DEVELOPMENT OF A CORRELATION MODEL FOR TORSIONAL SHEAR MODULUS PROPERTIES BETWEEN STRUCTURAL SIZE SPECIMENS BASED ON EN 384:2016 AND SMALL CLEAR SPECIMENS (MS544: PART 2)
DOI:
https://doi.org/10.11113/jurnalteknologi.v86.20819Keywords:
Shear modulus, torsion testing, structural dimension, small defect-free samples, tropical hardwood timberAbstract
In timber design, the shear modulus of timber beams is vital for ensuring torsional stability and minimizing issues with vibrational serviceability. Typically, the shear modulus is determined by the ratio of E to G, which is 16:1. However, the bending test introduces a combination of flexural and shear stresses, making it challenging to accurately assess the pure shear properties and shear stiffness value. The most recent British Standard, BS EN 408:2012, advocates for the torsion test as the standard method for characterizing properties of structural size timber or timber composite materials. Currently, this method has garnered limited attention in Malaysia. The main aim of this study is to investigate the torsional shear modulus of Malaysian tropical timbers categorized into different strength groups (SG), such as Balau (SG1), Kempas (SG2), Kelat (SG3), Kapur (SG4), Resak (SG4), Keruing (SG5), Mengkulang (SG5), Light Red Meranti (SG6), and Geronggang (SG7). Torsion tests were conducted following BS EN 408 standards, and the resulting shear modulus values were compared with modulus of elasticity published in MS554: Part 2. The results revealed that the shear modulus values for all timbers exhibit the following order: Balau > Kempas and Resak > Kelat, Kapur, Keruing, and Mengkulang > Geronggang > Light Red Meranti. The modulus of elasticity to shear modulus ratio for all species falls within the range of 17:1 to 29:1, with an average ratio of 21:1, markedly exceeding the conventional E:G ratio of 16:1.
References
British Standards Institution. 2010. BS EN 408: 2010. Timber structures - structural timber and glued laminated timber - Determination of some physical and mechanical properties perpendicular to the grain. London: BSI.
Green, D. W., Winandy., Kretshmann, D. E. 1999. Mechanical Properties of Wood. Chapter 4 Wood-as an Engineering Material. Forest Product Laboratory, Madison Wisconsin.
Schlotzhauer, P., Nelis, P. A., Bollmus, S., Gellerich, A., Militz, H., Seim, W. 2015. Effect of Size and Geometry on Strength Values and MOE of Selected Hardwood Species. Wood Material Science & Engineering. 1-9.
Yang, N., Zhang, L. 2018. Investigation of Elastic Constants and Ultimate Strengths of Korean Pine from Compression and Tension Tests. Journal of Wood Science. 64(2): 85-96.
Khokhar, A. M. 2011. The Evaluation of Shear Properties of Timber Beams Using Torsion Test Method. Doctor of Philosophy Thesis, Edinburgh Napier University Edinburgh, Scotland, United Kingdom.
Ahmed Mohamed, A., Deng, Y., Zhang, H., Wong, S.H. F., Uheida, K., Zhang, Y.X., Mei‑Chun Zhu, M-C., Lehmann, M., Quan, Y. 2021. Photogrammetric Evaluation of Shear Modulus of Glulam Timber Using Torsion Test Method and Dual Stereo Vision System. European Journal of Wood and Wood Products. 79: 1209-1223.
Divos, F., Tanaka, T., Nagao, H., Kato, H. 1998. Determination of Shear Modulus on Sonstruction Size Timber. Wood Science and Technology. 32(06): 393-402.
Chui Y. H. 2002. Application of the Ribbed-Plate Theory of Predict Vibrational Serviceability of Timber Floor Systems. The Proceedings of 7th World Conference on Timber Engineering WCTE. 4: 87-93.
Hindman D., Manbeck H. B., Janowiak J. J. 2005. Torsional Rigidity of Rectangular Wood Composite Materials. Wood and Fiber Science. 37(2): 283-291.
Ukyo, S., Ido, H., Nagao, H., Kato, H. 2010. Simultaneous Determination of Shear Strength and Shear Modulus in Glued-Laminated Timber Using A Full-Scale Shear Block Specimen. Journal of Wood Science. 56(3): 262-266.
Piotr Bilko, P., Skoratko, A., Rutkiewicz, A., Małyszko, L. 2021. Determination of the Shear Modulus of Pine Wood with the Arcan Test and Digital Image Correlation. Materials. 14(2): 468.
Keenen, F. J. 1974. Shear Strength of Wood Beams. Forest Products Journal. 24(9): 63-70.
Puaad, M. B. F. M. 2013. Bending and Compressive Properties of Malaysian Timber in Structural Size. Master of Science Thesis. Faculty of Civil Engineering. Universiti Teknologi Mara, Shah Alam, Selangor. Malaysia.
Malaysian Standard. 2017. MS 544 Part 2: 2017 - Code of Practice for Structural Use of Timber. Department of Standard, Malaysia.
British Standards Institution. 1995. BS EN408:1995. Timber Structures - Structural Timber and Glued Laminated Timber - Determination of Some Physical and Mechanical Properties Perpendicular to the Grain. London: BSI.
Ahmad, Z., Bon, Y. C., Wahab, E. S. A. 2003. Tensile Strength Properties of Tropical Hardwoods in Structural Size Testing. International Journal of Basic & Applied Sciences IJBAS-IJENS. 10(3): 1-6.
Sheikh, S., Ahmad, Y. 2015. Flexural Timber Design to Eurocode 5 and the Malaysian Timber Code MS 544: 2001. Malaysian Journal of Civil Engineering. 2(Special Issue 1): 207-223.
Puaad, M. B. F. M., Ahmad, Z., Talip, A. R. A., Salleh, M. Z. M., Mohammad, S. N. 2020. Torsional Shear Strength Properties of Malaysian Tropical Timber in Structural Size. Jurnal Teknologi. 82(5): 1-10).
Ido, H., Nagao, H., Kato., H. 2007. Comparison between Compression Strength Perpendicular to The Grain and Shear Strength Parallel to The Grain of Western Hemlock [tsuga heterophylla] Lumber. Bulletin of the Forestry and Forest Products.
Ahmad, Z. San, H. P., Md Tahir, P. 2013. Laminated Veneer Lumber Made from Tropical Forest Trees (Mechanical Properties). UiTM Press. UiTM Shah Alam, Malaysia.
Mohamed, A. 2023. Standard Test Methods for Elastic and Shear Properties. In Zhang, J (Ed.). Current Applications of Engineered Wood. IntechOpen.
British Standard. 2004. BS EN 1995-1-1:2004, Eurocode 5 - Design of Timber Structures-Part 1-1: General Common Rules and Rules for Buildings. London: BSI.
Foschi, R. O. 1982. Structural Analysis of Wood Floor Systems. Journal of the Structural Division. 108(7): 1557–1574.
Harrison, K. S. 2006. Comparison of Shear Modulus Test Methods. MSc Thesis. Blacksburg, VA, USA.
Malaysian Standard. 2003. MS 1714:2003- Specification for Visual Strength Grading of Tropical Hardwood Timber, Department of Standard. Malaysia.
British Standard. 2002. BS 5268 - Part 2:2002- Structural use of timber: Part 2: Code of Practice for Permissible Stress Design, Materials and Workmanship.
Chu, Y. P., Ho, K. S., Midon, M. S., Malik, A. R. A. 1997. Timber Design Handbook. FRIM, Malaysia. Kepong
European Standard. 2003. EN384:2003 - Structural Timber-determination of Characteristic Values of Mechanical Properties and Density. European Committee for Standardization, Brussels, Belgium.
European Standard. 2016. EN14358:2016 - Timber Structures — Calculation and Verification of Characteristic Values.
European Standard. 2009. EN338:2009 - Timber Structures - Strength Classes. European Committee for Standardization, Brussels, Belgium.
Gupta, R., Heck, L. R., Miller, T. H. 2002. Experimental Evaluation of the Torsion Test for Determining Shear Strength of Structural Lumber. Journal of Testing and Evaluation. 30(4): 283-290.
Bodig, J. and Jayne, B. A. 1982. Mechanics of Wood and Wood Composites. Van Nostrand Reinhold. 712.
Za’ba, N. I. L. 2018. Tensile Strength Class System for Malaysian Hardwoods According to European Standards EN 384 and EN 408. Doctor of Philosophy Thesis. Faculty of Civil Engineering. Universiti Teknologi Mara, Shah Alam, Selangor. Malaysia.
Azmi, A. 2019. Tensile Strength Class System for Malaysian Hardwoods According to European Standards EN 384 and EN 408. Doctor of Philosophy Thesis. Faculty of Civil Engineering. Universiti Teknologi Mara, Shah Alam, Selangor. Malaysia.
Baharin, A. 2020. Development of Characteristic Value of Bending Strength Properties for Malaysia Tropical Hardwood Timber in Structural size In Accordance with Eurocode 5. Doctor of Philosophy Thesis. Faculty of Civil Engineering. Universiti Teknologi Mara, Shah Alam, Selangor. Malaysia.
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