Moment-Resisting Capacity of Bolt Connections in Japanese Cedar Structural Glulam Members

結構用柳杉集成材之螺栓接合抗彎矩強度研究

葉民權(Min-Chyuan Yeh) ； 吳康正(Kang-Cheng Wu) ； 林玉麗(Yu-Li Lin)

《台灣林業科學》 23卷4期 (2008/12) Pp. 365-375

https://doi.org/10.7075/TJFS.200812.0365

摘要

本研究採用國產柳杉造林木開發結構用集成材，探討大尺寸木質構材以螺栓扣件組合之接合性能。以螺栓貫穿金屬扣件將柱及梁構材接合成T型構件，利用彎曲強度試驗機進行實大尺寸彎矩試驗。結果顯示，以各構材分別使用6支直徑15 mm螺栓接合之試驗條件其彎矩破壞載重最高，平約為18.42kN-m，而使用4支直徑15 mm螺栓條件者較低，平約為11 kN-m，同時發現使用螺栓支數對於接合性質之影響遠大於螺栓直徑之影響。進一步顯示螺栓直徑在15 mm及18 mm的條件下，使用6支螺栓之構材接合破壞彎矩分別比4支螺栓接合者明顯提高67.4及53.0%；旋轉係數改善195及97.6%；接合效率提高66.7及55.6%；剛性效率則提高65.3及21.0%。利用ANSYS有限元素分析軟體模擬試材在最大載重之30%範圍下，其應力以及螺栓孔周邊應變分布情形，結果顯示分析主要之抗壓應力位置與實際破壞位置相符，而螺栓孔周邊之應變值在梁構材中性軸上方主要產生拉伸應變，在下端處主要產生壓縮應變。

關鍵字

集成材 ； 接合強度 ； 有限元素分析 ； 金屬扣件

並列摘要

Domestic plantation timber of Japanese cedar (Cryptomeria japonica) was used to develop structural glulam members, and the joint strength of full-scale glulam members with bolts was investigated in this study. The post and beam glulam members were joined into a T-type structure by a steel plate and bolts with nominal diameters of 15 and 18 mm, and each member was fastened with 4 or 6 bolts. Full-scale moment-resisting tests were performed using a flexural testing machineto evaluate the properties of the joints, and the effects on joint strength among the different test conditions. The results indicated that the joint with 6 15-mm bolts had the highest bending moment capacity, with an average of 18.42 kN-m, and the lowest was the joint with 4 15-mm bolts, with an average of 11.0 kN-m. In general, the effect of bolt numbers on the joint strength was more significant than that of bolt sizes. The moment-resisting capacities of glulam assembled with 6 15- and 18-mm bolts were 67.4 and 53.0% higher than that of 4 bolts, respectively, and coefficients of rotation improved 195 and 97.6%, jointing efficiencies increased 66.7 and 55.6%, and rigid efficiencies increased 65.3 and 21.0%. The simulated stress distribution of the specimen at the level of 30% of the ultimate load, and the strain distribution around the bolt holes were obtained by a finite element method using ANSYS software in this study. The results showed that the locations of major estimated compressive stresses closely matched the actual failure locations on the glulam joints, and strain values around the bolt holes mainly showed tension strain on the upper side of the neutral axis of the beam member, and compressive strains on the bottom side.

並列關鍵字

glulam ； joint strength ； finite element analysis ； mechanical fastener