Nowadays, timber is widely used in construction industry thanks to its availability and good properties. The use of solid (sawn) timber is not always proper since it is only available up to certain dimensions. Therefore, the so-called Engineered WoodProducts (EWPs) have been introduced to cope with the different design needs of structures. The Glued laminated Timber (glulam) is a type of EWPs that consists of smallsections of timber laminates glued together to form beams and columns. Glulam can be manufactured in almost any size and shape; it can also be tapered or notched. However, notching a beam at its end leads to a stress concentration at the re-entrantcorner of the notch due to the sudden change in the notched beam’s cross section. The concentration of shear and tensile stresses perpendicular to the grain can lead to a catastrophic brittle failure caused by the crack propagation from the notch corner. Crack opening due to tensile stresses perpendicular to grain is the most common failure at the notch corner and it is always taken into design consideration. However,shear component is usually exists and must be also considered in design to guarantee the safety of the structure. Currently, only the normal forces perpendicular to the beam’s axis are considered in the design of the reinforcement in design handbooks. The aim of this thesis was to study the structural behavior of notched glulam beams reinforced by adhered plywood panels and FRP. The carrying capacity of the notched glulam beams at their ends is the main subject of this thesis. In addition, a review of the notched beams design, reinforcements, and analysis theories are included. Experimental series of three point bending tests with notched glulam beams withdifferent configurations of reinforcement was carried out in lab. Deformations and forces were measured both with conventional techniques and with contact-free measurement systems - ARAMIS. On the other hand, a simple model of two dimensional plane stress element has been created of the unreinforced notchedbeam in ABAQUS. The normal and shear stresses were calculated for a horizontalpath of 100 mm in length starting from the notch tip. Afterwards, the mean stresseswere determined for the same path and have been used in calculations. The Mean Stress Approach has been adopted in the hand calculations to calculate the crack length and the failure load according to the ABAQUS model. Accordingly, the failure load was about 40 kN for the unreinforced beams. Also, Eurocode 5 has been used to calculate the failure load which gave a value of 20.2 kN for the unreinforced beams. The average maximum applied load in tests was 30 kN for the unreinforced beams while it reached about two and a half times this value for the CF-reinforced and the plywood-reinforced beams. / Tack vare sina goda egenskaper används trä i byggnadskonstruktioner i allt storeomfattning. Konstruktionsvirke (sågade trävaror) kan dock inte alltid användas pågrund av de begränsade dimensioner som finns tillgängliga. På grund av bl a dettahar ett flertal så kallade engineer wood products (EWP) utvecklats. Limträ är en typav EWP som består av sammanlimmade lameller som bygger upp tvärsnitt i balkareller pelare. Limträ kan tillverkas i nästan godtycklig storlek och form och kan enkeltförses med t ex urtag. Vid urtag i balkändar nära upplag uppstår högaspänningskoncentrationer vid urtagets horn på grund av geometrin. Koncentrationenav normalspänningar och skjuvspänningar kan leda till plötsligt brott på grund avsprickpropagering från urtagets hörn, något som måste tas hänsyn till viddimensionering. Dagens dimensioneringsmetoder är baserade på att man tar hänsyntill enbart normalspänningarna vinkelrät fiberriktningen.Målet med detta arbete har varit att studera beteendet hos limträbalkar med urtag vidupplag som förstärkts med fiberarmering eller plywood. Huvudmålet har varit attbestämma balkarnas bärförmåga, vilket skett genom att genomföra försök med olikakonfigurationer vad gäller förstärkningsmaterial och dess utformning. Vidare harolika dimensioneringsmetoder från litteraturen studerats.Kraft och förskjutning under provningarna uppmättes dels med traditionellamätmetoder, men deformationerna mättes även med beröringsfri metod, ARAMIS.En enkel tvådimensionell finit elementmodell skapades och analyserades i ABAQUSför analys av oförstärkt balk. Normalspänningar och skjuvspänningar beräknades ochmedelspänningarna längs en på förhand definierad sträcka beräknades.Medelspänningskriteriet användes sedan för att uppskatta balkens bärförmåga.Enligt FE-beräkningarna uppskattades bärförmågan för de oförstärkta balkarna till ca40 kN. Provningarna gav ett medelvärde på balkarnas bärförmåga på ca 30 kN,medan de förstärkta balkarna hade en 2,5 gånger högre bärförmåga. Skillnadenmellan FE-beräkningarna och provningarna kan förklaras med den osäkerhet somfinns vad gäller det aktuella trämaterialets egenskaper.Beräkningar enligt Eurokod 5 gav en karakteristisk bärförmåga på 20,2 kN.

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Cross-laminated timber (CLT) is an emerging engineered wood product in North America. Past research effort to establish the behaviour of CLT under extreme loading conditions has focussed CLT slabs with idealized simply-supported boundary conditions. Connections between the wall and the floor systems above and below are critical to fully describing the overall behaviour of CLT structures when subjected to blast loads. The current study investigates the effects of “realistic” boundary conditions on the behaviour of cross-laminated timber walls when subjected to simulated out-of-plane blast loads. The methodology followed in the current research consists of experimental and analytical components. The experimental component was conducted in the Blast Research Laboratory at the University of Ottawa, where shock waves were applied to the specimens. Configurations with seismic detailing were considered, in order to evaluate whether existing structures that have adequate capacities to resist high seismic loads would also be capable of resisting a blast load with reasonable damage. In addition, typical connections used in construction to resist gravity and lateral loads, as well as connections designed specifically to resist a given blast load were investigated. The results indicate that the detailing of the connections appears to significantly affect the behaviour of the CLT slab. Typical detailing for platform construction where long screws connect the floor slab to the wall in end grain performed poorly and experienced brittle failure through splitting in the perpendicular to grain direction in the CLT. Bearing type connections generally behaved well and yielding in the fasteners and/or angles brackets meant that a significant portion of the energy was dissipated there reducing the energy imparted on the CLT slab significantly. Hence less displacement and thereby damage was observed in the slab. The study also concluded that using simplified tools such as single-degree-of-freedom (SDOF) models together with current available material models for CLT is not sufficient to adequately describe the behaviour and estimate the damage. More testing and development of models with higher fidelity are required in order to develop robust tools for the design of CLT element subjected to blast loading.

Timber-concrete composite (TCC) floor systems consist of a bottom layer of wood that is connected to a top layer of concrete using shear connectors. The shear connectors resist slip between the layers, thus allowing wood and concrete develop composite action when subjected to flexure. The objective of this study is to determine the flexural strength and behavior of TCC floor systems that consist of a cross laminated timber wood layer connected to a concrete top layer using hexagonally headed self-tapping screw shear connectors. To accomplish the objective, coupon specimens and full-scale TCC floor panels were tested, and a finite element modelling approach was developed. The coupon tests were used to determine the stiffness of the shear connection and to determine the effect of the screw configuration. The results from the coupon tests indicated that the inclined screw configuration provided the largest shear strength compared to the normal, crossed, and nested screw configurations. Based on the results from the coupon tests, bending and vibration (heel drop) tests were conducted on full-scale panel specimens with an inclined screw configuration and with a strong-axis panel orientation. The results from the full-scale panel tests showed that the flexural stiffness and strength of the TCC floor system was consistent and that the composite floor panels have adequate stiffness to minimize transient floor vibrations that are caused by walking for typical span lengths and typical loading. A finite element model of TCC floor systems was developed to simulate TCC floor systems and calibrated with the test data. The simulated response matched the test response fairly well for partially composite single-span and double-span panels. Additional refinement of the model is needed to better match fully composite panels. The research demonstrated that hexagonal-headed self-tapping screws may be effectively used to connect wood and concrete layers in TCC floor systems.

How can we as design professionals contribute to increase the use of less carbon-intensive materials to build our growing cities? Cities are experiencing a resurgence in population growth and therefore the building industry ought to attend this demand with sustainable solutions. One way of responding to the growing urban population and increase demand for housing as well as to make efficient use of our limited resources is to increase the density in our cities. Since steel and concrete have high material strengths, we currently use either steel, concrete or composites of them to build skyscrapers. Unfortunately, both of these materials have a large carbon footprint. The design community has the challenge to achieve net-zero emissions buildings by the year 2030, and the efforts now should be focused on using less carbon intensive materials, such as timber. While cultures around the world have built with wood for centuries, recent technological innovations, such as Cross Laminated Timber (CLT), is allowing for new applications of wood as the main structural material and the potential to use it for large-scale projects. However, as expected with a new building material some constrains have still to be overcome. For my thesis, I desired to explore this issue through the design of a tall building using mass timber as its main structural material. Engineered timber is here, the future is bright! / Master of Architecture

Cross-Laminated Timber (CLT) combines layers of dimension lumber in alternating grain direction to form a mass timber panel that can be used to create entire wall, floor and roof elements. The viability of CLT as an element to resist lateral forces from racking has been of great interest (Dujic et al. 2004, Blass and Fellmoser 2004, and Moosbrugger et al. 2006). However, most research to date has been conducted on full-scale wall panels connected with proprietary fasteners according to European Test Methods. Little research has focused on non-proprietary connections, including nails, bolts and lag screws. The behavior of CLT full-scale wall panels is dependent upon the individual connection properties including the panel-panel connections between adjoining CLT panels within the wall. The purpose of this research is to evaluate the behavior of three small-scale CLT connection configurations using non-proprietary fasteners. Three different connections -LVL surface spline with lag screws, half-lap joint with lag screws, and butt joint with a steel plate fastened with nails - were tested in both monotonic and cyclic tests. In all, 30 connection tests were conducted, with 15 monotonic test and 15 cyclic tests. Connection strength, stiffness, and ductility were recorded for each connection. Experimental values were compared to National Design Specification for Wood Construction, or NDS (AWC 2012) predictions for connection strength. Nailed steel plate connections yielded much greater loads and behaved in a more ductile manner than did the lag screwed connections. The surface spline and half-lap connections often failed in a catastrophic manner usually due to splitting of the spline and fastener failure. Experimental results were generally lower than predicted by the yield models for the surface spline and steel plate connections. The half-lap connection resulted in higher experimental results than predicted. A discussion of the connection strength for materials with a non-homogeneous grain direction is also included. / Master of Science

Painéis de Cross Laminated Timber (CLT) consistem em um elemento construtivo relativamente novo no cenário da construção civil internacional. No Brasil, a fabricação desta tecnologia iniciou-se há cerca de seis anos. Em razão de sua incipiente utilização em território nacional, não se formou ainda bibliografia consistente a seu respeito, suscitando questionamentos sobre o desempenho dos painéis ao longo da vida útil da edificação. Deve-se ressaltar também que o elemento construtivo estudado consiste em uma inovação, associada à pré-fabricação e a técnicas de fabricação digital, diferenciando-se das tecnologias convencionais com as quais arquitetos e projetistas estão acostumados a projetar. Consequentemente, observam-se frequentes dúvidas não apenas sobre o desempenho dos painéis, mas também associadas a como projetar, de forma eficaz e apropriada, um edifício em CLT. Logo, surge o interesse em aprofundar os estudos acerca da tecnologia, com o intuito de propor, ao final da pesquisa, recomendações para projetos arquitetônicos que visem incorporar painéis de CLT de produção brasileira. Dessa forma, estudou-se tanto o desempenho do elemento construtivo, no que diz respeito à segurança estrutural e à durabilidade, conforme a ABNT NBR 15575:2013, quanto o processo construtivo de edificações em CLT. Para a análise de desempenho mencionada foram realizados os seguintes ensaios laboratoriais: retenção e penetração do produto preservativo na matéria-prima utilizada para a fabricação dos painéis nacionais; impacto de corpo mole, impacto de corpo duro e determinação da resistência do painel às solicitações de peças suspensas; estanqueidade à água; verificação do comportamento do painel exposto à ação de calor e choque térmico; ensaios de delaminação. Ao final, em vista de inconformidades apontadas em alguns ensaios, constatou-se a necessidade de assegurar a qualidade no tratamento da matéria-prima e na colagem das lamelas, de modo a garantir a devida vida útil da edificação. Concluiu-se, também, que o CLT se apresenta, de fato, como uma alternativa extremamente promissora na construção civil. Contudo, seu emprego, deve ser planejado de maneira a se compreender e respeitar a intrínseca relação existente entre suas etapas construtivas e as soluções técnicas e arquitetônicas, para que se garanta adequado desempenho da edificação em uso. / Cross Laminated Timber (CLT) panels are a relatively new building component to the international construction sector. Their production in Brazil started around six years ago. Since its use is still scarce in the country, academic and technical references are still rare and there are uncertainties about the performance of the panels during the life of the building. In addition, CLT can be considered as an innovation, which is associated to pre-fabrication and digital technologies, being consequently different from usual building techniques. Therefore, the doubts concern not only the panels performance but also the appropriate design of the CLT building. In order to provide recommendations for architectural designs which will use Brazilian CLT panels, this research aims to extend the investigation of CLT in Brazil. The study focuses on structural performance and durability of CLT panels, according to the Brazilian regulation ABNT NBR 15575, and on the construction process of CLT buildings. The performance analysis is based on the following laboratory tests: retention and penetration of the wood preservatives used in the panels manufacture; soft body impact and hard body impact tests and suspended pieces loading tests; water tightness; heat and thermal shock test; delamination tests. Some of the tests results showed nonconformities. This indicates the importance of a quality control process of the wood preservation treatment and bonding of CLT layers, to ensure the proper performance of the building. In conclusion, CLT panels are indeed a promising alternative to the construction sector. However, its use must respect the intrinsic relation between construction steps, as well as technical and architectural solutions, in order to guarantee adequate performance of the CLT building.

The aim of this master thesis is to design a building consisting of joiner workshop and administration part of furniture factory. Building is located in Brno, cadastral area Horní Herpšice. In terms of funcion as well as structure is building devided in two parts, joiner workshop and administration part containing hygienic facilities for workers, canteen for employees and furniture showroom. Joiner workshop is single-deck skelet structure made of glued laminated timber. Administration part has two above-grade floors. Cross laminated timber panels are used for vertical and horizontal bearing structures. Building facade is designed as ventilated, partly made of cement fiber boards, partly of timber boarding along with green panels. The building has one-layer green roof.

A key factor regarding fire safety of timber buildings is the performance of connections between the structural elements, since this determines the load-carrying capacity of the structure. Traditional timber connections do generally perform poorly in a fire compared to surrounding parts since the joints often consist of exposed metal parts and cavities which locally decreases the fire resistance. This weakness does often lead to the appliance of gypsum which removes the aesthetic appearance of timber. Through an innovative timber connection design, the hope is that the failings at elevated temperature are changed from the connection itself to surrounding parts thus increasing the fire resistance to the limits of the connected components. Two types of glue-laminated timber connections have been built and tested at RISE facilities in Borås with the purpose to determine if these could withstand fire exposure for 90 minutes under load. The connections are assembled by expanding hollow steel tubes that clinches the members together and at the same time makes the steel tube yield against the inside of the pre-drilled hole. Pre-stresses are created in the connection during this process that avoids an initial slip if the connection is loaded, which is one of the reasons that this type of connections is suitable in earthquake-prone areas. The joint design results in a significantly increased rotational stiffness, moment capacity and embedded energy of the joint in comparison with conventional timber connections. One of the connections is designed to withstand moment forces. The specimen is built as a beam to beam connection that is subjected to a four-point bending test at both ambient and elevated temperature. The connection withstood 39.5 kNm in ambient temperature and failed after 87 minutes and 6 seconds of fire exposure under load. However, failure in elevated temperature did not occur within the connection, and visual inspection after the test indicated that the steel tubes still were in excellent condition. The connection is therefore expected to have been able to withstand 90 minutes of fire exposure. The other connection is designed to withstand shear-forces and is built as a column to beam connection that is tested at both room temperature and elevated temperature. The connection endured a maximum shear-force of 181.4 kN in ambient temperature, approximately 30 kN higher than previously performed test with identical setup, and failed after 113 minutes of fire exposure under load. The failure in elevated temperature did however not occur inside the connection. The testing is limited to unprotected connections consisting of glue-laminated timber which are tested in accordance with ISO 834. / En nyckelfaktor för brandsäkerheten i träbyggnader är prestandan hos förbanden mellan konstruktionselementen eftersom dessa bestämmer konstruktionens lastbärande kapacitet. Traditionella träförband har i allmänhet dåligt brandmotstånd i förhållande till omgivande delar, detta eftersom förbanden ofta består av exponerade metalldelar och kaviteter som lokalt försvagar brandmotståndet. Dessa svagheter motverkas ofta genom att montera gips vilket negativt påverkar träets estetiska utseende. Genom en innovativ konstruktion av träförband är hoppet att den svaga punkten vid förhöjd temperatur flyttas från själva anslutningen till omgivande delar, vilket ökar konstruktionens brandmotstånd genom att brandmotståndet då begränsas av prestandan hos de anslutna komponenterna. Två typer av limträförband har byggts och testats vid RISE-anläggningen i Borås med syfte att bestämma om dessa under belastning skulle kunna stå emot brandexponering under 90 minuter. Förbanden monteras genom att expandera ihåliga stålrör som klämmer samman elementen och samtidigt deformeras mot insidan av det förborrade hålet. Förspänningar skapas i förbandet under denna process som förhindrar en primär förskjutning om förbandet är lastat, vilket är en av anledningarna till att denna typ av anslutningar är lämpliga i jordbävningsbenägna områden. Denna konstruktion resulterar i en betydligt ökad rotationsstyvhet, momentkapacitet och inbäddad energi i jämförelse med konventionella träförband. En av anslutningarna är konstruerad för att motstå momentkrafter. Provkroppen är byggd som en balk-balkanslutning som utsätts för ett fyrapunkts böjningstest vid både rumstemperatur och förhöjd temperatur. Anslutningen klarade 39.5 kNm vid rumstemperatur och fallerade efter 87 minuter och 6 sekunder av belastning i förhöjda temperaturer. Brottet i förhöjd temperatur inträffade emellertid inte i anslutningen och den visuella inspektionen som utfördes efter testet indikerade att stålrören fortfarande var i utmärkt skick. Anslutningen bedöms därför ha kunnat motstå 90 minuters brandexponering. Det andra förbandet är konstruerat för att motstå tvärkrafter och är byggt som en pelare-balkanslutning som testas vid både rumstemperatur och förhöjd temperatur. Anslutningen klarade en maximal skjuvkraft på 181.4 kN vid rumstemperatur, cirka 30 kN högre än tidigare utfört test med identisk uppställning, och fallerade efter 113 minuters belastning i förhöjd temperatur. Brottet i förhöjd temperatur inträffade emellertid inte i själva anslutningen. Testerna är begränsade till oskyddade förband bestående av limträ som under brandpåverkan testas enligt ISO 834.

Apesar da versatilidade da madeira, seu emprego fica, às vezes, dificultado por não serem totalmente conhecidas as suas propriedades e seu desempenho em diferentes condições de serviço. Neste trabalho, procura-se contribuir para um melhor aproveitamento das espécies tropicais alternativas, em especial no emprego para produção de elementos estruturais de madeira laminada colada, uma vez que o Brasil possui grande potencial dessas espécies, mas ainda sub-utilizadas. Neste contexto, realiza-se a determinação das propriedades físicas, de resistência e de rigidez de algumas espécies e determinam-se também as rigidezes de elementos estruturais obtidos da espécie cujos corpos-de-prova apresentam os melhores resultados. Ensaiam-se vigas montadas com dois tipos de adesivos, duas intensidades de pressão e duas distribuições de lâminas. Adota-se a metodologia experimental recomendada no ANEXO B da NBR 7190:1997 - Projeto de Estruturas de Madeira, da Associação Brasileira de Normas Técnicas (ABNT). Analisam-se os resultados obtidos a partir de conceitos estatísticos. A espécie Cedrinho (Erisma sp) apresentou as melhores respostas, das quais pode-se concluir que os adesivos Cascophen e à base de mamona não influenciaram as propriedades de rigidez das vigas, o mesmo acontecendo para as duas intensidades de pressão, 0,8 MPa e 1,2 MPa. As propriedades de rigidez das vigas de MLC podem ser influenciadas pela distribuição das lâminas ao longo da altura da seção transversal / Despite the wood versatility, its application is, sometimes, difficult because of its properties and performances under differents work conditions are not completely known. The present work seeks to contribute for a better utilization of the alternative tropical wood species, especially in the employment to the production of structural elements of glued laminated timber, once that Brazil has a great potential of these species which are under applicated. In this context, the determination of the physical properties, the strength and the stiffness of some alternative tropical species are realized, and the stiffness of structural elements made of the specie which presented the best results in specimens tests are determinated. Beams are tested with two adhesives classes, two pressure intensities and two ways of lamination. Experimental methods suggested in ANEXO B, NBR 7190:1997 – Timber Structures Design (Brazilian Technical Codes Association) were used. The specie Cedrinho (Erisma sp) presents the best results, and conclusions are made: Cascophen and castor oil adhesives did not influence the beams stiffness properties; the same thing happens for the two pressure intensities, 0,8 MPa and 1,2 MPa. The glulam beams stiffness properties can be influenced by the ways of lamination