• Transactions on Electrical and Electronic Materials
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• 제2권1호
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• pp.7-11
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• 2001

We measured the electron transport coefficients, the electron drift velocity, W, and the longitudinal diffusion coefficient, $D_{L}$, over the E/N range from 0.03 to 100 Td and gas pressure range from 0.133 to 122 kPa in the 0.526% and 5.05% $C_{3}F_{8}$-Ar mixtures by the double shutter drift tube with variable drift distance. And we calculated these electron transport coefficients by using multi-term approximation of Boltzmann equation analysis. We determined the electron collision cross sections set for $C_{3}F_{8}$ molecule by the comparison of measurement and calculation. Our special attention in the present study was focused upon the inelastic collision cross sections of the $C_{3}F_{8}$ molecule.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.578-581
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• 2007

In this study, the seismic control performance of energy dissipation devices installed in a shear all-frame structure is investigated through nonlinear time history analysis of a 12-story building. Inelastic shear walls are modeled using the multiple vertical line element model (MVLEM) and inelastic columns and girders were modeled using fiber beam elements. For a seismic load increased by 38% compared to the design load, the seismic control performance was analyzed based on the results of a nonlinear time history analysis in terms of the inter-story drift, the story shear and the flexural strain. Friction type dampers was found to performs best if they are installed in the form of a brace adjacent to the shear wall with the friction force of 15 % of the maximum story shear force induced in the original building structure without dampers.

• Structural Engineering and Mechanics
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• 제23권4호
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• pp.369-386
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• 2006

The influence of reinforcement buckling on the flexural response of reinforced concrete members is studied. The stress-strain response of compression reinforcement is determined computationally using a large-strain finite element model for bars of varied diameter, length, and initial eccentricity, and a mathematical expression is fitted to the simulation results. This relationship is used to represent the response of bars in compression in a moment-curvature analysis of a reinforced concrete cross section. The compression bar may carry more or less force than a tension bar at a corresponding strain, depending on the relative influence of Poisson effects and bar slenderness. Several cross-section analyses indicate that, for the distances between stirrups prescribed in modern concrete codes, the influence of inelastic buckling of the longitudinal reinforcement on the monotonic moment capacity is very small and can be neglected in many circumstances.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.273-278
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• 2000

These days, the number of residential-commercial buildings and apartments with pilotis is increasing. Generally, these buildings have a special structural called as Hybrid Structures consisting of upper-Walls and lower-Frames. However, this structures have some problems to be solved for the application of the regulation on the earthquake-resistant design and analysis techniques. Especially, in the case of irregular formal structures, engineers have to consider both the equivalent static analysis and the dynamic analysis. Thus, it is recommended to analyze those to inelastic region for economical reasons. In this paper, the method of modeling preceding the inelastic dynamic analysis using the DRAIN-2DX is presented to compare with those from MIDAS GENw program.

• Steel and Composite Structures
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• 제1권3호
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• pp.341-354
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• 2001

This paper provides a state-of-the-art review on advanced analysis models for investigating the load-displacement and ultimate load behaviour of steel and composite frames subjected to static gravity and lateral loads. Various inelastic analysis models for steel and composite members are reviewed. Composite beams under positive and negative moments are analysed using a moment-curvature relationship which captures the effects of concrete cracking and steel yielding along the members length. Beam-to-column connections are modeled using rotational spring. Building core walls are modeled using thin-walled element. Finally, the nonlinear behaviour of a complete multi-storey building frame consisting of a centre core-wall and the perimeter frames for lateral-load resistance is investigated. The performance of the total building system is evaluated in term of its serviceability and ultimate limit states.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.475-480
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• 1997

Highrise concrete buildings are very sensitive to cumulative and differential shortening of their vertical element such as wall and columns. Inelastic deformation due to creep and shrinkage consist of various factors and load history af actual building is very complicated. Therefore, for the accurate prediction and compensation of axial shortening, special efforts in design and construction phase are required to ensure long-term serviceability and strength requirement. In this paper, axial shortening estimation and compensation procedure is presented, which utilized experimentally determined concrete properties and preliminary load history and computerized approach, in case of Plaza Rakyat office tower, 79-story reinforced concrete building under construction in Malaysia.

• 한국강구조학회 논문집
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• 제8권4호통권29호
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• pp.77-84
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• 1996

The structural members under seismic loading actually show inelastic behavior, so the inelastic responses should be calculated for the seismic design of structures or estimating the structural damage level. Although direct time history analysis may calculate the exact dynamic nonlinear responses for given ground motions, this approach involves a high computational cost and long period. Therefore, it should be developed the approach to estimate nonlinear responses for the practical purpose. The artificial earthquake accelerograms were generated to obtain the smoothed responses spectra, and the samples of generated accelerogram for each seismic event was used to examine average nonlinear response spectra. The stabilized response spectra for each earthquake event was used to evaluate the effects of various yield strength ratios, damping values and nonlinear hysteretic models. The approach, which can simply predict the nonlinear seismic responses of structures, was shown in this study.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.406-413
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• 2001

The energy dissipation or damage prevention capability of structure can be greatly enhanced by employing hysteretic dampers. According to recent studies by the authors, the ratio of hysteretic damper stiffness to structural story stiffness has been identified as one of the most important parameters for characterizing the performance of this damper In this study the method for determining appropriate properties of hysteretic dampers to satisfy the given performance objectives is developed based on the concept of capacity spectrum method. The comparison with the results from inelastic time history analysis proves that the hysteretic dampers designed from the proposed method restrains the displacement well within the target displacement.

• 한국강구조학회 논문집
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• 제18권2호
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• pp.225-237
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• 2006

김 등(2005a, b)의 연구를 확장시켜 시스템 좌굴 고유치해석법을 이용한 유효좌굴길이 산정법과 2차 탄성해석기법을 이용한 2차모멘트를 이용하여 축력과 휨모멘트를 받는 라멘구조의 보-기둥부재에 대한 개선된 좌굴설계법을 제안한다. 이를 위하여 먼저 국내도로교설계기준, AISC-LRFD, SRC의 각 설계기준에 제시된 내하력 기준식을 이용하여 응력-변형율 관계를 유도하고, 이를 이용한 탄성 및 비탄성 좌굴 고유치해석을 이용한 유효좌굴길이 산정법을 고찰한다. 또한 라멘구조에 대하여 AISC-LRFD에서 제시하고 있는 좌굴 안정성 검토식과 본 연구에서 제시하는 안정성 검토식을 해석예제를 통하여 비교, 검토를 행한다.

• Earthquakes and Structures
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• 제15권6호
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• pp.667-685
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• 2018

In eccentrically braced steel frames (EBFs), the links are fuse members which enter inelastic phase before other structure members and dissipate the seismic energy. Based on the force-based seismic design method, damages and plastic deformations are limited to the links, and the main structure members are required tremendous sizes to ensure elastic with limited or no damage. Force-based seismic design method is very common and is found in most design codes, it is unable to determine the inelastic response of the structure and the damages of the members. Nowadays, methods of seismic design are emphasizing more on performance-based seismic design concept to have a more realistic assessment of the inelastic response of the structure. Links use ordinary steel Q345 (the nominal yielding strength $f_y{\geq}345MPa$) while other members use high strength steel (Q460 $f_y{\geq}460MPa$ or Q690 $f_y{\geq}690MPa$) in eccentrically braced frames with high strength steel combination (HSS-EBFs). The application of high strength steels brings out many advantages, including higher safety ensured by higher strength in elastic state, better economy which results from the smaller member size and structural weight as well as the corresponding welding work, and most importantly, the application of high strength steel in seismic fortification zone, which is helpful to popularize the extensive use of high strength steel. In order to comparison seismic behavior between HSS-EBFs and ordinary EBFs, on the basis of experimental study, four structures with 5, 10, 15 and 20 stories were designed by PBSD method for HSS-EBFs and ordinary EBFs. Nonlinear static and dynamic analysis is applied to all designs. The loading capacity, lateral stiffness, ductility and story drifts and failure mode under rare earthquake of the designs are compared. Analyses results indicated that HSS-EBFs have similar loading capacity with ordinary EBFs while the lateral stiffness and ductility of HSS-EBFs is lower than that of EBFs. HSS-EBFs and ordinary EBFs designed by PBSD method have the similar failure mode and story drift distribution under rare earthquake, the steel weight of HSS-EBFs is 10%-15% lower than ordinary EBFs resulting in good economic efficiency.