imposed on the use of many of the sub¬stances mentioned above in Europe [51. and in the USA where for instance, CCA was phased out of all new residential uses. from Jan¬uary 2004 [61,Some traditional products based on established practices are also in general use, They include linseed oil, a good water repellent finishing, and used motor oil. which is often applied (particularly in Portugal) in the preventive treatment of wood. though with very arguable effectiveness.Present day maintenance or rehabilitation interventions in old buildings will necessarily lead to the use of newer and more envi¬ronmentally benign products on existing timber (Fig. 1). However, the effectiveness of curative/preventive measures is often impaired by the presence of previous treatments or finishes, not always well documented and difficult to characterize.In this context. there is a need for a penetration test that would allow swift evaluation whether a particular new wood preserva¬tive eao be used, The test should also be of minimum disturbance to the structure under rehabilitation,
Year: 2010
Number Pages:
1095-1100pp.
Author(s): Henriques, M. D.; Nunes, L.; Brito, J.
Volume:
Construction and Building Materials, Vol. 24.
Keywords: Penetration test; Old buildings; Treatments; Wood
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É a secagem uma forma de protecção? Qual a influência da resinagem nas propriedades da madeira?
A preferência por Pinho bravo "resinado" / "não resinado" é ainda frequentemente expressa em Cadernos de Encargos. No entanto, as consequências para a qualidade da madeira de Pinheiro bravo (Pinus pinaster Ait.) resultantes da práctica de resinagem à vida (extracção moderada de resina, ao longo de muitos anos) têm sido alvo de discussão, não havendo consenso quanto à vantagem de um ou outro tipo de madeira. Tanto se assiste à preferência por madeira resinada, acreditando que o afluxo de resina aumenta a sua durabilidade, como à preferência por madeira não resinada baseada na sua hipotética maior resistência mecânica. Os conceitos "madeira seca" e "madeira tratada" correspondem a dois parâmetros distintos da especificação de uma madeira e não podem ser confundidos. A secagem da madeira pretende sobretudo minimizar a variação dimensional dos elementos após aplicação em obra, enquanto o tratamento (preservação) da madeira corresponde à introdução na madeira de um produto preservador destinado a conferir-lhe durabilidade adequada face ao risco de ataque de agentes biológicos.
Year: 2010
Number Pages:
2.
Author(s): Saporiti Machado, J.; Cruz, H.
: Revista Construção Magazine
Editor: Publindústria, Lda.
Volume:
nº 38.
Keywords: Propriedades da madeira; Resinagem; Secagem; Pinus pinaster; Pinheiro bravo
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Elaboração de cadernos de encargos: importância da especificação correcta da espécie florestal.
Na reabilitação de edificios antigos surge muitas vezes a necessidade de empregar madeira semelhante à original, de forma a minimizar o impacto da intervenção. Esta preocupação leva à especificação de madeira pela respectiva designação comercial, por se associar a essa designação um conjunto de características [estéticas, mecãnicas e de durabilidade) "garantidas".O resultado nem sempre é satisfatório de. vida,I) à qualidade [defeitos e característicasestruturais) variar entre lotes oriundos de diferentes localizaçóes geográficas com condições de crescimento distintas [Figura I) e mesmo dentro de um dado lote de madeira;2) à mesma designação comercial abranger um conjunto de material, por vezes muito diversificado.
Year: 2010
Number Pages:
34-35pp.
Author(s): Saporiti Machado, J.; Cruz, H.
: Revista Construção Magazine
Editor: Publindústria, Lda.
Volume:
Vol. 37.
Keywords: Espécie florestal; Cadernosde encargos
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First records of urban invasive Cryptotermes brevis (Isoptera: Kalotermitidae) in continental Spain and Portugal: Kalotermitidae) in continental Spain and Portugal
Occurrence of the West Indian drywood termite, Cryptotermes brevis, isregistered for the first time as established populations in Barcelona (Spain) and also additional information is given regarding a recent record from Lisbon (Portugal). This serious invasive termite pest wasdetected in five buildings in Barcelona, Spain and one building in Lisbon,Portugal.
Year: 2010
Number Pages:
637-640 pp.
Author(s): Lina Nunes; Gaju, M.; Krecek, Jan; Molero, R.; Marques Ferreira, M. T.; Bach de Roca, C.
: Journal of Applied Entomology
Volume:
Volume 134.
Keywords: Invasive biota; Iberian peninsula; Cryptotermes brevis
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Furacões e casas de madeira. Algumas razões para a destruição causada pelo Katrina.
A passagem do furacão Katrina pelo Golfo do México em 29 de Agosto de 2005 e os seus efeitos devastadores na costa sul dos Estados Unidos, em termos humanos e materiais, estão ainda bem presentes no terreno e na nossa memória colectiva.Este furacão foi dos mais fortes a atingir a costa dos Estados Unidos da América nos últimos 100 anos. Atingiu os estados de Luisiana, Alabama e Mississípi, sendo a inundação de cerca de 80% da cidade de New Orleans, em consequência da falha do sistema de diques que deveriam proteger a sua área metropolitana das águas do lago Pontchartrain, a face mais visivel da destruição causada.As inundações, os ventos fortes [superiores a 140mph, cerca de 22Skm/h] que lhe garantiram a classificação de furacão de grau 4 ao atingir a costa dos EUA, a chuva intensa e os detritos transportados pelo furacão destruíram ou tornaram inabitáveis mais de 300.000 casas na região costeira do Golfo.Os prejuízos estimados ascenderam a 96 mil milhões de dólares, com mais de 1800 mortos, 1,1 milhões de pessoas evacuadas e 770.000 deslocadas.Fora das zonas inundadas, o vento, a chuva e os detritos lançados pelo vento causaram extensos danos nas construções, entre elas um grande número de edifícios aligeirados com estrutura de madeira, que correspondem ao sistema de construção corrente de edifícios unifamiliares realizados muitas vezes em regime de auto-construção.Sem pôr em causa a extrema violência da tempestade, a destruição verifica da pareceu no entanto algo desproporcionada, suscitando em alguns meios considerações menos abonatórias relativamente às casas de madeira.A análise dos danos infligidos a estas casas e respectivos pormenores construtivos permitiria no entanto concluir que a devastação se deveu em grande medida a deficiências sistemáticas presentes nos edifícios, relevantes para a sua resistência ao vento, e que esta teria sido muito minimizada se a construção tivesse seguido os princípios e normas regulamentares de dimensionamento e de construção vigentes.Um estudo recentemente apresentado por Gopu e Levitan [1] sistematiza os danos so¬fridos durante o furacão pelas construções aligeiradas com estrutura de madeira e identifica as deficiências mais frequentemente encontradas nestes edifícios. Aponta ainda as principais lições a retirar e algumas medidas que poderiam ter evitado, e permitirão evitar de futuro, semelhantes níveis de destruição.O texto que se segue procura transcrever, no essencial, os resultados do estudo apresenta¬do por esses autores.
Year: 2010
Number Pages:
40-41 pp.
Author(s): Cruz, H.
: Revista Construção Magazine
Editor: Publindústria, Lda.
Volume:
nº 39.
Keywords: Concepção e execução; Resistência ao vento; Casas de madeira
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Influência da época de corte e da idade da árvore no desempenho de elementos estruturais de madeira: mitos ou factos?
A especificação da madeira para a construção assenta ainda hoje, muitas vezes, em critérios pouco objectivos, de difícil verificação e reduzida eficácia.Algumas especificações
Year: 2010
Number Pages:
33-34pp.
Author(s): Saporiti Machado, J.; Cruz, H.
: Revista Construção Magazine
Editor: Publindústria, Lda.
Volume:
nº 36.
Keywords: Elementos estruturais de madeira; Idade da árvore; Época de corte
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Numerical modeling of the load-deformation behaviour of doweled softwood and hardwood joints
This article presents a nonlinear finite element model developed to simulate the load-deformation behavior of wood joints when loaded by a dowel-type fastener. Particular attention was paid to the initialload-deformation behavior that had a significant influence on the joint stiffness, a joint property with a largeinfluence on the mechanical behavior of wood-based composite structures connected with semirigid joints.To obtain accurate predictions of joint deformation, the material models available in the literature were adapted and nonlinear deformations were taken into consideration during very early loading. The proposedmodel precisely describes the embedding behavior of different wood species and densities. Numerical results compared very well with those obtained in experiments. Based on this analysis, the recommendation is to obtain the material model inputs based on design values available in the literature.
Year: 2010
Number Pages:
480-489pp.
Author(s): Dias, A.; Kuilen, J.; Cruz, H.; Lopes, S.
: Wood and Fiber Science
Volume:
42.
Keywords: Finite elements method; Dowel-type fasteners; Constitutive law; Yield criterion; Wood joints; Nonlinear analysis
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Comunicação
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Electro osmotic pulsing technology (PLEOT)
Wood protection and control of infestation in buildings and other wooden cultural heritage objects is mainly based on chemical-, gas- and heat treatments. Degradation of wood is not only caused by fungi or bacteria but also by insects. Termites have been a potential risk to wooden structures not only in the warmer regions of our continents but also beyond the regions of their natural habitat due to transport of wood.A new environmental friendly wood protection system has been tested on wood destroying fungi and termites.Wood protection by means of electro osmotic pulsing technology (PLEOT) can preserve wood in service without using any chemical protection at all. The system can easily be installed and is very low in maintenance costs.The results show no mass loss of PLEOT protected beech and Scots pine sapwood samples exposed to the whiterot Trametes versicolor for 4 and 8 weeks. Termite attack could slightly be reduced by using this technology onScots pine sapwood samples.
Year: 2010
Number Pages:
5.
Author(s): Treu, A.; Lina Nunes; Duarte, S.; Larnoy, E.
Keywords: Térmitas subterrâneas; Fungos destruidores de madeira; Electro osmotic pulsing technology; Subterranean termites; Wood destroying fungi
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Estrategias no uso do encamisamento localizado com chapas de aço que previlegiem a ductilidade ou o aumento diferenciado da resistência
O reforço selectivo materializado através de encamisamento localizado com chapas de aço, em pilares de betão armado de secção rectangular, pode induzir o aumento de ductilidade ou promover o aumento da resistência e da ductilidade.Aborda-se nesta comunicação alguns dos factores que podem influenciar o aumento da resistência do encamisamento localizado com chapas de aço, permitindo ao projectista direccionar a intervenção apenas para o aumento de ductilidade, para o aumento de ductilidade e um aumento de resistência moderado (+20%), para o aumento da ductilidade e aumento significativo da resistência (+80%) e ainda a possibilidade de utilizar a ligação do encamisamento à base/nó como
Year: 2010
Number Pages:
263-265.
Author(s): Cardoso, A.
Editor: GPBE, LNEC
Keywords: Ductilidade; Reforço anti-sismico; Encamisamento localizado
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Influência na aderência aço-betão da alteração local da configuração geométrica das nervuras de armaduras de aço
N/A
Year: 2010
Number Pages:
12p.
Author(s): André, J.; Pipa, M.
Editor: Grupo Português de Betão Estrutural
Keywords: Ensaios pull-out; Configuração geométrica; Armaduras de aço; Aderência aço-betão
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Laboratory study of fipronil baits against Reticulitermes grassei (Isoptera: Rhinotermitidae)
Fipronil is currently used as chemical barrier against subterranean termites, in this paper their possible use as bait has been tested. Their efficacy with Reticulitermes grassei Clément in feed forced and feed choice tests has been analyzed, evaluating the mortality caused by administration of fipronil at 1 and 10 ppm (wt/wt). Our results show that 90% mortality is achieved at 6 days with feed forced test at 10 ppm and 16 days at 1 ppm; but with choice test the time to achieve that level of mortality is increased to 17 days for 10 ppm and only 50% mortality in 28 day is obtained with 1 ppm. Moreover the filter paper consumed by termite/day has been evaluated, founding a diminution of ingestion with the increase of concentration. This suggests a possible unpalatability of product at all tested concentrations. Fipronil is currently used as chemical barrier against subterranean termites, in this paper their possible use as bait has been tested. Their efficacy with Reticulitermes grassei Clément in feed forced and feed choice tests has been analyzed, evaluating the mortality caused by administration of fipronil at 1 and 10 ppm (wt/wt). Our results show that 90% mortality is achieved at 6 days with feed forced test at 10 ppm and 16 days at 1 ppm; but with choice test the time to achieve that level of mortality is increased to 17 days for 10 ppm and only 50% mortality in 28 day is obtained with 1 ppm. Moreover the filter paper consumed by termite/day has been evaluated, founding a diminution of ingestion with the increase of concentration. This suggests a possible unpalatability of product at all tested concentrations.
Year: 2010
Number Pages:
10p.
Author(s): Gaju, M.; Moyano, L.; Patiño, C.; Diz, J.; Lina Nunes; Bach de Roca, C.; Molero, R.
Keywords: Reticulitermes grassei; Termites; Baits; Fipronil
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Monotonic tests of structural carpentry joints
An experimental campaign on traditional diagonal front notched timber joints was carried out in order toassess their rotational behaviour. This campaign included ten different test conditions, comprising some of the mostfrequently observed configurations of the rafter and tie beam joint in Portuguese roof structures. The joints' mechanicalbehaviour was appraised with regard to their geometric parameters, presence of metal fastening devices and moisturecontent of timber. The experimental results show that the joint's response is different when opening or closing the skewangle and that specific load bearing mechanisms dictate the different performances exhibited by each typology.
Year: 2010
Number Pages:
6p.
Author(s): Palma, P.; Gomes Ferreira, J.; Cruz, H.
Keywords: Mechanical behaviour; Tests; Carpentry joints; Connections; Timber structures
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On the use of wood protection by means of electro osmotic pulsing technology against subterranean termites
Wood protection in the last century has been mainly based on chemical treatments. Additionally, the type of construction of wooden buildings and the choice of wood species plays an important role.Degradation of wood is not only caused by fungi or bacteria but also by insects. Termites have been a poten¬tial risk to wooden structures not only in the warmer regions of our continents but also beyond the regions of their natural habitat due to transport of wood.A new environmental friendly wood protection system has been tested. Wood protection by means of electro osmotic pulsing technology can preserve wood in service without using any chemical protection at all. The system can easily be installed and is extremely low in maintenance costs.The technology [EOP] has been preliminary tested on Scots pine sapwood [Pinus sylvestris] against subter¬ranean termites [Reticulitermes grasseiJ in the laboratory. Two choice and non-choice tests were carried out using different initial wood moisture content, 4 weeks of exposure and 6 replicates per variable.The results show heavy growth of mould fungi on wood samples with higher moisture content that probably contribute to higher termite mortality on wetter samples. EOP treatment strongly reduced the development of moulds and gave variable results in terms of termite survival and feeding.Further testing is needed to better understand the possibilities of this method to subterranean termite control.
Year: 2010
Number Pages:
1.
Author(s): Treu, A.; Lina Nunes; Larnoy, E.
Editor: Universidade Fernando Pessoa
Keywords: Subterranean termites; Electro osmotic pulsing technology
Info
Performance of Paraloid B72® combined with the application of biocides on wood degraded by fungi
When timber elements in heritage buildings are moderately degraded by fungi and assuming underlying moisture problems are solved, two actions can be taken: i) use a biocide product to stop fungi activity ii) consolidate the degraded elements so that the timber keeps on fulfilling its structural and decorative functions. Indeed, the option of maintaining in the building the original (even though deteriorated) timber has been gaining more and moreimportance, as the loss any element may contribute to the loss of the historical identity of the building.This paper presents the laboratory work performed with the purpose of understanding the mechanical performance of maritime pine timber degraded by fungi (with mass losses lower than 20%) when subjected to consolidation by impregnation with Paraloid B72®, combined with the previous application of a biocide.Three commercially available pre-selected biocide products were used: a light organic solvent (X), a boron water-based (BC) and a water-based emulsion (A). After the products were applied to five sets of specimens (Control, PB72, X+PB72, BC+PB72, A+PB72) these were subjected to mechanical tests: axial compression test (NP618) and resistance to indentation (ISO 3350). Four similar sets of replicates were subjected to an evaporation ageing procedure (EN73) after the products were applied and equally tested.An increase in mechanical strength was observed for the consolidation product with no significant influence of the previous use of biocide product. The specimens subjected to ageing showed a slightly better general mechanical performance than those not aged.
Year: 2010
Number Pages:
8.
Author(s): Henriques, J. D.; Lina Nunes; Brito, J.
Keywords: Biocidas; Madeira degradada por fungos; Biocides; Wood degraded by fungi; Paraloid b72®
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Predicting the mechanical behaviour of solid pine timber elements thyough non and semi-destructive methods
Timber elements can be foreseen as lengthwise composites of clear and knot zones, being the clear wood zones greatly responsible for stiffness and the weakest zones (worst knots shown by the timber element) for the ultimate strength capacity. In the present study non destructive techniques (ultrasounds and visual grading) and semi-destructive techniques (tension meso-specimens and core drilling) are used and tested as tools for evaluating clear wood properties. These properties are then used to predict the global modulus of elasticity of maritime pine timber beams. The results obtained delivered important information concerning variability within and between timber pieces. The non and semidestructive techniques used have shown a reasonable capability to predict the clear wood properties and to deliver a good prediction of the global bending modulus of elasticity.
Year: 2010
Number Pages:
6p.
Author(s): Saporiti Machado, J.; Palma, P.
Keywords: Tension testing; Meso-specimens; Core drilling; Ultrasounds; Visual grading
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Preventing decay in termite monitoring stations
In-ground monitoring stations and termite baits are widely used in the southern United States with the intent of detecting and eradicating subterranean termite activity near buildings. These stations comprise a wood (or other cellulose material) substrate (monitor) and perhaps a termiticidal toxicant (bait) held m a plastic cage that allows for both, easy examination and access by termites. The usual practice is to inspect the station monitors for termite aetiv1ty every few months. If termites are detected, a bait is added to ar replaces the untreated monitor. However, in addition to termite attack, the monitors are subject to fungal decay, and rapid decay in high hazard areas is interfering with the usefulness of this baiting approach.This paper reports on an evaluation of the relative decay susceptibility of termite baiting systems used in commercial monitoring stations. Some monitors are very susceptible to wetting and fungal decay. corroborating anecdotal evidence from the field. It was eonc1uded that decay in high hazard areas is likely to interfere with the usefulness of some of these systems. To be used successfully, possible approaches to overcome the decay issue are: careful selection of the system used; placement on or above ground rather than in the ground; recognition that monitors and/or baits need to be changed every few months; avoiding remote sensing systems that do not allow a visual check of the monitor; developing durable m0nitors and baits, e.g., with the addition of a non-termite-repellent fungicide.
Year: 2010
Number Pages:
12p.
Author(s): Taylor, A.; Kim, J.; Duarte, S.; Lina Nunes; Lloyd, J.
Keywords: Termiticide; Subterranean termites; Monitor stations; Fungicide; Decay; Baits
Info
Reabilitação de ligações em estruturas antigas de madeira - avaliação experimental
Apresentam-se os resultados de uma campanha experimental realizada no LNEC com oobjectivo de avaliar a viabilidade técnica de algumas soluções de reparação e reforço deligações tradicionais em estruturas de madeira, por meio entalhes, com e sem ferragens. Os resultados obtidos permitem avaliar o desempenho destas intervenções relativamente ao comportamento das ligações originais.
Year: 2010
Number Pages:
11p.
Author(s): Palma, P.; Garcia, H.; Appleton, J.; Cruz, H.
Keywords: Reforço; Reparação; Ensaios; Ligações; Estruturas de madeira
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Books
Info
Térmita-de-madeira-seca. West Indian drywood termite
N/A
Year: 2019
Number Pages:
144-145pp.
Author(s): Duarte, S.; Lina Nunes
: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Acoriano da Cultura
Keywords: Cryptotermes brevis
Info
Térmita-de-pescoço-amarelo. Yellow-necked drywood termite; European drywood termite
N/A
Year: 2019
Number Pages:
146-147pp.
Author(s): Duarte, S.; Lina Nunes
: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Açoriano da Cultura
Keywords: Kalotermes flavicollis
Info
Térmita-subterrânea-americana. Easten subterranean termite
N/A
Year: 2019
Number Pages:
148-149pp.
Author(s): Duarte, S.; Lina Nunes
: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Açoriano da Cultura
Keywords: Reticulitermes flavipes
Info
Térmita-subterrânea-ibérica. Iberian subterrarean termite
N/A
Year: 2019
Number Pages:
150-151pp.
Author(s): Duarte, S.; Lina Nunes
: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Açoriano da Cultura
Keywords: Reticulitermes grassei
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Estudo histórico e científico da Xiloteca da Academia das Ciências de Lisboa construída por José Aniceto Rapozo - nota preliminar
O Museu da Academia das Ciências de Lisboa possui uma preciosa xiloteca assinada pelo Mestre dos marceneiros portugueses, José Aniceto Rapozo contendo 1213 amostras de madeiras do Brasil e 12 de outras origens. A sua importância no progresso do conhecimento dos recursos florestais do Brasil naviragem dos séculos dezoito e dezanove conduziu ao estudo em curso. Dada a devastação verificada em vastas áreas florestais brasileiras, surgem dificuldades por certas espécies poderem ter distribuiçãogeográfica diferente (com eventual extinção, geral ou localizada), por insuficiência do material de comparação, e por ambiguidade das designações comerciais.Foi possível identificar esta xiloteca como uma de quatro encomendadas a Aniceto Rapozo pelo Príncipe Regente. A análise das amostras de madeira e a informação documental mostram que a colecçãotem por base uma remessa de 5008 amostras de madeiras do Brasil enviada em 1784 para o Arsenal Real do Exército, em Lisboa, pelo Vice-Rei do Brasil, Luís de Vasconcellos e Souza.O valor científico do conjunto é evidenciado pela identificação botânica das espéciesrepresentadas. Na situação actual, a identificação das espécies florestais representadas na amostragem foiinteiramente conseguida em 14% dos casos, conseguida mas ainda por confirmar em 27%. Dado o carácter preliminar deste estudo, os seus resultados serão ulteriormente publicados com mais pormenor. Among the Lisbon Academy of Sciences Museum collection there is a valuable xylarium by theleading Portuguese master cabinet-maker José Aniceto Rapozo (1756-1824), comprising 1213 wood samples from Brazil plus 12 from elsewhere. This collection is most important since it allows us to improve the knowledge on Brazilian forest resources by the end of the eighteenth century and thebeginning of the next. This study aims to establish its historical framework and scientific value. Owing tooverexploitation and even devastation of very large forest areas in Brazil, difficulties for our study aroseeither as some species may have now a different geographical distribution (and eventually may have underwent local or general extinction), by lack of adequate comparison material, or because of ambiguityof the commercial names.Results so far obtained allowed us to recognize the xylarium as one of the four commanded Rapozo by the Regent Prince, later King João VI (1767-1826). Taking into account the wood samples analyses as well as bibliographic data it is possible to conclude that the collection was prepared from a set 3 of 5008 Brazilian wood samples sent to the Royal Arsenal in Lisbon in 1784 by the Brazil
Year: 2013
Number Pages:
9.
Author(s): Saporiti Machado, J.; Antunes, M.
Editor: Academia das Ciências de Lisboa (ACL)
Keywords: Identification; History; Brazil; Woods; Xylarium; Lisbon academy of sciences; Identificação; História; Brasil; Madeiras; Xiloteca; Academia das ciências de lisboa
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Capítulo de Livro
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A Review of Laboratory Tests to Evaluate Agro-Industrial Wastes Properties as Building Materials
This work collects information about laboratory tests to evaluate the properties of agro-industrial wastes used for thermal insulation building materials considering them individually and in composits. It focuses on bio-susceptibility, as one of the main aspects to consider for bio-based building products.
Year: 2023
Number Pages:
2p..
Author(s): Cintura, E.; Lina Nunes; Faria, P.
: Testing and Experimentation in Civil Engineering
Editor: Springer Nature
Volume:
Volume 41.
Keywords: Test methods; Bio-wastes; Bio-susceptibility; Bio-based materials
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Innovative Durability Tests on Construction Materials
Innovation in structures and construction materials demands a more accurate performance analysis during the life cycle. In addition, climatic changes pose new challenges to civil infrastructures that were not so relevant in the past. In most cases, the traditional test methods cannot accurately assess the complex phenomena involved in durability. The modern and complex factors require a different approach to durability analysis. The purpose of this chapter is to present innovative durability tests on construction materials: wood; rammed earth, cob and unfired blocks; natural stone; bituminous binders and mixtures; and Fibre Reinforced Polymers (FRP) to concrete bonded connections. Most of these tests concern the accelerated simulation of the main phenomena involved in durability performance
Year: 2023
Number Pages:
53-73pp..
Author(s): Chastre, C.; Faria, P.; Neves, J.; Ludovico-Marques, M.; Biscaia, H.; Lina Nunes
: Advances on Testing and Experimentation in Civil Engineering
Editor: Springer
Keywords: Performance; Innovation; Durability; ccelerated durability tests; Accelerated durability tests; Ageing techniques
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Optimisation of Production Parameters to Develop Innovative Eco-efficient Boards
Laboratory tests were carried out to define production parameters of innovative eco-efficient composites made up of hazelnut shells as aggregate and a sodium silicate solution as adhesive. The aim was to maximize the content of bio-aggregates and minimize the amount of adhesive, guaranteeing the feasibility of producing samples. Therefore, after preliminary testing, the percentages of hazelnut shells and the sodium silicate solution were kept constant: 70% and 30% of the total volume, respectively. However, the characteristics of the considered composites did not allow the production of uniform samples. The sodium silicate solution was not rapidly absorbed by the bio-aggregates; during the drying process, it was deposited on the bottom side of the samples. The uniformity of the samples is required to guarantee a correct evaluation of their performance and future homogeneous panels. Hence, different production parameters were investigated, such as drying at T
Year: 2023
Number Pages:
11p..
Author(s): Cintura, E.; Faria, P.; Molari, L.; Lina Nunes
: Bio-Based Building Materials
Editor: Springer
Volume:
Volume 45.
Keywords: Sodium silicate; Hazelnut shells; Bio-waste
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Testing Durability on Construction Materials
The durability of construction materials is a key concern and can be related to different actions such as weathering conditions outdoors enhanced by climatic change, chemical and biological attack, abrasion, and other conditions of service over time. Frequently, several actions develop simultaneously, making it difficult to reproduce in situ conditions in laboratory. Furthermore, testing to assess durability depends largely on the nature of the material itself or on the way it has been assembled with other materials. The ageing techniques to assess long-term durability performance of construction materials are based on accelerated durability tests, which include, for example, thermal stress, freeze
Year: 2023
Number Pages:
29-51pp..
Author(s): Chastre, C.; Faria, P.; Neves, J.; Ludovico-Marques, M.; Biscaia, H.; Lina Nunes
: Advances on Testing and Experimentation in Civil Engineering
Editor: Springer
Keywords: Wood; UV radiation; Frost; Weathering; Salts; Natural stone; Polymeric composites; Clayish materials; Cementitious composites; Brick; Bituminous binders and mixtures; Biological agents
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Structural gluing of portugueses timbers
This paper presents an overview of research carried out to assess the bonding suitability of Portuguese timbers.Most work developed in the last decades has focused Maritime pine timber, due to its traditional use in building construction, good mechanical properties and availability. Untreated, as well as preservative treated Maritime pine have been studied, as its impregnability allows deep treatment suitable for applications in Use Classes 3 and 4.Recent results on bonding preservative treated Maritime pine wood are discussed.Preliminary results regarding other species that are becoming available in the Portuguese market are also presented, as an attempt to reduce pressure on Maritime pine timber as well as to seek more valuable alternatives for their traditional uses.
Year: 2018
Number Pages:
171-183pp.
Author(s): Cruz, H.; Martins, C.; Dias, A.
: Timber: Bonds, Connections and Structures
Editor: Material Testing Institute (MPA), University of Stuttgart
Keywords: Structural gluing; Portuguese timbers
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Tese de Doutoramento
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Caracterização da aderência de varões nervurados sujeitos a ações repetidas e alternadas
No presente trabalho apresentam-se os resultados mais relevantes obtidos num programa experimental desenvolvido no LNEC com o objetivo de caracterizar a aderência dos varões nervurados do tipo A500NR SD existentes no mercado, fundamentalmente para melhorar a modelação do comportamento dos elementos de betão armado de zonas críticas de estruturas inseridas em zonas sísmicas.O programa experimental desenvolvido pretende simular as condições de aderência existentes num varão horizontal de uma ligação viga-pilar e tem como principais variáveis varões de dois diâmetros frequentemente utilizados (16 e 25 mm), dois níveis diferentes de área relativa das nervuras (A e B) e duas classes de betão (C1 e C2), ambos representativos do betão utilizado nas construções mais relevantes.Os resultados obtidos quer nos ensaios monotónicos quer nos ensaios cíclicos apontam para um decréscimo da tensão de aderência com o aumento do diâmetro da ordem dos 10%. O aumento da área relativa das nervuras transversais traduz-se num incremento da tensão máxima de aderência da ordem dos 15%, com uma redução do deslizamento que ronda os 15%. Nesse sentido, este estudo propôs que, no caso dos varões com maior área relativa das nervuras, a tensão de aderência máxima possa variar entre 2,35 e 2,65 vezes a raiz quadrada da resistência do betão à compressão e que o patamar onde a tensão de aderência é máxima se situe entre 0,5 e 1,5 mm de deslizamento.Explorou-se também o fenómeno da entrada em cedência da armadura tendo-se concluído que, em provetes que pretendem simular as condições de aderência existentes num varão horizontal de uma ligação viga-pilar, a entrada em cedência da armadura conduz a uma redução da tensão de aderência máxima inferior a 10%, quer regime monotónico quer em regime cíclico.
Year: 2014
Number Pages:
435p.
Author(s): Louro, A. S.
Keywords: Estudo experimental; Modelação analítica; Ações repetidas e alternadas; Varões nervurados; Aderência
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Tratamento e consolidação de madeira de pinho degradada em elementos estruturais de edifícios antigos
O presente trabalho de investigação refere-se à conservação de elementos estruturais de madeira medianamente degradados por fungos em edifícios antigos. Propõe-se estudar a compatibilidade entre produtos de tratamento e de consolidação por impregnação, aplicados sequencialmente. A avaliação do processo foi realizada maioritariamente em laboratório e na óptica do desempenho mecânico conjunto da madeira e produtos aplicados, por intermédio de ensaios físico-mecânicos destrutivos e não destrutivos e também por ensaios mecânicos não destrutivos realizados in situ. Foram utilizados produtos comerciais, aplicando-os às espécies de madeira correntemente encontradas nos edifícios antigos da zona de Lisboa: Pinho bravo e Casquinha. Procedeu-se à avaliação mecânica de madeira nova e antiga, em estado são e degradado; ao desenvolvimento de um método de medição da profundidade de penetração de produtos de tratamento; à avaliação da capacidade consolidante de madeira degradada por produtos poliméricos fluidos e à avaliação da sua actuação conjunta, estudada com e sem envelhecimento artificial. Os resultados obtidos indicaram significativos aumentos de capacidade mecânica da madeira degradada, quando submetida a tratamento e consolidação Este trabalho desenvolve, assim, uma proposta de solução para a madeira que não se encontra sã, mas que ainda possui capacidade resistente, não necessitando, por isso, de ser removida. O processo de tratamento e consolidação promove resistência aos agentes biológicos e, simultaneamente, recuperação de alguma resistência mecânica da madeira, conferindo-lhe capacidade para continuar em serviço.
Year: 2011
Number Pages:
404
Author(s): Henriques, M. D.
Keywords: Elementos estruturais; Resistência mecânica; Tratamento; Consolidação; Edifícios antigos; Conservação; Degradação por fungos; Madeira
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Foraging ecology of Reticulitermes grassei (clément) with re feren ce to its management as a pest of timber
Subterranean termites from the genus Reticulitermes are an important pest ofwood in service throughout southern Europe and elsewhere. For effective termitecontrol with long term protection but minimal environmental damage, newintegrated approaches to termite management are needed. Baiting-based systemsseem to be promising non-traditional methods for termite control, targeting thecolony as a whole. However, control through baiting is only feasible when it isknown that the toxicant can be transferred to all the colonies foraging on theinfested area and also throughout each individual colony. Accordingly, the workdescribed is specifically designed to achieve a better understanding of thedistribution and delimitation of colonies within a population of Reticulitermes,with parallel insights into foraging behaviour and colony organization.Initially, the species/subspecies spectrum present within the notionalReticulitermes group in Portugal was reassessed. It was shown that Reticulitermesgrassei is the only species encountered. Foraging activity was then assessed in anexperimental woodland site over two successive annual cycles, both by thesampling of natural lying dead wood and by a standard baiting grid. R. grasseiseem to select wood with larger diameter, with an apparent preference for materialalready decayed by fungi. Both termite and fungal attack on wood seems to bepromoted by higher moisture levels, such as prevail in larger litter items andduring seasonal rains. Termites were unable to detect and direct their foragingtowards sound wood in laboratory conditions, suggesting that the network ofinfochemical signals is more complex than just volatiles emanating from soundwood. Mark-release-recapture (MRR) was used to delineate foraging groups,which were then allocated to their parent colonies by the use of microsatellitemarkers. The results suggest that resource sharing is a facultative behaviour,specifically when food is not a limiting factor for colony development. Theimplications of all these findings for bait technology and protocols are discussed,with reference to the local population ecology of Reticulitermes.
Year: 2009
Author(s): Nobre, T.
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Relatório Científico
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Project
The project CircularBuild -
Year: 2023
Author(s): Lina Nunes; Duarte, M.; Duarte, S.
Keywords: Moulds; Biological durability; Subterranean termites; Decay fungi; AGEPAN® DWD PROTECT
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Monitor
Relatório final do projeto PTDC/ECM/099121/2008
Year: 2014
Author(s): Lina Nunes; Duarte, S.; Saporiti Machado, J.
Keywords: Deteção; Monitorização; Térmitas subterrâneas; Uso sustentável de estruturas de madeira
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Materiais metálicos. Ensaio de tracção. 2ª Parte: Verificação do sistema de medição da força da máquina de ensaio de tracção. Projecto de versão portuguesa da Norma Europeia EN 10002-2 (1991)
O presente trabalho apresenta um projecto de versão portuguesa da Norma Europeia EN 10002-2, e insere-se numa série de estudos programados pelo autor, enquanto coordenador da normalização nacional no domínio dos ensaios mecânicos, físicos e não-destrutivos de materiais metálicos.O texto do projecto de norma apresentado consiste na versão final de uma proposta redigida pelo autor, na sequência dos estudos efectuados ao nível da Comissão Técnica de Normalização competente.
Year: 1992
Author(s): Baptista, A. M.
Keywords: Normalização; Ensaio de tracção; Materiais metálicos
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Materiais metálicos. Ensaio de tracção. 5ª Parte: método de ensaio a temperatura elevada. Projecto de versão portuguesa da Norma Europeia EN 10002-5 (1991)
O presente trabalho apresenta um projecto de versão portuguesa da Norma Europeia EN 10002-5, e insere-se numa série de estudos programados pelo autor, enquanto coordenador da normalização nacional no domínio dos ensaios mecânicos, físicos e não-destrutivos de materiais metálicos.O texto do projecto de revisão apresentado consiste na versão final de uma proposta redigida pelo autor, na sequência dos estudos efectuados ao nível da Comissão Técnica de Normalização competente.
Year: 1992
Author(s): Baptista, A. M.
Keywords: Normalização; Ensaio de tracção; Materiais metálicos
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Metrologia de Forças. Participação do LNEC no 2nd WECC Audit on Force Measurement
O presente relatório descreve a participação do LNEC no programa europeu de intercomparação de calibrações de forças
Year: 1992
Author(s): Baptista, A. M.
Keywords: WECC Audit; Metrologia de forças
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Materiais metálicos. Arames. Ensaio de enrolamento. Projecto de revisão da NP 850 (1985)
O presente trabalho apresenta um projecto de revisão da Norma Portuguesa NP 850 (1985)
Year: 1991
Author(s): Baptista, A. M.
Keywords: Ensaio de Enrolamento; Arames; Materiais metálicos
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Materiais metálicos. Ensaios de resistência mecânica. Símbolos. Projecto de revisão da NP 386 (1965)
O presente trabalho apresenta um projecto de revisão da Norma Portuguesa NP 386 (1965)
Year: 1991
Author(s): Baptista, A. M.
Keywords: Normalização; Simbologia; Ensaios mecânicos; Materiais metálicos
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Materiais metálicos. Tubos. Ensaio de Abocardamento. Projecto de revisão das NP 449 (1966) e NP 451 (1966)
O presente trabalho apresenta um projecto de revisão das Normas Portuguesas NP 449 (1966)
Year: 1991
Author(s): Baptista, A. M.
Keywords: Normalização; Ensaio de Abocardamento; Tubos; Materiais metálicos
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Materiais metálicos. Tubos. Ensaio de Achatamento. Projecto de revisão da NP 450 (1966)
O presente trabalho apresenta um projecto de revisão da Norma Portuguesa NP 450 (1966)
Year: 1991
Author(s): Baptista, A. M.
Keywords: Normalização; Ensaio de Achatamento; Tubos; Materiais metálicos
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Materiais metálicos. Tubos. Ensaio de Dilatação de Anéis. Projecto de Norma Portuguesa
O presente trabalho apresenta um projecto de Norma Portuguesa relativo ao ensaio de dilatação de anéis de tubos metálicos, e insere-se numa série de estudos programados pelo autor, enquanto coordenador da normalização nacional no domínio dos ensaios mecânicos, físicos e não-destrutivos de materiais metálicos, com a finalidade de preencher lacunas da Normalização Portuguesa neste domínio que a indústria e as instituições ligadas ao controlo da qualidade considerem ser mais urgente colmatar.O texto apresentado consiste na versão final de uma proposta redigida pelo autor, na sequência dos estudos efectuados ao nível da Comissão Técnica de Normalização competente.
Year: 1991
Author(s): Baptista, A. M.
Keywords: Normalização; Ensaio de dilatação de anéis; Tubos; Materiais metálicos
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Outro
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ISOLPRO LIGHT: Painel compósito de cimento leve constituído por cimento, areia e grânulos de poliestireno expandido (EPS)
N/A
Year: 2024
Author(s): entidade LNEC
Keywords: Europa; Material compósito; Isolamento acústico; Isolamento térmico; Elemento de estrutura; Painel prefabricado
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BALBOA 400SD (A400 NR de Ductilidade Especial)
N/A
Year: 2023
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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BALBOA 500SD (A500 NR de Ductilidade Especial
N/A
Year: 2023
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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BALBOA 500SD (A500 NR de Ductilidade Especial)
N/A
Year: 2023
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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EURAROL 500SD (A500 NR de Ductilidade Especial)
N/A
Year: 2023
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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MEGASA 500SD
N/A
Year: 2023
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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MEGASA 500SD E - SEIXAL (A500 NR de Ductilidade Especial)
N/A
Year: 2023
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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NERVACERO 500SD (A500 NR de Ductilidade Especial)
N/A
Year: 2023
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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CELSAMAX 500SD - NERVACERO (A500 NR de Ductilidade Especial)
N/A
Year: 2022
Author(s): entidade LNEC
Keywords: Documento de classificação; Ductilidade; Varão nervurado; Varão para betão armado
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MEGASA 500SD
N/A
Year: 2022
Author(s): entidade LNEC
Keywords: Documento de classificação; Varão nervurado; Varão para betão armado; Ductilidade
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