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Dynamic Properties of a Lowrise Masonry-infilled RC Frame Building Before and After Seismic Retrofit

저층 조적채움벽 철근콘크리트 골조의 내진보강 전후 동특성 변화

  • 유은종 (한양대학교 건축공학부) ;
  • 김민재 (한양대학교 건축공학부) ;
  • 김승남 (창민우 구조컨설턴트) ;
  • 김지영 (대우건설 기술연구원) ;
  • 최기선 (한국건설기술연구원 건축도시연구소)
  • Received : 2015.03.17
  • Accepted : 2015.04.13
  • Published : 2015.06.30

Abstract

In this study, a series of forced vibration testing and ambient vibration measurement were performed at a lowrise masonry-infilled reinforced concrete frame structure before and after seismic retrofit and its dynamic properties were extracted using system identification techniques. Also, analytical models which show similar dynamic properties to the measures ones were constructed. The system identification results showed that damping ratios in x direction along which the dampers were installed has been increased. From the comparison between the analytical models, the effective stiffness of post-installed member and post-reinforced members(shear walls and damper frames) were only 50% of gross sectional stiffness of the members, which indicates that the these members were not fully integrated with the existing structure or members. In addition, support condition of post-installed footing has to be pinned in y direction to match the dynamic properties, which is seemingly caused by the change of fixity of the soil due to the installation of new footing.

본 연구에서는 저층 조적채움벽 철근콘크리트 골조 구조물의 내진보강 전과 후에 대하여 강제 진동 실험과 상시 진동 계측을 수행하였으며 시스템 식별과정을 통하여 구조물의 동특성을 구하고 해당 구조물과 유사한 동특성을 보이는 해석 모델을 만들었다. 시스템 식별 결과 댐퍼가 설치된 x방향의 감쇠비가 증가되었으며, 해석 모델과 비교한 결과 추가 설치된 부재들(전단벽과 댐퍼)의 유효 강성은 부재의 총단면 강성의 50%만이 발현되어 해당 부재들이 기존의 구조물이나 부재와 완전히 일체화되지는 않음을 알 수 있었다. 또한, 추가 설치된 기초의 y방향 구속조건을 핀으로 하여야 동특성을 일치시킬 수 있었는데, 이는 새로운 기초가 설치되며 해당 지질의 특성이 변화되었기 때문으로 보인다.

Keywords

Acknowledgement

Supported by : 국토교통과학기술진흥원, 국토교통부

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