JP2953818B2 - Construction method for deep water structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a structure installed in a deep sea, for example, a foundation for a deep water bridge or an offshore platform.

[0002]

2. Description of the Related Art In recent years, in Japan, bridges and marine platforms have been increasingly constructed in deep waters. For example, the Bisan Seto Bridge, Honshu-Shikoku Bridge, which was opened in 1988, produced a large steel caisson, which was used as a foundation at shipyards, etc. After that, the construction method was adopted in which the top of the shortage was added at the site.

[0003] In addition, a platform for oil and natural gas drilling to be built in the North Sea where the weather and sea conditions are severe, first, the bottom of the platform is manufactured by dry dock,
Launching this from the dry dock, floating the foundation of the structure in a calm sea area at a large water depth such as a fjord in Northern Europe, mooring it, building up the structure in order from the bottom, constructing the structure, It is towed to a 150m site and installed.

[0004]

However, in the method of constructing the substructure of the bridge, the construction period at the site is long, and the structure is exposed to external force for an extended period in an unstable state. However, there is a disadvantage that the temporary equipment becomes large. Further, calm sea areas are required for the construction of the marine platform, but such places are limited all over the world, and it is hard to say that the construction method can be adopted anywhere.

[0005] A steel jacket-type structure is also used as a basic structure of the offshore platform. However, since the structure has low rigidity and a large amount of deformation due to an external force, it becomes a substructure of the bridge. I can't get it. An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a method for assembling a support member constituting a deep water structure by a simple method to build the structure.

[0006]

In order to achieve the above object, the present invention provides a method for manufacturing a supporting member constituting a deep water structure at a place other than an assembling place, and towing it to the final place at sea and assembling it. A method for building a deep water structure comprising submerging on the seabed ground, connecting the tops of two or more support members, balancing the buoyancy of the ballast material and the support members, and assembling into a stepladder shape. This solves the problem.

[0007]

The ballast material is injected from the base portion of the support member that is floating and lying, and two or more support members are vertically or forward inclined at sea to face each other, and at about the same time as the ballast material is injected. , Connecting the tops of the support members. Thus, the support member is opened in the shape of a stepladder, and the structure is sunk on the seabed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the construction method will be described below in the order of each step, taking a bridge pier as an example of a deep water structure. Manufacture of pier members The piers that constitute the substructure are manufactured by dry dock.
The pier is connected between two pillars 10 as shown in FIG.
And a pair of truss-like frames 12 having a ladder shape. The size of each frame 12 is determined by the water depth of the sea area in which it is installed.
It is possible within a range of up to several hundred meters.

For example, a pier installed at a depth of 300 m is a concrete pipe having an outer diameter of 20 m and a height of 320 m.
m, top width 50 m, and leg opening width 150 m. Further, inside the pillar 10, a steel plate partition is provided at intervals of several meters to partition the inside, and an empty room into which a ballast material described later is injected and a pump room for installing a pump for supplying and discharging the ballast material are provided. So that it can be used as

[0010] The tow frame 12 is pulled out of the dry dock, floated on the sea, and floated and towed to the sea area where it is to be installed. In the case of manufacturing with a small-scale dry dock, the frame 12 is divided into a plurality of parts, manufactured, pulled out from the dry dock, joined on a calm sea, and then towed to the final installation location.

Assembling the Structure The frame 12 is assembled in a sea area where the water depth is sufficient, at or near the installation location of the structure. First, a ballast material such as seawater is injected from the base of the frame 12 lying on the sea, and the frame 12 is vertically raised on the sea as shown in step A of FIG. After balancing the buoyancy of the ballast material and the frame 12 so that the pair of frames 12 face each other, as shown in step A, the frames 12 are pulled together and joined. The pulling work is performed by equipment such as a crane ship, tugboat, and winch. Next, the frame 12
The ballast material is partially drained while the top of the frame is connected, and the frame 12 is opened in a predetermined shape using a jack or a tugboat, and the shape is fixed by appropriate fixing means 13 as shown in the process. I do. Reference numeral 14 denotes a wire rope used for a leg opening operation.

Step B of FIG. 1 shows another method of assembling the piers. The piers are adjusted by ballasting so that the pair of frames 12 tilt forward to a predetermined angle, and the crane ship or the like is maintained as it is. (Step B).

Further, FIG. 1C shows a state in which the pair of frames 12 are connected to each other by the hinge mechanism 15 with the tops thereof facing each other while floating on the sea. Subsequently, a ballast material is put in from the base of the frame 12, and the frame
Is shown (step C). At this time, if necessary, wire ropes 14 are connected to both frames 12.
And the ropes 14 are tightened to pull the frames 12 together. Subsequent steps are the same as the above steps.

Although the above three methods have been described, all of these methods connect the tops of the pair of frames 12 and use the buoyancy of the ballast material and the frames 12 to fold the stepladder as if it were a pier. 16 is assembled.

Subsequently, the ballast material is again poured into the assembled frame 12 so that the pier 16 is submerged on the seabed and settled . By injecting the ballast material, the pier 16 gradually penetrates into the seabed ground by its own weight. At this time, the posture of the pier 16 can be controlled by adjusting the water injection amount and the water injection speed. Note that, depending on the state of the seabed ground, a drilling device may be installed in the lower end portion of the pillar 10 in advance, and the seabed ground may be sunk while excavating. Finally, a top plate 17 of a predetermined size is placed on the tops of both frames 12 protruding offshore, and the height and posture of the pier 16 are finally adjusted (step).

Superstructure A superstructure such as a main tower is installed on the top slab 17 in the same manner as a normal bridge construction method.

In the above embodiment, the bridge pier is assembled with a pair of frames. However, the present invention can also be applied to a support member that forms a bridge pier using hollow concrete or steel columns. it can. That is, a combination of the support and the frame 1 or a combination of a plurality of supports is possible.

[0018]

According to the method of constructing a deep water structure according to the present invention, two or more supporting members are connected to each other, and the ballast material and the supporting members are balanced in buoyancy to be assembled into a stepladder shape. Thus, the structure can be built by an extremely simple method. In addition, since all of the support members can be manufactured in the dry dock, the construction period can be shortened and quality control can be performed well as compared with the conventional method that involves many offshore operations.

Further, the present invention provides a method for controlling the amount of water injected into the ballast material, or by modifying the top slab, so that the excavation leveling or sand-filling, which is indispensable for the installation work of ordinary offshore structures, is performed. The work of processing the sea floor, which is called leveling by seawater, becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an assembling / construction order of a pier.

FIG. 2 is a front view of a frame 12 constituting a pier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pillar 11 Digit 12 Frame 13 Fixing means 14 Wire rope 15 Hinge mechanism 16 Bridge pier 17 Top plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI E01D 21/04 (72) Inventor Hidemasa Saka 1-20-40 Sengen, Tsukuba-shi, Ibaraki (56) References JP-A 61-61 172913 (JP, A) JP-A-49-84027 (JP, A) JP-B-47-50820 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02B 17/02 E01D 19 / 02 E01D 21/00 E02B 17/00 E02D 27/32

Claims (1)

(57) [Claims] 1. A structure for a deep water structure, comprising: producing a support member constituting a structure for a deep water at a place other than an assembling place; assembling the support member at sea to a final installation place; A method for building a deep water structure, comprising connecting two or more support members to their tops, balancing the buoyancy of the ballast material and the support members, and assembling the structure into a stepladder shape.