Production method of precast concrete product, and fixture therefor

Abstract

To provide a method and fixtures allowing assembly work of fixtures to be more easily carried out using only a pair of upper and lower fixtures when producing a precast concrete product having two reinforcement bars in a vertical direction, at least one end of which projects outside.SOLUTION: A production method of a precast concrete product comprises: (A) a lower side fixture installation process of installing a lower side fixture provided with a first lower side groove part, a first upper side groove part, and a first lower side oblique surface and a second lower side oblique surface connecting the first lower side groove part and the first upper side groove part outside of a position becoming a projected end surface; (B) a reinforcement bar placement process of placing a lower side reinforcement bar in the first lower side groove part and an upper side reinforcement bar in the first upper side groove part from an upper side of the lower side fixture; (C) a fixture assembly process of making a seam between both of the fixtures substantially watertight by assembling, from an upper side of the lower side fixture, an upper side fixture provided with a first upper side oblique surface and a second upper side oblique surface; and (D) a curing process of pouring uncured concrete from an upper space of both of the fixtures and curing the concrete.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing precast concrete products and a jig therefor.

Background Art

[0002] In order to manufacture precast concrete products containing steel bars inside, various contrivances are made according to the characteristics of the concrete products. For example, Patent Document 1 discloses a contrivance for manufacturing a hollow precast concrete member. FIG. 11 shows a precast concrete product 100 containing two steel bars 101 and 102 in the vertical direction and having one end protruding outward. If the ends of the steel bars 101 and 102 are linear, it is sufficient to provide holes through which the steel bars 101 and 102 pass in a jig as a formwork when pouring concrete. However, when the ends of the steel bars 101 and 102 are not linear (for example, when the edges are bent in an L shape or when they bulge larger than the diameter of the steel bar), appropriate contrivance is required because the jig cannot be removed in the extending direction of the steel bar after the concrete has hardened.

[0003] In this case, for example, the jigs 103 to 105 disclosed in FIG. 12 can be used. This jig is divided into three stages: an upper stage 103, a middle stage 104, and a lower stage 105. Groove portions 103A and 105A that allow the passage of steel bars are provided at predetermined intervals in the upper stage 103 and the lower stage 105, respectively. For the other wall surfaces, a conventionally used wall body is used as the jig. By using the jigs 103 to 105 to create a formwork on the wall surface where the steel bar extends and removing the jigs 103 to 105 after the concrete has hardened in the formwork, a concrete product with a steel bar having one end that is not linear protruding can be manufactured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above manufacturing method, at least three jigs are required, and the assembly process and the manufacturing process become complicated. The present invention has been made in view of the above circumstances, and its object is to provide a precast concrete product containing two reinforcing bars in the vertical direction, at least one end of which protrudes outward in a form that is not linear. When manufacturing, only a pair of upper and lower jigs are required, and the jig assembly operation can be made simpler.

Means for Solving the Problems

[0006] A method for manufacturing a precast concrete product according to the invention for achieving the above object is a method for manufacturing a product in which a pair of upper and lower two reinforcing bars arranged at the same position vertically extend from a protruding end face which is at least one end face of concrete, and a part of the extended edge of the reinforcing bar is not linear. The method includes: (A) a lower jig installation step of installing a lower jig having a first lower groove portion outside the position of the protruding end face, a first upper groove portion located vertically above this groove portion, a first lower inclined surface connecting between the two groove portions, and a second lower inclined surface; (B) a reinforcing bar placement step of placing the lower reinforcing bar in the first lower groove portion and the upper reinforcing bar in the first upper groove portion from above the lower jig; (C) a jig combination step of combining an upper jig having a second lower groove portion, a second upper groove portion, a first upper inclined surface connecting between the two groove portions, and a second upper inclined surface from above the lower jig to make the joint of the two jigs substantially watertight; (D) a concrete hardening step of pouring concrete before hardening from the upper space of the two jigs and hardening the concrete.

[0007] According to the above invention, by using a pair of upper and lower jigs, a predetermined concrete product can be manufactured. Therefore, compared with the conventional construction method, fewer jigs are required. In the above invention, "a part of the edge is not linear" means a structure that cannot be removed simply by providing a groove in the jig and only moving the jig in the extending direction of the reinforcing bar after the production of the concrete product. Such structures include, for example, a structure in which a diameter-enlarged member with a large diameter is attached to the edge portion of the reinforcing bar (examples of the diameter-enlarged member include a nut, a disc-shaped member, a square member, a rectangular member, a hexagonal member, etc.), a structure in which the edge of the reinforcing bar is bent in an L shape or a U shape, and the like. "The same position vertically" does not mean exactly the same position without any difference, but includes a slight displacement (for example, a displacement of about half the radius of the reinforcing bar from the center position of the upper and lower reinforcing bars) that can be accommodated by the inclined surface.

[0008] The protruding end face does not necessarily have to be only one face, but may also be two faces, three faces, four faces, etc. According to the invention of the present application, the protruding end face can be accommodated regardless of whether it is one to four faces. A precast concrete product means a concrete product manufactured in advance at a factory, and means concrete products such as side ditches, pipes, manholes, culverts, bridge girders, parts of buildings, and concrete floor slabs. In the above invention, it is preferable to provide a jig fixing step (W) for fixing the positions of the two jigs between the (C) jig combination step and the (D) concrete hardening step. By doing so, it becomes easier to avoid causing a displacement in the positions of the two jigs while pouring the concrete.

[0009] A jig for manufacturing a precast concrete product according to another invention is a pair of upper and lower jigs for manufacturing a product in which at least a part of the edge of the extended end of a reinforcing bar is not linear, with two reinforcing bars arranged vertically extending from positions aligned vertically on a protruding end face which is at least one end face of the concrete product. The lower jig is provided with a first lower groove portion on the lower surface side of the lower reinforcing bar that can be placed outside the protruding end face, a first upper groove portion on the lower surface side of the upper reinforcing bar that can be placed, and a first lower inclined surface and a second lower inclined surface connecting between the two groove portions. On the other hand, the upper jig is provided with a second lower groove portion covering the upper surface side of the lower reinforcing bar, a second upper groove portion covering the upper surface side of the upper reinforcing bar, and a first upper inclined surface and a second upper inclined surface connecting between the two groove portions.

Advantages of the Invention

[0010] According to the present invention, when manufacturing a precast concrete product containing two reinforcing bars in the vertical direction and at least one end of the reinforcing bar protruding outward, only a pair of upper and lower types of jigs are required, and the assembly operation of the jigs can be made simpler.

Brief Description of the Drawings

[0011]

Figure 1

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Figure 12

Mode for Carrying Out the Invention

[0012] Next, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited by these embodiments, and it can be implemented in various forms without changing the gist of the invention. <Configuration of Precast Concrete Product> In FIGS. 1 to 3, a precast concrete product 1 (hereinafter referred to as "product 1") manufactured in this embodiment is shown. This product 1 is used, for example, on a highway by aligning a plurality of them in the traveling direction (vertical direction in FIG. 2) and pouring concrete from above to fix them. In product 1, two reinforcing bars 4 and 5 extend vertically from a pair of protruding end faces 2 and 3 at the front and rear. The reinforcing bars 4 and 5 extend side by side from the protruding end faces 2 and 3 at substantially the same position vertically, and the leading edge of the tip is not linear. At the tips of the reinforcing bars 4 and 5, disk-shaped diameter-expanded members 6 having a diameter larger than the diameter of the reinforcing bars 4 and 5 are provided. This product 1 is designed to arrange a plurality of them in alignment in the direction in which the reinforcing bars 4 and 5 protrude. In addition, so that the reinforcing bars 4 and 5 protruding from the adjacent products 1 and 1 do not interfere with each other, the positions where the reinforcing bars 4 and 5 protrude from the protruding end faces 2 and 3 are manufactured with a slight displacement from each other in the left-right direction in FIG. 2.

[0013] <Configuration of Upper and Lower Jigs> Figure 4 shows the temporary reinforcement 8 with the reinforcing bars 4, 5, and 7 temporarily assembled for manufacturing the product 1, and the state before assembling a part of the jigs 10 and 11. The upper jig 10 and the lower jig 11 are each configured as a pair of upper and lower parts, and are provided with groove portions 21, 22, 31, and 32 capable of accommodating the reinforcing bars 4 and 5, respectively. First, the configuration of the lower jig 11 is described as follows. The lower jig 11 is mainly composed of a plate-like portion 25 bent into an L-shaped cross-section and a rib portion 26 for reinforcing each part of the plate-like portion 25. Among these, on the plate-like portion 25, outside the protruding end faces 2 and 3, a first lower groove portion 21 capable of placing the lower surface side of the lower reinforcing bar 5, a first upper groove portion 22 capable of placing the lower surface side of the upper reinforcing bar 4, a first lower inclined surface 23 connecting between the two groove portions 21 and 22, and a second lower inclined surface 24 are provided. Each of the groove portions 21 and 22 is configured to cover the lower half circumference of the reinforcing bars 4 and 5, respectively. Each of the groove portions 21 and 22 is provided in 13 pieces each in accordance with the number of the reinforcing bars 4 and 5 (see also Figure 5). The groove portions 21 and 22 arranged vertically are provided so as to be at substantially the same position in the vertical direction. The first lower inclined surface 23 is provided on the lower surface side of the plate-like portion 25. On the other hand, the second lower inclined surface 24 is provided on the upper surface side of the plate-like portion 25. Among the two inclined surfaces 23 and 24, the inclination angle of the first lower inclined surface 23 is larger than the inclination angle of the second lower inclined surface 24.

[0014] Among the spaces between the adjacent inclined surfaces 23 and 24 where the plate-like portion 25 exists, it is a fitting protrusion 27. The fitting protrusion 27 is formed in a tapered shape that tapers upward from the groove portion 21. Also, among the adjacent inclined surfaces 23 and 24, (where there is no plate-like portion 25) and it is a space, it is a fitting recess 28. The fitting recess 28 is formed to be tapered toward the back side (lower side). Also, at two fitting protrusions 27, screw hole portions 29 are provided at intermediate positions in the height direction. The inclined surfaces 24A and 24B at both ends end at the intermediate position of the fitting protrusion 27, and end walls 25A and 25B extend horizontally from there to both ends.

[0015] Next, the configuration of the upper jig 10 will be described. The upper jig 10 and the lower jig 11 have substantially the same configuration. The upper jig 10 includes a plate-shaped portion 35 having an L-shaped cross section and a rib portion 36 that appropriately reinforces the plate-shaped portion 35. On the plate-shaped portion 35, outside the protruding end faces 2 and 3, a second lower groove portion 31 that covers the upper surface side of the lower reinforcing bar 5, a second upper groove portion 32 that covers the upper surface side of the upper reinforcing bar 4, a first upper inclined surface 33 and a second upper inclined surface 34 that connect between the two groove portions 31 and 32 are provided. Each of the groove portions 31 and 32 is configured to cover the upper half circumference of the reinforcing bars 4 and 5, respectively. Each of the groove portions 31 and 32 is provided with 13 each as shown in the figure in accordance with the number of the reinforcing bars 4 and 5. The groove portions 31 and 32 arranged vertically are provided so as to be substantially at the same position in the vertical direction. The first upper inclined surface 33 is provided on the lower surface side of the plate-shaped portion 35. On the other hand, the second upper inclined surface 34 is provided on the upper surface side of the plate-shaped portion 35.

[0016] Among the inclined surfaces provided on the upper and lower jigs 10 and 11, the second lower inclined surface 24 and the first upper inclined surface 33, and the first lower inclined surface 23 and the second upper inclined surface 34 have the same inclination angle with respect to each other. Among the adjacent inclined surfaces 33 and 34, where the plate-shaped portion 35 exists, it is a fitting protrusion 37. The fitting protrusion 37 is formed in a tapered shape that tapers downward. On the other hand, among the adjacent inclined surfaces 33 and 34, where there is a space, it is a fitting recess 38. The fitting recess 38 is shaped to taper toward the back side.

[0017] At the intermediate position in the height direction of the two fitting protrusions 37, a screw hole portion 39 is provided. The inclined surfaces 33A and 33B at both ends end at the intermediate position of the fitting protrusion 37, and from there, end walls 35A and 35B extend horizontally to both ends. In the upper and lower jigs 10 and 11, the assembly protrusion 27 and the assembly recess 38, and the assembly protrusion 37 and the assembly recess 28 are slidably assembled to each other. When the upper and lower jigs 10 and 11 are slidably assembled, between the two protrusions and the two recesses, the inclined surfaces 33, 24 and the inclined surfaces 34, 23 are in substantially surface contact with each other, so that the inner concrete does not flow out and they are assembled in a substantially watertight manner. Further, in the screw holes 29 and 39, when the upper and lower jigs 10 and 11 are assembled, an assembly screw 51 for assembling the connecting member 50 is turned.

[0018] <Method for manufacturing precast concrete products> Next, a method for manufacturing the product 1 using the upper and lower jigs 10 and 11 will be described. As shown in FIGS. 4 and 5, when assembling the jigs 10 and 11, the reinforcing bars 4, 5, 6, and 7 located inside the product 1 in advance are temporarily assembled. At the time of temporary assembly, in addition to the upper and lower reinforcing bars 4 and 5, another reinforcing bar 7 is used, and a stiffener or the like is used to make it substantially rectangular parallelepiped. The temporarily assembled reinforcing bars 4, 5, 6, and 7 in a predetermined shape are called temporarily assembled reinforcing bars 8. Thus, the lower jig 11 is installed at a predetermined position (lower jig installation step). Next, as shown by the arrow X in FIG. 5, the temporarily assembled reinforcing bar 8 is assembled from above the lower jig 11. Specifically, the position of the temporarily assembled reinforcing bar 8 is slightly slid in the direction of the arrow X (left side in the figure), and is moved to the back side (downward) along the second lower inclined surfaces 24 and 24A so that the lower reinforcing bar 5 fits into the assembly recess 28. When the temporarily assembled reinforcing bar 8 is moved downward, the lower reinforcing bar 5 slides slightly to the right side in the figure according to the inclination of the inclined surfaces 24 and 24A, and finally fits into the first lower groove 21. Since the upper reinforcing bar 4 is vertically above the lower reinforcing bar 5, it will fit into the first upper groove 22. Thus, it is assembled into the state shown in FIG. 6 (reinforcing bar placement step). In FIG. 6, in order to make the assembly mode of the reinforcing bars 4 and 5 and the jigs 10 and 11 easy to understand, the structures (6 and 7) other than the reinforcing bars 4 and 5 are shown omitted (the same applies to FIGS. 7 and 8).

[0019] Next, as shown by the arrow Y in Fig. 6, the upper jig 10 is assembled from above the lower jig 11 and the reinforcing bars 4 and 5. That is, the position of the upper jig 10 is slightly slid in the direction of the arrow Y (the left side in the figure) so that the assembling protrusion 37 fits into the assembling recess 28, and it is moved backward (downward) so that the first upper inclined surfaces 33 and 33A are along the second lower inclined surfaces 24 and 24A. As the upper jig 10 moves downward, it slides slightly to the right side in the figure according to the inclination of the second lower inclined surfaces 24 and 24A, and finally the assembling protrusion 37 fits into the assembling recess 28 and the assembling protrusion 27 fits into the assembling recess 38. At this time, the upper half surface of the upper reinforcing bar 4 fits into the second upper groove portion 32, and the upper half surface of the lower reinforcing bar 5 fits into the second lower groove portion 31. Thus, as shown in Fig. 7, the temporarily assembled reinforcing bar 8 is in a state assembled by the upper and lower jigs 10 and 11 (jig combination process). At this time, between the first upper inclined surface 33 and the second lower inclined surface 24, and between the second upper inclined surface 34 and the first lower inclined surface 23, they are assembled in a substantially watertight manner. Also, between the upper reinforcing bar 4 and the second upper groove portion 32 and the first upper groove portion 22, and between the lower reinforcing bar 5 and the first lower groove portion 21 and the second lower groove portion 31, they are assembled in a substantially watertight manner.

[0020] Next, the connecting member 50 shown above Fig. 7 is assembled to the jigs 10 and 11. The connecting member 50 is formed in a rectangular shape with a U-shaped cross section, and screw hole portions 50A are provided at positions corresponding to the screw hole portions 29 and 30 of the upper and lower jigs 10 and 11 respectively. As shown in Figs. 8 and 9, the screw hole portions 29, 39, and 50A of the connecting member 50 and the upper and lower jigs 10 and 11 are aligned, and the assembling screw 51 is turned from the outside of the connecting member 50. Thus, as shown in Fig. 10, the upper and lower jigs 10 and 11 are positioned and fixed by the connecting member 50 (jig fixing process). For the normal end faces where the reinforcing bars 4 and 5 do not protrude, a conventional wall-shaped jig (not shown) is used to form the frame body. Finally, the uncured concrete is poured from the upper space between the two jigs 10 and 11, and the concrete is cured to manufacture the product 1 (concrete curing process). After the concrete has hardened, the jig 10 and 11 are slid and removed in the reverse order of the above procedure to take out the single product 1.

[0021] As described above, according to this embodiment, when manufacturing the product 1 containing two reinforcing bars 4 and 5 in the vertical direction and at least one end of the reinforcing bars protruding outward, only a pair of upper and lower types of jigs 10 and 11 are required, and the assembling operation of the jigs can be made simpler. In this embodiment, among the six end faces of the product, the reinforcing bars extend from a pair of upper and lower end faces. However, according to the present invention, the protruding end face from which the reinforcing bars extend may be any one of one, three, or four faces. In this embodiment, disk-shaped diameter-expanding members with a large diameter are provided at the edges of the reinforcing bars extending in a pair in the vertical direction. However, according to the present invention, other non-linear structures (for example, a structure in which a member (nut, polygonal member, etc.) with an increasing outer diameter is fixed to the edge of the reinforcing bar), a structure in which the tip is bent into an L-shape or a U-shape may also be used.

Explanation of reference numerals

[0022] 1... Precast concrete product (product), 2, 3... Protruding end face, 4, 5... Reinforcing bar, 10... Upper jig, 11... Lower jig, 21... First lower groove portion, 22... First upper groove portion, 23... First lower inclined surface, 24... Second lower inclined surface, 27... Assembly protrusion, 28... Assembly recess, 31... Second lower groove portion, 32... Second upper groove portion, 33... First upper inclined surface, 34... Second upper inclined surface, 37... Assembly protrusion, 38... Assembly recess

Claims

1. A method for manufacturing a product in which a pair of upper and lower reinforcing bars arranged vertically at the same position extend perpendicularly from a protruding end face that is at least one end face of concrete, and a part of the extended edge of the reinforcing bar is not linear, comprising: (A) A lower jig installation step of installing a lower jig having a first lower groove portion outside the position of the protruding end face, a first upper groove portion positioned vertically above this groove portion, a first lower inclined surface connecting between the two groove portions, and a second lower inclined surface; (B) A reinforcing bar placement step of placing a lower reinforcing bar in the first lower groove portion and an upper reinforcing bar in the first upper groove portion from above the lower jig; (C) A jig combination step of combining an upper jig having a second lower groove portion, a second upper groove portion, a first upper inclined surface connecting between the two groove portions, and a second upper inclined surface above the lower jig to make the joint of the two jigs substantially watertight; (D) A concrete hardening step of pouring uncured concrete into the space above the two jigs and hardening the concrete. A method for manufacturing a precast concrete product, characterized by comprising the above steps.

2. The method for manufacturing a precast concrete product according to Claim 1, wherein a jig fixing step (W) of fixing the positions of the two jigs is provided between the jig combination step (C) and the concrete hardening step (D).

3. A pair of upper and lower jigs for manufacturing a product in which a pair of upper and lower reinforcing bars arranged vertically extend from a position arranged vertically at a protruding end face that is at least one end face of a concrete product, and a part of the extended edge of the reinforcing bar is not linear. The lower jig is provided with a first lower groove portion capable of placing the lower surface side of the lower reinforcing bar outside the protruding end face, a first upper groove portion capable of placing the lower surface side of the upper reinforcing bar, a first lower inclined surface connecting between the two groove portions, and a second lower inclined surface. On the other hand, the upper jig is provided with a second lower groove portion covering the upper surface side of the lower reinforcing bar, a second upper groove portion covering the upper surface side of the upper reinforcing bar, a first upper inclined surface connecting between the two groove portions, and a second upper inclined surface. A jig for manufacturing a precast concrete product, characterized by the above structure.

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