Species, grading, and mechanical properties of locally sourced timber in the Joyabaj region of Guatemala
The purpose of this project was to research the timber used by EngineersÂ withoutÂ Borders (EWB) groups in the Joyabaj region of Guatemala. This project aimed to investigate the species of wood, evaluate the quality by assessing the distribution of timber grades, and determine mechanical properties. The results will aid EWB groups in the design of wood structures in the Joyabaj region of Guatemala.
Samples were collected for species investigation and mechanical testing. Species investigation was triangulated from interviews with the sawmill owner, construction foreman, testing by the USDA Forest Products Laboratory, and comparisons to literature. The results were inconclusive and indicated multiple species were intermixed at the sawmill with no distinction made when purchased. Timber quality was evaluated by using a visual grading guide developed by the authors to assess the distribution of grades within a large order of lumber. Static bending and compression parallel to grain tests were conducted to obtain modulus of rupture, compression parallel to grain, and modulus of elasticity. Specific gravity was also obtained.
The results indicate that three different species were collected. Ninety per cent (90%) of the timber was No. 3 or better and 50% to 80% was No. 2 or better depending on the size. Clear wood testing values were similar to those of Eastern White Pine. Structural design should be performed based on National Design Specification (NDS) design values for a No. 3 or No. 2 Eastern White Pine, depending on the degree of wood selection in the construction process.
American Wood Council 2014, National Design Specification (NDS) Supplement: Design Values for Wood Construction 2015 Edition, American Wood Council, Leesburg, Virginia.
American Wood Council 2016, National Design Specification (NDS) for Wood Construction 2015 Edition, American Wood Council, Leesburg, Virginia.
ASTM International 2007, ASTM D4442-07: Standard Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials, ASTM International, West Conshohocken, Pennsylvania.
ASTM International 2009, ASTM D143-09: Standard Test Methods for Small Clear Specimens of Timber, West Conshohocken, ASTM International, Pennsylvania.
Bogle-Boesiger, L 2016, â€˜Identification and structural properties of untreated lumber from the Joyabaj Region of Guatemalaâ€™ Masters thesis, Milwaukee School of Engineering.
Breyer, D Cobeen, K Fridley, K & Pollock, D 2015, Design of wood structures - ASD/LRFD, McGraw-Hill Education LLC, New York
Chudnoff, M 1984, Tropical timbers of the world, Washington, Department of Agriculture - Forest Service, District of Columbia, United States of America
CONCYT 1999, Coniferas de Guatemala â€“ Base de Datos Forestales DATAFORG, Guatemala: Consejo Nacional de Ciencia y Tecnologia, Guatemala.
Kretschmann, D 2010, â€˜Mechanical properties of woodâ€™ in RJ Ross (ed.), Wood Handbook - Wood as an Engineering Material, U.S. Department of Agriculture - Forest Service- Forest Products Laboratory, Madison, Wisconsin
Glass, S & Zelinka, S 2010, â€˜Moisture relations and physical properties of woodâ€™, Wood Handbook - Wood as an Engineering Material, U.S. Department of Agriculture - Forest Service- Forest Products Laboratory, Madison, Wisconsin
Rosales, A, Morales, G & Green, D 1995, â€˜Properties of Guatemala 2 by 4â€™sâ€™, Forest Products Journal, vol. 45, no. 10, pp. 81-84.
Southern Pine Inspection Bureau (SPIB) 2014, Standard grading rules for southern pine lumber, Southern Pine Inspection Bureau, Pensacola, Florida.