JPH1061205A - Seismic reinforcement method for columns - Google Patents

Abstract

(57) [Problem] To provide a new seismic retrofitting method for a column which is superior in proof strength and deformation performance as compared with the seismic resistant structure obtained by the conventional seismic retrofitting method and can also save labor of construction. SOLUTION: In order to reinforce an existing RC column 14 by adding a sleeve wall 26, a closed steel plate unit 10 whose periphery is surrounded by a steel plate is manufactured in advance, and an intermediate portion of the column 14 and beams 17 on the upper and lower floors are manufactured. , 18 and an anchor 19 is provided, a wall reinforcement 20 of a sleeve wall is arranged via the anchor 19, and a closed mold steel plate unit 10 which is also used as a formwork is installed at the upper and lower ends of the pillar 14, After arranging the mold 16 between the closed-type steel plate units 10, the sleeve wall 26 is constructed by filling and solidifying a curable material in the closed-type steel plate unit 10 and the formwork 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reinforcing an existing reinforced concrete (RC) column by adding a sleeve wall to the column to reinforce the existing column.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for seismic reinforcement of RC columns in existing buildings due to the increasing awareness of seismic resistance of existing buildings. In general,
Such seismic strengthening methods for RC columns include tough type reinforcement in which the perimeter of the column is surrounded by a steel plate or carbon fiber for shear reinforcement, a sleeve wall is added to the column, or the entire frame between the column and beam is subjected to seismic reinforcement. There is strength type reinforcement to add walls. Here, the above-mentioned toughness type reinforcement is solely for the purpose of improving the deformability of the column, and the proof strength of the column itself hardly increases, whereas the reinforcement of the sleeve wall increases the proof strength and rigidity of the column. It is known that the strength and rigidity of the column are dramatically increased by about 2 to 3 times by adding a sleeve wall having substantially the same size as the column width. In addition, according to the sleeve wall extension reinforcement, compared with the case of adding an earthquake-resistant wall,
There is also an advantage that an opening can be provided in the frame.

Conventionally, when seismic reinforcement is performed by adding a sleeve wall to such an existing RC column, as shown in FIGS. 7 and 8, firstly, as shown in FIGS. Post-installed anchors 4 are installed on beams 2 and 3,
After arranging the wall reinforcement 5 of the sleeve wall via these anchors 4..., A formwork (not shown) is arranged and concrete is cast, so that the sleeve wall 6 is integrated with the RC column 1. The method of building is adopted.

[0004]

However, in the above-mentioned conventional seismic reinforcement method for existing RC columns, FIG.
As shown in the figure, the integrated RC column 1 and sleeve wall 6 resist oblique compression force (compression strut) against a large horizontal force generated at the time of a large earthquake. There is a problem that concrete at both ends may be pressed by the compressive force. The present invention has been made in order to effectively solve the problems of the conventional seismic retrofitting method for columns, and has superior strength and deformation performance as compared with the seismic structure obtained by the conventional seismic retrofitting method. It is an object of the present invention to provide a new column seismic retrofitting method capable of saving labor in construction.

[0005]

According to the first aspect of the present invention, in order to reinforce an existing RC column by adding a sleeve wall to the existing RC column, the perimeter is previously surrounded by a steel plate. Manufacture a closed-type steel plate unit, install an anchor on the middle part of the pillar and the beams on the upper and lower floors, arrange the wall reinforcement of the sleeve wall via the anchor, and form a mold on the upper and lower ends of the pillar. By installing the closed steel plate unit serving as a frame, and after arranging a mold between these closed steel plate units, filling the hardened material into the closed steel plate unit and the mold and solidifying the same. It is characterized by constructing a sleeve wall.

[0006] The invention described in claim 2 is the invention according to claim 1.
In the invention described in the above, to manufacture a U-shaped steel plate unit in which the periphery other than the contact portion with the column is previously surrounded by a steel plate, and use the U-shaped steel plate unit as a mold frame between the closed die steel plate units. After the installation, the closed type steel plate unit and the U-shaped steel plate unit are filled with a curable material. Here, the invention according to claim 3 is characterized in that the closed-type steel sheet unit according to claim 1 or 2 is formed in a Japanese character or a square character in a horizontal sectional view. The invention according to claim 4 is characterized in that the closed steel plate unit and / or the U-shaped steel plate unit are vertically divided into a plurality of steel plate units.

[0007] In the method for reinforcing a column according to any one of claims 1 to 5, a closed mold steel plate unit serving also as a mold is integrated with upper and lower ends of a sleeve wall to which a large oblique compressive force acts upon a large earthquake. Because of this, the closed-type steel plate unit can restrain lateral strain generated in the hardening material forming the sleeve wall when compressive force is applied, thereby preventing indentation thereof. It is possible to improve the proof stress and the deformation performance as compared with the conventional sleeve wall extension reinforcing column. Here, as the curable material, general-purpose concrete or mortar may be used as a constituent material of this kind of sleeve wall, but other curable materials having a predetermined mechanical strength can also be applied. In the intermediate portion between the closed mold steel plate units, a sleeve may be constructed by disposing a mold and filling and solidifying a curable material as in the related art, and then removing the mold and forming a sleeve wall. As in the invention according to claim 2, a U-shaped steel plate unit in which the periphery other than the contact portion with the column is previously surrounded by a steel plate is manufactured, and the U-shaped steel plate unit is also used as a mold. It is preferable to install it between the closed steel plate units, because the construction can be further facilitated and the proof strength and rigidity of the sleeve wall can be further improved.

The sectional shape of the closed steel plate unit is as follows:
Various shapes such as curled, sun-shaped, cross-shaped, and cross-shaped are applicable, but considering the continuity of the wall streaks, the ease of construction, and the filling properties of the curable material. In this case, when the length of the sleeve wall is relatively short, a braille shape is used, and when the length is long, a Japanese character is used. Is preferred. Further, as in the invention according to claim 4, the closed steel plate unit and / or
Alternatively, when manufacturing the U-shaped steel plate units, if these are divided into a plurality of steel plate units as appropriate in the up-down direction, handling at the time of construction becomes easy and further labor saving can be achieved. In addition, according to the invention as set forth in claim 5, since the closed-type steel plate unit is installed separately from the beams on the upper and lower floors, the steel plate does not directly bear the axial force, so Buckling of the steel plate can be reliably prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a column seismic retrofitting method according to the present invention will be described with reference to FIGS. First, as shown in FIG. 2, the periphery is surrounded by a steel plate 11 and the reinforcing plate 12
FIG. 3 shows a closed-type steel plate unit 10 in the shape of a Japanese character in which
A U-shaped steel plate unit 16 whose periphery other than the abutting portion with the existing RC column 14 is surrounded by a steel plate 15 so as to show a horizontal cross-sectional shape is manufactured. At this time, in the present embodiment, as shown in FIG. 4, the closed steel plate unit 10 is divided into two steel plate units 10a and 10b in the vertical direction at the upper and lower portions, respectively. , Divided into four steel plate units 16a.

On the other hand, as shown in FIG.
Anchors 19 are respectively installed on the intermediate portions where the U-shaped steel plate unit 16 is disposed and the beams 17 and 18 on the upper and lower floors, and the wall reinforcement 20 of the sleeve wall is arranged so as to be connected to these anchors 19. To streak. The anchor 19 in the middle part of the RC column 14 is a post-installed anchor, and as the anchors 19 of the beams 17 and 18, existing means such as a chemical anchor, a carved anchor, and a post-installed anchor are applied. In parallel with this, as shown in FIG. 4, the steel plate units 10a and 10b constituting the closed steel plate unit 10 are attached to the upper and lower ends of the RC columns 14 as molds, respectively. Steel plate unit 10, 1
U-shaped steel plate unit 1 which is also used as a formwork in the middle part between 0
6 are attached in such a manner as to be inserted sequentially from the side of the RC column 14, and are fixed by the temporary angle steels 21 which are vertically arranged with the steel plate units 10a, 10b, 16a. I do.

At this time, the steel plate unit 10a is installed at a distance of 20 to 30 mm from the beams 17 and 18 on the upper and lower floors, and these gaps are closed by the temporary angle iron 22. An air vent hole 23 is formed in the upper part of the upper steel plate unit 10a.
As shown in FIG. 5, a pipe 24 made of vinyl chloride or the like extending near the lower surface of the beam 17 is attached. On the other hand, an injection hole 25 for press-fitting concrete or mortar (curable material) is formed in the lower steel plate unit 10a. Next, after fixing the closed-type steel plate unit 10 and the U-shaped steel plate unit 16, the injection hole 25 is formed.
Concrete or mortar is press-fitted into the inside and solidified to form the sleeve wall 26 with the RC column 14, and the temporary angle steels 21 and 22 are removed to complete the seismic reinforcement of the existing RC column 14. I do.

[0012] According to such a seismic reinforcement method for columns, RC
The pillars 14 are integrally provided with the sleeve wall 26 using the closed mold steel plate unit 10 and the U-shaped steel plate unit 16 which are also used for the formwork, and the upper and lower ends of the sleeve wall 26 on which a large oblique compressive force acts upon a large earthquake. In the part, the closed steel plate unit 10
Is arranged, the closed-type steel plate unit 10 can restrain lateral strain generated in the concrete or mortar constituting the sleeve wall 28 when compressive force is applied, thereby preventing indentation. . As a result, as shown in FIG. 6, it is possible to significantly improve the proof stress and the deformation performance with respect to the seismic force as compared with the conventional sleeve-wall-added reinforcing column shown in FIG. In addition, between the closed steel plate units 10,
Since the U-shaped steel plate unit 16 also serves as a formwork, the U-shaped steel plate unit 16 can be attached so as to cover the wall 20 from the side of the RC column 14, and the mold is removed. Since there is no need, construction is easy, and the proof strength and rigidity of the sleeve wall can be further improved.

Further, the closed steel plate unit 10 and the U-shaped steel plate unit 16 are divided in advance to produce a plurality of steel plate units 10a, 10b, 16a, which are sequentially attached at the site and integrated with the temporary angle steel 21. Since it is fixed in a fixed manner, it is easy to carry in and attach during the construction and to handle the work, and to save labor. Further, the steel plate unit 10a is connected to the beams 1 on the upper and lower floors.
7 and 18 are set apart from each other by 20 to 30 mm, and these gaps are closed by the temporary angle irons 22.
1 does not directly bear the axial force, and thus the buckling of the steel plate 11 during an earthquake can be prevented.

In the description of the above embodiment,
Although only the case where the U-shaped steel plate unit 16 serving as a mold is disposed between the closed-type steel plate units 10 has been described, the present invention is not limited to this. Formwork can also be used. Also,
The closed-type steel plate unit 10 and the U-shaped steel plate unit 16 may be manufactured integrally, respectively, and are divided into a plurality of steel plate units 10a, 10b, and 16a as in the above-described embodiment in consideration of handleability. In this case, it is possible to appropriately divide the number into a number according to various conditions at the time of handling. Further, as for the cross-sectional shape of the closed-type steel plate unit 10, in addition to the above-mentioned Japanese character shape, if the length of the sleeve wall is relatively short, a square shape may be used. If it is long, a letter-shaped object may be used.

[0015]

As described above, according to any one of the first to fifth aspects of the present invention, the closed-type steel plate unit serving also as a mold is integrally incorporated into the upper and lower ends of the additional sleeve wall. Therefore, the closed-type steel plate unit can prevent the hardening material from being pressed down due to the compressive force acting at the time of a large earthquake, and can greatly improve the proof stress and the deformation performance. In particular, according to the invention as set forth in claim 4, handling at the time of construction becomes easier and labor can be saved, and according to the invention as set forth in claim 5, the closed-type steel plate unit Are installed separately from the beams on the upper and lower floors, so that the steel plate does not directly bear the axial force, and thus the effect of preventing buckling of the steel plate during an earthquake can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a pillar portion constructed according to an embodiment of a method for reinforcing a pillar according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a front view showing a state where a steel plate unit for constructing the sleeve wall of FIG. 1 is installed.

FIG. 5 is an enlarged sectional view of an air vent hole part of FIG.

FIG. 6 is a load-deformation curve showing the effect of seismic reinforcement according to the present invention.

FIG. 7 is a plan view showing a pillar portion constructed by a conventional pillar seismic retrofitting method.

FIG. 8 is a longitudinal sectional view showing a pillar portion constructed by a conventional pillar seismic retrofitting method.

FIG. 9 is a schematic diagram showing a deformation mode when an earthquake acts on the column portion of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Closed-type steel plate unit 11, 15 Steel plate 14 Existing RC column 16 U-shaped steel plate unit 10a, 10b, 16 Split steel plate unit 17, 18 Beam 19 Anchor 20 Wall reinforcement 26 Sleeve wall

Claims (5)

[Claims] 1. A seismic retrofitting method for a column in which a sleeve wall is added to an existing RC column to reinforce the column, wherein a closed-type steel plate unit whose periphery is previously surrounded by a steel plate is manufactured, and an intermediate portion of the column and Anchor is installed on the beams on the upper and lower floors, and the reinforcement of the wall of the sleeve wall is arranged via the anchor, and the upper and lower ends of the pillars are installed with the closed mold steel plate unit serving as a formwork, After arranging a formwork between these closed-type steel plate units, the above-mentioned closed-form steel plate unit and the mold are filled with a hardening material and solidified to construct the sleeve wall. Reinforcement method. 2. A U-shaped steel plate unit in which the periphery other than the contact portion with the RC column is surrounded in advance by a steel plate,
2. The curable material is filled in the closed steel plate unit and the U-shaped steel plate unit after the U-shaped steel plate unit is installed between the closed steel plate units as a mold. Seismic retrofitting method for pillars described in. 3. The method according to claim 1, wherein the closed-type steel plate unit is formed in a Japanese character or a square shape in a horizontal sectional view. 4. The column according to claim 1, wherein the closed steel plate unit and / or the U-shaped steel plate unit are manufactured as a plurality of vertically divided steel plate units. Seismic reinforcement method. 5. The method according to claim 1, wherein the closed-type steel plate unit is installed separately from beams on upper and lower floors.