JP7515343B2 - Earthquake-resistant walls and earthquake-resistant wall construction methods - Google Patents

Description

The present invention relates to a seismic wall and a method for constructing a seismic wall.

One method for forming a structure is to inject a second mortar into an outer shape forming body made of a first mortar (see, for example, Patent Document 1).
Another method for forming a structure includes a construction method in which a second water-soluble mixture is filled into a compartment of a shell wall portion having a closed periphery made of a first water-soluble mixture to construct a composite structure (see, for example, Patent Document 2).

JP 2020-26099 A JP 2018-199939 A

Patent Document 1 describes a method for forming a structure, but does not describe the structure of a seismic wall capable of ensuring high durability against earthquake forces, which is desirable for a seismic wall, or a method for constructing the seismic wall.
Furthermore, Patent Document 2 describes a method for forming a footing, and states that the method is applicable to composite structures with a large base area, such as beams and columns. However, it does not describe the structure of an earthquake-resistant wall that can ensure high durability against seismic forces, which is desirable for an earthquake-resistant wall, or a method for constructing the earthquake-resistant wall.

In consideration of the above, the present invention aims to provide a seismic wall with high durability against earthquake forces, and a method for constructing the seismic wall.

The earthquake-resistant wall described in claim 1 comprises a plurality of reinforced concrete slabs arranged in a column-beam structure with gaps in the beam length direction, with upper ends connected to the upper beams and lower ends connected to the lower beams or foundations, and an outer shell surrounding the outer surfaces of each of the plurality of reinforced concrete slabs and made of a hydraulic material having a lower strength than the concrete of the reinforced concrete slabs.

In the earthquake-resistant wall of claim 1, when an earthquake force acts on the column-beam frame, a shear force acts on the earthquake-resistant wall, causing the earthquake-resistant wall to undergo shear deformation.
In the case of small earthquake forces, the reinforced concrete slab and the outer shell undergo shear deformation and are able to withstand the earthquake forces.

When the seismic force becomes even stronger, the outer shell is destroyed in shear, and the reinforced concrete slabs arranged at intervals along the length of the beam undergo bending deformation, forming ductile walls that absorb the seismic energy.

The earthquake-resistant wall construction method described in claim 2 includes an outer shell forming process in which a hydraulic material is discharged from a nozzle of a 3D printer to form an outer shell having a plurality of hollow portions in the beam length direction that surround the insert bars provided in the lower structural member; a reinforcing bar arrangement process in which wall reinforcing bars are inserted into the hollow portions of the outer shell to form lap joints with the insert bars; a concrete pouring process in which concrete having a strength greater than the hydraulic material is poured into the hollow portions of the outer shell to form a reinforced concrete slab; and a frame construction process in which column members are constructed on both sides of the outer shell and beam members are constructed on the upper portions of the outer shell and the reinforced concrete slab to be erected on the column members.

In the earthquake-resistant wall construction method described in claim 2, in the shell formation process, a hydraulic material is ejected from the nozzle of a 3D printer to form an outer shell having multiple hollows in the beam length direction that surround the insert bars installed in the lower structural member.

In the reinforcement process, wall rebars are inserted into the hollow space of the outer shell, and lap joints are formed with the rebars.

In the concrete pouring process, concrete, which is stronger than hydraulic materials, is poured into the hollow space of the outer shell to form a reinforced concrete slab.

In the frame construction process, column members are constructed on both sides of the outer shell, and beam members are constructed on top of the outer shell and the reinforced concrete slab to be erected on the column members.

By going through the above steps, a seismic wall can be constructed within the column-beam structure.
The outer shell of the earthquake-resistant wall serves as a substitute for formwork when forming reinforced concrete slabs, eliminating the need for formwork construction that was previously required when forming conventional earthquake-resistant walls.
In addition, since the spaces between adjacent hollow sections are gaps in the reinforced concrete slabs, construction is easier than with conventional ductile walls in which slits are formed in the seismic wall to ensure deformation performance.
Furthermore, by using a 3D printer, it is possible to form the outer shell in a variety of shapes at the construction site.

The invention described in claim 3 is the earthquake-resistant wall construction method described in claim 2, which includes a horizontal reinforcing bar arrangement process in which the hydraulic material is discharged from the nozzle and layered while arranging horizontal bars to be lap-spliced with the adjacent wall reinforcing bars.

In the earthquake-resistant wall construction method according to claim 3, horizontal reinforcement is arranged in the horizontal reinforcement arrangement step.
In the earthquake-resistant wall construction method described in claim 3, the strength of the earthquake-resistant wall can be increased by lap-splicing adjacent horizontal bars and wall reinforcing bars.

As explained above, the earthquake-resistant wall of the present invention achieves high durability against earthquake forces by adding the durability of hydraulic materials.

In addition, the earthquake-resistant wall construction method of the present invention makes it easy to construct earthquake-resistant walls that are highly durable against earthquake forces.

FIG. 1A is a front view showing a column-beam structure on which an earthquake-resistant wall according to one embodiment of the present invention is constructed, and FIG. 1B is a plan view showing the column-beam structure on which the earthquake-resistant wall shown in FIG. 1A is constructed. FIG. 11 is a perspective view showing the periphery of the outer shell, illustrating the process of forming the outer shell by ejecting mortar from a nozzle of a 3D printer. 3(B) is a front view showing the outer shell of the earthquake-resistant wall in the process of being formed, and FIG. 3(A) is a plan view showing the outer shell in the process of being formed. 4(A) is a front view showing a seismic wall in the process of being constructed, illustrating the process of inserting wall reinforcing bars inside the outer shell, and FIG. 4(B) is a plan view showing the seismic wall in the process of being constructed shown in FIG. 4(A). 5(A) is a front view showing the earthquake-resistant wall, and FIG. 5(B) is a plan view showing the earthquake-resistant wall shown in FIG. 5(A). 1A is a plan view showing a conventional earthquake-resistant wall, and FIG. 1B is a graph showing the relationship between the horizontal shear deformation amount along the beam length direction of the earthquake-resistant wall and the load acting on the earthquake-resistant wall. FIG. 11 is a plan view showing a seismic wall according to another embodiment. FIG. 11 is a plan view, partly in section, showing a seismic wall according to still another embodiment. 13 is a plan view of the outer shell illustrating a method of constructing the outer shell according to another embodiment. FIG.

A seismic wall 10 according to one embodiment of the present invention and a construction method thereof will be described with reference to Figs.
As shown in FIG. 1, a seismic wall 10 of this embodiment is provided on the side surface of a column-beam frame 14 of a structure 12 such as a building, for example.

As shown in FIG. 1, the column-beam structure 14 of this embodiment is, as an example, a reinforced concrete structure, and is formed of columns 16 and beams 18 that span the columns 16. In this embodiment, the beams 18 on the upper and lower floors may be referred to as upper beams 18A and lower beams 18B, respectively.

The earthquake-resistant wall 10 constructed on the column-beam structure 14 is composed of multiple reinforced concrete slabs 22, each rectangular in elevation, arranged along the beam length direction.

(Structure of earthquake-resistant wall plate)
The outside of the reinforced concrete slab 22 is covered with an outer shell 24 made of, for example, mortar, a hydraulic material having lower strength than concrete, and the gaps between the reinforced concrete slabs 22 are filled with the outer shell 24.

The reinforced concrete slab 22 has wall reinforcing bars 28, consisting of multiple vertical bars 28A and hoop bars 28B, embedded inside the concrete 26.

The insert bars 30 protrude from the top surface of the lower beam 18B, and are lap-spliced with the vertical bars 28A of the reinforced concrete slab 22. This joins the reinforced concrete slab 22 to the lower beam 18B, and rigidly joins the lower part of the earthquake-resistant wall 10 to the lower beam 18B.

The upper end of the vertical bar 28A of the reinforced concrete slab 22 protrudes above the upper end of the reinforced concrete slab 22, and the protruding portion is lap-spliced with the beam reinforcing bar 32 of the upper beam 18A. This joins the reinforced concrete slab 22 and the upper beam 18A, and rigidly joins the upper part of the earthquake-resistant wall 10 and the upper beam 18A.

The reinforced concrete slab 22 and the column 16 are not rigidly joined, and only the widthwise side of the outer shell 24 of the earthquake-resistant wall 10 contacts the column 16.

(Seismic wall construction method)
The process of constructing the earthquake-resistant wall 10 of this embodiment will be described below.

(Shell forming process)
As shown in FIG. 2, as an example, the outer shell 24 is formed on the upper surface of the lower beam 18B to the right of the planned formation portion 16A of the pillar 16 on the left side of the drawing using a 3D printer 34.

The nozzle 34A of the 3D printer 34 is movable in three dimensions (X, Y, and Z directions in FIG. 2. As an example, the X direction is the beam length direction, the Y direction is the horizontal direction perpendicular to the X direction, and the Z direction is the vertical direction), and mortar 36 is ejected from the tip as a hydraulic material with layerable hardening properties.

By moving nozzle 34A horizontally in a rectangular shape (X direction, Y direction) while discharging mortar 36, a rectangular frame 38 made of mortar 36 can be formed. After forming the first layer of frame 38, a second layer of frame 38 is formed on top of the first layer of frame 38 in the same manner, and the frame parts 38 are stacked in sequence up to a predetermined height.

Now, before the mortar 36 of the completed lower frame 38 completely hardens, mortar 36 is dispensed above it to form the upper frame 38, and the mortar 36 of the lower frame 38 and the mortar 36 of the upper frame 38 are fused together and joined. Therefore, when the mortar 36 of the lower frame 38 and the mortar 36 of the upper frame 38 harden, the mortar 36 of the lower frame 38 and the mortar 36 of the upper frame 38 become integrated.

In addition, admixtures are mixed into the mortar 36 to adjust the workability and setting speed so that the frame sections 38 can be stacked in a short time, in other words, to prevent the lower frame section 38 from being crushed and deformed.

After the frame sections 38 are stacked up to a predetermined height to form a part of the first outer shell 24, the second outer shell 24 is formed in the same manner on the right side of the first outer shell 24, and thereafter, this process is repeated to form successive outer shells 24 until the planned width of the earthquake-resistant wall 10 is reached (see FIG. 3).
Through the above steps, a formwork for a reinforced concrete slab of mortar 36 is formed.

In this embodiment, the next adjacent outer shell 24 is formed so as to be in contact with the previously formed outer shell 24. As an example, after the mortar 36 of the previously formed outer shell 24 hardens, mortar 36 is ejected from nozzle 34A to form the frame portion 38 of the next adjacent outer shell 24.

In this embodiment, the mortar 36 of one adjacent outer shell 24 and the mortar 36 of the other outer shell 24 are prevented from fusing together and becoming one with each other. When the outer shells 24 are formed from mortar 36 in this manner, when a shear force that shifts in the vertical direction (Z direction) acts between one outer shell 24 and the other outer shell 24 adjacent thereto, a crack is generated at the boundary portion where the mortar 36 of one outer shell 24 and the mortar 36 of the other outer shell 24 meet, and the mortar 36 of one outer shell 24 and the mortar 36 of the other outer shell 24 can be separated (peeled off) at the boundary portion.

(2) Reinforcement process After forming the multiple outer shells 24 as described above, as shown in Fig. 4, wall reinforcing bars 28 are inserted from above into the interior of each outer shell 24. As a result, as shown in Fig. 1, the insert bars 29 protruding from the upper surface of the lower beam 18B and the vertical bars 28A of the wall reinforcing bars 28 are adjacent to each other to form lap joints.

(3) Concrete Pouring Process After inserting the wall reinforcing bars 28 into each outer shell 24, concrete is poured inside the outer shell 24 and allowed to harden (see FIG. 5). As a result, a reinforced concrete slab 22 made of reinforced concrete is formed inside the outer shell 24 made of mortar, and the lower part of the reinforced concrete slab 22 is rigidly joined to the lower beam 18B. As a result, the seismic wall 10 including the outer shell 24 and the reinforced concrete slab 22 is formed on the upper surface of the lower beam 18B.

(4) Frame Construction Process After the earthquake-resistant wall 10 is completed, a formwork (not shown) is assembled, reinforcement is placed within the formwork, and concrete (not shown) is poured to form the columns 16 and upper beams 18A so as to be in contact with the earthquake-resistant wall 10.
As a result of the above, the upper parts of the vertical bars 28A of the reinforced concrete slab 22 are fixed to the concrete of the upper beam 18A, and the earthquake-resistant wall 10 is constructed inside the column-beam structure 14.

(Action, Effect)
Next, the operation and effects of the earthquake-resistant wall 10 and the earthquake-resistant wall construction method of this embodiment will be described.
As an example, as shown in FIG. 1, a case where an upper beam 18A is displaced relative to a lower beam 18B in the direction of arrow A due to an earthquake force (inter-story displacement) will be described.
When the earthquake force is small, the earthquake-resistant wall 10, that is, the earthquake-resistant wall 10 consisting of the multiple reinforced concrete slabs 22 and the outer shell 24, undergoes shear deformation to bear the earthquake force.

If an even larger horizontal force (seismic force) is applied, a shear force (arrow F in Figure 1) acts between one adjacent reinforced concrete slab 22 and the other adjacent reinforced concrete slab 22. If the seismic force is small, even if a shear force acts in the vertical direction, no cracks (peeling) will occur at the boundary between the outer shell 24 of one adjacent reinforced concrete slab 22 and the outer shell 24 of the other adjacent reinforced concrete slab 22, and they will resist the shear force as one.

The graph shown in Fig. 6(B) shows, as an example, a schematic relationship between the amount of displacement (horizontal axis) and the load acting on the shear wall (vertical axis) when the lower part of the shear wall is fixed and a load is applied to the upper part of the shear wall in the beam length direction to displace it. Graph line A shown in Fig. 6(B) shows the relationship between the amount of displacement and the load of the shear wall of the embodiment, and graph line B shows the relationship between the amount of displacement and the load of the shear wall of the comparative example formed of a single reinforced concrete slab as shown in Fig. 6(A).
The comparative example earthquake-resistant wall is an earthquake-resistant wall in which wall reinforcement bars consisting of multiple vertical bars and multiple horizontal bars extending continuously from one side of the width of the earthquake-resistant wall to the other side are arranged inside the concrete, and the amount of reinforcement bars per unit area is equivalent to that of the earthquake-resistant wall of the example, and the wall thickness is also the same.

When the seismic force is relatively small and the amount of displacement is relatively small, the load increases in proportion to the amount of displacement, as shown in part a of graph line A, and the slope of part a is relatively steep.

When the seismic force becomes large, the displacement increases, the outer shell breaks, and only the reinforced concrete slab 22 bears the shear force, the relationship between the displacement and the load becomes like part b of graph line A, the deformation transitions to bending deformation, the slope becomes gentler, and plastic deformation does not occur.

When the amount of displacement becomes even larger, as shown by part c of graph line A, the shear wall 10 undergoes plastic deformation and the vertical reinforcement 28A of the reinforced concrete slab 22 yields, but maintains its strength.

On the other hand, as shown by graph line B, the comparative example earthquake-resistant wall 100 undergoes shear failure when the reinforced concrete slab 22 of the example undergoes bending deformation, causing a sudden drop in strength and failing to function as an earthquake-resistant wall 100.

In this way, even if the displacement of the shear deformation in the beam length direction becomes somewhat larger than that of the shear wall 100 of the comparative example, the shear wall 10 of this embodiment transitions to bending deformation, maintaining the functionality of the shear wall 10 and being able to absorb earthquake energy, and is therefore prevented from suddenly collapsing in a major earthquake.

In addition, according to the construction method for the earthquake-resistant wall 10 of this embodiment, the outer shell 24, which also serves as a formwork, is formed using a 3D printer 34, so that no formwork is required to form the earthquake-resistant wall 10 (reinforced concrete slab 22), making it easier to construct the earthquake-resistant wall 10.

[Other embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be implemented in various modified forms without departing from the spirit and scope of the present invention.

In the above embodiment, the earthquake-resistant walls 10, columns 16, upper beams 18A, and lower beams 18B were constructed on-site, but, for example, as shown in (1) to (3) below, any of the columns 16, upper beams 18A, and lower beams 18B can be precast, and the outer shell 24 can be formed using a 3D printer 34 in a factory or the like other than the construction site.

(1) Method 1
Pillars: Precast Beams: On-site construction Earthquake-resistant walls: Outer shell formed on-site with a 3D printer

(2) Method 2
Pillars: Precast Beams: On-site construction Earthquake-resistant walls: Outer shell formed in factory using 3D printer

(3) Method 3
Column: Precast beam: Precast earthquake-resistant wall: The shell is formed in the factory using a 3D printer. When the shell is formed in the factory using a 3D printer and the earthquake-resistant wall is constructed on-site, mortar is filled between the components on-site to connect the components with mortar. In other words, it is preferable not to leave gaps between the components, as this would reduce earthquake resistance.

In the above embodiment, the thickness of the reinforced concrete slabs 22 was constant, but as shown in FIG. 7, chamfers 40 may be formed at the corners as necessary to reduce the contact area with the short side that comes into contact with the other adjacent reinforced concrete slab 22. This makes it easier to separate one adjacent reinforced concrete slab 22 from the other adjacent reinforced concrete slab 22.

8, horizontal bars 42 penetrating the wall portion on the short side of the outer shell 24 of one adjacent reinforced concrete slab 22 and the wall portion on the short side of the outer shell 24 of the other adjacent reinforced concrete slab 22 may be arranged at appropriate intervals in the vertical direction of the reinforced concrete slab 22. The horizontal bars 42 are arranged in positions where they do not interfere with the wall reinforcing bars 28 when they are inserted. The ends of the horizontal bars 42 are overlapped with the wall reinforcing bars 28 to form lap joints, and the horizontal bars 42 are fixed to the concrete of the reinforced concrete slab 22.
By adding horizontal bars 42 in this manner, adjacent reinforced concrete slabs 22 can be connected to each other by the horizontal bars 42, thereby increasing the strength of the earthquake-resistant wall 10.

In the above embodiment, the earthquake-resistant wall 10 is formed on the lower beam 18B, but the earthquake-resistant wall 10 can also be formed on the foundation beam.

In the above embodiment, the outer shell 24 is formed from mortar, but the outer shell 24 may be made of a material other than mortar, such as a cement base or grout, as long as it is a hydraulic material (a material that hardens when exposed to moisture) that has a lower strength than concrete.

In the above embodiment, the mortar of the outer shell 24 of one adjacent reinforced concrete slab 22 and the mortar of the outer shell 24 of the other adjacent reinforced concrete slab 22 are not mixed together and integrated, but the present invention is not limited to this. The mortar of the outer shell 24 of one adjacent reinforced concrete slab 22 and the mortar of the outer shell 24 of the other adjacent reinforced concrete slab 22 may be mixed together and integrated. In this case, a first layer of outer shell 24 may be formed from one column 16 to the other column 16, and the second and subsequent layers of outer shell 24 may be stacked on top of it in sequence, and the manner in which the nozzle 34A is moved to form the outer shell 24 is not limited to that of the above embodiment.

9A and 9B show an example in which the outer shell 24 is formed continuously from one pillar 16 to the other pillar 16.
As shown by the arrow in the drawing, the nozzle 34A is continuously moved from a mortar discharge start position 24S to a mortar discharge end position 24E, thereby forming a first outer shell 24 that is continuous from one pillar 16 to the other pillar 16. Then, the second and subsequent outer shells 24 can be successively formed on top of that in the same manner.
In the example shown in Figure 9 (B), at the intersection between the forward path (right-pointing arrow) and the return path (left-pointing arrow), the ejection of mortar on either the forward path or the return path is temporarily stopped at the intersection point so that the mortar on the forward path does not overlap with the mortar on the return path.

10 Earthquake-resistant wall 14 Column-beam structure 18A Upper beam 18B Lower beam 22 Reinforced concrete slab 24 Outer shell 34 3D printer 34A Nozzle 42 Horizontal reinforcement

Claims (3)

A plurality of reinforced concrete slabs are arranged in the column-beam structure with gaps in the beam length direction, and the upper end portions are connected to the upper beams and the lower end portions are connected to the lower beams or foundations;
an outer shell surrounding each of the outer surfaces of the plurality of reinforced concrete slabs and made of a hydraulic material having a strength lower than that of the concrete of the reinforced concrete slabs;
A seismic wall having the above structure. A shell forming process in which a hydraulic material is discharged from a nozzle of a 3D printer to form an outer shell having a plurality of hollow portions in the beam length direction surrounding the insert bars provided in the lower structural member;
A reinforcing bar arrangement process in which a wall reinforcing bar is inserted into the hollow portion of the outer shell to form a lap joint with the reinforcing bar;
a concrete pouring step of pouring concrete having a strength greater than that of the hydraulic material into the hollow portion of the shell to form a reinforced concrete slab;
A frame construction process of constructing column members on both sides of the outer shell and constructing beam members to be installed on the column members on the upper part of the outer shell and the reinforced concrete slab;
A method for constructing earthquake-resistant walls. A horizontal reinforcing bar arrangement process is provided in which the hydraulic material is discharged from the nozzle to laminate the hydraulic material while arranging horizontal reinforcing bars to be lap-spliced with the adjacent wall reinforcing bars.
The earthquake-resistant wall construction method according to claim 2.