JP6465488B2 - Construction method of cylindrical tank - Google Patents

Description

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

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

  Patent Document 1 discloses a technique for constructing a metal inner tank and a concrete outer tank at the same time in order to shorten the construction period of the cylindrical tank. Specifically, a jack stand is erected at the bottom of the outer tub, and the jack-up device is supported at a predetermined height (see FIG. 4B of Patent Document 1). And when performing the side wall construction of the outer tub, the inner tub roof and the outer tub roof are assembled on the bottom of the outer tub, and then the inner tub roof and the outer tub roof are raised by the jack-up device, By installing the inner tank side plates on the tank roof sequentially from the uppermost one to the lowermost one, the simultaneous construction of the metal inner tank and the concrete outer tank is realized.

Japanese Patent Laid-Open No. 7-62924

  By the way, the side wall of the outer tub is constructed as follows, for example. First, the bottom of the outer tub is constructed, and steel liner materials are sequentially stacked in layers on the bottom and fixed by welding. When the liner material has been assembled, the outer mold is then installed, and concrete is cast using the liner material as the inner mold to construct the sidewall of the outer tub. In this method, in order to prevent buckling due to wind load of an independent and self-supporting liner material, the thickness of the liner material has to be increased, and the amount of construction cannot be minimized. .

  Therefore, the inventors of the present invention devised a method of assembling the liner from the bottom of the outer tub in advance, placing concrete with the liner material as an inner mold following the assembly, and assembling the side walls of the outer tub. did. According to this method, the assembling of the liner material and the placing of the concrete are performed in parallel with a certain interval, and the liner material is supported by the concrete within a certain range, so that buckling due to wind load can be suppressed. In addition, by doing so, it becomes possible to minimize the amount of construction by minimizing the thickness of the liner material.

  However, also in this method, the liner material (uppermost stage) assembled prior to the concrete is not supported by the concrete, and becomes independent and independent. For this reason, it was necessary to weld, for example, a yoke material as a strong ring to the liner material. However, since this yoke material gets in the way of the cold insulation work between the inner and outer tubs, it must be finally removed from the liner material. Therefore, there is a problem that a great amount of work occurs in attaching and removing the yoke material.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for constructing a cylindrical tank that can easily maintain the shape of a liner material assembled prior to placing concrete.

  In order to solve the above problems, the present invention is a method of constructing a cylindrical tank having a metal inner tub and a concrete outer tub, and precedes a steel liner from the bottom of the outer tub. While assembling, following the assembly, placing the liner material as an inner formwork, placing concrete, and having an outer tank side wall building process for building the side wall of the outer tank, the outer tank side wall building process, A plurality of scaffolding units each provided with a beam member are hooked to a plurality of receiving beams installed on the inward plate surface of the liner material assembled in advance, and the scaffold unit hooked on the receiving beams A method of including a scaffold unit connecting step of connecting the beam members annularly along the inward plate surface of the liner material is adopted.

  Further, in the present invention, the scaffold unit is provided with the beam member up and down, and in the scaffold unit connecting step, the upper and lower sides of the beam member are connected annularly along the inward plate surface of the liner material, The method is adopted.

  In the present invention, a method is adopted in which the scaffold unit includes scaffolds on the upper and lower sides of the beam member.

  Moreover, in this invention, the method that the said beam member is H-section steel is employ | adopted.

  Further, in the present invention, on the inner side of the side wall of the outer tub, the raising of the inner tub side plate by the jack-up device and the welding of the next inner tub side plate to the lower side of the raised inner tub side plate are alternately performed. The method of having the inner tank side wall construction process which builds the side wall of the said inner tank repeatedly is employ | adopted.

According to the present invention, a plurality of scaffolding units including beam members are hooked on a plurality of receiving beams installed on an inward plate surface of a liner material assembled prior to placing concrete, and the beams of the scaffolding unit By connecting the members in an annular shape, an annular strong ring can be formed along the inward plate surface of the liner material. The annularly connected beam members maintain the shape of an independent and self-supporting liner material and function as a buckling prevention material (so-called stiffener) due to wind load. Furthermore, since the scaffold units are connected in the circumferential direction of the tank by connecting the beam members, and the scaffold can be formed over the entire circumference of the tank, the construction of the liner material is facilitated. Moreover, since the scaffold unit is hooked on the receiving beam of the liner material, the attachment and removal work of the scaffold unit is easy.
Therefore, in the present invention, the shape of the liner material assembled prior to the concrete placement can be easily maintained.

It is explanatory drawing which shows the 1st process of the construction method in embodiment of this invention. It is a side view which shows the installation state of the scaffold unit in embodiment of this invention. It is arrow A figure shown in FIG. FIG. 3 is an arrow B view shown in FIG. 2. It is explanatory drawing which shows the 2nd process of the construction method in embodiment of this invention. It is explanatory drawing which shows the 3rd process of the construction method in embodiment of this invention. It is explanatory drawing which shows the 4th process of the construction method in embodiment of this invention. It is explanatory drawing which shows the 5th process of the construction method in embodiment of this invention. It is explanatory drawing which shows the 6th process of the construction method in embodiment of this invention. It is a side view which shows the installation state of the scaffold unit in another embodiment of this invention.

  Hereinafter, the construction method of the cylindrical tank of the present invention will be described with reference to the drawings. In the following description, a ground type PC (prestressed concrete) double-shell storage tank for storing LNG is exemplified as the cylindrical tank.

FIG. 1 is an explanatory diagram showing a first step of the construction method according to the embodiment of the present invention.
As shown in FIG. 1, in this method, first, construction of a substantially disk-shaped foundation plate 1 made of concrete (the bottom of the outer tub) is performed. Next, the bottom liner 6 is laid on the foundation plate 1. Then, the roof pedestal 7 is assembled at the center of the base plate 1. Moreover, the PC wall 2 (side wall of the outer tub) is constructed at the outer peripheral edge of the base plate 1 (outer tub side wall construction step).

  The PC wall 2 is constructed by assembling the side liner 2a (steel liner material) in advance from the base plate 1 and driving concrete 2b following the assembly and using the side liner 2a as an inner mold. . The side liner 2a is, for example, a large steel plate having a length of 4.5 m, a width of 12 m, and a thickness of 8 mm. An outer scaffold 5 is installed on the outside of the side liner 2a, an outer mold (not shown) is assembled so as to face the side liner 2a, and concrete 2b is placed.

  The side liner 2a is joined by welding in the circumferential direction so as to be cylindrical as a whole. The next side liner 2a is welded to the upper side of the side liner 2a joined in a cylindrical shape, and similarly, the next side liner 2a is joined by welding in the circumferential direction so as to form a whole cylindrical shape. In addition, it is preferable to perform the welding of the side liners 2a by one-side welding from the inside of the tank. For example, it is preferable to perform butt welding with a backing using a backing metal. In this way, by making the welding of the side liners 2a one-sided welding from the inside of the tank, interference with the concrete 2b placing work on the outside of the tank can be avoided.

  Assembling of the side liner 2a and placing of the concrete 2b are performed alternately. That is, when the side liner 2a is assembled in advance, the concrete 2b is placed using the lower side liner 2a as the inner mold. For this reason, the assembling of the side liner 2a and the placing of the concrete 2b are parallel operations with a certain interval. Thereby, the protrusion part L of the side liner 2a of the height which is not placing concrete 2b can be restrained to a certain fixed range. For this reason, in designing the side liner 2a, it is only necessary to design a plate thickness that allows the side liner 2a to be independent and independent at the protruding portion L. The design can be optimized to minimize the amount of construction, and to reduce costs. Can do.

  By the way, there is no structure for positioning (particularly positioning in the tank radial direction) around the side liner 2a (uppermost stage) assembled in advance. In the protruding portion L, the side liner 2a alone receives wind load. Moreover, in order to perform the welding operation of the side liner 2a, an inner scaffold is also necessary. Therefore, in this method, in the construction of the PC wall 2, a scaffold unit 100 that also serves as a shape maintenance of the side liner 2a, a welding work scaffold for the side liner 2a, and a buckling prevention material (so-called stiffener) due to wind load is installed.

FIG. 2 is a side view showing an installation state of the scaffold unit 100 in the embodiment of the present invention. FIG. 3 is an arrow A view shown in FIG. 4 is an arrow B view shown in FIG.
As shown in FIG. 2, a plurality of receiving beams 101 are installed on the side liner 2a. The receiving beam 101 is a steel material assembled in an L shape that extends in the horizontal direction from the side liner 2a and then rises in the vertical direction. This receiving beam 101 is fixed to the inward plate surface 102 facing the inside of the tank of the side liner 2a by welding.

  As shown in FIG. 3, a plurality of receiving beams 101 are arranged at intervals in the longitudinal direction of the side liner 2a. A plurality of the receiving beams 101 are arranged so as to be hooked at three positions per one scaffold unit 100 in the longitudinal direction. The receiving beams 101 of this embodiment are arranged in two upper and lower rows, and can be hooked at a total of six locations per one scaffold unit 100. The receiving beam 101 is preferably welded to the side liner 2a in advance on the ground before assembling the side liner 2a.

  As shown in FIG. 2, the scaffold unit 100 includes a beam member 110 that can be hooked on the receiving beam 101, and a scaffold 120 that is integrally fixed to the beam member 110. The beam member 110 extends along the inward plate surface 102 in the longitudinal direction of the side liner 2a (the depth direction of the paper surface shown in FIG. 2). The beam member 110 becomes a strong ring of the side liner 2a by the connection described later, and maintains the shape of the side liner 2a. In the present embodiment, for example, an H-shaped steel having a cross-sectional dimension of 200 mm long × 200 mm wide can be suitably used as the beam member 110.

  The scaffold unit 100 includes beam members 110 at the top and bottom. As shown in FIG. 3, the upper and lower beam members 110 are hooked on the receiving beam 101 at three positions. The scaffold unit 100 includes a scaffold 120 on each of the upper and lower sides of the beam member 110. The scaffold 120 is supported by a plurality of projecting members 121 (see FIG. 4) welded to the beam member 110, a cross member 122 fixed to the ends of the plurality of projecting members 121, and the projecting member 121 and the cross member 122. Scaffolding plate 123.

  An oblique member 124 is connected to the bottom of the scaffold 120 as shown in FIG. One end of the slanting member 124 is fixed to the overhanging member 121 with a bolt or the like, and the other end is in contact with the inward plate surface 102 of the side liner 2a. The other end of the diagonal member 124 that supports the bottom of the upper scaffold 120 is fixed to a vertical member 125 that connects the upper and lower beam members 110 with a bolt or the like. The other end of the diagonal member 124 that supports the bottom of the lower upper scaffolding 120 is fixed to a vertical member 126 that extends downward from the lower beam member 110 with a bolt or the like.

In addition, the scaffold unit 100 includes a vertical member 126 that connects the upper and lower scaffolds 120. As shown in FIG. 3, a cross member 127 serving as a handrail is fixed to the vertical member 126.
As shown in FIG. 3, a plurality of scaffold units 100 having the above configuration are attached to the side liner 2a. Specifically, a plurality of scaffold units 100 are attached by hooking the beam members 110 of the scaffold unit 100 to the receiving beam 101 as shown in FIG. The beam member 110 and the receiving beam 101 are preferably connected with a bolt or the like in order to maintain the hooked state. The scaffold unit 100 may be attached to the side liner 2a in advance on the ground.

  Next, as shown in FIG. 3, the beam members 110 of the scaffold unit 100 hooked to the receiving beam 101 are connected in an annular shape along the inward plate surface 102 of the side liner 2a (scaffold unit connecting step). . As shown in FIG. 4, the beam members 110 are preferably connected to each other using a connection plate 130 such as a face plate to which a plurality of bolts can be fastened. Moreover, as shown in FIG. 3, it is preferable that the connection plate 130 connects the upper and lower sides of the flange of the beam member 110 (H-section steel). The beam member 110 is connected by the connection plate 130 to form a strong ring having an annular shape (in detail, a polygonal annular shape close to a circle) that goes around the tank.

  Thus, according to this method, the scaffold unit 100 including the beam members 110 is attached to the plurality of receiving beams 101 installed on the inward plate surface 102 of the side liner 2a assembled prior to the placement of the concrete 2b. By hooking a plurality of beams and connecting the beam members 110 of the scaffold unit 100 in an annular shape, an annular strong ring can be formed along the inward plate surface 102 of the side liner 2a. As shown in FIG. 2, the beam members 110 connected in an annular shape maintain the shape of the independent side liner 2a and function as a buckling prevention material (so-called stiffener) due to wind load. Furthermore, since the scaffold unit 100 is connected in the circumferential direction of the tank by connecting the beam member 110 and can form a scaffold over the entire circumference of the tank, the side liner 2a can be easily constructed (welded or the like).

  Further, as shown in FIG. 2, the scaffold unit 100 is hooked on the receiving beam 101 of the side liner 2 a, so that the attachment and removal work of the scaffold unit 100 is easy. For example, if the bolting that maintains the hooked state of the beam member 110 and the receiving beam 101 is released, the scaffold unit 100 can be easily removed (lifted) from the side liner 2a with a crane or the like. Further, the receiving beam 101 is dotted and welded to the side liner 2a, and since each piece is small in a piece shape, it can be easily removed if it becomes an obstacle during the cold insulation work described later. . Thus, according to this method, the shape of the side liner 2a assembled prior to the placement of the concrete 2b can be easily maintained.

  Moreover, the scaffold unit 100 is provided with the beam member 110 up and down, and at the scaffold unit coupling step, the beam member 110 is coupled in an annular shape along the inward plate surface 102 of the side liner 2a. According to this method, since the independent and independent side liner 2a is supported by the two upper and lower strong rings, the shape of the side liner 2a can be maintained with higher accuracy. For example, the side liner 2a can be taken in and out with reference to the beam members 110 connected in an annular shape, and the radial position of the side liner 2a can be adjusted with high accuracy. Further, according to this method, since the size of the cross section per beam member 110 can be reduced rather than ensuring the rigidity with one beam member 110, the assembly operation of the scaffold unit 100 and the like are facilitated.

The scaffold unit 100 includes a scaffold 120 on each of the upper and lower sides of the beam member 110. According to this configuration, operations such as welding of adjacent side liners 2a (vertical seam welding) and inspection related to the welding are facilitated.
Moreover, since the beam member 110 is H-shaped steel, the manufacturing cost of the scaffold unit 100 can be reduced as compared with the case where a custom steel material is used.

FIG. 5 is an explanatory diagram showing a second step of the construction method according to the embodiment of the present invention.
As shown in FIG. 5, in this method, the PC wall 2 is constructed while attaching the scaffold unit 100 to the side liner 2a as described above. In addition, an inner tank anchor strap 4 is installed on the base plate 1 inside the PC wall 2. Moreover, the construction port 8 for taking in the inner tank side plate 9 one by one in the base end part of the PC wall 2 is formed. A plurality of gate-type mounts 10 for assembling the inner tank side plate are installed along the inside of the base end of the PC wall 2. The gate-type gantry 10 is installed so that a cylindrical inner tank formed by combining a plurality of inner tank side plates 9 straddles the annular area X, which is an area to be finally lowered on the base plate 1.

  Next, the inner tank side plate 9 is placed on the portal frame 10, the adjacent inner tank side plates 9 are welded together, and are joined together in the circumferential direction so as to form a cylindrical shape as a whole. Further, the knuckle plate 11 is assembled to the upper end portion of the inner tank side plate 9. In addition, the structural member 12 of the annular portion 13 (see FIG. 6) such as a pearlite concrete block or a structural lightweight concrete block is temporarily placed in the annular region X under the portal frame 10. Further, the inner tank roof 14 is assembled on the roof mount 7. Further, the knuckle plate 11 is assembled to the outer peripheral edge portion of the inner tank roof 14.

  Next, between the inner and outer tanks 15 (between the PC wall 2 and the inner tank side plate 9) above the base plate 1, the suspension jack frame 16 (on the PC wall 2 above the knuckle plate 11 is placed. Install multiple suspension points in the circumferential direction of the tank. The suspension side jack mount 16 is provided so as to protrude substantially horizontally from the PC wall 2 having a predetermined height toward the inside of the tank. The suspension-side jack mount 16 is fastened and fixed to, for example, an anchor plate embedded in the PC wall 2 in a strong and detachable manner.

  The knuckle plate 11 is provided with a plurality of knuckle reinforcing members 17 facing the plurality of suspension side jack mounts 16. The knuckle reinforcement 17 projects from the knuckle plate 11 toward the inner / outer tank 15. Further, the knuckle reinforcing member 17 serves as a suspended base. A jack-up device 18 is installed between the suspension-side jack mount 16 and the knuckle reinforcing member 17. The jack-up device 18 is a center hole jack. The device main body is installed on the suspension-side jack mount 16 and the lower end of the jack-up rod 19 is attached to the knuckle reinforcement member 17.

  When the jackup device 18 is thus installed, the roof mount 7 is removed, and the knuckle plate 11 is lifted by the jackup device 18 to raise the inner tank side plate 9. When the jack-up device 18 is raised by one stroke of the jack-up rod 19 (corresponding to the vertical width of the inner tank side plate 9 alone in this embodiment), the jack is raised to the space formed at the lower part of the inner tank side plate 9. The next inner tank side plate 9 is carried in.

FIG. 6 is an explanatory diagram showing a third step of the construction method according to the embodiment of the present invention.
When the next inner tank side plate 9 is joined in the circumferential direction of the tank, the upper end thereof and the lower end of the raised inner tank side plate 9 are welded. Next, the inner tank side plate 9 integrated by this welding is jacked up by the jack-up device 18, and the next inner tank side plate 9 is carried into the space formed below the inner tank side plate 9 by the jack-up. Thus, the raising of the inner tank side plate 9 by the jack-up device 18 and the welding of the next inner tank side plate 9 to the lower side of the raised inner tank side plate 9 are alternately repeated (inner tank side wall construction step). In this method, the inner tank side plate 9 is attached in order from the uppermost one, and the first structure 9a excluding the lowermost stage of the inner tank side plate 9 is assembled.

  In addition, during this process, the cold insulation work of the annular portion 13 is performed in parallel under the portal frame 10. When the cold insulation work of the annular portion 13 is completed, as shown in FIG. 6, the leg portion 10 a arranged inside the tank with respect to the annular portion 13 is replaced on the annular portion 13. By such replacement, there is no interference on the inside of the tank with respect to the annular portion 13, so that the cold insulation work at the center portion on the base plate 1 can be performed. In the cold insulation work in the center, the foam glass 40 is placed on the bottom cooling resistance reducing material 39. Then, a pearlite concrete block (not shown) and an inner tank bottom plate (not shown) are laid on top of each other in this order.

FIG. 7 is an explanatory diagram showing a fourth step of the construction method according to the embodiment of the present invention.
In this method, as shown in FIG. 7, 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, when the lowermost stage of the inner tank side plate 9 is placed 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 base plate 1 is attached.

  Further, as shown in FIG. 7, the outer tank roof 22 is assembled on the inner tank roof 14. The outer tank roof 22 is connected to the inner tank roof 14 by a connecting material (not shown), and is assembled integrally with the inner tank roof 14. Further, an elevating staircase 23 is provided outside the PC wall 2. Further, the pump barrel 25 is carried inside the PC wall 2.

FIG. 8 is an explanatory diagram showing a fifth step of the construction method according to the embodiment of the present invention.
Next, in this method, as shown in FIG. 8, the first structure 9a is jacked down, the lower end portion of the first structure 9a is lowered to the upper end portion of the second structure 9b, and the first structure 9a is lowered. The structure 9a and the second structure 9b are welded, and the inner tank 30 is assembled. In this method, the assembly of the lowermost stage of the inner tank 30 is separated from the assembly of the inner tank 30 by the jack-up device 18, and the second structure 9 b that is the lowermost stage of the inner tank 30 is fixed on the annular portion 13. Is carried forward (see FIG. 7). Therefore, in this method, for example, fixing the inner tank 30 on the annular portion 13 which takes about one month does not become a critical path, and the construction period can be shortened compared to the conventional method.

When the inner tub 30 is completed, the outer tub roof 22 is disconnected from the inner tub roof 14 by a connecting material (not shown) and installed on the upper end of the PC wall 2 assembled to the top. A roof staircase 24 is provided on the outer tank roof 22. A pump barrel 25 is also installed.
Thereafter, the knuckle reinforcement member 17 is cut off and the jackup device 18 is removed. After that, tension work on the PC wall 2 is performed. Then, after the construction port 8 is closed, it is filled with water and a pressure and airtight test is performed.

FIG. 9 is an explanatory diagram showing a sixth step of the construction method according to the embodiment of the present invention.
Finally, as shown in FIG. 9, the cold insulation material 44 is arranged between the inner and outer tanks 15 and the cold insulation material 44 is arranged between the inner tank roof 14 and the outer tank roof 22 to perform the cold insulation work. The cylindrical tank 50 is constructed through painting work and pipe cooling work.

  Therefore, according to the above-described embodiment, it is a construction method of the cylindrical tank 50 having the metal inner tank and the concrete outer tank, and the steel side liner 2a is preceded from the base plate 1. While assembling, there is an outer tank side wall construction process in which concrete 2b is placed using the side liner 2a as an inner mold to construct the PC wall 2, and the outer tank side wall construction process is assembled in advance. A plurality of scaffold units 100 including beam members 110 are hooked to a plurality of receiving beams 101 installed on the inward plate surface 102 of the side liner 2a, and the beam members of the scaffold unit 100 hooked to the receiving beams 101 By using a method of including a scaffold unit connecting step of connecting 110 to each other in a ring shape along the inward plate surface 102 of the side liner 2a, the assembly is performed prior to placing the concrete 2b. The shape of the raised side liner 2a can be easily maintained.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various 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 gist of the present invention.

  For example, as in another embodiment shown in FIG. 10, the direction of the beam member 110A (H-shaped steel) may be rotated by 90 ° with respect to the above-described embodiment. If the web connecting the flanges of the H-shaped steel is oriented perpendicularly (horizontally) to the inward plate surface 102, it becomes strong against the load received from the inward plate surface 102 of the side liner 2a. Since the beam member 110A in this direction is difficult to be connected to the receiving beam 101 with a bolt or the like, it is preferable to drive the wedge member 140 into the gap and fix it as shown in FIG.

1 Basic version (bottom of outer tank)
2 PC wall (side wall of outer tank)
2a Side liner (steel liner)
2b Concrete 50 Cylindrical tank 100 Scaffolding unit 101 Receiving beam 102 Inward plate surface 110 Beam member 120 Scaffolding

Claims (5)

A construction method of a cylindrical tank having a metal inner tank and a concrete outer tank,
Constructing an outer tank side wall in which a steel liner material is assembled from the bottom of the outer tank in advance, and concrete is placed using the liner material as an inner mold following the assembly, thereby constructing the outer tank side wall. Having a process,
In the outer tub side wall construction step, a plurality of scaffolding units including beam members are hooked on a plurality of receiving beams installed on the inward plate surface of the liner material assembled in advance, and the receiving beams A method for constructing a cylindrical tank, comprising: a scaffold unit coupling step for annularly coupling the beam members of the suspended scaffold unit along an inward plate surface of the liner material. The scaffold unit is provided with the beam member up and down,
2. The cylindrical tank construction method according to claim 1, wherein, in the scaffold unit coupling step, the upper and lower portions of the beam member are coupled in an annular shape along the inward plate surface of the liner material.   The method for constructing a cylindrical tank according to claim 2, wherein the scaffold unit includes a scaffold on each of the upper and lower sides of the beam member.   The said beam member is H-section steel, The construction method of the cylindrical tank as described in any one of Claims 1-3 characterized by the above-mentioned.   Inside the side wall of the outer tub, the inner tub side plate is lifted by a jack-up device and the welding of the next inner tub side plate to the lower side of the raised inner tub side plate is alternately repeated. 5. The method for constructing a cylindrical tank according to claim 1, further comprising an inner tank side wall constructing step for constructing the tank.

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