• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.174-181
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• 2002

The paper presents an effective analytical method for SSI systems which can have separation or sliding at the soil-structure interface. The method is based on a hybrid approach which combines a linear SSI code KIESSI-2D in frequency domain with a commercial finite element package ANSYS to obtain nonlinear dynamic responses in time domain. The method is applied to a 2-D underground box structure which experiences separation and sliding at the soil-structure interface. Material nonlinearity of the concrete structure is also included in the analysis. Effects of the interface conditions are examined and some critical factors affecting the seismic performance of underground structures are identified.

• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.75-81
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• 2000

본 연구에서는 진동대 시험을 실시하여 지진동에 대한 일반 안벽 구조물과 내진 보강된 안벽 구조물의 동적거동을 분석하고 내진보강기법의 성능을 평가하였다. 진동대 시험은 기초지반이 조밀한 경우와 느슨한 경우, 자갈 뒤채움재를 설치한 경우 그리고 내진대책공법으로 경량재 치환공법과 모래다짐말뚝 공법을 적용한 경우 등 총 5가지 시험단면에 대하여 실시하였다. 과잉간극수압, 가속도 반응 그리고 지반의 변형양상을 분석한 결과, 기초지반과 뒤채움 지반의 연약화가 안벽 구조물의 동적거동에 큰 영향을 미치며, 경량재 치환공법과 모래다짐말뚝공법이 안벽 구조물의 내진성능을 향상시키는에 효과적인 것으로 나타났다.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.257-260
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• 2006

Coupled shear walls consist of two or more in-plane walls inter-connected with coupling beams. In order to effectively resist seismic loads, coupling beams must be sufficiently stiff, strong and posses a stable load-deflection hysteretic response. Much of requirements to the civil and building structures have recently been changed in accordance with the social and economic progress. Ductility of high performance fiber reinforced cementitious composites(HPFRCCs), which exhibit strain hardening and multiple crackling characteristics under the uniaxial tensile stress is drastically improved. This paper provides background for design guidelines that include a design model to calculate the shear strength of pseudo strain hardening cementitious composite steel coupling beam.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.74-80
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• 2013

This study describes structural reliability analysis of actively-controlled structure for which random vibration analysis is incorporated into the first-order reliability method (FORM) framework. The existing approaches perform the reliability analysis based on the RMS response, whereas the proposed study uses the peak response for the reliability analysis. Therefore, the proposed approach provides us a meaningful performance measure of the active control system, i.e., realistic failure probability. In addition, it can deal with the uncertainties in the system parameters as well as the excitations in single-loop reliability analysis, whereas the conventional random vibration analysis requires double-loop reliability analysis; one is for the system parameters and the other is for stochastic excitations. The effectiveness of the proposed approach is demonstrated through a numerical example where the proposed approach shows fast and accurate reliability (or inversely failure probability) assessment results of the dynamical active control system against random seismic excitations in the presence of parametric uncertainties of the dynamical structural system.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.145-146
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• 2017

최근 세계적으로 많은 지진이 발생하고 있으며 기상이변으로 인한 자연재해로 인해 주요 시설물들의 안전성에 관한 관심이 증가하고 있는 추세이다. 특히 비구조 요소의 경우 구조 요소보다 건설 초기 투자비용이 높아 지진이 발생하였을 때 많은 피해가 발생할 가능성이 있으며 비구조 요소의 파괴는 심각한 2차피해로 발전 될 수 있으므로 내진안전성 평가는 반드시 이루어져야 한다고 볼 수 있다. 따라서 본 연구에서는 압착식 조인트의 접촉을 고려한 수계소화설비 파이프라인의 내진성능 평가를 위한 비선형 유한요소 모델을 구축하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.276-281
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• 2000

As the construction of the high-rise building increases worldwide, the effort has been exerted to improve the safety and serviceability if the structure against various types of external dynamic loads such as wind load, seismic load, etc. The mass damper, defined as dynamic absorber in mechanical engineering is known one of the effective methods to control the vibration of flexible large structures. The hybrid mass damper, HMD is known as the most appropriate type of the mass dampers. In this paper, the control force was designed for HMD by numerical simulations and the performance of HMD to control the flexible vibration of the steel tower induced by sinusoidal force excitation was evaluated, also TMD was designed for a 1-DOF lumped mass model.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.281-288
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• 1999

This paper studied the efficiency of retrofitting of reinforced concrete structure which was not designed to endure an earthquake. The earthquake in Kobe Japan showed that there was a great possibility of having an earthquake even in big city and the damages were concentrated on mid or low story buildings which were not considered to be protected from an earthquake, . This experiment used reinforced concrete structure which restrained side-by-side displacement to test durability against an earthquake. This study deals with the structural performance of reinforced concrete frame structures strengthened with steel materials.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.208-215
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• 2003

지진하중에 대한 구조물의 동적 거동과 성능을 예측 평가하기 위하여 실험적 방법들이 흔히 사용되고 있으나, 실험장비의 제약과 구조물의 규모 등으로 대부분 축소모형실험에 의존하고 있다. 그러나 일반적인 상사법칙(similitude law)은 탄성범위에서 유도된 것으로 지진거동과 같은 비탄성 거동을 예측하는 경우에는 한계가 있다. 또한 탄성범위 내에서도 크기효과(size offset)가 발생하므로 축소모형의 실험결과를 원형 구조물에 직접 적용하는 것은 많은주의가 필요하다. 본 연구에서는 원형 구조물(prototype)과 축소모형(scaled model)을 모두 실험 대상으로 하여 실제 축소모형만을 실험하여 원형 구조물의 거동을 예측하는 경우의 문제점을 확인하고 그 해결방법을 모색하고자 한다. 실제로 축소모형실험에서는 원형 구조물의 경계조건을 정확히 재현하기 어려우며, 실험모형의 제작과정과 실험과정에서의 모든오차가강성의 변화로 반영되어 나타난다. 따라서 본 연구에서는 기하학적 상사율과 변화된 강성비(stiffness ratio)를 함께 고려하여 고유진동수의 오차를 보정하고 비탄성 거동중에도 직접적인 실험결과의 비교가 가능한 상사법칙을 제안하였다. 더불어 제안된 상사법칙을 적용한 유사동적실험 (pseudodynamic test)을 수행하여 실험오차보정(experimental error compensation)효과를 검증하였다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.172-179
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• 2003

In the performance based seismic design method such as the capacity spectrum method, it is required to estimate precisely strength, deformability and energy dissipation of the member. However it merely depends on empirical equations which are not exact in the estimation of energy dissipation capacity. It is same to the generously used computer programs for nonlinear analysis such as DRAIN-2DX. On the other hand, simple equations for evaluating energy dissipation were developed in a recent study, In this paper, based on the evaluation method, a new cyclic behavior model for a flexure-dominated RC member is proposed. Although this model is simplified, it can accurately reflect the variation of energy dissipation capacity with design parameters. Using this model, a program for the nonlinear static/dynamic analysis of RC moment frame structures is also developed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.205-212
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• 2003

To evaluate the seismic performance of multistory building structures use an equivalent SDOF model. This paper presents a method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through perform nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. The hysteresis rules to be used an equivalent SDOF model is obtained from the pushover analysis. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. The representative lateral displacement of a moment resisting reinforced concrete frames is close to the height of the first modal participation vector $_1$$\beta$｛$_1$u｝=1. It can be found that the hysteresis rule of an equivalent SDOF model have influence on the time history response. Therefore, it is necessary for selecting hysteresis rules to consider hysteresis characteristics of a moment resisting reinforced concrete frames.