高強度鋼纖維混凝土柱剪力行為研究

Shear Behavior of High Strength Steel Fiber Reinforced Concrete Columns

韋思拿(Wisena Perceka)

指導教授 ： 廖文正

國立臺灣大學/工學院/土木工程學研究所/博士(2019年)

https://doi.org/10.6342/NTU201900617

摘要

無資料

關鍵字

單調側向曲線 ； 高軸向載荷 ； 軸向負荷低 ； 等效橫向鋼筋 ； 剪切破壞 ； 剪切屈曲失效 ； 剪切強度 ； 鋼纖維 ； 韌性比

並列摘要

The main objectives of this study is to provide a comprehensive understanding of the overall shear behavior of SFRC columns made of high strength concrete and steel rebars subjected to lateral cyclic and axial compression loading. Experimental and analytical studies were performed.
This research is divided into two phases. The first phase presented preliminary studies regarding compressive stress-strain behavior of SFRC material, steel fiber pullout, confinement efficiency of SFRC column under uniaxial compression loading, and study on shear strength of high strength SFRC beam without stirrups. The second phase covered the experimental program and analytical studies of shear behavior of high strength SFRC column subjected to displacement reversals and constant axial compression loading. Eight high strength double-curvature half-scale SFRC columns with rectangular section and aspect ratio of 3 were prepared to test. The double-curvature cyclic tests with constant axial compression load were performed on Multi Axial Testing System (MATS) in Structural Laboratory in National Centre for Research on Earthquake Engineering (NCREE) Taiwan. The steel fibers used were high strength hooked-end steel fiber with tensile strength of 2300 MPa. The applied axial compression load ratios ranged from 0.1 to 0.4 and the fiber volume fractions were 0.75% and 1.5%.
The preliminary studies present that the proposed stress-strain model had good agreement with the test results. Also, the study on steel fiber pullout showed that analytical model could predict the test result. Quantify confinement efficiency of SFRC column under uniaxial compression loading is based on toughness ratio, since it describes the energy dissipation capability. The proposed shear strength equation for SFRC beam was conservative, compared to shear strength of beams failing in shear.
The test results from 8 half-scale double curvature SFRC columns showed that all specimens failed in shear prior to flexural. The specimens under low axial load failed in shear and could maintain their axial capacities at the end of test, while the failure modes of specimens under axial compression load ratio of 0.3 and 0.4 were shear-buckling failure. The effect of steel fiber on columns under the same axial loading level was able to improve column shear strength and post peak behavior. Moreover, on columns with the same fiber volume fraction, increasing axial load increased shear strength, but turned the post-peak behavior to be more brittle. The proposed shear strength equation shows conservative results. The equivalent confinement based on toughness ratio is acceptable to be applied to equation for constructing the descending branch of backbone curve. The proposed backbone curves, on average, can be acceptable to estimate the measured envelope curve. The column model is created using OpenSees as 1D equivalent cantilever column model with fiber section and two springs placed at column based. This 1D model is reliable when the aim is only to construct the hysteresis loop of a SFRC column under static cyclic and axial compression loading.

並列關鍵字

backbone curve ； high axial load ； low axial load ； equivalent transverse reinforcement ； shear failure ； shear-buckling failure ； shear strength ； steel fiber ； toughness ratio

參考文獻

1. ACI Committee 374 (2005), “Acceptance Criteria for Moment Frames Based on Structural Testing (ACI 374.1-05) and Commentary,” American Concrete Institute, 9 pp.

2. ACI Committee 544 (2008), “State-of-the-Art Report on Fiber Reinforced Concrete – ACI 544.1R – 96 (Reapproved 2002),” ACI Manual of Concrete Practice, Part 6, 2008, pp. ACI544.1R-7 – ACI544.1R-24.

3. ACI Committee 318 (2011), "Building Code Requirements for Structural Concrete (ACI 318-11) and Commentary (318R-11),” American Concrete Institute, Farmington Hills, MI, 503 pp.

4. ACI Committee 318 (2014), "Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (318R-14),” American Concrete Institute, Farmington Hills, MI, 520 pp.

5. ACI Innovation Task Group 4 (2007), “Report on Structural Design and Detailing for High-Strength Concrete in Moderate to High Seismic Applications (ITG-4.3R-07),” American Concrete Institute, 62 pp.