• Title/Summary/Keyword: bond-slip behavior

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Nonlinear Analysis of Prestressed Concrete Containment Structures Considering Slip Behavior of Tendons (긴장재의 슬립거동을 고려한 원자로 격납건물의 비선형 해석)

  • Kwak Hyo-Gyoung;Kim Jae-Hong;Kim Sun-Hoon;Chung Yun-Suk
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.4 s.70
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    • pp.335-345
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    • 2005
  • This paper concentrates on the nonlinear analysis of prestressed concrete (PSC) containment structures. Unlike a commercialized program which adopts the perfect bond assumption between concrete and tendon in the analysis of PSC structures, a numerical algorithm to consider the slip effect, simultaneously with the use of commercialized programs such as DIANA and ABAQUS, is introduced in this paper For bonded tendons, the apparent yield stress of an embedded tendon is determined from the bond slip relationship. And for unbonded tendons, Correction for the strength and stiffness of unbonded internal tendons is achieved on the basis of an iteration scheme derived from the slip behavior of tendon along the entire length. Finally, the developed algorithm is applied to two PSC containment structures of PWR and CANDU to verify its efficiency and applicability in simulating the structural behavior of large complex structures, and the obtained result shows that both containment structures represent the ultimate pressure capacity larger than about 3 times of the design pressure.

High Performance Fiber Reinforced Cement Composites with Innovative Slip Hardending Twisted Steel Fibers

  • Kim, Dong-Joo;Naaman, Antoine E.;El-Tawil, Sherif
    • International Journal of Concrete Structures and Materials
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    • v.3 no.2
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    • pp.119-126
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    • 2009
  • This paper provides a brief summary of the performance of an innovative slip hardening twisted steel fiber in comparison with other fibers including straight steel smooth fiber, high strength steel hooked fiber, SPECTRA (high molecular weight polyethylene) fiber and PVA fiber. First the pull-out of a single fiber is compared under static loading conditions, and slip rate-sensitivity is evaluated. The unique large slip capacity of T-fiber during pullout is based on its untwisting fiber pullout mechanism, which leads to high equivalent bond strength and composites with high ductility. Due to this large slip capacity a smaller amount of T-fibers is needed to obtain strain hardening tensile behavior of fiber reinforced cementitious composites. Second, the performance of different composites using T-fibers and other fibers subjected to tensile and flexural loadings is described and compared. Third, strain rate effect on the behavior of composites reinforced with different types and amounts of fibers is presented to clarify the potential application of HPFRCC for seismic, impact and blast loadings.

A numerical tension-stiffening model for ultra high strength fiber-reinforced concrete beams

  • Na, Chaekuk;Kwak, Hyo-Gyoung
    • Computers and Concrete
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    • v.8 no.1
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    • pp.1-22
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    • 2011
  • A numerical model that can simulate the nonlinear behavior of ultra high strength fiber-reinforced concrete (UHSFRC) structures subject to monotonic loadings is introduced. Since engineering material properties of UHSFRC are remarkably different from those of normal strength concrete and engineered cementitious composite, classification of the mechanical characteristics related to the biaxial behavior of UHSFRC, from the designation of the basic material properties such as the uniaxial stress-strain relationship of UHSFRC to consideration of the bond stress-slip between the reinforcement and surrounding concrete with fiber, is conducted in this paper in order to make possible accurate simulation of the cracking behavior in UHSFRC structures. Based on the concept of the equivalent uniaxial strain, constitutive relationships of UHSFRC are presented in the axes of orthotropy which coincide with the principal axes of the total strain and rotate according to the loading history. This paper introduces a criterion to simulate the tension-stiffening effect on the basis of the force equilibriums, compatibility conditions, and bond stress-slip relationship in an idealized axial member and its efficiency is validated by comparison with available experimental data. Finally, the applicability of the proposed numerical model is established through correlation studies between analytical and experimental results for idealized UHSFRC beams.

Fatigue Behavior of RC Elements under High Cyclic Loading (사용반복하중에 대한 철근콘크리트 부재의 피로거동)

  • 강보순;심형섭;황성춘
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.1161-1166
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    • 2001
  • Fatigue behavior of reinforced concrete(RC) elements has been experimentally and analytical investigated. Fatigue behavior influenced by longitudinal reinforcement ratio, strength of concrete and load ratio $P_{u}$/ $P_{o}$. The purpose of these studies is to propose an empirical formula for fatigue behavior on basis of experimental results. Also an analytical method to predict the crack propagation of RC beams has been developed based on the relationships between bond stress and slip.

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Fatigue behavior of RC Beams under High Cycle Loading (사용반복하중에 대한 철근콘크리트 보의 피로거동)

  • 강보순;황성춘
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11a
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    • pp.499-503
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    • 2001
  • Fatigue behavior of reinforced concrete (RC) elements has been experimentally and analytical investigated. Fatigue behavior influenced by longitudinal reinforcement ratio, strength of concrete and load ratio P/sub u//P/sub o/. The purpose of these studies is to propose an empirical formula for fatigue behavior on basis of experimental results. Also an analytical method to predict the crack propagation of RC beams has been developed based on the relationships between bond stress and slip.

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Crack Behavior of RC Structures under High Cycle Loading (사용피로하중에 대한 철근 콘크리트 구조물의 균열특성)

  • Kang Bo-Soon
    • Journal of the Korean Society for Railway
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    • v.8 no.6 s.31
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    • pp.495-499
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    • 2005
  • Fatigue behavior of reinforced concrete(RC) elements has been experimentally and analytical investigated. Fatigue behavior is influenced by a longitudinal reinforcement ratio, strength of concrete and a load ratio Pu/Po. The purpose of this study to propose an empirical formula for the fatigue behavior on the basis of experimental results. Also an analytical method to predict the crack propagation of RC beams has been developed based on the relationships between bond stress and slip.

Nonlinear Analysis of RC Beams under Cyclic Loading Based on Moment-Curvature Relationship. (모멘트-곡률 관계에 기초한 반복하중을 받는 철근콘크리트 보의 비선형 해석)

  • 곽효경;김선필
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2000.10a
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    • pp.190-197
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    • 2000
  • A moment-curvature relationship to simulate the behavior of reinforced concrete beam under cyclic loading is introduced. Unlike previous moment-curvature models and the layered section approach, the proposed model takes into consideration the bond-slip effect by using monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The advantages of the proposed model, comparing to layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures. The modification of the moment-curvature relation to reflect the fixed-end rotation and pinching effect is also introduced. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed model.

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A new approach for nonlinear finite element analysis of reinforced concrete structures with corroded reinforcements

  • Shayanfar, Mohsen A.;Safiey, Amir
    • Computers and Concrete
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    • v.5 no.2
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    • pp.155-174
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    • 2008
  • A new approach for nonlinear finite element analysis of corroded reinforcements in RC structures is elaborated in the article. An algorithmic procedure for producing the tension-stiffening curve of RC elements taking into consideration most of effective parameters, e.g.: the rate of steel bar corrosion, bond-slip behavior, concrete cover and amount of reinforcement, is illustrated. This has been established on both experimental and analytical bases. This algorithm is implemented into a nonlinear finite element analysis program. The abilities of the resulted program have been studied by modeling some experimental specimens showing a reasonable agreement between the analytical and experimental findings.

Nonlinear Analysis of RC Columns under Cyclic Loading Based on Moment-Curvature Relationship (반복하중을 받는 RC기둥의 비선형 해석을 위한 모멘트-곡률 관계의 개발)

  • 곽효경;김선필
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.3-11
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    • 2002
  • A moment-curvature relationship to simulate the behavior of reinforced concrete (RC) columns under cyclic loading is introduced. Unlike previous moment-curvature models and the layered section approach, the unposed model takes into account the bond-slip effect by using a monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The pinching enact caused by axial force is considered with an assumption that the absorbing energy corresponding to any deformation level maintains constant regardless of the magnitude of applied axial force. The advantages of the proposed model, comparing tn layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures.. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed mood.

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Evaluation of Bond Behavior of Reinforced Concrete Beams with High-Strength Transverse Reinforcement (고강도 횡보강근을 사용한 철근콘크리트 보의 부착 거동 평가)

  • Kim, Sang-Woo;Kim, Young-Sik;Baek, Seung-Cheol;Kim, Kil-Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.5
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    • pp.102-109
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    • 2010
  • This paper investigates the bond behavior of reinforced concrete beams having high-strength transverse reinforcement. A total of four reinforced concrete beams were tested in this study to estimate the bond capacity of the proposed U-shape reinforcement. The proposed U-shape reinforcement not only has a simple structure to install, but also can increase the bond capacity of reinforced concrete beams by controling bond cracks. This study follow the test method proposed by Ichinose to obtain the bond stress and the bond slip of the specimens. The main test parameters were the yield strength, ratio, and reinforcing types of transverse reinforcements. It was found that the proposed U-shape reinforcement was able to effectively improve the bond performance of reinforced concrete beams with high-strength transverse reinforcement.