Studies on improving mechanical properties and effective application for beams of flat squares obtained from lower part of sugi logs

(1)对杉木大径材锯条的力学性能进行了测试。结果表明，圆锥尺锯切一次原木去髓木材与中心尺锯二次原木去髓木材的性能基本相同。(2)为明确曲线材Sugi锯材的性质，进行了一些评价试验。结果表明，对于最大弯曲率在1%~2%左右的原木(即所谓的“B在”)，在考虑锯干翘曲、弯曲强度和蠕变变形的情况下，对于梁来说，几乎没有什么实用的障碍来挑选它们。

(1) Mechanical properties of flat squares sawn from sugi large diameter logs were examined. As a result, it was clarified that the lumber without pith sawn from first logs by taper rule sawing has almost the same properties as lumber with pith sawn from second logs by center rule sawing. (2) In order to clarify the properties of sugi sawn lumber obtained from curved logs, some evaluation tests were carried out. The result showed that, as far as the logs with maximum curved rate of about 1-2% go (so-called “B-zai”), there is almost no practical barrier to pick out them for beams considering the warp due to sawing and drying, bending strength, and creep deflections.