JP2017071937A - Fixture reinforcement structure and fixture reinforcement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixture reinforcement structure, which is free from improper placement, capable of withstanding split tensile stress acting on a concrete part around a fixture of a PC (press concrete) structure with excellent toughness by setting a proper reinforcement ratio, and a fixture reinforcement method.SOLUTION: A fixture reinforcement structure 1 is used for preventing split tensile stress which acts around an anchorage device 4 of a PC structure A. A spiral reinforcement 5 which has a spiral shape is set from one reinforcement around the anchorage device 4 in a double winding manner so that the outer periphery surfaces of the spiral neighboring reinforcements are in contact with each other two times or more near ends at the outer surface; and the rest of which is formed so that the outer periphery surfaces of the spiral neighboring reinforcements are separated from each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fixing member reinforcing structure and a fixing tool reinforcing method for a PC (prestressed concrete) structure.

  Conventionally, when prestressing is applied to a PC (prestressed concrete) structure by a post-tension method, a tension material such as a PC steel material inserted into a sheath (tube) is tensioned, and the end of the tensioned tension material is Tighten with the anchor head. The anchor head is fixed to the concrete by fixing the anchor head with a fixing plate integrated with a fixing plate and a heel for transmitting a prestress force, and the tension force of the tension material is applied to the concrete portion of the structure through the fixing device. It is transmitted as a compressive force to give prestress to the structure.

  As described above, when prestress is introduced into a concrete structure, a large compressive stress acts on the concrete portion near the fixing tool via the fixing plate (supporting plate) of the fixing tool, and the outside side is expanded in diameter. A split tensile stress is generated in a direction perpendicular to the compressive stress by a force that the frustum-shaped fixing tool tries to sink into the structure with a tension force.

  For this reason, the fixing tool is provided with a fixing plate for evenly distributing the compressive stress to the concrete so as to be orthogonal to the tension material, and in the concrete near the fixing tool, it resists the splitting tensile stress. The reinforcing bars of the fixing tool such as spiral bars and grid bars are arranged to prevent splitting in the vicinity of the fixing tool.

  For example, Patent Literature 1 describes a fixing device reinforcement structure in which spiral streaks 32 are arranged around a guide 18 that is a fixing device (see FIGS. 1 and 5 in the drawing of Patent Literature 1). .

  However, depending on the size and conditions of the prestress to be introduced, the spiral muscle 32 alone as described in the fixing member reinforcing structure described in Patent Document 1 cannot resist the split tensile stress acting, and the crack progresses. As a result, there was a problem that the concrete could not be restrained and destroyed.

  For this reason, in a fixing structure for a PC structure that introduces a relatively large prestress, generally a hoop bar having a substantially rectangular shape is additionally arranged as a spare bar (core bar) in addition to a spiral bar. Yes. However, if you do so, the reinforcing bars will be arranged too densely around the fixing tool, that is, the ratio of reinforcing bars will be too high, and the coarse aggregate of concrete will not pass between these reinforcing bars, resulting in poor placement such as junkers. There was a problem that occurred.

  In addition, when the fixing plate is smaller than the reinforcing bar winding diameter and is appropriately reinforced, the fixing plate has a tough fracture property, but the fixing plate is about the reinforcing bar winding diameter, and When the reinforcement is excessive (when the reinforcing bar ratio is too high), it becomes a fixing device reinforcement structure that exhibits brittle fracture properties, and there is a problem that it is dangerous to brittle fracture when stress exceeding the design strength is applied. .

JP 2014-218828 A

  Therefore, the present invention has been devised in view of the above-mentioned problems, and the object of the present invention is to counter the splitting tensile stress acting on the concrete portion around the fixing member of the PC structure, and the ratio of the reinforcing bars. It is an object of the present invention to provide a fixing tool reinforcing structure and a fixing tool reinforcing method capable of exhibiting excellent toughness with less risk of placement failure.

  A fixing device reinforcing structure according to a first aspect of the present invention is a fixing device reinforcing structure for resisting split tensile stress acting around a fixing device of a PC structure, and a spiral spiral line is formed so as to surround the fixing device. This spiral rebar is double-wound from one rebar so that the outer surface side of the outer surface side of the rebar is in contact with the outer peripheral surface of two or more spiral adjacent rebars over two or more rounds. The remaining portion is formed such that the outer peripheral surfaces of adjacent spiral reinforcing bars are separated from each other.

  The fixing device reinforcing structure according to a second aspect of the present invention is characterized in that, in the first aspect of the invention, the spiral outer diameter of the spiral line is larger than the maximum distance between the ends of the fixing plate of the fixing unit.

  In the fixing device reinforcing structure according to a third aspect of the present invention, the winding outer diameter of the spiral streaks is 1.3 times or more and 1.5 times or less the outer diameter or long side distance of the fixing plate of the fixing device. It is characterized by becoming.

  A fixing tool reinforcing method according to a fourth aspect of the present invention is a fixing tool reinforcing method for reinforcing against a split tensile stress acting around a fixing tool of a PC structure, from one reinforcing bar to an end on the outer surface side. In the vicinity of the part, the outer peripheral surface of the adjacent reinforcing bars of the spiral is double wound so that the outer peripheral surfaces of the adjacent spiral reinforcing bars are in contact with each other over two or more times, and the outer peripheral surface of the adjacent reinforcing bars of the spiral is separated from each other. The spiral streak forming step of installing the spiral streak so as to surround the fixing device is provided.

  According to the first to fourth inventions, it is possible to effectively counter the splitting stress that increases in the vicinity of the outer surface with the double winding of the spiral muscle, and the remaining portion is only the normal spiral muscle, It is possible to prevent the occurrence of poor placement, and to exhibit excellent toughness.

  In particular, according to the second invention, in addition to the above-mentioned effects, the spiral outer diameter of the spiral bars is larger than that of the fixing plate, so the range of concrete that can be restrained by the spiral bars is increased, and brittle fracture is more effective. Can be prevented.

  In particular, according to the third aspect of the invention, in addition to the above-described effects, the location of the spiral muscles is appropriate, i.e., the spiral muscles are located on the outer side and in the immediate vicinity of the fixing tool. It is possible to effectively counter the splitting tensile stress caused by the inward indentation and the surrounding concrete expanding outward.

It is a vertical sectional view showing the fixing tool reinforcing structure according to the embodiment of the present invention. It is the front view which looked at the trumpet sheath of the fixing tool reinforcement structure same as the above in the direction orthogonal to a tube axis with the grout discharge port facing up. It is the left view which looked at the trumpet sheath same as the above from the fixing tool side in the tube axis method. It is the top view which looked at the trumpet sheath same as the above from the grout outlet side orthogonal to a pipe axis. FIG. 2 is a front view of a fixing tool main body of the fixing tool reinforcing structure of FIG. 1 as viewed in a direction orthogonal to a tube axis. It is the left view which looked at the fixing tool main body same as the above along the pipe axis from the outer surface side. It is the right view which looked at the fixing tool main body same as the above along the pipe axis from the inside. It is the photograph which shows the crack condition by the loading test of the test body which embed | buried the type 1 fixing tool by comparison with the past and this invention. It is the photograph which shows the crack condition by the loading test of the test body which embed | buried the type 2 fixing tool by comparison with the past and this invention. It is a graph which shows the measured value of the amount of penetration of the test body which embed | buried the type 1 fixing tool by comparison with the past and this invention. It is a graph which shows the measured value of the amount of penetration of the test body which embed | buried the type 2 fixing tool by comparison with the past and this invention. It is a graph which shows the measurement result of the strain gauge attached to the 3rd stage (3rd round: the 1st round of a general part) from the upper stage of spiral muscles. It is a graph which shows the measurement result of the strain gauge attached to the uppermost stage (double winding part) of a spiral muscle. It is a flowchart which shows each process of the fixing tool reinforcement method which concerns on embodiment of this invention.

  Hereinafter, an embodiment for carrying out a fixing tool reinforcing structure according to the present invention will be described in detail with reference to the drawings.

  First, a fixing tool reinforcing structure according to an embodiment of the present invention will be described with reference to FIGS. An example applied to a fixing tool when prestress is applied to the precast PC structure A by a post-tension method will be described.

  As shown in FIG. 1, the fixing device reinforcing structure 1 according to the present embodiment includes a hollow cylindrical sheath (tube) 2 embedded in the PC structure A, and the PC structure A inserted through the sheath 2. A tension member 3 for applying prestress to the fixing member 4, a fixing member 4 for transmitting the tension force of the tension member 3 to the concrete portion of the PC structure A and fixing the end portion of the tension member 3, and the fixing member 4 It is comprised by the spiral spiral muscle 5 etc. which are arrange | positioned in this.

(sheath)
As shown in FIG. 1, the sheath 2 includes a plurality of spiral sheaths 20 (only one is shown) that is a general part of the sheath 2, a joint sheath 21 that connects these spiral sheaths 20, and the outer surface of the sheath 2. The trumpet sheath 22 is disposed at the end on the side and includes a grout discharge port 24. The sheath 2 has a function of securing a space in which the tendon 3 can be inserted into the PC structure A. And in this sheath 2, the grout which is a time hardening material is inject | poured and filled for the rust prevention of the tension material 3 mentioned later.

  The spiral sheath 20 is a light-weight wound tube formed by winding a thin steel strip having a thickness of about 0.25 to 0.6 mm into a substantially cylindrical shape. In order to increase rigidity, beads and ribs are spirally formed. Also good. Of course, the spiral sheath 20 is not limited to a normal steel plate, and may be formed from a galvanized steel plate or a stainless steel plate, or may be made of a resin such as a high-density polyethylene pipe.

  The joint sheath 21 is a tube material having a diameter that fits over the spiral sheath 20 in order to connect the spiral sheaths 20 to each other, and is formed of the same material as the spiral sheath 20.

  2 to 4, the trumpet sheath 22 includes a cylindrical main body 23 processed into a cylindrical shape from a thin steel plate having a thickness of about 1 mm such as a cold rolled steel plate (SPCC). A cylindrical grout discharge port 24 (or injection port) having a smaller diameter is formed so as to communicate orthogonally, and a connection joint for connecting and connecting the spiral sheath 20 and the fixing device 4 via the joint sheath 21. As a function.

  As shown in FIGS. 2 and 4, the cylindrical main body 23 is formed such that the pipe end on the fixing tool 4 side has a small pipe diameter and the other end has a large pipe diameter. Two beads (25, 26) having a diameter expanded into a semicircular cross section by roll processing or the like are formed.

  As shown in FIG. 1 and the like, the bead 25 on the fixing tool 4 side, which is the outer surface side of these two beads, comes into contact with the pipe end of the fixing tool 4 when inserted into the fixing tool 4. The other bead 26 is formed at a position where it comes into contact with the tube end of the joint sheath 21 when fitted into the joint sheath 21, and the trumpet sheath 22 is fixed at a predetermined position.

  In addition, as shown in FIGS. 3 and 4, two hemispherical locking protrusions 27 that are locked in locking grooves of the fixing device 4 described later protrude from the outer peripheral surface of the cylindrical main body 23. These two locking projections 27 are fitted into the locking grooves of the fixing device 4 so that the trumpet sheath 22 is locked and attached to the locking grooves of the fixing device 4 (see FIG. 1). ).

(Tension material)
The tendon 3 according to the present embodiment is a PC steel wire or a PC steel strand that satisfies the standards of JIS G 3536 (PC steel wire and PC steel strand) (see FIG. 1). Of course, as this tendon, JIS G 3109 (PC steel bar) standard made of high strength steel (structural steel) that is hot rolled carbon steel or other chilled steel and then finished by stretching etc. It is conceivable to apply a PC steel bar that fills, and it is also possible to apply a wire or a wire having a desired strength that can withstand prestressing tension, such as carbon fiber, instead of a steel material.

(Fixing device)
As shown in FIG. 1, the fixing tool 4 according to the present embodiment includes an anchor head 40 that is inserted and tightened through an end portion of the tension member 3, and a fixing plate (supporting plate) that receives the anchor head 40. It is composed of a main body 41 and the like, embedded in the vicinity of the outer surface of the PC structure A, and has a function of fixing the end of the tension member 3 by transmitting the tension force of the tension member 3 to the concrete portion of the PC structure A. ing.

  The anchor head 40 is also called a fixing block, and is a flat columnar steel material having a plurality of insertion holes through which the end of the tension member 3 is inserted, and the end of the tension member 3 that is tensioned by a tension jack is wedged. It has the function to latch at a predetermined position.

  As shown in FIGS. 5 to 7, the fixing device main body 41 includes a ring-shaped fixing plate portion 42 in which an end portion on the outer surface side of the PC structure A on the pressure-bearing side has a function of a fixing plate (pressure-bearing plate). The fixing plate portion 42 and a hollow frustum-shaped (cup-shaped) wedge portion 43 that is continuously reduced toward the inner surface side of the PC structure are integrally formed members.

Of course, the fixing device body 41 is not particularly limited in material as long as it has a required strength, but is preferably a casting made of metal (casting) from the viewpoint that a complicated shape can be easily formed. In view of this, for example, a spheroidal graphite cast iron product (Ferrum Casting Ductile) (FCD450) having a tensile strength of 450 N / mm ² or more is preferable.

  As shown in FIG. 6, the fixing plate portion 42 is a ring-shaped portion having an outer diameter of a length L when viewed from the front. A pair of bolt grooves 44 to be used is projected. In addition, a slit 45 that is a water passage groove for grout at the time of grout injection is formed in front of the fixing plate portion 42. The fixing plate portion 42 according to this embodiment has an outer diameter L of 138 mm or 166 mm.

  In addition, when performing tension work using a jack, it is necessary to create a space for installing the jack around the anchor head 40. This space is grouted to protect the anchor head 40 from outside air after the tension work is completed. Is filled. At this time, the grout filled in the sheath from the grout hose attached to the trumpet sheath 22 wraps around the anchor head 40 through the slit 45 to be filled.

  Further, although the ring-shaped fixing plate portion is illustrated as an example, the fixing plate portion may have a rectangular shape or a polygonal shape such as a hexagonal shape or an octagonal shape. In this case, the length corresponding to the length L of the outer diameter of the fixing plate portion is a polygonal long side distance (distance farthest from the end face) that is an effective width (length) as the fixing plate. Any length L may be used.

  Further, the wedge portion 43 is formed with ribs 46 that protrude from the hollow frustoconical (cup-shaped) outer surface and bite into the concrete portion of the PC structure A, and in the vicinity of the end of the wedge portion 43. A ring-shaped locking groove 47 that locks the locking protrusion 27 of the trumpet sheath 22 is formed on the inner peripheral surface of the trumpet sheath 22.

  Since the ring-shaped locking groove 47 and the hemispherical locking protrusion 27 are engaged in this way, the trumpet sheath 22 is engaged with the fixing tool 4 by hanging the trumpet sheath 22 over the fixing tool 4. The trumpet sheath 22 is rotatable in the stopped state. For this reason, it is possible to adjust the position of the grout outlet 24 in a state where the trumpet sheath 22 does not fall out, and the workability is extremely good.

(Spiral muscle)
As shown in FIG. 1, the spiral muscle 5 according to the present embodiment has a spiral winding diameter of a predetermined outer diameter G and a rod diameter of the deformed steel rod from one deformed steel rod of SD295A (D13 or D16). After double winding at a pitch equivalent to (rebar diameter), the outer peripheral surfaces of the reinforcing bars that are spirally adjacent to each other with a predetermined outer diameter G and a predetermined pitch p are bent and molded. Here, double winding refers to the fact that the outer peripheral surfaces of adjacent spiral shaped deformed steel bars (rebars) are bent or close so that they contact or substantially contact each other over two or more rounds. And In this embodiment, the pitch p is 50 mm.

  The winding outer diameter G of the spiral muscle 5 according to the present embodiment is 200 mm or 240 mm, which is about 1.45 times the outer diameter L (138 mm or 166 mm) of the fixing plate portion 42. For this reason, the spiral streak 5 is located further outside the bolt groove 44 of the fixing plate portion 42 and in the immediate vicinity of the fixing plate portion 42, and the concrete is pressed into the PC structure A by being pressed by the fixing plate portion 42. The spiral muscles 5 are arranged on the outer side. For this reason, it is considered that the spiral muscle 5 can effectively act against the split tensile stress caused by the wedge-shaped material being sunk and the surrounding concrete bulging outward.

  By the way, the winding outer diameter G of the spiral streak 5 according to the present embodiment is about 1.45 times the outer diameter L (138 mm or 166 mm) of the fixing plate portion 42. Since the spiral streak 5 only needs to be positioned further outward than 44 and in the immediate vicinity of the fixing plate portion 42, the winding outer diameter of the spiral streak according to the present invention is 1.3 times the outer diameter or long side distance of the fixing plate portion. It is thought that it may be 1.5 times or less.

  In addition, as described above, the spiral muscle 5 can be arranged without interfering with the bolt groove 44 or the anchor for fixing the fixing tool main body 41 by making the winding diameter of the spiral muscle 5 larger than usual. became. For this reason, in the fixing tool reinforcing structure 1 according to the present embodiment, the spiral streaks 5 are arranged at a close distance of the fixing plate portion 42. Thereby, the fixing tool reinforcement structure 1 can effectively counter the splitting tensile stress.

[Function and effect of fixing tool reinforcement structure 1]
According to the fixing device reinforcing structure 1 according to the embodiment described above, the double winding portion of the spiral muscle can effectively counter the splitting stress that increases near the outer surface, and the remaining portion is a normal spiral muscle. Therefore, it is possible to prevent excess reinforcing bars, to reduce the risk of placement failure, and to exhibit excellent toughness.

  Further, according to the fixing tool reinforcing structure 1 according to the embodiment, the winding outer diameter G of the spiral reinforcement 5 is larger than that of the fixing plate portion 42, so that the range of concrete that can be restrained by the spiral reinforcement 5 is increased. Brittle fracture can be effectively prevented.

  In addition, according to the fixing tool reinforcing structure 1 according to the embodiment, since the spiral streaks 5 are arranged on the outer side and the nearest side of the fixing tool 4, the fixing tool 4 is recessed inside the PC structure A and surroundings. It is possible to effectively counter the splitting tensile stress caused by the outward expansion of the concrete.

[Effect confirmation experiment]
Next, an effect confirmation experiment performed for confirming the effect of the present invention will be described. In this experiment, as shown in Table 1, two types of fixing devices of different sizes and two types of spiral muscles corresponding to the two types of fixing devices were prepared, and a total of four specimens were prepared. A load corresponding to the size was loaded and the cracking state was visually observed, and the amount of the fixing tool embedded in the specimen was measured.

  The type 1 fixing tool has an outer diameter L of the fixing plate portion of 138 mm and the entire length of the fixing tool body is 145 mm. The type 2 fixing tool has an outer diameter L of the fixing plate portion of 166 mm and the fixing tool. The total length of the main body is 160 mm.

  The spiral muscles (1) and (3) are assumed to be conventional spiral muscles, and the spiral muscle (1) is a spiral muscle obtained by winding a deformed steel rod of D13 four times at a pitch of 50 mm, (3) is a spiral bar formed by winding a deformed steel bar of D16 five times at a pitch of 50 mm.

  The spiral bars (2) and (4) are spiral bars according to the above-described embodiment of the present invention, and the spiral bar (2) is obtained by double winding the deformed steel bar of D13 as described above. The spiral rebar is wound four times at a pitch of 50 mm, and the spiral rebar (4) is a spiral rebar wound twice with a D16 deformed steel bar at a pitch of 50 mm.

  The shape of the test body was a vertically long rectangular parallelepiped shape, and the cover thickness between the spiral streak and the surrounding four surfaces was uniformly 10 mm.

  Fig. 8 is a photograph comparing the cracks of a specimen with a type 1 fixing tool embedded in spiral streaks (1) and (2). The maximum crack width was measured at the part that was considered to be the largest by visual observation. It is. FIG. 9 is a comparison of the specimens with the type 2 fixing tool embedded in spiral muscles (3) and (4). FIG. 10 is a graph showing the amount of penetration of a test body in which a type 1 fixing tool is embedded, and FIG. 11 is a test body in which a type 2 fixing tool is embedded.

  As is apparent from FIGS. 8 to 11, the specimen using the spiral muscles (2) and (4) according to the embodiment of the present invention is not harmful although cracking occurs, and the amount of penetration is 1.0 mm. It is as follows. This is because the winding diameter of the spiral streaks is 1.45 times the diameter of the fixing tool as described above, so that it is larger than the locking claw that is the fixing tool attachment, completely covering the fixing tool, and the bearing surface It is thought that the fact that the spiral muscles can be arranged closer to a closer position is a factor that can counter the splitting stress.

  On the other hand, the specimen using the spiral muscle (1) has a maximum crack width of 2.00 mm and a maximum penetration amount of 2.53 mm, which is about to break. In addition, the specimen using the spiral muscle (3) has a maximum penetration amount of 4.11 mm, which clearly leads to split fracture. This is thought to be due to the lack of reinforcing bars that suppress the development of cracks that occur on the surface of the specimen.

  Thus, this experiment has proved that it is possible to effectively counter the splitting stress by making the surface side of the PC structure double wound like the spiral muscle according to the present invention. Further, since the reinforcing bars are only spiral bars, it is easy to pour the concrete from the surroundings in the double winding part, and it can be said that there is little risk of poor placement.

  Moreover, in this experiment, in order to estimate the stress borne by the spiral muscle, a strain gauge was attached to the spiral muscle and measured. S-1 and S-2 are the measurement results of the gauge attached to the third stage (third round) from the upper stage of the spiral line, and S-3 and S-4 are attached to the uppermost stage (double winding part) of the spiral line. It is the measurement result of the gauge.

  12 and 13, it can be seen that the rebar at the uppermost double-winding portion has yielded near the final load (the ultimate load), while the third-stage rebar has a surplus. In other words, even if the rebar is double-rolled, it yields at that part, and according to this experiment, the vicinity of the outer surface around the fixing tool where the spiral rebar is double-rolled is a place where split tensile stress is concentrated. It can be said that it was confirmed. Therefore, as in the present invention, in a pre-stressed PC structure, the spiral muscles that are concentrated in the vicinity of the surface, which is a portion where the load of the split tensile stress is high, are concentrated against the split tensile stress. It is effective.

[Fixing device reinforcement method]
Next, a fixing tool reinforcing method according to an embodiment of the present invention will be described with reference to FIG. Since the above-described fixing tool reinforcing structure 1 is constructed by the fixing tool reinforcing method according to the present embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

(Fixing tool installation process)
In the fixing tool reinforcement method according to the present embodiment, as shown in FIG. 14, first, a fixing tool installation step of setting the above-described fixing tool 4 on a concrete mold is performed. The fixing tool 4 is installed in the mold by fixing the fixing tool 4 to the mold using the bolt groove 44.

(Spiral muscle installation process)
Next, in the fixing tool reinforcing method according to the present embodiment, a spiral streak installation step of installing the spiral streaks 5 around the fixing tool 4 is performed. In order to prevent the fixing tool from entering the concrete structure, which is the main factor of split fracture, the minimum is near the back surface (opposite surface of the outer surface) of the anchor head 40 that is the bearing surface, that is, the outer surface of the PC structure. It is preferable to take the cover thickness and arrange the spiral streaks 5 close to the fixing plate portion 42. In this step, the distance between the circumscribed surface of the double winding portion of the spiral streaks 5 and the outer surface of the PC structure A is as follows. Install so that it is 10 mm evenly and accurately.

  At this time, as described above, the winding outer diameter G of the spiral streak 5 is larger than the outer diameter L of the fixing plate portion 42 and is 1.45 times the outer diameter L of the fixing plate portion 42, that is, G≈1. .45 × L, so that the spiral streaks 5 cover the periphery of the fixing plate portion 42 without interfering with the bolt groove 44 of the fixing plate portion 42 or its fixing tool. The spiral streaks 5 can be disposed close to the fixing plate portion 42. However, if 1.3 L ≦ G ≦ 1.5 L, the spiral streaks 5 cover the periphery of the fixing plate portion 42 without interfering with the bolt groove 44 of the fixing plate portion 42 and the fastening tool thereof, and spiral. It is considered that the streak 5 can be disposed in the vicinity of the fixing plate portion 42.

(Sheath connection process)
Next, in the fixing tool reinforcing method according to the present embodiment, a sheath connection step of connecting the sheath 2 such as the spiral sheath 20, the joint sheath 21, and the trumpet sheath 22 to the fixing tool 4 is performed. In this step, the locking projection 27 is engaged with the locking groove 47 of the fixing tool 4 to lock the trumpet sheath 22 to the fixing tool 4.

  At this time, the bead 25 of the trumpet sheath 22 abuts on the tube end of the fixing tool 4, so that the angle is corrected and corrected even if the fitting angle between the fixing tool 4 and the trumpet sheath 22 is shifted. At the same time, the locking protrusion 27 is fitted into the locking groove 47 and the trumpet sheath 22 is hooked and fixed, so that the connection of the trumpet sheath 22 to the fixing device 4 is extremely easy and reliable.

  In addition, since the trumpet sheath 22 can be rotated in a state where the locking projection 27 is locked in the locking groove 47, the position of the grout outlet 24 of the trumpet sheath 22 without the trumpet sheath 22 falling off. Therefore, workability is extremely good.

  Thereafter, the joint sheath 21 and the spiral sheath 20 are connected to the trumpet sheath 22. At this time, the bead 26 of the trumpet sheath 22 is fixed by being brought into contact with the tube end of the joint sheath 21, so that the joint sheath 21 and the spiral sheath 20 can be easily connected to the trumpet sheath 22.

(Concrete placing process)
Next, in the fixing tool reinforcing method according to the present embodiment, a concrete placing process is performed in which concrete is placed around the fixing tool 4 and the spiral streaks 5. In this step, concrete according to the design strength is placed using a vibration device such as a vibrator so as not to form a cavity. At this time, as described above, the spiral muscle 5 has a double winding portion, but the pitch of the general portion of the spiral continuous with the double winding portion is 50 mm. Since it can fully wrap around the double winding part, there is little risk of poor placement such as junkers.

  The fixing tool reinforcing method process according to the present embodiment described above is common only in the difference between the case where the PC structure is precast and the case where the PC structure is made on site, or whether it is performed on site. However, the present invention is applicable.

  After that, the tension material 3 is inserted into the sheath 2, and the tension material 3 is tensioned with a tension jack such as a hole jack and fixed with the anchor head 40. After a predetermined strength of the concrete is developed, the concrete structure is formed by a post tension method. If prestress is introduced into the PC structure, the PC structure is completed.

  As mentioned above, although the fixing tool reinforcement structure and the fixing tool reinforcement method according to the embodiment of the present invention have been described in detail, each of the above-described or illustrated embodiments shows one embodiment embodied in carrying out the present invention. These are merely examples, and the technical scope of the present invention should not be construed in a limited manner.

  In particular, the size of the fixing tool, the tube diameter of the sheath, the winding diameter of the spiral muscle, and the like can be appropriately changed according to the size of the PC structure and the thickness of the binding material according to the necessary prestress. Further, the precast PC structure has been described as an example, but it is clear that the post-tension method can be applied to a PC structure that is made in the field.

1: Fixing device reinforcement structure 2: Sheath 20: Spiral sheath (sheath)
21: Joint sheath (sheath)
22: Trumpet sheath (sheath)
23: Tubular body (trumpet sheath)
24: Grout outlet (trumpet sheath)
25, 26: Bead (trumpet sheath)
27: Locking protrusion (trumpet sheath)
3: Tensile material 4: Fixing tool 40: Anchor head 41: Fixing tool body 42: Fixing plate portion L: Outer diameter of fixing plate portion 43: Wedge portion 44: Groove 45 for bolt: Slit 46: Rib (rib)
47: Locking groove 5: Spiral muscle G: Spiral muscle outer diameter p: Spiral muscle pitch A: PC structure

Claims (4)

A fixing member reinforcing structure for resisting split tensile stress acting around a fixing member of a PC structure,
A spiral spiral line is arranged so as to surround the fixing device,
This spiral rebar is double-wrapped from one rebar so that the outer surface side of the outer surface side is in contact with the outer peripheral surface of the spiral adjacent rebars over two or more turns. A fixing member reinforcing structure characterized in that the portion is formed such that the outer peripheral surfaces of adjacent spiral reinforcing bars are separated from each other. The fixing member reinforcing structure according to claim 1, wherein a winding outer diameter of the spiral line is larger than a maximum distance between ends of the fixing plate of the fixing device. The fixing tool according to claim 2, wherein the winding outer diameter of the spiral stirrer is not less than 1.3 times and not more than 1.5 times the outer diameter or long side distance of the fixing plate of the fixing tool. Reinforced structure. A fixing device reinforcing method for reinforcing a PC structure to counteract split tensile stress acting around a fixing device,
From one reinforcing bar, the vicinity of the end on the outer surface side was double-wound so that the outer peripheral surfaces of adjacent spiral reinforcing bars contact each other over two or more rounds, and the remaining part was spiral. A fixing tool reinforcing method, comprising: a spiral bar installation step of installing spiral bars formed so that outer peripheral surfaces of adjacent reinforcing bars are separated from each other so as to surround the fixing tool.