Effects of size, species and adjacent lamina on moisture related strain in glulam
Keywords:glulam, coefficient of moisture expansion, coefficient of moisture shrinkage, digital image correlation, strain
The goal of this study was to investigate the effects of size and species on moisture-related strain in glued–laminated timber (glulam). Swelling and shrinkage behaviors of different sizes (120 120, 180 180, and 180 240 mm2) of glulam made from larch and pine were measured using digital image correlation. A new approach to predict dimensional changes of glulam was developed by reflecting the nonlinear behavior of shrinkage based on MC change. It was compared with the existing method provided by the American Wood Council (AWC). Moisture-related strains of glulam were significantly influenced by size and species. Coefficients of swelling or shrinkage of glulam were determined to indicate statistical significance. When MC was changed from saturated condition to EMC of 12%, differences in dimensional changes in the width direction between experimental test and prediction results using the AWC method ranged from 87.7% to 260.0%. However, differences in dimensional changes in the width direction between experimental test and prediction results using the newly developed method ranged from 1.8% to 15.9%. Strains in the width direction of glulam could be affected by adjacent laminas along the glue line and the new approach could account for the effects. However, the AWC method could not reflect the effects of adjacent laminas along the glue line. Therefore, better prediction accuracy was achieved by using the new approach.
Anges V, Malo KA (2012) The effect of climate variations on glulam–An experimental study. Eur J Wood Wood Prod 70:603-613.
APA (1998) Dimensional changes in structural glued laminated timber. EWS Y260. Engineered Wood Systems, Tacoma, WA.
ASTM (2007) Standard test methods for direct moisture content measurement of wood and wood-base materials. D 4442-07. American Society for Testing and Materials, West Conshohocken, PA.
ASTM (2014a) Standard test methods for small clear specimens of timber. D143-14. American Society for Testing and Materials, Philadelphia, PA.
ASTM (2014b) Standard test methods for density and specific gravity (relative density) of wood and wood-based materials. D 2395-14. West Conshohocken, PA.
AWC (2015a) National design specification (NDS) for wood construction 2015 edition. American Wood Council, Leesburg, VA.
AWC (2015b) Manual for engineered wood construction 2015 edition. American Wood Council, Leesburg, VA.
Chen G, He B (2017) Stress-strain constitutive relation of OSB under axial loading: An experimental investigation. BioResources 12(3):6142-6156.
Cheng F, Hu Y (2011) Nondestructive test and prediction of MOE of FRP reinforced fast-growing poplar glulam. Compos Sci Technol 71:1163-1170.
Choong ET, Achmadi SS (2007) Effect of extractives on moisture sorption and shrinkage in tropical woods. Wood Fiber Sci 23(2):185-196.
Clair B, Jaouen G, Beauchene J, Fournier M(2003) Mapping radial, tangential and longitudinal shrinkages and relation to tension wood in discs of the tropical tree Symphonia globulifera. Holzforschung 57(6):665-671.
Cockrell RA (1943) Some observations on density and shrinkage of ponderosa pine wood. Am Soc Mech Eng Trans 65:729-739.
Fragiacomo M, Fortino S, Tononi D, Usardi I, Toratti T (2011) Moisture-induced stresses perpendicular to grain in cross-sections of timber members exposed to different climates. Eng Struct 33(11):3071-3078.
Gereke T, Schnider T, Hurst A, Niemz P (2009) Identification of moisture-induced stresses in cross-laminated wood panels from beech wood (Fagus sylvatica L.). Wood Sci Technol 43:301-315.
GOM mbH (2011) Aramis v6.3 and higher user manualsoftware. GOM mbH, Braunschwig, Germany.
Hann RA (1969) Longitudinal shrinkage in seven species of wood. Res. Note FPL-0203. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.
Hansmann C, Konnerth J, Rosner S (2011) Digital image analysis of radial shrinkage of fresh spruce (Picea abies L.) wood. Wood Mater Sci Eng 6:2-6.
Hernandez RE (2007) Swelling properties of hardwoods as affected by their extraneous substances, wood density, and interlocked grain. Wood Fiber Sci 39(1):146-158.
Hernandez RE, Pontin M (2006) Shrinkage of three tropical hardwoods below and above the fiber saturation point. Wood Fiber Sci 38(3):474-483.
ISO/TC (1982a) Wood—Determination of volumetric shrinkage. 4858. International Organization for Standardization, Geneva, Switzerland.
ISO/TC (1982b) Wood—Determination of volumetric swelling. 4860. International Organization for Standardization, Geneva, Switzerland.
Jeong GY, Park MJ (2016) Evaluate orthotropic properties of wood using digital image correlation. Constr Build Mater 113:864-869.
Jeong GY, Zink-Sharp A, Hindman DP (2009) Tensile properties of earlywood and latewood from loblolly pine (Pinus taeda) using digital image correlation. Wood Fiber Sci 41:51-63
Jeong GY, Zink-Sharp A, Hindman DP (2010) Applying digital image correlation to wood strands: Influence of loading rate and specimen thickness. Holzforschung 64:729-734.
Jonsson J, Svensson S (2004) A contact free measurement method to determine internal stress states in glulam. Holzforschung 58:148-153.
Keunecke D, Novosseletz K, Lanvermann C, Mannes D, Niemz P (2012) Combination of X-ray and digital image correlation for the analysis of moisture-induced strain in wood: Opportunities and challenges. Eur J Wood Wood Prod 70(4):407-413.
Lee SS, Jeong GY (2018) Effects of sample size on swelling and shrinkage of Larix kaempferi and Crytomeria japonica as determined by digital caliper, image analysis, and digital image correlation (DIC). Holzforschung 72:477-488.
Peng M, Ho YC, Wang WC, Chui YH, Gong M (2012) Measurement of wood shrinkage in jack pine using three dimensional digital image correlation (DIC). Holzforschung 66:639-643.
Silva C, Branco JM, Camoes A, Lourenco PB (2014) Dimensional variation of three softwood due to hygroscopic behavior. Constr Build Mater 59:25-31.
Stohr HP (1988) Shrinkage differential as a measure for drying stress determination. Wood Sci Technol 22:121-128.
USDA (2010) Wood handbook. General Technical Report GTR-190. U.S. Department of Agriculture, Forest Service, Madison, WI.
Welch MB (1932) The longitudinal variation of timber during seasoning. J Proc R Soc NSW 66:492-497.
Xavier J, De Jesus AMP, Morais JJL, Pinto JMT (2012) Stereovision measurements on evaluating the modulus of elasticity of wood by compression tests parallel to the grain. Constr Build Mater 26:207-215.
Yang TH, Wang SY, Tsai MJ, Lin CY (2009) The charring depth and charring rate of glued laminated timber after a standard fire exposure test. Build Environ 44:231-236.
Zhou HZ, Zhu EC, Fortino S, Toratti T (2010) Modelling the hygrothermal stress in curved glulam beams. J Strain Anal Eng Des 45:129-140.
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