Simple Pile-Soil Interaction Effect on Seismic Response of Fixed Offshore Platforms

In this paper effect of pile-soil consideration in obtaining seismic response offshore structure is assessed due to earthquake loading. InducedSeismic force is one of the most important excitations for the dynamic response of an offshore structure. According to API, Seismic forces should be accounted in platform design for seismically active regions in order to determine the allowable seismic risk for the type of operation intended. Two model were developed, in the first one, pile-soil interaction was neglected whereas in the second one, pile-soil interaction was considered by using un-grouted pile stubs. The models that were used in this research were consist of two dimensional finite element models with linear behavior. After obtaining dynamic specification of structural system, a linear time history analysis was performed on both models and eventually the response of structure in the form of overall drift and maximum top displacement was compered. Finally it was shown that neglecting consideration of pile soil interaction will not always result in ensuring structural responses.