JPH10331436A - Earthquake-resisting reinforcing structure for beam-column in existing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce a column for an RC-constructed existing structure by a steel plate and concrete without anew installing a brace material and an earthquake-resisting wall into the existing structure while increasing the strength of beams-columns by reinforcing the end sections of beams. SOLUTION: In the reinforcing structure to a reinforced concrete-constructed existing beam-column 11, a column type steel plate 1 is divided into the plural in the vertical direction, the existing column 11 is surrounded by the column type steel plates 1 and the column type steel plates 1 are welded and joined mutually, and sections among the column type steel plates 1 and the existing column 11 are filled with fillters 9 to form a steel-plate concrete column A while the Joining sections of the steel-plate concrete column A and the existing beam 21 are unified and connected through reinforcing metal fittings D, in which rib plates 14 are fixed onto horizontal plates 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic reinforcement structure for an existing concrete building, and is applied to a building, an elevated structure such as a road and a railway.

[0002]

2. Description of the Related Art Conventionally, reinforced concrete (hereinafter referred to as R
Abbreviated as C. ) When performing seismic reinforcement for existing structures such as steel structures and steel reinforced concrete structures, reinforced concrete is usually wrapped around pillars to add concrete, or reinforced with fiber sheets or steel plates. Is going. However, the existing columns and beams were not integrally reinforced.

[0003]

In recent years, there has been an increasing demand for seismic reinforcement of existing RC structures in anticipation of a case where a larger earthquake has occurred than before. I have. For the seismic reinforcement against such a large earthquake, the above-mentioned conventional reinforcement is applied to existing RC.
When applied to a column, the column itself exhibits seismic resistance, but the beam connected to the column is usually not reinforced with seismic reinforcement integrated with the column, so the strength may be insufficient compared to the column .
Therefore, there is a possibility that the girder will crack during a large earthquake.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. Accordingly, the present invention is not to provide a new bracing material or earthquake-resistant wall in the existing structure, but to use a steel plate as a pillar of the existing RC structure. It is an object of the present invention to provide a seismic retrofitting structure for an existing building that can be reinforced by concrete and reinforced at the end of the beam to improve the strength of the beam.

[0005]

In order to achieve the above object, the present invention relates to a reinforcing structure for an existing reinforced concrete column and beam, wherein a columnar steel plate is viewed from a flat cross section. The existing column is divided into a plurality of sections in the longitudinal direction at a substantially diagonal line extending, and the existing column is surrounded by the same column type steel plate, and the column type steel plates are welded to each other, and the space between the column type steel plate and the existing column is filled. Filling the material to form a steel plate concrete pillar, and jointing the steel plate concrete pillar and the existing beam with a horizontal metal plate with a reinforcing plate fixed to a rib plate.
It is in the seismic retrofit structure of columns and beams in existing structures.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. <A> Prerequisites In the case where seismic retrofit is to be performed on existing structures assuming that a larger earthquake has occurred than before, the present invention can be implemented in a short period of time without installing new bracing materials or earthquake-resistant walls. It responds to the need to improve the necessary and sufficient seismic reinforcement structure. According to the present invention, an existing column is reinforced to form a filled steel plate concrete column, and a reinforcing metal is interposed at a joint between the concrete column and the existing beam to integrally and strongly reinforce the column. In the embodiment of the present invention, the reinforcement state of the beam end when the existing beam is connected in both directions perpendicular to each other with the filled steel plate concrete column as the center is shown in FIGS. Depending on the properties of the beam, it is of course possible to reinforce the beam in one direction or a specific beam, and the point is that the column and the beam end connected to the column are integrally and simultaneously reinforced with earthquake resistance. Is the gist.

<B> Embodiments of Column Type Steel Plates The column type steel plates 1, 2, and 3 are steel plates surrounding and reinforcing an existing column (RC column) 11, the length of which is the effective length of the column 11, for example, And the height from the upper end of the floor or the beam 21 on the floor to the lower end of the beam 22 on the upper floor. (A) The columnar steel plate 1 shown in FIG. 1 and FIG.
It is a semicircular steel plate obtained by dividing a circular steel pipe into two in the vertical direction, and is divided at a joint 4 where a diagonal line XX of the existing column 11 extends.

(B) The column-shaped steel plate 2 shown in FIG. 3 is a substantially L-shaped steel plate obtained by dividing a square steel pipe into two in the longitudinal direction of the column. This substantially L-shaped steel plate 2 is divided into two parts by a flat joint portion 5 near a corner of a square steel pipe when viewed in a plane.

(C) The column-shaped steel plate 3 shown in FIG. 4 is formed by welding two of each of the four skin plates 13 to form an L-shape and is divided into two parts. It is divided at the junction 6 where X extends.

Each of the column-shaped steel plates 1, 2, 3 has a groove for welding W-joining the steel plates to each other at two divided end faces. Further, a backing material is attached to one end of the columnar steel plate on the back surface of the groove (not shown). Further, each of the column-shaped steel plates 1, 2, and 3 is not limited to being divided into two, and may be divided into a plurality of parts, and the dividing position is not limited.

A bolt hole is provided in each of the column-shaped steel plates 1 and 2 for mounting a reinforcing metal fitting to be described later, and a cap nut 20 is mounted inside the column-shaped steel plate in accordance with the bolt hole. .

<C> Embodiment of Steel Plate Concrete Column (a) A circular steel plate concrete column A is shown in FIGS. The existing column 11 is surrounded by a pair of semicircular column-shaped steel plates 1 and 1 divided into two. At this time, the column-shaped steel plates 1 and 1 are joined to each other at joints 4 and 4 where the diagonal line XX of the existing column 11 extends.
And the same column-shaped steel plates 1 and 1 are welded to each other by welding. A filler g, for example, concrete or mortar, is filled between the column-type steel plate 1 and the existing column 11 to form a circular steel plate concrete column A. In addition, 7 is a reinforcing bar of the existing column 11, and 10 and 12 are a lower floor column and an upper floor column of the existing column 11, respectively.

(B) Square steel plate concrete pillar B is shown in FIG.
Shown in A pair of substantially L-shaped column-shaped steel plates 2 and 2 obtained by dividing a rectangular steel pipe into two are surrounded in a similar manner to the existing columns 11. that time,
The joints 5, 5 between the column-shaped steel plates 2, 2 are installed so as to be located slightly away from the diagonal line XX of the existing column 11, and the column-shaped steel plates 2, 2 are welded by W-joining. Column type steel plate 2
Filling material g is filled between the column 11 and the existing column 11 to form a square steel plate concrete column B.

(C) A square steel concrete pillar C is shown in FIG.
Shown in The pair of L-shaped column-shaped steel plates 3 and 3 which are divided into two are surrounded by a similar shape to the existing column 11. At that time,
The joints 3 are installed so as to be positioned at joints 6 and 6 where the diagonal line XX of the existing column 11 extends, and the column-type steel plates 3 and 3 are joined.
Are welded to each other. Column type steel plate 3 and existing column 1
1 is filled with a filler g to form a square steel plate concrete column C.

The joints 4, 4 of the above-mentioned column-shaped steel plates 1, 2, 3
5, 6 are installed on the diagonal line XX of the existing column 11 or slightly displaced from the diagonal line XX, and the respective column-type steel plates are welded to each other by welding W, so that the reinforcing metal fittings to be described later are connected to the respective column-type steel plates. At the time of joining to the first, second, and third steel plates, they do not interfere with the joints 4, 5, and 6 of the respective column-shaped steel plates 1, 2, and 3, so that attachment becomes easy.

<D> Embodiment of Reinforcing Bracket (a) FIG. 5 shows the reinforcing bracket D, and FIG.
And FIG. The reinforcing bracket D is a circular steel plate concrete.
This is a metal fitting interposed between the upper and lower existing beams 21 and 22 connected to the column A to integrate the steel plate concrete column A with the beams 21 and 22. The reinforcing bracket D has a right-angled triangular shape when viewed from the side, and has a horizontal plate 16 and a vertical plate 1 forming a triangle.
7. The swash plate 15 and the rib plate 14 surrounded by the swash plate 15 are formed by welding. The vertical plate 17 of the reinforcing bracket D is
It is formed in an arc shape according to the outer diameter of the circular columnar steel plate 1.
Similarly, the horizontal plate 16 has an arc shape on the vertical plate 17 side. The horizontal plate 16 and the vertical plate 17 of the reinforcing bracket D are provided with anchors 18.
A plurality of holes (symbols are omitted) through which the material and the bolt 19 pass are respectively formed (two places in the figure). Also, the vertical plate 1
A hole is also formed in the columnar steel plate 1 corresponding to the bolt hole 7 (not shown), and a cap nut 20 is mounted at the hole position of the columnar steel plate 1 (FIGS. 1 and 2). 28 is an anchor material 18
The nut.

(B) FIG. 6 shows the reinforcing bracket E. The reinforcing bracket E is provided on the horizontal plate 16 with two right-angled triangular rib plates 14 and 1.
4 are mounted at intervals. The illustrated reinforcing bracket E is
In this case, the base end portions of the horizontal plate 16 and the rib plates 14, 14 are joined to the side surfaces of the column-shaped steel plate 1 of the steel plate concrete column A in a bracket shape. This joining is preferably performed by welding to the column-shaped steel sheet 1 in advance. The horizontal plate 16 of the reinforcing bracket E is joined to the beam 21 by four anchor members 18 and nuts 28.

(C) FIG. 3 shows the reinforcing bracket F. The reinforcing bracket F is composed of a square steel plate concrete column B or C and an existing beam 2.
It is a metal fitting that is interposed and fixed at the joints of the first and second joints. The reinforcing member F has the same shape as the reinforcing member D, and is formed in a triangular shape by a vertical plate 17 ', a horizontal plate 16', a swash plate 15 'and a rib plate 14' surrounded by them. The rest is the same as FIG. 1 and FIG.

(D) FIG. 4 shows the reinforcing bracket G. The reinforcing bracket G is composed of a square steel plate concrete column C or B and an existing beam 2.
It is a metal fitting that is interposed and fixed at the joints of the first and second joints. The illustrated reinforcing bracket G has the same shape as the reinforcing bracket E, and has a horizontal plate 16.
'And the base ends of the rib plates 14', 14 'are steel plate concrete.
This is a case where the column-shaped steel plate 3 or 2 of the column C or B is joined in a bracket shape to the side surface. This joining is preferably performed by welding to the column-shaped steel plate 3 or 2 in advance. The horizontal plate 16 ′ of the reinforcing bracket E is joined to the beam 21 by four anchor members 18 and nuts 28.

(E) The reinforcing bracket H is shown in FIG. The reinforcing bracket H is made of a circular steel plate concrete column A and existing beams 21 and 22.
This is a metal fitting that is interposed and fixed at the joint of (1). Reinforcing bracket H
Is a lower horizontal plate 26, a vertical plate 27 and an upper horizontal plate 25,
A U-shape is formed when viewed from the side, and upper and lower horizontal plates 25 and 26 are formed.
And a vertical plate 27 with a rib plate 24 attached thereto. The lower horizontal plate 26 and the vertical plate 27 of the reinforcing metal H are provided with a plurality of holes (four in the drawing) through which the anchor members 18 and the bolts 19 are inserted. Reinforcing bracket H
Vertical plate 27 is formed in an arc shape in accordance with the outer diameter of the circular columnar steel plate 1.

The reinforcing bracket H is a square steel plate concrete.
When it is installed at the joint between the column B (or C) and the existing beams 21 and 22, the vertical plate 27 is made flat and the base end surfaces of the upper and lower horizontal plates 25 and 26 are made flat. The rest is the same as FIG.

(F) FIG. 8 shows the reinforcing bracket I. The reinforcing bracket I has two rectangular rib plates 24, 24 attached to a horizontal plate 26 at an interval. The reinforcing bracket I is a horizontal plate 26
And a steel plate concrete in which the base ends of the rib plates 24, 24 are circular.
This is a case where the column A is joined to the side surface of the columnar steel plate 1 in a bracket shape. The horizontal plate 26 is joined to the existing beam 21 by four anchor members 18 and nuts 28.

The reinforcing bracket I is a square steel plate concrete.
When it is installed at the joint between the pillars B (or C) and the existing beams 21 and 22, the horizontal plate 26 and the base plates of the rib plates 24 and 24 are flattened. In addition, the rib plate 1 of each of the reinforcing fittings
The numbers 4 and 24 are plural as required.

<E> Form of joining of reinforcing metal to steel plate concrete column and existing beam (a) Reinforcement metal D is connected to steel plate concrete column A and existing beam 2
1, 2, and 5 show cases where the light emitting device is attached to the joints 1 and 22.
Shown in (Retrofitting method) According to the figure, after the steel plate concrete column A is formed, the column A
Four reinforcing brackets D are installed at the upper and lower sides of the joint between the beams 21 and 22, respectively. First, the anchor members 18 are set on the lower surface of the upper beam 22 and the upper surface of the lower beam 21.
The set of anchor materials 18 can be engraved or driven in.
By a known means. Next, the reinforcing member D is mounted on the horizontal plates 16 and the beams 21 and 22 and the vertical member 17 is mounted on the column-shaped steel plate 1 of the steel plate concrete column A by the anchor member 18 and the bolt 19, respectively. 28 is an anchor material 18
Reference numeral 20 denotes a cap nut for the bolt 19. Further, a vertical member 17 is welded to the columnar steel plate 1.

(B) Reinforcing bracket E is made of steel plate concrete column A
FIG. 6 shows a case where the antenna is attached to the joint between the existing beams 21 and 22. (Pre-adhesive construction method) First, before forming the steel plate concrete column A, the reinforcing bracket E is pre-attached to the column-shaped steel plate 1 in a bracket shape. That is, the horizontal plates 16 and 2 of the reinforcing bracket E are
The base ends of the rib plates 14 are welded. Next, the column-shaped steel plate 1 to which the reinforcing metal fitting E is attached is moved so that the reinforcing metal fitting E is positioned on the existing beams 21 and 22.
1, the horizontal plate 16 of the reinforcing metal E and the existing beams 21 and
The anchor material 18 is set on the nut 2 and the nut 28 is tightened.
Next, the column-shaped steel plates 1 and 1 are welded to each other, and a steel plate concrete column A is formed with a filler.

(C) Joining by using the above (a) and (b) together. At the joint between the column base of the steel plate concrete column A and the lower beam 21, the precast method shown in FIG.
May be joined to the joint between the capital and the upper beam 22 by using the retrofitting method (a). In addition, the above is reversed, and the above-mentioned (b) is attached to the joint portion between the column cap of the steel plate concrete column A and the upper beam 22.
And the lower beam 21 may be joined to the joint between the column base of the steel plate concrete column A and the lower beam 21 by using the post-installation method (a).

(D) Also in the case of the square steel plate concrete pillar B (or C), the existing beams 21 and 22 by the reinforcing brackets D and E are formed by using the reinforcing brackets F, G, H and I. It can be performed in the same manner as in the case of joining the steel plate concrete column A.

(E) An example of a change in the joining by the reinforcing metal can be as follows. In the reinforcing brackets D (FIGS. 1, 2 and 5), F (FIG. 3) and H (FIG. 7), the vertical plates 17, 17 'and 27 are omitted, and the horizontal plates 16, 16' and 2 are omitted.
6, 25, rib plates 14, 14 ', 24 and swash plate 15, 1
5 'may be welded to a columnar steel plate in advance (pre-adhesion method). Thereby, the bolt 19 and the cap nut 20 can be omitted.

(F) As a further modification example of the joining by the reinforcing metal, the following can be performed. Vertical plate 1 of reinforcing metal fittings D (FIGS. 1, 2 and 5), F (FIG. 3) and H (FIG. 7)
7, 17 'and 27 are omitted, or the reinforcing brackets E (FIG. 6), G (FIG. 4) and I (FIG. 8) are vertically attached to the column bases of the steel plate concrete columns A, B and C. It may be installed at the joint between the beams 21 and 22 (a retrofitting method). In that case, the horizontal plates 16, 1 in each of the reinforcing brackets D, E, F, G, H, I are used.
6 ', 26, 25 are set on the anchors 18 of the upper and lower beams 21, 22 and the rib plates 14, 14', 24 and the swash plates 15, 1 are set.
5 'is welded to the column-shaped steel plates 1, 2, 3 of the columns A, B, C. Thereby, the bolt 19 and the cap nut 20 can be omitted.

When a gap is formed between the horizontal plates 16, 26 of the metal fittings and the RC beams 21, 22 when the reinforcing metal fittings are installed, the reinforcing metal fittings may be smoothed in advance using mortar or resin, or the metal fittings may be used. By injecting the above material into the gap after installation, the adhesion is improved.

Further, by making the anchor holes of the horizontal plate and the vertical plate of each of the reinforcing members long, it is possible to adjust the installation accuracy of the metal members.

[0032]

[Action]

<B> FIG. 9 shows a comparison between the beam stress and the bending strength when a horizontal force during an earthquake acts on the frame of the structure. The bending moment of the beam 22 when the design horizontal force of the framework before reinforcement is P is indicated by a broken line. At that time, maximum j-j surface of the beam 22 mode - Instrument M ₁ is, M ₂ is respectively generated in the n-n plane. The bending moment of the reinforced beam 22 is shown by a solid line. At this time, the maximum moment M ₁ ′ on the kk plane of the beam 22 is n−
M ₂ ′ is generated on the n-plane (non-reinforced surface). Therefore, a reinforcing bracket (for example, A) is set by the maximum moment M ₁ ′ (> M ₁ ), and the bending strength of the beam 22 is determined by the moment M ₂ ′ (> M ₂ ) of the non-reinforced surface. That is, M ₂ ′ = M
₁ , the horizontal force acting on the reinforced frame from M ₂ ′> M _{2 is} P ′ (> P)

P ′ = P × M ₂ ′ / M ₂ = P × M ₁ / M ₂

Therefore, the bending strength of the beam 22 after reinforcement is improved to M ₁ / M ₂ times that before reinforcement. Incidentally, the range of setting the metal fitting, it is preferably within 1/4 the inner size span L ₀ of the beam from the beam end.

[0035]

As described above, the present invention has the following effects. <A> Existing RC columns function as filled steel plate concrete columns by reinforcing them with steel plates divided diagonally in the longitudinal direction of the same columns, significantly improving the bending and shear strength of the columns and reinforcing them. It is easy to install a reinforcing bracket at the joint between the column and the existing beam, and the bending strength of the existing beam is improved due to the brace effect of the reinforcing bracket. <B> As described above, the seismic performance can be improved without providing a new bracing material or an earthquake-resistant wall in the structure, and without changing the usage of the structure. <C> Since only the end of the existing beam is reinforced, the work is reduced and the construction period is shortened and the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a circular steel plate concrete column reinforced by a column-type steel plate according to the present invention, and a reinforcing metal fitting of the first embodiment installed.

FIG. 2 is a plan sectional view of FIG.

FIG. 3A is a cross-sectional plan view of a square steel plate concrete column reinforced with a column-type steel plate and a reinforcing bracket of the third embodiment installed.

FIG. 3 (b) is a partial sectional view of the above (a).

FIG. 4 (a) is a cross-sectional plan view showing the installation state of another square steel plate concrete pillar and the reinforcing bracket of the fourth embodiment.

FIG. 4 (b) is a partial sectional view of the above (a).

FIG. 5 is a perspective view of a reinforcing bracket of the first embodiment installed at a joint between a steel plate concrete column and a beam.

FIG. 6 is a perspective view of a reinforcing bracket according to a second embodiment.

FIG. 7 is a perspective view of a reinforcing bracket according to a fifth embodiment.

FIG. 8 is a perspective view of a reinforcing bracket according to a sixth embodiment.

FIG. 9 is an explanatory diagram for comparing the acting force and bending strength of the beam before and after the seismic reinforcement.

Claims (3)

[Claims] Claims: 1. A reinforcing structure for an existing reinforced concrete column-beam, wherein a column-type steel plate is divided into a plurality of pieces in a longitudinal direction, and the column-type steel plate is surrounded by the column-type steel plate and welded to each other. A filler is filled between the column type steel plate and the existing column to form a steel plate concrete column, and a joint between the steel plate concrete column and the existing beam is integrated with a reinforcing metal fitting. A seismic reinforcement structure for columns and beams in existing structures, characterized by being joined. 2. The seismic strengthening structure of a column-beam in an existing structure according to claim 1, wherein the column-shaped steel plate is divided into two in a vertical direction at a joint where a substantially diagonal line of the existing column extends in a plan view. A seismic retrofit structure for columns and beams in existing structures. 3. The column-beam in an existing structure according to claim 1 or 2, wherein the reinforcing member is formed by fixing a rib plate to a horizontal plate. Seismic reinforcement structure.