臺灣博碩士論文加值系統

混凝土局部加載之承壓強度
研 究 生：吳世紀
指導教授：林草英
時 間：90年7月
論 文 摘 要
本研究經由試驗方式探討混凝土在不同型式之圍束作用下，受局部加載作用時之結構行為。試驗中共製作十四支混凝土試體，除一支為純混凝土試體外，其餘為以方形箍筋、圓形箍筋、全面鋼板環繞包裹及局部鋼板環繞包裹等之圍束配置方式及圍束位置之試體，分別探討於無偏心及偏心局部加載之情形下對混凝土承壓強度及其結構行為之影響。
試驗結果顯示，配置圍束材能有效提升混凝土局部承載強度，以箍筋作圍束之試體中，圓形箍筋之圍束效應較方形箍筋高，獲致較佳之圍束效果，而在箍筋之配置上，箍筋集中於上部所得之承載力又比均佈配置者為高；以鋼板作圍束之試體中，在相同用鋼量下，採用較厚之鋼板作局部圍束之試體較採用厚度較薄全面圍束者為佳；而於局部鋼板包裹之配置位置上，以中間偏上配置之圍束效果最佳，緊臨上部圍束之試體因破裂機制，效果較差；而在加載位置之影響中，使用圍束之試體於偏心加載時因三角錐外側混凝土圍束效果減少而降低試體承載力，惟其接近圍束材加載時，其圍束效應較大，構件在偏心加載時之承載強度取決於二者間合作用之機制。

The Bearing Strength of Concrete
Loaded Over Limited Area
Graduate Student：Wu Shih-Chi
Thesis Advisor：Lin Cao-Ying
ABSTRACT
The objectives of this research were to study the behavior of concrete when it was loaded over a limited area with different confining patterns . A total of 14 specimens, include 1 plain concrete block and the other 13 concrete blocks were confined by square hoop or circular hoop; overall surrounded or partial surrounded steel plate to study the effect of confining pattern and location of confinement on bearing capacity and structural behavior under concentric and eccentric load.
Based on results of the test, the arrangement of confining materials could effectively increase the concrete bearing capacity loaded under limited area. For the specimens confined with reinforcing hoop, the confining effect of circular hoop can achieve larger bearing capacity than the square hoop. When the circular hoop was arranged among different positions, hoop that concentrate on the upper part could develop higher bearing strength. For specimens confined with steel plate, the specimen with thicker one but confined locally showed better confining effect than the thinner one that surrounded over entire area. Furthermore , the steel plate located slightly above mid-high had the best confining effect. However, due to crack mechanism, when the steel plate was placed exactly to the upper edge showed worst confining effect. For the loading position, eccentrical load tended to decrease the concrete bearing capacity owing to the reduction in concrete confining area, however the confining effect was enhance when the load position was closer to the confining materials. Therefore, the bearing capacity of a confined column under different loading position tends to depend upon the mechanism of these two contribution factors.

目 錄
目錄…………………………………………………………………Ⅰ
表目錄………………………………………………………………Ⅳ
圖目錄………………………………………………………………Ⅴ
符號說明………………………………………………………………XI
第一章 緒論………………………………………………………1
1.1 研究動機……………………………………………1
1.2 研究目的與內容……………………………………3
第二章 文獻回顧…………………………………………………5
2.1 混凝土局部承載強度之相關研究…………………5
2.2 箍筋對混凝土圍束效應之相關研究………………8
第三章 試驗規畫與執行………………………………………14
3.1 試驗規畫……………………………………………14
3.2 試體製作……………………………………………14
3.2.1試體之材料…………………………………14
3.2.2模板組合……………………………………16
3.2.3試體之製作程序……………………………16
3.2.4試體編號……………………………………18
3.3 試驗作業…………………………………………19
3.3.1試驗作業流程………………………………19
3.3.2試驗設備……………………………………21
第四章 試驗結果之分析與討論……………………………………22
4.1 結構行為…………………………………………22
4.1.1 純混凝土試體………………………………22
4.1.2 箍筋圍束之試體……………………………22
4.1.3 鋼板圍束之試體……………………………26
4.2 承壓強度…………………………………………32
4.2.1 箍筋形狀之影響……………………………33
4.2.2 圓形箍筋位置之影響………………………34
4.2.3 圍束鋼板形狀之影響………………………34
4.2.4 局部圍束鋼板位置不同之影響……………35
4.2.5 加載位置之影響……………………………36
4.3 破壞機制……………………………………………37
4.3.1 純混凝土試體………………………………37
4.3.2 受鋼板圍束之試體…………………………37
4.3.3 受鋼筋圍束之試體…………………………39
4.4 圍束效應……………………………………………41
4.4.1圍束材料拉力與承壓強度之關係…………42
4.4.2圍束效應與承壓強度之關係………………43
第五章 結論與建議………………………………………………48
5.1 結論………………………………………………48
5.2 建議………………………………………………49
參考文獻……………………………………………………………52

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