JP2019070295A - Tank construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for constructing a tank capable of streamlining the work of laying an inner tank bottom plate. SOLUTION: This is a method of constructing a tank having a double shell structure having an inner tank construction step of constructing an inner tank inside the outer tank, and the inner tank construction step is a method of constructing an inner tank bottom on which an inner tank bottom plate is laid. It has an inner tank bottom construction process to be constructed, and in the inner tank bottom construction process, a carry-in stand is installed inside the outer tank, and the inner tank is inside the outer tank from the construction port formed in the outer tank via the carry-in stand. The inner tank bottom plate loading process for loading the bottom plate, and the inner tank bottom plate laying process for laying the inner tank bottom plate so that the longitudinal direction of the inner tank bottom plate follows the opening direction of the construction port, at least in the installation area of the loading stand. Adopt the method of having. [Selection diagram] FIG. 5

Description

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

  A double shell tank having an inner tank and an outer tank is used for storage of low temperature liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas). Patent Document 1 below discloses an LNG storage tank having an inner tank made of metal and an outer tank made of concrete.

  The LNG storage tank is provided with a liquid-repellent embankment made of PC (prestressed concrete) in which a compressive force is given in advance in a substantially vertical direction and a circumferential direction to PC steel, and the outer tank side so as to substantially cover the inside of the liquid-proof dike The outer tank formed by arranging the inner liner plates and the inner tank side plates made of steel containing 7% nickel are connected in the circumferential direction so that the vertical connection lines do not overlap. And an inner tank formed by step-stacking and welding the connecting portion at the longitudinal joint and the circumferential joint.

  Between the inner tank and the outer tank, a heat insulating layer filled with perlite and / or PUF (polyurethane foam) is formed. In addition, a bottom plate liner plate is laid on a base slab of the tank, and a bottom cold storage layer formed by laminating perlite concrete, foam glass, ALC (lightweight aerated concrete), heat resistant board and the like is formed thereon. An inner tank bottom plate is laid on the bottom cold storage layer, whereby an inner tank bottom is constructed.

JP, 2014-193726, A

  The above-mentioned prior art inner tank bottom plate laying is performed as follows. First, install a roller conveyor on the stage outside the tank at the construction opening and a slope at the construction opening in the tank. Then, using a crane or the like, the inner tank bottom plate is placed on the roller conveyor on the stage and pulled onto the slope. Thereafter, it is lowered by a slope, the inner tank bottom plate is moved to a predetermined position, and arranged along the marking. From the place where the arrangement is completed, the surface alignment, the groove welding and the like are sequentially performed (see paragraph 0063 of Patent Document 1 and FIG. 13).

  By the way, since such a loading rack (such as the slope of Patent Document 1) is installed in the tank, it interferes with the laying of the inner tank bottom plate, and unless the loading rack is removed, the installation area of the loading rack. Could not lay the inner tank bottom plate. Since the construction of the inner tank bottom is not completed until the inner tank bottom plate is laid in the installation area of the loading rack, it is required to make the laying operation of the inner tank bottom plate more efficient.

  This invention is made in view of the said problem, and an object of this invention is to provide the construction method of the tank which can streamline the installation operation | work of an inner tank bottom plate.

  In order to solve the above problems, the present invention is a method of constructing a double shell tank having an inner tank construction step of constructing an inner tank inside an outer tank, wherein the inner tank construction step It has an inner tank bottom construction process which builds an inner tank bottom in which a tank bottom plate was laid, and the above-mentioned inner tank bottom construction process installs a carrying-in racket inside the above-mentioned outer tank, and construction opening formed in the above-mentioned outer tank The inner tank bottom plate carrying-in step of carrying the inner tank bottom plate into the outer tank from the inside through the carry-in cradle, and the longitudinal direction of the inner tank bottom plate at least in the installation area of the carry-in cradle is the opening of the construction opening An inner tank bottom plate laying step of laying the inner tank bottom plate in a direction following the direction.

  Further, in the present invention, the inner tank constructing step includes an inner tank sidewall constructing step of constructing an inner tank sidewall in which an inner tank side plate is assembled, and the inner tank sidewall constructing step is performed inside the outer tank. The first raising of the inner tank side plate by the jack-up device and the attachment of the next inner tank side plate to the lower side of the raised inner tank side plate are alternately repeated, excluding the lowermost stage of the inner tank side wall A first inner tank side wall constructing step of assembling a structure, and a second inner tank assembling a second structure which is the lowermost stage of the inner tank side wall on an annular portion provided on a peripheral portion of the inner tank bottom. And a third inner tank side wall construction step of joining the first structure and the second structure and assembling the inner tank side wall, the inner tank bottom portion construction step Is performed in parallel with the inner tank side wall construction step, and at least In front of the vessel side wall construction process employing a technique called ends.

  In the present invention, in the inner tank bottom plate laying step, a first inner tank bottom plate laying step of laying the inner tank bottom plate in a region other than the installation region of the carry-in racket; And a second inner tank bottom plate laying step of laying the inner tank bottom plate in a region where the carry-in racket has been installed after the carry-in racket removal step of removing the carry-in racket and after the carry-in racket removal step. Adopt a method called

  Further, in the present invention, a method is adopted in which the length in the longitudinal direction of the carry-in racket is shorter than the length in the longitudinal direction of the inner tank bottom plate laid in the installation area of the carry-in racket.

  According to the present invention, since the inner tank bottom plate is laid in a direction in which the longitudinal direction of the inner tank bottom plate follows the opening direction of the construction opening at least in the installation region of the carry-in rack, the inner tank bottom plate laid after removal of the carry-in rack The number of sheets can be reduced, and the laying work of the inner tank bottom plate can be made efficient.

It is an explanatory view showing the 1st process of a construction method in an embodiment of the present invention. It is an explanatory view showing the 2nd process of a construction method in an embodiment of the present invention. It is explanatory drawing which shows the 3rd process of the construction method in embodiment of this invention. It is a plane schematic diagram which shows the inner tank bottom plate laid in the inner tank bottom part in embodiment of this invention. FIG. 5 is an enlarged detail view showing an installation area of the loading rack shown in FIG. 4 and an inner tank bottom plate laid in the vicinity of the area. It is a plane schematic diagram which shows the inner tank bottom plate laid in the conventional inner tank bottom part as a comparative example. FIG. 7 is an enlarged detail view showing an installation area of the loading rack shown in FIG. 6 and an inner tank bottom plate laid in the vicinity of the area. It is explanatory drawing which shows the 4th process of the construction method in embodiment of this invention. It is an explanatory view showing the 5th process of a construction method in an embodiment of the present invention. It is explanatory drawing which shows the 6th process of the construction method in embodiment of this invention.

  Hereinafter, the tank and the method of constructing the tank according to the present invention will be described with reference to the drawings. The following description exemplifies a method of constructing a land-type PC (prestressed concrete) double shell storage tank for storing LNG. In the following drawings, some parts are enlarged or omitted for convenience of explanation, and the dimensional ratio of each component shown in the drawings is not necessarily the same as the actual one.

FIG. 1 is an explanatory view showing a first step of a construction method in the embodiment of the present invention. 1 (a) is an overall view, and FIG. 1 (b) is an enlarged view of a region A shown in FIG. 1 (a).
First, in the present method, as shown in FIG. 1 (a), a substantially disk-shaped basic version 1 is constructed (basic version construction step). The base plate 1 is made of concrete, and the inner tank anchor strap 4 and the corner angle 100 are embedded in the outer peripheral edge thereof.

  Next, in the present method, the outer tank 2 is constructed on the basic version 1 (outer tank construction step). As shown in FIG. 1A, the outer tank 2 is constructed at the peripheral portion of the substantially disk-shaped base plate 1. The outer tank 2 is a PC wall constructed by casting concrete 5 with the outer tank side plate 3 as an inner form while assembling the outer tank side plate 3 (side plate) to the upper end of the corner angle 100 by welding. Therefore, a plurality of outer tank side plates 3 are arranged on the inner wall surface 2 a of the outer tank 2.

  As shown in FIG. 1 (b), the corner angle 100 is formed in an L-shape in cross section. At the lower part of the corner angle 100, a head stud 101 for applying a pull-out load to the base plate 1 is joined so that the outer tank side plate 3 welded to the upper end is not inclined. A separator cone 102 for installing the outer frame 200 may be joined to the rear surface of the corner angle 100.

  The outer tank side plate 3 is formed in a rectangular plate shape. A stiffener 110 is joined to the surface 3a of the outer tank side plate 3 facing the inner side of the tank and the back surface 3b on the opposite side. The stiffener 110 is embedded in the concrete 5. Further, a separator cone 120 for installing the outer frame 200 is joined to the back surface 3 b of the outer tank side plate 3. The outer mold frame 200 is connected to the outer tank side plate 3 via the separator 201 connected to the separator cone 120.

  The outer tank side plate 3 has a lateral stiffener 110A and a longitudinal stiffener 110B as stiffeners 110. The lateral stiffener 110A is embedded in the concrete 5 so as to extend in the horizontal direction, and increases the shear resistance of the outer tank side plate 3 due to prestress. The longitudinal stiffener 100B is embedded in the concrete 5 so as to extend in the vertical direction, and suppresses the expansion of the outer tank side plate 3 to the inside of the tank due to the placing pressure of the concrete 5.

  The assembling of the outer tank side plate 3 and the placing of the concrete 5 are parallel operations at a fixed interval. Thereby, the protrusion part P of the outer tank side plate 3 of the height which is not pouring concrete 5 can be restrained to a certain fixed range. Since the protruding portion P is a portion that receives the wind load by the outer tank side plate 3 alone, it is possible to prevent the buckling of the outer tank side plate 3 due to the wind load by thus suppressing the protruding portion P within a certain range.

FIG. 2 is an explanatory view showing a second step of the construction method in the embodiment of the present invention.
In the present method, the bottom liner 6 is laid on the base plate 1 in parallel with the assembly of the outer tank 2. Moreover, the roof mount 7 is assembled in the center part of the foundation version 1. Further, a construction port 8 for taking in the inner tank side plate 9 and the like is formed at the base end of the outer tank 2. Moreover, along the inside of the base end part of the outer tank 2, multiple gate type mount frames 10 for inner tank side plate assembly are installed. The portal type gantry 10 is installed so as to straddle an annular region X, which is a region where a cylindrical inner tank formed by combining a plurality of inner tank side plates 9 is to be finally lowered onto the base plate 1.

  Under the portal frame 10, a cold storage structure 12 such as a pearlite concrete block or a lightweight structural concrete block is temporarily placed in the annular area X. Further, on the portal frame 10, a plurality of jackup devices 19 are installed in the outer tank 2. Specifically, the suspension-side gantry 70 is installed in the middle portion of the outer tank 2 above the installation position of the portal-type gantry 10. The suspension-side gantry 70 is detachably fastened and fixed to an anchor plate (not shown) embedded in the outer tank 2. Further, the suspended support frame 80 is installed on the knuckle plate 11 assembled on the portal frame 10.

  The jack main body 19 a of the jack-up device 19 is connected to the to-be-suspended side support frame 80. In addition, a jack rod 19b which is stroked by the operation of the jack main body 19a is connected to the suspension stand 70. After the jack-up device 19 is thus installed, the knuckle plate 11 is lifted from the portal frame 10, the inner tank side plate 9 is carried into the lower space created by the jack up, and adjacent inner tank side plates 9 are welded to each other. The pieces are joined together in the circumferential direction so that they become cylindrical as a whole. Next, the upper end portion of the inner tank side plate 9 is assembled to the lower end portion of the knuckle plate 11. Further, the upper end portion of the knuckle plate 11 is assembled to the outer peripheral edge portion of the inner tank roof 14 which has been folded on the roof mount 7.

FIG. 3 is an explanatory view showing a third step of the construction method in the embodiment of the present invention.
Thereafter, in order to construct the inner tank side wall 31, the lifting body 60 including the inner tank roof 14, the knuckle plate 11 and the inner tank side plate 9 is lifted by the jack-up device 19 (inner tank side wall constructing step). In the inner tank side wall construction step, lift body 60 is lifted, roof frame 7 is removed, jack-up of lift body 60 (equivalent to the vertical width of inner tank side plate 9) and lower end of inner body 60 (inner tank side plate 9) Repeat the attachment (welding) of the next inner tank side plate 9 to) alternately and assemble the first structure 9a excluding the lowermost stage of the inner tank side wall 31 while reintroducing the jack point on the hanging side upward () 1st inner tank side wall construction process).

Also, during this process, the outer tub roof 22 is assembled on the inner tub roof 14. The outer tank roof 22 is connected to the inner tank roof 14 by a connecting member (not shown), and is integrally assembled with the inner tank roof 14.
Under the portal frame 10, a cooling work of the annular portion 13 by the temporarily placed cold storage structure 12 is performed. When the cold insulation work of the annular portion 13 is completed, as shown in FIG. 3, the leg portion 10 a of the portal type gantry 10 arranged on the tank inner side than the annular portion 13 is replaced on the annular portion 13.

  As a result of such replacement, no interference is present on the inner side of the tank with respect to the annular portion 13, so that the cooling work of the central portion on the basic version 1 can be performed. In the central cold storage construction, a bottom thermal resistance relaxation material 39 (for example, a pearlite concrete block) is placed on the bottom liner 6, and the foam glass 40 is placed thereon. Furthermore, an ALC (lightweight aerated concrete) and a heat resistant board (both not shown) are sequentially stacked thereon, and finally an inner tank bottom plate 41 is laid thereon to construct an inner tank bottom portion 32 (inner tank bottom portion construction Process).

FIG. 4 is a schematic plan view showing the inner tank bottom plate 41 laid on the inner tank bottom 32 in the embodiment of the present invention.
As shown in FIG. 4, the inner tank bottom plate 41 is laid in a region surrounded by an annular portion 13 provided annularly at the peripheral edge portion of the inner tank bottom portion 32. The inner tank bottom plate 41 is configured by combining two types of inner tank bottom plates 41a and 41b having different directions in the longitudinal direction. The longitudinal direction of the inner tank bottom plate 41a differs by 90 ° from the longitudinal direction of the inner tank bottom plate 41b.

  The inner tank bottom plate 41a is a so-called tatami mat plate whose longitudinal direction is installed along the bottom plate installation reference line L2, and the number thereof is larger than that of the inner tank bottom plate 41b. The inner tank bottom plate 41b is a so-called corridor plate installed with its longitudinal direction orthogonal to the bottom plate installation reference line L2, and is interposed between the inner tank bottom plates 41a adjacent in the longitudinal direction of the inner tank bottom plate 41a. , Avoiding formation of a cruciform joint by butt welding. In addition, the length (width) of the short direction of the inner tank bottom plate 41a (composition board) is substantially the same as the length (width) of the short direction of the inner tank bottom plate 41b (corridor plate). That is, the longitudinal direction of the inner tank bottom plate 41 is a direction orthogonal to the short direction.

  Such an inner tank bottom plate 41 is carried into the outer tank 2 from the construction opening 8a formed in the outer tank 2 (inner tank side plate carrying-in step). The construction opening 8a is a construction opening (so-called small construction opening) provided at a position different from the construction opening 8 (so-called large construction opening) for taking in the inner tank side plate 9 shown in FIGS. 2 and 3 The opening width is equal to or larger than the width of the inner tank bottom plate 41 and smaller than the width of the inner tank side plate 9. The loading of the inner tank bottom plate 41 is performed via a loading rack 90 installed inside the outer tank 2. As the loading rack 90, for example, a roller rack having a plurality of rollers on a support surface is preferably used.

FIG. 5 is an enlarged detail view showing the installation area 91 of the loading rack 90 shown in FIG. 4 and the inner tank bottom plate 41 laid in the vicinity of the area.
The inner tank bottom plate 41 is laid in a direction in which the longitudinal direction of the inner tank bottom plate 41 follows the opening direction of the construction opening 8 a at least in the installation area 91 of the loading rack 90. The opening direction of the construction opening 8a is a direction in which the construction opening reference line L1 extends. The construction opening reference line L1 is a reference line passing through the center of the opening width of the construction opening 8a and the center O of the inner tank bottom portion 32, as shown in FIG.

  The loading rack 90 is installed so that the opening direction of the construction opening 8a coincides with the longitudinal direction. That is, the carry-in rack 90 extends in the opening direction of the construction opening 8a along the construction opening reference line L1. The inner tank bottom plate 41 laid in the installation area 91 of the carry-in rack 90 is an inner tank bottom plate 41a (a folded plate) extending along the bottom plate installation reference line L2. The bottom plate installation reference line L2 is a reference line for laying the inner tank bottom plate 41 which passes through the center O of the inner tank bottom 32 and extends in the radial direction.

  The bottom plate installation reference line L2 is set at an angle α with respect to the construction opening reference line L1. The angle α is preferably 20 ° or less, more preferably 10 ° or less, and further preferably 5 ° or less. Bottom plate installation reference line L2 and construction opening reference line L1 may be matched, and angle α may be set to 0 °. That is, the direction following the opening direction of the construction opening 8a is a direction in which the longitudinal direction of the inner tank bottom plate 41a coincides with or substantially matches the opening direction of the construction opening 8a, and a range of 0 ° ≦ α ≦ 20 °, More preferably, it means the range of 0 ° ≦ α ≦ 10 °, and still more preferably the range of 0 ° ≦ α ≦ 5 °.

In the inner tank bottom plate laying step of laying the inner tank bottom plate 41, first, the inner tank bottom plate 41 is laid in a region other than the installation region 91 of the carry-in rack 90 (first inner tank bottom plate laying step). That is, the inner tank bottom plate 41 other than the inner tank bottom plate 41a1 shown in FIG. 5 is laid in a region other than the installation region 91 of the loading rack 90. Next, the loading rack 90 is removed (loading rack removal process). In addition, before removing the loading rack 90, the inner tank bottom plate 41a1 is carried in to the inside of the outer tank 2 in advance. Finally, the inner tank bottom plate 41a1 which has been carried into the outer tank 2 in advance is laid in a region where the loading rack 90 has been installed (second inner tank bottom plate laying step).
Thus, the inner tank bottom 32 shown in FIG. 4 is constructed.

FIG. 6 is a schematic plan view showing the inner tank bottom plate 41 laid on the conventional inner tank bottom 32A as a comparative example. FIG. 7 is an enlarged detail view showing the installation area 91 of the loading rack 90 shown in FIG. 6 and the inner tank bottom plate 41 laid in the vicinity of the area.
In the comparative example shown in FIG. 6, the relationship between the opening direction of the construction opening 8a and the longitudinal direction of the inner tank bottom plate 41a is not considered at all, and for example, the angle α is 30 ° or more. In such a case, in the second inner tank bottom plate laying step after removal of the loading rack 90 described above, as shown in FIG. 7, five inner tank bottom plates 41a1 as the inner tank bottom plate 41a and an inner tank as the inner tank bottom plate 41b. It is necessary to lay a total of six bottom plates 41b1.

  On the other hand, according to the above-described method, as shown in FIG. 5, in the second inner tank bottom plate laying step after removal of the carry-in rack 90, two inner tank bottom plates 41a1 may be laid as the inner tank bottom plate 41a. That is, in the present method, as shown in FIG. 5, the inner tank bottom plate 41 is laid in a direction in which the longitudinal direction of the inner tank bottom plate 41 follows the opening direction of the construction opening 8a in at least the installation region 91 of the loading rack 90. Therefore, the number of inner tank bottom plates 41a1 to be laid after removal of the carry-in rack 90 can be reduced. In addition, if the width of the inner tank bottom plate 41a1 is sufficient, it is also possible to reduce the number of inner tank bottom plates 41a1 to be laid after removal of the loading rack 90 to a minimum of one. For this reason, according to the present method, the laying operation of the inner tank bottom plate 41 can be made efficient.

  Further, in the present method, as shown in FIG. 5, the length S1 in the longitudinal direction of the carry-in rack 90 is shorter than the length S2 in the longitudinal direction of the inner tank bottom plate 41a1 laid in the installation area 91 of the carry-in rack 90 As in the comparative example shown in FIG. 7, it is not necessary to lay the inner tank bottom plate 41 b (corridor plate) after removal of the loading rack 90. Thereby, without waiting for the removal of the loading rack 90, butt welding between the inner tank bottom plate 41a (folding plate) and the inner tank bottom plate 41b (corridor plate) in the area other than the installation area 91 of the loading rack 90 Since it is possible, the laying operation of the inner tank bottom plate 41 can be made more efficient.

FIG. 8 is an explanatory view showing a fourth step of the construction method in the embodiment of the present invention.
In the present method, in parallel with the above-described inner tank bottom construction step, the lowermost stage of the inner tank side plate 9 is assembled on the annular portion 13 separately from the first structure 9a assembled in FIG. Specifically, after dismantling the portal type gantry 10, when the lowermost step of the inner tank side plate 9 is placed on the annular portion 13, adjacent inner tank side plates 9 are welded to form a cylindrical shape as a whole. It joins in a direction and assembles the 2nd structure 9b (2nd inner tank side wall construction process). After the second structure 9 b is assembled, the inner tank anchor strap 4 installed on the foundation plate 1 is attached. In addition, the elevating stairs 23 are provided outside the outer tank 2. In addition, the pump barrel 25 is carried into the outer tank 2.

FIG. 9 is an explanatory view showing a fifth step of the construction method in the embodiment of the present invention.
Next, in the present method, as shown in FIG. 9, the first structure 9a is jacked down, and the lower end of the first structure 9a is lowered to the upper end of the second structure 9b. The structure 9a and the second structure 9b are welded to assemble the inner tank side wall 31 (third inner tank side wall constructing step). In this method, the assembly of the lowermost part of the inner tank side wall 31 is separated from the assembly of the inner tank side wall 31 by the jack-up device 19 and the upper part on the annular portion 13 of the second structure 9b which is the lowermost part of the inner tank side wall 31. We are going to fix it in advance. Therefore, in the present method, fixing of the inner tank side wall 31 on the annular portion 13 which takes about one month, for example, does not become a critical path, and the construction period can be shortened compared to the conventional method.

The inner tank bottom part construction step is performed in parallel with the above-mentioned inner tank side wall construction step, and ends at least before the third inner tank side wall construction step. By thus constructing the inner tank side wall 31 and the inner tank bottom 32 in parallel, the construction period can be shortened as compared with the conventional method.
When the inner tank 30 is completed, the outer tank roof 22 releases the connection with the inner tank roof 14 by a connecting material (not shown), and is installed at the upper end of the outer tank 2 assembled up to the uppermost stage. In addition, a roof stairway 24 is provided on the outer tank roof 22. Also, the pump barrel 25 is installed.
Thereafter, the suspended base 80 is removed and the jack-up device 19 is removed. Then, the tension work of the outer tank 2 is performed. Then, after closing the construction opening 8, water pressure is applied to carry out a pressure and air tightness test.

FIG. 10 is an explanatory view showing a sixth step of the construction method in the embodiment of the present invention.
Finally, as shown in FIG. 10, a cold insulating material 44 is disposed between the inner and outer tanks 15 between the inner tank 30 and the outer tank 2 and also between the inner tank roof 14 and the outer tank roof 22. 44 is arrange | positioned and cold insulation construction is performed, Then, painting construction, piping cold insulation construction are passed, and the LNG tank 50 is constructed | assembled.

  As described above, according to the present embodiment described above, the method of constructing the double shell LNG tank 50 having the inner tank constructing step of constructing the inner tank 30 inside the outer tank 2, the inner tank constructing step Has an inner tank bottom construction step of constructing the inner tank bottom 32 on which the inner tank bottom plate 41 is laid, and in the inner tank bottom construction step, the loading rack 90 is installed inside the outer tank 2. The inner tank bottom plate carrying-in step of carrying the inner tank bottom plate 41 into the outer tank 2 from the formed construction opening 8a via the carrying-in rack 90, and the longitudinal direction of the inner tank bottom plate 41 at least in the installation area 91 of the carrying-in rack 90 An inner tank bottom plate 41a1 to be laid after removal of the loading rack 90 by adopting a method of having an inner tank bottom plate laying step of laying an inner tank bottom plate 41a1 in a direction following the opening direction of the construction opening 8a. Reduce the number of sheets and lay the inner tank bottom plate 41 Work can be more efficient.

  As mentioned above, although the suitable embodiment of the present invention was described referring to drawings, the present invention is not limited to the above-mentioned embodiment. The shapes, combinations, and the like of the constituent members shown in the above-described embodiment are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

  For example, although the case where the present invention was applied to the LNG tank was illustrated in the above-mentioned embodiment, the present invention is applicable also to the tank which stores other low temperature liquids (for example, LPG etc.).

  Also, for example, the present invention can be applied not only to the method of constructing a tank using a jack-up device, but also to the method of constructing a tank using an air laying method.

Reference Signs List 2 outer tank 8a construction opening 9 inner tank side plate 9a first structure 9b second structure 10 portal frame 19 jack-up device 30 inner tank 31 inner tank side wall 32 inner tank bottom 32A inner tank bottom 41 inner tank bottom plate 41a Inner tank bottom plate 41a1 Inner tank bottom plate 41b Inner tank bottom plate 41b1 Inner tank bottom plate 50 LNG tank (tank)
90 Loading rack 91 installation area L1 construction opening reference line L2 bottom plate installation reference line O center α angle

Claims (4)

A method of constructing a double shell tank, comprising an inner tank construction step of constructing an inner tank inside an outer tank,
The inner tank constructing step has an inner tank bottom constructing step of constructing an inner tank bottom in which an inner tank bottom plate is laid,
The inner tank bottom construction step is
An inner tank bottom plate carrying-in step of installing a loading racket inside the outer tank and carrying the inner tank bottom plate inside the outer tank from the construction opening formed in the outer tank via the loading racket;
An inner tank bottom plate laying step of laying the inner tank bottom plate in a direction in which the longitudinal direction of the inner tank bottom plate follows the opening direction of the construction opening at least in the installation area of the carry-in racket. How to build a tank. The inner tank construction step includes an inner tank side wall construction step of constructing an inner tank side wall on which an inner tank side plate is assembled,
Said inner tank side wall construction process,
On the inner side of the outer tank, the lifting of the inner tank side plate by the jack-up device and the attachment of the next inner tank side plate to the lower side of the raised inner tank side plate are alternately repeated alternately. A first inner tank side wall construction step of assembling the first structure excluding the lower part;
A second inner tank side wall constructing step of assembling a second structure which is the lowermost stage of the inner tank side wall on an annular portion provided on a peripheral portion of the inner tank bottom;
And a third inner tank side wall construction step of joining the first structure and the second structure and assembling the inner tank side wall,
The tank according to claim 1, wherein the inner tank bottom portion constructing step is performed in parallel with the inner tank side wall constructing step and is completed before at least the third inner tank sidewall constructing step. How to build. In the inner tank bottom plate laying step,
A first inner tank bottom plate laying step of laying the inner tank bottom plate in a region other than the installation region of the loading rack;
A loading rack removal process for removing the loading rack after the first inner tank bottom plate laying process;
The second inner tank bottom plate laying step of laying the inner tank bottom plate in the area where the carry-in racket has been installed after the loading / removing rack removal step. How to build a tank.   The length in the longitudinal direction of the carry-in cradle is shorter than the length in the longitudinal direction of the inner tank bottom plate laid in the installation area of the carry-in cradle, according to any one of claims 1 to 3 How to build a tank.

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