不同标准体系中结构用规格材目测分级规则的比较

分析比较了我国GB 50005—2003《木结构设计规范》、北美规格材目测分等规则NLGA(2003)、英国针叶材强度目测分级规则BS 4978—2007、国际结构用规格材强度目测分级ISO 9709(2005)和澳大利亚结构用针叶材锯材目测分等标准AS 2858—2008等5种标准的异同。结果表明：中国与北美分等标准基本相同，不同之处是中国分等标准采用国际单位，而北美分等标准采用英制单位；英国与国际分等标准基本相近，结构用规格材都分为两个等级，不同之处为国际分等标准中提出非结构用规格材强度特征值的限定；澳大利亚分等标准中通过密度区分结构用材和非结构用材，并且在对钝棱、轮裂和生长轮平均宽度的计算及界定时，均与其他4种标准不同。此外，笔者提出了对我国结构用规格材目测分等规则的修改建议。

Comparison of visual grading rules for structural lumber in different standards

The difference of visual grading rules on dimension lumber among the Chinese standard GB 50005-2003, North American standard NLGA(2003), British standard BS 4978-2007, International standard ISO 9709 (2005 ) and Australian standard AS 2858-2008 were analyzed. The results showed that there was the same visual grading rule on dimension lumber between Chinese standard and North American standard, the only difference was that international unit was used to Chinese standard, and the British unit was used to North America standard; The British standard and the international standard was similar to the structure dimension lumber with specifications are divided into two grades. The difference was that the strength characteristics of non-structural lumber of international standard was limited. The dimension lumber of Australian standard through the density was graded structural lumber and non-structural lumber. Australian standard on measuring wane, shake and the average width of growth ring was difference from the other four standards. Based on the results , some of suggestions were proposed to revise the Chinese visual grading rules for structural lumber.