- 期刊
- OpenAccess
國產柳杉造林木開發結構用集成材之研究
Study of Structural Glulam Manufacturing from Domestic Japanese Cedar Plantation Wood
摘要
本研究針對30年生柳杉造林木開發結構用集成材的可行性，在製造100×304×6150mm中斷面結構用集成材過程中顯示，平均末端直徑200mm之原木鋸製集成元製品之利用率為47.7%，自集成元製造結構用集成材產品之利用率為62.9%，且隨原木直徑之增加可獲得較多集成元數量及較高利用率。柳杉集成元以外觀缺點之目視分等判定品質以3等以下為主，以彈性模數判定則在L60至L90間具有較佳之等級區分效果。以打音法所得之動彈性模數與靜彈性模數判定係數R^2為0.82，且音速與靜彈性模數之R^2為0.71，具有在生產線上推估運用之價值。指接集成元抗彎強度為363kgf cm^(-2)，為無指接材之63.7%。利用較佳之彈性模數值柳杉集成元進行配置組合，可獲得E85-F255及E65-F225等級之對稱異等級集成材。
並列摘要
The feasibility of producing structural glulam (Glued laminated timber) with 30-year-old Japanese cedar (Cryptomeria japonica) plantation wood was investigated in the study. The yield of sawn laminae from logs with on average diameter of 200mm was 47.7%, and the yield for producing medium-sized glulam pieces of 100×304×6150mm from rough sawn laminae was 62.9%. Higher quantities of laminae and higher yields were obtained as the diameter of logs increased from 150 to 300mm. A major grade of no. 3 or lower was obtained as Japanese cedar laminae were visually graded based on wood defects in terms of appearance, while better discrimination among L60~L90 grades was obtained based on the static modulus of elasticity determination. The coefficient of determination, R^2, was 0.82 between the dynamic modulus of elasticity from the tap tone method and static modulus of elasticity for laminae, and R^2 of 0.71 was obtained between the sound velocity and static modulus of the elasticity indicating an advantage of rapid evaluation approach. The bending strength of finger-jointed Japanese cedar laminae was 363kgf cm^(-2), which was 63.7% of that without the finger joints. Balanced structural glulam pieces of E85-F255 and E65-F225 grades were obtained using combinations of laminae with higher elasticities.