JPS6054455B2 - How to join the legs of an elevating offshore work platform - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining legs of an elevating offshore work platform.

The elevating type offshore work platform supports the main body with its legs erected offshore.

Previously, the legs were completely finished and assembled into the main body at the construction site, and the main body was then towed to the site. However, if a strait is bridged while being towed to the site, the legs may run into restrictions on leg height or water depth, and the legs may have to be amputated. In such cases, they are joined on-site after passing through the strait. Therefore, recently, a method has been considered in which the legs are separated in advance, constructed, and then the upper parts of the legs are transported separately and joined on-site. In this case, the upper part of the leg was lifted using a floating crane or the crane of the elevating offshore work platform itself. In other words, a floating crane is used when the amount of leg to be cut is small and the upper part of a long leg is handled.
In this case, a huge floating crane is required due to the weight and height of the upper legs. In addition, when a large amount of legs are to be cut and short leg tops are to be cut, the crane of the elevating offshore work platform itself is used, but in this case, the connection work (welding points) is difficult because the leg tops are cut into pieces. The connection costs will increase significantly and the connection costs will be enormous.
The present invention provides a method for joining the legs of an elevating offshore work platform that can solve the above-mentioned problems. Separately transport it to a designated location, submerge the lower leg in water, bring the offshore work platform above the lower leg, and wind up the floating rope connected to the top of the lower leg onto the offshore work platform via the legwell. insert the upper end of the lower leg into the legwell, connect the upper end of the lower leg to the lower end of the upper leg, pull up the upper leg and the lower leg, and join the upper leg and lower leg to each other on the offshore work platform. It's about letting people know.

According to this method, since the legs are divided into two parts and not cut into pieces, the connection work can be carried out at low cost, and the lower part of the leg and the upper part of the leg can be easily joined without using a crane. An embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, reference numeral 1 denotes an elevating offshore work platform, which is transported to the site by a transport vessel 5. The offshore work platform 1 includes a platform-like main body 2, a jack house 3 disposed at a plurality of locations on the main body 2, and a lower part supported by a jack device (not shown) in the jack house 3. It is composed of a leg upper part 4. 6 is a barge that transports the lower leg 7; 8 is a floating body installed on the lower leg 7; when the lower leg 7 is thrown into the sea, the lower leg 7 is submerged under the weight of the lower leg 7; However, the underwater load of the lower leg 7 in the water is extremely small, and the lower leg 7 is made to stand upright on the seabed.

Reference numeral 9 denotes a set of three pendant wires whose one end is connected to the connecting rod 11 in the upper end of each leg pipe 10 of the lower leg portion 7, and the other end is connected to the wire 12. Reference numeral 13 is a lifting wire whose one end is wound around the winding drum of the winch device on the offshore workbench 1 and whose other end is inserted through the legwell 14, and a wire 15 is connected to the other end.

Reference numeral 16 is an alignment jig whose upper part is inserted and fixed into the lower end of each leg pipe 17 of the leg upper part 4, and whose lower outer peripheral surface is a tapered surface 16A with a downward convergence, and a through hole in the center that runs in the vertical direction. 18.

Reference numeral 19 denotes a rack fixed to the outer peripheral surfaces of the leg pipes 10 and 17.

Note that the alignment jig 16 is provided with an auto-lock device (not shown). The operation of the above configuration will be explained.

That is, as shown in FIG. 1, the elevating offshore work platform 1 has its main body 2 placed on a carrier ship 5, and is transported to the site with the raised leg upper parts 4 supported by the jack house 3. Further, the barge 6 on which the lower leg part 7 is placed is also transported to the site in the same manner as 5. After arriving at the site, when the lower leg 7 is lowered from the barge 6 to the sea, the lower leg 9 is submerged in the water, lands on the bottom, and is raised upright by the floating body 8. Further, the carrier ship 5 is submerged and the main body 2 is made to float, and then the carrier ship 5
Pull it out, but let it sail like J. Next, as shown in FIG. 2, move the offshore work platform 1 above the lower leg 7 and
, 15 are connected to each other. Next, the winch device is activated to wind up the lifting wire 13 and draw the pendant wire 9 into the legwell 14. Next, one end of each pendant wire 9 is passed through the through hole 18 of the alignment jig 16 and into each leg pipe 17, pulled up onto the offshore workbench 1, and wound around the winding drum of the winch device. Next, when the winch device is activated, the lower leg 7 is pulled up via the pendant wire 9, and as shown by the imaginary line in FIG.
The upper end of each leg pipe 10 fits into each centering jig 16,
The lower leg portion 7 and the upper leg portion 4 are connected to each other by the automatic locking device. Next, the upper leg portion 4 and the lower leg portion 7 are pulled up via the rack 19 using a jack device, and the connection portion between the lower leg portion 4 and the lower leg portion 7 is welded. As described above, according to the method for joining the legs of an elevating offshore work platform according to the present invention, since the legs are divided into two parts and are not cut into pieces, the joining work can be carried out at low cost. Since the upper end thereof is inserted into the leg well and the upper end of the lower leg is connected to the lower end of the upper leg, the lower leg and the upper leg can be joined without using a crane.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, in which Fig. 1 is a side view during transportation, Fig. 2 is a side view when the legs are connected, Fig. 3 is a perspective view when the legs are connected, and Fig. 4 is a side view when the legs are connected. FIG. 1... Liftable offshore work platform, 4... Upper leg, 5... Transport vessel, 6... Barge, 7...
...lower leg, 9...
．． →←A pendant wire, 12・
...fi, 16...heart.

Claims (1)

[Claims] 1. The elevating offshore work platform with the upper leg and the lower leg were separately transported to a designated location, the lower leg was submerged in water, the offshore work platform was brought above the lower leg, and the platform was connected to the upper part of the lower leg. Wind up the wire with the buoy onto the offshore workbench via the legwell, fit the upper end of the lower leg into the legwell,
A leg for an elevating offshore work platform, characterized in that the upper end of the lower leg is connected to the lower end of the upper leg, the upper leg and the lower leg are pulled up, and the upper and lower legs are joined to each other on the offshore work platform. Joining method.