Journal of Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회논문집)

Korean Society of Coastal and Ocean Engineers (한국해안·해양공학회)
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Identification of Dynamic Characteristics Using Vibration Measurement Data of Saemangeum Mangyeong Offshore Observation Tower and Numerical Model Updating by Pattern Search Method

새만금 만경해상관측타워의 진동계측자료를 이용한 동특성 분석과 패턴서치 방법에 의한 수치해석모델 개선

  • Park, Sangmin (Coastal Development and Ocean Energy Research Center, Korea Institute of Ocean Science and Technology) ;
  • Yi, Jin-Hak (Coastal Development and Ocean Energy Research Center, Korea Institute of Ocean Science and Technology) ;
  • Cho, Cheol-Ho (Ocean Circulation and Climate Research Center, Korea Institute of Ocean Science and Technology) ;
  • Park, Jin-Soon (Coastal Development and Ocean Energy Research Center, Korea Institute of Ocean Science and Technology)
  • 박상민 (한국해양과학기술원 연안개발.에너지연구센터) ;
  • 이진학 (한국해양과학기술원 연안개발.에너지연구센터) ;
  • 조철호 (한국해양과학기술원 해양순환.기후연구센터) ;
  • 박진순 (한국해양과학기술원 연안개발.에너지연구센터)
  • Received : 2020.07.31
  • Accepted : 2020.09.07
  • Published : 2020.10.31
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Abstract

In the case of small observation towers located at sea, it is necessary to confirm the change in dynamic characteristics due to the influence of environmental loads. In this study, the dynamic characteristics were analyzed and the numerical analysis model was designed through field dynamic response measurement on the Mangyeong Offshore Observation Tower (Mangyeong Tower) located near the Saemangeum Embankment. As a result of the measurement, the natural frequency was found to increase slowly as the tide level is lowered. In addition, it was confirmed that the same mode has two frequencies, which was judged to be a phenomenon in which the natural frequency was partially increased when the pile and the ground contacted by scouring. For numerical analysis, the upper mass, artificial fixity point, scour depth and fluid influences are reflected in the structural characteristics of the Mangyeong Tower. In addition, the model updating from the estimated natural frequency and pattern search algorithm was performed. From the model updating, it is expected that it can be applied to future studies on stability of Mangyeong Tower.

해상에 설치된 관측타워에 미치는 환경 하중 변화에 따른 구조물의 동특성 파악은 구조물의 안전성 평가에 중요한 인자로 활용되고 있다. 이 연구에서는 새만금 방조제 인근에 위치한 만경해상관측타워(이하 만경타워) 구조물에 대한 현장계측실험을 통하여 동특성을 분석하고 수치해석모델을 구성하였다. 계측실험 결과, 조위가 하강할수록 고유주파수는 증가하는 추세를 보였다. 또한 동일한 모드가 2개의 주파수를 갖는 것을 확인하였으며, 이는 세굴에 의하여 파일과 지반이 접촉 시에 고유주파수가 일부 증가하는 현상으로 판단되었다. 수치해석을 위하여 구조물의 상부 질량, 가상고정점, 세굴 깊이 및 유체 영향을 고려한 부가 질량 등을 만경타워의 구조적 특성으로 반영하였으며, 추정된 고유주파수 및 패턴서치 알고리즘으로부터 수치해석모델에 대한 모델 개선 작업을 수행하였다. 개선된 해석모델로부터 추후 만경타워에 대한 안정성 검토 측면에서의 연구에 적용될 수 있을 것으로 기대된다.

Keywords

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