Factors Influencing Structural Performance of Finger-Jointed Chinese Fir Lumber

Abstract:

Structural Finger-jointed (FJ) lumber is a common building material used mainly in timber construction. The paper evaluated the factors influencing structural performances of FJ Chinese fir lumber. Lumber was sawn from the logs following a pattern typically used in China to maximize the volume of recovered sawn timbers. After kiln-drying, the rough-sawed lumber was planned to 4.5 cm thick, 9.0 cm wide and 100cm long. The lumber pieces were assigned to two groups according to their dynamical MOE. FJ lumber is produced by cutting a series of sloping fingers on the end of the wood pieces to be joined and interlocking the two pieces by MDI glue. Bending and tensile strengths of FJ lumber were tested. The results show that the structural performance of the MSR FJ lumber was increased effectively after these units were machine-graded in advance and the interaction of variables should be considered in the design of finger joints.

• Periodical: Applied Mechanics and Materials (Volumes 174-177)
• Pages: 635-640
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.174-177.635
• Online since: May 2012
• Authors: Hai Bin Zhou, Hai Qing Ren
• Keywords: Bending Strength, Finger-Jointed Lumber, Machine Grading, Tensile Strength

References

[1] F. Colling and J. Ehlbeck. Bearing strength of finger-joints for glulamination. Bauen mit Holz, 94:586-593 (1992). (in German).

[2] P. R. Fisette and W. W. Rice. An analysis of structural finger-joints made from two northeastern species. Forest Products Journal, 38(9):40-44 (1988).

[3] J. Ayarkwa, Y. Hirashima and Y. Sasaki. Effect of finger geometry and end pressure on the flexural properties of finger-jointed tropical African hardwoods[J]. Forest Products Journal, 50(11/12): 53-63 (2000).

DOI: 10.1080/10295925.2000.9631268

[4] E. Biblis and H. Carino. Factors influencing the flexural properties of fingerjointed southern pine LVL. Forest Products Journal, 43(1):41-46 (1993).

[5] B. Madsen and T.W. Littleford. Finger-joints for structural usage. Forest Products Journal, 12(2):68-73 (1962).

[6] D. B.Richards. Improved tips for finger-joints. Forest Products Journal, 13(6):250-251 (1963).

[7] M.L. Selbo. Effect of joint geometry on tensile strength of finger-joints. Forest Products Journal, 13(9):390-400 (1963).

[8] C. Bustos, R. Beauregard, M. Mohammad and R. Hernández. Structural performance of finger-joined black spruce lumber with different joint configurations. Forest Products Journal, 53(9):72-76 (2003).

[9] Forintek Canada Corp. Lumber and value-added wood products: Technology Roadmap. Ste-Foy, QC. 118 pp. (2001)

[10] Johannes Konnerth, Andreas Valla,Wolfgang Gindl, et al. Measurement of strain distribution in timber finger joints. Wood science and technology, 40(8): 631-636 (2006).

DOI: 10.1007/s00226-006-0090-9

[11] American Society for Testing and Materials. Standard methods of static tests of timbers in structural sizes. ASTM D 198 (2004).

[12] American Society for Testing and Materials. Standard practice for evaluating allowable properties for grades of structural lumber. ASTM D 2915 (2003).

[13] State Ministry of Construction. Code for design of timber structures. GB50005 (2005). (In Chinese)

[14] American Society for Testing and Materials. Standard test method for evaluating structural adhesives for finger jointing lumber. ASTM D 4688 (2005).

DOI: 10.1520/d4688-99