Design and Testing of Scour Protection for Adriatic LNG GBS

The Adriatic LNG terminal is a liquefied natural gas offshore terminal located about 17 km off the coast of Rovigo, Italy in the northern Adriatic, where the water depth is approximately 29 m. Scour protection was needed around the GBS and the mooring dolphins to prevent the bed material under them from washing out. This paper presents a description of the scour protection design for the GBS and the mooring dolphins. The paper will first present the design criteria and the design approach. The dynamic stability approach, which has been developed in the recent years, was applied. This approach allows the profile of the armor rock to deform, but damage (loss of rocks from the scour protection system) must be very limited under the specified design environmental conditions. Particular aspects influencing the design of the scour protection in this case are the use of skirts and the composition of the upper layers of the seabed. The paper will further highlight the way in which existing data and physical modeling were used to arrive at the final design. In particular it will be demonstrated that this is an effective way to carry out the design and that the adaptations of the final design developed and tested during the physical model tests are important. Finally, the paper will present the final design obtained.