JPH05278677A - Large-scale floating body structure - Google Patents

Abstract

PURPOSE:To reduce external force due to wave without producing increase in corrosion preventing cost for a floating body structure by providing a wave dissipating panel, extended to below the structure and sunk under water, on the periphery of the floating body structure integrally with each other, in a large-scale floating body structure such as floating body airport, floating body artificial island, etc. CONSTITUTION:A floating body structure 1 is constructed with a steel floating unit 3 comprising an upper plate 3a, side plates 3b, and a lower surface plate 3c. Its necessary rigidity is secured by framework ribs, etc., and a space for obtaining a necessary buoyancy is formed. In this case, wave dissipating panels 2 for preventing wave from invading are provided on the external periphery of the floating body structure 1. On these wave dissipating panels 2, curved wave reflectors 2a are provided at their top, and their lower ends are extended to a specified depth of D where wave pressure distribution 4 due to wave is reduced and formed integral with the floating body structure 1 by means of supporting member 2b. The wave dissipating panel 2 is steel surface panel, concrete surface panel, slit panel, inclined panel, etc. Thus a surface area in splash zone can be reduced, and corrosion preventing cost can also be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-scale floating structure such as a floating airport and a floating artificial island.

[0002]

2. Description of the Related Art In recent years, when planning airport facilities, waste treatment facilities, energy facilities, etc., it is difficult to secure a vast land on land, and there are many oppositions due to the destruction of the natural environment.
There is a tendency to use the sea space for reasons such as noise pollution and other pollution problems. In addition to these facilities, there are plans for marine leisure facilities and artificial islands such as maritime cities. Since these facilities have been deployed offshore from the critical area, there are many plans to construct them in deep water. Conventionally, these facilities were mainly constructed by a landfill method, but as the water depth increased, a huge amount of landfill soil was required, which required enormous construction funds along with the construction of a large revetment, and the construction period was long. There are many problems such as concern about water pollution of the surrounding sea area during construction, which takes a long time, and ground subsidence after completion. Therefore, a floating structure type artificial island has been proposed as a solution to the problems of the landfill method. As shown in Fig. 3, the artificial island of the floating structure type that has been conventionally proposed is one in which the inside of a box-shaped floating structure made of steel plate or concrete slab is floated by buoyancy or as shown in Fig. 4. In some cases, a large number of floating columns 7 are provided below the deck 6 so that the deck 6 is located above the sea surface.

[0003]

The former of the conventionally proposed floating structure is a large-scale structure in which the floating structure 1 exceeds the wavelength of the wave, as shown in FIG. A large wave pressure acts on the lower surface of the floating structure as a lifting force P at each wavelength interval of the waves, so that when the bending rigidity of the floating structure 1 is weak, a deformation as shown by a dotted line 8 in FIG. 3 occurs. Therefore,
In order to reduce the deformation due to this wave external force, the bending rigidity must be increased, and the strength of the floating structure 1 must be increased, which is uneconomical.

In the latter case, in order to reduce the wave external force acting on the floating structure 1, only the floating column 7 provided below the deck 6 receives the wave external force as shown in FIG. It can be said that it is diverted from a proven one for ships. Since this structure type reduces the wave external force, the floating body strength can be made lower than the former. However,
The floating column 7 contributes only to the buoyancy and does not contribute to the overall rigidity. Moreover, in the case of this structure, the anticorrosion cost is very expensive. That is, assuming long-term maintenance-free, the splash zones on the side and bottom surfaces of the deck 6 are heavily anticorrosive, and the splash zone of the most severe corrosive environment near the water surface of the floating column 7 is more expensive anticorrosion method such as metal lining. Need to be adopted. It should be noted that the upper surface of the deck 6 can be protected against corrosion by submersing the concrete lining in water.

The present invention is intended to solve the above problems of the conventional floating structure, and to reduce the wave external force acting on the lower surface of the floating structure and to increase the corrosion protection cost of the floating structure. There is no need to provide an economical large-scale floating structure.

[0006]

In order to achieve the above-mentioned object, the present invention extends to the outer circumference of a floating structure and extends below the lower surface of the floating structure so as to be submerged to the lower surface of the floating structure. It is composed of a large-scale floating structure characterized in that a wave-dissipating plate that reduces the transmission of wave external force is provided integrally with the floating structure.

[0007]

The large-scale floating structure of the present invention is provided with a wave-dissipating plate which is submerged to the outer periphery of the floating structure in such a manner that the acting force of the waves decreases in the wave pressure distribution of the waves. This is to reduce the transmission of wave external force to the lower surface, and to make only the substantially uniform buoyancy act on the lower surface of the floating structure so that the rigidity of the floating structure can be reduced.

[0008]

Embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an embodiment of the present invention. FIG. 1 is a sectional view of a floating structure, and FIG. 2 is a schematic view of an entire floating structure. The floating structure 1 of this embodiment is constructed by welding and joining a large number of floating units 3 made of steel, and a wave-dissipating plate 2 for preventing waves from entering the lower surface of the floating body is provided on the outer circumference. Each floating body unit 3 is composed of an upper plate 3a, a side plate 3b, and a lower plate 3c, and the inside thereof has a space for securing necessary rigidity and a necessary buoyancy by a frame rib (not shown). . The wave-dissipating plate 2 is provided with a curved wave return 2a at the upper end, and is extended at the lower end to a required depth where the wave pressure distribution 4 due to waves is reduced.
It is provided integrally with. If the lower end depth D of the wave-dissipating plate 2 is too deep, the pressure receiving area of the tidal current becomes large and the mooring equipment becomes large, so the wave pressure in the wave pressure distribution 4 becomes 1/3 to 1/10 of the maximum value. It is desirable to reduce the depth.
As the wave-eliminating plate 2, a steel plate or concrete face plate, slit plate, inclined plate or the like is adopted. The floating structure 1 according to the present embodiment is protected from corrosion by maintenance-free corrosion with the upper surface 3a covered with concrete, and from the vicinity of the water surface of the outer cylinder to heavy corrosion with an epoxy resin or a lining with titanium metal.
Corrosion protection such as concrete lining is performed, and the lower surface 3c and the submerged part of the outer cylinder wave-dissipating plate part are galvanically protected.

[0009]

According to the present invention, the wave-dissipating plate provided on the outer periphery of the floating structure reduces the external force of the waves acting on the lower surface of the floating structure, thereby making it possible to reduce the rigidity of the floating structure. The surface area of the splash zone of the floating structure is smaller than that of the conventional method, and the corrosion protection cost can be reduced, so that higher economic efficiency can be achieved as compared with the conventional floating structure. For example, 700 ha (1,400 m x 5,000
m) When the present invention is applied to a floating structure of a scale, the economic effect is 60% compared with the conventional floating column method.
%, Anticorrosion cost was reduced to about 20%, and the total calculation cost was reduced to about 1/2.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross-sectional view of an example of a floating structure of the present invention.

FIG. 2 is a diagram showing an overall view of an example of a floating structure of the present invention.

FIG. 3 is a diagram illustrating an example of a conventional floating structure.

FIG. 4 is a diagram illustrating an example of another conventional floating body structure.

[Explanation of symbols]

 1 Floating structure 2 Wave-dissipating plate 3 Floating unit 4 Wave pressure distribution

Claims (1)

[Claims] 1. A wave-dissipating plate which extends below the lower surface of the floating structure and is submerged in the outer periphery of the floating structure to reduce the transmission of wave external force to the lower surface of the floating structure, is integrated with the floating structure. A large-scale floating structure characterized by being installed in.