• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.190-195
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• 2001

In the present paper computational simulation of a concrete dam is performed to determine the effect of vertical ground motions on earthquake response of concrete dams. Cyclic and dynamic versions of the plastic-damage model proposed by Lee and Fenves are used to represent micro-crack development and crack opening/closing, which is important mechanism in nonlinear damage analysis of concrete structures subject to strong earthquake loading. The result shows that the vertical component of ground motion effects on final crack patterns and consequently, on displacement response.

• 지구물리와물리탐사
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• 제13권3호
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• pp.198-202
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• 2010

20세기에 한반도 및 인근에서 발생한 지진 중, 그 메카니즘이 Waveform Modelling 혹은 Moment Tensor Inversion 등 정량적인 방법에 의해 밝혀진 규모 4.5 이상의 18개 지진의 발생 원인을 분석하고 이들을 한반도 주변 동아시아 지역에서 발생하는 지진들과 비교 분석하였다. 한반도 및 인접지역에서 발생한 지진의 대부분은 주향이동 단층 운동에 의한 메카니즘에 다소의 역단층 운동이 첨가된 단층운동을 보여주고 단층작용을 일으킨 주응력 방향은 거의 수평한 동북 동-서남서 방향을 나타낸다. 이는 같은 판내 지역인 북동부 중국 지역과 일본 남서부의 주응력 방향과 매우 유사하고 동해 동부와는 상당한 차이를 보인다. 이는 한반도 및 그 주변에서 지진을 일으키는 주응력은 동쪽에서 유라시아판 밑으로 침강하는 태평양판의 영향뿐만 아니라 서남쪽에서 충돌하는 인도판의 영향도 상당히 작용하는 것으로 해석된다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.330-337
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• 2002

The objective of the earthquake resistant design of structures is to satisfy on the one side the minimization of damage requirement under earthquakes with high probability of occurrence during the design life and on the other side the no collapse requirement under the design seismic event with low probability of occurrence. The two requirements are satisfied with the minimum strength of substructure as well as the ductile failure mechanism presented in the codes. In this study seismic performance is evaluated with two bridges which have steel box superstructures and T type, II type piers as substructures. In order to satisfy the two requirements redesign of both substructures and steel bearings are carried out.

• 지구물리
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• 제9권3호
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• pp.249-262
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• 2006

The 29 May 2004 offshore Uljin, Korea earthquake was predominantly thrust-faulting at a depth of approximately 12 (±2) km. The mainshock attained the seismic moment of M0 =5.41 (±1.87)  1016 N m (Mw = 5.1). The focal mechanism indicates a subhorizontal P-axis trending 264° and plunging 2°. The orientation of P- and T-axis is consistent with the direction of absolute plate motion generally observed within the plates, hence the cause of the May 29 shock is the broad-scale stress pattern from the forces acting on the downgoing slab along the Japan trench and inhibiting forces balancing it. The 29 May 2004 earthquake occurred along a deep seated (~12 km), pre-existing feature that is expressed on the surface as the basement escarpment along the western and southern slopes of the Ulleung basin. The concentrated seismicity along this basement escarpment suggests that this feature may qualify as a seismic zone - the Ulleung basement escarpment seismic zone (UBESZ).

• Geomechanics and Engineering
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• 제4권1호
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• pp.39-53
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• 2012

Due to strong ground motion of earthquake, the material in the landslide can travel a significant distance from the source. A new landslide model called Multiplex Acceleration Model (MAM) has been proposed to interpret the mechanism of long run-out movement of this type of landslide, considering earthquake behaviors on slope and landslide materials. In previous study, this model was verified by a shaking table test. However, there is a scale limitation of shaking table test to investigate MAM in detail. Thus, numerical simulation was carried out in this study to validate MAM under full scale. A huge rock ejected and A truck threw upwards by seismic force during Wenchuan Earthquake (Ms. 8.0) was discussed based on the simulation results. The results indicate that collisions in P-phase of earthquake and trampoline effect are important behaviors to interpret the mechanism of long run-out and high velocity. The results show that MAM is acceptable and applicable.

• 지질공학
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• 제1권1호
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• pp.121-136
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• 1991

본 연구에서는 P파형의 초동극성 분포를 이용하여 홍성지진의 Focal Mechanism을 평가하였다. 비선형 전산처리과정을 이용하여 원지진진앙거리에서 관측된 9개의 P파형의 초동극성 분포와 주향, 경사 및 상반변위방향의 변화로부터 구한 Focal Mechanism과의 부합성을 조사하였다. 위의 과정을 이용하여 처리한 결과 주단층면의 주향 및 겅사는 약 247도 및 약 78도로서 홍성부근지역의 선구조와 잘 일치함을 보여주었다. 그러나, 주단층면의 상반변위 방향은 약 40도에서 약 160도 까지의 광범위한 값을 보여주었으나, 이는 관측점의 방위각 분포가 불충분하기 때문인 것으로 분석되었다. 위에서 결정된 Focal Mechanism이 의미하는 주응력 방향은 일본 트렌치를 따라서 태평양판이 유라시아판 아래로 Subduction할 때 가능한 지응력장가 상반되지 않음을 보여 주었다. 또한, 이러한 Focal Mechanism으로부터 원자력발전소나 핵폐기물 처리장 및 처분장 건설시, 부지고유응답 스펙트럼 및 강지진동 자료와 같은 내진설계기준을 위해 필요한 한반도의 지진지체구조 특성에 대한 정보를 얻을 수 있다.

• Earthquakes and Structures
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• 제3권5호
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• pp.749-766
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• 2012

Structural control through integration of passive damping devices within the building structure has been increasingly implemented internationally in the last years and has proven to be a most promising strategy for earthquake safety. In the present paper an alternative configuration of an innovative energy dissipation mechanism that consists of slender tension only bracing members with closed loop and a hysteretic damper is investigated in its dynamic behavior. The implementation of the adaptable dual control system, ADCS, in frame structures enables a dual function of the component members, leading to two practically uncoupled systems, i.e., the primary frame, responsible for the normal vertical and horizontal forces and the closed bracing-damper mechanism, for the earthquake forces and the necessary energy dissipation. Three representative international earthquake motions of differing frequency contents, duration and peak ground acceleration have been considered for the numerical verification of the effectiveness and properties of the SDOF systems with the proposed ADCS-configuration. The control mechanism may result in significant energy dissipation, when the geometrical and mechanical properties, i.e., stiffness and yield force of the integrated damper, are predefined. An optimum damper ratio, DR, defined as the ratio of the stiffness to the yield force of the hysteretic damper, is proposed to be used along with the stiffness factor of the damper's- to the primary frame's stiffness, in order for the control mechanism to achieve high energy dissipation and at the same time to prevent any increase of the system's maximum base shear and relative displacements. The results are summarized in a preliminary design methodology for ADCS.

• Earthquakes and Structures
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• 제5권3호
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• pp.343-357
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• 2013

On May 19, 2011 an earthquake struck Simav district of K$\ddot{u}$tahya which located west of Turkey. According to Disaster and Emergency Management Agency (DEMA), magnitude of this earthquake was $M_L$ = 5.7. In this earthquake 2 people lost their lives and considerably damages occurred in the city center and surrounding villages. Damaged structures in the earthquake area did not have adequate earthquake resistance since low quality materials, poor workmanship and improper selection of the structural system. In this study, reasons of damages and failure mechanism of reinforced concrete and masonry buildings were evaluated.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.348-355
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• 2000

The characteristics on non linear behavior and the failure mechanism of RC space frame structure serving railway under seismic action have been investigated by numerical analysis in time domain. The structure concerned is modeled in 3 dimensional extent and RC frame elements with fibers are employed. Fibers are characterized as RC one and PL one to distinguish different energy release after cracking. Due to deviation of mass center and stiffness center of entire structure the complex behavior under seismic action is shown. The excessive shear force is concentrated on the pier beside flexible one relatively, which leads to failure of bridge concerned.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.259-264
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• 1999

The magnetoelastic interaction between electrically conducting structures and magnetic fields is suggested to be used as a possible means for vibration suppression mechanism in structural control. Effectiveness of the active control mechanism is demonstrated by an experiment which is performed to examine the basic tenets of magnetically induced vibration and magnetoelastic damping of a cantilevered beam virating in the presence of magnetic fields Experimental results show that the feedback control scheme works effectively. Several strategies are suggested to improve the controllability using the magnetic damping.