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ResumoO objetivo do trabalho foi avaliar a resistência biológica de moirões de Corymbia torelliana e Eucalyptus grandis x Eucalyptus urophylla, tratados com CCA-C, ao cupim Nasutitermes corniger em testes de laboratório. Para o tratamento dos moirões empregou-se o processo de célula cheia (Bethell). Os moirões tinham 2,20 metros de comprimento e classes diamétricas de 8 a 10; 10 a 12 e 12 a 14 cm. Foram sorteados oito moirões por classe e espécie florestal, e seis foram tratados e dois não tratados (controle). Foi cortado um disco de 2,0 cm de espessura, a 0,50 m da base de cada moirão (não tratado), para avaliar a massa específica básica e as porcentagens de cerne e alburno e, a penetração de cobre (moirão tratado). De cada disco (moirão tratado) foram retiradas quatro amostras da periferia até 1,5 cm (posição 1) e de 1,5 a 3,0 cm (posição 2) para avaliar a retenção e o grau de deterioração provocado nos moirões pelo cupim N. corniger. Foram realizados ensaios de alimentação forçada e de preferência alimentar. As maiores perdas de massa nos ensaios de alimentação forçada e de preferência alimentar foram para a madeira de C. torelliana. Para as madeiras tratadas os cupins sobreviveram 13 e 9 dias, para o C. torelliana e E. grandis x E. urophylla, respectivamente. Os melhores resultados de resistência biológica foram encontrados para a madeira tratada de E. grandis x E. urophylla em ambos os ensaios. Palavras-chave: Ensaios biológicos, moirões, Corymbia torelliana, Eucalyptus grandis x Eucalyptus urophylla. AbstractThis work aimed to evaluate the biological resistance of Corymbia torelliana and Eucalyptus grandis x Eucalyptus urophylla wood treated with CCA-C, against the termite Nasutitermes corniger in laboratory tests. For the treatment of fence posts the full-cell process (Bethell) was employed. The fence posts measured 2.20 meters in length and diametrical classes were of 8 to 10; 10 to 12 and 12 to 14 cm. Thus eight fence posts per class and forest species were selected, and six were treated and two untreated (control). A disk of 2.0 cm thickness at .50 m from the base was cut from each fence post (untreated), to evaluate the basic density and the heartwood and sapwood percentages and the penetration of copper (treated fence posts). Of each disk (treated fence posts) four samples were obtained from the periphery to 1.5 cm (position 1) and 1.5 to 3.0 cm (position 2) to evaluate the retention and degree of deterioration caused by N. corniger termite in the fence post. Tests were carried out with no choice feeding and choice feeding tests. The greatest mass losses in the no choice feeding and choice feeding tests were those with C. torelliana wood. In treated wood termites survived 13 and 9 days to the C. torelliana and E. grandis x E. urophylla woods, respectively. The best results of biological resistance to termites were found for the E. grandis x E. urophylla treated wood in both tests.

In Brazil, studies about pedestrian-induced vibrations on footbridges have been carried out since the early 1990s, for concrete and steel footbridges. However, there is no record of such studies and the Brazilian Standard NBR 7190 (1997) for the design of timber structures only presents design requirements for static loads, in the case of timber footbridges. Therefore, this paper aims to general theoretical analysis, numerical and experimental simply-supported beams timber footbridges, with a view to proposing recommendations for projects related to human comfort in these structures. This study was developed from the study of standard guidelines and criteria suggested by several authors, the theoretical analysis of footbridges design according to the criteria of the NBR 7190 (1997), numerical models using finite element and experimental tests on reduced models. Among the conclusions reached, it is emphasized that the formulation of Euler-Bernoulli is suitable for calculating the first natural frequency in vertical and lateral directions simply-supported beams timber footbridges; however, special attention should be given to the evaluation of lateral bending stiffness. Finally, we have suggested a proposal serviceability limit state verification due to pedestrian-induced vibrations on simply-supported beams timber footbridges, concerning the calculation of frequencies and accelerations to be included in a future review of the Brazilian Standard for the design of timber structures.

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27The main goal of this study was to analyze glue line on eucalyptus wood. In order to do 28 that, thickness of main and secondary glue lines were measured as well their interaction 29 with apparent density of elements glued with resorcinol-formaldehyde (RF) and castor 30 polyurethane (CP) adhesives. Anatomical wood characterization of Eucalyptus grandis 31 × Eucalyptus urophylla was performed by correlating glue line thickness. According to 32 normative instruction, specimens were produced for delamination tests. The experiment 33 was conducted in a completely random 2 × 2 design factorial scheme (two classes of 34 apparent density and two adhesives). Pearson correlation (t < 0.01) was performed 35 among variables. It was found that there was adhesive penetration into wood pots and 36 rays. Glue line thickness was higher in woods with density higher than 0.58 g cm -3 glued 37 with RF adhesive. There was low correlation among density, vessel diameter, main and 38 secondary glue lines (t < 0.01). 39 40 Keywords: apparent density; resorcinol-formaldehyde; castor polyurethane; laminated 41 wood; delamination 42 43 Introduction 44Glued laminated timber (Glulam) is a structural product obtained by gluing 45 pieces of timber with fibers parallel to each other [1]. The market still needs to know 46 more information about the mechanical resistance of this product; for that reason, to 47 understand how glulam will work it is important to evaluate the behavior of some 48 variables, such as, apparent density and timber glued with adhesive. 49Wood density provides information to support methods that should be adopted 50 during the gluing process. By its determination, it is possible to correlate adhesion 3 51 resistance with anatomic elements. Proportion of empty spaces combined with 52 dimensions and arrangement of cellular elements have influence on adhesive's mobility 53 and penetration into timber structure as well in the resistance of glue line to 54 delamination [2, 3, 4, 5,6, 34]. When low density (higher frequency and vessel 55 diameters, with high and wide radii), it may allow excessive penetration of adhesive, if it 56 does not present an ideal viscosity and formation of ravenous glue line [7, 8]. 57When species are anatomically unfavorable for gluing, there will be low 58 adhesive penetration and formation of a thick glue line [8, 9]. Both types of glue lines 59 are undesirable, because they reduce mechanical strength of glued joints causing 60 separation of adjacent layers. Variations on adhesive viscosity can correct this problem 61 [3]. 62 Physico-chemical adhesion phenomenon predicts an interaction mechanism 63 between solid surfaces glued by adhesive and the capacity of holding other materials 64 together [10]. Adhesives are used to join elements by flowing and filling empty spaces 65 between them. Thus, they can reduce distances and create interactions among glued 66 elements [11]. 67 It is important to understand the interaction between wood and adhesive, because 68 it helps to evaluate glueing quality [7],...