Seaquake Loads Acting on Offshore Wind Turbine

In this paper, we will discuss the effects of seaquake loads acting on offshore wind turbine in case of earthquake. It may be assumed that offshore structures are generally free from the effects of earthquakes. However, even floating structures can be subjected to serious shock by earthquake induced waves which propagate through sea water. This phenomenon is called seaquake, and caused by compressibility of the sea water. The effects of seaquakes acting on the float of offshore wind turbine have to be considered to ensure the safety in earthquakes which occur at the bottom of the sea. In this study, seaquake load acting on the float of wind turbine is simulated by using Boundary Element Method. Helmholtz equation which dominates compressible fluid is solved in the frequency domain. The calculation results in both 2-dimensional and 3-dimensional domains are compared to understand qualitative behavior of seaquake. After understanding the basic characteristics of seaquake loads, the load effects on TLP (Tension Leg Platform) type of offshore wind turbine are discussed. A design flow of TLP type offshore wind turbine is reviewed, considering the effects of seaquake.