• Journal of Korean Association for Spatial Structures
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• v.17 no.4
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• pp.115-122
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• 2017

In this study, performance based seismic design was performed on the shear wall structural system and the beam-column system as a variable general rebar and seismic rebar, and comparing the capacity of the two models of each system. From nonlinear analyses, the capacity of the shear wall structural system applying seismic rebar has shown a stable behavior after the maximum strength, but there is little difference. Furthermore, both models showed similar capacity between story drift and story shear force and capacity of members. These results are attributed to the fact that the seismic rebar, which is highly ductile under the seismic load applied to the target structure, does not render sufficient capacity.

• Journal of the Korean Society of Safety
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• v.28 no.4
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• pp.97-102
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• 2013

This paper presents a new strengthening method of underground box structures against seismic loads for anti-seismic capacity improvement. A threaded steel member with pressure devices(so called 'I-bracing pressure system') is used to improve seismic capacity of the RC box structure. The I-bracing pressure system is fixed the corner of opening after chemical anchor was installed by drilling hole on the box structure. The structural performance was evaluated analytically. Two bracing types of strengthening methods were used; conventional bracing method and improved I-bracing pressure system. For the performance evaluation, seismic analyses were performed on moment and shear resisting structures with and without I-bracing pressure system. Numerical results confirmed that the proposed I-bracing pressure system can enhance the seismic capacity of the underground RC box structures.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.5
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• pp.67-73
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• 2003

The present seismic analysis of Road-Bridge Design Standard is on a basis of load-based analysis which lets structures have the strength over load. In this study, the capacity spectrum method, a kind of displacement based method, which is evaluated by displacement of structure, is presented as an alternative to the analysis method based on load. Seismic capacity is performed about the existing reinforced concrete pier which has already secured seismic design by capacity spectrum method. As a result. capacity spectrum method could realistically evaluate the non-elastic behavior of structures easily and quickly and the displacement of structures for variable ground motion level. And it could efficiently apply to an evaluation of seismic capacity about the existing structure and a verification of design for capacity target of the new structure.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.2
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• pp.59-69
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• 2022

The use of dampers is being considered a means to improve the seismic performance of buildings. It may take considerable time and effort to find an optimal design solution since repeated three-dimensional nonlinear time history analyses are required. Therefore, a preliminary design procedure for seismic retrofit using hysteretic dampers was proposed in this study. In the proposed procedure, the amount of retrofit (required number of dampers) is estimated from the capacity curve of the building before retrofit and allowable story drift of the building. In combining the capacity curves of the building and the dampers, the deformation demand for the dampers can be easily checked against their deformation capacity. The equations to transform the device displacement to roof displacement for the combination of capacity curves are developed. The proposed procedure was applied to the seismic retrofit design of sample buildings. The study found that the estimated capacity curve was very close to the actual capacity curve obtained from the pushover analysis, which can determine an appropriate configuration to meet the required seismic performance.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.3
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• pp.33-40
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• 2012

At present, the problem to secure seismic resistance capacity is one of the most important issue in school buildings. However, the range of facilities to consider retrofit or the proper direction of seismic retrofit haven't provided in details. Therefore in this study, a series of school buildings were chosen as established time, and the structure composition and the seismic performance of the school buildings were investigated to get the comprehensive features of seismic resistance capacity in school buildings. At result, it was presented that the member capacities were less than criteria and structure system was showed the brittle behavior at the collapse prevention level at the school buildings before 1990 year. At the school buildings after 1990 year, though it is hard to get general features for various compositions, it was presented that they have problems for seismic performance evaluation in some buildings at life safety level, specially in the direction of X axis. So, considering the introduction process of seismic criteria in Korea, the school buildings before 2005 year should be examined for seismic resistance capacity and the seismic performance should be examined as well as member capacity to resist seismic.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.267-274
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• 2000

Current seismic design codes for building structures are based on the method which can provide enough capacity to satisfy objected performance level and exactly evaluate the seismic performance of buildings. The capacity spectrum method using the nonlinear static(pushover) analysis is becoming a popular tool for evaluating the seismic performance of existing and new building structures. By means of a graphical procedure capacity spectrum method esimates the performance level of structure by comparing the capacity of structure with the demand of earthquake ground motion on the structure. In the method the relation between base shear estimated by a nonlinear static analysis and horizontal displacement is used. Capacity spectrum is usually expressed as what represent the responses of the equivalent single degree of freedom (ESDOF) system for the building structures. However there are some problems in converting procedures into ESDOF system which include not considering the effect of higher modes of structures. The objective of this paper is to compare and verify existing methods and suggest the modified capacity spectrum for seismic performance evaluation of building structures.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.217-222
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• 2007

An Emergency Diesel Generator (EDG) is one of the safety related equipments of a Nuclear Power Plant. The seismic capacity of an EDG in nuclear power plants influences the seismic safety of the plants significantly. A recent study showed that the increase of the seismic capacity of the EDG could reduce the core damage frequency (CDF) remarkably. It is known that the major failure mode of the EDG is a concrete coning failure due to a pulling out of the anchor bolts. The use of base isolators instead of anchor bolts can increase the seismic capacity of the EDG without any major problems. This study introduces a seismic risk analysis method and presents sample results about the seismically isolated and conventional EDG system.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.14 no.2
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• pp.11-15
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• 2018

A development plan for seismic capacity verification procedures of nuclear components based on the elastic-plastic strain (EPS) features is explained in this paper. The EPS methodology is more realistic to assess seismic responses of components to extreme seismic events beyond the safe shutdown earthquake (SSE) than current practices with the criteria of stress limits. The EPS based approach to analyze the seismic capacity of components can reduce over-conservatism in the current stress-based criteria and can incorporate the seismic responses of components deformed in plastic behavior by the motion of extreme earthquake.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.453-460
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• 2001

The seismic capacity of columns usually has been tested in uniaxial loading condition. The seismic performance used to be evaluated under the same assumption. Since the real earthquake motion is multi-directional, the effects of multi-directional excitation on the seismic capacity of structures need to be carefully examined. In this paper, a frequency dependent alternate biaxial cyclic loading test is proposed as an evaluation method of seismic capacity under multi-directional excitation. Four test specimens were made and tested to study the degradation of strength, stiffness and ductility under biaxial loading condition. A multi- directional excitation. The capacity is obtained using frequency dependent alternate biaxial cyclic loading test. The orthogonal effect is taken into account by increasing the demand.

• Earthquakes and Structures
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• v.10 no.5
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• pp.1111-1123
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• 2016

To study seismic performance of steel frame-bent structure, one specimen with one-tenth scale, three-bay, and five-story was tested under reversed cyclic lateral load. The entire loading process and failure mode were observed, and the seismic performance indexes including hysteretic loops, skeleton curve, ductility, load bearing capacity, drift ratio, energy dissipation capacity and stiffness degradation were analyzed. The results show that the steel frame-bent structure has good seismic performance. And the ductility and the energy dissipation capacity were good, the hysteresis loops were in spindle shape, which shape were full and had larger area. The ultimate elastic-plastic drift ratio is larger than the limit value specified by seismic code, showing the high capacity of collapse resistance. It can be helpful to design this kind of structure in high-risk seismic zone.