• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.413-414
• /
• 2010

Many researchs shows that modulus of elasticity in manual overestimates real modulus of elasticity of concrete as strength gets higher. In 2007 KCI Manual, formula in modulus of elasticity has revised that it should be demonstrated. In this study, modulus of elasticity in high strength was estimated by experiment and experimental value was compared with manual value.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.141-144
• /
• 2008

Deflection in terms of serviceability of reinforced concrete structures is considered as one of significant factor. Domestic concrete specification offers a procedure to evaluate deflection using effective moment of inertia at cracked section, which has been known as Branson's equation in ACI. Branson's equation was derived from statistical analysis of maximum deflection of flexural members, but is somewhat weak in no reflection of bond characteristics between reinforced bars and concrete, such as tension stiffening effect. Therefore, present code creates difference from actual deflection. In this study, experiments about deflection of RC beams was completed to compare domestic standard and Eurocode 2, which calculates deflection considering tension stiffening effect. Four RC beams were built and tested, and initial modulus of elasticity and tensile strength of concrete used in the test was calculated by each design standard.

• Journal of the Korea Concrete Institute
• /
• v.23 no.4
• /
• pp.495-501
• /
• 2011

The load combinations in current KCI Design Code are determined with reference to those in ACI 318-05, which adopts the LRFD (load and resistance factor design) format. The load and resistance factors in LRFD format should be determined to meet the required levels of reliability index or probability of failure for various predetermined failure modes, which are also based on the statistical data reflecting locality and contemporary situation. However, the current KCI Design Code has been written utilizing foreign data, because of insufficiency in accrued data in Korea. This study considered the current safety levels of KCI Code based on published domestic data to evaluate appropriateness of the current KCI regulations. Based on the calibrated reliability index of the existing Code, the new resistance factors are suggested. The results presented in this paper can be considered as a basic research for establishment of unique design format for future Korean Codes.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.989-992
• /
• 2008

Recently, high-strength concrete has been frequently used for long-span bridges and high-rise buildings. Deflection of reinforced concrete structures is uncertain, so that many researchers have proposed various equations in order to predict deflection through experiments. Domestic concrete specification offers a procedure to evaluate deflection using effective moment of inertia which was proposed by Branson. However, it is inaccurate for high strength concrete compared to the method suggested in Eurocode 2 in that Eurocode 2 predicts deflection by using curvature integration of effective moment of inertia. In this study, experimental data about deflection of reinforced concrete beams were analyzed to compare domestic standard and Eurocode 2.

• Journal of the Korea Concrete Institute
• /
• v.23 no.4
• /
• pp.471-478
• /
• 2011

For a practical simplicity in designing of reinforced concrete structures, the indirect crack controlling method of limiting bar spacing is adopted in KCI structural design provisions. In addition, a direct method for evaluating crack width is also provided in the appendix of the code. But there may be some mismatched results between these two crack controlling methods. In this study, limit values of maximum bar spacing calculated from KCI provisions, KCI appendix, and Frosch's equation are examined as concrete strength, cross-section height, and concrete cover are varied, and the differences are analyzed. From the results, it becomes clear that the differences between maximum bar spacing calculated from KCI code text provisions and those from KCI code appendix provisions are too significant to be neglected. Therefore, rational crack models are suggested in order to get rid of the discrepancy between the direct and indirect control methods.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.383-386
• /
• 2011

본 논문에서는 철근콘크리트 구조물의 프레임부재 철근을 대상으로 배근 설계 및 철근 형상화 알고리즘을 구축하여 자동배근을 생성하는데 목적이 있다. 철근 콘크리트의 BIM 통합 설계 시스템은 철근 배근정보의 생성과 호환이 원활하지 않아 표준 정보 호환 체계가 구축되지 않은 실정이다. 기존 2차원 기반 프로세스에서는 철근 배근 설계에 있어 표준화된 기준에 따른 배근이 아닌 관행이나 일률적인 배근 지침에 따라 배근 상세를 정하고 있고, 2차원 배근 설계 결과만 제시하고 있어 상호 호환 가능한 철근 배근 정보데이터가 생성되지 않는다. 철근 콘크리트 구조에서의 철근 배근 정보를 생성하고 BIM 통합 구조 설계시스템에서의 정보 호환성을 확보하기 위해, 프레임부재 철근을 대상으로 구조 해석 데이터베이스와 통합 설계 플랫폼 간의 호환 시스템을 생성하고, 콘크리트학회 콘크리트 구조설계기준에 따른 배근 설계 및 철근 형상화 알고리즘을 구축하여 자동배근시스템(Integrated Reinforcement for Frame Members, 이하 IRFM)을 개발하는데 목적이 있다.

• Magazine of the Korea Concrete Institute
• /
• v.11 no.1
• /
• pp.4-11
• /
• 1999

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.301-304
• /
• 2010

이 논문에서는 콘크리트구조물의 성능설계를 위한 하중조합의 구성과 이의 신뢰도수준을 정하는 과정을 제시한다. 설계기준의 작성 및 적용에 관하여 논리적인 개념을 제시하고 있는 Eurocode 의 하중조합에 관한 기본 원칙을 살펴보고, 국내 및 미국의 콘크리트구조물의 설계에서 적용하고 있는 하중조합을 분석하여 본다. 구조물 설계에 관한 안전율의 결정에 있어서 널리 사용되고 있는 통계 및 신뢰도에 기반한 분석을 통하여, 현행 하중조합을 사용하고 재료별 저항계수를 적용하는 경우에 제공하게 되는 신뢰도 수준을 살펴본다. 철근콘크리트 보와 기둥의 예제를 이용하여 휨, 전단 및 축력에 관한 신뢰도 수준과 이에 영향을 미치는 설계변수들의 민감도분석을 수행한다.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.537-540
• /
• 2010

본 논문에서는 보의 주철근을 대상으로 건물정보모델링(BIM, Building Information Modeling)통합 설계 시스템 상에서 배근 설계 및 철근 형상화 알고리즘을 구축하여 자동배근 시스템(ARPM, Automatic Reinforcement Placing Module)을 개발하는데 목적이 있다. 구조분야에서의 BIM 프로세스는 정보호환체계를 구축하는 과정에 있으며, 철골 구조 프로세스의 경우 표준 호환 포맷을 이용하여 원활한 정보 호환 체계를 유지하고 있다. 하지만, 철근 콘크리트의 BIM 통합 설계 시스템은 철근 배근정보의 생성과 호환이 원활하지 않아 표준 정보 호환 체계가 구축되지 않은 실정이다. 기존 2차원 기반 프로세스에서는 철근 배근 설계에 있어 표준화된 기준에 따른 배근이 아닌 관행이나 일률적인 배근 지침에 따라 배근 상세를 정하고 있고, 2차원 배근 설계 결과만 제시하고 있어 상호 호환 가능한 철근 배근 정보데이터가 생성되지 않는다. 철근 콘크리트 구조에서의 철근 배근 정보를 생성하고 BIM 통합 구조 설계시스템에서의 정보 호환성을 확보하기 위해, 보의 주철근을 대상으로 구조 해석 데이터베이스와 통합 설계 플랫폼 간의 호환 시스템을 생성하고, 콘크리트학회 콘크리트 구조설계기준에 따른 배근 설계 및 철근 형상화 알고리즘을 구축하여 자동배근시스템(ARPM)을 개발하는데 목적이 있다.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.129-132
• /
• 2008

Coupled shear wall system is the primary seismic load resisting system of buildings. The coupling beam of these buildings must exhibit excellent ductility and energy dissipation capacity. To achieve better ductility and energy dissipation, the steel coupling beam embedded in the reinforced concrete walls is proposed. Performance of the steel coupling beam is mainly effected by embedment length. ACI equation and BS equation were examined with 23 previous test results. The statistical study uses the values of mean value, standard deviation, correlation coefficient, normal distribution curve, and error analysis. Through the analytical program, the evaluation of the 2 equations was established.