Model design and testing of a large gravity-base offshore structure

This paper describes the design of a hydrodynamically scaled model of a Gravity Base Structure (GBS) for testing in wave loading. The measurement and interpretation of the loads is potentially complicated by the dynamic response of the model and its force transducers. A finite-element model of the setup was used to simulate structural response to wave loading and subsequently identify the optimum position of force transducers to measure large global loads without loss of sensitivity/ Furthermore natural frequencies of the model were calculated. The model design required a seal to prevent pressure forces from occurring underneath or inside the model. The seal was constructed and tested to determine stiffness, hysteresis effects, and damping characteristics for small deflections. Static offset and vibration decay tests were performed on the model assembly with and without the seals attached to determine the stiffness and damping effects.NRC publication: Ye