KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Modal Parameter Extraction of Seohae Cable-stayed Bridge : II. Natural Frequency and Damping Ratio

서해대교 사장교의 동특성 추출 : II. 고유진동수와 감쇠비

  • 김병화 (경남대학교 토목공학과) ;
  • 박종칠 (한국도로공사 도로교통연구원)
  • Received : 2008.01.22
  • Accepted : 2008.07.09
  • Published : 2008.09.30
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Abstract

This paper introduces a new technique that can extract natural frequencies and damping ratios from output-only vibration data. Firstly, the free vibration data is obtained from the cross correlations of the output-only response data using a singular value decomposition process. Secondly, the well-known system identification algorithm is applied to extract the natural frequencies and damping ratios from the extracted free vibration data. Comparing to ERADC technique, the accuracy of the proposed modal parameter identification algorithm has been numerically examined. Furthermore, the practicability of the proposed algorithm has been examined through the output-only acceleration data collected from the Seohae cable-stayed bridge. Using the proposed technique, total 24 modes have been identified for the deck plate motions of the bridge.

본 논문은 상시진동데이터로부터 구조물의 고유진동수 및 감쇠비를 추정하는 기법을 소개한다. 제안된 기법은 TDD기법에서 추출된 모드형상과 상호상관신호로부터 직교 잡음이 제거된 자유진동함수를 추출하고 시스템 인식기술을 적용하여서 각 모드별 고유진동수와 감쇠비를 추정한다. 제안 알고리즘의 정확도는 수치적으로 기존의 기법과 비교분석 되었다. 제안 알고리즘의 현장 적용성 검토는 서해대교 보강형의 수직방향 가속도에 대한 상시진동데이터를 통하여 검증되었으며, 총 24개의 저차모드가 추출되었다.

Keywords

References

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