Connection structure

Abstract

To provide a connection structure capable of shortening a gap filler width than conventional ones while keeping connection performance for the connection structure of a reinforcement concrete member.SOLUTION: A connection structure is configured to form a projected part 12 having an uneven shape by burying reinforcement bars 11 extending in a direction of a connection axis of reinforcement concrete members 1A, 1B at a connection end of the reinforcement member 1A using fiber-reinforced cement composite material, to project a joint reinforcement bar 13 projecting from a connection end of the reinforcement member 1B facing the reinforcement concrete member 1A, and to arrange the joint reinforcement bar 13 of the reinforcement concrete member 1B in a concave part of the projected part 12 of the reinforcement concrete member 1A, wherein the connection end of the reinforcement concrete member 1A and the connection end of the reinforcement member 1B is bonded by gap filler 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a joint structure for reinforced concrete members. [Background technology]

[0002] Generally, when joining reinforced concrete members, it is necessary to resist tensile forces acting on the joint surface. Conventionally, this has required joints to connect the reinforcing bars to resist tensile forces, or prestressing the joint surface to prevent tensile forces from acting on it.

[0003] Furthermore, as a method for joining reinforced concrete members, for example, Patent Document 1 discloses an invention in which a convex multi-stage shear key is formed at the end of a precast concrete deck, providing adhesion resistance and shear resistance between the joint and the concrete poured at the connection, thereby increasing the rigidity of the connection.

[0004] Furthermore, Patent Document 2 discloses an invention in which unevenness is formed at the end of a precast concrete deck in a direction perpendicular to the bridge axis, thereby improving resistance to the tensile force generated at the end of the precast concrete deck. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6988189 [Patent Document 2] Japanese Patent Application Publication No. 2019-183425 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as can be seen from the figures in the above patent documents, the width of the joint is determined by the length of the lap joint of the reinforcing bars, so it is not possible to narrow the filling width at the joint. Therefore, the large filling width poses challenges in reducing the labor required to pour filling material and material costs.

[0007] Therefore, in consideration of the above-mentioned problems, the present invention aims to provide a joint structure for reinforced concrete members that can reduce the gap width more than conventionally while maintaining joint performance. [Means for solving the problem]

[0008] The invention pertaining to (1) is a joint structure for reinforced concrete members that are spaced apart and facing each other, wherein a protruding portion having an uneven shape is formed at the joint end of one of the reinforced concrete members by embedding a reinforcing bar extending in the connecting axis direction of the reinforced concrete member with a fiber-reinforced cement-based composite material, and a joint reinforcing bar protruding from the joint end of the other reinforced concrete member facing the one reinforced concrete member is protruding, and the joint reinforcing bar of the other reinforced concrete member is placed in a recess of the protruding part of the one reinforced concrete member, and the joint end of the one reinforced concrete member and the joint end of the other reinforced concrete member are bonded together with filler material.

[0009] The invention related to (2) is the connection structure described in (1) above, characterized in that the root portion of the joint reinforcing bar protruding from the joint end portion of the other reinforced concrete member is embedded in a fiber-reinforced cement-based composite material and has an uneven shape in the direction of the connection axis.

[0010] The invention related to (3) is the joint structure described in (1) above, characterized in that the recess of the protrusion formed at the joint end of one of the reinforced concrete members is an insertion hole into which a joint reinforcing bar protruding from the joint end of the other reinforced concrete member can be inserted.

[0011] The invention according to (4) is a joint structure described in any one of (1) to (3) above, characterized in that at least one of the one reinforced concrete member and the other reinforced concrete member is equipped with a pretensioning member.

[0012] The inventions according to (5) and (6) are the joint structures according to any one of (1) to (4) above, characterized in that the filler is a fiber-reinforced cement-based composite material. [Effects of the Invention]

[0013] The joint structure of the present invention allows the width of the filler at the joint of reinforced concrete members to be narrowed while maintaining the performance of the reinforcing bar joint, thereby improving the workability of the joint and reducing the labor and material costs required for pouring the filler material. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a plan perspective view of a first embodiment of the present invention, showing the arrangement of reinforced concrete members before joining. [Figure 2] FIG. 1 is a plan perspective view of a first embodiment of the present invention, showing the arrangement of reinforced concrete members after joining. [Figure 3] 1A and 1B show a first embodiment of the present invention, in which (a) is a cross-sectional view taken along line AA in FIG. 1 and (b) is a cross-sectional view taken along line AA in FIG. [Figure 4] 1A and 1B show a first embodiment of the present invention, in which (a) is a cross-sectional view taken along line BB in FIG. 1 and (b) is a cross-sectional view taken along line BB in FIG. [Figure 5] FIG. 10 is a plan perspective view of a second embodiment of the present invention, showing the arrangement of reinforced concrete members before joining. [Figure 6] FIG. 10 is a plan perspective view of a second embodiment of the present invention, showing the arrangement of reinforced concrete members after joining. [Figure 7] 5A and 5B show a second embodiment of the present invention, in which (a) is a cross-sectional view taken along line AA in FIG. 5, and (b) is a cross-sectional view taken along line AA in FIG. [Figure 8] 6A and 6B show a second embodiment of the present invention, in which (a) is a cross-sectional view taken along line BB in FIG. 5 and (b) is a cross-sectional view taken along line BB in FIG. [Figure 9] FIG. 10 is a perspective view of a third embodiment of the present invention, showing the arrangement of reinforced concrete members before joining. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, various embodiments of the joint structure of the present invention will be described with reference to the drawings. The joint structure of the present invention is intended for a joint structure of reinforced concrete members arranged opposite each other, and can be applied to, for example, not only road bridges but also railway facilities, port facilities, decks installed in tunnels, joint structures for precast concrete decks in buildings, and joint structures for various other structural materials. The following description will be given using a precast concrete deck as an example.

[0016] (First embodiment) Fig. 1 shows a first embodiment of the present invention, in a plan perspective view, the arrangement of reinforced concrete members 1A and 1B before joining, while Fig. 2 shows a plan perspective view, the arrangement of reinforced concrete members 1A and 1B after joining.

[0017] As shown in the figure, the joint structure of this embodiment is a joint structure for reinforced concrete members 1A and 1B that are opposed to and spaced apart from each other, and at the joint end of one of the reinforced concrete members 1A, a protruding portion 12 having an uneven shape is formed by embedding a reinforcing bar 11 extending in the connecting axis direction of the reinforced concrete members 1A and 1B using a fiber-reinforced cement-based composite material, and at the joint end of the other reinforced concrete member 1B that faces the one of the reinforced concrete members 1A, a joint reinforcing bar 13 protrudes from the joint end, and the joint reinforcing bar 13 of the other reinforced concrete member 1B is placed in the recess of the protruding portion 12 of the one of the reinforced concrete members 1A, and the joint end of the one of the reinforced concrete members 1A and the joint end of the other of the reinforced concrete member 1B are bonded together by a filler material 2.

[0018] Figure 3(a) shows the AA cross section of Figure 1, and Figure 4(a) shows the BB cross section of Figure 1. As shown in the figures, one reinforced concrete member 1A and the other reinforced concrete member 1B are arranged facing each other with a gap between them. At the joint end of one reinforced concrete member 1A, a reinforcing bar 11 is embedded in a fiber-reinforced cementitious composite material to form a protruding portion 12 with an uneven shape.

[0019] 1 and 2, the protrusion 12 of this embodiment has a wedge shape when viewed from above. However, the protrusion 12 is not necessarily limited to a wedge shape, and it is also possible to provide a U-shaped protrusion or recess (not shown).

[0020] Furthermore, the fiber reinforced cement composite material of this embodiment is not limited to a specific type, but as a more preferred fiber reinforced cement composite material, ultra-high strength fiber reinforced concrete (hereinafter referred to as "UFC") can be used.

[0021] Furthermore, a joint reinforcing bar 13 protruding from the joint end of the other reinforced concrete member 1B is provided, and the joint reinforcing bar 13 is positioned in the recess of the protruding portion 12 of the one reinforced concrete member 1A.

[0022] In addition, a convex shear key 17 as shown in Patent Document 1 is formed at the joint end of the other reinforced concrete member 1B in this embodiment, which increases the rigidity of the entire connected reinforced concrete members 1A and 1B.

[0023] In this embodiment shown in Figures 1 and 2, as shown, the reinforcing bar 11 embedded in the protruding portion 12 and the joint reinforcing bar 13 protruding from the other reinforced concrete member 1B are overlapped with a width of 75 mm.

[0024] The reinforced concrete member 1A and the other reinforced concrete member 1B arranged as described above are bonded to each other by pouring filler 2 made of fiber-reinforced cementitious composite material, as shown in Figures 2, 3(b), and 4(b).

[0025] In this embodiment, a fiber reinforced cement composite material is used as the filler material 2. The fiber reinforced cement composite material is not limited to a specific type, but more preferably, ultra-high strength fiber reinforced concrete (hereinafter referred to as "UFC") can be used.

[0026] The UFC is a lightweight, high-strength, and highly durable concrete material containing steel fibers and other materials. UFC has tensile strength four to five times higher than conventional high-strength concrete, and its bond strength is 1.5 to 2 times higher. Therefore, by using the UFC as filler 2, it is possible to obtain high rigidity and bending strength through the synergistic effect of suppressing the opening of the construction joints and the high tensile strength and high shear strength of the UFC.

[0027] In this embodiment, room temperature curing UFC is used as an example, which has excellent watertightness and airtightness, as well as excellent fluidity and filling properties, and can be poured and cured on-site. However, the present invention is not limited to room temperature curing UFC, and UFC with various specifications and formulations can be used.

[0028] According to the joint structure of the first embodiment described above, it is possible to narrow the width of the filler at the joint between the reinforced concrete members 1A and 1B while improving stress transmission through the reinforcing bars, which improves workability at the joint and reduces the labor and material costs required for pouring the filler material.

[0029] (Second embodiment) Next, Fig. 5 shows a second embodiment of the present invention, in a plan perspective view, the arrangement of reinforced concrete members 1A and 1B before joining, while Fig. 6 shows a plan perspective view, the arrangement of reinforced concrete members 1A and 1B after joining.

[0030] As shown in the figure, the joint structure of this embodiment differs from the first embodiment described above in that the base portion of the joint reinforcing bar 13 protruding from the joint end portion of the other reinforced concrete member 1B is embedded in the fiber-reinforced cement-based composite material and has an uneven portion 15 in the connection axis direction.

[0031] With this configuration, the joint ends of the opposing reinforced concrete members 1A and 1B are made of fiber-reinforced cement-based composite material, and are therefore firmly bonded to the filler material 2 made of fiber-reinforced cement-based composite material, thereby increasing the rigidity of the entire connected reinforced concrete members 1A and 1B.

[0032] 5 and 6, in this embodiment, the uneven portion 15, which is the joint end portion at the base of the joint reinforcing bar 13, is wedge-shaped when viewed from above. This allows it to be firmly integrated with the filler material 2. Note that the joint end portion is not necessarily limited to a wedge shape, and it is also possible to provide a U-shaped uneven portion (not shown).

[0033] Figure 7(a) shows the AA cross section of Figure 5, and Figure 8(a) shows the BB cross section of Figure 5. As shown in the figures, one reinforced concrete member 1A and the other reinforced concrete member 1B are arranged facing each other with a gap between them. At the joint end of one reinforced concrete member 1A, a reinforcing bar 11 is embedded in a fiber-reinforced cementitious composite material to form a protruding portion 12 with an uneven shape.

[0034] 5 and 6, the protrusion 12 of this embodiment has a wedge shape when viewed from above. However, the protrusion 12 is not necessarily limited to a wedge shape, and it is also possible to provide a U-shaped protrusion or recess (not shown).

[0035] Furthermore, the fiber reinforced cement composite material of this embodiment is not limited to a specific type, but more preferably, ultra-high strength fiber reinforced concrete (hereinafter referred to as "UFC") can be used.

[0036] Furthermore, as described above, a joint reinforcing bar 13 protrudes from the joint end of the other reinforced concrete member 1B, and its base is embedded in fiber-reinforced cement-based composite material.

[0037] In the second embodiment shown in Figures 5 and 6, as shown, the reinforcing bar 11 embedded in the protruding portion 12 and the joint reinforcing bar 13 protruding from the other reinforced concrete member 1B are overlapped with a width of 75 mm.

[0038] The reinforced concrete members 1A and 1B arranged as described above are bonded to each other by pouring filler 2 made of fiber-reinforced cementitious composite material, as shown in Figures 6, 7(b), and 8(b).

[0039] In this embodiment, a fiber reinforced cement composite material is also used as the filler material 2. The fiber reinforced cement composite material is not limited to a specific type, but more preferably, ultra-high strength fiber reinforced concrete (hereinafter referred to as "UFC") can be used.

[0040] In this embodiment, at least one of the reinforced concrete member 1A and the other reinforced concrete member 1B is configured to include a pretension member 14.

[0041] More specifically, as shown in Figures 5 and 6, both ends of reinforced concrete members 1A and 1B are made of fiber-reinforced cementitious composite material, and tension is introduced by pretensioning members 14 made of PC steel strands. This makes it possible to effectively suppress a decrease in the transmission of tension due to the excellent bond performance of the fiber-reinforced cementitious composite material. It is more preferable to use UFC as the fiber-reinforced cementitious composite material.

[0042] According to the joint structure of the second embodiment as described above, in addition to the effects obtained by the first embodiment described above, the rigidity of the entire reinforced concrete members 1A, 1B to be connected can be further increased.

[0043] (Third embodiment) Next, FIG. 9 shows a perspective view of the arrangement of reinforced concrete members before joining according to a third embodiment of the present invention.

[0044] As shown in the figure, in the joint structure of this embodiment, the recess of the protrusion portion 12 formed at the joint end of one reinforced concrete member 1A is formed with an insertion hole 16 into which a joint reinforcing bar 13 protruding from the joint end of the other reinforced concrete member 1B can be inserted.

[0045] When joining reinforced concrete members 1A and 1B, filler 2 made of fiber-reinforced cementitious composite material is filled into the insertion holes 16, and joint reinforcing bars 13 are inserted into the insertion holes 16 as shown by the arrows in the figure, and joined together. Preferably, UFC can be used as the filler 2, but other types of materials can also be used as the filler 2 as long as sufficient adhesive strength can be obtained.

[0046] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments.

[0047] For example, it is possible to roughen the joint ends of reinforced concrete members 1A and 1B. This increases the amount of short fibers that will bridge with the filler material 2 that will be poured later, and also makes it possible to ensure that these fibers are longer. This effect further improves the adhesion resistance and shear resistance with the filler material 2, suppresses cracking and gaps at the joints, and increases the rigidity of the joints.

[0048] In addition, although the drawings of each embodiment show specific dimensions, reinforcement pitch, etc., they are not necessarily limited to these dimensions and reinforcement arrangements, and can be designed as appropriate.

[0049] The scope of the present invention is defined by the claims rather than the above description of the embodiments, and includes all modifications within the meaning and scope of the claims. The specific materials, dimensions, shapes, etc. described in the above examples can be modified within the scope of solving the problems of the present invention. [Explanation of symbols]

[0050] 1A One of the reinforced concrete members 1B The other reinforced concrete member 2. Filling material 11 Reinforced concrete 12 Protruding part 13 Reinforced concrete joints 14 Pretensioning member 15 Uneven part 16 Insertion hole 17 Convex shear key

Claims

1. A joint structure for reinforced concrete members facing each other and spaced apart, At the joint end of one of the reinforced concrete members, a protruding portion having an uneven shape is formed by embedding a reinforcing bar extending in the connecting axis direction of the reinforced concrete member with a fiber-reinforced cement-based composite material, A joint reinforcing bar is provided at a joint end of the other reinforced concrete member facing the one reinforced concrete member, and protrudes from the joint end, The joint reinforcing bar of the other reinforced concrete member is placed in the recess of the protruding portion of the one reinforced concrete member, and the joint end of the one reinforced concrete member and the joint end of the other reinforced concrete member are bonded together with a filler material. A joining structure characterized by:

2. The root portion of the joint reinforcing bar protruding from the joint end portion of the other reinforced concrete member is embedded in a fiber-reinforced cement-based composite material and has an uneven shape in the connection axis direction. The connection structure according to claim 1 .

3. The recess of the protruding portion formed at the joint end of the one reinforced concrete member is an insertion hole into which a joint reinforcing bar protruding from the joint end of the other reinforced concrete member can be inserted. The joining structure according to claim 1 .

4. At least one of the one reinforced concrete member and the other reinforced concrete member is provided with a pretensioning member. The joint structure according to any one of claims 1 to 3.

5. The filler is a fiber-reinforced cement-based composite material. The joint structure according to any one of claims 1 to 3.

6. The filler is a fiber-reinforced cement-based composite material. The joining structure according to claim 4 .

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