• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.609-618
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• 2009

This paper proposes a versatile formula which can be used to evaluate the fire resistant time of steel beams under various design conditions. Towards this end, the key parameters which affect the fire performance of steel beams were first determined through thermo-mechanical considerations, and classified into two groups: structural parameters and thermal parameters. Then the degree of influence of each parameter on the fire performance was investigated through a fully coupled thermo-mechanical analysis up to the occurrence of run-away deflection. The accuracy of the numerical model used was verified using an available full-scale fire test before conducting an extensive parametric analysis. Multiple linear regression analysis was performed to obtain the formula which can be used to predict the fire resistance time of steel beams under various design conditions. The statistical analysis showed that the proposed formula is very robust. The application of the formula in practical fire design under the current code was illustrated in detail. The economy and other advantages of the proposed formula were clearly shown.

• Journal of Korean Association for Spatial Structures
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• v.11 no.1
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• pp.57-66
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• 2011

For the lateral load resistance of a RC frame in a medium risk seismic zone, the strength of lower story beams and columns should be larger than those of the upper stories. However, the lateral loads can be accommodated by redistributing design beam moments vertically as well as horizontally so all beams end up with identical strengths. This paper looks at the impact of the vertical redistribution of beam moments to provide identical beam strength over as many floors as possible. Two-bay six-story RC frame was designed with and without vertical beam moment redistribution and its seismic performance were evaluated by using push-over limit analysis and by non-linear time history dynamic analysis. Analytical results show that with the use of vertical beam moment redistribution the increase in the ductility demand is similar to the proportion of moment redistribution applied, but this additional demand is below the ductility capacity of well detailed RC members.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.87-96
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• 2004

Recent test results on reduced beam section (RBS) steel moment connections showed that specimens with a bolted web tended to perform poorly due to premature brittle fracture of the beam flange at the weld access hole. The measured strain data appeared to imply that a higher incidence of base metal fracture in bolted-web specimens is related to, at least in part, the increased demand on the beam flanges due to the web bolt slippage and the actual load transfer mechanism which is completely different from that usually assumed in connection design. In this paper, the practice of providing web bolts uniformly along the beam depth was brought into question. A new seismic design procedure, which is more consistent with the actual load path identified from the analytical and experimental studies, was proposed together with improved connection details.

• Computational Structural Engineering
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• v.10 no.2
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• pp.233-242
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• 1997

The main purpose of this paper is to investigate the dynamic optimal design of continuous beams. The computer-aided optimization technique is used to obtain the near-optimal parameters of continuous beam. The computer program is developed to obtain the natural frequency parameters and the forced vibration responses to a transit point load for the continuous beam with variable support spacing, mass and stiffness. The model test data is in good agreement with the computer calculation, which serves to validate the mathematical analysis. The optimization function to describe the design efficiency is defined as a linear combination of four dimensionless span characteristics; the maximum dynamic stress; the stress difference between span segments; the rms deflection under the transit point load; and the total span mass. Studies of three span beams show that the beam with near-optimal parameters can improve design efficiency when compared to a uniform beam with even spacing of the same total span length.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.49-56
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• 1990

Todays, design of composite prestressed concrete beams is carried out by calculation of the prestressing force and its eccentricity assuming the sectional properties. However the characteristics of composite section made with a precast prestressed concrete beams and reinforced concrete slab is not reflected, so iteration method has been adopted. But its methed requires much time and labor. Accordingly, an improved design method will be presented. In this study, improved design method is proposed to design composite section directly without iterative calculation. Design examples according to the proposed design method are presented for easy application and verification of its reliability and authenticity. The results match well with the Hatcher's.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.6
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• pp.399-405
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• 2023

This study presents an optimal seismic design method based on genetic algorithms to induce beam-hinge collapse mechanisms in reinforced concrete moment frames. Two objective functions are used. The first minimizes the cost of the structure and the second maximizes the energy dissipation capacity of the structure. Constraints include strength conditions of columns and beams, minimum conditions for column-to-beam flexural strength ratio, and conditions for preventing plastic hinge occurrence of columns. Linear static analysis is performed to evaluate the strength of members, whereas nonlinear static analysis is carried out to evaluate energy dissipation capacity and occurrence of plastic hinges. The proposed method was applied to a four-story example structure, and it was confirmed that solutions for inducing a beam-hinge collapse mechanism are obtained. The value of the column-beam flexural strength ratio of the obtained design was found to be larger than the value suggested by existing seismic codes. A more robust strategy is needed to induce a beam-hinge collapse mode.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.84-87
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• 2009

본 논문에서는 최근 초고층 건축물에 많이 활용되어지는 기둥-가새 시스템인 다이아그리드 시스템을 활용하여 중저층 건축물에 적용가능성을 평가하였다. 본 시스템은 튜브구조의 형태로 횡력에 대한 저항력이 우수하며 중력하중과 황하중을 기초와 지반에 안전하게 하중을 전달한다. 다이아그리드는 경사기둥과 보를 반복적으로 삼각형 형태로 배치되어 중력하중을 받을 경우 수직부재는 압축력을 보는 인장력을 받게 된다. 경사기둥과 보를 연결하는 접합부는 H-형강으로 설계 시 제작이 복잡하고 외관이 좋지 않다. 하지만 원형강관을 사용 할 경우 복합하지 않은 형태로 설계가 가능하고 외관이 우수하기 때문에 외부에 노출이 가능해진다. 또한 원형강관은 개방형 단면 부재에 비해 압축좌굴과 비틀림에 대한 성능 등이 우수하여 구조적인 성능이 우수하다. 원형강관을 이용하여 다이아그리드 시스템이 고층 건축물 뿐만 아니라 중저층 건축물에도 적용 타당성을 검토하였으며 원형강관 접합부 설계는 한계상태설계법이 사용 된 KBC2008(안)을 이용하여 설계하였다.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.581-593
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• 2011

The underlying advantages of using thin-walled corrugatedwebs instead of plate girders with stiffeners are the elimination of instability problems associated with buckling of the thin-walled flat plate, and elimination of the need for transverse stiffeners, which alsoresults in economic advantages. This paper focuses on two aspects related to the structural design technique forsinusoidal corrugated web steel beams, and the optimum design of the beams using real-value genetic algorithms. The structural design process and design variables used in this optimization werecomposed with EN 1993-1-5, DASt-R015 standard and Pasternak et al. (2004), and the valid design capacity of shear buckling of the standards were compared. For the optimum structural design, the objective function, presented as the fullweight of the sinusoidal corrugated web beams, and the slenderness, member forces, and maximum deflection of the beam, were considered constraints. Finally, the simple beam under the uniform load was adopted as a numerical example, and the effective probability parameters of the genetic operators were considered to find the global minimum point.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.435-440
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• 2001

컴퓨터에 의한 음악의 처리가 점차 중요한 비중을 차지하여 감에 따라 음악의 신속, 정확한 입력이 크게 요구되고 있다. 서양의 음악을 악보화, 악보의 자동 인식에 관한 연구는 1960년대 후반부터 시작하여 지금은 다양한 악보를 인식하고, 악보를 미디로 변환하는 등 여러 부분에서 활용하고 있다. 그러나 우리의 전통음악을 우리 나라 악보인 정간보로 출력하는 시스템은 아직 존재하지 않는다. 그래서 본 논문에서는 세종 때부터 사용되었던 우리 나라 악보인 정간보에 대해 이해하고 컴퓨터를 통해 정간보를 입력할 수 있는 시스템을 설계 및 구현한다. 또한 사용자가 보다 쉽게 입력할 수 있도록 그래픽 유저 인터페이스(Graphic User Interface)형태로 제공하였다. 제안하는 정간보 이력 에디터 시스템 구현으로 우리 음악을 정간보로 체계적으로 관리할 수 있고 정간보 데이터 베이스(Data Base)가 구축이 되면 국악의 신속한 정보 검색이 가능하다. 향후 정간보 시스템이 체계화되면 우리 음악을 서양의 악보화로, 악보를 미디로 등의 변환이 가능하며 음악 애호가들은 약간 기억나는 악절을 기준으로 곡을 작곡할 수 있을 것이다.

• Journal of Korean Society of Steel Construction
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• v.15 no.4 s.65
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• pp.467-474
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• 2003

Composite action can be achieved by providing shear connectors between the steel top flange and concrete topping. Composite sections are stiffer than the sum of the individual stiffness of slab and beam. They can therefore carry heavier loads or similar loads with appreciably smaller deflection. They are also less prone to transient vibration. In this study, T-type Steel Composite beam (TSC-beam) was developed and tested. The test results of TSC beam were compared with the theoretical results based on composite actions.