Measurement of Rolling Shear Modulus and Strength of Cross-Laminated Timber Using Bending and Two-Plate Shear Tests


  • Q. Y. Zhou
  • M. Gong
  • Y. H. Chui
  • M. Mohammad


Rolling shear modulus, rolling shear strength, variable span bending test, two-plate shear test, shear analogy method, cross-laminated timber


Rolling shear properties of cross-laminated timber (CLT) are very low because of the configuration of the cross layer. In some applications, they are the key properties that govern the design and application of CLT. To explore an appropriate method for assessing the rolling shear properties of CLT, variable span bending tests and two-plate shear tests were conducted. Three types of down-scaled black spruce (Picea mariana) specimens, including wooden cross layer (WCL), steel-wood-steel (SWS), and three-layer down-scaled CLT (wood-wood-wood [WWW]), were fabricated using one-component polyurethane (for edge gluing) and epoxy adhesive (for steel and wood bonding). Deflection of a WWW specimen was predicted using a shear analogy method based on rolling shear modulus (Grt) of the cross layer obtained from the variable span bending test and two-plate shear test methods and was then compared with the deflection directly measured on WWW specimens. The test results showed that rolling shear modulus of WCL from the two-plate shear test was 72.61 MPa, which was more than twice that of the cross layer of SWS from the variable span bending test. Rolling shear strength of WWW measured using the three-point bending method was 2.74 MPa at a span-to-depth ratio of 6.


Aicher S, Dill-Langer G (2000) Basic considerations to rolling shear modulus in wooden boards. Otto-Graf-Journal 11:157-165.nANSI-APA (2012) Standard for performance-rated cross-laminated timber. ANSI/APA PRG 320-2012. APA-The Engineered Wood Association, Tacoma, WA.nASTM (2009) D198. Standard test methods of static tests of lumber in structural sizes. American Society for Testing and Materials, West Conshohocken, PA.nASTM (2011) D2718. Standard test methods for structural panels in planar shear (rolling shear). American Society for Testing and Materials, West Conshohocken, PA.nAyrilmis N, Winandy JE (2007) Effects of various fire-retardants on plate shear and five-point flexural shear properties of plywood. Forest Prod J 57(4):44-49.nBlaß HJ, Görlacher R (2000) Rolling shear in structural bonded timber elements. Pages 327-337 in S Aicher, ed, Proc Int. Conf. on Wood and Wood Fiber Composites, 13-15 April, University of Stuttgart, Otto-Graf-Institute, Department of Wood and Timber Engineering, Stuttgart, Germany.nChui YH (1991) Simultaneous evaluation of bending and shear moduli of wood and the influence of knots on these parameters. Wood Sci Technol 25(2):125-134.nCrespell P, Gagnon S (2010) Cross laminated timber: A primer. FPInnovations, Pointe-Clarie, Quebec, Canada.nFellmoser P, Blaß HJ (2004) Influence of rolling shear modulus on strength and stiffness of structural bonded timber elements. Paper 37-6-5 in HJ Larson and J Munch-Andersen, eds, Proc CIB-W18 Meeting, 31 August to 3 September 2004, Karlsruhe, Germany, Edinburgh, Scotland, UK.nKreuzinger H (1995) Mechanically jointed beams and columns. STEP 1: Timber engineering, Paper B11, Centrum Hout, Almere, The Netherlands, pp. 1-8.nMestek P, Kreuzinger H, Winter S (2008) Design of cross laminated timber (CLT). Paper 327 in Proc 10th World Conference in Timber Engineering, 2-5 June 2008, Curran Associates, Inc., Miyazaki, Miyazaki Prefectural Wood Utilization Research Center, Miyazaki, Japan.nNorlin LP, Lam F (1999) Fatigue behaviour and size effect perpendicular to the grain of laminated Douglas fir veneer. Mater Struct 32(4):298-303.nPirvu C (2011) Personal communication. FPInnovations, Vancouver, Canada.nReddy JN, Liu CF (1985) A higher-order shear deformation theory of laminated elastic shells. Int J Eng Sci 23(3): 319-330.nSteiger R, Gülzow A, Gsell D (2008) Non-destructive evaluation of elastic material properties of cross-laminated timber (CLT). Pages 29-30 in WF Gard and JWG van de Kuilen, eds, Proc International Conference COST E53, 29-30 October 2008, Delft, The Netherlands.nYawalata D, Lam F (2011) Unpublished research report submitted to Forestry Innovation Investment Ltd. Development of technology for cross laminated timber building systems. University of British Columbia, Vancouver, British Columbia, Canada.n






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