• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.499-504
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• 2008

Recently, the problem controlling lateral drift is important in tall buildings for improvement in economic efficiency and habitability. But, the Outrigger System, general used for tall building in Korea, has weak points with the occupancy of special space and the long duration of works. The dampers are applied to actively control building's response by earthquake and wind load in these days. Accordingly, we analyze the effect of the drift control using various dampers to substitute for the Outrigger System as the efficient system in tall buildings.

• Earthquakes and Structures
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• v.16 no.6
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• pp.743-755
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• 2019

In this paper, a new system of seismic isolation for buildings - called suspended columns - is introduced. In this method, the building columns are placed on the hinged cradle seats instead of direct connection to the foundation. In this system, each of the columns is put on a seat hung from its surrounding area by a number of cables, for which cavities are created inside the foundation around the columns. Inside these cavities, the tensile cables are hung. Because of the flexibility of the cables, the suspended seats vibrate during an earthquake and as a result, there is less acceleration in the structure than the foundation. A Matlab code was written to analyze and investigate the response of the system against the earthquake excitations. The findings showed that if this system is used in a building, it results in a significant reduction in the acceleration applied to the structure. A shear key system was used to control the structure for service and lateral weak loads. Moreover, the effect of vertical acceleration on the seismic behavior of the system was also investigated. Effect of the earthquake characteristic period on the system performance was studied and the optimum length of the suspension cables for a variety of the period ranges was suggested. In addition, measures have been taken for long-term functioning of the system and some practical feasibility features were also discussed. Finally, the advantages and limitations of the system were discussed and compared with the other common methods of seismic isolation.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.473-480
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• 2003

In these days, The base isolation system is often used improve the seismic capacity of the structure Instead of conventional techniques of strengthening the structural members. The purpose of this study is to evaluate dynamic property evaluation of control equipment using Lead Rubber Bearing. In this study, analysis numerical was performed to determine the optimal dynamic property of lead rubber bearing and damper which minimize the response of base from in main control room. Also the analytical results was composed with the test results peformed in previous study

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.3
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• pp.149-156
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• 2020

The vibration control device such as the damper can be used to reinforce the seismic performance of structures. The damper is activated by the deformation of structures during earthquake; however, the deformation of structures is extremely small, causing difficulty in using the damper. Therefore, there is a need for a method capable of amplifying small deformities and transmitting them to the damper. The purpose of this paper is to develop and evaluate a displacement amplification seismic system using cable-pulley. The appropriate cable was selected through a cable tensile performance test and the results of the frame experiment were compared with theoretical displacement amplification ratio values. As a result, it may be said that the proposed system using cable-pulley is useful for displacement amplification.

• Steel and Composite Structures
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• v.8 no.6
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• pp.511-530
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• 2008

This paper discusses a feasibility of a new type of two-way system for single layer lattice domes with nodal eccentricity by investigating the dynamic behavior under earthquake motions. The proposed dome is composed of two main arches, intersecting each other with T-joint struts to provide space for tensioning membranes. The main purposes of this study are to calculate the nonlinear dynamic response under severe earthquake motions and to see the possibility of using this new type of two-way system for single layer lattice domes against earthquake motions. The results show that the main arches remain elastic except yielding of the joints of strut members that can be used to absorb some amount of strain energy at strong earthquake motion. Consequently, deformation of the main arches can be reduced and any heavy damages on the main arches can be minimized. A kind of damage-control characteristic appeared in this system may be utilized against severe earthquake motions, showing a possibility of designing a new type of single layer lattice dome.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.341-348
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• 2002

In these days, The base isolation system is often used to improve the seismic capacity of the structures instead of conventional techniques of strengthening the structural members. The purpose of this study is to evaluate dynamic property evaluation of control equipment using lead Lead Rubber Bearing. In this study, a base isolation test of seismic monitoring control cabinet with LRB(lead rubber bearing) was performed. The cabinet will be installed on access floor in MCR(main control room) of nuclear power plant. Details and dynamic characteristics of the access floor were considered in the construction of testing specimen. N-S component of El Centre earthquake was used as seismic input motion. Acceleration response spectrums in the top of cabinets showed that the first mode frequency of cabinet with LRB(lead rubber bearing) was shifted to 7.5 Hz in compared with 18Hz of cabinet without LRB and the maximum peak acceleration was reduced in a degree of22 percent from 2.35 g to 1.84 g

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.429-436
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• 2005

In this study, we made two types of main control room floor systems (Type I, Type II) and several shaking table tests with and without isolation system were conducted to evaluate floor isolation effectiveness of LRB(Lead Rubber Bearing). Both type showed large difference according to input earthquake signals, but showed little difference according to floor type. It is required to make LRB of which design frequency is below 1Hz when applied to main control room of NPP, but considering much difficulties in making such LRB, it is recommended that consideration should be taken into account when applied to main control room of NPP.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.3 s.73
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• pp.239-245
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• 2006

In this paper, the performance of a toggle brace-MR damper system is evaluated for the control of the structure excited by earthquake load and the non-linearity of the toggle system is investigated. Considering that the control force of MR damper described by Bingham model is a function of velocity, velocity amplification factor by the toggle brace system is calculated and the effect of toggle configuration on the amplification factor is also evaluated. Numerical results show that the control performance can be largely enhanced using toggle brace system especially for the case that the MR damper installed with conventional brace system such as Chevron and diagonal cannot provide enough control force under severe earthquake load.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.505-512
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• 2003

As large structures such as highrise buildings and cable-stayed bridges become lighter and more flexible, the necessity of structural control for reducing excessive displacement and acceleration due to seismic excitation is increased. As a means to minimize seismic damages, various base isolation systems are adopted or considered for adoption. In this study, the seismic performance of M dampers are studied and compared with that of the NZ system as a base isolation system As the control algorithm of the MR damper, the clipped-optimal control(applied LQR method) is employed. A five-story building is modeled and the seismic performance of the two systems subjected to three different earthquakes is compared. The results show that the M damper system can provide superior protection than the NZ system for a wide range of ground motions.

• 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.