JP2019143323A - Method for joining precast concrete member - Google Patents

Abstract

To prevent, in a precast concrete member on site, infiltration of a filler into a sheath pipe and to improve efficiency of construction in a method for joining a precast concrete member on a site by using a tendon.SOLUTION: Concerning a tube 20 comprising a plurality of expansion parts 22 which are expanded to a diameter larger than the diameter of a sheath pipe 12 of a precast member 10 and are arranged at a prescribed interval in the extension direction and comprising a restraint part 23 located between the plurality of expansion parts 22, for the purpose of the tube, formed by reducing the diameter of the restraining portion 23, is in communication with the sheath pipe 12, the expansion part 22 is inserted into the sheath pipe 12 of each precast member 10 adjacent to each other with a predetermined gap J so that both ends thereof are positioned within the sheath pipe 12 by a predetermined length across the gap J. Then, air is injected into the tube 20 to expand the expansion part 22 so as to be in close contact with the inner peripheral surface of the sheath pipe 12, thereby closing the open end of each sheath pipe 12 and forming an insertion space for the tension material in the gap J.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for joining precast concrete members, and more particularly to a method for joining precast concrete members connected by a tension material such as a PC cable.

  In a concrete structure, various precast concrete members (hereinafter referred to as PCa members) manufactured in advance in a factory are often used in order to rationalize construction and shorten the construction period. When connecting the PCa members of the prestressed concrete by the post-tension method, the joint portion between the PCa members is joined by a dry joint or a wet joint. When joined by a wet joint, a grout material such as non-shrink mortar is filled between the joining surfaces of the PCa member. However, it is necessary to prevent the grout material from entering the sheath tube of the PCa member from the small edge of the PCa member at the time of filling. is there.

  In order to cope with this problem, in Patent Document 1, the tube (expansion mold 20) inserted into the sheath pipe is expanded to close the sheath pipe, and after filling the joint portion with the filler, the expansion mold 20 is extracted. A joining method for preventing the filler from entering the sheath tube is disclosed.

JP 2017-71996 A

  However, in the joining method described in the first embodiment such as FIG. 1 to FIG. 3 of Patent Document 1, since the rubber inflatable mold 20 (tube) is inserted into the sheath tube as it is, the inflatable mold 20 is inside the sheath tube. It is not easy to get the expansion die 20 inserted over the entire length of the sheath tube by being caught by the unevenness. In addition, the expansion mold 20 may be damaged by the irregularities inside the sheath tube during insertion, the expansion mold 20 cannot be expanded, and the infiltration of the filler into the sheath tube may not be prevented.

  Therefore, an object of the present invention is to improve the efficiency of construction by improving the penetration of the tube, which is a protective material for preventing the filler from entering the sheath tube, when the joint between the PCa members is joined. An object of the present invention is to provide a method for joining precast concrete members that improves and reduces the possibility of tube breakage.

  In order to achieve the above object, the present invention is a joining method for joining a plurality of precast concrete members with a tension material wired inside a through hole, and is expandable to a diameter larger than the diameter of the through hole. A tube formed by narrowing the diameter of the restraining portion, a plurality of inflating portions arranged at predetermined intervals in the extending direction, and a restraining portion located between the plurality of inflating portions, In each of the precast concrete members adjacent to each other by providing a predetermined gap so that the through holes communicate with each other, the inflating portion straddles the predetermined gap and both ends have the predetermined length. Inserting the fluid so as to be positioned inside, inflating the expansion portion so as to be in close contact with the inner wall of the through-hole by injecting a fluid into the tube, closing the open end of each through-hole, and Place Forming an insertion space of the tendons in the gap, characterized in that it comprises a and a step of filling a filler in the gap.

  The constraining portion may be formed such that a diameter of the constraining portion is reduced by folding a part of the tube.

  The tube may further include a through-hole inflating portion, and fluid may be injected into the tube so that the through-hole inflating portion is closely fixed to the inner peripheral surface of the through-hole.

  It is preferable that a guide member is attached to the tip of the tube.

  The restraining portion is preferably formed by winding a tape around the tube.

  According to the present invention, when joining a joint between PCa members, it is possible to improve the construction efficiency by improving the tube insertion property for preventing the filler from entering the sheath tube. Moreover, possibility that a tube will be damaged can be reduced.

(A) is a perspective view of a structure of a PCa member according to an embodiment of the present invention, (b) is a side view of (a), and (c) is a side sectional view of a tube used in the embodiment of the present invention. Figure. (A) is an expanded sectional perspective view of the structure of the PCa member which concerns on embodiment of this invention, (b) is an expanded side sectional view of (a). (A) is side surface sectional drawing of the tube penetration process of the joining method of the structure which concerns on embodiment of this invention, (b) is side surface sectional drawing of the tube expansion process. (A) is an enlarged side sectional view of the tube insertion step of the PCa member joining method according to the embodiment of the present invention, (b) is an enlarged side sectional view of the tube expansion step, and (c) is the joint portion. The expanded side surface sectional drawing of a grout material filling process. (A) is side sectional drawing at the time of the compressed air injection | pouring of the tube used for a modification, (b) is side sectional drawing at the time of the compressed air non-injection of the tube used for another modification.

  A method of joining the structure 1 such as a box culvert formed by a PCa member connected by a tension member (PC steel material) of the present invention by a wet joint will be described below with reference to the accompanying drawings.

  FIG. 1A is a view showing the inside of a formwork in which a reinforcing bar assembly assembled with a necessary cover thickness is arranged in a precast concrete member manufacturing factory constructed in an embodiment of the joining method according to the present invention. The PCa members 10-1, 10-2,..., 10-n manufactured by placing concrete on are shown. In the present embodiment, FIG. 1A shows a prestressed concrete box culvert constructed as a PCa member 10 by a post-tension method in the longitudinal direction on site. In the PCa member main body 11 shown in FIG. 1B, a sheath tube 12 forming a through hole through which a PC cable as a tension material is inserted into the PCa member 10 is arranged (FIG. 1A).

  As shown in FIGS. 3A and 3B, the joint portion J of the structure 1 having the full length Lc formed by the PCa members 10-1, 10-2, 10-3,. By using the tube 20 shown in FIG. 1C, each open end of the sheath tube 12 is closed, and the filling material 30 is filled while maintaining a state in which the tension material can be inserted through the joint portion J in the longitudinal direction. . For example, as illustrated in FIGS. 2A and 2B, the bonding portion J has a predetermined interval (gap) between the bonding surface A of the PCa member 10-1 and the bonding surface B of the PCa member 10-2. And are formed to face each other. Before filling the joint portion J with the filler 30, the expansion portion 22 of the tube 20 is connected to the joint portion J, the opening 13 on the joint surface A side of the sheath tube 12 of the PCa member 10-1, and the sheath tube of the PCa member 10-2. The expansion portion 22 is inflated by injecting fluid such as compressed air into the tube 20. When the inflating portion 22 expands, the opening 13 and the opening 14 are blocked, the inflow of the filler 30 into the sheath tube 12 is prevented, and a space for inserting a tension material is secured at the joint portion J.

  The joint portion J between the PCa member 10-2 and the PCa member 10-3, the joint portion J between the PCa member 10-3 and the PCa member 10-4,... Are the same as the PCa member 10-1 and the PCa member 10-2. Therefore, the description is omitted.

[Construction method for joint J]
Hereinafter, the joining method of the joining portion J of the PCa member will be described with reference to each drawing. This joining method is comprised from the PCa member arrangement | positioning process, the tube insertion process, the tube expansion process, the junction part grout material filling process, and the tension | tensile_strength process.

  As shown in FIG. 1C, the tube 20 used in the present embodiment has a full length L (L> Lc) except for a wire P described later. The tube 20 has a cylindrical shape having an outer diameter D2 that is thinner than the inner diameter DS of the sheath tube 12, as shown in FIG. In this embodiment, a synthetic rubber product such as styrene-butadiene rubber or chloroprene having elasticity is used as the tube 20. In order to improve the durability of the tube 20, a product with fiber reinforcement may be used. An off-the-shelf product such as an air mold such as a gap guard (registered trademark) for closing the joint can be used for the tube 20. As shown in FIGS. 3A and 3B, the tube 20 has a through-hole inflating portion 21, an inflating portion 22, a restraining portion 23, and a tip inflating portion 24 in the extending direction in consideration of the function performed at the time of expansion. The rear end inflatable portion 25 can be divided. As shown in FIG. 2B, the tube 20 has an outer diameter D2 that is usually thinner than the inner diameter DS of the sheath tube 12. However, when a fluid such as compressed air is injected, the tube 20 expands beyond the inner diameter DS of the sheath tube 12. can do. Further, a wire P is connected to the distal end inflating portion 24 of the tube 20 and is closed.

Here, the arrangement | positioning condition in the PCa member 10 of the tube 20 is demonstrated.
As shown in FIGS. 2A, 2B, and 3A, the in-hole expanding portion 21 of the tube 20 is disposed inside the sheath tube 12 of the PCa member 10-1 and the PCa member 10-2. The When compressed air is injected into the tube 20, as shown in FIG. 3 (b), the in-hole expanding portion 21 expands, the tube 20 comes into close contact with the inner peripheral surface of the sheath tube 12, and the tube 20 is a sheath. Fixed in the tube 12. The expansion part 22 is arrange | positioned ranging over the junction part J (gap E (E1)), the opening 13, and the opening 14 as mentioned above. When compressed air is injected into the tube 20, the expansion portion 22 expands and the opening 13 and the opening 14 are closed. Thereby, when the filler 30 is filled in the joint portion J, the filler 30 is prevented from flowing into the sheath tube 12 as shown in FIG. Space is secured. The restricting portion 23 is arranged so as to communicate the through-hole inflating portion 21 and the inflating portion 22 (including the tip inflating portion 24 and the rear end inflating portion 25). In the present embodiment, the restraining portion 23 is formed by winding an adhesive tape around the tube 20 folded in the radial direction including the in-hole inflating portion 21 and the inflating portion 22 and has a diameter of D3. As a result, the outer diameter D2 of the maximum diameter (expanded portion 22) of the tube 20 at normal time (when the compressed air is not filled) is smaller than the outer diameter D1 of the original tube 20, but when the tube 20 expands, the sheath 20 The inner diameter DS of the tube 12 is greater than or equal to.

  As shown in FIG. 3A, the wire P is connected to the tip of the tip inflating portion 24. The tip of the tip inflating portion 24 protrudes from the sheath tube 12. The wire P is a guide (guide member) for passing the tube 20 through the sheath tube 12. The rear end of the distal end inflating portion 24 is disposed in the sheath tube 12 of the PCa member 10 in the same manner as the inflating portion 22. A marker M for positioning the tube 20 is attached to the distal end inflating portion 24. The rear end of the rear end inflating portion 25 protrudes from the sheath tube 12, and an air compressor (not shown) for injecting compressed air into the tube 20 is connected via a check valve.

(PCa member placement process)
In the PCa member arranging step, as shown in each drawing of FIG. 2 and FIG. 3A, the joining surface A in the longitudinal direction of the PCa member 10-1 and the joining surface B in the longitudinal direction of the PCa member 10-2 are as shown in FIG. The sheath tubes 12, 12 are arranged so as to face each other with a predetermined gap W2. In the present embodiment, the predetermined gap W2 is set to about 20 mm. W2 is appropriately set according to the scale of the structure, workability, and the like.

(Tube insertion process)
When inserting the tube 20 into the PCa member 10, as shown in FIG. 4A, the expansion portion 22 of the tube 20 is joined to the joint portion J (gap E) and the joint surface A of the sheath tube 12 of the PCa member 10-1. It arrange | positions so that the opening 13 of the side and the opening 14 of the joint surface B side of the sheath pipe | tube 12 of the PCa member 10-2 may be straddled. As shown in FIG. 2B, a sufficient predetermined length F is secured from the openings 13 and 14 so that the filler 30 does not enter. In the present embodiment, the tube 20 has a width W1 of the PCa member 10 shown in FIG. 2A, a width W2 of the joint portion J, and the tube 20 so that the center of the joint portion J is disposed at the center of the inflating portion 22. The length L1 of the expansion part 21 in the through hole, the length L2 of the expansion part 22, and the length L3 of the restraint part 23 are arranged so that W1 + W2 = L1 + L2 + 2L3. At this time, assuming that a portion of the inflating portion 22 that does not contact the sheath tube 12 even when inflating is S, L2 = 2S + 2F + W2, as shown in FIG. Further, the length L4 to the marker M of the distal end inflating portion 24 shown in FIG. When the position of the marker M is arranged on the end surface C on the opposite side of the joint surface A of the PCa member 10-1, the position of the marker M is determined so that the position of the tube 20 has the above-described positional relationship. When the compressed air is exhausted from the tube 20, the tube 20 is slightly shortened in the length direction. Therefore, when determining the position of the marker M, it is preferable to consider the amount of shortening of the tube 20 in advance.

(Tube expansion process)
As shown in FIGS. 2B and 3B, in the tube expansion step, compressed air is supplied to the tube 20 from an air compressor or the like (not shown) connected to the rear end expansion portion 25 of the tube 20, and the through hole The inner expanding portion 21, the expanding portion 22, the leading end expanding portion 24, and the trailing end expanding portion 25 are expanded until the diameter DS of the sheath tube 12 becomes equal to or larger. As shown in FIG. 4B, when the inflating portion 22 is inflated, the opening 13 and the opening 14 are closed, and the opening 13 and the opening 14 are separated from the joint portion J (gap E (E1)). At this time, as shown in FIGS. 2A and 3A, it is confirmed that the position of the marker M of the expanded tip inflating portion 24 is not shifted from the end surface C.

(Joint Grout Filling Process)
As shown in FIG. 4C, in the joint grout material filling step, the joint E is filled with the grout material 30 by using the known joint retainers 40 and 40 to surround the gap E. After the grout material 30 is sufficiently dried, the air in the tube 20 is exhausted, and the tube 20 with a reduced diameter is extracted from the sheath tube 12.

(Tension process)
In the tensioning step, a PC cable (not shown) as a tensioning material is inserted into the sheath tubes 12 and 12 and the hole 50 formed in the joint portion J by the inflating portion 22 shown in FIG. Thereafter, one end of the PC cable is fixed to the end surface C shown in FIG. 3B using a known fixing tool (not shown). Subsequently, the other end of the PC cable is fixed to the end surface D by applying a predetermined tension to the PC cable using a known tension fixing tool (not shown) using a hydraulic pump and a jack (not shown). . After fixing the PC cable, the sheath tube 12, 12 is filled with a grout material to form the structure 1 shown in FIG.

[Tube modification]
As a modification of the tube 20, a tube 20A as shown in FIG. In the tube 20 </ b> A, the restraining portion 23 </ b> A corresponding to the restraining portion 23 of the tube 20 is long in the long axis direction of the tube 20 </ b> A, and there is no part corresponding to the through-hole inflating portion 21. In the tube 20A, only the expansion portion 22 exposed at the joint portion J (FIG. 2) expands, so the time for injecting compressed air into the tube 20A can be shortened. Further, by configuring the outer side of the restraining portion 23A with a material having a low friction coefficient, the insertion property of the restraining portion 23A can be increased, and the time for inserting the tube 20A into the sheath tube 12 can be shortened. The possibility of being caught inside and the possibility of breakage can be reduced, and the construction time can be shortened.

  As a modification of the tube 20, a tube 20B as shown in FIG. 5B will be described. In the tube 20B, the constraining portion 23B corresponding to the constraining portion 23 of the tube 20 is long in the long axis direction of the tube 20B, there is no portion corresponding to the through-hole inflating portion 21, and the inflating portion 22B corresponding to the inflating portion 22 Has a larger diameter than the restraining portion 23 even when air is not injected. Even in the tube 20B, only the expansion portion 22B exposed at the joint portion J (FIG. 2) expands. Moreover, since the expansion part 22B has a large diameter, the time for injecting air into the tube 20B can be shortened. Furthermore, since the expanded portion 22B has a large diameter, it is possible to confirm that the expanded portion 22B is disposed in the bonded portion J by visually observing the bonded portion J.

  In this embodiment, the restraining portion 23 is formed by winding an adhesive tape around the tube 20 folded in the radial direction, but instead of the adhesive tape, a thin metal plate or a synthetic resin that can be easily folded is wound. By turning and forming the restraining portion 23, the strength and the insertability of the restraining portion 23 can be increased. Alternatively, the restraining portion 23 may be formed by attaching a rubber ring or the like having the same diameter as the restraining portion 23 to the tube 20. Further, the restraining portion 23 may be formed by changing the weaving method of the reinforcing fibers of the tube 20 to form a portion where the reinforcing fibers hardly expand or contract.

  In the present embodiment, the restraining portion 23 is formed by folding the tube 20 in the radial direction, but the tube 20 may be wound in a spiral shape to reduce the diameter of the tube 20.

  In the present embodiment, the present joining method is used in the longitudinal direction, but can also be applied in the transverse direction when the PCa member 10 is divided in the transverse direction.

  The present invention is not limited to the above-described embodiments, and various modifications within the scope of the claims are possible. In other words, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Structure 10 PCa member 11 PCa member main body 12 Sheath pipe | tube (through-hole)
13, 14 Opening 20, 20A, 20B Tube 21 Expanding part in through hole 22, 22B Expanding part 23, 23A, 23B Restraining part (restraining member)
24 Front end expansion part 25 Rear end expansion part 30 Grout material J Joint part A, B Joint surface C, D End face E, E1, E2 Gap (gap)
P wire (guide member)

Claims (5)

A joining method for joining a plurality of precast concrete members with a tension material wired inside a through hole,
A plurality of inflatable portions that can be inflated to a diameter larger than the diameter of the through-holes and arranged at predetermined intervals in the extending direction, and a restraint portion that is positioned between the plurality of inflatable portions, The tube formed by reducing the diameter,
In the through holes of the precast concrete members adjacent to each other by providing a predetermined gap so that the through holes communicate with each other, the inflating portion straddles the predetermined gap and both ends penetrate the predetermined length by the predetermined length. A step of passing through the hole so as to be located in the hole;
Fluid is injected into the tube to inflate the inflating part so as to be in close contact with the inner wall of the through-hole, thereby closing the open end of each through-hole and providing the insertion space for the tension material in the predetermined gap. Forming, and
Filling the gap with a filler;
A method for joining precast concrete members, comprising:   The method of joining precast concrete members according to claim 1, wherein the constraining portion is formed such that a diameter of the constraining portion is reduced by folding a part of the tube. The tube further includes a through-hole expanding portion,
The method for joining precast concrete members according to claim 1, wherein a fluid is injected into the tube, and the inflated portion in the through hole is closely fixed to the inner peripheral surface of the through hole.   The method for joining precast concrete members according to claim 1, wherein a guide member is attached to a tip of the tube.   The method of joining precast concrete members according to claim 1 or 2, wherein the restraining portion is formed by winding a tape around the tube.

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