Skip to page content
USDA Forest Service
  
Treesearch

Research & Development Treesearch

 
Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Northern
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help
 

Science.gov - We Participate


USA.gov  Government Made Easy


Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.
20090-6090

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (404 KB bytes)

Title: Flexural properties of glued-laminated Southern pine beams with laminations positioned by visual-stiffness criteria

Author: Moody, R. C.; Bohannan, Billy;

Date: 1970

Source: Research paper FPL no. 127. Madison, WI : USDA, Forest Service, Forest Products Laboratory. 20 pages.

Publication Series: Research Paper (RP)

Description: To establish the effect of using modulus elasticity in addition to visual grade as criteria for the positioning of laminations in laminated beams, an experimental study on southern pine members was conducted. The beams were manufactured in accordance with current specifications for glued-laminated southern pine timber, except that (a) minimum-quality tension laminations meeting AITC 301-67were used and (b) restrictions were placed on the modulus of elasticity of all laminations. Current specifications require that boards lie positioned in laminated members on the basis of their visual grades. The use of modulus of plasticity in addition to visual grading in selecting quality laminations for highly stressed areas should provide for better assessment of lamination quality and result in stronger and stiffer laminated timber members. Five glued-laminated southern pine beams, 5-1/4 inches 24-3/8inches deep, and 40 feet long, were manufactured using the dual criteria for positioning of laminations. Results of bending tests were compared to data reported in USDA Forest Service Research Paper FPL 113 for comparable beams made using only visual grading requirements. In both sets of beams, the tension laminations were selected to represent near minimum visual quality for the AITC 301-67 grade. The average modulus of elasticity of the beams manufactured using both visual and stiffness criteria was 12 percent higher than that for beams using only the visual criteria. This agreed with the theoretically expected increase in modulus of elasticity. The average modulus of rupture of the visual-stiffness beams was 14 percent higher than that for the visual-only beams. However, the minimum strength for each group was approximately equal.

Keywords: Modulus of elasticity, beams, bending, stiffness, strength, laminated wood, glulam, visual grades, tension lamination, modulus of rupture, deflection limitations

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

XML: View XML

Citation:


Moody, R. C.; Bohannan, Billy 1970. Flexural properties of glued-laminated Southern pine beams with laminations positioned by visual-stiffness criteria. Research paper FPL no. 127. Madison, WI : USDA, Forest Service, Forest Products Laboratory. 20 pages.

 


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.