Bending creep of glued laminated timber (glulam) using sugi (Cryptomeria japonica) laminae with extremely low Young's modulus for the inner layers
Bending creep of glued laminated timber (glulam) using sugi (Cryptomeria japonica) laminae with extremely low Young's modulus for the inner layers
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DOI：
10.1007/s10086-011-1175-0
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发表时间：
2011-08-01
影响因子：
2.9
通讯作者：
Arima, Takanori
中科院分区：
文献类型：
--
作者：
Aratake, Shiro;Morita, Hideki;Arima, Takanori
这项研究的主要目的是从长期受载性能的角度，确定日本南部盛产的极低杨氏模数的Sugi木材是否可以实际用作胶合层板(胶合板)的层板。对内层杨氏模数极低(3~4kN/mm(2))的日本柳杉胶合材进行了弯曲蠕变试验，最外层为豆杉杂交材(14~15kN/mm(2))和内层(包括杨氏模数为3~4kN/mm(2)的混交材)进行了弯曲蠕变试验。试件为8根不同成分的胶合木梁，宽105 mm，深210 mm，长3980 mm。蠕变试验期限为4年。研究结果总结如下。其一，L30(杨氏模数为3~4kN/mm(2))与L50(杨氏模数为5~6kN/mm(2))的内层杨氏模量或弯曲蠕变无显著差异。其次，对于非对称组成，在杨氏模量值较低和杨氏模量值较高的情况下，相对蠕变随大气变化而增加和减少的行为表现出相反的行为。第三，蠕变试验估计一条准确的长期曲线所需的试验期限为1或2年(不包括前6个月的数据)，此时采用幂定律进行估计。第四，由试验得到的50年相对蠕变值远低于日本建设省第1459号通知所规定的标准值2，且这些值不受板层成分的影响。
The main purpose of this study was to establish whether sugi lumber with an extremely low Young's modulus, which is plentifully produced in southern Japan, can be practically used as laminae for glued laminated timber (glulam) from the viewpoint of long-term performance under loading. Bending creep tests were carried out on sugi (Cryptomeria japonica D. Don) glulam with extremely low Young's modulus laminae (3-4 kN/mm(2)) for the inner layers, as were tests on hybrid glulam with Douglas-fir (Pseudotsuga menziesii Franco) laminae (14-15 kN/mm(2)) for the outermost layer and sugi laminae (including those with a Young's modulus of 3-4 kN/mm(2)) for the inner layers. The specimens were eight glulam beams with different compositions that were 105 mm wide, 210 mm deep, and 3980 mm long. The term of the creep test was 4 years. The results are summarized as follows. First, there were no significant differences between the Young's modulus or bending creep of glulam L30 (laminae with Young's modulus of 3-4 kN/mm(2)) and that of glulam L50 (laminae with Young's modulus of 5-6 kN/mm(2)) for the inner layers. Second, for asymmetric compositions, the behavior of increases and decreases of relative creep due to atmospheric changes showed opposite behavior for glulam loaded from the side of lower Young's modulus and from the side of higher Young's modulus. Third, the required experimental term for the creep test to estimate an accurate long-term curve is 1 or 2 years (with data for the first 6 months excluded) when the power law is used for the estimation. Fourth, the values of relative creep in 50 years obtained from the experimental term were much lower than 2, which is the standard value set by Notification No. 1459 of the Ministry of Construction in Japan, and these values were not affected by the composition of the laminae.