JP6474999B2 - Bridge pier - Google Patents

Description

The present invention relates to rolling down hard to the pier.

Conventionally, an existing pier whose foundation is a “direct foundation” or an existing pier that is a “pile foundation having a structure in which the pile and the foundation are not connected” is known. Since such existing piers are directly provided on the ground (including ground reinforced with wooden piles, etc.), they may fall over due to an earthquake or the like.
As a fall-suppressing construction method that makes it difficult for such existing piers to fall, for example, a construction method in which the ground and the pier are integrated with a ground anchor (for example, see Patent Document 1), or a construction method that increases the contact area between the ground and the pier. And so on.

JP-A-9-209373

However, in the case of the construction method in which the ground and the pier are integrated with the ground anchor, the anchor is large and the ground anchor fixing portion of the pier needs to be reinforced, which increases the cost.
In the case of a construction method that increases the contact area between the ground and the pier, when the pier is installed in a river or sea, it must be shielded to install a member that increases the contact area. For this reason, a large-scale facility is required, resulting in problems such as increased costs and a longer construction period. In addition, water leakage may occur and it may not be possible to construct safely.

The present invention has been made in view of the above circumstances, it is to provide a rolling defeat hard piers.

In order to solve the above problems, the pier of the present invention is:
A pier directly on the ground,
The pier body,
A resistance means capable of generating a resistance force in a direction that cancels the moment when an external force that generates a moment to tilt the pier body acts on the pier body; and
The resistance means includes
An arm attached to the pier body;
A cord-like material hanging from the tip of the arm;
A weight attached to the lower end of the cord-like material,
Tip of said arm away from the ground, it becomes a state where the cord-like material is stretched from the slack depending from the distal end, it is configured to generate the resistance force.

Therefore, when an external force that generates a moment to tilt the pier body acts on the pier body, it is possible to generate a resistance force in a direction that cancels the moment. Can be provided.
In addition , it is possible to effectively suppress the overturn with a simple configuration.

Alternatively, the pier of the present invention is
A pier directly on the ground,
The pier body,
A resistance means capable of generating a resistance force in a direction that cancels the moment when an external force that generates a moment to tilt the pier body acts on the pier body; and
The resistance means includes
An arm attached to the pier body and having a hole formed along the substantially vertical direction at the tip;
A rod-like material that slidably penetrates the hole,
A weight attached to the lower end of the rod-shaped material,
The rod-shaped material is provided with a stopper at the upper end in order to prevent the rod-shaped material from falling off from the arm,
When the tip of the arm moves away from the ground and the stopper of the rod-shaped material penetrating the hole formed in the tip is brought into contact with the arm from the separated state, the resistance force It is comprised so that it may produce.

Therefore, when an external force that generates a moment to tilt the pier body acts on the pier body, it is possible to generate a resistance force in a direction that cancels the moment. Can be provided.
In addition , it is possible to effectively suppress the overturn with a simple configuration.

Alternatively, the pier of the present invention is
A pier directly on the ground,
The pier body,
A resistance means capable of generating a resistance force in a direction that cancels the moment when an external force that generates a moment to tilt the pier body acts on the pier body; and
The resistance means includes
An arm attached to the pier body;
A loose fitting material having an opening;
A weight attached to the lower end of the loose fitting material,
The tip of the arm is loosely fitted in the opening,
Away tip of said arm from said ground, said tip by a state in which the edge and the arms of the opening is in contact from the separated state to loosely fitted, is configured to cause said resistance It is .

Therefore, when an external force that generates a moment to tilt the pier body acts on the pier body, it is possible to generate a resistance force in a direction that cancels the moment. Can be provided.
In addition , it is possible to effectively suppress the overturn with a simple configuration.

Preferably,
A plurality of the arms are attached to the pier body,
The plurality of arms may be configured to extend radially when the pier body is viewed from above.

  By comprising in this way, a fall can be suppressed irrespective of the shaking direction of the ground.

Preferably,
The weight has a container that can store water, and can be configured to function as a weight when water is stored in the container.

  By comprising in this way, especially when the pier main body is installed in water, a weight can be prepared and installed more easily.

According to the present invention, it is possible to provide a rolling defeat hard piers.

It is a figure which shows an example of a structure of the existing pier. It is a figure which shows an example of the fall control method of this embodiment, and an example of a structure of the bridge pier (fall-resistant bridge pier) of this embodiment. It is a figure which shows the example of the attachment method of an arm, and the attachment position of an arm. It is a figure which shows the modification 1 of this embodiment. It is a figure which shows the modification 2 of this embodiment. It is a figure which shows the modification of a weight.

  With reference to the drawings, embodiments of the overturning suppression method and the pier according to the present invention will be described. The embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

First, the existing pier 10 will be described.
FIG. 1 is a diagram illustrating an example of the configuration of an existing pier 10.
The existing pier 10 is a rail pier made of unreinforced concrete. As shown in FIG. 1, as shown in FIG. 1, a floor slab 1, which has a quadrangular pillar shape and can be laid with a track, is installed via a bridge girder 2. .
Hereinafter, the extending direction of the bridge girder 2 is referred to as the front-rear direction, and the horizontal direction orthogonal to the extending direction of the bridge girder 2 is referred to as the left-right direction.

  The existing pier 10 is directly provided on the ground (including ground reinforced by wooden piles and the like). That is, the foundation of the existing pier 10 is a “direct foundation” or a “pile foundation having a configuration in which the pile and the foundation are not connected”. Therefore, the existing pier 10 may be tilted due to the inertial force of the earthquake and may fall down in some cases during an earthquake. Therefore, in the present embodiment, in order to change the existing pier 10 to the fall-resistant pier 20 that is harder to fall than the existing pier 10, for example, as shown in FIG. A resistance means R capable of generating a resistance force in a direction to cancel the moment when an external force (such as an inertial force of an earthquake) that generates a moment acts on the existing pier 10 is attached to the existing pier 10. And

  For example, as shown in FIG. 2A, the resistance means R is attached to the arm 21 attached to the existing pier 10, the rope 22 that hangs down from the tip of the arm 21, and the lower end of the rope 22. And a weight 23. As the cord-like material 22, for example, a member (rope, chain, or the like) that can transmit a tensile force made of a known material such as steel or fiber-reinforced plastic can be used.

For example, as shown in FIG. 2C, when an external force that generates a moment to tilt the existing pier 10 acts on the existing pier 10 and the existing pier 10 tilts, the fulcrum of the existing pier 10 falls. The tip of the arm 21 on the O side (right side in the example shown in FIG. 2C) approaches the ground, and the tip of the arm 21 on the side opposite to the overturning fulcrum O (left side in the example shown in FIG. 2C). Move away from the ground.
The length of the cord-like material 22 is increased when the tip of the arm 21 where the cord-like material 22 hangs away from the ground and the distance between the tip of the arm 21 and the ground reaches a predetermined length. It is set to the length that will be in the state.
Therefore, when the distance between the tip of the arm 21 and the ground is less than a predetermined length, the cord-like material 22 hanging from the tip of the arm 21 is in a slack state, but the tip of the arm 21 When the distance from the ground is equal to or longer than a predetermined length, the cord-like material 22 that hangs down from the tip of the arm 21 is stretched.

  When the arm 21 and the weight 23 are connected via the slackened cord-like material 22, the load of the weight 23 is not transmitted to the arm 21. Therefore, as shown in FIG. 2B, for example, when the external force that generates a moment to tilt the existing pier 10 is not acting on the existing pier 10, the left cable-like material 22 is also Since the right cord 22 is also in a slack state, neither the left arm 21 nor the right arm 21 is loaded with the weight 23.

  On the other hand, when the arm 21 and the weight 23 are connected via the stretched cord-like material 22, the load of the weight 23 is transmitted to the arm 21. Therefore, for example, as shown in FIG. 2 (c), an external force that generates a moment to tilt the existing pier 10 acts on the existing pier 10 so that the existing pier 10 tilts and the left arm 21 When the distance between the tip and the ground reaches a predetermined length, the right rope 22 remains slack but the left rope 22 is stretched, so the right arm The load of the weight 23 is not applied to 21, but the load of the weight 23 is applied to the left arm 21. As a result, a moment M in a direction opposite to the moment for tilting the existing pier 10 is generated, and a resistance force for canceling the moment for tilting the existing pier 10 is generated. Therefore, the existing pier 10 to which the resistance means R is attached (that is, the anti-falling pier 20) is the state before the resistance means R is attached when the ground is shaken in the direction in which the lateral component is larger than the longitudinal component. It becomes harder to fall than the existing pier 10

In the present embodiment, for example, as shown in FIG. 3A, the left arm 21 is fixed to the left side surface of the existing pier 10 using a post-construction anchor or the like (not shown), and the existing pier 10 Although the right arm 21 is fixed to the right side surface, the mounting method of the arm 21 can be appropriately changed. FIG. 3 is a view showing a state where the overturn-resistant pier 20 is viewed from above.
Specifically, for example, as shown in FIG. 3B, a rod-shaped member A that penetrates the existing pier 10 in the left-right direction is fixed to the existing pier 10, and the left side surface of the existing pier 10 among the rod-shaped members A is fixed. It is also possible to make the portion protruding more than the left arm 21 function and the portion protruding from the right side surface of the existing bridge pier 10 to function as the right arm 21.
For example, as shown in FIG. 3C, each of the existing pier 10 includes a first rod-shaped member A1 along the front side surface of the existing pier 10 and a second rod-shaped member A2 along the rear side surface of the existing pier 10. Is fixed using post-installed anchors (not shown), and the portion of the first rod member A1 and the second rod member A2 that protrudes from the left side surface of the existing pier 10 functions as the left arm 21. Of the first rod-like member A1 and the second rod-like member A2, a portion protruding from the right side surface of the existing pier 10 can be configured to function as the right arm 21.

Moreover, the arm 21 is not limited to what protrudes from the left side surface and the right side surface of the existing bridge pier 10, and the mounting position of the arm 21 can be arbitrarily changed as appropriate.
For example, the arm 21 may protrude from the front side surface and the rear side surface of the existing pier 10. In this case, the existing pier 10 to which the resistance means R is attached (that is, the anti-falling pier 20) is installed before the resistance means R is attached when the ground shakes in a direction in which the front-rear direction component is larger than the left-right direction component. It becomes harder to fall than the existing pier 10.
Moreover, the arm 21 may protrude from the left side surface, the right side surface, the front side surface, and the rear side surface of the existing pier 10 as shown in FIGS. 3 (d) and 3 (e), for example. Like the tip-resistant pier 20 shown in FIG. 3D, a plurality of arms 21 extend radially when the existing pier 10 is viewed from above, or the tip-resistant pier 20 shown in FIG. When the plurality of arms 21 extend in all directions when the existing pier 10 is viewed from above, the existing pier 10 to which the resistance means R is attached (that is, the fall-resistant pier 20) is swayed in the ground. Regardless of the direction, it is more difficult to fall than the existing pier 10 before the resistance means R is attached.

  The mounting method of the arm 21, the mounting position of the arm 21, the number of mounting the arms 21, the length of the cord-like material 22, etc. are the size of the existing pier 10, the shape of the installation location of the existing pier 10, and the installation of the existing pier 10. It can be set as appropriate according to the seismic performance required at the place.

  Next, an example of the procedure of the overturning suppression method that makes it difficult for the existing pier 10 directly provided on the ground to fall, that is, the procedure of the overturning suppression method for changing the existing pier 10 to the anti-falling pier 20 will be described.

First, the arm 21 is attached to the existing pier 10.
Next, a weight 23 is installed below the distal end portion of the arm 21, and the distal end portion of the arm 21 and the weight 23 are connected by a cord-like material 22. In this way, the existing pier 10 can be changed to the fall-resistant pier 20.

  According to the overturning control method of the present embodiment described above, the overturning control method makes it difficult to overturn the existing pier 10 directly provided on the ground, and an external force that generates a moment to tilt the existing pier 10 is generated. The resistance means R capable of generating a resistance force in a direction to cancel the moment when acting on the existing pier 10 is configured to be attached to the existing pier 10.

Therefore, since only the resistance means R is attached to the existing pier 10, inexpensive and safe construction is possible, and the construction period can be shortened.
Specifically, since the resistance means R is simply attached to the existing pier 10, no reinforcement at the time of construction or a small-scale reinforcement is sufficient. Therefore, compared with the conventional fall prevention construction methods, such as the construction method which integrates a ground and a bridge pier with a ground anchor, cheap construction becomes possible.
Moreover, since the resistance means R is only attached to the existing pier 10, even if the existing pier 10 is installed in a river or the sea, the attachment position of the resistance means R (specifically, the attachment position of the arm 21). You can work on the surface of the water. Therefore, large-scale facilities for water shielding are not necessary, and it is not necessary to consider safety against water leakage, so compared with conventional methods for preventing overturning such as methods that increase the contact area between the ground and the pier. Therefore, inexpensive and safe construction is possible, and the construction period can be shortened.
Furthermore, it is a construction method that increases the contact area between the ground and the pier, and when the pier is a railway pier, in a narrow space near the track, the construction becomes complicated, and a place to install a member that increases the contact area is installed. Although problems such as being unable to ensure occur, the resistance means R is simply attached to the existing pier 10 so that construction that is not affected by the track (track) is possible.

  According to the pier of this embodiment, it is a pier (fall-resistant pier 20) directly provided on the ground, and an external force that generates a moment to tilt the pier body (existing pier 10) and the pier body is generated. And a resistance means R capable of generating a resistance force in a direction to cancel the moment when acting on the pier body.

Therefore, when an external force that generates a moment to incline the pier body acts on the pier body, it is possible to generate a resistance force in a direction to cancel the moment. A tip-resistant pier 20) can be provided.
Note that the pier body is not limited to the existing pier 10 and may be a newly installed pier.

  Moreover, according to the pier of this embodiment, the resistance means R includes the arm 21 attached to the pier body (existing pier 10), the rope 22 that hangs down from the tip of the arm 21, and the rope 22 A weight 23 attached to the lower end, and the distal end portion of the arm 21 moves away from the ground, and the cord-like material 22 that hangs from the distal end portion is brought into a relaxed state, thereby generating resistance. It is possible to make it constitute.

  By comprising in this way, a fall can be effectively suppressed with a simple structure.

  In the above-described embodiment, the configuration and the like illustrated in the accompanying drawings are merely examples, and are not limited thereto, and can be appropriately changed within the scope of the effects of the present invention. . In addition, various modifications can be made without departing from the scope of the object of the present invention.

<Modification 1>
For example, as shown in FIG. 4A, the resistance means R is attached to the existing pier 10 and has an arm 31 having a hole 31a formed in the tip portion along the substantially vertical direction, and the hole 31a is slidable. And a weight 33 attached to the lower end of the rod-shaped material 32, and a weight 33 attached to the lower end of the rod-shaped material 32. As the rod-shaped material 32, for example, a self-supporting member made of a known material such as steel or fiber-reinforced plastic can be used.

The rod-shaped member 32 penetrates the arm 31 and is provided with a stopper 32a at the upper end in order to prevent the rod-shaped member 32 from falling off from the arm 31. Since the rod-shaped member 32 is slidable substantially vertically with respect to the arm 31, when the existing pier 10 is inclined and the tip of the arm 31 through which the rod-shaped member 32 penetrates approaches the ground, the arm 31. When the tip of the arm 31 through which the existing pier 10 is inclined and the bar-like material 32 penetrates away from the ground, it slides substantially downward with respect to the arm 31.
The length of the rod-shaped material 32 (specifically, the distance between the weight 33 and the stopper 32a) is such that the tip of the arm 31 through which the rod-shaped material 32 penetrates is away from the ground, and the tip of the arm 31 and the ground. Is set to a length at which the arm 31 is in contact with the stopper 32a provided at the upper end of the rod-shaped member 32.
Therefore, when the distance between the tip of the arm 31 and the ground is less than the predetermined length, the arm 31 is separated from the stopper 32a of the rod-like material 32 penetrating the arm 31 and the arm 31. When the distance between the distal end portion and the ground is equal to or longer than a predetermined length, the arm 31 is in contact with the stopper 32a of the rod-shaped member 32 penetrating the arm 31.

  When the arm 31 is in a state of being separated from the stopper 32 a of the rod-shaped material 32 that penetrates the arm 31, the load of the weight 33 is not transmitted to the arm 31. Therefore, for example, as shown in FIG. 4B, when an external force that generates a moment to tilt the existing pier 10 is not acting on the existing pier 10, the left bar member 32 is also on the right side. Since the stopper 32a is also separated from the arm 31 in the rod-shaped member 32, the load of the weight 33 is not applied to the left arm 31 or the right arm 31.

  On the other hand, when the arm 31 is in contact with the stopper 32 a of the rod-shaped member 32 that passes through the arm 31, the load of the weight 33 is transmitted to the arm 31. Therefore, for example, as shown in FIG. 4 (c), an external force that generates a moment to tilt the existing pier 10 acts on the existing pier 10 so that the existing pier 10 tilts and the left arm 31 When the distance between the tip and the ground reaches a predetermined length, the right bar 32 remains in the state where the stopper 32a is separated from the arm 31, but the left bar 32 has the stopper 32a connected to the arm 31. Since the right arm 31 is not touched, the load of the weight 33 is not applied to the right arm 31, but the load of the weight 33 is applied to the left arm 31. As a result, a moment M in a direction opposite to the moment for tilting the existing pier 10 is generated, and a resistance force for canceling the moment for tilting the existing pier 10 is generated. Therefore, the existing pier 10 to which the resistance means R is attached (that is, the overturn-resistant pier 30) is less likely to fall than the existing pier 10 before the resistance means R is attached.

  According to the pier of the first modification described above (the fall-resistant pier 30), the resistance means R is attached to the pier body (in the case of this modification, the existing pier 10), and extends substantially vertically along the tip. The arm 31 having the formed hole portion 31a, a rod-shaped material 32 that slidably penetrates the hole portion 31a, and a weight 33 attached to the lower end of the rod-shaped material 32 are provided. In order to prevent the material 32 from falling off from the arm 31, a stopper 32 a is provided at the upper end. It is comprised so that resistance may be produced when it will be in the state which contacted from the state from which 32a and the said arm 31 were spaced apart.

  Therefore, it is possible to effectively suppress the overturn with a simple configuration.

<Modification 2>
For example, as shown in FIG. 5A, the resistance means R includes an arm 41 attached to the existing pier 10, a loose fitting material 42 having an opening 42 a, and a weight attached to the lower end of the loose fitting material 42. 43, and the tip of the arm 41 may be loosely fitted in the opening 42a. As the loose fitting material 42, for example, a self-supporting member made of a known material such as steel or fiber reinforced plastic can be used.

The tip of the arm 41 is loosely fitted in the opening 42a of the loosely fitting material 42, and the tip is movable in the substantially vertical direction within the opening 42a.
The length of the opening 42a in the vertical direction is such that the tip of the arm 41 loosely fitted in the opening 42a moves away from the ground (that is, the tip of the arm 41 is substantially upward in the opening 42a). When the distance between the tip of the arm 41 and the ground reaches a predetermined length, the arm 41 and the edge (specifically, the upper edge) of the opening 42a are in contact with each other. Is set to the length to be.
Therefore, when the distance between the tip of the arm 41 and the ground is less than a predetermined length, the arm 41 and the edge of the opening 42a in which the tip of the arm 41 is loosely fitted are in a separated state. When the distance between the tip of the arm 41 and the ground is a predetermined length or more, the arm 41 and the edge of the opening 42a that loosely fits the tip of the arm 41 are in contact with each other.

  When the arm 41 and the edge of the opening 42 a are separated from each other, the load of the weight 43 is not transmitted to the arm 41. Therefore, for example, as shown in FIG. 5B, when an external force that generates a moment to incline the existing pier 10 is not acting on the existing pier 10, the left arm 41 is also on the right side. Since the arm 41 is also separated from the edge of the opening 42a, neither the left arm 41 nor the right arm 41 is loaded with the weight 43.

  On the other hand, when the arm 41 and the edge of the opening 42 a are in contact with each other, the load of the weight 43 is transmitted to the arm 41. Therefore, for example, as shown in FIG. 5C, an external force that generates a moment to tilt the existing pier 10 acts on the existing pier 10, so that the existing pier 10 tilts and the left arm 41 When the distance between the tip and the ground reaches a predetermined length, the right arm 41 remains separated from the edge of the opening 42a, but the left arm 41 contacts the edge of the opening 42a. As a result, the right arm 41 is not loaded with the weight 43, but the left arm 41 is loaded with the weight 43. As a result, a moment M in a direction opposite to the moment for tilting the existing pier 10 is generated, and a resistance force for canceling the moment for tilting the existing pier 10 is generated. Therefore, the existing pier 10 to which the resistance means R is attached (that is, the overturn-resistant pier 40) is less likely to fall than the existing pier 10 before the resistance means R is attached.

  According to the pier of the second modification described above (the fall-resistant pier 40), the resistance means R includes the arm 41 attached to the pier body (the existing pier 10 in the case of this modification) and the opening 42a. A loose fit material 42 and a weight 43 attached to the lower end of the loose fit material 42, the tip of the arm 41 is loosely fitted in the opening 42 a, and the tip of the arm 41 is kept away from the ground. The arm 41 is configured such that a resistance force is generated when the edge of the opening 42a (the upper edge in the case of this modification) and the arm 41 are in contact with each other from the separated state. ing.

  Therefore, it is possible to effectively suppress the overturn with a simple configuration.

Moreover, in said embodiment and modification, the existing pier 10 is not limited to the product made from an unreinforced concrete, For example, the product made from a reinforced concrete, bricks, stones, etc. may be sufficient.
Further, the existing pier 10 is not limited to a railway pier, and may be another pier.
Further, the shape of the existing pier 10 is not limited, and may be a polygonal column shape, a columnar shape, or a flared shape (such as a polygonal frustum or a truncated cone). Further, the side surface of the existing pier 10 may be uneven. The existing pier 10 may be erected in the vertical direction or may be erected obliquely with respect to the vertical direction.

In the embodiment and the modification described above, for example, metal weights are used as the weights 23, 33, and 43, but the weights are not limited thereto.
For example, as shown in FIG. 6, when the existing pier 10 is installed in water (river, sea, etc.), a weight 53 may be used instead of the weight 23. The weight 53 has a container 53a capable of storing water, and functions as a weight when water (river water, seawater, etc.) is stored in the container 53a. By comprising in this way, a weight can be prepared and installed more easily. Of course, the weight 53 can be applied to both the fall-resistant pier 30 of the first modification and the fall-resistant pier 40 of the second modification.

10 Existing pier (Body pier body)
20 Fall-resistant bridge pier (pier)
21 Arm 22 Cord-like material 23 Weight 30 Fall-resistant bridge pier (pier)
31 Arm 31a Hole 32 Bar-shaped material 32a Stopper 33 Weight 40 Fall-resistant bridge pier (bridge pier)
41 Arm 42 Floating material 42a Opening 43 Weight 53 Weight 53a Device R Resistance means

Claims (5)

A pier directly on the ground,
The pier body,
A resistance means capable of generating a resistance force in a direction that cancels the moment when an external force that generates a moment to tilt the pier body acts on the pier body; and
The resistance means includes
An arm attached to the pier body;
A cord-like material hanging from the tip of the arm;
A weight attached to the lower end of the cord-like material,
The distal end of the arm moves away from the ground, it becomes a state where the cord-like material is stretched from the slack depending from the distal end, the bridge leg said to cause the resistance. A pier directly on the ground,
The pier body,
A resistance means capable of generating a resistance force in a direction that cancels the moment when an external force that generates a moment to tilt the pier body acts on the pier body; and
The resistance means includes
An arm attached to the pier body and having a hole formed along the substantially vertical direction at the tip;
A rod-like material that slidably penetrates the hole,
A weight attached to the lower end of the rod-shaped material,
The rod-shaped material is provided with a stopper at the upper end in order to prevent the rod-shaped material from falling off from the arm,
When the tip of the arm moves away from the ground and the stopper of the rod-shaped material penetrating the hole formed in the tip is brought into contact with the arm from the separated state, the resistance force bridge leg you, characterized in that cause. A pier directly on the ground,
The pier body,
A resistance means capable of generating a resistance force in a direction that cancels the moment when an external force that generates a moment to tilt the pier body acts on the pier body; and
The resistance means includes
An arm attached to the pier body;
A loose fitting material having an opening;
A weight attached to the lower end of the loose fitting material,
The tip of the arm is loosely fitted in the opening,
The tip of the arm moves away from the ground, and the edge of the opening that loosely fits the tip is brought into contact with the arm from a separated state, thereby generating the resistance force. bridge leg you. A plurality of the arms are attached to the pier body,
The pier according to any one of claims 1 to 3 , wherein the plurality of arms extend radially when the pier body is viewed from above. The weight has a water capable of accommodating vessels, to any one of claims 1 to 4, characterized in that functions as a weight by water is contained within the said device The listed pier.

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