• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.475-485
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• 2009

In this paper a two-step algorithm is proposed to efficiently generate rebar elements from 3D CAD data in the context of CAD/CAE data transfer. The first step is an algorithm to identify various type rebar objects and their attributes by analyzing 3D CAD data in STEP format, which is one of the international data standards. The second algorithmic step is a procedure to generate one-dimensional rebar elements from the object data made through the first step for finite element analysis or other CAE tasks. Successful rebar element data generation from real 3D CAD data for a reinforced concrete structure shows the efficacy of the proposed algorithm.

• Computational Structural Engineering
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• v.11 no.2
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• pp.57-69
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• 1998

이번 기사에서는 반복하중 하에서의 철근 콘크리트 구조물의 비선형 유한요소해석에 관한 연구를 정리한 CEB 보고서를 소개하고자 한다. 보고서의 분량이 190쪽으로 번역기사의 내용으로는 많지만, 매우 유익한 내용이라 생각되어 선택하였으며, 구체적인 수식은 생략하고 전반적인 내용의 흐름을 위주로 정리했다. 이 보고서의 내용은 콘크리트의 압축거동, 콘크리트의 인장거동, 철근의 거동, 콘크리트와 철근의 부착, 철근과 콘크리트 혹은 콘크리트와 콘크리트의 경계면 거동, 그리고 철근콘크리트의 유한요소모델링 등으로 이루어져 있다.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.1
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• pp.35-50
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• 2000

본 논문에서는 반복하중을 받는 철근 콘크리트 쉘구조물의 해석을 위한 비선형 유한요소 해법을 제시하였다 유한 요소로서는 충상화기법을 이용한 부재회전강성도를 갖는 4절점 평면 쉘요소가 개발되었다 두께 방향에 대한 철근과 콘크리트의 재료성질을 고려하기 위하여 충상화기법이 도입되었다. 재료적 비선형성에 대해서는 균열콘크리트에 대한 인장, 압축, 전단모델과 콘크리트중에 있는 철근모델을 조합하여 고려하였다. 이에 대한 콘크리트의 균열모델로서는 분산균열모델을 사용하였으며 철근에 대해서는 1축 응력상태로가정하여 등가의 분산 분포된 철근량으로 모델화하였다 구성모델은 재하, 제하 그리고 재재하과정을 포함하여 요소는 반복하중하에서 철근콘크리트 쉘의 거동을 파악할 수 있다 신뢰성 있는 실험결과와 비교를 통하여 본 논문의 해석방법이 반복하중을 받는 철근콘크리트 쉘구조의 비선형 해석에 적합한 방법임을 입증하고자 한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.10a
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• pp.90-96
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• 1992

경계면 요소를 이용하여 철근콘크리트 구조물의 접촉면 문제를 유한 요소법으로 해석하는 기법에 대하여 연구한다. 본 연구에서는 경계면 요소의 수치해석의 이론과정을 전개하고, 실험 관찰된 부착 시험체에 적용하여 이형철근과 콘크리트 부착기구의 접촉면을 해석한다. 경계면은 특별한 연결요소를 이용하여 재현하며 Mohr-Coulomb의 마찰 이론을 응응한다. 해석의 주요점으로 하중상태에 따라 변화되는 경계면의 접촉상태, 즉 고정(stick), 미끄러짐(slide), 분리(separation)를 묘사하여 경계면 재료의 비선형 거동을 관찰한다. 부착모델의 해석결과는 실험실의 결과와 대체로 일치되며 따라서 철근콘크리트 접촉면의 응력해석을 위해 경계면 요소가 활용될 수 있음을 보여준다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.247-249
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• 2013

열화한 철근콘크리트 구조물에 대하여 성능회복을 위하여 전기화학적 방식, 단면복구공법, 균열보수공법, 표면마감공법 등이 상용되고 있다. 본 연구에서는 단면복구공법의 적용과 성능예측을 위한 해석 모델의 입력값으로 사용될 보강철근과 단면복구재의 부착특성을 평가하기 위하여 철근인발실험을 실시하였다. 폴리머시멘트몰탈이 사용되었으며 부착요소의 강성과 강도를 구하여 비선형 해석을 실시하여 상당한 정확도의 예측값을 도출하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.237-246
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• 2006

In order to evaluate the seismic performance of damaged reinforced concrete members, particularly bridge piers, an inelastic time-dependent element is proposed. The proposed element enables increased characteristics due to structural intervention(i.e., repair or retrofitting) to be accurately reflected to the degraded strength and stiffness of the members. The inelastic time-dependent element having both birth and death time can freely be activated within the user-defined time intervals during static and dynamic time-history analysis. Comparative studies are carried out for reinforced concrete bridge piers that are repaired and retrofitted. Analytical predictions using the developed element show reasonable correlation with experimental results. Also conducted is a nonlinear time-history analysis of a reinforced concrete bridge under multiple earthquakes. The comparative analytical results prove the validation of current development. In all, it is concluded that the present element is capable of providing salient features for the healthy evaluation of seismic performance and hence seismic stability assessment of RC bridge piers being repaired and retrofitted.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.547-554
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• 2016

In this study, nonlinear finite element analysis based on the Modified Compression Field Theory has been conducted to evaluate shear strength of RC walls with opening. On the analysis, reinforcement ratio within development length of rebars nearby the opening was reduced in the model in order to investigate the effect of opening on shear strength of RC shear walls. The nonlinear finite element analysis has been verified through comparison with the test result in literature. Through the verification, it was investigated that the analysis considering the development length of rebars well reflected the effect of an opening on shear strength of RC shear walls while current design provisions did not reasonably consider one.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.201-202
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• 2009

The objective of this paper is to develop nonlinear analysis method using fiber element. The program is based on flexibility method and developed for analyzing bernoulli's beam element. Using fiber element, three dimensional effects, such as concrete confinement can be incorporated into the uniaxial stress-strain relationship. In addition, most appropriate modeling method is used for application of bond-slip and shear effects.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.5 s.45
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• pp.63-74
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• 2005

The purpose of this study is to assess the seismic performance of reinforced concrete bridge columns using inelastic finite element analysis. 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 reinforced concrete structures was used. Damage index aims to provide a means of quantifying numerically the damage in reinforced concrete bridge columns sustained under earthquake loading. The proposed numerical method for the seismic performance assessment of reinforced concrete bridge columns is verified by comparison with reliable experimental results.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.2 s.48
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• pp.31-38
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• 2006

The purpose of this study is to assess the seismic performance of reinforced concrete bridges using nonlinear finite element analysis. 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 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 is applied to reinforced concrete bridges and compared.