Measurement and prediction of lateral torsional buckling loads of composite wood materials: I-joist sections

Daniel P. Hindman, Harvey B. Manbeck, John Jack Janowiak

Research output: Contribution to journalReview article

13 Citations (Scopus)

Abstract

Previous studies have shown a difference in the behavior of solid-sawn lumber and structural composite lumber (SCL) materials in terms of the elastic constant ratios and in the lateral torsional buckling behavior. The increased use of wood composite I-joists, many with SCL materials as flange stock, for longer span applications gives increased importance to the lateral torsional buckling determination for these materials. The current load resistance factor design (LRFD) equations for I-joist lateral buckling assume that the compression flange acts as a column restrained in the direction of the web. An unbraced cantilever beam test method was used to determine the critical buckling load (CBL) of two I-joist materials with SCL flanges. These measured CBLs were then compared to predicted CBLs using current LRFD design equations and elastic beam buckling theory. The current LRFD design equation CBLs were, on average, at least 77 percent less than the measured CBLs, while the elastic beam buckling CBL predictions were on average 28 percent less than the measured CBLs. The low CBL predictions using current LRFD equations demonstrate that assumption of lateral buckling behavior resembling the buckling of the compression flange supported in the direction of the web is not a satisfactory model. An elastic buckling solution incorporating the off-axis bending and torsional rigidity of the composite cross section of the I-joist provided a more reasonable CBL prediction.

Original languageEnglish (US)
Article number9859
Pages (from-to)43-48
Number of pages6
JournalForest Products Journal
Volume55
Issue number10
StatePublished - Oct 1 2005

Fingerprint

buckling
Buckling
Wood
lumber
prediction
Composite materials
Lumber
R Factors
Flanges
material
compression
critical load
Cantilever beams
Elastic constants
rigidity
Rigidity
cross section
testing

All Science Journal Classification (ASJC) codes

  • Forestry
  • Materials Science(all)
  • Plant Science

Cite this

Hindman, Daniel P. ; Manbeck, Harvey B. ; Janowiak, John Jack. / Measurement and prediction of lateral torsional buckling loads of composite wood materials : I-joist sections. In: Forest Products Journal. 2005 ; Vol. 55, No. 10. pp. 43-48.
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abstract = "Previous studies have shown a difference in the behavior of solid-sawn lumber and structural composite lumber (SCL) materials in terms of the elastic constant ratios and in the lateral torsional buckling behavior. The increased use of wood composite I-joists, many with SCL materials as flange stock, for longer span applications gives increased importance to the lateral torsional buckling determination for these materials. The current load resistance factor design (LRFD) equations for I-joist lateral buckling assume that the compression flange acts as a column restrained in the direction of the web. An unbraced cantilever beam test method was used to determine the critical buckling load (CBL) of two I-joist materials with SCL flanges. These measured CBLs were then compared to predicted CBLs using current LRFD design equations and elastic beam buckling theory. The current LRFD design equation CBLs were, on average, at least 77 percent less than the measured CBLs, while the elastic beam buckling CBL predictions were on average 28 percent less than the measured CBLs. The low CBL predictions using current LRFD equations demonstrate that assumption of lateral buckling behavior resembling the buckling of the compression flange supported in the direction of the web is not a satisfactory model. An elastic buckling solution incorporating the off-axis bending and torsional rigidity of the composite cross section of the I-joist provided a more reasonable CBL prediction.",
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Measurement and prediction of lateral torsional buckling loads of composite wood materials : I-joist sections. / Hindman, Daniel P.; Manbeck, Harvey B.; Janowiak, John Jack.

In: Forest Products Journal, Vol. 55, No. 10, 9859, 01.10.2005, p. 43-48.

Research output: Contribution to journalReview article

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