Stabbing system for installing offshore jacket structure and installation method of offshore jacket structure using the same

1 . A stabbing system for installing an offshore jacket structure, wherein the stabbing system is used for fixing a jacket leg of the offshore jacket structure inserted into a seabed-pile, the seabed-pile being pre-inserted into a seabed, the stabbing system comprising:

a stabbing member that is installed on an external surface of the jacket leg and supported by an upper end surface of the seabed-pile when the jacket leg has been inserted into the seabed-pile;

a plurality of vertical grippers that are installed in the stabbing member and operated toward an upper end surface of the seabed-pile to adjust an angle between a longitudinal axis of the jacket leg and a horizontal plane defined by a seabed surface;

a plurality of horizontal grippers that are installed in an outer periphery of the stabbing member and operated toward an external surface of the seabed-pile to fix the jacket leg to the seabed-pile; and

a grouting unit that introduces grout into a space between the jacket leg and the seabed-pile, wherein:

the stabbing member includes a horizontal support plate that is formed in a form of ring plate on the external surface of the jacket leg and seated on the upper end surface of the seabed-pile;

the stabbing member includes a vertical support plate that has a tubular form, is bent in an outer periphery of the horizontal support plate and is connected to a lower part thereof;

each of the vertical grippers are spaced apart from each other at a certain interval in a circumference direction on an upper surface of the horizontal support plate, and a vertical gripper piston is operated toward the upper end surface of the seabed-pile by a vertical hydraulic cylinder, adjusting the angle between the longitudinal axis of the jacket leg and the horizontal plane defined by the seabed surface of the seabed-pile;

each of the horizontal grippers includes an upper horizontal gripper, spaced apart from each other at a certain interval in a circumference direction on an external surface of the vertical support plate so that an orientation of each upper horizontal gripper is perpendicular to an orientation of each vertical gripper, and a first piston is operated toward the external surface of the seabed-pile by a first hydraulic cylinder, fixing the jacket leg to the seabed-pile;

each of the horizontal grippers includes a lower horizontal gripper, spaced apart from each other at a certain interval in a circumference direction on an inner end surface of the jacket leg and a second piston is operated toward an inner surface of the seabed-pile by a second hydraulic cylinder, fixing the jacket leg to the sea-bed pile, wherein an orientation of each lower horizontal gripper is perpendicular to the orientation of each vertical gripper;

the grouting unit is installed inside the jacket leg, and a lower end thereof passes through and is connected to a lower end of the jacket leg, forming a grout pipe through which the grout is introduced into the space between the jacket leg and the seabed-pile after the jacket leg has been fixed inside the seabed-pile;

the grouting unit further includes a grout seal provided between a lower end surface of the jacket leg and the seabed-pile; and

a detachable vertical gripper ring is provided between the horizontal support plate and the each of the vertical grippers to prevent a direct application of stress concentration to the seabed-pile.

2 . An installation method using the stabbing system according to claim 1 to install the offshore jacket structure of claim 1 , the installation method comprising the steps of:

inserting the seabed pile into the seabed;

putting the jacket leg of the jacket structure inside the seabed pile;

seating, on an upper end of the seabed pile, the stabbing member of the stabbing system according to claim 1 , and adjusting the angle between the longitudinal axis of the jacket leg and the horizontal plane defined by the seabed surface of the seabed-pile;

fixing the jacket leg to the seabed-pile by operating each of the upper horizontal grippers of the stabbing system and each of the lower horizontal grippers of the stabbing system; and

introducing the grout into the space between the jacket leg and the seabed-pile through the grouting unit after the jacket leg has been fixed inside the seabed-pile.

3 . The installation method of claim 2 , wherein:

the stabbing system measures a tilt of the jacket leg and controls operations of each of the vertical grippers, each of the upper horizontal grippers and each of the lower horizontal grippers, based on a tilt value representing the measured tilt; and

the stabbing system controls each of the vertical grippers based on the tilt value to adjust the angle between the longitudinal axis of the jacket leg and the horizontal plane defined by the seabed surface of the seabed-pile, and controls operations of each of the upper horizontal grippers and each of the lower horizontal grippers based on a weight of the jacket leg while maintaining horizontality.