• Title, Summary, Keyword: Metallic damper

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Structural Performance of RC Frame with SAFE Damper (SAFE댐퍼 보강골조의 구조성능 실험적 평가)

  • So, Byeong-Chan;Lee, Chang-Hwan;Ju, Young-Kyu
    • Journal of Korean Association for Spatial Structures
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    • v.15 no.1
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    • pp.85-94
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    • 2015
  • SAFE damper is a hybrid damper which is comprised of a friction damper and a metallic damper. These two dampers combine to resist external energy in stages. Under minor earthquake loads, the friction damper operates alone. However, the friction damper and metallic damper dissipate the energy together when a severe earthquake occurs. In comparison with other methods for seismic retrofitting, the SAFE damper has many advantages. The SAFE damper doesn't cause damage to façade of the building, and the construction period can be reduced when retrofitting. This paper describes experiments evaluating the structural performance of the SAFE damper. From the results, it was found that the structural performance of a conventional RC bare frame can be significantly improved by the installation of the SAFE damper.

Seismic Resistance Response of Railway Station Building Retrofitted by Metallic Dampers (강재댐퍼를 적용한 역사 건물의 내진 응답)

  • Lee, Hyun-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.2
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    • pp.82-88
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    • 2010
  • The purpose of this research is a seismic capacity evaluation and strengthening of existing railway station buildings, which were constructed before the seismic design code activated. The seismic capacity of 2nd story RC station building is evaluated by using nonlinear time-history analysis. Analysis results are checked by story drift ratio and story shear, which are described in design code. As a result, the story shears are exceeding the base shear of the design code, the appropriate seismic strengthening methods are needed. To improve the seismic capacity, metallic dampers are used. Evaluation parameters are metallic damper shape and damper installation methods. Dampers are installed in four places in X and Y directions of station buildings. By reviewing of time-history analysis results, the metallic damper, which is installed inverted K-brace type, shows a better seismic performance than other damper shape and installation methods.

Rocking Behavior of Clamped Shape Metallic Damper (꺽쇠형 강재 댐퍼의 록킹 거동)

  • Lee, Hyun-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.19 no.2
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    • pp.27-34
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    • 2019
  • This study proposes a technique to dissipate the energy of a rocking wall installed on a frame by using a metallic damper. The rocking behavior is to turn left and right about the wall vertical axis. The development system is a method of dissipating energy by installing a damper which is the like on a large displacement portion. Experimental results showed that in case of shorter strut make strength capacity increasement and in case of longer strut make deformation capacity increasement. The higher the strut height, the better the energy dissipation capacity. The proposed equation for estimating the steel damper strength applied to this study is a straight type strut damper. However, it is not suitable for calculation of the strength of clamped type strut damper where both flexural behavior and shear behavior are mixed.

Evaluation on Hysteretic Behaviors of V Shaped Metallic Dampers (V형 강재댐퍼의 이력특성 평가)

  • Lee, Hyun Ho;Kim, Seh Il
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.1
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    • pp.254-262
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    • 2011
  • The purpose of this study is the development of V shaped metallic damper, which is superior than slit damper in energy dissipation capacity. For this purpose, 9 metallic damper specimens were prepared and shear testing were performed. According to test results, the V shaped metallic damper with strut height of 270mm and strut angle of $60^{\circ}$ shows a better seismic performance than any other specimens. The result of comparison with the yield strength of the dampers using the existing strength formula shows that V type metal dampers were highly evaluated than others within analyzing existing experimental result.

A Study on the Earthquake Response Characteristics of Steel Frames with Metallic Damper (강재 댐퍼를 부착한 철골조의 지진응답특성에 관한 연구)

  • Lee, Seung-Jae;Park, Jae-Seong;Oh, Sang-Hoon
    • 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.

Shaking table test and numerical analysis of a combined energy dissipation system with metallic yield dampers and oil dampers

  • Zhou, Qiang;Lu, Xilin
    • Structural Engineering and Mechanics
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    • v.17 no.2
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    • pp.187-201
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    • 2004
  • A shaking table test on a three-story one-bay steel frame model with metallic yield dampers and their parallel connection with oil dampers is carried out to study the dynamic characteristics and seismic performance of the energy dissipation system. It is found from the test that the combined energy dissipation system has favorable reducing vibration effects on structural displacement, and the structural peak acceleration can not evidently be reduced under small intensity seismic excitations, but in most cases the vibration reduction effect is very good under large intensity seismic excitations. Test results also show that stiffness of the energy dissipation devices should match their damping. Dynamic analysis method and mechanics models of these two dampers are proposed. In the analysis method, the force-displacement relationship of the metallic yield damper is represented by an elastic perfectly plastic model, and the behavior of the oil damper is simulated by a velocity and displacement relative model in which the contributions of the oil damper to the damping force and stiffness of the system are considered. Validity of the analytical model and the method is verified through comparison between the results of the shaking table test and numerical analysis.

Displacement and Velocity Dependence of Clamped Shape Metallic Dampers (꺽쇠형 강재 댐퍼의 변위 및 속도 의존성)

  • Lee, Hyun Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.2
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    • pp.62-70
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    • 2013
  • The purpose of this study is the displacement and velocity dependence evaluation of clamped shape metallic damper, which were evaluated superior in energy dissipation capacity than straight type slit damper. For this purpose, 6 metallic damper specimens are prepared and dependence test are performed. Test variables are displacement dependence and velocity dependence. According to displacement dependence test results, larger target displacement (50mm) shows lower cyclic numbers and cumulated energy dissipated area than lower target displacement (25mm). Also it shows higher strength and early failure than short target displacement. In velocity dependence evaluation, fast target velocity (60mm/sec) shows lower cyclic numbers and cumulated energy dissipated area than slow target velocity (40mm/sec). Therefore the hysteresis dependence of metallic damper were evaluated as close relation to the loading displacement and velocity conditions.

Hysteretic Behaviors of Metallic Dampers with the Various Slit Shape (슬릿형상에 따른 강재댐퍼의 이력거동)

  • Lee, Hyun Ho;Kim, Seh Il
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.5
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    • pp.199-208
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    • 2011
  • The purpose of this study is to evaluate of the strength and deformation capacity of metallic dampers with the variable slit shape. For this purpose, 12 metallic damper specimens were prepared and shear testing was performed. According to the test results, the S shaped metallic damper with the strut height of 200mm and angle of $60^{\circ}$ shows better hysteretic performance than any other specimens. By making a comparison between the yield strength in test and the proposed strength formula, test results shows larger yield strength than calculation method.

A methodology for design of metallic dampers in retrofit of earthquake-damaged frame

  • Zhang, Chao;Zhou, Yun;Weng, Da G.;Lu, De H.;Wu, Cong X.
    • Structural Engineering and Mechanics
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    • v.56 no.4
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    • pp.569-588
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    • 2015
  • A comprehensive methodology is proposed for design of metallic dampers in seismic retrofit of earthquake-damaged frame structures. It is assumed that the metallic dampers remain elastic and only provide stiffness during frequent earthquake (i.e., earthquake with a 63% probability of exceedance in 50-year service period), while in precautionary earthquake (i.e., earthquake with a 10% probability of exceedance in 50-year service period), the metallic dampers yield before the main frame and dissipate most of the seismic energy to either prevent or minimize structural damages. Therefore by converting multi-story frame to an equivalent single-degree-of-freedom system, the added stiffness provided by metallic dampers is designed to control elastic story drifts within code-based demand under frequent earthquake, and the added damping with the combination of added stiffness influences is obtained to control structural stress within performance-based target under precautionary earthquake. With the equivalent added damping ratio, the expected damping forces provided by metallic dampers can be calculated to carry out the configuration and design of metallic dampers along with supporting braces. Based on a detailed example for retrofit of an earthquake-damaged reinforced concrete frame by using metallic dampers, the proposed design procedure is demonstrated to be simple and practical, which can not only meet current China's design codes but also be used in retrofit design of earthquake-damaged frame with metallic damper for reaching desirable performance objective.

Mitigating Seismic Response of RC Framed Apartment Building Using Isotropic Hysteretic Steel Dampers (등방성 이력형 강재댐퍼를 이용한 RC 라멘조 아파트건물의 지진응답 개선)

  • Chun, Young-Soo;Bang, Jong-Dae
    • LHI Journal of Land, Housing, and Urban Affairs
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    • v.5 no.2
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    • pp.107-114
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    • 2014
  • Passive energy dissipation systems for seismic applications have been under development for a number of years with a rapid increase in implementations starting in the mid-1990s in many countries. A metallic hysteretic damper has most commonly been used for seismic protection of structures in domestic area because they present high energy-dissipation potential at relatively low cost and easy to install and maintain. This paper presents an analytical case study of the effectiveness of isotropic hysteretic metallic damper(IHMD) called Kagome as a passive dissipative device in reducing structural response during seismic excitation. An eighteen-story RC framed apartment building is studied with and without IHMD. Results demonstrate the feasibility of these techniques for seismic mitigation. The inclusion of supplemental passive energy dissipation devices in the form of IHMD proved to be a very effective method for significantly reducing the seismic response of the building investigated.