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Feasibility Study of Steel Fibers as a Substitute for Transverse Reinforcement in New RC Columns
No full text國內的建築物中，鋼筋混凝土結構(Reinforced Concrete, RC)佔了絕大多數，主要因為RC結構有下列優點：耐久性佳、易維護，與成本低。隨著時代的演進，高樓層建築是現今的趨勢。隨著樓層的提高，位於底層的柱需承受整體結構物荷重產生的高軸力，若用傳統的RC結構，勢必得放大低樓層柱的斷面。因此日本在1988年推出為期5年的New RC Project，以提高材料強度的方法，減少材料的用量，使得結構物輕量化。高強度材料的RC結構，不僅可以降低柱斷面的尺寸、減量材料的用量與成本，也提升建築物的使用空間。
然而高強度的材料的脆性行為是其隱憂，由於高強度混凝土開裂時，裂縫會直接通過粗骨材與砂漿，因此一旦到達極限強度，結構物會立即破壞，造成嚴重的損害。除此之外，台灣位處地震發生頻繁之地震帶，結構物必須具有一定的韌性，越高的韌性越能折減地震力。為了提高結構物韌性表現，在傳統RC結構中添加新材料便是方法之一。根據文獻顯示，鋼纖維能提高混凝土材料的韌性以及剪力抗性，減少橫向箍筋量的需求，降低鋼筋籠綁紮的繁瑣。而且纖維不僅能預防早期保護層剝落，抑制裂縫生長，並會在其他部份產生多重裂縫，避免瞬間破壞的發生。
本研究主要探討在雙曲率反覆側推行為下，高強度鋼纖維鋼筋混凝土柱的行為表現，並與高強度鋼筋混凝土柱進行比較。主要分為兩大主軸，其一為「高強度混凝土與高強度鋼纖維混凝土比較」，探討相同混凝土設計強度下，一般混凝土與鋼纖維混凝土的行為差異。其二為「以鋼纖維取代橫向箍筋之評估」，以放大箍筋間距的方式，探討鋼纖維與橫向箍筋的取代關係，間距最大到規範訂定剪力鋼筋間距最嚴苛的標準，也就是一半的斷面深度。另外針對鋼筋混凝土柱以及鋼纖維鋼筋混凝土柱之韌性指數進行回歸，提出預測公式。並且根據預測公式建立圍束效應與反覆側推行為之關係式，未來具備試體設計斷面，便可以此關係式判斷反覆側推實驗結果能否通過側力衰減至80%時，層間變位角達到3%之標準。There are several advantages of reinforced concrete. For example, reinforced concrete is durable. Also, the buildings built by reinforced concrete are easy to conserve and maintain the structure. Moreover, the cost is low to build the buildings with reinforced concrete. It is a trend that people start to build high-rise buildings. The higher the building is, the more axial load of the columns at the bottom sustain. If the high- rise buildings are built with the traditional RC structure, the lower floors’ dimension must be enlarged. Therefore, in 1988, New RC project was proposed in Japan. The purposes of the project were increasing the strength of the construction materials and reducing the amount of the materials. With high strength material, the size of columns’ dimension is decreased, also the available space of buildings is increased.
However, the brittleness is the disadvantage of the high strength materials. Once the maximum concrete strength is reached, the construction will immediately be destroyed. Besides, Taiwan is located in a seismic belt, so the toughness is required for most of the buildings. The higher the toughness, the more it can reduce the strength caused by the earthquake. In order to increase the toughness in a traditional construction, adding new materials is one of the methods. According to the references, the toughness and the shear resistance in concrete materials are increased by adding the steel fiber into concrete. Also, the amount of the transverse steel is reduced and the process of tying steel cage is simplified. Moreover, adding the steel fiber can not only prevent the early cover spalling, but also restrain the cracks’ development that may cause immediate destruction.
The performance of high-strength steel fiber reinforced concrete columns under the condition of double curvature cyclic loading test is investigated in this study. The study can be divided into two parts. The first part is using the same designed strength to compare the differences between the original concrete and steel fiber concrete. The second part is the feasibility of substitution of the steel fiber for transverse steel based on the method that enlarging the spacing between transverse steel. Furthermore, not only the regression between the toughness of RC columns and the toughness of steel fiber RC columns was proposed in the study, but also the prediction formula. In addition, the relationship between the confinement effect that built by the prediction formula and the cyclic loading test is proposed in the study.目錄
口試委員會審定書 #
誌謝 ii
中文摘要 iii
ABSTRACT iv
目錄 v
表目錄 ix
圖目錄 x
照片目錄 xiv
參數對照表 xv
第一章、緒論 1
1.1 動機與目的 1
1.2 研究範圍與內容 3
1.3 研究流程 4
第二章、文獻回顧 5
2.1 圍束設計規範介紹 5
2.1.1 美國混凝土協會 ACI 318-11[5] 5
2.1.2 加拿大規範 CSA A23.3-04[6] 6
2.1.3 NCREE建議公式[7] 8
2.1.4 美國混凝土協會 ACI 318-14[12] 9
2.2 剪力設計規範介紹 11
2.2.1 美國混凝土協會 ACI 318-11[5] 11
2.2.2 Sezen 剪力預測公式[13] 13
2.3 撓曲強度 15
2.4 鋼纖維混凝土力學性質 18
2.4.1 鋼纖維添加至混凝土的力學性質影響 18
2.4.2 韌性指數定義 24
2.5 端鉤型鋼纖維拉拔能量 26
2.5.1 端鉤型鋼纖維拉拔機制 26
2.5.2 端鉤型鋼纖維拉拔能量預測模型 27
2.5.3 等效握裹強度 34
2.6 鋼纖維混凝土韌性參數 35
2.7 鋼筋混凝土柱韌性參數 36
2.7.1 鋼筋混凝土柱的圍束效應 36
2.8 韌性比回歸公式 39
2.8.1 鋼纖維混凝土的韌性比回歸公式 39
2.8.2 鋼筋混凝土的韌性比回歸公式 40
2.8.3 鋼纖維鋼筋混凝土柱的韌性比回歸公式 42
2.9 破壞模式 44
2.10 資料庫蒐集 46
第三章、實驗計畫 47
3.1 試驗背景 47
3.2 試體設計 47
3.2.1 設計細節 48
3.2.2 試體編號 53
3.3 試驗材料與配比 54
3.3.1 試驗材料 54
3.3.2 試驗配比 56
3.4 試驗儀器與設備 57
3.4.1 測試系統 57
3.4.2 內部量測系統 63
3.4.3 外部量測系統 71
3.4.4 其他 73
3.5 試體製作 75
3.5.1 應變計黏貼 75
3.5.2 試體澆置 77
3.6 破壞模式預測 80
3.7 測試流程 86
3.7.1 實驗前置 86
3.7.2 實驗進行 89
3.8 韌性比回歸公式 90
3.8.1 高強度鋼筋混凝土柱 90
3.8.2 高強度鋼纖維鋼筋混凝土柱 94
3.9 韌性比與反覆側推實驗修正公式 98
第四章、試驗結果 100
4.1 材料試驗 100
4.1.1 高強度鋼筋 100
4.1.2 高強度鋼纖維混凝土 107
4.2 反覆側推實驗 110
4.2.1 重要參數點 110
4.2.2 位移與遲滯迴圈 112
4.2.3 裂縫發展 122
4.2.4 鋼筋降伏時間 126
4.2.5 曲率量測 127
4.2.6 剪力位移量測 130
第五章、結果與討論 133
5.1 韌性比回歸公式驗證 133
5.1.1 高強度鋼筋混凝土柱 133
5.1.2 高強度鋼纖維鋼筋混凝土柱 134
5.2 韌性比與反覆側推實驗修正公式驗證 135
5.3 反覆側推實驗結果比較 136
5.3.1 位移與遲滯迴圈比較 136
5.3.2 消能機制與勁度衰減比較 146
5.3.3 鋼筋混凝土柱韌性比預測值與反覆側推實驗目標性能點比較 155
第六章、結論與建議 156
6.1 結論 156
6.2 建議 157
參考文獻 159
附錄A應變計分析 163
附錄B反覆側推實驗照片 210
附錄C混凝土材料檢驗報告 219
附錄D試體設計圖說 230
附錄E反覆側推實驗資料庫(橫箍柱) 23
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Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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