Comparison of creep/duration of load performance in bending of Parallam® parallel strand lumber to machine stress rated lumber
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Craig, Bruce A.
issued: 2010-07-07T22:16:08Z
issued: 1986
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: A comparison of the creep/duration of load (DOL) performance of a new structural wood composite material called Parallam® parallel strand lumber (PSL) to two grades of machine-stress-rated (HSR) Douglas-fir lumber is presented in this thesis. Evaluation of the creep/DOL performance was made on nominal 2x4 members under constant bending stress at three stress levels. A total of 306 test specimens were evaluated for a 15-1/2 month time period. The analysis suggests that the duration of load effect for Parallam PSL was consistent with the Madison curve for the time period studied while the MSR Douglas-fir lumber was consistent with recent duration of load models developed for structural lumber. The analysis also indicates that the current duration of load adjustment factors can be applied to develop working stresses for Parallam. The creep behaviour of the Parallam PSL was found to be equivalent or better than the two MSR lumber grades under dry-service conditions. Furthermore, evidence of linear viscoelastic behaviour was found for all test materials within the range of applied stresses evaluated. Two mathematical models of creep were fitted to the creep data and compared. A '4-parameter linear viscoelastic' model fitted the creep data better than an empirical 'power curve' model. The model parameters developed provide a basis for estimating the mean creep behaviour and variability in creep response for these materials under in-service load conditions for dry-service environments.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/26194
note: COMPARISON OF CREEP/DURATION OF LOAD PERFORMANCE IN BENDING OF PARALLAM* PARALLEL STRAND LUMBER TO MACHINE STRESS RATED LUMBER by BRUCE A. CRAIG B. Sc. i n Chemical Physics Simon Fraser U n i v e r s i t y , 1976 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n The Department of Forestry We accept t h i s T h e s i s as conforming t o the r e q u i r e d standard. 5/ The University of B r i t i s h Columbia December 1986 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of F o r e s t r y The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date December 16,1986 ABSTRACT A comparison of the creep/duration of load (DOL) performance of a new str u c t u r a l wood composite material c a l l e d Parallam® p a r a l l e l strand lumber (PSL) to two grades of machine-stress-rated (HSR) Douglas-fir lumber i s presented i n t h i s thesis. Evaluation of the creep/DOL performance was made on nominal 2x4 members under constant bending stress at three stress l e v e l s . A t o t a l of 306 test specimens were evaluated for a 15-1/2 month time period. The analysis suggests that the duration of load e f f e c t for Parallam PSL was consistent with the Madison curve for the time period studied while the MSR Douglas-fir lumber was consistent with recent duration of load models developed for structural lumber. The analysis also indicates that the current duration of load adjustment factors can be applied to develop working stresses for Paral…
has type: Thesis/Dissertation
is shown at: 10.14288/1.0096873
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/26194