JP6753061B2 - PC tank and how to build it - Google Patents

Description

The present invention relates to a PC tank and a method for constructing the same, and particularly to a PC tank suitable for a PCLNG tank for storing liquefied natural gas and a method for constructing the same.

In recent years, when storing liquefied natural gas (hereinafter referred to as LNG), it is arranged in and around a metal double-shell LNG tank consisting of an outer tank and an inner tank from the viewpoint of effective use of the site and increase in capacity. A PCLNG tank (hereinafter simply referred to as a PC tank), which is a facility that ensures liquidtightness by integrating the liquid barrier with the liquid barrier and making the liquid barrier made of PC (prestressed concrete), is adopted. ..

The PC-made liquid barrier (hereinafter referred to as PC liquid barrier) is along the circumferential direction with respect to the concrete cylindrical peripheral wall erected on the outer peripheral edge of the foundation slab on which the LNG tank is placed. It is composed of reinforced concrete in which the PC steel material inserted through the steel material and the PC steel material arranged along the vertical direction and arranged in a linear or U-shaped bent shape at the lower end are arranged. Then, these PC steel materials in the circumferential direction and the vertical direction are tensioned and fixed, so that prestress in the circumferential direction and the vertical direction is introduced into the cylindrical peripheral wall, so that cracks in the PC liquid barrier are prevented and storage is performed. Even if the LNG inside leaks from the inner tank, the liquidtightness is ensured so that it can be kept in the facility.

Here, the PC liquid barrier is rigidly joined to the foundation plate on the lower end side and the roof on the upper end (top) side in order to improve the resistance during an earthquake. In this state, the PC liquid barrier is connected in the circumferential direction. When the tension force of is introduced, the deformation is restrained by the foundation slab and the roof near the lower end and the upper end of these PC liquid barriers, and a bending moment is generated along the vertical direction. Since cracks occur, it is necessary to introduce not only the tension force in the circumferential direction described above but also the tension force in the vertical direction.

Japanese Patent No. 5516963

Therefore, conventionally, as described in Patent Document 1, by arranging the PC steel materials in the vertical direction collectively on the lower end portion and the upper end portion of the PC liquid barrier, the lower end portion and the upper end portion of these PC liquid barriers are conventionally arranged. A PC tank has been developed that effectively prevents the occurrence of cracks in the above.

However, in the PC tank of Patent Document 1, although the arrangement of the PC steel material in the vertical direction in the intermediate portion other than the upper end portion and the lower end portion of the PC liquid barrier can be abolished, the introduction of unnecessary prestress can be omitted. Since the PC steel materials are aggregated and arranged at the upper end and the lower end of the PC liquid barriers other than the above, there is a problem that the installation work of the PC steel materials becomes complicated and the material cost increases. ..

The present invention has been made in view of the above-mentioned circumstances, and by using a material that is cheaper than the PC steel material, bending along the vertical direction in the PC liquid barrier while achieving low cost and facilitation of construction. The purpose is to make it possible to effectively prevent the occurrence of cracks due to moments.

In order to achieve the above object, the method for constructing a PC tank according to the present invention is
Construction to construct a PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate. It's a method
A cylindrical peripheral wall is erected along the outer circumference of the foundation plate,
A formwork is placed at a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion with a gap from the outer periphery, and fiber reinforced concrete or fiber reinforced mortar is placed in the gap to reinforce the outer circumference. A portion is provided integrally with the cylindrical peripheral wall via a fixing member provided in advance on the cylindrical peripheral wall.
It is characterized in that prestress is introduced into the cylindrical peripheral wall by tensioning the PC steel material in the circumferential direction inserted through the cylindrical peripheral wall to form the PC liquid barrier.

Further, the method for constructing the PC tank according to the present invention is as follows.
Construction to construct a PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate. It's a method
When the cylindrical peripheral wall is erected along the outer periphery of the foundation slab, the cylindrical peripheral wall is previously provided only on the upper end portion, the lower end portion, or the upper end portion and the lower end portion of the outer peripheral surface of the cylindrical peripheral wall. A reinforcing portion made of fiber reinforced concrete or fiber reinforced mortar formed in a panel shape with the fixing member arranged toward the surface is placed as a part of the formwork, and concrete is cast to form the cylindrical peripheral wall. Stand up,
It is characterized in that prestress is introduced into the cylindrical peripheral wall by tensioning the PC steel material in the circumferential direction inserted through the cylindrical peripheral wall to form the PC liquid barrier.

Further, the method for constructing the PC tank according to the present invention is as follows.
Construction to construct a PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate. It's a method
A cylindrical peripheral wall is erected along the outer circumference of the foundation plate,
A panel-like shape is formed in a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion, with mounting holes corresponding to anchor bolts provided in the cylindrical peripheral wall in advance. Place reinforcements made of fiber reinforced concrete or fiber reinforced mortar,
The cylindrical peripheral wall and the reinforcing portion are integrated by fastening the cylindrical peripheral wall through the mounting hole of the reinforcing portion via the anchor bolt.
It is characterized in that prestress is introduced into the cylindrical peripheral wall by tensioning the PC steel material in the circumferential direction inserted through the cylindrical peripheral wall to form the PC liquid barrier.

Further, the PC tank according to the present invention is
A PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate.
The PC liquid levee
A cylindrical peripheral wall erected along the outer circumference of the foundation plate,
A reinforcing portion made of fiber reinforced concrete or fiber reinforced mortar and provided integrally with the cylindrical peripheral wall only on the upper end portion, the lower end portion, or only the upper end portion and the lower end portion of the outer peripheral surface of the cylindrical peripheral wall. When,
It is characterized by comprising a PC steel material which is inserted in the circumferential direction of the cylindrical peripheral wall and is tensioned to introduce prestress into the cylindrical peripheral wall.

At this time, the reinforcing portion is formed in advance in a panel shape with a fixing member for integrating with the cylindrical peripheral wall arranged toward the cylindrical peripheral wall.
It is integrated with the concrete placed when the cylindrical peripheral wall is formed in a state of being arranged as a part of the formwork on a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion. It may be made into concrete.

Further, the reinforcing portion is formed in a panel shape in a state in which a mounting hole corresponding to a fixing member for integrating with the cylindrical peripheral wall provided in the cylindrical peripheral wall is previously provided.
The fixing member is fastened to a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion with the fixing member inserted through the mounting hole so as to be integrated with the cylindrical peripheral wall. You may.

According to the present invention, a reinforcing portion made of fiber reinforced concrete or fiber reinforced mortar, which is cheaper than PC steel, is provided with at least one of the upper end portion and the lower end portion, which is a portion where an outer tensile bending moment is generated in the vertical direction. By providing pinpoints at both parts, it is possible to effectively prevent the occurrence of cracks due to the bending moment along the vertical direction in the PC liquid barrier while achieving low cost and facilitation of construction.

At this time, the formwork is placed on at least one or both of the upper end and the lower end of the outer circumference of the cylindrical peripheral wall where the bending moment in the vertical direction is generated, and the fiber reinforced concrete or fiber reinforced concrete is placed in the gap between them. Formwork for casting a cylindrical peripheral wall by casting a fiber reinforced mortar to form it, or forming it into a panel shape by the precast method with fixing members such as gibber bars and anchor bolts placed in advance. By arranging it as a part or forming it into a panel shape in advance by the precast method with the mounting holes corresponding to the fixing members provided on the cylindrical peripheral wall penetrated, the cylinder can be easily constructed. It can be integrated in a state of being firmly joined to the formwork wall.

According to the present invention, it is possible to effectively prevent the occurrence of cracks due to the bending moment along the vertical direction in the PC liquid barrier while achieving low cost and facilitation of construction.

The PC tank according to this embodiment is shown, (a) is a vertical sectional view thereof, and (b) is a horizontal sectional view along the line AA. It is a vertical sectional view which shows the main part in the PC tank of FIG. 1A enlarged. The main part of the PC tank of FIG. 2 is shown, (a) is a plan view showing an enlarged part shown by A, and (b) is a plan view showing an enlarged part shown by B. It is a vertical cross-sectional view provided for the explanation of the construction method of the PC tank which concerns on this embodiment. It is a vertical cross-sectional view which shows the main part of the PC tank which concerns on the modification by enlargement. It is a vertical cross-sectional view which shows the main part of the PC tank which concerns on the modification by enlargement. It is a vertical cross-sectional view which provides the explanation of the construction method of the PC tank which concerns on the modification. It is a vertical cross-sectional view which provides the explanation of the construction method of the PC tank which concerns on the modification. It is a vertical cross-sectional view which shows the lower end part of the PC tank which concerns on the modification by being enlarged.

Hereinafter, embodiments of the PC tank and the method for constructing the PC tank according to the present invention will be described with reference to the accompanying drawings. The present invention can be appropriately modified within the scope of the claims and within a range not contrary to the gist or idea of the invention that can be read from the entire specification, and a PC tank and a method for constructing the same are also the present invention. It is included in the technical idea of.

As shown in FIGS. 1 and 2, in the PC tank 1 according to the present embodiment, a tank body 4 for storing LNG composed of an outer tank 2 and an inner tank 3 and a tank body 4 are placed, and a foundation pile K is mounted. A foundation slab 5 that is rigidly coupled to a plurality of foundation piles K and a PC that is erected along the outer circumference of the foundation slab 5 so as to surround the tank body 4 and has prestressed concrete introduced in the circumferential direction. It has a liquid barrier 6 and.

On the side of the tank body 4, a side cold insulation material Q made of granular pearlite or the like is interposed between the outer tank 2 and the inner tank 3, and glass wool is provided on the side surface of the inner tank 3 on the side cold insulation material Q side. 31 is provided. Further, a cold resistance relaxation portion (PUF) 21 is provided on the side surface of the outer tank 2 on the Q side of the cold insulating material.

Here, in the case of the present embodiment, the PC liquid barrier 6 is different from the conventional PC liquid barrier, for example, a PC steel material for introducing prestress along the vertical direction at the upper end portion A shown in FIG. It is configured without insertion.

Specifically, as shown in FIGS. 2 and 3, the PC liquid barrier 6 has a vertical direction as in the conventional case at the upper end A of the outer periphery of the concrete cylindrical peripheral wall 7 erected on the foundation plate 5. A reinforcing portion 8 (see FIG. 3A) made of fiber reinforced concrete or fiber reinforced mortar is provided integrally with the cylindrical peripheral wall 7 in place of the PC steel material of the above. Further, in the PC liquid barrier 6, the PC steel material 9 in the circumferential direction inserted through the cylindrical peripheral wall 7 and the lower portion of the outer periphery of the cylindrical peripheral wall 7 arranged vertically at the lower end B are U-shaped. It is provided with a PC steel material 10 (see FIG. 3B), and is composed of reinforced concrete as a whole. Then, by tensioning the PC steel material 9 in the circumferential direction and the PC steel material 10 in the vertical direction, prestress is introduced into the cylindrical peripheral wall 7 in the circumferential direction and the vertical direction, and the outer peripheral surface at the upper end A of the cylindrical peripheral wall 7 is introduced. Is reinforced by the reinforcing portion 8 to construct a PC liquid barrier 6 that ensures liquidtightness.

The high-strength fiber reinforced material 12 forming the reinforcing portion 8 has a compressive strength characteristic value of 150 N / mm ² or more, a crack generation strength characteristic value of 4 N / mm ² or more, and a tensile strength characteristic value of 5 N / mm. Fiber reinforced concrete or fiber reinforced mortar with ^two or more performance.

To construct the PC tank 1, first, the foundation slab 5 is constructed on the foundation pile K, and the cylindrical peripheral wall 7 is erected along the outer circumference of the foundation slab 5. In order to erect the cylindrical peripheral wall 7, the wall main body of the cylindrical peripheral wall 7 may be extended upward from the base 70 constituting the foundation plate 5.

At this time, prior to placing concrete, a circumferential sheath pipe (not shown) for inserting the PC steel material 9, a vertical sheath pipe (not shown) and a reinforcing bar (not shown) for inserting the PC steel material 10 are inserted. Is arranged in advance. After placing the concrete, the lower surface of the cylindrical peripheral wall 7 is integrally formed with the foundation plate 5.

Next, as shown in FIG. 4, in the upper end portion A of the cylindrical peripheral wall 7 extending upward from the base portion 70, a fixing member such as a gibber bar 71 is previously attached to the reinforcing portion 8 at the planned arrangement position of the reinforcing portion 8. Place it facing the side. Then, the formwork 11 is arranged on the outer periphery of the cylindrical peripheral wall 7 which is the planned arrangement position of the reinforcing portion 8, and the fiber reinforced concrete or the fiber reinforced mortar which is the high-strength fiber reinforcing material 12 is placed in the gap between them. The reinforcing portion 8 is formed by casting a thin cross section of about 3 cm).

Next, the PC steel materials 9 and 10 are inserted through the cylindrical peripheral wall 7, and then a tension force is introduced into the PC steel materials 9 and 10. In this way, prestress is introduced into the cylindrical peripheral wall 7 in a triangular distribution that can withstand the tension force of the PC steel materials 9 and 10, for example, the hydraulic pressure increasing in the depth direction. With the introduction of the prestress, the cylindrical peripheral wall 7 functions as a PC liquid barrier 6.

As described above, according to the PC tank 1 and the construction method thereof according to the present embodiment, the cylindrical peripheral wall 7 is erected along the outer periphery of the foundation plate 5, and at least of the outer periphery of the cylindrical peripheral wall 7. Fiber reinforced concrete or fiber reinforced mortar as the high-strength fiber reinforcing material 12 was cast into one or both of the upper end portion and the lower end portion (in this case, the upper end portion A) to construct the reinforcing portion 8. As a result, in the PC tank 1 according to the present embodiment, instead of the vertically required PC steel material 10 in the cylindrical peripheral wall 7, fiber reinforced concrete or fiber reinforced mortar which is cheaper than the PC steel material 10 is used. By providing the reinforcing portion 8 at the upper end portion A, which is a portion of the cylindrical peripheral wall 7 where a bending moment is generated in the vertical direction, the reinforcement portion 8 is provided in the vertical direction of the PC liquid barrier 6 while achieving low cost and facilitation of construction. It is possible to effectively prevent the occurrence of cracks due to the bending moment along the line.

In this way, by eliminating the need to introduce prestress along the vertical direction into the PC liquid barrier 6, which was indispensable in the past, the sheath pipes required for prestress introduction can be arranged vertically and the sheath pipes can be introduced. It is possible to construct the PC liquid barrier 6 in a short construction period by omitting the insertion of the PC steel material 10 and the tension work thereof.

In the above-described embodiment, the reinforcing portion 8 is provided integrally with the cylindrical peripheral wall 7 at the upper end portion A shown in FIG. 2 in place of the PC steel material 10 in the vertical direction in the outer periphery of the cylindrical peripheral wall 7. However, the present invention is not limited to this, and the reinforcing portion 8 may be provided at least at one or both of the upper end portion A and the lower end portion B shown in FIG.

For example, as shown in FIGS. 5 or 6 in which the corresponding portions corresponding to those in FIG. 2 are designated by the same reference numerals, the reinforcing portion 8 is provided on both the upper end portion A and the lower end portion B of the outer periphery of the cylindrical peripheral wall 7. It may be provided. At this time, the reinforcing portion 8 may be arranged flush with the outer peripheral surface of the cylindrical peripheral wall 7 (FIG. 5), or may be arranged so as to project from the outer peripheral surface of the cylindrical peripheral wall 7 (FIG. 6). .. In any case, by providing the reinforcing portion 8 instead of the vertical PC steel material 10 at the upper end portion A of the cylindrical peripheral wall 7, the PC steel material 10 arranged here can be eliminated, and further, the cylindrical peripheral wall 7 can be eliminated. Since the amount of the PC steel material 10 in the vertical direction arranged here can be reduced by providing the reinforcing portion 8 at the lower end portion of the cylinder, the material cost can be significantly reduced. Further, although not shown, by providing a reinforcing portion 8 having a strength corresponding to the bending moment in the vertical direction at the lower end portion B of the cylindrical peripheral wall 7, the PC steel material 10 arranged therein can be completely eliminated. It is possible to further reduce the material cost. In addition, although not shown, a reinforcing portion 8 having a strength corresponding to a bending moment in the vertical direction is provided on the entire outer circumference of the cylindrical peripheral wall 7, and the PC steel material 10 in the vertical direction at the upper end portion and the lower end portion is completely eliminated. You may do so. In this case, the work of arranging the PC steel material 10 in the vertical direction, which has been troublesome in the past, is eliminated, and only the simple construction of providing the reinforcing portion 8 is performed, and the fiber reinforced concrete or fiber which is cheaper than the PC steel material 10 is used. Since it can be replaced with the reinforcing portion 8 made of reinforced mortar, it is possible to secure the prevention of cracks due to the bending moment along the vertical direction of the PC liquid barrier 6 while ensuring low cost and ease of construction.

Further, in the above-described embodiment, the reinforcing portion 8 is arranged in advance on the upper end portion A of the outer periphery of the cylindrical peripheral wall 7, and the gibber reinforcement 71 is arranged in advance toward the position where the reinforcing portion 8 is planned to be arranged, and the formwork 11 is placed. Although the case where the fiber reinforced concrete or the fiber reinforced mortar which is the high-strength fiber reinforcing material 12 is poured into the gap between them and formed by casting is described, the present invention is not limited to this.

For example, as shown in FIG. 7, the reinforcing portion 8 is formed in a panel shape by a precast method in a state where a fixing member such as a gibber bar 81 is arranged in advance toward the cylindrical peripheral wall 7, and the panel-shaped reinforcing portion is formed. 8 is arranged as a part of the formwork at a position where the reinforcing portion 8 is planned to be arranged in the formwork (not shown) forming the cylindrical peripheral wall 7. Then, when concrete is cast in this state to form the cylindrical peripheral wall 7, the cylindrical peripheral wall 7 and the reinforcing portion 8 may be fixed and integrally provided via the gibber bar 81.

Further, as shown in FIG. 8 in which the corresponding portions corresponding to those in FIG. 4 are designated by the same reference numerals, fixing members such as anchor bolts 72 toward the reinforcing portion 8 are provided at the positions where the reinforcing portion 8 is to be arranged on the cylindrical peripheral wall 7. The reinforcing portion 8 which has been arranged in advance and is formed in a panel shape by the precast method in a state where the mounting hole 8a corresponding to the anchor bolt 72 is penetrated is a position where the reinforcing portion 8 is to be arranged on the cylindrical peripheral wall 7. The reinforcing portion 8 may be integrated with the cylindrical peripheral wall 7 by fastening the nut 82 to the anchor bolt 72 through which the mounting hole 8a is inserted.

In this way, the reinforcing portion 8 is panelized by the precast method with the gibber bars 81 arranged in advance toward the cylindrical peripheral wall 7, or the panel is provided by the precast method with the mounting holes 8a corresponding to the anchor bolts 72. By arranging the cylindrical peripheral wall 7 as a part of the formwork when driving it, or by fastening it with an anchor bolt 72 and a nut 82 provided on the cylindrical peripheral wall 7, while ensuring ease of construction, It can be integrated with the cylindrical peripheral wall 7 in a state of being firmly joined.

Further, in the above-described embodiment, the PC liquid barrier 6 is shown in the case where the outer peripheral surface of the lower end portion B of the cylindrical peripheral wall 7 is formed vertically, but the present invention is not limited to this, for example, FIG. As shown in 9, the reinforcing portion 8 at the lower end may be formed in a shape that is inclined outward toward the base 70.

1 ... PC tank, 2 ... outer tank, 3 ... inner tank, 4 ... tank body, 5 ... basic plate, 6 ... PC liquid barrier, 7 ... cylindrical peripheral wall, 70 ... base, 71 ... gibber muscle (fixing member) , 72 ... Anchor bolt (fixing member), 8 ... Reinforcing part, 8a ... Mounting hole, 81 ... Jibel reinforcement (fixing member), 82 ... Nut (fixing member), 9 ... Circumferential PC steel material, 10 ... Vertical direction PC steel, 11 ... formwork, 12 ... high-strength fiber reinforced concrete (fiber reinforced concrete or fiber reinforced mortar), K ... pile

Claims (6)

Construction to construct a PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate. It's a method
A cylindrical peripheral wall is erected along the outer circumference of the foundation plate,
A formwork is placed at a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion with a gap from the outer periphery, and fiber reinforced concrete or fiber reinforced mortar is placed in the gap to reinforce the outer circumference. A portion is provided integrally with the cylindrical peripheral wall via a fixing member provided in advance on the cylindrical peripheral wall.
A method for constructing a PC tank, which comprises tensioning a PC steel material in the circumferential direction inserted through the cylindrical peripheral wall to introduce prestress into the cylindrical peripheral wall to form the PC liquid barrier. Construction to construct a PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate. It's a method
When the cylindrical peripheral wall is erected along the outer periphery of the foundation slab, the cylindrical peripheral wall is previously provided only on the upper end portion, the lower end portion, or the upper end portion and the lower end portion of the outer peripheral surface of the cylindrical peripheral wall. A reinforcing portion made of fiber reinforced concrete or fiber reinforced mortar formed in a panel shape with the fixing member arranged toward the surface is placed as a part of the formwork, and concrete is cast to form the cylindrical peripheral wall. Stand up,
A method for constructing a PC tank, which comprises tensioning a PC steel material in the circumferential direction inserted through the cylindrical peripheral wall to introduce prestress into the cylindrical peripheral wall to form the PC liquid barrier. Construction to construct a PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate. It's a method
A cylindrical peripheral wall is erected along the outer circumference of the foundation plate,
A panel-like shape is formed in a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion, with mounting holes corresponding to anchor bolts provided in the cylindrical peripheral wall in advance. Place reinforcements made of fiber reinforced concrete or fiber reinforced mortar,
The cylindrical peripheral wall and the reinforcing portion are integrated by fastening the cylindrical peripheral wall through the mounting hole of the reinforcing portion via the anchor bolt.
A method for constructing a PC tank, which comprises tensioning a PC steel material in the circumferential direction inserted through the cylindrical peripheral wall to introduce prestress into the cylindrical peripheral wall to form the PC liquid barrier. A PC tank including a tank body, a foundation plate on which the tank body is placed, and a PC liquid barrier erected so as to surround the tank body along the outer circumference of the foundation plate.
The PC liquid levee
A cylindrical peripheral wall erected along the outer circumference of the foundation plate,
A reinforcing portion made of fiber reinforced concrete or fiber reinforced mortar, which is provided integrally with the cylindrical peripheral wall only on the upper end portion, the lower end portion, or only the upper end portion and the lower end portion of the outer peripheral surface of the cylindrical peripheral wall. When,
A PC tank comprising: a PC steel material which is inserted in the circumferential direction of the cylindrical peripheral wall and is tensioned to introduce prestress into the cylindrical peripheral wall. The reinforcing portion is formed in advance in a panel shape in a state where a fixing member for integrating with the cylindrical peripheral wall is arranged toward the cylindrical peripheral wall.
It is integrated with the concrete placed when the cylindrical peripheral wall is formed in a state of being arranged as a part of the formwork on a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion. The PC tank according to claim 4, wherein the PC tank is made of concrete. The reinforcing portion is formed in a panel shape in a state in which a mounting hole corresponding to a fixing member for integrating with the cylindrical peripheral wall provided in the cylindrical peripheral wall is previously provided.
The fixing member is fastened to a portion of the outer periphery of the cylindrical peripheral wall including at least one of the upper end portion and the lower end portion with the fixing member inserted through the mounting hole, and is integrated with the cylindrical peripheral wall. The PC tank according to claim 4.

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