JP7610953B2 - Beam and slab joint structure - Google Patents

Description

The present invention relates to a joint structure between a beam and a slab.

Conventionally, a precast concrete slab placed on a beam is joined to the beam by placing a pair of slabs on both ends of the beam in the beam width direction with their end faces facing each other, and pouring concrete between the end faces of the opposing slabs (see, for example, Patent Documents 1 and 2).

Japanese Patent Application Publication No. 9-165860 JP 2009-155850 A

However, with this joining method, concrete must be poured to join the precast concrete slab to the beam, which is time-consuming.

Taking the above into consideration, the present invention aims to eliminate or reduce the concrete pouring work required to join a precast concrete slab to a beam.

The beam-slab joint structure according to the first aspect includes a reinforced concrete beam, a precast reinforced concrete slab placed on the beam, a hole formed through the slab so as to be located on the beam, a shear force transmission member having a lower end embedded in the beam and an upper end inserted into the hole, and having a first surface portion along the beam length direction of the beam, and a first through hole formed in the first surface portion that penetrates the upper end in a lateral direction perpendicular to the beam length direction of the beam, and a filler material filled in the hole into which the upper end of the shear force transmission member is inserted.

According to the beam-slab joint structure of the first aspect, the shear force transmission member allows the slab to be joined to the beam so that it is rigid in the beam length direction, and a high degree of integration between the beam and the slab can be achieved. This allows the slab cross section to be taken into account in the beam stiffness evaluation, and further allows the slab reinforcing bars to be taken into account in the beam strength evaluation.

In addition, the slab is joined to the beam by filling the hole into which the upper end of the shear force transmission member is inserted with a filler material, eliminating or reducing the amount of concrete pouring required to join the slab to the beam.

The beam-slab joint structure according to the second aspect is the beam-slab joint structure according to the first aspect, in which the shear force transmission member has a second surface portion perpendicular to the first surface portion, and a second through hole penetrating the upper end portion in the beam length direction is formed in the second surface portion.

According to the beam-slab joint structure of the second aspect, the shear force transmission member allows the slab to be joined to the beam so as to be rigid in the lateral direction perpendicular to the beam length direction.

The beam-slab joint structure of the third aspect is the beam-slab joint structure of the second aspect, in which the shear force transmission member is an angle bar, and the first through hole is formed on one side of the angle bar, and the second through hole is formed on the other side of the angle bar.

According to the beam-slab joint structure of the third aspect, a first through hole is formed on one side of the angle bar, and a second through hole is formed on the other side of the angle bar, so that through holes can be easily formed in the lateral direction perpendicular to the beam length direction and in the beam length direction.

The present invention has the above-mentioned configuration, which makes it possible to eliminate or reduce the concrete pouring work required to join a precast concrete slab to a beam.

FIG. 2 is a plan view showing a standard floor of a building according to one embodiment. FIG. 2 is a plan view showing a joint structure between a beam and a slab according to one embodiment. This is a cross-sectional view taken along line 3-3 in Figure 2. 4(a) to (c) are perspective views showing a shear force transmission member according to one embodiment. FIG. 2 is a perspective view showing a slab-to-slab joint structure according to one embodiment. FIG. 2 is a plan view showing a slab-to-slab joint structure according to one embodiment. 7(a) to (c) are side views showing the construction procedure for joining slabs together. FIG. 2 is a side view showing a joint structure between a column and a slab according to one embodiment. FIG. 2 is a plan view showing a joint structure between a column and a slab according to one embodiment. 10(a) to (d) are elevation views showing a construction procedure for a building according to one embodiment. 1 is a front cross-sectional view showing a variation of a joint structure between a beam and a slab according to one embodiment. FIG. 1 is a front cross-sectional view showing a variation of a joint structure between a beam and a slab according to one embodiment. FIG. FIG. 11 is a side view showing a variation of a joint structure between a column and a slab according to one embodiment.

Below, we will explain the beam-to-slab joint structure according to one embodiment, with reference to the drawings.

The plan view of Figure 1 shows a reference floor 12 of a building 10. The reference floor 12 is composed of precast reinforced concrete columns 14, fully precast reinforced concrete beams 16 erected between adjacent columns 14, and a fully precast concrete slab (hereinafter referred to as "PCa slab 18") supported by the beams 16.

The PCa slab 18 is joined to the beam 16 by a beam-to-slab joint structure 20, adjacent PCa slabs 18 are joined to each other by a slab-to-slab joint structure 22, and the PCa slab 18 is joined to the column 14 by a column-to-slab joint structure 24.

(Beam and slab joint structure)
As shown in the plan view of Figure 2 and in Figure 3, which is a cross-sectional view along line 3-3 of Figure 2, the beam-to-slab joint structure 20 is composed of a beam 16, a PCa slab 18 placed on the beam 16, a hole 26 formed by penetrating the PCa slab 18 in the vertical direction so as to be located on the beam 16, an angle iron 28 as a shear force transmission member, and concrete 30 as a filler material.

As shown in the perspective view of FIG. 4(a), the angle iron 28 is a member formed by connecting a flat plate portion 32 made of a steel plate constituting one side and a flat plate portion 34 made of a steel plate constituting the other side at right angles to form an L-shaped structural cross section. The angle iron 28 has a first surface portion 36 that constitutes the outer surface of the flat plate portion 32, and a second surface portion 38 that constitutes the outer surface of the flat plate portion 34 and is perpendicular to the first surface portion 36.

As shown in FIG. 3, the lower end of the angle iron 28 is embedded in the beam 16 and the upper end is inserted into the hole 26. In this state, as shown in FIG. 2, the first surface portion 36 is arranged along the beam length direction of the beam 16 (hereinafter referred to as "beam length direction X"), and the second surface portion 38 is arranged along the beam width direction of the beam 16 (hereinafter referred to as "beam width direction Y"), which is a horizontal direction perpendicular to the beam length direction X.

As shown in FIG. 4(a), a first through hole 40 is formed in the first surface 36 of the angle iron 28, penetrating the angle iron 28 in the beam width direction Y, and a second through hole 42 is formed in the second surface 38 of the angle iron 28, penetrating the angle iron 28 in the beam length direction X. That is, the first through hole 40 is formed in one side of the angle iron 28, and the second through hole 42 is formed in the other side of the angle iron 28. As shown in FIG. 3, the first through hole 40 and the second through hole 42 formed in the upper end of the angle iron 28 are arranged within the hole 26.

As shown in Figures 2 and 3, concrete 30 as filler is filled into the hole 26 into which the upper end of the angle iron 28 is inserted and hardened.

As shown in Figures 2 and 3, reinforcing bars 44 are embedded in the PCa slab 18 so that they are arranged around the hole 26 on all four sides. These reinforcing bars 44 reinforce the PCa slab 18 around the hole 26 and also facilitate the transmission of force from the beam 16 to the PCa slab 18.

(Slab-to-slab joint structure)
As shown in the oblique view of Figure 5 and the plan view of Figure 6, one PCa slab 18 (hereinafter referred to as "PCa slab 18A") and the other PCa slab 18 (hereinafter referred to as "PCa slab 18B") arranged opposite each other are joined by a slab-to-slab joining structure 22.

The slab-to-slab joint structure 22 is configured to include loop joint bars 48 provided on the PCa slab 18A and extending from the end surface 46 of the PCa slab 18A, loop joint bars 52 provided on the PCa slab 18B and extending from the end surface 50 of the PCa slab 18B, a base plate portion 54 protruding from the end surface 46 of the PCa slab 18A and provided below the loop joint bars 48, a base plate portion 56 protruding from the end surface 50 of the PCa slab 18B and provided below the loop joint bars 52, a filler portion 58 formed between the end surface 46 of the PCa slab 18A and the end surface 50 of the PCa slab 18B, and concrete 60 poured into the filler portion 58 and hardened.

As shown in FIG. 6, the loop joint bars 48 and the loop joint bars 52 are arranged alternately in the beam width direction Y, overlapping by a predetermined length T1.

As shown in the side view of FIG. 7(a), the length L1 of the bottom plate portion 54 of the PCa slab 18A is shorter than the length D1 of the loop joint reinforcement 48, and the length L2 of the bottom plate portion 56 of the PCa slab 18B is approximately the same as the length D2 of the loop joint reinforcement 52.

PCa slabs 18A and 18B are joined by the construction procedure shown in the side views of Figures 7(a) to (c). First, as shown in Figure 7(a), in the first step, with PCa slab 18B installed in a predetermined position, PCa slab 18A is dropped straight down from above so that the end face 84 of bottom plate portion 54 of PCa slab 18A butts against the end face 86 of bottom plate portion 56 of PCa slab 18B. At this time, the loop joint bars 48 of PCa slab 18A are dropped straight down so as not to interfere with the loop joint bars 52 of PCa slab 18B.

Next, in the second step, as shown in FIG. 7(b), concrete 60 is poured into the filling portion 58 by casting in place and allowed to harden. This joins the PCa slabs 18A and 18B together as shown in FIG. 7(c).

In the slab-to-slab joint structure 22, as shown in FIG. 6, the loop joint reinforcement 48 provided in the PCa slab 18A and the loop joint reinforcement 52 provided in the PCa slab 18B are connected by a loop lap joint, thereby shortening the predetermined length T1 over which the loop joint reinforcement 48 and the loop joint reinforcement 52 overlap, and shortening the length of the filling portion 58. This allows the amount of concrete 60 poured into the filling portion 58 to be reduced.

In addition, in the slab-to-slab joint structure 22, as shown in Figures 7(a) and (b), by making the length L1 of the bottom plate portion 54 of the PCa slab 18A shorter than the length D1 of the loop joint reinforcement 48, the PCa slab 18A can be dropped straight down from above so that the end face 84 of the bottom plate portion 54 of the PCa slab 18A butts against the end face 86 of the bottom plate portion 56 of the PCa slab 18B. In other words, the PCa slab 18A can be installed by moving it up and down.

(Column and slab joint structure)
As shown in the side view of FIG. 8 and the plan view of FIG. 9, the column 14 and the PCa slab 18 are joined by a column-slab joint structure 24 .

The slab joint structure 24 is composed of a loop joint bar 64 provided on the column 14 and extending from the side surface 62 of the column 14, a loop joint bar 68 provided on the PCa slab 18 and extending from the end surface 66 of the PCa slab 18, a filler section 70 formed between the side surface 62 of the column 14 and the end surface 66 of the PCa slab 18, and concrete 72 poured into the filler section 70 and hardened.

As shown in FIG. 9, the loop joint bars 64 and the loop joint bars 68 are arranged alternately in the beam width direction Y, overlapping by a predetermined length T2.

In the column-slab joint structure 24, as shown in FIG. 9, the loop joint reinforcement 64 provided on the column 14 and the loop joint reinforcement 68 provided on the PCa slab 18 are connected by a loop lap joint, so that the force transmitted from the beam 16 to the PCa slab 18 can be reliably transmitted to the column 14. In addition, the predetermined overlap length T2 between the loop joint reinforcement 64 and the loop joint reinforcement 68 can be shortened, and the length of the filling portion 70 can be shortened. This allows the amount of concrete 72 poured into the filling portion 70 to be reduced.

(How the building is constructed)
The building 10 is constructed according to the construction procedures shown in the elevation views of Figures 10(a) to 10(d). Here, the construction procedures will be described from the step of constructing a lower floor slab 74 by installing multiple PCa slabs 18 as shown in Figure 10(a) to the step of constructing an upper floor slab 76 by installing multiple PCa slabs 18 as shown in Figure 10(d).

First, as shown in FIG. 10(a), in the first step, multiple PCa slabs 18 are placed on beams 16 (referred to as "beams 16A") installed on columns 14 (referred to as "columns 14A"), and the PCa slabs 18 are supported by shoring 82. In this state, the PCa slabs 18 are joined to the beams 16A by the beam-to-slab joint structure 20 (see FIG. 3), the PCa slabs 18 are joined to each other by the slab-to-slab joint structure 22 (see FIG. 5), and the PCa slabs 18 are joined to the columns (joints 78 of the beams 16A) by the column-to-slab joint structure 24 (see FIG. 8). Then, the shoring 82 is removed, and the slab 74 of the lower floor is constructed.

Next, as shown in FIG. 10(b), in the second step, a pillar 14 (hereinafter referred to as "pillar 14B") is installed on the joint portion 78 of the beam 16A.

Next, as shown in FIG. 10(c), in the third step, shoring 80 is installed on the PCa slab 18 that constitutes the slab 74 of the lower floor.

Next, as shown in FIG. 10(c), in the fourth step, a beam 16 (hereinafter referred to as "beam 16B") is placed on the column 14B and the beam 16B is supported by a support 80. In this state, the joint portion 78 of the beam 16B is joined to the column 14B.

Next, as shown in FIG. 10(d), in the fifth step, after removing the shoring 80, the shoring 82 is installed on the PCa slab 18 that constitutes the slab 74 of the lower floor. Note that the shoring 80 may be used as the shoring 82 without being removed.

Next, as shown in FIG. 10(d), in the sixth step, the PCa slab 18 is placed on the beam 16B and supported by shoring 82. In this state, the PCa slab 18 is joined to the beam 16B by the beam-to-slab joint structure 20 (see FIG. 3), the PCa slabs 18 are joined to each other by the slab-to-slab joint structure 22 (see FIG. 5), and the PCa slab 18 is joined to the column (joint portion 78 of the beam 16B) by the column-to-slab joint structure 24 (see FIG. 8). As a result, multiple PCa slabs 18 are installed on the beam 16B to construct the upper floor slab 76.

(effect)
Next, the effects of this embodiment will be described.

According to the beam-slab joint structure 20 of this embodiment, as shown in Figures 2, 3, and 4(a), the concrete 30 that has entered the first through hole 40 of the angle iron 28 and hardened resists the force in the beam length direction X acting on the angle iron 28. As a result, the PCa slab 18 can be joined to the beam 16 so as to be rigid in the beam length direction X by the angle iron 28 as a shear force transmission member, and a high degree of integration between the beam 16 and the PCa slab 18 can be achieved. As a result, the slab cross section of the PCa slab 18 can be taken into account in the rigidity evaluation of the beam 16, and furthermore, the reinforcing bars of the PCa slab 18 can be taken into account in the strength evaluation of the beam 16.

In addition, the hardened concrete 30 that has entered the first through hole 40 of the angle iron 28 resists the vertical forces acting on the angle iron 28. This makes it possible to prevent the PCa slab 18 from lifting up.

Furthermore, the concrete 30 that has entered the second through hole 42 of the angle iron 28 and hardened resists the force acting on the angle iron 28 in the beam width direction Y. This allows the angle iron 28, acting as a shear force transmission member, to join the beam 16 to the PCa slab 18 so that it is rigid in the beam width direction Y, achieving a high degree of integration between the beam 16 and the PCa slab 18.

In addition, the concrete 30 that has entered the second through hole 42 of the angle iron 28 and hardened resists the vertical forces acting on the angle iron 28. This makes it possible to prevent the PCa slab 18 from lifting up.

In addition, according to the beam-to-slab joint structure 20 of this embodiment, as shown in Figures 2 and 3, the PCa slab 18 is joined to the beam 16 by filling the holes 26 formed in the PCa slab 18 with concrete 30 as a filler into the holes 26 into which the upper ends of the angle members 28 are inserted, thereby reducing the amount of concrete pouring work required to join the PCa slab 18 to the beam 16.

Furthermore, according to the beam-to-slab joint structure 20 of this embodiment, as shown in FIG. 4(a), the shear force transmission member is an angle bar 28, and a first through hole 40 is formed on one side of the angle bar 28, and a second through hole 42 is formed on the other side of the angle bar 28, so that through holes can be easily formed in the beam width direction Y and the beam length direction X.

In addition, according to the beam-slab joint structure 20 of this embodiment, as shown in FIG. 3, the slab is made of a PCa slab 18, which is a precast member, so that the support work for supporting the slab can be reduced. In addition, the amount of construction work such as reinforcing bars, formwork, and concrete work performed on site can be reduced.

Furthermore, according to the beam-slab joint structure 20 of this embodiment, as shown in FIG. 10(c), by using PCa slabs 18, which are full precast members, as the slabs, after placing multiple PCa slabs 18 on the beams 16, the support structure 80 supporting the beams 16B placed above the PCa slabs 18 can be installed early, thereby allowing the beams 16B to be installed early. This makes it possible to shorten the construction period of the building 10 and reduce construction costs.

In addition, because the slab is a PCa slab 18, which is a full precast material, and the installation of this PCa slab 18 can be performed quickly, work that was previously performed on the beam 16, such as grouting work to join the joint portion 78 of the beam 16 to the column 14, can be performed on the PCa slab 18. In addition, a material storage area can be secured on the PCa slab 18, reducing the labor required to replace temporary rebar.

(Modification)
Next, a modification of the above embodiment will be described.

In the above embodiment, as shown in FIG. 4(a), an example in which the shear force transmission member is an angle bar 28 is shown, but the shear force transmission member may be a member of other shapes such as a rod shape, a plate shape, a square tube shape, a cylinder shape, etc. The perspective view of FIG. 4(b) shows an example of a steel plate 88 as a shear force transmission member. The steel plate 88 is arranged so as to be L-shaped in a plan view. When the shear force transmission member is a steel plate 88, the steel plate 88 may be arranged so as to be L-shaped in a plan view, or the steel plate 88 may be arranged so as to be cross-shaped or T-shaped in a plan view. The perspective view of FIG. 4(c) shows an example of a square steel pipe 90 as a shear force transmission member. Also, for example, the shear force transmission member may be a channel steel having a U-shaped cross section, and a first through hole 40 may be formed in one of the web or flange of this channel steel, and a second through hole 42 may be formed in the other of the web or flange.

In addition, in the above embodiment, as shown in FIG. 2, an example was shown in which one angle iron 28 was placed as a shear force transmission member in the hole 26 formed in the PCa slab 18, but multiple shear force transmission members may be placed in one hole 26.

In addition, in the above embodiment, as shown in FIG. 3, an example was shown in which the hole 26 formed in the PCa slab 18 and into which the upper end of the angle iron 28 was inserted was filled with concrete 30 as a filler, but the filler filled in the hole 26 may be other materials such as mortar. If the filler filled in the hole 26 is a material other than concrete, it is possible to eliminate the need to pour concrete to join the PCa slab 18 to the beam 16.

In the above embodiment, as shown in FIG. 3, an example was shown in which the slab was a PCa slab 18 made of fully precast concrete, but the slab may also be a PCa slab 92, 94 made of half precast concrete, as shown in the beam-to-slab joint structures 96, 98 shown in the front cross-sectional views of FIG. 11 and FIG. 12.

As shown in FIG. 11, in the beam-slab joint structure 96, the thickness of the portion 100 of the PCa slab 92 located on the beam 16 is the same as that of the PCa slab 18, which is a fully precast component that does not require pouring of post-cast concrete 102. Post-cast concrete 102 has been poured and hardened on the PCa slab 92 other than the portion 100.

Even in the beam-to-slab joint structure 96, the thickness of the portion 100 is the same as that of the PCa slab 18, which is a fully precast component that does not require the pouring of post-cast concrete 102. Therefore, after the PCa slab 92 is placed on the beam 16, the support structure that supports the beam 16 placed above the PCa slab 92 can be installed on the PCa slab 92 at an early stage, thereby allowing the beam 16 placed above the PCa slab 92 to be installed at an early stage.

In addition, the PCa slab 92 is joined to the beam 16 by filling the holes 26 formed in the PCa slab 92 with concrete 30 as a filler into the holes 26 into which the upper ends of the angle irons 28 are inserted, so that the concrete pouring work required to join the PCa slab 92 to the beam 16 can be reduced.

As shown in Figure 12, in the beam-to-slab joint structure 98, post-cast concrete 102 is poured and hardened on the PCa slab 94.

In the beam-to-slab joint structure 98, the PCa slab 94 is joined to the beam 16 by filling the holes 26 formed in the PCa slab 94 and into which the upper ends of the angle irons 28 are inserted with concrete 30 as a filler, so the amount of concrete poured to join the PCa slab 94 to the beam 16 is less than the amount of concrete poured in the gap on the beam formed between opposing half precast slabs to join a conventional half precast slab to a beam. In other words, the amount of concrete pouring work to join the PCa slab 94 to the beam 16 can be reduced.

In addition, even in the beam-to-slab joint structure 98, if a base frame such as a concrete block is placed on the PCa slab 94 and shoring is then installed on top of this, the shoring installation work can be carried out quickly.

In addition, in the above embodiment, as shown in Figure 1, an example was shown in which the columns were precast reinforced concrete columns 14, but the columns may be of other constructions, such as SRC, steel frame, or cast-in-place reinforced concrete.

In the above embodiment, as shown in FIG. 1, an example was shown in which the beams were fully precast and made of reinforced concrete (beam 16), but the beams may also be half precast and made of reinforced concrete.

In the above embodiment, as shown in Figs. 8 and 9, the loop joint bar 64 provided on the column 14 and the loop joint bar 68 provided on the PCa slab 18 are connected by a loop lap joint to join the column 14 and the PCa slab 18. However, if the slab is a PCa slab 94 made of half precast reinforced concrete, a relay joint 106 may be used to connect the reinforcing bar 108 provided on the column 14 to the reinforcing bar 110 provided in the post-cast concrete 102 poured on the PCa slab 94, as shown in the column-slab joint structure 104 in the side view of Fig. 13.

In the column-slab joint structure 104, a relay joint 106 to which a reinforcing bar 108 provided on the column 14 is joined is embedded in the side surface 62 of the column 14, and a reinforcing bar 112 is screwed and attached to the relay joint 106. The reinforcing bar 112 is then connected to a reinforcing bar 110 provided in the post-cast concrete 102 poured on the PCa slab 94 by a lap joint.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and one embodiment and various modified examples may be used in appropriate combination, and the present invention may of course be embodied in various forms without departing from the spirit of the present invention.

16 Beam 18, 92, 94 PCa slab (slab)
20, 96, 98 Beam and slab joint structure 26 Hole 28 Angle material (shear force transmission member)
30 Concrete (filler)
36 First surface portion 38 Second surface portion 40 First through hole 42 Second through hole 88 Steel plate (shear force transmission member)
90 Square steel pipe (shear force transmission member)
X Beam length direction Y Beam width direction

Claims (4)

Reinforced concrete beams and
a precast reinforced concrete slab placed on the beam;
a hole formed through the slab so as to be located on the beam;
a shear force transmission member having a lower end embedded in the beam and an upper end exposed from the beam and inserted into the hole, the shear force transmission member having a first surface portion along the beam length direction of the beam, the first surface portion having a first through hole formed in the upper end and the lower end thereof, the first through hole penetrating in a lateral direction perpendicular to the beam length direction of the beam ;
a filler material filled in the hole into which the upper end of the shear force transmission member is inserted;
A beam and slab joint structure having The beam-slab joint structure according to claim 1, wherein the shear force transmission member has a second surface portion perpendicular to the first surface portion, and a second through hole penetrating the upper end portion in the beam length direction of the beam is formed in the second surface portion. The beam-slab joint structure according to claim 2, wherein the shear force transmission member is an angle bar, the first through hole is formed on one side of the angle bar, and the second through hole is formed on the other side of the angle bar. Reinforced concrete beams and
a precast reinforced concrete slab placed on the beam;
a hole formed through the slab so as to be located on the beam;
a shear force transmission member having a lower end embedded in the beam and an upper end inserted into the hole, the shear force transmission member having a first surface along a beam length direction of the beam and a second surface perpendicular to the first surface, a first through hole penetrating the upper end in a lateral direction perpendicular to the beam length direction of the beam formed in the first surface, and a second through hole penetrating the upper end in the beam length direction of the beam formed in the second surface;
a filler material filled in the hole into which the upper end of the shear force transmission member is inserted;
having
The shear force transmission member is an angle iron, and the first through hole is formed on one side of the angle iron, and the second through hole is formed on the other side of the angle iron.