• 제목/요약/키워드: steel hysteretic damper

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A ductile steel damper-brace for low-damage framed structures

  • Javidan, Mohammad Mahdi;Kim, Jinkoo
    • Steel and Composite Structures
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    • 제44권3호
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    • pp.325-337
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    • 2022
  • In this research, an earthquake-resistant structural system consisting of a pin-connected steel frame and a bracing with metallic fuses is proposed. Contrary to the conventional braced frames, the main structural elements are deemed to remain elastic under earthquakes and the seismic energy is efficiently dissipated by the damper-braces with an amplification mechanism. The superiority of the proposed damping system lies in easy manufacture, high yield capacity and energy dissipation, and an effortless replacement of damaged fuses after earthquake events. Furthermore, the stiffness and the yield capacity are almost decoupled in the proposed damper-brace which makes it highly versatile for performance-based seismic design compared to most other dampers. A special attention is paid to derive the theoretical formulation for nonlinear behavior of the proposed damper-brace, which is verified using analytical results. Next, a direct displacement-based design procedure is provided for the proposed system and an example structure is designed and analyzed thoroughly to check its seismic performance. The results show that the proposed system designed with the provided procedure satisfies the given performance objective and can be used for developing highly efficient low-damage structures.

복합 슬릿-마찰 감쇠장치가 적용된 철근 콘크리트 특수 모멘트 저항골조의 내진성능 평가 (Seismic Performance Evaluation of Special Reinforced Concrete Moment Resisting Frames With Hybrid Slit-Friction Damper)

  • 이준호;김기철;김진구
    • 한국공간구조학회논문집
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    • 제17권4호
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    • pp.35-42
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    • 2017
  • This study develops a new hybrid passive energy dissipation device for seismic rehabilitation of an existing structure. The device is composed of a friction damper combined with a steel plate with vertical slits as a hysteretic damper. Analytical model is developed for the device, and the capacity of the hybrid device to satisfy a given target performance is determined based on the ASCE/SEI 7-10 process. The effect of the device is verified by nonlinear dynamic analyses using seven earthquake records. The analysis results show that the dissipated inelastic energy is concentrated on the hybrid damper and the maximum interstory drift of the SMRF with damping system satisfies the requirement of the current code.

Numerical and experimental study of the nested-eccentric-cylindrical shells damper

  • Reisi, Alireza;Mirdamadi, Hamid Reza;Rahgozar, Mohammad Ali
    • Earthquakes and Structures
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    • 제18권5호
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    • pp.637-648
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    • 2020
  • In this study, a new steel cylindrical shell configuration of the dissipative energy device is proposed to improve lateral ductility and to reduce the damage of the structures against seismic forces. Four nested-eccentric- cylindrical shells are used to constructing this device; therefore, this proposed device is named nested-eccentric-cylindrical shells damper (NECSD). The particular configuration of the nested-eccentric-cylindrical shells is applied to promote the mechanical characteristics, stability, and overall performance of the damper in cyclic loads. Shell-type components are performed as a combination of series and parallel non-linear springs into the in-plan plastic deformation. Numerical analysis with respect to dimensional variables are used to calculate the mechanical characteristics of the NECSD, and full-scale testing is conducted for verifying the numerical results. The parametric study shows the NECSD with thin shells were more flexible, while devices with thick shells were more capacious. The results from numerical and experimental studies indicate that the NECSD has a stable behavior in hysteretic loops with highly ductile performance, and can provide appropriate dissipated energy under cyclic loads.

강봉댐퍼로 보강한 기존 저층 철근콘크리트 필로티 건물의 내진성능 (Seismic Performance of an Existing Low-Rise Reinforced Concrete Piloti Building Retrofitted by Steel Rod Damper)

  • 백은림;오상훈;이상호
    • 한국지진공학회논문집
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    • 제18권5호
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    • pp.241-251
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    • 2014
  • In this study, shaking table test was carried out to evaluate the seismic behavior and performance of low-rise reinforced concrete (RC) piloti structures with and without retrofit. The specimens were designed considering the characteristics of existing building with pilotis such as natural period, distribution factor of strength and stiffness between columns and core wall on the first soft story. The test for the non-retrofit specimen showed that damage was concentrated on the stiffer member on the same floor as the core wall failed by shear fracture whereas columns experienced slight flexural cracks. Considering the failure mode of the non-retrofit specimen, the retrofit method using steel rod damper was presented for improving the seismic performance of piloti structures. The results of the test for retrofit specimen revealed that the retrofit method was effective for controlling the damage as the main RC structural members were not destroyed and most of input energy was dissipated by hysteretic behavior of the damper.

Full-scale tests of two-story RC frames retrofitted with steel plate multi-slit dampers

  • Javidan, Mohammad Mahdi;Nasab, Mohammad Seddiq Eskandari;Kim, Jinkoo
    • Steel and Composite Structures
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    • 제39권5호
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    • pp.645-664
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    • 2021
  • There is a growing need of seismic retrofit of existing non-seismically designed structures in Korea after the 2016 Gyeongju and 2017 Pohang earthquakes, especially school buildings which experienced extensive damage during those two earthquakes. To this end, a steel multi-slit damper (MSD) was developed in this research which can be installed inside of partition walls of school buildings. Full-scale two-story RC frames were tested with and without the proposed dampers. The frames had structural details similar to school buildings constructed in the 1980s in Korea. The details of the experiments were described in detail, and the test results were validated using the analysis model. The developed seismic retrofit strategy was applied to a case study school building structure, and its seismic performance was evaluated before and after retrofit using the MSD. The results show that the developed retrofit strategy can improve the seismic performance of the structure to satisfy a given target performance level.

Experimental and analytical investigations on seismic behavior of ductile steel knee braced frames

  • Zahrai, Seyed Mehdi;Jalali, Meysam
    • Steel and Composite Structures
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    • 제16권1호
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    • pp.1-21
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    • 2014
  • Knee Braced Frame (KBF) is a special form of ductile eccentrically braced frame having a diagonal brace connected to a knee element, as a hysteretic damper, instead of beam-column joint. This paper first presents an experimental investigation on cyclic performance of two knee braced single span one-story frame specimens. The general test arrangement, specimen details, and most relevant results (failure modes and hysteretic curves) are explained. Some indexes to assess the seismic performance of KBFs, including ductility; response reduction factor and energy dissipation capabilities are also subsequently discussed. Experimental results indicate that the maximum equivalent damping ratios achieved by test frames are 21.8 and 23% for the specimens, prior to failure. Finally, a simplified analytical model is derived to predict the bilinear behavior of the KBFs. Acceptable conformity between analytical and experimental results proves the accuracy of the proposed model.

고감쇠고무와 강재슬릿이 결합된 하이브리드 댐퍼의 실험적 구조성능평가 (Experimental Structural Performance Evaluation of Hybrid Damper Combining with High Damping Rubber and Steel Slit)

  • 이준호;박병태;김유성
    • 한국공간구조학회논문집
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    • 제22권4호
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    • pp.23-30
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    • 2022
  • It is effective to apply hybrid damping device that combine separate damping device to cope with various seismic load. In this study, HRS hybrid damper(hybrid rubber slit damper) in which high damping rubber and steel slit plate are combined in parallel was proposed and structural performance tests were performed to review the suitability for seismic performance. Cyclic Loading tests were performed in accordance with criteria presented in KDS 41 17 00 and MOE 2019. As a result of the test, the criteria of KDS 41 17 00 and MOE2019 was satisfied, and the amount of energy dissipation increased due to the shear deformation of the high-damping rubber at low displacement. Result of performing the RC frame test, the allowable story drift ratio was satisfied, and the amount of energy dissipation increased in the reinforced specimen compared to the non-reinforced specimen.

Experimental study on lead extrusion damper and its earthquake mitigation effects for large-span reticulated shell

  • Yang, M.F.;Xu, Z.D.;Zhang, X.C.
    • Steel and Composite Structures
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    • 제18권2호
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    • pp.481-496
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    • 2015
  • A Lead Extrusion Damper (LED) is experimentally studied under various frequencies and displacement amplitudes. Experimental results show that the force-displacement hysteresis loops of the LED are close to rectangular and the force-velocity hysteresis loops exhibit nonlinear hysteretic characteristic. Also, the LED can provide consistent energy dissipation without any stiffness degradation. Based on the experimental results, a mathematical model is then proposed to describe the effects of frequency and displacement on property of LED. It can be proved from the comparison between experimental and numerical results that the mathematical model can accurately describe the mechanical behavior of LED. Subsequently, the seismic responses of the Schwedler reticulated shell structure with LEDs are analyzed by ANSYS software, in which three different installation forms of LEDs are considered. It can be concluded that the LED can effectively reduce the displacement and acceleration responses of this type of structures.

강재 슬래브 이력형 댐퍼(SSHD)를 이용한 중·저층 RC 격자 구조물의 내진성능 향상에 관한 연구 (A Study on the Seismic Performance Improvement of Mid and Low-Rise RC Grid Structures Using Steel Slab Hysteretic Damper)

  • 김동백;이인덕;최정호
    • 한국재난정보학회 논문집
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    • 제15권3호
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    • pp.418-426
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    • 2019
  • 연구목적: 내진성능이 부족한 중 저층의 RC 격자 구조물의 내진능력을 해석한 후, 보와 기둥의 내진성능 개선을 위해 강재 슬래브 이력형 댐퍼(SSHD)를 설치하고, 지진이 발생할 때 구조물의 손상 및 인적피해를 최소화 하는 방안을 제시하는 데 그 목적이 있다. 연구방법: 내진설계가 되지 않은 격자 형태의 전철 역사를 대상으로 내진성능을 파악하고, 내진성능이 부족할 경우 공기를 최소화 할 수 있는 방법인 SSHD 시스템을 설치하는 것으로 가정하여 구조물의 내진성능 평가 및 보강을 검토한다. 연구결과: SSHD를 적용하여 구조물을 보강한 후, 고유치 해석을 수행한 결과 장변방향으로는 0.548s의 고유주기를 나타내었으며, 단변방향으로는 0.593s의 고유주기를 가지고 있는 것으로 나타났다. 결론: SSHD에 대하여 반복하중 실험을 수행 한 결과, 댐퍼의 전단강성은 103%, 에너지소산량은 111% 및 109%로 나타나고, 모든 기둥과 보 부재의 소성회전각은 $I_o$수준을 만족하는 것으로 나타나 보강효과가 충분할 것으로 판단된다.

A Study for Damping Application to Response-controlled Structure

  • Shinozaki, Yozo;Mogi, Yoshihiro;Ota, Masaaki;Yoshikawa, Hiroaki
    • 국제초고층학회논문집
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    • 제10권2호
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    • pp.149-164
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    • 2021
  • Most of high-rise buildings in Japan*1 are structure with damping systems recently. The design procedure is performance-based design (PBD), which is based on the nonlinear response history procedure (NRHP) using 2 or 3-dimentional frame model. In addition, hysteretic property of steel plates or velocity-dependent property of viscous dampers are common practice for the damping system. However, for the selection of damping system, the easy dynamic analysis of recent date may lead the most of engineers to focus attention on the maximum response only without thinking how it shakes. By nature, the seismic design shall be to figure out the action of inertia forces by complex & dynamic loads including periodic and pulse-like characteristics, what we call seismic ground motion. And it shall be done under the dynamic condition. On the contrary, we engineers engineers have constructed the easy-to-use static loads and devoted ourselves to handle them. The structures with damping system shall be designed considering how the stiffness & damping to be applied to the structures against the inertia forces with the viewpoint of dynamic aspect. In this paper we reconsider the role of damping in vibration and give much thought to the basic of shake with damping from a standpoint of structural design. Then, we present some design examples based on them.