• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.9-17
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• 2004

The seismic performance evaluation and retrofit process are very important in old existing bridges. If the result is not appropriate. then a retrofit process are required. Among various retrofit methods, the seismic isolation is a very useful method. because it can be applied by replacing old bridge bearings. In this study, the effectiveness of seismic isolation is rationally verified. For this purpose, two seismic isolations used widely are selected and non-linear static and dynamic analyses are performed. The responses of existing bridges are compared with those of retrofited bridges by seismic isolation bridge for earthquake of target level. and seismic performances are evaluated.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.439-444
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• 2019

In this paper, the seismic performance evaluation of the subway lines 1~4 conducted from April 2010 to October 2013 for the existing structures that were not seismically designed based on the seismic design criteria of urban railways was studied. The detailed design of seismic reinforcement for the facilities requiring seismic reinforcement was summarized through the detailed design of the seismic reinforcement construction conducted from March to December 2018. As a result of the evaluation, 53.2km (total project cost of 322 billion won) of 141.5km of Lines 1~4 were considered to require seismic reinforcement, and finally, the company aims to secure a 100% earthquake-proof rate to withstand earthquake-scale 6.5 by 2020. This paper can be used as basic research data to evaluate and reinforce seismic performance of urban railways in the future.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.474-477
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• 2011

본 논문에서는 내진보강공법의 내진성능향상을 평가하기 위하여 진동대실험을 실시하였다. 실험 구조체는 비보강, 보강 구조체로 각각 실규모 크기의 구조체를 2개 제작하였다. 기둥 상, 중, 하부 및 보에 각각 Strain게이지, 가속도계를 설치한 후 설계펙트럼가속도 0.15g의 30~150%까지 가속도를 증가 시키면서 실험을 수행하였다. 그 결과 비 보강 구조체는 0.2g에서 최대 80cm균열이 발생하였으나 보강 구조체는 균열이 발생하지 않았다. Strain의 변화량에서는 비 보강이 보강보다 최대 1700%크게 나타났다. 가속도의 변화량은 비 보강이 176%크게 나타났다. 진동대 실험결과 본 내진보강공법이 내진성능향상에 지대한 영향을 주고 있음이 증명되었다.

• Nuclear industry
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• v.37 no.1
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• pp.7-14
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• 2017

작년 경주 지진으로 원자력 안전에 대한 시민들의 촉각이 예민해져 있는 가운데 최근 대전 지역에서 원자력연구원의 하나로 원자로 건물 외벽 내진 보강 공사 방식에 대한 검증을 요구하는 여론이 일고 있다. 그 동안 원자력연구원에서 진행한 하나로 건물 내진 보강 공사 배경과 주요 일정, 설계 개념, 구조 성능 검증 실험, 공사 현황, 건물 성능 점검, 안전 관리, 정보 공개 및 검증, 향후 계획 등을 정리하여 종합했다.

• Computational Structural Engineering
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• v.26 no.2
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• pp.37-42
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• 2013

준공 후 상당한 시간이 지나 내진설계가 되지 않았거나 내진상세가 이루어지지 않은 건물의 부족한 내진성능을 보완하기 위한 방법의 하나로 좌굴이 제한된 가새형 댐퍼를 적용할 수 있다. 이 방법을 적용할 경우, 기존 내진보강법의 불확실성을 줄일 수 있었음에도 불구하고, 댐퍼의 설계과정이 복잡하여 실무에 적용하기 어려웠다. 그러나 본 원고에서는 강성과 강도개념을 적용한 댐퍼의 설계법을 적용함으로써, 실무에서 쉽게 적용할 수 있도록 하였다. 준공된 지 16년이 지난 비틀림 비정형 건물에 대한 내진성능을 평가한 후, 가새형 댐퍼로 보강한 결과는 다음과 같다. (1) 일방향해석결과 나타난 골조별 하중-지붕변위의 관계를 이용하여, 연약골조의 강성을 강한 골조의 강성과 일치시키고, 이 강성비로부터 댐퍼가 부담하는 최적의 내력비율을 정하여 내진보강을 수행한 결과, 가새를 설치한 방향으로는 가새형댐퍼가 비틀림 방지와 연성증대효과를 구조물에 부여하여 성능이 획기적으로 증가하였다. 또한, 그 가새의 직각방향 하중에 대해서도 가새를 설치함으로써 비틀림 강성이 증가하고, 가새와 코어벽체가 인장과 압축으로 횡력에 저항하여 횡저항 성능이 증가하였다. (2) 내진성능이 부족한 비틀림 비정형 건물의 내진성능을 증진시키기 위해 가새형 댐퍼를 적용함에 있어, 댐퍼의 강성을 이용하여 구조체의 비틀림 거동을 최소화하고, 연성을 증진시키는 방법을 체택할 경우, 실무자들이 보다 쉽게 적용할 수 있으면서 그 효과도 상당히 클 것으로 기대된다.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.343-350
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• 2009

In the present study, a new seismic retrofitting method that employs both a stainless steel wire mesh and a permeable polymer concrete mortar was proposed for reinforced concrete bridge piers with nonseismic design details. For this purpose, a total of six nonseismically designed bridge piers were tested under lateral load reversals. The test results reveal that nonseismically designed piers with lap splices need to be retrofitted to resist earthquake induced forces. In addition, it was proven that the proposed retrofitting method can be useful in improving the strength, stiffness, and energy dissipation capacities of bridge piers designed nonseismically. It is thus expected that the proposed method may provide an improved ductility capacity without sudden softening of strength for bridge piers excursing inelastic displacement range.

• Land and Housing Review
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• v.1 no.1
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• pp.43-50
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• 2010

In this study, the influences of steel dampers on the behavior of RC frames were investigated using the experimental approach to suggest the installation methods of steel dampers using K-barces. The performances of RC frames with dampers can be evaluated by superposition the load-displacement curves of RC frames and steel dampers with regard to the influences of K-braces. Three specimens are tested to investigate the cyclic behavior of RC frames with dampers. The performances of RC frames with dampers with respect to strength, rigidity, and hysteretic performance are examined. It was found that test results demonstrates the effect of seismic retrofit on RC frames with steel dampers(D-RCF-KBSF, D-RCF-KBSP) compared with RC frames(N-RCF). An approximate design curves may not be good agreement with those of the tests, it is conservative enough so that you can design of RC frames with steel damper with regard to the influences of K-braces.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.131-142
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• 2021

For old piers constructed when seismic design code had not been developed, lap splices usually exist in plastic hinge region. Corrosion of rebars causes decreasement in cross-sectional area of rebar and deterioration of lap-splice behaviour, thereby reducing the seismic performance of the old piers. In this research, according to these characteristics of old piers, test specimens are designed and manufactured considering rebar corrosion, lap splice, seismic design details, and seismic reinforcement. These effects are investigated through experiments. As a result of these experiment, rebar corrosion as well as lap splice reduces displacement ductility. When seismic design details or steel-plate reinforcement are applied, sufficient displacement ductility is expressed. For non-seismically designed specimens, loosening of the lap splice of transverse rebars caused buckling of longitudinal rebars and crushing of core concrete in plastic hinge region . For seismically designed specimen, area-reducing and untying of transverse rebars due to corrosion of rebars caused buckling of longitudinal rebars and crushing of core concrete.

• Journal of Korean Society of societal Security
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• v.2 no.2
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• pp.63-68
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• 2009

Seismic design of newly built bridges can be considered and carried out during construction process according to the revised road bridge design standard issued recently. While for the existing reinforced concrete bridge priers under service before new standard implements, their resistance capacity against lateral seismic loading is inferior. In this research, seismic reinforcing for existing bridge piers by nickel-chrome alloy bar has been analyzed. Based on the established model by MIDAS program, the behaviors of bridge piers including deformation and stress with and without nickel-chrome alloy reinforcing bars have been compared and discussed under lateral seismic loading. And the advantages of using nickel-chrome alloy bar as seismic reinforcement over other materials, such as good performance, good economy etc. have been demonstrated by comparison with other researches. Also the anti-seismic efficiency of nickel-chrome alloy reinforcing bars has been confirmed by MIDAS modeling analysis.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.49-57
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• 2010

This study is the research appling the representative Displacement-Based Design which is the basic concept of Direct Displacement Based Design proposed by Chopra and Goel to original Reinforced Concrete structure and determining the thickness of retrofit Steel Jacket about the Maximum design ground acceleration, and developing the more improved Algorithm as well as program by the Retrofit Design method and Nonlinear analysis by the Performance design method before and after reinforcement appling the determined retrofit thickness. To predict the target displacement of retrofitted columns, a nonlinear analysis model of reinforced concrete columns has been developed to be based on the nonlinear fiber cross-sectional and segmental analysis model, and the seismic displacement level of retrofitted columns is estimated by two procedures, the direct displacement-based design method and the displacement coefficient method. In examples of seismic retrofit design, the current seismic improved design method gives good results in improvements of displacement levels and displacement ductilities of retrofitted columns.