JP7664754B2 - Beam-column joint structure - Google Patents

Description

The present invention relates to a column-beam joint structure.

Patent Document 1 discloses technology related to a precast column-beam member joint structure. In this prior art, the precast column-beam member joint structure comprises a lower precast column member and a pair of precast beam members that have split column-beam joint sections at their ends, which divide the column-beam joint section of the lower precast column member into left and right sections, and each split column-beam joint section is placed on the lower precast column member.

Patent Document 2 discloses a method for constructing a joint structure and a technology related to the joint structure. In this prior art, a perforated steel plate dowel is inserted into a slit formed in a formwork and concrete is poured into the formwork, so that a portion of the perforated steel plate dowel with holes is embedded in the concrete.

JP 2015-229855 A Patent No. 6807473

As mentioned above, the technology disclosed in Patent Document 1 can eliminate the need for on-site concrete pouring work, but there is room for improvement in that the split column-beam joints of a pair of precast beams may become misaligned during an earthquake.

Taking the above facts into consideration, the present invention aims to suppress the shifting of the split column-beam joint of a pair of precast beams during an earthquake.

The first aspect is a column-beam joint structure comprising a precast column, a pair of precast beams each having a split column-beam joint at the end that divides the column-beam joint of the precast column into left and right halves, the split column-beam joints being placed on the precast column with their joint surfaces facing each other, and a steel plate joined across the left and right split column-beam joints and having a shear force transmission means.

In the first embodiment of the beam-column joint structure, a pair of precast beams each have a split beam-column joint at the end, which divides the beam-column joint of the precast column into left and right halves. These split beam-column joints are placed on the precast column with their joint surfaces facing each other.

Here, the split column-beam joints are connected to each other by steel plates having shear force transmission means, which prevents the split column-beam joints from shifting during an earthquake. This improves earthquake resistance.

The second aspect is the column-beam joint structure described in the first aspect, in which the shear force transmission means is a hole formed in the steel plate.

In the second embodiment of the beam-column joint structure, the shear force transmission means is a hole formed in the steel plate, so the structure is simpler than, for example, when the shear force transmission means is a protrusion that protrudes from the plate surface of the steel plate.

The third aspect is the beam-column joint structure described in the second aspect, in which an anchor plate is provided at the tip of the beam reinforcement of a pair of the precast beams, and the anchor plate is located on the joint surface side of the hole in the steel plate.

In the third type of beam-column joint structure, the tensile force acting on the main beam reinforcement of a pair of precast beams is transmitted from the anchor plate at the tip to the steel plate through the holes in the steel plate.

The present invention makes it possible to suppress the displacement of the split column-beam joint of a pair of precast beams during an earthquake.

1 is a vertical cross-sectional view taken along line 1-1 in FIG. 2 , showing a lower precast column and a pair of precast beams to which a beam-column joint structure according to one embodiment is applied. 2 is a horizontal cross-sectional view taken along line 2-2 of FIG. 1. FIG. 4 is a front view of the steel plate as viewed from the Y direction. FIG. 2 is a schematic diagram 1A and 1B are elevation views illustrating a construction method for a column-beam joint structure according to one embodiment. FIG. 3 is a horizontal cross-sectional view corresponding to FIG. 2 , showing a first modified example of a column-beam joint structure according to one embodiment. FIG. 3 is a horizontal cross-sectional view corresponding to FIG. 2 and showing a second modified example of a column-beam joint structure according to one embodiment.

<Embodiment>
A column-beam joint structure according to an embodiment of the present invention will be described. Note that two directions perpendicular to the horizontal direction are the X direction and the Y direction, which are indicated by the arrows X and Y, respectively. Furthermore, the vertical direction perpendicular to the X direction and the Y direction is the Z direction, which is indicated by the arrow Z.

(Column-beam joint structure)
First, the specific structure of the column-beam structure will be described.

As shown in Figures 1 and 2, the column-beam joint structure 100 according to this embodiment includes a lower precast column 10 (see Figure 1), an upper precast column 20 (see Figure 1), and a pair of precast beams 30. The lower precast column 10 (see Figure 1) is an example of a precast column. The column-beam joint 16 is composed of a pair of split column-beam joints 34 split into left and right parts.

The longitudinal direction of the precast beam 30 is the X direction, and the beam width direction is the Y direction. The X direction is also the left-right direction.

As shown in FIG. 1, the lower precast column 10 is made of precast concrete. The cross-sectional shape of the lower precast column 10 is rectangular. A number of main column reinforcements 12 and a number of shear reinforcements 14 are embedded in the outer periphery of the lower precast column 10.

The multiple column main reinforcements 12 of the lower precast column 10 are arranged along the Z direction, which is the material axis direction of the lower precast column 10. The multiple column main reinforcements 12 are also arranged at intervals in the circumferential direction of the lower precast column 10. The upper ends of these column main reinforcements 12 protrude upward from the outer periphery of the upper surface 10U of the lower precast column 10. The upper precast column 20 is joined to the upper side of the lower precast column 10 via a column-beam joint 16.

The upper precast column 20 is made of precast concrete. The cross-sectional shape of the upper precast column 20 is rectangular, similar to the lower precast column 10. A number of main column reinforcements 22 and a number of shear reinforcements 24 are embedded in the outer periphery of the upper precast column 20. The cross-sectional shapes of the lower precast column 10 and the upper precast column 20 can be changed as appropriate.

The multiple column main reinforcements 22 of the upper precast column 20 are arranged along the Z direction, which is the material axis direction of the upper precast column 20. The multiple column main reinforcements 22 are also arranged at intervals in the circumferential direction of the upper precast column 20. The lower end side of each column main reinforcement 22 is inserted into a mechanical joint 26.

The multiple mechanical joints 26 are embedded in the lower end of the upper precast column 20 and open to the lower surface 20L of the upper precast column 20. Multiple column main reinforcements 12 protruding from the upper surface 10U of the lower precast column 10 are inserted into the lower end of each of these mechanical joints 26. In this state, the column main reinforcements 12 of the lower precast column 10 and the column main reinforcements 22 of the upper precast column 20 are connected via the mechanical joints 26 by filling the interior of each mechanical joint 26 with a filler G such as grout or mortar.

As shown in Figures 1 and 2, a pair of precast beams 30 are formed from precast concrete. Each precast beam 30 has a beam portion 32 and a pair of split beam-column joints 34 (see also Figure 4).

The beam section 32 is made of ordinary concrete, but is not limited to this. The cross-sectional shape of the beam section 32 is rectangular. A split beam-column joint section 34 is formed at each end of the longitudinal direction (material axis direction (X direction)) of the beam section 32 (see also Figure 4).

In this embodiment, the split column-beam joint 34 is formed from fiber-reinforced concrete, but is not limited to this. The fiber-reinforced concrete in this embodiment is concrete that contains fibers such as steel fibers, glass fibers, carbon fibers, and organic fibers.

The width in the Y direction of the split column-beam joint 34 is wider than the beam width of the beam section 32 (see Figures 2 and 4). The width in the Y direction of this split column-beam joint 34 is approximately the same as the width in the Y direction of the lower precast column 10 (see Figure 1) and the upper precast column 20 (see Figure 1).

The split column-beam joint 34 is placed on one side (approximately half of one side) of the upper surface 10U of the lower precast column 10 (see Figure 1). This split column-beam joint 34 forms approximately half of the column-beam joint 16. In other words, the split column-beam joint 34 divides the column-beam joint 16 approximately in half on the left and right (horizontal direction) (see also Figure 4). Note that the division position of the column-beam joint 16 is not limited to approximately half and can be changed as appropriate.

A number of beam main reinforcements 36 are embedded in the precast beam 30. The beam main reinforcements 36 are arranged along the X direction, which is the material axis direction of the precast beam 30. The beam main reinforcements 36 are embedded at the upper and lower ends of the precast beam 30 (see FIG. 1). The beam main reinforcements 36 are also arranged at intervals in the Y direction, which is the beam width direction of the precast beam 30 (see FIG. 2). The beam main reinforcements 36 are also arranged across the beam section 32 and the split beam-column joint section 34. The beam section 32 has shear reinforcement bars 37 embedded therein, surrounding the beam main reinforcements 36.

The tip of each beam main reinforcement 36 reaches the split column-beam joint 34. An anchor 38 having an anchor plate 39 at its tip is provided at the tip of each of the left and right beam main reinforcement 36 (see also Figure 4). Each anchor 38 is mechanically fixed, for example, by a plate nut, and is embedded in the split column-beam joint 34. These anchors 38 increase the anchor strength between the split column-beam joint 34 and the beam main reinforcement 36. The anchors 38 can be omitted as appropriate.

A number of insertion holes 40 are formed on the outer periphery of each divided column-beam joint 34. The multiple insertion holes 40 penetrate the divided column-beam joint 34 in the vertical direction. The multiple insertion holes 40 are also arranged at intervals in the circumferential direction of the column-beam joint 16. These insertion holes 40 are formed by embedding sheath pipes (cylindrical pipes) 42 in the divided column-beam joint 34.

In the divided beam-column joints 34, multiple shear reinforcement bars 50 are embedded to reinforce (shear reinforce) the beam-column joints 16. In plan view, the multiple shear reinforcement bars 50 are formed in a rectangular ring shape along the outer periphery of each beam-column joint 34, and are arranged to surround the outside of the sheath tube 42 (see Figure 2).

As shown in Figures 1, 2, and 4, a steel plate 120 (see also Figure 3) with multiple holes 122 formed therein as an example of a shear force transmission means is embedded in one of the divided column-beam joints 34 on the right side of the figure, and protrudes from the joint surface 34T described below.

As shown in Figures 1 and 3, in this embodiment, two rows of holes 123 are formed, each row having a plurality of holes 122 aligned in the vertical direction. One row of holes 123 on the right side of the figure is formed in a portion of the steel plate 120 that is embedded in one of the split column-beam joint sections 34, and the other row of holes 123 on the left side of the figure is formed in a portion of the steel plate 120 that protrudes from the joint surface 34T. In this embodiment, the steel plate 120 is embedded on both sides in the beam width direction (Y direction) as shown in Figures 2 and 4, but this is not limited to this.

As shown in Figures 1 and 3, a groove 150 is formed on the joint surface 34T of the other split column-beam joint 34 on the left side of the figure, into which the steel plate 120 protruding from one split column-beam joint 34 on the right side of the figure is inserted.

As shown in Figures 1 and 2, a pair of left and right precast beams 30 are placed on the upper surface 10U of the lower precast column 10 (see Figure 1) with the joint surfaces 34T of each split column-beam joint section 34 facing each other (close to each other) (see also Figure 4).

At this time, the steel plate 120 protruding from one of the divided column-beam joints 34 on the right side in Figures 2 and 4 is inserted into the groove 150 of the other divided column-beam joint 34 on the left side in the figures. In addition, the multiple column main reinforcements 12 protruding from the upper surface 10U of the lower precast column 10 are inserted (penetrated) in the vertical direction into the multiple insertion holes 40 (sheath tubes 42) of the divided column-beam joints 34 (see also Figure 5).

In this state, by filling each insertion hole 40 (sheath tube 42) with filler G, the split column-beam joint 34 is fixed to the lower precast column 10 (see Figure 1) via multiple column main reinforcements 12.

As shown in Figures 2 and 4, the gaps between the joint surfaces 34T of the opposing split column-beam joints 34 are filled with filler G. Furthermore, the grooves 150 are also filled with filler G, and the steel plates 120 inserted into the grooves 150 are embedded. In this way, adjacent split column-beam joints 34 are joined together, and a column-beam joint 16 is formed (see also Figure 1).

As shown in FIG. 4, the anchors 38 at the tips of the left and right beam main reinforcements 36 are located closer to the joint surface 34T than the holes 122 in the steel plate 120. To explain in more detail, the position M of the anchor plate 39 of the anchors 38 is located closer to the joint surface 34T than the position L1 of the tip of the hole 122.

(Column-beam joint structure)
Next, an example of a construction method for the beam-column joint structure according to this embodiment will be described.

Figure 5 (A) shows three lower precast columns 10 installed with a horizontal gap between them. For ease of explanation, the three lower precast columns 10 will be referred to as lower precast column 10A, precast column 10B, and precast column 10C from the left, and the precast beams 30 erected on the adjacent lower precast columns 10A, 10B, and 10C will be referred to as precast beam 30E and precast beam 30F from the left.

First, the split column-beam joints 34 on both sides of the precast beam 30E are placed on the upper surfaces 10U of the adjacent lower precast columns 10A, 10B. At this time, each split column-beam joint 34 is placed on one of the left and right sides of the upper surface 10U of the lower precast columns 10A, 10B. In addition, the multiple main column reinforcements 12 protruding from the upper surfaces 10U of the lower precast columns 10A, 10B are inserted into the multiple insertion holes 40 (sheath tubes 42, see Figures 1 and 2) of the split column-beam joints 34, and protrude from the upper surfaces 34U of the split column-beam joints 34.

In addition, the gap between the upper surface 10U of the lower precast column 10 and the lower surface of the beam-column joint 16 (the lower surface 34L of the divided beam-column joint 34) is appropriately filled with a filler such as grout or mortar for level adjustment (see Figure 1).

Next, the split column-beam joints 34 on both sides of the precast beam 30F are placed on the upper surfaces 10U of the adjacent lower precast columns 10B, 10C. At this time, the split column-beam joints 34 are placed on either the left or right side of the upper surface 10U of the lower precast columns 10B, 10C. In addition, the multiple main column reinforcements 12 protruding from the upper surface 10U of the lower precast columns 10B, 10C are inserted into the multiple insertion holes 40 (sheath tubes 42, see Figures 1 and 2) of each split column-beam joint 34, and protrude from the upper surface 34U of the split column-beam joints 34.

As shown in Figure 2, a pair of precast beams 30E, 30F are arranged so that the joint surfaces 34T of the respective split beam-column joint sections 34 face each other and are close to each other, and the steel plate 120 protruding from one split beam-column joint section is inserted into the groove section 150 of the other split beam-column joint section 34 (see also Figure 4).

Next, the filling material G is filled into each of the multiple insertion holes 40 (sheath tubes 42) of each divided column-beam joint 34. This joins each divided column-beam joint 34 to the lower precast column 10 via multiple column main reinforcements 12.

Furthermore, the gaps (joints) and grooves 150 of the joint surfaces 34T of adjacent divided column-beam joints 34 are filled with filler G. This joins the adjacent divided column-beam joints 34 together, forming the column-beam joints 16 (see also Figure 4).

Next, as shown in FIG. 5(B), the upper precast column 20 is placed on the top surface of the column-beam joint 16 formed by the adjacent divided column-beam joints 34. At this time, as shown in FIG. 1, the multiple column main reinforcements 12 of the lower precast column 10 protruding from the upper surface 34U of each divided column-beam joint 34 are inserted into the multiple mechanical joints 26 embedded in the lower end of the upper precast column 20. In this state, the mechanical joints 26 are filled with filler G. This connects the column main reinforcements 12 of the lower precast column 10 and the column main reinforcements 22 of the upper precast column 20 via the mechanical joints 26.

In addition, the gap between the upper surface of the beam-column joint 16 (upper surface 34U of the divided beam-column joint 34) and the lower surface 20L of the upper precast column 20 is appropriately filled with a filler such as grout or mortar for level adjustment.

The order of the above construction steps (procedures) may be changed as appropriate depending on the situation.

<Action and Effects>
Next, the operation and effects of this embodiment will be described.

In the column-beam joint structure 100 of this embodiment, a pair of precast beams 30 each have a split column-beam joint 34 at their ends, which is the left and right division of the column-beam joint 16 of the lower precast column 10. These split column-beam joints 34 are placed on the lower precast column 10 with their respective joint surfaces 34T facing each other.

Here, the split column-beam joints 34 are connected to each other by a steel plate 120 with multiple holes 122, which prevents the split column-beam joints 34 from shifting during an earthquake. This improves earthquake resistance.

The multiple holes 122 in the steel plate 120 function as a shear force transmission means, and the shear force is transmitted. In addition, compared to a case where the shear force transmission means is a protrusion protruding from the plate surface of the steel plate 120, for example, the structure is simpler and the width can be made smaller.

The tensile force acting on the beam reinforcement bars 36 of the pair of left and right precast beams 30 is transmitted from the anchors 38 at the tips to the steel plate 120 through the holes 122 in the steel plate 120, and is further transmitted between the left and right split column-beam joints 34 via the steel plate 120. Therefore, the shifting of the split column-beam joints 34 during an earthquake is further suppressed.

As shown in FIG. 4, the anchors 38 at the tips of the left and right beam main reinforcements 36 are located closer to the joint surface 34T than the holes 122 in the steel plate 120. Explaining in more detail, the position M of the anchor plate 39 of the anchor 38 is located closer to the joint surface 34T than the position L1 of the tip of the hole 122. Therefore, the tensile force acting on the beam main reinforcements 36 is effectively transmitted from the anchor plate 39 to the steel plate 120 via the holes 122 in the steel plate 120.

It is preferable that the position M of the fixing plate 39 of the fixing body 38 is located closer to the joining surface 34T than the position L1 of the tip of the hole 122, but this is not limited to this. It is sufficient that the position M of the fixing plate 39 is located closer to the joining surface 34T than the position L2 of the rear end of the hole 122.

In addition, even if the position M of the fixing plate 39 is not located closer to the joint surface 34T than the position L2 of the rear end of the hole 122, the effect of increasing the joint strength between the end of the beam main reinforcement 36 and the split column-beam joint section 34 is still achieved. Therefore, in this embodiment, mechanical joints or the like that connect the beam main reinforcement 36 of a pair of precast beams 30 (30X, 30Y) can be omitted. Therefore, the workability of the pair of precast beams 30 is further improved.

In addition, because adjacent beam-column joints 34 are formed from fiber-reinforced concrete, the splitting strength of the beam-column joints 34 is increased. This allows the number of shear reinforcement bars 50 embedded in the beam-column joints 34 to be reduced. This simplifies the configuration of the beam-column joints 34, improving the manufacturability of a pair of precast beams 30.

<Modification>
Next, a modification of this embodiment will be described.

[First Modification]
In the first modified example shown in FIG. 6 , a steel beam 200 is connected to a connection member 250 fixed to a side surface of the beam-column connection portion 16 .

The connection member 250 is configured with a fixing plate 252 and a connecting plate 254 that form a T-shape in plan view. The fixing plate 252 is fastened and fixed with a nut 222 to an anchor bolt 220 embedded in the left and right split column-beam joints 34 that constitute the column-beam joint 16.

The steel beam 200 is composed of an H-shaped steel having a flange 202 and a web 204. The web 204 of the steel beam 200 is connected to the connection plate 254 of the connection member 250 by fastening it with a bolt 260 and a nut 262.

The connection plate 254 of the connection member 250 is fixed across the left and right split beam-column joints 34. This further reduces the misalignment of the split beam-column joints 34 during an earthquake.

[Second Modification]
In a second modified example shown in FIG. 7 , a reinforced concrete beam 300 is joined to the side surface of the beam-column connection portion 16 .

The reinforced concrete beam 300 is provided with beam main reinforcement ends 302 and beam main reinforcement bodies 304. The beam main reinforcement ends 302 and beam main reinforcement bodies 304 are surrounded by multiple shear reinforcement bars (not shown).

The beam main reinforcement end 302 is embedded and protrudes from the left and right split beam-column joints 34 that make up the beam-column joint 16. An anchor 310 is provided at the tip of the beam main reinforcement end 302. The beam main reinforcement body 304 is connected to the beam main reinforcement end 302 via a mechanical joint 306.

The reinforced concrete beam 300 is fixed across the left and right split beam-column joints 34. This further reduces the displacement of the split beam-column joints 34 during an earthquake.

＜Other＞
The present invention is not limited to the above embodiment.

For example, in the above embodiment, two rows of holes 123 are formed, each row having a plurality of holes 122 aligned in the vertical direction, but this is not limited to this. Three or more rows of holes 123 may be formed.

For example, in the above embodiment, the steel plate 120 is embedded in one of the divided column-beam joints 34 in advance, but this is not limited to this. The steel plate 120 may not be embedded in either of the divided column-beam joints 34, and a groove 150 may be formed in the joint surface 34T of both divided column-beam joints 34.

For example, in the above embodiment, the steel plate 120 is provided on both sides in the beam width direction (Y direction), but this is not limited to this. The steel plate 120 may be provided in one or three or more locations. The steel plate 120 may also be divided in the vertical direction. In other words, multiple steel plates may be provided side by side in the vertical direction.

In addition, for example, in the above embodiment, the shear force transmission means is the hole 122 formed in the steel plate 120, but is not limited to this. For example, the shear force transmission means may be a protrusion such as a stud protruding from the plate surface of the steel plate 120. Alternatively, the shear force transmission means may be a concave or convex portion formed on the plate surface of the steel plate 120. Alternatively, the shear force may be transmitted by forming the steel plate 120 in a curved, wavy shape.

In addition, for example, a recess (cotter) into which the filler material G is filled may be formed on the joint surface 34T of the divided column-beam joint portion 34.

In addition, for example, in the above embodiment, the divided column-beam joint 34 is formed from fiber-reinforced concrete, but this is not limited to this. For example, the divided column-beam joint 34 may be formed from ordinary concrete.

For example, in the above embodiment, the column main reinforcement bars 12 protruding from the upper surface of the lower precast column 10 are inserted into the multiple insertion holes 40 (sheath tubes 42) of the divided column-beam joint section 34, but this is not limited to the above. The column main reinforcement bars protruding from the lower surface of the upper precast column 20 may be inserted into the multiple insertion holes 40 (sheath tubes 42) of the divided column-beam joint section 34. In this case, for example, the column main reinforcement bars 22 of the upper precast column 20 penetrate the divided column-beam joint section 34 in the vertical direction and are connected to the column main reinforcement bars 12 of the lower precast column 10 via a mechanical joint embedded in the upper end of the lower precast column 10.

For example, in the above embodiment, the precast beam 30 is formed from full precast concrete. However, the precast beam may be formed from half precast concrete. In other words, the precast beam in the above embodiment is a concept that includes full precast beams and half precast beams.

Furthermore, the present invention may be implemented in various ways without departing from the spirit of the invention. Multiple embodiments and variations may be implemented in combination as appropriate.

10 Lower precast column (an example of a precast column)
10U Upper surface 16 Column-beam joint 30 Precast beam 32 Beam 34 Split column-beam joint 36 Beam main reinforcement 39 Anchorage plate 100 Column-beam joint structure 120 Steel plate 122 Hole (an example of a shear force transmission means)

Claims (6)

Precast columns and
A pair of precast beams each having a split column-beam joint portion at one end, the split column-beam joint portion being formed by dividing the column-beam joint portion of the precast column into a left and a right part, the split column-beam joint portion being placed on the precast column with their joint surfaces facing each other;
A steel plate joined across the left and right divided column-beam joints and having a shear force transmission means;
Equipped with
the shear force transmission means is a hole formed in the steel plate,
An anchor plate is provided at the tip of the beam main reinforcement of the pair of precast beams,
The fixing plate is located on the joining surface side of the hole of the steel plate.
Column-beam joint structure. Precast columns and
A pair of precast beams each having a split column-beam joint portion at one end, the split column-beam joint portion being formed by dividing the column-beam joint portion of the precast column into a left and a right part, the split column-beam joint portion being placed on the precast column with their joint surfaces facing each other;
A steel plate having a shear force transmission means, one end of which is embedded in one of the divided column-beam joints and the other end of which protrudes from the joint surface and is inserted into a groove formed in the other divided column-beam joint;
A filler material is filled in the groove portion and integrates the one divided column-beam joint portion and the other divided column-beam joint portion;
A column- beam joint structure. The shear force transmission means is a hole formed in the steel plate.
The column-beam joint structure according to claim 2 . An anchor plate is provided at the tip of the beam main reinforcement of the pair of precast beams,
The fixing plate is located on the joining surface side of the hole of the steel plate.
The column-beam joint structure according to claim 3. The fixing plate of the connection member to which the steel beam is connected is arranged across the side surfaces of the left and right split column-beam joint portions,
The fixing plate is fastened and fixed to the anchor bolts embedded in the left and right divided column-beam joints with nuts.
The column-beam joint structure according to any one of claims 1 to 4. A ring-shaped shear reinforcement bar is embedded in each of the divided column-beam joints on one side and the divided column-beam joints on the other side.
The column-beam joint structure according to any one of claims 1 to 5.