Size Effects in Visually Graded Softwood Structural Lumber

Barrett, J. D.; Lam, Frank; Lau, W.

doi:10.1061/(asce)0899-1561(1995)7:1(19)

Cited by 38 publications

(20 citation statements)

References 5 publications

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“…Madsen (1990) reported a size adjustment factor according to depth of 0.25 for the defect-free wood member not in structural lumber. Barrett et al (1995) showed that the size factor for bending was in the range of 0.14∼0.26 and this study's result was in general agreement with their range and that published in the literature, as shown in Table 5. Therefore, the present study result of decreasing lumber strength with increasing member depth was considered consistent evidence for the depth effect in bending of domestic structural lumber.…”

Section: Resultssupporting

confidence: 82%

“…Size effect of bending strength for wood members was studied extensively by several researchers (Bohannan, 1966;Johnson et al, 1989;Madsen, 1990;Barrett and Lau, 1994;Barrett et al, 1995). Test results revealed that strength of wood was influenced by size of members, and size effect based on strength data might be considered in timber design.…”

Section: Introduction 1)mentioning

confidence: 99%

“…The structural properties of lumber have been studied extensively over the last several decades in order to develop the materials property information required for assessing the reliability of timber structures and developing a reliabilitybased timber design code (Barrett et al, 1995). Strength properties of wood are derived initially for small, clear, defect-free wood and then allowances are made for the strength reduction defects such as knots, slope of grain, checks and splits.…”

Section: Introduction 1)mentioning

confidence: 99%

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Estimation of Depth Effect on the Bending Strength of Domestic Japanese Larch Structural Lumber using Weibull Weakest Link Theory

Oh¹

2014

Journal of the Korean Wood Science and Technology

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The depth effect on bending strength of Japanese larch structural lumber was investigated by using the published data of two different depth lumbers with the same length. Depth effect parameters were derived from Weibull's weakest link theory and compared to the results from other researches. Depth effect on bending strength was significant for No.1 and No.3 lumber, but not insignificant for No.2 lumber. Calculated value of the depth effect adjustment factors was 0.21, 0.11 and 0.22 by lumber grade, respectively. These results were similar to those results from previous researches and supported depth effect on bending strength of lumber. An apparent depth adjustment factor has been proposed to 0.2 in the literatures. Based on this study, depth adjustment factor was considered to 0.2 as a conservative optimum design value that should be incorporated in domestic building code (KBC) for structural lumber.

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Section: Resultssupporting

confidence: 82%

Section: Introduction 1)mentioning

confidence: 99%

Section: Introduction 1)mentioning

confidence: 99%

See 1 more Smart Citation

Estimation of Depth Effect on the Bending Strength of Domestic Japanese Larch Structural Lumber using Weibull Weakest Link Theory

Oh¹

2014

Journal of the Korean Wood Science and Technology

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“…Small-scale comparisons for a limited number of specimens were carried out by Almazán et al (2008) for German pine graded by DIN 4074 and UNE 56544 or by Riberholt (2008) for European spruce graded according to Chinese visual rules. Visual grading is addressed in several available CIB-W18 timber structures publications (Fewell 1984;Uzielli 1986;Barrett et al 1992;Stapel et al 2010), but none of these focused on the comparison of different grading rules and the assignment according to EN 1912. Verification of the validity of grading standards for such large growth areas as CNE is the main goal of the present article. Softwoods (spruce, pine, larch, Douglas fir, and Sitka spruce) will be graded and tested in tension or by edgewise bending.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of visual strength grading of timber with respect to origin, species, cross section, and grading rules: a critical evaluation of the common standards

Stapel

Kuilen²

2013

Holzforschung

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Strength grading is essential for the efficient use of structural timber. Although international standards exist for machine strength grading, visual grading is still regulated based on national rules, which are expected to allow safe and economic grading results. Although there are large differences in the graded output because the species, the cross section, and the origin of the timber influence the results, some of these standards are considered to be applicable universally. The present article demonstrates how the chosen standards influence the grading results. Depending on the parameters, the yields or the mechanical properties are low compared with the declared values. The results also show the efficiency and applicability of different national standards for strength grading of timber from various origins. Furthermore, it is recommended to reconsider the existing limits for source areas and cross sections given in the standard EN 1912.

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“…During testing, the instantaneous tensile load along the length of the test specimen is considered constant. Madsen (1992) and Barrett et al (1995) provided comprehensive reviews of length effect studies on the tensile strength of lumber. Past experimental studies (Lam and Varoglu 1990, Madsen 1990, Showalter et al 1987) demonstrated that tensile strength of lumber was member length dependent.…”

Section: Introductionmentioning

confidence: 99%

Length effect on the tensile strength of truss chord members

Lam¹

2000

Can. J. Civ. Eng.

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Length effects on the tensile strength of multiple member truss chords have been studied. Simulation and reliability studies have been presented to evaluate the impact of length and multiple member effects on the target safety index for tensile failure. Results indicate significant length effect can be expected for long multiple tension chord members. Based on the Weibull weakest link theory, length effect adjustment parameters have been established. Further simulation and reliability studies have demonstrated the robustness of the proposed length effect adjustment procedures. A procedure has been developed for the design of truss chord members considering Weibull weakest link based size effect and non-uniform loading along the length of bottom chord truss members such that the target reliability index can be maintained.

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Size Effects in Visually Graded Softwood Structural Lumber

Cited by 38 publications

References 5 publications

Estimation of Depth Effect on the Bending Strength of Domestic Japanese Larch Structural Lumber using Weibull Weakest Link Theory

Estimation of Depth Effect on the Bending Strength of Domestic Japanese Larch Structural Lumber using Weibull Weakest Link Theory

Efficiency of visual strength grading of timber with respect to origin, species, cross section, and grading rules: a critical evaluation of the common standards

Length effect on the tensile strength of truss chord members

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