Structural seismic performance of the Fuel-Oil Unloading Platform located in the BP Gemlik Facility was determined under operational loads and site specific seismic loads. Analysis was performed according to the up-to-date international and local codes using the Non-Linear Time History Analysis Method. Displacement demand and damage level of the structure were determined and their compliance with the codes’ acceptance criteria was checked. Potential risks that a possible earthquake may cause on the platform bridge and the pipelines were also assessed. In-situ ultrasonic testing was performed by divers to determine the corrosion level on steel piles of the platform structure.