해양운송을 위한 플로트오버 설치에서의 로드아웃 보조 프레임의 구조 최적화

Abstract

To install offshore platform topsides that can weigh over 15,000 tons, one of the best practices is utilizing the float-over installation method, which utilizes transportation vessel ballasting and custom support frames to lay the topside over the supporting structure at the installation site. When the float-over installation method is employed, the topside is fully constructed in the yard over load-out support frame (LSF), and is loaded out to the transportation vessel using LSF along with devices such as jack strand, once the construction is finished. Then, the topside over LSF is transported to the installation site for float-over installation through the vessel. In these processes, the LSF should carry thewhole weight of the topside to the ground during load-out process and to the deck of the transportation vessel through a grillage structure, which further distribute the weight over the deck of the transportation vessel during the later stage of the load-out process and during transportation and installation until the weight of the topside is transferred to the supporting structure during operation in offshore site. Since the transportation can take up to 2 months in the ocean, the reliability of the LSF against dynamic stability and fatigue is of critical importance. To ensure reliability of the LSF, the design of the LSF was optimized against dynamic instability and structural fatigue using number of differen