• Title, Summary, Keyword: 인장거동

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The Design Guidelines for the Tensile Behavior of Ultra-High Performance Concrete (초고성능 콘크리트의 인장거동 설계기준 정립에 관한 연구)

  • Kang, Su-Tae;Joh, Chang-Bin;Park, Jong-Sup;Park, Jung-Jun;Ryu, Gum-Sung;Kim, Byung-Suk
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.361-364
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    • 2008
  • To design structures with Ultra High Performance Concrete (UHPC), it is necessary to estimate the mechanical properties first of all. The most attractive characteristics of UHPC are the considerable tensile strength and behavior. Therefore the most important thing in order to properly design UHPC structures is to establish the constitutive model to represent the tensile behavior of UHPC. In this study, it was tried to find out the tensile behavior of UHPC by experiments and analyses. Through comparisons with the French SETRA/AFGC recommendations and the Japanese recommendations for the Ultra High-Strength Fiber-Reinforced Concrete Structures, a reasonable model which could represent the tensile stress-strain relationship in the structural design was proposed

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Experimental study on the relationship between direct tensile stress and crack opening displacement of UHPC (UHPC의 직접인장응력과 균열개구변위와의 관계에 관한 실험적 연구)

  • Kang, Su-Tae;Park, Jung-Jun;Ryu, Gum-Sung;Koh, Gyung-Taek;Kim, Sung-Wook
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.433-436
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    • 2008
  • In order to estimate the mechanical properties of ultra high performance concrete, the most important is to evaluate its tensile behavior. The tensile behavior of concrete is generally characterized by the elastic behaviour before cracking and tensile stress-crack width relationship after cracking. We carried out the direct tensile and flexural tensile test and compared the tensile behaviors obtained by the direct tensile test and by inverse analysis of the flexural tensile test results. We compared the obtained tensile behavior with that of JSCE recommendations for ultra high performance concrete as well. we could see that the tensile stress-crack width relationship obtained from the flexural tensile test results using inverse analysis had good agreement with directly obtained tensile behaviour with direct tensile test and showed similar tensile softening behaviour introduced in JSCE recommendations for ultra high performance concrete.

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Tensile Stress-Strain Relation of ECC (Engineered Cementitious Composite) Accounting for Bridging Curve (실제 균열면응력-변위 곡선을 고려한 ECC의 1축 인장거동 관계)

  • Kim, Jeong-Su;Lee, Bang Yeon;Kwon, Seong-Hee;Kim, Jin-Keun;Kim, Yun Yong
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.933-936
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    • 2008
  • An engineered cementitious composite (Engineered Cementitious Composite) had been developed in previous study. Theoretical prediction of the tensile stress-strain relation of ECC is important in providing the material constitutive relation necessary for designing structural members. But, few studies have been reported with regard to predicting the tensile stress-strain relation of ECC. Prediction of the tensile stress-strain relation of ECC accounting for actual bridging curve, such as fiber dispersion is needed. The present study extends the work as developed by Kanda et al., by modeling the bridging curve, accounting for fiber dispersion, the degree of matrix spalling, and fiber rupture to predict the tensile stress-strain relation of ECC. The role of material variation in the bridging curve, such as number of effective fiber actually involved in the bridging capacity and how it affects the multiple cracking process is discussed. The approach for formulating the tensile stress-strain relation is discussed next, where the procedure for obtaining the necessary parameters, such as the crack spacing, is presented. Finally, the predicted stress-strain relation will be validated with experimental tests results.

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Flow-dependent Fiber Orientation Distribution and Its Effect on the Tensile Behavior of Intra High Performance Cementitious Composites (유동에 따른 섬유 방향성 분포특성 변화가 초고성능 시멘트 복합체의 인장거동에 미치는 영향)

  • Kang, Su-Tae;Kim, Jin-Keun
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.483-484
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    • 2010
  • In this paper, it was intended to understand the effect of the fiber orientation distribution on the tensile behavior of Intra High Performance Cementitious Composites (UHPCC) and to estimate flow-dependent fiber orientation distribution and the corresponding tensile behavior of UHPCC.

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Prying Action of Spliced Reinforcements in Tension (인장 겹침이음에서 프라이 거동의 영향)

  • Chun, Sung-Chul;Choi, Dong-Uk;Ha, Sang-Su;Oh, Bo-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.1085-1088
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    • 2008
  • Splice of reinforcement is inevitable in reinforced concrete structures and, generally, lap splices are used. Lap length for tension splice is determined from development length in tension. The development length is calculated from an experimental model which was based on data of tests on anchorage and splice. Longitudinal reinforcements in flexural members are deformed and, therefore, prying action happens in spliced reinforcements unlike anchored reinforcements. The prying action induces tensile stress in cover concrete and this tensile stress plays the same role to a circumferential tensile stress caused by bond. Because splitting failure is assumed to occur when the summation of tensile stresses caused by the prying action and the bond is equal to the tensile strength of the concrete, the prying action reduces the bond strength of spliced reinforcements. A theoretical model for the prying action is developed and effects of the prying action on the bond strength are assessed. The tensile stress by the prying action is proportional to tensile strength and modulus of elasticity of reinforcements. In addition, the tensile stress is inversely proportional to spacing of reinforcements. Consequently, longer splice length is required for spliced reinforcements with small spacing in flexible members.

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Study on ECC Tensile Behavior due to Constrained Drying Shrinkage (구속된 건조수축에 따른 ECC의 인장거동에 관한 연구)

  • Lee, Do-Keun;Lee, Kyoung-Chan;Lee, Chi-Dong;Shin, Kyung-Joon
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.4
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    • pp.367-374
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    • 2019
  • Drying shrinkage in the hardened cement is known to change in volume by decreasing the moisture content in the hardened body, and it is known that the higher the W / C and the higher the content of the paste, the larger the drying shrinkage. In the case of ECC, more drying shrinkage occurs compared to concrete, since it does not contain coarse aggregate. Since ECC is an important material for tensile performance, the effect of restrained tensile stress on mechanical tensile behavior should be considered. The purpose of this study is to analyze the effect of stress caused by restraint on the tensile behavior of ECC. The mechanical properties of the specimens were tested by uniaxial tension tests with different restraints. As a result, the difference of tensile behavior according to restraint stress was observed and the cause was analyzed.

GF/PE 복합계료의 인장파괴거동에 관한 연구

  • 엄윤성;최영근;고성위
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • pp.64-65
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    • 2003
  • 열경화성 수지를 사용한 복합재료의 연구결과들을 종합하여 보면 인장강도에 영향을 미치는 인자에 대한 다양한 연구결과가 있으나, 섬유함유율과 온도에 따른 인장파괴기구에 대한 고찰은 아직 희박한 실정이다. 따라서 이 연구에서는 열가소성 복합재료의 기계적 특성과 파괴거동에 관한 종합적인 연구의 일환으로 섬유함유율이 10%인 GF/PE 복합재료를 -5$0^{\circ}C$에서 6$0^{\circ}C$사이의 온도범위에서 인장시험을 통하여 임계 파괴에너지의 거동을 고찰하고, 각각의 온도범위에서의 파단면을 SEM사진을 통해 비교 검토하였다. (중략)

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Moment-Curvature Analysis of Steel Fiber-Reinforced Ultra High Performance Concrete Beams with Tension Softening Behavior (인장연화거동을 고려한 강섬유 보강 초고성능 콘크리트 보의 모멘트-곡률 해석)

  • Yang, In-Hwan;Joh, Chang-Bin;Kim, Byung-Suk
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.3
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    • pp.237-248
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    • 2011
  • Tensile softening characteristics play an important role in the structural behavior of steel fiber-reinforced ultra high performance concrete. Tension softening modeling and numerical analysis method are necessary for the prediction of structural performance of steel fiber-reinforced concrete. The numerical method to predict the flexural behavior is proposed in this study. Tension softening modeling is carried out by using crack equation based on fictitious crack and inverse analysis in which load-crack opening displacement relationship is considered. Thereafter material modeling is performed considering tension softening. The comparison of moment-curvature curves of the numerical analysis results with the test results indicates a reasonable agreement. Therefore, the present numerical results prove that good prediction of flexural behavior of steel fiber-reinforced ultra high performance concrete beams can be achieved by employing the proposed method.

Experimental Study on the Tensile Behaviors of Stud Connection with Hanger (행거로 보강된 스터드 접합부의 인장거동에 관한 실험적 연구)

  • Kim, Seung-Hun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.4
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    • pp.231-238
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    • 2004
  • This paper presents the tensile behavior of the stud connection between reinforced concrete(RC) and steel members. Hanger reinforcements are placed around the studs to transfer the tensile and flexural loads to the opposite side of the concrete member. Eight specimens for the tensile tests are tested with variables, which are the arrangement details of hanger reinforcements, the reinforcing bars, and the embedment length of stud. The results of the tensile tests show that hanger reinforcements are effective to increase tensile strength for stud connections. Hangers and reinforcing bars near stud bolts contributed to the reduction of brittle failure. From the evaluation on the tensile strength by previous design guidelines, it was shown that CCD (Concrete Capacity Design) method was more suitable for estimation of test strength.

Tensile Behavior of Ultra-High Performance Concrete According to Combination of Fibers (섬유 조합에 따른 초고성능 콘크리트의 인장거동)

  • Choi, Jung-Il;Koh, Kyung-Taek;Lee, Bang-Yeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.4
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    • pp.49-56
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    • 2015
  • Ultra-High Strength Concrete(UHPC) has ultra-high material performance including high strength and high flowability. On the other hand it is less ductile than high ductile fiber reinforced cementitious composite. This study investigated the effect of combination of steel fiber and micro fiber on the tensile behavior of UHPC. Four types of UHPC containing combination of steel fiber, polyethylene(PE), polyvinyl alcohol(PVA), and basalt fiber were designed. And then uniaxial tension tests were performed to evaluate the tensile behavior of UHPC according to combination of fibers. And density was measured to evaluate whether micro fiber induces unintentional high pore or not. From the test results, it was exhibited that PE fiber with high strength is effective to improve the tensile behavior of UHPC and basalt fiber is effective to increase the cracking and tensile strength of UHPC. Furthermore, it was also verified that micro fiber does not make high pore.