• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.862-873
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• 2007

Energy dissipation devices can be considered as an alternative for the seismic performance enhancement of existing structures based on the strengthened seismic design code. In this study, seismic response mitigation effects of friction dampers are investigated through the shaking table test of a full scale 3 story building structure. Frist, the bilinear force-displacement relationship of a structure-brace-friction damper system and the effect of brace-friction damper on the increase of frequency and damping ratio are identified. Second, frequency, displacement, and torque dependent characteristics of the friction damper are investigated by using harmonic load excitation tests. Finally, the shaking table tests are performed for a full scale 3 story steel frame. System identification results using random signal excitation indicated that brace-friction damper increased structural damping ratio and frequency, and El Centro earthquake test showed that brace-friction damper reduced the peak displacement and acceleration significantly. In particular, it was observed that the damping effect due to friction damper becomed obvious when the structure was excited by more intensive load causing frequent slippage of the friction dampers.

• Structural Engineering and Mechanics
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• v.64 no.2
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• pp.183-194
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• 2017

This paper presents the experimental investigation into a new type of steel-concrete hybrid outrigger system developed for the high-rise building structure. The steel truss is embedded into the reinforced concrete outrigger wall, and both the steel truss and concrete outrigger wall work compositely to enhance the overall structural performance of the tower structures under extreme loads. Meanwhile, metal dampers of low-yield steel material were also adopted as a 'fuse' device between the hybrid outrigger and the column. The damper is engineered to be 'scarified' and yielded first under moderate to severe earthquakes in order to protect the structural integrity of important structural components of the hybrid outrigger system. As such, not brittle failure is likely to happen due to the severe cracking in the concrete outrigger wall. A comprehensive experimental research program was conducted into the structural performance of this new type of hybrid outrigger system. Studies on both the key component and overall system tests were conducted, which reveal the detailed structural response under various levels of applied static and cyclic loads. It was demonstrated that both the steel bracing and concrete outrigger wall are able to work compositely with the low-yield steel damper and exhibits both good load carrying capacities and energy dispersing performance through the test program. It has the potential to be applied and enhance the overall structural performance of the high-rise structures over 300 m under extreme levels of loads.

• Structural Engineering and Mechanics
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• v.15 no.5
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• pp.513-534
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• 2003

Using fluid dampers to connect adjacent buildings for enhancing their seismic resistant performance has been recently investigated but limited to linear elastic adjacent buildings only. This paper presents a study of inelastic seismic response of adjacent buildings linked by fluid dampers. A nonlinear finite element planar model using plastic beam element is first constructed to simulate two steel frames connected by fluid dampers. Computed linear elastic seismic responses of the two steel frames with and without fluid dampers under moderate seismic events are then compared with the experimental results obtained from shaking table tests. Finally, elastic-plastic seismic responses of the two steel frames with and without fluid dampers are extensively computed, and the fluid damper performance on controlling inelastic seismic response of the two steel frames is assessed. The effects of the fundamental frequency ratio and structural damping ratio of the two steel frames on the damper performance are also examined. The results show that not only in linear elastic stage but also in inelastic stage, the seismic resistant performance of the two steel frames of different fundamental frequencies can be significantly enhanced if they are properly linked by fluid dampers of appropriate parameters.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.65-66
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• 2009

An experiment was carried out to evaluate energy dissipation capacity and hysteretic behavior of the steel slit damper. From the experiment, it was found that the steel slit damper showed a stable hysteretic behavior with excellent energy dissipation capacity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.740-745
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• 2002

To control vibration of real-size steel structure, a hybrid-type linear motor damper was designed and applied to 30m steel structure at UNISON. The LMD was tuned to the first mode natural frequency of the building. In order to use for simulation data and control parameters, dynamic response characteristics of building and damper were tested. The response of building was reduced by 10 dB with LMD and H$\infty$ algorithm. This value was similar to the result of simulation.

• Journal of Korean Association for Spatial Structures
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• v.11 no.2
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• pp.119-127
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• 2011

The purpose of this study is to propose damper system which is easy to design, which can ensure against risks, and to verify earthquake response characteristics. For this study, the pseudo dynamic earthquake response tests carried out for steel frames with metallic damper. As a result, in case of using the metallic damper as a vibration control device proposed by this study, the damper having higher stiffness than main-structure turned to the state of plasticity by little displacement has been proved to be able to absorb earthquake energy.

• Steel and Composite Structures
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• v.45 no.6
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• pp.865-876
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• 2022

The slit members have lower strength and lower stiffness, which might lead to lower energy dissipation. In order to improve the seismic performance of the slit members, the paper proposes the shear lead damper, which has stable performance and small deformation energy dissipation capacity. Therefore, the shear lead damper can set in the vertical silts of the slit member to transmit the shear force and improve energy dissipation, which is suitable for the slit member. Initially, the symmetrical teeth-shaped lead damper was tested and analyzed. Then the staggered teeth-shaped lead dampers were developed and analyzed, based on the defect analysis and build improvements of the symmetrical specimen. Based on the parameter analysis, the main influence factors of hysteretic performance are the internal teeth, the steel baffles, and the width and length of damper. Finally, the theoretical analysis was presented on the hysteretic curve. And the skeleton curve and hysteresis path were identified. Based on the above theoretical analysis, the design method was proposed, including the damping force, the hysteresis model and the design recommendations.

• Journal of Korean Society of Steel Construction
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• v.17 no.5 s.78
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• pp.617-625
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• 2005

The brace is often used to resist lateral force such as that exerted by an earthquake. Because of buckling at bifurcation load, the brace shows unstable hysteretic characteristics in the plastic zone. Therefore, in this study, the brace with damper that consists of slit plates were suggested on the purpose of preventing buckling and increasing plastic deformation capacity. The experimental results regarding the brace member were analyzed and the feasibility was also examined.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.129-132
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• 2005

The primary purpose of this investigation is to find out the shear behavior and the shear capacity of RC bare frames, brick-infilled RC frames, and damper-retrofitted RC frames and to evaluate the average shear strength of brick--infill wall. The main variables art the absence of brick infill wall and steel plate slit damper. The test results show that the shear capacity of specimen IF-DR is 2.8 times as high as that of the specimen BF and it presents the fact that the retrofitting effect and the possibility of RC frame reuse with changing the slit damper is verified. And the average shear strength of the brick infill wall is figured to be at $5.0 kgf/cm^2$.

• Wind and Structures
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• v.16 no.4
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• pp.323-340
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• 2013

An active mass damper system for flutter control of bridges is presented. Flutter stability of bridge structures is improved with the help of eccentric rotational actuators (ERA). By using a bridge girder model that moves in two degrees of freedom and is subjected to wind, the equations of motion of the controlled structure equipped with ERA are established. In order to take structural nonlinearities into consideration, flutter analysis is carried out by numerical simulation scheme based on a 4th-order Runge-Kutta algorithm. An example demonstrates the performance and efficiency of the proposed device. In comparison with known active mass dampers for flutter control, the movable eccentric mass damper and the rotational mass damper, the power demand is significantly reduced. This is of advantage for an implementation of the proposed device in real bridge girders. A preliminary design of a realization of ERA in a bridge girder is presented.