JP6931600B2 - Ground tank - Google Patents

Description

The present invention relates to a ground tank.

Ground tanks are sometimes used as equipment for storing low-temperature liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas).

FIG. 6 shows an example of an LNG tank 100 that stores LNG as a ground tank. The LNG tank 100 is a tank frame in which a liquid barrier 6 is fixed on a bottom slab 5 supported by piles 4 in the ground 7, and an inner tank 3a and an outer tank steel plate 3b made of steel plates or the like are provided inside the tank skeleton. be. LNG is stored in the inner tank 3a, and the heat insulating material 8 is arranged between the inner tank 3a and the outer tank steel plate 3b to keep it cool. The outer tank steel plate 3b is integrally formed with the liquid barrier 6. Reinforcing bars, heater tubes (not shown), and the like are also provided in the bottom plate 5.

The liquid barrier 6 is a concrete side wall provided to prevent liquid leakage from the LNG to the outside when the inner tank 3a is damaged, and is usually cylindrical. The liquid barrier 6 needs to have a structure that can withstand the hydraulic pressure of LNG, and is therefore rigidly coupled to the bottom slab 5, and is not shown in the tank circumferential direction (hereinafter, may be simply referred to as the circumferential direction) tension material or vertical direction. A tension force (pre-stress) due to the tension material of the concrete is introduced to generate a predetermined compressive stress (cross-sectional force) in the concrete.

When the tension material is tensioned in the circumferential direction with the liquid barrier 6 rigidly connected to the bottom slab 5, the bending moment in the vertical plane that tries to bend the liquid barrier 6 inside the tank (bending moment of tension on the outside of the liquid barrier). ) Is generated at the bottom of the liquid barrier 6, so it is necessary to arrange an amount of vertical tension material necessary for canceling the liquid barrier 6.

On the other hand, as one of the construction methods of the above-ground tank, there is a method of rigidly connecting the liquid barrier and the bottom slab after tensioning the tension material in the circumferential direction while the bottom of the liquid barrier is free. When the tension material in the circumferential direction is strained after the liquid barrier and the bottom slab are rigidly bonded, the movement and rotation of the lower end of the liquid barrier inward are hindered by the bottom slab, and the bending moment in the vertical plane is generated. Since this is not the case with the method, the amount of tension material in the circumferential direction can be reduced, and the amount of tension material in the vertical direction can also be reduced.

For example, in Patent Document 1, the bottom slab is constructed by dividing it into an outer peripheral portion and a central portion, and a gap is provided between them. The outer peripheral part of the bottom slab is only placed on the foundation pile, and a liquid barrier is constructed integrally with the outer peripheral part, and the tension material in the circumferential direction is strained when the liquid barrier is almost completed. After that, the gap between the outer peripheral portion and the central portion of the bottom slab is filled with padded concrete, and the radial tension material of the bottom slab passed from the outer edge of the central portion of the bottom slab to the inside of the outer peripheral portion of the bottom slab is tensioned to make the outer peripheral portion of the bottom slab the central portion. Attract to the side and integrate the outer circumference of the bottom slab with the foundation pile.

Japanese Unexamined Patent Publication No. 2014-167244

When the tension material is tensioned in the circumferential direction while the bottom of the liquid barrier is free to introduce tension, and then the liquid barrier and the bottom slab are rigidly coupled, the free to rigid coupling is performed after the tension in the circumferential direction is introduced. The structural system changes to. When such a structural system change occurs, the section force generated by the introduction of the tension force in the circumferential direction changes from the section force in the free state to the section force in the rigidly bonded state due to the creep and drying shrinkage of concrete. Transition (decrease) by about 50 to 60% (for example, Nippon Road Association "Road Bridge Specification / Explanation I Common Edition Chapter 2 2.2.5 Effect of Concrete Creeping and Drying Shrinkage", March 2002 ).

Further, in the method of Patent Document 1, an unstable state in which a liquid barrier is constructed on the outer peripheral portion of the bottom slab placed on the foundation pile in a free state continues for a long time, and finally the outer peripheral portion of the bottom slab is formed. The work of fixing to the foundation pile under the bottom slab is also quite difficult. In addition, a tension material in the tank radial direction is required to integrate the outer peripheral portion of the bottom slab into the central portion, and it is necessary to connect reinforcing bars and heater pipes between the outer peripheral portion and the central portion of the bottom slab, and concrete filling work is also required. Occurs.

Furthermore, when LNG leaks, the temperature of the bottom slab also drops because the LNG comes into contact with the top surface of the bottom slab. At this time, the bottom slab tries to shrink in temperature, and this temperature shrinkage is constrained by piles and liquid barriers. As a result, a tensile force is generated in the concrete of the bottom slab, but the method of Patent Document 1 cannot leave a compressive stress that can cancel the tensile force in the concrete at the center of the bottom slab.

The present invention has been made in view of the above problems, and provides a above-ground tank capable of effectively introducing the tension force due to the tension material in the circumferential direction to the side wall and the bottom slab and easily generating compressive stress. The purpose.

The first invention for solving the above-mentioned problems is a above-ground tank having a tank skeleton including a bottom slab and a side wall, the bottom slab is provided separately for an upper layer bottom slab and a lower layer bottom slab, and the side wall is the upper layer bottom slab. A tension force in the circumferential direction of the tank is introduced into the side wall, and a step portion having a stepped upper surface position is formed on the outer peripheral portion of the lower layer bottom slab. A thickened portion was formed below the portion, the thickened portion was arranged on the stepped portion, and a slip bar was arranged between the wall surface of the stepped portion and the inner peripheral surface of the thickened portion . It is a ground tank characterized by this.
The second invention is a above-ground tank having a tank skeleton including a bottom slab and a side wall, the bottom slab is provided separately for an upper layer bottom slab and a lower layer bottom slab, and the side wall is rigidly connected to the upper layer bottom slab and is attached to the side wall. A tension force in the circumferential direction of the tank was introduced, and a step portion in which the position of the upper surface was lowered in a stepped manner was formed on the outer peripheral portion of the lower layer bottom slab, and the outer peripheral portion of the upper layer bottom slab was thickened below the central portion. A thickened portion is formed, the thickened portion is arranged on the stepped portion, and the lower end of an anchor strap extending from an inner tank provided inside the tank skeleton is embedded in the thickened portion. It is a ground tank.

In the present invention, the bottom slab of the tank skeleton is constructed separately as the upper bottom slab and the lower bottom slab, and the upper bottom slab rigidly connected to the side wall is thinned. Even when the upper bottom slab is rigidly connected, the tension force of the tension material in the circumferential direction of the side wall can be introduced in a state where the bottom of the side wall is almost free. Moreover, in this case, the structural system is almost the same when the tension material in the circumferential direction is strained and when the tank frame is completed (the upper bottom slab and the side wall continue to be rigidly connected), so that the cross-sectional force shifts due to creep and drying shrinkage. Almost none. Therefore, the tension force due to the tension material in the circumferential direction can be effectively introduced, the amount of the tension material in the circumferential direction can be reduced, and at the same time, the amount of the tension material in the vertical direction can be reduced. Further, in the present invention, it is possible to leave compressive stress in the upper bottom slab due to the tension of the tension material in the circumferential direction.

Further, in the present invention, since the side wall is rigidly connected to the upper bottom slab of the lower bottom slab and raised, the construction of the side wall is stable, and the lower bottom slab may also be fixed on the pile from the beginning. Further, in the present invention, since the central portion and the outer peripheral portion of the bottom slab are not divided, the tensioning material in the tank radial direction described above is not required, and the connecting work of reinforcing bars and heater pipes and the filling work of concrete are also unnecessary.

In the present invention, a stepped portion whose upper surface is stepped down is formed on the outer peripheral portion of the lower layer bottom slab, and a thickened portion thickened below the central portion is formed on the outer peripheral portion of the upper layer bottom slab. , more and this to the increase thickness portion is disposed on the stepped portion, it is possible to the position of the upper bottom plate suitably secured to the lower deck slabs.

It is desirable that the joint material is arranged between the wall surface of the stepped portion and the inner peripheral surface of the thickened portion.
When the tension material in the circumferential direction is tense, the side wall and the thickening part move inward, causing the joint material to shrink, filling the gap between the wall surface of the step and the inner peripheral surface of the thickening part to stop water. It will be possible to do.

Further, it is desirable that the sheet material is arranged between the upper surface of the stepped portion and the lower surface of the thickened portion.
As a result, the side wall and the thickened portion can be easily moved inward when the tension material in the circumferential direction is tensioned.

In the first aspect of the invention, more and this slip bar is disposed between the inner peripheral surface of the increased thickness portion and the wall surface of the stepped portion, it is possible to prevent the lifting of the upper bottom plate.

In the second invention, it is possible to lower the anchor strap extending from the provided bath inside the tank skeleton is more and this is embedded in the increase thickness portion, placing the inner tank stably anchor Installation of the strap is also easy.

It is desirable that a haunch is formed on the outside of the bottom of the side wall.
Thereby, the side wall can be reinforced.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a above-ground tank in which the tension force due to the tension material in the circumferential direction can be effectively introduced into the side wall and the bottom slab and it is easy to generate compressive stress.

The figure which shows the LNG tank 1. The figure which shows the cross section in the thickness direction of the bottom of the liquid barrier 2. The figure which shows the slip bar 56 and the sealant 58. The figure which shows the construction method of the LNG tank 1. The figure which shows the slit 20. The figure which shows the LNG tank 100.

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

(1. LNG tank 1)
FIG. 1 is a diagram showing an LNG tank 1 which is a above-ground tank according to an embodiment of the present invention.

The LNG tank 1 is a ground tank having a size of about 200,000 KL for storing LNG (low temperature liquid) inside, and like the LNG tank 100 described with reference to FIG. 6, the bottom slab supported by the pile 4 in the ground 7. The liquid barrier 2 is fixed on the 5 to form a tank skeleton, and an inner tank 3a and an outer tank steel plate 3b are provided inside the tank skeleton. The liquid barrier 2 is a cylindrical side wall rigidly coupled to the bottom slab 5 and is provided to prevent liquid leakage from the LNG to the outside when the inner tank 3a is damaged. The liquid barrier 2 is constructed of concrete having a predetermined tensile strength, and has an inner diameter of about 80 m and a height of about 40 m.

The LNG tank 1 is a PC (prestressed concrete) tank, and a tensioning force due to a tensioning material in the circumferential direction of the tank and a tensioning material in the vertical direction is introduced into the liquid barrier 2 as described later.

On the outside of the bottom of the liquid barrier 2, the haunch 2a extends along the circumferential direction of the tank. The haunch 2a is a right-angled triangular cross-sectional portion that is widened outward with respect to an equal-thickness portion 2b having a constant thickness (for example, about 0.6 m) above the haunch 2a. The outer surface of the haunch 2a inclines linearly with respect to the vertical direction toward the outside as it goes downward, and the thickness of the bottom of the liquid barrier 2 including the haunch 2a is about 1.2 m. Here, "outside" means the outside of the tank, and "inside" means the inside of the tank. The height range in which the haunch 2a is provided varies depending on the design, but for example, the height of the haunch 2a from the bottom plate 5 is set to about 5.0 m.

In the present embodiment, the bottom slab 5 is provided in two layers, and has an upper bottom slab 5a and a lower bottom slab 5b. The liquid barrier 2 is integrated with the upper bottom slab 5a and rigidly coupled, and the pile 4 is integrated with the lower bottom slab 5b and rigidly coupled.

FIG. 2 is a view showing a cross section of the bottom portion of the liquid barrier 2 in the thickness direction. The upper bottom slab 5a has a configuration in which the central portion 50 is thin and the outer peripheral portion thereof is a thickened portion 52 having a thickness larger than that of the central portion 50, and these are in the tank circumferential direction (depth in FIG. 2). It has a continuous shape (corresponding to the direction).

The upper end of the upper bottom plate 5a has the same height in the central portion 50 and the thickening portion 52, and the thickening portion 52 is thickened below the central portion 50. The liquid barrier 2 is rigidly coupled onto the thickened portion 52. The central portion 50 is thinner than the equal-thickness portion 2b of the liquid barrier 2, for example, about 0.2 m. The thickness of the thickened portion 52 is, for example, about 0.7 m. The length of the thickened portion 52 in the tank radial direction is, for example, about 2.1 m.

The lower bottom slab 5b supports the load of the LNG tank 1, and a step portion 53 is formed on the outer peripheral portion. The step portion 53 is a portion where the position of the upper surface is stepped lower than the central portion 51 inside the step portion 53. The thickening portion 52 of the upper bottom plate 5a is arranged in this step portion 53. The step of the step portion 53 is, for example, about 0.5 m, and the length in the tank radial direction is about 2.2 m.

A rubber plate 54 having a thickness of about 5.0 mm is provided as a sheet material between the upper surface of the step portion 53 and the lower surface of the thickening portion 52. However, the present invention is not limited to this, and instead of the rubber plate 54, another sheet material such as a civil engineering sheet may be laid to cut the edge.

Further, a gap is provided between the wall surface of the step portion 53 and the inner peripheral surface of the thickening portion 52, and the joint material 55 is arranged in this gap. An elastic body such as Styrofoam or a soft rubber plate is used for the joint material 55.

In the liquid barrier 2, a circumferential PC steel material 11 which is a tension material in the tank circumferential direction and vertical PC steel materials 13 and 15 which are vertical tension materials are provided.

A plurality of PC steel materials 11 in the circumferential direction are provided at intervals above and below, and are arranged from the thickened portion 52 of the upper bottom slab 5a to the top of the liquid barrier 2. The circumferential PC steel 11 is arranged along the vertical PC steel 13.

The vertical PC steel material 13 is provided in the vertical direction inside the circumferential PC steel material 11. The vertical PC steel 13 is arranged from the top of the liquid barrier 2 to the thickened portion 52 of the upper bottom slab 5a, and is arranged at a position substantially in the center of the equal thickness portion 2b in the thickness direction.

The vertical PC steel material 15 is arranged diagonally along the outer surface of the haunch 2a. The lower end of the vertical PC steel 15 is fixed in the thickened portion 52 of the upper bottom plate 5a, and the upper end is fixed in the equal thickness portion 2b of the liquid barrier 2.

The specifications, placement and tension of these PC steels are determined by the design. In addition, each PC steel material is arranged in a sheath (not shown), and mortar is filled between the sheath and the PC steel material. However, for the vertical PC steel material 15, the sheath may be omitted as the unbonded PC steel material.

Anchor straps 31 such as steel plates are arranged on the side wall portion of the inner tank 3a over the entire circumference of the inner tank 3a. The anchor strap 31 is provided for the purpose of preventing the inner tank 3a from floating, and its lower end is embedded in the thickened portion 52 of the upper bottom plate 5a.

FIG. 3A is a diagram showing the range A of FIG. As shown in FIG. 3A, between the wall surface of the stepped portion 53 of the lower bottom slab 5b and the inner peripheral surface of the thickened portion 52 of the upper bottom slab 5a, the horizontal direction embedded in the thickened portion 52 of the upper bottom slab 5a. The slip bar 56 of the above penetrates the joint material 55 and is inserted into the sheath tube 57 embedded in the lower bottom slab 5b. The sheath tube 57 may be filled with grease or the like.

FIG. 3B is a diagram showing the range B of FIG. As shown in FIG. 3B, a sealing material 58 is provided on the outside of the rubber plate 54 at the outer edge of the boundary between the upper surface of the stepped portion 53 of the lower bottom slab 5b and the lower surface of the thickened portion 52 of the upper bottom slab 5a. The boundary portion (rubber plate 54) is protected from the outside world. At this outer edge, the concrete of the upper bottom slab 5a and the lower bottom slab 5b is chamfered to form the chamfered portion 59 when the sealing material 58 is installed.

When constructing the LNG tank 1, as shown in FIG. 4A, the lower layer bottom slab 5b having the stepped portion 53 is constructed, and the rubber plate 54 and the joint material 55 described above are arranged. The thickness of the joint material 55 is about 50 mm. After that, as shown in FIG. 4B, the upper bottom slab 5a is constructed, and the liquid barrier 2 above it is constructed at a partial height (for example, a height of 10 m or more) or the entire height.

In the present embodiment, after the concrete of the lower bottom slab 5b is cast, the surface of the central portion 51 is smoothed by performing trowel finishing or the like, and after the concrete is hardened, the concrete of the upper bottom slab 5a is cast. As a result, the central portion 51 of the lower bottom slab 5b is also cut off from the central portion 50 of the upper bottom slab 5a, and between the concrete of the central portion 51 of the lower bottom slab 5b and the concrete of the central portion 50 of the upper bottom slab 5a. It is configured so that stress is not transmitted. The edge may be cut more reliably by providing the edge cutting layer by spraying the spray material or arranging the sheet material or the like at the central portion 50 of the lower layer bottom plate 5b.

After that, by introducing the tension force by the circumferential PC steel material 11, the liquid barrier 2 moves slightly inward (about 10 to 20 mm) as shown by the arrow C in FIG. 4 (b). Since the upper bottom plate 5a is thin and has low rigidity, it contracts and deforms with almost no resistance to this movement. Further, the rubber plate 54 and the joint material 55 do not restrain the movement of the liquid barrier 2, and the slip bar 56 (see FIG. 3A) is placed in the sheath pipe 57 of the lower bottom slab 5b without resistance when the liquid barrier 2 moves. Go through.

After that, the tension force due to the vertical PC steel materials 13 and 15 is introduced into the liquid barrier 2. Hereinafter, the LNG tank 1 is constructed by performing installation work on the inner tank 3a, the outer tank steel plate 3b, and the like. Note that 32 in FIG. 4B is a cavity provided in the thickened portion 52 of the upper bottom plate 5a for inserting the lower end of the anchor strap 31, and after the lower end of the anchor strap 31 is inserted and fixed during the construction of the inner tank 3a. It is filled with a filler such as mortar (not shown).

According to the present embodiment described above, the bottom slab 5 of the tank skeleton is constructed separately as the upper bottom slab 5a and the lower bottom slab 5b, and the upper bottom slab 5a rigidly connected to the liquid barrier 2 is thinned. Since the rigidity of 5a is small and it can be easily contracted, even when the liquid barrier 2 and the upper bottom slab 5a are rigidly connected, the tension force of the circumferential PC steel 11 is applied to the bottom of the liquid barrier 2 which is almost free. Can be introduced at. Moreover, in this case, the structural system is almost the same when the circumferential PC steel material 11 is tense and when the tank frame is completed (the upper bottom slab 5a and the liquid barrier 2 continue to be rigidly connected), so that the cross section due to creep and drying shrinkage continues. There is almost no power transfer. Therefore, the tension force due to the circumferential PC steel 11 can be effectively introduced, and the amount of the circumferential PC 11 can be reduced, and at the same time, the amounts of the vertical PC steels 13 and 15 can also be reduced.

Further, in the present embodiment, it is possible to leave compressive stress in the upper bottom slab 5a due to the tension of the circumferential PC steel material 11. Therefore, the tensile force when the temperature of the upper bottom slab 5a drops at the time of LNG leakage can be canceled by this compressive stress.

Further, in the present embodiment, since the liquid barrier 2 is rigidly connected to the upper bottom plate 5a of the lower bottom plate 5b and raised, the arrangement of the liquid barrier 2 is stable, and the lower bottom plate 5b is also placed on the pile 4. You can fix it from the beginning. Further, in the present embodiment, since the central portion and the outer peripheral portion of the bottom slab 5 are not divided, the tensioning material in the tank radial direction described above is not required, and the connecting work of reinforcing bars and heater pipes and the filling work of concrete are not required. be.

Further, in the present embodiment, since the thickening portion 52 of the outer peripheral portion of the upper layer bottom plate 5a is arranged on the step portion 53 provided on the outer peripheral portion of the lower layer bottom plate 5b, the position of the upper layer bottom plate 5a is suitably fixed to the lower layer bottom plate 5b. However, it can be prevented from slipping. Further, since the central portion 50 of the upper bottom slab 5a is placed on the central portion 51 of the lower bottom slab 5b, the central portion 50 of the upper bottom slab 5a is bent downward (central portion) due to the tension of the circumferential PC steel material 11. It is also possible to prevent the occurrence of bending) in which 50 is convex downward.

Further, in the present embodiment, when the circumferential PC steel material 11 is tense, the liquid barrier 2 and the thickening portion 52 move inward, so that the joint material 55 contracts, and the wall surface of the step portion 53 and the thickening portion 52 It becomes possible to preferably stop water by filling the gap between the inner peripheral surfaces. However, it is also possible to omit the joint material 55 to form a hollow gap.

Further, in the present embodiment, since the rubber plate 54 is arranged between the lower surface of the thickening portion 52 and the upper surface of the stepped portion 53, the liquid barrier 2 and the thickening portion 52 move inward when the PC steel material 11 in the circumferential direction is tense. Can be easily moved.

Further, in the present embodiment, the upper bottom slab 5a is connected to the lower bottom slab 5b by the slip bar 56, and the thickened portion 52 of the upper bottom slab 5a does not rise even in the event of an earthquake or the like. However, it is also possible to omit the slip bar 56.

Further, in the present embodiment, since the lower end of the anchor strap 31 extending from the metal inner tank 3a is embedded in the thickening portion 52, the inner tank 3a can be stably installed, and in the event of an earthquake or the like. It is possible to prevent the tank 3a from rising. In addition, the anchor strap 31 can be easily installed.

Further, in the present embodiment, the haunch 2a is formed on the outside of the bottom of the liquid barrier 2, whereby the liquid barrier 2 can be reinforced.

However, the present invention is not limited to this. For example, as shown in FIG. 5 showing the outer surface of the liquid barrier 2, the haunch 2a may be provided with a slit 20 in the vertical direction. The slits 20 are provided at predetermined intervals in the tank circumferential direction, and the haunch 2a is divided in the tank circumferential direction by the slits 20. The width of the slit 20 is smaller than the installation interval of the slit 20 described above.

As a result, the rigidity of the bottom portion of the liquid barrier 2 is reduced, and the tension force in the circumferential direction of the tank due to the tension of the PC steel material 11 in the circumferential direction is received by the portion of the liquid barrier 2 other than the haunch 2a. The amount of the PC steel material 11 can be reduced, and the amount of the vertical PC steel materials 13 and 15 can also be reduced. A slit material (not shown) is arranged in the slit 20, and the outside thereof is sealed by the sealing material 24. As the slit material, in addition to a wooden board such as plywood, an elastic body such as a hard rubber board, polyurethane foam, or styrofoam can be used.

Further, by providing an edge cutting material such as a sheet between the haunch 2a and the upper bottom slab 5a, it is possible to cut the edge between the haunch 2a and the upper bottom slab 5a to further reduce the rigidity and reduce the amount of the circumferential PC steel material 11. be. Cutting the edges of the upper bottom slab 5a and the lower bottom slab 5b to reduce the adhesive force between them is also effective in reducing the amount of the circumferential PC steel material 11.

Further, the shape of the haunch 2a is not limited to the one having a right-angled triangular cross section, and may be a rectangular shape or the like. In this case as well, the vertical PC steel material is arranged in the haunch in the vertical direction or diagonally as in the vertical PC steel material 15. In some cases, the haunch may be provided inside the liquid barrier 2, or the haunch may be omitted.

Furthermore, the present invention is not limited to LNG tank 1, and can be applied to so-called PC tanks that introduce tension in the circumferential direction of the tank. It may be water or the like.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

1,100: LNG tank 2,6: Liquid barrier 2a: Haunch 2b: Equal thickness 3a: Inner tank 3b: Outer tank Steel plate 4: Pile 5: Bottom slab 5a: Upper bottom slab 5b: Lower bottom slab 6: Liquid barrier 7 : Ground 8: Insulation material 11: Circumferential PC steel material 13, 15: Vertical PC steel material 20: Slit 24, 58: Sealing material 31: Anchor strap 50, 51: Central part 52: Thickening part 53: Step part 54: Rubber plate 55: Joint material 56: Slip bar 57: Sheath tube 59: Chamfered part

Claims (5)

A ground tank with a tank skeleton that includes a bottom slab and side walls.
The bottom slab is separately provided as an upper bottom slab and a lower bottom slab.
The side wall is rigidly connected to the upper bottom plate,
A tension force in the circumferential direction of the tank is introduced into the side wall ,
On the outer peripheral portion of the lower layer bottom slab, a step portion in which the position of the upper surface is lowered in a stepped manner is formed.
A thickened portion thickened below the central portion is formed on the outer peripheral portion of the upper layer bottom slab.
The thickening portion is arranged on the step portion, and the thickening portion is arranged.
A above-ground tank characterized in that a slip bar is arranged between the wall surface of the stepped portion and the inner peripheral surface of the thickened portion. A ground tank with a tank skeleton that includes a bottom slab and side walls.
The bottom slab is separately provided as an upper bottom slab and a lower bottom slab.
The side wall is rigidly connected to the upper bottom plate,
A tension force in the circumferential direction of the tank is introduced into the side wall ,
On the outer peripheral portion of the lower layer bottom slab, a step portion in which the position of the upper surface is lowered in a stepped manner is formed.
A thickened portion thickened below the central portion is formed on the outer peripheral portion of the upper layer bottom slab.
The thickening portion is arranged on the step portion, and the thickening portion is arranged.
A above-ground tank characterized in that the lower end of an anchor strap extending from an inner tank provided inside the tank skeleton is embedded in the thickened portion. The above-ground tank according to claim 1 or 2, wherein a joint material is arranged between the wall surface of the step portion and the inner peripheral surface of the thickened portion. Ground tank according to any one of claims 1 to claim 3, characterized in that the sheet material is disposed between the lower surface of the increased thickness portion and the upper surface of the stepped portion. The above-ground tank according to any one of claims 1 to 4 , wherein a haunch is formed on the outside of the bottom of the side wall.

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