Joining structure and joining method

Abstract

To provide a joining structure and a joining method capable of preventing tension from occurring at an upper edge of a joint when performing tensioning by tensioning materials.SOLUTION: A joining structure 40 according to one embodiment comprises a tensioning material 52 that penetrates a first protrusion unit 16 of a first concrete member 10 and a second protrusion unit 26 of a second concrete member 20 in a parallel arrangement direction D4, a filling unit 60 located between a first end surface 11 and a second end surface 21, and a space holding member 70 located at a place between the first end surface 11 and the second end surface 21 and different from the filling unit 60.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a joining structure and a joining method for joining a pair of concrete members to each other.

Background Art

[0002] Patent Document 1 describes a connecting structure for connecting a first precast floor slab and a second precast floor slab to each other. The first precast floor slab has a first end face facing the second precast floor slab and a horizontal hole extending in the horizontal direction from the first end face. The second precast floor slab has a second end face facing the first precast floor slab and a horizontal hole extending in the horizontal direction from the second end face.

[0003] The first precast floor slab further has a notch recess that is located on the side opposite to the first end face when viewed from the horizontal hole and is recessed from the upper surface of the first precast floor slab. The notch recess communicates with the horizontal hole. A prestress introduction device is disposed in the horizontal hole of the first precast floor slab, the notch recess, and the horizontal hole of the second precast floor slab.

[0004] The prestress introduction device includes a hollow PC steel bar disposed in the horizontal hole, a pushing reaction PC steel bar inserted into the hollow PC steel bar, and a pair of anchor materials respectively located at both ends of the hollow PC steel bar. In this prestress introduction device, the hollow PC steel bar is tensioned by pushing the pushing reaction PC steel bar into the hollow PC steel bar.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, a joining structure is known in which a pair of concrete members joined to each other have fixing protrusions that face each other and protrude downward. In this joining structure, a tension member such as a PC steel bar that penetrates the pair of fixing protrusions in the horizontal direction is inserted through the pair of fixing protrusions. The pair of concrete members are integrated by this tension member.

[0007] However, when tension is applied by the above tension member, tension may be generated at the upper edge of the joint portion of the pair of concrete members due to the eccentricity of the arrangement of the tension member with respect to the centroid of the pair of concrete members. In order to suppress the occurrence of this tension, the amount of protrusion downward of the fixing protrusion must be increased. However, if the amount of protrusion downward of the fixing protrusion is increased, it is assumed that the fixing protrusion will contact a member or the like located below the concrete member. From the above, it is required that the occurrence of tension at the upper edge of the joint portion can be suppressed even when tension is applied by the tension member.

[0008] An object of the present disclosure is to provide a joining structure and a joining method capable of suppressing the occurrence of tension at the upper edge of a joint portion when tension is applied by a tension member.

Means for Solving the Problems

[0009] (1) The joining structure according to the present disclosure is a joining structure that joins a first concrete member and a second concrete member along a juxtaposition direction, which is a direction in which a first end face of the first concrete member and a second end face of the second concrete member are juxtaposed. The first concrete member has a first joining portion joined to the second concrete member and a first extending portion extending from the first joining portion in a direction opposite to the second concrete member. The second concrete member has a second joining portion joined to the first concrete member and a second extending portion extending from the second joining portion in a direction opposite to the first concrete member. The first joining portion has a first protruding portion that protrudes vertically downward from a lower surface of the first extending portion. The second joining portion has a second protruding portion that protrudes vertically downward from a lower surface of the second extending portion. The joining structure includes a tension member that penetrates the first protruding portion and the second protruding portion in the juxtaposition direction, a filling portion located between the first end face and the second end face, and a space holding member located between the first end face and the second end face at a location different from the filling portion.

[0010] In this joining structure, the first joining portion of the first concrete member has a first protruding portion that protrudes vertically downward, and the second joining portion of the second concrete member has a second protruding portion that protrudes vertically downward. The first concrete member and the second concrete member are arranged along the juxtaposition direction, and a tension member penetrating in the juxtaposition direction is inserted through the first protruding portion and the second protruding portion. A filling portion is filled and a space holding member is arranged between the first end face of the first concrete member and the second end face of the second concrete member. By arranging the space holding member between the first end face and the second end face, the centroid of the filling portion filled between the first concrete member and the second concrete member can be adjusted. Therefore, the eccentricity of the arrangement of the tension member with respect to the centroids of the first concrete member and the second concrete member can be reduced. As a result, even when the first concrete member and the second concrete member are tensioned by the above-described tension member, it is possible to suppress the occurrence of tension at the upper edge of the joining portion between the first concrete member and the second concrete member.

[0011] (2) In the above (1), the filling part may have a first filling part located vertically above the space holding member and a second filling part located vertically below the space holding member. In this case, since the space holding member is arranged between the first filling part and the second filling part in the vertical direction, the centroid can be lowered, and the tension generated at the upper edge of the joint can be more reliably reduced.

[0012] (3) In the above (1) or (2), the vertical center of the space holding member may be located vertically above the vertical center of the first joint part and vertically above the vertical center of the second joint part. In this case, since the centroids of the first concrete member and the second concrete member can be more reliably lowered, the tension generated at the upper edge of the joint can be more reliably suppressed.

[0013] (4) In any of the above (1) to (3), the space holding member may be constituted by a foam. In this case, the shape and size of the space holding member can be arbitrary. Therefore, since the handling of the space holding member can be facilitated, the joining work of the first concrete member and the second concrete member can be performed more efficiently.

[0014] (5) In any of the above (1) to (4), the space holding member may be a stress transmission suppression member that suppresses the stress transmission from the first concrete member and the second concrete member. The stress transmission suppression member may be provided on each of the first end face and the second end face. In this case, the stress transmission from the first concrete member and the second concrete member can be suppressed by the stress transmission suppression member. Furthermore, since the stress transmission suppression member is provided on each of the first end face and the second end face, the filling part can be passed between the stress transmission suppression member provided on the first end face and the stress transmission suppression member provided on the second end face. Therefore, the stress transmission from the first concrete member and the second concrete member can be suppressed while making the filling part integral up and down.

[0015] (6) The joining method according to the present disclosure is a joining method for joining a first concrete member and a second concrete member along a juxtaposition direction, which is a direction in which a first end face of the first concrete member and a second end face of the second concrete member are juxtaposed. The first concrete member has a first joint portion joined to the second concrete member and a first extending portion extending in a direction opposite to the second concrete member from the first joint portion. The second concrete member has a second joint portion joined to the first concrete member and a second extending portion extending in a direction opposite to the first concrete member from the second joint portion. The first joint portion has a first protruding portion protruding vertically downward from a lower surface of the first extending portion. The second joint portion has a second protruding portion protruding vertically downward from a lower surface of the second extending portion. The joining method includes a step of disposing a space holding member on at least one of the first end face and the second end face, a step of opposing the first end face and the second end face to each other, a step of filling a filling portion between the first end face and the second end face and curing the filling portion, and a step of tensioning the first concrete member and the second concrete member by a tension member penetrating the first protruding portion and the second protruding portion in the juxtaposition direction.

[0016] In this joining method, the first concrete member and the second concrete member are arranged along the juxtaposition direction, and the first end face and the second end face face each other. A tension member penetrating in the juxtaposition direction is inserted through the first protruding portion and the second protruding portion, and a filling portion is filled between the first end face and the second end face. Further, a space holding member is disposed between the first end face and the second end face. By disposing the space holding member between the first end face and the second end face, the centroid of the filling portion filled between the first concrete member and the second concrete member can be adjusted. Therefore, similar to the above-described joining structure, the eccentricity of the arrangement of the tension member with respect to the centroid of the first concrete member and the second concrete member can be reduced. Accordingly, even when tensioning is performed by the tension member, it is possible to suppress the occurrence of tension at the upper edge of the joint portion between the first concrete member and the second concrete member.

[0017] (7) In the above (6), the space holding member may be a stress transmission suppressing member that suppresses the transmission of stress from the first concrete member and the second concrete member. In the step of arranging the space holding member, the stress transmission suppressing member may be arranged on at least one of the first end face and the second end face. In this case, by arranging the stress transmission suppressing member on at least one of the first end face and the second end face, the transmission of stress from the first concrete member and the second concrete member can be suppressed. Further, the transmission of stress from the first concrete member and the second concrete member can be suppressed while making the filling part integral up and down.

Effect of the Invention

[0018] According to the present disclosure, it is possible to suppress the occurrence of tension at the upper edge of the joint portion when tensioning is performed by the tension member.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

[0020] Hereinafter, embodiments of a joining structure and a joining method according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate. The drawings may be partially simplified or schematically drawn for ease of understanding, and the dimensional ratios and the like are not limited to those described in the drawings.

[0021] FIG. 1 is a cross-sectional view schematically showing a concrete structure 1 constructed at a site A to which the joining structure according to the present embodiment is applied. The concrete structure 1 is, for example, a bridge. As shown in FIG. 1, the concrete structure 1 includes a plurality of main girders 2 extending in the bridge axis direction D1 and arranged along an intersection direction D2 intersecting the bridge axis direction D1, a cross girder 3 extending in the intersection direction D2, and a plurality of concrete members 5 arranged so as to extend in the intersection direction D2 on the plurality of main girders 2.

[0022] In the present embodiment, the concrete member 5 is a precast concrete floor slab. The main girder 2 is, for example, a steel girder having an upper flange 2b, a web 2c, and a lower flange 2d. However, the main girder 2 is not limited to a steel girder, and may be, for example, a PC girder.

[0023] For example, the concrete structure 1 includes a pair of wall parapets 4 located at both ends of the intersection direction D2 as viewed from the plurality of concrete members 5. The site A is, for example, a construction site on an expressway. At the site A, for example, renovation work on the concrete member 5 is performed. Each drawing shows the concrete member 5 after the renovation work. The concrete member 5 has a thickness in the thickness direction D3. The thickness direction D3 is a direction intersecting both the bridge axis direction D1 and the intersection direction D2.

[0024] The concrete member 5 is, as an example, composed of high-strength fiber-reinforced concrete. As an example, the concrete member 5 may be composed of UHPFRC (Ultra High Performance Fiber Reinforced cement-based Composites). When the concrete member 5 is composed of UHPFRC, the concrete member 5 can be made to have high strength, so that the steel bars inside the concrete member 5 can be made unnecessary.

[0025] The concrete member 5 may be composed of ultra-high strength fiber-reinforced concrete (UFC:Ultra-high strength Fiber reinforce Concrete). In this case, it becomes possible to further increase the strength of the concrete member 5. As an example, the concrete member 5 is a UFC floor slab composed of UFC. For example, at Site A, a floor slab renewal work of a highway using a UFC floor slab is carried out. As an example, at Site A, the removal of the existing aged floor slab is carried out.

[0026] When the concrete member 5 is a UFC floor slab, it becomes possible to renew it to a lightweight and highly durable concrete member 5. Therefore, when renewing to a new concrete member 5, it becomes possible to eliminate the need for reinforcement of the main girder 2, pier or foundation structure, etc. that support the concrete member 5, which contributes to shortening the construction period and improving seismic resistance by weight reduction.

[0027] FIG. 2 is a perspective view showing a part of the concrete structure 1. As shown in FIG. 2, the plurality of concrete members 5 include a first concrete member 10 located on one side in the intersection direction D2 of the concrete structure 1 and a second concrete member 20 located on the other side in the intersection direction D2 of the concrete structure 1. Hereinafter, when there is no need to distinguish between the first concrete member 10 and the second concrete member 20, they will be collectively described as the concrete member 5.

[0028] At Site A, a half-section floor slab replacement method may be used. In the half-section floor slab replacement method, one of the multiple lanes is restricted and the floor slab of that lane is replaced. In the half-section floor slab replacement method, since the lanes other than one lane can be used as a road where vehicles can travel, it is possible to eliminate the oncoming traffic restriction between the uphill lane and the downhill lane and ensure the traffic volume of automobiles.

[0029] The concrete structure 1 includes a plurality of first concrete members 10 arranged along the bridge axis direction D1, a plurality of second concrete members 20 arranged along the bridge axis direction D1 at adjacent positions in the intersection direction D2 of the first concrete members 10, and an intersection fixing panel 30. FIG. 3 is a cross-sectional view showing the concrete member 5 and the intersection fixing panel 30. FIG. 4 is a perspective view schematically showing the steel materials arranged inside the concrete member 5.

[0030] As shown in FIGS. 2, 3, and 4, the concrete structure 1 has a plurality of intersection fixing panels 30. For example, the positions of the plurality of intersection fixing panels 30 in the bridge axis direction D1 are different from each other, and the positions of the plurality of intersection fixing panels 30 in the intersection direction D2 are different from each other. Thereby, it is possible to suppress the interference of the jack J (described later) with the cross girder 3.

[0031] The concrete structure 1 includes a plurality of post-tensioning steel materials 6, a plurality of pre-tensioning steel materials 7, and a fixing body 8 provided at the end of the post-tensioning steel material 6. For example, the post-tensioning steel material 6 extends in the bridge axis direction D1, and the pre-tensioning steel material 7 extends in the intersection direction D2. The post-tensioning steel material 6 is passed through a sheath pipe 9 (see FIG. 5) embedded in the concrete member 5. The pre-tensioning steel material 7 is embedded in the concrete member 5.

[0032] The cross-fixing panel 30 has a protruding portion 35 that protrudes vertically downward. The protruding portion 35 extends in the crossing direction D2. The protruding portion 35 has a pair of side surfaces 35b arranged in the bridge axis direction D1 and a bottom surface 35c extending in the bridge axis direction D1 between the lower ends of the pair of side surfaces 35b. In the cross-fixing panel 30, the post-tensioning steel material 6 extends obliquely downward. The end of the post-tensioning steel material 6 extending obliquely downward is connected to a fixing body 8 provided on the side surface 35b of the protruding portion 35.

[0033] For example, the fixing body 8 has a cylindrical shape. The fixing body 8 contacts the concrete member 5 (as an example, the cross-fixing panel 30), and the post-tensioning steel material 6 is passed through the inside of the fixing body 8. A jack J is connected to the post-tensioning steel material 6 extending outward from the fixing body 8 to the outside of the concrete member 5. The jack J is arranged, for example, at an adjacent position of the cross girder 3. By the jack J pulling the post-tensioning steel material 6, a tensile force is applied to the plurality of concrete members 5.

[0034] For example, the first concrete member 10 and the second concrete member 20 are arranged side by side along the crossing direction D2. FIG. 5 is a cross-sectional view showing a joint structure 40 in which the first concrete member 10 and the second concrete member 20 are joined to each other. As shown in FIG. 5, the first concrete member 10 has a plurality of pre-tensioning steel materials 7 extending in the crossing direction D2 and a plurality of post-tensioning steel materials 6 extending in the bridge axis direction D1. The plurality of pre-tensioning steel materials 7 are arranged in the thickness direction D3, and the plurality of post-tensioning steel materials 6 are arranged in the crossing direction D2. The post-tensioning steel material 6 is provided between a pair of pre-tensioning steel materials 7 arranged in the thickness direction D3.

[0035] The second concrete member 20 has a plurality of pre-tensioning steel materials 7 and a plurality of post-tensioning steel materials 6. For example, the arrangement of the post-tensioning steel material 6 and the pre-tensioning steel material 7 in the second concrete member 20 is the same as the arrangement of the post-tensioning steel material 6 and the pre-tensioning steel material 7 in the first concrete member 10.

[0036] The first concrete member 10 has a first end face 11 facing the second concrete member 20 and an upper surface 12 extending from the upper end of the first end face 11 in a direction opposite to the second concrete member 20. The second concrete member 20 has a second end face 21 facing the first concrete member 10 and an upper surface 22 extending from the upper end of the second end face 21 in a direction opposite to the first concrete member 10.

[0037] The joining structure 40 connects the first concrete member 10 and the second concrete member 20 to each other along the juxtaposition direction D4 which is the direction in which the first end face 11 and the second end face 21 are juxtaposed. In the present embodiment, the juxtaposition direction D4 coincides with the intersection direction D2. The first concrete member 10 has a first joining portion 13 joined to the second concrete member 20 and a first extending portion 14 extending from the first joining portion 13 in a direction opposite to the second concrete member 20. The second concrete member 20 has a second joining portion 23 joined to the first concrete member 10 and a second extending portion 24 extending from the second joining portion 23 in a direction opposite to the first concrete member 10.

[0038] The first joining portion 13 is formed by the first end face 11, a part of the upper surface 12, a lower surface 13b extending from the lower end of the first end face 11 in a direction opposite to the second concrete member 20, and a side surface 13c extending upward from the end of the lower surface 13b opposite to the second concrete member 20. The first extending portion 14 is formed by the remaining part of the upper surface 12 and the lower surface 15. The first end face 11 extends in both the bridge axis direction D1 and the thickness direction D3, and the upper surface 12 extends in both the bridge axis direction D1 and the intersection direction D2. The lower surface 15 extends in both the bridge axis direction D1 and the intersection direction D2 below the upper surface 12.

[0039] The second joint portion 23 is formed by a second end face 21, a part of the upper face 22, a lower face 23b extending in a direction opposite to the first concrete member 10 from the lower end of the second end face 21, and a side face 23c extending upward from an end of the lower face 23b opposite to the first concrete member 10. The second extending portion 24 is formed by the remaining portion of the upper face 22 and a lower face 25. The second end face 21 extends in both the bridge axis direction D1 and the thickness direction D3, and the upper face 22 extends in both the bridge axis direction D1 and the intersecting direction D2. The lower face 25 extends in both the bridge axis direction D1 and the intersecting direction D2 below the upper face 22.

[0040] The first joint portion 13 has a first protruding portion 16 that protrudes vertically downward from the lower face 15 of the first extending portion 14. The first protruding portion 16 extends along the bridge axis direction D1. The length (thickness) of the first protruding portion 16 in the thickness direction D3 is longer than the length of the first extending portion 14 in the thickness direction D3. For example, the length of the first protruding portion 16 in the thickness direction D3 is 1.6 times or more and 1.7 times or less the length of the first extending portion 14 in the thickness direction D3. As an example, the length of the first protruding portion 16 in the thickness direction D3 is 150 mm, and the length of the first extending portion 14 in the thickness direction D3 is 250 mm.

[0041] The second joint portion 23 has a second protruding portion 26 that protrudes vertically downward from the lower face 25 of the second extending portion 24. The second protruding portion 26 extends along the bridge axis direction D1 at an adjacent position in the intersecting direction D2 of the first protruding portion 16. For example, the length of the second protruding portion 26 in the thickness direction D3 is the same as the length of the first protruding portion 16 in the thickness direction D3, and the length of the second extending portion 24 in the thickness direction D3 is the same as the length of the first extending portion 14 in the thickness direction D3.

[0042] The joint structure 40 includes a sheath pipe 51 that penetrates the first protruding portion 16 and the second protruding portion 26 in the juxtaposed direction D4, a tension member 52 that extends in the juxtaposed direction D4 inside the sheath pipe 51, and a pair of fastening portions 53 that are fastened to both ends of the tension member 52 respectively. For example, the sheath pipe 51 and the tension member 52 extend linearly.

[0043] The first protrusion 16 and the second protrusion 26 are fixing protrusions provided for fixing the tension member 52. The tension member 52 penetrates through the first protrusion 16 and the second protrusion 26 in the juxtaposition direction D4. For example, the tension member 52 is a PC steel bar. The fastening part 53 is, for example, a nut fastened to each of both ends of the tension member 52.

[0044] The joining structure 40 has a filling part 60 located between the first end face 11 and the second end face 21. The portion between the first end face 11 and the second end face 21 in the joining structure 40 is a joining part P that joins the first concrete member 10 and the second concrete member 20 to each other. The filling part 60 is, for example, a cement-based material that has fluidity during filling and hardens after a certain period of time has elapsed since filling. The filling part 60 may be non-shrinking mortar, or it may be placed-in-place UFC or UHPFRC, and various materials can be used as the filling part 60.

[0045] In the joining structure 40, the first protrusion 16 and the second protrusion 26, which are fixing protrusions, are provided, and the first concrete member 10 and the second concrete member 20 are integrated by the tension member 52. By inserting the tension member 52 through the first protrusion 16 and the second protrusion 26 and tensioning the first concrete member 10 and the second concrete member 20, tensioning can be performed locally.

[0046] That is, even when the jack J cannot be arranged at the end in the intersection direction D2 of the concrete structure 1, the jack J can be arranged around the first protrusion 16 and the second protrusion 26 located at the center in the intersection direction D2 of the concrete structure 1 to perform tensioning. However, when tensioning is performed by the tension member 52, tension may be generated at the upper edge of the joining part P due to the eccentricity between the centroid of the cross-section and the arrangement of the tension member 52. For this reason, there has been a problem that a structure that protrudes significantly downward must be adopted as the first protrusion 16 and the second protrusion 26.

[0047] The joining structure 40 has a space holding member 70 that is located between the first end face 11 and the second end face 21 and at a location different from the filling portion 60. In the present embodiment, the occurrence of the above problems is suppressed by the space holding member 70. FIG. 6 is a view of the space holding member 70 as seen along the crossing direction D2. As shown in FIGS. 5 and 6, for example, the joining structure 40 has a plurality of space holding members 70, and the plurality of space holding members 70 are arranged along the bridge axis direction D1. In this case, the filling portion 60 is provided between two space holding members 70 arranged along the bridge axis direction D1 and above and below the space holding member 70.

[0048] The space holding member 70 indicates one that holds air inside. For example, the space holding member 70 is made of a material that does not resist the force (for example, tensile force) generated in the concrete member 5. As an example, the space holding member 70 is made of a foam. In this case, for example, the space holding member 70 is polystyrene foam. When the space holding member 70 is polystyrene foam, the space holding member 70 can be easily obtained, can be formed into an arbitrary shape, and has high handleability. However, the space holding member 70 may be, for example, urethane foam, sponge, or balloon, and the type of the space holding member 70 is not particularly limited.

[0049] For example, the space holding member 70 is attached to the second end face 21 (or the first end face 11). The filling portion 60 has a first filling portion 61 located vertically above the space holding member 70 and a second filling portion 62 located vertically below the space holding member 70. That is, the filling portion 60 is filled and cured above and below the space holding member 70. The center of the space holding member 70 in the vertical direction (for example, the thickness direction D3) is located vertically above the center of the first joining portion 13 in the vertical direction and vertically above the center of the second joining portion 23 in the vertical direction. That is, the space holding member 70 is provided at an upper position on the first end face 11 and the second end face 21.

[0050] FIG. 7 is a cross-sectional view showing a joining structure 80 in which the second concrete member 20 and the cross-fixing panel 30 are joined to each other. Some configurations of the joining structure 80 are the same as some configurations of the joining structure 40 described above. Therefore, in the following description, the same descriptions as those of the joining structure 40 will be appropriately omitted with the same reference numerals.

[0051] The cross-fixing panel 30 has a first end face 31 similar to the first end face 11, an upper face 32 similar to the upper face 12, a first joint portion 33 similar to the first joint portion 13, and a first extending portion 34 similar to the first extending portion 14. The arrangement of the post-tensioning steel 6 and the pre-tensioning steel 7 in the cross-fixing panel 30 is different from that in the first concrete member 10. In the cross-fixing panel 30, for example, the post-tensioning steel 6 is arranged below two pre-tensioning steels 7 arranged along the thickness direction D3. However, the positional relationship between the post-tensioning steel 6 and the pre-tensioning steel 7 is not limited to the above example.

[0052] Similarly, for the second concrete member 20 joined to the cross-fixing panel 30, the post-tensioning steel 6 is arranged below two pre-tensioning steels 7 arranged along the thickness direction D3. The joining structure 80 in which the second concrete member 20 and the cross-fixing panel 30 are joined to each other has been described above. The joining structure in which the first concrete member 10 and the cross-fixing panel 30 are joined to each other has a structure similar to that of the joining structure 80.

[0053] Next, an example of the steps of the joining method according to the present embodiment will be described with reference to FIGS. 5 and 6. The joining method according to the present embodiment is a method of joining the first concrete member 10 and the second concrete member 20 to each other along the juxtaposition direction D4, which is the direction in which the first end face 11 of the first concrete member 10 and the second end face 21 of the second concrete member 20 are juxtaposed.

[0054] First, the first concrete member 10 and the second concrete member 20 are manufactured at the factory. More specifically, the pretensioned steel 7, the sheath pipe 9, and the sheath pipe 51 are arranged inside the formwork. The pretensioned steel 7 is arranged along the intersection direction D2 and is in a state where the pretensioned steel 7 is pulled. Then, the formwork is filled with concrete, and the concrete is placed on the pretensioned steel 7, the sheath pipe 9, and the sheath pipe 51 to manufacture the first concrete member 10 and the second concrete member 20.

[0055] Next, a space holding member 70 is arranged on at least one of the first end face 11 and the second end face 21 (step of arranging the space holding member). For example, a plurality of space holding members 70 cut out in a rectangular shape are prepared, and the plurality of space holding members 70 are attached to the second end face 21 (or the first end face 11) so as to be arranged along the bridge axis direction D1. As an example, the space holding member 70 is attached to either the first end face 11 or the second end face 21 with an adhesive.

[0056] The first concrete member 10 and the second concrete member 20 are arranged on the main girder 2 so that the first end face 11 and the second end face 21 face each other (step of making the first end face and the second end face face each other). At this time, the space holding member 70 is sandwiched between the first end face 11 and the second end face 21.

[0057] Next, a fluid filling portion 60 is filled between the first end face 11 and the second end face 21 with the both ends and the lower portion of the joint portion P between the first end face 11 and the second end face 21 surrounded by a formwork. At this time, the filling portion 60 enters between the plurality of space holding members 70 and the filling portion 60 moves downward, and the joint portion P is filled with the filling portion 60. Then, the filling portion 60 is cured in a state where the height of the filling portion 60 reaches the upper surface 12 of the first concrete member 10 and the upper surface 22 of the second concrete member 20 (step of curing the filling portion).

[0058] After the filling part 60 has hardened, the tension member 52 is passed through the sheath pipe 51. Then, the first concrete member 10 and the second concrete member 20 are tensioned by the tension member 52 that penetrates the first protruding part 16 and the second protruding part 26 in the juxtaposition direction D4 (tensioning step). Specifically, with the tension member 52 in a pulled state, the pulled tension member 52 is fastened to the fastening part 53, thereby tensioning the first concrete member 10 and the second concrete member 20. Through the above steps, a series of steps of the joining method are completed.

[0059] Next, the effects obtained from the joining structure 40 and the joining method according to the present embodiment will be described. In the joining structure 40 and the joining method according to the present embodiment, the first joining part 13 of the first concrete member 10 has the first protruding part 16 that protrudes vertically downward, and the second joining part 23 of the second concrete member 20 has the second protruding part 26 that protrudes vertically downward. The first concrete member 10 and the second concrete member 20 are arranged along the juxtaposition direction D4, and the tension member 52 that penetrates in the juxtaposition direction D4 is inserted through the first protruding part 16 and the second protruding part 26.

[0060] Between the first end face 11 of the first concrete member 10 and the second end face 21 of the second concrete member 20, the filling part 60 is filled and the space holding member 70 is arranged. By arranging the space holding member 70 between the first end face 11 and the second end face 21, the centroid of the filling part 60 filled between the first concrete member 10 and the second concrete member 20 can be adjusted.

[0061] In this embodiment, the position of the center of gravity of the joint structure 40 in the cross section obtained by cutting the first concrete member 10 and the second concrete member 20 in a plane extending in both the thickness direction D3 and the juxtaposition direction D4 can be lowered by inserting the space holding member 70. Therefore, the eccentricity of the arrangement of the tension member 52 with respect to the centroid of the first concrete member 10 and the second concrete member 20 can be reduced. As a result, even when the first concrete member 10 and the second concrete member 20 are tensioned by the tension member 52, it is possible to suppress the occurrence of tension at the upper edge of the joint portion P between the first concrete member 10 and the second concrete member 20.

[0062] In this embodiment, even when tensioning is performed by the tension member 52, it is possible to suppress the occurrence of tension at the upper edge of the joint portion P due to the eccentricity between the centroid of the cross section and the arrangement of the tension member 52. Therefore, it is not necessary to adopt a structure in which the first protrusion 16 and the second protrusion 26 protrude greatly downward, and thus the amount of protrusion of the first protrusion 16 and the second protrusion 26 downward can be reduced.

[0063] As a specific example, when the space holding member 70 is not provided, the length (thickness) of the first protrusion 16 and the second protrusion 26 in the thickness direction D3 needs to be 300 mm, but when the space holding member 70 is provided, this length can be reduced to 250 mm. Further, for the cross-fixing panel 30 and the first concrete member 10 (second concrete member 20) adjacent to the cross-fixing panel 30 in the cross direction D2, when the space holding member 70 is not provided, the thickness of the protrusion needs to be 500 mm, but when the space holding member 70 is provided, the thickness of the protrusion can be reduced to 300 mm.

[0064] In this embodiment, by being able to reduce the thickness of the first protruding portion 16 and the thickness of the second protruding portion 26, the weights of the first concrete member 10 and the second concrete member 20 can be reduced and they can be made compact. Further, by arranging the space holding member 70 between the first end face 11 and the second end face 21, the cross-sectional area of the portions where prestress acts on the first concrete member 10 and the second concrete member 20 during tensioning by the tension member 52 will decrease. Therefore, prestress can be more efficiently applied to the first concrete member 10 and the second concrete member 20.

[0065] In this embodiment, the filling portion 60 has a first filling portion 61 located vertically above the space holding member 70 and a second filling portion 62 located vertically below the space holding member 70. In this case, since the space holding member 70 is arranged between the first filling portion 61 and the second filling portion 62 in the vertical direction, the centroid can be lowered and the tension generated at the upper edge of the joint portion P can be more reliably reduced.

[0066] In this embodiment, the vertical center of the space holding member 70 is located vertically above the vertical center of the first joint portion 13 and vertically above the vertical center of the second joint portion 23. In this case, since the centroids of the first concrete member 10 and the second concrete member 20 can be more reliably lowered, the tension generated at the upper edge of the joint portion P can be more reliably suppressed.

[0067] In this embodiment, the space holding member 70 may be constituted by a foam. In this case, the shape and size of the space holding member 70 can be arbitrary. Therefore, since the handling of the space holding member 70 can be facilitated, the joining operation of the first concrete member 10 and the second concrete member 20 can be performed more efficiently.

[0068] The embodiments of the joining structure and the joining method according to the present disclosure have been described above. However, the joining structure and the joining method according to the present disclosure are not limited to the contents of the above-described embodiments, and may be further modified within the scope of the gist described in the claims. That is, the shape, size, material, number, and arrangement mode of each part of the joining structure according to the present disclosure, and the content and order of the steps of the joining method according to the present disclosure can be appropriately changed within the scope of the above gist.

[0069] FIG. 8 shows a joining structure 90 according to a modified example. As shown in FIG. 8, the joining structure 90 includes a first concrete member 10 having a first end face 11 in which a recess 11b recessed along the juxtaposition direction D4 is formed, and a second end face 21 in which a recess 21b recessed along the juxtaposition direction D4 is formed. It is joined to the second concrete member 20 having The recess 11b and the recess 21b function as shear keys.

[0070] In the joining structure 90, the first concrete member 10 and the second concrete member 20 are arranged such that the recess 11b and the recess 21b face each other along the juxtaposition direction D4. And a space holding member 70 is sandwiched between the recess 11b and the recess 21b. The same operational effects as those of the above-described joining structure 40 can also be obtained from this joining structure 90.

[0071] As shown in FIG. 8, the joining structure 90 has a cavity (space holding member 70) in the filling portion 60, thereby increasing the compressive stress and making the height of the upper filling portion (first filling portion 61) of the filling portion 60 larger than the lower side. Thus, the centroid of the filling portion 60 can be raised. Thereby, even if the amount of protrusion downward of the first protrusion 16 and the second protrusion 26 is reduced, it is possible to prevent the upper surface from being pulled immediately after tensioning. However, in the joining structure 90, the filling portion 60 must be separated vertically, and in order to construct on site, an appropriate inner formwork is required, the accuracy of the placing height management becomes strict, etc., and the construction may be difficult.

[0072] Next, a joining structure 100 according to another modification different from FIG. 8 will be described with reference to FIG. 9. As shown in FIG. 9, the joining structure 100 joins the first concrete member 10 and the second concrete member 20 to each other along the juxtaposition direction D4, which is the direction in which the first end face 11 of the first concrete member 10 and the second end face 21 of the second concrete member 20 are juxtaposed.

[0073] The first concrete member 10 has a first joining portion 13 joined to the second concrete member 20, and the second concrete member 20 has a second joining portion 23 joined to the first concrete member 10. The first joining portion 13 has a first protruding portion 16 protruding vertically downward, and the second joining portion 23 has a second protruding portion 26 protruding vertically downward. The joining structure 100 includes a tension member 52 that penetrates the first protruding portion 16 and the second protruding portion 26 in the juxtaposition direction D4, a filling portion 60 located between the first end face 11 and the second end face 21, and a stress transmission suppression member 101 located between the first end face 11 and the second end face 21 at a position different from the filling portion 60.

[0074] The stress transmission suppression member 101 has, for example, the same function as the above-described space holding member. The stress transmission suppression member 101 suppresses the transmission of stress from the first concrete member 10 and the second concrete member 20. For example, the stress transmission suppression member 101 is provided on each of the first end face 11 and the second end face 21. The stress transmission suppression member 101 is, for example, made of a low-elastic material. The stress transmission suppression member 101 may be made of a low-rigidity material.

[0075] For example, the stress transmission suppressing member 101 is made of expanded polystyrene or sponge. The stress transmission suppressing member 101 may be made of rubber. The stress transmission suppressing member 101 may be a cavity or a bag body having a space inside. In the case of the joining structure 100 having the stress transmission suppressing member 101, the placement of the filling portion 60 can be easily performed. Similar to the case of FIG. 8, the height of the upper filling portion of the filling portion 60 can be made larger than that of the lower side to raise the centroid, and the amount of protrusion downward of the first protrusion 16 and the second protrusion 26 can be reduced. Further, in the joining structure 100, the generation of excessive local stress due to the small filling portion 60 and the decrease in shear transmissibility can be suppressed.

[0076] For example, the filling portion 60 is provided between the stress transmission suppressing member 101 provided on the first end face 11 and the stress transmission suppressing member 101 provided on the second end face 21. The filling portion 60 is filled between a pair of stress transmission suppressing members 101 arranged along the juxtaposition direction D4. Thereby, the filling portion 60 is integrated in the vertical direction (thickness direction D3). As an example, the distance between the first end face 11 and the second end face 21 is 50 mm, and the thickness of the stress transmission suppressing member 101 (length in the juxtaposition direction D4) is 5 mm. The thickness of the stress transmission suppressing member 101 is preferably thinner.

[0077] The joining structure 100 has a plurality of recesses 11b formed in the first end face 11 of the first concrete member 10 and a plurality of recesses 21b formed in the second end face 21 of the second concrete member 20. For example, two recesses 11b are arranged along the thickness direction D3, and two recesses 21b are arranged along the thickness direction D3. Each of the plurality of recesses 11b is arranged along the juxtaposition direction D4 with each of the plurality of recesses 21b. By providing the plurality of recesses 11b and the plurality of recesses 21b as shear keys, sufficient shear transmission can be performed between the first end face 11 and the second end face 21.

[0078] Next, a method for joining the first concrete member 10 and the second concrete member 20 in the joining structure 100 will be described. First, as described above, the first concrete member 10 and the second concrete member 20 are manufactured at a factory. Then, a stress transmission suppressing member 101 is disposed on at least one of the first end face 11 and the second end face 21 (step of disposing the stress transmission suppressing member).

[0079] In the above description, an example in which the stress transmission suppressing members 101 are disposed on both the first end face 11 and the second end face 21 has been described. However, the stress transmission suppressing member 101 may be disposed on only one of the first end face 11 and the second end face 21. FIG. 10 shows an example in which the stress transmission suppressing member 101 is disposed on the first end face 11. For example, the stress transmission suppressing member 101 is attached to at least one of the first end face 11 and the second end face 21 with an adhesive.

[0080] Thereafter, the first end face 11 and the second end face 21 are filled with a fluid packing portion 60 while the both ends and the lower portion in the bridge axis direction D1 between the first end face 11 and the second end face 21 are surrounded by a formwork. For example, the packing portion 60 enters between a pair of stress transmission suppressing members 101 arranged along the juxtaposition direction D4, and the packing portion 60 moves downward, and the packing portion 60 is filled between the first end face 11 and the second end face 21. After the packing portion 60 is cured, a tendon 52 is passed through the sheath pipe 51, and the first concrete member 10 and the second concrete member 20 are tensioned by the tendon 52 penetrating the first protruding portion 16 and the second protruding portion 26 in the juxtaposition direction D4 (tensioning step). Through the above steps, a series of steps of the joining method is completed.

[0081] In the above-described joint structure 100, the space holding member is a stress transmission suppression member 101 that suppresses the transmission of stress from the first concrete member 10 and the second concrete member 20. The stress transmission suppression member 101 may be provided on each of the first end face 11 and the second end face 21. In this case, the transmission of stress from the first concrete member 10 and the second concrete member 20 can be suppressed by the stress transmission suppression member 101. Further, by providing the stress transmission suppression member 101 on each of the first end face 11 and the second end face 21, the filling portion 60 can be passed between the stress transmission suppression member 101 provided on the first end face 11 and the stress transmission suppression member 101 provided on the second end face 21. Therefore, the transmission of stress from the first concrete member 10 and the second concrete member 20 can be suppressed while the filling portion 60 is integrated vertically.

[0082] As in the joint method described above, the stress transmission suppression member 101 may be disposed on at least one of the first end face 11 and the second end face 21. In this case, by disposing the stress transmission suppression member 101 on at least one of the first end face 11 and the second end face 21, the transmission of stress from the first concrete member 10 and the second concrete member 20 can be suppressed. Further, the transmission of stress from the first concrete member 10 and the second concrete member 20 can be suppressed while the filling portion 60 is integrated vertically.

[0083] In the above-described embodiment, an example in which the concrete member 5 and the filling portion 60 are UFCs has been described. However, the concrete member and the filling portion may be made of materials other than UFC.

[0084] In the above-described embodiment, as the step of arranging the space holding member 70, an example in which the space holding member 70 is attached to at least one of the first end face 11 and the second end face 21 has been described. However, in the step of arranging the space holding member 70, after the first end face 11 and the second end face 21 are opposed to each other, the space holding member 70 may be sandwiched (packed) between the first end face 11 and the second end face 21. Thus, the method of arranging the space holding member 70 can be appropriately changed.

[0085] In the above-described embodiment, the joining structure 40 in which the first concrete member 10 and the second concrete member 20 are joined to each other along the crossing direction D2 has been described. However, the direction in which the first concrete member and the second concrete member are joined may be a direction other than the crossing direction D2 (for example, the bridge axis direction D1), and is not particularly limited. In the above-described embodiment, an example in which the tension member 52 is a PC steel bar has been described. However, the tension member 52 may be a wire or the like made of PC steel, and the type of the tension member 52 is not particularly limited.

[0086] In the above-described embodiment, an example in which the sheath pipe 51 and the tension member 52 extend linearly has been described. However, the sheath pipe 51 and the tension member 52 may extend in a curved shape. For example, the sheath pipe 51 and the tension member 52 may extend in an inverted U shape. Thus, the shapes of the sheath pipe 51 and the tension member 52 can be appropriately changed.

[0087] In the above-described embodiment, an example in which the floor slab renewal work of a highway using the UFC floor slab has been described. However, the joining structure and the joining method according to the present disclosure are also applicable to widening of a road bridge or construction of a new floor slab. Further, in the above-described embodiment, the first concrete member 10 and the second concrete member 20 which are floor slabs have been described. However, the first concrete member and the second concrete member may be other than floor slabs, and for example, may constitute a joining structure for joining beams, a joining structure for joining columns, or a joining structure in a box culvert.

Explanation of reference numerals

[0088] 1... Concrete structure, 2... Main girder, 2b... Upper flange, 2c... Web, 2d... Lower flange, 3... Cross girder, 4... Wall railing, 5... Concrete member, 6... Post-tensioning steel, 7... Pretensioning steel, 8... Fixing body, 9... Sheath pipe, 10... First concrete member, 11... First end face, 11b... Recess, 12... Upper surface, 13... First joint, 13b... Lower surface, 13c... Side surface, 14... First extending part, 15... Lower surface, 16... First protruding part, 20... Second concrete member, 21... Second end face, 21b... Recess, 22... Upper surface, 23... Second joint, 23b... Lower surface, 23c... Side surface, 24... Second extending part, 25... Lower surface, 26... Second protruding part, 30... Cross fixing panel, 31... First end face, 32... Upper surface, 33... First joint, 34... First extending part, 35... Protruding part, 35b... Side surface, 35c... Bottom surface, 40... Joint structure, 51... Sheath pipe, 52... Tension member, 53... Fastening part, 60... Filling part, 61... First filling part, 62... Second filling part, 70... Space holding member, 80, 90, 100... Joint structure, 101... Stress transmission suppression member, A... Site, D1... Bridge axis direction, D2... Cross direction, D3... Thickness direction, D4... Parallel arrangement direction, J... Jack, P... Joint part.

Claims

1. A joining structure that joins a first concrete member and a second concrete member to each other along a parallel arrangement direction in which a first end surface of a first concrete member and a second end surface of a second concrete member are aligned, The first concrete member has a first joint portion joined to the second concrete member and a first extension portion extending from the first joint portion in a direction opposite to the second concrete member, The second concrete member has a second joint portion joined to the first concrete member and a second extension portion extending from the second joint portion in a direction opposite to the first concrete member, The first joint portion has a first protruding portion that protrudes vertically downward from a lower surface of the first extension portion, The second joint portion has a second protruding portion that protrudes vertically downward from a lower surface of the second extension portion, A tendon penetrating the first protruding portion and the second protruding portion in the juxtaposition direction; a filler portion located between the first end surface and the second end surface; a space retaining member located between the first end surface and the second end surface and at a location different from the packing portion; Equipped with Joint structure.

2. The spacer portion has a first spacer portion located vertically above the spacer member and a second spacer portion located vertically below the spacer member. The joint structure according to claim 1 .

3. The vertical center of the space holding member is located vertically above the vertical center of the first joint portion and is located vertically above the vertical center of the second joint portion. The joint structure according to claim 1 or 2.

4. The space retaining member is made of a foam. The joint structure according to claim 1 or 2.

5. The space retaining member is a stress transmission suppressing member that suppresses transmission of stress from the first concrete member and the second concrete member, The stress transmission suppression member is provided on each of the first end surface and the second end surface. The joint structure according to claim 1 or 2.

6. A joining method for joining a first concrete member and a second concrete member to each other along a juxtaposition direction in which a first end surface of a first concrete member and a second end surface of a second concrete member are aligned, comprising: The first concrete member has a first joint portion joined to the second concrete member and a first extension portion extending from the first joint portion in a direction opposite to the second concrete member, The second concrete member has a second joint portion joined to the first concrete member and a second extension portion extending from the second joint portion in a direction opposite to the first concrete member, The first joint portion has a first protruding portion that protrudes vertically downward from a lower surface of the first extension portion, The second joint portion has a second protruding portion that protrudes vertically downward from a lower surface of the second extension portion, disposing a space retaining member on at least one of the first end surface and the second end surface; placing the first end surface and the second end surface opposite each other; filling a space between the first end surface and the second end surface with a spacer portion and hardening the spacer portion; tensioning the first concrete member and the second concrete member with a tendon passing through the first protruding portion and the second protruding portion in the juxtaposition direction; Equipped with Joining method.

7. The space retaining member is a stress transmission suppressing member that suppresses transmission of stress from the first concrete member and the second concrete member, In the step of arranging the space retaining member, the stress transmission suppressing member is arranged on at least one of the first end surface and the second end surface. The joining method according to claim 6.

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