• Steel and Composite Structures
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• v.4 no.3
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• pp.227-246
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• 2004

This paper presents a moment-curvature method that accounts for the strength deterioration of steel at elevated temperature in estimating the response of steel beams exposed to fire. A modification to the EC4 method is proposed for a better estimation of the temperature distribution in the steel beam supporting a concrete slab. The accuracy of the proposed method is verified by comparing the results with established test results and the nonlinear finite element analysis results. The beam failure criterion based on a maximum strain of 0.02 is proposed to assess the limiting temperature as compared to the traditional criteria that rely on deflection limit or deflection rate. Extensive studies carried out on steel beams with various span lengths, load ratios, beam sizes and loading types show that the proposed failure criterion gives consistent results when compared to nonlinear finite element results.

• Journal of Industrial Technology
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• v.16
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• pp.139-145
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• 1996

Many of the bridge systems, including the girders and cross-beams, and concrete decks behave as the special othotropic plates. A method of calculating the natural frequency corresponding to the first mode of vibration of beam and tower structures with irregular cross-sections was developed and reported by D. H. Kim in 1974. Since 1989, The author has extended this method to Vibration analysis of two dimensional problems including composite laminates, and has reported at several conferenes. Frequently, the bridge floor panels are supported by girders and cross beams. Such panels as well as some of the building floor panels can be assumed as simple supported special orthotropic plates. In this paper, the result of application of simple method of vibration analysis developed by D. H. Kim, to the simply supported sandwich panels with point Mass/Masses is presented.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.3
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• pp.23-34
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• 2000

반복하중을 지지하는 4개의 2/3 크리 접합부 실험을 통하여 콘크리트 기둥 및 강재 보로 구성된 골조에 대한 외부 모멘트 접합부의 이력거동을 조사하였다. 주요 실험 변수는 접합부에 배치된 후프근의 수, 콘크리트만의 전단강도 발현응ㄹ 유도한 접합부 상세, 강재 보 플랜지 상, 하부에 스터드 형태의 전단키를 사용한 상세 등이다. 실험 시 관측된 균열양상, 파괴형상 및 다양한 계측결과에 근거하여 접합부 상세에 따른 각 시험체의 거동이 자세히 기술되었으며, 항복 후 보유강도, 강성저하 정도 및 에너지 소산능력 등이 분석되었다. 실험결과에 의하면, 이들 중 패널 및 인접 기둥 영역에 각각 2개의 후프근을 갖는 시험체 (CF3) 가 가장 우수한 이력응답을 나타냈으며, 이러한 형태의 접합부 상헤는 우리나와 같은 약진 지역에 적합할 것으로 판단되었다.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.869-877
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• 2011

In order to manufacture precision parts which are used for IT and BT Industry by machining, users need higher speed & precision machining center. So, for development of this kind of machine, we designed gantry type machining center which is piling of 3 axes on one moving body and the 2-axis rotary table is fixed on the base. It is applied linear motor that is instead of ball-screw and servo-motor combination and 50,000 rpm high-speed spindle. Composite material structure called mineral casting or resin concrete is applied also. This paper presents design technology and evaluated results of high speed and precision machining center.

• Computers and Concrete
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• v.21 no.5
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• pp.569-582
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• 2018

In this study, nonlinear vibration and stability of a polymeric pipe reinforced by single-walled carbon naotubes (SWCNTs) conveying fluid-nanoparticles mixture flow is investigated. The Characteristics of the equivalent composite are determined using Mori-Tanaka model considering agglomeration effects. The surrounding elastic medium is simulated by orthotropic visco-Pasternak medium. Employing nonlinear strains-displacements, stress-strain energy method the governing equations were derived using Hamilton's principal. Differential quadrature method (DQM) is used for obtaining the frequency and critical fluid velocity. The influence of volume percent of SWCNTs, agglomeration, geometrical parameters of pipe, viscoelastic foundation and fluid velocity are shown on the frequency and critical fluid velocity of pipe. Results showed the increasing volume percent of SWCNTs leads to higher frequency and critical fluid velocity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.337-338
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• 2012

As a rahmen structure, the connection among columns of Green frame is divided into three types such as sleeve, coupler (column pre and post installation), and bolt. The bolt type consists of six types according to steel frame shape and each type has different constructability, safety, structural performance, cost, and quality. Therefore, the analysis of comparison among the types is necessary. The objective of this study is to analyze the characteristics according to the shape of six bolt types to select the appropriate connection of Green frame. The results of this study can be used as a basic study for indentifying the characteristics of steel frame on site applying bolt type connection of Green frame. In addition, this study can be applicable to compare and analyze the performance and constructability of six bolt types in detail.

• KIEAE Journal
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• v.3 no.4
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• pp.15-22
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• 2003

Open housing is an emerging, new concept in housing development that combines demand-orientation with environment-friendliness. Its methodology, however, has not been analyzed in a systematic way. In this study, the features of planning method in open housing were analyzed to systematize types of the planning method. The existing planning methods of open housing was reviewed and they can be classified into three approaches such as pattern, module and organization planning. Given three approaches, the existing planning methods of open housing can be sub-classified as follows; free and patterned planning by patterns, modular and non-modular planning by modules, and hierarchical and non-hierarchial planning by organizations. The framework for the typological analysis was made based on the classification and a composite typological system was drawn from the analysis of the existing planning features. The suggested classification of features in open housing is expected to contribute to the clear definition of characteristics on open housing to provide a basis for the concrete realization method, to analyzing problems with the existing planning methods and to providing their solutions.

• Proceeding of KASS Symposium
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• 2005.05a
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• pp.205-212
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• 2005

In order for utilization of the concrete filled tubular, It Is necessary to scrutinize interfacial characteristics between heterogeneous materials, and be performed to various analytical studies on the composite structure. In this paper, this analytic study is carried on using ABAQUS Package/ Version 5.8-1, and the variables aye the relations between the coefficient of friction and the contact pressure for analyzing the behavior on the contact surface, through modifying the analytic methods and improving some problems. It is used to subdivided analytical methods in this research which categorize into four regions and can obtain closer effect for the bond behavior. Four categories compose of the chemical bond and mechanical bond legions replaced the full-interaction before yielding, and the pure friction and moving-down regions after yielding.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.48-51
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• 2008

Shear connector is the element which resist in the horizontal shear force between steel and concrete of composite members and the stud bolt is often used because of its constructional convenience and serviceability. Although the push-out test is the most common method to evaluate shear slip behaviour, it is suitable for only room temperature conditions. In this study, we investigated about shear force, temperature distribution and slip displacement of shear connector in high temperature through the modified push-out test with electronic furnace invented for steel part heating.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.198-199
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• 2016

기존 콘크리트 구조물의 내력 및 처짐에 저항하기 위하여 섬유시트를 사용한 복합섬유 패널 보강재를 셋 앵커를 이용하여 콘크리트 구조물과 일체화시키는 공법을 개발하였다.. 본 연구에서 적용된 실험 결과에 의하면 엥커+에폭시 보강 I 시험체가 기준시험체에 비하여 최대하중이 3.13배 증가, 동일 앵커갯수인 앵커보강시험체에 비하여 1.14배 증가하여으며, 에폭시보강시험체는 기준시험체에 비하여 최대하중이 3.08배 증가하였으나 계면에서 섬유박리로 인한 취성 파괴가 발생하였다.