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This paper presents test evaluation results for red maple structural glued-laminated (glulam) beams manufactured from two different lumber resources. Two types of red maple glulam beam combinations were evaluated: 1) a glulam combination designed with E-rated lumber in 25 percent of the outer laminations (top and bottom) and visually graded lumber...
Citations
... According to Moody and Hernandez [4], species and mixed-species combination commonly used for glued-laminated timber in the United States include southern pine (Pinus spp.), Douglas fir (Pseudotsugamenziesii), larch (Larixoccidentalis), hemlock (Tsugaheterophylla), and spruce (Picea spp.). Red maple (Acer spp.) species was also used by Janowiak et al. [5] to study the performance of glulam beam made from two distinct timber resources, namely sawn logs and lower-grade, smaller-dimension timber. Komariah et al. [6] developed glulam made from sengon, manii, and mangium, with either the same wood species being used for all layers or mangium being used for the face and back layers, with a core layer of manii or sengon. ...
The aim of this paper was to investigate the physical (thermal transmittance and dimensional stability) and mechanical properties of two types of three layer laminated wood made from fir and meranti; fir in surface layers and meranti in core (FMF) and vice versa (MFM) and to examine its potential application for wood-frame windows. An additional objective was to compare the properties of the laminated wood with those of solid wood, namely meranti and fir. Both types of laminated wood had by far substantial lower bending properties than solid wood. MFM laminated wood performed better than the FMF as far as the physical and mechanical properties are concerned. Water absorption and thickness swelling of MFM laminated wood were substantially lower than those of the FMF type, and all the differences were statistically significant. Longitudinal width swelling, and bending properties of MFM laminated wood were higher than those of FMF but these differences were not statistically significant. The thermal transmittance (rate of the heat transferred) of the FMF window is 13.3% better (less) compared to the MFM window. The main reason for this is believed to be the lower overall density of the FMF window, which also makes it more competitive as a result of the reduced manufacturing cost since fir is less expensive compared tomeranti. It was concluded that wood-frame windows can be successfully made from these types of laminated wood, employing therefore easily renewable materials, with low environmental impact, recyclable and manageable in the medium term.
... Mixed species combination commonly used in the United States include Douglas Fir (Pseudotsuga menziesii)-Larch (Larix occidetalis), Hemlock (Tsuga heterophylla)-Douglas Fir and Spruce (Picea spp.)-Pine (Pinus spp.)-Fir-Red Maple (Acer spp.) [6]. Other mixed species combination studied by other reserachers includes Poplar (Populus X euramaricana) -Eucalyptus (Eucalyptus grandis) [4] as well as Sugi (Cryptomeria japonica) -Hinoki (Chamaecyparis obtuse) and Douglas Fir [7]. ...
This study investigates the bending and bonding performances of glued laminated timber beams manufactured using a combination of Malaysian lower and higher- grade timber species. Two types of beams were prepared which were mono-species and mixed-species glulam. Mono-species glulam with uniform layup were fabricated using Merpauh, Jelutong and Sesendok. Mixed-species glulam with balanced layup were fabricated whereby Merpauh was positioned equally at the outer layers and either Jelutong or Sesendok were positioned at the inner layers. Three replicates of ten-layered glulam beams measuring 100 mm in width, 300 mm in depth and 6200 mm in length were manufactured according to MS758 for each mono and mixed-species glulam. Bending, delamination and block shear tests were done on all the glulam beams. The results show that glulam manufactured from the combination of Sesendok and Merpauh obtained the highest bending properties and structural efficiency. In addition, the bonding performance at the interface between Sesendok-Merpauh lamellas proved to be excellent.
... The HW glulam elements from ash and maple are also promising ( . In North America, maple glulam has a still unused high application potential (Manbeck et al. 1993;Janowiak et al. 1997). The key issues of HW glulam are the bonding and strength grading of the lamellas including the selection of an appropriate adhesive system and the durability of the composites (Aicher and Reinhardt 2007;Konnerth et al. 2016). ...
... However, the accuracy is species specific and can be poor even for the multivariate models, which combine visual and machine parameters (R 2 of 0.33 for chestnut) (Vega et al. 2012). In the case of oak, beech and red maple, the machine measurements were combined with manual knottiness measurement for high quality lamella (Janowiak et al. 1997;Frese and Blaß 2007;Ehrhart et al. 2016b), which resulted in threshold values without compensating the values in a single regression model. The throughput rate of this approach is low. ...
... There are indicators that pith boards do not affect the properties of glulam, as shown by Janowiak et al. (1997), who found that the quality of the inner and outer log materials are very similar. On the other hand, pith boards tend to have a higher number of splits (Glos and Lederer 2000) and the glulam TS perpendicular to the grain (TS ⊥ ) is also deteriorated in presence of pith. ...
Medium dense hardwoods (HWs) show higher tensile strength (TS) values than softwoods (SWs). These advantages cannot be utilised effectively because HW grading is not well developed. The aim of the present paper was to analyse the utilisation potential of European ash ( Fraxinus spp.) and maple ( Acer spp.) grown in Central Europe, which were graded by different methods. The visual grading characteristics of 869 HW boards were determined and the dynamic modulus of elasticity (MOE dyn ) and X-ray attenuation (XRA) were measured by an industrial scanner. The specimens were subsequently tested in tension according to EN 408:2010 and according to German visual grading rules show strength values of 28 MPa and 30 MPa, respectively. Machine strength grading and for a combination of manually assessed boards and MOE dyn give rise to higher strength data. MOE dyn , in particular, results in lamella data with 62 MPa for ash and 42 MPa for maple. There is good agreement with recently presented HW tensile profiles. Machine grading with a multisensor system allows better strength prediction compared to the MOE dyn or visual strength grading. Best performance is achieved by a combined grading approach.
... According to Moody and Hernandez [3], species and mixed- species combination commonly used for glued-laminated timber in the United States include southern pine (Pinus spp.), douglas fir (Pseudotsuga menziesii)-larch (Larix occidentalis), hemlock (Tsuga heterophylla)-douglas fir and spruce (Picea spp.)-pine-fir. Red maple (Acer spp.) species was also used by Janowiak et al. [4] to study the performance of glulam beam made from two distinct timber resources namely sawn logs and lower-grade, smaller dimension timber. In Europe, on the other hand, Norway spruce is the most commonly used species for glulam [5]. ...
... According to Moody and Hernandez [3], species and mixedspecies combination commonly used for glued-laminated timber in the United States include southern pine (Pinus spp.), douglas fir (Pseudotsuga menziesii)-larch (Larix occidentalis), hemlock (Tsuga heterophylla)-douglas fir and spruce (Picea spp.)-pine-fir. Red maple (Acer spp.) species was also used by Janowiak et al. [4] to study the performance of glulam beam made from two distinct timber resources namely sawn logs and lower-grade, smaller dimension timber. In Europe, on the other hand, Norway spruce is the most commonly used species for glulam [5]. ...
Fastener performance evaluation was conducted on three types of connector systems used to fasten 5-1/8-inch red maple glued-laminated (glulam) materials to 1-inch-thick steel plates: twin 3/4-inch-diameter hook bolts, bolted offset shoes, and lagged offset shoes. Collectively, experimental evaluation included 255 (225 uncycled and 30 cycled) test assemblies that connected red maple glulam to steel plates to better characterize resistance property values of the different connector systems. The hook bolt connector system consistently yielded higher P 5% and k 1 performance values, followed by the bolted offset shoe systems, then the lagged offset shoe assemblies (tested under single static loading). Differences in load-resistance performance for the bolted and lagged offset shoe systems were less pronounced compared to average hook bolt values. In most cases, average offset yield load (P 5%) and stiffness values (k 1) were observed to decrease after cyclic displacement exposure when compared to test assemblies exposed only to single static loading. All three types of connector systems appear favorable for glulam timber deck-to-steel I-beam fasteners. However, the lagged shoe type connection may be the more advantageous system with far less glulam processing requirements and greater overall simplicity for potential bridge glulam deck-to-steel girder applications. Design values have been estimated and are presented for the different bridge deck-to-girder joint mechanisms.
The feasibility of producing structural glulam (Glued laminated timber) with 30-year-old Japanese cedar (Cryptomeriajaponica) plantation wood was investigated in the study. The yield of sawn laminae from logs with on average diameter of 200 mm was 47.7%, and the yield for producing medium-sized glulam pieces of 100 × 304 × 6150 mm from rough sawn laminae was 62.9%. Higher quantities of laminae and higher yields were obtained as the diameter of logs increased from 150 to 300 mm. A major grade of no. 3 or lower was obtained as Japanese cedar laminae were visually graded based on wood defects in terms of appearance, while better discrimination among L60-L90 grades was obtained based on the static modulus of elasticity determination. The coefficient of determination, R2, was 0.82 between the dynamic modulus of elasticity from the tap tone method and static modulus of elasticity for laminae, and R2 of 0.71 was obtained between the sound velocity and static modulus of the elasticity indicating an advantage of rapid evaluation approach. The bending strength of finger-jointed Japanese cedar laminae was 363 kgf cm -2, which was 63.7% of that without the finger joints. Balanced structural glulam pieces of E85-F255 and E65-F225 grades were obtained using combinations of laminae with higher elasticities.
World demand for engineered lumber products is driven by a shift to performance-based building codes; the changing nature of the softwood fiber supply; worldwide demand for affordable housing; and advances in resin technology and wood conversion systems. From structural composite lumber to prefabricated wood I-joists and glulam, these products extend the forest resource by allowing higher product recoveries and using conversion technology that facilitates broader use of underutilized species and sizes. They also enable higher stumpage prices as markets are created for a wider range of species, grades, and sizes of timber. And sustainable forestry objectives are enhanced as markets for small-diameter, low-grade fiber are developed throughout the world.
