Wall

Abstract

To provide a wall body or the like easy to construct.SOLUTION: A dike 2 is a concrete cylindrical wall body provided on a PC tank 1. Prestress is introduced into the dike 2 by circumferential tendons 11, 15 and a vertical tendon 13 of the dike 2. The vertical tendon 13 is arranged only on a bottom of the dike 2. At a top 21 of the dike 2, the tendon 15 in the circumferential direction of the dike 2 is arranged so as to be inclined with respect to a horizontal direction. The tendon 15 is arranged in a sine curve shape.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wall of a tank or the like. [Background technology]

[0002] 2. Description of the Related Art Prestressed concrete (PC) tanks are facilities for storing liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas) (see, for example, Patent Document 1).

[0003] Figure 6 shows an example of a PC tank 100. The PC tank 100 has a cylindrical liquid retaining dike 200 on a base slab 5 supported by piles 4 in the ground, and an inner tank 6 and an outer tank 3 made of steel plates or the like installed inside the dike. The inner tank 6 is provided for storing liquid.

[0004] The liquid retaining dike 200 is a cylindrical concrete wall, usually cylindrical, that is installed to prevent liquid from leaking to the outside in case of damage to the inner tank 6. The liquid retaining dike 200 needs to be constructed to be able to withstand the liquid pressure in the event of damage to the inner tank 6, and therefore prestress is introduced by tensioning the circumferential and vertical tension members.

[0005] Figure 7 is an example of a vertical cross section of the dike 200. The above-mentioned liquid pressure can be resisted by introducing prestress into the dike 2 through circumferential tension members 11, but the dike 2 is not normally subjected to liquid pressure from inside the tank. For this reason, a bending moment in the vertical plane is applied to the dike 2 due to the circumferential prestress. The vertical tension members 13 are provided mainly to provide reinforcement against this bending moment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-219140 A Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, taking into consideration that the above-mentioned bending moment will be large at the top and bottom of the dike, vertical tension members are provided only at the top and bottom of the dike. However, at the top of the dike, a large number of vertical tension members are placed in addition to the circumferential tension members of the dike, which raises concerns that construction will become more complicated due to an increase in the number of tensions.

[0008] The present invention has been made in consideration of the above problems, and has an object to provide a wall or the like that is easy to construct. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present invention provides a cylindrical wall made of concrete, characterized in that prestress is introduced by circumferential and vertical tension members of the wall, the vertical tension members are arranged only at the bottom of the wall, and at the top of the wall, the circumferential tension members of the wall are arranged so as to be inclined with respect to the horizontal direction.

[0010] In this invention, by inclining the circumferential tendons of the wall at the top of a cylindrical wall such as a flood barrier with respect to the horizontal, it is possible to introduce prestress in both the circumferential and vertical directions of the wall with a single tendon. This makes it possible to introduce the necessary prestress into the wall with a small number of tendons, which makes construction easier by reducing the number of times tensioning is required.

[0011] It is desirable for the angled portion of the tendon at the top of the wall to have a curve. This allows both ends of the tendon to be smoothly connected when both ends are arranged horizontally from the standpoint of ease of tensioning work, etc.

[0012] The tendons at the top of the wall are preferably arranged in a wavy pattern in the circumferential direction of the wall, and are preferably arranged in a sine curve pattern in the circumferential direction of the wall. This allows prestress to be introduced over a long range in the circumferential direction of the wall. Also, by making the tendons sine-curve shaped, the curvature of the tendons does not become too large, making the installation of the tendons easier.

[0013] It is desirable that a notch or a projection for fixing the end of the tendon at the top of the wall is provided on the outer surface of the wall. This allows tensioning work to be carried out from outside the wall, making construction easier.

[0014] It is desirable that a plurality of the tendons are provided on the inside and outside of the top of the wall body. This makes it possible to introduce a large prestress by the tendons and to make the prestress introduced by the tendons uniform in the circumferential direction of the wall body. Effect of the Invention

[0015] According to the present invention, walls and the like that are easy to construct can be provided. [Brief description of the drawings]

[0016] [Figure 1] A diagram showing PC tank 1. [Diagram 2] A diagram showing the liquid barrier 2. [Diagram 3] FIG. 2 is a diagram showing the arrangement of tendons 15. [Figure 4] FIG. 2 is a diagram showing the arrangement of tendons 15. [Diagram 5] FIG. 2 is a diagram showing the arrangement of tendons 15. [Figure 6] A diagram showing a PC tank 100. [Figure 7] A diagram showing a liquid retaining wall 200. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0018] (1.Dike 2) FIG. 1 is a diagram showing a PC (prestressed concrete) tank 1 having a liquid retaining dike 2 according to an embodiment of the present invention.

[0019] The liquid barrier 2 is a tubular wall, and in this embodiment is cylindrical. The liquid barrier 2 is formed by arranging concrete precast blocks 10 (hereinafter sometimes referred to as "blocks") in the circumferential direction of the liquid barrier 2 and stacking them vertically. Joints 7 made of a filler material such as concrete are provided between adjacent blocks 10 in the circumferential and vertical directions of the liquid barrier 2. The configuration of the PC tank 1 other than the liquid barrier 2 is the same as that described in Figure 6.

[0020] 2(a) is a diagram showing a vertical cross section of the dike 2. Tendons 11, 13, and 15 are embedded in the dike 2. The tendons 11, 13, and 15 are passed through, for example, a sheath (not shown) in the block 10. As the tendons 11, 13, and 15, PC steel materials such as PC steel bars and PC steel wires can be used.

[0021] The tension member 11 is a tension member in the circumferential direction of the dike 2 and is provided in a portion of the dike 2 excluding the top portion 21 .

[0022] The tendons 13 are vertical tendons and are provided only at the bottom of the dike 2.

[0023] The tension member 15 is a circumferential tension member of the dike 2 provided at the top 21 of the dike 2, and is arranged so as to be inclined with respect to the horizontal direction. The tension member 15 is provided over the entire circumferential length of the dike 2. Note that in addition to the top 21 of the dike 2, it is also possible to provide the tension member 15 at the middle part of the dike 2 in the height direction.

[0024] Figure 3(a) is a view showing the top 21 of the liquid barrier 2 expanded in the circumferential direction. The circumferential direction of the liquid barrier 2 corresponds to the left-right direction in Figure 3(a), and Figure 3(a) shows a part (1 / 3 of the circumference) of the liquid barrier 2 in the circumferential direction.

[0025] In this embodiment, the tendons 15 are arranged in a wavy pattern around the circumferential direction of the floodwall 2, and when viewed in a specific direction (for example, from left to right in Figure 3(a)), they have a sloping portion that slopes from top to bottom and an inclined portion that slopes from bottom to top.

[0026] In particular, in this embodiment, this inclined portion has a curve, and when both ends of the tensioning material 15 are arranged horizontally from the standpoint of ease of tensioning work, which will be described later, the both ends can be smoothly connected.

[0027] The waveform of the tendon 15 is a sine curve, and the tendon 15 continues smoothly (without corners). Two tendons 15 are placed one on top of the other, inside and outside the dike 2, which allows the prestress introduced into the dike 2 to be increased.

[0028] Notches 16 are provided on the outer surface of the top 21 of the dike 2 for fixing the ends of these tendons 15. The tendons 15 have their ends tensioned and are fixed by fixing bodies 17 arranged in the notches 16. The notches 16 are provided at a position corresponding to the apex of a sine curve where the orientation of the tendons 15 is horizontal, thereby allowing the ends of the tendons 15 to be tensioned horizontally and fixed, making the tensioning work easier. Note that instead of the notches 16, protrusions protruding outward from the dike 2 may be provided to fix the ends of the tendons 15.

[0029] In this embodiment, as shown in Fig. 3(b), the components Px and Py of the prestress force (compressive force) P due to tensioning of the tendons 15 can simultaneously introduce circumferential prestress and vertical prestress into the dike 2. As a result, vertical tendons are no longer necessary and the number of times tensioning is reduced, making the construction of the dike 2 easier.

[0030] The tendons 15 are arranged in a sheath (not shown) embedded in the block 10, and the block 10 is manufactured in such a way that a sheath having a shape that matches the arrangement of the tendons 15 is embedded therein.

[0031] In this embodiment, the dividing positions of the blocks 10 in the circumferential direction of the liquid barrier 2 are regularly determined in accordance with the waveform of the tendon 15, so that the top 21 of the liquid barrier 2 can be formed by blocks 10 with a common sheath arrangement, thereby reducing the labor required for manufacturing the blocks 10. For example, in the example of Figure 3(a), the dividing positions of the blocks 10 are determined so as to divide the length of one period of the waveform of the tendon 15 into six, so that the sheath arrangement is common to multiple blocks 10 as exemplified by symbol A.

[0032] As described above, in this embodiment, by inclining the circumferential tension members 15 of the dike 2 with respect to the horizontal direction at the top 21 of the dike 2, prestress in the circumferential and vertical directions of the dike 2 can be introduced by a single tension member 15. As a result, the required prestress can be introduced to the dike 2 with a small number of tension members 15, which makes construction easier by reducing the number of times tensioning is required.

[0033] In addition, in this embodiment, the inclined portion of the tension member 15 has a curve, and when both ends of the tension member 15 are arranged horizontally from the standpoint of ease of tensioning work, etc., the both ends can be smoothly connected.

[0034] Furthermore, in this embodiment, by arranging the tendons 15 in a wave-like manner, prestress can be introduced over a long range in the circumferential direction of the dike 2. In particular, in this embodiment, the tendons 15 are arranged in a sine curve shape, so that the curvature of the tendons 15 does not become too large, making it easier to install the tendons 15.

[0035] In this embodiment, the tendons 15 are provided in two piles, one on the inside and one on the outside, so that a large prestress can be introduced by the tendons 15. However, only one tendon 15 may be provided without piles on the inside and the outside.

[0036] Furthermore, the outer surface of the dike 2 is provided with notches 16 or protrusions for fixing the ends of the tendons 15, which makes construction easier as tensioning work can be carried out from outside the dike 2. The ends of the tendons 15 can also be fixed to the pilasters 22 (see Figure 1) of the dike 2.

[0037] However, the present invention is not limited to the above embodiment. For example, in this embodiment, the length of one tendon 15 is set to be equal to or longer than one period of the waveform of the tendon 15, but as shown in Fig. 4(a), multiple tendons 15 may be arranged in the circumferential direction of the dike 2 so as to be continuously wavy, and the length of one tendon 15 may be set to be shorter than one period of the waveform.

[0038] In this example, as shown in Figure 4(b), the length of one tension member 15 is set to half the length of the waveform, and the ends of adjacent tension members 15 circumferentially around the floodwall 2 are arranged so as to overlap each other.

[0039] In this embodiment, as shown in Fig. 3(a), two tension members 15 with the same corrugation, one inside and one outside, are arranged shifted in the circumferential direction of the liquid barrier 2 by a length equivalent to half the period of the corrugation, but the number of tension members 15 overlapped on the inside and outside of the liquid barrier 2 is not limited to this, and may be three or more. The amount of shift of the tension members 15 is also not limited to the above.

[0040] For example, in the example of Figure 5(a), three inner and outer tendons 15 of the same corrugation are arranged with a shift of 1 / 3 period of the corrugation in the circumferential direction of the dike 2. By appropriately staggering the arrangement of the tendons 15 by less than half a period in this way, the magnitude of the circumferential prestress and the vertical prestress of the dike 2 can be made uniform in the circumferential direction of the dike 2, and vertical prestress can be introduced at any position in the circumferential direction of the dike 2.

[0041] In this embodiment, the waveform of the tendons 15 is a sine curve, but the waveform of the tendons 15 is not limited to this, and may be arranged in a triangular wave, for example. As shown in Fig. 5(b), multiple tendons 15 can be arranged at intervals in the circumferential direction of the dike 2, and multiple tendons 15 with the same inclination can be arranged in the circumferential direction of the dike 2. In the example of Fig. 5(b), one tendon 15 is arranged across multiple blocks 10, but one tendon 15 may be arranged obliquely within one block 10. Although the inclined portion of the tendons 15 is linear, it may be curved.

[0042] In this embodiment, the flood barrier 2 is constructed using precast blocks 10, but the present invention can also be applied when the flood barrier 2 is constructed using cast-in-place concrete, and the concrete can be poured with a sheath for passing the tension member 15 in place.

[0043] In addition, this embodiment is explained by giving an example of the arrangement of the tension members 15 of the dike 2 of the PC tank 1, which makes it easy to construct the PC tank 1, but the present invention is not limited to this and can be applied to various types of cylindrical wall bodies.

[0044] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the above examples. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the technical ideas disclosed in this application, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0045] 1, 100: PC tank 2, 200: Liquid dike 10: Precast blocks 11, 13, 15: Tensile material 16: Notch 17: Fixing body 21:Top

Claims

1. A cylindrical wall made of concrete, Prestressing is introduced by circumferential and longitudinal tendons in the wall; the longitudinal tendons are disposed only at the bottom of the wall; A wall body, characterized in that at the top of the wall body, a circumferential tension member of the wall body is arranged so as to be inclined with respect to the horizontal direction.

2. 2. The wall of claim 1, wherein the angled portion of the tendon at the top of the wall has a curve.

3. 3. The wall according to claim 2, wherein the tendons at the top of the wall are arranged in a wavy pattern around the circumferential direction of the wall.

4. 4. The wall according to claim 3, wherein the tendons at the top of the wall are arranged in a sine curve shape in the circumferential direction of the wall.

5. 5. A wall body according to claim 1, wherein a notch or a protrusion for fixing an end of the tendon at the top of the wall body is provided on an outer surface of the wall body.

6. 6. The wall structure according to claim 1, wherein a plurality of the tendons are provided on the inside and outside of the top of the wall structure.

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