Experimental analysis of dynamic response of floatover installation using rapid transfer technique in continuous load transfer process

Abstract

This study presents the experimental analysis of an innovative floatover installation method with the rapid transfer technique, in which the topside loads can be transferred fast and safely. In the rapid transfer process, 30% loads were firstly transferred onto the jackets within only 1 min using the jacking system. Then both the ballast system and the jacking system were employed to gradually transfer the loads onto the jackets. After 70% topside loads were transferred, the jacking system quickly offloads the remaining 30% loads within 1 min. The continuous load transfer operation was simulated in model tests. The complex motions of the barge and the topside as well as the loads on the Deck Support Unite (DSU) and the Leg Mating Unite (LMU) were analyzed. The maximum and minimum motions of the barge and the topside were statistically analyzed as well as DSU and LMU loads. Results indicate the barge pitch motions largely synchronize with the topside pitch before the second jack-down operation. The barge moved forward a little distance after twice jack-down operations. Results indicate DSU loads varied significantly during the jack-down operations and the jacking system should be designed to provide lateral restraints equivalent to 20% of the topside weight.