심한 조류환경에서의 모노파일식 해상구조물에 대한 진동특성 및 구조손상 평가에 대한 실험적 연구

Abstract

It is very crucial to monitor the structural dynamic characteristics to ensure the structural integrity and serviceability especially for offshore structures under severe environmental conditions because changes in dynamic characteristics such as natural frequencies and modeshapes of a structure are directly associated with structural integrity conditions. Through the previous study on the long-term behavior of the Uldolmok tidal current power plant structure, it was observed that the natural frequencies are fluctuated with a constant period, i.e. approximately twice a day according to the changes of tidal height and tidal current velocity, and also it was reported that the construction work had a lot of trouble especially in connecting jacket support structure and its pile foundation. Therefore there is a necessity to investigate the fundamental reason of the fluctuation of natural frequencies and the relationship between the dynamic properties and the integrity of pile foundation. In this study, a lab-scale experimental study was conducted to investigate the causes of fluctuation of the natural frequencies and the effect of structural damage in foundation using a circulating water channel. Three independent parameters, which might be related to the fluctuation of natural frequencies, were considered in this experimental study including tidal height, tidal current speed and boundary conditions in its foundation. Theuch as natural frequencies and modeshapes of a structure are directly associated with structural integrity conditions. Through the previous study on the long-term behavior of the Uldolmok tidal current power plant structure, it was observed that the natural frequencies are fluctuated with a constant period, i.e. approximately twice a day according to the changes of tidal height and tidal current velocity, and also it was reported that the construction work had a lot of trouble especially in connecting jacket support structure and its pile foundation. Therefore there is a necessity to investigate the fundamental reason of the fluctuation of natural frequencies and the relationship between the dynamic properties and the integrity of pile foundation. In this study, a lab-scale experimental study was conducted to investigate the causes of fluctuation of the natural frequencies and the effect of structural damage in foundation using a circulating water channel. Three independent parameters, which might be related to the fluctuation of natural frequencies, were considered in this experimental study including tidal height, tidal current speed and boundary conditions in its foundation. The