JPH025852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a prefabricated steel sheet pile cell assembly apparatus, and particularly to a prefabricated steel sheet pile cell assembly method using a floater pontoon.

In the conventional prefabricated steel sheet pile cell construction method, the cells are assembled in a yard on land or at a location at sea with favorable sea conditions, then hoisted to the site by a crane ship, transported, and driven into place. However, when assembling on land, you need a yard with a waterline where a crane ship can approach to lift it later.
It is difficult to find a place like this.

Therefore, two methods are generally used: a method of assembling using a special barge, and a method of building an assembly guiding frame underwater and assembling it there.

However, this conventional method has drawbacks as shown below.

(a) Method using a dedicated barge for prefabricated cell assembly This method involves assembling and pouring the cells on a dedicated barge, but the turnover rate is low considering the large equipment, and if the construction is permanent, the construction cost may be lower. However, when ordering spot work, the utilization rate of dedicated barges is low and the assembly costs are relatively high.

(b) Method of installing guide frames on the sea This is a construction method in which piles are driven on the seabed at an appropriate depth, and using this as a foundation, guide frames are built on top of this and sheet piles are inserted to form cells. A calm body of water of appropriate size and depth is required nearby, and if the prefabricated cell is assembled far from the construction site, it will be necessary to transport the prefabricated cell by hoisting it on a crane ship, which may cause stability problems. Problems arise in economic efficiency, construction period, etc.

After a prefabricated cell is assembled, in order to move it, it must be suspended by a crane ship to a height that exceeds the guide frame, and this is a factor that determines the size of the crane ship. In other words, the size of the crane ship depends more on the lifting height and reach than on the lifting load, and the construction cost increases accordingly.

All of the work, including pile driving and installation of guide frames, will be carried out both offshore and on-site, so the construction period will be relatively long.

There is not enough temporary scaffolding when installing the driving device.

The method of assembling a prefabricated steel sheet pile cell according to the present invention is designed to eliminate these drawbacks, and involves suspending a weight from a floater pontoon whose buoyancy can be freely adjusted. a step of providing a guide frame for assembling a prefabricated steel sheet pile cell on the side surface of the floater pontoon, a step of assembling the steel sheet pile cell using this guide frame, and a step of reducing the buoyancy of the floater pontoon. The method is characterized by comprising a step of adjusting the steel sheet pile cell so that it is submerged on the seabed, and a step of lifting and transporting the steel sheet pile cell.

The second aspect of the prefabricated steel sheet pile cell assembly method of the present invention is the step of suspending a weight from a floater pontoon whose buoyancy can be adjusted so that the floater pontoon is slightly submerged below the sea surface; A step of providing a guide frame for assembling a prefabricated steel sheet pile cell on the side of a floater pontoon, a step of assembling a steel sheet pile cell using this guide frame, a step of connecting the steel sheet pile cell and the floater pontoon, and removing the weight. and a step of transporting the connected steel sheet pile cell and floater pontoon.

Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, a floater pontoon 1 whose buoyancy can be freely adjusted by injecting water.
A weight 3 is suspended from the lower surface of the floater pontoon 1 via a wire 2, and the floater pontoon 1 is held in a state in which it is sunk somewhat below the sea surface against the buoyancy of the floater pontoon. A cylindrical guide frame 5 for assembling the prefabricated steel sheet pile cell is attached via the guide frame 5, and the steel sheet pile cell 6 is assembled using this guide frame 5.

Since the assembly method of the present invention is as described above, the position of the floater pontoon 1 hardly changes even when the tide level fluctuates, that is, the position of the floater pontoon 1 is as shown in Fig. 1 at low tide and as shown in Fig. 3 at high tide. The height of the floater pontoon 1 from the seabed hardly changes, and the steel sheet pile cells 6 can be assembled very easily.

After assembling the steel sheet pile cell 6, as shown in FIG. There is a great advantage that the lifting height of the sheet pile cell 6 can be made extremely low, and the crane can also be made smaller.

In another embodiment of the method of the present invention, as shown in FIG. 5, the floater pontoon 1 is floated with a seawater ballast 7 inside it, and the steel sheet pile cell 6 is assembled in this state, and then As shown in FIG. 6, the floater pontoon 1 and the steel sheet pile cell 6 are connected by a connecting part 8, and the seawater ballast 7 is connected from the floater pontoon 1 to the steel sheet pile cell 6.
The floater pontoon 1 is floated together with the steel sheet pile cell 6 by draining water, and as shown in FIG. 7, both of them are towed to a predetermined installation location by a tugboat 9 after cutting the wire 2.

As described above, by using the assembly method of the present invention, the drawbacks of the conventional method can be eliminated, and there is a great advantage that steel sheet pile cells can be easily assembled using extremely simple means.

[Brief explanation of drawings]

Figure 1 is a front view for explaining the assembly method of the present invention;
The figure is a plan view, FIGS. 3 and 4 are explanatory diagrams of its operation, and FIGS. 5 to 7 are explanatory diagrams of other usage examples of the present invention. 1...Floater pontoon, 2...Wire,
3... Weight, 4... Support, 5... Guide frame, 6
... steel sheet pile cell, 7 ... seawater ballast, 8 ... connection section, 9 ... tugboat.

Claims (1)

[Scope of Claims] 1. A step of suspending a weight on a floater pontoon whose buoyancy can be adjusted so that the floater pontoon is slightly submerged below the sea surface, and installing prefabricated steel on the side of the floater pontoon. a step of providing a guide frame for assembling a sheet pile cell, a step of assembling a steel sheet pile cell using this guide frame, a step of adjusting the buoyancy of the floater pontoon so that it is submerged on the seabed, and a step of assembling the steel sheet pile cell using the guide frame; A prefabricated steel sheet pile cell assembly method comprising the steps of lifting and transporting the cells. 2. A step in which a weight is suspended from a floater pontoon whose buoyancy can be adjusted to allow the floater pontoon to sink somewhat below the sea surface, and a guide frame for assembling a prefabricated steel sheet pile cell is attached to the side of the floater pontoon. a step of assembling a steel sheet pile cell using this guide frame, a step of connecting the steel sheet pile cell and the floater pontoon and removing the weight, and a step of assembling the steel sheet pile cell and the floater pontoon after the connected steel sheet pile cell and the floater pontoon. A prefabricated steel sheet pile cell assembly method comprising the steps of: