JPH10184031A - Method of earthquake-proof reinforcing for already constructed pillar beam construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earthquake-proof method capable of earthquake-proof reinforcing a already constructed pillar beam without the need of employing post-execution anchors. SOLUTION: Steel plates 8 which a projected cross-section are contacted with respect to a part of the pillar surface of pillars 1, 2 of already constructed pillar beam construction in a manner projecting from the pillar surface, and a carbon fiber sheet 10 so wound while being adhered along the pillar surface and the outer surface of the steel plate 8. As such, steel plates 8 are fixed on the pillars 1, 2, and concrete is filled in a space between the pillar surface and the inner surface of the steel plates 8; then each end of brace slant members 6 is joined to the outer surface of the steel plates 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic retrofitting method for an existing column-beam frame which is reinforced by installing a brace such as a steel frame on an existing column-beam frame made of reinforced concrete or steel reinforced concrete.

[0002]

2. Description of the Related Art As a method of reinforcing an existing column-beam frame of a building made of reinforced concrete or steel-frame reinforced concrete, there is a method of installing a steel frame brace on the column-beam frame.

[0003] In the case of this reinforcing method, it is necessary to integrate a steel frame brace as a reinforcing material and an existing frame (column / beam) to realize smooth transmission of stress at a joint.
Various modifications have been made to the connection between the steel frame brace and the frame, but in the past, in many cases, a post-installed anchor was driven into an existing column and beam, and a steel frame brace was incorporated using the post-installed anchor. The steel frame is joined to the column beam to integrate them.

[0004]

However, installation of a steel brace using the post-installed anchor as described above has the following problems.

That is, since it is necessary to drive the post-installed anchor, noise, vibration, and dust are generated at the time of the driving. There is a problem that it is necessary to discontinue use and perform construction.

[0006] Further, since a reinforcing bar or a steel frame such as a main reinforcing bar is provided in the column beam, it is necessary to drive a post-installed anchor so as not to interfere with the reinforcing bar or the like. For this reason, there is also a problem that it is difficult to position the anchor driving with respect to the existing column and beam.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a seismic retrofitting method capable of retrofitting an existing column beam frame without using post-installed anchors. It is an issue.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method of seismic reinforcement of an existing column-beam frame according to claim 1, wherein the existing column-beam frame is made of reinforced concrete or steel-framed reinforced concrete. In the seismic retrofitting method in which a brace is installed and reinforced, a steel plate formed into a convex cross-section such that at least a part to which the brace is attached protrudes from the column surface to a part of the column surface, and The steel plate is fixed to the column by winding the high-strength fiber sheet along the surface and the outer surface of the steel plate while being bonded, and the space between the column surface and the inner surface of the steel plate is filled with concrete, and the outer surface of the steel plate The end portion of the brace is attached to the end.

In the present invention, the steel plate for joining the ends of the brace is fixed to the pillar using a high-strength fiber sheet such as a carbon fiber sheet, and the brace may be attached to the steel plate by welding or the like. Noise and vibration at the time, and the amount of dust generated are greatly reduced. In addition, the post-cast concrete strengthens the integration of the steel plate into the pillar.

[0010] The tensile force between the column and the brace is
The compressive force transmitted between the columns and the braces, transmitted by the high-strength fiber sheet, is transmitted via post-cast concrete. In addition, the shearing force between the brace and the column is transmitted by friction of the post-cast concrete.

Here, the high-strength fiber sheet is an extremely high-strength material, and concrete is a material having a high compressive strength. In addition, winding the high-strength fiber sheet around a column leads to reinforcement of the column itself, which also serves as reinforcement against local destruction of a column portion which receives a compressive or tensile force from a brace, and furthermore, a beam-column joint end accompanying the installation of the brace. It is a reinforcement against the increase in the shear of the column in the above.

Although concrete is filled on the inner side of the steel plate, the amount of the concrete is sufficient to fill the space between the steel plate and the column surface, so that the column cross section does not increase so much. Next, the invention described in claim 2 is characterized in that, in the invention described in claim 1, the shape of the cross section of the steel plate is an arc shape or a triangular shape.

According to the present invention, since the surface shape of the steel plate joining the braces has an arc shape or a triangular shape, the tensile force from the brace can be transmitted to the column without local deformation of the steel plate. .

[0014]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an elevational view showing a column-beam frame part showing a part of an existing building, and the existing column-beam frame includes two columns 1 and 2 standing at a predetermined interval,
It consists of two beams 3 and 4 suspended between the columns 1 and 2.

The columns 1 and 2 and the beams 3 and 4 are made of reinforced concrete or reinforced steel concrete. A steel brace 5 is installed in a space surrounded by the columns 1 and 2 and the beams 3 and 4.

In this embodiment, as shown in FIG. 2, the columns 1 and 2 will be described as square columns. The steel frame brace 5 of the present embodiment includes four brace diagonal members 6 made of an H-section steel, a steel pipe, or the like, and diagonal plate joining steel plates 7 for joining the four brace diagonal members 6.

The steel plate 8 for joining the brace diagonal members 6 to the columns 1 and 2 has beams 3 and 4 whose longitudinal direction is vertically opposed.
A rectangular plate member having substantially the same length as the distance between the plate members, the plate member being formed into a semicircular cross section, and further, as shown in FIG. Both ends 8a
Is set to be equal to the length of one side of the cross section of the columns 1 and 2.

Next, attachment of the steel brace 5 will be described. First, a pillar surface 1a facing the other opposite pillar 2
As shown in FIG. 2, both ends 8 a of the steel plate 8 in the width direction are brought into contact with each other, and the steel plate 8 is projected from the column surface 1 a toward the other column 2. At this time, the outer surfaces of the steel plate 8 near the respective width direction ends 8a are the surfaces 1b, 1 of the columns 1, 2.
It is arranged along c.

Although not shown in FIG.
Inside, reinforcing bars and the like are arranged. Steel plate 8 as above
In a state in which the carbon fiber sheet 10 is in contact with the pillar surface 1a, a cloth-like carbon fiber sheet 10 as a high-strength fiber sheet is wound along the other three surfaces of the pillar 1 and the outer surface of the steel plate 8 while being horizontally adhered.

At this time, the carbon fiber sheet 10 is not wound around a portion of the outer surface of the steel plate 8 to which the brace diagonal member 6 is attached by welding or the like. As described above, the carbon fiber sheet 10
Is wound, the steel plate 8 is fixed to the surface 1 a of the column 1.

Next, concrete 11 is filled into the space between the columnar surface 1a and the inner surface of the steel plate 8. As a result, the steel plate 8 and the column 1 come into close contact with each other, thereby improving the integrity. For the filling of the concrete 11, for example, a hole for filling may be opened in the upper floor slab, and the concrete 11 may be poured from the hole, or a hole for filling is provided in a part of the steel plate 8. Alternatively, the concrete 11 may be injected from the hole.
However, it is more advantageous to provide a hole in the steel plate 8 itself than to open a hole in the slab on the upper floor from the viewpoint of workability and the like.

The steel plate 8 is fixed to the other column 2 by the same construction. Here, the steel plate 8 is fixed to the surfaces of the two columns 1 and 2 facing each other. Next, one end of the brace diagonal member 6 is attached to the outer surface of each of the steel plates 8 by welding or the like.

Further, the other four attached end portions are joined to the diagonal member joining steel plate 7 by welding or the like. Here, the length of each brace diagonal member 6 and the joining positions of the four brace diagonal members 6 by the steel plates 7 for joining the diagonal members may be determined based on the use of the space in the beam-column frame and the circumstances of each site. .

As a result, the steel braces 5 are installed on the existing beam-column frame, and the seismic reinforcement of the beam-column frame is completed. In the joining of the steel braces 5 as described above,
For example, the tensile force from the steel frame brace 5 is mainly transmitted to the columns 1 and 2 via the steel plate 8 and the carbon fiber sheet 10. At this time, since the carbon fiber sheet 10 is an extremely high-strength material, the carbon fiber sheet 10 can sufficiently transmit a tensile force.

The compressive force from the steel brace 5 is transmitted via the steel plate 8 and the post-cast concrete 11. At this time, since the concrete 11 has a large compressive strength, the concrete 11 can sufficiently transmit the compressive force.

The shearing force between the steel brace 5 and the columns 1 and 2 is transmitted by friction in the post-cast concrete 11. Further, in the present embodiment, the carbon fiber sheet 10 is wound around the columns 1 and 2 to reinforce the columns 1 and 2 themselves.
It also provides reinforcement against local destruction of two parts. In addition, the installation of the brace increases the shear force transmitted from the beam to the column, but the winding of the carbon fiber sheet increases the shear strength of the column end.

Moreover, in the method of installing the brace 5 according to the present embodiment, there is no noise or vibration such as driving of a post-installed anchor to the columns 1 and 2 as in the related art, and further no dust is generated.

For this reason, when the construction of the seismic reinforcement based on the present invention is adopted, there is almost no influence on the building part other than the target column-beam frame part, and it is effective as the seismic reinforcement for the building in use. In particular, it is more effective if used in combination with the case where carbon fibers are wrapped around independent columns.

Further, since the steel plate 8 as described above is brought into contact with the pillars 1 and 2 and the carbon fiber sheet 10 is wound and the concrete 11 is filled, the brace 5 is attached, so that the construction is easy.

In the above embodiment, the steel plate 8
Is fixed with a carbon fiber sheet 10 and concrete 11 is cast, and then the brace diagonal members 6 are welded to the steel plate 8.
It is not limited to this.

For example, after attaching the brace diagonal member 6 to the outer surface of the steel plate 8 first, the steel plate 8 is
May be fixed by winding the carbon fiber sheet 10 in contact with the surface.

In this case, the work of the steel plate 8 and the brace diagonal members 6 at the site is not required, which leads to shortening of the construction period. Further, the inner surface of the steel plate 8 may be processed into a rough surface, and the integrity of the steel plate 8 and the post-cast concrete 11 may be improved.

The convex shape of the cross section of the steel plate 8 is not limited to the above-mentioned arc shape, but may be a triangular cross section as shown in FIG. However, an unreasonable load is not applied to the carbon fiber sheet 10 to be wound around the triangular corner 8b.

The convex shape of the cross section of the steel plate 8 is not limited to the above-mentioned arc shape or triangular shape. However, when another convex shape is adopted, local deformation is caused in the steel plate 8 by the tensile force from the brace 5. May occur. In this case, a stiffening material such as a rib or a plate material may be appropriately provided on the inner surface side of the steel plate 8.

Further, the steel brace 5 is not limited to the above-described structure, and other known steel brace 5 such as a K-shaped brace structure as shown in FIG. 4 can be used. here,
In FIG. 4, 13 indicates a steel beam, and 14 indicates a steel brace.

In FIG. 1, the carbon fiber sheet 10
Is wrapped only around the joining portion of the brace diagonal member 6, but as shown on the left side of FIG. May be wound to further reinforce the column member.

Further, FIG. 1 shows an example in which the carbon fiber sheet 10 is wound horizontally, but the columns 1 and 2 are spirally formed.
2 and the outer surface of the steel plate 8. Further, in the above embodiment, the steel plate 8 is arranged so as to cover the entire longitudinal direction (vertical direction) of the columnar surface 1a, but the steel plate 8 may be joined only to the columnar surface 1a where the brace 5 is to be mounted. In this case, the steel plates 8 are prepared by the number of ends of the brace 5 to be attached.

Further, in the above embodiment, the case where the columns 1 and 2 are square columns is described as an example, but the present invention is also applicable to columns having other cross-sectional shapes such as circular columns. However, regardless of the cross-section of the column, the carbon fiber sheet 1 is preferably set so that the column surface and the outer surface of the contact portion of the steel plate 8 constitute a smooth continuous surface.
It is advantageous that an excessive load is prevented from being applied to the carbon fiber sheet 10 when 0 is wound and fixed.

As shown in FIG. 6, an engaging portion 1c which can be engaged with the corners of the columns 1 and 2 is provided inside the widthwise end of the steel plate 8.
May be formed to facilitate the positioning operation when the steel plate 8 is attached.

In the above embodiment, the steel plate 8 having a convex shape only in the cross section is described. However, as shown in FIG. 7, a flat steel plate member having a width equal to one side of the columns 1 and 2 is used. ,
It is also possible to use a steel plate 8 formed so that only the portion 8d for joining the brace 5 projects in a hemispherical shape.

In this case, the carbon fiber sheet 10 may be wound so that the outer surface of the flat portion of the steel plate 8 and the column surface are joined. The concrete 11 is filled between the inner surface of the hemispherical portion 8d and the first and second pillars.

[0042]

As described above, the method of the present invention for retrofitting an existing column-to-column frame does not use post-installation anchors that generate noise, vibration and dust, and has low noise and the like. Braces for seismic reinforcement of the existing beam-column structure can be easily attached.

Moreover, by winding the carbon fiber sheet, reinforcement against local destruction of the pillar itself is also achieved. At this time, when the invention of claim 2 is adopted, local deformation of the steel sheet can be prevented.

[Brief description of the drawings]

FIG. 1 is an elevational view for explaining a seismic retrofit structure according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a cross-sectional view for explaining another shape of a steel plate.

FIG. 4 is an elevation view showing another brace structure.

FIG. 5 is a view for explaining another example of a winding position of the carbon fiber.

FIG. 6 is a diagram for explaining another shape of a steel plate.

FIG. 7 is a view for explaining another shape of the steel plate.

[Explanation of symbols]

 1, 2 pillar 3, 4 beam 5 steel frame brace 6 brace diagonal 8 steel plate 10 carbon fiber sheet (high strength fiber sheet) 11 concrete

Claims (2)

[Claims] 1. A seismic retrofitting method in which a brace is installed and reinforced on an existing column-beam frame made of reinforced concrete or steel-framed reinforced concrete, wherein at least a portion where the brace is attached protrudes from a part of the column surface. The steel plate formed into such a convex cross section is abutted, and the steel plate is fixed to the column by winding the high-strength fiber sheet along the column surface and the outer surface of the steel plate while being bonded, and the column surface and the steel plate are fixed. A method for seismic reinforcement of an existing beam-column frame, characterized by filling a space between an inner surface with concrete and attaching an end of a brace to an outer surface of the steel plate. 2. The method according to claim 1, wherein the cross-section of the steel plate has a convex shape in an arc shape or a triangular shape.