Experimental analysis of hydrodynamic response of the twin-barge floatover installation for mega topsides

Abstract

The twin-barge floatover method can efficiently avoid the high dynamic fender impacts between the jacket and the barges and reduce the costs of the mega topsides installation. This study presents the experimental analysis of the twin-barge floatover installation method. Two identical barges elastically hinged with the topsides by the hemisphere-shaped DSU (Deck Support Unit) are modeled in the tests. Motions of the hinged twin-barge as well as DSU loads in heading, beaming and quartering waves are investigated. Results reveal that the motion behaviors of the twin-barge in heading seas are quite identical. However, for beaming and quartering waves, the shielding effect, together with the hydrodynamic and mechanical interactions, have a great influence on the amplitude and phase-difference of the twin-barge motions. Due to the shielding effect, the windward barge motions are much larger than the leeward barge. The sloshing resonance of the in-between fluid may lead to the large barge motions. The recorded trajectories of the guide pins indicate that the relative long wave will threaten the mating operation as the stabbing pin motions will exceed the capture radius. Comparisons of the response in different wave directions indicate the quartering waves lead to the largest DSU loads.