Precast concrete slab, joint structure for precast concrete slab, and method for joining precast concrete slabs

Abstract

To provide a precast concrete floor slab that can be joined in a short construction period. [Solution] A precast concrete slab having a concave joint at one end and a convex joint at the other end, wherein the concave joint has a plurality of grooves on the upper surface of the precast concrete slab that are perpendicular to the end face of the one end and continuous laterally with respect to the end face of the one end, and the convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other end of the precast concrete slab and are parallel to the end face of the other end in a continuous laterally direction, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars, wherein the grooves of the concave joint do not penetrate to the lower surface of the precast concrete slab and can accommodate the protruding reinforcing bars and convex-side anchoring plates corresponding to each of the grooves.

Description

Technical Field

[0001] The present invention relates to a precast concrete floor slab used as a floor slab when constructing highways, bridges, etc. In particular, it relates to a precast concrete floor slab used by joining when constructing a floor slab, a joining structure of the precast concrete floor slab, and a joining method of the precast concrete floor slab.

Background Art

[0002] When constructing highways, bridges, etc., precast concrete floor slabs are widely used as floor slabs. A plurality of precast concrete floor slabs are laid side by side between main girders, and adjacent floor slabs in the bridge axis direction are joined by a joint.

[0003] As such joining structures of precast concrete floor slabs, various ones are known as follows.

[0004] Patent Document 1 discloses a method in which a reinforcing bar is looped out from the end of a precast concrete floor slab, the reinforcing bars are lapped, and then a reinforcing bar is arranged, and then concrete as a filling material is placed to integrate them. Patent Document 2 discloses a method in which a reinforcing bar provided with a fixing body such as a nut or a crimping grip at the end of the reinforcing bar is lapped from the end of a precast concrete floor slab, a reinforcing bar is arranged, and then concrete as a filling material is placed to integrate them. In this method, the shear force transmission is improved by the unevenness provided at the end of the floor slab. Patent Document 3 discloses a method in which a reinforcing bar is taken out from the end of a precast concrete floor slab and lapped, and high-strength fiber-reinforced concrete is placed as a filling material without arranging a reinforcing bar to integrate them. Also in this method, the shear force transmission is improved by the unevenness provided at the end of the precast concrete floor slab. Patent Document 4 discloses a method of integrating a C-shaped metal fitting embedded in the edge of a precast concrete slab with an H-shaped metal fitting to connect them, and filling the joint and the metal fitting with mortar. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2009-264040 [Patent Document 2] Japanese Patent Publication No. 2015-001045 [Patent Document 3] Japanese Patent Publication No. 2019-002251 [Patent Document 4] Japanese Patent Publication No. 2015-101842 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, these conventional technologies have been criticized for the following problems. (1) Because large quantities of concrete or high-strength fiber-reinforced concrete are used as filler, pouring and curing take time, making on-site work complicated. In addition, the cost increases due to the increased material costs and labor required. (2) In loop joints, the slab thickness must be set to match the loop shape of the reinforcing bars, which generally increases the slab thickness. (3) The process of placing reinforcing bars inside the loop joint is complicated and requires a lot of on-site work and manpower, including setting up the lower formwork, pouring infill concrete, and curing. (4) If a "jaw" is provided to omit the lower formwork, pulling work will be required to avoid interference with the reinforcing bars when installing the floor slab, which will reduce work efficiency. (5) Even when anchoring bodies are provided at the ends of the reinforcing bars or when high-strength fiber-reinforced concrete is used, the constraints on the slab thickness are relaxed compared to loop joints, but on-site work such as setting up the lower formwork, pouring infill concrete, and curing is still required. (6) When specialized metal fittings are used for joints, the material costs become high. (7) When high-strength fiber-reinforced concrete or specialized metal fittings are used in the joints, the strength of the joint area may become excessively high, potentially causing damage to be unevenly distributed to other parts. (8) In recent years, in particular, replacement work of precast concrete deck slabs has been widely carried out for the repair and renewal of expressways and bridges, and especially on expressways with heavy traffic, it is necessary to carry out repair and renewal work in a short period of time in order to minimize the impact on traffic.

[0007] The present invention aims to provide a precast concrete slab, a joining structure for precast concrete slabs, and a joining method for precast concrete slabs that can be joined in a short construction period. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a precast concrete slab having a concave joint at one end and a convex joint at the other end, wherein the concave joint has a plurality of grooves provided on the upper surface of the precast concrete slab perpendicular to the end face of the one end and continuous laterally with respect to the end face of the one end, and the convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other end of the precast concrete slab and are arranged in parallel and continuous laterally with respect to the end face of the other end, and a plurality of convex-side anchoring plates inserted through the tip of each of the protruding reinforcing bars, wherein the grooves of the concave joint do not penetrate to the lower surface of the precast concrete slab and are capable of accommodating the protruding reinforcing bars and convex-side anchoring plates corresponding to each of the grooves.

[0009] Furthermore, the present invention relates to a precast concrete slab joining structure for joining two precast concrete slabs, wherein one precast concrete slab has a concave joint on its end face and the other precast concrete slab has a convex joint on its end face, the concave joint and the convex joint face each other, there is a predetermined gap between the end face of the one precast concrete slab and the end face of the other precast concrete slab, and the concave joint is on the upper surface of the one precast concrete slab, perpendicular to the end face of the one precast concrete slab, and the one precast concrete slab The concrete slab has a plurality of grooves provided continuously in the lateral direction with respect to the end face of the concrete slab, and the convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other precast concrete slab and are arranged in parallel in the lateral direction with respect to the end face of the other precast concrete slab, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars, and the grooves do not penetrate to the lower surface of the one precast concrete slab, and each of the grooves accommodates the protruding reinforcing bars and convex-side anchoring plates of the corresponding convex joint, and is characterized by having a filler material that is filled and hardened in the gap and grooves.

[0010] The recessed joint has a recessed fixing plate positioned between adjacent grooves, and the recessed fixing plate may be fixed to the tip portion of the reinforcing bar protruding from the end face of one of the ends. The multiple protruding reinforcing bars of the convex joint may be arranged in parallel in two upper and lower rows, and the convex-side anchoring plate may be arranged across the upper and lower protruding reinforcing bars. Each of the multiple grooves in the concave joint may, in a plan view, have a tapered portion in which the width narrows toward the end face of one of the ends, at least in part. The convex joint may have a recess on the end face of the other end. A sealing material that is continuous in the lateral direction may be provided at the lower part of one end face on which the concave joint is provided or the other end face on which the convex joint is provided. The recessed joint has a recessed fixing plate positioned between adjacent grooves, and the recessed fixing plate may be fixed to the tip of a reinforcing bar protruding from the end face of one of the precast concrete slabs. The multiple protruding reinforcing bars of the convex joint may be arranged in parallel in two upper and lower rows, and the convex-side anchoring plate may be arranged across the upper and lower protruding reinforcing bars. Each of the multiple grooves in the concave joint may, in a plan view, have a tapered portion in which its width narrows toward the end face side of one of the precast concrete slabs, at least in part. The aforementioned convex joint may have a recess in the end face of the other precast concrete slab into which the filler material is filled. A sealing material that is continuous in the lateral direction may be provided at the lower part of the end face of one precast concrete slab where the concave joint is provided, or at the lower part of the end face of the other precast concrete slab where the convex joint is provided.

[0011] Furthermore, the present invention relates to a method for joining precast concrete slabs, comprising: installing one precast concrete slab having a concave joint; lifting the other precast concrete slab having a convex joint; lowering the other precast concrete slab so that the protruding reinforcement and the convex-side anchoring plate of the convex joint of the other precast concrete slab fit into the concave joint of the first precast concrete slab; filling the gap with a filler material and allowing it to harden. [Effects of the Invention]

[0012] The present invention provides at least one of the following effects. (1) By reducing the amount of filler material used, the time required for concrete pouring can be shortened, and the complexity of on-site work can be reduced. In addition, cost reductions can be made by reducing material costs and the number of workers. (2) Since it does not use special-shaped steel bars that would increase the thickness of the floor slab like conventional loop steel bars, there is no need to make the thickness of the floor slab larger than necessary. (3) Some on-site operations such as the installation of the lower formwork, the placement of infill concrete, and curing are simplified. At the same time, since the operation of arranging reinforcement bars is not required, the reinforcement bar arrangement work can be omitted, realizing the reduction of the number of workers and the improvement of the efficiency and labor saving of on-site operations. (4) When installing the floor slab, the structure does not require pulling work to avoid interference with the steel bars, so the efficiency of on-site operations can be improved without causing a decrease in work efficiency. (5) Since it can be constructed without using special hardware, the material cost can be suppressed, and economical construction is possible. (6) By not using high-strength fiber-reinforced concrete or special hardware, the strength of the joint part will not become excessively high, and the bias of damage in the entire structure can be suppressed. (7) By reducing the complexity of on-site operations, the work efficiency is high and the work can be carried out in a short construction period. Therefore, even on a highway with a large traffic volume, the impact on traffic can be minimized.

Brief Description of the Drawings

[0013] [Figure 1] Perspective view of the precast concrete floor slab of the present invention according to Example 1 [Figure 2] Explanatory drawing of the state when joining the joint structure [Figure 3] Explanatory drawing of the concave joint [Figure 4] Explanatory drawing of the convex joint [Figure 5] Explanatory drawing of the joint structure (1) [Figure 6] Explanatory drawing of the joint structure (2) [Figure 7] Explanatory drawing of the joining method (1) [Figure 8] Explanatory drawing of the joining method (2) [Figure 9] Explanatory drawing of the joint structure according to Example 2 [Figure 10] Explanatory drawing of the joint structure according to Example 2 [Modes for carrying out the invention]

[0014] The precast concrete slab, the joining structure for the precast concrete slab, and the joining method for the precast concrete slab of the present invention will be described in detail below with reference to the drawings.

[0015] [Example 1] (1) Construction of precast concrete slab The precast concrete slab 1 of the present invention is rectangular in plan view and has joint structures 2 at both opposing ends (Figure 1). The joint structure 2 consists of a concave joint 21 provided at one end and a convex joint 22 provided at the other end. When joining two precast concrete slabs 1a and 1b together, the concave joint 21 provided at the end of one precast concrete slab 1a and the convex joint 22 provided at the end of the other precast concrete slab 1b are positioned opposite each other (Figure 2). The main body of precast concrete slab 1 (including 1a and 1b) is a conventional RC or PC structure slab, and the reinforcement, thickness, and concrete strength are designed according to the required load-bearing capacity. Furthermore, since it does not use specially shaped reinforcing bars that increase the thickness of the slab, such as conventional loop reinforcement bars, there is no need to make the slab thickness unnecessarily large.

[0016] (2) Joint structure (2.1) Concave joint (Figure 3) The recessed joint 21 has multiple grooves 211 on the upper surface of the precast concrete slab 1 that are perpendicular to the end face 11 of one end. The multiple grooves 211 are provided continuously at predetermined intervals in the lateral direction relative to the end face 11. The groove 211 does not penetrate to the underside of the precast concrete slab 1, and can accommodate the protruding reinforcement bars 221 and the convex-side anchoring plate 222 of the convex joint 22, which will be described later. The groove 211 has a tapered portion 211a that narrows in width toward the end face 11 when viewed from above.

[0017] Furthermore, a concave fixing plate 212 is placed between adjacent grooves 211. The concave-side anchoring plate 212 is a rectangular flat plate made of steel, and is fixed to the tip of the reinforcing bar 13 that protrudes horizontally from the end face 11 of the precast concrete floor slab 1. In this embodiment, the concave-side anchoring plate 212 is embedded in the end face 11. A hole is provided in the concave-side anchoring plate 212, and the reinforcing bar 13, whose tip is externally threaded, is inserted through this hole, and the concave-side nut 131 is screwed onto the reinforcing bar 13 and tightened to fix the concave-side anchoring plate 212. In addition, the reinforcing bars 13 are arranged in parallel in two rows, upper and lower, and the concave-side anchoring plate 212 is placed across the upper and lower rows of reinforcing bars 13, thereby creating a structure that connects the upper and lower rows of reinforcing bars 13. The side end of the concave fixing plate 212 may penetrate the tapered portion 211a and protrude into the groove portion 211.

[0018] (2.2) Convex joint (Figure 4) The convex joint 22 is provided with a plurality of protruding reinforcing bars 221 that project horizontally from the end face 12 of the other end of the precast concrete slab 1. The plurality of protruding reinforcing bars 221 are provided continuously at predetermined intervals in the lateral direction relative to the end face 12. The protruding length of each protruding reinforcing bar 221 is such that it fits into the groove 211 of the concave joint 21, which is in the opposite position when the joint structure 2 is engaged.

[0019] A convex-side fixing plate 222 is fixed to the tip of the protruding reinforcement bar 221. The convex-side fixing plate 222 is a rectangular flat plate made of steel. In this embodiment, a hole is provided in the convex-side fixing plate 222, and a protruding reinforcing bar 221 with an external thread at its tip is inserted through this hole. The convex-side nut 223 is screwed onto the protruding reinforcing bar 221, and the concave-side fixing plate 212 is fixed to the convex-side nut 223 by welding or adhesive. Alternatively, the concave-side fixing plate 212 may be fixed directly to the protruding reinforcing bar 221 by welding. Furthermore, the protruding reinforcement bars 221 are arranged in parallel in two rows, upper and lower, and the convex-side anchoring plate 222 is placed across the two rows of protruding reinforcement bars 221, thereby creating a structure that connects the two rows of protruding reinforcement bars 221. The groove 211 of the concave joint 21 is made deep enough to accommodate the two rows of protruding reinforcement bars 221 and the convex-side anchoring plate 222. A recess 224 is provided on the end face 12 from which the protruding reinforcement bar 221 of the convex joint 22 protrudes.

[0020] The joint structure 2 of the present invention is composed of conventionally used reinforcing bars 13 and protruding bars 221, as well as steel concave-side anchoring plates 212 and convex-side anchoring plates 222, eliminating the need for newly developed specialized metal fittings. This reduces material costs compared to using specialized metal fittings, enabling economical construction.

[0021] (3) Joint structure of precast concrete slab Next, a joint structure for two precast concrete slabs 1a and 1b having the above-described joint structure 2 will be explained. It should be noted that the precast concrete slab joint structure of the present invention is not limited to joints between adjacent precast concrete slabs in the bridge axis direction of highways and bridges, but can also be used for joints between adjacent precast concrete slabs in the direction perpendicular to the bridge axis. The precast concrete slabs 1a and 1b to be joined are arranged such that a concave joint 21 is provided at the end of one precast concrete slab 1a and a convex joint 22 is provided at the end of the other precast concrete slab 1b, with the groove 211 of the concave joint 21 accommodating the protruding reinforcement 221 and the convex-side anchoring plate 222 of the corresponding convex joint 22 (Figures 5 and 6). One precast concrete slab 1a and the other precast concrete slab 1b have a predetermined gap between their end faces 11 and 12.

[0022] (3.1) Filling material The gaps and grooves 211 between one precast concrete slab 1a and the other precast concrete slab 1b are filled with a filling material 3 made of mortar that has been filled and hardened. The hardened infill material 3, the protruding reinforcing bars 221 located inside the groove 211, and the convex-side anchoring plate 222 join one precast concrete slab 1a to the other precast concrete slab 1b, making them a single unit. This configuration joins the infill material 3, made of mortar, to the precast concrete slabs 1a and 1b via the groove 211, the protruding reinforcing bars 221, and the convex-side anchoring plate 222, eliminating the need to use high-strength fiber-reinforced concrete or special metal fittings at the joint. Therefore, the strength of the joint portion does not become excessively high, and the risk of uneven distribution of damage throughout the entire structure can be reduced.

[0023] (3.2) Function and effect of concave and convex fixing plates The convex-sided anchoring plate 222 fixed to the tip of the protruding reinforcement bar 221 functions as a resistance material that resists pull-out and shear forces, as well as increasing the adhesion force with the filler material 3. Furthermore, the recessed anchoring plate 212 of the recessed joint 21 connects the upper and lower two rows of reinforcing bars 13, and the convex anchoring plate 222 of the convex joint 22 connects the upper and lower two rows of protruding reinforcing bars 221, thereby distributing the pull-out force and suppressing the occurrence of push-out failure in the cover portion of the filler material 3. When the side end of the recessed anchoring plate 212 protrudes into the groove portion 211, the protruding portion of the recessed anchoring plate 212 also resists pull-out and shear forces and functions as a resistance material that increases the adhesion force with the filler material 3.

[0024] (3.3) Function and effect of the groove The groove 211 that accommodates the protruding reinforcement bar 221 and the convex fixing plate 222 has a tapered portion 211a in plan view that narrows in width toward the end face 11. By providing the tapered portion 211a, the pull-out resistance of the protruding reinforcement bar 221 and the convex fixing plate 222 is improved. The tapered portion 211a may be provided along the entire length of the groove 211, but providing it only in a portion increases the taper angle and thus the pull-out resistance.

[0025] (3.4) Function and effect of depressions If a recess 224 is provided on the end face 12 from which the protruding reinforcement 221 of the convex joint 22 of the other precast concrete slab 1b protrudes, the infill material 3 hardens within the recess 224, forming a shear key, and the shear strength between the hardened infill material 3 and the other precast concrete slab 1b is improved.

[0026] (4)Joining method Next, we will explain the method for joining precast concrete slabs 1a and 1b to form a floor slab.

[0027] (4.1) Lowering (Figure 7) The precast concrete slab 1a, which has a recessed joint 21, is pre-installed in a fixed position. Then, the protruding reinforcement bars 221 and the convex-side anchoring plates 222 of the convex joint 22 of the precast concrete slab 1b, which have been lifted by a crane or the like, are lowered so that they fit into the grooves 211 of the concave joint 21 of the precast concrete slab 1a. At this time, a small gap (about 20 mm) is left between the end face 11 of the precast concrete slab 1a and the end face 12 of the precast concrete slab 1b. This configuration eliminates the need for reinforcing bars to be placed inside the loop joint, which was previously required, thus simplifying the reinforcing bar placement process. Furthermore, this configuration does not include a "jaw" to omit the lower formwork, and the protruding reinforcement bars 221 of the convex joint 22 and the convex side anchoring plate 222 are suspended and joined along the groove 211 of the concave joint 21. As a result, the pulling work required to avoid interference with the reinforcing bars is eliminated, and on-site work can be simplified and made more efficient without reducing work efficiency.

[0028] (4.2) Filling with gap-filling material The gaps, depressions 224, and grooves 211 between the end face 11 of the precast concrete slab 1a and the end face 12 of the precast concrete slab 1b are filled with filler material 3 and allowed to harden (Figure 8). The gap between the end face 11 of the precast concrete slab 1a and the end face 12 of the precast concrete slab 1b can be filled by closing the openings on both ends with side formwork (not shown) and closing the lower opening with bottom formwork 4, and then pouring in the filling material 3 from above. This fills the gap, depressions 224 and grooves 211 between the end face 12 of the precast concrete slab 1b and the slab. Because the gap between the precast concrete slab 1b and the end face 12 is smaller than when using conventional joints, the formwork size can be reduced, simplifying on-site work such as formwork installation and dismantling, and improving on-site work efficiency. Furthermore, since the gap-filling material 3 only needs to fill smaller gaps than those created with conventional joints, and only the depressions 224 and grooves 211, the amount of concrete and high-strength fiber-reinforced concrete used can be significantly reduced. This shortens the time required for pouring and curing, and reduces the complexity of on-site work. In addition, material costs and labor costs can be reduced, resulting in an overall cost reduction.

[0029] The present invention's method for joining precast concrete slabs reduces the complexity of on-site work, enabling construction to be completed in a shorter period, thus minimizing the impact on traffic, even on busy highways.

[0030] [Example 2] (1) Sealant A sealing material 23 made of resin foam, rubber, or the like may be provided in advance at the lower part of the groove 211 of the end face 11 of the precast concrete slab 1a having a recessed joint 21 (Figures 9 and 10). The sealing material 23 is elastic and seals the lower part of the gap when joining precast concrete slabs 1a and 1b together. This eliminates the need to construct a bottom formwork 4 to close the lower opening of the gap when filling it with the filling material 3, thus improving work efficiency on site. The sealing material 23 may be provided at the lower part of the end face 12 of the precast concrete slab 1b. [Explanation of symbols]

[0031] 1(1a, 1b) Precast concrete slab, 11, 12 End faces, 13 Reinforcing bars, 131 Recessed nuts, 2. Joint structure, 21 recessed joint, 211 groove, 211a tapered portion, 212 recessed side fixing plate, 22 Convex joint, 221 Protruding reinforcement, 222 Convex side anchoring plate, 223 Convex side nut, 224 Recess, 23. Sealant 3. Filling material 4. Bottom formwork

Claims

1. A precast concrete slab having a concave joint at one end and a convex joint at the other end, The recessed joint has a plurality of grooves provided on the upper surface of the precast concrete slab, perpendicular to the end face of one end and continuous in a lateral direction with respect to the end face of one end. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other end of the precast concrete slab and are arranged in a continuous parallel manner in the lateral direction relative to the end face of the other end, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion of the concave joint does not penetrate to the lower surface of the precast concrete slab, and is capable of accommodating the protruding reinforcement and the convex anchoring plate corresponding to each of the groove portions. The recessed joint has a recessed fixing plate positioned between adjacent grooves, The recessed anchoring plate is fixed to the tip portion of the reinforcing bar protruding from the end face of one of the ends, in a precast concrete slab.

2. The side end of the recessed fixing plate is characterized by protruding into the groove. The precast concrete slab according to claim 1.

3. A precast concrete slab having a concave joint at one end and a convex joint at the other end, The recessed joint has a plurality of grooves provided on the upper surface of the precast concrete slab, perpendicular to the end face of one end and continuous in a lateral direction with respect to the end face of one end. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other end of the precast concrete slab and are arranged in a continuous parallel manner in the lateral direction relative to the end face of the other end, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion of the concave joint does not penetrate to the lower surface of the precast concrete slab, and is capable of accommodating the protruding reinforcement and the convex anchoring plate corresponding to each of the groove portions. The multiple protruding reinforcing bars of the aforementioned convex joint are arranged in parallel in two upper and lower rows. The convex fixing plate is characterized by being arranged across the upper and lower protruding reinforcing bars. Precast concrete slab.

4. A precast concrete slab having a concave joint at one end and a convex joint at the other end, The recessed joint has a plurality of grooves provided on the upper surface of the precast concrete slab, perpendicular to the end face of one end and continuous in a lateral direction with respect to the end face of one end. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other end of the precast concrete slab and are arranged in a continuous parallel manner in the lateral direction relative to the end face of the other end, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion of the concave joint does not penetrate to the lower surface of the precast concrete slab, and is capable of accommodating the protruding reinforcement and the convex anchoring plate corresponding to each of the groove portions. Each of the plurality of grooves in the recessed joint is characterized in that, in a plan view, at least a portion of it has a tapered portion that narrows in width toward the end face side of one end. Precast concrete slab.

5. A precast concrete slab having a concave joint at one end and a convex joint at the other end, The recessed joint has a plurality of grooves provided on the upper surface of the precast concrete slab, perpendicular to the end face of one end and continuous in a lateral direction with respect to the end face of one end. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other end of the precast concrete slab and are arranged in a continuous parallel manner in the lateral direction relative to the end face of the other end, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion of the concave joint does not penetrate to the lower surface of the precast concrete slab, and is capable of accommodating the protruding reinforcement and the convex anchoring plate corresponding to each of the groove portions. The aforementioned convex joint is characterized by having a recess on the end face of the other end, Precast concrete slab.

6. The device is characterized by having a sealing material that is continuous in the lateral direction at the lower part of one end face where the concave joint is provided or the other end face where the convex joint is provided. The precast concrete slab according to claim 1.

7. A precast concrete slab joining structure for joining two precast concrete slabs, One precast concrete slab has a concave joint on its end face, and the other precast concrete slab has a convex joint on its end face, with the concave joint and the convex joint facing each other, and a predetermined gap between the end face of one precast concrete slab and the end face of the other precast concrete slab. The recessed joint has a plurality of grooves provided on the upper surface of one precast concrete slab, perpendicular to the end face of the one precast concrete slab, and continuous in a lateral direction with respect to the end face of the one precast concrete slab. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other precast concrete slab and are arranged in a continuous parallel manner laterally to the end face of the other precast concrete slab, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion does not penetrate to the lower surface of one of the precast concrete slabs, and each of the groove portions accommodates the protruding reinforcement and the convex-side anchoring plate of the corresponding convex joint. The gap and the groove are filled with a hardened filler material, The recessed joint has a recessed fixing plate positioned between adjacent grooves, A joint structure for a precast concrete slab, characterized in that the recessed anchoring plate is fixed to the tip portion of a reinforcing bar protruding from the end face of one of the precast concrete slabs.

8. The side end of the recessed fixing plate is characterized by protruding into the groove. The joint structure for precast concrete slabs according to claim 7.

9. A joining structure for precast concrete slabs, for joining two precast concrete slabs, One precast concrete slab has a concave joint on its end face, and the other precast concrete slab has a convex joint on its end face, with the concave joint and the convex joint facing each other, and a predetermined gap between the end face of one precast concrete slab and the end face of the other precast concrete slab. The recessed joint has a plurality of grooves provided on the upper surface of one precast concrete slab, perpendicular to the end face of the one precast concrete slab, and continuous in a lateral direction with respect to the end face of the one precast concrete slab. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other precast concrete slab and are arranged in a continuous parallel manner laterally to the end face of the other precast concrete slab, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion does not penetrate to the lower surface of one of the precast concrete slabs, and each of the groove portions accommodates the protruding reinforcement and the convex-side anchoring plate of the corresponding convex joint. The gap and the groove are filled with a hardened filler material, The multiple protruding reinforcing bars of the aforementioned convex joint are arranged in parallel in two upper and lower rows. The convex fixing plate is characterized by being arranged across the upper and lower protruding reinforcing bars. Joining structure for precast concrete slabs.

10. A precast concrete slab joining structure for joining two precast concrete slabs, One precast concrete slab has a concave joint on its end face, and the other precast concrete slab has a convex joint on its end face, with the concave joint and the convex joint facing each other, and a predetermined gap between the end face of one precast concrete slab and the end face of the other precast concrete slab. The recessed joint has a plurality of grooves provided on the upper surface of one precast concrete slab, perpendicular to the end face of the one precast concrete slab, and continuous in a lateral direction with respect to the end face of the one precast concrete slab. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other precast concrete slab and are arranged in a continuous parallel manner laterally to the end face of the other precast concrete slab, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion does not penetrate to the lower surface of one of the precast concrete slabs, and each of the groove portions accommodates the protruding reinforcement and the convex-side anchoring plate of the corresponding convex joint. The gap and the groove are filled with a hardened filler material, Each of the multiple grooves in the concave joint is characterized in that, in a plan view, at least a portion of it has a tapered portion that narrows in width toward the end face side of one of the precast concrete slabs. Joining structure for precast concrete slabs.

11. A joining structure for precast concrete slabs, for joining two precast concrete slabs, One precast concrete slab has a concave joint on its end face, and the other precast concrete slab has a convex joint on its end face, with the concave joint and the convex joint facing each other, and a predetermined gap between the end face of one precast concrete slab and the end face of the other precast concrete slab. The recessed joint has a plurality of grooves provided on the upper surface of one precast concrete slab, perpendicular to the end face of the one precast concrete slab, and continuous in a lateral direction with respect to the end face of the one precast concrete slab. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other precast concrete slab and are arranged in a continuous parallel manner laterally to the end face of the other precast concrete slab, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion does not penetrate to the lower surface of one of the precast concrete slabs, and each of the groove portions accommodates the protruding reinforcement and the convex-side anchoring plate of the corresponding convex joint. The gap and the groove are filled with a hardened filler material, The aforementioned convex joint is characterized by having a recess in the end face of the other precast concrete slab into which the filler material is filled. Joining structure for precast concrete slabs.

12. A precast concrete slab joining structure for joining two precast concrete slabs, One precast concrete slab has a concave joint on its end face, and the other precast concrete slab has a convex joint on its end face, with the concave joint and the convex joint facing each other, and a predetermined gap between the end face of one precast concrete slab and the end face of the other precast concrete slab. The recessed joint has a plurality of grooves provided on the upper surface of one precast concrete slab, perpendicular to the end face of the one precast concrete slab, and continuous in a lateral direction with respect to the end face of the one precast concrete slab. The aforementioned convex joint has a plurality of protruding reinforcing bars that protrude from the end face of the other precast concrete slab and are arranged in a continuous parallel manner laterally to the end face of the other precast concrete slab, and a plurality of convex-side anchoring plates that are inserted through the tip of each of the protruding reinforcing bars. The groove portion does not penetrate to the lower surface of one of the precast concrete slabs, and each of the groove portions accommodates the protruding reinforcement and the convex-side anchoring plate of the corresponding convex joint. The gap and the groove are filled with a hardened filler material, The invention is characterized by having a sealing material that is continuous in the lateral direction at the lower part of the end face of one precast concrete slab where the concave joint is provided, or at the lower part of the end face of the other precast concrete slab where the convex joint is provided. Joining structure for precast concrete slabs.

13. A method for joining precast concrete slabs, wherein precast concrete slabs described in any one of claims 1 to 6 are joined together, Install the one precast concrete slab having the recessed joint, The other precast concrete slab having the aforementioned protruding joint is lifted up, A predetermined gap is provided between the end face of one precast concrete slab and the end face of the other precast concrete slab so that the protruding reinforcement and the convex-side anchoring plate of the convex joint of the other precast concrete slab fit into the concave joint of the one precast concrete slab, and the other precast concrete slab is lowered. The method is characterized by filling the gap with a filler material and allowing it to harden. Method for joining precast concrete slabs.

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