Formwork structure and method for manufacturing a concrete member

Abstract

To provide a flask structure capable of improving the workability of preparation and installation, and a concrete member production method.SOLUTION: A flask structure according to an embodiment is a flask structure 1 used for the production of a concrete member. The flask structure 1 comprises: an inner flask 2 exhibiting a plate-like shape and having a through hole passing through in a plate thickness direction A3; an outer flask 3 located in a side opposite to an installation space S to be installed with concrete viewed from the inner flask 2; a projection member 4 fixed to the outer flask 3 and passed through the through hole to project to the installation space S; and an interval holding member 5 holding the intervals between the inner flask 2 and the outer flask 3 in a state where the projection member 4 projects to the installation space S.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a formwork structure used for manufacturing concrete members and a method for manufacturing concrete members.

Background Art

[0002] Japanese Patent No. 2948158 describes a formwork for manufacturing a precast concrete floor slab. The formwork has a bottom frame, a pair of side frames extending in its longitudinal direction, and end plates located at both longitudinal ends of the bottom frame. The surface plate of the bottom frame has unevenness such that the slab thickness is thick above the support girders and thin at the intermediate spans and cantilever portions.

[0003] Japanese Unexamined Patent Application Publication No. 2020 - 60059 describes a method for manufacturing a precast concrete member and a formwork. The formwork has a rigid surface formwork made of steel and a protruding formwork made of a frustum - shaped elastic member. The surface formwork is configured in a box shape by an upper surface, a lower surface, and side surfaces, and has a space inside. Holes are provided in the upper surface of the surface formwork. The space inside the surface formwork communicates with the outside through the holes. The holes are provided for each respective chamber.

[0004] The protruding formwork is detachable from the surface formwork. Fixing and releasing (detaching) the protruding formwork to / from the surface formwork are performed by adjusting the air pressure in each chamber of the space inside the surface formwork using air pressure adjusting means such as a valve. When the air pressure inside the chamber is reduced below atmospheric pressure, the protruding formwork is adsorbed to the surface formwork side through the above - mentioned holes and fixed to the upper surface of the surface formwork. On the other hand, when the chamber is at normal pressure (atmospheric pressure) or pressurized more than the atmosphere, the protruding formwork is not fixed to the surface formwork. The protruding formwork is made using expanded polystyrene such as EPS (Expanded PolyStyrene) or rubber.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The above-described formwork includes a steel surface formwork and a protruding formwork that is detachable from the upper surface provided with holes, and the protruding formwork is made of rubber or the like. In this formwork, concrete is placed in the space formed on the protruding formwork side. Therefore, mortar or fibers may enter between the protruding formwork and the surface formwork when placing the concrete, so post-finishing may be required. In addition, it may be necessary to attach and detach the protruding formwork to the surface formwork each time concrete is manufactured. Therefore, there is room for improvement in terms of the workability of preparing and installing the formwork.

[0007] An object of the present disclosure is to provide a formwork structure and a method for manufacturing a concrete member that can improve the workability of preparation and installation.

Means for Solving the Problems

[0008] The gist of the present disclosure is as follows. [1] A formwork structure used for manufacturing a concrete member, An inner formwork having a plate shape and a through hole penetrating in the plate thickness direction, An outer formwork located on the side opposite to the placement space where concrete is placed as viewed from the inner formwork, A convex member fixed to the outer formwork and passed through the through hole to protrude into the placement space, A spacing holding member that holds the spacing between the inner formwork and the outer formwork in a state where the convex member protrudes into the placement space, Comprising Formwork structure. [2] The convex member has a tapered portion in which the cross-sectional area of the convex member becomes smaller as it separates from the outer formwork when cut along a plane extending along the inner formwork. The formwork structure described in [1]. [3] The convex member is made of an elastic material. The formwork structure described in [1] or [2]. [4] The convex member forms a concave portion in the ridge portion of the concrete member. The inner formwork forms a convex portion in the ridge portion. The formwork structure according to any one of [1] to [3]. [5] A step of defining a placing space where concrete is placed by installing an inner formwork that is plate-shaped and has a through-hole penetrating in the plate thickness direction; A step of projecting the convex member into the placing space through a through-hole of the inner formwork and through a convex member fixed to the outer formwork; A step of installing a spacing member for maintaining the spacing between the inner formwork and the outer formwork while the convex member projects into the placing space; A step of placing concrete in the placing space; Comprising A method for manufacturing a concrete member.

[0009] The formwork structure according to the present disclosure is a formwork structure used for manufacturing a concrete member. The formwork structure includes an inner formwork that is plate-shaped and has a through-hole penetrating in the plate thickness direction, an outer formwork located on the side opposite to the placing space where concrete is placed as viewed from the inner formwork, a convex member fixed to the outer formwork and passed through the through-hole to project into the placing space, and a spacing member for maintaining the spacing between the inner formwork and the outer formwork while the convex member projects into the placing space.

[0010] This formwork structure has an inner formwork and an outer formwork that are plate-shaped, and the distance between the inner formwork and the outer formwork is maintained by a distance retaining member. The inner formwork has a through hole that penetrates in its plate thickness direction. The outer formwork is located on the side opposite to the placing space where concrete is placed as viewed from the inner formwork. This formwork structure has a convex member fixed to the outer formwork, and the convex member protrudes from the through hole into the placing space. With the convex member protruding from the through hole of the inner formwork into the placing space, the convex member is pressed against the inner formwork and the gap between the convex member and the inner formwork is sealed. When concrete is placed in the placing space, mortar or the like does not enter the gap between the convex member and the inner formwork. Also, mortar or the like does not leak out from the outer formwork to which the convex member is fixed. Therefore, the labor for the subsequent finishing can be reduced. Furthermore, since concrete is not placed on the outer formwork and the portion of the convex member fixed to the outer formwork, the attachment and detachment of the convex member to the outer formwork can be made unnecessary. Therefore, the preparation and installation of the formwork structure can be easily performed, and the workability of the preparation and installation can be improved.

[0011] The convex member may have a tapered portion whose cross-sectional area when cut along a plane extending along the inner formwork becomes smaller as it is separated from the outer formwork. In this case, a tapered portion can be formed in the concave portion of the concrete member formed by the convex member.

[0012] The convex member may be made of an elastic material. In this case, since the convex member protruding into the placing space is made of an elastic material, the restraint due to the shrinkage of the placed concrete material is released by the deformation of the convex member made of the elastic material. Therefore, it is possible to suppress the cracking accompanying the shrinkage of the concrete material caused by the convex member acting as a restraint body, and thus the quality of the concrete member can be improved.

[0013] The convex member may form a concave portion of the flange portion of the concrete member, and the inner formwork may form a convex portion of the flange portion. In this case, a concrete member having a flange portion with a concave portion and a convex portion can be manufactured by the formwork structure.

[0014] The manufacturing method of the concrete member according to the present disclosure includes a step of installing an inner formwork that is plate-shaped and has a through hole penetrating in the plate thickness direction to define a placement space where concrete is placed, a step of protruding a convex member into the placement space through the through hole of the inner formwork and through a convex member fixed to the outer formwork, a step of installing a spacing maintaining member that maintains the spacing between the inner formwork and the outer formwork between the inner formwork and the outer formwork in a state where the convex member protrudes into the placement space, and a step of placing concrete into the placement space.

[0015] In this manufacturing method of the concrete member, an inner formwork that is plate-shaped is installed to define a placement space where concrete is placed, and a convex member fixed to the outer formwork is protruded into the placement space through the through hole of the inner formwork. The convex member is protruded into the placement space from the through hole of the inner formwork, and concrete is placed into the placement space while installing a spacing maintaining member to maintain the spacing between the inner formwork and the outer formwork. At this time, since the convex member is pressed against the inner formwork and concrete is placed into the placement space where the gap between the convex member and the inner formwork is sealed, mortar or the like does not enter the gap between the convex member and the inner formwork. Also, mortar or the like does not leak out to the outer formwork to which the convex member is fixed. Therefore, the labor for the subsequent finishing can be reduced. Further, since concrete is not placed on the outer formwork and the portion of the outer formwork to which the convex member is fixed, the attachment and detachment of the convex member to the outer formwork can be made unnecessary. Therefore, the preparation and installation of the inner formwork and the outer formwork can be easily performed, and the workability of the preparation and installation can be improved.

Effects of the Invention

[0016] According to the present disclosure, the workability of the preparation and installation can be improved.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the formwork structure and the method for manufacturing a concrete member according to the present disclosure will be described with reference to the drawings. The same or corresponding elements in the description of the drawings are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate. In addition, the drawings may be drawn with some parts simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those described in the drawings.

[0019] The formwork structure 1 (see FIG. 4) according to the present embodiment is used when manufacturing the concrete member C. FIG. 1 is a plan view showing the concrete member C. As shown in FIG. 1, the concrete member C is precast concrete and is manufactured, for example, in a factory.

[0020] FIG. 2 is a side view of the concrete member C seen along the short side direction D2. As shown in FIGS. 1 and 2, for example, the concrete member C is a precast concrete floor slab. In plan view, the concrete member C has a rectangular shape having a pair of long sides C1 extending in the longitudinal direction D1 and a pair of short sides C2 extending in the short side direction D2. The concrete member C has a plurality of through holes C3 penetrating in the plate thickness direction D3 of the concrete member C.

[0021] A displacement stopper (for example, a headed stud) protruding upward from the main girder on which the concrete member C is placed is passed through the through hole C3. The concrete member C is, as an example, a floor slab constituting a road surface, and is installed such that the short side direction D2 coincides with the bridge axis direction and the longitudinal direction D1 coincides with the direction perpendicular to the bridge axis (width direction).

[0022] For example, the concrete member C is composed of fiber-reinforced concrete. As an example, the concrete member C is composed of ultra-high strength fiber-reinforced concrete (UFC). For example, the concrete member C is a UFC floor slab. In this case, since the concrete member C can have high strength, the thickness of the concrete member C can be reduced compared to a concrete member composed of normal concrete.

[0023] The concrete member C has a flange portion C4. For example, the flange portion C4 extends in both the longitudinal direction D1 and the plate thickness direction D3 at the end of the concrete member C in the short side direction D2. For example, a plurality of concrete members C are installed on the main girder so as to be arranged along the short side direction D2 (bridge axis direction), and the flange portion C4 functions as a joint portion. In this case, a caulking material is filled between a pair of flange portions C4 arranged along the short side direction D2. The flange portion C4 has a convex portion C5 that forms the end face of the concrete member C, and a concave portion C6 that is recessed from the convex portion C5 in the short side direction D2. The concave portion C6 functions as a shear key for the joint portion.

[0024] The concrete member C has a plurality of concave portions C6, and the plurality of concave portions C6 are arranged along the longitudinal direction D1 in the flange portion C4. FIG. 3 is an enlarged view of the flange portion C4. As shown in FIGS. 2 and 3, the concave portion C6 is defined by a bottom surface C7 extending in the longitudinal direction D1 and the plate thickness direction D3, and an inclined surface C8 extending from the convex portion C5 to the bottom surface C7.

[0025] When viewed along the short side direction D2, the concave portion C6 and the bottom surface C7 of the concave portion C6, for example, exhibit a rectangular shape. The concave portion C6 has four ridge lines extending from each of the four corners of the bottom surface C7 to the convex portion C5, and four inclined surfaces C8 located between a pair of adjacent ridge lines along the longitudinal direction D1 or the plate thickness direction D3. Each inclined surface C8 is inclined with respect to both the convex portion C5 and the bottom surface C7.

[0026] For example, the concrete member C has a through hole C11 that penetrates the concrete member C in the short side direction D2, and the inner surface of the through hole C11 is formed by a sheath pipe C12. The concrete member C has a plurality of through holes C11. The plurality of through holes C11 are arranged along the longitudinal direction D1. Further, the concrete member C has a plurality of ring sponges C13 between the sheath pipes of two precast floor slabs facing each other at the joint part.

[0027] The configuration of the concrete member C has been described above. However, the configuration of the concrete member is not limited to the concrete member C described above and can be appropriately changed. Next, the formwork structure 1 used when manufacturing the concrete member C will be described. FIG. 4 is a cross-sectional view showing the formwork structure 1. As shown in FIG. 4, the formwork structure 1 includes an inner formwork 2, an outer formwork 3, a convex member 4, and a spacing holding member 5.

[0028] FIG. 5(a) is a plan view showing the inner formwork 2. FIG. 5(b) is a cross-sectional view taken along line A-A of FIG. 5(a). As shown in FIGS. 5(a) and 5(b), the inner formwork 2 is plate-shaped. As an example, the inner formwork 2 is rectangular. The inner formwork 2 is, for example, made of metal. As an example, the inner formwork 2 is made of iron. However, the material of the inner formwork 2 is not particularly limited.

[0029] The inner formwork 2 is a rectangular plate having a long side 2b extending in the longitudinal direction A1 of the inner formwork 2 and a short side extending in the short side direction A2 of the inner formwork 2, and having a thickness in the plate thickness direction A3. The longitudinal direction A1 coincides with the longitudinal direction D1 of the concrete member C, and the short side direction A2 coincides with the plate thickness direction D3 of the concrete member C. As an example, the short side direction A2 is the vertical direction. The plate thickness direction A3 coincides with the short side direction D2 of the concrete member C.

[0030] For example, the inner formwork 2 is a flange formwork that forms the flange part C4 of the concrete member C. The inner formwork 2 has a through hole 2d penetrating in the plate thickness direction A3. The through hole 2d is a hole through which the convex member 4 is passed in the plate thickness direction A3. The inner formwork 2 has a plurality of through holes 2d, and the plurality of through holes 2d are arranged along the longitudinal direction A1.

[0031] When viewed along the plate thickness direction A3, the through hole 2d has, for example, a rectangular shape (a rectangular shape as an example). The cross-sectional shape when the inner formwork 2 is cut by a plane extending in the short side direction A2 and the plate thickness direction A3 has, for example, a rectangular shape. The through hole 2d is defined by a plurality (four) of inner surfaces 2f of the inner formwork 2. In the cross-section of the inner formwork 2 cut by a plane extending in the longitudinal direction A1 and the plate thickness direction A3, the inner surface 2f is inclined with respect to the plate thickness direction A3.

[0032] The area of the through hole 2d viewed from one side in the plate thickness direction A3 is smaller than the area of the through hole 2d viewed from the other side in the plate thickness direction A3. The inner formwork 2 has a first surface 2g where the area of the through hole 2d is small, and a second surface 2h that faces the side opposite to the first surface 2g and where the area of the through hole 2d is larger than the area of the first surface 2g on the first surface 2g. A concrete placing space S is formed on the surface of the inner formwork 2 on the side of the first surface 2g.

[0033] The outer formwork 3 is provided on the side opposite to the placing space S when viewed from the inner formwork 2. The outer formwork 3 does not define the placing space S and is separated from the placing space S. The outer formwork 3 has, for example, a plate shape. As an example, the outer formwork 3 has a rectangular shape. For example, the outer formwork 3 is made of metal and is composed of iron as an example. However, the material of the outer formwork 3 is not particularly limited. For example, the outer formwork 3 may be composed of a resin material that thermosets. Also, the shape of the outer formwork 3 may be a shape other than a plate shape and is not particularly limited.

[0034] The outer formwork 3 has a hole portion 3b that penetrates in the plate thickness direction A3. The hole portion 3b is a hole through which the spacing holding member 5 is passed in the plate thickness direction A3. The outer formwork 3 has, for example, a plurality of hole portions 3b, and the plurality of hole portions 3b are arranged along the longitudinal direction A1. The outer formwork 3 has a first surface 3c facing the inner formwork 2 side and a second surface 3d facing the side opposite to the first surface 3c.

[0035] The convex member 4 is fixed to, for example, the first surface 3c of the outer mold frame 3. The convex member 4 may be detachable from the outer mold frame 3. As an example, the convex member 4 is fixed to the outer mold frame 3 by an adhesive. The convex member 4 is made of an elastic material. For example, the material of the convex member 4 is rubber. The convex member 4 may be made of a material containing urethane. For example, the convex member 4 has a base portion 4b fixed to the outer mold frame 3 and a tapered portion 4c located on the side opposite to the outer mold frame 3 when viewed from the base portion 4b.

[0036] The base portion 4b has, for example, a rectangular parallelepiped shape. The base portion 4b is arranged to protrude from the outer mold frame 3, and the tapered portion 4c is provided at the protruding end of the base portion 4b. The cross-sectional area when the tapered portion 4c is cut by a plane extending in the longitudinal direction A1 and the short-side direction A2 becomes smaller as it is separated from the base portion 4b. That is, the tapered portion 4c is inclined so as to taper.

[0037] For example, when viewed along the plate thickness direction A3, the shape of the base portion 4b and the shape of the tapered portion 4c are similar to the shape of the through hole 2d of the inner mold frame 2. The tapered portion 4c has, for example, a truncated pyramid shape (a truncated square pyramid shape as an example). The tapered portion 4c has a plurality (four as an example) of tapered surfaces 4d and a top surface 4f.

[0038] The tapered surface 4d is inclined with respect to the direction in which the base portion 4b protrudes from the outer mold frame 3. For example, the inclination angle of the tapered surface 4d is the same as the inclination angle of the inner surface 2f with respect to the plate thickness direction A3 of the inner mold frame 2. In this case, the convex member 4 can be smoothly inserted into the inner surface 2f, and it is possible to suppress the generation of a gap between the convex member 4 and the inner mold frame 2 in a state where the convex member 4 is inserted into the inner surface 2f.

[0039] For example, the shape of the top surface 4f is similar to the shape of the through hole 2d of the inner mold frame 2. When viewed along the plate thickness direction A3, the area of the through hole 2d is larger than the area of the top surface 4f and smaller than the area of the base portion 4b. Therefore, when the tapered portion 4c is inserted into the through hole 2d from the second surface 2h of the inner mold frame 2, the tapered surface 4d contacts the inner surface 2f of the through hole 2d, and a part of the tapered portion 4c protrudes toward the placing space S side.

[0040] The spacing maintaining member 5 maintains the spacing between the inner formwork 2 and the outer formwork 3 in a state where the convex member 4 protrudes into the placing space S. The formwork structure 1 includes, for example, a plurality of spacing maintaining members 5, and the plurality of spacing maintaining members 5 are arranged side by side along the longitudinal direction A1. Further, the plurality of spacing maintaining members 5 are arranged side by side along the short-side direction A2. The spacing maintaining member 5 is, as an example, made of metal. For example, the spacing maintaining member 5 has a cylindrical portion 5b in which an internal thread is formed, and a bolt 5c screwed into the cylindrical portion 5b.

[0041] The cylindrical portion 5b is a portion that abuts against the second surface 2h of the inner formwork 2. The bolt 5c has a threaded portion 5d inserted through the hole portion 3b of the outer formwork 3 and a head portion 5f that abuts against the outer formwork 3. The threaded portion 5d is inserted through the hole portion 3b from the second surface 3d side and screwed into the internal thread of the cylindrical portion 5b, and the head portion 5f abuts against the second surface 3d. Thereby, the spacing between the inner formwork 2 and the outer formwork 3 is maintained by the spacing maintaining member 5.

[0042] Next, a method for manufacturing a concrete member according to the present embodiment will be described. Hereinafter, a method for manufacturing a concrete member C using the formwork structure 1 will be described. First, the inner formwork 2, the outer formwork 3, the convex member 4, and the spacing maintaining member 5 are prepared (preparation step). At this time, the convex member 4 is fixed to the outer formwork 3 by attaching the base portion 4b of the convex member 4 to the outer formwork 3 (step of fixing the convex member). Specifically, a plurality of convex members 4 are fixed to the first surface 3c of the outer formwork 3 so as to be arranged side by side in the longitudinal direction A1.

[0043] Further, an inner formwork 2 is installed to define a placement space S where concrete is to be placed (a step of defining the placement space). At this time, the inner formwork 2 is installed such that the first surface 2g faces the placement space S side and the second surface 2h faces the side opposite to the placement space S. Then, the tapered portion 4c of the convex member 4 is inserted into the through hole 2d of the inner formwork 2, and the convex member 4 is pressed against the through hole 2d so that a part of the convex member 4 protrudes into the placement space S (a step of protruding the convex member). Specifically, the tapered portion 4c of the convex member 4 is inserted into the through hole 2d of the inner formwork 2 from the side opposite to the placement space S, and the tapered surface 4d of the tapered portion 4c is brought into contact with the inner surface 2f of the through hole 2d.

[0044] Subsequently, a spacing maintaining member 5 is installed to maintain the spacing between the inner formwork 2 and the outer formwork 3 (a step of installing the spacing maintaining member). For example, a plurality of spacing maintaining members 5 arranged along the longitudinal direction A1 are installed. At this time, for example, the cylindrical portion 5b of the spacing maintaining member 5 is fixed to the second surface 2h of the inner formwork 2 so as to be resistant to tension, a bolt 5c is inserted through the hole portion 3b of the outer formwork 3, and the bolt 5c inserted through the hole portion 3b is tightened to the female screw of the cylindrical portion 5b to install the spacing maintaining member 5.

[0045] After installing the spacing maintaining member 5, concrete is placed in the placement space S (a step of placing concrete). Although concrete material shrinkage may occur when placing concrete, the restraint due to the material shrinkage is released by the deformation of the convex member 4 constituted by an elastic member.

[0046] After the placed concrete has hardened, the formwork structure 1 is removed (a step of removing the formwork structure). Specifically, the spacing maintaining member 5 is removed by loosening the bolt 5c of the spacing maintaining member 5 and pulling it out from the cylindrical portion 5b. Then, the convex member 4 is pulled out from the through hole 2d of the inner formwork 2, and the convex member 4 and the outer formwork 3 are removed from the inner formwork 2. Note that the convex member 4 may or may not be removed from the outer formwork 3. Further, the inner formwork 2, the outer formwork 3, the convex member 4, and the spacing maintaining member 5 may be removed from the hardened concrete in an integrated state.

[0047] When the formwork structure 1 is removed as described above, a concrete member C is completed in which a concave portion C6 is formed at the portion where the convex member 4 protruded from the through hole 2d, and a convex portion C5 is formed at the portion of the first surface 2g of the inner formwork 2, and a series of steps of the manufacturing method of the concrete member C are completed. Note that the removed inner formwork 2, outer formwork 3, and convex member 4 can be diverted for the manufacture of other concrete members.

[0048] Next, the effects obtained from the formwork structure 1 and the manufacturing method of the concrete member C according to the present embodiment will be described in more detail. The formwork structure 1 and the manufacturing method of the concrete member C according to the present embodiment have a plate-shaped inner formwork 2 and an outer formwork 3, and the distance between the inner formwork 2 and the outer formwork 3 is held by a distance holding member 5. The inner formwork 2 has a through hole 2d penetrating in the plate thickness direction A3 thereof. The outer formwork 3 is located on the side opposite to the placement space S where the concrete is placed as viewed from the inner formwork 2.

[0049] The formwork structure 1 has a convex member 4 fixed to the outer formwork 3, and the convex member 4 protrudes from the through hole 2d into the placement space S. Since the convex member 4 is in close contact with the through hole 2d of the inner formwork 2 and the concrete is placed in the placement space S with the convex member 4 protruding into the placement space S, mortar or the like does not enter the gap between the convex member 4 and the inner formwork 2. Further, mortar or the like does not leak to the outer formwork 3 side. Therefore, the labor of post-finishing for removing foreign matters such as mortar can be reduced. That is, as long as fibers or the like do not enter the gap between the through hole 2d of the inner formwork 2 and the convex member 4, the above post-finishing can be made unnecessary. Further, since the concrete is not placed on the outer formwork 3 and the portion (for example, the base portion 4b) of the convex member 4 fixed to the outer formwork 3, the attachment and detachment of the convex member 4 to the outer formwork 3 can be made unnecessary. Therefore, the preparation and installation of the formwork structure 1 can be easily performed, and the workability of the preparation and installation can be improved.

[0050] In the present embodiment, the convex member 4 has a tapered portion 4c in which the cross-sectional area of the convex member 4 when cut along a plane extending along the inner formwork 2 decreases as it separates from the outer formwork 3. Therefore, a tapered portion (for example, an inclined surface C8 and a ridge line) can be formed in the concave portion (for example, the concave portion C6) of the concrete member C formed by the convex member 4.

[0051] In the present embodiment, the convex member 4 is made of an elastic material. Therefore, since the convex member 4 protruding into the placing space S is made of an elastic material, the restraint due to the shrinkage of the placed concrete material is released by the deformation of the convex member 4 made of the elastic material. Thus, the cracking associated with the shrinkage of the concrete material caused by the convex member 4 acting as a restraint body can be suppressed, so that the quality of the concrete member can be improved.

[0052] The above effects will be described more specifically. FIGS. 6(a) and 6(b) are cross-sectional views showing formwork structures 101 and 201 according to a conventional comparative example. As shown in FIG. 6(a), the formwork structure 101 is a steel formwork and has a flat portion 102 and a plurality of convex portions 103 provided on the flat portion 102. The flat portion 102 and the convex portions 103 are made of steel. In the formwork structure 101, concrete K is placed on the surface where the plurality of convex portions 103 are formed.

[0053] When the concrete K is placed in the formwork structure 101 which is a steel formwork, the convex portion 103 becomes a restraint body due to the shrinkage strain of the concrete K, and cracks X may occur at the corner portions of the concave portions of the concrete K. In particular, cracks X may occur when the concrete K is composed of a material with a large material shrinkage such as UFC.

[0054] As shown in FIG. 6(b), the formwork structure 201 has a flat portion 202 and a plurality of convex portions 203 fixed to the flat portion 202, and the convex portions 203 are made of rubber (silicone). The convex portions 203 are fixed to the flat portion 202 by double-sided tape or bolts or the like. In the case of this formwork structure 201, since the convex portions 203 have high elasticity, the convex portions 203 do not become a restraint body, so the above-mentioned cracks X are suppressed.

[0055] However, in the formwork structure 201, foreign substances such as mortar or fibers may enter between the flat portion 202 and each convex portion 203, so post-finishing may be required after removing the foreign substances. Further, when each convex portion 203 is fixed to the flat portion 202 with a double-sided tape, the convex portion 203 may be attached to the concrete member and may be troublesome to remove. And every time a concrete member is manufactured, it is necessary to fix the convex portion 203 to the flat portion 202.

[0056] Compared with the formwork structure 101 and the formwork structure 201 described above, as shown in FIG. 4, the formwork structure 1 has a configuration in which the convex member 4 is inserted into the through hole 2d of the inner formwork 2, and the convex member 4 is pressed against the inner formwork 2 so that the gap between the convex member 4 and the inner formwork 2 is sealed. Therefore, leakage of mortar or the like from between the inner formwork 2 and the convex member 4 can be suppressed. Accordingly, the labor of post-finishing can be reduced. Further, the outer formwork 3 to which the convex member 4 is fixed is provided at a position separated from the placing space S. For example, even if the convex member 4 is fixed to the outer formwork 3 with a double-sided tape, the double-sided tape is provided at a position away from the concrete member C, so that the formwork structure 1 can be easily removed from the concrete member C. Further, since it is not necessary to remove the convex member 4 from the outer formwork 3 even after the manufacture of the concrete member C is completed, the installation of the formwork structure 1 when manufacturing a new concrete member can be easily performed.

[0057] In the present embodiment, as shown in FIGS. 3 and 4, the convex member 4 forms the concave portion C6 of the flange portion C4 of the concrete member C, and the inner formwork 2 forms the convex portion C5 of the flange portion C4 where the sheath pipe C12 is provided. Therefore, the concrete member C having the flange portion C4 in which the concave portion C6 and the convex portion C5 where the sheath pipe C12 is provided are formed can be manufactured by the formwork structure 1. Further, as described above, since the entry of foreign substances can be suppressed, the finishing of the convex portion C5 and the concave portion C6 can be made clean.

[0058] The embodiments of the formwork structure and the method for manufacturing a concrete member according to the present disclosure have been described above. However, the formwork structure and the method for manufacturing a concrete member according to the present disclosure are not limited to the above-described embodiments, and can be appropriately changed within the scope of the gist described in the claims. That is, the configuration, shape, size, number, material, and arrangement mode of each part of the formwork structure, and the content and order of the steps of the method for manufacturing a concrete member can be appropriately changed within the scope of the above gist.

[0059] For example, in the above-described embodiment, an example in which the shapes of the concave portion C6 and the bottom surface C7 of the concrete member C are rectangular has been described. However, the shapes of the concave portion and the bottom surface of the concrete member may be shapes other than rectangular, for example, circular or oval, and are not particularly limited. Further, in the above-described embodiment, the inner formwork 2 having the through-hole 2d having a rectangular shape has been described. However, the shape of the through-hole of the inner formwork may be a shape other than rectangular, for example, a polygonal shape such as a triangular shape, a circular shape, or an oval shape.

[0060] For example, in the above-described embodiment, the spacing holding member 5 including the cylindrical portion 5b and the bolt 5c has been described. However, the configuration of the spacing holding member may be other than the configuration including the cylindrical portion 5b and the bolt 5c. Thus, the configuration of the spacing holding member can be appropriately changed. Also, the configurations of the inner formwork, the outer formwork, and the convex member can be appropriately changed.

[0061] For example, in the foregoing embodiment, the formwork structure 1 provided with the convex member 4 that forms the concave portion C6 of the flange portion C4 of the concrete member C and the inner formwork 2 that forms the convex portion C5 of the flange portion C4 where the sheath pipe C12 is provided was described. Thus, in the formwork structure 1, it is possible to form the convex portion C5 of the concrete member C by the inner formwork 2 and form the concave portion C6 of the concrete member C by the convex member 4. However, the inner formwork 2 may form convex portions other than the convex portion C5 of the flange portion C4 where the sheath pipe C12 is provided, and the convex member 4 may form concave portions other than the concave portion C6 of the flange portion C4. That is, the formwork structure according to the present disclosure is not limited to the flange portion C4 of the concrete member C, and can be used for producing various irregularities of the concrete member C.

[0062] For example, in the foregoing embodiment, the concrete member C constituted by UFC was described. However, the concrete member may be constituted by a material other than UFC. Further, in the foregoing embodiment, an example of manufacturing the concrete member C in which the formwork structure 1 is a slab constituting a road surface was described. However, the concrete member may be a concrete member other than the slab, and the formwork structure and manufacturing method according to the present disclosure are applicable to various concrete members.

Description of Reference Numerals

[0063] 1... formwork structure, 2... inner formwork, 2b... long side, 2d... through hole, 2f... inner surface, 2g... first surface, 2h... second surface, 3... outer formwork, 3b... hole portion, 3c... first surface, 3d... second surface, 4... convex member, 4b... base portion, 4c... tapered portion, 4d... tapered surface, 4f... top surface, 5... spacing holding member, 5b... cylindrical portion, 5c... bolt, 5d... threaded portion, 5f... head, A1... longitudinal direction, A2... short transverse direction, A3... plate thickness direction, C... concrete member, C1... long side, C2... short side, C3... through hole, C4... flange portion, C5... convex portion, C6... concave portion, C7... bottom surface, C8... inclined surface, C11... through hole, C12... sheath pipe, C13... ring sponge, D1... longitudinal direction, D2... short transverse direction,, D3... plate thickness direction, K... concrete, S... placing space, X... crack.

Claims

1. A formwork structure used for manufacturing a concrete member, an inner formwork presenting a plate shape and having a through hole penetrating in the plate thickness direction, an outer formwork located on the side opposite to the placement space where concrete is placed as viewed from the inner formwork, a convex member fixed to the outer formwork, passed through the through hole, and protruding into the placement space, a spacing maintaining member for maintaining the spacing between the inner formwork and the outer formwork in a state where the convex member protrudes into the placement space, and comprising a formwork structure.

2. The convex member has a tapered portion in which the cross-sectional area of the convex member becomes smaller as it separates from the outer formwork when cut along a plane extending along the inner formwork, The formwork structure according to Claim 1.

3. The convex member is made of an elastic material, The formwork structure according to Claim 1 or 2.

4. The convex member forms a recess in the flange portion of the concrete member, The inner formwork forms a convex portion in the flange portion, The formwork structure according to Claim 1 or 2.

5. A step of installing an inner formwork presenting a plate shape and having a through hole penetrating in the plate thickness direction to define a placement space where concrete is placed, A step of passing a convex member fixed to an outer formwork through the through hole of the inner formwork and protruding the convex member into the placement space, A step of installing a spacing maintaining member for maintaining the spacing between the inner formwork and the outer formwork between the inner formwork and the outer formwork in a state where the convex member protrudes into the placement space, A step of placing concrete in the placement space, and comprising A method for manufacturing a concrete member.

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