JP2708072B2 - Floating bridge pier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater pier foundation.

[0002]

2. Description of the Related Art A pier foundation in the sea is a caisson installation method in which a caisson is installed on the seabed, a multi-column foundation method in which a number of piles are constructed, and a steel pipe sheet pile is used to close the foundation. There is known a steel pipe well cylinder method.

[0003]

However, when the water depth becomes large, the foundation becomes long and the construction becomes extremely difficult.

Further, there is a tension leg system as a structure at a large depth of water. However, the conventional tension leg system can control the vertical movement but cannot control the horizontal or torsional movement. This technology cannot be used as a pier foundation as it is.

Accordingly, an object of the present invention is to provide a pier foundation fixed by a tension rig which can cope with a large depth of water.

[0006]

According to the present invention, an anchor is settled on the bottom of a water, and the anchor and the pier foundation of the floating body are connected to each other by diagonal tension legs in which at least three or more are combined. The pier foundation and the anchor are connected at the upper and lower portions of the pier foundation of the floating body by the combination tension legs, respectively, and at least one of the upper and lower portions is connected by the combination tension rig of three or more points, and The pier foundation is fixed.

[0007]

[Explanation of operation and effect] In the floating pier constructed as described above, the floating body which is the pier foundation is connected to at least three or more diagonal tension rigs with respect to the anchor anchored on the seabed. At least one of the upper and lower portions of the floating body is fixed by three or more combination tension rigs.

Accordingly, if the pretension of the tension rig is adjusted to a predetermined value by adjusting the buoyancy of the floating body and the length of the tension rig, the tension rig is mounted diagonally, so that not only in the vertical direction but also in the horizontal direction. The horizontal direction and the torsional direction are fixed by the component force.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a floating-sink type anchor 7 is attached to a seabed G, and a floating body base indicated by reference numeral 1 is connected to the anchor 7 by tension rigs 4 and 5. The floating foundation 1 is composed of an upper part 2 and a lower part 3, and an upper end 3 a of the lower part 3 is provided with a pier main tower 6 and is configured to protrude above the sea surface W.

Referring also to FIG. 2, the anchor 7 and the upper part 2 of the floating body are three or more of four points (in the illustrated example, three and four).
a, 4b, 4b).

The lower end 3b of the lower part 3 of the floating foundation is connected to an anchor 7 by a tension leg 5 to prevent the floating foundation 1 from inclining.

Hereinafter, the installation of the floating foundation will be described.

First, the anchor 7 is manufactured by the dock 10 (see FIG. 3), and the floating foundation 1 is manufactured on the anchor 7 via the horse 11 (see FIG. 4). Tension rig 4,5
Is attached and launched (see FIG. 5), towed to the site, the floating body foundation 1 and the anchor 7 are connected by the suspension wire 12, and the water is gradually poured into the anchor 7 to descend (see FIG. 6).

When the tension rig has worked, the anchor 7 is lowered and landed while pouring water onto the anchor 7 and the floating foundation 1, and the buoyancy is adjusted to adjust the pre-tension of the tension rig (see FIG. 7). Ends.

Therefore, referring to FIG. 8, when buoyancy F is applied, tension T is applied to the tension leg. Assuming that the horizontal component force is x, when a horizontal force x1 is applied in a direction opposite to the x, the horizontal direction is stable unless the force x1 is larger than x. If there are three or more such fixed points, the surface including the fixed points becomes stable.

Therefore, the floating base 1 fixed by the tension leg as in the embodiment is fixed vertically, horizontally and torsionally, and can be used as a foundation of a pier.

[0017]

Since the present invention is constructed as described above, a floating foundation can be provided as a pier foundation, and can be easily constructed even at a large water depth as compared with the prior art. Therefore, the construction period can be shortened.

[Brief description of the drawings]

FIG. 1 is a side view showing the configuration of a floating foundation showing one embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a side view illustrating a step (1) of constructing FIG. 1;

FIG. 4 is a side view illustrating a step (2) of constructing FIG. 1;

FIG. 5 is a side view illustrating a step (3) of constructing FIG. 1;

FIG. 6 is a side view illustrating a step (4) of constructing FIG. 1;

FIG. 7 is a side view illustrating a final step (5) of constructing FIG. 1;

FIG. 8 is a diagram showing a balance of forces applied to a tension leg.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Floating body base part 2 ... Upper part 3 ... Lower part 4, 5 ... Tension leg 6 ... Pier main tower 7 ... Anchor

Claims (1)

(57) [Claims] An anchor is attached to the water floor, and the anchor and the pier foundation of the floating body are connected by an oblique tension leg in which at least three or more are combined, and the pier foundation of the floating body and the anchor are connected to the pier foundation of the floating body. The upper and lower parts are connected by the above-mentioned combination tension legs, and at least one of the upper and lower parts is connected by three or more combination tension rigs to fix the pier foundation of the floating body. Floating pier.