JP6371182B2 - Tank construction method and tank - Google Patents

Description

  The present invention relates to a tank construction method and a tank.

  A PC (prestressed concrete) tank is a facility for storing liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas). FIG. 9 shows an example of an LNG tank 100 that stores LNG as a PC tank. The LNG tank 100 of FIG. 9 is provided with a liquid breakwater 2 on a bottom slab 5 supported by a pile 4 in the ground 7 and an inner tank 3a and an outer tank 3b made of steel plates or the like inside. The roof portion of the outer tub 3b is made of steel or reinforced concrete, and the side portion has a shape in which a liner plate (thin iron plate) is attached to the liquid barrier 2. LNG is stored in the inner tank 3a, and a heat insulating material is disposed between the inner tank 3a and the outer tank 3b to perform cold insulation.

  The breakwater 2 is a side wall made of prestressed concrete and is usually cylindrical. The breakwater 2 is provided to prevent leakage of LNG to the outside when the inner tank 3a is damaged. The breakwater 2 is required to have a structure capable of withstanding the hydraulic pressure of LNG, and prestress due to a tension material (not shown) in the circumferential direction and the vertical direction is introduced for this purpose. Further, in order to improve the proof strength against the hydraulic pressure, the bottom of the liquid breakwater 2 is generally fixed to the bottom plate 5 and integrated.

  As a construction method of the breakwater 2, an example is known in which circumferential prestress is introduced into the breakwater 2 in a state where the breakwater 2 is movable with respect to the bottom slab 5 (see, for example, Patent Document 1). ). In this case, since the breakwater 2 moves inward when the prestress in the circumferential direction is introduced, the breakwater 2 is then fixed to the bottom plate 5 and the prestress in the vertical direction is introduced. Thereby, it is advantageous in that the circumferential prestress can be effectively introduced into the liquid breakwater 2 without being restricted by the bottom plate 5 and the amount of tension material can be reduced.

  In this operation, for example, as shown in FIG. 10A, the bottom plate 5 is provided with the slide portion 21, and the liquid barrier 2 is constructed thereon. The slide portion 21 enables the liquid breakwater 2 to be slid inward when prestressing in the circumferential direction is introduced, and is a removable formwork such as laid sand.

  A sheath tube (not shown) for inserting a tension material and a reinforcing steel bar (not shown) are embedded in the breakwater 2 and the bottom plate 5. Inside the breakwater 2, sheath tubes and reinforcing bars are embedded in the circumferential direction and the vertical direction of the breakwater 2. A fixing body 170 for fixing the tendon material is also embedded in the bottom plate 5.

  The breakwater 2 is constructed in a state in which an opening 20 for construction is provided. The opening 20 is used for carrying in materials for constructing an inner tank such as a side wall steel plate, carrying in other small materials and equipment for construction, and entering and leaving workers. Thereby, the construction of the inner tub 3a and the like can be efficiently performed in parallel with the construction of the breakwater 2.

  In the example of the figure, the lower end portion of the vertical PC steel material 17b, which is a tension material, is attached to the fixing body 170, and the portion other than the upper portion of the opening 20 in the liquid barrier 2 is continuous from the lower end portion. The vertical PC steel material 17 b is passed to the top of the liquid breakwater 2 or the lower edge of the opening 20. Above the opening 20, the vertical PC steel material 17 b is passed from the upper edge of the opening 20 to the top of the liquid barrier 2. The vertical PC steel material 17b is disposed through the sheath tube.

  The opening 20 is closed at the stage when the construction of the inner tub 3a is almost completed, and then the tension material is tensioned. The closing of the opening 20 and the tension of the tendon are performed by the following procedure, for example. That is, a sheath tube and a reinforcing bar (not shown) in the circumferential direction and the vertical direction are arranged in the opening 20 and connected to the sheath tube and the reinforcing bar in the liquid barrier 2 respectively. Further, another vertical PC steel material is placed in the opening 20 through the sheath tube, connected to the vertical PC steel material 17b above and below the opening 20, and these are continuously connected to a single vertical PC steel material 17b. To do. Then, concrete 22 is placed in the opening 20 as shown in FIG.

  Thereafter, as shown in FIG. 11 (a), the circumferential PC steel material 17a is passed through the sheath tube and provided in the liquid breakwater 2, and is tensioned as shown by the arrow a to fix both ends to a pilaster (not shown). The circumferential prestress is introduced into the breakwater 2. The pilaster is a protruding portion of the breakwater 2 provided for fixing the PC steel material.

  When the circumferential prestress is introduced, the entire cylindrical breakwater 2 moves inward, and thereafter, the bottom of the breakwater 2 is filled with a filler 23 such as grout as shown in FIG. 11 (b). Secure to. Hereinafter, the vertical PC steel material 17b is tensioned as indicated by an arrow b, and a vertical prestress is introduced into the breakwater 2. At this time, the upper end of the vertical PC steel material 17 b is fixed to the top of the liquid barrier 2 by the fixing body 171.

  In this example, the breakwater 2 is slidable with respect to the bottom slab 5, but the breakwater 2 may be pin-coupled to the bottom slab 5. Further, in Patent Document 2, as described above, another tension material is connected to the tension material provided in the side wall of the tank at the opening of the side wall, and after closing the opening with concrete, the side wall is caused by tension of the tension material. Describes the introduction of prestress. Patent Document 3 describes that prestress due to tension of a tension material is introduced into the side wall in a state where a small-sized opening is left at a position avoiding the tension material on the side wall of the tank.

JP 2009-203787 JP 63-31634 A Patent No. 4964346

  In the above-described conventional method, after the construction of the inner tub 3a is finished, the opening 20 is closed, a tension material is placed on the liquid breakwater 2 to perform circumferential tension, and the bottom of the liquid breakwater 2 is removed. The flow of fixing and tensioning in the vertical direction became critical, and the work period after the construction of the inner tank 3a and the like was long, and the entire process tended to be long.

  On the other hand, in the method of Patent Document 3, the prestress of the sidewall can be introduced at an early stage while leaving the opening. However, since the opening is positioned away from the tendon, it must be small. For this reason, for example, the work of carrying the side wall steel plate of the inner tub 3a into the tank cannot be performed, and there is a limit to the type of work that can be performed using the opening, and a more efficient method is required.

  An object of the present invention is to provide a tank construction method and the like that are highly efficient and can shorten the construction period.

1st invention for solving the subject mentioned above is the construction method of the tank which has the side wall by prestressed concrete, Comprising: The said side wall is constructed in the state which left the opening part for construction, The said opening part of the said side wall At least a part of the tendon comprising: a step (a) of introducing a prestress into the side wall by tensioning a tendon passed through a portion excluding the step; and a step (b) of closing the opening. Has one end at the edge of the opening, and when the prestress by the tension material is introduced, the one end is fixed at the edge of the opening. In the step (b), concrete is applied to the opening. The tank construction method is characterized in that the concrete is placed and prestress due to the tension of the additional tension material is introduced into the concrete, and the additional tension material includes a vertical tension material .

  After constructing the inner tank of the tank, it is desirable to close the opening in the step (b).

One end of the previous SL additional tendons is connected to the one end of the tension member having one end at the edge of the opening, the other end of said additional tendon, upon introduction of the pre-stress by the additional tendons, the opening It is desirable to be fixed to the side wall in the vicinity of the portion. Alternatively, it is also desirable that both ends of the additional tendon are fixed to the side wall in the vicinity of the opening when prestress is introduced by the additional tendon.

  Further, when prestress is introduced in the step (a), the circumferential tension material of the side wall is tensioned to introduce circumferential prestress to the side wall, and the side wall moves inward, and then the side wall Is fixed to the bottom plate, and then the vertical tension material is tensioned to introduce vertical prestress to the side wall.

2nd invention is a tank which has a side wall by the prestressed concrete, Comprising: The prestress is introduce | transduced into the said side wall by tension | tensile_strength of the tension material passed through the part except the predetermined area | region of the said side wall, At least one part of the said tension material Has one end at the edge of the predetermined area, the one end is fixed at the edge of the predetermined area, an additional tension material is provided in the predetermined area, and the tension of the additional tension material is provided in the predetermined area. Prestress is introduced, and the additional tendon includes a vertical tendon .

  According to the present invention, the prestress of the side wall can be introduced at an early stage while leaving the opening, and the construction of the side wall can be completed if the opening is closed after the construction of the inner tub is completed. In this procedure, the work after the construction of the inner tank is completed, and the entire process can be shortened without taking time.

  In addition, in the present invention, the tension material is fixed to the opening portion instead of providing the opening portion avoiding the tension material. Accordingly, a relatively large opening can be left on the side wall, and the side wall steel plate of the inner tank can be carried in through the opening, and various types of work can be performed using the opening. Moreover, since a tension material can be arrange | positioned also to the side of the opening part, upper direction, and the downward direction, the prestress of a side wall can be introduce | transduced uniformly and a side wall can be constructed | assembled suitably. Thereby, in the method of the present invention, a tank can be constructed efficiently and suitably, and the construction period can be shortened.

  Moreover, in this invention, reinforcement | strengthening of the said area | region is suitably performed by introduce | transducing prestress into the area | region of the opening part obstruct | occluded with concrete using an additional tension material. At this time, connect one end of the additional tendon to the tendon and fix the other end in the vicinity of the opening, or fix both ends of the additional tendon in the vicinity of the opening so that the additional tendon is appropriately Can be placed.

  Further, in the present invention, the side wall is arranged so as to be movable with respect to the bottom plate, and after the side wall is moved inward by introduction of circumferential prestress, the side wall is fixed to the bottom plate and vertical prestress is introduced. Accordingly, circumferential prestress can be effectively introduced into the side wall in a state where there is no restraint by the bottom plate, and the tank is fixed to the bottom plate at the time of completion, and a tank excellent in resistance to hydraulic pressure can be constructed.

  According to the present invention, it is possible to provide a tank construction method or the like that has high efficiency and can shorten the construction period.

Diagram showing how to build a tank Diagram showing how to build a tank Diagram showing how to build a tank Diagram showing how to build a tank Diagram showing how to build a tank Diagram showing how to build a tank The figure which shows arrangement of additional PC steel 19a The figure which shows the steel material 25 for reinforcement Diagram showing LNG tank 100 Diagram showing how to build a tank Diagram showing how to build a tank

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

  1-6 is a figure which shows the construction method of the tank which concerns on embodiment of this invention. In the present embodiment, an example of constructing the liquid breakwater 2 (side wall) of the LNG tank 100 described with reference to FIG. 9 will be described.

  As shown in FIG. 1 (a), in this embodiment, as in the example of FIG. 10 (a), the bottom plate 5 is provided with a slide portion 21, and the liquid barrier 2 is constructed thereon. Here, the concrete of the breakwater 2 is divided into several lots with a height of about 3.5-4.0m and placed in order from the bottom, and the breakwater 2 is constructed for the entire height.

  Similarly to the above, the slide portion 21 enables the breakwater 2 to be slid inward in the radial direction (center direction) when introducing a prestress in the circumferential direction, which will be described later. Can be used. However, it is not limited to this.

  In the breakwater 2 and the bottom slab 5, the same sheath tube and rebar as described above are embedded. The fixing body 170 described above is also embedded in the bottom plate 5. In addition, illustration of a sheath tube and a reinforcing bar is abbreviate | omitted in Fig.1 (a). The same applies to the other figures.

  The breakwater 2 is constructed with the opening 20 for construction provided in the lower part. The opening 20 is formed above the bottom plate 5 by a predetermined height. For example, the opening 20 is formed at the position of a few lots of concrete from the bottom, and the lower end of the opening 20 is positioned above the bottom plate 5 by the height of the concrete of one lot (for example, about 4.0 m). . FIG. 1B is a view showing a horizontal section of the opening 20. The same applies to FIGS. 2B, 5B, 6B, and 7 described later.

  A vertical direction PC steel material 17b (hereinafter referred to as a PC steel material 17b) is passed through the portion of the breakwater 2 excluding the opening 20 as described above. A plurality of PC steel materials 17b are provided at intervals in the circumferential direction of the liquid barrier 2 and arranged over the entire circumference of the liquid barrier 2. The PC steel material 17b is passed through the sheath tube in the vertical direction.

  As shown in FIG. 1A, at least a part of the PC steel material 17 b (the PC steel material 17 b above and below the opening 20) has one end at the edge of the opening 20. Further, the lower end portion of the PC steel material 17 b is attached to the fixing body 170 in the bottom plate 5 except for the PC steel material 17 b above the opening 20.

  In the present embodiment, the lower end portion of the PC steel material 17b is attached to the fixing body 170 in advance, and then the liquid breakwater 2 is constructed. For example, the bottom plate 5 is constructed in a state in which the fixing body 170 and the lower end portion of the PC steel material 17b attached to the fixing body 170 are embedded, and the remaining portion of the PC steel material 17b is temporarily placed. Then, prior to the construction of the breakwater 2, the remaining portion of the PC steel material 17b is moved to a predetermined position, and concrete is placed in a state where it is installed in the vertical direction.

  In addition, in the upper part of the opening 20, the PC steel material 17b is passed from the upper edge of the opening 20 to the top of the breakwater 2. The PC steel 17b is formed after, for example, building the breakwater 2, It can be arranged through a sheath tube in the breakwater 2.

  As shown in FIG. 1B, a fixing protrusion 2 a is provided on the liquid barrier 2 near the right side of the opening 20. The fixing protrusion 2 a protrudes outward from the liquid barrier 2. The fixing protrusion 2a is used for fixing an additional PC steel material to be described later. In the present embodiment, a similar fixing protrusion 2 a is also provided near the lower side of the opening 20.

  After constructing the breakwater 2 in this way, the circumferential PC steel material (tensile material) is placed through the portion other than the opening 20 of the breakwater 2 and the circumferential PC steel material is tensioned to the breakwater 2 in the circumferential direction. Introduce pre-stress. 2A and 2B are diagrams showing this state.

  Here, a plurality of circumferential PC steel materials 17a (hereinafter referred to as PC steel materials 17a) are provided at intervals in the vertical direction, and are arranged over the entire height of the liquid barrier 2. The PC steel material 17a is passed through the circumferential sheath tube. As shown in FIGS. 2A and 2B, at least a part of the PC steel material 17 a (the PC steel material 17 a on the side of the opening 20) has one end at the edge of the opening 20.

  Each PC steel material 17a is tensioned as indicated by arrows A1 and A2 in FIG. 2A, and circumferential prestress is introduced into the liquid barrier 2 from the fixed end. The PC steel material 17a is tensioned by, for example, double drawing, but may be single drawing.

  At this time, one end of the part of the PC steel material 17 a is fixed to the edge of the opening 20 using the fixing body 172. For example, the other end is fixed to the pilaster of the breakwater 2. The other PC steel material 17a is fixed to, for example, pilasters at both ends.

  When the circumferential prestress is thus introduced, the entire cylindrical breakwater 2 moves toward the inner side (center direction) in the radial direction of the breakwater 2 as shown by the arrow in FIG. The amount of movement is uniform over the entire circumference of the breakwater 2 and is, for example, about 10-30 mm. After the movement of the breakwater 2, the slide portion 21 is removed, and as shown in FIG. 3B, the bottom of the breakwater 2 is rigidly fixed to the bottom slab 5 with a filler 23 such as grout.

  Thereafter, the PC steel material 17b in the vertical direction is tensioned and the prestress in the vertical direction is introduced into the liquid breakwater 2. FIG. 4 is a diagram showing this state.

  Each PC steel material 17b is tensioned as shown by arrows B1 and B2 in FIG. 4, and vertical prestress is introduced into the liquid breakwater 2 from the fixed end. The PC steel material 17b is tensioned by pulling, for example, by pulling the upper part, but the PC steel material 17b above the opening 20 may be tensioned by double pulling.

  At this time, the one end of the PC steel material 17 b having one end at the edge of the opening 20 is fixed to the edge of the opening 20 using the fixing body 172. The other end is fixed to the top of the breakwater 2 by the fixing body 171 (in the case of the PC steel material 17b above the opening 20) or fixed by the fixing body 170 in the bottom plate 5 (below the opening 20). PC steel material 17b).

  The other PC steel material 17 b is fixed at one end to the top of the breakwater 2 by the fixing body 171. The other end is fixed in the bottom plate 5 by the fixing body 170.

  Thus, in this embodiment, since the liquid breakwater 2 is constructed in a state where the opening 20 is provided, the inner tank 3a is constructed using the opening 20 in parallel with the construction of the liquid breakwater 2. Etc. can be performed. In addition, prestress can be introduced into the breakwater 2 early by the PC steel materials 17a and 17b with the opening 20 left.

  Furthermore, rather than avoiding the PC steel materials 17a and 17b, the openings 20 are not provided, but the PC steel materials 17a and 17b are fixed in the openings 20, so that a relatively large opening 20 can be left in the liquid barrier 2. Therefore, it is possible to efficiently construct the inner tub 3a by using the opening 20 for carrying in materials for constructing the inner tub such as side wall steel plates, carrying in other small materials and equipment for construction, and entering and leaving the workers.

  In the present embodiment, after the construction of the inner tank 3a is completed, the opening 20 is closed. When closing the opening 20, a sheath tube and a reinforcing bar (not shown) in the circumferential direction and the vertical direction are arranged in the opening 20. These sheath tubes and reinforcing bars are connected to the sheath tubes and reinforcing bars in the liquid barrier 2.

  Further, as shown in FIGS. 5 (a) and 5 (b), as additional tension members, circumferential direction additional PC steel material 19a (hereinafter referred to as additional PC steel material 19a) and vertical direction additional PC steel material 19b (hereinafter referred to as additional PC steel material 19b). Is disposed in the opening 20. The additional PC steel materials 19 a and 19 b are passed through a sheath tube (not shown) of the opening 20. However, when an unbonded cable is used for the additional PC steel materials 19a and 19b, the above-described sheath tube can be omitted.

  As described above, at least some of the PC steel materials 17a and 17b have one end at the edge of the opening 20, and one end of the additional PC steel materials 19a and 19b is connected to the one end using a connecting jig 191 such as a coupler. Connected. In the illustrated example, one end of the additional PC steel material 19a is connected to one end of the PC steel material 17a at the left edge portion of the opening 20, and one end of the additional PC steel material 19b is connected to the PC steel material 17b at the upper edge portion of the opening portion 20. Connected to one end.

  As shown in FIG. 5B, the other end of the additional PC steel material 19 a is located at the position of the fixing protrusion 2 a in the vicinity of the right side of the opening 20. Similarly, the other end of the additional PC steel material 19b is at the position of the fixing protrusion 2a near the lower side of the opening 20. In the liquid breakwater 2, a sheath tube (not shown) extending from the opening 20 to the position of the fixing protrusion 2a is embedded in advance so as to pass the other ends of the additional PC steel materials 19a and 19b.

  After the additional PC steel materials 19a and 19b are arranged in the opening 20 in this way, concrete 22 is placed in the opening 20 as shown in FIGS. 6A and 6B, and the additional PC steel materials 19a and 19b are tensioned. Then, prestress is introduced into the concrete 22 in the region of the opening 20 (predetermined region).

  Here, after the concrete 22 is hardened, the additional PC steel materials 19a and 19b are tensioned as shown by arrows C and D in FIG. 6A, and the other end is fixed at the position of the fixing protrusion 2a. Prestress in the circumferential direction and vertical direction of the liquid bank 2 is introduced. The additional PC steel materials 19a and 19b are fixed using a fixing body 192.

  Thus, the opening 20 of the breakwater 2 is closed. By performing other necessary work, the LNG tank 100 shown in FIG. 9 is constructed.

  As described above, according to this embodiment, the prestress of the breakwater 2 can be introduced at an early stage with the opening 20 left, and after the construction of the inner tank 3a is finished, the opening 20 is If closed, construction of the breakwater 2 can be completed. In this procedure, the work after the construction of the inner tank 3a does not take time, and the entire process can be shortened.

  In addition, in this embodiment, the PC steel materials 17a and 17b are fixed to the opening 20 instead of providing the openings 20 avoiding the PC steel materials 17a and 17b. Accordingly, a relatively large opening 20 can be left in the breakwater 2, and the side wall steel plate of the inner tub 3 a can be carried in through the opening 20, and various types of work are performed using the opening 20. be able to. Moreover, since PC steel material 17a, 17b can be arrange | positioned also to the side of the opening part 20, the upper direction, and the downward direction, the prestress of the liquid barrier 2 can be introduce | transduced evenly and the liquid barrier 2 can be constructed | assembled suitably. Thereby, in the method of this embodiment, a tank can be constructed efficiently and suitably, and the construction period can be shortened.

  Further, since prestress is introduced into the region of the opening 20 closed by the concrete 22 using the additional PC steel materials 19a and 19b, the region is preferably reinforced. At this time, one end of the additional PC steel material 19a, 19b is connected to one end of the PC steel material 17a, 17b at the edge of the opening 20, and the other end is fixed to the fixing protrusion 2a in the vicinity of the opening 20. The additional PC steel materials 19a and 19b can be arranged appropriately and easily.

  Further, in this embodiment, the liquid breakwater 2 is arranged so as to be movable with respect to the bottom slab 5, and after the liquid breakwater 2 is moved inward by introduction of circumferential prestress, the liquid breakwater 2 is fixed to the bottom plate 5. Since vertical pre-stress is introduced, circumferential pre-stress can be effectively introduced into the breakwater 2 without being restrained by the bottom plate 5, and the breakwater 2 is fixed to the bottom plate 5 when completed. Tanks with excellent resistance to hydraulic pressure can be constructed.

  However, the present invention is not limited to this. For example, in the present embodiment, the pre-stress in the circumferential direction is introduced after the construction of the breakwater 2 for the entire height, but due to problems such as the stability of the breakwater 2 during construction, It is also possible to introduce circumferential prestress at the stage of construction to the height. For example, after the breakwater 2 is constructed to a height of several lots of concrete (for example, 4 lots), the PC steel material 17a corresponding to the height is tensioned. In addition, the arrangement of the PC steel materials 17a and 17b is not limited to that described in the present embodiment. For example, instead of fixing in the bottom plate 5, the PC steel material 17 b in the vertical direction is arranged so as to be bent in a U shape in the bottom plate 5, and both ends are the top edge of the liquid barrier 2 and the lower edge of the opening 20. It is also possible to fix to the part.

  Furthermore, in the present embodiment, prestress is introduced into the concrete 22 of the opening 20. However, when the width and height of the opening 20 are relatively small, for example, 2 m or less, they are prevented near the top, bottom, left, and right of the opening 20. The amount of the PC steel materials 17a and 17b in the liquid bank 2 may be increased, and an RC structure composed of reinforcing bars and concrete 22 may be used without arranging the PC steel material in the opening 20.

  Moreover, in this embodiment, the circumferential prestress was introduced by allowing the liquid breakwater 2 to be slidable with respect to the bottom plate 5, but the circumferential prestress was introduced by connecting the liquid breakwater 2 to the bottom plate 5 with a pin structure. Thereafter, the liquid breakwater 2 may be rigidly fixed to the bottom plate 5. Alternatively, it is also possible to introduce circumferential prestress in a state where the breakwater 2 is fixed to the bottom plate 5 from the beginning.

  In the present embodiment, the fixing protrusions 2a are provided in the vicinity of the right side and the lower side of the opening 20 of the liquid barrier 2. However, the positions thereof are not limited thereto. Further, as shown in FIG. 7, both ends of the additional PC steel material 19 a in the circumferential direction can be fixed to fixing protrusions 2 a provided in the vicinity of the left and right of the opening 20. Similarly, both ends of the additional PC steel material 19b in the vertical direction can be fixed to the fixing protrusion 2a provided near the top and bottom of the opening 20. This also makes it possible to appropriately arrange the additional PC steel materials 19a and 19b.

  Further, as shown in FIG. 8, it is possible to embed a reinforcing steel material 25 in the liquid barrier 2 near the opening 20, thereby reinforcing the vicinity of the opening 20. In the illustrated example, L-shaped steel materials such as perforated plates are embedded in the vicinity of the four corners of the opening 20, but the position and shape of the reinforcing steel material 25 are not limited thereto.

  Furthermore, although the above embodiment gave and demonstrated the example which constructs the breakwater 2 etc. of the LNG tank 100 as a tank, this invention is applicable also to other tanks including the LPG tank which stores LPG. is there.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

2; breakwater 2a; fixing protrusion 3a; inner tub 3b; outer tub 4; pile 5; bottom slab 7; ground 17a; circumferential PC steel 17b; vertical PC steel 19a; Additional PC steel 20; opening 21; slide 22; concrete 23; filler 25; reinforcing steel 100; LNG tanks 170, 171, 172, 192; fixing body 191;

Claims (6)

A method for constructing a tank having a side wall made of prestressed concrete,
(A) introducing the prestress into the side wall by constructing the side wall in a state of leaving an opening for construction, tensioning a tension material passed through a portion of the side wall excluding the opening, and
A step (b) of closing the opening;
Comprising
At least a part of the tendon has one end at the edge of the opening, and when the prestress is introduced by the tendon, the one end is fixed at the edge of the opening ,
In the step (b),
Concrete is placed in the opening, and prestress due to the tension of the additional tension material is introduced into the concrete,
The method of constructing a tank, wherein the additional tendon includes a tendon in a vertical direction . After constructing the inner tank of the tank,
The tank construction method according to claim 1, wherein the opening is closed in the step (b). One end of the additional tendon is connected to the one end of the tendon having one end at the edge of the opening,
The construction of the tank according to claim 1 or 2 , wherein the other end of the additional tendon is fixed to the side wall in the vicinity of the opening when prestress is introduced by the additional tendon. Method. 3. The tank construction method according to claim 1, wherein both ends of the additional tendon are fixed to the side wall in the vicinity of the opening when prestress is introduced by the additional tendon. . When introducing prestress in the step (a),
Tension the circumferential tension material of the side wall to introduce circumferential prestress to the side wall, and after the side wall has moved inward, the side wall is fixed to the bottom plate, and then the tension material in the vertical direction is tensioned method for constructing a tank according to any one of claims 1 to claim 4, wherein the introduction of vertical prestress the side wall and. A tank having a side wall made of prestressed concrete,
Prestress is introduced into the side wall by the tension of the tension material passed through the portion excluding the predetermined region of the side wall,
At least a portion of the tendon has one end at the edge of the predetermined area, and the one end is fixed at the edge of the predetermined area ,
An additional tendon is provided in the predetermined region, and prestress due to the tension of the additional tendon is introduced into the predetermined region ,
The additional tendon includes a vertical tendon .

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