Resin injection anchor and method for reinforcing concrete structure using the same

Abstract

To provide a resin injection anchor capable of preventing falling off during construction in reinforcement construction of a concrete structure, and a reinforcing method for a concrete structure using the anchor.SOLUTION: A resin injection anchor body 10a comprises: a rod part 11 inserted into a lower hole formed in a concrete structure, and having a plurality of tapered parts 15a to 15e each having a tip part 11a side smaller than the diameter of the lower hole and a root part 13a side larger than the diameter of the lower hole, in which the diameter of the root part 13a side of each of the tapered parts 15a to 15e is gradually increased toward the root part 13a side of the rod part 11; a plate-like part 12 which is in contact with a net reinforcement to indicate a reference surface of the cover thickness of a coating layer; a head part 13 having an injector connection part 18 for connecting an injector for injecting synthetic resin; and an injection hole 14 which penetrates axially from the head part 13 to the tip end part 11a of the rod part 11.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to the reinforcement of concrete structures such as bridges, and in particular, to a resin injection anchor used together with a reinforcement jig for reinforcing existing structures by newly adding reinforcing bars in addition to repairing cracked bridge decks and wall bodies, and a method for reinforcing concrete structures using the same.

Background Art

[0002] In a road bridge constructed by a concrete structure, since it repeatedly receives dynamic loads due to the passage of vehicles, the load on the bridge deck among the main members of the road bridge is quite large. And when the repeated excessive load or impact load is large compared to the strength of the bridge itself or when the service life is greatly exceeded, cracks occur on the lower surface of the deck, and these cracks gradually become a fine network running vertically and horizontally on the lower surface, leading to the peeling of concrete and the like.

[0003] The occurrence of such cracks causes corrosion and breakage of the reinforcing bars in the concrete. Therefore, in normal cases, it is preferably to repair the deck at the initial stage when cracks occur. As the repair construction of this deck, conventionally, a resin injection method of injecting an epoxy resin or the like into the cracks, and a cross-section repair method of repairing the cavity part and the concrete peeling part generated on the deck with cement mortar have been performed.

[0004] However, most of these construction methods are mainly aimed at repairing damaged parts, and although they are effective in preventing the progress of corrosion of reinforcing bars and the like, they cannot cope with the construction of increasing the strength of the structure itself. On the other hand, the applicant of the present application has developed a reinforcement jig for suitable repair and reinforcement of existing concrete structures including bridges (see, for example, Patent Document 1).

[0005] This reinforcing jig comprises a head portion that restrains two intersecting reinforcing bars in a fixed direction, a rod portion that protrudes from the head portion in the axial direction thereof and is screwed into a hole drilled in a concrete structure, and a tapered portion formed on the peripheral surface between the rod portion and the head portion, the insertion direction of which is tapered. The rod portion has two threads, namely, a first thread that acts as a cone cutting into the inner surface of the hole and a second thread that is formed to have a lower height than the first thread and acts as a guide during screwing.

[0006] In the reinforcing construction method using this reinforcing jig, a reinforcing mesh in which a plurality of reinforcing bars are arranged to intersect substantially in a lattice pattern is disposed on the surface of an existing concrete structure, a plurality of holes are drilled corresponding to positions where the peripheral surface of the tapered portion of the reinforcing jig abuts against both of two intersecting reinforcing bars, the rod portions of the plurality of reinforcing jigs are screwed into the respective holes, and the reinforcing jig is connected to the concrete structure side by the restraining force received by the tapered portion of the reinforcing jig from the two intersecting reinforcing bars and the restraining force received by the rod portion of the reinforcing jig from the inner surface of the hole, thereby fixing the reinforcing mesh to the surface of the concrete structure, and covering the reinforcing mesh and the reinforcing jig with a coating layer.

[0007] Also, as the reinforcing jig, a female thread portion as an injection tool connection portion for connecting an injection tool made of synthetic resin is used, and an injection hole having a uniform inner diameter that penetrates in the axial direction is provided by aligning the female thread portion, a hexagonal hole, and the head portion. After applying an intermediate coating material that constitutes the coating layer, the injection tool is screwed into the female thread portion, and for example, an epoxy resin is injected as a synthetic resin from this injection tool, so that cracks and gaps generated in the concrete structure are filled with the epoxy resin, and not only the repair but also the reinforcing strength can be made sufficiently high.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] By the way, when using a reinforcing jig provided with an injection hole for injecting an epoxy resin as described above, and injecting the epoxy resin at a position other than the position where the tapered portion of the reinforcing jig receives the restraining force from two intersecting reinforcing bars of the mesh reinforcing bars, the reinforcing jig is connected to the concrete structure side only by the restraining force received by its rod portion from the inner surface of the lower hole. Therefore, when constructing a road bridge without traffic control, the reinforcing jig may fall off from the lower hole during construction due to vibrations generated by passing vehicles or the like.

[0010] Therefore, an object of the present invention is to provide an anchor for resin injection capable of preventing dropping during construction in the reinforcement construction of a concrete structure, and a method for reinforcing a concrete structure using the same.

Means for Solving the Problems

[0011] The anchor for resin injection of the present invention is an anchor for resin injection used in a method for reinforcing a concrete structure in which lattice-shaped mesh reinforcing bars are fixed along the surface of the concrete structure and the mesh reinforcing bars are covered with a covering layer. It is a rod portion inserted into a lower hole formed in the concrete structure, and has a plurality of tapered portions having a tapered shape in which the tip end side of each is thinner than the diameter of the lower hole and the base end side is thicker than the diameter of the lower hole. A rod portion in which the diameter on the base end side of each tapered portion gradually becomes thicker as it goes toward the base end side of the rod portion, a plate-like portion that indicates a reference surface for the cover thickness of the covering layer by contacting the mesh reinforcing bars, a head portion having an injection tool connection portion for connecting an injection tool for injecting a synthetic resin, and an injection hole that penetrates in the axial direction from the head portion to the tip end portion of the rod portion.

[0012] The method for reinforcing a concrete structure using the resin injection anchor of the present invention includes fixing lattice-shaped reinforcing bars along the surface of the concrete structure, drilling a hole in the concrete structure corresponding to the position where the plate-shaped portion of the resin injection anchor abuts against the reinforcing bars, inserting the rod portion of the resin injection anchor into the hole so that the plate-shaped portion abuts against the reinforcing bars, covering the reinforcing bars with a coating layer, and connecting an injection device to the injection device connection portion of the resin injection anchor to inject a synthetic resin.

[0013] According to the resin injection anchor of the present invention, the rod portion inserted into the hole has a plurality of tapered portions in a tapered shape where each tip end side is thinner than the diameter of the hole and the root end side is thicker than the diameter of the hole. Since the diameter of the root end side of each tapered portion gradually becomes thicker as it goes toward the root end side of the rod portion, when inserting the rod portion into the hole, it can be smoothly inserted from the tip end side of each tapered portion that is thinner than the diameter of the hole, and is fixed in the hole by the root end of each tapered portion that is thicker than the diameter of the hole. Then, the reinforcing bars are covered with a coating layer, and an injection device is connected to the injection device connection portion of the resin injection anchor to inject a synthetic resin. Since the diameter of the root end side of each tapered portion of the rod portion inserted into the hole becomes thicker as it goes toward the root end side of the rod portion, the root end side of each tapered portion is caught and held by the inner wall of the hole, so that the resin injection anchor can be prevented from falling off.

[0014] It is desirable that the peripheral wall portion of the rod portion has a slit formed therethrough to the injection hole. Thereby, the synthetic resin injected into the injection hole from the injection device connected to the injection device connection portion flows not only into the tip end portion of the rod portion but also into the concrete structure through the slit formed in the peripheral wall portion of the rod portion.

[0015] The resin injection anchor of the present invention preferably has an index indicating the covering thickness from the reference surface on the outer peripheral surface of the head portion. Thereby, after inserting the rod portion of the resin injection anchor into the lower hole so that the plate-like portion abuts against the mesh reinforcing bar, when covering the mesh reinforcing bar with the covering layer, the covering thickness from the reference surface of the head portion of this resin injection anchor is used as a mark. , the covering layer can be formed.

[0016] The head portion preferably has a fragile portion for making it easy to break when removing the injection device. Thereby, after injecting the synthetic resin from the injection device connected to the injection device connection portion, when removing the injection device from the injection device connection portion, the head portion breaks from the fragile portion and can be removed together with the injection device.

[0017] The resin injection anchor of the present invention is a hollow cylindrical extension member that extends the head portion, and includes an extension member having an injection device connection portion for connecting an injection device for injecting synthetic resin. The head portion preferably has a fitting portion for fitting the extension member. Thereby, when the covering thickness of the covering layer is thick and the length of the head portion is insufficient, by fitting the extension member to the fitting portion of the head portion, the injection device is connected to the injection device connection portion of this extension member, and the synthetic resin can be injected.

[0018] The resin injection anchor of the present invention is a cap member that covers the head portion, and preferably includes a cap member having an index indicating the covering thickness from the reference surface on its outer peripheral surface. Thereby, after inserting the rod portion of the resin injection anchor into the lower hole so that the plate-like portion abuts against the mesh reinforcing bar, the mesh reinforcing bar is covered with the covering layer with the head portion covered with the cap member. At this time, the covering layer can be formed using the index indicating the covering thickness from the reference surface of the outer peripheral surface of the cap member as a mark. Further, by removing the cap member after covering, the injection device connection portion of the head portion is exposed, so that an injection device can be connected to this exposed injection device connection portion to inject synthetic resin.

[0019] Further, it is desirable that the outer peripheral surface of the cap member has a convex portion. Thereby, when removing the cap member by pinching it with a finger, the finger catches on the convex portion of the outer peripheral surface of the cap member, so that it can be easily removed.

Advantages of the Invention

[0020] (1) According to the resin injection anchor having a rod portion inserted into a lower hole formed in a concrete structure, the rod portion having a plurality of tapered portions with a tapered shape in which the tip end portion side is thinner than the diameter of the lower hole and the root portion side is thicker than the diameter of the lower hole, and the diameter of the root portion side of each tapered portion gradually increases toward the root portion side of the rod portion, a plate-like portion indicating a reference surface of the cover thickness by contacting the wire reinforcement, a head portion having an injection tool connection portion for connecting an injection tool for injecting synthetic resin, and an injection hole penetrating in the axial direction from the head portion to the tip end portion of the rod portion, when inserting the rod portion into the lower hole, it can be smoothly inserted from the tip end portion side of each tapered portion thinner than the diameter of the lower hole, and when injecting synthetic resin, since the root portion side of each tapered portion is caught and held by the inner wall of the lower hole, it is possible to prevent the resin injection anchor from falling off and perform resin injection, and perform reinforcement construction of the concrete structure.

[0021] (2) By having a slit formed through the peripheral wall portion of the rod portion to the injection hole, the synthetic resin injected into the injection hole from the injection tool connected to the injection tool connection portion can easily flow into the concrete structure not only through the tip end portion of the rod portion but also through the slit formed in the peripheral wall portion of the rod portion, and is efficiently filled into the cracks in the concrete structure.

[0022] (3) By having an index indicating the cover thickness from the reference surface on the outer peripheral surface of the head portion, it is possible to form a cover layer using the index indicating the cover thickness from the reference surface of the head portion of the resin injection anchor as a mark, and it is possible to easily and surely secure a predetermined cover thickness of the cover layer.

[0023] (4) The head part has a weak part to make it easy to break when removing the injection device. When removing the injection device from the injection device connection part, the head part breaks from the weak part and can be removed together with the injection device, making the removal work easier.

[0024] (5) It includes an extension member that is a hollow cylindrical member extending the head part and has an injection device connection part for connecting an injection device for injecting synthetic resin. The head part has a fitting part for fitting the extension member. When the length of the head part is insufficient, the extension member can be fitted to the fitting part of the head part to inject synthetic resin, and it is possible to cope even when the covering layer has a thick overlapping thickness.

[0025] (6) It includes a cap member that covers the head part and has an index indicating the overlapping thickness from a reference surface on its outer peripheral surface. By removing the cap member after covering, the injection device connection part of the head part is exposed, and an injection device can be connected to easily inject synthetic resin, improving workability. Also, the covering layer can be formed using the index indicating the overlapping thickness from the reference surface of the outer peripheral surface of the cap member as a mark, and it is possible to easily and surely ensure a predetermined overlapping thickness of the covering layer.

[0026] (7) Since the outer peripheral surface of the cap member has a convex part, when removing the cap member by pinching it with a finger, the finger catches on the convex part of the outer peripheral surface of the cap member, making it possible to easily remove it.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0028] FIG. 1 is a schematic view showing an example of reinforcing the floor slab of a bridge by the concrete structure reinforcement method in the embodiment of the present invention. FIG. 2 is a view taken in the direction of the arrow along line A-A of FIG. 1, which is a bottom view showing the arrangement of the welded wire fabric, the reinforcing anchor, and the anchor for resin injection. FIG. 3 is a sectional view of the main part showing the state where the anchor pin is screwed into the anchor hole to fix the steel bar.

[0029] In FIG. 1, the concrete structure is such that ground covers 2 are integrally formed at both ends in the road width direction, and a bridge deck slab 1 with reinforcing bars arranged in a slab shape inside is supported by bridge girders 3. The deck slab 1 is an existing one, and cracks have occurred on the surface of its lower surface due to repeated dynamic loads from passing vehicles V. In the method for reinforcing the concrete structure in this embodiment, in order to reinforce the deck slab 1, a mesh reinforcement 4 in which vertical and horizontal reinforcing bars 4a and 4b are integrally welded in a lattice shape as shown in FIG. 2 is fixedly held by anchor pins 5 as the reinforcing anchors in this embodiment.

[0030] As shown in FIG. 3, the anchor pin 5 has a head portion 5a with its end face formed in a gentle arc shape at the lower end, and a rod portion 5b extending from the head portion 5a toward the upper end. On the lower end side of the rod portion 5b, a tapered portion 5c with a tapered outer shape from the head portion 5a toward the upper end side, that is, in the screwing progress direction, is formed. Further, on the head portion 5a side of the anchor pin 5, there is a hexagonal hole 5d as a polygonal cross-section hole for fitting and rotating a rotary tool.

[0031] Also, on the outer peripheral surface of the rod portion 5b on the tip side of the tapered portion 5c, two threads 5g and 5h are formed. The thread 5g is a triangular thread with a triangular cross-sectional shape, and acts as a cone that cuts into the inner surface of an anchor hole 1b described later (hereinafter, this thread 5g is referred to as a "cone thread"). The thread 5h is a trapezoidal thread or a square thread formed with a lower height than the cone thread 5g, and acts as a guide during screwing (hereinafter, this thread 5h is referred to as a "guide thread").

[0032] As shown in Fig. 2, the anchor pins 5 are screwed into the floor slab 1 respectively corresponding to the intersections of the longitudinal and transverse reinforcing bars 4a and 4b. That is, the anchor pins 5 are screwed into the corner portions where the reinforcing bars 4a and 4b intersect in a cross shape, and at such positions that the peripheral surface of the rod portion 5b comes into contact with these reinforcing bars 4a and 4b simultaneously. When the anchor pins 5 are screwed into the floor slab 1, as shown in Fig. 3, the tapered portion 5c comes into contact with the peripheral surface of the reinforcing bars 4a and 4b, and when viewed from the placement center of the anchor pins 5, the outer radius becomes larger due to this tapered portion 5c. Therefore, the anchor pins 5 push the reinforcing bars 4a and 4b in the direction of the arrow in Fig. 2, and tensile forces act on these reinforcing bars 4a and 4b.

[0033] Since the anchor pins 5 are provided with the tapered portion 5c in this way, if the positions of the anchor pins 5 are appropriately set with respect to the lattice-shaped web reinforcing bars 4 shown in Fig. 2, a uniform tensile force can be applied in the direction having an angle of 45 degrees with the lattice from the center of the web reinforcing bars 4 as shown by the arrow in the figure. Therefore, when constructed with respect to the floor slab 1 as shown in Fig. 1, even if the floor slab 1 deflects and deforms, the web reinforcing bars 4 follow this deflection and deformation, and it is possible to prevent a gap from occurring between the anchor pins 5 and the reinforcing bars 4a and 4b.

[0034] After the construction of the web reinforcing bars 4, a coating layer 6 made of mortar resin or the like is constructed. In Fig. 1, its schematic is shown by a dashed line. Also, in the reinforcement method of the concrete structure in this embodiment, since synthetic resin is injected into the fine voids, cracks, etc. existing between the floor slab 1, the web reinforcing bars 4, and the coating layer 6, the resin injection anchor 10 is used.

[0035] Fig. 4 is a view showing the resin injection anchor body, where (a) is a plan view, (b) is a front view, (c) is a bottom view, (d) is a right side view, (e) is a sectional view taken along line B - B, and (f) is an enlarged view of part C. Fig. 5 is a view showing the cap member, where (a) is a plan view, (b) is a partial sectional view taken along line D - D, and (c) is a bottom view. Fig. 6 is a sectional view of the main part showing the state where the resin injection anchor body is inserted into the anchor hole.

[0036] The resin injection anchor 10 is composed of a resin injection anchor body 10a shown in Fig. 4 and a cap member 10b shown in Fig. 5. The resin injection anchor 10 is made of synthetic resin (plastic). The resin injection anchor body 10a has a rod portion 11 to be inserted into an anchor hole 1d as a dowel hole described later, a plate-like portion 12 to be brought into contact with the wire mesh 4 when inserted into the anchor hole 1d, and a head portion 13 to which an injection tool 8 (see Fig. 7) for synthetic resin is connected. Further, an injection hole 14 penetrating in the axial direction from the end portion 13a of the head portion 13 to the tip portion 11a of the rod portion 11 is formed in the resin injection anchor body 10a.

[0037] The diameter of the tip portion 11a of the rod portion 11 is smaller than the diameter of the anchor hole 1d, and the diameter of the root portion 11b is larger than the diameter of the anchor hole 1d. The rod portion 11 is composed of a plurality of tapered portions 15a, 15b, 15c, 15d, 15e having a tapered shape in which the tip portion 11a side is smaller than the diameter of the anchor hole 1d and the root portion 11b side is larger than the diameter of the anchor hole 1d, and cylindrical portions 16a, 16b, 16c, 16d, 16e provided on the root portion 11b side of each tapered portion 15a, 15b, 15c, 15d, 15e, respectively.

[0038] The diameter on the root portion 11b side of each of the tapered portions 15a to 15e gradually increases toward the root portion 11b side. Each of the cylindrical portions 16a to 16e has the same diameter as the diameter on the root portion 11b side of each of the tapered portions 15a to 15e. That is, the diameters of the cylindrical portions 16a to 16e also gradually increase toward the root portion 11b side. Note that the number of the tapered portions 15a to 15e and the cylindrical portions 16a to 16e is not limited.

[0039] Further, the peripheral wall portion of the rod portion 11 has a slit 17 that is long in the axial direction of the rod portion 11. The slit 17 is formed so as to penetrate to the injection hole 14. In the present embodiment, the slit 17 is formed from the middle of the tapered portion 15a to the middle of the tapered portion 15e. Two slits 17 are formed at intervals of 180° around the axis. Note that the length, interval, and number of the slits 17 are not limited.

[0040] The plate-like portion 12 is disc-shaped. The plate-like portion 12 is disposed between the rod portion 11 and the head portion 13. As shown in FIG. 6, when the rod portion 11 is inserted into the anchor hole 1d, the plate-like portion 12 abuts against the wire mesh 4, so that the surface on the rod portion 11 side indicates the reference surface 12a of the covering thickness of the covering layer 6 (see FIG. 10).

[0041] The head portion 13 has an injection tool connection portion 18 to which an injection tool 8 (see FIG. 7) for injecting synthetic resin is connected. On the outer peripheral surface of the head portion 13, groove portions 19a, 19b, 19c are formed as indicators showing the covering thickness from the reference surface 12a. For example, the groove portions 19a to 19c are formed at positions 10 mm, 15 mm, and 20 mm from the reference surface 12a, respectively. The groove portions 19a to 19c are grooves cut in a V shape at an angle of 90°, as shown in FIG. 4(f). The groove portions 19a to 19c also function as fragile portions to be easily broken when removing the injection tool. Further, the head portion 13 has a recess 20 as a fitting portion for fitting an extension member 9 (see FIG. 8) described later.

[0042] As shown in FIG. 6, the cap member 10b is for covering the head portion 13 so that the covering layer 6 does not flow into the injection hole 14 when the covering layer 6 is constructed with mortar resin or the like. The cap member 10b fits into the injection tool connection portion 18. As shown in FIG. 5, the cap member 10b is a bottomed cylindrical shape and is formed such that the inner diameter gradually decreases from the opening portion 23a toward the bottom portion 23b. Thereby, when the cap member 10b is fitted into the injection tool connection portion 18, the cap member 10b is prevented from falling off from the injection tool connection portion 18.

[0043] On the outer peripheral surface of the cap member 10b, a groove portion 21 is formed as an index indicating the covering thickness. The groove portion 21 indicates the covering thickness from the reference surface 12a in a state where the tip surface of the cap member 10b is in contact with the plate-like portion 12. For example, when the thickness of the plate-like portion 12 is 2 mm, by setting the position of the groove portion 21 from the tip surface of the cap member 10b to 8 mm, the groove portion 21 indicates a covering thickness of 10 mm. The groove portion 21 is a groove cut in a V shape at an angle of 90°, similar to the groove portions 19a to 19c described above.

[0044] Also, the outer peripheral surface of the cap member 10b has a convex portion 22. The convex portion 22 is a belt-shaped portion having a rectangular cross-section formed around the axis of the cap member 10b. The convex portion 22 is formed so that a finger gets caught when the cap member 10b is pinched with a finger.

[0045] The procedure for reinforcing the floor slab 1 with the wire mesh reinforcement 4 using the above anchor pins 5 and resin injection anchors 10 is as follows.

[0046] First, as shown in FIG. 9, a groove 1a is cut on the bottom surface of the floor slab 1. This groove 1a has a width of about 1.5 to 3 mm and a depth of about 5 to 10 mm, so that the injected synthetic resin can flow quickly, and it has a random arrangement including not only the longitudinal and transverse reinforcing bars 4a and 4b of the grid-shaped wire mesh reinforcement 4 but also diagonally running lines. The construction of such a groove 1a on-site can be relatively easily formed to a uniform depth by using a tool such as a sander.

[0047] Next, the wire mesh reinforcement 4 is temporarily positioned along the surface of the lower surface of the floor slab 1, and as described with reference to FIG. 3, the positions where the rod portion 5b of the anchor pin 5 can contact both of the reinforcing bars 4a and 4b are marked on the surface of the lower surface of the floor slab 1 using a centering rod or the like. At this time, a metal rod or the like having the same outer shape as the rod portion 5b can be used as the centering rod, and the number of anchor pins 5 to be constructed can be appropriately selected according to the size of the wire mesh reinforcement 4.

[0048] After marking the installation position of the anchor pin 5, while temporarily fixing the position of the mesh reinforcing bars 4 to the floor slab 1 with fixtures using the marking as a guide, drill an anchor hole 1b as a pilot hole as shown in Fig. 3 with a drill. The inner diameter of this anchor hole 1b shall be larger than the outer diameter of the rod portion 5b and smaller than the tapered thread 5g. Also, the depth of the anchor hole 1b shall be such that a slight gap 1c is formed at the tip when the resin injection anchor body 10a is inserted snugly.

[0049] After finishing the drilling operation of the anchor hole 1b, align the position of the mesh reinforcing bars 4 accurately again, adjust the positional relationship between the intersecting portions of the reinforcing bars 4a, 4b and the anchor hole 1b, and temporarily fix them along the bottom surface of the floor slab 1 again. Then, apply the tip of the rod portion 5b of the anchor pin 5 to the entrance of the anchor hole 1b, fit a rotary tool into the hexagonal hole 5d, and screw the anchor pin 5 into the floor slab 1 while rotating it. At this time, the tapered thread 5g of the anchor pin 5 advances while cutting into the inner surface of the anchor hole 1b, and the guiding thread 5h abuts against the inner surface of the anchor hole 1b to hold the posture of the anchor pin 5 so that its axis coincides with the axis of the anchor hole 1b.

[0050] When screwing the anchor pin 5 into the floor slab 1 while rotating it in this way, the tapered portion 5c comes into contact with the peripheral surfaces of the reinforcing bars 4a, 4b, and the anchor pin 5 is held by these reinforcing bars 4a, 4b. That is, as the anchor pin 5 is driven into the anchor hole 1b, the tapered portion 5c engages with the reinforcing bars 4a, 4b like a wedge, and two points on the peripheral surface of the tapered portion 5c are constrained by these reinforcing bars 4a, 4b. As a result, the rod portion 5b screwed into the anchor hole 1b receives a reaction force in the direction opposite to the direction of the arrow shown in Fig. 2, that is, in the direction of the acting force from the contact point with the reinforcing bars 4a, 4b, and is pressed against the inner surface of the anchor hole 1b in the direction in which this acting force acts.

[0051] Therefore, as shown in FIG. 3, when the head portion 5a abuts against the reinforcing bar 4a and the driving is completed, the taper portion 5c is constrained at two points by the reinforcing bars 4a and 4b, and the rod portion 5b is pressed by a force acting in the direction opposite to the arrow in FIG. 2 in the anchor hole 1b, and its peripheral surface is substantially in line contact with the inner peripheral surface of the anchor hole 1b. As a result, the anchor pin 5 is constrained at two points by the taper portion 5c and at one point by the rod portion 5b, and its peripheral surface is constrained at three points, and the anchor pin 5 is held in the state shown in FIG. 3 by the constraint at these three points.

[0052] In this way, the anchor pin 5 does not utilize the expansion deformation of the tip of the rod portion to apply an engaging force like a conventional concrete placing pin, but can be temporarily fixed by utilizing the restraining force on the taper portion 5c by the reinforcing bars 4a and 4b. Therefore, when the anchor pin 5 is constructed, no unnecessary internal stress is generated in the existing floor slab 1, and the construction pitch of the anchor pin 5 is also shortened.

[0053] Note that the rod portion 5b of the anchor pin 5 is held in contact with the inner peripheral surface of the anchor hole 1b, but only this portion is substantially in line contact, and a sufficient gap is maintained between the rod portion 5b and the anchor hole 1b, without any hindrance to the injection of the synthetic resin described later.

[0054] On the other hand, regarding the construction of the resin injection anchor 10, as shown in FIG. 6, positions where the rod portions 11 of the resin injection anchor main body 10a can contact both of the reinforcing bars 4a and 4b are marked on the surface of the lower surface of the floor slab 1 using a centering bar or the like. After marking the construction positions of the resin injection anchor main body 10a, the mesh reinforcing bars 4 are temporarily fixed in position on the floor slab 1 by a fixture, and the anchor holes 1d are drilled with a drill using the marking as a guide. The inner diameter of this anchor hole 1d is made slightly smaller than the outer diameter of the rod portion 11, and the drilling length is such that a gap 1e for injecting the synthetic resin described later is formed at the tip when the resin injection anchor main body 10a is inserted tightly.

[0055] After finishing the drilling work of the anchor hole 1d, the tip 11a of the rod portion 11 of the resin injection anchor body 10a is applied to the entrance of the anchor hole 1d and inserted by hitting it with a rubber hammer or the like. At this time, since the tip 11a side of each tapered portion 15a to 15d of the resin injection anchor body 10a is thinner than the diameter of the anchor hole 1d, it can be smoothly inserted into the anchor hole 1d. In particular, the resin injection anchor body 10a in the present embodiment is made of synthetic resin, and due to the gap of the slit 17 formed from the middle of the tapered portion 15a to the middle of the tapered portion 15e, each tapered portion 15a to 15d and each cylindrical portion 16a to 16d are elastically deformed and reduced in diameter, so that it smoothly progresses into the anchor hole 1d.

[0056] When the resin injection anchor body 10a is inserted into the anchor hole 1d of the floor slab 1 in this way, the plate-like portion 12 abuts against the reinforcing bar 4a. The resin injection anchor body 10a inserted into the anchor hole 1d is fixed in the anchor hole 1d by the base portions of each tapered portion 15a to 15d thicker than the diameter of the anchor hole 1d and each cylindrical portion 16a to 16d.

[0057] After inserting the resin injection anchor body 10a into the anchor hole 1d in the above manner, as shown in FIG. 6, the cap member 10b is attached to the injection tool connection portion 18. Alternatively, the resin injection anchor body 10a is inserted into the anchor hole 1d in a state where the cap member 10b is attached to the injection tool connection portion 18 in advance.

[0058] Next, the intermediate coating material 6b is thickened as shown in FIG. 6. This intermediate coating material 6b is applied by troweling or spraying. By using the groove portion 21 of the cap member 10b as a guide, the required covering thickness can be ensured for the thickness of the intermediate coating material 6b. At this time, it is preferable that the intermediate coating material 6b is sufficiently filled by troweling or spraying, but such a filling and thickening construction is difficult in terms of workability. On the other hand, in the construction of the present invention, even if a cavity is formed and remains as it is, the injection resin will be filled instead as described later, so there is no influence on the final construction.

[0059] In addition, when the covering thickness of the covering layer 6 is thick and the length of the head portion 13 is insufficient, the extension member 9 shown in FIG. 8 can be used. The extension member 9 is in the shape of a hollow cylinder and has an injection hole 90 penetrating in the axial direction. Further, the extension member 9 has a convex portion 91 as a fitting portion that fits into the concave portion 20 of the head portion 13 and an injection instrument connection portion 92 similar to the injection instrument connection portion 18 of the head portion 13. On the outer peripheral surface of the extension member 9, groove portions 93a, 93b, 93c are formed as indicators showing the covering thickness from the reference plane 12a in a state of being connected to the head portion 13. By connecting this extension member 9 to the head portion 13 of the resin injection anchor body 10a, it becomes possible to connect the injection instrument 8 to the injection instrument connection portion 92 of the extension member 9 and inject the synthetic resin.

[0060] After the thickening construction of the intermediate coating material 6b, the cap member 10b is removed from the injection instrument connection portion 18 of the resin injection anchor body 10a, and the injection instrument 8 is connected to the injection instrument connection portion 18 as shown in FIG. 7, and for example, an epoxy resin 7 is injected from the injection instrument 8 as a synthetic resin. The injection of the epoxy resin 7 can be performed for each resin injection anchor body 10a, but when the number is not so large, a plurality of hoses can be branched from the pressure feeding device of the epoxy resin 7 and connected to the injection instrument connection portions 18 of the respective resin injection anchor bodies 10a to perform the injection work simultaneously. In the case of this simultaneous work, the injection amount and injection pressure of the epoxy resin 7 from each resin injection anchor body 10a can be made uniform, which is very preferable in terms of construction.

[0061] The epoxy resin 7 supplied to the injection hole 14 blows out from the upper end of the injection hole 14 and is sent into the anchor hole 1d as shown in FIG. 7. In the anchor hole 1d, the epoxy resin 7 quickly flows downward due to gravity and injection pressure. Then, the epoxy resin 7 that has escaped from the anchor hole 1d flows into the groove 1a engraved on the lower side of the floor slab 1 and penetrates into the crack, and also flows so as to fill the gap between the surface of the lower surface of the floor slab 1 and the reinforcing bars 4a, 4b. The groove 1a has the same effect as the cross-cut method in which resin can be filled in cracks where free lime is generated.

[0062] That is, although the crack C (see Fig. 11) is covered with the intermediate coating material 6b, it has a cross-sectional shape that is cut open in the same way as the groove 1a. Therefore, the epoxy resin 7 from the groove 1a can flow due to the injection pressure and penetrate into the crack C. Also, at the part where the reinforcing bars 4a and 4b directly intersect the crack C, the epoxy resin 7 supplied along these reinforcing bars 4a and 4b directly enters the crack C. Therefore, even if the way the crack C occurs is irregular, the epoxy resin 7 can be filled into the crack C by utilizing the ribs of the reinforcing bars 4a and 4b and the randomly formed grooves 1a.

[0063] Note that after filling the epoxy resin 7, the injection tool 8 is removed from the resin injection anchor body 10a. At this time, since vulnerable parts are formed in the head part 13 of the resin injection anchor body 10a by the groove parts 19a, 19b, and 19c, the head part 13 is easily breakable, and the injection tool 8 is to be removed together with the injection tool connection part 18. Then, as shown in Fig. 10, the top coating material 6c is applied to the surface of the intermediate coating material 6b with a trowel, roller, or brush, and the coating layer 6 is formed by the intermediate coating material 6b and the top coating material 6c.

[0064] As described above, the epoxy resin 7 injected from the injection hole 14 of the resin injection anchor body 10a does not stay only in the anchor hole 1d, but can be distributed over a wide area of almost the entire floor slab 1 through the ribs of the reinforcing bars 4a and 4b and the randomly formed grooves 1a, and the anchor hole 1b into which the anchor pin 5 is screwed is also filled. Therefore, if a curing period is set after injecting an appropriate amount of the epoxy resin 7, the rod part 5b of the anchor pin 5 is firmly fixed in the anchor hole 1b by the solidification of the epoxy resin 7, and thereby the reinforcing mesh 4 can be stably held on the floor slab 1.

[0065] Also, since the solidified epoxy resin 7 remains as it is between the surface of the lower surface of the floor slab 1 and the reinforcing bars 4a and 4b, the surface of the lower surface of the floor slab 1 can be firmly covered, not only preventing the corrosion of the existing reinforcing bars in the floor slab 1, but also preventing the corrosion of the newly constructed reinforcing mesh 4 for reinforcement in the same way.

[0066] Furthermore, since the crack C is also filled with the epoxy resin 7, its growth can be suppressed even when subjected to an impact load or the like, and not only its repair but also the reinforcing strength can be made sufficiently high.

[0067] In the above example, the reinforcement construction of the bridge deck was described. However, it goes without saying that the surfaces such as the upper and lower surfaces and the side surfaces of various concrete structures may be used as the construction targets instead.

Industrial Applicability

[0068] The resin injection anchor of the present invention and the concrete structure reinforcement method using the same are useful for, for example, reinforcing concrete structures such as bridges, particularly for repairing cracked bridge decks and walls, and also for newly adding steel bars to existing structures for reinforcement.

Explanation of Signs

[0069] 1 Floor slab 1a Groove 1b, 1d Anchor hole 1c, 1e Gap 2 Ground covering 3 Bridge girder 4 Mesh reinforcement 4a, 4b Steel bar 5 Anchor pin 5a Head part 5b Rod part 5c Taper part 5d Hexagonal hole 5g, 5h Thread 6 Coating layer 6b Intermediate coating material 6c Top coating material 7 Epoxy resin 8 Injection device 9 Extension member 10 Resin injection anchor 10a Resin injection anchor body 10b Cap member 11 Rod part 11a Tip part 11b Root part 12 Plate-like part 12a Reference plane 13 Head part 13a Tip part 14, 90 Injection hole 15a, 15b, 15c, 15d, 15e Taper part 16a, 16b, 16c, 16d, 16e Cylindrical part 17 Slit 18, 92 Injection instrument connection part 19a, 19b, 19c, 93a, 93b, 93c Groove part 20 Recess 21 Groove part 22 Protrusion 23a Opening 23b Bottom 91 Protrusion

Claims

1. A resin injection anchor used in a method for reinforcing a concrete structure, which method involves fixing lattice-shaped wire reinforcement along the surface of the concrete structure and covering the wire reinforcement with a covering layer, the resin injection anchor comprising: a rod portion inserted into a hole formed in the concrete structure, the rod portion having a plurality of tapered portions that are tapered, with each tip end side being thinner than the diameter of the hole and each root end side being thicker than the diameter of the hole, and the diameter of the root end side of each tapered portion gradually increasing toward the root end side of the rod portion; a plate-shaped portion that abuts against the wire reinforcement and indicates a reference plane for the cover thickness of the covering layer; a head portion having an injection tool connection portion for connecting an injection tool for injecting synthetic resin; and an injection hole that axially penetrates from the head portion to the tip end portion of the rod portion. A resin injection anchor having the above components.

2. The resin injection anchor according to claim 1, wherein the peripheral wall portion of the rod portion has a slit formed therethrough to the injection hole.

3. The resin injection anchor according to claim 1, wherein the outer peripheral surface of the head portion has an indicator indicating the cover thickness from the reference plane.

4. The resin injection anchor according to claim 1, wherein the head portion has a weak portion for facilitating breakage when removing the injection tool.

5. The resin injection anchor according to claim 1, further including a hollow cylindrical extension member that extends the head portion and has an injection tool connection portion for connecting an injection tool for injecting synthetic resin, and wherein the head portion has a fitting portion for fitting the extension member.

6. The resin injection anchor according to claim 1, further including a cap member that covers the head portion, and the outer peripheral surface of the cap member has an indicator indicating the cover thickness from the reference plane.

7. The resin injection anchor according to claim 6, wherein the outer peripheral surface of the cap member has a convex portion.

8. A method for reinforcing a concrete structure using the resin injection anchor according to any one of claims 1 to 7, the method comprising: fixing lattice-shaped wire reinforcement along the surface of the concrete structure; drilling a hole in the concrete structure corresponding to a position where the plate-shaped portion of the resin injection anchor abuts against the wire reinforcement; inserting the rod portion of the resin injection anchor into the hole such that the plate-shaped portion abuts against the wire reinforcement; covering the wire reinforcement with the covering layer. Connecting the injection device to the injection device connection part of the resin injection anchor and injecting the synthetic resin A method for reinforcing a concrete structure including this.

Images