JP2001295503A - Method and construction of base isolation for base section of reinforced concrete column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and construction of vibration isolation for base section of reinforced concrete column, by which the floating allowable structure of a building setting a large aspect ratio with respect to rocking vibrations caused by earthquakes can be realized with a reinforced concrete(RC) column. SOLUTION: A steel sheet which is provided with a rising section that can sufficiently restrict the horizontal displacement of the RC column by supporting the column and is also used as the bottom plate of the form for the column being placed on the upper surface of foundation concrete, from which the main reinforcement of the column is protruded by a required length, and the main reinforcement is caused to stand up through the through holes of the steel sheet. Then the sheet is fixed to the foundation concrete, by means of fixing jigs and the edges of the contacting sections of the steel sheet with the RC column and build-up section of the main reinforcement are cut off. Thereafter, the RC column, which floats accompanying the rocking vibrations, is constructed by arranging reinforcing bars and assembling the form by placing concrete.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to seismic isolation of reinforced concrete (hereinafter referred to as "RC") columns of a building for reducing seismic force by generating a lift due to rocking vibration during an earthquake. The present invention belongs to the technical field of a construction method and a seismic isolation structure, and more particularly, to a seismic isolation structure method and a seismic isolation structure in which a floating allowable structure accompanying the rocking vibration is implemented on a column base of an RC column.

[0002]

2. Description of the Related Art Conventionally, as a technique of a seismic isolation construction method and a seismic isolation structure for reducing an earthquake input acting on a building having a large aspect ratio and generating a floating phenomenon due to rocking vibration during an earthquake, there are, for example, Japanese Utility Model 6 No. -18996,
Various disclosures are known in Japanese Patent No. 2631486 (issued on July 16, 1997) and the like.

As shown in FIG. 5A, all of the prior arts disclosed in the above-mentioned publications are based on a technical idea that allows a large displacement of a building a in the horizontal direction. In order to prevent the occurrence of the above-mentioned problem, a structure in which a contact point between a building a and a foundation b supporting the building a is vertically tied is basically used.

[0004]

[Problems to be Solved by the Invention] However, in the case of a building having a large aspect ratio, the movement of the building during an earthquake is as follows.
As shown in FIG. 5B, rocking vibration based on vertical displacement becomes dominant, and a large tensile axial force acts on the seismic isolation device c. Therefore, in the case of a structure in which the building a and the foundation b are tightly connected as in the prior art, the seismic isolation device c and the foundation b that can withstand the tensile axial force are required, and they are connected by a large number of rod-shaped members or fall down. There is no other choice but to use a laminated rubber body for prevention. In addition, since the same tensile axial force acts on the pillars of the building a, the pillars need to be constructed to have a structure having a relatively high strength.

[0005] In addition, when the space between adjacent buildings is small, such as a building in an urban area, if the seismic isolation layer undergoes a large deformation, there is a danger that the adjacent building will collide with the adjacent building on the ground surface and cause a secondary disaster. is there.

Incidentally, in recent years, the present applicant has filed Japanese Patent Application
As disclosed in Japanese Patent Application No. 42759 (filed on Feb. 22, 1999), the contact between the building having a large aspect ratio and the support plate supporting the building is not tied up and down, and the displacement in the up and down direction is reduced. We have developed a seismic isolation method and a seismic isolation structure that implements a structure that allows for lifting due to rocking vibration. This principle is as described in paragraphs [0017] to [0021] of the application specification and FIG. 4 of the drawings.

[0007] However, a technique in which the above-mentioned structure that allows the lifting caused by the rocking vibration by using the RC column is not yet developed.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to target a building having a large aspect ratio, in particular, to exempt a pedestal portion of a reinforced concrete column from which an uplift allowable structure accompanying rocking vibration during an earthquake can be implemented by an RC column. It is to provide seismic construction method and seismic isolation structure.

A second object of the present invention is to reduce the seismic force by allowing the building to be lifted in response to an earthquake input to the building without binding the building to the foundation. An object of the present invention is to provide a seismic isolation construction method and a seismic isolation structure for a reinforced concrete column base that does not require the use of seismic isolation devices and has no residual displacement when an earthquake ends.

[0010] A further object of the present invention is to simplify the design of the RC column of the building since no tensile axial force is generated on the column.
In addition, when rebuilding an existing building,
An object of the present invention is to provide a seismic isolation method and a seismic isolation structure for a column base of a reinforced concrete column, which can greatly simplify construction.

[0011]

As a means for solving the above-mentioned problems, a seismic isolation method for a column base of a reinforced concrete column according to the present invention according to the first aspect of the present invention is intended to reduce the lifting caused by rocking vibration during an earthquake. A seismic isolation method for a column base of a reinforced concrete column of a building to reduce seismic force by causing the main reinforcement of the column to protrude from a top surface of a foundation concrete by a required length according to a rising amount of the building, and On the upper surface of the concrete, a bottom formwork / steel plate supporting the reinforced concrete column and having a rising portion sufficient to restrain horizontal displacement of the reinforced concrete column is placed, and the column main reinforcement is connected to the bottom formwork. The bottom formwork and steel plate can be transmitted through the through-holes provided in the combined steel plate and rise, thereby transmitting the vertical compressive force acting on the reinforced concrete column. Then, a fixing jig such as a stud is used to fix to the base concrete, and the abutting portion of the reinforced concrete column and the rising portion of the main bar of the bottom formwork steel plate are subjected to beveling treatment with a peeling material, respectively. The present invention is characterized in that columns are laid out on the basis of a steel plate that also serves as a frame, a formwork is assembled, and concrete is cast to construct a reinforced concrete column which is raised due to rocking vibration.

According to a second aspect of the present invention, in the seismic isolation method for a column base of a reinforced concrete column according to the first aspect, the bottom formwork and steel plate is embedded and fixed in the foundation concrete. .

According to a third aspect of the present invention, there is provided a seismic isolation method for a column base of a reinforced concrete column according to the first or second aspect, wherein the dowel hole coincides with the upper surface of the foundation concrete and the lower surface of the reinforced concrete column. And a dowel pin that penetrates the steel plate that also serves as the bottom formwork is fitted into the dowel hole.

The invention described in claim 4 is the first to third aspects of the present invention.
In the seismic isolation method for a column base of a reinforced concrete column described in any one of the above items, an impact cushioning material such as an impact cushioning sheet is installed on the upper surface of the steel plate also serving as the bottom formwork.

The invention described in claim 5 provides the invention according to claims 1-4.
In the seismic isolation method for a column base of a reinforced concrete column described in any one of the above, an impact buffer is installed at the top end of a rising portion of a steel plate that also serves as a bottom formwork, and a buried formwork is assembled thereon. It is characterized by building reinforced concrete columns.

According to a sixth aspect of the present invention, there is provided a seismic isolation structure for a column base of a reinforced concrete column, wherein the column base of a reinforced concrete column of a building which generates a lift due to rocking vibration during an earthquake to reduce seismic force. The main reinforcement of the column is protruded from the upper surface of the foundation concrete by the required length according to the amount of lift of the building,
On the upper surface of the foundation concrete, a bottom formwork / steel plate supporting the reinforced concrete column and having a rising portion sufficient to restrain horizontal displacement of the reinforced concrete column is placed, and the main bar of the column is the bottom bar. The bottom formwork steel plate is standing up through the through hole provided in the formwork steel plate, and the fixing work of the stud or the like is carried out so that the vertical compression force acting on the reinforced concrete column can be transmitted. The abutment portion of the reinforced concrete column and the rising portion of the main bar of the reinforced concrete column in the bottom formwork steel plate are subjected to a beveling treatment with a release material, and the floating tolerance accompanying rocking vibration is allowed. It is characterized by having a structure.

According to a seventh aspect of the present invention, in the seismic isolation structure of the column base of the reinforced concrete column according to the sixth aspect, the bottom formwork and steel plate is embedded and fixed in the foundation concrete. I do.

According to an eighth aspect of the present invention, there is provided a seismic isolation structure for a column base of a reinforced concrete column according to the sixth or seventh aspect, wherein the dowel holes coincide with the upper surface of the foundation concrete and the lower surface of the reinforced concrete column. Is provided, and a dowel pin penetrating the steel plate also serving as the bottom formwork is fitted into the dowel hole.

The invention described in claim 9 is the invention according to claims 6 to 8
In the seismic isolation structure of the column base of the reinforced concrete column described in any one of the above, an impact cushioning material such as an impact cushioning sheet is provided in a gap between the reinforced concrete column and the bottom formwork steel plate. It is characterized by.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show an embodiment of a seismic isolation method for a column base of a reinforced concrete column according to the first aspect of the present invention. This seismic isolation construction method for the column base of the reinforced concrete column 1 is implemented in order to construct a building that generates a lift due to rocking vibration during an earthquake to reduce seismic force.

First, the main column 2 is projected from the upper surface of the foundation concrete 3 by a required length corresponding to the amount of rising of the building. Next, on the upper surface of the foundation concrete 3, the bottom formwork steel plate 4 supporting the RC column 1 and having a rising portion 4 a sufficient to restrain the horizontal displacement of the RC column 1 is placed. Then, the column main reinforcement 2 is made to penetrate through a through-hole (not shown) provided in the bottom formwork steel plate 4 to be raised. The bottom formwork steel plate 4 is fixed to the foundation concrete 3 by a fixing jig such as a stud 8 so that a vertical compressive force acting on the RC column 1 can be transmitted.
The abutting portion of the RC column 1 and the rising portion of the column main bar 2 in the bottom formwork steel plate 4 are each subjected to application of a release agent (not shown) and edge trimming treatment with a release material such as bonding of a release sheet 9. Apply. Based on the bottom formwork steel plate 4, the main reinforcement 6 and the band reinforcement 7 arrange the columns and assemble the formwork 5 to cast concrete to construct a reinforced concrete column that is raised due to rocking vibration ( The invention according to claim 1).

As shown in FIG. 2, a total of eight column main reinforcements 2 protrude in a well-balanced manner along the position near the inner surface of the rising portion 4a of the bottom formwork steel plate 4. The number of column main bars 2 is not limited to this, and the horizontal shearing force acting on the RC column 1 is applied to the foundation concrete 3.
Number that can be reliably transmitted to Further, the projecting height of the column main bar 2 is set higher than the design lift height of the building due to the rocking vibration.

Even if the bottom formwork steel plate 4 becomes a supporting point when floating due to the rocking vibration, the bottom formwork steel plate 4 can be used.
The RC column 1 has a strength that can withstand the upward load from the column 1 and can withstand the drop impact force of the RC column 1 and is installed at the floor level. In order to transmit the horizontal shearing force acting on the RC column 1 to the foundation concrete 3 more reliably, the steel plate 4 serving as the bottom formwork may be embedded in the foundation concrete 3 and fixed. As shown in FIGS. 4A and 4B, the upper surface of the foundation concrete 3 and the R
A dowel hole 12 is formed in the lower surface of the C column 1 so as to coincide with the dowel hole 11, and the dowel pin 11 penetrates the dowel hole 12 through the steel plate 4.
(The invention according to claim 3).

In the edge cutting treatment using a release material to be applied to the contact portion of the RC column 1 and the rising portion of the column main bar 2 in the bottom formwork steel plate 4, a release agent is applied to the bottom formwork steel plate 4. This is performed by attaching a peeling sheet 9 to the rising portion of the pillar main bar 2. The edge trimming treatment is not limited to this, and may be performed only by applying a release agent or may be performed only by attaching the release sheet 9. Of course, it may be carried out by attaching the release sheet 9 to the bottom formwork steel plate 4 and by applying a release agent to the rising portion of the main pillar 2.

Of course, the edge trimming treatment with the release material is not limited to the application of the release sheet 9 and the application of the release agent. The same effect can be achieved even when the rising portion of the column main bar 2 is covered with a sheath tube (not shown) covering the entire portion. About the said bottom formwork steel plate 4, even if it installs an impact buffering material, such as the below-mentioned impact buffering sheet 13, substantially the same effect can be produced.

On the upper surface of the steel plate 4 also serving as a bottom mold, RC
An impact buffering material such as an impact buffering sheet 13 for reducing the vertical impact force of the pillar 1 is provided (the invention according to claim 4). The impact buffer has a thickness of several cm
A laminated rubber sheet of a certain degree or a lead plate is used.

As shown in FIG. 1A, the main bars 6 have the same number and arrangement as those of the column main bars 2 in plan view, and as shown in FIG. It is arranged just above the. The number and arrangement of the main bars 6 are not limited to this.

As shown in FIG. 1A, the stirrups 7 are arranged so as to surround the main stirrups 6 as shown in FIG. 1A, and as shown in FIG. As shown, reinforcing bars are arranged so as to surround the peeling sheet 9 that covers the main pillars 2. Also, the stirrup 5 is shown in FIG.
As shown in (1), it is preferable that the column-base portions of the RC columns 1 be densely arranged in structural design.

When the reinforced concrete column 1 is to be buried in the column portion and constructed by the formwork 5, an impact buffer 10 is installed at the top end of the rising portion 4a of the bottom formwork steel plate 4, and the shock absorbing material 10 is placed thereon. The buried formwork 5 is assembled to construct a reinforced concrete column (the invention according to claim 5).

In the seismic isolation structure of the column base of the reinforced concrete column 1 constructed by the above-described seismic isolation construction method, the column main reinforcement 2 is protruded from the upper surface of the foundation concrete 3 by a required length in accordance with the amount of rising of the building. I have. On the upper surface of the foundation concrete 3, the reinforced concrete column 1 is supported,
A bottom formwork steel plate 4 provided with a rising portion 4a sufficient to restrain the horizontal displacement of the reinforced concrete column 1 is placed, and the column main reinforcement 2 is a through hole provided in the bottom formwork steel plate 4. Standing up through. The bottom formwork steel plate 4 is fixed to the base concrete 3 by a fixing jig such as a stud 8 so that a vertical compressive force acting on the reinforced concrete column 1 can be transmitted.
The abutting portion of the reinforced concrete column 1 and the rising portion of the column main bar 2 in the bottom formwork steel plate 4 are subjected to edging treatment with a release material such as application of a release agent and attachment of a release sheet 9, and locking. It is configured to allow lifting due to vibration (the invention according to claim 6).

An impact buffering material such as an impact buffering sheet 13 is provided in a gap between the reinforced concrete column 1 and the bottom formwork steel plate 4 (the invention according to claim 9).

Therefore, as shown in FIG. 3, the above-mentioned seismic isolation structure can be formed by the edge-cutting treatment using the release material, as shown in FIG.
When the rocking vibration occurs during an earthquake, the rocking vibration can be separated from the bottom formwork steel plate 4 that supports the rocking vibration to cause a lifting phenomenon. Further, since the bottom formwork steel plate 4 is firmly fixed to the base concrete 3 by the studs 8, as shown in FIG.
When the C column 1 rises, the bottom formwork steel plate 4 never moves upward.

Therefore, when rocking vibration occurs during an earthquake, the RC column 1 is separated from the bottom formwork steel plate 4 that supports it, and displaced vertically as shown in FIG. The center of gravity of the building moves up and down, consuming energy that enters the building due to the earthquake.

In short, the above seismic isolation structure has the above RC
The vertical compressive force acting on the column 1 is reliably transmitted to the foundation concrete 3 via the bottom formwork steel plate 4, and the horizontal shear force is reliably transmitted to the foundation concrete 3 via the column main bar 2. Although it is transmitted, the vertical tensile force is not transmitted to the foundation concrete 3 at all.

Although not shown, the spacing between adjacent RC columns 1 is adjusted according to the magnitude of the earthquake in which the design lift occurs.

[0036]

According to the seismic isolation construction method and the seismic isolation structure for the column base of the reinforced concrete column according to the first to ninth aspects of the present invention, as in the prior art, a seismic isolation device such as a seismic isolation rubber. Without using, the seismic isolation of a building with a large aspect ratio can be realized, the seismic isolation layer on the premise of installation of such devices can be reduced to almost zero, and the effective utilization of the building increases. Moreover, no residual displacement occurs when the earthquake ends.

When a building rises during an earthquake,
The seismic force acting on the building does not increase further. Therefore, it is possible to set the upper limit of the seismic force acting on the building.
Building damage can be kept below a certain level.

Since no tensile axial force acts on the pillars of the building,
There is no need to consider this, and the column design can be simplified.

In the case of rebuilding an existing building, the existing foundation and lower body are also left, and a contact point is provided on the existing building to construct a new building, so that the design and construction of the foundation can be greatly rationalized.

[Brief description of the drawings]

FIG. 1A is a plan view showing an embodiment of the present invention,
B is an elevation view.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1B.

FIG. 3 is an elevation view showing a state in which a rising phenomenon has occurred in a column base of the RC column.

FIG. 4A is a plan view showing another embodiment of the present invention, and FIG. 4B is an elevation view thereof.

FIG. 5A is a diagram illustrating a conventional principle, and FIG. 5B is a diagram illustrating the principle of reduction of seismic energy according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reinforced concrete column 2 Column main reinforcement 3 Foundation concrete 4 Bottom formwork steel plate 4a Rising part 5 Formwork 6 Main reinforcement 7 Strip reinforcement 8 Stud 9 Peeling sheet 10 Impact buffer 11 Dowel pin 12 Dowel hole 13 Impact buffering sheet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Kasuga 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside Takenaka Corporation Technical Research Institute Co., Ltd. (72) Inventor Soichi Kitani 4-1-1 Honcho, Chuo-ku, Osaka-shi 13 Takenaka Corporation Osaka Main Store (72) Inventor Nagahito Kibayashi 8-21 Ginza, Chuo-ku, Tokyo 8-21 Takenaka Corporation Tokyo Main Store (72) Inventor Fujio Koyama Chuo-ku, Tokyo 8-21-1, Ginza Inside Takenaka Corporation Tokyo Head Office

Claims (9)

[Claims] 1. A seismic isolation method for a column base of a reinforced concrete column of a building, which raises the rock due to rocking vibration during an earthquake to reduce the seismic force. A bottom formwork steel plate provided with a rising portion sufficient to protrude by a required length according to the above, support the reinforced concrete column on the upper surface of the foundation concrete, and restrain horizontal displacement of the reinforced concrete column. And the column main reinforcement is passed through a through hole provided in the bottom formwork steel plate to rise, and the bottom formwork steel plate can transmit a vertical compressive force acting on the reinforced concrete column. The anchoring jigs such as studs are used to fix the steel to the foundation concrete. The rising portions of the streaks are subjected to beveling treatment using a peeling material, and the columns are laid out on the basis of the steel plate also serving as the bottom formwork, and the formwork is assembled, and concrete is cast and reinforced concrete which rises due to rocking vibration. A seismic isolation method for reinforced concrete column bases, which is characterized by building columns. 2. The seismic isolation method for a column base of a reinforced concrete column according to claim 1, wherein the bottom formwork steel plate is embedded and fixed in the foundation concrete. 3. A dowel hole corresponding to an upper surface of a foundation concrete and a lower surface of a reinforced concrete column is provided, and a dowel pin penetrating a steel plate also serving as a bottom form is fitted into the dowel hole. Or the seismic isolation method of the column base of the reinforced concrete column described in 2. 4. A column of a reinforced concrete column according to claim 1, wherein an impact buffer such as an impact buffer sheet is provided on the upper surface of the steel plate also serving as the bottom formwork. Seismic isolation method for legs. 5. The reinforced concrete column is constructed by installing an impact cushioning material at the top end of the rising portion of the steel plate also serving as the bottom formwork and burying the formwork thereon to assemble the formwork. 4. The seismic isolation method for a column base of a reinforced concrete column as described in any one of 4. 6. A seismic isolation structure for a column-base portion of a reinforced concrete column of a building that generates seismic force due to rocking vibration during an earthquake to reduce seismic force, wherein a main bar of the column rises from an upper surface of the foundation concrete. A bottom mold that supports the reinforced concrete column on the top surface of the foundation concrete and has a rising portion sufficient to restrain the horizontal displacement of the reinforced concrete column. A frame / plate steel plate is placed, and the column main reinforcement stands up through a through hole provided in the bottom form / plate steel plate, and the bottom form / plate steel plate is vertically acted on the reinforced concrete column. Is fixed to the foundation concrete by a fixing jig such as a stud so as to be able to transmit the compressive force of the rebar in the steel plate also serving as the bottom formwork. The abutting part of the concrete column and the rising part of the column main bar are each subjected to edging treatment with a peeling material, and have a structure that allows uplift due to rocking vibration. Seismic isolation structure. 7. The seismic isolation structure for a column base of a reinforced concrete column according to claim 6, wherein the bottom formwork steel plate is embedded and fixed in the foundation concrete. 8. A dowel hole corresponding to the upper surface of the base concrete and the lower surface of the reinforced concrete column is provided, and a dowel pin penetrating the steel plate serving also as the bottom form is fitted into the dowel hole. A seismic isolation structure for a column base of the reinforced concrete column according to claim 6. 9. An impact cushioning material such as an impact cushioning sheet is provided in a gap between a reinforced concrete column and a steel plate also serving as a bottom formwork.
Seismic isolation structure of the column base of the reinforced concrete column described in the paragraph.