A utilização da madeira laminada colada (MLC) é uma alternativa viável para o aproveitamento de todo o potencial da madeira, apresentando uma série de vantagens. A ligação entre as lâminas, no entanto, tem papel fundamental para a boa qualidade de peças de MLC. Portanto, para um bom desempenho de estruturas de MLC, é fundamental a escolha de um adesivo com boa resistência mecânica e resistência à ação do intemperismo. Os adesivos comumente utilizados, além de terem alto custo, que chega a 60% do custo total da MLC, contêm solventes que são nocivos à saúde, além de terem coloração escura, o que mancha a madeira. O custo baixo é primordial no sentido de tornar esse material mais viável e competitivo quando comparado com outros materiais. Assim, esse trabalho teve como objetivo verificar a capacidade de carga ao cisalhamento no plano de cola de corpos de prova preparados com um adesivo sem solvente e contribuir para a melhoria de eficiência de vigas laminadas coladas. Foram verificados os efeitos da pressão de colagem (1,25; 2,50 e 5,00 MPa), da temperatura (27, 60 e 90°C) e do tempo de cura do adesivo (7 e 10 dias) na tensão no limite de resistência ao cisalhamento. A dose de adesivo utilizada foi de 200 g/m2. Numa segunda etapa foram obtidas a massa específica e a umidade das amostras já ensaiadas ao cisalhamento a fim de explicar a variabilidade dos resultados encontrados. A madeira utilizada para a confecção das peças foi o Eucalyptus grandis por ser uma espécie de grande potencial para usos múltiplos e porque suas propriedades físicomecânicas o tornam adequado também para fim estrutural. Concluiu-se que a temperatura de 90°C possibilitou os melhores valores de tensão de cisalhamento. A pressão de colagem e o tempo de cura do adesivo não influenciaram nessa importante propriedade mecânica. / The use of glu-lam is a viable alternative for exploitation of all wood potential presenting a series of advantages. The linking between layers however has a basic paper in glu-lam good quality. Therefore for a good performance of glu-lam structures it is fundamental the choice of an adhesive which has a great mechanics resistance and also resistance to the weather action. The adhesives usually used having high cost, that arrives 60% of glu-lam total cost beyond contain solvent that are harmful to health, having dark coloration what changes the wood natural color. Low cost is primordial to become this material more viable and competitive if compared with another materials. Thus, this search had as objective to verify the load capacity applied in the samples in shear strength test right in the glued surface and also contributing for efficiency improvement of beam-glu-lam. The glue used to prepare the samples was free of solvent. It were verified the effect of gluing pressure (1,25; 2,50 e 5,00 MPa), temperature (27, 60 e 90°C) and the adhesive time of cure (7 and 10 days)in the shear strength. The adhesive dose applied in the layers was 200g/cm2.In a second research step it were obtained the specific gravity and moisture content from the samples which were already tested to explain the variability that was observed. It was utilized Eucalyptus grandis wood for being a specie of enormous potential for multi purpose and because its physical and mechanical properties make it. Highest values of shear strength were obtained at the temperature of 90°C. The glue pressure and the adhesive curing time have no relevant influence on this important mechanical properties.

A utilização da madeira laminada colada (MLC) é uma alternativa viável para o aproveitamento de todo o potencial da madeira, apresentando uma série de vantagens. A ligação entre as lâminas, no entanto, tem papel fundamental para a boa qualidade de peças de MLC. Portanto, para um bom desempenho de estruturas de MLC, é fundamental a escolha de um adesivo com boa resistência mecânica e resistência à ação do intemperismo. Os adesivos comumente utilizados, além de terem alto custo, que chega a 60% do custo total da MLC, contêm solventes que são nocivos à saúde, além de terem coloração escura, o que mancha a madeira. O custo baixo é primordial no sentido de tornar esse material mais viável e competitivo quando comparado com outros materiais. Assim, esse trabalho teve como objetivo verificar a capacidade de carga ao cisalhamento no plano de cola de corpos de prova preparados com um adesivo sem solvente e contribuir para a melhoria de eficiência de vigas laminadas coladas. Foram verificados os efeitos da pressão de colagem (1,25; 2,50 e 5,00 MPa), da temperatura (27, 60 e 90°C) e do tempo de cura do adesivo (7 e 10 dias) na tensão no limite de resistência ao cisalhamento. A dose de adesivo utilizada foi de 200 g/m2. Numa segunda etapa foram obtidas a massa específica e a umidade das amostras já ensaiadas ao cisalhamento a fim de explicar a variabilidade dos resultados encontrados. A madeira utilizada para a confecção das peças foi o Eucalyptus grandis por ser uma espécie de grande potencial para usos múltiplos e porque suas propriedades físicomecânicas o tornam adequado também para fim estrutural. Concluiu-se que a temperatura de 90°C possibilitou os melhores valores de tensão de cisalhamento. A pressão de colagem e o tempo de cura do adesivo não influenciaram nessa importante propriedade mecânica. / The use of glu-lam is a viable alternative for exploitation of all wood potential presenting a series of advantages. The linking between layers however has a basic paper in glu-lam good quality. Therefore for a good performance of glu-lam structures it is fundamental the choice of an adhesive which has a great mechanics resistance and also resistance to the weather action. The adhesives usually used having high cost, that arrives 60% of glu-lam total cost beyond contain solvent that are harmful to health, having dark coloration what changes the wood natural color. Low cost is primordial to become this material more viable and competitive if compared with another materials. Thus, this search had as objective to verify the load capacity applied in the samples in shear strength test right in the glued surface and also contributing for efficiency improvement of beam-glu-lam. The glue used to prepare the samples was free of solvent. It were verified the effect of gluing pressure (1,25; 2,50 e 5,00 MPa), temperature (27, 60 e 90°C) and the adhesive time of cure (7 and 10 days)in the shear strength. The adhesive dose applied in the layers was 200g/cm2.In a second research step it were obtained the specific gravity and moisture content from the samples which were already tested to explain the variability that was observed. It was utilized Eucalyptus grandis wood for being a specie of enormous potential for multi purpose and because its physical and mechanical properties make it. Highest values of shear strength were obtained at the temperature of 90°C. The glue pressure and the adhesive curing time have no relevant influence on this important mechanical properties.

This research was conducted to discover how the U.S. building construction and forest products sectors could benefit from the development of tall, cross-laminated (CLT) and mass timber buildings. Barriers that may restrict such development were also investigated. The primary benefits were discovered to be eco-performance and job creation. Code restrictions and material performance misconceptions were found to be the largest obstacles. Case studies of Treet, Tamedia, and the WIDC were conducted to demonstrate the benefits of tall wood buildings and the various paths around potential barriers. Opportunities for tall wood buildings in the U.S. are also discussed. This research discovered that a tall wood movement is gathering momentum in the U.S. To fully realize this potential, accurate information regarding the use of wood and the performance capacities of mass timber systems needs to be disseminated. Co-operation between academia and industry will also be necessary.

Joints are critical parts of timber structures, transmitting static and dynamic forces between structural members. The ultimate behavior of e.g. a building depends strongly on the structural configuration and the capacity of its joints. The complete collapse of a building or other less extensive accidents that may occur usually start as a local failure inside or in the vicinity of a joint. Such serious failures have recently occurred in the Nordic countries. Especially the collapses of two large glued-laminated timber (glulam) structures clearly indicate the need of an improved joint design. The trend toward larger and more complex structures even further increases the importance of a safer design of the joints. One aim of this partly experimentally and partly numerically based work has been to investigate if the short term capacity of steel-timber dowel joints loaded parallel to the grain is affected by an initial drying exposure. The experimental results showed that the load-bearing capacity of the joints is indeed reduced by such moisture changes. Moisture induced stresses was mentioned to be the explanation. The key point is that the climates chosen in the present work (20°C / 65% RH and 20°C / 20% RH) are equivalent to service class 1 according to EC5 (Eurocode 5 2004). Thus, EC5 predicts no decrease in load-bearing capacity, in relation to the standard climate used during testing. A decrease in load-bearing capacity in the range of 5-20%, which was found in the present work, is of course not negligible and, therefore, there could be a need to introduce the effect of drying in design codes. Because similar results were also observed for a double-tapered glulam beam, further work should consider timber structures in general. Two numerical methods in order to predict the capacity of multiple steel-timber dowel joints loaded parallel to the grain were tested in the thesis. For the first method, where fracture mechanics (LEFM) concepts were implemented, a good correlation with the experimental results was seen. Also for the second method, where the capacity for a single dowel-type joint as given in EC5 was used as a failure criterion, a good correlation to traditional EC5 calculations of multiple dowel-type joints was seen. One advantage of using numerical methods in design is that the capacity of the joint can be calculated also for cases when the dowels are placed in more complex patterns. From both a structural and an architectural point of view this can be very important. In addition, such numerical methods are effective tools for the structural engineer when considering complicated loading situations in joints, i.e. eccentric loading giving moments in the joint.