Manufacturing Techniques of Structural Glulam by Using Domestic Japanese Fir

• Main Authors: Wen-Shyong Lee, 李文雄
• Other Authors: Min-Chyuan Yeh
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/02722301604322512616

碩士 === 國立屏東科技大學 === 森林系 === 92 === The development of manufacturing techniques of structural glued laminated timber and evaluation on flexural properties with actual sizes of 615 cm by 10 cm by 30.4 cm were done by using domestic Japanese fir plantation in the study. The logs of 30 years old were sawn into laminae products. The yield of 47.5 % from logs was obtained for sawn lumber products. The yield of swan lumber reduced 4.7 % after kiln drying process. And yield of Japanese fir lumber from laminae to structural glulam products was 62.9 %. Based on defect characteristics grading rules specified in CNS structural glulam standard, most Japanese fir laminae conformed to grade #3 only and accounted for 59.5 %. There was 39 % of laminae qualified with L90 based on nondestructively flexural testing method, and 11% of laminae as L80, 20 % of laminae as L70, and 30 % of laminae below the grade of L70. The results from the longitudinal vibration method showed a significant positive relationship between modulus of elasticity and dynamic modulus of elasticity, i.e., R2 is 0.82. Sound velocity also have significant positive relationship with both of modulus of elasticity and dynamic modulus of elasticity, i.e., R2 are 0.71 and 0.83, respectively. The performance of finger joint and the gluing operation are the critical factors during the manufacturing of structural glulam. The finger joint efficiency of laminated Japanese fir member is 63.7 %. The splitting failure from finger joint of the flexurally tested Japanese fir laminae had the highest percentage of 69.6 %. The results indicated that no significant difference on modulus of rupture among four types of uniformly laminated glulam member, and the flexural properties did not conform to the grade of E65-F255. But the flexural properties of balanced symmetrical laminated member type 1 and type 2 were conformed to the grade of E85-F255 and E65-F225, respectively. The failure of splitting from finger joint for the flexurally tested Japanese fir glulam accounted 74.1 %. While failure occurred at the tension side laminae with defects is accounted for 14.8 % and the delamination between laminae is 11.1 %. The materials of Japanese fir laminae is accounted 77 % of cost estimation for structural glulam manufacturing. Based on this study, the production cost of a glulam beam is NTD7,462. It is suggested that if we want to control the process cost of Japanese fir glulam manufacturing, the quality control shall start from processing the logs to achieve the target of low cost and high quality, and gain the competition in the market.