• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.147-154
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• 1998

The purpose of this paper is to propose the draft guidelines of seismic isolation design of Liquid Metal Reactor (LMR) using high damping laminated rubber bearings. The scopes of guidelines include design requirements of a seismically isolated system and components, seismic isolator, isolation system, interface system between seismic isolation and non-seismic isolation part, qualification and acceptance tests of seismic isolator, seismic isolation reliability, and seismic safety and monitoring system. Proposed guidelines shall be revised to extend to general design guideline for nuclear facilities by further research and discussions.

• Journal of Korean Association for Spatial Structures
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• v.16 no.4
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• pp.37-44
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• 2016

The seismic isolation system reduces the seismic vibration that is transmitted from foundation to upper structure. This seismic isolation system can be classified into base isolation and mid-story isolation by the installation location. In this study, the seismic behavior of dome structure with mid-story isolation is analyzed to verify the effect of seismic isolation. Mid-story isolation is more effective than base isolation to reduce the seismic responses of roof structure. Also, this isolation would be excellent in structural characteristics and construction.

• Journal of Korean Association for Spatial Structures
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• v.19 no.2
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• pp.109-116
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• 2019

In this study, the seismic response is investigated by using a relatively low-rise building under torsion-prone conditions and three seismic loads with change of the location of the seismic isolation system. LRB (Lead Rubber Bearing) was used for the seismic isolator applied to the analytical model. Fixed model without seismic isolation system was set as a basic model and LB models using seismic isolation system were compared. The maximum story drift ratio and the maximum torsional angle were evaluated by using the position of the seismic layer as a variable. It was confirmed that the isolation device is effective for torsional control of planar irregular structures. Also, it was shown that the applicability of the mid-story seismic isolation system. Numerical analyses results presented that an isolator installed in the lower layer provided good control performance for the maximum story drift ratio and the maximum torsional angle simultaneously.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.8
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• pp.149-156
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• 2019

In this study, dynamic responses of high - rise buildings were analyzed through the change of horizontal stiffness and yield strength among characteristics of seismic isolation system by applying middle - layer seismic isolation system to high - rise buildings of 120m height. As a result in order to prevent the displacement of the isolation layer and to control the maximum torsion angle, it is possible to appropriately control by increasing or decreasing the horizontal stiffness and the yield strength. However, depending on the maximum torsional angle and the hysteretic behavior of the seismic isolation system, excessive yield strength and horizontal stiffness increase may induce the elastic behavior of the structure and amplify the response. Therefore, it is considered that it is necessary to select the property value of the appropriate isolation device.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.3
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• pp.125-135
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• 2017

Various seismic isolation methods are being applied to bridges and buildings to improve their seismic performance. Most seismic isolation systems are the structural seismic isolation systems. In this study, the seismic performance of geotechnical seismic isolation system capable of isolating the lower foundation of the bridge structure from ground was evaluated. The geotechnical seismic isolation system was built with teflon, and the model structure was made by adopting the similitude law. The response acceleration for sinusoidal waves of various amplitudes and frequencies and seismic waves were analyzed by performing 1-G shaking table experiments. Fixed foundation, Sliding foundation, and Rocking foundation were evaluated. The results of this study indicated that the Teflon-type seismic foundation isolation system is effective in reducing the acceleration transmitted to the superstructure subject to large input ground motion. Response spectrum of the Rocking and Sliding foundation structures moves to the long period, while that of Fixed foundation moves to short period.

• Land and Housing Review
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• v.4 no.2
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• pp.185-192
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• 2013

This study presents application effects of hybrid seismic isolation system to realize high seismic performance for low-rise lightweight buildings through a non-linear analysis and onsite experiments. The complex seismic isolation system applied in this study is a method of mixing sliding bearing and laminated rubber bearing in order to overcome limitation of laminated rubber bearing in increasing natural period of the whole seismic isolation system. As a result of the non-linear analysis, seismic isolation buildings designed with complex seismic isolation system are safe because its maximum response displacement is within allowable design displacement even for a strong earthquake which rarely occurs and its maximum response shear is less than design seismic force. As a result of the onsite experiment, the rigidity of seismic isolation stories corresponds to approximately 95.8% of the design equivalent stiffness value. This indicates that actual properties of the whole seismic isolation system correspond to design values.

• Journal of Korean Association for Spatial Structures
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• v.18 no.1
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• pp.109-116
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• 2018

As the number of high-rise buildings increases, a mid-story isolation system has been proposed for high-rise buildings. Due to structural problems, an appropriate isolation layer displacement is required for an isolation system. In this study, the mid-story isolation system was designed and the seismic response of the structure was investigated by varying the yield strength and the horizontal stiffness of the seismic isolation system. To do this, a model with an isolation layer at the bottom of $15^{th}$ floor of a 20-story building was used as an example structure. Kobe(1995) and Nihonkai-Chubu(1983) earthquake are used as earthquake excitations. The yield strength and the horizontal stiffness of the seismic isolation system were varied to determine the seismic displacement and the story drift ratio of the structure. Based on the analytical results, as the yield strength and horizontal stiffness increase, the displacement of the isolation layer decreases. The story drift ratio decreases and then increases. The displacement of the isolation layer and the story drift ratio are inversely proportional. Increasing the displacement of the isolation layer to reduce the story drift ratio can cause the structure to become unstable. Therefore, an engineer should choose the appropriate yield strength and horizontal stiffness in consideration of the safety and efficiency of the structure when a mid-story isolation system for a high-rise building is designed.

• Journal of Korean Association for Spatial Structures
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• v.18 no.1
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• pp.55-65
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• 2018

In order to reduce the seismic response of the spatial structure, a seismic isolation system with sufficient flexibility is used. The natural period of structure with seismic isolation system got be long to avoid prominent period. In this study, The seismic response of the truss-arch structure, which is modeled in three types according to the rise-span ratio is analyzed on El-centro, Northridge and Artificial Earthquake and compared with the seismic response of the truss-arch structure with lead rubber bearing(LRB). When seismic load is applied to the truss arch with isolation system, the horizontal acceleration response of the truss arch is reduced and vertical seismic response is also reduced. The application of the seismic isolation system is effective in controlling the seismic response.

• Journal of Korean Association for Spatial Structures
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• v.19 no.3
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• pp.51-59
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• 2019

A hybrid mid-story seismic isolation system with a smart damper has been proposed to mitigate seismic responses of tall buildings. Based on previous research, a hybrid mid-story seismic isolation system can provide effective control performance for reduction of seismic responses of tall buildings. Structural design of the hybrid mid-story seismic isolation system is generally performed after completion of structural design of a building structure. This design concept is called as an iterative design which is a general design process for structures and control devices. In the iterative design process, optimal design solution for the structure and control system is changed at each design stage. To solve this problem, the integrated optimal design method for the hybrid mid-story seismic isolation system and building structure was proposed in this study. An existing building with mid-story isolation system, i.e. Shiodome Sumitomo Building, was selected as an example structure for more realistic study. The hybrid mid-story isolation system in this study was composed of MR (magnetorheological) dampers. The stiffnessess and damping coefficients of the example building, maximum capacity of MR damper, and stiffness of isolation bearing were simultaneously optimized. Multi-objective genetic optimization method was employed for the simultaneous optimization of the example structure and the mid-story seismic isolation system. The optimization results show that the simultaneous optimization method can provide better control performance than the passive mid-story isolation system with reduction of structural materials.

• Structural Engineering and Mechanics
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• v.40 no.3
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• pp.315-334
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• 2011

Seismic isolated building structures are examined in this study. The triple concave friction pendulum (TCFP) is used as a seismic isolation system which is easy to be manufactured and enduring more than traditional seismic isolation systems. In the TCFP, take advantage of weight which pendulum carrying and it's geometry in order to obtain desirable result of seismic isolation systems. These systems offer advantage to buildings which subject to severe earthquake. This is result of damping force of earthquake by means of their internal constructions, which consists of multiple surfaces. As the combinations of surfaces upon which sliding is occurring change, the stiffness and effective friction change accordingly. Additionally, the mentioned the TCFP is modeled as of a series arrangement of the three single concave friction pendulum (SCFP) bearings. A two dimensional- and eight- story of a building with and without isolation system are used in the time history analysis in order to investigate of the effectiveness of the seismic isolation systems on the buildings. Results are compared with each other to emphasize efficiency of the TCFP as a seismic isolation device against the other friction type isolation system like single and double concave surfaces. The values of the acceleration, floor displacement and isolator displacement obtained from the results by using different types of the isolation bearings are compared each other. As a result, the findings show that the TCFP bearings are more effective devices for isolation of the buildings against severe earthquakes.