• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.393-400
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• 2003

Various types of dampers are widely adopted to reduce the seismic damages in bridges. However, dampers may be the improper solution especially in moderate seismic regions because dampers are costly for installation and require constant maintenance during life cycle. In this study, energy-dissipating sacrificial device is proposed, which sacrifices easily substitutable bridge members and dissipates the excessive energy during seismic excitations. In turns, the inelastic behavior of sacrificial members reduces the input energy of the major members, such as piers in bridges, and may prevent the major members from serious malfunction. A simplified mechanical model is developed to represent the behavior of sacrificial devices installed in a bridge. The hysteresis energy of piers is analyzed to certify performance of device under seismic loads applied to this mechanical model. The results from this study show that the proposed sacrificial energy-dissipating device can decrease excessive hysteresis energy and reduce the damage of piers under seismic excitation. Therefore, economical enhancement of the seismic performance of bridges may be possible by employing the proposed sacrificial energy-dissipating devices.

• Steel and Composite Structures
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• 제16권5호
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• pp.533-557
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• 2014

In this study, the performances of the SMRF building equipped with energy dissipating devices are studied. Three types of these structures with different heights are considered. The Added Damping and Stiffness (ADAS) devices are used as energy dissipating devices in these structures. The behavior of these structures with ADAS devices subjected to near source ground motions are investigated. Three SMRF buildings with five, ten and fifteen-story, with ADAS devices were chosen. The nonlinear time history analysis was used by applying the near source ground motions with PERFORM 3D.V4 and conclusions are drawn upon an energy criterion. The effect of PGA variation and height of the frames are also considered based on the energy criterion.

• 국제강구조저널
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• 제18권4호
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• pp.1384-1396
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• 2018

One of the failure modes observed in steel yield energy dissipating devices (SYEDs) excited by a strong earthquake would be the low-cycle fatigue failure. Fatigue cracks of a SYED are prone to initiate at the notch areas where stress concentration is usually occurred, which is demonstrated by the cyclic tests and analyses carried out for this study. Since the fatigue failure of SYEDs dramatically deteriorates their structural capacities, the thorough investigation on their fatigue life is usually required. To do this, sophisticated modeling with considering a time-consuming and complicate fracture mechanism is generally needed. This study makes an effort to investigate the low-cycle fatigue life of SYEDs predicted by a simplified method utilizing damage indices and fatigue prediction equations that are based on the plastic strain amplitudes obtained from typical finite element analyses. This study shows that the low-cycle fatigue failure of SYEDs predicted by the simplified method can be conservatively in good agreement with the test results of SYED specimens prepared for experimental validation.

• 국제초고층학회논문집
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• 제3권2호
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• pp.107-120
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• 2014

A Reinforced concrete (RC) shear wall system with coupling beams has been known as one of the most promising structural systems for high-rise buildings. However, significantly large flexural and/or shear stress demands induced in the coupling beams require special reinforcement details to avoid their undesirable brittle failure. In order to solve this problem, one of promising candidates is frictional hysteretic energy dissipating devices (HEDDs) as an alternative to the coupling beams. The introduction of frictional HEDDs into a RC shear wall system increases energy dissipation capacity and maintains the frame action after their yielding. This paper investigates the strength demands (specifically yield strength levels) with a maximum allowable ductility of frictional HEDDs based on comparative non-linear time-history analyses of a prototype RC shear wall system with traditional RC coupling beams and frictional HEDDs. Analysis results show that the RC shear wall systems coupled by frictional HEDDs with more than 50% yield strength of the RC coupling beams present better seismic performance compared to the RC shear wall systems with traditional RC coupling beams. This is due to the increased seismic energy dissipation capacity of the frictional HEDD. Also, it is found from the analysis results that the maximum allowable ductility demand of a frictional HEDD should increase as its yield strength decreases.

• 국제강구조저널
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• 제18권5호
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• pp.1508-1524
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• 2018

Hysteretic energy dissipating devices (HEDDs) have been increasingly applied to building construction to improve the seismic performance. The seismic responses of such damped structures are significantly affected by HEDD's structural properties. An accurate investigation on the propagation of HEDD's structural properties is required for reasonable evaluation of the seismic performance of a structure. This study aims to develop simplified methods that can estimate the collective uncertainty-propagation to the seismic response of damped structures employing HEDDs. To achieve this, three- and six-story steel moment-resisting frames were selected and the propagations of the individual HEDD's property-uncertainties were evaluated when they are subjected to various levels of seismic demand. Based on the result of individual uncertainty-propagations, a simplified method is proposed to evaluate the variation of seismic response collectively propagated by HEDD's property-uncertainties and is verified by comparing with the exact collective uncertainty-propagation calculated using the Monte Carlo simulation method. The proposed method, called as a modified SRSS method in this study, is established from a conventional square root of the sum of the squares (SRSS) method with the relative contributions of the individual HEDD's property-uncertainty propagations. This study shows that the modified SRSS method provides a better estimation than the conventional SRSS method and can significantly reduce computational time with reasonable accuracy compared with the Monte Carlo simulation method.

• 국제초고층학회논문집
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• 제3권1호
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• pp.21-33
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• 2014

The tied braced frame (TBF) system was developed to achieve uniform seismic inelastic demand along the height of multi-storey eccentrically braced steel frames. A modular tied braced frame (M-TBF) configuration has been recently proposed to reach the same objective while reducing the large axial force demand imposed on the vertical tie members connecting the link beams together in TBFs. M-TBFs may however experience variations in storey drifts at levels where the ties have been removed to form the modules. In this paper, the possibility of reducing the discontinuity in displacement response of a 16-storey M-TBF structure by introducing energy dissipating (ED) devices between the modules is examined. Two M-TBF configurations are investigated: an M-TBF with two 8-storey modules and an M-TBF with four 4-storey modules. Three types of ED devices are studied: friction dampers (FD), buckling restrained bracing (BRB) members and self-centering energy dissipative (SCED) members. The ED devices were sized such that no additional force demand was imposed on the discontinuous tie members. Nonlinear response history analysis showed that all three ED systems can be used to reduce discontinuities in storey drifts of M-TBFs. The BRB members experienced the smallest peak deformations whereas minimum residual deformations were obtained with the SCED devices.

• 한국구조물진단유지관리공학회 논문집
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• 제22권3호
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• pp.21-30
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• 2018

국내 공동주택 전단벽 구조시스템에 적용되는 감쇠장치는 대부분 인방형 형상으로 적용되고 있다. 인방형 감쇠장치는 좌우 전단벽을 연결하여 커플링 효과 및 추가 감쇠효과를 발휘하여 구조물 내진성능을 증대시킨다. 본 연구에서는 인방형 감쇠장치를 소개하고 감쇠장치가 적용된 구조물의 거동특성을 파악하였다. 제안된 감쇠장치는 힌지 및 변단면 형상으로 감쇠효과를 극대화시킨 구조로 유한요소 해석결과와 실험결과가 잘 일치하여 우수한 내진성능을 발휘하는 것으로 나타났으며, 해당 감쇠장치가 적용된 2차원 및 실제 공동주택 구조물을 대상으로 감쇠효과를 검토한 결과, 감쇠장치 커플링 효과로 기존구조물 대비 모든 구조물에서 내진성능 향상을 도모할 수 있었다. 본 연구에서 검토한 실제 구조물에 대해서는 비선형 정적해석 결과, 강도 및 연성능력이 향상되는 것으로 나타났고, 비선형 동적해석 결과, 층간변형각이 15%~18%, 층가속도가 20%~28%, 밑면전단력이 15%~20% 감소하는 결과를 나타냈다.

• 한국지진공학회논문집
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• 제11권3호
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• pp.87-96
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• 2007

최근 지진하중에 대한관심이 높아져 가는 가운데 내진설계가 되어 있지 않은 기존 교량의 내진성능 향상 및 신설될 교량의 구조적 기능성과 안전성을 증대시키기 위한 방안으로 희생부재형 에너지소산장치(Energy-Dissipating Sacrificial Device, EDSD)가 개발되었다. 본 연구에서는 제안된 장치가 내진성능 향상을 위한 기법으로 실제 교량에 적용될 수 있도록 실험을 통해 EDSD의 성능 및 안정성을 검토하였다. 유사동적실험 결과, EDSD는 지진하중 시 양호한 에너지 소산능력을 발휘할 것으로 예상되며 충분한 소성거동을 통해 교량의 주거더에는 손상을 거의 주지 않으며 주부재간의 연결부 또한 안전함을 알 수 있었다. 또한, 강합성 플레이트 거더교를 대상으로 EDSD를 적용하고 교각의 에너지, 수평력 및 상 하부 구조간의 상대변위 등의 지진응답특성을 분석한 결과, EDSD는 지진력을 효과적으로 감소 및 분산시키고 상 하부 구조간의 상대변위를 상당히 감소시키는 것으로 나타났다. 따라서, EDSD는 설계 지진하중 또는 그 이상의 지진하중 하에서 특별한 유지관리 없이 그 기능을 발휘할 수 있을 것으로 예상되며 우리나라와 같이 지진이 빈번히 발생하지 않는 지역에서 기능적 경제적 효과를 기대할 수 있을 것으로 판단된다.

• Steel and Composite Structures
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• 제28권6호
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• pp.691-708
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• 2018

An innovative Hybrid Passive Resistive configuration for Truss Girder Frames (HPR-TGFs) is introduced in the present study. The proposed system is principally consisting of Fluid Viscous Dampers (FVDs) and Buckling Restrained Braces (BRBs) as its seismic resistive components. Concurrent utilization of these devices will develop an efficient energy dissipating mechanism which is able to mitigate lateral displacements as well as the base shear, simultaneously. However, under certain circumstances which the presence of FVDs might not be essential, the proposed configuration has the potential to incorporate double BRBs in order to achieve the redundancy of alternative load bearing paths. This study is extending the modern Direct Displacement Based Design (DDBD) procedure as the design methodology for HPR-TGF systems. Based on a series of nonlinear time history analysis, it is demonstrated that the design outcomes are almost identical to the pre-assumed design criteria. This implies that the ultimate characteristics of HPR-TGFs such as lateral stiffness and inter-story drifts are well-proportioned through the proposed design procedure.

• Structural Engineering and Mechanics
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• 제32권5호
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• pp.587-608
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• 2009

Modern earthquake-resistant design aims to isolate architectural precast concrete panels from the structural system so as to reduce the interaction with the supporting structure and hence minimize damage. The present study seeks to maximize the cladding-structure interaction by developing an energy-dissipating cladding system (EDCS) that is capable of functioning both as a structural brace, as well as a source of energy dissipation. The EDCS is designed to provide added stiffness and damping to buildings with steel moment resisting frames with the goal of favorably modifying the building response to earthquake-induced forces without demanding any inelastic action and ductility from the basic lateral force resisting system. Because many modern building facades typically have continuous and large openings on top of the precast cladding panels at each floor level for window system, the present study focuses on spandrel type precast concrete cladding panel. The preliminary design of the EDCS was based on existing guidelines and research data on architectural precast concrete cladding and supplemental energy dissipation devices. For the component-level study, the preliminary design was validated and further refined based on the results of nonlinear finite element analyses. The stiffness and strength characteristics of the EDCS were established from a series of nonlinear finite element analyses and are discussed in detail in this paper.