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  • Title/Summary/Keyword: 연성도 평가

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Ductility Evaluations of Internally Confined Hollow CFT Column (내부 구속 중공 CFT 교각의 연성도 평가)

  • Kim, Hyun-Jong;Youm, Enug-Jun;Han, Taek-Hee;Kang, Young-Jong
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.683-687
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    • 2007
  • Internally Confined Hollow-Concrete Filled Tube(ICH-CFT) column which has two tubes on both side of concrete, inner tube and outer tube perform great seismic abilities, ductility and absorption of energy, by the tubes and the hollow pmt. So this study does qualitative analysis about seismic capacities depending on parameters diameter of column, hollow ratio, thickness of tubes - by moment-curvature analysis.

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Execution Time Determination for Performance Improvement in Soft Real-Time Systems (연성 실시간 시스템에서 시스템 성능을 높이기 위한 수행시간 결정)

  • 정다니엘;이진호;홍성제
    • Proceedings of the Korean Information Science Society Conference
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    • 2001.04a
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    • pp.715-717
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    • 2001
  • 기존의 강성 실시간 시스템은 실시간 수행만 고려되어 있어. 실시간 시스템의 성능과 효율적인 시스템 활용과는 거리가 멀다. 따라서 효율적인 시스템 활용을 통하여 보다 많은 일을 수행할 수 있게 하는 연성 실시간 시스템을 사용하게 된다. 여기서는 보상값이라는 것을 사용하여 그것의 총합을 성능평가의 기준으로 사용하며, 보상값의 합을 최대로 할 수 있는 수행시간을 찾아 스케줄링에 사용하게끔 한다. 모의 실험을 통하여 알아낸 수행시간에 따른 보상값의 변화에 대한 경향을 이용하여 최대 보상값을 얻을 수 있는 수행시간을 찾고, 실험을 통하여 얻은 결과와 비교하였다.

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Seismic Performance of a Hollow Composite Column (강합성 중공 기둥의 내진 성능)

  • Han, Taek Hee;Kim, Jung Hun;Lim, Nam Hyoung;Kang, Young Jong
    • Journal of Korean Society of Steel Construction
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    • v.20 no.2
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    • pp.215-226
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    • 2008
  • A column test was performed for a hollow composite column to evaluate its seismic performance. The seismic performances of a hollow composite column and a reinforced concrete (RC) column were evaluated and compared by quasi-static tests. Lateral displacements and lateral loads of the column specimens were measured during tests. Ductilities, absorbed energy, equivalent damping ratios, and damage indices were calculated from the recorded data. From the test results, the hollow composite column showed a seismic performance superior to the column in terms of double moment capacity, ultimate energy, and energy absorption.

Development of Steering Control Algorithms for All-terrain Crane and Performance Verification Based on Real-time Co-simulation (전지형 크레인 조향제어 알고리즘 개발 및 연성해석 기반의 성능평가)

  • Seo, Jaho;Lee, Geun Ho;Oh, Kwangseok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.5
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    • pp.367-374
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    • 2017
  • The goal of this study was to develop control algorithms to improve the steering performance of a 120-ton all-terrain crane. To accomplish this, a hydraulic steering system for the crane was modeled using AMESim software, and a PID steering control algorithm was designed in the MATLAB/Simulink environment. The performance of the designed controller was verified through multiphysics co-simulations based on a real-time simulator.

Evaluation of Mechanical Property Variation of Epoxy Based Compliant Polymer Concretes Exposed to UV Light (에폭시 기반 연성 폴리머 콘크리트의 자외선 노출에 의한 기계적 물성평가)

  • Roh, In-Taek;Jung, Kyung-Chae;Chang, Seung-Hwan
    • Composites Research
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    • v.27 no.6
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    • pp.236-241
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    • 2014
  • This paper aims to evaluate material property variation of polymer concretes under ultra-violet exposure condition. The components and mixing ratio of the polymer composite specimens were determined by the previous research results. The equivalent UV exposure time was calculated with the consideration of the power of metal halide lamp and maximum 3 years were selected for the experiments. From the tests, it was found that the generated heat during UV exposure affected much the material properties of polymer concrete by means of post cure. As a result, the compressive strength increased and ductility factor decreased.

Seismic Evaluation of Steel Moment Frame Buildings based on Different Response Modification Factors and Fundamental Periods (반응수정계수와 주기의 영향에 대한 철골모멘트저항골조 건물의 내진성능평가)

  • Shin, Ji-Wook;Lee, Ki-Hak;Lee, Do-Hyung
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.5
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    • pp.47-56
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    • 2008
  • This study was performed to evaluate the effect of Response modification factors (R-factor) in 3-, 9- and 20- story steel Moment Resisting Frame (MRF) buildings. Each structure was designed using a R-factor of 8, as tabulated in the 2000 International Building Code provision (IBC 2000) and Korea Building Code (KBC) 2008. In order to evaluate the maximum and minimum performance expected for such structures, an upper bound and lower bound design were adopted for each model. Next, each analytical model was designed using different R-factors (8, 9, 10, 11, 12) and four different structural periods with the original fundamental period. For a detailed case study, a total of 150 analytical models were subjected to 20 ground motions representing a hazard level with a 2% probability of being exceeded in 50 years. In order to evaluate the performance of the structures, static push-over and non-linear time history analysis (NTHA) were performed, and displacement ductility demand was investigated to consider the ductility capacity of the structures. The results show that the dynamic behaviors for the 3- and 9-story buildings are relatively stable and conservative, while the 20-story buildings show a large displacement ductility demand due to dynamic instability factors. (e.g. P-delta effect and high mode effect)

A Comparative Study on News Service Models through Internet Portals: Softening News and Setting Agenda (포털 뉴스의 연성화와 의제설정의 탐색)

  • Jho, Whasun;Chang, Woo-Young;Oh, Sohyun
    • Informatization Policy
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    • v.19 no.3
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    • pp.19-35
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    • 2012
  • As Internet users increasingly consume news through the Internet, Internet portals face criticism that they are quickening the softening of public news and molding public opinions. Some portals have started to provide newscast services that directly connect the press, not grouping news sources on their own standards. This study aims to clarify how news grouping models and newscast models are different in terms of news softening and agenda setting. Specifically, authors conduct a content analysis on time-specific news content provided by top three portals-Naver, Daum, and Nate. By doing so, this study examines characteristics of news service models of Internet portals and their social and political implications. According to our study, the softening and tabloidization of portal news had not been improved even after adopting the newscast model. Therefore, portal journalism should be reorganized as a way to circulate healthy and qualified news content.

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Comparison of Modeling Methods of a Pile Foundation in Seismic Analysis of Bridge Piers (교각의 내진설계를 위한 말뚝기초의 모델링 기법 비교)

  • 김나엽;김성렬;전덕찬;김명모
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.6
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    • pp.25-32
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    • 2002
  • In the seismic designing of bridges, the pile foundation of bridge piers generally have been modeled to have a fixed end for its convenience and conservative designing. The fixed-end assumption, however, produces very conservative results in terms of the pier forces. Therefore, many other design methods are evolved to consider the flexibility of the pile foundation. In this study, the response spectrum analysis was performed for a bridge pier having a pile foundation. The shear force, moment, and displacement, which occurred at the pier column under an earthquake loading, were compared to analyze the effects of the modeling method, soil condition and the input earthquake response spectrum. In most cases, the fixed-end model gives larger design forces than flexible foundation models. However, when a long period earthquake is applied to the bridge pier on a soft clay foundation, it is found that the flexible foundation models give larger design forces than the fixed-end model. In the end, the reliability of several flexible foundation models was verified by comparing their results with those of a numerical analysis that considers the soil-structure interaction phenomenon in a rigorous manner.

An Examination of the Minimum Reinforcement Ratio for Reinforced Concrete Flexural Members (철근콘크리트 휨부재의 최소철근비에 대한 고찰)

  • Choi, Seung-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.6
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    • pp.35-43
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    • 2017
  • The minimum reinforcement ratio is an important design factor to prevent a brittle failure in RC flexural members. A minimum reinforcement ratio is presented by assuming an effective depth of cross-section and moment arm lever in CDC and KHBDC. In this study, it suggests that a rational method for minimum reinforcement ratio is calculated by material model and force equilibrium. As results, a minimum reinforcement ratio using a p-r curve in KHBDC is evaluated about 52~80% of recent design code's value and it induces an economical design. And also, a ductility capacity in case of placing this minimum reinforcement amount is evaluated about 89% of recent design code's value, but ductility in a member is 7 or more, so it has a sufficient ductility capacity. Therefore, it is judged that a minimum reinforcement ratio using p-r curve has a theoretical rationality, safety and economy in a flexural member design.

Confinement Effects of High Strength Reinforced Concrete Tied Columns (고강도 철근콘크리트 띠철근 기둥의 구속효과)

  • 신성우;한범석
    • Journal of the Korea Concrete Institute
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    • v.14 no.4
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    • pp.578-588
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    • 2002
  • An experimental study was conducted to investigate the effectiveness of transverse reinforcement in reinforced concrete tied columns subjected to monotonically increasing axial compression. Eighteen large-scale columns(260×260×1200 mm) were tested. Effects of main variables such as the concrete compressive strength, the tie configuration, the transverse reinforcement ratio, the tie spacing, and the spatting of the concrete cover were considered. High-strength concrete columns under concentric axial loads show extremely brittle behavior unless the columns are confined with transverse reinforcement that can provide sufficiently high lateral confinement pressure There is a consistent decrease in deformability of column specimen with increasing concrete strength. Test results were compared with the previous confinement model such as modified Kent-Park, Sheikh-Uzumeri, Mander, and Saatcioglu-Razvi model. The comparison indicates that many previous models for confined concrete overestimate or underestimate the ductility of confined concrete.