Response Characteristics of Soft Settled Type of Offshore Structures Subjected to Harmonic Sea Wave and Earthquake Wave

摘要

During an earthquake;;the soft settled type of offshore structures mayrnhave the merit that the horizontal force acting on the structure isrnsmaller than that of the fixed type of structures;;since slip occurs if arnlarge external force exceeding the limited value of frictional resistancernforce developing at the base. In this paper;;a two dimensional rigidrnbody of rectangular section is dealt with for two types of dynamicrnexcitations;;i.e. harmonic surface wave of the sea and earthquake wavernat the sea bed. The influence of the mooring stiffness;;friction at thernbase;;density and depth of the water etc. on the dynamic responses isrninvestigated. From the numerical analysis;;the responses of motion ofrnthe structure;;restoring force and wave force are grasped and therneffective factors to reduce the responses are made clear.