JP2001200643A - Base isolation construction method for existing building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation construction method for an existing building by arranging a jack for supporting an upper load and a concrete filled steel pipe surrounding an existing column to attach a base isolation device to the existing column easily by lifting the jack and eliminating the occurrence of a member to be removed after realizing a base isolation structure to minimize fireproof covering. SOLUTION: This base isolation construction method for the existing building comprises a process in which a steel pipe form 11 which is supported by a jack 13 and has a predetermined shape is arranged above a base isolation device mounting position by surrounding an existing column 1, a process in which concrete 16 is placed in the steel pipe to form a concrete filled steel pipe 10 and then an upper load is transferred into the concrete filled steel pipe 10 by lifting the jack, and a process in which the existing column 1 corresponding to the base isolation device mounting position is cut, the base isolation device is inserted into the cut section of the existing column to fix it on the existing column, and then the upper load is transferred into the base isolation device by lowering the jack to remove the jack.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of seismic isolation of an existing building, and more particularly to a method of seismic isolation of an existing building in which a seismic isolation device is securely and reliably installed between cut existing columns.

[0002]

2. Description of the Related Art In recent years, seismic retrofitting measures for existing buildings have been actively applied, and for this purpose, many proposals have been made on techniques for structuring seismic isolation of existing buildings. The seismic isolation structuring technology for existing buildings that has already been proposed can be broadly divided into:
While jacking up the existing building using jacks, insert and install the seismic isolation device in the upper structure and the cut base part,
A method of seismic isolation by jacking down, and inserting and installing a seismic isolation device on the foundation while supporting the upper structure by interposing a reinforcing support around the existing pillar without using a jack After that, it can be classified as a seismic isolation structure by cutting and removing the support for reinforcement.

[0003] Japanese Patent Application Laid-Open No. 2-20767, which describes an example of the jack system, first digs out a support pile of an existing building, and installs a temporary support around the support pile. A jack is installed at the top and the jack on the temporary support is jacked up to change the axial force of the support pile to the temporary support.

[0004] The work after the change of the axial force is to disassemble the support pile with the released axial force and build a steel column to be replaced with the support pile, thereby installing a seismic isolation device between the steel column and the existing building. Install,
A typical method is to convert the axial force of the temporary support to a steel column by jacking down and then to make the existing building a seismic isolation structure. However, in this method, it is essential to excavate the ground until the pile is exposed in order to install the seismic isolation device on the pile supporting the building. It requires a large amount of difficult work, especially when the column bears an excessively large axial force. ing.

There has also been proposed a method of cutting a pillar of an existing building to achieve a seismic isolation structure. However, in any method, since it is necessary to temporarily support the load of the upper structure, a jack is set on the slab, and the support strut is placed on this, and the support strut buckles. The load of the superstructure must be received as an axial force while avoiding the above. For this reason, a bulky structure having appropriate strength has to be obtained. Furthermore, the support strut is not required after the building is seismically isolated, but rather needs to be removed because it becomes a hindrance, resulting in high removal costs.

On the other hand, as an example not using a jack, there is a method disclosed in Japanese Patent Application Laid-Open No. 9-100634. In this method, the surface finish of the existing pillar 31 is removed,
Embed anchor dowels 32 and 33 corresponding to the strength are attached and placed on the upper and lower parts of the existing column 31 except for the part to be cut, and a column-wound reinforcing steel plate 36 provided with a stud dowel 34 and a grout partition plate 35 on its outer periphery is welded. (See FIG. 8). Next, grout mortar is injected and hardened into the portions where the upper and lower stat dowels 34 are arranged,
The middle part 37 of the existing column 31 is cut with a diamond chain cutter to remove the installation part of the seismic isolation device (see FIG. 9). The upper and lower portions are covered with a pressing plate 39 for grout mortar injection (see FIG. 10). Thereafter, grout mortar is injected into the upper and lower portions of the seismic isolation device, and after being hardened, the column-wound reinforcing steel plate 36 is cut along the CUT line to complete the existing column 40 with the seismic isolation device (FIG. 11). reference).

However, in this method, the function of the column and the formwork is required at the time of construction on the column-wound reinforced steel sheet, and after the seismic isolation structure is applied, the role of the main reinforcement and the shear reinforcement of the concrete structure is burdened. Therefore, it has the following problems. In order to support the superstructure, the steel plate becomes thick, and the weight is increased, and there is a difficulty in carrying and assembling which cannot be handled by hand alone. Since it is necessary to cut out the column cutting position of the steel sheet and the casting opening of the additional concrete in advance, it becomes a special steel sheet, which leads to an increase in cost. In order to receive additional concrete in the narrow space between the steel plate and the existing column, a dam plate must be provided. After the seismic isolation device is installed, extra steel plates are cut off while supporting the upper load, so an uneven upper load is applied to the beams and the like, and removal costs are required. In the case of an independent column, a column-wound steel plate can be easily set, but in the case of a column connected to a wall such as a prism or an outer wall, it is difficult to mount the column-wound steel plate.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been improved in view of the above circumstances. In order to support an upper load, a jack and a concrete-filled steel pipe surrounding an existing column are arranged. The seismic isolation system of an existing building was constructed so that the installation of seismic isolation devices on existing pillars could be easily performed by jacking up, and the occurrence of members to be removed after the seismic isolation structure was eliminated and the fireproof coating was minimized. Offers the law.

[0009]

According to the seismic isolation method of an existing building according to the present invention, a steel pipe of a predetermined shape supported by a jack is arranged above an existing column and above a position where a seismic isolation device is mounted. Casting concrete into concrete filled steel pipes, transferring the upper load to concrete filled steel pipes by jacking up, cutting existing pillars corresponding to the mounting position of the seismic isolation device, and cutting existing pillars It consists of the steps of inserting the seismic isolation device in the place and fixing it to the cut existing column, and transferring the upper load to the seismic isolation device by jack down and removing the jack.

[0010] With this, the reloading of the upper load is performed by casting concrete into the steel pipe surrounding the existing column to form a concrete-filled steel pipe, and then receiving the upper load. Because it is possible without disposing and keeping the pipe diameter small, it is easy to handle during construction of seismic isolation structure. In addition, even after the seismic isolation structure is completed, any cuts can be eliminated and fireproofing can be minimized. Further, the concrete-filled steel pipe can be used for maintenance of the seismic isolation device.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the seismic isolation method of an existing building according to the present invention, after preparing for construction such as roughening of existing columns, the existing columns are supported by jacks above the mounting position of the seismic isolation device. A steel pipe with a predetermined shape is placed, concrete is poured into the steel pipe to form a concrete-filled steel pipe, and then the upper load is transferred to the concrete-filled steel pipe by jacking-up to correspond to the mounting position of the seismic isolation device. After that, the seismic isolation device is inserted into the existing column at the cutting point, fixed between the cut existing column and the slab, and the upper load is transferred to the seismic isolation device by jack-down. The construction has been completed by removing the jack. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 6 show a construction procedure of a seismic isolation method for an existing building according to the present invention. Fig. 1 shows the preparation process before the upper load of the existing building is changed from the existing column to the upper load supporting column in order to convert the existing building into a seismic isolation structure. As shown in FIG. 1, the finish of the existing pillar 1 is removed together with the mortar in the upper part of the seismic isolation device mounting position to roughen the surface.

Next, in order to secure a rotation space for the diamond wire saw when cutting the pillar, coring 2 of the existing pillar is performed. Since the workability is improved by dividing and reducing the weight, not only the column is cut at two places in the horizontal direction, but also two places in the vertical direction between the horizontal cut surfaces, so that the core is removed. Is performed in advance at a total of four locations of 2 locations × 2 stages as shown in the figure. In this case, performing the coring 3 for the hoop reinforcement at the column / beam joint also improves the workability of the additional concrete.

In FIG. 2, the reinforcing bars of the added concrete (a)
And (b) a step of constructing a concrete-filled steel pipe by embedding a steel pipe formwork and placing additional concrete. As shown in FIG. 2 (a), the reinforcing bars of the additional concrete are fixed to the upper existing slab 4 and the beam 5 with a resin anchor using the vertical reinforcement 6 of the additional part as a bending reinforcement. or,
The hoop 7 of the additional portion is wound up and arranged except for a portion to be removed in order to install a seismic isolation device in a later process. Pillar
At the beam joint, the split hoop 8 is laid through the beam and then welded to be integrated. In the present embodiment, by forming the concrete-filled steel pipe 10, the main reinforcing bar of the expanded concrete portion is basically unnecessary, and the reinforcing bar is also implemented with the result value calculated for the strength in relation to the steel pipe form 11. Therefore, the amount of reinforcement required is significantly reduced as compared with reinforcement reinforcement for ordinary concrete.

Next, as shown in FIG. 2 (b), an operation for constructing a concrete-filled steel pipe 10 is performed for the additional striking portion above the portion of the existing column 1 to be cut and removed. That is, jacks 13 are arranged at predetermined intervals on a slab 12 around the existing column 1, a normal formwork 14 that forms the bottom of the concrete-filled steel pipe 10 is arranged on the jacks, and an upper base for the seismic isolation device is arranged. After the anchor 15 for the streak is set at a predetermined position, the steel pipe form 11 in which a required number of stud dowels are implanted is buried thereon. The steel pipe formwork 11 is transported to the site in a state where the steel pipe formwork is divided into a plurality of sections, and is arranged so as to surround the existing columns, and is integrated by welding or the like. The steel pipe is preferably divided into two parts in consideration of the future axial force, since it is desirable that the number of welded parts be small, but the present invention is not limited to this.

Next, the jack 13 is slightly jacked up using a hand-operated hydraulic pump or the like, and a space for placing additional concrete is provided between the upper existing slab 4 and the beam 5 and the portion of the existing column 1 to be cut and removed. However, this jack-up is performed with a strength enough to support a steel pipe form or the like, and the upper load is still supported by existing columns. The work in this step is completed by placing additional concrete 16 in the steel pipe form 11 whose position has been set by jacking up.

[0017] By the above construction, the additional concrete 1
When the concrete 6 is cured until it exhibits a predetermined strength, a solid concrete-filled steel pipe 10 reinforced with the steel pipe form 11 and the vertical main reinforcement 6 and the hoop reinforcement 7 of the expanded concrete is formed. In addition, the anchor 15 for reinforcing the upper frame of the seismic isolation device.
Uses a mechanical joint system so that existing columns can be easily cut. The concrete for the additional striking portion of the existing column 1 is cast by a press-fitting method, so that the concrete is surely filled to the lower part of the existing slab on the upper floor.

FIG. 3 shows a process of removing a part of the existing pillar at the cut-off position in order to change the upper load and install the seismic isolation device. In this process, the jack 13
Is removed to remove the formwork 14 forming the bottom of the concrete-filled steel pipe 10, and the jack 13 is reset so as to support the concrete-filled steel pipe 10 having developed strength, and then jacked up again. ing. As a result, the concrete-filled steel pipe 10 on the jack is pushed up, and the long-term axial force due to the upper load shared by the existing column 1 is changed from the existing column 1 to the concrete-filled steel pipe 10. At the time of this refilling work, the load axial force of the jack 13 is carefully checked with a load meter attached to the jack 13 to prepare for cutting off the existing column 1 with a diamond wire saw.

Next, a diamond wire saw is set at the cut position of the existing column, and the existing column 1 is divided vertically and horizontally in order to remove the lightly cut piece 1 '. Therefore,
The cutting and removal of the existing column 1 can be performed extremely smoothly because the operation of the diamond wire saw can be performed in the state where the pressing force of the upper load does not exist at all by the above-described process. Then, the long-term axial force that the existing column 1 bears is safely converted to the concrete-filled steel pipe 10 by cutting the existing column 1, and the entire upper load is supported by the concrete-filled steel pipe 10 and the jack 13. Become.

In the present invention, even if the existing column is cut and removed and the entire upper load is supported by the concrete-filled steel pipe 10, the present invention provides a concrete-filled steel pipe with an increased concrete diameter. Since the upper load is replaced by a concrete-filled steel pipe that requires only a small amount, it is possible to support the upper load without using any other members. In addition, buckling of the concrete-filled steel pipe 10 is hardly generated.

FIG. 4 shows the steps of (a) arranging the base of the seismic isolation device on the slab, and (b) installing the formwork and placing concrete of the gantry. The pedestal 17 of the seismic isolation device is built on the slab 12,
In the slab, if necessary, it is fixed in the slab and the underground beam with a resin anchor, and then the cage arrangement 19 is performed. Then
As shown in FIG. 4 (b), the lower base plate 20 for installing the seismic isolation device is set at a predetermined level, temporarily fixed by welding, and the formwork 21 of the gantry is built.
2 has been cast. In this case, the lower base plate 2
Filling is surely performed by a press-fitting method so that no voids are formed in the lower part of 0, and the concrete is cured until it exhibits a predetermined strength.

FIG. 5 shows the process of setting the seismic isolation device on the lower base plate and connecting the seismic isolation device to the existing upper column reinforced with concrete-filled steel pipe. In this process, all of the upper load is
First, the seismic isolation device 25 to which the upper base plate 24 is attached is set on the lower base plate 20 of the gantry 17 constructed on the slab 12 while the jack and the jack 13 are supported. Then, the reinforcing bar of the upper base 26 of the seismic isolation device is mechanically fixed to the reinforcing bar 15 of the concrete-filled steel pipe 10, and the cage-shaped reinforcing bar 23 is provided. Next, the upper base plate 24 of the seismic isolation device 25 is connected to the existing column 1 or the like reinforced with the concrete-filled steel pipe 10. In this connection, the non-shrinkable mortar 27 is filled between the upper base plate 24 and the cut surface of the existing column 1 to achieve integration, and the non-shrinkable mortar is cured until it exhibits a predetermined strength.

FIG. 6 shows a state in which the seismic isolation device is connected to an upper existing column reinforced with additional concrete, and all of the upper load is replaced by the seismic isolation device. Seismic isolation device 25
Is completed, the jack 13 is removed from the concrete-filled steel pipe 10 and all of the upper load is transferred to the seismic isolation device 25, but the work of removing the jack 13 from the concrete-filled steel pipe 10 is performed in a usual manner. . That is,
By lowering the jack 13 interposed in the lower part of the concrete-filled steel pipe 10, the concrete-filled steel pipe 10
Since all the upper loads can be removed from the concrete-filled steel pipe 10, the upper loads can be easily changed to the seismic isolation devices 25 installed on the existing columns.

Although the main steps of the seismic isolation structure of the existing building according to the present invention are completed by the above-mentioned operation, as shown in the figure, the existing columns are provided between the slab 12 and the upper beam 5 in this state. 1
-Filled steel pipe 10 with reinforced concrete and upper and lower gantry 1
There are only seismic isolation devices 25 fixed to 7, 26,
There is almost no extra member such as a steel pipe unlike the conventional method.

FIGS. 7A and 7B are plan sectional views (a) and (b) taken along arrows (A)-(A) and (B)-(B) of FIG. 6, respectively. ing. The state after completing the work of installing the seismic isolation device 25 on the existing pillar 1 is as shown in a plan sectional view (a), and the reinforcing steel for concrete arranged therein as the concrete-filled steel pipe 10 and the existing reinforcing bars are shown in FIG. Pillar 1
Is buried, but the plan view (b) shows only a state in which the gantry 17 in which the seismic isolation device 25 is arranged on the slab is installed. Accordingly, since there is no exposed portion such as the upper load supporting member or the reinforcing bar in the state of sharing the load as in the conventional example outside the concrete-filled steel pipe 10, no fire-resistant treatment is required. It is sufficient to simply attach the materials, and there is no need to remove and dispose of the components, achieving cost reduction and improving construction efficiency.

Also, when the seismic isolation device 25 is removed for maintenance in the future and is to be re-installed after inspection or converted to a new seismic isolation device,
The concrete-filled steel pipe 10 is maintained in a state where it can be used as a member equipped with a jack for temporarily changing the upper load from the seismic isolation device, and is used as a long-term maintenance member of the seismic isolation mechanism. It is functioning.

As described above, according to the seismic isolation method of an existing building according to the present invention, a steel pipe of a predetermined shape supported by a jack is arranged above an installation position of a seismic isolation device around an existing column, and the steel pipe is placed in the steel pipe. Cast concrete to form a concrete-filled steel pipe, transfer the upper load to the concrete-filled steel pipe by jacking up, cut the existing column corresponding to the mounting position of the seismic isolation device, insert the seismic isolation device and cut it It consists of the process of fixing the existing load to the existing column, transferring the upper load to the seismic isolation device by jacking down, and removing the jack, so that the reloading of the upper load is performed after forming the concrete filled steel pipe By receiving the upper load, it becomes possible without arranging other supporting columns etc. and even with a small pipe diameter. To have. Further, even after the seismic isolation structure is completed, all cuts can be eliminated and fireproofing can be minimized. It is also possible to use the concrete-filled steel pipe for maintenance of seismic isolation devices.

As described above, the present invention has been described in detail based on the embodiments. However, the method of seismic isolation of an existing building according to the present invention is not limited to the above-described embodiments, and its application range, It goes without saying that various changes can be made to the specific structure and type of the concrete-filled steel pipe and the means for changing the upper load without departing from the spirit of the present invention.

[0029]

The seismic isolation method for existing buildings according to the present invention is as follows:
A concrete-filled steel pipe is formed by placing a steel pipe of a predetermined shape supported by a jack around the existing pillar and mounting concrete inside the steel pipe above the mounting position of the seismic isolation device. After shifting to the filled steel pipe, the existing column corresponding to the mounting position of the seismic isolation device is cut, the seismic isolation device is fixed at the cutting point of the existing column, the upper load is transferred to the seismic isolation device by jack down, and the jack is removed. The following effects are exhibited by the configuration consisting of the removal process. The concrete-filled steel pipe has a small diameter and a small thickness, and can be reduced in weight, and can be easily handled and transported and assembled by hand alone. The concrete-filled steel pipe has a simple structure and can reduce the manufacturing cost. There is no cutout after the seismic isolation device is attached, which reduces costs. The fireproof coating reduces the construction cost by only using the seismic isolation device. Concrete-filled steel pipes can be used for maintenance of seismic isolation devices.

[Brief description of the drawings]

FIG. 1 is a diagram showing a preparation for an existing pillar in the present invention.

Fig. 2 Construction drawing of concrete-filled steel pipe on existing pillar

[Figure 3] Process diagram for removing a part of the existing pillars to install the seismic isolation device

Fig. 4 Mounting diagram on slab for installing seismic isolation device

Fig. 5 Setting diagram of seismic isolation device for existing columns reinforced with concrete-filled steel pipes

FIG. 6 is a work completion diagram of a process of seismic isolation of an existing building according to the present invention.

7 (A)-(A) and FIG. 6 (B)-(B).
Arrow view

FIG. 8: Installation diagram of column-wound reinforcing steel plate in conventional seismic isolation structuring method

Fig. 9 Cutaway view of existing pillars to install seismic isolation devices in the conventional seismic isolation structuring method

FIG. 10 is an injection diagram of additional mortar in a conventional seismic isolation structuring method.

FIG. 11 is a diagram showing the completion of installation of seismic isolation devices in the conventional seismic isolation structuring method

[Explanation of symbols]

1 Existing pillar, 2, 3 core removal, 4 Upper slab,
5 beams, 6 vertical bars, 7 hoop bars, 80% hoop, 10 concrete filled steel pipe, 11 steel pipe formwork,
12 slabs, 13 jacks, 14 bottom formwork,
15 Anchor of upper gantry, 16 Addition concrete, 17 gantry, 18 Reinforcing bar, 19 Bar arrangement, 20
Lower base plate, 21 formwork, 22 concrete of trestle, 23 reinforcement, 24 upper base plate, 25 seismic isolation device, 26 trestle, 27 non-shrink concrete, 31 existing column, 32, 33 anchor dowel, 34 stud dove, 35 partition plate , 3
6 Reinforced steel columns, 37 Middle part, 38 Seismic isolation device, 39 Holding plate, 40 Existing column with seismic isolation device,

Continued on the front page (72) Inventor Kazuo Hiramatsu 2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Inside Okumura Gumi Co., Ltd. (72) Inventor Noboru Sakai 2-2-2, Matsuzaki-cho, Abeno-ku, Osaka-shi, Osaka Okumura Gumi Co., Ltd. F term (reference) 2E176 AA04 BB27 BB36

Claims (1)

[Claims] 1. A step of arranging a steel pipe of a predetermined shape supported by a jack around an existing column around an existing column and mounting concrete in the steel pipe to form a concrete-filled steel pipe; The upper load is transferred to concrete-filled steel pipe by jacking up, and the existing column corresponding to the mounting position of the seismic isolation device is cut, and the seismic isolation device is inserted into the existing column at the cutting point of the existing column and fixed to the cut existing column A seismic isolation method for an existing building, which consists of the steps of removing the jacks by transferring the upper load to the seismic isolation device by jack down.