JP6656875B2 - Precast member joining method - Google Patents

Description

  The present invention relates to a method for joining precast members.

  As a facility for storing liquids such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas), there is a PC (prestressed concrete) tank. FIG. 6 shows an example of an LNG tank 100 that stores LNG as a PC tank. The LNG tank 100 shown in FIG. 6 has a liquid barrier 20 provided on a bottom plate 50 supported by a pile 40 in the ground 70, and an inner tank 30a and an outer tank 30b made of a steel plate or the like are provided inside the dike 20. LNG is stored in the inner tank 30a, and a heat insulating material is arranged between the inner tank 30a and the outer tank 30b to keep cool.

  The liquid barrier 20 is a concrete cylindrical wall provided to prevent leakage of LNG to the outside when the inner tank 30a or the like is damaged, and is usually cylindrical. The breakwater 20 needs to have a structure that can withstand the liquid pressure of LNG, and therefore, a prestress is introduced by the tension of the tension member in the circumferential direction and the vertical direction.

  In order to shorten the construction period and reduce the construction cost, a method of transporting a precast concrete member (PCa member) made in advance at the factory to the construction site when assembling the dike 20, and assembling and joining it, is used. There is.

  A sheath tube for passing the tendon material is embedded in the precast member, and when joining the precast members, the sheath tubes of both precast members are connected, and a filler is filled between the precast members to be jointed. .

  FIGS. 7A to 7C are views showing the connection of the sheath tube 11 of the precast member 1. The sheath tube 11 is connected to the connection sheath tube 2 shown in FIG. A spiral screw is provided on the outer peripheral surface of the sheath tube 11 and the connection sheath tube 2, and the sheath joint 21 is fitted to both ends of the connection sheath tube 2. The inner peripheral surface of the sheath joint 21 is provided with a groove (female screw) screwed with the screw.

  The connecting sheath tube 2 is arranged between the ends of both sheath tubes 11, and the sheath joint 21 is rotated to straddle the connecting sheath tube 2 and the ends of the sheath tubes 11 as shown in FIG. So that Thereafter, as shown in FIG. 7 (c), vinyl tape 3 is wound around both ends of the sheath joint 21 to stop water, thereby preventing the intrusion of the filler.

  As another example, Patent Literature 1 describes that a heat-shrinkable member is later wound into a tube shape around a connection portion of a sheath tube, and is shrunk by heating.

JP 2015-124502 A

  In the case of the connection method as shown in FIGS. 7A to 7C, the screw of the sheath tube 2 for connection and the screw of both sheath tubes 11 need to be on the same spiral. Therefore, in a state where both precast members 1 are arranged at predetermined positions, the distance between the ends of the sheath tubes 11 of both precast members 1 is fixed, and the screw of one sheath tube 11 and the screw of the connection sheath tube 2 are the same. Even if the screw can be fitted on the spiral, the screw of the other sheath tube 11 often does not fit on the spiral, and it is difficult to connect the sheath tube 11.

  Even if the sheath tube 11 can be connected, when the both ends of the sheath joint 21 are wrapped with the vinyl tape 3, the work is performed in a space where narrow reinforcing joints (not shown) stand up. Is difficult to wrap reliably. The method of Patent Document 1 also has a similar problem because the winding operation is performed.

  Further, if the distance between the two precast members 1 is large, a long connecting sheath tube 2 is required, and if a low-rigidity material such as polyethylene or a thin steel spiral sheath is used for the connecting sheath tube 2, the connecting sheath tube 2 will be interrupted. Support is needed.

  The present invention has been made in view of the above problems, and has as its object to provide a method of joining precast members with high workability.

The present invention for solving the above-described problem is a method for joining precast members, which is a method for joining sheath tubes between both precast members when joining the precast members. Then, a tubular heat-shrinkable tube previously fitted to one of the sheath tubes is slid and placed at a position straddling the ends of both sheath tubes, and then the heat-shrinkable tubes are heated and shrunk, and the connection is established. The sheath tube is a sheath tube for the precast member and a sheath tube for connection different from the sheath tube for the precast member. After being disposed between the ends of the sheath tube, one of the heat-shrinkable tubes is slid to straddle the one end of the connecting sheath tube and the end of the sheath tube of the one precast member. By disposing the other heat-shrinkable tube at the position that straddles the other end of the sheath tube for connection and the end of the sheath tube of the other precast member, the heat-shrinkable tube is the end surfaces of the connecting sheath pipe, Ri Do a state straddling the end surface of the sheath tube of the precast member on the end surface and opposite position of the connecting sheath pipe, the end surface of the sheath tube of the precast member, said The method for joining precast members , wherein the precast member is inclined with respect to the axial direction of the sheath tube of the precast member, and the end surface of the connecting sheath tube has an inclination corresponding to the inclination of the end surface of the sheath tube of the precast member. is there.

  In the present invention, instead of the sheath joint, a heat-shrinkable tube that has been fitted to the sheath tube in advance is used. Shrink. In the present invention, since the screw is not turned as in the case of the above-mentioned sheath joint, reliable connection can be performed regardless of the screw. Also, there is no need for winding work such as the case using vinyl tape or the case of Patent Document 1. The heat-shrinkable tube shrinks only by heating with a burner and closely adheres to both sheath tubes. And high water stopping performance can be realized.

In the present invention, according to the distance between the precast members and the like, the connection of the sheath tube is performed using the connection sheath tube, and the heat-shrinkable tube is externally fitted to the connection sheath tube in advance, and is slid. Work can be done easily.
Further, in the present invention, it is preferable that a ring-shaped water stopping member is provided along the inner surface of the heat shrinkable tube .

Preferably, the connection sheath tube is a steel tube.
If a rigid steel pipe is used for the connection sheath pipe, the support need not be provided as described above. In the present invention, screws and the like are not required for the steel pipe, and the outer peripheral surface may be smooth. If a sheath joint having the above-described groove (female screw) on the inner peripheral surface is used, a gap is formed between the steel pipe and the sheath joint. However, since the present invention uses a heat-shrinkable tube instead of a sheath joint, there is no such problem.

  According to the present invention, it is possible to provide a method of joining precast members having high workability.

The figure explaining the joining method of the precast member 1 The figure explaining the joining method of the precast member 1 Diagram showing LNG tank 100a The figure which shows the sheath tube 11 'of the precast member 1', and the sheath tube 4 'for a connection. The figure explaining the joining method of the precast member 1 Diagram showing LNG tank 100 Diagram showing connection of sheath tube 11

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

[First Embodiment]
1 and 2 are views for explaining a method of joining the precast member 1 according to the first embodiment of the present invention. The method for joining the precast members 1 of the present embodiment is used for joining the precast members when constructing the liquid barrier of the LNG tank described above.

  In the present embodiment, a sheath tube 11 for passing the tendon material of the liquid barrier is buried in the concrete precast member 1, and the sheath tube 11 projects from an end surface of the precast member 1 as shown in FIG. 1. . In the present embodiment, the precast members 1 are arranged adjacent to each other such that their end faces face each other. Although a spiral screw is provided on the outer periphery of the sheath tube 11, this screw may not be provided in the present embodiment.

  For connecting the precast member 1, a connecting sheath tube 4 shown in FIG. 1 is used. A high-rigidity steel pipe is used as the connection sheath pipe 4, and the outer peripheral surface is smooth and has no screws. However, a spiral tube or the like having a screw on the outer peripheral surface can be used as the connection sheath tube 4.

  A tubular heat-shrinkable tube 41 is externally fitted to both ends of the connecting sheath tube 4 in advance. As the heat shrink tube 41, a polyolefin resin, a polyvinyl chloride resin, a silicone rubber, or the like can be used.

  In the present embodiment, the connecting sheath tube 4 is moved as shown by the arrow in FIG. 1 and the connecting sheath tube 4 is arranged between the sheath tubes 11 of both precast members 1 as shown in FIG. . Then, as shown in FIG. 2B, the heat-shrinkable tubes 41 at both ends of the connection sheath tube 4 are slid, and one of the heat-shrink tubes 41 is connected to one end of the connection sheath tube 4 and one of the precast tubes. The other heat-shrinkable tube 41 is disposed at a position straddling the end of the sheath tube 11 of the member 1, and the other heat-shrinkable tube 41 is positioned at a position straddling the other end of the connecting sheath tube 4 and the end of the sheath tube 11 of the other precast member 1. To place.

  Then, as shown in FIG. 2C, each heat-shrinkable tube 41 is heated and shrunk by a gas burner or an industrial drier. The contracted heat-shrinkable tube 41 is in close contact with the outer peripheral surfaces of the connection sheath tube 4 and the sheath tube 11, whereby connection between the connection sheath tube 4 and the sheath tubes 11 of both precast members 1 and water stop are performed.

  Thus, the sheath tubes 11 of the two precast members 1 are connected via the sheath tube 4 for connection. Thereafter, as shown in FIG. 2D, a filler 5 such as concrete or mortar is filled between the precast members 1 to form joints, and the precast members 1 are joined to each other.

  Although not particularly shown, joint reinforcements are also arranged between the precast members 1 in advance and are embedded in the filler 5. Although the example in which the left and right precast members 1 are joined has been described above, the same method can be applied when joining the upper and lower precast members 1.

  FIG. 3 is an example of the liquid barrier 20a of the LNG tank 100a constructed by joining the precast members 1. In the LNG tank 100a, the precast members 1 are arranged in the circumferential direction of the breakwater 20a and stacked vertically to form the breakwater 20a. The filler 5 is filled between the precast members 1 adjacent in the circumferential direction and the vertical direction of the liquid barrier 20a, thereby forming joints. The other configuration is substantially the same as that of the LNG tank 100 described with reference to FIG. 6. In the liquid barrier 20 a, a prestress is introduced by a circumferential and vertical tendon, and the tendon is a sheath of the precast member 1 described above. The tube is passed through the tube 11 and the connecting sheath tube 4.

  As described above, according to the present embodiment, instead of the sheath joint, the heat-shrinkable tube 41 previously fitted to the connection sheath tube 4 is used, and this is used as the connection sheath tube 4 and the sheath tube of the precast member 1. After being slid to a position straddling the end of No. 11, it is heated and shrunk by a burner or the like. In this embodiment, the connection of the sheath tubes 11 of the two precast members 1 can be performed using the connection sheath tube 4 in this manner, and the screws are not turned as in the case of the sheath joint 21 described above. Can be easily connected.

  In addition, a winding operation such as a case using a vinyl tape or the case of Patent Document 1 is not necessary, and the heat-shrinkable tube 41 shrinks only by heating with a burner or the like, so that the heat-shrinkable tube 41 comes into close contact with the connection sheath tube 4 and the sheath tube 11. Reliable work can be performed even in a narrow space where reinforcement bars stand, and high waterproofness can be realized.

  Further, in the present embodiment, since a steel tube having high rigidity is used as the sheath tube 4 for connection, it is not necessary to install the support as described above. No screws or the like are required for this steel pipe, and the outer peripheral surface may be smooth. If a sheath joint 21 having the above-described groove (female screw) on the inner peripheral surface is used, a gap is formed between the steel pipe and the sheath joint 21. Therefore, it is difficult to reliably stop water. However, in the present embodiment, since the heat-shrinkable tube 41 is used instead of the sheath joint 21, there is no such problem.

  However, the present invention is not limited to this. For example, the joining method of the precast member 1 of the present embodiment is applicable not only to the dike 20a but also to the construction of various structures.

  Further, the heat-shrinkable tube 41 may be fitted to the sheath tube 11 instead of the sheath tube 4 for connection in advance. However, in this case, the fitting of the heat-shrinkable tube 41 to the sheath tube 11 may be a work between the precast members 1, and it is better to fit the heat-shrinkable tube 41 to the connection sheath tube 4 in advance. Is easy.

  Further, the shapes of the sheath tube 11 and the connecting sheath tube 4 are not particularly limited. For example, as shown in the precast member 1 'of FIG. 4, the end surface of the sheath tube 11' may be inclined with respect to the axial direction of the sheath tube 11 ', and in this case, both end surfaces of the connecting sheath tube 4' By providing an inclined surface corresponding to this inclination, workability at the time of installing the connecting sheath tube 4 'is improved, and the connecting sheath tube 4' can be smoothly installed between the ends of the sheath tube 11 '. . In the example of FIG. 1 and the like, the length of the connecting sheath tube 4 is slightly shorter than the interval between the ends of the sheath tube 11 in consideration of the workability at the time of installation, but in the example of FIG. No need. In the present invention, since connection is not performed by turning a screw as in the case of the sheath joint 21, the shape of the sheath tube 11 'and the connecting sheath tube 4' as shown in FIG. 4 can be obtained.

  Further, a heat-meltable adhesive may be provided on the inner surface of the heat-shrinkable tube 41. In this case, when the heat-shrinkable tube 41 is heated and shrunk, the heat-shrinkable tube 41 and the connecting sheath tube 4 and the sheath are welded by the adhesive. Adhesion with the pipe 11 is further enhanced, and water can be stopped more reliably. Similarly, it is also possible to provide a ring-shaped water-stopping member along the inner surface of the heat-shrinkable tube 41, so that when the heat-shrinkable tube 41 contracts, water can be stopped more reliably.

  Next, a second embodiment of the present invention will be described. The second embodiment will be described with respect to differences from the first embodiment, and the same points will be denoted by the same reference numerals in the drawings and the like, and description thereof will be omitted.

[Second embodiment]
Drawing 5 is a figure explaining a joining method of precast member 1 concerning a 2nd embodiment of the present invention. The second embodiment is an example in which the ends of the sheath tubes 11 of both precast members 1 are directly connected by a heat-shrinkable tube 41.

  That is, in the present embodiment, the heat-shrinkable tube 41 is fitted on the sheath tube 11 of one precast member 1 in advance, and after the two precast members 1 are arranged as shown in FIG. Then, as shown in FIG. 5 (b), the precast members 1 are arranged at positions over the ends of the sheath tubes 11 of the two precast members.

  Then, as shown in FIG. 5C, the heat-shrinkable tube 41 is heated and shrunk by a burner or the like. As a result, the connection of the sheath tubes 11 of both the precast members 1 and the stoppage of water are performed as described above. Subsequent steps are the same as in the first embodiment, and the precast members 1 are joined to each other by filling a filler between the precast members 1.

  In the second embodiment, the same effect as in the first embodiment can be obtained, and when the distance between the precast members 1 is relatively small, such a joining method is also possible.

  As described above, the preferred embodiments of the present invention have been described 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 made within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. I understand.

1, 1 '; precast members 2, 4, 4'; connecting sheath tube 5; filler material 11, 11 '; sheath tube 21; sheath joint 41; heat-shrinkable tubes 20, 20a; tank

Claims (2)

When joining the precast members, a method of joining the precast members to connect the sheath tubes between the two precast members,
When connecting sheath tubes,
Slide the tubular heat-shrinkable tube that was previously fitted to one of the sheath tubes, and after arranging it at a position straddling the ends of both sheath tubes, heat and shrink the heat-shrinkable tube,
The sheath tube to be connected is a sheath tube for the precast member and a sheath tube for the connection that is different from the sheath tube for the precast member,
After arranging the connecting sheath tube in which the two heat-shrink tubes are fitted in advance, between the ends of the sheath tubes of both precast members,
One of the heat shrink tubes is slid so as to be arranged at a position straddling one end of the sheath tube for connection and the end of the sheath tube of one precast member, and the other heat shrink tube is slid for the connection. By arranging the other end of the sheath tube and the end of the sheath tube of the other precast member over the end of the sheath tube, the heat-shrinkable tube has an end surface of the connecting sheath tube and an end surface of the connecting sheath tube. state straddling the end surface of the sheath tube of the precast member which is in opposite position with Do Ri,
The end face of the sheath tube of the precast member is inclined with respect to the axial direction of the sheath tube of the precast member,
The method for joining precast members , wherein an end surface of the connecting sheath tube has an inclination corresponding to an inclination of an end surface of the sheath tube of the precast member.   2. The method for joining precast members according to claim 1, wherein a ring-shaped water blocking member is provided along an inner surface of the heat-shrinkable tube.

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