Evaluation of the Tensile Strength of Structural Finger-Jointed Lumber

結構用指接材之抗拉強度評估

葉民權(Min-Chyuan Yeh) ； 林玉麗(Yu-Li Lin) ； 黃永欽(Yung-Chin Huang)

《台灣林業科學》 26卷1期 (2011/03) Pp. 59-70

https://doi.org/10.7075/TJFS.201103.0059

摘要

本研究針對5種針葉材集成元以3種不同指榫長度及分別以垂直或水平方向指接後進行抗拉強度性能評估。結果顯示花旗松指接材之指接接合效率最高為74.1%，其次為雲杉－松－冷杉指接材65%。柳杉及南方松指接材由於指榫弱，在拉伸力下形成斷裂破壞而具較低之接合效率。在指接材之抗拉強度方面，南方松為最佳，優於最弱之柳杉116.6%，花旗松亦高於柳杉65.9%。鐵杉及雲杉－松－冷杉指接材有相近之抗拉強度，分別優於柳杉46.8及40.7%。指榫長21mm之指接材由於受到較大之指端寬之影響，其抗拉強度分別低於18及24mm指榫長之指接材11.3及8.5%。結果顯示指榫以水平成型組合與垂直成型組合之指接材的抗拉強度間並無差異，但除了指榫長21mm條件之外，18及24mm指榫接合條件下，垂直成型組合之指接材抗拉強度高於水平成型組合者7.4%。

關鍵字

指接 ； 集成材 ； 抗拉強度 ； 柳杉

並列摘要

A study was undertaken to evaluate the tensile strength performance of both vertically and horizontally finger-jointed laminae with 3 different lengths of finger profiles for 5 softwood species. Douglas fir finger-jointed lumber showed the best joint efficiency at 74.1%, followed by spruce-pine-fir (SPF) groups, at 65%, among the 5 wood species. Both Japanese cedar and southern pine finger-jointed lumber had lower joint efficiencies due to weak finger profiles causing early failure in tension. Southern pine finger-jointed lumber was found to have the highest tensile strength, 116.6% higher than the lowest Japanese cedar group, followed by the Douglas fir group which was 65.9% higher. The hemlock and SPF groups had similar tensile strengths, and they were also higher than the Japanese cedar group by 46.8 and 40.7%, respectively. The tensile strength of lumber joined with a 21-mm long finger profile showed a significantly lower value than those with 18- and 24-mm finger profile groups by 11.3 and 8.5%, respectively, due to the wide finger tips. The results show that there was no significant difference in tensile strength of finger-jointed lumber between horizontal and vertical finger formation. With the exception of the 21-mm finger-jointed group, slightly higher tensile strength (7.4%) for the 18- and 24-mm finger length groups with vertical finger-joints was obtained, compared to those with horizontal joints.

並列關鍵字

finger joint ； glulam ； tensile strength ； Japanese cedar