JPS6227529Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a device for protecting structures erected in the sea, such as bridge piers, from ships.

Bridge piers and other marine structures built in inland seas where there is significant ship navigation need to be protected both during and after construction to ensure the safety of not only the structures but also the ships. This invention was made with the aim of providing a device that satisfies the above requirements. An arcuate or annular body is formed at the upper end of each of these piles at the water surface position and at a position below the water surface, respectively, and is fixed or rotatably attached along the outer circumferential surface of the pile, and Teflon, etc. is attached to the outer circumference of the pile. consisting of a sliding member or pulley equipped with a rope guide groove, and several wire ropes suspended around all of the piles via each of these sliding members or pulleys so as to be able to freely slide in the horizontal direction in an encircling manner. The gist of the invention is an anti-shock device for offshore structures. The following description will be made based on an embodiment shown in the drawings.

That is, in FIGS. 1 and 2, A indicates a protected object, that is, a marine structure, and the device according to this invention is installed surrounding the structure A.
The structure consists of a plurality of piles 1 erected at regular intervals around the structure A, and fixed sliding members 3 or 3 installed at the upper ends of the piles 1 above and below the water surface, respectively. It consists of several wire ropes 2 which are hung around and parallel to all of the piles via rotatable pulleys 6, and are slidably slidable in the horizontal direction on each pile 1.

Assuming that a ship collided with the wire rope 2 surrounding the pile 1 erected as described above,
At the same time as the collision occurs, tension acts on the wire rope 2, and this tension causes a force F to act on the pile 1. The relationship between this force F and the displacement δ at the wire rope installation point of pile 1 is expressed as
Think like the diagram. That is, in the same figure, F _p
is the force that generates a total plastic bending moment in the cross section of the pile 1 at the point where the maximum bending moment of the pile 1 occurs, and δ _p is the displacement at that time. Furthermore, the energy absorbed by the pile 1 when the displacement of the pile 1 reaches δ _a is shown by the area of the shaded part in the figure. In other words, the absorbed energy per pile is E = F _p (δ _a -1/2δ _p ) Since ship collision energy is absorbed by the deformation of several piles, ΣE = E _v E _v : Ship's It becomes collision energy. Note that the above displacement δ is allowed until the pile 1 buckles.

Since only the deformation of the pile 1 increases without the force due to the tension of the wire rope 2 exceeding F _p , the tension of the wire rope 2 does not exceed the tension that generates F _p , so the diameter of the wire rope 2 is not made much. It doesn't need to be thick.

It is a good idea to absorb the energy of the collision with as many piles 1 as possible, and for this purpose, the sliding mechanism that minimizes the friction between the piles 1 and the wire rope 2 is used to transmit the tension of the wire rope 2 to the entire pile. Consideration must be given to the construction, and FIGS. 3 to 6 show examples thereof.

That is, in the case shown in FIGS. 3 and 4, a sliding material 3 such as Teflon is pasted on the part of the pile 1 that the wire rope 2 comes into contact with, and a material 4 for preventing the wire rope from coming off is attached.
is attached. In another embodiment shown in FIGS. 5 and 6, a pulley 6 is mounted on a support 5 attached to a pile 1, and a wire rope 2 is hung on the pulley 6. Note that if the outer circumferential surface of the sliding member 3 has a rope guide groove like the outer circumferential surface of the pulley 6, the wire rope slip-off preventing member 4
can be omitted.

According to this idea, it consists of multiple piles driven around structures such as bridge piers, and parallel wire ropes that surround the piles and are stretched so as to be able to slide around the piles. Most of the energy of the collision is absorbed by the deformation of the pile, and when the pile reaches the plastic region, the force applied to the pile hardly increases, so the tension in the wire rope does not increase very much.
Ships rarely break down. It should be noted that the deformation of piles can be taken into account up to the plastic range, but if the deformation reaches a point where it cannot be restored, it is sufficient to replace it each time, and it is highly effective as a shock absorbing device that not only protects offshore structures but also prevents damage to ships. Moreover, it has the advantage that it can be provided at a relatively low price.

[Brief explanation of the drawing]

Fig. 1 is a front view showing one embodiment of this invention, Fig. 2 is a plan view, Fig. 3 is a side view showing an example of the wire rope sliding means, Fig. 4 is a plan view thereof, and Fig. 5 is another example. FIG. 6 is a plan view thereof, and FIG. 7 is an explanatory view of the action at the time of a collision. 1 is a stake, 2 is a wire rope.

Claims (1)

[Scope of utility model registration request] A plurality of piles are erected at regular intervals around an offshore structure, and each of these piles is fixed or rotatable at the upper end of the water surface and below the water surface, respectively, along the outer circumferential surface of the pile. A sliding member or a pulley formed into an arc-shaped or annular body and having a rope guide groove made of Teflon or the like on its outer circumferential surface, and a surrounding shape surrounding all the piles through each of these sliding members or pulleys. An anti-shock device for marine structures consisting of several wire ropes that are hung so as to be able to slide horizontally.