• 한국지진공학회논문집
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• 제24권6호
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• pp.293-303
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• 2020

Seismic fragility was assessed for non-seismic reinforced concrete shear walls in Korean high-rise apartment buildings in order to implement an earthquake damage prediction system. Seismic hazard was defined with an earthquake scenario, in which ground motion intensity was varied with respect to prescribed seismic center distances given an earthquake magnitude. Ground motion response spectra were computed using Korean ground motion attenuation equations to match accelerograms. Seismic fragility functions were developed using nonlinear static and dynamic analysis for comparison. Differences in seismic fragility between damage state criteria including inter-story drifts and the performance of individual structural members were investigated. The analyzed building had an exceptionally long period for the fundamental mode in the longitudinal direction and corresponding contribution of higher modes because of a prominently insufficient wall quantity in such direction. The results showed that nonlinear static analyses based on a single mode tend to underestimate structural damage. Moreover, detailed assessments of structural members are recommended for seismic fragility assessment of a relatively low performance level such as collapse prevention. On the other hand, inter-story drift is a more appropriate criterion for a relatively high performance level such as immediate occupancy.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1132-1137
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• 2010

There are execute of new laws about prevent of earthquake diaster in nation because of some increments of big earthquake occurence frequency. Now develope new composit plate by ductile fiber with strong mechanic materials, which compose of strengthening systems for the underground structures subject to forced displacements. This study is to focus to develop the retrofitting system for the cut and cuver tunnels built without earthquake type load scenario, so that it can provide the safety of existing urban subway system against earthquakes.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.223-230
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• 1999

The seismic damage assessment to the postulated earthquake is attempted for the buildings in the model district of Seoul City. The capacity spectrum method is employed in which the vulnerability functions are expressed as functions of the spectral displacement. the database of the building stock is constructed and managed using Geographic Information System software. The model district is selected to represent the typical structural and residential characteristics of Seoul City The structural properties were collected from the design documents. The field inspections were carried out to find out the current status of the building. They are classified into 11 structural types. The fragility curves in HazUS are employed, The ground motions from the postulated earthquakes are simulated using the Boor's methods, The surface soil in the district is classified into 3 profiles using the depth as the parameter. The one-dimensional wave propagation method is used to calculate he filtered ground motion through surface soil layer. The average spectrum of this sample time histories is used as the demand curves. The calculated results are expressed in maps using GIS software ArcView 3.0a

• 한국지형학회지
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• 제25권1호
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• pp.97-113
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• 2018

Low-frequency geological natural disaster events such as Pohang earthquake have been occurred. As a results, there's a growing recognition on the importance of education and training for low frequency geological disasters in Korea. In spite of many years of scientific researches on volcanic disaster prevention and preparedness on Baekdusan volcano, the results do not provide the proper scenario for the training for volcanic ash event. Fall 3D volcanic ash diffusion model was run based on wind field data for the last five year, assuming Aso Mountain's explosion with volcanic explosion index 5 for seventy two hours. The management criteria values for proper actions in the previous studies were applied to make a scenario for thirteen groups of the disaster response teams such as train transportation, water supply, electrical facilities and human health. The models on the relationship between education and training for disaster prevention and response were suggested to fulfill the scientific and practical training at local level.

• 한국지리정보학회지
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• 제10권1호
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• pp.47-59
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• 2007

미국의 FEMA와 NIBS에서 개발한 HAZUS-MH는 GIS를 기반시스템으로 하는 자연재해 전후의 피해정도를 평가 및 분석하는 재해정보시스템이다. 본 연구에서는 HAZUS-MH를 한반도의 일부지역에 시범적으로 적용하고, 그 운영에서의 효율성 및 문제점을 제시한다. 한반도 지진관련 연구자료 및 역사지진자료를 토대로 경상남북도를 적용대상지역으로 선정하였다. 연구지역에서 발생한 지진 중 인명피해가 있었던 서기 779년 경주에서 발생한 규모 6.7의 지진을 선택하여, 이 지진이 2000년도에 재발생하였다는 가정 하에 HAZUS를 적용하였다. 이 시스템을 적용하여 연구지역의 지진재해를 예측할 때 USGS에서 제공하는 ShakeMap의 지진동자료를 이용하였다. 이러한 연구를 통하여 미국의 HAZUS가 한반도에도 적용가능하다는 것을 알 수 있었으며, 한반도 전 지역에서 발생하는 모든 자연재해에 대하여 HAZUS를 적용한다면 우리나라의 자연재해에 의한 피해를 예측하고 대응하는데 효율적으로 이용될 수 있을 것으로 기대된다.

• Structural Engineering and Mechanics
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• 제66권1호
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• pp.75-84
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• 2018

This study presents the reliability-based analysis of nonlinear structures using the analytical fragility curves excited by random earthquake loads. The stochastic method of ground motion simulation is combined with the random vibration theory to compute structural failure probability. The formulation of structural failure probability using random vibration theory, based on only the frequency information of the excitation, provides an important basis for structural analysis in places where there is a lack of sufficient recorded ground motions. The importance of frequency content of ground motions on probability of structural failure is studied for different levels of the nonlinear behavior of structures. The set of simulated ground motion for this study is based on the results of probabilistic seismic hazard analysis. It is demonstrated that the scenario events identified by the seismic risk differ from those obtained by the disaggregation of seismic hazard. The validity of the presented procedure is evaluated by Monte-Carlo simulation.

• Earthquakes and Structures
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• 제15권1호
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• pp.29-44
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• 2018

A ground-motion prediction equation (GMPE) for the Korean Peninsula, especially for South Korea, is developed based on synthetic ground motions generated using a ground motion model derived from instrumental records from 11 recent earthquakes of $M_L$>4.5 in Korea, including the Gyeongju earthquake of Sept. 12. 2016 ($M_L$5.8). PSAs of one standard deviation from the developed GMPE with $M_W$ 6.5 at hypocentral distances of 15 km and 25 km are compared to the design spectrum (soil condition, $S_B$) of the Korean Building Code 2016 (KBC), indicating that: (1) PSAs at short periods around 0.2 sec can be 1.5 times larger than the corresponding KBC PSA, and (2) SD's at periods longer than 2 sec do not exceed 8 cm. Although this comparison of the design spectrum with those of the GMPE developed herein intends to identify the characteristics of the scenario earthquake in a lower-seismicity region such as South Korea, it does not mean that the current design spectrum should be modified accordingly. To develop a design spectrum compatible with the Korean Peninsula, more systematic research using probabilistic seismic hazard analysis is necessary in the future.

• Geomechanics and Engineering
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• 제13권5호
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• pp.775-791
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• 2017

Surface wave techniques are widely used as non-invasive method for geotechnical site characterization. Field surface wave data are collected and analyzed using different processing techniques to generate the dispersion curves, which are further used to extract the shear wave velocity profile by inverse problem solution. Characteristics of a dispersion curve depend on the subsurface layering information of a vertically heterogeneous medium. Sometimes soft layer can be found between two stiff layers in the vertically heterogeneous media, and it can affect the wave propagation dramatically. Now most of the surface wave techniques use the fundamental mode Rayleigh wave propagation during the inversion, but this may not be the actual scenario when a soft layer is present in a vertically layered medium. This paper presents a detailed and comprehensive study using finite element method to examine the effect of soft layers which sometimes get trapped between two high velocity layers. Determination of the presence of a soft layer is quite important for proper mechanical characterization of a soil deposit. Present analysis shows that the thickness and position of the trapped soft layer highly influence the dispersion of Rayleigh waves while the higher modes also contribute in the resulting wave propagation.

• Earthquakes and Structures
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• 제16권4호
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• pp.437-453
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• 2019

This study investigates a new optimal placement method for viscous dampers between structures in order to prevent pounding of adjacent structures with different dynamic characteristics under earthquake effects. A relative displacement spectrum is developed in two single degree of freedom system to reveal the critical period ratios for the most risky scenario of collision using El Centro earthquake record (NS). Three different types of viscous damper design, which are classical, stair and X-diagonal model, are considered to prevent pounding on two adjacent building models. The objective function is minimized under the upper and lower limits of the damping coefficient of the damper and a target modal damping ratio. A new algorithm including time history analyses and numerical optimization methods is proposed to find the optimal dampers placement. The proposed design method is tested on two 12-storey adjacent building models. The effects of the type of damper placement on structural models, the critical period ratios of adjacent structures, the permissible relative displacement limit, the mode behavior and the upper limit of damper are investigated in detail. The results of the analyzes show that the proposed method can be used as an effective means of finding the optimum amount and location of the dampers and eliminating the risk of pounding.

• 한국지반신소재학회논문집
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• 제12권4호
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• pp.133-141
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• 2013

본 연구에서는 시울지역 내 분포하고 있는 15개 지역의 문화재 주변지반에 대하여 표면파탐사를 바탕으로 하는 지반조사결과를 이용하여 수치해석 기반의 3차원 내진해석을 수행하였으며, 해석결과를 기반으로 지반변위를 분석하였다. 해석결과, 지반의 변위는 (구)공업전습소 본관이 최대 약 9.7mm로 나타났다. 이와 같이 변위가 작게 나타난 원인은 문화재가 위치한 지역의 토층이 매우 단단하기 때문으로 표면파 탐사를 통해서 분석된 지반가속도를 비교해 보아도 하부에 매우 단단한 암층이 존재하는 것으로 확인되었다. 그러나 낙성대 삼층석탑에 있어서, 지반 자체의 변위는 다른 지역과 유사하게 나타났으나 화강암으로 구성된 석탑은 상부에서 최대 30mm의 변위를 나타냈다. 이는 낙성대 삼층석탑을 지지지하는 지반의 경우 지진파에 대한 상호 보완을 할 수 있는 구조, 즉 지반반력으로 인한 감쇠효과가 나타나기 때문에 지반의 변위 자체는 작게 해석되었으나 상부 구조물의 경우에는 지진파가 작용하였을 때 응력해방에 기인하여 변위가 가장 많이 발생한 것으로 판단된다.