Some aspects of load duration behaviour in wood
Present design stresses for structural timber include a reduction factor to account for the duration of loading. Recent studies have shown however that this factor does not apply to commercial grade timber containing knots and other irregularities of grain. It has also been shown that the apparent...
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ndltd-UBC-oai-circle.library.ubc.ca-2429-193642018-01-05T17:39:55Z Some aspects of load duration behaviour in wood Clark, Kenneth Bruce Present design stresses for structural timber include a reduction factor to account for the duration of loading. Recent studies have shown however that this factor does not apply to commercial grade timber containing knots and other irregularities of grain. It has also been shown that the apparent Young's modulus perpendicular to grain in clear material decreases greatly with longer durations of loading. It was therefore hypothesized that in commercial grade wood, stress concentrations are made less severe in long term loadings because of stress redistribution, made possible by straining perpendicular to grain. This thesis found experimentally that the amount of tensile straining perpendicular to grain around a knot in timber beams subjected to bending increased substantially with long duration loadings. In conjunction with this, a computer simulation of the material around a knot showed that a decreasing apparent Young's modulus perpendicular to grain reduces the stresses perpendicular to grain. Applied Science, Faculty of Civil Engineering, Department of Graduate 2010-01-29T20:42:48Z 2010-01-29T20:42:48Z 1975 Text Thesis/Dissertation http://hdl.handle.net/2429/19364 eng 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. |
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English |
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description |
Present design stresses for structural timber include a reduction factor to account for the duration of loading. Recent studies have shown however that this factor does not apply to commercial grade timber containing
knots and other irregularities of grain. It has also been shown that the apparent Young's modulus perpendicular to grain in clear material decreases greatly with longer durations of loading. It was therefore hypothesized that in commercial grade wood, stress concentrations are made less severe in long term loadings because of stress redistribution, made possible by straining perpendicular to grain.
This thesis found experimentally that the amount of tensile straining perpendicular to grain around a knot in timber beams subjected to bending increased substantially with long duration loadings. In conjunction with this, a computer simulation of the material around a knot showed that a decreasing apparent Young's modulus perpendicular to grain reduces the stresses perpendicular to grain. === Applied Science, Faculty of === Civil Engineering, Department of === Graduate |
author |
Clark, Kenneth Bruce |
spellingShingle |
Clark, Kenneth Bruce Some aspects of load duration behaviour in wood |
author_facet |
Clark, Kenneth Bruce |
author_sort |
Clark, Kenneth Bruce |
title |
Some aspects of load duration behaviour in wood |
title_short |
Some aspects of load duration behaviour in wood |
title_full |
Some aspects of load duration behaviour in wood |
title_fullStr |
Some aspects of load duration behaviour in wood |
title_full_unstemmed |
Some aspects of load duration behaviour in wood |
title_sort |
some aspects of load duration behaviour in wood |
publishDate |
2010 |
url |
http://hdl.handle.net/2429/19364 |
work_keys_str_mv |
AT clarkkennethbruce someaspectsofloaddurationbehaviourinwood |
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1718591107286171648 |