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Visual stress grading of timber pdf
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SS, GS (softwoods to BS) Assign to strength class based on grading standard, species and origin (all three must match) Stress Grading is a way of classifying timber, either visually or by mechanical means to indicate the basic properties to be used for structural design purposes. The stress Timber—Hardwood—Visually stress-graded for structural purposes SECTIONSCOPE AND GENERAL SCOPE This Standard specifies requirements for visually stress The National Grading Rule establishes the lumber classifica-tions and grade names for visually stress-graded dimension lumber (Table 6–2) and also provides for the grading of dimension lumber by a combination of machine and visual methods The general principle of this document is that any type of visual strength-grading procedure is acceptable, provided it is defined, controlled, and documented to the extent required to reflect the degree of certainty of structural properties intended for the structural application of the product From one to six design properties are associated with a stress grade: bending modulus of elasticity for an edgewise loading orientation, stress in tension and compression parallel to the grain, stress in compression perpendicular to the grain, stress in shear parallel to the grain, and extreme fiber stress in bending Like lumber, the Allowable Unit Stress (AUS) value for the species of wood and the grade is based on clear wood values adjusted for duration of load, natural variability, and a factor of safety which reduces the lower 5% level of the mean of that species’ clear wood strength Historically, both visual strength-grading and NDT techniques have been developed and used almost exclusively for sorting or grading new timber in the sawmill. Three grades are spe cified, LA, LB and Visual strength grading Visually grade –e.g. Hardwood? Both approaches, however, can be adopted to provide information pertaining to the load-bearing capability of timber in place in a structure Stress visual grading of wood is provided in BS this standard also sets out the requirements for laminated timber ('glulam'). Visually stress-graded for structural purposes [20] Australian/New Zealand Standard AS/NZS, Timber? Australian Standard AS, Timber?
Rating: 4.9 / 5 (4908 votes)
Downloads: 38670
CLICK HERE TO DOWNLOAD
SS, GS (softwoods to BS) Assign to strength class based on grading standard, species and origin (all three must match) Stress Grading is a way of classifying timber, either visually or by mechanical means to indicate the basic properties to be used for structural design purposes. The stress Timber—Hardwood—Visually stress-graded for structural purposes SECTIONSCOPE AND GENERAL SCOPE This Standard specifies requirements for visually stress The National Grading Rule establishes the lumber classifica-tions and grade names for visually stress-graded dimension lumber (Table 6–2) and also provides for the grading of dimension lumber by a combination of machine and visual methods The general principle of this document is that any type of visual strength-grading procedure is acceptable, provided it is defined, controlled, and documented to the extent required to reflect the degree of certainty of structural properties intended for the structural application of the product From one to six design properties are associated with a stress grade: bending modulus of elasticity for an edgewise loading orientation, stress in tension and compression parallel to the grain, stress in compression perpendicular to the grain, stress in shear parallel to the grain, and extreme fiber stress in bending Like lumber, the Allowable Unit Stress (AUS) value for the species of wood and the grade is based on clear wood values adjusted for duration of load, natural variability, and a factor of safety which reduces the lower 5% level of the mean of that species’ clear wood strength Historically, both visual strength-grading and NDT techniques have been developed and used almost exclusively for sorting or grading new timber in the sawmill. Three grades are spe cified, LA, LB and Visual strength grading Visually grade –e.g. Hardwood? Both approaches, however, can be adopted to provide information pertaining to the load-bearing capability of timber in place in a structure Stress visual grading of wood is provided in BS this standard also sets out the requirements for laminated timber ('glulam'). Visually stress-graded for structural purposes [20] Australian/New Zealand Standard AS/NZS, Timber? Australian Standard AS, Timber?