臺灣博碩士論文加值系統

本研究主要探討自攻螺絲補強木構造接點的剪力行為，透過剪力試驗及相關的補充性試驗，觀察緊固件能夠提供的剪力強度、延展性及整體構件的破壞型態，並以實驗結果和歐盟木構造設計規範中接點之剪力公式計算的剪力值進行比較，以評估歐盟規範公式應用於台灣常用之材種及自攻螺絲的可行性。

剪力試驗之試體配置是以三支結構用之木材透過結構用自攻螺絲進行組合，在中間主構材施予載重，形成雙剪切面的受力形式。藉由文獻回顧整理，可知影響接點剪力力學行為的相關因子，以規劃實驗參數。本研究是以木構件的材種(福杉及柳杉)、緊固件的種類(全牙及半牙自攻螺絲)及有無使用墊片的鎖固作為剪力試驗的實驗參數，以了解材種、接合形式對於接點力學行為之影響。之後以20噸萬能試驗機進行加載，以3mm/min的加載速度進行，並加載至試體破壞為止，過程中紀錄載重、位移的關係，並觀察構件破壞的型態。

經由剪力試驗所得之實驗結果可知，在材種方面，雖然使用福杉的試體在最大承載能力及剛度方面皆不及柳杉，但是在穩定性及韌性方面卻比柳杉優異。就破壞類型而言，使用福杉的試體以木構件外觀上無顯著破壞的破壞類型為主，其發生率為69%，而柳杉則以外觀上有脆性破壞為主要的破壞類型，其發生率為86%。而在緊固件對於剪力行為的影響方面，由實驗結果顯示，雖然使用全牙自攻螺絲各方面力學性能的整體平均皆大於使用半牙之試體，但其差異並不顯著。而在破壞類型方面，使用全牙自攻螺絲以外觀無顯著破壞且線形長的破壞類型為主，其發生率為53%；而使用半牙自攻螺絲以外觀有脆性破壞的破壞類型為主，其發生率為69%。
而在接點有無使用墊片對於剪力行為的影響，由實驗結果得知，儘管有使用墊片試體的剛度略小，但是在韌性及最大承載能力方面卻具有比無使用墊片試體更可觀的延展性及承載能力。而在破壞類型方面，有無使用墊片對於外觀上有無顯著的破壞影響不大。

最後由歐盟接點評估公式的計算結果可知，模態一公式(h)的計算值代表剪力強度的理論值，其中，使用柳杉試體的剪力強度理論值為10334.40 N，福杉為8438.40 N。計算值與實驗值誤差範圍為16%至51%之間，且實際測得之實驗值大於理論值，評估結果相對保守；若需要更精準地評估預測接點的剪力強度及破壞模式，則建議進一步修正、優化評估公式，以利國產材的力學性能評估。

This study mainly explored the shear behaviour of self-tapping screws intended for reinforcing timber structural joints. Shear tests and relevant supplementary tests were conducted to measure the shear strength and ductility of fasteners as well as the failure mode of the entire components. The species of the structural Chinese fir (Cunninghamia lanceolata) and Japanese cedar (Cryptomeria japonica), types of fastener (fully-threaded or half-threaded self-tapping screw), and use of washers served as the experimental parameters of shear tests for examining the effects of timber species and joints’ profiles. The shear test is carried out by 20-ton universal testing machine. The experimental results were compared to the shear values calculated based on European Union (EU) timber structure design code in order to evaluate the feasibility about applying the equation for predicting timber joints with self-tapping screws as dowel type fasteners in Taiwan. According to the results of the shear tests, the maximum capacity and rigidity were significantly affected by the physical properties of materials, particularly wood. While the species of wood dominate the ultimate shear strength, the washers influence the failure mode. Regarding the effect of fasteners on shear behaviour, however, no significant difference was observed in the effect of fully-threaded or half-threaded self-tapping screws within the joints. Calculation results based on EuroCode 5, Equation 8.7 revealed that the (h) value represented the theoretical shear strength. The analytic values and experimental results exhibited a discrepancy between 16% and 51% for eight specimens. The testing results were greater than the theoretical values, suggesting relatively conservative estimation consequences. With regard to the failure mode, however, the accuracy of prediction is insufficient and the equations might require further modification for Taiwanese wood.

摘要………………………………………………………………………………………….I
目錄…………………………………………………………………………………….....VIII
圖目錄……………………………………………………………………………………... X
表目錄………………………………………………………………………………….... XIII
照片目錄…………………………………………………………………………….……XV
符號表……………………………………………………………………………….…XVII
第1章 緒論………………………………………………………………………………..1
1-1研究動機……………………………………………………………………………..1
1-2研究目的……………………………………………………………………………..3
1-3研究方法……………………………………………………………………………..4
1-4研究流程……………………………………………………………………………..6
第2章 文獻回顧…………………………………………………………………………..7
2-1複合構造及其剪力機制……………………………………………………………..7
2-2剪力緊固件之力學行為……………………………………………………………12
2-3歐盟木構造設計規範之評估公式…………………………………………………16
第3章 試驗規劃…………………………………………………………………………19
3-1剪力試驗……………………………………………………………………………19
3-1-1試體規劃………………………………………………………………………19
3-1-2實驗架設計……………………………………………………………………25
3-2自攻螺絲抗拉拔試驗………………………………………………………………27
3-2-1試體規劃………………………………………………………………………27
3-2-2實驗架設計……………………………………………………………………30
3-3自攻螺絲抗彎試驗…………………………………………………………………32
3-3-1試體規劃與實驗架設計………………………………………………………32
第4章 試驗結果與討論…………………………………………………………………35
4-1試驗結果……………………………………………………………………………35
4-1-1材種對剪力行為的影響………………………………………………………38
4-1-2緊固件種類對剪力行為的影響………………………………………………40
4-1-3有無使用墊片對剪力行為的影響……………………………………………42
4-2破壞類型……………………………………………………………………………43
4-2-1材種對破壞類型的影響………………………………………………………44
4-2-2緊固件種類對破壞類型的影響………………………………………………46
4-2-3有無使用墊片對破壞類型的影響……………………………………………48
4-3歐盟公式驗證………………………………………………………………………49
4-3-1歐盟接點評估公式的計算……………………………………………………49
4-3-2歐盟接點評估公式的計算值與實驗值對照…………………………………51
4-4討論…………………………………………………………………………………52
第5章 結論與建議………………………………………………………………………58
5-1 結論………………………………………………………………………………...58
5-2後續研究建議………………………………………………………………………59
參考文獻…………………………………………………………………………………..61
附錄A 剪力試驗…………………………………………………………………………63
附錄B自攻螺絲抗拉拔試驗…………………………………………………………...135
附錄C自攻螺絲抗彎試驗……………………………………………………………...145
附錄D木材抗壓試驗…………………………………………………………………...150

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