Precast beam-column joint structure

Abstract

To facilitate horizontal positioning of a precast beam with respect to a precast column.SOLUTION: A precast column-beam joint structure includes: a precast column 10 that has a plurality of column main reinforcements 12 protruded from an outer peripheral part of a column top surface 10U; a pair of full-precast beams 20 and a pair of half-precast beams 40, in which each of beam ends 20E and 40E is loaded on the outer peripheral part of the column top surface 10U and in which insertion holes 34 and 54 subjected to vertical insertion of the column main reinforcements 12 are formed at the beam ends 20E and 40E; and cast-in-place concrete 16 that is placed in a space 14 surrounded by the beam ends 20E and 40E of the pair of full-precast beams 20 and the pair of half-precast beams 40.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a precast beam-column joint structure. [Background technology]

[0002] A known column-beam joint structure between a precast column and a pair of precast beams is one in which a split column-beam joint that divides the column-beam joint of the precast column into left and right halves is integrated into each end of the pair of precast beams (see, for example, Patent Document 1).

[0003] As a column-beam joint structure for reinforced concrete construction, a column-beam joint structure is known in which the main beam reinforcements of a pair of beams arranged on both sides of a column are fixed to the column-beam joint portion of a column made of fiber-reinforced concrete (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-229855 A [Patent Document 2] JP 2008-031699 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the joint structure between a precast column and a precast beam, for example, the beam ends of multiple precast beams are placed on the outer periphery of the top surface of the precast column, and concrete is poured into the space surrounded by these beam ends to join the precast column and multiple precast beams.

[0006] However, in the above case, it is difficult to horizontally position the precast beam relative to the precast column, which may reduce workability.

[0007] SUMMARY OF THE PRESENT EMBODIMENT In consideration of the above, an object of the present invention is to facilitate horizontal positioning of a precast beam relative to a precast column. [Means for solving the problem]

[0008] According to the first aspect The precast beam-column joint structure comprises a precast column having a plurality of column main reinforcements protruding from the outer periphery of the top surface of the column, a plurality of precast beams, each of whose beam end portions is placed on the outer periphery of the top surface of the column and in which insertion holes are formed through which the column main reinforcements are inserted in the vertical direction, and concrete poured into a space surrounded by the beam end portions of the plurality of precast beams.

[0009] First aspect According to the precast beam-column joint structure, the plurality of column main reinforcements protrude from the outer periphery of the upper surface of the precast column. The beam ends of the plurality of precast beams are placed on the outer periphery of the upper surface of the column.

[0010] Here, an insertion hole is formed in each of the beam ends. By inserting the column main reinforcement bars vertically into these insertion holes, the precast beams are positioned horizontally relative to the precast column. In this state, concrete is poured into the space surrounded by the beam ends, and the precast column and the beam ends are joined via the concrete.

[0011] In this way, in the present invention, the main reinforcement bars protruding from the outer periphery of the top surface of the precast column are inserted vertically into the insertion holes formed at the beam ends of the precast beams, making it easy to position the precast beams horizontally relative to the precast columns, thus improving the workability of the precast beams.

[0012] According to the second aspect Precast column-beam joint structure: According to the first aspect In a precast beam-column joint structure, adjacent beam ends have joint surfaces that are in contact with each other or face each other.

[0013] Second aspect According to the precast beam-column joint structure, adjacent beam ends each have a joint surface. By bringing these joint surfaces into contact with each other or facing each other and filling the gap with a joint material or the like, the gap between the adjacent beam ends can be easily sealed.

[0014] Therefore, formwork for sealing the gaps between adjacent beam ends can be omitted, improving workability.

[0015] According to the third aspect Precast column-beam joint structure: First aspect or According to the second aspect In a precast beam-column joint structure, the precast beam has a main beam bar that protrudes from the end face of the beam end and has an anchor at its tip, and is embedded in the concrete, and the concrete is fiber-reinforced concrete.

[0016] Third aspect According to the precast beam-column joint structure, the precast beam has a beam main bar. The beam main bar protrudes from the end face of the beam end and has an anchor at the tip. By embedding the beam main bar in concrete, the precast beam and the precast column are joined via the concrete.

[0017] Here, the concrete is fiber-reinforced concrete. As described above, an anchor is provided at the tip of the beam main reinforcement. By embedding this anchor in the fiber-reinforced concrete, the joint strength between the beam main reinforcement and the fiber-reinforced concrete is increased. This makes it possible to omit, for example, a mechanical joint that connects the beam main reinforcement of opposing precast beams. Therefore, workability is improved. Effect of the Invention

[0018] As described above, according to the present invention, it is possible to easily position a precast beam relative to a precast column in the horizontal direction. [Brief description of the drawings]

[0019] [Figure 1] This is a plan view showing a pair of full precast beams and a pair of half precast beams to which the precast beam column joint structure of the first embodiment is applied. [Diagram 2] 2 is a cross-sectional view taken along line 2-2 of FIG. 1. [Diagram 3] 3 is a cross-sectional view taken along line 3-3 in FIG. 1. [Figure 4] FIG. 2 is a plan view showing the full precast beam shown in FIG. 1. [Diagram 5] FIG. 2 is a plan view showing the half precast beam shown in FIG. 1. [Figure 6] 6 is a cross-sectional view corresponding to the cross section along line 6-6 in FIG. 2. [Figure 7] 1A and 1B are elevation views illustrating a construction method for a precast beam-column joint structure according to a first embodiment. [Figure 8] This is a plan view showing a pair of full precast beams and a pair of half precast beams to which a precast column-beam joint structure in accordance with the second embodiment is applied. [Figure 9] 9 is a cross-sectional view taken along line 9-9 in FIG. 8. [Figure 10] 10 is a cross-sectional view taken along line 10-10 in FIG. 8. [Figure 11] 11 is a cross-sectional view taken along line 11-11 of FIG. 9. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First embodiment First, the first embodiment will be described.

[0021] (Precast beam-column joint structure) As shown in Figures 1, 2, and 3, the precast beam-column joint structure according to this embodiment includes a precast column 10 (see Figure 2), a pair of full precast beams 20, and a pair of half precast beams 40. The full precast beam 20 and the half precast beam 40 are examples of precast beams.

[0022] (Precast columns) As shown in Figures 2 and 3, the precast column 10 is made of precast concrete. The cross-sectional shape of the precast column 10 is rectangular. A plurality of column main reinforcements 12 are embedded in the outer periphery of the precast column 10. The cross-sectional shape of the precast column 10 can be changed as appropriate.

[0023] The multiple column main reinforcements 12 are arranged along the material axis direction of the precast column 10. The multiple column main reinforcements 12 are also arranged at intervals in the circumferential direction of the precast column 10. The upper ends of these column main reinforcements 12 protrude upward from the outer periphery of the column upper surface 10U of the precast column 10. The column upper surface 10U of the precast column 10 is formed in a rectangular shape in a plan view.

[0024] (Full precast beams) As shown in Fig. 2, the full precast beam 20 is formed of precast concrete. The cross-sectional shape of the full precast beam 20 is rectangular. A plurality of lower end beam main bars 22, a plurality of upper end beam main bars 24, and a plurality of shear reinforcement bars 26 are embedded in this full precast beam 20. The lower end beam main bars 22 and the upper end beam main bars 24 are examples of beam main bars.

[0025] The multiple lower end beam main reinforcements 22 and upper end beam main reinforcements 24 are embedded along the material axis direction of the full precast beam 20. The multiple lower end beam main reinforcements 22 are embedded on the lower end side of the full precast beam 20. The multiple lower end beam main reinforcements 22 are also arranged at intervals in the width direction of the full precast beam 20. One end side of these lower end beam main reinforcements 22 protrudes from the end face 20A of the full precast beam 20.

[0026] The multiple upper end beam main reinforcements 24 are embedded in the upper end side of the full precast beam 20. The multiple upper end beam main reinforcements 24 are also arranged at intervals in the width direction of the full precast beam 20. One end side of these upper end beam main reinforcements 24 protrudes from the end face 20A of the full precast beam 20.

[0027] An anchor 28 is provided at one end (tip) of each of the lower end beam main reinforcement 22 and the upper end beam main reinforcement 24. The anchor 28 is, for example, a mechanically fixed anchor such as a plate nut, and is embedded in the cast-in-place concrete 16 described later.

[0028] As shown in Fig. 4, a notch 30 is formed in the beam end 20E of the full precast beam 20. The notch 30 is cut out in a rectangular shape in plan view at one end side in the width direction (arrow W direction) of the beam end 20E. This notch 30 creates a step in the end face 20A of the beam end 20E in plan view. In other words, at one end side in the width direction of the beam end 20E, the bottom face of the notch 30 is the end face 20A.

[0029] In addition, in the notch 30, as shown by the two-dot chain line, the column main reinforcement 12 protruding from the outer periphery of the column top surface 10U of the precast column 10 is placed, and the notch 30 is filled with cast-in-place concrete 16 (see Figure 6) described later.

[0030] The other end in the width direction of the beam end 20E is placed on the outer periphery of the column upper surface 10U of the precast column 10. A protrusion 32 is provided on the side surface 20S on the other end side in the width direction (arrow W direction) of the beam end 20E. The protrusion 32 is formed integrally with the full precast beam 20 by precast concrete. The protrusion 32 protrudes from the side surface 20S of the beam end 20E and is placed on the outer periphery of the column upper surface 10U.

[0031] The protruding portion 32 is formed in a rectangular shape in a plan view, and is arranged along a corner of the column upper surface 10U. The protruding portion 32 is formed from the lower end to the upper end of the beam end portion 20E. The tip surface of the protruding portion 32 in the protruding direction is a joint surface 32A that is joined to an end surface 40A of a half precast beam 40 described later.

[0032] The beam end 20E and the protrusion 32 placed on the outer periphery of the column upper surface 10U are made of fiber-reinforced concrete, and form a beam-column joint together with cast-in-place concrete 16 (see FIG. 6), which will be described later. Meanwhile, the portion of the full precast beam 20 other than the beam end 20E and the protrusion 32 (hereinafter referred to as the "beam body") 20M is made of ordinary concrete.

[0033] A plurality of insertion holes 34 (in this embodiment) are formed in the beam end 20E and the protruding portion 32. The plurality of insertion holes 34 penetrate the beam end 20E and the protruding portion 32 in the vertical direction. Each insertion hole 34 is formed by embedding a sheath tube (cylindrical tube) in the beam end 20E and the protruding portion 32.

[0034] With the beam end 20E and the protruding portion 32 placed on the outer periphery of the column upper surface 10U, the column main reinforcements 12 protruding from the column upper surface 10U are inserted (penetrated) in the vertical direction into each insertion hole 34. With the column main reinforcements 12 inserted, each insertion hole 34 is filled with a filler material (not shown) such as grout. As a result, the beam end 20E and the protruding portion 32 are fixed to the precast column 10 via the multiple column main reinforcements 12.

[0035] (Half precast beam) As shown in Fig. 3, the half-precast beam 40 is formed of half-precast concrete. This half-precast beam 40 forms a beam 60 together with top concrete 58 poured thereon. The cross-sectional shape of the beam 60 (half-precast beam 40) is rectangular. A plurality of lower end beam main bars 42, a plurality of upper end beam main bars 44, and a plurality of shear reinforcement bars 46 are embedded in this beam 60. The lower end beam main bars 42 and the upper end beam main bars 44 are examples of beam main bars.

[0036] The multiple lower end beam main bars 42 and upper end beam main bars 44 are arranged along the material axis direction of the beam 60. The multiple lower end beam main bars 42 are embedded in the lower end side of the beam 60, i.e., the lower end side of the half precast beam 40. These lower end beam main bars 42 are arranged at intervals in the width direction of the half precast beam 40. One end side of each lower end beam main bar 42 protrudes from the end face 40A of the half precast beam 40.

[0037] The multiple upper end beam main reinforcements 44 are embedded in the upper end side of the beam 60, i.e., in the top concrete 58. The multiple upper end beam main reinforcements 44 are also arranged on the upper surface 40U of the half precast beam 40 at intervals in the width direction of the half precast beam 40. These upper end beam main reinforcements 44 are held by multiple shear reinforcements 46 protruding from the upper surface 40U of the half precast beam 40.

[0038] 5, one end of the upper end beam main reinforcement 44 protrudes from the end face 40A of the half precast beam 40 in a plan view. Here, the upper end beam main reinforcement 44 has two beam main reinforcements 44A, 44B and a mechanical joint 44C that connects the two beam main reinforcements 44A, 44B.

[0039] The mechanical joint 44C is arranged so as not to protrude from the end surface 40A of the half precast beam 40 in plan view. The beam main reinforcement bars 44A and 44B are connected to the mechanical joint 44C. The beam main reinforcement bars 44B protrude from the end surface 40A of the half precast beam 40 in plan view.

[0040] An anchor 48 is provided at one end (tip) of each of the lower end beam main reinforcement 42 and the upper end beam main reinforcement 44. The anchor 48 is, for example, a mechanically fixed anchor such as a plate nut, and is embedded in the cast-in-place concrete 16 (see FIG. 6) described later.

[0041] 5, a notch 50 is formed on one end side in the width direction (arrow W direction) of the beam end portion 40E of the half precast beam 40. Therefore, at one end side in the width direction of the beam end portion 40E, the bottom surface of the notch 50 is the end surface 40A.

[0042] A protruding portion 52 is provided on the side surface 40S on the other end side in the width direction of the beam end portion 40E. A plurality of insertion holes 54 are formed in the beam end portion 40E and the protruding portion 52. The tip surface of the protruding portion 52 in the protruding direction is made to be a joint surface 52A.

[0043] Furthermore, the configuration of the notch 50 and the protrusion 52 is similar to that of the notch 30 and the protrusion 32 of the full precast beam 20.

[0044] The beam end 40E and the protruding portion 52 of the half precast beam 40 are made of fiber-reinforced concrete. Furthermore, the top concrete 58 (see FIG. 3) poured on the beam end 40E and the protruding portion 52 is made of fiber-reinforced concrete. Meanwhile, the portion of the half precast beam 40 other than the beam end 40E (hereinafter referred to as the "beam main body portion") 40M is made of ordinary concrete. Furthermore, the top concrete 58 (see FIG. 3) poured on the beam main body portion 40M is made of ordinary concrete.

[0045] (Column and beam joint section) 1, a pair of full precast beams 20 are arranged with their end faces 20A facing each other. The pair of full precast beams 20 are also arranged with their lower end beam main reinforcements 22 facing each other (closely facing each other) and their upper end beam main reinforcements 24 facing each other (closely facing each other).

[0046] Similarly, the pair of half precast beams 40 are arranged with their end faces 40A facing each other. The pair of half precast beams 40 are also arranged with their lower end beam main reinforcements 42 facing each other (closely facing each other) and their upper end beam main reinforcements 44 facing each other (closely facing each other).

[0047] A pair of full precast beams 20 and a pair of half precast beams 40 are arranged in a mutually intersecting state. Then, as shown in Fig. 6, cast-in-place concrete 16 is poured into the space 14 surrounded by the beam ends 20E, 40E and the protruding parts 32, 52 of the full precast beam 20 and the half precast beam 40. In addition, top concrete 58 (see Fig. 3) is poured onto the beam end 40E and the protruding part 52 of the half precast beam 40. This forms a beam-column connection.

[0048] The cast-in-place concrete 16 is fiber-reinforced concrete. The fiber-reinforced concrete in this embodiment is concrete containing, for example, steel fiber, glass fiber, carbon fiber, organic fiber, etc. The cast-in-place concrete 16 is an example of concrete.

[0049] Here, a part of the protrusion 32 of the full precast beam 20 is placed in the notch 50 of the adjacent half precast beam 40. As a result, the joint surface 32A of the protrusion 32 and the end surface 40A of the notch 50 face each other (closely facing each other). The gap between the joint surface 32A of the protrusion 32 and the end surface 40A of the notch 50 is closed by a joint material (not shown) such as mortar or a backup material. This prevents the poured-in-place concrete 16 from leaking from the gap between the joint surface 32A of the protrusion 32 and the end surface 40A of the notch 50. The end surface 40A of the notch 50 is an example of a joint surface.

[0050] Similarly, a portion of the protrusion 52 of the half precast beam 40 is disposed in the notch 30 of the adjacent full precast beam 20. This causes the joint surface 52A of the protrusion 52 to face (closely face) the end surface 20A of the notch 30. The gap between the joint surface 52A of the protrusion 52 and the end surface 20A of the notch 30 is closed by a joint material. This prevents the poured-in-place concrete 16 from leaking from the gap between the joint surface 52A of the protrusion 52 and the end surface 20A of the notch 30. The end surface 20A of the notch 30 is an example of a joint surface.

[0051] (Construction method for precast beam-column joint structure) Next, an example of a construction method for a precast beam-column joint structure will be described.

[0052] Fig. 7(A) shows a precast column 10 after construction. From this state, a pair of half precast beams 40 are successively lifted by a crane or the like (not shown), and as shown in Fig. 7(B), the beam ends 40E and the protruding parts 52 of the pair of half precast beams 40 are placed on the outer periphery of the column upper surface 10U from above the precast column 10. This positions the half precast beams 40 in the vertical direction relative to the precast column 10.

[0053] At this time, the multiple column main reinforcements 12 protruding from the column upper surface 10U are inserted in the vertical direction into the multiple insertion holes 54 (see FIG. 3) formed in the beam ends 40E and the protruding parts 52 of the pair of half precast beams 40. This allows the pair of half precast beams 40 to be positioned horizontally with respect to the column upper surface 10U of the precast column 10.

[0054] In addition, the mechanical joints 44C of each upper end main beam reinforcement 44 of the half precast beam 40 are not connected to the main beam reinforcement 44B.

[0055] Next, the pair of full precast beams 20 are lifted in sequence by a crane (not shown), and the beam ends 20E and the protruding parts 32 of the pair of full precast beams 20 are placed on the outer periphery of the column upper surface 10U from above the precast column 10. This positions the pair of full precast beams 20 in the vertical direction relative to the column upper surface 10U of the precast column 10.

[0056] At this time, the multiple column main reinforcements 12 protruding from the column upper surface 10U are inserted into the multiple insertion holes 34 (see FIG. 4) formed in the beam ends 40E and the protruding portions 32 of the pair of half precast beams 40. This allows the pair of half precast beams 40 to be positioned horizontally with respect to the column upper surfaces 10U of the precast columns 10.

[0057] Here, as described above, the beam main reinforcement 44B is not connected to the mechanical joint 44C of each upper end beam main reinforcement 44 of the half precast beam 40. Therefore, the lower end beam main reinforcement 22 of the full precast beam 20 is prevented from interfering with the upper end beam main reinforcement 44 (beam main reinforcement 44B) of the half precast beam 40.

[0058] 1, a portion of the protrusion 32 of the full precast beam 20 is placed in the notch 50 of the adjacent half precast beam 40. Similarly, a portion of the protrusion 52 of the half precast beam 40 is placed in the notch 30 of the adjacent full precast beam 20. This causes the joint surface 52A of the protrusion 52 to face the end surface 20A of the notch 30. In this state, the gap between the joint surface 52A of the protrusion 52 and the end surface 20A of the notch 30 is closed by a joint material.

[0059] Next, filler is filled into each of the insertion holes 34, 54 of the pair of full precast beams 20 and the pair of half precast beams 40. Also, as shown in Fig. 7(B), beam main bars 44B are connected to the mechanical joints 44C of each upper end beam main bar 44 of the half precast beams 40.

[0060] Next, a formwork (not shown) is temporarily set up on the half precast beam 40. Next, as shown in Fig. 6, cast-in-place concrete (fiber reinforced concrete) 16 is poured into the space 14 surrounded by the beam ends 20E, 40E and protruding portions 32, 52 of the pair of full precast beams 20 and the pair of half precast beams 40, and top concrete (fiber reinforced concrete) 58 (see Fig. 3) is poured onto the beam end 40E and protruding portion 52 of the half precast beam 40. This forms a beam-column connection.

[0061] 3, top concrete (ordinary concrete) 58 is poured on top of the beam body 40M of the pair of half precast beams 40 to form a beam 60. At the boundary between the beam body 40M and the beam end 40E of the half precast beam 40, a partition plate such as lath is installed to separate the cast-in-place concrete 16 (see FIG. 6) from the top concrete 58 (ordinary concrete).

[0062] The order of the above-mentioned construction steps (procedures) may be changed as appropriate depending on the situation.

[0063] (effect) Next, the effects of the first embodiment will be described.

[0064] As described above, in this embodiment, when the half precast beam 40 is placed on the outer periphery of the column top surface 10U of the precast column 10, the multiple column main reinforcements 12 protruding from the column top surface 10U are inserted in the vertical direction into the insertion holes 54 formed in the beam end portion 40E and the protruding portion 52 of the half precast beam 40. This positions the half precast beam 40 in the vertical and horizontal directions relative to the column top surface of the precast column 10.

[0065] Similarly, when placing the full precast beam 20 on the column upper surface 10U of the precast column 10, the multiple column main reinforcements 12 protruding from the column upper surface 10U are inserted in the vertical direction into the multiple insertion holes 34 formed in the beam end 20E and the protruding portion 32 of the full precast beam 20. This positions the full precast beam 20 in the vertical and horizontal directions relative to the column upper surface 10U of the precast column 10.

[0066] In this manner, in this embodiment, the full precast beam 20 and the half precast beam 40 can be easily positioned in the horizontal direction relative to the precast column 10. Therefore, the workability of the full precast beam 20 and the half precast beam 40 is improved.

[0067] In addition, by placing the beam ends 20E, 40E and protrusions 32, 52 of the full precast beam 20 and the half precast beam 40 on the outer periphery of the column top surface 10U of the precast column 10, the area of ​​the cast-in-place concrete 16 can be reduced.

[0068] In this embodiment, after placing a pair of full precast beams 20 on the column upper surface 10U of the precast column 10, the beam main reinforcement 44B is connected to the mechanical joint 44C of the upper end beam main reinforcement 44 of the half precast beam 40. Therefore, when placing a pair of full precast beams 20 on the column upper surface 10U of the precast column 10, the lower end beam main reinforcement 22 is prevented from interfering with the upper end beam main reinforcement 44 (beam main reinforcement 44B) of the half precast beam 40. This further improves the workability of the full precast beam 20.

[0069] Furthermore, adjacent full precast beams 20 and half precast beams 40 are arranged with the joint surface 32A of the protrusion 32 facing the end surface 40A of the notch 50. The gap between the joint surface 32A of the protrusion 32 and the end surface 40A of the notch 50 is closed with a joint material. Similarly, adjacent full precast beams 20 and half precast beams 40 are arranged with the end surface 20A of the notch 30 facing the joint surface 52A of the protrusion 52. The gap between the end surface 20A of the notch 30 and the joint surface 52A of the protrusion 52 is closed with a joint material.

[0070] This prevents the poured concrete 16 from leaking from the gap between the adjacent beam ends 20E, 40E when pouring the poured concrete 16 into the space 14 surrounded by the beam ends 20E, 40E and the protrusions 32, 52 of the full precast beam 20 and the half precast beam 40. Therefore, in this embodiment, formwork or the like for closing the gap between the adjacent beam ends 20E, 40E can be omitted, improving workability.

[0071] Further, notches 30, 50 are formed in the beam ends 20E, 40E of the full precast beam 20 and the half precast beam 40, respectively. In the notches 30, 50, the column main reinforcements 12 protruding from the column upper surface 10U of the precast column 10 are placed.

[0072] By forming the notches 30, 50 in the beam ends 20E, 40E in this manner, the number of insertion holes 34, 54 formed in the beam ends 20E, 40E is reduced. Therefore, for example, the number of sheath tubes for forming the insertion holes in the beam ends 20E, 40E is reduced, thereby reducing costs.

[0073] Furthermore, in this embodiment, the planar shapes of the beam ends 20E, 40E of the full precast beam 20 and the half precast beam 40 can be made the same. Therefore, the productivity of the full precast beam 20 and the half precast beam 40 is improved.

[0074] Furthermore, anchors 28, 48 are provided at the tips of the lower end beam main bars 22, 42 and the upper end beam main bars 24, 44 of the full precast beam 20 and the half precast beam 40, respectively, to be embedded in the cast-in-place concrete 16. The cast-in-place concrete 16 is made of fiber-reinforced concrete. This increases the joint strength between the lower end beam main bars 22, 42 and the upper end beam main bars 24, 44 and the cast-in-place concrete 16.

[0075] Therefore, in this embodiment, it is possible to omit the mechanical joints connecting the lower end beam main reinforcements 22 of a pair of full precast beams 20 and the mechanical joints connecting the upper end beam main reinforcements 24 of the pair of full precast beams 20. Similarly, it is possible to omit the mechanical joints connecting the lower end beam main reinforcements 42 of a pair of half precast beams 40 and the mechanical joints connecting the upper end beam main reinforcements 44 of the pair of half precast beams 40. Therefore, workability is improved.

[0076] Furthermore, the beam ends 20E, 40E and the protrusions 32, 52 of the full precast beam 20 and the half precast beam 40 are formed of fiber-reinforced concrete. That is, in this embodiment, the column-beam joint is formed of fiber-reinforced concrete. This increases the splitting strength of the column-beam joint, making it possible to omit shear reinforcement bars and the like embedded in the column-beam joint. This simplifies the structure of the column-beam joint.

[0077] Second Embodiment Next, a second embodiment will be described. In the second embodiment, the same reference numerals will be used to designate the same members as in the first embodiment, and the description thereof will be omitted as appropriate.

[0078] (Precast beam-column joint structure) As shown in Figures 8, 9, and 10, the precast column beam joint structure of the second embodiment comprises a precast column 10 (see Figure 9), a pair of full precast beams 20, and a pair of half precast beams 40.

[0079] (Full precast beams) As shown in Fig. 8, the beam end 20E of the full precast beam 20 is placed on the outer periphery of the column upper surface 10U (see Fig. 10) of the precast column 10. This beam end 20E is provided with a pair of protrusions 32. The pair of protrusions 32 are formed integrally with the beam end 20E of the full precast beam 20 by precast concrete. The pair of protrusions 32 protrude from both side surfaces 20S of the beam end 20E, respectively, and are placed on the outer periphery of the column upper surface 10U.

[0080] The pair of protrusions 32 are formed in a rectangular shape in a plan view and are arranged along the corners of the column upper surface 10U. The pair of protrusions 32 are provided from the lower end to the upper end of the beam end 20E. The pair of protrusions 32 each have an insertion hole 34 formed therein.

[0081] The pair of protrusions 32 have joint surfaces 32A that are joined to the side surfaces 40S of the beam end 40E of the half precast beam 40. The joint surfaces 32A are flush with the end surface 20A of the beam end 20E. The joint surfaces 32A are not limited to being flush with the end surface 20A of the beam end 20E, and there may be a step between them.

[0082] (Half precast beam) The beam end 40E of the half precast beam 40 is placed on the outer periphery of the column upper surface 10U of the precast column 10. A plurality of insertion holes 54 are formed in this beam end 40E. A plurality of column main reinforcements 12 protruding from the column upper surface 10U are inserted in the vertical direction into the plurality of insertion holes 54. Note that the beam end 40E of the half precast beam 40 in the second embodiment is not provided with a notch 50 and a protruding portion 52 (see FIG. 5).

[0083] (Column and beam joint section) As shown in Fig. 9, a pair of full precast beams 20 are arranged with their end faces 20A facing each other and with the joint faces 32A (see Fig. 8) of their protrusions 32 facing each other. Also, a pair of full precast beams 20 are arranged with their lower end beam main reinforcements 22 facing each other and their upper end beam main reinforcements 24 facing each other.

[0084] As shown in Fig. 10, the pair of half precast beams 40 are arranged with their end faces 40A facing each other. The pair of half precast beams 40 are also arranged with their lower end beam main reinforcements 42 facing each other and their upper end beam main reinforcements 44 facing each other.

[0085] As shown in Fig. 8, a pair of full precast beams 20 and a pair of half precast beams 40 are arranged in a mutually intersecting state. In this case, the beam end portion 40E of the half precast beam 40 is arranged between the protruding portions 32 of the opposing pair of full precast beams 20. In other words, the protruding portions 32 of the pair of full precast beams 20 are arranged on both sides of the beam end portion 40E of the half precast beam 40.

[0086] 11, in-situ concrete 72 is poured into the space 70 surrounded by the beam end 40E and the protruding portion 32 of the full precast beam 20 and the half precast beam 40. This forms a beam-column joint. The space 70 is formed in a rectangular shape in a plan view.

[0087] Here, the joint surface 32A of the protruding portion 32 of the full precast beam 20 faces (closely faces) the side surface 40S of the half precast beam 40. The gap between the joint surface 32A of the protruding portion 32 and the side surface 40S of the half precast beam 40 is closed by a joint material (not shown). This prevents the poured-in-place concrete 72 from leaking from the gap between the joint surface 32A of the protruding portion 32 and the side surface 40S of the half precast beam 40. The side surface 40S of the half precast beam 40 is an example of a joint surface.

[0088] (Construction method for precast beam-column joint structure) Next, an example of a construction method for a precast beam-column joint structure will be described.

[0089] First, the beam end portions 40E of the pair of half precast beams 40 are placed on the outer periphery of the column upper surface 10U of the precast column 10. This positions the pair of full precast beams 20 in the vertical direction relative to the column upper surface 10U of the precast column 10.

[0090] At this time, the multiple column main reinforcements 12 protruding from the column upper surface 10U are inserted in the vertical direction into the multiple insertion holes 54 formed in the beam end portion 40E of each half precast beam 40. This allows the pair of half precast beams 40 to be positioned horizontally with respect to the column upper surface 10U of the precast column 10.

[0091] In addition, the mechanical joint 44C of the upper end main beam reinforcement 44 of the half precast beam 40 is not connected to the main beam reinforcement 44B.

[0092] Next, the beam end portions 20E and the pair of protruding portions 32 of the pair of full precast beams 20 are placed on the outer periphery of the column upper surface 10U of the precast column 10. This positions the pair of full precast beams 20 in the vertical direction with respect to the column upper surface 10U of the precast column 10.

[0093] At this time, the multiple column main reinforcements 12 protruding from the column upper surface 10U are inserted in the vertical direction into the multiple insertion holes 34 formed in the beam end portion 20E of the full precast beam 20 and the pair of protruding portions 32. This allows the pair of full precast beams 20 to be positioned horizontally with respect to the column upper surface 10U of the precast column 10.

[0094] Here, the beam main reinforcement 44B is not connected to the mechanical joint 44C of the upper end beam main reinforcement 44 of the half precast beam 40. Therefore, the lower end beam main reinforcement 22 of the full precast beam 20 is prevented from interfering with the upper end beam main reinforcement 44 (beam main reinforcement 44B) of the half precast beam 40.

[0095] 8, the protruding portions 32 of a pair of full precast beams 20 are arranged on both sides of the beam end portion 40E of each half precast beam 40. This causes the side surface 40S of the half precast beam 40 to face the joint surface 32A of the protruding portion 32. In this state, the gap between the side surface 40S of the half precast beam 40 and the joint surface 32A of the protruding portion 32 is closed by a joint material.

[0096] Next, a filler is filled into the insertion holes 34, 54 of the full precast beam 20 and the half precast beam 40. Also, the beam main reinforcement 44B is connected to the mechanical joint 44C of the upper end beam main reinforcement 44 of the half precast beam 40.

[0097] Next, a formwork (not shown) is temporarily set up on the half precast beam 40. Next, as shown in Fig. 11, cast-in-place concrete (fiber reinforced concrete) 72 is poured into the space 70 surrounded by the beam ends 20E, 40E and the protruding portion 32 of the full precast beam 20 and the half precast beam 40, and top concrete (fiber reinforced concrete) 58 (see Fig. 10) is poured onto the beam end 40E and the protruding portion 32 of the half precast beam 40. This forms a beam-column connection.

[0098] Moreover, top concrete (ordinary concrete) 58 (see FIG. 10) is poured onto the beam main body portions 40M of the pair of half precast beams 40 to form a beam 60.

[0099] The order of the above-mentioned construction steps (procedures) may be changed as appropriate depending on the situation.

[0100] (effect) Next, the effects of the second embodiment will be described.

[0101] As described above, in this embodiment, when the half precast beam 40 is placed on the column upper surface 10U of the precast column 10, the multiple column main reinforcements 12 protruding from the column upper surface 10U are inserted in the vertical direction into the insertion holes 54 formed in the beam end portion 40E of the half precast beam 40. This positions the half precast beam 40 in the vertical and horizontal directions relative to the column upper surface of the precast column 10.

[0102] Similarly, when placing the full precast beam 20 on the column upper surface 10U of the precast column 10, the multiple column main reinforcements 12 protruding from the column upper surface 10U are inserted in the vertical direction into the multiple insertion holes 34 formed in the beam end 20E of the full precast beam 20 and the pair of protruding parts 32. This positions the full precast beam 20 in the vertical and horizontal directions relative to the column upper surface 10U of the precast column 10.

[0103] In this manner, in this embodiment, the full precast beam 20 and the half precast beam 40 can be easily positioned in the horizontal direction relative to the precast column 10. Therefore, the workability of the full precast beam 20 and the half precast beam 40 is improved.

[0104] In this embodiment, as shown in Fig. 11, the space 70 surrounded by the beam ends 20E, 40E and the protruding portion 32 of the full precast beam 20 and the half precast beam 40 is rectangular in plan view. This makes it easier to fill the space 70 with cast-in-place concrete 72. This makes it easier to pour the cast-in-place concrete 72.

[0105] In addition, in this embodiment, the shape of the beam end portion 40E of the half precast beam 40 is simplified. Therefore, the productivity of the half precast beam 40 is improved.

[0106] In this embodiment, a pair of protrusions 32 is provided at the beam end 20E of the full precast beam 20. However, the pair of protrusions 32 may be provided at the beam end of the full precast beam 20, not at the half precast beam 40.

[0107] (Modification) Next, modified examples of the first embodiment and the second embodiment will be described. Note that, although various modified examples will be described below using the first embodiment as an example, these modified examples can also be appropriately applied to the second embodiment.

[0108] In the above first embodiment, the upper end main beam reinforcement 44 of the half precast beam 40 is disposed below the upper end main beam reinforcement 24 of the full precast beam 20. However, the upper end main beam reinforcement 44 of the half precast beam 40 may be disposed above the upper end main beam reinforcement 24 of the full precast beam 20. In this case, the main beam reinforcement 44B can be connected to the mechanical joint 44C of the half precast beam 40 above the upper end main beam reinforcement 24 of the full precast beam 20, improving workability.

[0109] In the first embodiment, the joint surface 32A of the protruding portion 32 of the full precast beam 20 faces the end surface 40A of the notch 50 of the half precast beam 40. However, the joint surface 32A of the protruding portion 32 and the end surface 40A of the notch 50 may be brought into contact (surface contact) with each other to close the gap between the joint surface 32A of the protruding portion 32 and the end surface 40A of the notch 50. Similarly, in the first embodiment, the joint surface 52A of the protruding portion 52 of the half precast beam 40 faces the end surface 20A of the notch 30 of the full precast beam 20. However, the joint surface 52A of the protruding portion 52 and the end surface 20A of the notch 30 may be brought into contact (surface contact) with each other to close the gap between the joint surface 52A of the protruding portion 52 and the end surface 20A of the notch 30.

[0110] In the first embodiment, a plurality of insertion holes 34, 54 are formed in the beam ends 20E, 40E of the full precast beam 20 and the half precast beam 40. However, at least one insertion hole 34, 54 can be formed in the beam ends 20E, 40E of the full precast beam 20 and the half precast beam 40.

[0111] In addition, in the first embodiment, the beam ends 20E, 40E of the full precast beam 20 and the half precast beam 40 are formed with protrusions 32, 52 that are rectangular in plan view, respectively. However, the shape and size of the protrusions 32, 52 can be changed as appropriate. Similarly, in the first embodiment, the beam ends 20E, 40E of the full precast beam 20 and the half precast beam 40 are formed with notches 30, 50 that are rectangular in plan view, respectively. However, the shape and size of the notches 30, 50 can be changed as appropriate.

[0112] It is possible to omit the protruding portions 32, 52 and the notches 30, 50. When the protruding portions 32, 52 and the notches 30, 50 are omitted, for example, the gap between the adjacent beam ends 20E, 40E is closed by a formwork or the like.

[0113] In addition, in the first embodiment, the cast-in-place concrete 16 is fiber-reinforced concrete. However, the cast-in-place concrete 16 may be ordinary concrete. Similarly, in the first embodiment, the beam ends 20E, 40E and the protruding parts 32, 52 of the full precast beam 20 and the half precast beam 40 are made of fiber-reinforced concrete. However, the beam ends 20E, 40E and the protruding parts 32, 52 of the full precast beam 20 and the half precast beam 40 may be made of ordinary concrete. In addition, the top concrete 58 poured on the beam end 40E and the protruding part 52 of the half precast beam 40 may also be made of ordinary concrete.

[0114] In the first embodiment, the lower end beam main reinforcements 22 and the upper end beam main reinforcements 24 of a pair of full precast beams 20 are not connected to each other. However, the lower end beam main reinforcements 22 and the upper end beam main reinforcements 24 of a pair of full precast beams 20 may be connected to each other by mechanical joints or lap joints. Similarly, the lower end beam main reinforcements 42 and the upper end beam main reinforcements 44 of a pair of half precast beams 40 may be connected to each other by mechanical joints or lap joints.

[0115] Furthermore, in the above first embodiment, the beam end portions 40E of a pair of full precast beams 20 and a pair of half precast beams 40 are placed on the column upper surface 10U of the precast column 10. However, the beam end portions of four full precast beams or the beam end portions of four half precast beams may be placed on the column upper surface 10U of the precast column 10. Note that the precast beam in the above first and second embodiments is a concept that includes full precast beams and half precast beams.

[0116] Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and one embodiment and various modified examples may be used in appropriate combination, and it is of course possible to implement the present invention in various forms without departing from the gist of the present invention. [Explanation of symbols]

[0117] 10 Precast columns 10U column top surface 12 Column main reinforcement 14 Space 16 Cast-in-place concrete (concrete) 20 Full precast beam (precast beam) 20A end face 20E Beam end 22 Lower end beam main reinforcement (beam main reinforcement) 24 Top end beam main reinforcement (beam main reinforcement) 28 Fixing body 32 Protrusion 32A Joint surface 34 Insertion hole 40 Half precast beam (precast beam) 40A End surface (joint surface) 40E beam end 40S side (joint surface) 42 Lower end beam main reinforcement (beam main reinforcement) 44 Top end beam main reinforcement (beam main reinforcement) 48 Fixing body 52 Protrusion 52A Joint surface 54 Insertion hole 70 space 72 Cast-in-place concrete

Claims

1. A precast column having a plurality of main reinforcements protruding from the outer periphery of the top surface of the column; A precast beam in which each beam end is placed on an outer periphery of the upper surface of the column and an insertion hole through which the column main reinforcement is inserted in the vertical direction is formed in the beam end; Concrete is poured into a space surrounded by the column top surface of the precast column and the beam ends of the plurality of precast beams; A precast column-beam joint structure.

2. The adjacent beam ends each have a joint surface that is in contact with or faces each other. The precast beam-column joint structure according to claim 1.

3. The precast beam has a protrusion protruding from a side surface of the beam end and placed on an outer periphery of the column upper surface, The insertion hole is formed in the protrusion. A precast beam-column joint structure according to claim 1 or 2.

4. A notch is formed on one end side of the beam end of the precast beam in the width direction, in which the protrusion of the adjacent precast beam is disposed. The precast beam-column joint structure according to claim 3.

5. The precast beam has a main beam reinforcement that protrudes from the end face of the beam end, has an anchor at the tip, and is embedded in the concrete, The concrete is fiber-reinforced concrete. A precast beam-column joint structure according to any one of claims 1 to 4.

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