JP6649069B2 - Seismic reinforcement structure - Google Patents

Description

  The present invention relates to a seismic retrofit structure for reinforcing a structure having a rigid frame structure.

2. Description of the Related Art In recent years, seismic reinforcement work for viaducts supporting tracks and roads has been promoted in various places. As a method of seismic reinforcement of structures with a ramen structure (hereinafter referred to as ramen structures) such as viaducts, the columns are surrounded by steel plates, and the gap between the columns and the steel plate is filled with mortar and solidified to deform There is known a steel sheet winding method for improving performance.
However, in order to reinforce the rigid frame structure by this method, it is necessary to attach steel plates to all columns in principle. Therefore, under the bridge girder, buildings such as station buildings and commercial facilities, or various facilities necessary for the operation of trains (hereinafter referred to as obstacles) are provided, and pillars are in contact with obstacles or pass through obstacles. In such a case, most or all of these obstacles must be removed in order to secure a work space for the construction, which has caused an increase in cost and a prolonged construction. In addition, the removed obstacles often need to be in the same place even after the seismic retrofitting, so that cost and time are required to restore the obstacles.

  Therefore, recently, a brace-type damper configured to be expandable and contractible is arranged in a mountain shape between the lower ends of two adjacent columns constituting the ramen structure and an intermediate portion of a beam straddling both columns, or A seismic retrofitting method has been proposed in which a rocking energy is absorbed by expansion and contraction of a rod-like member by disposing along a diagonal of a rectangular opening formed by a foundation, a column, and a beam (for example, Patent Documents). 1). According to this method, the structure can be provided with the same level of seismic resistance as the steel plate winding method with the number of braces less than the steel plate, without removing any obstacles under the bridge girder at all. Alternatively, the necessary seismic reinforcement can be provided by removing only a little.

JP 2003-066424 A

However, when the ramen structure reinforced with the above-mentioned brace is shaken and slightly deformed, it receives stress from the brace at the joint between the ramen structure and the brace, especially near the joint between the column and the foundation. Become. If such a force is applied before the structure is plastically deformed with small shaking, there is a possibility that the base is excessively applied and the foundation is damaged. Therefore, in the case of seismic reinforcement with braces, it is usually necessary to reinforce the rigidity of the foundation in order to prevent the foundation from being damaged by stress from the brace.
In other words, the conventional seismic retrofitting method using braces can save the cost and time required for removing and restoring obstacles, but the cost and time required to reinforce the foundations. It was difficult to suppress the cost increase and the prolonged construction.

  An object of the present invention is to provide a seismic retrofit structure that can reduce the construction cost and improve the seismic performance of a ramen structure.

To achieve the above object, the present invention provides
It is installed on a structure having a rigid frame structure including a plurality of columns erected at predetermined intervals and a beam provided to connect the upper portion of each column, thereby improving the earthquake resistance of the structure. An earthquake-resistant reinforced structure,
A first reinforced concrete member provided in a horizontal direction so as to connect a lower part of any adjacent column among the plurality of columns of the structure;
A second reinforced concrete member disposed above the first reinforced concrete member and provided in a horizontal direction so as to connect the adjacent columns;
A pair of third reinforced concrete members that connect an end of the first reinforced concrete member and an end of the second reinforced concrete member and are provided in a vertical direction along the column;
When the upper part of the structure is displaced in the horizontal direction with respect to the lower part, the third reinforced concrete member and the third reinforced concrete member are arranged so as not to contact the adjacent columns. There is a gap in the
A joint is formed between the first reinforced concrete member and the third reinforced concrete member, and between the second reinforced concrete member and the third reinforced concrete member, and each reinforced concrete member is separately formed. So that they can behave individually .

In this seismic retrofitting structure, a gap is provided so that the third reinforced concrete member provided vertically along the column of the ramen structure does not contact the column. It is hard to be destroyed. If there is no gap between the third reinforced concrete member and the column and there is no gap, the column will be apparently thick and the column will be relatively short, and the shear span will be short and shear failure will easily occur, which is preferable. Absent.
Further, for example, if a round steel bar is used for the reinforcing bar of each reinforced concrete member and a gap is provided between the third reinforced concrete member and the column, the seismic retrofitting structure locks and absorbs the energy of the seismic motion. In this case, the third reinforced concrete member and the column do not come into contact with each other and do not hinder the rocking, so that the energy of the shaking can be suitably absorbed.
The seismic retrofit structure has a relatively simple structure made of a reinforced concrete member, and at least one seismic retrofit structure is provided between any adjacent columns of the plurality of columns of the ramen structure. By installing, it is possible to achieve seismic reinforcement of the entire ramen structure.
In addition, if a joint is formed between the reinforced concrete members of the seismic reinforced structure, the joint is opened when an earthquake occurs, whereby the seismic reinforced structure is rocked and the energy of shaking can be absorbed.
That is, with this earthquake-resistant reinforced structure, the construction cost can be suppressed and the earthquake-resistant performance of the ramen structure can be improved.

Also, preferably,
At the joint, the grease applied to the joint is interposed.
By interposing a grease agent at the joint between the reinforced concrete members of the aseismic reinforcement structure, each of the reinforced concrete members easily behaves individually without the reinforced concrete members sticking to each other. This becomes remarkable when, for example, a round steel bar is used as the reinforcing bar of each reinforced concrete member.
That is, by interposing the grease agent at the joint, the joint between the reinforced concrete members is easily opened, and the earthquake-resistant reinforcing structure is easily rocked when an earthquake occurs, so that the energy of the shaking can be absorbed.

Also, preferably,
As the reinforcing steel inside the first reinforced concrete member, the second reinforced concrete member, and the third reinforced concrete member, a steel material having no uneven surface is used.
If a steel material such as a round steel bar with no irregularities on the surface is used as the reinforcing bar for each reinforced concrete member of the seismic retrofit structure, the concrete and the rebar are easily peeled off and the adhesion is easily cut off, and the seismic retrofit structure undergoes plastic deformation When the structure having the rigid frame structure starts to be plastically deformed, the seismic retrofitting structure can be plastically deformed to absorb shaking energy.
If the adhesion between the concrete and the reinforcing bar is easily broken, the seismic strengthening structure can be suitably rocked and can absorb the energy of shaking.

  ADVANTAGE OF THE INVENTION According to this invention, the construction cost can be suppressed and the seismic performance of a ramen structure can be improved.

It is the side view (a) which shows the earthquake-resistant reinforcement structure of this embodiment, and the top view (b) which looked at the bb line of Drawing 1 (a) in section. It is an explanatory view showing an example of an arrangement pattern of a aseismic reinforcement structure. It is an explanatory view showing an example of an arrangement pattern of a aseismic reinforcement structure. It is explanatory drawing (a) (b) (c) (d) of the test body of the earthquake-resistant reinforcement structure used for the static positive / negative alternating load test. It is a graph which shows the result of a static positive / negative alternating load test with respect to the test body of an earthquake-resistant reinforcement structure.

  Hereinafter, an embodiment of an earthquake-resistant reinforcement structure according to the present invention will be described in detail with reference to the drawings. However, the embodiments described below are provided with various technically preferable limits for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

First, a schematic configuration of a structure in which the earthquake-resistant reinforcement structure 50 of the present embodiment is installed will be described by taking a viaduct as an example. FIGS. 1A and 1B show a viaduct 100 which is a ramen structure.
The viaduct 100 in the present embodiment is constructed by, for example, arranging a plurality of viaduct blocks 100a (hereinafter, blocks 100a) in the bridge axis direction, and installing and connecting a beam 100b therebetween.
Each block 100a includes a plurality of foundations 10 provided in the ground, pillars 20 provided on each foundation 10, beams 30 provided on the plurality of pillars 20, and the like. .

The foundation 10 includes a plurality of piles 101 driven into the ground and a footing 102 provided on the plurality of piles 101.
The pillar 20 is erected on each footing 102. The plurality of pillars 20 are arranged in a matrix in which x (x ≧ 2) in the bridge axis direction of the viaduct 100 and y (y ≧ 2) in the direction perpendicular to the bridge axis for one block 100a. FIG. 1 illustrates a case where 4 × 4 = 16 pillars 20 are present in one block.
The beam 30 is provided on the plurality of columns 20 in a lattice shape so as to connect the upper portions of the columns 20.
An earthquake-resistant reinforcing structure 50 is installed between any adjacent columns 20 in the viaduct 100.

As shown in FIGS. 1A and 1B, the seismic retrofit structure 50 is provided in a horizontal direction so as to connect a lower part of any adjacent pillar 20 among a plurality of pillars 20 constituting the viaduct 100. A first reinforced concrete member 51, a second reinforced concrete member 52 disposed above the first reinforced concrete member 51 and provided in a horizontal direction so as to connect adjacent columns 20, an end of the first reinforced concrete member 51 and a second reinforced concrete member 51. And a pair of third reinforced concrete members 53 that connect the ends of the two reinforced concrete members 52 and are provided vertically along the columns 20.
Both ends of the first reinforced concrete member 51 and the second reinforced concrete member 52 are connected to the columns 20 by anchors 54, respectively.
A gap 55 is provided between the third reinforced concrete member 53 and the column 20. The gap 55 is provided so that the third reinforced concrete member 53 does not come into contact with the column 20 when the upper portion of the viaduct 100 having a rigid frame structure is displaced horizontally with respect to the lower portion. In this embodiment, the width of the gap 55 is designed to be 20 mm.

A joint 56 is formed between the first reinforced concrete member 51 and the third reinforced concrete member 53 and between the second reinforced concrete member 52 and the third reinforced concrete member 53.
The joint 56 is an embodiment of a concrete joint formed at the joint between the pre-cast concrete and the post-cast concrete.
Specifically, a pre-cast concrete is cast using a mold or the like, and the pre-cast concrete is hardened to form the first reinforced concrete member 51. Next, a formwork for the third reinforced concrete member 53 is assembled, a post-cast concrete is poured into the formwork, and then the cast concrete is hardened to form the third reinforced concrete member 53, whereby the first reinforced concrete member 51 is formed. A joint 56 can be formed between the third reinforcing member 53 and the third reinforced concrete member 53.
Similarly, after the third reinforced concrete member 53 is formed, a formwork for the second reinforced concrete member 52 is assembled, post-cast concrete is poured into the formwork, and then the cast concrete is hardened to form a second reinforced concrete member. By forming 52, it is possible to form a joint 56 between the third reinforced concrete member 53 and the second reinforced concrete member 52. At this time, the second reinforced concrete member 52 is formed by treating the already hardened third reinforced concrete member 53 as pre-cast concrete.
In particular, after the pre-cast concrete has hardened, the grease is applied to the joints 56 between the reinforced concrete members by applying the grease to the joints with the post-cast concrete. By interposing a grease agent in the joint 56, each reinforced concrete member can behave separately and individually without sticking.
Note that a round steel bar, which is a steel material having no uneven surface, is used for the reinforcing bar 5 inside the first reinforced concrete member 51, the second reinforced concrete member 52, and the third reinforced concrete member 53. However, in the embodiment, it is not necessary that all the reinforcing bars 5 are round steel bars. For example, as a result of the rocking of the seismic retrofitting structure 50, only the reinforcing bar at a location where damage occurs in the structure or the reinforcing bar penetrating the joint 56 is round steel, and the other reinforcing bars are irregularly shaped reinforcing bars. Is also good.
In the present embodiment, a round steel bar is also used as the reinforcing bar of the viaduct 100 (block 100a).

At least one or more quake-resistant reinforcement structures 50 are installed in each block 100a. As described above, since the adjacent columns 20 are arranged in the bridge axis direction or in the direction perpendicular to the bridge axis, the seismic retrofit structure 50 is, as viewed from above, as shown in FIG. 20 and between the pillars 20 adjacent to the pillar 20 in the bridge axis direction, or between a certain pillar 20 and the pillar 20 adjacent to the pillar 20 in the direction perpendicular to the bridge axis. Particularly, in the block 100a (viaduct 100), the seismic retrofit structure 50 is installed between the columns 20 in the space where the obstacle A is not provided.
Then, by installing the number of seismic retrofitting structures 50 according to the structure of the block 100a to be reinforced and the state of the ground where the block 100a is located, the entire block 100a can be provided with the required earthquake resistance. .
For example, as shown in FIG. 1B, in the present embodiment, two seismic retrofitting structures 50 installed between columns 20 adjacent in the bridge axis direction and columns 20 adjacent in the direction perpendicular to the bridge axis. The seismic reinforcement of the block 100a is achieved by the two seismic reinforcement structures 50 installed.
Here, the four seismic retrofitting structures 50 are arranged so as to surround a part of the space below the block 100a so as to have a rectangular shape in plan view.

The arrangement pattern of the four earthquake-resistant reinforcement structures 50 is not limited to this, and is arbitrary.
The plurality of seismic retrofit structures 50 may be disposed in a well-balanced manner from the center of the weight of the block 100a and the rigidity of the hardness, and may be disposed symmetrically as the entire structure of the block 100a. For example, it is preferable that the plurality of seismic retrofitting structures 50 installed in the block 100a are arranged in a pattern in which the numbers are symmetrically the same as the entire system of the structure.
Specifically, the arrangement pattern of the four earthquake-resistant reinforcement structures 50 may be the pattern shown in FIG. 2 or the pattern shown in FIG.

Next, the operation of the seismic retrofit structure 50 installed in the viaduct 100 during an earthquake will be described.
When an earthquake motion acts on the viaduct 100, the beam 30 is relatively displaced in the horizontal direction with respect to the ground, and each column 20 is inclined together with the beam 30 in the direction of the displacement.

While the displacement amount of the column 20 and the beam 30 is small, the second reinforced concrete member 52 of the seismic strengthening structure 50 is displaced horizontally with respect to the first reinforced concrete member 51 with the inclination of the column 20, and the third reinforced concrete member is moved. The member 53 is slightly inclined in the direction of displacement of the second reinforced concrete member 52. At this time, the joint 56 between the reinforced concrete members is opened, and the third reinforced concrete member 53 is slightly lifted from the first reinforced concrete member 51, and the second reinforced concrete member 52 is slightly lifted from the third reinforced concrete member 53. Rocking occurs in the seismic retrofit structure 50 in such a manner that the rising of the reinforced concrete member is repeated right and left according to the seismic motion.
When rocking occurs in the seismic retrofit structure 50, the energy of the shaking can be absorbed.

  Further, since the first reinforced concrete member 51, the second reinforced concrete member 52, and the third reinforced concrete member 53 use round steel bars as the reinforcing bars 5, when rocking occurs in the earthquake-resistant reinforcing structure 50, the concrete and the reinforcing bars are used. 5 are easily peeled off and slippery with each other, so that the earthquake-resistant reinforcing structure 50 can be properly locked and can absorb the energy of shaking.

Further, when the displacement amount of the column 20 or the beam 30 increases and the joint portion of each part of the viaduct 100 (block 100a) starts to be plastically deformed, the seismic retrofitting structure 50 is plastically deformed to reduce the energy of shaking. Becomes absorbed.
Since the gap 55 is provided between the third reinforced concrete member 53 and the column 20, the third reinforced concrete member is used when rocking occurs in the aseismic reinforcement structure 50 or when the aseismic reinforcement structure 50 is plastically deformed. The third reinforced concrete member 53 and the column 20 are separated from each other and behave individually.

Next, performance test results of the seismic retrofit structure 50 will be described.
In the performance test, three columns 120 erected on a reinforced concrete block 110 corresponding to the foundation 10 as a test structure simulating the viaduct 100 (block 100a), as shown in FIG. A test structure 1 having a reinforced concrete block 130 corresponding to the beam 30 joined so as to connect the upper portions of the three columns 120 was used. As a reinforcing bar of this test structure 1, a round steel bar is used.
Then, a single unit of the test structure 1 which is not reinforced is referred to as a test piece No. 1 (see FIG. 4A).

Further, a reinforced concrete body simulating the first reinforced concrete member 51, the second reinforced concrete member 52, and the third reinforced concrete member 53 is formed between the one pillar 120 of the test structure 1 so as not to form a joint. A structure in which a portion corresponding to the third reinforced concrete member 53 was brought into close contact with the column 120 of the test structure 1 was installed as a reinforcing structure 502, and this was set as a test sample No. 2 (see FIG. 4B).
Note that a grease was applied to the column 120 of the test structure 1 so that the column 120 of the test structure 1 and the reinforcing structure 502 were not integrated.
Further, a rubber plate G was interposed between the reinforcing structure 502 and the reinforced concrete block 110 as a ground simulation material.

Further, a reinforced concrete body simulating the first reinforced concrete member 51, the second reinforced concrete member 52, and the third reinforced concrete member 53 is formed between one pillar 120 of the test structure 1 so as not to form a joint. Is installed as a reinforcing structure 503, and this is used as a test piece No. 3 (see FIG. 4C).
The gap between the portion corresponding to the third reinforced concrete member 53 and the column 120 of the test structure 1 was set to 20 mm.
Further, a rubber plate G was interposed between the reinforcing structure 503 and the reinforced concrete block 110 as a ground simulation material.

Then, a reinforced concrete body corresponding to the first reinforced concrete member 51, the second reinforced concrete member 52, and the third reinforced concrete member 53 is interposed between the one pillar 120 of the test structure 1 with a grease agent interposed at the joint 56. Specimen No. with the reinforcing structure 504 made in the test piece No. 4 (see FIG. 4D). The gap between the portion corresponding to the third reinforced concrete member 53 and the column 120 of the test structure 1 was set to 20 mm.
That is, the specimen No. The fourth reinforcement structure 504 corresponds to the earthquake-resistant reinforcement structure 50 of the present embodiment.
Note that a rubber plate G was interposed between the reinforcing structure 504 and the reinforced concrete block 110 as a ground simulation material.

The test piece No. 1 to Specimen No. 4 was subjected to a static positive / negative alternating loading test to evaluate its seismic performance.
In the static positive / negative alternating load test, a load of 1 [N / mm ² ] per cross-sectional area of the column 120 was applied to the reinforced concrete block 130 of each test piece in the vertical direction, and the reinforced concrete block 130 was removed. The load required when displacing in the horizontal direction was measured. FIG. 5 shows the measurement results.
In the graph shown in FIG. 1 is a load-displacement curve, and L2 is a specimen No. 2 is a load-displacement curve, and L3 is the specimen No. No. 3, the load-displacement curve, L4 is the specimen No. 4 is a load-displacement curve of FIG.

In the graph shown in FIG. Specimen no. Since the load-displacement curve of No. 2 is generally on the high load side in the region where the displacement is larger, the test piece No. Specimen no. It can be seen that No. 2 has better seismic performance.
This is the specimen No. In No. 2, the above-described reinforcing structure 502 was provided between the columns 120 of the test structure 1.

On the other hand, in the graph shown in FIG. Specimen no. Since the load-displacement curve of No. 3 is generally on the high load side, the test piece No. 3 Specimen no. It can be seen that No. 3 has better seismic performance.
This is the specimen No. In No. 3, the above-mentioned reinforcing structure 503 was installed between the columns 120 of the test structure 1, and thus a gap was provided between the reinforcing structure 503 and the column 120 of the test structure 1. .
Specimen No. When the reinforcing structure 502 and the column 120 of the test structure 1 are in close contact with each other as in 2, the column 120 of the test structure 1 is apparently thick and relatively short, so that shear failure is reduced. It is easy to occur.
That is, the specimen No. As shown in FIG. 3, when a gap is provided between the reinforcing structure 503 and the column 120 of the test structure 1, shear fracture is less likely to occur, and the seismic performance is improved.

Further, in the graph shown in FIG. Specimen no. Since the load-displacement curve of No. 4 is generally on the high load side in the region where the displacement is larger, the test piece No. 4 Specimen no. It can be seen that No. 4 has better seismic performance.
This is the specimen No. In No. 4, the gap is provided between the reinforcing structure 504 and the column 120 of the test structure 1, and the joint 56 is provided between the reinforced concrete members of the reinforcing structure 504.
Specimen No. When the joint 56 is provided between the reinforced concrete members of the reinforcing structure 504 as in 4, the reinforcing structure 504 can be rocked and can absorb the energy of shaking.
That is, the specimen No. As shown in FIG. 4, it is understood that the rocking of the reinforcing structure 504 absorbs the energy of the shaking, thereby improving the seismic performance.
From the results of such a static positive / negative alternating loading test, the specimen No. 1 to No. 4 among the specimen Nos. 4 that the seismic performance is excellent.

As described above, as the seismic retrofit structure 50 installed in the viaduct 100 (block 100a) having the rigid frame structure, the third reinforced concrete member 53 arranged vertically along the column 20 of the viaduct 100 comes into contact with the column 20. It is preferable that a gap 55 is provided so as not to cause the gap.
If the third reinforced concrete member 53 and the column 20 are in close contact with no gap, the column 20 is apparently thick and relatively short, and shear failure is likely to occur, which is not preferable.

As the seismic retrofit structure 50 installed in the viaduct 100 (block 100a) having a rigid frame structure, a third reinforced concrete member 53 vertically disposed along the pillar 20 of the viaduct 100 and a horizontal reinforcement are provided. It is preferable that a joint 56 is formed between the first reinforced concrete member 51 and the second reinforced concrete member 52 thus formed.
If the joint 56 is provided between the reinforced concrete members, rocking occurs in the seismic retrofitting structure 50 at the time of an earthquake, so that the energy of shaking can be absorbed.
In particular, if the gap 55 is provided between the third reinforced concrete member 53 and the column 20, the seismic retrofit structure 50 is easily rocked, and the energy of the seismic motion can be suitably absorbed.

In addition, the seismic retrofit structure 50 can be reinforced by seismic reinforcement of the entire viaduct 100 consisting of a plurality of blocks 100a only by being installed between some of the columns 20 constituting each block 100a of the viaduct 100.
For this reason, even if the obstacle A is provided under the viaduct 100, if there is a space without the obstacle A, the seismic strengthening structure 50 is installed between the columns 20 of the space, and the obstacle A is The seismic retrofitting work of the viaduct 100 can be performed without any removal. Alternatively, seismic reinforcement work of the viaduct 100 can be performed by slightly removing the obstacle A to temporarily create a work space.

  In particular, when a round steel bar is used as the reinforcing bar of the viaduct 100 (block 100a), if the round steel bar is used as the reinforcing bar 5 of each reinforced concrete member of the earthquake-resistant reinforcing structure 50, the viaduct 100 and the earthquake-resistant reinforcing structure 50 are used. In this case, the behavior that the concrete and the rebar are easily peeled off and slip easily with each other is aligned, so that the energy of the shaking can be suitably absorbed, and the seismic reinforcement can be suitably performed.

As described above, the earthquake-resistant reinforcing structure 50 of the present embodiment has a relatively simple structure made of a reinforced concrete member, and is provided between any adjacent columns 20 of the plurality of columns 20 of the viaduct 100. By installing at least one earthquake-resistant reinforcement structure 50, the entire viaduct 100 can be subjected to earthquake-resistant reinforcement.
That is, with this earthquake-resistant reinforcing structure 50, the construction cost can be suppressed and the earthquake-resistant performance of the viaduct 100 can be improved.

  In the above embodiment, the case where four seismic retrofitting structures 50 are installed in one block 100a has been described as an example, but the present invention is not limited to this, and is installed in the block 100a. The number of earthquake-resistant reinforcement structures 50 to be used is arbitrary.

  In addition, it goes without saying that specific detailed structures and the like can be appropriately changed.

DESCRIPTION OF SYMBOLS 10 Foundation 20 Column 30 Beam 50 Seismic retrofitting structure 51 First reinforced concrete member 52 Second reinforced concrete member 53 Third reinforced concrete member 54 Anchor 55 Gap 56 Joint 5 Reinforcement 100 Viaduct (Ramen structure)
100a Viaduct block A Obstacle

Claims (3)

It is installed on a structure having a rigid frame structure including a plurality of columns erected at predetermined intervals and a beam provided to connect the upper portion of each column, thereby improving the earthquake resistance of the structure. An earthquake-resistant reinforced structure,
A first reinforced concrete member provided in a horizontal direction so as to connect a lower part of any adjacent column among the plurality of columns of the structure;
A second reinforced concrete member disposed above the first reinforced concrete member and provided in a horizontal direction so as to connect the adjacent columns;
A pair of third reinforced concrete members that connect an end of the first reinforced concrete member and an end of the second reinforced concrete member and are provided in a vertical direction along the column;
A gap is provided so that the pair of third reinforced concrete members do not contact the adjacent columns when the upper part of the structure is displaced horizontally with respect to the lower part ,
A joint is formed between the first reinforced concrete member and the third reinforced concrete member, and between the second reinforced concrete member and the third reinforced concrete member, and each reinforced concrete member is separately formed. A seismic retrofit structure characterized by being able to behave individually . The seismic strengthening structure according to claim 1 , wherein a grease applied to the joint is interposed at the joint .   The seismic reinforcement according to claim 1 or 2, wherein a steel material having no uneven surface is used for a reinforcing bar inside the first reinforced concrete member, the second reinforced concrete member, and the third reinforced concrete member. Structure.

Images