Publicações

This study evaluated the durability of three innovative multilayer insulation systems incorporating thermal mortars with EPS aggregates and silica aerogel granules after hygrothermal accelerated aging and one year of natural aging at an urban site in Portugal. The loss of performance was assessed after the accelerated aging and every three months of natural aging using non-destructive testing. Chemical-morphological analyses were alsocarried out prior to and after accelerated and natural aging. Results obtained after accelerated and natural aging were compared, thus contributing towards a deeper understanding of possible synergistic effects of several degradation agents and mechanisms on the long-term durability of multilayer insulation systems. The Coffin-Manson equation showed that the accelerated aging procedure (~13 days of heat/rain cycles and 5 days of heat/cold cycles) adopted herein corresponds to approximately 11 years of natural aging in typical urban conditions. The results show a significant increase in capillary water absorption and drying capacity after aging.Extensive surface microcracking was observed after accelerated aging and after 3 months of natural aging, especially in the systems facing North. Traces of biological growth were detected on both the artificially and naturally aged systems, whereas aesthetic alterations were more pronounced in North-oriented specimens after 3 months of exposure, with significantly lower surface gloss and a darker tone. On the other hand, color change cannot be detected in the artificially aged systems (

The internal structures and the hygroscopicity of bio-based boards consisting of giantreed (Arundo donax L.) and hazelnut shells as bio-aggregates, and a sodium silicate solution asthe adhesive, were investigated. The aim was to evaluate the influence of each material (the bio-aggregates and adhesive) and their distributions in the boards on the final performance. By carrying out X-ray computed tomography, the internal structures and the porosities of the boards were determined, allowing important considerations of their hygroscopicity. The voids

ETICS are multilayer building solutions applied to the building external walls to provide animproved thermal performance to the building envelope. However, several questions have beenraised concerning the durability of ETICS, namely related to biological colonisation phenomena.Considering the high susceptibility of ETICS to bio-colonisation, the following research questions arise: (i) what is the impact of surface temperature (ST) and surface relative humidity (SRH)fuctuation on mould growth in ETICS facades? (ii) is it possible to predict mould growth onETICS under fuctuating conditions considering favourable and unfavourable growth conditions?This study aims to investigate the infuence of the hygrothermal behaviour of five different ETICS(with thermal mortars and insulation boards) on mould growth. ETICS were exposed for one yearat an urban site in Lisbon, Portugal, facing North, during which the ST and the SRH weremonitored. Concurrently, numerical simulations were performed to evaluate the hygrothermalbehaviour of the ETICS. Three theoretical indices were applied, using numerically and experimmentally obtained values of ST and SRH as input to provide an indication of the risk of mould growth. The results were complemented and validated by assessing the bio-colonisation, water performance and aesthetic properties of the ETICS. Index 1 (percentage of time with SRH

The introduction of stored product insect pests to new areas is facilitated by food trade among countries, and effective detection and monitoring programs are crucial for food security. The khapra beetle, Trogoderma granarium Everts is one of the most destructive insect species. In Portugal, T. granarium has been detected in 1988. However, no new data has been added to this information since that date. Floor traps with pheromones specific to T. granarium were used and placed inside ports, mills, and storage facilities, including warehouses and silos, between June and September in 2017, 2019, 2021, and 2022.Previous results from other sampling programs conducted between 2002 and 2008 are also referred here to add more evidence for the presence or absence of T. granarium in Portugal. Here, various types of traps, including some generalists and others with pheromones (such as T. granarium), were used. The collected insects were identified to species, or genus.Surveys conducted identified approximately 40 insect species that are associated with stored products, in a total of 23.725 insects, and among them, the weevils belonging to the genus Sitophilus C.J.Schoenherr have been recognized as the main pests that affects stored cereals. Regarding the surveys made between 2017 and 2022 and previous surveys done in Portugal (between 2002 and 2008; n = 26.719 insects identified), no T. granarium individuals were detected in any of the entomological samples, and only a few Dermestidae specimens were found across all surveys, one of them belonging to the same genus, identified as Trogoderma inclusum LeConte. With the predicted changes in climate, there is a risk of introducing T. granarium and other destructive insect pests that could displace itophilus weevils as the key stored products pest in Portugal. Therefore, it is crucial to monitor and implement measures to prevent the spread of invasive pests for effective pest management and food security purposes, using proper trapping methods and accurate and rapid identification tools.

Arundo donax (giant reed or giant cane) is a widely available, perennial, invasive, non-food crop, present worldwide and employed for several uses, including building practices. Considering the increasing demand for sustainable building materials, A. donax can be an eficient solution. This study investigated its properties as a bio-aggregate mixed with a sodium silicate solution as an adhesive. A horizontal analysis that provided a general characterization of the composite was carried out. The results showed that the A. donax-based composite had anapparent density of 517 kg/m3 , thermal conductivity of 0.128 W/(m.K), and high hygroscopicity, with a moisture buffering value of 4.33 g/(m2 %RH), property that could be both an advantage for indoor comfort and a drawback. The uncommon sound absorption behaviour can be comparable to granular materials, with the highest sound absorption coeficient values,

Arundo donax (giant reed or giant cane) is a widely available, perennial, invasive, non-food crop, present worldwide and employed for several uses, including building practices. Considering the increasing demand for sustainable building materials, A. donax can be an efficient solution. This study investigated its properties as a bio-aggregate mixed with a sodium silicate solution as an adhesive. A horizontal analysis that provided a general characterization of the composite was carried out. The results showed that the A. donax-based composite had an apparent density of 517 kg/m3, thermal conductivity of 0.128 W/(m.K), and high hygroscopicity, with a moisture buffering value of 4.33 g/(m2 %RH), property that could be both an advantage for indoor comfort and a drawback. The uncommon sound absorption behaviour can be comparable to granular materials, with the highest sound absorption coefficient values,

The search for innovative and sustainable solutions to improve the energy efficiencyof the construction industry has been a hot topic for researchers due to the tremendous impactof insulator materials in the thermal comfort of buildings. In the present work, an innovativelightweight composite material with thermal insulation properties was developed, for the firsttime, by using cardoon particles and polyurethane. The formulation of the composite materialwas optimized in terms of cardoon fraction and the polyol/isocyanate ratio, to achieve the bestcompromise between internal bond (IB) strength and thickness swelling (TS). The best performing composite was PU75-CP45, with 45 wt% of cardoon particles and 75% of isocyanate, achieving an IB of 0.41 MPa and a TS of 5.3%. Regarding insulation properties, the PU75-CP45 composite material exhibits a promising performance when compared to conventional construction industry materials by tuning its thickness. Additionally, the composite material presented very low emissions of volatile organic compounds and formaldehyde (bellow to legislation levels) and high resistance to biological degradation

External Thermal Insulation Composite Systems (ETICS) are frequently used to enhance the energy efficiency of the built environment. However, stains of presumable biological nature are often detected shortly after application, causing cladding defacement and altering the building aesthetics. To address which microbiota could contribute to these biodeterioration related color/aesthetic anomalies, samples collected from stains detected on the surface of building facades with ETICS in three residential sites in Lisbon, Portugal, were analyzed throughmicrobiological culture-dependent technique and culture-independent amplicon DNA high throughput sequencing taxonomic profiling. The obtained data provided a comprehensive description of microbial communities assigned to diverse taxa of the major microbial groups of heterotrophic bacteria, fungi, cyanobacteria, and microalgae (through DNA plastid detection) in the sampled stains. Based on that, we propose that new microorganisms could be added to the list of bio-susceptibility testing organisms in ETICS. Furthermore, microbiota diversity depended more on facade location and cardinal orientation than on ETICS material composition. Overall, this study reveals the unique microbial communities of color/aesthetic biodeterioration stains in ETICS facades, unlike those of other surfaces, and the associated environmental dynamics.

Laboratory tests were carried out to evaluate the feasibility of producing boards or coating panels with good hygrothermal performance by using different agro-industrial wastes (grape and olive press wastes, hazelnut shells, spent coffee and pine) and adhesives (gypsum-based binder, sodium silicate solution and starch-based glue). Hygrothermal properties and resistance to mould growth, including the effect of citric acid, were evaluated. The results highlighted the benefits and drawbacks of each adhesive: the binder seems more adequate to produce bio-based plastering mortars than boards; the other adhesives seem efficient solutions to produce boards with good hygrothermal properties; for the natural glue the bio-susceptibility needs improvement.

Traditional carpentry joints can be found worldwide in many timber truss structures connectingrafter and tie beam. One failure mode of this connection result from shear in the tie beam beyond the notch either due to bad design or deterioration. In this article, the reduction in shear strength of Single Step Joints (SSJ) resulting from biological attack by anobiids was analysed. For this purpose, tests were carried out in non-degraded scots pine (Pinus sylvestris L.) specimens (reference) and compared to artificially degraded specimens with three different levels of degradation. The reduction of shear resistance was analysed in relation to the density of holes drilled during the degradation simulation, the loss of mass, and the reduction of the hearresistant area. At lower degradation levels, no significant reduction in shear strength was observed. On the other hand, the linear regression shows a trend of resistance reduction with increasing degradation. Despite the relatively low coefficient of determination (r2 = 0.25), the parameterthat best correlated with the residual strength was the reduction in the shear-resistant area.

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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