• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.2
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• pp.37-46
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• 2000

본 논문에서는 부지특성을 고려한 설계지반운동의 산정방법을 연구하였으며 그 해석결과를 지반 구조물의 내진설계에 적용하는 방법을 제안하였다 지진응답 해석시 사용되는 설계응답스펙트럼과 설계시간 이력등의 입력운동의 통제점 위치가 지반구조물 내진설동 지층내 암반운동 그리고 노두운동을 사용하는 방법으로 나눌 수 있고 이에 따라 작용 설계지진운동이 변화하므로 지반구조물의 경계조건에 적합한 방법을 사용하여야 한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.5
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• pp.1-10
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• 2011

This paper proposes an efficient method for selecting ground motions with the mean response spectrum matching a target spectrum. Since former studies reported that the shape and amplitude of the response spectra can be treated independently for selecting ground motions, this study first selects ground motions such that the shape of their mean response spectrum matches that of the target spectrum, then scales the ground motions. To select the ground motions best matching the shape of the target response spectrum, the standard deviation of the difference between the target response spectrum and the mean response spectrum of the selected ground motions needs to be minimized. Unlike the existing procedure, the scaling factor can be computed without iteration. Based on the selection results of 7 ground motions from a library of 40 ground motions, the proposed method is verified as an accurate and efficient method.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.223-228
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• 2000

지진격리교량은 강진지역의 지반운동과 구조물의 거동에 근거한 내진설계 개념을 바탕으로 설계되었다. 그러나 지반운동의 특성과 구조물의 거동에 있어서 한반도와 같은 중약진 지역과 지각변동운동이 활발한 강진지역은 큰 차이를 보이고 있다. 따라서 중약진 지역의 내진설계에서는 지반운동의 특성이 반영되어야 할 필요가 있으며, 특히, 지진격리교량의 경우에는 교각의 연성 등 중약진 지역의 구조물의 거동특성이 반영되어야 한다. (중략)

• Journal of the Korean Geographical Society
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• v.42 no.3 s.120
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• pp.368-387
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• 2007

In order to explain geomorphological characteristics of the Korean Peninsula, it is necessary to understand the spatial distribution of tectonic movements and its causes. Even though geomorphological elements which might have been formed by tectonic movements(e.g. tilted overall landform, erosion surface, river terrace, marine terraces, etc.) have long been considered as main geomorphological research topics in Korea, the knowledge on the spatial distribution of tectonic movement is still limited. This research aims to identify the spatial distributions of tectonic movement via sequential analyses of Digital Elevation Model(DEM). This paper first developed a set of terrain analysis techniques derived from theoretical interrelationships between tectonic uplifts and landsurface denudation processes. The terrain analyses used in this research assume that elevations along major drainage basin divides might preserve original landsurfaces(psuedo-landsuface) that were formed by tectonic movement with relatively little influence by denudation processes. Psuedo-landsurfaces derived from a DEM show clear spatial distribution patterns with distinct directional alignments. Lines connecting psuedo-landsufaces in a certain direction are defined as psuedo-landsurface axes, which are again categorized into two groups: the first is uplift psuedo-landsurface axes that indicate the axis of landmass uplift; and the second is denudational psuedo-landsurface axes that cross step-shaped pusedo-landsurfaces formed via surface denudation. In total, 13 axes of pusedo-landsurface are identified in the Korean Peninsula, which show distinct direction, length, and relative uplift rate. Judging from the distribution of psudo-landsurfaces and their axes, it is concluded that the Korean Peninsula ran be divided into four tectonic regions, which are named as the Northern Tectonic Region, Center Tectonic Region, Southern Tectonic Region, and East Sea Tectonic Region, respectively. The Northern Tectonic Region had experienced a regional uplift centered at the Kaema plateau, and the rate of uplift gradually decreased toward southern, western and eastern directions. The Center Tectonic Region shows an arch-shaped uplift. Its uplift rate is the highest along the East Sea and the rate decreases towards the Yellow sea. The Southern Tectonic Region shows an asymmetric uplift centered a line connecting Dukyu and Jiri Mountains in the middle of the region. The eastern side of the Southern Regions shows higher uplift rate than that of the western side. The East Sea Tectonic Region includes south-eastern coastal area of the peninsula and Gilju-Myeongchun Jigudae, which shows relatively recent tectonic movements in Korea. Since this research visualizes the spatial heterogeneity of long-term tenonic movement in the Korean peninsula, this would provide valuable basic information on long-term and regional differences of geomorphological evolutionary processes and regional geomorphological differences of the Korean Peninsula.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.6
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• pp.35-47
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• 2003

Seismic ground motion can vary significantly over distances comparable to the length of a majority of highway bridges on multiple supports. This paper presents results of fragility analysis of two actual highway bridges under ground motion with spatial variation. Ground motion time histories are artificially generated with different amplitudes, phases, as well as frequency contents at different support locations. Monte Carlo simulation is performed to study dynamic responses of the bridges under these ground motions. The effect of spatial variation on the seismic response is systematically examined and the resulting fragility curves are compared with those under identical support ground motion. This study shows that ductility demands for the bridge columns can be underestimated if the bridge is analyzed using identical support ground motions rather than differential support ground motions. Fragility curves are developed as functions of different measures of ground motion intensity including peak ground acceleration(PGA), peak ground velocity(PGV), spectral acceleration(SA), spectral velocity(SV) and spectral intensity(SI). This study represents a first attempt to develop fragility curves under spatially varying ground motion and provides information useful for improvement of the current seismic design codes so as to account for the effects of spatial variation in the seismic design of long-span bridges.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.11-20
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• 2008

In probabilistic seismic analysis of nonlinear structural system, dynamic analysis is performed to obtain the distribution of the response estimate using input ground motion time histories which correspond to a given seismic hazard level. This study investigates the differences in the distribution of the responses and the failure probability according to input ground motion models. Two types of input ground motion models are considered: real earthquake records scaled to specified intensity level and artificial input ground motion fitted to design response spectrum. Simulation results fir a nonlinear SDOF system demonstrate that the spectrum matched input ground motion produces larger failure probability than those of scaled input ground motion due to biased responses. Such tendency is more remarkable in the site of soft soil conditions. Analysis results show that such difference of failure probability is due to the conservative estimation of design response spectrum in the range of long period of ground motion.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.137-144
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• 2019

For the structures near the seismogenic fault, the evaluation of seismic performance against near-fault ground motions is important as well as for design ground motions. In this study, characteristics of seismic behaviors and seismic performance of the pile-bent bridge constructed on the thick soft soil site with various weak soil layers were analyzed. The input ground motions were synthesized by the directivity pulse parameters for intra-plate regions. The ground motion acceleration histories of each layer were obtained by one-dimensional site response analysis. Each soil layer was modeled by equivalent linear springs, and multi-support excitations with different input ground motions at each soil spring were applied for nonlinear seismic analyses. The analysis result by the near-fault ground motions and ground motions matched to design spectra were compared. In case of the near fault ground motion input, the bridge behaved within the elastic range but the location of the maximum moment occurred was different from the result of design ground motion input.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.759-768
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• 2015

The ground motions of large dimensional structures such as long span bridges at different stations during an earthquake, are inevitably different, which is known as the ground motion spatial variation effect. There are many causes that may result in the spatial variability in seismic ground motion, e.g., the wave passage effect due to the different arrival times of waves at different locations; the loss of coherency due to seismic waves scattering in the heterogeneous medium of the ground; the site amplification effect owing to different local soil properties. In previous researches, the site amplification effects have not been considered or considered by a single-layered soil model only. In this study, however, the ground motion amplification and filtering effects are evaluated by multi-layered soil model. Spatially varying ground motion at the sites with different number of layers, depths, and soil characteristics are generated and the variation characteristics of ground motion time histories according to the correlation of coherency loss function and soil conditions are evaluated. For the bridge system composed of two unit bridges, seismic behavior characteristics are analyzed using the generated seismic waves as input ground motion. Especially, relative displacement due to coherency loss and site effect which can cause the unseating and pounding between girders are evaluated. As a result, considering the soil conditions of each site are always important and should not be neglected for an accurate structural response analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.45-54
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• 2006

The characteristics of the ground motion attenuation in Korea and Japan were estimated using the earthquake ground motions recorded at the equal distance observation stations by KMA, K-NET and KiK-net of Korea and Japan. The ground motion attenuation equations proposed for Korea and Japan were evaluated by comparing the predicted value fer the Fukuoka earthquake with the observed records. The predicted value from the attenuation equations shows good agreement with the observed records and each other. It can be concluded from this study that the ground motion attenuation equations developed for Japan can be used usefully for the prediction of a ground motion from far field earthquake more than 200 km and for the evaluation of the far field ground motion attenuation equations proposed fer Korea.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.111-111
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• 2015

한 지점의 수문 반응을 결정짓는 주요 인자 중의 하나는 유역의 형상과 유역 내 하계망 구조이다. 유역의 형상과 하계망 구조는 지질시간 규모에 걸쳐 서서히 형성된 것으로, 주로 지반운동, 암석 및 지질구조, 그리고 이에 대응하는 지표 침식 정도에 의해 결정된다. 따라서, 암석 및 지질구조가 균질하다면, 유역의 특성은 지반운동과 지표 침식에 의해 좌우될 것이다. 본 연구는 지반운동의 시간적인 분포가 서로 다른 조건일 때 유역 특성이 각각 어떠한지를 수치지형발달모형(numerical landscape evolution model)을 이용한 모의실험을 통해 이론적으로 탐색해보았다. 구체적으로 모의 기간 동안의 총 지반융기량은 동일하더라도, 융기율이 전 기간동안 동일한 조건, 융기율이 특정 시점에 집중되는 조건, 그리고 융기율이 높았던 때와 낮았던 때가 반복되는 조건 등 세가지 시나리오를 실험하였다. 각 조건에 대해, 유역 형상과 하계망 구조는 어떻게 형성되는지를 살펴본 것이다. 모의결과 유역의 형태와 하계망 구조는 총융기량보다는 융기율의 시간 분포에 결정적인 영향을 받는다는 것을 확인하였다. 또한, 융기율의 시간분포는 유역의 전반적인 경사(하천 종단의 요형도)와 충적하상 및 기반암하상 하도의 분포 등에 큰 영향을 주었다.