Floor-slab joint structure of precast floor slab and floor-slab joint method

Abstract

To provide a technique related to a joint structure of a precast floor slab excellent in bearing force of a joint part.SOLUTION: The floor slab joint structure includes a first upper joint reinforcement and a first lower joint reinforcement that protrude from a first joint end surface of the first precast floor slab and have anchoring bodies formed on tip sides thereof, a second upper joint reinforcement and a second lower joint reinforcement that protrude from a second joint end surface of the second precast floor slab and have anchoring bodies formed on tip sides thereof, an upper reinforcing bar that is arranged along the first upper joint reinforcement and the second upper joint reinforcement in a joint orthogonal direction, and a lower reinforcing bar that is arranged along the first lower joint reinforcement and the second lower joint reinforcement in the joint orthogonal direction, the first upper-stage joint reinforcement and the second upper-stage joint reinforcement are joined to each other and the first lower-stage joint reinforcement and the second lower-stage joint reinforcement are joined to each other by empty lap joints, respectively.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a deck joint structure and a deck joint method for precast decks. [Background technology]

[0002] Conventionally, concrete precast decks have been widely used in new bridge deck construction and replacement work, and various deck joint structures are known. In this type of deck joint structure, a pair of precast decks to be connected are installed at a predetermined distance in the joint direction (connecting direction) so that a joint space is formed between them. Joint reinforcing bars protrude from the joint end faces of each precast deck facing each other across the joint space, and in this state, the precast decks are connected together via filler concrete, filler mortar, or the like (hereinafter referred to as "filling material") filled (cast) into the joint space.

[0003] In this regard, a deck slab joint structure is known in which reinforcing bars protruding from the end faces of deck slabs installed at a predetermined interval are joined by open lap joints (see, for example, Patent Document 1). In the deck slab joint structure described in Patent Document 1, anchors are formed at the tips of the reinforcing bars protruding from the end faces of the deck slabs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-55531 Summary of the Invention [Problem to be solved by the invention]

[0005] A deck joint structure that uses an open lap joint method between reinforcing bars with anchors formed at the ends, as described in Patent Document 1, is said to make it possible to reduce labor during construction and also shorten the construction period.

[0006] While labor savings during construction are certainly an advantage, a basic requirement for deck joint structures is that the joints (anchorages) must have sufficient strength. The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide technology related to precast deck joint structures with excellent strength at the joints. [Means for solving the problem]

[0007] The technology disclosed herein is a slab joint structure in which a filler material is filled into a joint space formed by installing the joint end surfaces of a first precast concrete slab and a second precast concrete slab at an interval, a first upper joint reinforcing bar and a first lower joint reinforcing bar that protrude from the first joint end surface of the first precast floor slab toward the joint space and have anchors formed at their tip ends, and are arranged in a direction perpendicular to the joint; second upper joint reinforcing bars and second lower joint reinforcing bars that protrude from the second joint end surface of the second precast floor slab toward the joint space and have anchors formed on their tip sides, and are arranged in multiple rows in a direction perpendicular to the joint; In the joint space, an upper reinforcing bar is arranged along the first upper joint reinforcing bar and the second upper joint reinforcing bar in a direction perpendicular to the joint; In the joint space, a lower reinforcing bar is arranged along the first lower joint reinforcing bar and the second lower joint reinforcing bar in a direction perpendicular to the joint; Equipped with The first upper joint reinforcing bar and the second upper joint reinforcing bar, and the first lower joint reinforcing bar and the second lower joint reinforcing bar are respectively joined by an open lap joint.

[0008] Here, the upper reinforcing bars may be arranged above the first upper joint reinforcing bars and the second upper joint reinforcing bars, and the lower reinforcing bars may be arranged below the first lower joint reinforcing bars and the second lower joint reinforcing bars.

[0009] In addition, the deck joint structure may be such that, when viewed in a plan view, the first upper joint reinforcing bar and the second upper joint reinforcing bar are arranged alternately in a direction perpendicular to the joint, and the first lower joint reinforcing bar and the second lower joint reinforcing bar are arranged alternately in a direction perpendicular to the joint.

[0010] In addition, the deck joint structure may be such that the first upper joint reinforcing bar and the first lower joint reinforcing bar are arranged side by side, one above the other, and the second upper joint reinforcing bar and the second lower joint reinforcing bar are arranged side by side, one above the other.

[0011] In addition, the deck joint structure may be such that the first upper joint reinforcing bar and the second upper joint reinforcing bar are arranged at the same height, and the first lower joint reinforcing bar and the second lower joint reinforcing bar are arranged at the same height.

[0012] Furthermore, the first upper joint reinforcing bar, the second upper joint reinforcing bar, the first lower joint reinforcing bar, and the second lower joint reinforcing bar are When a tensile force acts on these, the average cross-sectional area of ​​the compression strut region where compression struts are formed between the anchors provided on the first upper joint reinforcing bar and the second upper joint reinforcing bar adjacent to each other in the direction perpendicular to the joint, and between the anchors provided on the first lower joint reinforcing bar and the second lower joint reinforcing bar adjacent to each other in the direction perpendicular to the joint, divided by the joint reinforcing bar lap length, is 560 mm 3 / mm or more.

[0013] The technology according to the present disclosure may be a slab joint method for connecting a first precast slab and a second precast slab made of concrete. That is, the deck slab joint method according to the present disclosure is as follows: a first floor slab installation process for installing a first precast floor slab in a predetermined position, in which a plurality of first upper joint reinforcing bars and a plurality of first lower joint reinforcing bars, each of which protrudes from the first joint end surface and has an anchor formed at its tip side, are arranged in a direction perpendicular to the joint; a second floor slab installation process in which a second precast floor slab is installed at a distance from the first precast floor slab, the second precast floor slab having a plurality of second upper joint reinforcing bars and second lower joint reinforcing bars each arranged in a direction perpendicular to the joint, the second upper joint reinforcing bars having anchors formed on the tip side and protruding from the second joint end surface, so that a joint space is formed between the first joint end surface and the second joint end surface; a step of filling the joint space with filler material in a state in which the upper reinforcing bars are arranged so as to be along the first upper joint reinforcing bars and the second upper joint reinforcing bars, and the lower reinforcing bars are arranged so as to be along the first lower joint reinforcing bars and the second lower joint reinforcing bars, along the joint orthogonal direction in the joint space; Equipped with The first upper joint reinforcing bar and the second upper joint reinforcing bar, and the first lower joint reinforcing bar and the second lower joint reinforcing bar are respectively joined by an open lap joint.

[0014] In addition, the deck slab joint method according to the present disclosure includes: A lower reinforcing bar arrangement process in which lower reinforcing bars are arranged in advance along a direction perpendicular to the joints so as to be along the lower sides of the plurality of first lower joint reinforcing bars, prior to at least the second floor slab installation process; After the second floor slab installation process, an upper reinforcing bar arrangement process is performed in which upper reinforcing bars are arranged along the upper sides of the first upper joint reinforcing bars and the second upper joint reinforcing bars in a direction perpendicular to the joints; Further provided with In the second slab installing step, the second precast slab may be installed so that the lower reinforcing bars are located below the plurality of second lower joint reinforcing bars.

[0015] Here, the lower reinforcing bars may be arranged in advance in the first lower joint reinforcing bars before the first precast floor slab is installed in a predetermined position.

[0016] Further, the first upper joint reinforcing bar and the first lower joint reinforcing bar are arranged vertically side by side, and the second upper joint reinforcing bar and the second lower joint reinforcing bar are arranged vertically side by side, In the second deck installation process, the second precast deck may be installed so that the second lower joint reinforcing bars are inserted from above into the gaps between the first upper joint reinforcing bars adjacent to each other in the direction perpendicular to the joints.

[0017] Furthermore, at the completion of the second deck installation process, the second upper joint reinforcing bar may be positioned at the same height as the first upper joint reinforcing bar, and the second lower joint reinforcing bar may be positioned at the same height as the first lower joint reinforcing bar. [Effects of the Invention]

[0018] According to the present invention, a technology can be provided for a joint structure of a precast deck having excellent bearing strength at the joint portion. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a plan view showing a deck slab joint structure 1. As shown in FIG. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 3 is a front view taken along the arrow B in FIG. [Figure 4] FIG. 4 is a diagram showing the first precast floor slab and the second precast floor slab connected together. [Figure 5] FIG. 5 is a diagram illustrating the construction procedure for the deck joint structure. [Figure 6] FIG. 6 is a diagram illustrating the state of the preparation process. [Figure 7] FIG. 7 is a diagram illustrating the construction status of the deck slab joint structure. [Figure 8] FIG. 8 is a diagram illustrating the construction status of the deck slab joint structure. [Figure 9] FIG. 9 is a diagram illustrating the construction procedure for the deck slab joint structure. [Figure 10] FIG. 10 is a diagram showing a schematic diagram of a compression strut region formed by the action of an anchor when a tensile force acts on a joint reinforcing bar. [Figure 11] FIG. 11 is a diagram illustrating a load test device used in the fixation test. [Figure 12] FIG. 12 is a diagram illustrating a test specimen used in a fixing test. [Figure 13] Figure 13 shows the materials used to fabricate the test specimens. [Figure 14] Figure 14 shows the specifications of each case in the test specimen. [Figure 15] Figure 15 shows the composition of the fiber-reinforced filler used to fabricate the test specimens. [Figure 16] Figure 16 shows the loading age of each specimen and the compressive strength test results of the fiber-reinforced filler at each age. [Figure 17] FIG. 17 shows a list of the results of the fixation test. [Figure 18] FIG. 18 is a diagram illustrating a deck slab joint structure according to a modified example. [Figure 19] FIG. 19 is a diagram illustrating a deck slab joint structure according to another modified example. [Figure 20] FIG. 20 is a diagram illustrating a construction procedure corresponding to the modified example. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] <Embodiment> In the embodiments, a slab joint structure and a slab joint method for connecting concrete precast slabs will be described. Here, as an example, a slab joint structure 1 and a method thereof will be described for connecting (joining) multiple precast slabs 2 laid continuously in the bridge axis direction in new construction or renewal construction of slabs in a bridge. Note that in this specification, "made of concrete" means that it is composed of at least concrete, and reinforced concrete also falls into the category of made of concrete.

[0022] FIG. 1 is a plan view showing the deck slab joint structure 1. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1. FIG. 3 is a front view taken along the line B in FIG. 1. Reference numerals 2A and 2B denote a pair of precast decks made of reinforced concrete to be connected using the deck slab joint structure 1, and for convenience, they are referred to as the "first precast deck 2A" and the "second precast deck 2B." When there is no need to distinguish between them, they may simply be referred to as the "precast deck 2." Note that, for convenience, in FIG. 1, the reinforcing bars and the like embedded in the precast deck slab 2 are shown visible through the concrete that defines the outer shape of the precast deck slab 2.

[0023] In Figures 1 to 3, the X direction indicates the "bridge axis direction" in which the bridge extends. The X direction (bridge axis direction) also coincides with the "joint direction" connecting the precast deck slabs 2 and the length direction of the precast deck slab 2. The Y direction indicates the direction perpendicular to the bridge axis. The Y direction (direction perpendicular to the bridge axis) also coincides with the joint perpendicular direction that is perpendicular to the joint direction between the precast deck slabs 2 and the deck width direction of the precast deck slab 2. The Z direction indicates the up-down direction (height direction) and coincides with the thickness direction of the precast deck slab 2.

[0024] In the deck joint structure 1, the joint end faces 21A, 21B of the first precast deck 2A and the second precast deck 2B are spaced apart in the joint direction (X direction) to form a joint space (void) S1, which is then filled (cast) with filler material, thereby connecting (joining) the first precast deck 2A and the second precast deck 2B together in the joint direction. Here, an example will be described in which a fiber-reinforced filler material is used as the filler material.

[0025] The deck joint structure 1 is composed of a first upper joint reinforcing bar 22A and a first lower joint reinforcing bar 23A that protrude from the first joint end face 21A of the first precast deck 2A toward the joint space S1, a second upper joint reinforcing bar 22B and a second lower joint reinforcing bar 23B that protrude from the second joint end face 21B of the second precast deck 2B toward the joint space S1, and upper reinforcing bars 27A and lower reinforcing bars 27B that are arranged in the joint space S1.

[0026] As shown in Figures 1 and 2, inside the first precast deck 2A and the second precast deck 2B, deck main reinforcements (vertical reinforcements) 24 are arranged along the bridge axis direction (X direction), and deck distribution reinforcements (horizontal reinforcements) 25 are arranged to intersect with the deck main reinforcements 24 in the direction perpendicular to the bridge axis (Y direction). The deck main reinforcements 24 and deck distribution reinforcements 25 are arranged in two tiers, one above the other. The reinforcing bars used for the deck main reinforcements 24 and deck distribution reinforcements 25, their spacing, and direction of reinforcement are not particularly limited. For example, deformed reinforcing bars of SD345 and D19 (designation) are used for the deck main reinforcements 24, with a spacing of 125 mm or 150 mm, and deformed reinforcing bars of SD345 and D13 (designation) are used for the deck distribution reinforcements 25, with a spacing of 125 mm.

[0027] The first upper joint reinforcing bar 22A protruding from the first joint end face 21A of the first precast floor slab 2A is, for example, the portion of the slab main reinforcement 24 arranged in the upper stage of the first precast floor slab 2A that protrudes from the first joint end face 21A and is arranged in the joint space S1. Similarly, the first lower joint reinforcing bar 23A of the first precast floor slab 2A is, for example, the portion of the slab main reinforcement 24 arranged in the lower stage of the first precast floor slab 2A that protrudes from the first joint end face 21A and is arranged in the joint space S1. Note that the first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A were implanted into the first joint end face 21A separately from the slab main reinforcement 24 of the first precast floor slab 2A. The reinforcing bars used for each joint reinforcing bar 22A, 22B, 23A, 23B and their spacing are not particularly limited, but an example is a mode in which deformed reinforcing bars of SD345 and D19 (designation) are used and the spacing is 150 mm. Also, one example is a mode in which the spacing of the reinforcing bars for each joint reinforcing bar 22A, 22B, 23A, 23B is 8 times or less the diameter of the reinforcing bars, for example, in the range of 6 to 8 times the diameter of the reinforcing bars.

[0028] Furthermore, the second upper joint reinforcing bar 22B protruding from the second joint end surface 21B of the second precast floor slab 2B is, for example, the portion of the slab main reinforcement bars 24 arranged in the upper stage of the second precast floor slab 2B that protrudes from the second joint end surface 21B and is arranged in the joint space S1. Similarly, the second lower joint reinforcing bar 23B of the second precast floor slab 2B is, for example, the portion of the slab main reinforcement bars 24 arranged in the lower stage of the second precast floor slab 2B that protrudes from the second joint end surface 21B and is arranged in the joint space S1. Note that the second upper joint reinforcing bar 22B and the second lower joint reinforcing bar 23B may be implanted into the second joint end surface 21B separately from the slab main reinforcement bars 24 of the second precast floor slab 2B. 1 and 2, the first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A protrude perpendicularly from the first joint end face 21A and extend parallel to the joint direction (X direction, bridge axis direction), but the configuration of the first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A is not limited to this. The first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A may protrude from the first joint end face 21A with their reinforcing bar axes extending obliquely relative to the joint direction (bridge axis direction), and the joint reinforcing bars 22A, 23A extending obliquely in this manner may each be arranged in a direction perpendicular to the bridge axis. Similarly, the second upper joint reinforcing bar 22B and the second lower joint reinforcing bar 23B in the second precast deck 2B may protrude from the second joint end face 21B in a position where the axis direction of the reinforcing bar extends obliquely relative to the joint direction (bridge axis direction), and the joint reinforcing bars 22B, 23B extending obliquely in this manner may each be arranged in a direction perpendicular to the bridge axis.

[0029] A shear key 26 is provided on the first joint end face 21A of the first precast floor slab 2A and the second joint end face 21B of the second precast floor slab 2B. The shear key 26 is formed near the center of the height direction of the first joint end face 21A and the second joint end face 21B. For example, the shear key 26 is formed as a recess, which improves stress transfer between the fiber-reinforced filler cast in the joint space S1 and each of the precast floor slabs 2A, 2B.

[0030] In the deck joint structure 1, the first upper joint reinforcing bars 22A and the first lower joint reinforcing bars 23A in the first precast deck slab 2A are arranged in multiple rows in the joint-orthogonal direction (Y direction, direction orthogonal to the bridge axis). In this embodiment, the first upper joint reinforcing bars 22A and the first lower joint reinforcing bars 23A are arranged vertically side by side. Herein, "vertically arranged" means that the upper and lower joint reinforcing bars are arranged vertically side by side at the same position in the joint-orthogonal direction (deck slab width direction), and that paired joint reinforcing bars in the upper and lower rows overlap in plan view. Hereinafter, this type of joint reinforcing bar installation mode will be referred to as "vertically arranged." The first upper joint reinforcing bars 22A and the first lower joint reinforcing bars 23A are arranged at regular intervals in the joint-orthogonal direction (Y direction, direction orthogonal to the bridge axis).

[0031] Similarly, for the second precast slab 2B, multiple second upper joint reinforcing bars 22B and second lower joint reinforcing bars 23B are arranged at regular intervals in the joint-orthogonal direction (Y direction, direction orthogonal to the bridge axis). The second upper joint reinforcing bars 22B and second lower joint reinforcing bars 23B are arranged vertically, and the second upper joint reinforcing bars 22B and second lower joint reinforcing bars 23B overlap in a plan view. That is, the second upper joint reinforcing bars 22B and second lower joint reinforcing bars 23B in the second precast slab 2B are also arranged vertically. However, the vertical arrangement of the joint reinforcing bars in each precast slab 2A, 2B is given as an example, and the installation pattern is not particularly limited. For example, a staggered arrangement may be adopted, as described in a modified example below.

[0032] Here, the reinforcing bar spacing in the joint orthogonal direction (Y direction, direction orthogonal to the bridge axis) of the first upper joint reinforcing bar 22A, the first lower joint reinforcing bar 23A, the second upper joint reinforcing bar 22B, and the second lower joint reinforcing bar 23B is equal to one another. In the deck slab joint structure 1, the first upper joint reinforcing bar 22A protruding from the upper part of the first joint end face 21A of the first precast deck slab 2A and the second upper joint reinforcing bar 22B protruding from the upper part of the second joint end face 21B of the second precast deck slab 2B are arranged alternately (alternately) in the joint orthogonal direction (Y direction) in a plan view. In other words, the first upper joint reinforcing bar 22A protruding from the upper part of the first joint end face 21A and the second upper joint reinforcing bar 22B protruding from the upper part of the second joint end face 21B are arranged in a staggered pattern in the joint space S1.

[0033] Similarly, the first lower joint reinforcing bars 23A protruding from the lower stage of the first joint end face 21A in the first precast floor slab 2A and the second lower joint reinforcing bars 23B protruding from the lower stage of the second joint end face 21B in the second precast floor slab 2B are arranged alternately (alternately) in the joint orthogonal direction (Y direction) in a plan view. In other words, the first lower joint reinforcing bars 23A protruding from the lower stage of the first joint end face 21A and the second lower joint reinforcing bars 23B protruding from the lower stage of the second joint end face 21B are arranged in a staggered manner in the joint space S1. In addition, the joint length where adjacent first upper joint reinforcing bar 22A and second upper joint reinforcing bar 22B overlap in the joint direction (X direction) in the joint space S1, and the joint length where adjacent first lower joint reinforcing bar 23A and second lower joint reinforcing bar 23B overlap in the joint direction (X direction) (joint length of an open lap joint) are not particularly limited, but examples include a range of 5 to 15 times.

[0034] Furthermore, the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B are arranged at the same height in the joint space S1, and the second upper joint reinforcing bars 22B are arranged near the middle between the first upper joint reinforcing bars 22A that are adjacent in the joint orthogonal direction (Y direction). In other words, the first upper joint reinforcing bars 22A are arranged near the middle between the second upper joint reinforcing bars 22B that are adjacent in the joint orthogonal direction (Y direction). Furthermore, the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B are arranged at the same height in the joint space S1, and the second lower joint reinforcing bars 23B are arranged near the middle between the first lower joint reinforcing bars 23A that are adjacent in the joint orthogonal direction (Y direction). In other words, the first lower joint reinforcing bars 23A are arranged near the middle between the second lower joint reinforcing bars 23B that are adjacent in the joint orthogonal direction (Y direction).

[0035] As shown in FIGS. 1 to 3 , anchors 3 are formed at the tip end of each joint reinforcing bar 22A, 22B, 23A, and 23B. The anchors 3 are formed by fixing steel plates to the tip end of each joint reinforcing bar 22A, 22B, 23A, and 23B. The method for fixing the anchors 3 to each joint reinforcing bar 22A, 22B, 23A, and 23B is not particularly limited, and they may be fixed by welding or screws, for example. For example, threads may be formed on the tip end of each joint reinforcing bar 22A, 22B, 23A, and 23B, and the anchors 3 may be formed by nuts screwed onto the threaded portions. The anchors 3 have a larger cross section than the cross sections of each joint reinforcing bar 22A, 22B, 23A, and 23B. In other words, the diameter (outer diameter) of the anchors 3 is relatively larger than the diameter (outer diameter) of each joint reinforcing bar 22A, 22B, 23A, and 23B.

[0036] The planar shape of the anchor 3 is not particularly limited, but it is preferable that it have a circular plate shape. By using a circular plate-shaped anchor 3, when installing the second precast deck 2B after installing the first precast deck 2A, the anchors 3 provided at the tips of each joint steel bar 22A, 22B, 23A, 23B are less likely to interfere with each other. In addition, the joint space S1 shown in Figures 1 and 2 will eventually be filled (cast) with fiber-reinforced filler, and by making the anchor 3 circular, air bubbles are less likely to accumulate around the side periphery of the anchor 3. The size and thickness of the anchor 3 are not particularly limited, but one example is to use a circular steel plate with a diameter of 57 mm and a thickness of 19 mm. In addition, the joint direction (X direction) between the tip surface of the anchor 3 formed on the tip side of the first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A protruding from the first joint end surface 21A in the first precast floor slab 2A and the second joint end surface 21B facing the tip surface ) may be within a range of 5 mm or more and less than 45 mm, and may be 20 mm, for example. Similarly, the distance in the joint direction (X direction) between the tip surfaces of the anchors 3 formed at the tip ends of the second upper joint reinforcing bars 22B and the second lower joint reinforcing bars 23B protruding from the second joint end surface 21B in the second precast floor slab 2B and the first joint end surface 21A opposite to these tip surfaces may be within a range of 5 mm or more and less than 45 mm, and may be 20 mm, for example.

[0037] Furthermore, the deck joint structure 1 includes upper reinforcing bars 27A and lower reinforcing bars 27B arranged in the joint space S1. The upper reinforcing bars 27A and lower reinforcing bars 27B are shear reinforcing bars extending linearly in the direction perpendicular to the joint (Y direction). In the example shown in Figures 1 and 2, one upper reinforcing bar 27A and one lower reinforcing bar 27B are arranged in the joint space S1. However, multiple upper reinforcing bars 27A and multiple lower reinforcing bars 27B may be arranged at intervals in the width direction (X direction) of the joint space S1 depending on the width dimension (dimension in the X direction) of the joint space S1. The reinforcing bars used for the upper reinforcing bars 27A and the lower reinforcing bars 27B are not particularly limited, but examples include deformed reinforcing bars of SD345 and D16 (designation).

[0038] The upper reinforcing bars 27A are arranged along the upper sides of the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B, which are arranged alternately (alternately) in a plan view in the joint space S1, so as to intersect in a direction perpendicular to these bars. The upper reinforcing bars 27A are bound together at the intersections with the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B using binding wires or the like, for example.

[0039] On the other hand, the lower reinforcing bar 27B is arranged along the underside of the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B, which are arranged alternately (alternately) in a plan view in the joint space S1, so as to intersect in a direction perpendicular to these. The lower reinforcing bar 27B is integrally tied to the first lower joint reinforcing bar 23A at the intersection with the first lower joint reinforcing bar 23A using a tie wire or the like. The lower reinforcing bar 27B may be tied to the first lower joint reinforcing bar 23A at the intersection with the second lower joint reinforcing bar 23B, but in this example, the lower reinforcing bar 27B is tied only to the first lower joint reinforcing bar 23A.

[0040] The deck joint structure 1 configured as described above joins the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B protruding from the respective joint end faces 21A, 21B of the oppositely installed first precast deck 2A and second precast deck 2B, and the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B, using open lap joints. The open lap joint is formed by overlapping the tip portions of the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B (first lower joint reinforcing bar 23A and second lower joint reinforcing bar 23B) in the axial direction while leaving a gap between them, thereby joining the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B, and the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B together through the adhesion force between the fiber-reinforced interfill material poured into the joint space S1 and each joint reinforcing bar 22A, 22B, 23A, 23B.

[0041] FIG. 4 is a diagram showing the state in which the first precast deck 2A and the second precast deck 2B are connected by filling (casting) the joint space S1 with fiber reinforced filler 4. Reference numeral 5 denotes a joint portion formed by filling (casting) the joint space S1 with fiber reinforced filler 4. The fiber reinforced filler 4 is high-strength concrete or mortar containing reinforcing fibers (hereinafter referred to as "fiber"). The design standard strength of the fiber reinforced filler 4 is not particularly limited. For example, the design standard strength of the fiber reinforced filler 4 may be set to 50 N / mm 2 or more, and the design standard strength is 100 N / mm 2 The above-mentioned ultra-high strength fiber reinforced filler may be used. Also, the fiber reinforced filler 4 may contain fibers in a volume ratio of 0.5% or more. In this embodiment, the strength ratio of the fiber reinforced filler 4 (floor slab concrete strength) to the concrete strength of the precast slab 2 is It is preferable that the ratio (crete strength / filling material strength) is 0.5 or more. Furthermore, it is preferable to add an expansive material, a shrinkage reducing agent, etc. to the fiber reinforced filler 4. By doing so, it is possible to suppress or reduce the occurrence of cracks caused by shrinkage of the fiber reinforced filler 4 filled (cast) in the joint space S1.

[0042] Next, we will explain the construction procedure (deck slab joint method) of the deck slab joint structure 1. Figure 5 is a diagram explaining the construction procedure (deck slab joint method) of the deck slab joint structure 1. The construction procedure (deck slab joint method) of the deck slab joint structure 1 includes a preparation process (S01), a first deck slab installation process (S02), a second deck slab installation process (S03), an upper reinforcing bar arrangement process (S04), a pouring process (S05), etc.

[0043] First, in the preparation step (S01), a first precast deck 2A and a second precast deck 2B are prepared to be connected using the deck joint structure 1. The first precast deck 2A and the second precast deck 2B are as described in Figures 1 to 3. .

[0044] FIG. 6 is a diagram illustrating the first precast slab 2A and the second precast slab 2B prepared in the preparation step (S01). For example, the first precast slab 2A and the second precast slab 2B are transported to the vicinity of the construction site by a construction vehicle such as a truck. The first precast slab 2A is the precast slab that is installed at the installation site prior to the second precast slab 2B. The first precast slab 2A has one lower reinforcing bar 27B arranged along the joint orthogonal direction (the slab width direction) so as to align with the underside of multiple first lower joint reinforcing bars 23A protruding from the first joint end face 21A. In other words, the lower reinforcing bar 27B is pre-tied to the first lower joint reinforcing bars 23A at multiple locations, below each first lower joint reinforcing bar 23A and perpendicular to the underside of the first lower joint reinforcing bars 23A.

[0045] In this way, the process of arranging and fastening the lower reinforcing bars 27B along the underside of the plurality of first lower joint reinforcing bars 23A in the first precast slab 2A is specified as the "lower reinforcing bar arrangement process." The "lower reinforcing bar arrangement process" is performed at least prior to the second slab installation process (S03), but in this example, the "lower reinforcing bar arrangement process" is included in the preparation process (S01). The pre-fastening of the lower reinforcing bars 27B to the first lower joint reinforcing bars 23A of the first precast slab 2A may be completed in advance at a manufacturing plant that manufactures the precast slab before the slab is shipped. Alternatively, the work of fastening the lower reinforcing bars 27B to the first lower joint reinforcing bars 23A may be performed after the first precast slab 2A is transported to the construction site. In this procedure, before the first precast floor slab 2A is installed in a predetermined installation position, the lower reinforcing bars 27B are attached in advance to the first lower joint reinforcing bars 23A of the first precast floor slab 2A. Note that in the preparation process (S01) shown in Fig. 6, the first precast floor slab 2A and the second precast floor slab 2B are not installed in a predetermined installation position described later, but are temporarily placed, for example, on the loading platform of a trailer or in an appropriate location in the work area.

[0046] Also, as shown in Figure 6, at the time of the preparation process (S01), the upper reinforcing bars 27A described in Figures 1 to 3 have not been arranged in the first precast floor slab 2A and the second precast floor slab 2B.

[0047] Next, in the first deck installation step (S02), the first precast deck 2A is installed at a predetermined installation position P1, as shown in Figure 7(A). The deck slab can be lifted and installed using a dedicated deck installation machine or a lifting device such as a crane truck. When the first precast deck slab 2A is installed at the installation position P1, the lower reinforcing bars 27B have already been arranged and tied together along the underside of the first lower joint reinforcing bars 23A.

[0048] Next, in the second deck installation step (S03), the second precast concrete is installed as shown in FIG. The second precast floor slab 2B is installed at a predetermined installation position P2. The second precast floor slab 2B is installed at a distance from the first joint end surface 21A of the first precast floor slab 2A so that a joint space S1 is formed between the first joint end surface 21A and the second joint end surface 21B of the first precast floor slab 2A installed at installation position P1. As described above, the first upper joint reinforcing bars 22A and the first lower joint reinforcing bars 23A of the first precast floor slab 2A are arranged vertically side by side. Therefore, vertically extending gaps are formed between adjacent first upper joint reinforcing bars 22A and adjacent first lower joint reinforcing bars 23A in the deck width direction.

[0049] Meanwhile, in the second precast floor slab 2B, the second upper joint reinforcing bars 22B and the second lower joint reinforcing bars 23B are also arranged vertically, so that gaps extending vertically are formed between adjacent second upper joint reinforcing bars 22B in the floor slab width direction and between adjacent second lower joint reinforcing bars 23B. Therefore, in the second floor slab installation step (S03), the second precast floor slab 2B lifted by the lifting device is lowered to the installation position P2, and the second precast floor slab 2B is hung down from above so that the second upper joint reinforcing bars 22B are inserted from above into the gaps between the first upper joint reinforcing bars 22A adjacent in the joint orthogonal direction in the first precast floor slab 2A.

[0050] This allows the second precast floor slab 2B to be smoothly installed at the installation position P2 without the second lower joint reinforcing bars 23B of the second precast floor slab 2B interfering with (colliding with) the first upper joint reinforcing bars 22A of the first precast floor slab 2A. As described with reference to Figures 1 to 3, the first upper joint reinforcing bars 22A of the first precast floor slab 2A and the second upper joint reinforcing bars 22B of the second precast floor slab 2B can be arranged alternately (staggered) in the slab width direction (the direction perpendicular to the joints) in a plan view. Similarly, the first lower joint reinforcing bars 23A of the first precast floor slab 2A and the second lower joint reinforcing bars 23B of the second precast floor slab 2B can be arranged alternately (staggered) in the slab width direction (the direction perpendicular to the joints) in a plan view.

[0051] Furthermore, in this embodiment, at the completion of the second slab installation step (S03), the second lower joint reinforcing bars 23B of the second precast slab 2B are positioned at the same height as the first lower joint reinforcing bars 23A of the first precast slab 2A. Therefore, the plurality of second lower joint reinforcing bars 23B of the second precast slab 2B can be placed in abutting contact with the lower reinforcing bars 27B that have been previously arranged and tied along the underside of the first lower joint reinforcing bars 23A of the first precast slab 2A. In other words, the second precast slab 2B can be installed so that the lower reinforcing bars 27B are along the underside of the plurality of second lower joint reinforcing bars 23B. As a result, at the completion of the second slab installation step (S03), the lower reinforcing bars 27B are positioned along the underside of the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B so as to alternately cross them.

[0052] Next, in the upper reinforcing bar arrangement step (S04), as shown in FIG. 7(C), upper reinforcing bars 27A are arranged so as to be aligned with the upper sides of the first upper joint reinforcing bars 22A in the first precast floor slab 2A and the second upper joint reinforcing bars 22B in the second precast floor slab 2B. The upper reinforcing bars 27A are arranged so as to be perpendicular to the extension direction of the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B, which are arranged alternately (in a staggered pattern) in the floor slab width direction (the joint-perpendicular direction). In this embodiment, at the completion of the second floor slab installation step (S03), the second upper joint reinforcing bars 22B of the second precast floor slab 2B are arranged at the same height as the first upper joint reinforcing bars 22A of the first precast floor slab 2A. Therefore, upper reinforcing bars 27A can be easily arranged in a state where they are in contact with both first upper joint reinforcing bars 22A and second upper joint reinforcing bars 22B. Upper reinforcing bars 27A are appropriately tied together at the points where they intersect with first upper joint reinforcing bars 22A and second upper joint reinforcing bars 22B.

[0053] 1 to 3, the joint space S1 is ready to be filled (cast) with the fiber reinforced space filler 4. Before filling (casting) the fiber reinforced space filler 4 into the joint space S1, formwork is installed on the sides, bottom, etc. of the joint space S1 as needed to prevent the fiber reinforced space filler 4 from leaking out of the joint space S1.

[0054] Next, in the casting step (S05) shown in Figure 5, fiber-reinforced spacer 4 is filled (cast) into the joint space S1. As a result, the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B, and the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B are joined together with open lap joints via the fiber-reinforced spacer 4 filled into the joint space S1, and the first precast deck 2A and the second precast deck 2B can be connected in the joint direction (bridge axis direction). After completion of the casting step (S05), the fiber-reinforced spacer 4 filled into the joint space S1 is cured as appropriate, and the formwork is removed once the required strength is achieved.

[0055] In the above construction procedure, for convenience, the procedure for connecting a set of first precast deck 2A and second precast deck 2B has been explained, but it goes without saying that three or more precast decks 2 can also be connected in the bridge axis direction by laying three or more precast decks 2 in the bridge axis direction and filling (pouring) fiber-reinforced interfacial material 4 into the joint spaces S1 formed between each precast deck 2.

[0056] For example, in the example shown in Figure 8, three precast decks 2 are laid in the bridge axis direction. The shape of each precast deck 2 is illustrated in a simplified form. The laying direction D1 shown in the figure indicates the direction in which the laying work of the precast deck 2 proceeds along the bridge axis direction. That is, in this example, the laying and connection work of the precast deck slabs 2 proceeds sequentially toward the laying direction D1. Of each precast deck slab 2, the front end face located on the side of the laying direction D1 is formed as the above-mentioned first joint end face 21A, from which the first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A protrude. On the other hand, of each precast deck slab 2, the rear end face located on the opposite side from the laying direction D1 is formed as the second joint end face 21B, from which the second upper joint reinforcing bar 22B and the second lower joint reinforcing bar 23B protrude.

[0057] In the example shown in FIG. 8, three precast slabs 2, labeled F1, F2, and F3, are laid from rear to rear along the laying direction D1. The slab labeled F1 is referred to as the front precast slab 2 (F1), the slab labeled F2 is referred to as the middle precast slab 2 (F2), and the slab labeled F3 is referred to as the rear precast slab 2 (F3). In the example shown in FIG. 7, the front end surface (first joint end surface 21A) of the front precast slab 2 (F1) is connected to the rear end surface (second joint end surface 21B) of the middle precast slab 2 (F2). The front end surface (first joint end surface 21A) of the middle precast slab 2 (F2) is connected to the front end surface (first joint end surface 21A) of the rear precast slab 2 (F3).

[0058] Therefore, if the first precast deck 2A and the second precast deck 2B described in Figures 1 to 3 are applied to each deck F1 to F3, and considering the connection relationship between the front precast deck 2 (F1) and the middle precast deck 2 (F2), the front precast deck 2 (F1), which is laid relatively first, corresponds to the above-mentioned first precast deck 2A, and the middle precast deck 2 (F2), which is laid following the front precast deck 2 (F1), corresponds to the above-mentioned second precast deck 2B. On the other hand, when considering the connection relationship between the middle precast deck 2 (F2) and the rear precast deck 2 (F3), the middle precast deck 2 (F2), which is laid relatively first, corresponds to the first precast deck 2A described above, and the rear precast deck 2 (F3), which is laid following the middle precast deck 2 (F2), corresponds to the second precast deck 2B described above.

[0059] Referring to Figure 9, the laying procedure for each deck slab F1 to F3 will be explained. First, as shown in (A), First, the first precast slab 2 (F1) is installed, then the middle precast slab 2 (F2) is installed with a gap in front of the first precast slab 2 (F1) (on the side of the laying direction D1) as shown in (B), and then the second precast slab 2 (F3) is installed with a gap in front of the middle precast slab 2 (F2) (on the side of the laying direction D1) as shown in (C). At the time of installing each of the slabs F1 to F3, the lower reinforcing bars 27B have already been attached to the first lower joint reinforcing bars 23A protruding from the first joint end faces 21A of each of the slabs F1 to F3, as explained in the construction procedure of Figure 5.

[0060] Symbol S1-1 denotes a joint space formed between the front precast deck 2 (F1) and the middle precast deck 2 (F2), and symbol S1-2 denotes a joint space formed between the middle precast deck 2 (F2) and the rear precast deck 2 (F3). After installation of the middle precast deck 2 (F2) is completed, upper reinforcing bars 27A are arranged in the joint space S1-1. Then, the front precast deck 2 (F1) and the middle precast deck 2 (F2) are connected by filling (casting) fiber-reinforced filler 4 into the joint space S1-1. Similarly, after installation of the rear precast deck 2 (F3) is completed, upper reinforcing bars 27A are arranged in the joint space S1-2. Thereafter, the middle precast deck 2 (F2) and the rear precast deck 2 (F3) are connected by filling (casting) the joint space S1-2 with fiber-reinforced spacer 4. Note that the filling (casting) of the fiber-reinforced spacer 4 into the joint space S1-1 and the joint space S1-2 may be performed simultaneously or successively.

[0061] In the deck joint structure 1 configured as described above, the strength of the joint portion 5 can be significantly improved by the synergistic effect of the formation of compression struts by the anchors 3 formed at the tips of each joint reinforcing bar 22A, 22B, 23A, 23B, the restraining effect of each joint reinforcing bar 22A, 22B, 23A, 23B by the upper reinforcing bar 27A and the lower reinforcing bar 27B, and the stress transmission by the fiber-reinforced interfill material 4.

[0062] When a load acts on the precast deck 2 connected by the deck joint structure 1, a tensile force acts on each of the joint reinforcing bars 22A, 22B, 23A, 23B arranged in the joint section 5. The first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B in the joint section 5, and the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B are joined by open lap joints with hardened fiber-reinforced spacer 4 interposed therebetween. The tensile force acting on each of the joint reinforcing bars 22A, 22B, 23A, 23B is transmitted to the joint section 5 (the hardened fiber-reinforced spacer 4) via the anchors 3 provided at the tip, and the anchors 3 compress the joint section 5 (the hardened fiber-reinforced spacer 4). In the joint portion 5 (fiber-reinforced interfacial material 4 after hardening), the area where the anchor 3 compresses the fiber-reinforced interfacial material 4 when a tensile force acts on each joint reinforcing bar 22A, 22B, 23A, 23B is formed, for example, in a cone shape starting from the anchor 3.

[0063] Figure 10 is a schematic diagram showing the compression strut region CS where compression struts are formed by the action of the anchors 3 when a tensile force is applied to each of the joint reinforcing bars 22A, 22B, 23A, 23B. In reality, when a tensile force is applied to each of the joint reinforcing bars 22A, 22B, 23A, 23B, cone-shaped compression struts are formed in the hardened fiber-reinforced filler 4, but in Figure 10, the region where compression struts formed between adjacent joint reinforcing bars 22A, 22B and 23A, 23B in the slab width direction (direction perpendicular to the joint) overlap is shown two-dimensionally as the compression strut region CS. That is, the compression struts are compression bundles formed between the anchors 3 provided on the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B that are adjacent in the direction perpendicular to the joint, and between the anchors 3 provided on the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B that are adjacent in the direction perpendicular to the joint, when a tensile force acts on each joint reinforcing bar 22A, 22B, 23A, 23B. In the joint part 5, a set of anchors 3 that are adjacent in the direction perpendicular to the joint and face each other compress from both sides the hardened fiber reinforced interfill 4 that is interposed in the area sandwiched between them. Struts (compression bundles) are formed, and the region where the compression struts (compression bundles) are formed corresponds to the compression strut region CS.

[0064] Here, the symbol W1 in Figure 10 is the gap width. The gap width W1 is the dimension along the joint direction (bridge axis direction) at the joint portion 5. The gap width W1 is equal to the distance in the joint direction (bridge axis direction) between the first joint end face 21A of the first precast deck 2A (more specifically, the portion of the first joint end face 21A where the shear key 26 is not formed) and the second joint end face 21B of the second precast deck 2B (more specifically, the portion of the second joint end face 21B where the shear key 26 is not formed). The gap width W1 is not particularly limited, but an example is one in which it is 130 mm or more and 160 mm or less. 10 is the "joint reinforcing bar lap length" of the joint reinforcing bars adjacent to each other in the deck width direction (direction perpendicular to the joint) (i.e., the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B, and the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B) overlapping in the joint direction (bridge axis direction). In this embodiment, an example is given in which the joint reinforcing bar lap length is 100 mm or more.

[0065] Details will be explained in the verification by anchorage test later, but the average cross-sectional area of ​​each compression strut region CS formed between adjacent joint reinforcing bars 22A, 22B and between adjacent joint reinforcing bars 23A, 23B is 560 mm 3 / mm] or more is preferable from the viewpoint of ensuring sufficient joint strength of the deck joint structure 1. Here, the average cross-sectional area of ​​the compression strut region CS is calculated as the value obtained by dividing the volume corresponding to each compression strut region CS formed between adjacent joint reinforcing bars 22A, 22B and 23A, 23B in the deck width direction (direction perpendicular to the joint) by the joint reinforcing bar lap length L1. In other words, the average cross-sectional area of ​​the compression strut region CS has the significance of being the average cross-sectional area of ​​the compression strut region CS in the section where adjacent joint reinforcing bars 22A, 22B and 23A, 23B are overlapped in the joint direction (bridge axis direction). The compression strut region CS can be regarded as the region where stress is transmitted to each other between the joint reinforcing bars 22A, 22B and between the joint reinforcing bars 23A, 23B, which are open-lap spliced ​​via the hardened fiber-reinforced filler 4 in the joint section 5. Therefore, the larger the average cross-sectional area of ​​the compression strut region CS, the greater the stress that can be transmitted between them via the fiber-reinforced interfacial material 4, thereby increasing the joint strength of the deck joint structure 1.

[0066] The area of ​​the compression strut region CS is determined by parameters such as the area of ​​the anchorage 3, the spacing of the joint rebars, and the joint rebar lap length L1 between adjacent joint rebars. In other words, the volume of each compression strut region CS can be calculated based on the geometric relationship between these parameters. In this embodiment, the volume of the compression strut region CS is calculated by setting the angle θ (compression strut formation angle) between the compression strut region CS and the axial direction (joint direction) of each joint rebar 22A, 22B, 23A, 23B to 33°.

[0067] As for the parameters related to the volume of the compression strut region CS, the larger the area of ​​the anchor 3, the smaller the reinforcing bar spacing, and the longer the joint reinforcing bar lap length L1, the larger the volume and average cross-sectional area of ​​the compression strut region CS can be. Therefore, by appropriately changing these parameters, it is possible to design the joint portion 5 so that an appropriate size of compression strut region CS is formed. In the deck joint structure 1 of this embodiment, the average cross-sectional area of ​​the compression strut region CS is preferably 560 mm3 The joint reinforcing bars 22A, 22B, 23A, and 23B are arranged in the joint portion 5 so that the average cross-sectional area of ​​the compression strut region CS is 560 mm / mm or more. 3 It is preferable that the reinforcing bar arrangement design for each of the joint reinforcing bars 22A, 22B, 23A, 23B is carried out so that the reinforcing bar arrangement is equal to or greater than 1 / mm.

[0068] Furthermore, according to the deck joint structure 1 of this embodiment, the joint portion 5 is provided with the upper reinforcing bar 27A and the lower reinforcing bar 27B (shear reinforcing bar), which can restrain each joint reinforcing bar 22A, 22B, 23A, 23B from above and below. When each joint reinforcing bar 22A, 22B, 23A, 23B, which has an anchoring body 3 formed thereon, is joined using an open lap joint, the synergistic effect of restraining each joint reinforcing bar 22A, 22B, 23A, 23B with the upper reinforcing bar 27A and the lower reinforcing bar 27B (shear reinforcing bar) is significant, and the strength of the joint portion 5 can be suitably improved. In other words, because the deck slab joint structure 1 includes the upper reinforcing bar 27A and the lower reinforcing bar 27B (shear reinforcing bar) in the joint portion 5, it is possible to increase the reinforcing bar pitch of the joint reinforcing bars without reducing the strength of the joint portion compared to conventional deck slab joint structures using open lap joints, or to reduce the gap width by reducing the joint reinforcing bar lap length L1 of the open lap joint. As a result, it is possible to reduce construction costs and improve workability.

[0069] In particular, according to the deck joint structure 1, the lower reinforcing bars 27B provided in the joint portion 5 are arranged along the undersides of the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B, which are arranged alternately (alternately) in a plan view. This structure not only provides the strength advantage of being able to restrain the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B of the joint portion 5 from below, but also provides the following advantage of improved workability. That is, according to the above structure, as explained in Figures 5 to 7, the lower reinforcing bars 27B can be tied to the first lower joint reinforcing bars 23A in advance during construction. In other words, after the second precast slab 2B is installed at installation position P2 following the first precast slab 2A installed at installation position P1, each joint reinforcing bar 22A, 22B, 23A, 23B is arranged in the joint space S1. Arranging the lower reinforcing bar 27B in this state can be time-consuming, but in this embodiment, the reinforcing bar arrangement work of the lower reinforcing bar 27B is completed before installing at least the second precast slab 2B at installation position P2, which provides excellent workability. From the perspective of workability, it is particularly preferable to pre-attach the lower reinforcing bar 27B to the first lower joint reinforcing bar 23A before shipping the first precast slab 2A from the manufacturing factory, or to perform this before installing the first precast slab 2A at installation position P1 after delivery to the construction site.

[0070] Furthermore, in the deck joint structure 1, the upper reinforcing bars 27A provided in the joint portion 5 are arranged along the upper sides of the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B that are arranged alternately (alternately) in a plan view. With this structure, in addition to the strength advantage of being able to restrain the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B of the joint portion 5 from above, the following advantages of improved workability are obtained. In other words, according to the above structure, after installing the first precast deck 2A and the second precast deck 2B at their respective installation positions P1, P2, the upper reinforcing bars 27A are placed so as to intersect on top of the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B arranged in a staggered pattern in the joint space S1, and then the upper reinforcing bars 27A are simply tied to the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B at each intersection, resulting in extremely excellent workability.

[0071] Furthermore, in the deck slab joint structure 1, the first upper joint reinforcing bars 22A and the first lower joint reinforcing bars 23A in the first precast deck slab 2A are arranged side by side vertically, and the second upper joint reinforcing bars 22B and the second lower joint reinforcing bars 23B in the second precast deck slab 2B are arranged side by side vertically. In a plan view of the joint portion 5, the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B are arranged alternately (staggered) in the direction perpendicular to the joint, and the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B are arranged alternately (staggered) in the direction perpendicular to the joint. According to this, when the second precast deck 2B is installed at a distance from the first precast deck 2A in the joint direction, the joint reinforcing bars 22A, 23A on the first precast deck 2A side and the joint reinforcing bars 22B, 23B on the second precast deck 2B side are less likely to interfere with or collide with each other, thereby realizing a deck joint structure 1 with excellent workability.

[0072] Furthermore, in the deck joint structure 1, the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B are arranged at the same height in the joint portion 5. According to this structure, By simply installing the second precast floor slab 2B following the first precast floor slab 2A, which has had the lower reinforcing bars 27B previously fastened to the second lower joint reinforcing bars 23B, the lower reinforcing bars 27B can be attached to the underside of the second lower joint reinforcing bars 23B in the second precast floor slab 2B. Furthermore, in the deck slab joint structure 1, the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B are arranged at the same height in the joint section 5. With this structure, the upper reinforcing bars 27A can be arranged simply by placing them on top of the first upper joint reinforcing bars 22A and second upper joint reinforcing bars 22B, which are arranged in a staggered pattern in the joint space S1, and the work of fastening the upper reinforcing bars 27A to the first upper joint reinforcing bars 22A and second upper joint reinforcing bars 22B can also be easily performed.

[0073] As described above, the deck slab joint structure 1 according to this embodiment can provide a technique for a precast deck slab joint structure in which the joint portion 5 has excellent strength while saving labor during construction.

[0074] Next, the results of an anchorage test conducted on the deck slab joint structure 1 of this embodiment will be described. The anchorage test was conducted using a load test device 100 shown in FIG. 11 and multiple specimens TS (Cases 1 to 8, described later) simulating the deck slab joint structure 1 shown in FIG. 4 were prepared. FIG. 12 is a diagram illustrating the specimens TS used in the anchorage test. FIG. 13 shows the materials used to fabricate the specimens TS. FIG. 14 shows the specifications of each case in the specimens TS. FIG. 15 shows the composition of the fiber-reinforced filler used to fabricate the specimens TS. The joints 5 (cured fiber-reinforced filler 4) in the specimens TS had a length of 390 mm, a thickness of 220 mm, and four widths of 120 mm, 130 mm, 140 mm, and 150 mm. The thickness of the specimens TS corresponded to the thickness of the joints 5, and the width corresponded to the filler width W1 of the joints 5 (see FIG. 10).

[0075] The test specimens TS were fabricated by arranging two splice bars RB1 on one side of the joint 5 (the hardened fiber-reinforced spacer 4) in a staggered pattern, with the tip, including the anchor 3, embedded in the joint 5 (the hardened fiber-reinforced spacer 4). While the splice bars of each precast deck 2 in the thickness direction are arranged in two rows, one above the other, in the test specimens TS for this test, the splice bars RB1 and RB2 were arranged in a single row for simplicity. The cover thickness of the anchor 3 for each splice bar RB1 and RB2 was standardized to 20 mm (constant) for all test specimens TS. Therefore, the splice bar lap length L1 between adjacent splice bars RB1 and RB2 in the length direction of the joint 5 (the hardened fiber-reinforced spacer 4) was [the width dimension (spacer width W1) of the test specimen (joint 5) - 40 mm].

[0076] Deformed reinforcing bars SD345 (material) and D19 (designation) were used for the joint reinforcing bars RB1 and RB2. In the case with shear reinforcement, deformed reinforcing bars SD345 (material) and D16 (designation) were used as shear reinforcement, and one shear reinforcement was placed along the length of joint section 5 so as to be perpendicular to joint reinforcing bars RB1 and RB2. The shear reinforcement corresponds to upper reinforcing bar 27A (lower reinforcing bar 27B) in deck joint structure 1. Circular steel plates with a diameter of 57 mm were fixed to the ends of joint reinforcing bars RB1 and RB2 as anchors 3. TP nuts (manufactured by Hikarigaoka Kosan Co., Ltd.) were used for anchors 3. Furthermore, the rebar spacing (pitch) PT of the joint rebar RB2 was set to two levels: 125 mm and 150 mm, and the joint rebar RB2 was placed at the center position sandwiched between two joint rebars RB1 in the longitudinal direction of the test specimen TS (joint part 5). The fiber-reinforced filler used to manufacture the test specimen TS had a design standard strength of 100 N / mm 2 High-strength fiber-reinforced concrete was used.

[0077] Then, specimens TS with the specifications for Cases 1 to 8 shown in Figure 14 were prepared, and loading tests were conducted on each. The anchorage test parameters were the rebar spacing PT of the splice rebar RB2, the splice rebar lap length L1, and the presence or absence of shear reinforcement. When fabricating specimens TS, the mixing and placement of the fiber-reinforced interfacial filler were carried out in a test room at a temperature of 20°C and a relative humidity of 60%. (See Figure 16) The loading age of each test specimen TS and the compressive strength test results of the fiber-reinforced filler at each age are shown in the table.

[0078] Next, we will explain the loading device and the loading method for the anchorage test (loading test). The loading method for the anchorage test was to apply force to the joint rebar RB2 (single bar arrangement) protruding from one side of the test specimen TS using a center hole jack, until the standard yield value of the joint rebar RB2 (345 N / mm 2 ) up to 95% of the load (345N / mm 2 x 0.95 x 286.5 mm 2 = 93.9kN) was repeatedly loaded 20 times, and the standard tensile strength (490N / mm 2The load applied to the splice reinforcing bar RB2 was measured using a load cell.

[0079] Figure 17 shows the results of the anchorage tests. As shown in Figure 17, the failure modes for each case were classified into three categories: "cone failure," "cone failure after yield," and "attainment of ultimate load." Cone failure is a failure mode in which the joint section 5 (the hardened fiber-reinforced interfacial filler 4) fractures in a cone shape, causing the joint reinforcing bars RB1 and RB2 to slip out before they reach the standard yield strength (load 93.9 kN). In this anchorage test, Cases 1 and 2 experienced cone failure. "Cone failure after yield" is a failure mode in which the joint reinforcing bars RB1 and RB2 reach the standard yield strength (load 93.9 kN), but before they reach the standard tensile strength (load 140.4 kN), the joint section 5 (the hardened fiber-reinforced interfacial filler 4) fractures in a cone shape, causing the joint reinforcing bars RB1 and RB2 to slip out. In this anchorage test, Case 3 reached cone failure after yielding. Although "reaching ultimate load" is not strictly a failure mode, the loading test was terminated by removing the load from each specimen TS without complete destruction after the joint rebars RB1 and RB2 reached the standard tensile strength (load 140.4 kN) without coming loose. In this anchorage test, Cases 4, 5, 6, 7, and 8 reached "reaching ultimate load." The "judgment" results shown in Figure 17 were "OK" for specimens TS (cases) that reached "reaching ultimate load," and "NG" for all others.

[0080] Here, in Cases 5 to 8 with shear reinforcement, none of them reached cone failure or post-yield cone failure, and the joint reinforcement bars RB1 and RB2 reached the specified tensile strength without fracture of joint 5 (hardened fiber-reinforced interfacial filler 4). In other words, by placing shear reinforcement in joint 5, it was possible to ensure joint strength greater than the specified tensile strength of joint reinforcement bars RB1 and RB2. This is thought to be because the shear reinforcement placed in joint 5 restrained the joint reinforcement bars RB1 and RB2, contributing to an increase in joint strength of joint 5. On the other hand, among Cases 1 to 4 with shear reinforcement, all of Cases 1 to 3, except for Case 4, reached cone failure or post-yield cone failure, and failed to ensure joint strength greater than the specified tensile strength of joint reinforcement bars RB1 and RB2.

[0081] Figure 17 shows the average cross-sectional area (calculated value) of the compression strut region CS for each case. The calculation method for the average cross-sectional area of ​​the compression strut region CS is as explained in Figure 10. As described above, the average cross-sectional area of ​​the compression strut region CS increases with the area of ​​the anchorage 3, the smaller the rebar spacing of the splice rebars, and the longer the splice rebar lap length L1 between adjacent splice rebars. In this test, the area of ​​the anchorage 3 is uniform, so the smaller the rebar spacing PT of the splice rebar RB2 and the longer the splice rebar lap length L1, the larger the average cross-sectional area of ​​the compression strut region CS. Considering the relationship between the average cross-sectional area of ​​the compression strut region CS and the strength of the splice section 5, Cases 1 to 4 all have "no shear reinforcement," but the average cross-sectional area of ​​the compression strut region CS increases in the following order (Case 4 is largest, Case 1 is smallest). If the average cross-sectional area of ​​the compression strut region CS is relatively large, the joint reinforcing bars RB1 and RB2 can withstand a larger load without slipping out due to stress transmission through the compression strut region CS. This allows for the joint to bend, increasing the strength of the joint 5. Therefore, when comparing the maximum loads (strength) of Cases 1 to 4, it was confirmed that the larger the average cross-sectional area of ​​the compression strut region CS, the greater the maximum load (strength). Furthermore, although Case 4 has no shear reinforcement, the average cross-sectional area of ​​the compression strut region CS is very large, so it is thought that the joint strength was greater than or equal to the standard tensile strength of the joint rebar, without reaching cone failure or post-yield cone failure.

[0082] Of course, the smaller the rebar spacing PT of the joint rebar RB2 and the longer the joint rebar lap length L1, the more rebars are placed in the joint section 5, which can lead to overcrowding. Therefore, it is preferable to ensure a joint strength equal to or greater than the standard tensile strength of the joint rebars RB1 and RB2 without excessively increasing the average cross-sectional area of ​​the compression strut region CS, without reaching "cone failure" or "post-yield cone failure." This requirement can be met by placing shear reinforcement in the joint section 5, as in Cases 5 to 8. That is, although Cases 5 to 8 all have "shear reinforcement," the average cross-sectional area of ​​the compression strut region CS is larger in the following order: Case 5, Case 8, Case 6, and Case 7 (Case 5 is the largest, Case 7 is the smallest). Furthermore, among Cases 5 to 8, the case with the smallest average cross-sectional area of ​​the compression strut region CS (560 mm 3 / mm), it can be seen that even in Case 7, "cone fracture" and "post-yield cone fracture" occurred, and joint strength exceeding the standard tensile strength of joint reinforcing bars RB1 and RB2 was secured.

[0083] These results show that by arranging shear reinforcement in the joint 5, it is possible to ensure good joint strength without reaching "cone fracture" or "post-yield cone fracture" without excessively increasing the average cross-sectional area of ​​the compression strut region CS, and from this perspective, the superiority of arranging shear reinforcement in the joint 5 is confirmed. Furthermore, according to the results of this test, from the perspective of ensuring good joint strength of the joint 5, it is recommended to increase the average cross-sectional area of ​​the compression strut region CS to 560 mm 3 The results showed that it is preferable to ensure a thickness of at least / mm.

[0084] In addition, there is no particular requirement for the upper limit of the average cross-sectional area in the compression strut region CS from the viewpoint of joint strength, but from the viewpoint of preventing the joint part 5 from being too densely reinforced and from the viewpoint of workability, the upper limit is set at 1361 mm 3 / mm or less. From the viewpoint of realizing the average cross-sectional area of ​​the compression strut region CS within the above range, it is preferable that the splice rebar lap length L1 between adjacent splice rebars be 80mm or more and 110mm or less. It is also preferable that the value obtained by dividing the net spacing between adjacent splice rebars by the diameter (width) of the anchorage be 1.9 or more and 2.3 or less. The net spacing between adjacent splice rebars is the value obtained by subtracting the diameter of the splice rebar from the spacing (center-to-center spacing) between the splice rebars.

[0085] Based on the findings obtained from the anchorage tests, it has been demonstrated that the deck slab joint structure 1 according to this embodiment is provided with the upper reinforcing bars 27A and the lower reinforcing bars 27B (shear reinforcing bars) to satisfactorily improve the strength of the joint portion 5. In addition, in the joint portion 5, the average cross-sectional area of ​​the compression strut region CS formed between the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B adjacent to each other in the joint perpendicular direction, and between the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B adjacent to each other in the joint perpendicular direction, is set to 560 mm 3 / mm or more. As an example, it is preferable that the average cross-sectional area of ​​the compression strut region CS is 1361 mm 3 / mm or less. Furthermore, from the viewpoint of adjusting the average cross-sectional area of ​​the compression strut region CS within the above range, it is preferable that the joint reinforcing bar lap length L1 between the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B adjacent in the joint perpendicular direction (or between the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B adjacent in the joint perpendicular direction) be 80 mm or more and 110 mm or less, and that the net spacing between the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B adjacent in the joint perpendicular direction (or between the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B adjacent in the joint perpendicular direction) be 1.9 or more and 2.3 or less.

[0086] <Modification> Various modifications of the embodiment will be described below.

[0087] In the deck joint structure 1 according to the embodiment, various configurations can be adopted for the upper reinforcing bars 27A and the lower reinforcing bars 27B (shear reinforcing bars) arranged in the joint space S1 (joint portion 5). For example, FIG. 18 is a diagram illustrating a deck joint structure 1 according to a modified example. Specifically, it shows the deck joint structure 1 according to the modified example viewed from the front, corresponding to FIG. 3. In FIG. 18, the configuration differs from that shown in FIGS. 1 and 2 in that the upper reinforcing bars 27A are arranged below the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B, and the lower reinforcing bars 27B are arranged above the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B. As a further modification, the upper reinforcing bars 27A may be arranged above the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B, and the lower reinforcing bars 27B may be arranged below the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B. Alternatively, the upper reinforcing bars 27A may be arranged below the first upper joint reinforcing bars 22A and the second upper joint reinforcing bars 22B, and the lower reinforcing bars 27B may be arranged above the first lower joint reinforcing bars 23A and the second lower joint reinforcing bars 23B.

[0088] When adopting the above-described modified example, a construction procedure (deck slab joint method) different from the procedure described in Fig. 5 may be adopted. That is, the construction procedure (deck slab joint method) of the deck slab joint structure 1 according to the present disclosure is such that the upper reinforcing bars 27A are arranged so as to be parallel to the first upper reinforcing bars 22A and the second upper reinforcing bars 22B, and the lower reinforcing bars 27B are arranged so as to be parallel to the first lower reinforcing bars 23A and the second lower reinforcing bars 23B, and the filler material is filled into the joint space S1, and various modified examples can be adopted. Therefore, the procedure for arranging the upper reinforcing bars 27A and the lower reinforcing bars 27B is not particularly limited. For example, when constructing the deck joint structure 1 relating to the modified example shown in Figure 18, after the above-mentioned first deck installation process and second deck installation process, i.e., after installing the first precast deck 2A and the second precast deck 2B at the predetermined installation positions P1 and P2, respectively, the upper reinforcing bars 27A and the lower reinforcing bars 27B may be arranged, and finally filler material may be poured into the joint space S1.

[0089] FIG. 19 is a diagram illustrating a deck slab joint structure 1 according to another modification. Similar to FIG. 18, FIG. 19 also shows the deck slab joint structure 1 according to the modification as viewed from the front. In the deck slab joint structure 1 shown in FIG. 19, the upper and lower joint reinforcing bars in each precast deck slab 2A, 2B are arranged in a staggered pattern rather than the above-described vertically aligned arrangement. Specifically, the first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A in the first precast deck slab 2A are arranged in a staggered pattern (zigzag) along the deck slab width direction (direction perpendicular to the bridge axis). Similarly, the second upper joint reinforcing bar 22B and the second lower joint reinforcing bar 23B in the second precast deck slab 2B are arranged in a staggered pattern (zigzag) along the deck slab width direction (direction perpendicular to the bridge axis). In FIG. 19, for convenience, the first upper joint reinforcing bar 22A and the first lower joint reinforcing bar 23A, which are the joint reinforcing bars on the first precast floor slab 2A side, are shown hatched.

[0090] In addition, in this modified example, in the joint space S1 (joint portion 5), the first upper joint reinforcing bar 22A and the second lower joint reinforcing bar 23B are arranged side by side, and the second upper joint reinforcing bar 22B and the first lower joint reinforcing bar 23A are arranged side by side. In the deck slab joint structure 1 according to the above modified example, in a plan view, the first upper joint reinforcing bar 22A and the second upper joint reinforcing bar 22B are arranged alternately in the joint orthogonal direction, and the first lower joint reinforcing bar 23A and the second lower joint reinforcing bar 23B are arranged alternately in the joint orthogonal direction. Such examples of reinforcement arrangement can also be cited as variations of the deck slab joint structure 1.

[0091] Here, when the modified example described in FIG. 19 is adopted, the second precast floor slab 2B may be hung down from above and installed at the installation position P2 as shown in FIG. 7(B). In some cases, the joint reinforcing bars of the precast floor slab 2A and the second precast floor slab 2B may interfere with each other. Therefore, as a construction procedure corresponding to the modified example shown in FIG. 19, the second precast floor slab 2B may be installed using a horizontal insertion method as shown in FIG. 20. That is, in the embodiment shown in FIG. 20, the second precast floor slab 2B may be installed at installation position P2 by horizontally moving the second precast floor slab 2B in the direction of the arrow in the figure ((B) in the figure) from a state in which the second joint end surface 21B faces the first joint end surface 21A of the first precast floor slab 2A installed at installation position P1 and the second precast floor slab 2B is spaced apart from the first precast floor slab 2A relative to the normal installation position P2 ((A) in the figure). This makes it easier to install the second precast floor slab 2B at installation position P2 without interfering with the joint reinforcing bars of the first precast floor slab 2A and the second precast floor slab 2B.

[0092] The above describes embodiments of the present invention, but these are merely examples, and the present invention is not limited to these. Various modifications based on the knowledge of those skilled in the art are possible as long as they do not deviate from the spirit of the claims. [Explanation of symbols]

[0093] 1. Deck joint structure 2. Precast deck 3. Fixing body 4. Fiber-reinforced filler 5. Joint S1... Joint space 2A···First precast deck 2B: Second precast deck 21A...1st joint end surface 21B...Second joint end surface 22A···First upper joint rebar 22B···Second upper joint reinforcing bar 23A···First lower joint rebar 23B... Second lower joint reinforcing bar 27A···Upper reinforcement bar 27B Lower reinforcement

Claims

1. A deck joint structure in which a filler material is filled into a joint space formed by installing the joint end surfaces of a first precast deck and a second precast deck made of concrete at an interval, a first upper joint reinforcing bar and a first lower joint reinforcing bar that protrude from the first joint end surface of the first precast floor slab toward the joint space and have anchors formed on their tip sides, and are arranged in a direction perpendicular to the joint; second upper joint reinforcing bars and second lower joint reinforcing bars that protrude from the second joint end surface of the second precast floor slab toward the joint space and have anchors formed on their tip sides, and are arranged in multiple rows in a direction perpendicular to the joint; In the joint space, an upper reinforcing bar is arranged along the first upper joint reinforcing bar and the second upper joint reinforcing bar in a direction perpendicular to the joint; A lower reinforcing bar is arranged in the joint space along the first lower joint reinforcing bar and the second lower joint reinforcing bar in a direction perpendicular to the joint, Equipped with The first upper joint reinforcing bar and the second upper joint reinforcing bar, and the first lower joint reinforcing bar and the second lower joint reinforcing bar are respectively joined by an open lap joint. Deck joint structure.

2. 2. A deck joint structure as described in claim 1, wherein the upper reinforcing bars are arranged above the first upper joint reinforcing bars and the second upper joint reinforcing bars, and the lower reinforcing bars are arranged below the first lower joint reinforcing bars and the second lower joint reinforcing bars.

3. In a plan view, the first upper joint reinforcing bars and the second upper joint reinforcing bars are alternately arranged in a direction perpendicular to the joint, and the first lower joint reinforcing bars and the second lower joint reinforcing bars are alternately arranged in a direction perpendicular to the joint. The deck joint structure according to claim 1 or 2.

4. The first upper joint reinforcing bar and the first lower joint reinforcing bar are arranged vertically side by side, and the second upper joint reinforcing bar and the second lower joint reinforcing bar are arranged vertically side by side. The deck joint structure according to claim 3.

5. The first upper joint reinforcing bar and the second upper joint reinforcing bar are arranged at the same height, and the first lower joint reinforcing bar and the second lower joint reinforcing bar are arranged at the same height. The deck joint structure according to claim 1 or 2.

6. The first upper joint reinforcing bar, the second upper joint reinforcing bar, the first lower joint reinforcing bar, and the second lower joint reinforcing bar are When a tensile force acts on them, the average cross-sectional area of ​​the compression strut region where compression struts are formed between the anchors provided on the first upper joint reinforcing bar and the second upper joint reinforcing bar adjacent to each other in the direction perpendicular to the joint, and between the anchors provided on the first lower joint reinforcing bar and the second lower joint reinforcing bar adjacent to each other in the direction perpendicular to the joint, is 560 mm. ３ / mm or more, The deck joint structure according to claim 1 or 2.

7. A slab joint method for connecting a first precast slab and a second precast slab made of concrete, A first precast floor slab is provided with a plurality of first upper joint reinforcing bars and first lower joint reinforcing bars each having an anchoring body formed at the tip end thereof and arranged perpendicular to the joint. a first deck installation step of installing the deck at a position; a second floor slab installation process in which a second precast floor slab, in which a plurality of second upper joint reinforcing bars and second lower joint reinforcing bars protruding from a second joint end surface and having anchors formed on their tip ends are arranged in a direction perpendicular to the joint, is installed at a distance from the first precast floor slab so that a joint space is formed between the first joint end surface and the second joint end surface; a step of filling the joint space with filler material in a state in which the upper reinforcing bars are arranged so as to be along the first upper joint reinforcing bars and the second upper joint reinforcing bars, and the lower reinforcing bars are arranged so as to be along the first lower joint reinforcing bars and the second lower joint reinforcing bars, along the joint orthogonal direction in the joint space; Equipped with The first upper joint reinforcing bar and the second upper joint reinforcing bar, and the first lower joint reinforcing bar and the second lower joint reinforcing bar are respectively joined by an open lap joint. Deck joint method.

8. a lower reinforcing bar arrangement process in which, prior to at least the second deck installation process, lower reinforcing bars are arranged in advance along a direction perpendicular to the joints so as to be along the lower sides of the plurality of first lower joint reinforcing bars; After the second deck installation process, an upper reinforcing bar arrangement process is performed in which upper reinforcing bars are arranged along a direction perpendicular to the joints so as to be along the upper sides of the first upper joint reinforcing bars and the second upper joint reinforcing bars; Further provided with In the second floor slab installation step, the second precast floor slab is installed so that the lower reinforcing bars are attached to the lower sides of the plurality of second lower joint reinforcing bars. The deck slab joint method according to claim 7.

9. 9. The deck joint method according to claim 8, wherein the lower reinforcing bars are arranged in advance in the first lower joint reinforcing bars before the first precast deck is installed in a predetermined position.

10. The first upper joint reinforcing bar and the first lower joint reinforcing bar are arranged vertically side by side, and the second upper joint reinforcing bar and the second lower joint reinforcing bar are arranged vertically side by side, In the second floor slab installation step, the second precast floor slab is installed so that the second lower joint reinforcing bars are inserted from above into the gaps between the first upper joint reinforcing bars adjacent to each other in the joint orthogonal direction. A deck slab joint method according to any one of claims 7 to 9.

11. At the completion of the second deck installation process, the second upper joint reinforcing bar is placed at the same height as the first upper joint reinforcing bar, and the second lower joint reinforcing bar is placed at the same height as the first lower joint reinforcing bar. A deck slab joint method according to any one of claims 7 to 9.

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