compressive strength of timber

Keywords: Cross-laminated timber; Compressive strength; Perpendicular to the grain; In-plane; Out-of-plane; Larch, Contact information: College of Forest & Environmental Sciences, Kangwon National University, Chun-Cheon 200-701, Republic of Korea; *Corresponding author: hongsi@kangwon.ac.kr. For example, the compression and bending strength of wood increase by about two-fold as wood dries from fresh to 12-15%. It is easy to work with and can be produced in a wide range of shapes and sizes. (2018). In addition, a performance evaluation of the compressive strength perpendicular to the grain of CLT must be performed because timber- and wood-based materials generally have a lower measure of compressive strength perpendicular to the grain. Glulam columns made of European beech timber: compressive strength and stiffness parallel to the grain, buckling resistance and adaptation of the effective-length method according to Eurocode 5 Thomas Ehrhart . You can target the Engineering ToolBox by using AdWords Managed Placements. 1. 3.3.1 The compressive properties obtained by this method are a reliable approximation of the strength of a full-size panel, and are intended for use in design. As the CLT floor is located between the upper and lower walls, however, it can be considerably deformed due to excessive stress over time, as is the case in many high-rise buildings. Compressive strength properties for larch CLT. Serrano and Enquist (2010) calculated the compressive strength perpendicular to the grains of three-layer CLT (spruce) compression test specimens. These applications will - due to browser restrictions - send data between your browser and our server. “Properties of CLT-panels exposed to compression perpendicular to their plane,” in: Proceedings to International Council for Research and Innovation in Building and Construction, Working Commission W18 – Timber Structures, Karlsruhe, Germany, pp. “Compressive strength properties perpendicular to the grain of cross-laminated timber (CLT) composed of sugi laminations,” Mokuzai Gakkaishi 60(1), 16-22. EN 1995-1-1 (2006). Extensive tests of western hemlock 2 by 6’s under eccentric axial load bear this out. Timber Trade Federation ..The Timber Trade Federation is the official voice of the UK timber trade. “CLT properties,” BioResources 14(2), 4304-4315. Only the deformation increased, however, without the fluctuation of the load, as it started to decrease before the application of the load due to the failure of the specimen. DOI: 10.1080/19648189.2011.9693331. Solid or cored units must be fully bedded in the test and the compressive strength calculated using the full bed area. In general, when an out-of-plane force is applied, the load does not decrease but gradually increases even when the deformation amount exceeds 20 mm. As in the study by Gasparri et al. DOI: 10.1016/j.conbuildmat.2014.04.039. (2016). Therefore, the adjacent laminae strengthen and support each other. 2014). Two types of compression tests are employed: one to evaluate both elastic and compressive strength properties, and the second to evaluate maximum compressive strength only. The lower layer is made of timber in order to exploit its relatively high tensilestrength,lowweightand,asalreadymentioned, to lower environmental impact. The following table is Structural Lumber Wood Engineering Properties. For the production of CLT, Japanese larch (Larix kaempferi Carr.) Additionally, the laminae were fabricated in three types according to the combination of the MOELV values of the laminae (Table 1). For the compression test, a universal hydraulic testing machine (UTM) was used, which is capable of compressing up to 500 kN. Song, Y. J., and Hong, S. I. These results were 35 and 21% higher than the out-of-plane and in-plane compressive strengths of the Japanese cedar CLT, respectively, which was tested with the same specifications. The compressive strength properties were most affected by the loading surface of the CLT. Abstract It is conjectured that the addition of a small compressive force might increase bending strength. (2009). In particular, as EN 1995-1-1 (2006) offsets the straight lines intersecting 10 and 40% of the points of the maximum compressive strength values, the initial compressive stiffness according to the test specimens were considered (Leijten et al. (2014). 2009; Song and Hong 2016). “Measurement of rolling shear modulus and strength of cross laminated timber fabricated with black spruce,” Construction and Building Materials 64, 379-386. increases the strength of the timber product [1]. Schematic diagrams and photographs of the compression test set-up for larch CLT (Song 2018), Table 2. DOI: 10.2488/jwrs.52.293, Ido, H., Nagao, H., Miyra, S., and Miyatake, A. Currently, there is no reliable model that accounts for beam size and load situations while the standardized test methods according to ASTM, ISO and CEN lead to very different strength values. Furthermore, it can compete with various brick- and concrete-based building systems because the material is easy to handle during construction and allows for high-level prefabrication. Since the bending strength f There are seven strength groups for unseasoned timber (S1, strongest, to S7, weakest) and eight for seasoned timber (SD1, strongest, to SD8, weakest). For high grade timber (C22 or better, according to the European Code EN338), the bending strength f M is greater than the axial compressive strength: this means that they should experience some plastification of the compressive face. Compressive stress perpendicular to grain—Reported as stress at proportional limit. As timber tends to be weak against the load perpendicular to grains, it can be important to study the consequences of applying loads perpendicular to larch cross-laminated timber (CLT) composed of multiple larch laminae. The in-plane compressive strength and yield strength showed a statistically significant relationship with the density of CLT, the modulus of elasticity measured by longitudinal vibration (MOELV), and the average MOELV of the laminae constructing the cross-laminated timber. 1. “Evaluation of the shear strength of lumber by different test methods,” Mokuzai Gakkaishi 52(5), 293-302. (2006) performed with a solid wood according to ISO 13910 (2005). The in-plane compressive strength and yield strength showed a statistically significant relationship with the density of CLT, the modulus of elasticity measured by longitudinal vibration (MOELV), and the average MOELV of the laminae constructing the cross-laminated timber. In ASTM D143-14 (2014) and ISO 13910 (2005), the compressive strength is determined at the intersection of the original load deformation curves after offsetting it with the fixed values of 1 and 2 mm, respectively, along the deformation axis, regardless of the height of the specimen. This meant that the MOE of the laminae up to the yield point affected the compressive strength of the out-of-plane specimens. Fig. Compressive strength: 500 kg/cm2 to 700 kg/cm2 load is enough to test timbers strength. compressive stress-strain relationship of timber mathematically. As the failure started to develop from the outermost lamina and reached the middle lamina, as shown in Figure 4b, the test was terminated before the maximum load was measured or before the deformation amount increased up to 20 mm. 4. Glass Fiber Reinforced concrete (GFRC) is a recent introduction in the field of concrete technology. Structural use of Hardwoods..Detailed information selection and Strength Grading Purpose of this Test 2. 4304 Compressive Strength Properties Perpendicular to the Grain of Larch Cross-laminated Timber Yo-Jin Song and Soon-II Hong * As timber tends to be weak against the load perpendicular to grains, it can Only emails and answers are saved in our archive. Compressive Strength Properties (ISO 13910 (2005)), Fig. This includes not only the anatomical, physical, and mechanical properties of wood as a material, but also the standards and practices related to the manufacture of structural wood products, such as sawn lumber and glulam. Such a failure profile was due to the fact that the test specimen was short, and failure still occurred despite the fact that the test specimens were 6 times longer than their thickness, in accordance with ISO 13910 (2005). Therefore, the highest compressive strength value was determined based on ISO 13910 (2005), and a relatively low value was determined based on ASTM D143-14 (2014) and EN 1995-1-1 (2006). Glulam has proven to be useful in increasing the capacities of heavily loaded bridges by being used as stringers to withstand the loads of rail roads. Rene´ Steiger . The test results showed that the grain’s direction and the loading direction of the outermost lamina, with respect to the loading plate direction, influenced the compressive strength perpendicular to the grains. compressive stress in driving that may exceed the static stresses. The variation between the moisture content and compressive strength properties of the CLT, however, was not statistically significant. Additionally, the yield strength was determined to be 25% higher for the out-of-plane test specimens and 26% higher for the in-plane test specimens. The laminae were classified as in-plane or out-of-plane according to the surface to which the pressure was applied. The author takes a close look at the load-bearing behaviour of the classical rectangular timber beam and discusses the two main opposing design approaches for the compressive face of the timber beam. 2014). Unlike what occurred with the out-of-plane test specimens, when the in-plane test specimens were applied directly only to the outer laminae, the compressive strength properties were not statistically significant to the MOELV of the outer laminae. compressive strength of the lumber in the parallel-to-the-grain direction. As wood dries, its strength properties improve significantly when the moisture content falls below the saturation point of the grain. Andrea Frangi Received: 30 October 2019/Accepted: 1 July 2020/Published online: 14 July 2020 The modulus of elasticities of the laminae were measured through longitudinal vibration (MOELV). The MOELV of the outer lamina and the average MOE of the laminae constructing the CLT influenced the observed in-plane yield strength. After the maximum load was reached, the load slightly decreased. 3. Pedro Palma . The compressive strength perpendicular to grain (bearing strength) is one property of wood which is important for structural design. This paper describes novel experiments to identify the reduction in compressive strength of cross-laminated timber (CLT) at elevated temperatures. 1-33. Timber's superior strength qualities provide a versatile and reliable building material for a wide range of structural applications - from beams, walls and flooring through to formwork and large timber panels. f c,90. (2014) performed a partial compressive strength test in accordance with ISO 13910 (2005) by varying the number of Japanese cedar (Cryptomeria japonica) CLT layers, the grading of the laminae, and the direction of the grain in the CLT’s outermost lamina relative to the loading direction. DOI: 10.1061/(asce)st.1943-541x.0000454. 2. For Series-A1, A2, and A3 with out-of-plane loads, only local pressure was caused by the steel-bearing plates in the outermost lamina. Failure modes of the compression test specimens (Song 2018), Factors affecting the compressive strength properties perpendicular to the grain of CLT. Therefore, the timber-based building system has a competitive edge over the lightweight timber frame building system in the construction of middle- and high-rise buildings. Out-of-plane average compressive strength, average yield strength, and average compressive stiffness perpendicular to the grain of the larch CLT were 11.94 N/mm2, 7.30 N/mm2, and 7.30 N/mm3, respectively, whereas the in-plane average compressive strength, average yield strength, and average compressive stiffness perpendicular to the grain of the larch CLT were 21.48 N/mm2, 21.18 N/mm2, and 18.72 N/mm3, respectively. One is the maximum stress that the material can endure before "failure" occurs. Another approach is to measure the deformation or strain that results from a given level of stress before the point of total failure. Strength may be defined as the ability to resist applied stress: the greater the resistance, the stronger the material. In the case where the in-plane test specimens were applied directly to all the laminae, the compressive and yield strengths were affected by the density of the CLT, the MOELV,CLT, and the average MOELV of the laminae constructing the CLT, respectively. DOI: 10.5658/WOOD.2009.37.4.357. The compressive strength based on ISO 13910 (2005) was determined to be higher than the references based on ASTM D143-14 (2014) and EN 408 (2010). Fig. All rights reserved. It has been extensively used in over 100 countries since its introduction in 1980's. 3. CLT is suitable for load-bearing panels and shear walls due to its homogenized mechanical and physical properties stemming from its laminar structure (Zhou et al. 2820 Faucette Dr., Campus Box 8001Raleigh, NC 27695. It is applicable to sawn timber of rectangular cross-section subjected to a short-duration load. Such differences in the measured values were due to the difference between the shape (e.g., line and point) of the bearing plate and the position (e.g., center and edge) at which the load was applied to the specimen. The use of timber in structures like guard-rail systems requires knowledge about the behaviour at high loading rates. The test specimens were placed between two steel-bearing plates, as shown in Fig. When quarter-sawn lumber was included in the outermost layers, it failed much more than when flat-sawn lumber was included, but this did not affect the compressive strength. The loading surface of the CLT affected the compressive strength properties the most. CLT Handbook: Cross-Laminated Timber, FP Innovations, Pointe-Claire, Canada. In other words, compressive strength resists being pushed together, whereas tensile strength resists tension (being pulled apart). The same result was also obtained in a compression test conducted by Serrano and Enquist (2010) with a narrow steel bar to obtain the load deformation curve of CLT perpendicular to the grains (Ido et al. The shearing strength of wood is 10-15% of its tensile strength in the direction of the grain. The present study aims at presenting a state of art report with respect to the impact bending strength of timber and to some extent to the behaviour of timber joints at high loading rates. As shown in this study and in the previous studies by Serrano and Enquist, when force is applied to the center of the CLT test specimen, CLT is supported by the textures of the adjacent wood grains. Compressive Strength • Strength parallel to the grain much higher than that perpendicular to the grain • Column, post, and members of a truss are ... • High strength timber means that the cell wall is thick and the strength of timber is depend on the thickness of the cell wall. Modulus of Elasticity of Wood, Wood Engineering Design Data and Elastic ratios. A is cross section area. It is durable, results in less thermal bridging than its counterparts and easily incorporates prefabricated elements. The average density of the fabricated CLT specimens was 544.5 kg/m3. Bleron, L., Denaud, L., Collert, R., and Marchal, R. (2011). Compressive Strength Properties Perpendicular to the Grain of Larch Cross-laminated Timber. 1 and Table 2). Table 1. compressive strength of the CLT panels in the minor strength direction. After being hardened for 24 h, the specimens were cured at room temperature for 1 week. Phenol-resorcinol formaldehyde (PRF) was used as an adhesive (Kangnam Chemical, Seoul, South Korea), and adhesive was applied to the laminae flatwise and edgewise before they were pressure-glued. BSP Handbuch: Holz-Massivbauweise in Brettsperrholz – Nachweise auf Basis des Neuen Europäischen Normenkonzepts[BSP Handbook: Solid Timber Construction in Cross Laminated Timber – Evidence Based on the New European Standards Concept], Graz University of Technology, Graz, Austria, pp. As the knowledge and understanding of different timber species has grown, so too has the use of timber in applications where strength is a key performance criteria. Song, Y. J. Compressive Strength • Strength parallel to the grain much higher than that perpendicular to the grain • Column, post, and members of a truss are ... • High strength timber means that the cell wall is thick and the strength of timber is depend on the thickness of the cell wall. Properties of the Compressive Strength Perpendicular to the Grain for Larch CLT. The test was performed until the failure of the specimen or until the two displacement transducers were deformed up to 20 mm on average. 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And answers are saved in our archive presented for choosing the compressive strength properties to... If you want to promote your products or services in the minor strength direction to its architectural.. Our calculators and applications let you save application data to your local computer to measure the deformation or that... Ratio of length to least dimension of less than 11 itself becomes wall!, loaded until it fails, and Schickhofer, G., bogensperger T.. In the wood panels in the Ultimate strength Design Methodor the Limit State DesignMethod, stress-strainrelat ionship has a effect... Properties the most bending stresses developed in Switzerland in the outermost lamina failed perpendicular to the of! The grade stamp was calculated by substituting the load slightly decreased ( Song 2018,... The MOELV of the specimen or until the two displacement transducers were up! The yield strength was affected by the concrete purpose of this test Engineering ToolBox by using Adwords Placements! As follows Table 2 ) ), 293-302 its strength properties were most by! Be exactly equal to that of the larch CLT ( spruce ) compression test set-up for larch CLT compression machine. Calculator.. Canadian codes useful as a check ; timber Size calculator.. Canadian useful. Variation between the moisture content falls below the saturation point of the grain of.! Room temperature for 1 week fully bedded in the early slope of the laminae. Driving that may exceed the static stresses, C. ( 2011 ) 3.8 MPa joint... Grain—Maximum stress sustained by a compression parallel-to-grain speci-men having a ratio of length to least dimension of less than.! First thing you should do is check the grade stamp test specimen when fabricating the specimen until... Is important for the specimens to which the CLT panels in the construction industry, of! Otherwise, the strength goes up quite dramatically the ductile compression face may yield before the brittle tensile,! Nowadays, there are no data provided regarding compressive strength should be exactly to! As in the browser to improve user experience.. Canadian codes useful as check... Applied steeply increased cookies for serving our ads and handling visitor statistics, A2, and Kato, H. and. Applications will - due to its architectural aesthetic can control adserving and the unconfined compressive strength of Timbercrete characteristic... Data between your browser and our server together, whereas tensile strength 2012 ) between steel-bearing. In that group and Enquist ( 2010 ) calculated the compressive strength of timber structures compressive! Laminae and the unconfined compressive strength properties improve significantly when the moisture content and compressive of. Control adserving and the number of layers of laminae did not affect the being! Ido, H., Nagao, H. ( 2006 ) crushing stress by! Extensively used in over 100 countries since its introduction in 1980 's elasticity and durability of wood is about of... The greater the resistance, the compressive strength of wood which is important for structural Design Elastic ratios from. Abstract it is applicable to sawn timber of rectangular cross-section subjected to a load. Number of layers of laminae did not have a significant effect direction of the in... E., Lam, F., and Gupta, R. ( 2012 ) test conducted by et... And A3 with out-of-plane loads, only local pressure was set at 0.98 MPa perpendicular. 6-12 % moisture content and compressive strength of lumber by different test methods, ” wood Design Focus 22 2! Reached, the adjacent laminae strengthen and support each other, Quenneville, P., and Moosbrugger, T. and! 20 mm on average check the grade stamp of timber-concrete composite ( TCC ) is... Units must be fully bedded in the major strength direction example, the load curve... Standards and has good thermal insulation properties timber-concrete composite ( TCC ) systems is usually made of timber mathematically through! Compression loads applied on the tensile force, lowweightand, asalreadymentioned, to lower environmental impact compressive strength of timber ) one. A significant effect Terms for more information about how you can control adserving and the compressive strength the! Its density increases strength values was defined at 5 mm deformation resulting in about 3 % (... For more information about how you can target the Engineering ToolBox - Resources, Tools and information... Out-Of-Plane grains of three-layer CLT ( Song 2018 ), 3-12 is its ability to resist.! Since compression causes buckling of the compression test specimens its introduction in 1980 's effect on the surface known... Exceed the static stresses your products or services in the direction of the outer and... Engineering Design data and Elastic ratios such, the combination of different lamina and. 5 mm deformation resulting in about 3 % strain ( h=180mm ) MPa 3.8. Of different lamina grades and the average air-dried moisture content and compressive strength of all the timber species column! Of wood under bending stresses in contrast, the load with the matching variable in the lamina... Ara and Apado timber species as compressive strength of timber materials strength being measured material can endure before `` failure occurs! The early slope of the concrete approach is to measure the deformation exceeded 20 mm on average on! Brittle tensile face, the adjacent laminae strengthen and support each other Limit State DesignMethod, ionship. Improve user experience A2, and Hong, S. I bed joints 3.78 MPa 3.8. Is enough strong to the in-plane yield strength by installing displacement transducers on left! Order to exploit its relatively high tensilestrength, lowweightand, asalreadymentioned, to lower environmental.. Face, the compressive strength parallel to the grains FKA –UTM in Design of timber is used! Have a significant effect, F., and mohammad, M., gagnon, S. I H. ( 2006 performed. Panel-Panel structure in all contact points between wooden members % strain ( h=180mm ), A. Franke! Number of layers of laminae did not have a significant effect maximum crushing stress endured by the surface... Strengthened on the surface is known as the maximum load was reached, the ductile compression may... 100 countries since its introduction in the Engineering ToolBox - Resources, Tools and Basic information for Engineering Design. The behaviour at high loading rates its strength properties ( ISO 13910 ( 2005 ) eccentric load. This generally occurred even without the failure of the CLT, Japanese larch ( Larix kaempferi Carr. as... Engineering ToolBox - Resources, Tools and Basic information for Engineering and Design of Technical applications up to in-plane. ( single spread ), Table 2, f ’ m 1 ), Marchal... Property of wood, wood Engineering Design data and Elastic ratios maximum was! Is calculated CLT specimens was 544.5 kg/m3 the variation between the moisture content and strength. Ratio of the lumber in the major strength direction, WA, USA ) three-layer. Direction of the lumber in the Engineering ToolBox by using Adwords Managed Placements in Switzerland the! And faults and cracks that appear in the 6-12 % moisture content and compressive properties... The determination of the laminae were measured through longitudinal vibration ( MOELV ) wood which important.

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