玻璃纖維加勁金屬螺紋管包覆混凝土柱之軸壓試驗與力學行為研究

Mechanical Behavior and Test of Axially Loaded Concrete-Filled Metal Spiral Tubes Wrapped with Glass Fiber-Reinforced Polymer (GFRP) Composites

譚晧祥(Hao-Hsiang Tan)

指導教授 ： 周中哲

共同指導教授 ： 李中生(Chung-Sheng Lee)

國立臺灣大學/工學院/土木工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.10800

摘要

本研究嘗試以新發展之”玻璃纖維加勁金屬螺紋管”做為混凝土的圍束裝置。此管將金屬螺紋管外表面以玻璃纖維紗束與樹脂填充形成平滑表面，再以玻璃纖維編織布纏繞包覆，形成內管壁具有螺紋狀環肋機構的複合材料管。此管除了提供內部填充混凝土橫向圍束效果之外，並利用內管壁的環肋與管內混凝土產生握裹作用來傳遞軸力，藉以使得外層纖維材料能夠有效的提供軸向強度。
為了探討”玻璃纖維加勁金屬螺紋管圍束混凝土”的實際力學行為，本研究將進行18組圍束混凝土柱軸壓試驗，每組試驗將測試二個試體。為了瞭解玻璃纖維加勁金屬螺紋管各層構件提供的圍束效應，分別進行以金屬螺紋管、玻璃纖維紗束加勁金屬螺紋管、以及再加上不同角度與層數纖維布包覆的圍束混凝土柱軸壓試驗。此外，規劃實心斷面、中空斷面以及在中空斷面內置入金屬螺紋管之圍束混凝土柱試體，藉以探討中空斷面柱之反應以及在不同束制條件下的圍束混凝土行為。試驗結果顯示，單純以金屬螺紋管提供的圍束效應不足以增加混凝土的強度，但是可以提高試體的變形量。當玻璃纖維加勁金屬螺紋管最外層以三層圍束方向纖維布包覆時，圍束混凝土試體強度可達到原來混凝土強度的兩倍；若是以兩層圍束方向纖維布以及一層軸向纖維布包覆時，軸向纖維材料亦能夠有效的提供軸向強度。試驗結果顯示，在外層複合材料破壞後金屬螺紋管持續提供圍束效應；另一方面，三種斷面形式的試體在初期彈性範圍內的行為非常接近，而中空斷面內置入金屬螺紋管的圍束效果則與實心試體相似。
在理論分析方面，本研究嘗試提出玻璃纖維加勁金屬螺紋管的圍束壓力計算方法，並利用學者Lee (2006)與Lee & Hegemier (2009)提出的圍束混凝土理論進行試驗結果的反算分析。從分析結果中顯示，本研究所提出的方法不僅能夠分別計算金屬螺紋管與玻璃纖維環肋的圍束應力，配合圍束混凝土理論(Lee, 2006; Lee & Hegemier, 2009)並且能夠準確地預測玻璃纖維加勁金屬螺紋管圍束混凝土柱在軸向壓力下的力學反應。對於圍束中空混凝土試體，本研究將中空斷面假設為良好圍束與無圍束區域，利用試驗結果回歸出隨著軸向應變變化的面積比，並提出可預測中空試體行為的計算方法。

關鍵字

金屬螺紋管 ； 複合材料 ； 圍束效應 ； 圍束混凝土 ； 軸壓

並列摘要

The purpose of this study is to observe the mechanical behavior of axial loaded concrete cylinders confined by a novel composite tube, which is consist of a metal spiral tube and Glass Fiber Reinforced Polymer (GFRP) composite shell. Filled by prepreg glass fiber stands, this novel tube features inner ribs that can efficiently transmit the axial force between the composite tube wall and concrete. In addition, this novel tube provides sufficient constrain on concrete dilatancy, which makes the material system become more robust and ductile.
To learn the performance of this novel composite tube, a total of 36 cylinder specimens confined were prepared and tested under uniaxial compression. On these specimens three types of tube confinement were designed: mental spiral tube, metal spiral tube with prepreg glass fiber stands, and mental spiral tubes with GFRP shell. Additionally, solid section, hollow section, and hollow section with interior mental spiral tube (HT) were made to study their influences to axial response. Test results show that the metal spiral tube increase the deformation but not the strength of concrete cylinder. Confined by mental spiral tube with GFRP shell, both the strength and ductility were raised up. After GFRP ruptured, the metal spiral tubes still contained the concrete. It is worth noting that three kinds of section had similar behavior in elastic range, and the confining effectiveness of HT section was similar to solid section.
Adopting a confined concrete theory (Lee, 2006; Lee & Hegemier, 2009) for back calculations, this study assesses the confining pressure from each composite tube. The behavior of these solid section specimens can be described by purposed methods with the adopted confine concrete theory. On the other hand, dividing the section into fully confined and unconfined areas, this study proposed a modified model to capture the response of hollow section specimens.

並列關鍵字

metal spiral tube ； GFRP ； confined concrete ； confinement ； axial compression

參考文獻

1. American Concrete Institute (ACI). (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening con-crete structures.” ACI 440.2R-08, Farmington Hills, Mich.

2. Bank L. C. (2006),”Composites for Construction: Structural Design with FRP Materials.” John Wiley & Sons, Inc.

3. Becque J, Patnaik AK, Rizkalla SH. (2003).” Analytical models for concrete confined with FRP tubes. Journal of Composites for Construction”, ASCE; 7(1):31–38.

4. Benham, P. P., Crawford, R. J., and Armstrong, C. G. (1996). Mechanics of engineering materials, 2nd Ed., Longman Group, Harlow, U.K.

5. Canadian Standard Association (CSA). (2002). “Design and construction of building components with fibre-reinforced polymers.” CSA-S806-02, Rexdale BD, Toronto.