• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.532-535
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• 2004

This paper presents a nonlinear finite element analysis procedure for the prediction of shear strength of reinforced concrete deep beams. A computer program, named RCAHESTC(Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile. compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. The proposed numerical method for the prediction of shear strength of reinforced concrete deep beams is verified by comparison with the reliable experimental results.

• International Journal of Concrete Structures and Materials
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• 제19권1E호
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• pp.3-9
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• 2007

This paper presents a numerical procedure for analyzing the joints between precast post-tensioned segments. A computer program for the analysis of reinforced concrete structures was run for this problem. Models of material nonlinearity considered in this study include tensile, compressive and shear models for cracked concrete and a model for reinforcing steel with smeared crack. An unbonded tendon element based on the finite element method, that can describe the interaction between the tendon and concrete of prestressed concrete member, was experimentally investigated. A joint element is newly developed to predict the inelastic behavior of the joints between segmental members. The proposed numerical method for the joints between precast post-tensioned segments was verified by comparison of its results with reliable experimental results.

• 콘크리트학회논문집
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• 제12권6호
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• pp.83-90
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• 2000

This paper presents an analytical prediction of the elastic behavior of discontinuous displacement in reinforced concrete column-footing joint under earthquake. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, local discontinuous deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The proposed numerical method for hysteretic behavior of discontinuous displacement in reinforced concrete column-footing joint will be verified by comparison with reliable experimental results.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.591-598
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• 2003

The purpose of this study is to investigate the seismic behavior of reinforced concrete Containment Panel subjected to earthquake motions. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), was used for the analysis of reinforced concrete structures. A 4-node flat shell element with drilling rotational stiffness is used for spatial discretization. The layered approach is used to discretize behavior of concrete and reinforcement through the thickness. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. Solution of the equations of motion is obtained by numerical integration using Hither-Hughes-Taylor(HHT) algorithm. The proposed numerical method for the seismic analysis of reinforced concrete Containment panel is verified by comparison of analysis results with reliable experimental results.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.180-187
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• 2003

The purpose of this study is to investigate the seismic behavior of reinforced concrete shear wall subjected to earthquake motions. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), was used for the analysis of reinforced concrete structures. A 4-node flat shell element with drilling rotational stiffness is used for spatial discretization. The layered approach is used to discretize behavior of concrete and reinforcement through the thickness. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. Solution of the equations of motion is obtained by numerical integration using Hither-Hughes-Taylor(HHT) algorithm. The proposed numerical method for the seismic analysis of reinforced concrete shear wall is verified by comparison of analysis results with reliable experimental results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.442-445
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• 2006

This paper presents an analytical prediction of nonlinear characteristics and behavior characteristics PSC structures with un-bonded tendon system. In this paper, a numerical model for un-bonded tendon is proposed based on the finite element method, which can represent straight or curved un-bonded tendon behavior. this model and time-dependent material model used to investigate the time-dependent behavior of un-bonded prestressed concrete structures. The accuracy and objectivity of the assessment process may be enhanced by the use of sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of concrete structures and steel plate was used. The material nonlinearities are taken into account by comprising the tension, compression, and shear models of cracked concrete and models for reinforcements and tendons in the concrete. The smeared crack approach is incorporated. It accounts for the aging, creep and shrinkage of concrete and the stress relaxation of prestressed steel. The proposed un-bonded tendon model and numerical method of un-bonded prestressed concrete structures is verified by comparison with reliable experimental results.

• Computers and Concrete
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• 제16권6호
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• pp.825-846
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• 2015

In this study, shear tests on steel fiber reinforced-prestressed concrete (SFR-PSC) members were conducted with test parameters of the concrete compressive strength, the volume fraction of steel fibers, and the level of effective prestress. The SFR-PSC members showed higher shear strengths and stiffness after diagonal cracking compared to the conventional prestressed concrete (PSC) members without steel fibers. In addition, their shear deformational behavior was measured using the image-based non-contact displacement measurement system, which was then compared to the results of nonlinear finite element analyses (NLFEA). In the NLFEA proposed in this study, a bi-axial tensile behavior model, which can reflect the tensile behavior of the steel fiber-reinforced concrete (SFRC) in a simple manner, was introduced into the smeared crack truss model. The NLFEA model proposed in this study provided a good estimation of shear behavior of the SFRPSC members, such as the stiffness, strengths, and failure modes, reflecting the effect of the key influential factors.

• Structural Engineering and Mechanics
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• 제13권3호
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• pp.313-328
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• 2002

Based on the orthotropic hypoelasticity formulation, a triaxial constitutive model of concrete is proposed. To account for increasing ductility in high confinement of concrete, the ductility enhancement is considered using so called the strain enhancement factor. It is also developed a three-dimensional finite element model for reinforced concrete structural members based on the proposed constitutive law of concrete with the smeared crack approach. The concrete confinement effects due to the beam-column joint are investigated through numerical examples for simple beam and structural beam member. Concrete at compression fibers in the vicinity of beam-column joint behaves dominant not only by the uniaxial compressive state but also by the biaxial and triaxial compressive states. For the reason of the severe confinement of concrete in the beam-column joint, the flexural critical cross-section is observed at a small distance away from the beam-column joint. These observations should be utilized for the economic design when the concrete structural members are subjected to high confinement due to the influence of beam-column joint.

• 한국지진공학회논문집
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• 제5권4호
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• pp.39-49
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• 2001

이 논문에서는 주철근 단락을 갖는 철근콘크리트 교각의 내진성능평가를 위한 비탄성 해석 기법을 제시하였다. 하중의 단계에 따라 수반하게 되는 콘크리트의 균열 및 철근의 항복, 이로 인한 부착효과와 골재의 맞물림 현상 및 강도의 감소 등과 같은 재료적 비선형성을 고려하였다. 이에 대한 콘크리트의 균열모델로서는 분산균열 모델을 사용하였다. 두께가 서로 다른 부재간의 접합부에서 단면강성이 급변하기 때문에 생기는 국소적인 불연속변형을 고려하기 위한 경계면 요소를 도입하였다. 또한, 횡방향 구속철근으로 인한 강도의 증가 효과를 고려하였다. 이 연구에서는 주철근 단락을 갖는 철근콘크리트 교각의 내진성능평가를 위해 제안한 해석기법을 신뢰성 있는 연구자의 실험결과와 비교하여 그 타당성을 검증하였다.

• 한국지진공학회논문집
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• 제3권1호
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• pp.55-66
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• 1999

이연구에서는 반복적인 횡하중이 작용하고 있는 철근콘크리트 기둥의 비선형 이력거동 및 파괴거동을 해석적으로 예측할 수 있는 기법을 제시하였다 하중의 단계에 따라 수반하게 되는 콘크리트의 균일 및 철근의 항복 이로 인한 부착 효과와 골재의 맞물림 현상 및 강도의 감소 등과 같은 특성을 고려한 재료적 비선형성을 고려하였고 기둥부재에 일반적으로 배치되는 구속철근으로 인한 강도의 증가효과를 고려하였다. 여기서 철근콘크리트의 응력-변형도 관계는 분산균열모델에 기초하여 평균값으로 표현된다. 비교적 큰 압축하중과 함께 지진하중과 같이 큰 규모의 횡하중으로 인한 대변위 문제를 고려할 수 있도록 total Lagrangian formulation에 의한 기하학적인 비선형성을 고려하였다. 본 연구에서 작성한 유한요소 해석 프로그램에 의한 결과를 다른 연구자의 실험 결과와 비교함으로써 본 연구에서 제시한 해석기법의 타당성을 검증하였다.