Wall body construction method and tank

Abstract

To provide a tank wall body construction method and the like that can suitably construct a tank wall body.SOLUTION: A dike is a tank wall body having a cylindrical main body 20 and a hunch 21 provided outside a bottom of the main body 20. Prestress is introduced into the dike by a tension member 22 in a circumferential direction. The main body 20 of the dike is formed by stacking precast concrete blocks 200 vertically. The hunch 21 is formed by pouring concrete outside the bottom of the main body 20 after the main body 20 is formed to at least a height of the hunch 21.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for constructing a wall and a tank. [Background technology]

[0002] Patent Documents 1 and 2 disclose a prestressed concrete tank (hereinafter referred to as a PC tank) that has a liquid retaining wall on its outer periphery. The liquid retaining wall is a cylindrical wall within which circumferential tendons are embedded. The tendons are arranged in multiple stages at intervals along the height of the liquid retaining wall, and these tendons introduce circumferential prestress into the liquid retaining wall, reinforcing the liquid retaining wall so that it can withstand the liquid pressure inside the liquid retaining wall.

[0003] When circumferential prestress is applied to the dike, a bending moment occurs in the vertical plane at the bottom of the dike that tends to bend the dike inward toward the tank. To reinforce against this bending moment, Patent Document 1 applies prestress to the dike using vertical tension members, and thickens the bottom of the dike outward to form a haunch, ensuring the necessary structural cross-section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4793640 [Patent Document 2] Japanese Patent Application Publication No. 2023-19735 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the bottom of the dike, including the haunch, is formed from cast-in-place concrete, which requires time for construction, including the installation of formwork. Inner and outer tanks made of metal plates or other materials are installed inside the dike, but this construction requires mechanical work, and for construction reasons, this work cannot begin until the dike has been constructed to a certain height. Therefore, if the bottom of the dike, including the haunch, is formed from cast-in-place concrete, there is a risk that the start of mechanical work will be delayed, leading to delays in the construction process.

[0006] On the other hand, Patent Document 2 describes constructing a flood barrier by stacking precast blocks one above the other, which allows the construction of a flood barrier in a relatively short time. Patent Document 2 also discloses that the bottom of a flood barrier with a haunch is made of a precast block. However, the precast block has a different shape from the precast blocks in the other parts, and the size and weight are increased by the amount of the haunch, making it inconvenient in terms of manufacturing and transportation.

[0007] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a wall construction method and the like that can suitably construct the wall of a tank. [Means for solving the problem]

[0008] A first invention for solving the above-mentioned problems is a method for constructing a wall of a tank, the wall having a cylindrical main body and a haunch provided on the outside of the bottom of the main body, prestress is introduced by circumferential tendons, the main body is formed by stacking concrete precast blocks one above the other, and the haunch is formed by forming the main body at least to the height of the haunch and then pouring concrete outside the bottom of the main body.

[0009] In this invention, by using precast blocks to form the main body of the wall, the height required to begin mechanical work on the inner and outer tanks can be secured early, which shortens the construction period. On the other hand, by forming the haunches using cast-in-place concrete, the size and weight of the precast blocks at the bottom of the wall can be prevented from increasing, which is preferable in terms of manufacturing and transporting the precast blocks. As described above, this invention allows for the optimal construction of tank walls.

[0010] Preferably, at the bottom of the wall, the circumferential tendons are embedded in the haunches, and above the bottom of the wall, the circumferential tendons are embedded in the body. This allows circumferential prestress to be introduced into the entire wall including the haunches.

[0011] The wall is preferably constructed on a base mat, and the haunches are connected to the main body and the base mat using connecting bars embedded in the haunches. This allows the corbels to be securely integrated into the main body of the wall and the base slab.

[0012] The second invention is a tank having a wall body, the wall body having a cylindrical body formed by stacking concrete precast blocks one above the other, and a haunch formed of cast-in-place concrete on the outside of the bottom of the body, and characterized in that prestress is introduced into the wall body by circumferential tension members. A second invention is a tank having a wall constructed by the construction method of the first invention. [Effects of the Invention]

[0013] The present invention can provide a wall construction method and the like that can suitably construct the wall of a tank. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 shows a tank 10. [Figure 2]A diagram showing the liquid barrier 2. [Figure 3] FIG. 2 is a diagram illustrating a method for constructing a flood barrier 2. [Figure 4] FIG. 10 shows a connecting bar 24a. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0016] (1. Tank 10 and dike 2) Figure 1 is a diagram showing a tank 10 according to an embodiment of the present invention. The tank 10 is an above-ground tank that stores liquids such as LNG (Liquefied Natural Gas) and ammonia, and is a PC tank in which a liquid retaining wall 2 made of concrete precast blocks 200 (hereinafter sometimes referred to as "blocks") is provided on a base mat 1, and prestress is introduced into the liquid retaining wall 2. The base mat 1 is a plate-shaped member made of concrete.

[0017] The liquid barrier 2 is a wall having a cylindrical body 20. An inner tank and an outer tank made of metal plates or the like are installed inside the liquid barrier 2. The liquid barrier 2 is installed to prevent liquid from leaking to the outside in the event that the inner tank or outer tank is damaged. In the figure, the reference numeral 3 denotes a steel roof installed on top of the inner tank and outer tank. Note that "inside" refers to the center side in the plane of the tank 10, and the opposite side, i.e., the outside side of the tank 10, is referred to as "outside."

[0018] The plane of the dike 2 is circular according to the diameter of the tank 10, but the inner periphery may be a regular polygon such as a regular 48-gon or regular 80-gon. The main body 20 of the dike 2 is formed by arranging blocks 200 left and right around the periphery of the dike 2 and stacking them in upper and lower layers, and providing joints 4 between adjacent blocks 200 in the vertical and horizontal directions. The joints 4 can be formed by filling the gaps between the blocks 200 with a filler material. The filler material is a cement-based solidification material such as mortar, but is not limited to this.

[0019] In this embodiment, a haunch 21 is provided on the outside of the bottom of the main body 20 of the dike 2. The haunch 21 is an increased thickness portion that increases the thickness of the main body 20 of the dike 2 on the outside. The haunch 21 is formed from cast-in-place concrete.

[0020] Fig. 2 is a diagram showing a vertical cross section along the thickness direction of the dike 2. As shown in Fig. 2, the haunch 21 is a cross-sectional portion of a roughly right-angled triangle that widens outward relative to the main body 20 of the dike 2, and is provided on the outside of the block 200 that constitutes the main body 20.

[0021] The outer surface of the haunch 21 has an inclined portion 211 that slopes linearly downward and outward relative to the vertical direction, a horizontal portion 212 that continues from the upper end of the inclined portion 211 toward the main body 20 of the dike 2, and a vertical portion 213 that continues from the lower end of the inclined portion 211 toward the base slab 1. It is also possible to omit the horizontal portion 212 and the vertical portion 213 and have the outer surface of the haunch 21 consist only of the inclined portion 211.

[0022] Inside the dike 2, tendons 22 are provided in the circumferential direction of the tank 10, and tendons 23 are provided in the vertical direction. PC steel materials such as PC steel wires are used for the tendons 22 and 23. The tendons 22 and 23 are arranged through a sheath (not shown) inside the dike 2.

[0023] A plurality of circumferential tendons 22 are provided at intervals above and below. At the bottom of the dike 2, the circumferential tendons 22 are embedded in the haunch 21 rather than in the main body 20. The tendons 22 in the haunch 21 are arranged at intervals along the inclined portion 211 on the outer surface of the haunch 21. Above the bottom of the dike 2, the tendons 22 are embedded in the main body 20 of the dike 2.

[0024] The vertical tendons 23 are arranged in the height direction of the dike 2, inside the circumferential tendons 22. The vertical tendons 23 are arranged from the top of the dike 2 to the base slab 1, and the portion above the base slab 1 is arranged within the main body 20 of the dike 2. For structural reasons, short vertical tendons may be arranged within the dike 2 in addition to the above tendons 23. These tendons are arranged from the top surface of the block 200 midway along the height direction of the main body 20 to the base slab 1, and the portion above the base slab 1 is arranged within the main body 20 of the dike 2.

[0025] Also provided within the haunch 21 are connecting bars 24 for connecting the main body 20 of the dike 2 and the base slab 1 to the haunch 21. The connecting bars 24 are shaped to fit the outer surface of the haunch 21, and are arranged along the outer surface of the haunch 21, outside the circumferential tendons 22.

[0026] That is, the connecting reinforcement 24 has an inclined portion 241 that slopes linearly with respect to the vertical direction so that it slopes outward as it goes downward, a horizontal portion 242 that continues from the upper end of the inclined portion 241 toward the main body 20 of the flood barrier 2, and a vertical portion 243 that continues from the lower end of the inclined portion 241 toward the base slab 1, and the inclined portion 241, horizontal portion 242, and vertical portion 243 are buried at positions corresponding to the inclined portion 211, horizontal portion 212, and vertical portion 213 on the outer surface of the haunch 21, respectively.

[0027] The horizontal portion 242 of the connecting bar 24 protrudes from the haunch 21 toward the main body 20, and this protruding portion is inserted into the outer end of a tubular connector 201 provided on the outer surface of the block 200 of the main body 20. The end of the anchoring bar 202 has been inserted into the inner end of the connector 201 in advance, and the haunch 21 is connected to the main body 20 of the dike 2 by the connecting bar 24, for example, by filling the connector 201 with a filler material (not shown).

[0028] The same applies to the connection between the haunch 21 and the base slab 1. That is, the vertical portion 243 of the connecting bar 24 protrudes from the haunch 21 toward the base slab 1, and this protruding portion is inserted into the upper end of a tubular connector 101 provided on the top surface of the base slab 1. The end of the anchoring bar 102 is inserted beforehand into the lower end of the connector 101, and the haunch 21 is connected to the base slab 1 by the connecting bar 24 by filling the connector 101 with a filler (not shown). The anchoring bars 102, 202 on the base slab 1 or block 200 side can also be omitted. It is also possible to place the connector 101 inside the haunch 21, have the anchoring bar 102 protrude upward from the base slab 1, and connect the protruding portion to the vertical portion 243 of the connecting bar 24 using the connector 101 inside the haunch 21.

[0029] Furthermore, by forming the haunch 21 from cast-in-place concrete, the upper and lower multiple tiers of blocks 200 that make up the main body 20 of the dike 2 can basically be made the same shape, including the block 200 at the bottom of the main body 20 (except for the top block 200 in the example of Figure 2), and these blocks 200 can be efficiently manufactured using the same formwork. The bottom block 200 of the main body 20 is roughened on the surface facing the haunch 21 during manufacturing, and the unevenness of the roughening improves the adhesion of the concrete to the haunch 21.

[0030] (2. Construction method of flood barrier 2) In this embodiment, the upper block 200 is lowered by a crane or the like and placed on top of the lower block 200, and the process of forming a joint 4 between the upper and lower blocks 200 is repeated to form the main body 20 of the liquid barrier 2 to a predetermined height halfway along the height of the liquid barrier 2, as shown in Figure 3(a).

[0031] This predetermined height is sufficient for construction purposes to start mechanical work on the inner tank and outer tank inside the dike 2, and may be, for example, about 10 m, depending on the case. In this embodiment, mechanical work on the inner tank, etc. begins after the main body 20 of the dike 2 is formed to the predetermined height.

[0032] On the other hand, with regard to the dike 2, as shown in Figure 3(b), the formation of the main body 20 by stacking the blocks 200 proceeds, and the haunch 21 is formed on the outside of the bottom of the main body 20 of the dike 2. The haunch 21 is formed by arranging the connecting bars 24 and the circumferential tendons 22 in the haunch 21 as described above, and then installing a formwork (not shown) and pouring concrete.

[0033] After this, the blocks 200 are stacked to complete the main body 20 of the dike 2 up to the top, and prestress is introduced into the dike 2 by tensioning the tendons 22 and 23, thereby constructing the dike 2 shown in Figure 2. In parallel with this, the inner and outer tanks and their steel roofs 3 are completed inside the dike 2, thereby constructing the tank 10 shown in Figure 1.

[0034] As explained above, in this embodiment, by using the blocks 200 to form the main body 20 of the dike 2, the height required to start mechanical work on the inner and outer tanks of the tank 10 can be secured early, and starting the mechanical work early leads to a shorter construction period. On the other hand, by forming the haunch 21 from cast-in-place concrete, the size and weight of the blocks 200 at the bottom of the dike 2 can be prevented from increasing, which is preferable in terms of manufacturing and transporting the blocks 200. As described above, in this embodiment, the dike 2 for the tank 10 can be constructed in an optimal manner.

[0035] In this embodiment, circumferential tendons 22 are embedded in the haunches 21, allowing circumferential prestress to be introduced to the entire dike 2, including the haunches 21. Furthermore, the haunches 21 can be securely integrated with the main body 20 of the dike 2 and the foundation slab 1 by means of connecting reinforcement 24.

[0036] However, the present invention is not limited to the above-described embodiment. For example, while the cross section of the haunch 21 in this embodiment is a substantially right-angled triangle, the cross section of the haunch 21 is not limited to this and may be a square, rectangle, or other rectangular shape. The arrangement and shape of the connecting bars 24 within the haunch 21 are also not limited to those described above, as long as they can connect and integrate the haunch 21 with the main body 20 of the dike 2 and the foundation slab 1. For example, as shown in Figure 4, insert bars 24a embedded between the block 200 of the main body 20 and the concrete of the haunch 21 may be used to connect the main body 20 and the haunch 21. The same applies to the connection between the foundation slab 1 and the haunch 21.

[0037] In addition, in this embodiment, the main body 20 of the liquid barrier 2 is formed to a predetermined height, and the haunch 21 is formed after mechanical work on the inner tank etc. has begun inside the liquid barrier 2; however, the formation of the haunch 21 can basically be carried out at any time after the main body 20 of the liquid barrier 2 has been formed to the height of the haunch 21.

[0038] For example, the haunch 21 can be formed before the main body 20 of the dike 2 is formed to the predetermined height. The stacking of the blocks 200 of the main body 20 can be carried out independently of the construction of the haunch 21, so the formation of the haunch 21 does not delay the formation of the main body 20 of the dike 2, which in turn does not delay the start of mechanical work.

[0039] Alternatively, the haunch 21 may be formed after the main body 20 of the dike 2 is formed all the way to the top. For example, the main body 20 of the dike 2 may be formed all the way to the top with an opening (not shown) at the bottom through which workers and equipment involved in mechanical work on the inner tank, etc., can pass. In this case, after the main body 20 is formed all the way to the top, prestress can be introduced above the opening by tensioning the circumferential tendons 22, and then the opening can be closed with concrete or the like and the haunch 21 can be formed, and prestress can be introduced by tensioning the circumferential tendons 22 in the height range of the opening, including the haunch 21.

[0040] Furthermore, the quantity and arrangement of the tendons 22, 23 are determined by the design and are not limited to those described in Figure 2 and other figures. For example, in this embodiment, the circumferential tendons 22 are embedded in the haunches 21 rather than in the main body 20 at the bottom of the dike 2. However, the circumferential tendons 22 may be embedded in the main body 20 at the bottom of the dike 2 without being embedded in the haunches 21. In this case, it is also possible to form the haunches 21 after introducing prestress through tension in the circumferential tendons 22 over the entire height of the dike 2. Furthermore, in the example of Figure 2, the lower parts of the longitudinal tendons 23 are linearly inclined with respect to the vertical direction so as to slope outward as they extend downward, but the entire length of the longitudinal tendons 23 may be arranged along the vertical direction.

[0041] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications or alterations within the scope of the technical ideas disclosed herein, and it is understood that these modifications also fall within the technical scope of the present invention. [Explanation of symbols]

[0042] 1: Basic version 2: Liquid dike 10: Tank 20: Main body (of the dike) 21: Hunch 22, 23: Tensile material 24, 24a: connective muscles 200: Precast blocks

Claims

1. 1. A method for constructing a wall of a tank, comprising the steps of: The wall body has a cylindrical main body and a haunch provided on the outside of the bottom of the main body, and prestress is introduced by a circumferential tension member, The body is formed by stacking precast concrete blocks one above the other; A method for constructing a wall, characterized in that the haunch is formed by forming the body at least to the height of the haunch and then pouring concrete outside the bottom of the body.

2. At the bottom of the wall, the circumferential tendons are embedded in the haunches; 2. The method of claim 1, wherein the circumferential tendons are embedded in the body above the bottom of the wall.

3. The wall is constructed on a foundation mat; 2. The method for constructing a wall according to claim 1, wherein the haunches are connected to the main body and the base slab using connecting bars embedded in the haunches.

4. A tank having a wall, The wall body is A cylindrical body formed by stacking precast concrete blocks one above the other, a haunch formed of cast-in-place concrete on the outside of the bottom of the body; and A tank characterized in that prestress is introduced into the wall body by circumferential tendons.

Images