• 한국산업융합학회 논문집
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• 제12권4호
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• pp.187-192
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• 2009

This study is performing a seismic analysis on the steel frames structure with dampers and analyzing the dynamic behavior in order to examine their efficiency and study the optimum dampers position to the seismic design steel structure. To improve the ability against an earthquake, this study performed the time history analysis. Controling an earthquake is the way to minimize the damage of the steel structure by dissipating input energy generated by an earthquake.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.505-512
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• 2003

As large structures such as highrise buildings and cable-stayed bridges become lighter and more flexible, the necessity of structural control for reducing excessive displacement and acceleration due to seismic excitation is increased. As a means to minimize seismic damages, various base isolation systems are adopted or considered for adoption. In this study, the seismic performance of M dampers are studied and compared with that of the NZ system as a base isolation system As the control algorithm of the MR damper, the clipped-optimal control(applied LQR method) is employed. A five-story building is modeled and the seismic performance of the two systems subjected to three different earthquakes is compared. The results show that the M damper system can provide superior protection than the NZ system for a wide range of ground motions.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.495-502
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• 2006

Seismic performance of semi-active fuzzy control algorithm to operate MR dampers for coupling adjacent building is investigated in this paper. In the proposed semi-active control technique, the fuzzy logic is used as a method to adjust input voltage to MR damper. In order to validate control performance of proposed technique, the seismic performance of the semi-active fuzzy control system is compared with that of passive control system where the input voltage to MR damper is set to display maximum damping force. The simulated results show that the semi-active fuzzy control technique effectively regulates the trade-off existing between seismic responses of two buildings subject to various earthquake excitations.

• Structural Engineering and Mechanics
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• 제88권3호
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• pp.209-220
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• 2023

This study investigates the effectiveness of tuned mass dampers (TMDs) in controlling vibrations in low-rise reinforced concrete buildings. It examines both linear and nonlinear behaviors of concrete structures subjected to strong ground motions from the PEER database. The research follows the ASCE 7-16 provisions to model structural nonlinearity. Additionally, the study explores the effect of varying TMD mass ratios on the performance of these systems in real-world conditions. The findings emphasize the importance of accounting for structural nonlinearity in low-rise buildings, highlighting its significant influence on the controlled response under severe seismic excitations. The study suggests including nonlinear analysis in seismic design practices and recommends customizing TMD designs to optimize vibration control. These recommendations have practical implications for enhancing the safety and effectiveness of seismic design practices for low-rise buildings.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.810-813
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• 2004

A study on the dynamic response of single-storey steel frames equipped with a rotational friction damper is presented. Extensive testing was carried out for assessing the friction pad material, damper unit performance and foaled model frame response to lateral harmonics excitation. Numerical simulations based on non-linear time history analysis were used to evaluate the seismic behaviour of steel frames with rotational frictional damper. It Is demonstrated that using discrete friction dampers of proper parameters to link steel frame can reduce dynamic response significantly.

• Smart Structures and Systems
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• 제24권3호
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• pp.345-360
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• 2019

The shear keys are set in a seismic isolation system to resist the long-term service loadings, and are cut off to isolate the earthquakes. This paper investigated the influence of shear keys on the seismic performance of a vertical spring-viscous damper-concave Coulomb friction isolation system by an incremental dynamic analysis (IDA) and a performance-based assessment. Results show that the cutting off process of shear keys should be simulated in a numerical analysis to accurately predict the seismic responses of isolation system. Ignoring the cutting off process of shear keys usually leads to untrue seismic responses in a numerical analysis, and many of them are unsafe for the design of isolated structure. And those errors will be increased by increasing the cutting off force of shear keys and decreasing the spring constant of shear keys, especially under a feeble earthquake. The viscous damping action postpones the cutting off time of shear keys during earthquakes, and reduces the seismic isolation efficiency. However, this point can be improved by increasing the spring constant of shear keys.

• Steel and Composite Structures
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• 제51권2호
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• pp.173-183
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• 2024

This study investigates a new seismic retrofit system that utilizes rotational friction dampers and axial springs. The retrofit system involves a steel frame with rotational friction dampers (RFD) at beam-column joints and linear springs at the corners, providing energy dissipation and self-centering capabilities to existing structures. The axial spring acts as a self-centering mechanism that eliminates residual deformations, while the friction damper mitigates seismic damage. To evaluate the seismic performance of the proposed retrofit system, a series of cyclic loading tests were carried out on a steel beam-column subassembly equipped with the proposed devices. An analytical model was then developed to validate the experimental results. A performance point ratio (PPR) was presented to optimize the design parameters of the retrofit system, and a performance-based seismic design strategy was developed based on the PPR. The retrofit system's effectiveness and the presented performance-based design approach were evaluated through case study models, and the analysis results demonstrated that the developed retrofit system and the performance-based design procedure were effective in retrofitting structures for multi-level design objectives.

• 한국지진공학회논문집
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• 제26권1호
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• pp.39-48
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• 2022

Many piping systems installed in the power plant are directly related to the safety and operation of the plant. Various dampers have been applied to the piping system to reduce the damage caused by earthquakes. In order to reduce the vibration of the piping system, this study developed a steel coil damper (SCD) with a straightforward structure but excellent damping performance. SCD reduces the vibration of the objective structure by hysteretic damping. The new SCD damper can be applied to high-temperature environments since it consists of steel members. The paper introduces a design method for the elastoplastic coil spring, which is the critical element of SCD. The practical applicability of the design procedure was validated by comparing the nonlinear force-displacement curves calculated by design equations with the results obtained from nonlinear finite element analysis and repeated loading test. It was found that the designed SCD's have a damping ratio higher than 25%. In addition, this study performed a set of seismic tests using a shaking table with an existing piping system to verify the vibration control capacity on the piping system by SCD. Test results prove that the SCD can effectively control the displacement vibration of the piping system up to 80%.

• 한국전산구조공학회논문집
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• 제24권4호
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• pp.457-462
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• 2011

본 논문은 지진응답을 제어하기 위해 다층 건물에 설치된 마찰감쇠기의 간단한 설계절차를 제안하였다. 마찰감쇠기는 비선형성이 강하므로 마찰감쇠기가 설치된 건물의 제어효과를 파악하는 것은 어렵다. 마찰감쇠기의 제어력은 층간속도에 영향을 받으므로, 인접한 모드가 서로 연계된다. 따라서 응답은 공진일 때 안정상태응답으로 가정하여 유도하였다. 첫째로 지진하중에 대한 정해응답을 구하는 것은 불가능하므로 조화가진을 받을 때의 근사해를 유도하였다. 둘째, 다층 건물을 단자유도로 변환하기 위해서 모드해석이 수행되었다. 셋째, 근사해를 이용하여 등가감쇠비를 유도하였다. 그리고 등가감쇠비를 이용하여 응답감소계수를 제안하였다. 마지막으로, 마찰감쇠기의 마찰력을 응답감소계수에 의해 설계하고 설계된 감쇠기를 7개의 지진파를 통해 검증하였다. 비선형해석 결과가 제안된 절차의 유효성을 확인하였다.

• 한국공간구조학회논문집
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• 제12권1호
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• pp.99-108
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• 2012

본 연구에서는 지진하중을 받는 대공간 구조물의 지진응답을 저감시키기 위하여 돔 구조물에 대한 동조질량제어장치(TMD)의 적용성을 검토하였다. 이를 위하여 돔 구조물의 기본적인 동적특성을 가지고 있으며 가장 간단한 구조이기도 한 스타 돔 구조물에 수동형 TMD를 설치하여 지진응답 제어성능을 평가하였다. 본 연구에서는 KBC2009에 따른 인공 지진하중을 수평방향과 연직방향으로 가하여 스타 돔 구조물에 대한 지진응답을 분석하였으며 이를 바탕으로 TMD의 설치에 따른 스타 돔 구조물의 지진응답 제어성능을 분석하였다. 해석결과 다음과 같은 결론을 얻을 수 있었다. 지진하중의 방향에 반응하는 스타 돔 구조물의 진동모드 분석을 통하여 수동 TMD를 설치하는 것이 지진응답 제어에 있어서 효과적인 것을 확인할 수 있었다.