• Title/Summary/Keyword: tidal current power plant jacket structure

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A Case Study on the Foundation Work of Uldolmok Tidal Current Power Plant (울돌목 시험조류발전소의 기초 시공 사례)

  • Kwon, Oh-Jung;Oh, Myoung-Hak;Lee, Kwang-Soo;Park, Jin-Soon
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.610-613
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    • 2009
  • Uldolmok tidal current power plant was constructed on May 2009 at Jindo Gun in Korea. However it had much trouble in installing structure due to the extremely fast tidal current velocity(max. 5.5m/sec) and the jacket type plant structure. Therefore in this paper, The characteristics of tidal current and sea bed topography at Uldolmok tidal current plant site are investigated, and the detailed foundation work process of the plant is described.

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Long-Term Measurement of Static Strains of Jacket Type Offshore Structure under Severe Tidal Current Environments (빠른 조류 환경에서의 재킷식 해양구조물 시공 중 및 운영 중 장기 변형률 계측 및 분석)

  • Yi, Jin-Hak;Park, Jin-Soon;Park, Jun-Seok;Lee, Kwang-Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6A
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    • pp.389-398
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    • 2012
  • In this study, structural strain responses of the jacket-type Uldolmok tidal current power plant structure under severe tidal environments were measured and analyzed using long-term measurement system during construction and also operation. It was observed that there were significant changes in strain responses at the steps of jacket lifting, block loading, pile ejection and insertion. Strains due to dead loads and tidal loads were analyzed before and after removal of a jacket leg, and it was also found that the strains due to dead load were much significantly changed after jacket leg removal. From the measurement data during operation, it was found that strain responses were fluctuated with M2 and M4 tidal periods and also relatively short period of about 10 min due to the peculiar tidal characteristics in the Uldolmok strait. Finally, the neural network-based non-parametric estimation models were investigated to build up the signal-based structural damage monitoring system.

Electromechanical impedance-based long-term SHM for jacket-type tidal current power plant structure

  • Min, Jiyoung;Yi, Jin-Hak;Yun, Chung-Bang
    • Smart Structures and Systems
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    • v.15 no.2
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    • pp.283-297
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    • 2015
  • Jacket-type offshore structures are always exposed to severe environmental conditions such as salt, high speed of current, wave, and wind compared with other onshore structures. In spite of the importance of maintaining the structural integrity for an offshore structure, there are few cases to apply a structural health monitoring (SHM) system in practice. The impedance-based SHM is a kind of local SHM techniques and to date, numerous techniques and algorithms have been proposed for local SHM of real-scale structures. However, it still requires a significant challenge for practical applications to compensate unknown environmental effects and to extract only damage features from impedance signals. In this study, the impedance-based SHM was carried out on a 1/20-scaled model of an Uldolmok current power plant structure in Korea under changes in temperature and transverse loadings. Principal component analysis (PCA)-based approach was applied with a conventional damage index to eliminate environmental changes by removing principal components sensitive to them. Experimental results showed that the proposed approach is an effective tool for long-term SHM under significant environmental changes.

Long Term Monitoring of Dynamic Characteristics of a Jacket-Type Offshore Structure Using Dynamic Tilt Responses and Tidal Effects on Modal Properties (동적 경사 응답을 이용한 재킷식 해양구조물의 장기 동특성 모니터링 및 조류 영향 분석)

  • Yi, Jin-Hak;Park, Jin-Soon;Han, Sang-Hun;Lee, Kwang-Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.2A
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    • pp.97-108
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    • 2012
  • Dynamic responses were measured using long-term monitoring system for Uldolmok tidal current pilot power plant which is one of jacket-type offshore structures. Among the dynamic quantities, the tilt angle was chosen because the low frequency response components can be precisely measured by dynamic tiltmeter, and the natural frequencies and modal damping ratio were successfully identified using proposed LS-FDD (least squared frequency domain decomposition) method. And the effects of tidal height and tidal current velocity on the variation of natural frequencies and modal damping ratios were investigated in time and frequency domain. Also the non-parametric models were tested to model the relationship between tidal conditions and modal properties such as natural frequencies and damping ratios.

Impedance-based Long-term Structural Health Monitoring for Jacket-type Tidal Current Power Plant Structure in Temperature and Load Changes (온도 및 하중 영향을 고려한 임피던스 기반 조류발전용 재킷 구조물의 장기 건전성 모니터링)

  • Min, Jiyoung;Kim, Yucheong;Yun, Chung-Bang;Yi, Jin-Hak
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.5A
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    • pp.351-360
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    • 2011
  • Jacket-type offshore structures are always exposed to severe environmental conditions such as salt, high speed of current, wave, and wind compared with other onshore structures. In spite of the importance of maintaining the structural integrity for offshore structure, there are few cases to apply structural health monitoring (SHM) system in practice. The impedance-based SHM is a kind of local SHM techniques and to date, numerous techniques and algorithms have been proposed for local SHM of real-scale structures. However, it still requires a significant challenge for practical applications to compensate unknown environmental effects and to extract only damage features from impedance signals. In this study, the impedance-based SHM was carried out on a 1/20-scaled model of an Uldolmok current power plant structure under changes in temperature and transverse loadings. Principal component analysis (PCA) was applied using conventional damage index to eliminate principal components sensitive to environmental change. It was found that the proposed PCA-base approach is an effective tool for long-term SHM under significant environmental changes.

Development of a Damage Monitoring Technique for Jacket-type Offshore Structures using Fiber Bragg Grating Sensors (광섬유 브래그 격자 센서를 활용한 재킷식 해양구조물의 손상 감지 기법 개발)

  • Park, Hyun-Jun;Koo, Ki-Young;Yi, Jin-Hak;Yun, Chung-Bang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.6A
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    • pp.399-408
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    • 2011
  • Development of smart sensors for structural health monitoring and damage detection has been advanced remarkably in recent years. Nowadays fiber optic sensors, especially fiber Bragg grating (FBG) sensors, have attracted many researchers' interests for their attractive features, such as multiplexing capability, durability, lightweight, electromagnetic interference immunity. In this paper, a damage detection approach of jacket-type offshore structures by principal component analysis (PCA) technique using FBG sensors are presented. An experimental study for a tidal current power plant structure as one of the jacket-type offshore structures was conducted to investigate the feasibility of the proposed method for damage monitoring. It has been found that the PCA technique can efficiently eliminate environmental effects from measured data by FBG sensors, resulting more damage-sensitive features under various environmental variations.