Publicações

Os ensaios de ligações aparafusadas realizados no LNEC no âmbito do projeto de investigação TimQuake abrangeram várias combinações de espécie (Pinus sylvestris e Picea abies) e teor de água da madeira, geometria da ligação (madeira-aço-madeira ou aço-madeira-aço), regime de carregamento e nível de tração axial do ligador.Este artigo apresenta o programa experimental e discute os resultados obtidos nos ensaios monotónicos, à luz do dimensionamento das ligações segundo o Eurocódigo 5 (EC5).Conforme previsto, as ligações com parafusos menos esbeltos apresentaram maior propensão para desenvolverem rotura frágil, mesmo seguindo a pormenorização recomendada no Eurocódigo 5. Os resultados dos ensaios con

A aplicação de produtos de aço em construções de betão armado em Portugal depende da sua prévia Classificação e Certificação.O presente artigo apresenta um estudo comparativo sobre graus de confiança conferidos pelos planos de amostragem e pelos critérios de aceitação estabelecidos nos Procedimentos de Certificação aplicados em Portugal e nas normas EN 10080 e ISO 6935-2, para diferentes características essenciais dos varões de aço, em cada ação de controlo deste produto. Os graus de confiança associados a amostras com resultados nãoconformes são discutidos em pormenor, apresentando-se vários quadros e figuras com a representação da probabilidade de rejeição (ou de aceitação) de lotes não conformes, em função da dimensão das amostras e do número de resultados individuais não conformes. É ainda analisado o critério de avaliação estipulado no Anexo Nacional da EN 13670, sobre a execução de estruturas de betão, para os ensaios de receção dos varões em obra.

The impact of Tribolium castaneum on the quality and technological suitability of bread-making wheat flour was evaluated. The aim of this study is to investigate whether insect-infested flours can be used, after pest removal, avoiding the common use of insecticides and flour waste. The tests were carried out with wheat flour infested red flour beetle with 500 adults/kg (N1), 1000 adults/kg (N2) and 2000 adults/kg (N3), for two weeks. Flour color, total starch, protein and water contents, mineral composition and flour acidity were studied. The technological properties of the respective doughs and of bread were characterized. The results showed that infested floursacidity was significantly higher (N1, N2 and N3 = 0.3 g H2SO4/100 g) than the control (0.1 g H2SO4/100 g), the total starch content decrease, from 78 g (control) to 70 g/100 g dm (N3), and protein content did not significantly change, 7 g/100 g (control) to 8 g/100 g (N2); flour infested showed darker greyish tone which colour differences

Insulation materials are fundamental for decreasing energy losses and guaranteeing thermal and acoustic comfort in buildings, which may significantly contribute to decreasing the energy consumption related with poor thermal building conditions. These insulation materials should have a low susceptibility to biological degradation agents to decrease the risks of degradation of other construction materials, as well as decrease possible health risks related with the development of noxious biological degradation agents regarding indoor air quality, for example, or decrease possible structural risks posed by those agents. The present study aimed at evaluating the susceptibility of several insulation materials to mold growth and subterranean termites

The yield strength of the steel rebars is one of their essential characteristics considered in the safety checking of reinforced concrete structures. It may present substantial variations, due to the influence of different factors This paper presents a statistical study of the yield strength Re of A500 steel rebars used in Portugal, from three different ductility classes according to the Eurocode 2. The statistical distributions of Re are based on a very large collection of more than 30 000 test results, obtained from 1994 to 2019. These rebars were produced by several dozens of different manufacturers, mostly from foreign countries. The detailed data presented here, about the main statistical parameters of the Re distributions and their variation with the rebars grade and diameter, for instance, may be useful for different studies,such as structural refurbishment projects to evaluate the safety of existing structures, in their actual state or after their restoration.

The identification of the main degradation agents and knowledge of the degradation mechanisms and long-term performance of ETICSs are of fundamental importance for the sustainable and efficient use of these systems. This review article presents the state of the art related to the durability of ETICSs, defining the required bases for their sustainable and efficient use. The aim is to identify the most common anomalies detected on ETICS façades and their causes, to overview the performance of ETICS, their performance parameters and requirements and to identify the most significant degradation mechanisms and the related failure modes. The results show that ETICS application is a key aspect in the performance and durability of the system, since most of the anomalies can be prevented with proper design, execution and appropriate assembly of the system components. The greatest drawbacks lie in dealing with enhancing the water resistance over time, which leads to extensive cases of anomalies, and improving the mechanical and thermal performance during the life cycle. Further research is needed to evaluate the synergistic effect of several degradation agents and mechanisms toward a development in optimized durability assessment methodologies for ETICSs.

A aplicação de argamassas de desempenho térmico melhorado em sistemas multicamada de isolamento térmico pelo exterior tem sido cada vez mais frequente, quer em construção nova, quer na reabilitação térmica de fachadas de edifícios. Com o presente estudo, pretende-se avaliar a resistência à biocolonização e o desempenho à água de três argamassas térmicas aplicadas em sistemas multicamada. Os resultados demonstram a importância de um bom desempenho de todos os componentes do sistema para um aumento da eficiência e durabilidade do conjunto.

Screening tests were developed or adapted from RILEM recommendations, standards andpast studies, and carried out to characterize some agro-industrial wastes and to assess their feasibilityas aggregates for eco-efficient building composites. Spent coffee grounds, grape and olive presswaste and hazelnut shells were used, as well as maritime pine chips as control material. Particle sizedistribution, loose bulk density, thermal conductivity and hygroscopicity properties were analysed.The selected bio-wastes did not show good thermal insulation properties if compared with some bio-wastes already studied and used for thermal insulation composites. Values of loose bulk density andthermal conductivity were between 325.6

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.

Multilayer external wall thermal insulation systems are widely used in new constructions and for the retrofittingof building façades. Despite the increasing use as constructive solution, significant anomalies have beenfrequently identified on these systems only few years after their application, raising questions on their long-term durability. This paper focuses on the effects of one-year natural ageing and artificial ageing through hygrothermal cycles (heat/rain and heat/cold) on the water performance (capillary water absorption and drying kinetics), bio-susceptibility (mould development) and surface properties (colour, gloss, and roughness) of four multilayer external wall thermal insulation systems (three ETICS and a thermal rendering system). Results showed a significant loss of surface hydrophobicity after ageing. Considering the 24 h water absorption results,an increase up to 73% and 432% was obtained for the naturally and artificially aged systems, respectively, and when compared to the reference unaged systems. The drying kinetics was affected by ageing, with increases of the drying resistance ranging between 47% and 122% after artificial ageing. Traces of mould growth were observed on the artificially aged systems; however, no growth was detected on either the unaged or the one-year naturally aged systems. Substantial colour change for all systems after ageing was observed, confirming aesthetic alteration. Results contribute towards the development of implemented artificial ageing protocols, as well as for the delivery of multilayer thermal systems with enhanced performance and durability.

A tensão de rotura à tração dos aços dos varões para betão armado constitui uma das propriedadesmecânicas consideradas na análise do comportamento das estruturas de betão armado.O presente artigo apresenta um estudo estatístico dos valores da tensão de rotura dos aços dos varõespara betão armado obtidos pelo Laboratório Nacional de Engenharia Civil ao longo de 25 anos, noâmbito do controlo periódico de varões da classe A400 decorrente das Ações de Acompanhamento daCertificação destes produtos. Com base nestes valores, são indicadas as distribuições globais da tensãode rotura para cada tipo de varões controlados (A400 NR e A400 NR SD).No entanto, a tensão de rotura pode apresentar variações significativas, que dependem do tipo devarão, da composição química do aço, da origem dos varões, do diâmetro dos varões e dos métodosde ensaio utilizados na sua determinação, por exemplo. Os varões de aço utilizados numa obraespecífica provêm frequentemente de um único fabricante e de um número limitado de lotes deprodução. Por este motivo, numa determinada construção ou até numa parte dela, a distribuição dosvalores da tensão de rotura pode diferir da distribuição global referente a esse tipo de aço, atrás referida.A fim de se avaliar a influência da origem dos varões, este artigo apresenta também diversos exemplos dedistribuições de resultados correspondentes a um único fabricante de cada um dos tipos de varõesanalisados. São também apresentados os valores dos parâmetros estatísticos das distribuições individuaisde resultados de todos os fabricantes dos varões analisados. Esta informação fornece uma noçãoadicional e mais realista sobre a resistência dos varões A400 certificados em Portugal. Poderá, por isso,constituir uma ferramenta útil para a avaliação futura das construções em betão armado realizadasem Portugal desde o início do século XXI até à data atual.

The awareness of environmental problems, caused by CO2 emissions, have led the scientific community to seek more sustainable solutions, from both environmental and economical perspectives. Regarding concrete, this goal can be reached through the use of low binder concrete (LBC), consisting of partially replacing Portland cement by additions and increasing the packing density.This paper presents a research conducted to analyse the viability of using LBC in reinforced concrete (RC) structures, namely by studying the bond behaviour between LBC and reinforcing bars (rebars). With this aim, an experimental program including monotonic pull-out tests to assess the influence of concrete

Aiming at reducing the environmental impact of structural concrete, the authors conducted a study to analyse the viability of using low binder concrete (LBC) in reinforced concrete (RC) structures. The study focused on the bond behaviour between LBC and the reinforcing bars (rebars) and is presented ina companion paper. Afterwards, with the goal of further improving the eco-efficiency of LBC, the authors studied the possibility of partially replacing natural aggregates by recycled aggregates from construction and demolition waste (CDW), giving rise to what they called a low cement recycled aggregate concrete (LCRAC).This paper presents a research study conducted to analyse the viability of using LCRAC in RC structures, namely by studying the bond behaviour between LCRAC and reinforcing bars. Similarly to the first study, an experimental program including monotonic pull-out tests was set, this time with the aim of assessing the influence of replacing natural aggregates by recycled aggregates from CDW on the bond behaviour between LCRAC and rebars. Additionally, concrete

The evaluation of the mechanical behaviour of timber beams or glued laminated timber lamellas in-service are generally a difficult task due to the different sources of uncertainty involved (small knowledge about the initial quality of timber, small samples, models uncertainty, human errors). The use of statistical methods that can incorporate part of the uncertainty are probably a suitable way to ensure that the predictions made could provide a reliable prediction of the desired property.In most situations while performing in situ assessment of timber structures, the application of non or semi-destructive testing (NDT or SDT) methods relies on regression linear models showing no-ticeable different coefficients of determination. Another source of uncertainty happens when mak-ing in-situ testing relying on the application of existing regression models to timber members with-out being sure about the wood species or the origin of the wood species. Can these models be used when it is commonly accepted that knowledge on timber

Most European wood species are rapidly and severely degraded in termite-infested areas and the marine environment. There is a need for new solutions, especially in the marine environment, since we lack wood preservatives approved for marine applications in Europe. Several wood modification systems show high resistance against both marine borers and subterranean termites. However, the existing commercialised methods of wood modification are costly. Therefore, a new, low cost and non-toxic wood modification system from inexpensive and readily-available feedstock chemicals have been used in this study. The treatment of wood with a combination of sorbitol and citric acid (PS-modification) showed good resistance against wood borers in the marine environment after one season and against subterranean termites in the laboratory after eight weeks. Future results from the ongoing field tests in the marine environment will reveal the long-term performance of PS-treated wood. The low termite survival rate in the non-choice test already in the first week of testing indicate a mode of action which is not comparable with other wood modification treatments.

The update of timber members

Glued Laminated Timber (GLT) structures are a considerable part of the existing timber buildingstock and, especially for large structures their safety and serviceability evaluation is required,given the high risk of human losses if this type of structures collapse. The available tools are limitedand often present high levels of uncertainty, supporting the need of further studies regarding insituprocedures that may be used to acquire information about the expected mechanical behaviourof GLT members.The present work aims to develop a probabilistic framework procedure to assess the behaviour ofGLT beams. Twenty GLT beams (class GL24h) were produced using Norway spruce wood andtested at different scales. Each beam was composed of five parallel lamellas comprising each onea lamella that was previously tested in bending.The predicted bending strength of the GLT beams was based on a weak zone model used for thelamellas, where strength properties were reduced due to the presence of knots. Each lamella wasrandomly assigned pairs of density and modulus of elasticity values based on a prior experimentalcampaign database. Bending modulus of elasticity was also used as input for a regression equationto assign bending strength values to the lamellas. The knots were also randomly generated. MonteCarlo simulations were used to incorporate the random parameters into the model. For validation,the simulations

Recent documents on assessment of existing timber structures confirms on-site visual strength grade as a starting point for obtaining conservative predictions of timber members reference properties (density, bending strength and modulus of elasticity). This procedure although crucial is limited and complex given the frequent onsite arduous conditions and the high level of subjectivity (based on expert beliefs) associated to visual grading (material variability; weak correlation between features and timber mechanical properties; and often uncertainty about wood species and its origin). To get a more accurate prediction a detail survey (second step) should provide an upgrade of the first predictions. Getting more reliable information based on looking more closely into the critical members and analysing the real stress applied (column or beam) and location of defects related to stress is appointed as a possible solution. The question remains about the tools available for performing such upgrade since modern visual strength grading are based on heuristic techniques which are only known by the laboratories involved in the development of a particular standard. How to make the upgrade and also how to make the fusion of opinions expressed by the different experts or to deal with their insecurity in order to provide a reliable information for structural assessment based on different approaches is a challenge. The present paper intends to contribute to this discussion by testing the possibility of using the principles of the theory of evidence. This theory is discussed as a tool for making the fusion of all data provided by experts. An example of application to twenty beams is carried out and the results discussed taking into consideration the need to sustain the optimal decision about the quality of each timber member.

Assessment of timber members on-site depends on the identification of wood species and consequentselection and application of a proper visual strength grading standard. When wood speciesare not identified or limits exists in that correct identification the interpretation of results fromnon or semi-destructive testing methods in-situ can be affected. Wood species identification iseven more important given the high variability of wood, the possible effect of origin and ageingeffects given a load and moisture-history unknown at the time of inspection are all factors thatneeds to be addressed.The present paper exemplifies the importance of starting from a proper identification of woodspecies to combine results from SDT and provide insight and substantiated information to supportthe design values to be used in a structural analysis. Timber members from a structures withmore than 200 years in service were tested. Wood samples for identification, wood cores for densityand tensile test pieces were collected.The results demonstrate that the combination of information from different sources can provide asafer and more reliable assessment of timber members in service. The results also showed theimportance of knowing the wood species in order to ensure a proper analysis of the data collected.

A avaliação das propriedades de referência (massa volúmica, resistência à flexão e módulo de elasticidade) a considerar para elementos estruturais de madeira em serviço é um processo complexo, mas essencial para a realização da avaliação de uma estrutura quantos aos estados limites. A atribuição destas propriedades inicia-se pela identificação da espécie de madeira e consequente escolha e aplicação de uma norma de classificação visual de elementos de madeira para fins estruturais. Este procedimento, embora subjetivo, permite (uma vez aplicado de forma correta) a obtenção de valores para as propriedades da madeira que levam a uma análise muito conservadora. Isto resulta, por vezes, na recomendação de ações de reforço significativo da estrutura, ou mesmo da sua demolição, quando esta, e para o mesmo uso, não apresenta sinais de dano ao fim de mais de 50 anos em serviço.No presente artigo pretende-se avaliar o possível aumento de fiabilidade da avaliação de elementos de madeira em função do ajuste das propriedades físicas e mecânicas da madeira face ao resultado de ensaios não e semi-destrutivos e da integração desta informação com a obtida por meios visuais, recorrendo a métodos Bayesianos. O comportamento das vigas é simulado por meio de elementos finitos e adotando uma visão dos elementos como constituídos por zonas de madeira limpa e zonas com defeitos (zonas com desvio pronunciado na orientação das fibras devido à existência de nós de tamanho significativo). A incerteza devida à variabilidade da madeira e aos métodos e modelos é incorporada nos resultados através da utilização do método de Monte Carlo. O estudo compreende 33 vigas de pinho bravo de diferentes dimensões, tendo sido analisadas segundo a NP 4305, com recurso a ondas de choque e remoção de carotes. Com este estudo pretende-se avaliar a possibilidade de explorar melhor as capacidades resistentes da madeira através da aplicação deste tipo de análises à avaliação da segurança de estruturas de madeira em serviço.

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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

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.

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

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

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

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.

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.

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.

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.

O presente trabalho apresenta um projecto de Norma Portuguesa relativo ao ensaio de dureza Vickers (HV0,2 a HV5 exclusive) de materiais 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, a fim de actualizar as Normas Portuguesas existentes neste domínio.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.

O presente trabalho apresenta um projecto de versão portuguesa da Norma Europeia EN 10002-1, 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, a fim de actualizar as Normas Portuguesas existentes neste domínio.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.

O presente trabalho consiste no relatório de uma missão a Paris do signatário, na sua qualidade de coordenador da Normalização Nacional no domínio dos "Ensaios mecânicos, físicos e não-destrutivos de materiais metálicos", a fim de representar Portugal numa reunião do ECISS/TC 1a "Ensaios mecânicos e físicos de aços", encarregado dos trabalhos de Normalização Europeia neste domínio.

O presente trabalho pretende mostrar as possibilidades fornecidas pela utilização de um método de simulação no estudo da homogeneidade da fiabilidade, oferecida pelas curvas de encurvadura de colunas, de diferentes regulamentos de estruturas de aço.Através de um modelo geometricamente não linear, de que se faz uma breve apresentação e se descrevem alguns exemplos de aplicação, é feito o estudo da carga crítica de encurvadura de um perfil IPE 120, segundo o eixo de maior inércia. Os resultados apresentados referem-se a cerca de 1000 colunas diferentes, obtidas através de um método de simulação do tipo Monte-Carlo, para as quais se efectua a comparação entre os valores da carga crítica obtidos e os fornecidos por vários regulamentos, bem como a análise da homogeneidade da fiabilidade conferida pelos mesmos regulamentos em função das respectivas esbeltezas.

O presente trabalho apresenta um projecto de Norma Portuguesa com o título

O presente trabalho apresenta um projecto de Norma Portuguesa com o título

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