2011; Leijten et al. 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). Series-A3 and B3 randomly combined laminae from 7 to 19 GPa. It was reported after the test that the compressive strength was influenced by the size of the area to which the load was applied, the grain direction of the outermost lamina of the CLT, and the distance from the compressed area to the end-plane of the specimen to which the load was applied (Serrano and Enquist 2010). 3. “Eurocode 5 – Design of timber structures – Part 1-1: General common rules and rules for buildings,” European Committee for Standardization, Brussels, Belgium. It is highest parallel to the grain and lowest perpendicular to the grain, and for other angles has intermediate values. The loading surface of the CLT affected the compressive strength properties the most. in compression across the grain, showing crushing of blocks under bearing plate. (2011), cubic CLTs tested in accordance with EN 408 (2010) demonstrated 27% greater compressive strength and 50% greater compressive stiffness than glulam. Wood is a structural material with many appealing properties. See the answer. 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. The characteristic strength values for compression perpendicular to grain as they appear in EN 338 (structural timber) and prEN 1194 (glulam) are currently up for discussion. Series-A2 and B2 were the test specimens that combined the MOELV of the longitudinal laminae with 14 GPa and the MOELV of the transverse laminae with 9 GPa, respectively. According to the tests carried out as presented in this rapport, support length are of importance when determining timber compression strength perpendicular to the grain. Statistical Significance between the Parameters and the Compressive Strength Properties. It is expressed using a number of measures, such as its density (the weight per a given volume); its compressive strength (or how great a weight a load of wood can bear parallel to the grain before it ruptures); its bending strength (a load of wood perpendicular to the grain); and its hardness. 1-11. Above this point the material behaves plastically and will not return to its original length once the load is removed. Compression parallel to the grain shortens the fibers in the wood lengthwise. The compressive strength of timber in the direction perpendicular to the grain (CPG), f c,90, k is one of the crucial parameters affecting the load-bearing capacity of wood. The compressive strength of the material would correspond to the stress at the red point shown on the graph. Tests of compression perpendicular to the grain were carried out on laminated veneer lumber (LVL) and timber. Properties of the Compressive Strength Perpendicular to the Grain for Larch CLT. Serrano and Enquist (2010) calculated the compressive strength perpendicular to the grains of three-layer CLT (spruce) compression test specimens. 1-40. In design of timber structures the compressive strength perpendicular to the grain is important. COMPRESSION STRENGTH PERPENDICULAR TO GRAIN IN CROSS-LAMINATED TIMBER (CLT) Erik Serrano 1 and Bertil Enquist 2 ABSTRACT: The work presented involved testing of the compression strength of square specimens made from three- layer CLT. bending strength, tensile strength perpendicular to grain, and hardness. Bleron, L., Denaud, L., Collert, R., and Marchal, R. (2011). The loading rate was set at 3 mm/min. 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. 1-15. Compressive strength properties for larch CLT. The compressive strength properties were most affected by the loading surface of the CLT. The species tested were sugi, radiata pine, karamatsu, akamatsu, and dahurian larch; two sets of sugi specimens were tested, with the sugi LVL products being manufactured in different plants. In the experiment, testing the compressive strength of wood, which is the measurement of the largest compression force the material can withstand before it loses its shape or fails, the students used two samples (wood parallel and perpendicular to the grain). 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. 1-33. There is no clearly defined ultimate stress for this property. The CLT’s loading surface had the greatest effect on all the compressive strength properties, but the CLT’s moisture content was not statistically significant with any compressive strength property. The test specimens were placed between two steel-bearing plates, as shown in Fig. 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. The first effect of compression across the grain is to compact the fibers, the load is irregularly increasing as the. The yield strength values in this study were 34% higher than those obtained by Sereno and Enquist (2010) and Gasparri et al. 2 Analogy among compressive strength test and embedment strength test 582 Wood Sci Technol (2010) 44:579–595 123. As such, the compressive strength was determined through a method more rigorous than the previous two methods. Expert Answer . 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/mm 2, 7.30 N/mm 2, and 7.30 N/mm 3, 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/mm 2, 21.18 N/mm 2, … This is very useful information about Compression testing. EN 408 (2010). Compression strength testing. 4. The main aim of his study however, was to verify the relation between the compressive strength and the wood density. The in-plane test specimens were made to have five layers because the three-layer in-plane specimen from the preliminary test demonstrated low accuracy due to its rotation during the compression test. Definition of the compression load perpendicular to the grain in accordance with ISO 13910 (ISO 13910 (2005)). Perpendicular to the grains. Discuss if the wooden column can accommodate the given load. This linear region terminates at what is known as the. How do you calculate corrosion? There is no clearly defined ultimate stress for this property. When used as ties in railways or as bridges decks, wood is request with compressive loads in direction perpendicular to the grain. In uniform, flawless wood, the bending strength is as great as the tensile strength. The average density of the fabricated CLT specimens was 544.5 kg/m3. The bearing strength is important for the behavior of the structure in all contact points between wooden members. 1. In contrast, the combination of different lamina grades and the number of layers of laminae did not have a significant effect. Cross-laminated timber (CLT) is an engineered wood panel made of laminae with thicknesses of around 20 to 60 mm, which are laminated orthogonally to the fiber direction to resist in the positive direction of the load (Song and Hong 2018). Compressive Or Crushing Strength Compression across the grain is very closely related to hardness and transverse shear. “Bearing strength capacity of continuous supported timber beams: Unified approach for test methods and structural design codes,” Journal of Structural Engineering 138(2), 266-272. The compressive strength (fc, 90), yield strength (fc, 90, y), and compressive stiffness (Kc) were calculated based on the load deformation curve of the test according to ISO 13910 (2005) (Fig. “Standard test methods for small clear specimens of timber,” ASTM International, West Conshohocken, PA. Augustin, M., Ruli, A., Brandner, R., and Schickhofer, G. (2006). Fig. After being hardened for 24 h, the specimens were cured at room temperature for 1 week. The following are the results that were obtained. (2014). Wood Handbook--Chapter 4--Mechanical Properties of Wood Mechanical Properties of Wood David W. Green, Jerrold E. Winandy, and David E. Kretschmann . Strength data for clear, defect-free speci­ mens for a few species are given in Table 2. The wooden column can accommodate the given load (1450 kN) because its compressive strength is less than the maximum strength of the wood sample. properties. structural applications are given only for directions parallel to grain (longitudinal) and perpendicular to grain (radial and tangential). 440. 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. The compressive strength of wood depends on the direction of the grain with respect to the direction of the applied force. This generally occurred even without the failure of the specimen if the deformation exceeded 20 mm. 2012). In the wood being tested along the grain, the deformation is smaller than the deformation of the wood across the grain; even it has greater loads applied on the wood. The present research is unique because the specimens were tested in the climatic chamber while at the desired temperature. This CLT construction method relies on a panel-panel structure in which the CLT itself becomes a wall, a floor, and a roof. The determination of the compressive strength according to EN 1995-1-1 (2006) and ASTM D143-14 (2014) is similar to the determination of the yield strength according to ISO 13910 (2005). The compression strength of air-dry wood is about half of the corresponding tensile strength. Tensile strength also depends on the density of the wood: for example, the tensile strength of the spring wood in a pine is only 1/6 of that of summer wood. Compression tests were conducted perpendicular to the in-plane and out-of-plane grains of Japanese larch CLT. The calculations models for bearing strength have been a subject of discussion for many years and the different Abstract. tensile strength perpendicular to the grain and side hardness. In the wake of the green building movement in the early 2000s, however, the research and construction in this area began to increase thanks to the improved production efficiency of CLT, the product certification, and the improved marketing and distribution efforts (Mohammad et al. It is highest parallel to the grain and lowest perpendicular to the grain, and for other angles has intermediate values. “Compressive strength properties perpendicular to the grain of cross-laminated timber (CLT) composed of sugi laminations,” Mokuzai Gakkaishi 60(1), 16-22. “Evaluation of the shear strength of lumber by different test methods,” Mokuzai Gakkaishi 52(5), 293-302. In the experiment, testing the compressive strength of wood, which is the measurement of the largest compression force the material can withstand before it loses its shape or fails, the students used two samples (wood parallel and perpendicular to the grain). The graph is also one of the proofs where in parallel, has lesser value of strains than in the perpendicular. 4c, d). The students conclude that the strength of wood parallel to the grain subjected under compressive load is greater than that of the strength of wood perpendicular to the grain subjected under compressive load. Compression stress shortens or compresses the material. Figure 3-5- The three principal axes of wood with respect to grain direction and growth rings. Previous Research Studies Overview. (2016). After curing, the out-of-plane specimens were shaved down to a piece measuring 80 mm (h) × 150 mm (w) × 480 mm (l) while the in-plane specimens were shaved down to a piece measuring 80 mm (h) × 135 mm (w) × 480 mm (l). Additional measurements are often made to evaluate work to maximum load in bend- ing, impact bending strength, tensile strength perpendicular to grain, and hardness. Sometimes known as compression strength parallel to the grain, this is a measurement of the wood’s maximum crushing strength when weight is applied to the ends of the wood (compression is parallel to the grain). Table 1 Partial compressive strength perpendicular to the grain of specimens with/without pith Full size table To meet objective (2), as shown at Experiment II in Fig. 1. Failure modes of the compression test specimens (Song 2018), Factors affecting the compressive strength properties perpendicular to the grain of CLT. Compressive strength of wood is measured by loading a block of wood parallel to the grain until it breaks, and the bending strength is measured by loading a block perpendicular to the grain. The variation between the moisture content and compressive strength properties of the CLT, however, was not statistically significant. Table 5. The compression strength perpendicular to the grain is one of the important timber properties for structural design. Table 1. Exceeding the strength value will not only lead to large deformations and thus a serviceability issue, but it can also lead to a failure and thus a safety issue. In cross grain boards, the board was cut "across the grain," roughly perpendicular to the tree trunk. It is the stress obtained at the intersection with a 0,01h0 offset line parallel to the linear part of the stressstrain curve, where h is the height of the specimen (figure 2). Gasparri, E., Lam, F., and Liu, Y. Compressive strength parallel to grain—Maximum . Another cause of such a difference in compressive strength is the difference in the determination method of the strength properties of each test criterion for the load-strain curves. The yield strength was calculated as follows. . is increased. 2014). If the specimen lies on a flat surface and the load is applied to only a portion of the upper area, the bearing plate indents the wood, crushing the upper fibers without affecting the lower part. Buildings 2020, 10, 14 3 of 14 and wood density evaluation, (2) monotonic compression tests perpendicular to the grain. 2012). “Performance evaluation of the bending strength of larch cross-laminated timber,” Wood Research 63(1), 105-115. The in-plane compressive and yield strengths showed statistically significant relationships to the density of the CLT, the modulus of elasticity measured by longitudinal vibration (MOELV), and the average MOE of the laminae when constructing the CLT. (2009). Compression parallel to the grain shortens the fibers in the wood lengthwise. DOI: 10.5658/WOOD.2009.37.4.357. A total of 10 specimens were fabricated for each series. The bearing strength is important for the behavior of the structure in all contact points between wooden members. There are two ways in which wood is subjected to stress of this kind, namely, (1) with the load acting over the entire area of the specimen , and (2) … 1-16. The in-plane compressive strength was 1.8 times greater than the out-of-plane compressive strength, and the yield strength and stiffness were 2.9 and 2.5 times greater, respectively. This is certainly a useful yardstick of strength but is by no means the only one. A board rated at 2.0E is twice as stiff as one rated at 1.0E. The difference in compressive strength between the out-of-plane and in-plane test specimens to which the load was applied was large, but there was no difference in strength according to the MOELV combination. 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. When used as ties in railways or as bridges decks, wood is request with compressive loads in direction perpendicular to the grain. They performed a full compression and line-type compression test on the plane perpendicular to the grains of each test specimen, according to EN 1995-1-1 (2006). Wood is stronger in resisting shear across the grain than it is parallel to the grain. 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. Strength of wood is often thought of in terms of bending strength. ISO 13910 (2005). The aim of this research is determining the compressive perpendicular to the grain strength (f c90 ) of two Brazilian exotic wood species. “Timber structures-Structural timber and glued laminated timber-Determination of some physical and mechanical propertied,” European Committee for Standardization, Brussels, Belgium. For the production of CLT, Japanese larch (Larix kaempferi Carr.) 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. So, better take any challenges as your stepping stone to become a better person. Bogensperger, T., Augustin, M., and Schickhofer, G. (2011). The ratio between the values The students observed that during the testing, the wood has shortened. Serrano, E., and Enquist, B. Tensile strength in the direction of the grain is usually 10-20 times more than its strength perpendicular to the grain. There is a standard test specimen as shown in Figure A1, but there are few data actually available. DOI: 10.1016/j.conbuildmat.2014.04.039. The compressive strength test of the larch CLT for loads perpendicular to the grains was conducted in accordance with the ISO 13910 (2005) standard. This results in the least wood strength, and boards are rarely cut this way on purpose. In the experiment, testing the compressive strength of wood, which is the measurement of the largest compression force the material can withstand before it loses its shape or fails, the students used two samples (wood parallel and perpendicular to the grain). 0. 2014). The laminae were classified as in-plane or out-of-plane according to the surface to which the pressure was applied. In contrast, there was no difference in maximum load between the in-plane specimens with over 20 mm deformation and the other in-plane specimens with less than 20 mm deformation. 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. Table 4. 2. Song, Y. J., and Hong, S. I. between 0 (parallel to the grain) and 90 (perpendicular to the grain) were chosen for compression test. Both are measured in pounds per square inch (psi). DOI: 10.2488/jwrs.52.293, Ido, H., Nagao, H., Miyra, S., and Miyatake, A. A number of other strength criteria are described below. The gathered data on the table show that the compressive strength of the wood being tested along the grain is greater than the compressive strength of the wood being tested across the grain. Figure 3 shows the load deformation curves from the compression test. This gets reported as a proportional value. The material has in general a high strength to weight ratio, it is a renewable resource and it is also by many considered to be aesthetically appealing. Tests of compression perpendicular to the grain were carried out on laminated veneer lumber (LVL) and timber.