• Title/Summary/Keyword: Seismic safety

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Analysis of Uniform Hazard Spectra for Metropolises in the Korean Peninsula (국내 주요 광역 도시에 대한 등재해도 스펙트럼 분석)

  • Rhee, Hyun-Me;Kim, Min Kyu;Sheen, Dong-Hoon;Choi, In-Kil
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.2
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    • pp.71-77
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    • 2013
  • The uniform hazard spectra for seven major cities in Korea, Seoul, Daejeon, Daegu, Busan, Gwangju, Ulsan, and Inchon are suggested. Probabilistic seismic hazard analyses were performed using the attenuation equations derived from seismology research in Korea since 2000 and the seismotectonic models selected by expert assessment. For the estimation of the uniform hazard spectra, the seismic hazard curves for several frequencies and PGAs were calculated by using the spectral attenuation equations. The seismic hazards (annual exceedance probability) calculated for the 7 metropolises ranged from about $1.4305{\times}0^{-4}/yr$ to $1.7523{\times}10^{-4}/yr$ and averaged out at about $1.5902{\times}10^{-4}/yr$ with a log standard deviation of about 0.085 at 0.2 g. The uniform hazard spectra with recurrence intervals of 500, 1000, and 2500 years estimated by using the calculated mean seismic hazard on the frequencies presented peak values at 10.0 Hz, and the log standard deviations of the difference between metropolises ranged from about 0.013 to 0.209. In view of the insignificant difference between the estimated uniform hazard spectra obtained for the considered metropolises, the mean uniform hazard spectrum was estimated. This mean uniform hazard spectrum is expected to be used as input seismic response spectrum for rock sites in Korea.

A Case Study on the Seismic Hazard Classification of Domestic Drinking Water Earthfill Dams Using Zero Seismic Failure Probability Curve (지진파괴확률 영곡선 활용 국내 식수전용 흙댐의 지진 위험도 분류 사례 연구)

  • Ha, Ik-soo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.26 no.4
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    • pp.173-180
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    • 2022
  • Most of the drinking water dams managed by the local governments in Korea are earthfill dams, and these dams have almost no geotechnical property information necessary for seismic performance evaluation. Nevertheless, in the rough planning stage for improving seismic safety for these dams, it is necessary to classify their relative seismic hazard against earthquakes and conduct an additional ground investigation. The zero seismic failure probability curve is a curve suggested in this study in which the probability of failure due to an earthquake becomes '0' regardless of the geotechnical properties of the earthfill dam. By examining the method and procedure for calculating failure probability due to an earthquake suggested in previous researches, the zero seismic failure probability curves for an earthquake in 1,000-year and 2,400-year return periods in Korea were presented in the form of a hyperbola on the plane of the dam height versus freeboard ratio (ratio of freeboard to dam height), respectively. The distribution characteristics of the dam height and the freeboard ratio of 81 Korean earthfill dams were presented. The two proposed zero seismic failure probability curves are shown on the plane of the dam height versus freeboard ratio, and the relative seismic hazard of 81 dams can be classified into three groups using these curves as boundaries. This study presented the method of classifying the relative seismic hazard and the classification result.

Nonlinear Seismic Analysis of a Three-dimensional Unsymmetrical Reinforced Concrete Structure (3차원 비대칭 철근콘크리트 구조물의 비선형 지진응답해석)

  • Lim, Hyun-Kyu;Lee, Young-Geun;Kang, Jun Won;Chi, Ho-Seok;Cho, Ho-Hyun;Kim, Moon-Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.5
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    • pp.429-436
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    • 2014
  • This paper presents the seismic performance of a geometrically unsymmetrical reinforced concrete building considering torsional effect and material nonlinearity of concrete and steel. The reinforced concrete building is a structure for seismic performance evaluation in the SMART-2013 international benchmark program. Nonlinear constitutive models for concrete and steel were constructed, and their numerical performance was demonstrated by various local tests. Modal analysis showed that the first three natural frequencies and mode shapes were close to the experimental results from the SMART-2013 program. In the time history analysis for low-intensity seismic loadings, displacement and acceleration responses at sampling points were similar to the experimental results. In the end, nonlinear time history analysis was conducted for Northridge earthquake to predict the behavior of the reinforced concrete structure under high-intensity seismic loadings.

Design of a Seismic Isolation Table for both indoor and outdoor Electrical Communication Equipment (전기통신설비를 위한 옥내외 겸용 면진테이블 설계)

  • Lee, Chun-Se;Ahn, Hyeong-Joon;Lee, Taek-Won;Son, In-Chul
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.10a
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    • pp.472-472
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    • 2009
  • The safety of cultural properties, medical treatment and electrical communication equipments in a building was hardly considered against the earthquake induced vibration, while the integrity of the building structure has been taken into account through the resistant earthquake design. This paper presents design of a seismic isolation table for both indoor and outdoor electrical communication equipment. First of all, artificial earthquake waves compatible with floor and ground response spectra for electrical communication equipments are generated using previously recorded seismic waves. Two kinds of one-degree-of-freedom seismic isolation table systems: spring-linear damper and spring-friction damper systems are considered and their responses to artificial earthquake waves are simulated. Design parameter study for two seismic isolation tables are performed through simulations and a seismic isolation table for both indoor and outdoor electrical communication equipment is designed considering the simulation results.

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Seismic Fragility Analysis of Base Isolated Liquid Storage Tank (면진 유체 저장 탱크의 지진취약도 분석)

  • Ahn, Sung-Moon;Choi, In-Kil;Choun, Young-Sun
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2005.03a
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    • pp.453-460
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    • 2005
  • In this study, the seismic fragility analysis of a base isolated condensate storage tank installed in the nuclear power plant. The condensate storage tank is safety related structure in a nuclear power plant. The failure of this tank affect significantly to the core damage frequency of the nuclear power plants. The seismic analysis of the liquid storage tank was performed by the simple calculation method and the dynamic time storage analysis method. The convective and impulsive fluid mass is modeled as added masses proposed by several researchers. To evaluate the effectiveness of the isolation system, the comparison of HCLPF and core damage frequencies in non-isolated and isolated cases are carried out. It can be found from the results that the seismic isolation system increases the seismic capacity of a condensate storage tank and decreases the core damage frequency significantly.

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Study on Selection of Nuclear Seismic Fragile Equipment and Its Enhancement of Seismic Performance (주요기기 내진성능 상향을 위한 설비보강 및 취약부 도출연구)

  • Son, Jung-Dae;Koo, Gyeong-Hoi
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.14 no.2
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    • pp.16-23
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    • 2018
  • In order to investigate the ways to enhance the seismic performance of APR1400 seismic fragile equipment by direct design changes, four equipment such as Reactor Vessel Support, Integrated Head Assembly, Remote Shutdown Console, and Pressurizer are reviewed using information of the main dimensions, seismic stress evaluation results, design FRS, etc. in this paper. In addition to the direct reinforcement of equipments, the feasibility of seismic isolation for the safety related cabinet is also investigated and the actual adaption plan of a commercial spring-damper system is briefly reviewed.

Dynamic Experiment to Evaluate Response Characteristics of High-Rise Buildings on Period Characteristics of Seismic Waves (지진파 주기특성에 따른 고층건축물의 응답특성 평가를 위한 동적실험)

  • Oh, Sang-Hoon;Kim, Ju-Chan
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.10
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    • pp.127-133
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    • 2019
  • Damage to high-rise buildings caused by earthquakes is less frequency due to small distribution of high-rise buildings and low transmissibility of seismic motion to high-rise buildings. However, demand for high-rise buildings is increasing for development of construction technology and efficient land use. In addition, if high-rise buildings are constructed on soft ground such as landfill, transmissibility of seismic motion due to long-periodization of seismic waves is likely to increase. Thus, with development of technology, buildings are required to expand range of seismic design such as safety for long-period seismic waves. Therefore, in this study, dynamic experiments were performed to evaluate response characteristics of high-rise buildings according to period characteristics of seismicwaves and time history analysis was performed to verify them.

Seismic Performance Evaluation of Valve Support using Simplified FE Model (단순 해석 모델을 이용한 밸브지지대 내진 성능 평가)

  • Kim, Sang-Young;Keum, Dong Yeop;Kim, Hyoung Eun;Kim, Dae Jin;Kim, Jun Ho;Hong, Seong Kyeong;Choi, Won Mok;Seok, Chang Sung
    • Journal of the Korean Society of Safety
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    • v.32 no.1
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    • pp.60-65
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    • 2017
  • In this study, a simplified FE model for evaluating seismic performance of valve support was suggested and an apparatus for a real structure testing was developed. The seismic performances of three different types of valve supports were evaluated by the real structure testing. By comparing the results between the real structure testing and FEA using the simplified FE model, it was verified that the suggested simplified FE model can be utilized for comparative evaluation of seismic performance of valve supports.

The Seismic Analysis of 72.5kV Gas Insulated Switchgear(GIS) (72.5kV 가스절연차단기(Gas Insulated Switchgear)의 내진해석)

  • Lee, S.H.;Cho, S.S.;Kang, S.M.;Ahn, K.Y.;Bang, J.D.;Min, K.S.;Choi, J.W.;Yoon, S.S.
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.762-764
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    • 2001
  • In order to evaluate the structural safety from an earthquake, the seismic analysis of large structures such as GIS in electric power substations and equipments for nuclear power plant has been carried out because the seismic qualification by experiment is very expensive. This paper presents the seismic analysis of the 72.5kV GIS produced by LGIS. The finite element model of the GIS is developed and analyzed using ANSYS. The model consists of beam elements for the enclosures and mass elements for the conductors and the mechanisms. Using the transient analysis under seismic load, the structural safety is verified.

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