Publicações

Over the past few decades, species distribution modelling has been increasingly used tomonitor invasive species. Studies herein propose to use Cellular Automata (CA), not only to modelthe distribution of a potentially invasive species but also to infer the potential of the method in riskprediction of Reticulitermes grassei infestation. The test area was mainland Portugal, for which anavailable presence-only dataset was used. This is a typical dataset type, resulting from eitherdistribution studies or infestation reports. Subterranean termite urban distributions in Portugalfrom 1970 to 2001 were simulated, and the results were compared with known records from both2001 (the publication date of the distribution models for R. grassei in Portugal) and 2020. Thereported model was able to predict the widespread presence of R. grassei, showing its potential as aviable prediction tool for R. grassei infestation risk in wooden structures, providing the collection ofappropriate variables. Such a robust simulation tool can prove to be highly valuable in the decisionmakingprocess concerning pest management.

The present study aims at evaluating the impact of anobiid damage on pine timberelements. Anobiid attack produces a diffuse damage of the elements with a set of tunnels in randomdirections and sizes, thus confusing quantification. Therefore, a method was developed based onX-ray micro-computed tomography (

This article evaluates the relevant properties of cement-bonded particleboards (CBPB)made with a portion of maritime pine (Pinus pinaster) particles replaced with an agricultural waste, banana pseudostem (Musa sp.). The industrial production of CBPB was simulated in the laboratory based on a reference composition defined by a manufacturing company. Test specimens were produced assuming 0%, 25%, 50% and 75% partial replacement of wood particles with banana pseudostem fibres. Some physical properties (bulk density, thermal conductivity, and dimensional stability) and the mould susceptibility of the different variables were assessed. Results show that the thermal conductivity of the boards increased with the banana fibre proportion and ranged between 0.233 W/(m.K) and 0.279 W/(m.K). The bulk density values generally increased with the banana fibre proportion and ranged between 1754

External Thermal Insulation Composite Systems (ETICS) have been extensively used for either new constructions or building facades retrofitting in the last decades. These systems can provide improved thermal performance to the building envelope. However, their long-term durability remains a pervasive concern, with some systems presenting relevant anomalies after few years from their application. The durability assessment of ETICS is defined by the EAD 040083-00-0404 guideline, which stated an accelerated ageing procedure based on the hygrothermal and freeze-thaw behaviour. Nevertheless, further important environmental urban conditions, such as UV radiation and atmospheric pollutants, as well as bio-susceptibility, are not envisaged in the guideline. This paper presents the results of an experimental campaign with the aim of evaluating the durability of the rendering system of several commercially available ETICS exposed to an innovative accelerated ageing procedure, which consists of hygrothermal cycles, UV radiation and air pollutants (SO2) exposure. Physical and chemical-morphological tests were carried out prior and after each ageing cycle in order to evaluate the durability of ETICS. Biological susceptibility to moulds was also assessed. The experimental results showed that both surface hardness and surface gloss decreased after the combined effect of the hygrothermal, UV, and SO2 ageing cycles, whereas an increase of surface roughness was observed. Substantial colour change for all systems after the ageing procedure was observed, confirming aesthetic alteration. Traces of biological growth were detected on the systems after ageing and the contact angle decreased after the hygrothermal cycles, indicating a lower surface hydrophobicity of the systems.

External Thermal Insulation Composite Systems (ETICS) are constructive solutions widely used to increase the thermal insulation in new and retrofitted buildings. However, these systems can present several anomalies due to their constant exposure to weathering agents and anthropic factors. Water is generally the major cause of degradation. Thus, the application of water-repellent products can minimize the appearance of anomalies and increase the durability of the systems. Inthis paper, acrylic-based and siloxane-based hydrophobic products were applied to ETICS, with the aim of assessing the compatibility, effectiveness, and durability of these products. The moisture transport properties and mould susceptibility were assessed through laboratory tests on untreated and treated specimens. The durability of the hydrophobic treatments was also evaluated through artificial aging tests (heat-cold and freeze-thaw cycles). Results show that the protection products generally decreased water absorption, slightly decreased the drying rate, and presented adequatewater vapor permeability. After aging, the products still had reasonable effectiveness and, with one exception, improved the water vapor diffusion of the systems. Additionally, ETICS underwent an alteration in the finishing coat (possible modification of the porosity) due to the aging cycles. No clear linear correlation was found between the contact angle values and water absorption results,evidencing the influence of other factors related to the composition of the water-repellent products.

The majority of thermal modification processes are at temperatures greater than 180

The use of External Thermal Insulation Composite Systems (ETICS) significantly increased in the last decades due to their enhanced thermal properties, low installation cost and ease of application, not only innew constructions but also for thermal retrofitting of building facades. These multilayer rendering systemsare constantly exposed to weathering agents and anthropic factors which can lead to physicalmechanicaland aesthetical anomalies and thus affect their durability. However, possible synergeticeffects among these agents are often neglected by international technical documents on the evaluationof the effectiveness and durability of ETICS. With the aim of filling this gap, moisture transport properties(capillary water absorption, water vapor permeability, water absorption under low pressure, and dryingkinetics), thermal conductivity, mould susceptibility and surface properties (color, gloss, and roughness)of twelve commercially available ETICS were assessed and discussed. Possible links between these factorswere analyzed and ETICS performance parameters were defined. Results demonstrate that a deeperknowledge of the correlation among ETICS properties can effectively contribute to the evaluation ofthe efficiency and long-term durability of these systems.

The introduction of new species in forest management must be undertaken with a degree ofcare, to help prevent the spread of invasive species. However, new species with higher profitability are needed to increase forest products value and the resilience of rural populations. Paulownia tomentosa has an extremely fast growth. The objective and novelty of this work was to study the potential use of young Paulownia trees grown in Portugal by using heat treatment to improve its properties, thereby allowing higher value applications of the wood. The average chemical composition of untreated and heat-treated wood was determined. The extractive content was determined by successive Soxhlet extraction with dichloromethane (DCM), ethanol and water as solvents. The composition of lipophilic extracts was performed by injection in GC-MS with mass detection. Insoluble and soluble lignin, holocellulose and

Samples from the two most common pines grown in Portugal (Pinus pinasterAit) and Spain (Pinus radiata, D. Don) were heat-treatedin industrial facilities in accordance with ThermoWood ®class D. For both species, the variation in surface properties, ofuntreated and heat-treated wood after artificial weathering from 75 to 750 h, is presented. The analysis included the determination of color, roughness,gloss,and wettability before exposure and after each artificial weatheringperiod.Untreatedwoods became darkerfaster, while in heat-treated woods,lightness remained approximately constant until 750 h of artificial weathering. Both untreated and heat-treatedwood becamemore reddish in the beginning of the weathering process,turning greener for longerexposure times. Untreated woods became yellower in the beginning,turning into blueish tones later. Heat-treated wood turned slightly yellower until 750 h of weathering. Gloss decreased for untreated wood with no significant changes in heat-treated wood. Despite the changes, the gloss of both untreated and heat-treated wood convergedto similar values.Roughness increased for both untreated and heat-treated woods. Artificial weatheringincreased the wettability of heat-treated wood.

Samples from the two most common pines grown in Portugal (Pinuspinaster Ait) and Spain (Pinus radiata, D. Don) were heat-treated inindustrial facilities in accordance with ThermoWood ® class D. For bothspecies, the variation in surface properties, of untreated and heat-treatedwood after artificial weathering from 75 to 750 h, is presented. Theanalysis included the determination of color, roughness, gloss, andwettability before exposure and after each artificial weathering period.Untreated woods became darker faster, while in heat-treated woods,lightness remained approximately constant until 750 h of artificialweathering. Both untreated and heat-treated wood became more reddishin the beginning of the weathering process, turning greener for longerexposure times. Untreated woods became yellower in the beginning,turning into blueish tones later. Heat-treated wood turned slightly yelloweruntil 750 h of weathering. Gloss decreased for untreated wood with nosignificant changes in heat-treated wood. Despite the changes, the glossof both untreated and heat-treated wood converged to similar values.Roughness increased for both untreated and heat-treated woods. Artificialweathering increased the wettability of heat-treated wood.

A tensão de cedência à tração dos aços dos varões para betão armado (fy), ou a tensão limiteconvencional de proporcionalidade a 0,2% (f0,2) no caso de esses aços não apresentarem cedência,constitui uma das principais características mecânicas consideradas nos cálculos de verificação dasegurança das estruturas de betão armado.Para cada classe de resistência destes aços, a tensão de cedência pode apresentar variaçõessignificativas, que dependem da composição química do aço, da proveniência dos varões (dofabricante, dos métodos de fabrico utilizados e do respetivo lote de produção), do diâmetro dos varões e dos métodos de ensaio utilizados na sua determinação, por exemplo.O presente artigo apresenta um estudo estatístico da informação sobre os valores de fy (ou de f0,2)obtida pelo LNEC, ao longo das duas últimas décadas, no âmbito do controlo periódico deste tipo deproduto.Com base nos resultados obtidos estabelecem-se comparações entre distribuições estatísticas destacaracterística mecânica, referentes a aços pertencentes a diferentes classes de resistência, e procede-se a uma análise da sua evolução ao longo do tempo e da sua conformidade com as exigências normativas que lhes são aplicáveis.É também apresentada uma comparação entre as distribuições estatísticas dos valores de fy obtidos no âmbito dos ensaios de verificação do produto, realizados pelo fabricante dos varões, e as distribuições estatísticas dos valores de fy obtidos nos ensaios de acompanhamento (controlo externo) realizados pelo LNEC.

A tensão de cedência à tração dos aços dos varões para betão armado (fy), ou a tensão limite convencional de proporcionalidade a 0,2% (f0,2) no caso de esses aços não apresentarem cedência, constitui uma das principais características mecânicas consideradas nos cálculos de verificação da segurança das estruturas de betão armado.Para cada classe de resistência destes aços, a tensão de cedência pode apresentar variações significativas, que dependem da composição química do aço, da proveniência dos varões (do fabricante, dos métodos de fabrico utilizados e do respetivo lote de produção), do diâmetro dos varões e dos métodos de ensaio utilizados na sua determinação, por exemplo.O presente artigo apresenta um estudo estatístico da informação sobre os valores de fy (ou de f0,2) obtida pelo LNEC, ao longo das duas últimas décadas, no âmbito do controlo periódico deste tipo de produto.Com base nos resultados obtidos estabelecem-se comparações entre distribuições estatísticas desta característica mecânica, referentes a aços pertencentes a diferentes classes de resistência, e procede-se a uma análise da sua evolução ao longo do tempo e da sua conformidade com as exigências normativas que lhes são aplicáveis.É também apresentada uma comparação entre as distribuições estatísticas dos valores de fy obtidos no âmbito dos ensaios de verificação do produto, realizados pelo fabricante dos varões, e as distribuições estatísticas dos valores de fy obtidos nos ensaios de acompanhamento (controlo externo) realizados pelo LNEC.

A tensão de rotura à tração dos aços dos cordões utilizados na aplicação de pré-esforço (fp) constitui uma das principais características mecânicas consideradas nos cálculos de verificação da segurança das estruturas de betão pré-esforçado. Esta característica pode apresentar variações significativas, que dependem da composição química do aço, da proveniência dos cordões (do fabricante, dos métodos de fabrico utilizados e do respetivo lote de produção), do diâmetro dos cordões e dos métodos de ensaio utilizados na sua determinação, por exemplo.O presente artigo apresenta um estudo estatístico dos valores da tensão de rotura à tração de cordões de aço da classe de resistência 1860, formados por seis fios do mesmo diâmetro nominal enrolados helicoidalmente em torno de um fio central reto. Os resultados experimentais analisados foram recolhidos pelo LNEC ao longo das duas últimas décadas, no âmbito do controlo periódico deste tipo de produto. Com base nos resultados obtidos estabelecem-se comparações entre as distribuições estatísticas desta característica mecânica, referentes a cordões de aço com seis diâmetros nominais diferentes e com diversas proveniências, bem como entre as suas evoluções ao longo do tempo.

Bridge falsework systems are used to support the formwork during the construction of concrete bridges. Relevant stakeholders often do not consider them as important as permanent structures, and in recent years a high number of accidents involving bridge falsework systems have been reported. In this paper, a survey of the failures of bridge falsework systems since 1970 is presented, including an update to the information already published, covering the period between 1970 and 2012, with new data from the period between 2013 and 2015. The collected data provides useful statistics for risk assessments when considering the potential consequences associated with failures of bridge falsework systems.

Subterranean termites are known as serious pests of wood, having highly efficient lignocellulose degradation ability which largely relies on flagellate protist symbionts present in the hindgut. It is clear that the symbiotic association between lower termites and their hindgut symbionts have advantages for both, since the termites are able to receive an extra energy supply resulting from lignocellulose degradation, while hindgut symbionts have shelter, protection and food, supplied by the termite host. Termite gut microbiota and respective cellulosic activity may be a strategic target for designing molecular-based bio-pesticides for termite control. For such an innovative strategy, the characterization of the flagellate protist symbiotic fauna should be pursued.The effect of different diets on termite flagellate protists community of the lower termite Reticulitermes grassei (Clément), the principal subterranean termite species in Portugal, was investigated. The main objectives of this STSM were to obtain high quality microscopy images of flagellate protists and to assess the correct methodology to perform a transcryptomic analysis of flagellate protists. Termites were collected in Portugal and offered six different diets (natural diet (pieces of the wood from where they were collected), pine wood (Pinus pinaster Aiton), European beech (Fagus sylvatica L.), thermally modified beech (submitted to 180ºC during 4 hours), cellulose (cellulose powder mixed with deionized water) and starving (no source of cellulose offered to the termites) for 14 days. After this trial, termites were evaluated in terms of flagellate protists diversity and abundance and prepared for microscopical and molecular analysis.The results obtained showed clearly that termite flagellate protist communities living inside their hindgut change according with the type of diet. The RNA and DNA extraction techniques experimented, although not as successfully as expected, were a step forward towards the optimization of the methodology to be applied to achieve good quality samples for further analysis. The use of Transmission Electron Microscopy enabled the first visualization of flagellate protists from R. grassei hindgut, allowing the further analysis of their internal physiology, important for their correct identification. The search for new wood treatments and biobased materials must take into consideration their resistance to biological degradation agents, as subterranean termites. On the other hand, further knowledge of the effect of the different products on the symbiotic interactions on the termite gut might lead to interesting developments in future termite control.

In recent years there has been a growing interest in developing news solutions for more ecologic and efficient construction, including natural, renewable and local materials, thus contributing in the search for more efficient, economic and environmentally friendly construction. Several authors have assessed the possibility of using various agricultural sub products or wastes, as part of the effort of the scientific community to find alternative and more ecologic construction materials.Corn cob is an agricultural waste from a very important worldwide crop. Natural glues are made from natural materials, non-mineral, that can be used as such as or after some modifications to achieve the behaviour and performance required. Two examples of these natural glues are casein and wheat flour-based glues that were used in the present study. Boards with different compositions were manufactured having as variables the type of glue, the dimension of the corn cob particles and the features of the pressing process.The tests boards were characterized with physical and mechanical tests, such as thermal conductivity with a ISOMET 2104 and 60 mm diameter contact probe, density based on EN 1602:2013, surface hardness (SH) with a PCE Shore A durometer, surface resistance (SR) with a PROCEQ PT pendular sclerometer, bending behaviour based on EN 12089:2013, compression behaviour based on EN 826:2013 and resilience (R) based on EN 1094-1:2008, with a Zwick Rowell bending equipment with 2 kN and 50 kN load cells (Fig. 1), dynamic modulus of elasticity with a Zeus Resonance Meter equipment (Fif. 5) based on NP EN 14146:2006 and water vapour permeability based on EN 12086:2013.The various boards produced were characterized according to the tests and the ones with the best results were C8_c8 (casein glue, grain size 2,38-4,76 mm, cold pressing for 8 hours), C8_c4 (casein glue, grain size 2.38-4.76 mm, cold pressing for 4 hours), F8_h05 (wheat flour glue, grain size 2.38-4.76 mm, hot pressing for 0,5 hours), FEV8_h0.5 (wheat flour, egg white and vinegar glue, grain size 2.38-4.76 mm, hot pressing for 0,5 hours) and FEVH68_c4 (wheat flour, egg white, vinegar and 6 g of sodium hydroxide glue, grain size 2.38-4-76 mm, cold pressing for 4 hours).

Despite their importance on diverse ecosystems, termites may also be considered severe pests of wood in service, and also as agricultural and forestry pests.Subterranean termites

O presente artigo propõe uma definição para a eficiência da geometria de uma secção em I submetida a flexão composta. Em seguida demonstra-se que, para cada valor da espessura relativa da sua alma, , é possível encontrar, em regime elástico e em regime plástico, um valor específico para a espessura relativa dos seus banzos, , que permite aumentar a eficiência da resistência à flexão da secção. Por fim, são apresentadas representações gráficas dos factores e , referentes às secções em I das principais séries de perfis europeus, que mostram o posicionamento destes factores relativamente às configurações geométricas que optimizam a eficiência da resistência à flexão destes perfis.

This paper proposes a new analytical criterion for the interaction between the resisting bending moment and axial force of steel I-sections bent over one of their main axes, in their plastic limit states, corresponding to the formation of a plastic hinge. The formulation of this criterion, based on an integration of the stress field over the whole cross-section area, took into account the influence ofthe cross-sections root fillets in the transition zones between the cross-section web and each one of itsflanges. Therefore, this new criterion represents a more accurate theoretical solution when comparedto other analytical criteria based on simplifying hypotheses, such as those adopted in some steeldesign codes and standards. Furthermore, it presents the advantages of its simplicity and commonapplicability to both cases of bending over the cross-section strong and weak axis. An applicationexample shows the solving procedure of a design problem by means of this new criterion and by theEurocode 3 rules. Then, a comparative study between the values provided by these two methods ispresented for the most common European, American, British and Japanese I-shapes.

O presente trabalho apresenta um estudo sobre a influência dos troços de concordância, entre a alma e os banzos de secções em I, na sua resistência plástica em flexão composta e em flexão composta desviada. Este estudo baseou-se na aplicação de um novo critério de interacção, proposto pelo autor, que toma em consideração a influência dos troços de concordância e é aplicável à flexão em torno dos eixos de maior inércia ou de menor inércia da secção. Posteriormente, é apresentado um estudo sobre o critério do EC3 para o cálculo dos esforços resistentes em flexão composta desviada, na sequência do qual é proposta uma alteração a este critério que permitirá melhorar os resultados por ele fornecidos.

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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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