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King, Bryan L. "Wood deck bridges-stress laminated wood panels on steel beams." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1860.
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Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains xi, 157 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 96).
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Weight, Shilo Willis. "A novel wood-strand composite laminate using small-diameter timber." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Spring2007/s_weight_050207.pdf.
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Gereke, Thomas. "Moisture-induced stresses in cross-laminated wood panels /." [S.l.] : [s.n.], 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18427.
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Diss. Nr. 18427 Wiss. ETH Zürich.Vermerk auf Umschlag: IFB, Departement of Civil, Environmental and Geomatic Engineering/ Institute for Building Materials - Wood Physics/ Institut für Baustoffe-Holzphysik. Literaturverz.
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Syron, William Donald. "Strain Rate-Dependent Behavior of Laminated Strand Lumber." Fogler Library, University of Maine, 2010. http://www.library.umaine.edu/theses/pdf/SyronWD2010.pdf.
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Yadama, Vikram. "Experimental investigation of a novel finite element model for Southern pine glulam beams." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-12302008-063816/.
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Torneport, Matilda. "Industrial Requirements for Cross-Laminated Timber Manufacturing." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-104924.
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Wood is a valuable sustainable material that meets the requirements for structural application. Cross-laminated timber (CLT) is a wood-based product that is mainly used in the building industry. Due to the rapid global market increase, a number of new CLT plants are emerging worldwide and thereby a need for standardisation is more than ever. There is no existing harmonised standard for CLT and it means a diversity between manufacturers, CLT products and its layup, which may in turn affects the properties of available CLT in the market. Therefore, this study was performed through literature study and internet-based interviews from five manufacturer in Sweden and Central Europe, to provide more information regarding the industrial requirements for CLT production. Three specific objectives of this study were: (1) wood and adhesive types in CLT production, (2) wood strength classes for CLT production, (3) important requirements for CLT producers and existing standards. Literature review and interviews showed that spruce (Picea abies L. Karst.) in combination with polyurethane (PUR) adhesive is the most commonly used materials in Europe for CLT production, which are approved by EN 16351 (2021). Other wood species, e.g., pine, poplar and birch can be used or are already used in a minor extent. Strength classes for lamellas in CLT are often C24, but timbers with lower strength grades are possible. Some manufacturer use combinations of different strength graded timber and in this small scale study different strength graded timber was in generally the biggest diversity between manufactures. Only a few material properties such as modulus of elasticity, modulus of rupture, compression and shear strength are listed in EN 16351 (2021) and EN 338 (2016), as the factors for quality measurements of the CLT products. This study, however, showed that the critical material properties for the most interviewed CLT producers are merely modulus of elasticity and rarely modulus of rupture.
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Turesson, Jonas. "Diagonal compression of Cross-Laminated Timber." Thesis, Luleå tekniska universitet, Träteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59699.
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Twelve blocks of Cross Laminated Timber (CLT) were built, tested and simulated. Three types of blocks with different laminate directions in the middle/second layers were used: 0/30/0, 0/45/0 and 0/90/0. Simulations with three-dimensional quadratic orthotropic linear elastic finite elements were conducted. The goal was to compare tested in-plane shear stiffnesses for CLT blocks made from Norway Spruce (Picea abies) boards of C24 quality with a finite element (FEM) simulated block stiffness. Three-layer CLT were studied with block dimensions of 600 x 600 x 45 mm. The first and last layer laminate directions were assumed to be 0○. The middle layer laminate directions were 30○, 45○ and 90○. A 1 mm gap was assumed between the side edges. The glued contact surfaces were assumed to be perfectly glued with rigid glue in the simulations. In the practically tested blocks a PVAc D2 classified glue was used. All blocks were simulated and tested in the same loading arrangement as the practical test set-up. The blocks were compressed in the diagonal direction. Blocks of 0/30/0 and 0/45/0 were compressed twice, once over each diagonal. The 0/90/0 blocks were compressed over one diagonal. A total of 19 practical compression tests was performed; in all cases, the displacements were measured in the force- and orthogonal direction. The stiffest loading case, measured in the force direction, was the loading arrangement 0/45/0-A. The weakest loading case, measured in the force direction, was the loading arrangement 0/30/0-B. The same result could be concluded from the FEM simulations. The calculated stiffness in the loading direction was between 1.21 – 1.87 times larger than the measured stiffness. The models pressed in the “weakest” direction gave the largest difference between the simulated and measured stiffness.
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Berglind, Henrik Oförstörande provning. "Nondestructive detection of glue deficiency in laminated wood using thermography /." Luleå, 2003. http://epubl.luth.se/1402-1544/2003/02.
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Jordan, Andrew R. "Wetpreg Reinforcement of Glulam Beams." Fogler Library, University of Maine, 1998. http://www.library.umaine.edu/theses/pdf/JordanA1998.pdf.
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Anshari, Buan. "Structural behaviour of glued laminated timber beams reinforced by compressed wood." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/9115/.
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As an engineered wood product, glued laminated timber (Glulam) is produced to minimise several natural weaknesses such as knots and non-uniform strength in order to enhance its stiffness and load carrying capacity. Many reinforcement methods have been tested, with promising results in increasing the strength and stiffness of beam. Recently, with increasing concern on environmental protection there is a growing trend in construction to use as many natural materials as possible. Therefore, conventional types of reinforcement using metals and/or synthetic materials do not fit well with this trend. A new approach to strengthen Glulam beams using pure natural materials has been established through this research. Glulam beams were strengthened by inserting compressed wood (CW) blocks into the pre-cut rectangular holes on the top of the beams. This practice was to make use of moisture-dependent swelling nature of the compressed wood. As a result, a pre-camber was produced in the mid-span of the beam reinforced. Significant initial tensile and compressive stresses were generated at both the top and the bottom extreme fibres of the beam, respectively. Material tests have been done to investigate material properties of compressed Japanese cedar with different compression ratios. Structural tests were undertaken for short and long Glulam beams strengthened by CW blocks after gained the pre-camber. 3-D finite element models have also been developed by using commercial code ABAQUS to simulate the pre-stressing behaviour of Glulam beams reinforced using compressed wood blocks. The finite element models were used to simulate the structural behaviour of the pre-stressed beams subjected to subsequent destructive bending tests. All computer models developed were validated against corresponding experimental results of the free moisture-dependent swelling, pre-stressing processes and the destructive tests for both the short and long beams. Reasonably good correlation was obtained in terms of the free swelling, the pre-camber, initial stress state of the Glulam beams reinforced and load-deflection relationships. Using validated computer models, parametric studies were further carried out to provide design information for such a reinforcing technique. The results have indicated that the reinforcing techniques using compressed wood blocks are very effective means to enhance the initial stiffness, bending strength and load carrying capacity of Glulam beams. The technology is ready to be applied in practice.
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Reuterswärd, Caspar. "Exploring the repurposing of cross laminated timber spillage." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-161026.
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Forestry is one of Sweden’s largest natural resources and a largeand important foundation for the country’s economic stability.There is a significant opportunity to evaluate material efficiencyand values in the supply chain of industrialised wood-basedproducts. This thesis comprises on handling a spill-product of amodern wood-based building material: cross-laminated timber(CLT). With the aim to increase value of this spill product throughpractical design iteration, material exploration and theoreticalanalysis. The material exploration leads to a collection of furnitureand interior products which are evaluated based on commercialinterest and production feasibility.
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Archila, Santos Hector Fabio. "Thermo-hydro-mechanically modified cross-laminated Guadua-bamboo panels." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675700.
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Guadua angustifolia Kunth (Guadua) is a bamboo species native to South and Central America that has been widely used for structural applications in small and large-scale buildings, bridges and temporary structures. Currently, its structural use is regulated within seismic resistant building codes in countries such as Peru and Colombia. Nevertheless, Guadua remains a material for vernacular construction associated with high levels of manual labour and structural unpredictability. Guadua buildings are limited to two storeys due to the overall flexibility of the slender and hollow culms and its connection systems. Its axial specific stiffness is comparable to that of steel and hardwoods, but unlike wood, Guadua’s hollow structure and lack of ray cells render it prone to buckling along the grain and to transverse crushing. As a result, Guadua’s mainstream use in construction and transformation into standard sizes or engineered Guadua products is scarce. Therefore, this work focussed on the development of standardised flat industrial structural products from Guadua devising replicable manufacturing technologies and engineering methods to measure and predict their mechanical behaviour. Cross-laminated Guadua panels were developed using thermohydro-mechanically modified and laminated flat Guadua strips glued with a high performance resin. Guadua was subjected to thermo-hydro-mechanical (THM) treatments that modified its microstructure and mechanical properties. THM treatment was applied to Guadua with the aim of tackling the difficulties in the fabrication of standardised construction materials and to gain a uniform fibre content profile that facilitated prediction of mechanical properties for structural design. Densified homogenous flat Guadua strips (FGS) were obtained. Elastic properties of FGS were determined in tension, compression and shear using small-clear specimens. These properties were used to predict the structural behaviour of G-XLam panels comprised of three and five layers (G-XLam3 and G-XLam5) by numerical methods. The panels were assumed as multi-layered systems composed of contiguous lamellas with orthotropic axes orientated at 0º and 90º. A finite element (FE) model was developed, and successfully simulated the response of G-XLam3 & 5 panels virtually loaded with the same boundary conditions as the following experimental tests on full-scale panels. G-XLam3 and G-XLam5 were manufactured and their mechanical properties evaluated by testing large specimens in compression, shear and bending. Results from numerical, FE predictions and mechanical testing demonstrated comparable results. Finally, design and manufacturing aspects of the G-XLam panels were discussed and examples of their architectural and structural use in construction applications such as mid-rise buildings, grid shells and vaults are presented. Overall, this research studies THM treatments applied to Guadua in order to produce standardised engineered Guadua products (EGP), and provides guidelines for manufacturing, testing, and for the structural analysis and design with G-XLam panels. These factors are of key importance for the use of Guadua as a mainstream material in construction.
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Xu, Han. "Development of FRP-Glulam Panel for Bridge Deck Replacement." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/XuH2001.pdf.
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Canedy, Nicholas P. "Equestrian Competition Center." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/36241.
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This thesis explores the possibilities of using varied long span glue-laminated
arches to create a dynamic structural enclosure over an expansive open surface.
It investigates using arches that increase and decrease in height and span width,
while varying in their lean. When combined with a fabric enclosure, they create a
roof that constantly changes. The idea is to create a world class equestrian center
that is visually exciting from both the interior and exterior, rather than simply
creating a large scale version of a barn.Master of Architecture
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Koubek, Radek, and Karolina Dedicova. "Friction of wood on steel." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-35094.
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This thesis deals with the experimental description of friction between steel and wood materials, specifically laminated veneer lumber (LVL) and pine wood with two types of annual rings. It studies the influence of a number of different parameters on the coefficient of friction such as contact pressure, moisture content, fiber orientation in relation to the load direction, steel surface roughness, and horizontal load rate. First, the theoretical mechanical and physical properties as well as the coefficient of friction itself are described. This is followed by the description of the test setup including the test method and how the obtained data is exported, handled and processed and how the coefficient of friction is determined. The results study the influence of different parameters and show that the coefficients of friction for the smooth sliding plate tests vary in between 0.1 and 0.3, whereas tests with the rough sliding plate vary around 0.7. Factors influencing the coefficient of friction were found to be the different moisture content under all tested pressures, the different fiber direction under low contact pressure, the contact pressure itself, though under higher pressures the influence was found to be low, and the horizontal load rate under low pressures. The outcomes are further discussed in the discussion chapter.
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Moudgil, Manu. "Feasibility study of using Cross-Laminated Timber core for the UBC Tall Wood Building." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62876.
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Mass-timber has gained popularity in the construction of mid-rise buildings in the last decade. The innovation of constructing tall buildings with mass-timber can be seen in the student residence at Brock Commons built in 2016 at the University of British Columbia. It is the world’s tallest timber hybrid building with 18 stories and 53 meters’ height above the ground level. The building has 17 stories of mass-timber superstructure resting on a concrete podium with two concrete cores that act as a lateral force resisting system for earthquake and wind forces. The mass-timber superstructure of 17 stories took ten weeks whereas the concrete cores were built in fourteen weeks. There could have been a substantial reduction in the project timeline leading to cost savings, if mass-timber was used for the cores. The motivation for concrete cores was driven by the sole purpose of easier approval procedure.
The objective of this thesis was to evaluate the possibility to design the Brock Commons building using mass-timber cores. First, the procedure for the approvals for tall timber buildings by understanding the code compliance for Brock Commons is discussed. Then, the actual building with concrete cores is modeled, with the model being calibrated with the results from the structural engineers of record. These concrete cores are then replaced by the same configuration using Cross Laminated Timber (CLT) cores to investigate the structural feasibility of Brock Commons with a mass-timber core. The results presented herein show that Brock Commons with CLT core having the same dimensions and configuration is unstable under seismic loading for Vancouver, BC, as specified by National Building of Canada 2015. However, when the configuration and thickness of CLT cores are changed, the structure can meet the seismic performance criteria as per the code.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Mansfield-Williams, H. D. "Mode 11 fracture mechanics in solid wood and fracture mechanics in laminated veneer lumber." Thesis, Brunel University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390815.
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Botting, Joshua Keith. "Development of an FRP Reinforced Hardwood Glulam Guardrail." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/BottingJK2003.pdf.
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Richardson, Benjamin Lee. "Examination of the Lateral Resistance of Cross-Laminated Timber in Panel-Panel Connections." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/56969.
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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
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Rara, Angela Dominique Sarmiento. "Rolling Shear Strength and Modulus for Various Southeastern US Wood Species using the Two-Plate Shear Test." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104017.
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Cross-Laminated Timber (CLT) is an engineered wood product made by laminating dimensional or structural composite lumber in alternating orthogonal layers. Compared to Canada and Europe, CLT is a novel product to the US. With the additions included in the 2021 International Building Code (IBC), CLT material properties, especially rolling shear, would need to be explored. The increasing demand for softwood lumber, along with the increase of demand of CLT panel production, could place a burden and surpass the domestic softwood supply. Rolling shear is a phenomenon that occurs when the wood fibers in the cross-layers roll over each other because of the shearing forces acting upon a CLT panel when it is loaded out-of-plane. This study used the two-plate shear test from ASTM D2718 to measure the rolling shear properties of various southeastern US wood species: southern pine, yellow-poplar, and soft maple. A secondary study was conducted, using the same two-plate shear test, to measure the rolling shear properties of re-manufactured southern pine for CLT cross-layer application. The soft maple had the greatest average rolling shear strength at 5.93 N/mm2 and southern pine had the lowest average rolling shear strength at 2.51 N/mm2. Using a single factor analysis of variance (ANOVA), the rolling shear strength values from soft maple were significantly greater than yellow-poplar, which was significantly greater than the southern pine. For the rolling shear modulus, the southern pine and soft maple were of equal statistically significant difference, and both were greater statistically significant different compared to the yellow-poplar. The most common failure found from testing was rolling shear.Master of Science
Cross-Laminated Timber (CLT) is an engineered wood panel product, similar to plywood, constructed with solid-sawn or structural composite lumber in alternating perpendicular layers. The additions included in the incoming 2021 International Building Code (IBC) has placed an importance in expanding the research related to the mechanical and material properties of CLT. Also, with the increasing demand for softwood lumber and CLT panel production, the demand for the domestic softwood lumber could place a burden and surpass the domestic softwood supply. Rolling shear is a failure type that occurs when the wood fibers in the cross-layers roll over each other because of the shearing forces acting upon a CLT panel. This study used the two-plate shear test to measure the rolling shear properties of various southeastern US wood species: southern pine, yellow-poplar, and soft maple. A secondary study was conducted, using the same two-plate shear test, to measure the rolling shear properties of re-manufactured southern pine for CLT cross-layer application. The soft maple had the greatest average rolling shear strength at 5.93 N/mm2 and southern pine had the lowest average rolling shear strength at 2.51 N/mm2. Using a single factor analysis of variance (ANOVA), the rolling shear strength values from soft maple were significantly greater than yellow-poplar, which was significantly greater than the southern pine. For the rolling shear modulus, the southern pine and soft maple were of equal statistically significant difference, and both were greater statistically significant different compared to the yellow-poplar. The most common failure found from testing was rolling shear.
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Poulin, John P. "Bond and Static Bending Strength of FRP-Reinforced Glulam Beams Using Western Wood Species. Vol. 1." Volume 1 Volume 2, 2001. http://www.library.umaine.edu/theses/theses.asp?Cmd=abstract&ID=CIE2001-002.
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Gamache, Christopher P. "Preliminary Investigation on the Durability of FRP Reinforced Glulam Bridge Girders." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/GamacheCP2001.pdf.
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Lindyberg, Robert F. "ReLAM: a nonlinear probabilistic model for the analysis of reinforced glulam beams in bending /." Abstract only, 2000. http://www.library.umaine.edu/theses/theses.asp?Cmd=abstract&ID=CIE2000-001.
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Wilinder, Per. "Fire Resistance in Cross-laminated Timber : Brandmotstånd hos korslaminerat massiv trä." Thesis, Jönköping University, JTH, Civil Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-11653.
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This report deals with the fire resistance of cross-laminated timber (CLT). Themain purpose is to verify a new model on CLT and its ability to sustain itsbearing capacity when exposed to fire. To establish this, a series of bendingtestshas been conducted in combination with fire exposure of the CLT. Twodifferent series, with different dimensions, of beams were tested (series 1 andseries 2). Four basic set-ups: CLT in tension or compression, either equippedwith fire protective covering or not. Results from the tests has been gatheredand evaluated to verify the theoretical model of the fire resistance. Evaluationwas made through analysis of the residual cross-sections of the beamsregarding charring depth and rate and moment of inertia (I).Results of the tests verify to a large extent the Design model. Externalproblems and variations in the beams themselves caused some deviations.Analysis confirmed the CLT as being more similar to other laminated productssuch as Laminated Veneer Lumber (LVL) then homogenous solid beams. BothCLT and LVL experience delamination when exposed to fire resulting in anincreased charring rate. The difference in rate when using Gypsum plaster as aprotective barrier against the fire exposure is also equal to LVL.The results of the report will be used in the new version of the EuropeanStandard, Euro Code 5 and in the third edition of Fire Safe Timber Buildings.Charring rates proved to be less than expected but the CLTs ability to withstandfire while keeping its bearing capacity
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Patel, Monil Chintan. "Investigation of Single and Two Bolt Connections Perpendicular to Grain in Laminated Veneer Lumber." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/44459.
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Bolted connection with perpendicular to grain loading has been considered as a high priority research area by Smith and Foliente (2002), for the advancement of the load resistance factor design (LRFD) of connections. The results obtained from the experimental testing of this research will provide information regarding the behavior of connections at conditions of capacity and yield, and a comparison between single and two bolted connections for laminated veneer lumber (LVL) from different manufacturers. Comparison of the experimental results with the predicted results from three models: Technical Report -12 (AF&PA 1999), Van der Put and Leijten (2000) and Jensen et. al. (2003), for single and two bolt connections loaded perpendicular to grain will help in accurately predicting LVL connection behavior. Success in achieving the goals of this research will provide enhancement of knowledge and information for single and two bolted connections loaded in perpendicular to the grain connections for LVL and thereby help in calibrating LRFD parameters on pure reliability basis in future. The variables considered included LVL from two different manufacturers, single and two bolt connections with different bolt sizes and loaded edge distances. The connections were loaded to capacity for all the tests. Tests for the material property input values required for these models were also performed as a part of this research.
Connection testing showed splitting failures combined with crushing of main member material and formation of a single plastic moment. Connection resistance increased with increased loaded edge distance and number of bolts. The allowable shear design value controlled the National Design Specification Allowable Stress Design (NDS ASD) lateral design value to the connection design except for one connection configuration with 7D loaded edge distance for two bolts of ½ inch, where connection design strength values controlled. The displacement limit decided for the dowel bearing strength test had a direct impact on the predicted TR-12 capacity values. The capacity resistance calculated by both fracture models increased with increase in
loaded edge distances. The Mode-I fracture energy values directly affected the predicted fracture model values. The tension perpendicular to grain strength values directly affected the Jensen model values.
Statistical comparison of 4D and 7D loaded edge distances and LVL-1 and LVL-2 material revealed that Van der Put model had no difference in the calculated to test (C/T) ratios with respect to different loaded edge distances and materials and the Jensen model predicted the C/T ratios at 4D to be significantly greater than at 7D and for LVL-1 to be significantly greater than LVL-2. Van der Put model over predicts at capacity and the C/T values are consistent with change in loaded edge distance. Jensen model C/T ratios over predicted for single bolt connection and predicts accurate for two bolt connection with respect to loaded edge distances. Comparing the two fracture models with a ductile model TR-12 with respect to different loaded edge distances, material, number and size of bolts, Jensen model best predicted the C/T ratios. The Van der Put model tended to over predict values, while the TR-12 model had no consistent trend in C/T ratios, but seemed to be affected inversely by changes in loaded edge distance.Master of Science
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Buck, Dietrich. "Mechanics of Cross-Laminated Timber." Licentiate thesis, Luleå tekniska universitet, Träteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-68729.
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Increasing awareness of sustainable building materials has led to interest in enhancing the structural performance of engineered wood products. Wood is a sustainable, renewable material, and the increasing use of wood in construction contributes to its sustainability. Multi-layer wooden panels are one type of engineered wood product used in construction. There are various techniques to assemble multi-layer wooden panels into prefabricated, load-bearing construction elements. Assembly techniques considered in the earliest stages of this research work were laminating, nailing, stapling, screwing, stress laminating, doweling, dovetailing, and wood welding. Cross-laminated timber (CLT) was found to offer some advantages over these other techniques. It is cost-effective, not patented, offers freedom of choice regarding the visibility of surfaces, provides the possibility of using different timber quality in the same panel at different points of its thickness, and is the most well-established assembly technique currently used in the industrial market. Building upon that foundational work, the operational capabilities of CLT were further evaluated by creating panels with different layer orientations. The mechanical properties of CLT panels constructed with layers angled in an alternative configuration produced on a modified industrial CLT production line were evaluated. Timber lamellae were adhesively bonded in a single-step press procedure to form CLT panels. Transverse layers were laid at a 45° angle instead of the conventional 90° angle with respect to the longitudinal layers’ 0° angle. Tests were carried out on 40 five-layered CLT panels, each with either a ±45° or a 90° configuration. Half of these panels were evaluated under bending: out-of-plane loading was applied in the principal orientation of the panels via four-point bending. The other twenty were evaluated under compression: an in-plane uniaxial compressive loading was applied in the principal orientation of the panels. Quasi-static loading conditions were used for both in- and out-of-plane testing to determine the extent to which the load-bearing capacity of such panels could be enhanced under the current load case. Modified CLT showed higher stiffness, strength, and fifth-percentile characteristics, values that indicate the load-bearing capacity of these panels as a construction material. Failure modes under in- and out-of-plane loading for each panel type were also assessed. Data from out-of-plane loading were further analysed. A non-contact full-field measurement and analysis technique based on digital image correlation (DIC) was utilised for analysis at global and local scales. DIC evaluation of 100 CLT layers showed that a considerable part of the stiffness of conventional CLT is reduced by the shear resistance of its transverse layers. The presence of heterogeneous features, such as knots, has the desirable effect of reducing the propagation of shear fraction along the layers. These results call into question the current grading criteria in the CLT standard. It is suggested that the lower timber grading limit be adjusted for increased value-yield. The overall experimental results suggest the use of CLT panels with a ±45°-layered configuration for construction. They also motivate the use of alternatively angled layered panels for more construction design freedom, especially in areas that demand shear resistance. In addition, the design possibility that such 45°-configured CLT can carry a given load while using less material than conventional CLT suggests the potential to use such panels in a wider range of structural applications. The results of test production revealed that 45°-configured CLT can be industrially produced without using more material than is required for construction of conventional 90°-configured panels. Based on these results, CLT should be further explored as a suitable product for use in more wooden-panel construction.External cooperation: Martinson Group AB and Research Institutes of Sweden (RISE)
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Richie, Matthew. "Fatigue Behavior of FRP-Reinforced Douglas-Fir Glued Laminated Bridge Girders." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/RichieMC2003.pdf.
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Baskota, Karki Subheksha, and Hans Freij. "New fast connection for a building system based on green-glued boards." Thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-5472.
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Växjö university has together with Södra developed a new green-glued laminated beam, which to be used in a building system. To make a product of the beam it is desired to also develop a building system based on the beam. An important part of such a building system is the connections. The main aim of the thesis was to design a new beam-to-beam connection in for the new green-glued laminated boards. This thesis is about to develop and test a new connection for a beam-to-beam connection in the building system. The requirements set on the connection was that it should be used in an office building with a beam length of 6 m, the connection should be fast to assemble and invisible. The report thoroughly describes the conceptual design, the development and test of the connection. Five different types of connections were designed in the conceptual design phase. One of these connections fulfilled the requirements and was taken to the development and testing phase. Three versions of the connection were tested. The report describes how the green-glued laminated beams with the connections were tested in a testing machine until the failure occurs. The developed connection could fulfil the requirements set on the connection. One version of the connection was even stronger than the green-glued laminated beams.
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SCALBI, AGNESE. "Nonlinear numerical approach to the analysis of Cross-Laminated Timber." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/245475.
Full textAbstract:
This research project investigates the shear behaviour of Cross-Laminated Timber (CLT) panels through in-plane shear tests. More precisely, it aims to study the post-elastic behaviour and the damage evolution. Load-displacement curves were experimentally determined, and the Cohesive Zone Model (CZM) is then used to reproduce the experimental results and to identify cohesive crack properties of CLT. A finite element model is used for the identification; it is based on the modulus of elasticity and fibres orientation of Spruce timber. The CZM can capture the nonlinear behaviours and the damage evolution under increasing load, which often occurs in the fracture process zone ahead of the crack tip.
In the model, the timber is idealised as an orthotropic elastic quasi-brittle material. These parts are joined by interfaces, simulating the adhesive layers, that have a traction-separation law with a CZM behaviour. The nonlinearity and the fracture behaviour (and the discontinuity, indeed) develop along these interfaces. Before cracking, the “composite” material obeys the rules of orthotropic elasticity.
By the comparison of the numerical and experimental stress-strain curves, the main parameters of the CZM are identified. The model shows great potential to predicting the load-carrying capacity of the CLT panels; cohesive elements can be effectively used to investigate the interaction with timber layers where crack propagation can govern the failure of the panel.
The results of this work permit to have an accurate model to predict, even in different situations, the nonlinear behaviour of CLT panels, including their fracture behaviour, which could be very important in view of seismic applications in new and existing buildings.
Further analysis would help build a complete understanding of the limits and nonlinear properties of this construction material. In first should be enhanced the approach about the initial stiffness of the wooden element due to the possible effects of the adhesive absorption. Additionally, different 3D models should be used for the modelling of the CLT failure with the aim to assess the possibility to obtain a better fitting of the experimental data.
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Rahayu-Sekartiing, Istie. "Characteristics of lathe check and surface roughness of fast growing wood veneers and their performance on laminated veneer lumber." Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0034/document.
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Pour répondre à la demande croissante de bois et pour préserver les forêts primaires, les méthodes de sylviculture les plus dynamiques ont été privilégiées de manière générale sur la planète.. Les objectifs de la recherche étaient 1) déterminer le point de démarcation/ âge de transition entre le bois juvénile et le bois mature sur sengon (Falcataria moluccana), jabon(Anthocephalus cadamba Miq.), peuplier (Populus sp) et douglas (Psedotsuga menziesii); 2) analyser l'effet de la juvénilité sur un fissuration cyclique, la rugosité et de mouillage; 3) analyser l'effet de la fissuration cyclique et juvénilité sur la résistance à l'adhérence de la colle et les propriétés mécaniques du LVL en flexion; et 4) appliquer un nouveau modèle analytique pour estimer la variation du module d'élasticité du lamibois (sengon et jabon) depuis la moelle vers l'écorce. A partir de la longueur des fibres, le point de démarcation entre le bois juvénile et le bois mature ont été estimés. Pour les essences sengon and jabon, les placages obtenus à partir du cœur des arbres, réputés juvéniles, sont plus fissurés plus rugueux et avec une haute mouillabilité comparativement à ceux obtenus à partir du bois près de l’écorce (plus mature). Une phase d’étuvage préliminaire des bois dans un bain d’eau chaude à 75°C pendant 4 heures a permis d’améliorer sensiblement la qualité des placages en diminuant la fissuration, la rugosité et s’accompagne d’une augmentation de la mouillabilité. La résistance à l'adhérence de la colle, et les modules élastiques et de rupture spécifiques (SMOE et SMOR) du LVL (jabon et sengon) diminuent à mesure que la fréquence de fissure augmente ou en partant de l'écorce vers la moelle. L'avantage de l'utilisation de placages en peuplier de bois mature a été prouvé avec une amélioration de 15 à 20% en moyenne pour les propriétés mécaniques, pour un poids de panneau comparable. Pour le douglas, l'utilisation de placages de bois mature dans la constitution des panneaux de LVL permet également d’améliorer les performances en flexion (de 7 à 22 % sur el MOR). Le modèle analytique a été utilisé afin de prédire les variations du module élastique allant de la moelle à l’écorce. Il permet à partir d’un grand nombre de combinaisons d’estimer le potentiel issu d’une ressource donnée. Pour le contexte de l’étude qui représente bien le potentiel sylvicole de l’Indonésie, la proportion de bois juvénile étant quasi-totale (100%), l’action de trier les placages n’est pas apparue comme pertinenteThe development of plantation and community forest to meet wood demand in society has produced fast growing wood species. The research objectives were 1) to determine demarcation point/transition age between juvenile and mature wood on sengon (Falcataria moluccana), jabon (Anthocephalus cadamba Miq.), poplar (Populus sp) and douglas fir (Psedotsuga menzii); 2) to analyze the effect of juvenility on lathe check, surface roughness and wettability; 3) to analyze the effect of lathe check and juvenility on glue bond strength and laminated veneer lumber (LVL) bending properties; and 4) to apply a new analytical model to determine the variation of specific MOE LVL values of sengon and jabon from pith to bark. Based on fiber length trait, the demarcation point between juvenile and mature wood were approximately at segmented rings 17th (sengon) and at segmented ring 24th (jabon). While, transition age of poplar cultivars and douglas-fir, transition age happened approximately at 12 years old and 18 years old, respectively. The results showed that wood near pith on sengon and jabon resulted veneers with higher lathe check, rougher surface and high wettability, while wood near bark resulted veneers with lower lathe check, smoother surface and low wettability. Glue bond strength, Specific MOE (SMOE) and Specific MOR (Modulus of Rupture) of sengon and jabon LVL were decreased as the frequency of lathe check increased or those strength values increased from pith to bark. The advantage of using poplar veneers from mature wood was proved with an improvement of 15 to 20% on average for mechanical properties, while for douglas-fir, was 7 to 22%. An analytical model was used to predict the variation of the LVL mechanical characteristics using different scenarios. According to the context of this study assumed to be close to the Indonesian resource there is no need to sort veneers since most of the tree is juvenile wood for logs no older than 7
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Finkenbinder, David Edward. "An Experimental Investigation of Structural Composite Lumber Loaded by a Dowel in Perpendicular to Grain Orientation at Yield and Capacity." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35055.
Full textAbstract:
The research summarized by this thesis was comprised of an experimental analysis of beams loaded perpendicular to grain at midspan by a bolted double-shear laterally-loaded connection. Connection specimens were loaded monotonically until capacity was reached. Variables of consideration included the loaded edge distance of the connection main member, the span:depth ratio of the main member, and the main member material. Southern pine machine-stress-rated (MSR) lumber, laminated veneer lumber (LVL), and parallel strand lumber (PSL) were the three material types included in the program.
Experimental results were compared with theoretical predictions from three models: the yield theory-based general dowel equations, which are currently the standard for laterally-loaded connection design in the U.S., and two models based upon fracture mechanics. All material property inputs required by the three models, were measured in the experimental program of this research and used to produce theoretical predictions. Comparisons were also made with respect to design values in the form of calculated factors of safety, over-strengths, and design factors of safety.
Test results and observed trends are provided for all connection and material property tests. Notable trends included failure by splitting for all connections at low loaded edge distances, and variable span:depth ratios generally having a negligible effect on both connection and model performance. In most cases, the general dowel equations were more accurate than the two fracture models, however it should be noted that all three models over-predicted connection capacity at low loaded edge distances.Master of Science
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Brady, Derwood E. "The effect of hot-pressing parameters on resin penetration and flakeboard layer properties." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/101166.
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The area of penetration of phenol-formaldehyde resin into aspen (Populus tremuloides) and Douglas-fir (Pseudotsuga menziesii) flakes, and the layer properties of yellow poplar (Liriodendron tulipifera) 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.
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Šmíra, David. "Využití zrychlených testů trvanlivosti lepených spojů dřeva pro predikci životnosti spoje." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226806.
Full textAbstract:
The aim of my diploma thesis are methods which are able to describe durability aspects of glued wooden joints. The main objective are methods which primarily includes hygrothermal stress acting in the glued joint of wooden adherend and determine the service life of the specific glued joint by modelling based on Arrhenius relation and the other methods. Other part of this work is aimed to shear tests of the samples exposed to different thermal and humidity conditions and for individual sets of exposures determining the glue penetration depth into the wooden adherend by EPI fluorescent analysis. These analytic methods are used for quality check of the glued joints, which are mostly based on strength, chemical or structural parameters of the tested sample.
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POZZA, LUCA. "Ductility and behaviour factor of wood structural systems - Theoretical and experimental development of a high ductility wood-concrete shearwall system." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3422988.
Full textAbstract:
This dissertation focuses on the seismic behavior, ductility and dissipative capacity of modern timber buildings. A number of innovations in the field of timber structures are reported with special regard to the modeling techniques suitable for timber joints and to the characterization of the seismic behavior of modern timber systems.
A preliminary overview on the seismic-resistant timber building technology and on their evolution from the past to nowadays is reported in the introduction of this thesis work. A review of the state of art about the available seismic codes is also reported and the main lack and incongruence with the current constructive practice are pointed out.
The basic terms and concepts used in structural modeling and nonlinear analysis of timber structure are provided in the first part of this dissertation. The specific behavior of wood joints under cyclic actions and therefore under earthquakes is described with emphasis to the pinching effect and strength and stiffness degrading. A literature review on the main numerical models proposed to reproduce the hysteretic load-slip curve of single fasteners, joints and whole wooden elements is presented and discussed. A proposal for a new wood joint numerical model that can be easily implemented into a standard commercial Finite Element code is reported. The reliability of such new developed model to reproduce the fasteners hysteresis behavior is presented and critically discussed in comparison with experimental results.
The second part of this thesis work is based on the evidence that the growing spread of the use of timber structures has led to the development of numerous innovative construction systems but at the same time a lack of code provisions for seismic timber structure still remains, in particular concerning the ductility (or behavior) factor q to be used for the design of different timber systems. This part of dissertation analyzes the definitions of the q-factor given in the scientific literature and its relevance in the design of seismic resistant structures. The traditional methods for estimating the q-factor are investigated and an innovative procedure for expeditious q-factor estimation is presented. The theoretical aspects of this new analytical-experimental procedure are reported and the main advantages and limitations are critically discussed.
The seismic behavior of the Cross Laminated Timber structure is in deep studied in the third part of this dissertation. Such building system is largely spreading in the constructive practice but no design guidelines are provided in the seismic codes yet, especially for what concerning the definition of their sound behavior factor. Aim of this part of dissertation is to define the influence of some significant building characteristics, such as building technology, storeys number, slenderness, design criteria etc.., on the q-factor value. Such influences were studied referring to a numbers of building configuration and by means of nonlinear analyses carried out using specific hysteretic spring lamp-mass models. Based on such numerical assessment a proposal for an analytical formulation suitable to calculate the q-factor of CrossLam buildings has been developed and is presented. The validation and the applicability limits of the proposed formulation are presented and critically discussed.
The final part of the dissertation investigates from the structural efficacy of newly developed construction technology which uses an external concrete shelter made of precast R.C. slabs to improve the performance of standard platform-frame shear walls. The idea consists of external plating made of thin reinforced concrete slabs screwed to the wooden frame of the walls. The concrete slab acts as a diaphragm against the horizontal forces. The structural response of this shearwalls under monotonic and cyclic loading conditions has been assessed by means of experimental tests. The tests outcomes are presented and compared with those from code provisions. Fulfillment of the requirements given by current codes as regards the attribution to the Higher Ductility Class is also verified. The influence of concrete skin on the seismic response of the shearwalls is also evaluated by means of numerical analysis and the assured “q” ductility factor is estimated.In questo lavoro di tesi si analizzano il comportamento sismico, la duttilità e la capacità dissipativa dei moderni edifici con struttura di legno. Le principali innovazioni sviluppate in questa tesi di dottorato riguardano le tecniche di modellazione dei sistemi di connessione usati nelle strutture lignee e la caratterizzazione sismica dei moderni edifici in legno. L’introduzione della tesi evidenzia le caratteristiche che rendono le strutture in legno idonee per l’impiego in zona sismica e riporta una analisi storica delle principali tipologie di edifici sismo-resistenti a struttura in legno e la loro evoluzione dal passato ai giorni nostri. L’introduzione riporta inoltre un’analisi critica dello stato normativo Europeo ed Extraeuropeo sulle progettazione sismica degli edifici a struttura in legno evidenziando le principali lacune e incongruenze con la pratica costruttiva corrente. Il lavoro di tesi sviluppato affronta sostanzialmente quattro argomenti dettagliati in parti indipendenti. Le prime due sono di carattere generale e riguardano tutte le strutture in legno mentre le rimanenti sono specifiche di sistemi costruttivi innovativi e non ancora completamente caratterizzati sismicamente. La prima parte della tesi è dedicata alla descrizione del comportamento isteretico che caratterizza le connessioni utilizzate nelle strutture in legno e dei modelli numerici disponibili in letteratura per una riproduzione fedele di tale comportamento evidenziandone le potenzialità, i limiti di applicazione e l’efficienza numerica. Viene inoltre proposto un modello isteretico innovativo per riprodurre il comportamento delle connessioni tipicamente utilizzate nelle strutture in legno riproducibile anche mediante codici agli elementi finiti di tipo commerciale e non specificatamente orientati alla ricerca. Questa prima parte della tesi si conclude con la validazione e la descrizione dei principali vantaggi e limiti di applicazione della modello numerico proposto. La seconda parte della tesi riguarda la definizione del fattore di struttura q dei sistemi costruttivi in legno innovati e di recente diffusione che non sono annoverati nelle normative sismiche. In questa parte della tesi vengono descritti i metodi tradizionali utilizzati per la stima del fattore di struttura evidenziandone i vantaggi e i principali limiti. Viene proposta una procedura innovativa di tipo misto analitico-sperimentale che consente una valutazione speditiva del valore del fattore di comportamento q.. Questa parte del lavoro di tesi si conclude riportando la validazione della procedura proposta nonché gli aspetti teorici i limiti di applicabilità. La terza parte della tesi approfondisse lo studio sul sistema costruttivo a parete massiccia del tipo CrossLam. Preliminarmente viene riportatolo lo stato dell’arte sull’attività di ricerca sinora svolta su tale sistema costruttivo. L’obiettivo di questa parte del lavoro di tesi consiste nella definizione dell’effetto di determinate caratteristiche dell’edificio come il numero di piani, la snellezza, la composizione delle pareti, i criteri di progetto ecc. sul valore del fattore di struttura da utilizzare nella progettazione sismica dell’edificio stesso. Tale correlazione viene studiata mediante una serie di simulazioni numeriche su diverse configurazioni di edifici. I risultati ottenuti sono stati sintetizzati in una nuova formulazione analitica per la definizione del fattore di struttura q a partire dalle specifiche caratteristiche dell’edificio. Infine si riporta la validazione di tale formulazione analitica e si descrivono i principali vantaggi e limitazioni. L’ultima parte di questo lavoro di tesi consiste nello sviluppo teorico e sperimentale di un nuovo sistema costruttivo misto legno-calcestruzzo ad alta duttilità e performance anti-sismiche. Il sistema sviluppato consiste nell’applicazione di un rivestimento esterno in lastre di calcestruzzo alle tradizionali pareti di taglio a telaio. La riposta strutturale, la duttilità e il comportamento isteretico è stato verificato mediante dei test sperimentali condotti su differenti configurazioni di pareti. Infine sono state condotte delle simulazioni numeriche, con modelli numerici appositamente sviluppati e tarati sulla base dei test sperimentali, mediane le quali è stato possibile stimare il valore del fattore di struttura q da utilizzare per il progetto sismico di questo nuovo sistema costruttivo.
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Aljija, Elnes. "Jämförelse Mellan Lätt och Tung Stomme på ett Kontorshus." Thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-19176.
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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.
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Eliassi, Kamal. "Hur påverkas miljön av limträ- eller stålstomme för en lantbruksbyggnad?" Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-22818.
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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.
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Zangiácomo, André Luiz. "Emprego de espécies tropicais alternativas na produção de elementos estruturais de madeira laminada colada." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-26052006-150001/.
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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 transversalDespite 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
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Marinho, Nelson Potenciano. "Características das fibras do bambu (Dendrocalamus giganteus) e potencial de aplicação em painéis de fibra de média densidade (MDF)." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/369.
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O aumento da demanda por madeira e a redução da sua disponibilidade tem direcionado investigações para o aproveitamento de materiais alternativos, naturais e renováveis. Constituído por fibras de elevada resistência mecânica e uma das maiores taxas de crescimento, o bambu surge como uma alternativa promissora para o uso industrial. Os painéis de fibra de média densidade (MDF - Medium Density Fiberboard) são tecnologias recentes que procuram maximizar o aproveitamento e valorização das madeiras. Neste contexto, a presente pesquisa teve como objetivo investigar as características anatômicas e químicas das fibras do bambu da espécie Dendrocalamus giganteus e, na forma de painéis de MDF, avaliar as suas propriedades físico-mecânicas como: densidade, teor de umidade, inchamento em espessura, absorção de água, flexão estática e a tração perpendicular à superfície, segundo as normas ABNT e EN. A composição química foi obtida por meio de análises em EDS (Energy Dispersive X-Ray Spectroscopy) e visualizada suas concentrações por meio de imagens do Microscópio Eletrônico de Varredura (MEV) sendo o principal elemento o silício. Para a produção das fibras foi empregado o método quimotermomecânico com 4 diferentes tipos de tratamentos, a fim de compará-los entre si. Na composição dos painéis foi utilizada a resina Uréia Formaldeído (UF) em percentuais de 10%, com 2,5% de catalisador e 2% de parafina. O maior rendimento bruto de polpação e o número Kappa mais alto foram encontrados no painel T-1 com 79.3% e 177.5, respectivamente. Nas avaliações das propriedades físico-mecânicas os resultados das análises estatísticas indicaram as melhores relações de desempenho com o painel T-3. Para a melhor compreensão do comportamento mecânico foram realizadas análises micrográficas em MEV e Microtomografia nas regiões de fraturas. As análises térmicas (TG) apresentaram fibras resistentes com estabilidade térmica em faixa de temperatura de até 350ºC. Os resultados desta pesquisa apontam para um potencial tecnológico de painéis de MDF produzidos a partir das fibras do bambu, desde que tenham os processos apropriados.The increased demand for wood and the reduce on its availability is directing the investigations for alternative, natural and renewable materials use. Formed by fibers with high mechanical resistance and with the highest grow rate, bamboo emerges as a promising alternative for industrial purpose. The panels of medium density fiberboard (MDF) are technologies that aim to maximize use and appreciation of wood. In this context this study had the objective of investigate anatomical and chemical characteristics of bamboo fiber from Dendrocalamus giganteus, and in form of MDF panel, evaluate its physical-mechanical properties, such density, moisture content, thickness swelling, water absorption static bending and tension perpendicular to surface, according with ABTN and EN rules. The chemical composition was evaluated by Energy Dispersive X-Ray Spectroscopy (EDS) and illustrated by Scanning Electron Microscope (SEM) being the silicon the main component. For fiber production was applied chemical-termomechanical process with four different treatments with the objective of compare it. In panel composition was used Urea Formaldehyde resin (UF) in 10% of resin, 2.5% of catalyst and 2% of paraffin. The highest yield of pulp and highest Kappa number were obtained on panel T-1 with 79.3% and 177.5, respectively. On physical and mechanical properties evaluation, the results of statistical analysis indicate the best performance in T-3 panel. For better comprehension of mechanical behavior, scanning electron microphotography and microtomography in fracture regions were obtained. Thermal analyses (TG) showed resistant fibers with thermal stability in temperature range up 350ºC. The results of this research showed the technological potential of MDF panels produced with bamboo fibers.
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Müller, Marcos Theodoro. "INFLUÊNCIA DE DIFERENTES COMBINAÇÕES DE LÂMINAS DE Eucalyptus saligna E Pinus taeda EM PAINÉIS ESTRUTURAIS LVL." Universidade Federal de Santa Maria, 2009. http://repositorio.ufsm.br/handle/1/8653.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis research aimed at investigating the influence of the positioning of Eucalyptus saligna and Pinus taeda wood veneers on the layers composing the Laminated Veneer Lumber (LVL) structural panels. The panels were manufactured in six different combinations of five veneers of 3,2 mm, glued with phenol-formaldehyde, resulting in treatments constituted of wood of the same species or with a composition of the two wood types. The evaluation of the proposed combinations was performed under the characterization of physical properties (moisture content, density, water absortion, thickness swelling and volumetric expansion) and mechanical properties verified in flatwise and edgewise static bending (modulus of elasticity, stress at the proportional limit and modulus of rupture). The quality of the adhesive wood bonding was evaluated through the glue line shear strength by compression loading and the percentage of wood failure. Wood bonding tests were done with wood of the same species and wood of two studied types. The results obtained indicated that, in most situations, the different positionings of the veneers with larger density (in the outer, intermediate and inner layers) influenced the mechanical properties of the panels. The influence detected was varied, especially for MOE and MOR when comparing the flatwise and edgewise experimented positions. In certain positions, in the layers of the LVL compositions, the presence of eucalypt veneers resulted in stiffness and strength increases. In dry shear the resistances of the joints were shown to be equivalent; after boiling, the joints in eucalypt veneers presented larger strength. The percentage of wood failure was above 80% (in eucalypt veneers) and above 90% (in pine and mixed veneers) and maintained stable after boiling, indicating good gluing quality for all the tested wood bondings. However, it was verified that the adhesive wood bonding of eucalypt and pine was shown more reliable than the bonding between eucalypt veneers. Therefore, the treatments formed by interposed veneers of eucalypt and pine presented a better combination of performance and reliability for the properties of stiffness, strength and adherence.
Investigou-se a influência do posicionamento de lâminas de madeira de Eucalyptus saligna e Pinus taeda nas camadas componentes de painéis estruturais Laminated Veneer Lumber (LVL). Os painéis foram manufaturados em seis diferentes combinações de cinco lâminas de 3,2 mm de espessura, coladas com adesivo fenolformaldeído, resultando em tratamentos constituídos de madeira de uma mesma espécie e outros com mistura de madeira das duas espécies. A avaliação das combinações propostas foi realizada mediante a caracterização de propriedades físicas (teor de umidade, massa específica, absorção de água, inchamento em espessura e expansão volumétrica) e propriedades mecânicas, verificadas em ensaios de flexão estática flatwise e edgewise (módulo de elasticidade, tensão no limite proporcional e módulo de ruptura). A qualidade da colagem foi avaliada por meio da resistência ao cisalhamento na linha de cola por ensaio de compressão e do percentual de falha na madeira. Foram testadas colagens de madeira de mesma espécie e entre madeiras das duas espécies estudadas. Os resultados obtidos indicaram que, na maior parte das vezes, os diferentes posicionamentos das lâminas de maior massa específica (nas camadas externas, intermediárias e de miolo) influíram nas propriedades mecânicas dos painéis. A influência constatada mostrouse variada, em especial para MOE e MOR, quando comparados os valores para as posições de ensaio flatwise e edgewise. Em determinadas posições, nas camadas das composições LVL, a presença de lâminas de eucalipto resultou em aumentos de rigidez e resistência. Em cisalhamento a seco, as resistências das juntas se mostraram equivalentes; entretanto, após fervura, as juntas entre lâminas de eucalipto apresentaram maior resistência. Os percentuais de falha na madeira foram superiores a 80% (entre lâminas de eucalipto) e a 90% (entre lâminas de pinus e em juntas mistas) e se mantiveram estáveis após a fervura, indicando boa qualidade de adesão para todas as colagens testadas. Entretanto, a colagem entre eucalipto e pinus mostrou-se mais confiável que a colagem entre lâminas de eucalipto. Contudo, os tratamentos formados por lâminas intercaladas de eucalipto e pinus apresentaram uma melhor combinação de performance e confiabilidade para as propriedades de rigidez, resistência e aderência.
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Decker, Brandon T. "In-Plane Lateral Load Capacities of Vertically Oriented Interlocking Timber Panels." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5304.
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The Vertically Oriented Interlocking Timber (VOIT) panel is a new solid wood panel similar to Interlocking Cross Laminated Timber (ICLT) and the more commonly known Cross Laminated Timber (CLT). Like ICLT, VOIT panels use timber connections instead of the adhesives or metal fasteners common to CLT. The difference of VOIT is the orientation of the layers. Where CLT and ICLT panels alternate the orientation of each layer, VOIT panels orient all the layers in the same direction. The vertically oriented layers are then attached to one another by smaller horizontal dovetail members.Two types of VOIT panels were provided to be tested for in-plane lateral loading. Type I had three rows of horizontal dovetail members connecting the layers and Type II had four rows of dovetail members as well as two diagonal members to provide stiffness. Two panels of each type were provided, measuring 8 ft. wide, 8 ft. tall, and 13.75 in. thick. Each panel was disassembled after monotonic lateral in-plane loading to determine possible failure modes. Testing results suggest the VOIT panels to be comparable in shear strength to other wood shear walls, including light frame, CLT, and ICLT walls. A two-part analytical model was created to determine the deflection of the wall when loaded as well as the shear strength of the wall. The model predicted deflection and wall strength reasonably well. Due to the small sample size, additional testing is necessary to confirm the results of the Type I and Type II VOIT panels. Additional testing with more variations of the panel and member geometries is also needed to validate the scope of the model.
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Sundberg, Martin, and David Åsberg. "Husväggar av massivträ: En kostnadsjämförelse." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Byggnadsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-18579.
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Trä är och har sedan länge varit en av Sveriges mest exporterade råvaror. Branschen sysselsätter idag omkring 100 000 människor i landet. I samband med de senaste årens miljödiskussioner bör husens uppbyggnad diskuteras. Syftet med detta examensarbete är att främja husbyggnation i massivträ som de senaste åren fått mer publicitet inte bara på den svenska marknaden men också i centraleuropeiska länder. Frågorna i detta arbete handlar om att identifiera de vanligast förekommande ytterväggskonstruktionerna och jämföra deras materialkostnader samt kostnader för arbete vid montering. För att ha kunnat göra en rättvis jämförelse har BBR’s energikrav varit den gemensamma nämnaren för ytterväggskonstruktionerna. Frågorna har besvarats genom intervjuer med tillverkare av prefabricerade massivträväggar, träregelväggar och betongväggar varpå energiberäkningar utförts i samband med framtagning av olika väggkonstruktioner för att få fram tre lika energieffektiva väggar. Dessa väggar har sedan kostnadsjämförts. Resultatet visar att den vanligast förekommande massivträväggen består av tre till fem lager korslimmade bräder som tillsammans bildar en KL-skiva. På dessa kan isolering och fasad appliceras och på så sätt få en vägg jämförbar med en träregelvägg eller betongvägg. Det visade sig efter gjorda undersökningar att massivträväggen är marginellt dyrare än träregelväggen men väsentligt mycket billigare än betongväggen.Wood is and has long been one of Sweden’s most exported commodities. The industry currently employs about 100 000 people in the country. In conjunction with the recent environment discussions the construction of houses should also be discussed. The purpose of this study is to promote housing construction in solid wood, which in recent years has received more publicity not only in the Swedish market but also in central European countries. The questions in this project is about identifying the most common exterior wall constructions and compare their costs for materials and labor costs during assembly. To have a fair comparison, the BBR's energy requirements have been the common denominator of the exterior wall constructions. The questions have been answered through interviews with manufacturers of prefabricated solid wooden walls, wooden stud walls and concrete walls after which energy calculations conducted in connection with the development of various wall constructions to produce three equal energy-efficient walls. These walls have then been compared by their costs. The results show that the most common wall of solid wood consists of three to five layers of cross-laminated planks that make up a CLT-board. On these insulation and façade are applied and thus obtain a wall which is similar to the wooden stud wall or concrete wall. It was found after the investigations were made that the wall of solid wood is marginally more expensive than the wooden stud wall but significantly cheaper than the concrete wall.
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Lopez-Molina, America Maria. "The Effect of Steel Strapping Tensioning Technique and Fibre-Reinforced Polymer on the Performance of Cross-Laminated Timber Slabs Subjected to Blast Loads." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38247.
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Engineered wood products (EWP) are becoming extremely popular and a viable material option for the construction of residential, commercial, and hybrid buildings. Cross-laminated timber (CLT) is among one of the many EWP available in North America, which can be utilized for many different applications such as: walls, floors, and roofs. Despite the available requirements in the Canadian blast design standard (CSA, 2012) with regard to the design of wood structures, there are currently no provisions on how to retrofit timber structures to improve their performance when subjected to blast loads. The current study is aimed at investigating the effect of different retrofitting alternatives in order to improve the overall behaviour of CLT when exposed to out-of-plane bending.
The experimental program examined the behaviour of seventeen reinforced CLT slabs. Testing was conducted at the University of Ottawa by means of a shock tube capable of simulating high strain rates similar to those experienced during a blast event. The current study was divided into two phases. The first consisted of CLT slabs retrofitted with steel straps where strap spacing, location, and order of installation was investigated. The second phase focused on the development of dynamic properties of CLT panels when reinforced with GFRP. Lay-up configuration and fabric orientation were among the parameters explored.
The results from the experimental program show that reinforcing the panels with steel straps had minimal effect on the ultimate strength, but significant levels of post peak resistance and ductility was achieved. The horizontal straps were able to restrict the failure to small regions and to promote flexural failure by preventing rolling shear failure. It also eliminated flying debris and enhanced the ultimate strength, stiffness as well as ductility. Applying GFRP layers enhanced the overall behaviour of the slab resulting in a significant increase in peak resistance, ductility, and stiffness when compared to the dynamic results of an unretrofitted panel. The post peak resistance was also greatly improved. In particular, applying stacked quadraxial lay-up configuration significantly improved the ductility and resulted in the greatest post peak resistance. The effect of steel straps on damaged and retrofitted was relatively minimal, and only partial recovery of the resistance and the stiffness was achieved. GFRP with full confinement yielded better performance compared to the unretrofitted and undamaged counterpart. More work is needed to quantify the benefits of using GFRP in these applications.
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Branislav, Milanović. "Razvoj hibridnog modela za ocenjivanje životnog ciklusa proizvoda i procesa." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2016. https://www.cris.uns.ac.rs/record.jsf?recordId=100597&source=NDLTD&language=en.
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U okviru doktorske disertacije predstavljen jerazvoj hibridnog modela za ocenjivanje životnog ciklusaproizvoda i procesa. Razvoj hibridnog modela se ogledakroz unapređenje postojećeg metodskog okvira LCA, te jestoga uključio razvoj svih faza LCA, a koje obuhvatajudefinisanje cilja i predmeta, inventar životnog ciklusa,ocenjivanje uticaja životnog ciklusa i interpretacijurezultata. Najznačajnija unapređenja su sprovedena uokviru faza inventara životnog ciklusa i ocenjivanja uticajaživotnog ciklusa. Izmene koje se odnose na načinprikupljanja podataka, su razvijene zbog uključivanjaparametara potrebnih za izračunavanje vrednosti sadržajaeksergije tokova. Unapređenje faze ocenjivanja uticajaživotnog ciklusa se ogleda kroz razvoj originalnog pristupaza izračunavanje ukupne potrošnje eksergije, krozuključivanje dodatne kategorije uticaja, razvijanjeindikatora kategorije uticaja i razvijanje pristupa zaizračunavanje karakterizacionih faktora. Sprovedena je ianaliza postojećih LCIA metoda, radi izbora adekvatnogmetoda u koji će biti uključena dodatna kategorija uticaja,kao i indikator kategorije uticaja, koji zajedno opisujuukupnu potrošnju eksergije tokom čitavog životnogciklusa. Takođe, prilikom razvoja kategorije uticaja supoštovani određeni kriterijumi, koje ona mora da zadovoljida bi mogla biti adekvatno uključena u odabrani LCIAmetod. Pored toga, bitan deo unapređenja ocenjivanjauticaja životnog ciklusa, leži u razvoju proračunakarakterizacionih faktora. Razvijena dodatna kategorijauticaja nazvana je Ukupna potrošnja eksergije - UPE, aizražava se preko indikatora MJex. LCIA metod koji jeodabran na osnovu SWOT analize u koji je ova dodatnakategorija uticaja uključena je CML metod. Postavljenihibridni metodski okvir posmatra kompletan životni ciklus,ali i svaki od jediničnih procesa koji uključuju elementarnetokove, odnosno tokove uzete iz prirodnog sistema bezdodatne obrade, kao i tokove proizvoda, odnosno tokovekoji su na neki način izmenjeni od strane pojedinihantropogenih sistema. Izračunavanje sadržaja eksergije ikarakterizacionih faktora je sprovedeno kako zaelementarne tokove tako i za tokove proizvoda.Funkcionalnost i praktična primenljivost razvijenoghibridnog modela je verifikovana na dva primera, koji suobuvatili proizvodnju laminatnog parketa i međusobnukomparaciju hibridnih baznih predajničkih stanica ikonvencionalnih baznih predajničkih stanica. Dobijenirezultati daju jednu zaista detaljniju i širu sliku mehanizmanastanka i izvora negativnih uticaja tokom životnog ciklusaposmatranih industrijskih sistema. Time je potvrđenanjegovu praktična primenljivost, kao i ukupni ciljistraživanja. Rezultati istraživanja realizovani u okvirudoktorske disertacije, u opštem smislu, daju doprinosstvaranju osnove za izdradnju puta ka razvoju i proizvodnjiodrživih proizvoda i procesa. Razvijeni hibridni model zaocenjivanje životnog ciklusa proizvoda i procesa pružadodatne informacije, koje mogu biti korisne u procesudonošenja odluka na svim nivoima, kako u industriji tako iu državnim institucijama.This PhD thesis presented the development of ahybrid model for life cycle assessment of products andprocesses. The development of a hybrid model includes theimprovement of the existing methodological LCAframework, and therefore of all phases of the LCA:definition of goal and scope, inventory analysis, life cycleimpact assessment and interpretation. The most significantimprovements have been made within the inventoryanalysis and life cycle impact assessment phases.Improvement have been made in relation to the method ofdata collection, due to the inclusion of parameters forcalculation of the exergy content of in- and output flows.Improvement of the life cycle impact assessment phase isreflected through the development of original approach forcalculating the total consumption of exergy, through theinclusion of additional impact category, development ofindicator for impact category and development of methodfor calculation of characterization factors. The analysis ofexisting LCIA methods was performed, in order to choosethe appropriate method that will incorporate this additionalimpact category, as well as an impact category indicator,which together should describe the total consumption ofexergy throughout the entire life cycle. Further,development of this impact category have been compliedwith certain criteria which it must meet in order to beproperly incorporated in the chosen LCIA method. Besidesthis, an important part of improvement of the life cycleimpact assessment is the development of method forcalculation of characterization factors. Developedadditional impact category is named Total exergyconsumption, and it's expressed through indicator of MJex.LCIA method that is chosen based on the performedSWOT analysis and which incorporated this additionalimpact category is CML method. Developed hybridmethodological framework takes into account the entire lifecycle, and each of the unit processes that involveselementary flows (flows taken from the natural systemwithout any further processing), as well as product flows(flows that are in some way altered by certainanthropogenic system). Calculation of exergy andcharacterization factors was performed for both elementaryand product flows.Functionality and practical applicability of thedeveloped hybrid model was verified through two casestudies, which are the production of laminate parquetflooring and comparison of hybrid base transceiver stationsand conventional base transceiver stations. The obtainedresults provided more detailed and more broader insight ofthe mechanism of the generation and source of negativeimpacts throughout the life cycle of observed industrialsystems. Thus, the practical applicability of the developedhybrid model and goal of the research have beenconfirmed. The results of the research contribute tocreation of the foundation for designing a path towardsdevelopment and manufacturing of sustainable productsand processes. The developed hybrid model for the lifecycle assessment of products and processes providesadditional information that may be useful in decisionmakingprocess at all levels, within both industry andgovernment institutions.
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Mezeiro, Rafaela Maria Marques. "Construir em Madeira aplicabilidade de painéis CLT em habitação de média densidade em Portugal." Master's thesis, Universidade de Lisboa, Faculdade de Arquitetura, 2018. http://hdl.handle.net/10400.5/18088.
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Dissertação de Mestrado Integrado em Arquitetura, com a especialização em Arquitetura apresentada na Faculdade de Arquitetura da Universidade de Lisboa para obtenção do grau de Mestre.Serve o presente trabalho para estudar a viabilidade da aplicação do sistema construtivo de painéis de madeira de Cross Laminated Timber - CLT, na construção ou recuperação de um edifício de habitação de média densidade em Portugal, na cidade de Lisboa. Os painéis de CLT são peças de madeira associadas a um processo construtivo inovador, com uma considerável capacidade de suportar cargas aplicadas, principalmente quando comparado com sistemas construtivos convencionais. Neste tipo de estruturas de CLT os elementos que a constituem comportam-se como painéis, em que o transporte das forças é feito bidireccionalmente. Considerou-se a elaboração deste trabalho atendendo às preocupações relacionadas com um tema da actualidade, nomeadamente as alterações climáticas. Ao nível da arquitectura, uma das formas de reduzir o impacto ambiental que a construção provoca é por exemplo através da utilização da madeira, que por sua vez tem a capacidade de armazenar dióxido de carbono, um dos principais gases emitidos para a atmosfera com efeito de estufa. Ao potenciar o uso da madeira, está-se por uma lado a dinamizar o sector madeireiro, mas também por outro lado a contribuir para a diminuição da pegada ecológica. Na realidade, com o aumento da utilização da madeira poder-se-á eventualmente, verificar-se uma maior necessidade do aumento da fileira, significando portanto que quantas mais árvores forem plantadas maior a quantidade de CO2 poderá ser retirada da atmosfera, desta forma também poderá surgir a necessidade de criar diferentes políticas de gestão e manutenção florestal com esta utilização em vista. Atendendo às propriedades físicas e mecânicas da madeira considerou-se importante abordar o tema da pré-fabricação de peças de madeira. Por ser um material dúctil, a madeira permite a normalização de vários tipos de produtos que por sua vez podem ser aplicados na construção de casas modulares, em que um dos principais objectivos deste tipo de construção está relacionado com a regularização das dimensões da construção de modo a estabelecer um módulo padrão como unidade de medida de referência, optimizando-se o processo de pré-fabricação e montagem do edifício no local. Por outro lado este é um tipo de construção que obedece a medidas passivas, que por sua vez pressupõe poupanças, ou até mesmo reduções significativas do consumo de energia do próprio edifício.
ABSTRACT: The present work aims to study applicability of the use of the Cross Laminated Timber – CLT construction system for new construction and rehabilitation of medium density housing in Portugal, in the city of Lisbon. The CLT panels are pieces of wood associated with an innovative construction process, with a considerable loading capacity, especially when compared with traditional constructive systems. In this type of CLT structures the elements consist of panels, in which the force transport is made bidirectionally. The elaboration of this work was considered taking into account the concerns related to a current theme, namely climate change. In architecture one of the ways to reduce the environmental impact that the construction causes is for example through the use of wood, since this material has the capacity to store carbon dioxide, a green house effect gas. By enhancing the use of wood, on the one hand, the timber industry could become more dynamic while also contributing to the reduction of green house effect. In fact, with increasing use of wood there will also be a greater need to plant trees, impling that the more trees that are planted the more CO2 that is withdrawn from the atmosphere, this could also create the need to create a different forest management and maintenance policies. Considering the physical and mechanical properties of wood, it was considered important to address the pre-fabrication of wood pieces. Because it is a ductile material, wood allows the standardization of several types of products which in turn can be applied in the construction of modular houses, in which one of the main objectives of this type of construction is related to the regularization of the dimensions of the construction with the purpose to establish a standard module as a reference unit of measurement, optimizing the pre-fabrication and assembly process of the building on site. On the other hand this is a type of construction that obeys passive requirements, which in turn supposes savings, or even significant reductions in the energy consumption of the building itself.
N/A
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Řeháček, Jakub. "Výstavní pavilon." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227320.
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The thesis deals with the design and review of the supporting structure of the exhibition pavilion in the suburb of Brno. The design is shaped dome built over the octagonal floor plan with eight lateral niches. The pavilion is 30m wide and 8 meters tall.
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Acosta, Caio Cesar Veloso. "Tabuleiro laminado protendido de Pinus sp. com cordoalhas engraxadas." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-27042015-112922/.
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O tabuleiro laminado protendido é uma composição de peças interligadas por uma tensão de compressão aplicada perpendicularmente às lâminas de madeira. Para aplicar tal tensão, são usados elementos de aço tensionados e a cordoalha engraxada aparece no cenário atual como um material econômico para tabuleiros laminados protendidos, em substituição às barras dywidag, que são comumente utilizadas neste tipo de estrutura em outros países. O funcionamento mecânico do tabuleiro é caracterizado como uma placa ortotrópica, e este trabalho visou determinar as relações entre as constantes elásticas do tabuleiro com a utilização da cordoalha engraxada. Foram analisadas também as perdas de protensão ocorridas ao longo do tempo, causadas pela fluência e relaxação dos materiais e, a partir dos resultados, foi proposta uma equação para determinação teórica da perda de protensão nos tabuleiros. O estudo experimental foi realizado em um modelo em escala reduzida construído no LaMEM (Laboratório de Madeiras e Estruturas de Madeira) para determinar as constantes elásticas e as perdas de protensão. Ao fim do trabalho são apresentados os resultados e comparações com estudos anteriores; também foi confeccionado um Manual de Boa Execução para Tabuleiros Laminados Protendidos de Madeira com Cordoalha engraxada.The stress-laminated bridge deck is a composition of parts, interconnected by compression stress, perpendicularly applied to the wood laminate. In order to apply such stress, stressed steel elements are used, as well as the greased wire rope, which comes along in the current scenario as an economic material for stress-laminated bridge decks, replacing the dywidag bars, commonly used in this sort of structure in other countries. This bridge deck mechanic function is characterized as an orthotropic plate, and this paper aimed at determining the relation among the decks elastic constants with the greased wire rope. Another analyzed point is the stress loss occurred through time, caused by material creep and relaxation, and, through the results, an equation for the decks stress loss theoretical determination was proposed. The experimental study was developed in a reduced scale built in LaMEM (Laboratório de Madeiras e Estruturas de Madeira) to determine the elastic constants and the stress loss. The results and comparisons with previous studies are presented by the end of this paper; In addition, a handbook of Proper Execution for Stress-laminated Wood Bridge Decks with Greased Wire Rope was developed.
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BERTAGNA, SERENA. "Soluzioni Strutturali per la Sostenibilità Ambientale di Barche in Legno." Doctoral thesis, Università degli Studi di Trieste, 2022. http://hdl.handle.net/11368/3010838.
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Negli anni recenti, l’importanza di implementare soluzioni più verdi e sostenibili, unita ai principi base del life cycle assessment, è cresciuta esponenzialmente in ogni settore industriale. In questo contesto, la cantieristica nautica non fa eccezione, dal momento che rappresenta una significativa fonte di inquinamento ambientale a causa della grande produzione coinvolta. In aggiunta, la cantieristica nautica stessa gioca un ruolo strategico come portatore di innovazione e può supportare lo scopo di innovare processi tecnologici anche nel settore della cantieristica navale. In particolare, per ottenere i traguardi verdi che riguardano i materiali, è chiaro come i compositi fibro-rinforzati comunemente usati per la costruzione di imbarcazioni presentino svantaggi legati al loro impatto ambientale e alle procedure di smaltimento. D’altro canto, l’estrema importanza di assicurare robustezza e durabilità, combinata con un buon rapporto peso/resistenza, è un altro fattore chiave per la scelta del materiale più appropriato. Di conseguenza, alternative innovative in grado di combinare sia sostenibilità che capacità di resistenza devono essere identificate. In questo contesto, le tecnologie di costruzione basate sul legno come lo strip-planking rappresentano soluzioni promettenti, dato che uniscono sia l’utilizzo di un materiale dalla crescita naturale che la possibilità di ottenere strutture rifinite e robuste. Tuttavia, queste implicano l’adesione del legno attraverso adesivi epossidici convenzionali; quindi, per incrementare l’eco-friendliness del prodotto finale, devono essere investigati adesivi bio-based innovativi. Inoltre, è fondamentale considerare che i giunti adesivi sono solitamente punti deboli delle strutture, perciò la selezione degli adesivi deve essere basata anche sulle loro effettive capacità di incollaggio.
Nella presente ricerca è presentata la validazione per l’uso strutturale di due adesivi bio-based accoppiati con essenze di legno comunemente utilizzate nella cantieristica nautica. In primo luogo, è stata effettuata una campagna sperimentale mirata a testare provini in legno incollato con adesivi bio-based per ottenere risultati sulle loro performance meccaniche. I test sperimentali sono stati finanziati con un Innovation Voucher del progetto Interreg ADRION BLUE_BOOST. Secondariamente, una metodologia basata sul metodo agli elementi finiti è stata messa a punto e applicata ai modelli dei provini sfruttando i dati presenti nelle schede tecniche degli adesivi bio-based e delle essenze di legno. Sia l’approccio sperimentale che quello numerico hanno mostrato l’adeguatezza degli adesivi bio-based per strutture in legno incollato, e hanno posto le basi per i prossimi sviluppi della ricerca mirata a ottenere una maggiore sostenibilità nelle costruzioni nautiche.Over recent years, the importance of implementing greener and sustainable solutions merged with the basic principles of life cycle assessment has exponentially grown in each industrial sector. In this framework, boatbuilding is no exception, since it represents a significant source of environmental pollution due to the massive production involved. Furthermore, boatbuilding itself plays a strategic role as innovation carrier and can assist in chasing the aim of innovating technology processes also in the shipbuilding sector. In particular, in order to pursue the green achievements involving materials, it is clear that the fibre-reinforced composites commonly used for boat constructions present disadvantages related to their environmental impact and disposal procedures. On the other hand, the extreme importance of ensuring robustness and durability, combined with a good weight/resistance ratio, is another key factor when choosing the most proper material. As a result, innovative alternatives able to combine both sustainability and strength capacity must be identified. In this framework, construction technologies based on wood such as strip-planking represent promising solutions, as they merge the use of a natural-grown material and the possibility of attaining refined and strong structures. However, they imply wood bonding through conventional epoxy adhesives; therefore, to increase the global eco-friendliness of the final product, innovative bio-based adhesives must be investigated. Moreover, it is to consider that adhesive joints generally are weak spots in structures, so the selection of adhesives must be based also on their effective bonding performances. In the present research, the validation for structural use of two bio-based adhesives coupled with wood essences commonly used in boatbuilding is presented. Firstly, in order to obtain results regarding mechanical performances, an experimental campaign aimed at testing wood specimens glued with bio-based adhesives was carried out. The experimental tests were funded with the Innovation Voucher Scheme of the Interreg ADRION BLUE_BOOST project. Secondly, a FEM-based methodology was set up and applied to specimen’s models by using the data present in the technical datasheets of both bio-based adhesives and wood essences. Both the experimental and numerical approaches shown the suitability of bio-based adhesives for bonded wooden structures, and laid the basis for the next research developments in order to attain a greater sustainability in boatbuilding.
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RIU, RICCARDO. "Caratterizzazione di pannelli x-lam in pino marittimo sardo." Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266697.
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Background and Purpose: The aim of this work is to present the idea of a short procurement chain of timber as a means to provide an increased value to Sardinian forests. It is based on the evidence that timber buildings are increasingly useful for a number of reasons including sustainability, the speed of erection, and excellent structural performance. However, most of the timber currently used in Sardinia is imported from outside this area. The idea is to use the best part of locally-grown trees to produce timber boards, while all the remaining part of the tree including the production waste is used as biomass for energy production. Important issues to address are the generally low mechanical properties of timber from locally-grown Sardinia trees such as Maritime Pine, which would make some wood-based products like glue-laminated timber not technically viable. Cross-laminated timber panels seems to be a possible solution to this problem because this wood-based product is manufactured in such a way that even with low-quality timber boards it is possible to obtain a medium quality panel. The panel is made of layers of timber boards with the adjacent layers glued under pressure at a right angle. Another issue is the need to grade the local timber, for which a number of specimens must be tested on destruction in order to identify a visual or a machine stress grading procedure. Last but not least, the panels must be tested on destruction to correlate their mechanical properties to the properties of the boards.
Materials and Method: the research has been developed through the following steps: 1) two maritime pine plantations with stands suitable for logging and processing were identified, extensively surveyed and sampled. On selected standing trees, based on measurements taken at different heights, the first preliminary grading was applied by sorting for structural and energy use. 2) Trees were harvested by a local company and the logs were finally assorted based on their size and their external defects. 3) The logs were then transported to the local sawmill, where different boards size required to build the grading rules and to produce the CLT panels were cut. Each board was then subjected to a non-destructive measurement of the Modulus of Elasticity using acoustic tool for measuring stress wave velocity (Viscan-Microtec) 4). After kiln drying, the required boards (approximately 840) were subjected to non-destructive measurements of their physical properties (density, humidity, defects etc.) using the machine purposely developed by Microtec. The aim was the calibration of this machine in order to enable the machine strength grading of Sardinia maritime pine. 5) The required boards were visually characterized and then tested to destruction in order to measure their strength and correlate this values to the presence of defects such as knot diameters and positions, grain deviations, etc. 6) Based on the results of phases 4 and 5, the visual and machine based grading rule for Sardinia Maritime Pine have been developed. 7) By applying the newly developed grading rules, some boards
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have been selected among the available ones and used for the production of some prototypes of CLT panels. 8) In order to determine the structural performance, 68 panel have been tested to destruction. Testing was carried out in accordance with EN 408 on specimens with a span to depth ratio equal to 18 to determine the bending strength and stiffness, and on specimens with span to depth ratio equal to 9 to determine the shear strength. A number of different methods exist for the analysis and design of CLT elements, including the Shear Analogy Method and the Mechanically Jointed Beams Theory (Gamma Method). These methods have been considered in this study and a relative comparison have been presented in order to determine which method is most suitable when considering CLT formed using Sardinian grown timber..
Results: It was found that Maritime Pine as structural material is limited by stiffness rather than strength or density. The effective bending stiffness of CLT is a measure of the material stiffness in relation to the cross sectional build-up of the panel. To be competitive on the market, a Sardinian CLT product will have to compete with imported CLT panels, which are usually made from C24 graded material (spruce). In most cases this is simply because the C24 material is widely available on the market rather than a specification from the designer. The performance of panels made of Maritime Pine boards has been compared directly with that of imported products, demonstrating that an increase in the Sardinian panel depth of just 15% is sufficient to match the stiffness of the imported panels, which is the most important design property.
Conclusions: This work lays the foundation for the development of a short procurement chain of wood in Sardinia. The EDENSO project developed in parallel to this doctorate study is still in progress and further tests on maritime pine CLT panels are planned. A short procurement chain of timber is a possible means to create job opportunities and reduce depopulation, particularly important in some area of the island. By adding value to the forests by means of timber production used in prefabricated components employed in low-rise timber buildings, it is also possible to improve forest management and even extend forested areas, which have many positive effects on the environment, the landscape and the reduction of hydrogeological hazard.
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Icimoto, Felipe Hideyoshi. "Dormentes de Madeira Lamelada Colada (MLC) reforçados com tecidos de fibra de vidro." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-06082018-104852/.
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A primeira ferrovia no Brasil foi inaugurada em abril de 1854 pelo Barão de Mauá com 14,5 km de extensão. Atualmente o país possui 27980 km de ferrovias e esse modal tem participação em 25% na matriz brasileira de transporte de carga. Um dos componentes mais importantes da superestrutura ferroviária é o dormente, que pode ser fabricado utilizando-se diversos materiais como a tradicional madeira, que tem uso histórico e consagrado para esta aplicação estrutural, além do concreto e do aço, e mais recentemente, os compósitos poliméricos. As madeiras com maior tradição no uso em dormentes provêm de espécies nativas de alta densidade com consequente elevada resistência mecânica e durabilidade natural. Porém, devido às restrições impostas à extração destas espécies nativas, houve forte redução de sua oferta, sendo forçada sua substituição por madeira de florestas plantadas de eucalipto de alta densidade como E. citriodora, E. paniculata e E. tereticornis. Contudo, dormentes de diferentes espécies de eucalipto, pouco adequadas para esse uso, estão apresentando muitos problemas em via. Outra madeira de florestas plantadas muito utilizada no Brasil é o pinus e uma aplicação muito nobre para este tipo de madeira é a produção de elementos estruturais em Madeira Lamelada Colada (MLC). O objetivo do presente trabalho foi o estudo teórico e experimental de dormentes de MLC confeccionados com madeiras de Pinus spp. tratadas com CCA, coladas com adesivo poliuretano, e reforçados com tecido bidirecional de fibra de vidro. Para tanto, realizou-se um estudo teórico e experimental a partir de ensaios estáticos e dinâmicos tendo-se em vista a necessidade de utilização de novas espécies de madeira de reflorestamento com resistência adequada a tal finalidade. Os resultados obtidos nos ensaios realizados de acordo com a normalização vigente atestaram a viabilidade técnica da utilização de dormentes em MLC de Pinus spp. reforçados com fibra de vidro desde que sejam realizadas as classificações visual e mecânica das lamelas, para a obtenção das propriedades de resistência e rigidez necessárias.Brazil\'s first railroad was inaugurated in April, 1854 by Barão de Mauá with 14.5 km of extension. Currently the country has 27980 km of railways, and this transportation modal has 25% participation in the Brazilian freight transport matrix. One of the most important elements of railway superstructure is the sleeper (or tie), which can be manufactured from several materials, such as the traditional wood, that has historical and well-established use for this structural application, as well as concrete, steel, and recently, polymer composites. The classic sleeper is made by timber from native species of high density with consequent high mechanical strength and natural durability. However, due to the restrictions imposed on the extraction of these native species, there was a strong reduction in their supply, being forced to replace them with timber from high density eucalyptus planted forests such as E. citriodora, E. paniculata and E. tereticornis. Therefore, sleepers from different eucalyptus species, that are not suitable for this use, are presenting many problems on railroad. Another wood from planted forests widely used in Brazil is the pinus, and a very noble application for this kind of wood is the production of structural elements in Glued Laminated Timber (Glulam). The aim of this work was the theoretical and experimental study based on static and dynamic tests of Glulam sleepers manufactured using Pinus spp. treated with CCA, glued with polyurethane adhesive, and reinforced with bidirectional fiberglass fabric. For that, a theoretical and experimental study was carried out from static and dynamic tests, considering the potential use of new reforestation species of wood with suitable strength to this purpose. The results show technical feasibility in the use of Glulam sleepers made with Pinus spp. reinforced with fiberglass provided that visual and mechanical classifications of the timber are realized, in order to obtain the required strength and stiffness properties.
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Uherka, Pavel. "Tepelně-vlhkostní analýza konstrukcí masivních dřevostaveb." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240341.
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This thesis deals with massive wooden buildings especially with regard to the current approach to their design, assessment and approval. In this thesis are shown future possibilities of development of traditional wooden buildings with regard to current thermal technical requirements. Theoretical considerations are then compared with measurements which were performed on massive wooden wall samples.