• 한국지구과학회지
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• 제28권7호
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• pp.871-877
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• 2007

최근 발생한 오대산지진(2007년 1월 20일)으로부터 관측된 지반진동 파형을 이용하여 응답스펙트럼을 분석하였으며, 결과를 국내 원자력 관련 구조물의 내진설계 기준과 비교하였다. 연구에 이용된 지반진동 개수는 수평성분 및 수직성분 각각 21개 및 8개이다. 지반진동을 이용하여 주파수별 지반응답을 구하고 정규화 분석 및 통계적 분석을 하였다. 본 연구결과를 국내 원자력시설물의 내진기준에 해당하는 Reg. Guide 1.60과 비교한 결과 특히 약 10 Hz 이상의 고주파수 영역에서 수직 및 수평 성분 모두 MPOSD스펙트럼이 Reg. Guide 1.60보다 높은 값을 보여 주었다. 따라서 향후 국내 지진활동 실정에 적합한 내진설계를 위해 수직 및 수평 성분 모두 10Hz 이상의 고주파수 대역에서 응답스펙트럼 값을 심각하게 고려할 필요가 있다.

• 한국소음진동공학회논문집
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• 제24권5호
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• pp.390-398
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• 2014

Heavy-weight floor impact noise is directly related to the impact source and floor vibration property. Dynamic properties of the standard floating floor that is used in Korea was investigated using accelerance, acceleration energy spectral density(ESD), and structural modal test. In the standard floating floor, natural frequency was decreased by the finishing mortar mass and the damping ratio was increased. Bang-machine force spectrum acting on the concrete slab can be calculated using inverse system analysis. Impact force acting on concrete slab is changed by interaction of finishing mortar and resilient material. The amplitude of the bang-machine force spectrum was amplified in low frequency range(below 100 Hz), and over 100 Hz was decreased. Changed force spectrum influence to the response of structure vibration, so the heavy-weight floor impact noise level was changed.

• 대한토목학회논문집
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• 제40권5호
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• pp.509-520
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• 2020

현행 내진설계 일반(KDS 17 10 00)에 따르면 내진설계 시 사용하는 입력지진파에 대한 기준이 명확히 제시되어 있고 실지진파에 대해서는 표준설계응답스펙트럼에 맞추어 보정하도록하고 있으나, 실지진파 선택에 따른 영향이 사전에 평가되지 않아 지진파 선택 시 어려움이 있다. 본 연구에서는 국내외에서 발생한 실지진파에 대하여 국내 설계기준이 제시하는 표준설계응답스펙트럼에 부합하도록 보정한 후, 수치해석을 통하여 필댐의 침하량 변화를 평가하였다. 그 결과 댐 하단에 작용하는 자유장 가속도의 영향보다 댐 마루에서의 최대가속도, 댐제체를 통한 증폭 특성등 제체 상부의 거동이 침하량에 가장 큰 영향을 미치는 것으로 나타났다. 또한, 동일한 표준설계응답스펙트럼으로 보정한 입력지진파일지라도 초기 실지진파와 댐 제체에서의 증폭 특성에 따라 침하량이 달리 평가될 수 있음을 확인하였다.

• 한국지진공학회논문집
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• 제7권2호
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• pp.39-48
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• 2003

반응수정계수의 핵심구성요소인 연성계수에 대하여 통계적 분석을 수행하였다. 연성계수의 체계적인 산정을 위하여 총 1,860개의 지진기록을 수집하였다. 수집된 지진기록을 지반 전단파의 평균속도에 따라 4가지로 분류하고, 탄소성 이력거동을 가지는 단자유도 구조물에 대하여 비탄성 스펙트럼을 작성하였다. 작성된 비탄성 스펙트럼으로부터 연성계수를 구하고, 변위연성비, 토질조건, 규모 및 진앙거리가 연성계수에 미지는 영향을 분석하였다. 토질 조건별로 평균연성계수를 구하고, 산정된 연성계수의 산포도를 검토하기 위하여 변동계수를 산정하였다.

• Earthquakes and Structures
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• 제26권5호
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• pp.327-336
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• 2024

Evaluation of tunnel performance in seismic-prone areas demands efficient means of estimating performance at different hazard levels. The present study introduces an innovative push-over analysis approach which employs the standard earthquake spectrum to simulate the performance of a tunnel. The numerical simulation has taken into account the lining and surrounding rock to calculate the rock-tunnel interaction subjected to a static push-over displacement regime. Elastic perfectly plastic models for the lining and hardening strain rock medium were used to portray the development of plastic hinges, nonlinear deformation, and performance of the tunnel structure. Separately using a computational algorithm, the non-linear response spectrum was approximated from the average shear strain of the rock model. A NATM tunnel in Turkey was chosen for parametric study. A seismic performance curve and two performance thresholds are introduced that are based on the proposed nonlinear seismic static loading approach and the formation of plastic hinges. The tunnel model was also subjected to a harmonic excitation with a smooth response spectrum and different amplitudes in the fully-dynamic phase to assess the accuracy of the approach. The parametric study investigated the effects of the lining stiffness and capacity and soil stiffness on the seismic performance of the tunnel.

• 한국지진공학회논문집
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• 제24권3호
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• pp.123-128
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• 2020

Analysis of the 2016 Gyeongju earthquake and the 2017 Pohang earthquake showed the characteristics of a typical high-frequency earthquake with many high-frequency components, short time strong motion duration, and large peak ground acceleration relative to the magnitude of the earthquake. Domestic nuclear power plants were designed and evaluated based on NRC's Regulatory Guide 1.60 design response spectrum, which had a great deal of energy in the low-frequency range. Therefore, nuclear power plants should carry out seismic verification and seismic performance evaluation of systems, structures, and components by reflecting the domestic characteristics of earthquakes. In this study, high-frequency amplification factors that can be used for seismic verification and seismic performance evaluation of nuclear power plant systems, structures, and equipment were analyzed. In order to analyze the high-frequency amplification factor, five sets of seismic time history were generated, which were matched with the uniform hazard response spectrum to reflect the characteristics of domestic earthquake motion. The nuclear power plant was subjected to seismic analysis for the construction of the Korean standard nuclear power plant, OPR1000, which is a reactor building, an auxiliary building assembly, a component cooling water heat exchanger building, and an essential service water building. Based on the results of the seismic analysis, a high-frequency amplification factor was derived upon the calculation of the floor response spectrum of the important locations of nuclear power plants. The high-frequency amplification factor can be effectively used for the seismic verification and seismic performance evaluation of electric equipment which are sensitive to high-frequency earthquakes.

• 센서학회지
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• 제22권3호
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• pp.223-226
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• 2013

We designed a single polyethylene bonner sphere with several thermo-luminescence dosimeters (TLD), for measurement of neutron energy spectrum. For the separation of the neutron dosage in the neutron-gamma mixed field, we used 21 ea TLD-600s and TLD-700s, respectively. Because, TLD-600 is sensitive to neutron and gamma rays, and, TLD-700 is sensitive only to gamma-rays, we could determine the each dose by neutron and gamma rays. The neutron response function of the bonner sphere with TLDs was calculated by MCNPX (ver. 2.5.0) Monte Carlo simulation in the energy range from $10^{-1}$ to 20 MeV. For the Cf-252 standard neutron source in KRISS, we could estimate the neutron energy spectrum by unfolding method using the response function.

• 한국지진공학회논문집
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• 제18권5호
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• pp.231-240
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• 2014

This study reviews the status and validity of seismic design criteria (SDC) for major facilities in Korea, which are composed of performance criteria and technical standard. Various facilities with different seismic design response spectra are analyzed to identify their seismic performance and necessity of eventual retrofit. The results are used to derive improvement directions of SDC. It is also concluded that the technical standard should be improved after the revision of the performance criteria.

• Earthquakes and Structures
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• 제12권4호
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• pp.389-395
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• 2017

In this paper a simple approach is presented for spectral matching of ground motions utilizing the wavelet transform and a recently developed metaheuristic optimization technique. For this purpose, wavelet transform is used to decompose the original ground motions to several levels, where each level covers a special range of frequency, and then each level is multiplied by a variable. Subsequently, the vibrating particles system (VPS) algorithm is employed to calculate the variables such that the error between the response and target spectra is minimized. The application of the proposed method is illustrated through modifying 12 sets of ground motions. The results achieved by this method demonstrate its capability in solving the problem. The outcomes of the VPS algorithm are compared to those of the standard colliding bodies optimization (CBO) to illustrate the importance of the enhancement of the algorithm.

• 한국소음진동공학회논문집
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• 제24권6호
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• pp.483-492
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• 2014

Uncomfortable feelings of occupants by indoor floor impact noise in a residential building are not accurately represented by the floor impact noise from a standard impact source. It is due to the characteristics of standard impact sources, which are different from the impact forces produced by occupants. It varies significantly by impact source, and it is not easy to be replicated for testing. As a result, the indoor floor impact noise under different acoustic conditions cannot be directly compared. Using frequency response function(FRF), which represents the input-output relationships of a dynamic system, it is possible to examine the characteristics of the system. Especially, FRF can predict the response of a linear dynamic system subjected to various excitation. To determine the relationship between impact force and the corresponding response of dynamic system in residential building, the acceleration response of a concrete slab and the floor impact noise in the living room, produced by bang-machine and rubber-ball excitation, were measured. The test results are compared to the estimates based on FRF and impact force spectrum.