JP2020084607A - Construction method of tank - Google Patents

Abstract

To further shorten a construction period in a construction method of a tank with a double shell structure in which an inner tank is constructed by using a jack-up device.SOLUTION: A construction method of a tank with a double shell structure includes an inner tank construction step of constructing an inner tank by a jack-up device 19. The inner tank construction step includes: a first inner tank construction step of installing a first jack-up device 19A in a middle stage portion of an outer tank 2 and constructing an inner tank up to the middle stage portion by the first jack-up device 19A; and a second inner tank construction step of installing a second jack-up device 19B so as not to interfere with the first jack-up device 19A in a vertical direction in a top portion 2A of the outer tank 2 and constructing the inner tank from the middle stage portion to the top portion 2A by the second jack-up device 19B.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for constructing a tank.

As a method of constructing a tank, in Patent Document 1 below, a step of assembling an inner tank by raising a lift body by a jack-up device inside the outer tank and welding an inner tank side plate to the lower side of the lifted lift body is described. A method of constructing a cylindrical tank having is disclosed. The jack-up device includes a jack body and a jack rod that is stroked by the operation of the jack body.The suspended side mount is attached to the lifting body, and the suspended side mount is attached to the outer tank. Connect the jack body to one of the mounts, and connect the jack rod to the other of the suspended mount and the suspended mount via a washer, and operate the jack body to lift the lifting body via the suspended mount. After raising the lifted body and holding it in the outer tub via the holding means, remove the suspension-side pedestal from the outer tub and lift the suspension-side pedestal together with the jack body or the jack rod and washer. , The mounting position of the suspension side mount to the outer tank is changed to the upper position (suspension side mount position changing process).

JP, 2017-53183, A

In the above-mentioned conventional technique, the inner tank is assembled in accordance with the assembly of the outer tank, and it is necessary to perform the above-mentioned step of changing the mounting position of the suspension side frame about three times. However, since the hanging-side pedestal mounting position changing process requires a work time of several weeks per time, there is a problem that the work period becomes longer as the number of times increases.

The present invention has been made in view of the above problems, and an object of the present invention is to shorten the construction period in a method for constructing a double-shell structure tank in which an inner tank is constructed by a jack-up device.

In order to solve the above problems, the present invention is a method for constructing a tank having a double-shell structure having an inner tank and an outer tank, wherein a jackup device is installed in the outer tank, and the jackup device is used. Ascending of the deep-fried body, and welding of the inner tank side plate to the lower side of the raised deep body has an inner tank building step of alternately repeating to build the inner tank, and the inner tank building step, A first inner tank building step of installing a first jack-up device in the middle part of the outer tank, and building the inner tank up to the middle part by the first jack-up device, and a top part of the outer tank. A second inside in which a second jack-up device is installed so as not to interfere with the first jack-up device in the vertical direction, and the inner tank is constructed from the middle-stage part to the top part by the second jack-up device. The method of having a tank construction process is adopted.

Further, in the present invention, a method is employed in which the first jack-up device and the second jack-up device are installed at equal intervals in the circumferential direction of the tank.

Further, in the present invention, a method of alternately installing the first jack-up device and the second jack-up device in the circumferential direction of the tank is adopted.

Further, in the present invention, the jack-up device includes a jack main body and a jack rod that is stroked by the operation of the jack main body. In the inner tank building step, the jack main body is attached to the outer tank, A method of attaching the jack rod to the lift body is adopted.

Further, in the present invention, a method is adopted in which the stroke of the jack rod of the second jackup device partially overlaps the stroke of the jack rod of the first jackup device in the vertical direction. To do.

Further, in the present invention, a method of installing the first jack-up device on the inner side in the tank radial direction with respect to the second jack-up device is adopted.

Further, in the present invention, the lift includes a first suspended side mount to which the first jackup device is attached, and a second suspended side mount to which the second jackup device is attached, And the first suspended-side mount is smaller than the second suspended-side mount.

According to the present invention, the construction period can be shortened in the method of constructing a double shell structure tank in which the inner tank is constructed by the jack-up device.

It is explanatory drawing which shows the 1st process of the construction|assembly method in 1st Embodiment of this invention. It is explanatory drawing which shows the 2nd process of the construction|assembly method in 1st Embodiment of this invention. It is an enlarged view showing a jackup device in a 1st embodiment of the present invention. It is explanatory drawing which shows the 3rd process of the construction|assembly method in 1st Embodiment of this invention. It is a top view showing arrangement of the 1st jackup device and the 2nd jackup device in a 1st embodiment of the present invention. FIG. 6 is a view on arrow A in FIG. 5. It is explanatory drawing which shows the 4th process of the construction|assembly method in 1st Embodiment of this invention. It is explanatory drawing which shows the 5th process of the construction|assembly method in 1st Embodiment of this invention. It is explanatory drawing which shows the 6th process of the construction|assembly method in 1st Embodiment of this invention. It is a top view showing arrangement of the 1st jackup device and the 2nd jackup device in a 2nd embodiment of the present invention. It is a side view which shows arrangement|positioning of the 1st jackup apparatus in 2nd Embodiment of this invention.

Hereinafter, a method for constructing a tank according to the present invention will be described with reference to the drawings. In the following description, a construction method of a ground type PC (prestressed concrete) double shell storage tank for storing LNG will be exemplified. In the following drawings, some parts are enlarged or omitted for convenience of explanation, and the dimensional ratios of the respective constituent elements shown in the drawings are not always the same as the actual ones.

(First embodiment)
FIG. 1 is an explanatory diagram showing a first step of the construction method according to the first embodiment of the present invention.
First, in this method, as shown in FIG. 1, a substantially disc-shaped base plate 1 is constructed. The base plate 1 is made of concrete, and an inner tank anchor strap 4 and a corner angle 100 are buried in the outer peripheral edge portion thereof.

Next, in this method, the outer tank 2 is constructed on the basic plate 1. The outer tank 2 is built on the outer peripheral edge of the foundation plate 1. The outer tub 2 is a PC (prestressed concrete) wall constructed by assembling the outer tub side plate 3 on the upper end of the corner angle 100 by welding and placing concrete 5 using the outer tub side plate 3 as an inner mold. is there. That is, the inner wall surface 2 a of the outer tank 2 is formed by the outer tank side plate 3.

The assembling of the outer tank side plate 3 and the placing of the concrete 5 are performed in parallel with a certain interval. Thereby, the protruding portion of the outer tank side plate 3 at a height where the concrete 5 is not cast can be suppressed within a certain range. Since the protruding portion is a portion where the outer tank side plate 3 alone receives a wind load, it is possible to prevent the outer tank side plate 3 from buckling due to the wind load by limiting the protruding portion to a certain range.

In this method, the bottom liner 6 is laid on the foundation plate 1 in parallel with the construction of the outer tank 2 described above. After that, the portal frame 10 is installed along the outer peripheral edge of the bottom liner 6 (inside the base end of the outer tank 2). The gate-shaped mount 10 supports the lift body 60 (the inner tank side plate 9, the knuckle plate 11, etc.) that constructs the inner tank in the inner tank building step described later (see FIGS. 2 and 4 ).

Under the portal frame 10, a cold insulation structure 12 such as a perlite concrete block or a structural lightweight concrete block is temporarily placed, and cold insulation work of the annular portion 13 (see FIG. 4) by the cold insulation structure 12 is performed. A plurality of the gate-shaped pedestals 10 are installed along the inner side of the base end portion of the outer tub 2, and a cylindrical inner tub formed by combining a plurality of inner tub side plates 9 should be finally lowered onto the foundation plate 1. It is installed so as to straddle the annular region X which is a region.

FIG. 2 is an explanatory diagram showing a second step of the construction method according to the first embodiment of the present invention.
Next, in this method, the knuckle plate 11 is assembled on the portal frame 10. The knuckle plate 11 connects the outer peripheral edge of the inner tank roof 14 and the upper end of the inner tank side plate 9. Further, in this method, the roof pedestal 7 is assembled in the central portion of the foundation plate 1 in parallel with the installation of the gate-shaped pedestal 10 and/or the assembly of the knuckle plate 11. During this period, the outer tank 2 can be constructed while the scaffold 6b is installed.

The inner tank roof 14 is assembled on the roof mount 7. Then, the knuckle plate 11 assembled on the gate-shaped mount 10 is attached to the outer peripheral edge of the inner tank roof 14. In addition, if the dome-shaped lift body 60 in which the knuckle plate 11 is assembled to the inner tank roof 14 can stand on the gate-type mount 10, the roof mount 7 can be disassembled. Next, in this method, the jackup device 19 is installed in the outer tub 2 in order to jack up the lift 60. The jack-up device 19 is installed between the inner and outer tanks 15 (between the outer tank and the inner tank), and jacks up the lifting body 60.

FIG. 3 is an enlarged view showing the jackup device 19 according to the first embodiment of the present invention.
The jack-up device 19 has a jack main body 19a and a jack rod 19b that makes a stroke by the operation of the jack main body 19a. The jack body 19a is, for example, a center hole jack, and has a piston cylinder (not shown) operated by hydraulic pressure, and a collet desk (not shown) that holds the jack rod 19b vertically moved by the piston cylinder. The jack rod 19b is, for example, a divisible step rod, and has a plurality of step grooves capable of holding the collet desk.

The jack main body 19a is attached to the middle-stage jack support 70 (suspension-side mount) provided in the middle stage of the outer tub 2. Further, the jack rod 19b is attached to the suspended base 80 provided on the lift 60 (the knuckle plate 11) via the washer 19c. In this state, when the jack main body 19a is operated so as to stroke the jack rod 19b upward, the jack rod 19b is connected to the suspended side mount 80, and therefore the lifting body 60 passes through the suspended side mount 80. Rise.

FIG. 4 is an explanatory diagram showing a third step of the construction method according to the first embodiment of the present invention.
After the jack-up device 19 is installed as described above, the lifting body 60 is jacked up by an amount corresponding to the vertical width of the inner tank side plate 9, and the inner tank side plate 9 is carried into the lower space formed by the jacking up. The inner tank side plates 9 are loaded one by one into the inside of the tank through the construction port 8 formed in the outer tank 2.

The inner tank side plate 9 is conveyed to a predetermined welding position on the portal frame 10, the adjacent inner tank side plates 9 are welded to each other, and the inner tank side plates 9 are joined together in the circumferential direction so as to have a cylindrical shape as a whole. Next, the upper end of the inner tank side plate 9 is assembled to the lower end of the knuckle plate 11. Then, the lifting body 19 including the inner tank roof 14, the knuckle plate 11, and the inner tank side plate 9 is again jacked up by an amount corresponding to the vertical width of the inner tank side plate 9.

After raising the lifting body 60 by an amount corresponding to the vertical width of the inner tank side plate 9, the next inner tank side plate 9 is carried into the space formed under the inner tank side plate 9 by jacking up. When the loaded inner tank side plates 9 are joined together in the tank circumferential direction, the upper end portion thereof and the lower end portion (inner tank side plate 9) of the lift body 60 are welded. In this way, the lifting of the lift body 60 by the jack-up device 19 and the welding of the inner tank side plate 9 to the lifted lift body 60 are alternately repeated to build the inner tank (inner tank building step).

This inner tank building step is divided into two steps, a first inner tank building step and a second inner tank building step. As shown in FIG. 4, in the first inner tank building process, the jack-up device 19 (first jack-up device 19A) installed in the middle part of the outer tank 2 via the middle jack support 70 is used to This is a process of constructing an inner tank up to the middle part (see FIG. 4). Here, the middle part of the outer tub 2 is an area of a predetermined width in the middle when the total height of the outer tub 2 (side wall) (from the foundation plate 1 to the top 2A of the outer tub 2) is divided into three equal parts in the vertical direction. Means (intermediate part).

In the second inner tank building process, the jack-up device 19 (second jack-up device 19B) installed on the top 2A of the outer tank 2 via the top jack support 90 is used to move the middle part of the outer tank 2 to the top 2A. This is a step of constructing a tank (see FIG. 7 described later). That is, in this method, after the jack-up by the first jack-up device 19A installed in the middle part of the outer tub 2 is completed, the lifting body 60 is attached to the second jack-up device 19B installed on the top 2A of the outer tub 2. The load is transferred (changed) and the first jack-up device 19A is disassembled.

FIG. 5 is a plan view showing the arrangement of the first jackup device 19A and the second jackup device 19B according to the first embodiment of the present invention. FIG. 6 is a view on arrow A in FIG.
As shown in FIG. 5, the second jackup device 19B is installed so as not to interfere with the first jackup device 19A in the vertical direction. In the present embodiment, the first jack-up device 19A and the second jack-up device 19B are installed at equal intervals in the circumferential direction of the tank and are alternately installed in the circumferential direction of the tank.

Specifically, in the present embodiment, the first jackup device 19A and the second jackup device 19B are installed at the same pitch (P) in the circumferential direction of the tank, and the first jackup device 19A and the first jackup device 19A are installed. The phase of the arrangement of the jackup device 19B of No. 2 is shifted by a half pitch (P/2). Note that the first jack-up device 19A and the second jack-up device 19B may be installed at different pitches and numbers as long as the directions viewed from the center of the tank are deviated. Thereby, the interference between the first jack-up device 19A and the second jack-up device 19B can be avoided.

On the outer peripheral edge of the lifting body 60, in order to accomodate both the first jackup device 19A and the second jackup device 19B, the suspended side mount at half pitch (P/2) intervals in the circumferential direction of the tank. 80 is provided. Here, as shown in FIG. 6, the stroke of the jack rod 19b of the second jack-up device 19B is part of the stroke of the jack rod 19b of the first jack-up device 19A in the up-down direction (range indicated by reference symbol L). It is good that they overlap.

As a result, the load (lifting) of the lift 60 from the first jack-up device 19A to the second jack-up device 19B can be transferred smoothly. That is, the jack rod 19b of the second jackup device 19B can start to be attached to the lift body 60 (suspended side pedestal 80) during the jackup of the first jackup device 19A. For example, if the jack rod 19b of the second jackup device 19B is not provided with the washer 19c and is free with respect to the suspended side pedestal 80, the jackup by the first jackup device 19A may be hindered. No, you can prepare for the refill.

The above-mentioned "installing the first jack-up device 19A and the second jack-up device 19B at equal intervals in the circumferential direction of the tank" does not need to be strictly equal intervals. This is because, for example, the outer tank side plate 3 is arranged in the outer tank 2, and it is necessary to install the outer tank side plate 3 while avoiding the welding line. Further, in the present embodiment, the first jack-up device 19A and the second jack-up device 19B are alternately arranged in the circumferential direction of the tank. However, for example, when the load of the lifting body 60 is biased. The first jack-up device 19A or the second jack-up device 19B may be arranged densely or continuously at that portion.

Returning to FIG. 4, under the portal frame 10, the cold insulation work of the annular portion 13 by the cold insulation structure 12 described above is performed. The cold insulation work of the annular portion 13 is performed, for example, by assembling a perlite concrete block and a structural lightweight concrete block on the bottom cooling/heat resistance mitigating material, and then attaching the annular plate thereon. After the cold insulation work of the annular portion 13 is completed, the leg portion 10a disposed inside the tank with respect to the annular portion 13 is replaced on the annular portion 13.

As a result, since there is no interfering substance inside the tank than the annular portion 13, it is possible to perform the cold insulation work on the central portion of the foundation plate 1. In the cold insulation work in the central portion, the foam glass 40 is placed on the bottom heat resistance relaxation material 39. Then, a perlite concrete block (not shown) and an inner tank bottom plate (not shown) are laid one on top of the other. The outer tank roof 22 (the tank roof) is assembled on the inner tank roof 14. The outer tank roof 22 is connected to the inner tank roof 14 with a connecting member (not shown), and is assembled integrally with the inner tank roof 14.

FIG. 7: is explanatory drawing which shows the 4th process of the construction|assembly method in 1st Embodiment of this invention.
When the load of the lift 60 is transferred to the second jackup device 19B, the first jackup device 19A is removed as shown in FIG. Then, the raising of the lift body 60 by the second jack-up device 19B and the welding of the next inner tank side plate 9 to the lower side of the raised lift body 60 are alternately repeated, and the lowermost stage of the inner tank side plate 9 is moved. The first structure 9a to be removed is assembled.

In this method, the lowermost stage of the inner tank side plate 9 is assembled on the annular portion 13 separately from the first structure 9a. After disassembling the portal frame 10, after placing the lowermost stage of the inner tank side plates 9 on the annular portion 13, the adjacent inner tank side plates 9 are welded together and joined together in the circumferential direction so as to be cylindrical as a whole, The second structure 9b is assembled. After assembling the second structure 9b, the inner tank anchor strap 4 installed on the foundation plate 1 is attached. Further, an elevating staircase 23 is provided outside the outer tub 2. Further, the pump barrel 25 is carried into the outer tank 2.

FIG. 8: is explanatory drawing which shows the 5th process of the construction|assembly method in 1st Embodiment of this invention.
Next, in this method, as shown in FIG. 8, the first structure 9a is jacked down, the lower end of the first structure 9a is lowered to the upper end of the second structure 9b, and the first structure 9a is lowered. The inner structure 30 is assembled by welding the structure 9a and the second structure 9b. In this method, the lowermost assembly of the inner tank 30 is separated from the assembly of the inner tank 30 by the jack-up device 19, and the second structure 9b, which is the lowermost step of the inner tank 30, is fixed onto the annular portion 13. Are moving ahead of schedule. Therefore, in this method, the fixing of the inner tank 30 onto the annular portion 13 which takes about one month does not have to be a critical path.

FIG. 9 is an explanatory diagram showing a sixth step of the construction method according to the first embodiment of the present invention.
When the inner tank 30 is completed, the outer tank roof 22 is disconnected from the inner tank roof 14 by a connecting member (not shown) and installed on the upper end of the outer tank 2 assembled to the uppermost stage. Further, the second jackup device 19B is removed. Further, roof stairs 24 are provided on the outer tank roof 22. Further, the pump barrel 25 is installed.
Tension construction of the outer tank 2 is appropriately performed, and after the construction mouth 8 is closed, water filling is performed and a pressure-proof/airtight test is performed. Finally, the cold insulation material 44 is arranged between the inner and outer tanks 15 between the inner tank 30 and the outer tank 2, and the cold insulation material 44 is also arranged between the inner tank roof 14 and the outer tank roof 22 to perform cold insulation work. (Cooling material arranging step), and the LNG tank 50 is constructed through painting work and pipe cooling work.

As described above, according to the above-described present embodiment, the LNG tank 50 having the double shell structure having the inner tank 30 and the outer tank 2 is constructed by installing the jack-up device 19 in the outer tank 2, There is an inner tank building step of building the inner tank 30 by alternately repeating the lifting of the lift 60 by the jack-up device 19 and the welding of the inner tank side plate 9 to the lower side of the lifted lift 60. The tank building process includes a first inner tank building process in which the first jack-up device 19A is installed in the middle part of the outer tank 2 and the inner tank 30 is built up to the middle part by the first jack-up device 19A. A second jack-up device 19B is installed on the top 2A of the tank 2 so as not to interfere with the first jack-up device 19A in the vertical direction, and the inner tank 30 from the middle stage to the top 2A is installed by the second jack-up device 19B. By adopting the method of having the second inner tank construction step of constructing, the load of the lifting body 60 can be transferred (replaced) only once, so that the construction period can be shortened.

Further, in the present embodiment, the jack body 19a is attached to the outer tub 2 and the jack rod 19b is attached to the lifting body 60. The jack body 19a may be attached to the lifting body 60. However, as shown in FIG. 2 of the above-mentioned conventional technique (Japanese Patent Laid-Open No. 2017-53183), the jack rod 19b is moved downward when jacking up. Since it extends (remains), the inner tank side plate 9 (uppermost stage) is pre-assembled on the gate-type mount 10 and the knuckle plate is mounted on it in order to secure a lower working space. It is necessary to mount 11. Further, it is necessary to reinforce the inner tank side plate 9 (uppermost stage) to mount the knuckle plate 11. However, if the jack body 19a is attached to the outer tub 2, the jack rod 19b does not extend downward (does not remain) at the time of jacking up, so that the above-mentioned pre-assembly and reinforcement of the inner tub side plate 9 are unnecessary, and As shown in FIG. 2, the knuckle plate 11 can be pre-assembled. Further, there is an advantage that the height of the roof pedestal 7 can be lowered by the preceding assembly of the knuckle plate 11, and the height required for an aerial work vehicle for constructing the inner tank roof 14 and the like can be reduced.

(Second embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent configurations as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be simplified or omitted.

FIG. 10 is a plan view showing the arrangement of the first jackup device 19A and the second jackup device 19B according to the second embodiment of the present invention. FIG. 11 is a side view showing the arrangement of the first jackup device 19A in the second embodiment of the present invention.
In the second embodiment, as shown in FIGS. 10 and 11, the first jack-up device 19A is installed on the inner side in the tank radial direction than the second jack-up device 19B. different.

As shown in FIG. 10, the lifting body 60 of the second embodiment has a first suspended side pedestal 80A to which the first jack-up device 19A is attached and a second suspended-side pedestal 80A to which the second jack-up device 19B is attached. The suspended side frame 80B. The first suspended side pedestal 80A corresponds to the arrangement of the first jack-up device 19A, and is disposed closer to the center of the tank than the second suspended side pedestal 80B in plan view. Further, in this connection, the middle-stage jack support 70 that supports the first jack-up device 19A extends inward in the tank radial direction as compared with the first embodiment described above.

When viewed from the side view shown in FIG. 11, the first suspended side pedestal 80A is engaged with the jack rod 19b above the knuckle plate 11 with respect to the second suspended side pedestal 80B. That is, since the knuckle plate 11 is curved toward the inner side in the tank radial direction (the inner tank roof 14 side) as it goes toward the upper end portion thereof, if the engagement position of the jack rod 19b is changed to the inner side in the tank radial direction, it naturally comes out. The mating position is changed to the upper side of the knuckle plate 11.

The engagement position of the first suspended side pedestal 80A with respect to the jack rod 19b in the tank radial direction is shifted inward in the tank radial direction by a distance D from the engagement position of the second suspended side pedestal 80B. Assuming that the distance D is, for example, 1.5 m between the side wall 2 and the lifting body 60, and the jack rod 19b of the second jackup device 19B is located at an intermediate position of the clearance, for example, It is good to have 0.5 meters or more. In addition, the position where the first suspended side pedestal 80A is attached to the jack rod 19b may be on the knuckle plate 11.

The first suspended side pedestal 80A is smaller than the second suspended side pedestal 80B. In the present embodiment, the total height H1 of the first suspended side mount 80A is about half the total height H2 of the second suspended side mount 80B. The first suspended side pedestal 80A is arranged closer to the knuckle plate 11 than the second jackup device 19B, because the first suspended side pedestal 80A is disposed inside the second jackup device 19B in the tank radial direction. Then, since the moment load applied to the base side (the knuckle plate 11 side) of the first suspended side pedestal 80A is reduced by pulling up the jack rod 19b, the size is made smaller than that of the second suspended side pedestal 80B. -Can be lightened.

According to such a second embodiment, the first jack-up device 19A is installed on the inner side of the second jack-up device 19B in the tank radial direction, so that the distance from the outer tank 2 can be maintained. . Therefore, the installation of the first jack-up device 19A, that is, the work of mounting the hydraulic jack in the middle part of the outer tub 2 is facilitated. Further, the work on the inner peripheral surface of the outer tub 2 (for example, the welding work or repair of the outer tub side plate 3 or the skin fitting work) is facilitated. Furthermore, since the first suspended-side pedestal 80A is smaller than the second suspended-side pedestal 80B, it can be easily transported and installed, and its manufacturing cost can be reduced.

The preferred embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above embodiments. The shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

For example, the first jack-up device 19A constructs the inner tub 30 up to the middle stage of the outer tub 2, so even if a down-sized one having a smaller lift is used than the second jack-up device 19B. Good.

2 Outer tank 9 Inner tank side plate 10 Gate-type mount 11 Knuckle plate 12 Cooling structure 13 Annular portion 14 Inner tank roof 19 Jack-up device 19A First jack-up device 19B Second jack-up device 19a Jack body 19b Jack rod 30 Inner tank 50 LNG tank (tank)
60 Lifting body 80A First suspended side mount 80B Second suspended side mount

Claims (7)

A method for constructing a double-shell structure tank having an inner tank and an outer tank,
A jack-up device is installed in the outer tank, and the lifting of the lift body by the jack-up device and the welding of the inner tank side plate to the lower side of the lifted lift body are alternately repeated to build the inner tank. Has an internal tank construction process to
The inner tank construction step,
A first inner tank building step of installing a first jack-up device in the middle part of the outer tank, and building the inner tank to the middle part by the first jack-up device;
A second jack-up device is installed on the top of the outer tank so as not to interfere with the first jack-up device in the vertical direction, and the inner tank extends from the middle stage to the top by the second jack-up device. And a second inner tank building step of building a tank. The method for constructing a tank according to claim 1, wherein the first jack-up device and the second jack-up device are installed at equal intervals in the circumferential direction of the tank. The method for constructing a tank according to claim 1, wherein the first jack-up device and the second jack-up device are alternately installed in a circumferential direction of the tank. The jack-up device includes a jack body and a jack rod that is stroked by the operation of the jack body,
The method for constructing a tank according to any one of claims 1 to 3, wherein in the inner tank building step, the jack body is attached to the outer tank and the jack rod is attached to the lift body. .. The stroke of the jack rod of the second jack-up device partially overlaps the stroke of the jack rod of the first jack-up device in the up-down direction. How to build a tank. The method for constructing a tank according to claim 1, wherein the first jack-up device is installed on the inner side in the tank radial direction with respect to the second jack-up device. The lift body includes a first suspended side mount to which the first jackup device is attached, and a second suspended side mount to which the second jackup device is attached,
The method for constructing a tank according to claim 6, wherein the first suspended side mount is smaller than the second suspended side mount.

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