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題 名 | 進口南洋材之結構材容許應力設計值建立之探討=Investigation on Establishing Allowable Strength Properties for Structural Lumber Imported from Southeast Asia |
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作 者 | 葉民權; | 書刊名 | 林產工業 |
卷 期 | 17:1 1998.03[民87.03] |
頁 次 | 頁37-58 |
分類號 | 436.187 |
關鍵詞 | 容許應力; 分等; 木材機械性質; Allowable stress; Grades; Mechanical properties of wood; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究之目的在發展一套進口主要南洋材之結構用木材容許應力設計值,期能拓展 種類豐富的南洋材在木結構的應用,並與現行設計規範作一比較。研究中係依樹木分類及統計 聚類分析將樹種合併,再依據ASTM標準中所規範結構用材之容許應力建立程序作為主體架構, 利用標準試材之機械性質數值,經過適當之分等及各項修正因子的調整,以電腦計算而得各類 木材的容許應力設計值。本研究將五十一類主要南洋材依強度歸納為七大類,每大類再區分為 結構輕框架、結構托樑與板材、樑與縱桁、柱與角材等四種用途別,各用途別又區分為一等材 與二等材。所建議之無缺點木材強度值,以巴杜類、甘不-鐵木類、冰片樹-阿匹棟類、及拉敏 -花梨木類較優,而橡膠木類次之,再其次為柳桉類,而南洋桐-臭酸仔類最差。最後各項應力設 計值調降幅度以二等材較大,其中以靜曲強度與剪斷強度調降最大,平行木理壓縮強度次之, 彈性係數為最小。與現行設計規範比較時,所推導之靜曲應力值較能依結構材用途別顯示應力 值的差異,而平行木理壓縮應力及拉伸應力設計值則較現行之闊II類及III類木材為低。所 推導之彈性係數設計值以巴杜類、冰片樹-阿匹凍類為最優,南洋桐-臭酸仔類為最低。所推導 的剪斷強度設計值各樹種類別均介於現行油仔與柳桉二級材之間,故合理之分類應具有適材 適用的效果。而所推導之垂直木理壓縮強度設計值則較現行規範者高,同時也能顯示不同樹種 類別之強度差異,在木材利用上較具彈性且較為合理。 |
英文摘要 | The purpose of this study is to develop an allowable design properties system for structural lumber of species imported from southeast Asia. The establishing procedures for allowable stress are mainly according to ASTM Standards. There are seven groups of species combination established, which are based on the results of cluster analysis and marketing demand. The clear wood strength were assigned to each species combination based on mechanical properties data from standard testing specimens. Each species combination is then divided into four types of usage: structural light framing, structural joist and plank, beams and stringers, post and timber, Each type was in turn classified into No.1 and No.2 grades. It is noted that Batu, Kempas-Ipil, Kapur-Apitong, and Ramin-Padauk groups show higher allowable stress design values, while Rubber Wood group shows lower design values and Jelutong-Binuang group is the weakest in design properties. The derived design values for static bending and shear strength show the greatest reduction from the clear wood strength, following by compression strength, while modulus of elasticity design values has the least reduction. As compared to current specification, the derived allowable bending stress design values can be more flexible according to usage classification of lumber. On the other hand, both the derived allowable compressive and tensile stress are lower than corresponding design values for type II and III type species in the current specification. The derived allowable shear stress design values, which varies between listed values for Keruing and Lauan groups in current specification, indicate that better utilization of lumber can be achieved by reasonable classification. The allowable compressive stress perpendicular to grain are higher than the corresponding values listed in the current specification, and are different among species combination. |
本系統中英文摘要資訊取自各篇刊載內容。