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1
Franke, Bettina, Florian Scharmacher und Andreas Müller. „Assessment of the Glue-Line Quality in Glued Laminated Timber Structures“. Advanced Materials Research 778 (September 2013): 424–31. http://dx.doi.org/10.4028/www.scientific.net/amr.778.424.
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Timber constructions with glulam members have regularly to be proofed for their performance to avoid structural collapse. For the assessment of glued laminated timber, it is important to know reliable methods and criteria. The requirements given in standard EN 386:2001 are valid for the quality control of the glulam production. The use and application of these two different methods at existing timber structures were investigated and discussed. The experimental test series comprise different adhesives as well as specimen from new material and existing structures. Problems and issues noted during the test series and analyses of the results are discussed. The correlations found provide advice for the assessment of existing structures.
2
Okafor, Kingsley Kenechukwu, und Celestine Akaolisa Ezeagu. „The Analysis of Bending Stiffness and Strength of Glue Laminated Nigerian Timber“. European Journal of Engineering Research and Science 5, Nr. 2 (25.02.2020): 196–200. http://dx.doi.org/10.24018/ejers.2020.5.2.1699.
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An analysis into the flexural strength of solid and laminated timber specimens under working conditions was conducted. Five hardwoods and five softwoods were investigated, namely: Mansonia, Mahogany, Orji, Ukpi, Ufi mmanu, White Afara, Owen, Melina, Akpu and Ubia. The dimensions of the wood specimens are 100mm×50mm×20mm. The wood samples were tested for flexural strength using a Universal Testing Tensile Machine. The results obtained shows that Owen has the highest ultimate wood strength of 46.806N/mm² for the softwood glulam. Ukpi has the highest wood strength of 73.375N/mm² for the hardwood glulam, and highest MOE at 2412.93N/mm². Akpu recorded the weakest sample with bending strength values for glulam at 11.929 N/mm². Comparisons of strength were made to their respective solid timbers. Failure modes were analyzed. The study therefore demonstrates that the timber species used can be engineered to load bearing glulam structural elements using polyurethane adhesive glue without severe loss of strength.
3
Jihan Abd Malek, Nor, Rohana Hassan, Azmi Ibrahim und Mohammed Hasan Alhebshi. „Shear Block Test Performance of Melunak and Mengkulang“. International Journal of Engineering & Technology 7, Nr. 3.11 (21.07.2018): 210. http://dx.doi.org/10.14419/ijet.v7i3.11.15963.
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This paper presented results of shear block test performance of tropical glued-laminated timber (glulam) from species of melunak and mengkulang. Glulam blocks were manufactured in accordance with MS758:2001. The shear block test for glue lines and the shear strength tests of melunak and mengkulang were conducted and evaluated in accordance with BS EN 14080:2013. Melunak and mengkulang produced average shear strength values of 10.62 N/mm2 and 8.19 N/mm2, respectively. In terms of wood and glue failure percentage, the results showed that melunak and mengkulang were mainly failed due to wood surface area and not due to the glue lamination in which both melunak and mengkulang showed a good bonding performance.
4
Karacabeyli, E., H. Fraser und W. Deacon. „Lateral and withdrawal load resistance of glulam rivet connections made with sawn timber“. Canadian Journal of Civil Engineering 25, Nr. 1 (01.01.1998): 128–38. http://dx.doi.org/10.1139/l97-070.
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The efficiency of glulam rivets has made them one of the most suitable connectors in heavy timber construction utilizing glued-laminated timber (glulam) members. Starting with the 1994 version of the CSA Standard for Engineering Design in Wood, design procedures are also available for the use of glulam rivet connections with sawn timbers. In the course of formulating these design provisions, several series of lateral resistance and withdrawal tests were performed using glulam rivets with sawn timbers to study the effects of material (sawn timber versus glulam), species, loading type and direction, environmental conditions, density, waiting period between assembly and test, pre-drilling, and plate thickness. The newly added design provisions increase structural engineers' choice of fastening systems in timber construction.Key words: glulam rivets, fasteners, connections, timber.
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Klapálek, Pavel, Lenka Melzerová und Tomáš Plachy. „Pulse Method Used for Non-Destructive Assessment of Glued Laminated Timber Beams“. Applied Mechanics and Materials 827 (Februar 2016): 231–34. http://dx.doi.org/10.4028/www.scientific.net/amm.827.231.
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This text is focused on GLULAM (glued laminated timber) beams and determination of their properties. This text is mainly focused just on part of more complex research of glued laminated timber beams. This text is focused on pulse method, which is used to determine the dynamic modulus of elasticity of GLULAM beams. This text will describe how the pulse method works, with basic description, describes the tested material and compare the results of testing. In the conclusion we discuss the results, make conclusions and describe the way of our further research of glued laminated timber beams.
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Buchanan, A. H., und R. H. Fairweather. „Seismic design of glulam structures“. Bulletin of the New Zealand Society for Earthquake Engineering 26, Nr. 4 (31.12.1993): 415–36. http://dx.doi.org/10.5459/bnzsee.26.4.415-436.
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This paper gives an overview of the seismic performance of glue laminated (glulam) timber frame buildings. It describes the wide range of connections that can be used in glulam frames, for both single storey and multi-storey buildings, with particular reference to seismic loading.
Several new connections incorporating epoxied steel bars are described in detail. Testing of these connections under simulated seismic loading is reported, with recommendations for seismic design.
A design procedure is given for low rise multi-storey glulam frame buildings.
7
Keenan, F. J., J. Kryla und B. Kyokong. „Shear strength of spruce glued—laminated timber beams“. Canadian Journal of Civil Engineering 12, Nr. 3 (01.09.1985): 661–72. http://dx.doi.org/10.1139/l85-073.
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The effect of size on longitudinal shear strength has been well established for Douglas-fir glued–laminated (glulam) timber beams. The present study examined whether this phenomenon exists in glulam beams made of spruce. The experiment consisted of three projects in which beams of various sizes were tested under concentrated mid-span load. The project A beams had clear spruce webs and white elm flanges with cross-sectional dimensions varying from 25 × 25 mm to 75 × 75 mm. The project B beams had spruce glulam webs with Douglas-fir flanges; cross sections ranged from 20 × 100 mm to 90 × 200 mm. In project C, three groups of 10 replications of commercially representative sizes of glulam beams were made from stiffness-rated spruce–pine–fir lumber. The beam cross sections were 76 × 200 mm, 76 × 400 mm, and 127 × 400 mm.The results indicated that depth, width, and shear plane had significant effects on the longitudinal shear strength of the beams in project A. Depth, width, and shear span of the small glulam beams in project B also had highly significant effects on shear strength. However, no effects of depth and width on the shear strength of glulam beams in project C were found. Regression analysis showed no dependence of shear strength on sheared volume for the beams of all three projects. The three-parameter Weibull model also failed to predict the near-minimum shear strength of spruce glulam beams. The results suggested that the lower-bound shear strength of spruce glulam beams is a constant (regardless of beam volume) and could be used as a single characteristic value for glulam design in shear. Further review of published data indicates that this may also be the case for Douglas-fir glulam but with a lower characteristic value than for spruce.
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Karacabeyli, Erol, und Henley Fraser. „Short-term strength of glulam rivet connections made with spruce and Douglas-fir glulam and Douglas-fir solid timber“. Canadian Journal of Civil Engineering 17, Nr. 2 (01.04.1990): 166–72. http://dx.doi.org/10.1139/l90-021.
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The 1984 edition of the Canadian Standards Association Standard 086 restricts the use of glulam rivets to Douglas-fir– larch glued-laminated timber (glulam) only. This study, undertaken in order to extend the use of glulam rivets to both spruce glulam and solid timber, presents the results from the short-term ramp testing of 33 glulam rivet connections assembled using white spruce and Douglas-fir glulam beams and Douglas-fir solid wood joists. Half of these connections were tested to failure with load applied parallel to the grain of the wood member; the other half were tested with load applied perpendicular to the grain. A species factor of 0.80 is recommended for application to the design values of Douglas-fir–larch glulam rivet connections in order to obtain values for spruce glulam rivet conne-ctions. Also, small (less than 4%) differences were found between the lateral load-carrying capacities of glulam rivet connections made with Douglas-fir glulam and connections made with Douglas-fir solid timber free from major checks and (or) splits. To provide theoretical representations of the load–slip curves of the experimental treatment groups, an exponential function was fitted to the test data. Key words: glulam rivet, timber engineering, fasteners, nails, glued-laminated, wood connectors.
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Vodiannikov, Mikhail, und Galina Kashevarova. „Composite Solutions for Glulam Joints“. Key Engineering Materials 801 (Mai 2019): 47–52. http://dx.doi.org/10.4028/www.scientific.net/kem.801.47.
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The current level of the development of composite materials allows producing laminate structures with the desired properties. The application of supercomputer calculation and software systems, numerical modeling methods using finite elements enables the design and analysis of such structures. This article deals with design and calculation methods; the results of the full-scale tests of the joints of glued laminated timber with carbon fiber dowel pins and plates are presented. An overview of the behavior of such structures in corrosive environment and the comparative analysis with traditional steel components are also presented herein. Advantages and disadvantages of glulam joints where composite materials are used are noted. Examples of the joint use of composi\te materials and timber in Russia and internationally are given. Conclusions about the possibilities and ways of using composite materials in the design of wide-spanned glued timber structures are drawn.
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Zhou, Xian Yan, Qian Wang, Zhi Feng Wang, Zhong Feng Zhang und Lei Cao. „Research on Mechanical Properties and Engineering Application of Modern Timber Structure“. Advanced Materials Research 639-640 (Januar 2013): 105–10. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.105.
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Modern timber structure holds many virtues in the fields of construction, such as energy-saving, green, aesthetics, ect, superior to concrete and steel bridge. Meanwhile，it is the mechanical properties of timber structure that have been attracted much attention compared with other structures. It is not only glue laminated timber(glulam) but also tri-axial grids sandwich panels（TGSP）satisfy high load-bearing capacity and long-span requirements of modern timber bridge. As two essential parts of elements used as columns，decks in modern timber structure, glulam column had more full hysteretic curve with high energy-consuming ability and good seismic performance under reciprocating load was showed in this paper , and excellent compression property and bending property of TGSP were also studied . Finally, an engineering application was introduced. Filling the domestic gaps in bridge construction successfully, the first modern timber bridge in China has remarkable significant and greatly boosts the development of timber work.
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Kusnindar, Sri Murni Dewi, Agoes Soehardjono und Wisnumurti. „Performance of glue laminated timber beams composed of sengon wood (Albizia falcatara) and coconut wood (Cocos nucifera) with nylon-threads reinforcement“. MATEC Web of Conferences 195 (2018): 02029. http://dx.doi.org/10.1051/matecconf/201819502029.
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This paper aims to describe the performance of mix-glue laminated timber beams that are given a nylon strapping as external reinforcement with the three-point bending test to three groups of beams based on the span-to-depth ratio, i.e.: G11, G8, and G5 groups. Each group consists of three types of lamination compositions, namely: Type I, whole lamination consists of sengon wood; Type II, the placement of the coconut wood lamination as the outermost; Type III, similar to type II with added nylon straps with a distance of 5 mm. The bending test results show differences in elastic modulus, flexural strength and shear strength of the glue-laminated timber beams. Based on the comparison of glulam beams consisting of six laminations of sengon wood it was found that the placement of the coconut wood as the outermost lamination succeeded in increasing the elastic modulus, the flexural and shear strength of beams by 28%, 13%, and 34%, respectively. In addition, the reinforcement with nylon straps results in the modulus of elasticity, bending and shear strength of glulam to increase by by 41%, 2%, and 49% respectively.
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Hampson, J. A., H. G. L. Prion und F. Lam. „The effect of end distance on the moment resistance of timber rivet connections“. Canadian Journal of Civil Engineering 30, Nr. 5 (01.10.2003): 945–48. http://dx.doi.org/10.1139/l03-050.
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The results of an experimental study on moment connections with timber rivets are reported. The end distance for a four-rivet moment connection is varied in an attempt to determine the effect on the moment capacity and the failure mode. Varying the end distance did not seem to induce the occurrence of a brittle failure mode, but a slight reduction in the strength and stiffness of joint was observed. This was confirmed for specimens made with glued-laminated timber (glulam), laminated-veneer lumber (LVL), and parallel-strand lumber (PSL).Key words: wood, timber, moment, connection, brittle, end distance, glulam and rivet.
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Terezo, Rodrigo Figueiredo, Talitha Oliveira Rosa, Francisco Raphael Cabral Furtado, Camilla Gabriela Melo Ampessan, Alexsandro Bayestorff Cunha und Angela Do Valle. „SCARF JOINTS IN GLUED LAMINATED TIMBER OF PARICÁ“. FLORESTA 51, Nr. 3 (22.06.2021): 713. http://dx.doi.org/10.5380/rf.v51i3.72445.
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Glued Laminated Timber (GLULAM) is manufactured by joining wood lamellae glued in parallel to each other. GLULAM with larger longitudinal dimensions can be obtained by gluing the tops of two wood lamellae. The gluing of the tops can be done using wedge-shaped scarf joints. However, the joints produce a discontinuity in the wood, being areas considered as susceptible to rupture. In this way, the objectives were to evaluate four slopes (1:6; 1:8; 1:10 and 1:12) in scarf joints of Schizolobium parahyba var. amazonicum timber for use with structural purposes; and glued laminated timber beams – GLULAM manufactured with the scarf joint with the best performance by the modulus of elasticity – MOE (theoretical and analytical MOE values). Each laminated timber used to produce the test specimens was classified by visual inspection that aimed at the absence of defects, such as knots. The test specimens were adapted to the four-point static bending test and to the tensile strength test in parallel to the grain direction, in accordance to the NBR 7190 (1997). The slope of 1:12 showed the best results, while the slope of 1:6 presented the lowest results when compared with the control. The beams of 5 x 9.5 x 220 cm, composed of joints with slopes of 1:12, showed MOE values statistically equal to those of beams without joints. The scarf joint proved to be an alternative for use in glulam beams of paricá, as it presents stiffness and strength comparable with those of beams without a joint.
14
Cheng, Xiao Wu, Wei Qing Liu, Wei Dong Lu, Hui Feng Yang und Kong Yue. „Engineering Application of Glued Laminated Timber Structures in China“. Applied Mechanics and Materials 71-78 (Juli 2011): 577–82. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.577.
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An overall outline is given for the development of the glued laminated timber structures in China. Different types of glulam structures built in recent years, such as gymnasium, bridges, public buildings, traditional architecture, landscape structures have been discussed. During the development of glulam structure in the future, raising design and produce level will be the most important question we confront and should be settled.
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Dias, André M. A., Carlos E. J. Martins und Alfredo M. P. G. Dias. „Influence of the treatment phase on the gluing performance of glued laminated timber“. BioResources 15, Nr. 3 (03.06.2020): 5725–36. http://dx.doi.org/10.15376/biores.15.3.5725-5736.
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Glued laminated timber (glulam) is a wood-based product with frequent use in timber construction. Maritime pine (Pinus pinaster Ait.) is a species suitable for glulam production and is available with abundance in Portuguese forests. This study assessed the influence of the phase in which the preservative treatment is applied in the surface bonding performance. Several elements were produced considering different treatment scenarios: timber without treatment, timber treated before gluing, and timber treated after gluing. The bonding quality was tested by both shear strength and delamination tests, following the indications given in EN 14080 (2013). Glulam elements treated after gluing (TAG) presented less delamination when compared with the ones treated before gluing (TBG). However, TBG elements presented higher shear strength values than TAG elements. Despite the recorded differences, all the considered sets performed adequately both for delamination and shear strength tests.
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Hassan, Osama A. B., und Christopher Johansson. „Glued laminated timber and steel beams“. Journal of Engineering, Design and Technology 16, Nr. 3 (04.06.2018): 398–417. http://dx.doi.org/10.1108/jedt-12-2017-0130.
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Purpose This paper aims to compare glued laminated timber and steel beams with respect to structural design, manufacturing and assembly costs and the amount of greenhouse gas emissions. Design/methodology/approach This paper presents structural design requirements in conformance with EN 1993: Eurocode 5 and Eurocode 3. With the help of these standards, expressions are derived to evaluate the design criteria of the beams. Based on the results of life-cycle analysis, the economic properties and environmental impact of the two types of beam are investigated. In this paper, the effect of beam span on the design values, costs and carbon dioxide emissions is analysed when investigating aspects of the structural design, economy and environmental impact. Different cross-sections are chosen for this purpose. Findings The study shows that the glued laminated (abbreviated as “glulam”) beams have a smaller tendency to lateral torsional buckling than the steel beams, and that they can be cheaper. From an environmental point of view, glulam beams are the more environmentally friendly option of the two beam materials. Furthermore, glulam beams may have a direct positive effect on the environment, considering the carbon storage capacity of the wood. The disadvantage of glued wood is that larger dimensions are sometimes required. Research limitations/implications Wind load and the effect of second-order effects have not been considered when analysing the static design. Only straight beams have been studied. Furthermore, the dynamic design of the beams has not been investigated, and the bearing pressure capacity of the supports has not been analyzed. We have investigated timber beams with a rectangular cross-section, and steel beams of rolled I-sections, known as “HEA profiles”. The cost analysis is based mainly on the manufacturing and assembly costs prevalent on the Swedish market. The only environmental impact investigated has been the emission of greenhouse gases. The design calculations are based on the European standards Eurocode 5 and Eurocode 3. Practical implications To achieve sustainability in construction engineering, it is important to study the environmental and economic consequences of the building elements. By combining these two effects with the technical design of buildings made of steel and/or timber, the concept of sustainable development can be achieved in the long run. Social implications The study concerns sustainability of building structures, which is an important of the sustainable development of the society. Originality/value The paper contains new information and will be useful to researchers and civil engineers.
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Fojtík, Roman, und Veronika Vašková. „Analysis of Biological Damage of the Timber Footbridge“. Key Engineering Materials 832 (Februar 2020): 125–36. http://dx.doi.org/10.4028/www.scientific.net/kem.832.125.
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Glued laminated timber – Glulam is commonly used for the constructing of wooden structures in the interior and exterior. Wood as an organic material and may be the subject to a biological processes that can be a risk, mainly for construction on the exterior. Analyzed footbridge is made of glued laminated timber and is build in the Czech Republic. Analysis shows a serious disturbance caused by biological influences only a few years after construction completion. This article described summary of analysis of timber footbridge damage and their causes.
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Klapálek, Pavel, und Lenka Melzerová. „Non-Destructive Testing of Glued Laminated Timber Beams with Use of Pilodyn 6J – Method of Spike“. Applied Mechanics and Materials 825 (Februar 2016): 23–26. http://dx.doi.org/10.4028/www.scientific.net/amm.825.23.
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This article is focused on GLULAM (glued laminated timber) beams and determination of their properties by using non-destructive method. This text is mainly focused just on part of more complex research of glued laminated timber beams. This text is focused on non-destructive method, which is the method of spike that uses device called Pilodyn 6J for measurement. Results of this method are in form of Young ́s modulus of elasticity. This article will describe how the method of spike works, with basic description, describes the tested material and compare the results of testing. In the conclusion we discuss the results, make conclusions and describe the way of our further research of glued laminated timber beams.
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Karacabeyli, Erol, Conroy Lum und Link Olson. „Strength and stiffness of glulam trusses with punched metal plated joints“. Canadian Journal of Civil Engineering 20, Nr. 4 (01.08.1993): 622–30. http://dx.doi.org/10.1139/l93-079.
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Several Canadian wood truss manufacturers expressed a need to develop technical information to initiate the fabrication and acceptance of wood trusses made with glued-laminated timber (glulam) members and connected by punched metal plates. In collaboration with industrial participants, Forintek Canada Corp. developed a program for testing and analysis of metal plated glulam trusses. Twelve 3/12 pitched chord trusses and three parallel chord trusses, all 13.7 m long, were designed by three different plate manufacturers. All truss fabrication took place at a single truss manufacturing plant. Trusses composed of 79 mm wide and 152-229 mm deep glulam members connected by 16-gauge punched metal plates were tested to failure. The ratio of ultimate to design load averaged 3.5, and varied between 2.7 and 4.4. Both wood and plate failure modes were observed. The results suggest that the sizes of glulam members used in this study are structurally suitable for use with 16-gauge metal connector plates. Key words: wood, trusses, glued-laminated timber, truss plates, strength, stiffness.
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Ramos, Fernando Murilo Gontijo, E. V. M. Carrasco und Francisco Carlos Rodrigues. „Cross Laminated Timber in the International Context and in Brazil: Most Relevant Aspects“. Key Engineering Materials 777 (August 2018): 543–47. http://dx.doi.org/10.4028/www.scientific.net/kem.777.543.
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Timber is still being rediscovered as building material of excellence in Brazil, and especially as one of the most environmentally friendly one. In the scenario of the production of sustainable buildings, the construction system that uses wood panels - widely used in Europe, USA and Canada - called Glued Laminated Timber (GLULAM) and Cross Laminated Timber (CLT), occupies a prominent place, especially by the possibility of using wood from planted forests. This work aims to provide an overview of what is being produced in Europe and in Brazil.
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Huč, Sabina, Staffan Svensson und Tomaž Hozjan. „Numerical analysis of moisture-induced strains and stresses in glued-laminated timber“. Holzforschung 74, Nr. 5 (26.05.2020): 445–57. http://dx.doi.org/10.1515/hf-2019-0025.
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AbstractChanges in relative humidity of the ambient air, RH (%), cause wetting and drying of wood material, which results in non-uniform moisture contents or moisture gradients, and consequently in moisture-induced stresses and strains in the glued-laminated timber (glulam) members. The aim of the present paper is to perform a hygro-mechanical analysis to predict the mechanical behavior of glulam specimens exposed to two RH regimes, causing wetting from 50% to 90% RH and drying from 90% to 50% RH, and compare the numerical to the experimental results. The aims are also to quantitatively analyze the influence of characteristic material parameters required in the multi-Fickian moisture transport model and the mechanical model on moisture-induced strains and stresses in glulam specimens and to determine the possibility of cracking of the material by analyzing the maximum tensile stresses perpendicular to the grain. Accurate numerical predictions of moisture contents and moisture-induced strains are obtained in the glulam specimens during wetting and drying as compared to the experimental results. The influence of a particular characteristic material parameter on moisture-induced strains and stresses is characterized as significant, but not crucial when a rough numerical estimation of the mechanical behavior of the glulam beam exposed to RH changes is required.
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Xu, Feng, Xiping Wang, Marko Teder und Yunfei Liu. „Acoustic impact testing and waveform analysis for damage detection in glued laminated timber“. Holzforschung 71, Nr. 10 (26.09.2017): 801–11. http://dx.doi.org/10.1515/hf-2016-0237.
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AbstractDelamination and decay are common structural defects in old glued laminated timber (glulam) buildings, which, if left undetected, could cause severe structural damage. This paper presents a new damage detection method for glulam inspection based on moment analysis and wavelet transform (WT) of impact acoustic signals. Acoustic signals were collected from a glulam arch section removed from service through impact testing at various locations. The presence and positions of internal defects were preliminarily determined by applying time centroid and frequency centroid of the first moment. Acoustic signals were then decomposed by wavelet packet transform (WPT) and the energy of the sub-bands was calculated as characteristics of the response signals. The sub-bands of 0–375 Hz and 375–750 Hz were identified as the most discriminative features that are associated with decay and delamination and therefore are indicative of the presence of delamination or decay defects. A defect diagnosis algorithm was tested for its ability to identify internal decay and delamination in glulam. The results show that depth of delamination in a glulam member can be determined with reasonable accuracy.
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Tsalkatidis, Themistoklis. „Numerical simulation and analytical study of glulam timber beams“. International Journal of Engineering & Technology 3, Nr. 2 (07.04.2014): 129. http://dx.doi.org/10.14419/ijet.v3i2.2140.
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Glulam beams or glued-laminated beams consist of sawn lumber laminations (timber) bonded with an adhesive material. This paper, through the mathematical description of the contact conditions that apply at the interfaces of glulam beams and the development of two three-dimensional finite element models by the use of the ANSYS software package, studies the flexural properties of unreinforced (UGB) and reinforced (RGB) glulam beams. The first computational model presents an unreinforced glulam beam that has been produced by three wood laminations of dimensions 6 by 3.6 by 176 cm. The latter one describes a reinforced glulam beam, which has been produced by gluing a 0.15 cm thick steel plate at the bottom edge of the previously described beam. The computational analysis indicates that the two glulam beams have significantly different bearing capacities under the same load and support conditions. The failure mode of the UGB is brittle whereas the one of the RGB is ductile. The numerical results of both models are in close agreement with experimental ones from the international literature. Keywords: Glulam Timber Beams, Numerical Simulation, Contact.
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Wdowiak-Postulak, Agnieszka, und Grzegorz Świt. „Behavior of Glulam Beams Strengthened in bending with BFRP Fabrics“. Civil and Environmental Engineering Reports 31, Nr. 2 (01.06.2021): 1–14. http://dx.doi.org/10.2478/ceer-2021-0016.
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Abstract The article presents results of an experimental studies on reinforcement of pine beams made from glued laminated timber with subsurface basalt fibers (BFRP). An experimental research program was presented, in which the bending strength of glued laminated timber of middle and lower quality class was increased after using BFRP basalt fabrics. Thanks to the use of BFRP reinforcement, an average load capacity increased by 47% and stiffness by 6% in comparison to non-reinforced elements. Based on the research, it was found that the use of BFRP basalt fabrics is an effective method for strengthening damaged wooden elements. Thus, it is an environmentally friendly method of improving the static work of structural elements by combining wood with other natural materials such as basalt fiber reinforced polymers.
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Vodiannikov, Mikhail A., und Galina G. Kashevarova. „Modeling of CFRP and Glulam Combined Action“. Materials Science Forum 928 (August 2018): 283–86. http://dx.doi.org/10.4028/www.scientific.net/msf.928.283.
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In this paper, the results of the structural analysis of glued laminated timber and its joints in corrosive environment are shown. This paper includes calculation results for dowel connections of wood structures using steel and carbon fibres cylindrical dowel pins in accordance with the applicable regulatory documents by means of finite element analysis in ANSYS software, as well as experimental findings.
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Faller, Ronald K., Michael A. Ritter, Barry T. Rosson, Michael D. Fowler und Sheila R. Duwadi. „Two Test Level 4 Bridge Railing and Transition Systems for Transverse Timber Deck Bridges“. Transportation Research Record: Journal of the Transportation Research Board 1696, Nr. 1 (Januar 2000): 334–51. http://dx.doi.org/10.3141/1696-35.
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The Midwest Roadside Safety Facility, in cooperation with the Forest Products Laboratory, which is part of the U.S. Department of Agriculture’s Forest Service, and FHWA, designed two bridge railing and approach guardrail transition systems for use on bridges with transverse glue-laminated timber decks. The bridge railing and transition systems were developed and crash tested for use on higher-service-level roadways and evaluated according to the Test Level 4 safety performance criteria presented in NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features. The first railing system was constructed with glulam timber components, whereas the second railing system was configured with steel hardware. Eight full-scale crash tests were performed, and the bridge railing and transition systems were acceptable according to current safety standards.
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Hu, Ying Cheng, und Fang Chao Cheng. „Reinforcement Design of Poplar Glulam“. Materials Science Forum 620-622 (April 2009): 137–40. http://dx.doi.org/10.4028/www.scientific.net/msf.620-622.137.
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Wood is one kind of renewable natural eco-material. Glued laminated timber (glulam) is an engineered wood product made from sawn lumber lamina glued together in horizontal layers. The application of glulam in the construction structure not only has great environmental value, but also reduces energy consumption and carbon emission of the construction. In this study, we evaluated the effects of different factors on the structural properties of glulam and designed several enhancement modes to reinforce the glulam with FRP (Fiber Reinforced Plastic). Then, we measured the mechanical properties of the glulam specimens in the different enhancement modes and selected the optimal reinforcement mode. The reinforcement method obviously increased the value of MOE and MOR of poplar glulam by 5%-15% and 5%-12% respectively. FRP length of 600mm was the optimal and most economic reinforcement length, and finger joint position of 300mm is the optimal position.
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Leggate, William, Robert L. McGavin, Andrew Outhwaite, Chandan Kumar, Adam Faircloth und Mark Knackstedt. „Influence of mechanical surface preparation methods on the bonding of southern pine and spotted gum: Tensile shear strength of lap joints“. BioResources 16, Nr. 1 (06.11.2020): 46–61. http://dx.doi.org/10.15376/biores.16.1.46-61.
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Southern pine and spotted gum are two of Australia’s most important locally produced commercial timbers. However, internationally, they are amongst the most problematic species to glue cost-effectively, especially for sawn-laminate-based structural engineered wood products, such as glulam and cross-laminated timber. This study investigated the efficacy of different pre-gluing wood surface machining preparations on the tensile shear strength of lap shear samples prepared from both species. Surface machining methods tested included planing, face milling, and sanding post-planing with 40 and 80 grit sandpaper. Wood face milling is not currently used commercially in Australia and has not previously been adequately tested on Australian commercial timbers to improve wood adhesion. Planing is currently the most common method used internationally for preparing wood surfaces for gluing. For both species, face milling with fast feed speed (45 m/min), slow cutter speed (57 m/s), and sanding treatments post-planing resulted in significantly higher tensile shear strength compared to planing for lap shear samples that had been subjected to an accelerated weathering process. Performance differences in tensile shear strength between surface machining methods are likely to be related to the effects of these machining methods on surface roughness, fibrillation, and sub-surface cell damage.
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Kinjo, Hitoshi, Yusuke Katakura, Takeo Hirashima, Shuitsu Yusa und Kiyoshi Saito. „Deflection behavior and load-bearing period of structural glued laminated timber beams in fire including cooling phase“. Journal of Structural Fire Engineering 9, Nr. 4 (10.12.2018): 287–99. http://dx.doi.org/10.1108/jsfe-01-2017-0009.
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Purpose This paper aims to discuss the fire performance of glulam timber beams based on their deflection behavior and load-bearing period, which were obtained from load-bearing fire tests under constant load conditions. Design/methodology/approach In this report, the fire performance, primarily deflection behavior and load-bearing period of glued laminated (glulam) timber beams will be discussed from the standpoint of load-bearing fire tests conducted during the cooling phase under constant load conditions. Then, based on the charring depth and the per section temperature transformation obtained from loading test results, the load-bearing capacity of the glulam timber beams will be discussed using the effective section method and the strength reduction factor, which will be calculated in accordance with the European standards for the design of timber structures (Eurocode 5). Findings In the cooling phase, the charring rate is decreases. However, as the temperature in the cross section rises, the deflection is increases. The failure mode was bending failure because of tensile failure of the lamina at the bottom of the beam. Moreover, a gap caused by shear failure in a growth ring in the beam cross-section in the vicinity of the centroid axis was observed. Shear failure was observed up until 1 to 3 h before end of heating. The calculated shear strength far exceeded the test results. Shear strength for elevated temperature of glued laminated timber is likely to decrease than the shear strength in Eurocode 5. Originality/value Unlike other elements, a characteristic problem of timber elements is that their load-bearing capacity decreases as they are consumed in a fire, and their bearing capacities may continue to degrade even after the fuel in the room has been exhausted. Therefore, the structural fire performance of timber elements should be clarified during not only the heating phase but also the subsequent cooling phase. However, there are few reports on the load-bearing capacity of timber elements that take the cooling phase after a fire into consideration.
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Karacabeyli, Erol, und Ricardo O. Foschi. „Glulam rivet connections under eccentric loading“. Canadian Journal of Civil Engineering 14, Nr. 5 (01.10.1987): 621–30. http://dx.doi.org/10.1139/l87-092.
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Results from theoretical and experimental studies on the strength of glulam rivet connections under eccentric loading are presented. Two failure modes are studied: (1) rivet yielding in bending with simultaneous bearing failure of the wood under the rivet's shank and (2) wood failure around the rivet cluster. The latter is studied using brittle fracture theory and a finite element analysis of the stress distribution in the wood around the rivets.Experimental results are shown to compare well with theoretical predictions for failure loads and type of failure, and design guidelines are proposed. Key words: fasteners, wood connectors, glued-laminated, nails, timber engineering.
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Neuenschwander, Jürg, Sergio J. Sanabria, Philipp Schuetz, Robert Widmann und Mareike Vogel. „Delamination detection in a 90-year-old glulam block with scanning dry point-contact ultrasound“. Holzforschung 67, Nr. 8 (01.12.2013): 949–57. http://dx.doi.org/10.1515/hf-2012-0202.
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Abstract Glued laminated timber (glulam) is known in timber constructions since more than 100 years. Glulam members can delaminate due to aging and excessive changes of temperature and humidity. This results in significantly reduced load bearing capability of the affected structural members. This contribution focuses on the ultrasonic point-contact inspection of gluing plane delamination as a nondestructive method. Ultrasonic measurements on a section of a 90-year-old roofing glulam member are presented. The results are compared with manual detection and evaluation of delamination with a feeler gauge, with X-ray computed tomography analyses, and with numerical simulations. Appropriate data evaluation of the mechanized ultrasonic results allows the determination of material separation that are deeper than 20 mm in the signature of the surface wave and large-scale delamination (>80% of the complete bonding width) in the back-wall echo. Numerical simulations based on the finite-difference time-domain method shed light into the details of the wave propagation and support the experimental findings.
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Sousa, Hélder S., Jorge M. Branco und Paulo B. Lourenço. „Glulam Mechanical Characterization“. Materials Science Forum 730-732 (November 2012): 994–99. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.994.
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The glued laminated timber (glulam) mechanical properties may be evaluated through the determination of the key mechanical properties of the lamellae that compose that element. Simple bending and tension parallel to the grain tests were performed in order to assess the strength class of three glulam elements. Regarding the bending tests, 8 samples were taken from a glulam beam and assessed. Values for the resistant bending tension and both local and global modulus of elasticity were obtained. For the tension parallel to the grain tests, a total of 120 samples were assessed. The samples were divided regarding the structural element from where they were extracted as well to the type of failure mode found in the tests. The values of the lamellae properties were then used for determination of the properties of the glulam material. The data gathered from the tests was assessed statistically and concluded that the mechanical properties of the glulam elements did not fulfill the required parameters of the normative requirements.
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Lepper, M. M., und F. J. Keenan. „Development of poplar glued–laminated timber. I: Tensile strength and stiffness of poplar laminating stock“. Canadian Journal of Civil Engineering 13, Nr. 4 (01.08.1986): 445–59. http://dx.doi.org/10.1139/l86-069.
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The tensile strength and stiffness of 263 full-size pieces of 38 × 80 mm in-grade poplar lumber from two mills in Ontario were determined. Prior to testing, complete maps of all grade-related defects in each piece were made; these defects included general slope of grain, centre knots, and edge knots. Specific gravity and moisture content were also recorded for each piece. After testing, the defects that triggered each piece's failure were noted. This information led, through regression analyses and the assumption of a Weibull distribution, to models for tensile strength and stiffness. The models were developed for the pieces from one mill and were tested against the results obtained from pieces from the other mill; agreement was very good. The knot frequency and slope frequency data were used in a modified form of the Foschi and Barrett glulam beam simulation model to predict the fifth fractile value of a population of poplar glulam beams. Taking the volume effect into account, the predicted beam strengths and stiffnesses are close to those of glulam beams of stress grade 20f–E.
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Abade Bertolino, Carlos Augusto, Nilson Tadeu Mascia, Cilmar Donizeti Basaglia und Bruno Fazendeiro Donadon. „Analysis of Fiber Reinforced Laminated Timber Beams“. Key Engineering Materials 668 (Oktober 2015): 100–109. http://dx.doi.org/10.4028/www.scientific.net/kem.668.100.
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The necessity to restore the design specifications of a determined structure, combined with cost, weight and environmental impact reduction makes the use of high performance composite systems, involving, either synthetic or natural materials, interesting. By applying a layer of fiber reinforcement bonded with the glued laminated timber beam (Glulam) with an appropriate adhesive, a high performance composite system is obtained, resulting on a significant increase of strength and bending stiffness of the structural element that each isolated material did not have before. This paper carried out an analysis of the feasibility of use synthetic and natural fibers as alternative to structural reinforcement to laminated timber beams, made of the reforestation wood species Pinus caribea and Eucalyptus grandis that represent respectively two resistance classes of monocotyledon and dicotyledonous, exposing, through an analytical model. The numerical results obtained from the analysis of the Glulam beams reinforced with glass, carbon, Vectran® and natural fibers such as sisal fibers, are compared among each other considering cost, weight and gain of resistance and stiffness. It is observed that for small lengths (and therefore, small cross sections), the use of Vectran® fiber is not the best option, since an equivalent resistance gain can be obtained by applying a thicker layer of glass fiber, once it possesses a lower cost and a non-significant impact on the final structure's weight. For all the other considered cases, the choice of the Vectran® fiber is very interesting, since on these situations a thicker layer of glass fiber does not provide much cost reduction and is not enough to achieve the desired strength without increasing the structure's weight significantly. Regarding the sisal fiber, it is a material that is easy to find and with a low cost in Brazil, its utilization is interesting when working with low resistance wood species. Although the gain of resistance provided by this fiber as a reinforcement material is fairly low, the desired result can be obtained by increasing the thickness of the reinforcement layer, which still keeps the cost and weight of the reinforced element much smaller than those resulting from the implementation of a thinner layer of glass fiber.
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Schlotzhauer, Kovryga, Emmerich, Bollmus, Van de Kuilen und Militz. „Analysis of Economic Feasibility of Ash and Maple Lamella Production for Glued Laminated Timber“. Forests 10, Nr. 7 (26.06.2019): 529. http://dx.doi.org/10.3390/f10070529.
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Background and Objectives: In the near future, in Europe a raised availability of hardwoods is expected. One possible sales market is the building sector, where medium dense European hardwoods could be used as load bearing elements. For the hardwood species beech, oak, and sweet chestnut technical building approvals already allow the production of hardwood glulam. For the species maple and ash this is not possible yet. This paper aims to evaluate the economic feasibility of glulam production from low dimension ash and maple timber from thinnings. Therefore, round wood qualities and the resulting lumber qualities are assessed and final as well as intermediate yields are calculated. Materials and Methods: 81 maple logs and 79 ash logs cut from trees from thinning operations in mixed (beech) forest stands were visually graded, cant sawn, and turned into strength-graded glulam lamellas. The volume yield of each production step was calculated. Results: The highest volume yield losses occur during milling of round wood (around 50%) and “presorting and planning” the dried lumber (56–60%). Strength grading is another key process in the production process. When grading according to DIN 4074-5 (2008), another 40–50% volume loss is reported, while combined visual and machine grading only produces 7–15% rejects. Conclusions: Yield raise potentials were identified especially in the production steps milling, presorting and planning and strength grading.
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Zhao, Xuan, Binsheng Zhang, Tony Kilpatrick, Iain Sanderson und Dewen Liu. „Numerical Analysis on Global Serviceability Behaviours of Tall Glulam Frame Buildings to the Eurocodes and UK National Annexes“. Journal of Civil Engineering and Construction 10, Nr. 3 (15.08.2021): 109–22. http://dx.doi.org/10.32732/jcec.2021.10.3.109.
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Glued-laminated timber (Glulam) is an innovative engineered timber product and has been widely used for constructing spatial grand timber structures and tall timber buildings due to its exceptional natural attraction, easy processing, decent fire resistance and outstanding structural performance. However, global serviceability performances of tall timber buildings constructed from Glulam products for beams, columns and bracings and CLT products for lift core and floors under wind load are not well known yet though they are crucial in structural design and global analysis. In this study, finite element software SAP2000 is used to numerically simulate the global static and dynamic serviceability behaviours of a 105 m high 30-storey tall Glulam building with CLT lift core and floors assumed in Glasgow, Scotland, UK. The maximum horizontal storey displacement due to wind is 58.5% of the design limit and the maximum global horizontal displacement is 49.7% of the limit set to the Eurocodes. The first three lowest vibrational frequencies, modes and shapes of the building are obtained, with the fundamental frequency being 33.3% smaller than the code recommended value due to its low mass and stiffness. The peak acceleration of the building due to wind is determined to the Eurocodes and ISO 10137. The results show that the global serviceability behaviours of the building satisfy the requirements of the Eurocodes and other design standards. Parametric studies on the peak accelerations of the tall Glulam building are also conducted by varying timber material properties and building masses. Increasing the timber grade for CLT members, the generalised building mass and the generalised building stiffness can all be adopted to lower the peak accelerations at the top level of the building so as to reduce the human perceptions to the wind induced vibrations with respect to the peak acceleration.
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Teles, Ricardo Faustino, Cláudio Henrique Soares Del Menezzi, Mário Rabelo de Souza und Frederico de Souza. „Effect of nondestructive testing of laminations on the bending properties of glulam beams made from louro-vermelho (Sextonia rubra)“. CERNE 16, Nr. 1 (März 2010): 77–85. http://dx.doi.org/10.1590/s0104-77602010000100009.
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This work aims to assess the bending properties of glued laminated timber beams (glulam) manufactured with species louro-vermelho (Sextonia rubra). Laminations were nondestructively tested using the transverse vibration method (E Mlam). Then 10 glulam beams were manufactured and tested in static bending according to ASTM D 198 standard, having modulus of elasticity (E M), modulus of rupture (fM), and bending moment (M) determined. The finished beams were also tested by the transverse vibration method (E Mvt). It was noted that the E Mvt value was only 2% lower than the E M value. Using laminations with a high modulus of elasticity did allow effective gain in stiffness. Therefore, results indicate that the transverse vibration method is a valid, reliable technique both for testing glulam laminations and for assessing stiffness in finished beams. Bending properties in glulam beams were influenced by the stiffness of constituent laminations.
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Wipf, Terry J., Michael A. Ritter und Douglas L. Wood. „Evaluation and Field Load Testing of Timber Railroad Bridge“. Transportation Research Record: Journal of the Transportation Research Board 1696, Nr. 1 (Januar 2000): 323–33. http://dx.doi.org/10.3141/1696-34.
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Several spans of a 60-year-old open-deck timber railroad bridge on the Southern Pacific Railroad Line (now the Union Pacific) in Southwest Texas were field tested. The tests were conducted with the sponsorship and cooperation of the Association of American Railroads to determine the vertical live load distribution characteristics of the superstructure. The bridge was originally constructed with Douglas-fir larch solid sawn stringers but was rehabilitated on several occasions to allow comparisons to be made with respect to different rehabilitation options, including the use of a helper stringer and the use of glued laminated timber (glulam) stringers. The test spans measured approximately 4.1 m (13.5 ft) center-to-center of supports and included two closely “packed” chords, each consisting of four timber stringers (one test span included an additional helper stringer added to one chord). One chord was made up of glulam timber and the other was made up of solid sawn timber. The bridge superstructure was generally in satisfactory condition, with some stringer horizontal splitting noted over the bents. The bents were in reasonably good condition, but chord bearing was uneven on bent caps. Static and dynamic deflection load test data were obtained using a special test train. The test results indicate that the glulam chord performed better than the older sawn stringer chord, even when a helper stringer was added. Individual stringers within a chord did not always share the load equally.
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Wang, Zhi Feng, Xian Yan Zhou und Da Hai Zhang. „Structural Condition Evaluation of an In-Service Glued-Laminated Timber Bridge Based on the Dynamic and Static Testing“. Applied Mechanics and Materials 847 (Juli 2016): 31–37. http://dx.doi.org/10.4028/www.scientific.net/amm.847.31.
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The structural use of wood has increased steadily in recent times, including a renewed interest in the use of timber as a bridge material. As the only environment-friendly and resource-saving building material, wood has been gradually uesd for short and medium span bridges in China. In 2014, The domestic largest single-span glued-laminated timber (glulam) deck arch bridge crossing a freeway was completed and put into operation in Zhangjiajie City, central China' Hunan province. In order to know the bearing capacity of superstructures and assess its working conditions, in-site static and dynamic testings has been carried out. Many measures including finite element simulation, field test and comparision between test results and calculated results have been employed to study responses of the bridge under static loads and dynamic loads as well. The researches indicate this glulam footbridge has performed well in service and appear to be cost effective when compared with the cost of installing traditional concrete and steel bridges.
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Abbott, A. R., und L. R. J. Whale. „An overview of the use of glued laminated timber (glulam) in the UK“. Construction and Building Materials 1, Nr. 2 (Juni 1987): 104–10. http://dx.doi.org/10.1016/0950-0618(87)90007-9.
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GLIŠOVIĆ, Ivan, Marko PAVLOVIĆ, Boško STEVANOVIĆ und Marija TODOROVIĆ. „NUMERICAL ANALYSIS OF GLULAM BEAMS REINFORCED WITH CFRP PLATES“. Journal of Civil Engineering and Management 23, Nr. 7 (13.07.2017): 868–79. http://dx.doi.org/10.3846/13923730.2017.1341953.
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This paper presents an analysis of bending behaviour of glued laminated timber (glulam) beams reinforced with carbon fibre reinforced polymer (CFRP) plates, based on finite element numerical modelling. Nonlinear 3-dimensional model was developed and validated by experimental tests carried out on unreinforced beams and beams reinforced with two different reinforcement arrangements. Suitable constitutive relationships for each material were utilised in the model, as well as anisotropic plasticity theory for timber in compression. Adhesive bond between CFRP plate and timber was modelled as a perfect connection. Beam failure in the model was defined by maximum stress criterion. The predicted behaviour of beams has shown good agreement with the experimental results in relation to load-deflection relationship, ultimate load, elastic stiffness and strain profile distribution. The non-linear behaviour of reinforced beams before failure was also achieved in the numerical analysis, confirming the finite element model to be accurate past the linear-elastic range. Experimentally tested reinforced beams usually failed in tensile zone after compressive plasticization of top lamination, which was also simulated in the numerical model. The results proved that the load carrying capacity, stiffness and ductility of glulam beams were successfully increased by addition of CFRP plate at tension side of the section.
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Glišović, Ivan, Boško Stevanović und Miloš Petrović. „BENDING BEHAVIOUR OF GLULAM BEAMS REINFORCED WITH CARBON FRP PLATES“. Journal of Civil Engineering and Management 21, Nr. 7 (10.07.2015): 923–32. http://dx.doi.org/10.3846/13923730.2014.897969.
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The idea of reinforcing glued laminated timber (glulam) beams came in response to the need to improve the mechanical properties, as well as to ensure higher reliability of this type of structural elements. This paper describes an experimental program which examines the reinforcement in flexure of glulam beams with carbon fibre reinforced plastic (CFRP) plates. Fifteen beams reinforced with CFRP at the tension side and five unreinforced control beams were instrumented and tested to failure in a four-point bending configuration. The mechanical properties of reinforced beams are compared to those of unreinforced beams with regard to the load-deflection behaviour, failure mode, ultimate load capacity, stiffness and strain distribution. The experimental results demonstrated the beneficial effect of the proposed reinforcing solution in terms of strength, stiffness and ductility.
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Nareswarananindya, Nareswarananindya. „EKSPLORASI MATERIAL GLULAM PADA PERANCANGAN SHELTER MENGGUNAKAN SALURAN KREATIVITAS FOCUS ON MATERIAL“. BORDER 1, Nr. 2 (30.11.2019): 83–96. http://dx.doi.org/10.33005/border.v1i2.27.
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Setiap material memiliki karakteristik yang dapat dieksplorasi dan digunakan sebagai saluran kreativitas dalam merancang bangunan. Proses eksplorasi material tersebut harus dapat mendukung efisiensi penggunaan sumber daya dalam keseluruhan daur hidup (life cycle) bangunan, mulai dari pemilihan material, desain, konstruksi, pemeliharaan, hingga pembongkaran. Glued Laminated Timber (Glulam) merupakan salah satu material alternatif dari bahan dasar kayu yang dapat diperbaharui dan memiliki low embodied energy. Dengan menggunakan saluran kreativitas focus on material, karakteristik dari glulam digunakan sebagai pendekatan merancang bangunan. Tipe bangunan yang digunakan sebagai obyek eksplorasi adalah bangunan sederhana non-ruang, yaitu shelter (naungan). Proses rancang menggunakan Cyclical Design Process yang terdiri dari tahap analisis, sintesis, dan evaluasi yang dilakukan berulang-ulang hingga mendapat rancangan paling yang optimal. Tahap analisis data dari glulam, shelter, dan focus on material dilakukan untuk menghasilkan kriteria desain yang akan digunakan untuk menghasilkan beberapa alternatif rancangan pada tahap sintesis. Beberapa alternatif rancangan tersebut kemudian di evaluasi pada tahap evaluasi untuk mendapatkan rancangan yang paling sesuai. Hasil yang diperoleh adalah rancangan skematik bangunan shelter dengan bentuk single curve dan double curve yang tersusun dari konfigurasi monomaterial elemen-elemen glulam berukuran 60x60 cm menggunakan sambungan takik.
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Nakashima, Shoichi, Akihisa Kitamori und Kohei Komatsu. „Load Carrying Capacity of Drift Pin Joint of Cross Laminated Timber (CLT) with Steel Insert Plate“. Wood Research Journal 4, Nr. 1 (19.04.2017): 87–93. http://dx.doi.org/10.51850/wrj.2012.3.2.87-93.
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Cross Laminated Timber (CLT) is a structural plate element which is approved in Europe and is intended to be approved in Japan. It consists of small dimension laminae, in which laminae parallel and perpendicular to longitudinal direction are interlaminated. We performed tensile tests for the drift pin joint with steel insert plate. Specimen consisted of CLT was made from Japanese cedar laminae (thickness of laminae t = 30mm, five laminae were layered), with steel drift pin plate. Odd-numbered layers were parallel to the longitudinal axis, and even-numbered layers were perpendicular to the longitudinal axis. The experimental parameters were edge distances (3d, 4d and 7d), end distances (3d, 4d and 7d) and diameters of pin (12 and 16 mm) and the replication were three respectively. Initial stiffness was lower than the results of glulam drift pin joint loaded in parallel to the grain, however second stiffness after the yield of drift pin was higher because the lateral compression occurred at even-numbered layers. Additionally, ductility was higher because split failures around the pin were prevented by the glued effect of interlaminated layers. As the characteristic value of test results, initial stiffness K, yield load Py, maximum load Pmax, indicated the effect of the difference of the diameter of the pin, while deformation capacity indicated the effect of edge distance.
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Rocco Lahr, Francisco Antonio, André Luis Christoforo, Cristiane Inácio de Campos, Elen Aparecida Martines Morales, Juliana Cortez Barbosa und Túlio Hallak Panzera. „Evaluation of the Moisture Content in Stiffness Properties of Structural Glulam Beams“. Advanced Materials Research 1088 (Februar 2015): 676–79. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.676.
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This research aimed to evaluate the influence of storage time (0, 96 hours) ofPinus elliottiipieces and the tests to obtaining modulus of elasticity (static bending and transversal vibration) in glued laminated timber beams, produced with resorcinol based adhesive and 0.8 MPa compaction pressure. After pieces were properly prepared, part of them was used in immediate three manufacturing glulam beams, tested after adhesive cure, and part stored for 96 hours under a roof with a temperature of 25°C and relative humidity of 60% for subsequent manufacturing and testing three other glulam beams. Results of analysis of variance (ANOVA) revealed that the storage period was significant influence in modulus of elasticity obtained in static bending test (8% reduction from 0 to 96 hours). This not occurred with modulus of elasticity obtained by transversal vibration test (no significant influence). ANOVA results showed equivalence of means in both test procedures.
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Holzer, S. M., C. H. Wu und J. Tissaoui. „Finite Element Stability Analysis of a Glulam Dome“. International Journal of Space Structures 7, Nr. 4 (Dezember 1992): 353–61. http://dx.doi.org/10.1177/026635119200700411.
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The paper centres on stability investigations of a glued-laminated timber (glulam) dome under several snow load conditions. The dome consists of a triangulated network of curved glulam beams, a decking supported by curved purlins, and a steel tension ring. The dome is represented by two different models. The first model is a rigid-jointed space frame composed of curved beam elements. The second model consists of straight beam elements, with rigid or flexible joints, and a bracing to simulate the lateral support of the beams provided by the decking. Two finite element methods are presented and used in the analyses: A nonlinear method that computes the buckling load and a combined nonlinear/linear eigenvalue method that provides estimates of the buckling load. The results presented include buckling pressures, buckling modes, effects of joint stiffness and bracing on the stability of the dome, and the status of the material prior to buckling.
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Albrektas, Darius, und Ernestas Ivanauskas. „An Assessment of Environmental Impact on Glued Wood Building Elements“. Drvna industrija 72, Nr. 1 (11.02.2021): 39–47. http://dx.doi.org/10.5552/drvind.2021.2001.
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The research investigated the impact of environmental factors (temperature and humidity) on pine glulam, oak glulam, and laminated veneer lumber (LVL) elements, all of which can be used in building structures. Elements underwent freezing, heating, drying, and wetting processes in different modes, thereby simulating different environmental conditions that could be encountered during the service period of the materials. Their mechanical properties (modulus of elasticity - MOE and coefficient of damping) were recorded at each stage. It was determined that, in the case of dry construction elements (where a moisture content was between 7.0 and 14.0 %), the MOE increases by a few percentage points with decreasing temperature and humidity levels, and decreases with increasing temperature and humidity levels. The coefficient of damping varied by 20 % - in most cases, when the modulus of elasticity increased, this decreased, and vice versa. Under extreme environmental changes (with the elements being soaked, frozen at -25 °C, and dried at 40 °C), the MOE of the glued timber decreased by 16 % when this parameter of LVL decreased by about 10 %. Alterations in viscous properties produced similar results (the coefficient of damping increased by 50 % for the glued timber and by 66 % for the LVL). This is explained by the partial destruction of the element structure, the occurrence of cracks, and the decreased anisotropy of the LVL structure.
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Weckendorf, Jan, Henry Meleki Kiwelu und Ian Smith. „Critical reaction forces of glulam members with tension-side notches at end supports“. Canadian Journal of Civil Engineering 42, Nr. 10 (Oktober 2015): 779–86. http://dx.doi.org/10.1139/cjce-2014-0466.
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Tests were carried out on softwood structural glued-laminated-timber (glulam) members to calibrate a linear elastic fracture mechanics design method for bending members having tension-side end notches. Fifty-eight specimens with depths up to 646 mm represented 11 combinations of member size, notch depth, member geometry, loading arrangement, and glulam type. Specimens were loaded until they sustained significant damage at or near notch locations, but none of them failed as bending members. Notch damage started with creation of short stable cracks parallel to the laminations and ended with episodically crack growth. Typically, crack initiation is at about half the load level associated with episodic crack growth. Contrary to current design practice loads positioned close to notched end supports were found to influence strengths of members significantly, and their effects should be taken into account. The findings have been implemented in the 2014 edition of CAN/CSA Standard 086 “Engineering Design in Wood”.
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Smith, Ian, Henry Meleki Kiwelu und Jan Weckendorf. „Explanation of tension-side notch design provisions for glulam in CSA Standard 086-14“. Canadian Journal of Civil Engineering 42, Nr. 10 (Oktober 2015): 787–96. http://dx.doi.org/10.1139/cjce-2015-0088.
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Traditionally unreinforced tension-side notches at supports of glued-laminated-timber (glulam) bending members have been designed in Canada assuming shear capacity is reduced in proportion to the square of the residual depth ratio. The origin of that practice lies in World War II era studies in the USA on solid wood members. More recent research in Canada, US, and Europe has focussed on application of linear elastic fracture mechanics (LEFM) methods to such problems, reflecting that such approaches can account for effects of variables other than notch depth ratio. Canadian wood design code CSA Standard 086 “Engineering Design in Wood” first capitalized on availability of LEFM approaches in 1994 by adopting such a method for design of sawn lumber members with tension-side notches at supports. The same was not done then for glulam members because of paucity of supporting test data. That gap has now been filled and the 2014 edition of CSA Standard 086 employs consistent LEFM based design approaches for both sawn lumber and glulam members with tension-side notches. New provisions for glulam recognize influences that notch length and shape, and how laminations in members are fabricated have on member capacities. Discussion here addresses the logic that underpins the new glulam provisions and how application of those provisions impacts design solutions. Overall impact of the new design provisions is to discourage use of relatively large tension-side notches at supports of larger glulam bending members, while not discouraging use of notches in smaller glulam members.
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Haiman, Miljenko, und Nenad Turčić. „Timber-Lightweight Aggregate Composite Floor Structure“. Materials Science Forum 730-732 (November 2012): 486–91. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.486.
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Nowadays, composite structures based on wood are frequently used. In civil engineering, mostly timber-concrete composite structures are used, particularly in reconstruction of old timber girder floor structures or manufacture of new ones at the reconstruction of old buildings in areas exposed to frequent earthquakes. In new buildings it is mainly glued laminated timber or lumber, while in reconstruction square timber is used. A timber beam is coupled with a concrete slab made either of conventional or a lightweight concrete. Best results are achieved by coupling timber with lightweight aggregate concrete that has all the properties similar to the timber except for its strength that is much higher and comparable to that of conventional concrete. This paper analyzes a composite timber-lightweight aggregate concrete structure. The basic girder is a T-cross section, with the web made of glulam, and flange made of lightweight concrete with expanded clay aggregate (Liapor). The two materials are coupled by means of mechanical fasteners, allowing joint action of the composite section. Quality of coupling has been determined by experimental tests carried out at the Laboratory of the Technical Mechanics Institute, Faculty of Civil Engineering in Zagreb. Finite element method was used for modelling of composite structures using ABAQUS software. The aim of this study was to determine the advantages of using timber-lightweight aggregate concrete composite structure, compared to solutions in which timber-conventional concrete composite structure or reinforced concrete slab are used.