• Title/Summary/Keyword: regions of low-to-moderate seismicity

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Seismic Response Analysis and Performance Evaluation of Wind-Designed Concentrically Braced Steel Highrise Buildings under Moderate Seismicity (중진대의 지진환경하에서 내풍설계된 초고층 철골조 중심가새골조의 지진응답해석 및 내진성능평가)

  • Lee, Cheol-Ho;Kim, Seon-Woong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.9 no.1 s.41
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    • pp.33-42
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    • 2005
  • Even in moderate to low seismic regions like Korean peninsular where wind loading usually governs the structural design of a tall builidng, the probable structural impact of the 500-year design basis earthquake (DBE) or the 2400-year maximum credible earthquake (MCE) on the selected structural system should be considered at least in finalizing the design. In this study, seismic performance evaluation was conducted for concentrically braced steel highrise buildings that were only designed for wind by following the assumed domestic design practice. It was found that wind-designed concentrically braced steel highrise buildings possess significantly increased elastic seimsic capacity due to the system overstrength resulting from the wind-serviceability criterion and the width-to-thickness ratio limits on steel members. The strength demand-to-strength capacity study based on the response spectrum analysis revealed that, due to the system overstrength factors mentioned above, wind-designed concentrically braced steel highrise buildings having a slenderness ratio of larger than six can withstand elastically even the maximum credible earthquake at the performance level of immediate occupancy.

Safety of Ductility Demand Based Seismic Design for Circular RC Bridge Columns (원형 철근콘크리트 교각에 대한 연성도 내진설계법의 안전성)

  • Lee, Jae-Hoon;Hwang, Jung-Kil;Choi, Jin-Ho
    • Journal of the Korea Concrete Institute
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    • v.20 no.2
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    • pp.193-202
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    • 2008
  • Seismic design for bridge columns of the current Korea Highway Bridge Design Specifications which adopt full ductility design concept results in reinforcement congestion problems in construction site. It is due to large amount of confining steel is required even for small ductility demand which is a normal case in low and moderate seismicity regions like Korean peninsular. Therefore a new seismic design method based on limited ductility concept was proposed, which is called ductility demand based design method. It uses the new confining steel design equation considering ductility demand and aspect ratio of the column as well as material strength. The purpose of this study is to verify safety of the ductility demand based design method by the confining steel design equation. Eighty nine circular column test results are selected and investigated in terms of ductility factor and its safety. The safety factor for the circular column test results ranges between 1.11 and 3.98, and the average is 1.90. In this paper, the basic concept and detailed design procedure of the ductility demand based design method are also introduced as well as the investigation of the safety with respect to the major variables in confining steel design.