Joining method and deck structure

Abstract

To provide precast concrete floor slabs supported in two directions, one in the direction of a bridge axis and the other in the direction perpendicular to the bridge axis, a joining method for smoothly introducing pre-stress into a joint in the direction of the bridge axis and a floor slab structure, and a joining method and a floor slab structure that can reduce the number of intervening members between a pair of precast concrete floor slabs.SOLUTION: A joining method according to one embodiment comprises the steps of: placing each precast concrete floor slab 5 at a position spaced apart from a support member 3 above each of a plurality of support members 3 extending in the direction perpendicular to the bridge axis, and placing a plurality of precast concrete floor slabs 5 facing each other at a position other than directly above the support members 3; forming a joint 7 by filling a filler material 30 between a pair of precast concrete floor slabs 5 facing each other in a bridge axis direction D1; introducing pre-stress into a plurality of consecutive precast concrete floor slabs 5 in the bridge axial direction D1 by means of tensioning material 20; and filling the slabs with an inter-filling material 40.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a deck slab joining method and a deck slab structure. [Background technology]

[0002] JP 2019-127770 A describes a joint structure for precast concrete slabs. In this joint structure, the precast concrete slabs have joint end faces, and the joint end faces of two precast concrete slabs are arranged so as to face each other. A plurality of loop-shaped reinforcing members protrude from both joint end faces.

[0003] A plurality of lateral reinforcing members are then arranged in a direction substantially perpendicular to the protruding direction of the reinforcing members, and joint concrete is poured to embed the reinforcing members and the lateral reinforcing members. In this joint structure, a plurality of loop-shaped reinforcing members and a plurality of lateral reinforcing members are interposed between a pair of precast concrete slabs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-127770 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when a support member for supporting a precast concrete slab is provided and a pair of precast concrete slabs face each other on the support member, an intervening member may be required to support the pair of precast concrete slabs and to be inserted between the pair of precast concrete slabs. However, in order to improve workability, it may be required to omit the intervening member. Therefore, it may be required to reduce the number of members intervening between the pair of precast concrete slabs.

[0006] An object of the present disclosure is to provide a joining method and a deck structure that can reduce the number of members interposed between a pair of precast concrete decks. [Means for solving the problem]

[0007] The joining method according to the present disclosure is a joining method for joining multiple precast concrete slabs along the bridge axis direction, the bridge axis transverse direction perpendicular to the bridge axis direction, and the height direction perpendicular to both the bridge axis direction and the bridge axis transverse direction. The joining method includes the steps of: installing each precast concrete slab at a position spaced apart from each of the multiple support members extending in the bridge axis transverse direction, and facing the multiple precast concrete slabs to each other at a position other than directly above the support members; filling a filler material between a pair of precast concrete slabs facing each other along the bridge axis direction to form a joint; introducing prestress into the multiple precast concrete slabs that are continuous in the bridge axis direction by means of a tension member; and filling a filler material between the precast concrete slabs and the support members.

[0008] In this joining method, multiple precast concrete slabs are joined along the bridge axis direction. A precast concrete slab is installed at a position spaced apart from each of the multiple support members extending in the direction perpendicular to the bridge axis. A pair of precast concrete slabs face each other at a position other than directly above the support members, and prestress is introduced in the bridge axis direction to the multiple precast concrete slabs with a filler filled between the pair of precast concrete slabs. Therefore, prestress can be introduced in the bridge axis direction without restraining the displacement of the precast concrete slab relative to the support members. In addition, since the pair of precast concrete slabs face each other at a position other than directly above the support members, an intervening member that slides when prestress is introduced in the bridge axis direction can be eliminated. Therefore, the number of intervening members between the pair of precast concrete slabs can be reduced.

[0009] The above-mentioned joining method may include a step of introducing prestress into the joint in a direction perpendicular to the bridge axis after the step of forming the joint. In this case, prestress can be introduced into the joint of a pair of precast concrete decks in the direction perpendicular to the bridge axis.

[0010] The deck structure according to the present disclosure includes a plurality of support members extending in a bridge axis transverse direction perpendicular to the bridge axis direction, a plurality of precast concrete decks extending in the bridge axis direction, the bridge axis transverse direction, and a height direction perpendicular to both the bridge axis direction and the bridge axis transverse direction and arranged along the bridge axis direction while being installed at a position spaced apart from each of the plurality of support members above, a filler filled between a pair of precast concrete decks arranged along the bridge axis direction, a tension member inserted into the plurality of precast concrete decks along the bridge axis direction, and a filler filled between the precast concrete decks and the support members. Prestress is introduced into the plurality of precast concrete decks that are continuous in the bridge axis direction by the tension member, and the plurality of precast concrete decks face each other at positions other than directly above the support members.

[0011] In this deck structure, a precast concrete deck is installed at a position spaced apart from each of the support members above each of the support members extending perpendicular to the bridge axis. The pair of precast concrete decks face each other at a position other than directly above the support members, and prestress in the bridge axis direction is introduced to the precast concrete decks by the tension members with filler material filled between the pair of precast concrete decks. Thus, prestress in the bridge axis direction can be introduced to the precast concrete decks without restraining the displacement of the precast concrete decks relative to the support members. In addition, since the pair of precast concrete decks face each other at a position other than directly above the support members, it is possible to eliminate the need for an intervening member that slides when prestress is introduced in the bridge axis direction. Therefore, the number of intervening members between the pair of precast concrete decks can be reduced. Effect of the Invention

[0012] According to the present disclosure, the number of components interposed between a pair of precast concrete decks can be reduced. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a plan view showing the deck structure according to the embodiment. [Diagram 2] FIG. 2 is a bottom view showing an example of a precast concrete floor slab according to an embodiment. [Diagram 3] FIG. 2 is a vertical cross-sectional view showing the joint structure of FIG. [Figure 4] FIG. 11 is a plan view showing a joint structure according to a reference example. [Diagram 5] FIG. 4 is a vertical cross-sectional view showing a joint structure according to a reference example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a deck joining method and deck structure 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 given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those shown in the drawings.

[0015] FIG. 1 is a plan view showing a bridge B having a site A to which a deck structure 1 and a joining method according to this embodiment are applied. As shown in FIG. 1, the bridge B includes a plurality of girders 2 extending in a bridge axis direction D1, a plurality of support members 3 extending in a direction perpendicular to the bridge axis D2 between the plurality of girders 2, and a plurality of precast concrete decks 5 arranged on the plurality of girders 2 so as to extend in the direction perpendicular to the bridge axis D2. The girders 2 and the support members 3 are arranged below the precast concrete decks 5. As an example, the site A is a construction site on an expressway. For example, at the site A, construction work for constructing a new bridge using the precast concrete decks 5 is carried out.

[0016] The multiple girders 2 include, for example, multiple steel main girders 2A and multiple side vertical girders 2B. The steel main girders 2A are thicker than the side vertical girders 2B. The steel main girders 2A are provided between a pair of side vertical girders 2B arranged in the bridge axis perpendicular direction D2. As an example, two steel main girders 2A and two side vertical girders 2B are provided, and the two steel main girders 2A are arranged between the two side vertical girders 2B. In the following description, when it is not necessary to distinguish between the steel main girders 2A and the side vertical girders 2B, the steel main girders 2A and the side vertical girders 2B will be collectively described as girder 2. The girder 2 is, for example, a steel girder having an upper flange, a web, and a lower flange. However, the girder 2 is not limited to a steel girder, and may be, for example, a PC girder.

[0017] The precast concrete slab 5 is a rectangular slab with short sides extending in the bridge axis direction D1 and long sides extending in the direction perpendicular to the bridge axis D2, and a thickness in the height direction D3 (see FIG. 3). The height direction D3 is perpendicular to both the bridge axis direction D1 and the direction perpendicular to the bridge axis D2. The precast concrete slab 5 is, for example, a UFC slab made of ultra high strength fiber reinforced concrete (UFC). In this case, at the site A, construction work for building a new expressway bridge using UFC slabs is being carried out.

[0018] Fig. 2 is a bottom view of the precast concrete slab 5 as viewed from below. As shown in Fig. 2, for example, lattice-like ribs 5c are formed on the lower surface 5b of the precast concrete slab 5. The lattice-like ribs 5c include a plurality of bridge axis direction ribs 5d extending in the bridge axis direction D1 and a plurality of bridge axis perpendicular direction ribs 5f extending in the bridge axis perpendicular direction D2. The precast concrete slab 5 with the lattice-like ribs 5c formed on the lower surface 5b is sometimes called a waffle-type slab.

[0019] Fig. 3 is an enlarged longitudinal sectional view of a pair of precast concrete slabs 5 in the slab structure 1 according to this embodiment. As shown in Fig. 3, the precast concrete slab 5 has, for example, a plurality of PC steel members 6 extending in the direction perpendicular to the bridge axis D2, and prestress is introduced in the direction perpendicular to the bridge axis D2. For example, the precast concrete slab 5 has prestress introduced only in the direction perpendicular to the bridge axis D2 by a pretensioning method.

[0020] The deck structure 1 comprises a support member 3, and tendons 20 that introduce prestress by a post-tensioning method to multiple precast concrete decks 5 lined up in the bridge axis direction D1. The deck structure 1 further comprises a filler 30 that is filled between a pair of precast concrete decks 5 to form a joint 7, and a filler 40 that is filled between the support member 3 and the precast concrete deck 5. In this embodiment, the filler 30 forms a horizontal joint of the deck structure 1.

[0021] The support member 3 is, for example, a steel horizontal rib extending in the direction D2 perpendicular to the bridge axis. The support member 3 has an upper flange 3b, a web 3c, and a lower flange 3d. The precast concrete floor slab 5 has an end face 5h that faces the other precast concrete floor slabs 5 in the bridge axis direction D1. For example, the end face 5h is flat and extends in the direction D2 perpendicular to the bridge axis and in the height direction D3.

[0022] The filler 30 is filled between the pair of end faces 5h. For example, the filler 30 is a cement-based material that has fluidity when filled and hardens after a certain time has passed since filling. The filler 30 may be non-shrink mortar or cast-in-place UFC or UHPFRC (Ultra High Performance Fiber Reinforced Cementitious Composite), and various materials can be used as the filler 30.

[0023] The joint 7 is formed by filling the gap between a pair of end faces 5h with a filler 30. In the joint 7, a pair of precast concrete floor slabs 5 face each other at a position other than directly above the support members 3. In other words, the multiple precast concrete floor slabs 5 face each other at a position other than directly above the support members 3 that is spaced apart from the support members 3. In this embodiment, "a position other than directly above" refers to a position other than vertically above, and indicates, for example, a state in which the positions are misaligned in a plan view.

[0024] In the deck structure 1, a pair of precast concrete decks 5 and the filler 30 are integrated by prestress. The tendons 20 are inserted through a plurality of bridge axis-perpendicular ribs 5f. The tendons 20 may be inserted so as to cross the plurality of bridge axis-perpendicular ribs 5f, or may be inserted through the bridge axis-direction ribs 5d. That is, an external cable system in which the tendons 20 are exposed between the plurality of bridge axis-perpendicular ribs 5f may be adopted, or an internal cable system in which the tendons 20 are arranged within the bridge axis-direction ribs 5d may be adopted. For example, a sheath extending in the bridge axis direction D1 is embedded in each bridge axis-perpendicular rib 5f, and the tendons 20 are inserted into the sheaths of the plurality of bridge axis-perpendicular ribs 5f. In this way, the tendons 20 are inserted through a plurality of precast concrete decks 5 arranged in the bridge axis direction D1, and are fixed by anchoring parts (not shown) located outside the bridge axis direction D1 of the plurality of precast concrete decks 5.

[0025] The deck structure 1 has a shear stopper member 50 that allows displacement of the multiple precast concrete decks 5 relative to the support member 3 when prestress is being introduced to the multiple precast concrete decks 5 by the tendons 20. The shear stopper member 50 includes a first shear stopper member 51 that protrudes downward from the precast concrete deck 5 and a second shear stopper member 52 that protrudes upward from the support member 3. For example, the first shear stopper member 51 protrudes downward from a rib 5f perpendicular to the bridge axis of the precast concrete deck 5, and the second shear stopper member 52 protrudes upward from an upper flange 3b of the support member 3.

[0026] The length of the first shear stopper member 51 (length in the height direction D3) and the length of the second shear stopper member 52 are each shorter than the height of the filler material 40 filled in the space S between the precast concrete floor slab 5 and the support member 3. As shown in Figs. 1 and 3, the space S is formed by a space retaining member 8 placed on a floor structure formed by multiple girders 2 and multiple support members 3. As an example, the space retaining member 8 is a height adjustment bolt that protrudes downward from the lower surface 5b of the precast concrete floor slab 5. However, the space retaining member 8 may be something other than a height adjustment bolt, and the type of the space retaining member 8 is not particularly limited.

[0027] A plurality of space retaining members 8 are placed on the floor structure, and a space S is formed by interposing the space retaining members 8 between the floor structure and the precast concrete floor slab 5. The space filler 40 filled in the space S is, for example, a cement-based material that has fluidity when filled and hardens after a certain time has passed since filling. The material of the space filler 40 may be the same as the material of the filler 30.

[0028] The shear stopper member 50 includes, for example, a plurality of first shear stopper members 51 and a plurality of second shear stopper members 52, and the first shear stopper members 51 and the second shear stopper members 52 are alternately arranged in the bridge axis direction D1. For example, the first shear stopper member 51 is a bolt (an insert bolt is one example), and the second shear stopper member 52 is a headed stud (stud dowel). However, the type of the first shear stopper member 51 and the type of the second shear stopper member 52 are not limited to the above-mentioned bolt or headed stud, and are not particularly limited.

[0029] Next, a joining method for the precast concrete slab 5 according to this embodiment will be described. First, the precast concrete slab 5 is prepared. At this time, as an example, prestress may be introduced to the precast concrete slab 5 only in the direction perpendicular to the bridge axis D2 by a pretensioning method at a manufacturing plant for the precast concrete slab 5.

[0030] In this case, tension is applied to the PC steel members 6 arranged in the direction D2 perpendicular to the bridge axis before the concrete that makes up the precast concrete deck 5 is poured, and the tension is released after the concrete is poured and hardened. In this way, multiple precast concrete decks 5 are prepared in which prestress is introduced only in the direction D2 perpendicular to the bridge axis (a process of introducing prestress in the direction perpendicular to the bridge axis using the pretensioning method).

[0031] Then, a space retaining member 8 is placed on the floor structure formed by the multiple girders 2 and multiple support members 3, and multiple precast concrete floor slabs 5 are installed on the floor structure. If the space retaining member 8 is a height adjustment bolt, the precast concrete floor slab 5 is installed on the floor structure with the space retaining member 8 protruding from the underside 5b of the precast concrete floor slab 5. At this time, the multiple precast concrete floor slabs 5 are installed so as to be lined up in the bridge axis direction D1 above the floor structure.

[0032] That is, each precast concrete slab 5 is installed at a position spaced apart from each of the multiple support members 3 extending in the direction perpendicular to the bridge axis D2. Then, the multiple precast concrete slabs 5 are made to face each other at a position other than directly above the support members 3 (the process of making the multiple precast concrete slabs face each other).

[0033] Also, the tendons 20 are inserted through the multiple precast concrete decks 5. At this time, the tendons 20 are inserted along the bridge axis direction D1 into the sheaths of the bridge axis perpendicular ribs 5f of the multiple precast concrete decks 5 that are continuous in the bridge axis direction D1 (step of inserting the tendons). At this time, as described above, the tendons 20 may be inserted so as to cross the multiple bridge axis perpendicular ribs 5f (external cable method), or the tendons 20 may be inserted into the sheaths provided within the bridge axis direction ribs 5d (internal cable method).

[0034] Filler 30 is filled between a pair of precast concrete decks 5 arranged in the bridge axis direction D1. The aforementioned insertion of the tension member 20 may be performed after filling the filler 30. Then, the filler 30 is hardened to form a joint 7 between the pair of precast concrete decks 5 (step of forming a joint). After forming the joint 7, prestress may be introduced to the joint 7 in the direction perpendicular to the bridge axis D2 (step of introducing prestress in the direction perpendicular to the bridge axis). Specifically, PC steel may be placed in the horizontal joint formed by the filler 30 or in the vicinity of the horizontal joint, and prestress may be introduced by a post-tensioning method in the direction perpendicular to the bridge axis D2 after the filler 30 has hardened.

[0035] Then, prestress is introduced by the post-tensioning method to the multiple precast concrete slabs 5 that are continuous in the bridge axial direction D1 using the tendons 20. Specifically, one end of the tendons 20 is fixed to the above-mentioned anchorage, and a reaction force is obtained from the precast concrete slab 5 to pull the other end of the tendons 20, thereby applying a compressive force in the bridge axial direction D1 to the multiple precast concrete slabs 5 (a process of introducing prestress by tendons). In other words, prestress is introduced by obtaining a reaction force from the precast concrete slab 5 that pulls the tendons 20.

[0036] When prestress is introduced by the tendons 20, the multiple precast concrete floor slabs 5 are capable of displacement relative to the support members 3. In other words, the multiple precast concrete floor slabs 5 and the filler 30 are capable of sliding relative to the support members 3. Therefore, prestress can be smoothly introduced to the multiple precast concrete floor slabs 5 as the tendons 20 are tensioned.

[0037] As described above, after the prestress is introduced, the other end of the tendon 20 is fixed to the anchorage. Then, filler 40 is filled between the precast concrete slab 5 and the support member 3 (step of filling with filler). The filler 40 is hardened to integrate the support member 3 with the filler 40, and the filler 40 with the precast concrete slab 5, and then the series of steps is completed. More specifically, the series of steps is completed after the step of grouting the gap between the tendon 20 and the sheath after tensioning.

[0038] Next, the effects of the joining method of the precast concrete slabs 5 and the slab structure 1 according to this embodiment will be described. In the joining method and the slab structure 1 according to this embodiment, multiple precast concrete slabs 5 are joined along the bridge axis direction D1. The precast concrete slabs 5 are installed at positions spaced apart from the support members 3 above each of the multiple support members 3 extending in the direction perpendicular to the bridge axis D2. A pair of precast concrete slabs 5 face each other at positions other than directly above the support members 3, and prestress is introduced to the multiple precast concrete slabs 5 in the bridge axis direction D1 with a filler 30 filled between the pair of precast concrete slabs 5. Therefore, prestress can be introduced in the bridge axis direction D1 without restraining the displacement of the precast concrete slabs 5 relative to the support members 3.

[0039] In addition, since the pair of precast concrete slabs 5 face each other at a position other than directly above the support member 3, an intervening member that slides when prestress is introduced in the bridge axis direction D1 can be eliminated. Specifically, as shown in the reference example of Fig. 4 and Fig. 5, when the pair of precast concrete slabs 5 face each other directly above the support member 3 and the joint 7 is provided vertically above the support member 3, an intervening member 10 that can slide in the bridge axis direction D1 relative to the support member 3 and a fastening member 70 may be required. By making the multiple precast concrete slabs 5, the filler 30, and the intervening member 10 slidable relative to the support member 3 in a state where the intervening member 10 is not firmly fastened by the fastening member 70, the intervening member 10 slides with tension by the tension member 20. By providing this intervening member 10, prestress can be introduced smoothly.

[0040] However, in the deck structure 1 and joining method according to this embodiment, a pair of precast concrete decks 5 face each other at a position other than directly above the support members 3, so that prestress can be smoothly introduced to multiple precast concrete decks 5 without the intervening members 10. In other words, prestress can be introduced in the bridge axis direction D1 without restraining the displacement of the precast concrete deck 5 relative to the support members 3. Therefore, the number of members interposed between a pair of precast concrete decks 5 can be reduced.

[0041] As described above, the joining method according to this embodiment may include a step of introducing prestress in the direction perpendicular to the bridge axis D2 to the joint 7 (for example, at a horizontal joint or in the vicinity of the horizontal joint) after the step of forming the joint 7. In this case, prestress can be introduced in the direction perpendicular to the bridge axis D2 to the joint 7 of a pair of precast concrete floor slabs 5.

[0042] The above describes the embodiments of the joining method and deck structure according to the present disclosure. However, the joining method and deck structure according to the present disclosure are not limited to the above-mentioned embodiments, and can be modified as appropriate within the scope of the gist described in the claims. In other words, the structure, shape, size, material, number and arrangement of each part of the deck structure, as well as the content and order of the steps of the joining method, can be modified as appropriate within the scope of the above gist.

[0043] For example, in the above embodiment, an example has been described in which prestress is introduced in the direction perpendicular to the bridge axis D2 by a pretensioning method in a manufacturing factory for the precast concrete deck 5. However, prestress may be introduced by a post-tensioning method in a location other than the manufacturing factory for the precast concrete deck 5 (for example, the site A).

[0044] In the above embodiment, an example has been described in which the end face 5h of the precast concrete floor slab 5 facing the other precast concrete floor slab 5 in the bridge axis direction D1 is flat. However, the end face 5h of the precast concrete floor slab 5 facing the other precast concrete floor slab 5 in the bridge axis direction D1 may be formed with projections and recesses. In this case, the pair of precast concrete floor slabs 5 can be more firmly integrated.

[0045] In the above embodiment, the precast concrete floor slab 5 is a waffle-type floor slab having the lattice ribs 5c formed on the lower surface 5b. However, the precast concrete floor slab may be a precast concrete floor slab without the lattice ribs 5c, and the type of the precast concrete floor slab can be changed as appropriate. [Explanation of symbols]

[0046] 1...deck slab structure, 2...girder, 2A...steel main girder, 2B...side vertical girder, 3...support member, 3b...upper flange, 3c...web, 3d...lower flange, 5...precast concrete deck, 5b...underside, 5c...lattice rib, 5d...rib in bridge axis direction, 5f...rib perpendicular to bridge axis, 5h...end face, 6...PC steel, 7...joint, 8...space retaining member, 10...intervening member, 20...tension member, 30...filling material, 40...filling material, 50...slip prevention member, 51...first slip prevention member, 52...second slip prevention member, 70...fastening member, A...site, B...bridge, D1...bridge axis direction, D2...perpendicular to bridge axis, D3...height direction D3, S...space.

Claims

1. A joining method for joining a plurality of precast concrete floor slabs extending in a bridge axis direction, a bridge axis perpendicular direction perpendicular to the bridge axis direction, and a height direction perpendicular to both the bridge axis direction and the bridge axis perpendicular direction along the bridge axis direction, A process of installing each of the precast concrete slabs at a position above and spaced from a plurality of support members extending in a direction perpendicular to the bridge axis, so that the plurality of precast concrete slabs face each other at positions other than directly above the support members; A step of filling a filler between a pair of the precast concrete slabs facing each other along the bridge axis to form a joint; A step of introducing prestress into a plurality of the precast concrete decks that are continuous in the bridge axis direction by using tendons; A step of filling a gap between the precast concrete slab and the support member; A joining method comprising:

2. After the step of forming the joint, a step of introducing prestress into the joint in a direction perpendicular to the bridge axis is provided. The joining method according to claim 1 .

3. A plurality of support members extending in a direction perpendicular to the bridge axis direction, the support members being A plurality of precast concrete floor slabs extending in the bridge axis direction, the direction perpendicular to the bridge axis, and a height direction perpendicular to both the bridge axis direction and the bridge axis direction, and arranged along the bridge axis direction while being installed at a position spaced apart from each of the plurality of support members above the respective support members; A filler material is filled between a pair of the precast concrete slabs arranged along the bridge axis direction; Tendons inserted through the plurality of precast concrete decks along the bridge axis; A filler material is filled between the precast concrete slab and the support member; Equipped with Prestress is introduced into the plurality of precast concrete slabs that are continuous in the bridge axis direction by the tension members, The plurality of precast concrete floor slabs face each other at positions other than directly above the support members. Floor slab structure.

Images