• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.148-151
• /
• 2011

현재 방폭설계 관련 설계지침은 기둥제거시나리오를 이용한 대체하중경로법을 주로 적용하고 있지만, 실제로 폭발이 발생하였을 때 기둥의 완전한 파괴가 일어나지 않을 경우 이 방식을 적용하는 것은 적합하지 않다. 따라서 본 논문에서는 비선형 동적 해석 프로그램인 AUTODYN을 이용해 편심하중을 받는 철근 콘크리트 기둥의 잔존 폭발 저항 성능을 평가하는 방식을 제안하였다. 해석결과를 비교해보면 TNT양과 축하중이 클수록 철근콘크리트 기둥의 잔존 폭발 저항 성능이 감소되었다. 이것은 폭발이 발생하기전의 기둥의 편심하중에 의한 응력상태에 따라 폭발 저항 성능이 달라짐을 알 수 있다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.19 no.1 s.71
• /
• pp.1-13
• /
• 2006

An analytical procedure to analyze reinforced concrete(RC) beams and columns subject to monotonic and cyclic loadings is proposed on the basis of the layered section method. In contrast to the classical nonlinear approaches adopting the perfect bond assumption, the bond slip effect along the reinforcing bar is quantified with the force equilibrium and compatibility condition at the post cracking stage and its contribution is implemented into the reinforcing. The advantage of the proposed analytical procedure, therefore, will be on the consideration of the bond slip effect while using the classical layered section method without additional consideration such as taking the double nodes. Through correlation studies between experimental data and analytical results, it Is verified that the proposed analytical procedure can effectively simulate the cracking behavior of RC beams and columns accompanying the stiffness degradation caused by the bond slip.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.6 no.3
• /
• pp.11-21
• /
• 2002

The evaluation of displacement ductility is performed by direct method through tracking the inelastic hysteretic behavior of RC bridge columns subject to cyclic loading using a flexibility-based fiber element mode. To reasonably track the inelastic behavior until the RC bridge column reaches its ultimate state, the average stress-average strain relations and joint elements, which agree well with experiments, are modified and applied considering the tension stiffening behavior and discontinuous displacement between the column and its base. In addition the evaluation of displacement ductility is performed by a direct method easily applicable to numerical analysis. Locations for the integration points, values for the post-crushing concrete strength and low-cycle fatigue failure of longitudinal reinforcement that affect the calculation of yielding and ultimate displacements are proposed for the application to flexibility-based fiber element model. Since less than 10% of error occurs during the displacement ductility analysis, the yielding and ultimate displacements evaluated by the applied analysis method and model appear to be valid.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.549-552
• /
• 2008

Corrosion of reinforcing steel is prohibited under normal condition by the alkalinity of the pore water in the concrete. But the probability of steel corrosion becomes higher when the chloride ions are introduced into the concrete. Steel corrosion is decisive factor for the determination of service life of the marine concrete structures because chloride ions are abundant in the sea. In this paper, chloride penetration analysis for the rectangular pier in the marine environment is performed considering the diffusion movement of chlorides. Result reveals that the chloride concentration in the corner bar is higher than that of in the side bar with rectangular pier. Also the time to the specified accumulation of chloride in the corner bar is much shorter than that in the side bar. Because the corrosion initiation time of corner bar is half as much as that of side bar, service life for the rectangular pier in marine environment should be determined with respect to the coner bar.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.8 no.5 s.39
• /
• pp.15-24
• /
• 2004

The purpose of this study is to investigate the inelastic behavior and ductility capacity of reinforced concrete bridge piers including P-delta effects. 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. In addition to the material nonlinear properties, the algorithm for large displacement problem that may give an additional deformation has been formulated using total Lagrangian formulation. The proposed numerical method for the inelastic behavior and ductility capacity of reinforced concrete bridge piers is verified by comparison with reliable experimental results.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.391-402
• /
• 1994

One of the most important design concept for reinforced concrete structures is to achieve a ductile failure mode, and also moment redistribution for economic design is possible in case that adequate ductility is provided. Flexural ductility index is, therefore, used as a reference for possibility of moment redistribution as well as for prediction of flexural behavior of designed R.C. structures. Ductility index equations, however, provide approximate values due to the linear concrete compressive stress assumption at the tension steel yielding state. Theoretically more exact ductility index is calculated by a numerical analysis with the realistic stress-strain curves for concrete and steel to be compared with the result from tire ductility index equations. Variation of ductility index for the selected variables and the reasonable maximum tension steel ratio for doubly reinforced section are investigated. A moment-curvature curve model is also proposed for future research on moment redistribution.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.9 no.2 s.42
• /
• pp.29-36
• /
• 2005

The purpose of this study is to investigate the inelastic behavior of reinforced concrete bridge columns with unbonding of main reinforcements at plastic hinge region. 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 effect of unbonding of main reinforcements at plastic hinge region has been also taken into account to model the concrete and reinforcing steel. The proposed numerical method for the inelastic behavior of reinforced concrete bridge columns with unbonding of main reinforcements at plastic hinge region is verified by comparison with reliable experimental results.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.10a
• /
• pp.433-439
• /
• 1996

본 논문에서는 스트럿-타이 모델을 이용한 콘크리트 구조물의 설계 및 해석과정에서 필요로 하는 스트럿 유효강도의 결정 및 절점영역 지지력의 검토를 일반적이고 일관성 있게 수행할 수 있는 방법을 제안하였다. 콘크리트 스트럿의 유효강도는 스트럿-타이 모델의 스트럿 영역에 해당되는 유한요소들의 주응력비를 고려하여 결정하였으며, 스트럿의 기하하적인 형상을 이용하여 형성된 절점영역의 지지력은 조합응력을 받는 콘크리트의 파괴기준을 고려하는 비선형 유한요소 해석을 이용하여 검토하였다. 제안한 방법을 예증하기 위해 실험된 철근콘크리트 보의 해석을 스트럿-타이 모델 방법을 이용하여 실시하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.484-487
• /
• 2010

본 논문에서는 BIM(Building Information Modeling)의 핵심기술인 파라메트릭 기술을 기반으로 하여 철근콘크리트 구조물의 기둥부재 주철근 자동배근시스템을 구축함으로써 기존 프로그램에서 사용자가 직접 입력해야하는 변수의 수를 최소화하고 사용성과 정확성을 높이는 것을 목적으로 한다. 기존 철근배근 형상 자동 모델링에서 기둥철근의 자동 모델링은 기둥단면이 변하는 부분에서의 철근 배근과 정착 및 이음길이를 고려하지 않고 있다. 만약 고려하더라도 이용자가 직접 입력하는 방식이기 때문에 규모가 큰 건물일 경우 방대한 정보의 처리 미숙으로 인해 정확한 모델링을 기대하기 어려운 실정이다. 본 연구에서는 기둥 부재에 대하여 대상 건물을 선정하고 구조해석 모델링을 구축한 후 구조해석 결과 데이터베이스를 추출하여 얻은 정보와 건축구조설계기준에 따른 정착 및 이음 길이 산정에 관한 알고리즘을 구축하여 철근배근 형상 자동화 모듈에 적용하여 배근 자동 설계 및 자동 형상화 모듈을 생성하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.3
• /
• pp.384-391
• /
• 2012

In this paper, reinforced concrete structures are modeled and analyzed. Reinforced concrete has been an essential element in the construction and one that is provided for shielding effectiveness at particular frequencies by rebar placed as a set up in the form of a grid. Using commercial 3-dimensional electromagnetic(3D EM) tool to analyze the reinforced concrete structure, the procedure of analysis for reinforced concrete is computed by dividing concrete, rebar and entire reinforced concrete. The spacing of rebar is bigger, transmission coefficient is higher and the diameter of rebar is bigger, transmission coefficient is lower. Also, in case of two layers is analyzed by gap of layers. Using single layer rebar that thickness of rebar given by 10, 20 and 30 mm have transmission coefficient of -1.89, -2.73 and -4.76 dB/10 cm at 500 MHz. Also, two layers rebar obtain -1.89, -2.73 and -4.76 dB/10 cm for same conditions.