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The area of penetration of phenol-formaldehyde resin into aspen (<i>Populus tremuloides</i>) and Douglas-fir (<i>Pseudotsuga menziesii</i>) flakes, and the layer properties of yellow poplar (<i>Liriodendron tulipifera</i>) flakeboard were investigated to determine how they were influenced by various pressing parameters. The evenness of penetration was found to be a function of the natural variability of the wood and was not influenced by the pressing parameters of temperature, moisture content, pressure, or time. These four parameters were found to influence the area of penetration by controlling the viscosity and flow of the resin. The temperature, gas pressure, and platen pressure history at any particular plane through a flakeboard panel thickness were found to be directly and interactively determined by the pressing parameters of platen temperature, initial mat moisture content, and press closing time. The specific gravity profile was observed to be a function of the press closing time while platen temperature and the mat moisture content influenced the amount of springback which the panel exhibited. Layer-shear and the corresponding specific gravity at a particular plane were found to be similarly dependent on environmental history. The layer-shear strength increased consistently toward the surface of the panel and exhibited a lower coefficient of variation nearer the surface. / M.S.

Glued-laminated wood (Glulam) is a versatile material manufactured by gluing two or more layers of wood together with the grain of all laminae running parallel to each other. Glulam beams of many sizes, shapes, and thicknesses can be made. Innovative load-carrying structures such as lattice domes, bridges, and towers can be built using glulam members. But, since wood is a highly variable and anisotropic material it is often difficult to accurately model the response of wood components in large structures to applied loads. Advanced computer techniques such as finite element analysis are being developed to more accurately model structure response. The objective of this study was to evaluate the applicability of the isoparametric beam finite element to model the elastic response of straight and curved glulam beams subjected to three load conditions. Four straight and three curved southern pine glued-laminated beams were subjected to bending about their major axis, bending about their minor axis, and combined bending and compression. Strains were measured at various locations using clip-on electrical transducers; and, deflections were measured at three locations along the length. Transverse isotropy and global modulus of elasticity were assumed ,to determine experimentally beam material properties: longitudinal modulus of elasticity and shear modulus. The analysis was performed by using the finite element program ABAQUS. The experimental and the analytical strain and deflection values of giu1am beams in bending about the major and the minor axes agreed well for most cases. Differences of less than 100/0 between experimental measurements and analytical predictions were found at all locations through the depth of the beams except in the vicinity of the neutral axis. The differences between the measured and the predicted strain and deflections for beams tested in combined bending and axial compression ranged mostly between 0 % and 40 %. / Master of Science

Global climate change is one of the most important tasks that scientists are trying to solve today. With the help of a Lifecycle Analysis (LCA) method, the impact that many materials and services have on the environment and humans, have been determined.  As a task given by Gävleborg County Administrative Board, this work examines which of the material, glulam or steel, is most suitable as load-bearing material for agricultural buildings (barns). The goal of this study is to perform a LCA (Life Cycle Assessment) of the two materials during production, use, transportation and reuse. The steel's advantage is to be reused again without losing its properties and the wood's benefits to be used as an energy source during combustion, is only one of the steps involved in a life cycle analysis.  The information that an LCA study requires can be infinite and complex and therefore needs limitations in resources and time. A system boundary makes a basis on which phases and influences are the vital parts of a study. The system boundary also includes geographical areas. The study examines only local agricultural buildings in Gävleborg, Sweden, with floor areas of approximately 1300 m2 and their global environmental impact.  Environmental impact of a product is usually allocated in several different environmental impact categories, in which the study examines only three of these: global warming, acidification and eutrophication.  The results show a great difference in emissions depending on how the materials are produced and how they are handled after use. It proves that glulam has significant fewer emissions than steel when it used as an energy source instead of being deposited. With help of the weighting method the result show that iron ore produced steel have 1.2 times greater emission then glulam with landfill and 5.2 times greater when it is used in energy recovery. The weight also shows that scrap produced steel have 0.5 less emission than glulam with landfill and 2.4 greater than glulam with energy recovery. / Problematiken kring den globala klimatförändringen är ett av de problem som forskare försöker lösa idag. Med hjälp av metoden livscykelanalys har många material och tjänster utretts gällande dessas påverkan på miljön och människan. På uppdrag från Länsstyrelsen Gävleborg granskas vilket av materialen, trä eller stål, som är lämpligast som stomme i stallbyggnader ur miljösynpunkt. Målet med denna studie är att utföra en LCA (livscykelanalys) av de två materialen vid produktion, användning, transport och återanvändning. Stålets möjligtvis största fördel innebär att det kan återanvändas om och om igen utan att förlora sina egenskaper och trädets möjligheter till återvinning som energi vid förbränning är endast två av de stegen som ingår i en livscykelanalys. Informationen som en LCA studie består av kan vara oändlig och komplex och kräver därför tydliga avgränsningar gällande resurs och tid. En bestämd systemgräns utgör därför ett underlag på vilka faser och påverkningar som är vitala delar för undersökningen. Systemgränsen innefattar också vilka geografiska områden som undersöks. Studien granskar därför lokala lantbruksbyggnader i Gävleborg med golvarea på cirka 1300 m2 och deras globala miljöpåverkan. Olika typer av miljöpåverkan som uppstår från en produkt kategoriseras i miljöeffektkategorier där studien undersöker tre av dessa: den globala uppvärmning, försurning och övergödning. Resultatet visar en stor skillnad i utsläpp beroende på hur materialen producerats och även hur de hanteras efter användning. Det visar sig att limträ har betydligt mindre utsläpp än stål om den kan energiåtervinnas. Med hjälp av viktningsmetoden visar det sig att järnmalm släpper ut 1,2 gånger mer utsläpp från de sammanlagda miljöeffektkategorierna än limträ som deponeras och 5,2 gånger mer om den energiutvinns. Vid viktningen av skrot blir utsläppet 0,5 gånger mindre än limträ med deponi och 2,4 mer än limträ med energiutvinning.

I början av varje nytt projekt stöter man på de olika alternativ av stomme- och bjälklagskonstruktioner som finns att välja mellan, och frågan blir ofta vilken alternativ som är optimal för den aktuella projekteten. Den optimala lösningen för varje projekt existerar inte, på grund av de olika faktorer och förutsättningar som styr projektet, till exempel: ekonomi, typ av byggnad, terrängtyp etc. Frågeställningen i denna rapport är om limträ eller betong är den mest optimala alternativen som stommaterial i det aktuella projektet. Jämförelsearbetet utgående från förutsättningar har gjorts genom att dimensionera delar av ett projekt med både materialen. Fokus har lagts på skillnader i byggnadshöjd, vindstabilitet och grundläggningen. Resultaten tyder på om man ska bygga ett kontorshus eller flervåningshus vore betong mer lämpligare alternativ jämfört med limträ. Skillnaden i byggnadshöjd finns men är förvånansvärt inte så stor mellan de två olika stommaterial. Dock skillnaden varierar avsevärd när det gäller bjälklagshöjd mellan limträ och betong. Detta pga krav på nedböjning och svikt som ställs på limträbjälklag. Båda stommaterial klara vindstabiliteten utan plintar, som är ganska intressant speciellt med tanke på limträets låga vikt. När det gäller grundläggningen, blev skillnaden betydlig större mellan limträ och betong. Dimensionering enligt Eurokoder har gjorts genom egna handberäkningar och även användandet av programvaran Strusoft. / At the beginning of each new project comes across on the different options of frame and floor construction available to choose from, and the question is often which option that is optimal for the current project. The optimal solution for each project does not exist, because of the different factors and conditions that govern the project, such as: economy, building type, terrain type, etc. The issue addressed in this report is on glue-laminated wood or concrete is the most ideal alternative to framing materials in the current project. Comparative work on the basis of preconditions has been made by dimensioning the parts of a project with both materials. The focus was on differences in building height, wind stability and the foundation. The results indicate if you're going to build an office building or apartment building,concrete is more appropriate alternative compared to the glue-laminated wood. The difference in building height is surprisingly not so great between the two different frames. However, the difference varies considerably in terms of floor height between glue-laminated wood and concrete. This is due to requirements for deflection and springines imposed on wood. Both frames can handle wind stability without plinths, which is quite interesting especially in view of the wood's light weight. Regarding the foundation, the difference was significantly greater between glue-laminated wood and concrete. The design according to Eurocodes has been made by hand calculations and also the use of the software Strusofts.

Thesis (M.S.) in Civil Engineering--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 226-228 (v. 1)).

Thesis (M.E.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (p. 124-129). Also available via the World Wide Web.

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 136-140). Also available in electronic format on the Internet.

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