| 摘要 |
<p>A process and apparatus for installing the enbloc superstructure of an offshore platform on the fixed legs emerging from water of the lower structure or jacket including loading the whole superstructure on a vertically movable support platform provided on the deck of a semisubmersible raft or barge, completely submerging the raft in the vicinity of the jacket, the stability being maintained by vertical buoyancy tanks on the raft deck, and lifting the support platform and the superstructure by activating related hydraulic lift cylinders, to a height higher than that of the protruding ends of the jacket leg, independently from wave-motion of sea. Subsequently, cylindrical lift pillars slide, by means of hydropneumatic jacks, within tubular columns provided in the superstructure until the conical ends of the pillars enter corresponding seats in the jacket legs and, during a moment of smooth sea, the superstructure is lifted to the desired height using the hydropneumatic jacks, while at the same time, the support platform is rapidly lowered, and the raft is ballasted.</p> |
