• 한국공간구조학회논문집
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• 제22권4호
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• pp.49-57
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• 2022

In this study, based on the research results of the steel plate and steel rod dampers with rocking behavior, the moment and the drift ratio were compared and evaluated. As a test result evaluation, it was showed that the behavior of R15-200 and R15-140 was very good than other dampers. And the steel rod damper showed in-plane behavior to the loading direction, and was evaluated to prevent out-of-plane behavior that causes performance degradation.

• Steel and Composite Structures
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• 제47권2호
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• pp.185-201
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• 2023

Despite the high lateral stiffness and strength of the Concentrically Braced Frame (CBF), due to the buckling of its diagonal members, it is not a suitable system in high seismic regions. Among the offered methods to overcome the shortcoming, utilizing a metallic damper is considered as an appropriate idea to enhance the behavior of Concentrically Braced Frames (CBFs). Therefore, in this paper, an innovative steel damper is proposed, which is investigated experimentally and numerically. Moreover, a parametrical study was carried out to evaluate the effect of the mechanism (shear, shear-flexural, and flexural) considering buckling mode (elastic, inelastic, and plastic) on the behavior of the damper. Besides, the necessary formulas based on the parametrical study were presented to predict the behavior of the damper that they showed good agreement with finite element (FE) results. Both experimental and numerical results confirmed that dampers with the shear mechanism in all buckling modes have a better performance than other dampers. Accordingly, the FE results indicated that the shear damper has greater ultimate strength than the flexural damper by 32%, 31%, and 56%, respectively, for plates with elastic, inelastic, and plastic buckling modes. Also, the shear damper has a greater stiffness than the flexural damper by 43%, 26%, and 53%, respectively, for dampers with elastic, inelastic, and plastic buckling modes.

• 한국구조물진단유지관리공학회 논문집
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• 제26권5호
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• pp.66-73
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• 2022

본 연구에서는 록킹 거동을 하는 강재댐퍼에 대한 기존 연구결과를 근간으로 스트럿 높이가 동일하고 단면적이 유사한 댐퍼 7개의 실험결과를 비교하였다. 강판댐퍼로 Ldpd(횡변형 방지 상세) 없는 SI-260, SV-260, SS-260, Ldpd 있는 I-1, V-1, S-1 및 강봉댐퍼인 R20-260을 평가하였다. 또한 단면적이 0.56배인 R15-260도 같이 평가하여, 강봉댐퍼 거동 성능을 적절히 평가하고자 하였다. 중요한 연구결과는 강판댐퍼의 일방향성을 개선한 강봉댐퍼 적용의 우수성이며, 이는 모멘트 저항 능력 및 변위비 평가에서도 확인할 수 있었다. 평가결과, 강봉댐퍼인 R20-260의 성능이 가장 우수한 것으로 평가되었다. 또한 변위비 2.0까지 변형 능력을 나타내어, 충분한 내진성능을 보유한 것으로 판단된다.

• Steel and Composite Structures
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• 제45권3호
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• pp.455-466
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• 2022

Despite the considerable lateral stiffness and strength of the Concentrically Braced Frame (CBF), it suffers from low ductility and low seismic dissipating energy capacity. The buckling of the diagonal members of the CBF systems under cyclic loading ended up to the shortcoming against seismic loading. Comprehensive researches have been performing to achieve helpful approaches to prevent the buckling of the diagonal member. Among the recommended ideas, metallic damper revealed a better success than other ideas to enhance the behavior of CBFs. While metallic dampers improve the behavior of the CBF system, they increase constructional costs. Therefore, in this paper, a new steel damper with flexural mechanism is proposed, which is investigated experimentally and numerically. Also, a parametrical revision was carried out to evaluate the effect of thickness, slenderness ratio, angle of the main plate, and height of the main plates on the proposed damper. For the parametrical study, 45 finite element models were analyzed and considered. Experimental results, as well as the numerical results, indicated that the proposed damper enjoys a stable hysteresis loop without any degradation up to a high rotation equal to around 31% that is significantly considerable. Moreover, it showed a suitable performance in case of ductility and energy dissipating. Besides, the necessary formulas to design the damper, the required relations were proposed to design the elements outside the damper to ensure the damper acts as a ductile fuse.

• Steel and Composite Structures
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• 제27권5호
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• pp.633-646
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• 2018

This study investigated the seismic performance of a hybrid damper composed of a steel slit plate and friction pads, and an optimum retrofit scheme was developed based on life cycle cost. A sample hybrid damper was tested under cyclic loading to confirm its validity as a damping device and to construct its nonlinear analysis model. The effectiveness of the optimum damper distribution schemes was investigated by comparing the seismic fragility and the life cycle costs of the model structure before and after the retrofit. The test results showed that the damper behaved stably throughout the loading history. Numerical analysis results showed that the slit-friction hybrid dampers optimally distributed based on life cycle cost proved to be effective in minimizing the failure probability and the repair cost after earthquakes.

• Steel and Composite Structures
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• 제51권1호
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• pp.93-101
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• 2024

This paper presents an experimental and analytical study on a steel slit damper designed as an energy dissipative device for earthquake protection of structures considering soil-structure interaction. The steel slit damper is made of a steel plate with a number of slits cut out of it. The slit damper has an advantage as a seismic energy dissipation device in that the stiffness and the yield force of the damper can be easily controlled by changing the number and size of the vertical strips. Cyclic loading tests of the slit damper are carried out to verify its energy dissipation capability, and an analytical model is developed validated based on the test results. The seismic performance of a case study building is then assessed using nonlinear dynamic analysis with and without soil-structure interaction. The soil-structure system turns out to show larger seismic responses and thus seismic retrofit is required to satisfy a predefined performance limit state. The developed slit dampers are employed as a seismic energy dissipation device for retrofitting the case study structure taking into account the soil-structure interaction. The seismic performance evaluation of the model structure shows that the device works stably and dissipates significant amount of seismic energy during earthquake excitations, and is effective in lowering the seismic response of structures standing on soft soil.

• 한국전산구조공학회논문집
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• 제35권6호
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• pp.381-386
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• 2022

본 논문에서는 휨 항복 메커니즘을 기반으로 한 강재이력 댐퍼를 제안하기 위한 해석 및 실험적 연구를 수행하였다. 댐퍼는 휨모멘트에 의한 항복거동을 하도록 설계된 일련의 댐핑 플레이트로 구성된다. 실험 결과와 유한요소해석 결과의 비교를 통해서 본 연구에서 채택된 해석적 접근방식이 댐핑 플레이트의 형태 및 상세에 대한 민감도 연구를 수행하기에 적절함을 확인하였다. 최초에 제안된 댐퍼는 휨 항복 메커니즘을 기반으로 작동하는 것으로 고안되었으나, 댐핑 플레이트의 인장 거동에 대한 기여도가 상당할 수 있음을 관찰할 수 있었다. 댐핑 플레이트의 두께가 증가함에 따라 휨 항복에 의한 에너지 흡수량이 증가한다. 댐핑 플레이트의 두께가 감소함에 따라 인장에 의한 댐퍼의 비선형 거동 기여도가 증가하고 좌굴 발생으로 인하여 이력곡선의 형상이 댐퍼로서 불리해진다.

• 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.

• Steel and Composite Structures
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• 제53권1호
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• pp.29-43
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• 2024

In this paper, the behavior of an innovative metallic a butterfly-shaped link as damper with shear and flexural mechanism was investigated experimentally and numerically. The damper is directly attached to the diagonal member of the Concentrically Braced Frame (CBF) to prevent buckling of the braces. Since it is expected that nonlinear behavior of the system is limited to the dampers, the other parts of structures remind elastic that the damper can replaced easily after a severe earthquake. The experimental outcomes indicated that both types of dampers (with shear or flexural mechanism) pertain to stable hysteresis loops without any significant degradation in stiffness or strength. Comparing the dampers indicated that the shear damper has a greater ultimate strength (4.59 times) and stiffness (3.58 times) than flexural damper but a lower ductility (16%) and ultimate displacement (60%). Also, the shear damper has a considerable dissipation energy 14.56 times greater than flexural dampers where dissipating energy are affected by ultimate strength, stiffness and ultimate displacement. Also, based on the numerical study, the effect of main plate slenderness on the behavior of the damper was considered and the allowable slenderness was suggested to the design of the dampers. Numerical results confirmed that the flexural damper is more sensitive to the slenderness than shear damper. Accordingly, as the slenderness is less than 50 and 30, respectively, for, shear and flexural damper, no degradation in ultimate strength is realized. By increasing the slenderness, the maximum reduction of the ultimate strength, stiffness, and energy dissipation capacity reached by 16%, 7%, and 17% for SDB dampers whereas it is 3%, 33%, 20%, and 45% for MDB.

• 국제초고층학회논문집
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• 제3권1호
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• pp.35-48
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• 2014

In designing a 300 meter high skyscraper expected to be the tallest building in Japan, an earthquake-ridden country, we launched on the full-scale performance based design to ensure redundancy and establish new specifications using below new techniques. The following new techniques are applied because the existing techniques/materials are not enough to meet the established design criteria for the large-scale, irregularly-shaped building, and earth-conscious material saving and construction streamlining for reconstructing a station building are also required: ${\bullet}$ High strength materials: Concrete filled steel tube ("CFT") columns made of high-strength concrete and steels; ${\bullet}$ New joint system: Combination of outer diaphragm and aluminium spray jointing; ${\bullet}$ Various dampers including corrugated steel-plate walls, rotational friction dampers, oil dampers, and inverted-pendulum adaptive tuned mass damper (ATMD): Installed as appropriate; and ${\bullet}$ Foundation system: Piled raft foundation, soil cement earth-retaining wall construction, and beer bottle shaped high-strength CFT piles.