Model testing of dynamic characteristics of compliant buoyant towers

Rigorous deepwater wave-basin tests for a series of reduced (1/80) scale model compliant buoyant towers (CBT) have recently been conducted in the Deep-Sea Basin at the National Maritime Research Institute (NMRI) in Tokyo, Japan. The models have been designed to comply with the theoretical conditions of the hydro-elastic similitude. The models are based on a conceptual prototype CBT design suited for the Vincent Field situated on the North West Shelf of Western Australia. The research has been funded by the Australian Research Council. Three parameters, namely, seabed stiffness, additional buoyancy and platform payload, were varied to investigate how each influence the performance of the CBT. Only one portion of the tests conducted at the NMRI is reported here. These include results and findings from free decay and load-deflection tests that were performed to achieve the structure's natural periods, modal dampening factors and the tower's global stiffness. These dynamic characteristics and responses obtained from the tests are compared with their finite element analysis (FEA) counterpart.