螺栓與大木螺釘對柳杉材接合力之評估

Evaluation on Holding Ability of Bolts and Lag Screws with Cryptomeria Lumber

葉民權(Min-Chyuan Yeh) ； 謝俊雄(Chun-Hsiung Hsieh)

《林產工業》 13卷2期 (1994/06) Pp. 263-274

https://doi.org/10.6561/FPI.1994.13(2).4

摘要

本研究在探討柳杉木材以常用於木結構之螺栓及大木螺釘組合時，木材所能承受最大之荷重以及金屬扣件最適之位置。在平行木理受力時，螺栓所能承受之外力隨著直徑的增加而提高，螺栓位置與木材端部之間距離為直徑的1.5至3倍時，其所能承受容許之外力亦隨之提高，間距在4及5倍直徑時，其提高效果不顯著。在垂直木理受力時，隨著螺栓直徑增加，所能承受之外力能力亦提高，同時距離木材邊距2.5倍直徑距離者較邊距1.5倍者能承受更大之荷重，但是就端距而言在直徑5倍以下者彼此間並無差異。在弦向之大木螺釘垂直引拔抵抗亦隨直徑之增加而提高，同時在木材橫斷面之平行木理方向引拔抵抗亦有相同趨勢。大木螺釘在木材橫斷面部位之側向荷重能力較垂直引拔抵抗為弱，可以藉較大直徑之大木螺釘有效地提高接合力。

關鍵字

機械性質 ； 螺桂 ； 大木螺釘 ； 柳杉 ； 林產

並列摘要

The purpose of this study is to find the loading capacity and proper location for fastening Cryptomeria lumber with bolts and lag strews. The loading capacity of bolts in tension along the grain is improved as the end distance increased from 1.5 to 3 times of bolt diameter, and remains the same for the cases of 4 and 5 times of bolt diameter. The improvement of load capacity can also be found by increasing the size of bolt. The loading capacity of bolt in tension perpendicular to the grain increases 20% to 38% as the edge distance increased from 1.5 to 2.5 times of bolt diameter depending upon the size of bolt. However, there are no differences in loading capacity if the bolts are fastened with the end distances under 5 times of bolt diameter and tested in tension perpendicular to the grain. The withdraw resistance of lag screw from tangential face of lumber is improved as the size of lag screw increases. The similar tendency was found for the cases of fastening to the end cross section. The performance in withdraw resistance of lag screw is better than that in lateral resistance on both tangential and cross sectional faces of lumber, and can be improved by applying a larger size of lag screw.

並列關鍵字

Mechanical properties ； bolt ； lag screw ； Cryptomeria