JP2001097278A - Method for constructing floating body structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for constructing a floating body structure capable of providing a floating body structure with high durability, strong connection at connection parts, and high rigidity by reducing a corrosion with sea water. SOLUTION: Concrete floating bodies 5A and 5B are manufactured on land, connected to each other in the state of being floated on sea, and formed integrally with each other using a steel truss 11 bridged across the upper surfaces of a group of concrete floating bodies connected to each other. Thus, the floating units with high rigidity can be constructed, and a floating body structure 1 can be constructed by connecting the floating body units to each other with these floating body units floated on sea.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for constructing a floating structure.

[0002]

2. Description of the Related Art Making large-scale floating structures such as a floating heliport or a floating airport made of concrete is convenient for reducing corrosion due to seawater and increasing durability, but a steel floating body is used. Since it is much heavier than a structure, it is problematic to construct a floating structure by dividing it into several floating units on the ground and manufacturing it, floating it on the water surface and joining it offshore. .

[0003] That is, in the case of a steel floating structure, since it is lightweight, even if the size of each floating unit is increased and the number of work steps for offshore joining is reduced, there is no problem. In the case of a floating structure, when the size of the floating unit is increased, a huge lifting machine such as a ship crane is required to lower the floating unit manufactured on land to the surface of the water, and the size of the floating unit is reduced. When the weight is reduced to such an extent that it can be lifted by a general crawler crane or the like, the number of floating units increases, and the number of work steps for offshore joining significantly increases.

In order to avoid such inconvenience, if a method of manufacturing a floating unit in a dock is adopted,
Towing work to the construction site is required, and towing is not possible in a closed sea area, and it is necessary to construct a dry dock on the site. In any case, it is very uneconomical.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a floating unit in which at least a portion of the floating unit which comes into contact with seawater is a general crawler. By connecting a plurality of lightweight concrete floating blocks so that they can be lifted by a crane etc., the upper part that does not come in contact with seawater is made of a lightweight and strong steel truss structure, At the same time as reducing corrosion and increasing durability, it is possible to increase the size of the floating unit and reduce the number of work for offshore joining, and to float the vertical dimensions of individual concrete floating blocks on the water surface Method of constructing a floating body structure that makes the connection as strong as possible, while minimizing the size as much as possible There to establish.

[0006]

The technical measures taken by the present invention to solve the above-mentioned problems are as follows. That is, in the method of constructing a floating structure according to the present invention, a concrete floating block is manufactured on land, and the concrete floating blocks are connected to each other while the concrete floating blocks are floating on the sea surface, and are connected. By integrating with a steel truss bridged over the upper surface of the concrete floating block group, a highly rigid floating unit is built, and the floating unit is connected to each other while the floating unit is floating on the sea surface. It is characterized by building.

[0007] According to the above structure, at least a portion of the floating unit that contacts the seawater is formed by connecting a plurality of concrete floating blocks, and an upper portion that does not contact the seawater is lightweight and lightweight. As it has a strong steel truss structure, it reduces corrosion by seawater,
At the same time as increasing durability, a large floating unit is used as a concrete floating block that can be lifted with a general crawler crane etc. to reduce the number of work steps for offshore joining. It is possible to obtain a highly rigid floating structure by strengthening the connection while minimizing the vertical dimension of each concrete floating block as much as possible to float on the water surface. Will be.

[0008] The steel truss is preferably constructed using a steel truss unit that is grounded to the size of one or more concrete floating blocks. Also, by manufacturing concrete floating blocks and framing the steel truss units on land near the sea area where the floating structure is constructed, connecting the floating units in the sea area where the floating structure is constructed, Long-haul towing work can be eliminated, construction in closed sea areas,
Extensions will be easy.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for constructing a floating structure according to the present invention will be described below with reference to the drawings. In FIG. 1, A
Is a block manufacturing yard provided on land, for example, an offshore artificial island or a seaside landfill, and near the sea area where the floating structure 1 is to be constructed. B is a first floating unit adjacent to the block manufacturing yard A. The assembly yard C is a second floating unit assembly yard for connecting a plurality of floating units to assemble a large floating unit, and is provided adjacent to the first floating unit assembly yard.

In the block manufacturing yard A, as shown in FIG. 2, the work of setting the outer formwork 2, arranging the bottom slab concrete crack preventing reinforcing bar 3, setting the inner formwork 4, placing concrete, and the like are performed. The intermediate concrete floating block 5A and the concrete floating block 5B for the outer periphery as shown in FIG. 3 are manufactured. Reference numeral 6 denotes a partition wall for reinforcement provided at an appropriate pitch (for example, 4 m pitch).
Is a hole formed in the partition wall 6 for the purpose of weight reduction and passage of workers, and 8 is a reinforcing rib. The concrete floating block 5B for the outer periphery is a double wall of the outer wall 9a and the inner wall 9b, and is partitioned by the partition wall 10.

The concrete floating blocks 5A, 5
B has a box shape with an open upper surface, and has a weight that can be safely suspended from the block manufacturing yard A to the sea using the crawler crane a arranged in the first floating unit assembly yard B. (For example, about 150 to 160 tons per block).

A concrete floating block 5B for the outer periphery
As shown in FIG. 6, in the state where the construction of the floating structure 1 is completed, the vertical dimension of the outer wall 9a is set to be larger than the sea surface by an appropriate distance (for example, about 1 m). Intermediate concrete floating block 5A
In the state where the construction of the floating structure 1 is completed, since there is no problem even if it is located below the sea surface, the vertical dimension is as small as possible within a range necessary for floating on the sea surface in the middle of construction (for example, , About 3 m). In addition, since the concrete floating block 5B for the outer periphery receives the water pressure from the side in the state where the construction of the floating structure 1 is completed, it is set to be thicker than the side wall of the intermediate concrete floating block 5A.

The concrete floating blocks 5A, 5
It is desirable that the production of B be performed on a work carriage and the work carriage be sequentially moved to the floating unit assembly yard B side in accordance with the production process. For the production of the concrete floating blocks 5A and 5B, a high-strength CFRC (carbon fiber reinforced concrete in which carbon fiber is dispersed in concrete so that a necessary tensile strength can be secured without embedding a main reinforcing bar is used. ), Mixing silica fume particles (to densify concrete by filling silica fume particles smaller than cement particles between cement particles), and adding a glycol ether derivative (cement particles and silica fume). (Reducing the voids of the hydrated structure generated between the particles) eliminates problems such as corrosion of the reinforcing bar, and is a concrete floating block 5A, 5 with high strength, high durability and high water tightness.
It is desirable in manufacturing B.

In the first floating unit assembly yard B, the concrete floating blocks 5A and 5B are lifted one by one by the crawler crane a and floated on the sea surface. In this state, as shown in FIG. Steel frame truss 1 that connects floating blocks made of steel and bridges over the upper surface of the connected group of floating blocks made of concrete
Floating unit 1 with high rigidity
Build 2. That is, the concrete floating block 5
When the vertical dimensions of the side walls to be joined of A and 5B are set as small as possible within the range required for floating on the sea surface during construction, the connection of the joints is made only by the concrete floating blocks 5A and 5B alone. Although the strength (rigidity) may be insufficient, by integrating with the steel truss 11 constructed on the upper part, necessary rigidity is secured, and the floating unit 12 having high rigidity can be constructed. 13 shown in FIG.
An anchor bolt for connecting the steel truss 11.

The steel truss 11 may be constructed by suspending a material steel frame 11a on the upper surface of a concrete floating block, and may be constructed at that position. In the illustrated example, the steel truss 11 is disposed in the first floating unit assembly yard B. Using a crawler crane b, the steel truss unit 11b is grounded, hung on the upper surface of the concrete floating block by the crawler crane b, connected to the concrete floating block, and The steel truss units 11b are connected to each other. In order to reduce offshore work, it is preferable that the steel truss unit 11b is laid to a size equal to or larger than one concrete floating block,
desirable.

In the example shown in FIG. 4, as shown in FIG. 4, the top opening of each concrete floating block 5A, 5B is closed, and a top-end concrete 14 serving as the first floor is cast at sea. Thereafter, the steel truss unit 11b is suspended and connected. When the top concrete 14 is cast, it is desirable to use the half PC plate 14a as a bottom formwork in order to reduce formwork work.

The floating unit 12 manufactured through the above steps is towed one by one by the tug boat 15 to the second floating unit assembling yard C adjacent to the first floating unit assembling yard B, and the floating unit assembling yard. In C,
The plurality of floating units 12 are connected.

Thereafter, the group of the connected floating units 12 (large floating units) is towed by the tugboat 15 to the construction sea area of the floating structure near the second floating unit assembly yard C, and at that position, By connecting with each other, a large-scale floating structure 1 as shown in FIGS. 5 and 6 is constructed. 1A in the figure is a roof slab constructed on the steel truss 11, and is used as a work floor for peripheral start-up work and floating unit connection work.

In the illustrated example, the plurality of floating units 12 are connected to each other in the second floating unit assembly yard C and then towed to the sea area where the floating structure is constructed. The floating units 12 may be towed one by one directly from the yard B to the construction sea area of the floating structure, and may be connected in the construction sea area of the floating structure.

The connection between the concrete floating blocks is performed, for example, by tightening the upper and lower two positions with bolts and nuts 16, and the water stopping at the joint is performed by the water stopping rubber 1 at the upper and lower two positions.
7a, 17b, and upper and lower waterproof rubbers 17a, 17b.
This is achieved by filling non-shrinkable concrete 18 between 17b. In this way, in addition to the double waterproof measures by the waterproof rubbers 17a and 17b, the waterproof measures by the concrete 18 filled in the middle and the waterproof measures by the top concrete 14 are performed. Become
Water entry from the joint can be reliably prevented.

The concrete floating blocks 5A, 5A
Of the bolt insertion holes 19a, 19b formed in the side wall of B, the lower bolt insertion hole 19b may be formed at a position higher than the draft when the concrete floating blocks 5A, 5B are floated on the sea surface. Even when formed at a position lower than the draft, for example, a waterproof rubber 17b is stuck to each of the opposing joint surfaces of the concrete floating block so as to close the bolt insertion holes 19b, and the concrete floating body is formed. Construction is possible by piercing the waterproof rubber 17b from inside the block and inserting a bolt.

According to the above configuration, at least a portion of the floating unit 12 that comes into contact with seawater is formed by connecting a plurality of concrete floating blocks 5A and 5B, and an upper portion that does not come into contact with seawater. However, since the steel truss structure 11 is lightweight and strong, corrosion by seawater is reduced, durability is improved, and at the same time, the concrete floating blocks 5A, 5B are lifted by general crawler cranes a, b. A large floating unit 12 can be constructed by using a lightweight unit so that the number of steps for offshore joining can be reduced, and the vertical dimensions of the individual concrete floating blocks 5A and 5B can be reduced. The rigidity of the floating structure 1 can be obtained by making the connection as strong as possible while minimizing the size required for floating on the water surface. It made.

The concrete floating block 5A,
5B production and the structure of the steel truss unit 11b,
A long distance towing operation is performed at the block manufacturing yard A and the floating unit assembly yard B provided on land near the sea area where the floating structure is constructed, and the final connection of the floating units 12 is performed at the sea area where the floating structure is constructed. Can be eliminated, and construction and expansion in a closed sea area can be easily performed.

[0024]

As described above, according to the present invention,
Since the part that comes in contact with seawater is composed of a concrete floating block and the upper part that does not come in contact with seawater is made of a steel truss structure, corrosion by seawater can be reduced,
Thus, a floating structure having high durability, strong connection of joints, and high rigidity can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan view illustrating a method for constructing a floating structure according to the present invention.

FIG. 2 is a schematic perspective view illustrating a method for manufacturing a concrete floating block.

FIG. 3 is a perspective view showing a part of the concrete floating block in a cutaway manner.

FIG. 4 is an explanatory diagram of a method of constructing a floating unit.

FIG. 5 is a partial schematic perspective view of a floating structure.

FIG. 6 is a sectional view of a main part of the floating structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Floating structure, 5A, 5B ... Concrete floating block, 11 ... Steel truss, 11b ... Steel truss unit, 12 ... Floating unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hisao Mukai 4-1-1-13 Honcho, Chuo-ku, Osaka-shi Inside Takenaka Corporation Osaka Main Store (72) Inventor Shinichi Arioka 4-1-1, Honcho, Chuo-ku, Osaka-shi 13 Inside Takenaka Corporation Osaka Main Store (72) Inventor Makoto Hayashi 4-1-1, Honmachi, Chuo-ku, Osaka City Inside Takenaka Corporation Osaka Main Store (72) Inventor Hiroshi Takiguchi Hiroshima, Chuo-ku, Osaka City 4-1-1-13 Takenaka Corporation Osaka Main Store (72) Inventor Michio Takahashi 4-1-1-13 Honcho Chuo-ku Osaka City Osaka Main Store (72) Inventor Naoshi Matsuoka Osaka 4-1-1-13 Honcho, Chuo-ku, Osaka City Takenaka Corporation Osaka Main Store

Claims (3)

[Claims] 1. A concrete floating block is manufactured on land, the concrete floating blocks are connected to each other while the concrete floating blocks are floating on the sea surface, and the concrete floating blocks are connected to the upper surface of the connected concrete floating blocks. By unifying with the steel frame truss
A method for constructing a floating structure, comprising constructing a floating structure having a high rigidity, connecting the floating units while floating the floating unit on the sea surface. 2. The method of constructing a floating structure according to claim 1, wherein the steel truss is constructed using the trussed steel truss unit. 3. The production of a concrete floating block and the construction of a steel truss unit are performed on land near the sea area where the floating structure is constructed, and the connection of the floating units is performed in the sea area where the floating structure is constructed. The method for constructing a floating structure according to claim 2, wherein: