JP2001193290A - Seismic isolation method for existing building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seismic isolation method for an existing building having a small amount of support to be removed by reducing the diameter of supports to be arranged between a beam attached to an existing column and a slab for supporting the upper load. SOLUTION: This seismic isolation method for an existing building can be executed by arranging upper load bearing supports 6 between a slab 6 and the upper load bearing supports 6, pouring an additional amount of concrete 18, 18' surrounding the upper load bearing supports 6 except the cutting position for attaching the seismic isolation equipment of the existing column, the existing column is cut off and the seismic isolation equipment 25 is fixed to the cut-off place, an exposed portion of the upper load bearing supports left between cut surfaces is cut off, and the upper load is shifted to the seismic isolation equipment 25 as the basic process of this method.

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] The jack system is disclosed in Japanese Patent Laid-Open No. 2-2076.
As described in Japanese Patent Publication No. 7, first, a support pile of an existing building is dug out, a temporary support is erected around the support pile, and a jack is installed on the temporary support.
By jacking up the jack on the temporary support, the axial force of the support pile is changed 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 example of this process is to convert the axial force of the temporary support to a steel column by jacking down, and convert the existing building to 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 51 is removed,
Embed anchor dowels 52 and 53 corresponding to the proof strength are attached and placed on the upper and lower parts except for the part to be cut off of the existing column 51, and a column-wound reinforcing steel plate 56 provided with a stud dowel 54 and a grout partition plate 55 on its outer periphery is welded. (See FIG. 11). Next, grout mortar is injected and hardened into the portions where the upper and lower stat dowels 54 are arranged,
The middle part 57 of the existing column 51 is cut with a diamond chain cutter to remove the installation part of the seismic isolation device (see FIG. 12). The upper and lower portions are covered with a holding plate 59 for opening grout mortar for injection (see FIG. 13). Then, grout mortar is injected into the upper and lower parts of the seismic isolation device, and after hardening, the column-wound steel plate 56 is CU
The existing pillar 60 with the seismic isolation device is completed by cutting along the line T (see FIG. 14).

[0007] However, in this method, the function of the column and the formwork is required at the time of construction on the column-wound steel plate, and after seismic isolation, the role of the main reinforcement and the shear reinforcement of the concrete structure is borne. 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. 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. The joint of the column-wound steel plate must be welded. After the seismic isolation device is installed, the extra steel plate is expensive to cut off. The exposed column-wound steel sheet needs to be provided with a fire-resistant coating on the fire protection upper surface.

[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-mentioned circumstances. In order to support an upper load, a column disposed between a slab and a beam attached to an existing column is provided. Provides a construction method that does not cause buckling even if the shaft diameter is small, and provides a method of seismic isolation for existing buildings that requires less fireproof coating and removes a small amount of removal after the seismic isolation structure. are doing.

[0009]

According to the seismic isolation method of an existing building according to the present invention, an upper load supporting column is disposed between a slab and a beam attached to the existing column while maintaining a predetermined distance from an outer peripheral surface of the existing column. And the step of placing additional concrete surrounding at least the upper part of the upper load support column excluding the cutting position where the seismic isolation device of the existing column is to be mounted, and cutting the existing column corresponding to the mounting position of the seismic isolation device The seismic isolation device is inserted into the existing column at the cutting point, and the seismic isolation device is fixed to the cut existing column. It consists of the stage of transferring the load to the seismic isolation device. As a result, since the upper load supporting strut can be subjected to the upper load after being reinforced integrally with the shear reinforcement of the strengthened concrete, buckling can be prevented even if the shaft diameter is kept small, Handling becomes easy. Further, even after the seismic isolation structure is completed, the cutting point of the upper load supporting column can be reduced, and the fireproof treatment is not required.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the seismic isolation method of an existing building according to the present invention, an upper load supporting column is disposed between a slab and a beam attached to the existing column while maintaining a predetermined distance from the outer peripheral surface of the existing column. After installing the extra-strength concrete around the upper load supporting column or above and below the excluding the cutting position where the seismic isolation device of the existing column is attached, cut the existing column corresponding to the mounting position of the seismic isolation device. are doing. Next, the seismic isolation device is inserted into the cut position of the existing column, and the seismic isolation device is fixed to the cut existing column. It consists of the step of cutting and transferring the upper load to the seismic isolation device. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 7 show construction procedures of a seismic isolation method for an existing building according to the present invention. In FIG. 1, preparations are being made for construction, and the finish is removed along with the mortar over the entire length of the existing column 1 to roughen the surface.
In addition, about the existing pillar located in the outer peripheral part of a building, the wall of 1 m from the pillar outer surface is scraped off. Next, for the purpose of securing a rotation space for the diamond wire saw when cutting the pillar, core removal 2 of the existing pillar 1 is performed, but in the work to be described later, when removing and carrying out the cut part of the existing pillar, the cut piece is removed. Since the workability is improved by dividing and reducing the weight, not only can the pillar be cut at two places in the horizontal direction,
Two vertical cuts are made between the horizontal cut surfaces.

The coring is performed in advance at a total of four places of 2 places × 2 steps. However, in order to install the seismic isolation device in the middle of the existing column 1, a slab as shown in FIG. In order to install the seismic isolation device between the slab and the lower end of the existing column 1 as shown in FIG. 'May not be left, and the position of the core removal will be changed according to each case 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.

FIG. 2 shows a process of arranging the upper load supporting column between the slab and the beam attached to the existing column.
In the following steps, the seismic isolation device will be described as being installed in the middle of the existing column, and as shown in the figure, a predetermined interval is secured from the outer peripheral surface of the existing column to the slab 4 and the existing column. A flat jack 5 for adjustment is arranged on the slab 4 in order to arrange an upper load supporting column 6 made of a square steel pipe filled with concrete inside between the beam 8 to be attached. Care is taken that this flat jack 5 is located above the underground beam, and the upper load support column 6 is pushed up and fixed using a hand-operated hydraulic pump or the like to support the upper load. The number of the upper load supporting columns 6 is the same as the number of beams to be attached to the column, and a plate 7 is attached to the top end of the upper load supporting columns 6 so that the plate 7 is in close contact with the lower end of the beam on the upper floor. Injecting non-shrink mortar and installing a camber as necessary, the lower end of the beam 8 and the upper load support column 6 are brought into close contact with each other. And
When the seismic isolation device is installed between the slab and the lower end of the existing column 1, the lower end of the upper load supporting column 6 is exposed together with the flat jack 5 until it is cut off and removed. Since the flat jack is lowered after the seismic isolation device is installed, and the upper load supporting column 6 is opened, it is necessary to maintain the jack downable state.

Further, in the above-described embodiment, a flat jack or the like is interposed under the upper load supporting column 6, but these jack-ups are not indispensable, and the upper load supporting column 6 is placed on the slab 4. By directly arranging and injecting the non-shrinkable mortar into the lower end thereof, a desired function can be exhibited even when the slab 4 and the lower end of the upper load supporting column 6 are brought into close contact with each other. That is, when the upper load supporting column 6 is fixed between the slab and the lower end of the beam on the upper floor with a non-shrink mortar or the like, the coring of the existing column that has been constructed to secure the rotation space of the diamond wire saw described above, The change of the axial force from the existing column to the upper load supporting column can be performed without any trouble within a small movement range between the upper and lower slabs according to the cutting of the existing column.

FIG. 3 shows the reinforcement (a) of the reinforcing concrete.
And the step of carrying out the form-building and placing of the additional concrete (b). The vertical reinforcement of the additional portion is fixed as a bending reinforcement by the resin anchor 11 in the slab 4 on the floor where the seismic isolation device is installed, the existing slab 9 on the upper side, and the beam 10. The hoop bars 12 of the additional portion are formed so that the high-strength spiral hoop bars are located at the four corners, except for the portion to be removed in order to install the seismic isolation device in a later step. Roll up and arrange. The column / beam joints penetrate the beam, arrange the split hoops 13 in a reinforcing bar, and then weld and integrate them.

Next, form frames 14 and 15 are erected at the top and bottom of the existing column 1 and the anchor 16 for reinforcing the upper base of the seismic isolation device is set at a predetermined position. 18 'is being cast. As a result, the upper load supporting strut 6 can be used for the concrete upholstery 18 except for the part to be removed to install the seismic isolation device.
When the concrete is set to a state embedded with a flat jack in 18 ′ and is cured until the reinforced concrete 18 or 18 ′ develops a predetermined strength, the hoop 12 is formed by the hoop 12 in the same manner as the vertical main reinforcement of the reinforced concrete. The reinforced and strong state will be maintained. In addition, the anchor 16 is of a mechanical joint type so that the existing pillar can be easily cut, and concrete for an additional part over the existing pillar is poured by a press-fitting method, and the concrete is surely filled under the slab on the upper floor. Let me.

Further, in the present embodiment, the lower part of the existing column 1 is cut so that the seismic isolation device is installed in the middle of the existing column 1, and the existing column 1 'is left on the slab. When the seismic isolation device is installed directly on the slab as described in (1), the arrangement of the hoop reinforcement 12 of the additional hitting portion with respect to the lower portion of the upper load supporting column 6, the embedding of the formwork 15 and the additional hitting of the concrete 18 'are performed. Omitted, the lower part of the upper load supporting column 6 with the flat jack or the like interposed is left exposed.

FIG. 4 shows a process of removing a part of the existing pillar at the cut-off position in order to install the seismic isolation device. As described above, when the intermediate portion below the existing column 1 is cut to leave the existing column 1 ′ on the slab, the reinforcement of the hoop bar 12 of the additional hitting portion with respect to the lower portion of the upper load supporting column 6. Since the form 15 is erected and the concrete 18 ′ is reinforced, the upper load supporting column 6 is pushed up by a flat jack or held by the reinforced concrete in a state of being in close contact with the slab 4 and the beam 8. I have. Therefore, a part of the long-term axial force that the existing column 1 bears is partially shared by the upper load supporting column 6. Therefore, a diamond wire saw is set at the cutting position of the existing column 1, the column is cut in the vertical and horizontal order, and the cut and lightened cut piece is removed. By cutting the existing column, the long-term axial force that the existing column 1 bears is replaced by the upper load supporting column 6, and the upper load supporting column 6 supports all of the upper load.

On the other hand, when the seismic isolation device is directly disposed on the slab 4, the additional concrete 18 'is omitted, and
The lower portion of the upper load support column 6 with a flat jack or the like interposed is in a state of being exposed. Therefore, in the case of the present embodiment, it is possible to jack up the flat jack again and push up the upper load support column 6 upward. Can also be reduced. Therefore, the existing pillar 1 can be cut off by the diamond wire saw in a state where the pressing force is removed, so that the existing pillar 1 can be cut and divided and removed very smoothly.

As described above, the cutting and removal of the existing columns are performed by any of the above-mentioned methods. In any case, in the present invention, most of the upper load supporting columns 6 are made of the upholstered concrete. 18 or 18 ', which is reinforced and held alone, and the only exposed portion is the narrow portion left in the gap between the cut surfaces for installing the seismic isolation device. Even if the upper load is rearranged for the small-diameter upper load supporting column 6, buckling of the upper load supporting column 6 hardly occurs.

In FIG. 5, (a) reinforcing bars of the base of the seismic isolation device,
The process which builds a formwork and puts in additional concrete (b) is shown. The pedestal 20 of the seismic isolation device is constructed on the cut surface of the existing column 1 'or the slab 4 reinforced with reinforced concrete and reinforced concrete 18'. After being anchored in the reinforced lower existing column 1 'or slab 4 or in the underground beam with a resin anchor, the cage arrangement 21 is performed as shown in FIG. 5 (a). Next, the lower base plate 17 for installing the seismic isolation device is set at a predetermined level and temporarily fixed by welding, and then, as shown in FIG. Concrete 23 for casting. At this time, the lower part of the lower base plate 17 is securely filled by a press-fitting method so that no void is formed, and the concrete is cured until the concrete develops a predetermined strength.

FIG. 6 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. In this step, the seismic isolation device 2 with the upper base plate 24 attached
5 is set on the lower base plate 17 constructed on the lower existing column 1 '. Then, the reinforcing bar of the upper base 26 of the seismic isolation device is mechanically fixed to the concrete additional portion 18 and arranged in a cage shape 27. Next, the upper base plate 24 of the seismic isolation device 25 is connected to the concrete additional portion 18 and the reinforced existing column 1 or the like. In this connection, the non-shrinkable mortar 28 is filled between the upper base plate 24 and the cut surface of the existing column 1 to strengthen the integration, and the non-shrinkable mortar is cured until it exhibits a predetermined strength.

FIGS. 7 and 8 show a state in which the seismic isolation device is connected to upper and lower existing columns reinforced with additional concrete, and all of the upper load is replaced by the seismic isolation device. FIG.
An embodiment in which a seismic isolation device is installed at an intermediate portion of an existing pillar 1 is shown. In this embodiment, as shown in FIG. 7A, when the installation of the seismic isolation device 25 is completed, the four upper load supporting columns 6 are cut and removed, and all of the upper loads are isolated. The process is shifted to the device 25. The cutting of the upper load supporting column 6 is performed by a usual method, and the axial load from the upper load supporting column 6 to the existing column is changed without interruption by cutting and removing the upper load supporting column 6.

FIG. 7B is a diagram showing the state of FIG.
(A) It is a plane sectional view by an arrow, and only the additional concrete 18 'which arranged the seismic isolation device 25 on the slab is arrange | positioned. Therefore, since there is no exposed portion of steel pipes or reinforcing bars outside the reinforced concrete 18, 18 ', the fire-resistant treatment is sufficient only by attaching the fire-resistant covering material to only the seismic isolation device, and cost reduction and Improvement of construction efficiency has been achieved.

Further, in this embodiment, in order to facilitate the above-mentioned cutting operation, a jack or the like is temporarily fitted between the additional concrete 18 of the existing column and the additional concrete 18 'of the lower part. Means for alleviating the pressing force applied to the cutting instrument at the time of cutting by jacking up the cutting instrument is naturally considered as necessary.

FIG. 8 shows an embodiment in which a seismic isolation device is installed between the lower end of the existing column 1 and the slab. Also in the present embodiment, as shown in FIG.
When the installation of the seismic isolation device 25 is completed in the same manner as in the embodiment, the four upper load supporting columns 6 are cut and removed, and all of the upper loads are transferred to the seismic isolation device 25 by changing the axial force. Has been migrated.

However, in the case of the present embodiment, all of the upper load can be reliably and easily changed from the upper load supporting column 6 to the seismic isolation device installed on the existing column.
That is, the lower part of the upper load supporting column 6 is exposed to the outside together with the flat jack interposed between the concrete reinforced concrete 18 and the slab from below. Therefore,
This is because the operation of the flat jack is free and the upper load can be easily removed from the upper load support column 6 by lowering the flat jack.

FIG. 8B is a plan sectional view taken along the arrows (A)-(A) of FIG. As shown in the drawing, after completing the work of installing the seismic isolation device on the existing pillar, only the concrete 23 of the gantry 20 on which the seismic isolation device 25 is arranged is placed on the slab. Since there is no exposed portion of steel pipes or reinforcing bars outside of 18, the fire-resistant treatment is sufficient to install fire-resistant coating only on the seismic isolation device, achieving cost reduction and improvement of construction efficiency. .

FIGS. 9 and 10 show an embodiment in which the present invention is applied to a column at a corner and a column connected to a wall, which are difficult to perform by the conventional jackless method. FIG.
Is an embodiment applied to a pillar at the corner of the outgoing corner, and a seismic isolation device 31 is installed on the pillar 30 at the existing corner of the outgoing corner to achieve seismic isolation of the existing building. The upper load support column 32 is installed between the beam 33 attached to the column 30 at the protruding corner and the corresponding underground beam, and the additional concrete 34 is connected to the column 30 at the existing protruding corner. Reinforcing bars are arranged in a state of surrounding the upper load supporting column 32, and concrete is cast. Therefore, the application of the seismic isolation method of the existing building according to the present invention to the pillars at the corners of the corners is that the construction is almost the same as ordinary on-site work and does not involve any special members or special work Therefore, it is also excellent in terms of cost and construction period.

FIG. 10 shows an embodiment in which the present invention is applied to a pillar connected to an outer wall. A seismic isolation device 41 is installed on an existing pillar 40 to make the existing building seismic. Upper load support column 42
Is installed between the beam 43 or the like attached to the existing column 40 and the corresponding underground beam, and the additional concrete 44 is arranged in a state surrounding the existing column 40 and the upper load supporting column 42. It is straightened and concrete is cast. Therefore, the application of the seismic isolation method according to the present invention to a wall of an existing building, particularly to a pillar connected to an outer wall, is excellent in terms of cost and construction period as in the above-described embodiment.

As described above, according to the seismic isolation method for an existing building according to the present invention, the upper load supporting column, which temporarily receives the upper load, is integrally reinforced with the shear reinforcing bars of the upholstered concrete, and then the upper load supporting column is reinforced. While receiving the load, only the part where the seismic isolation device is installed is exposed, and most of the other parts are buried in the reinforced concrete, so even if the shaft diameter is kept small, buckling can be prevented, Its weight is reduced to facilitate handling during construction. Further, even after the seismic isolation structure is completed, the cutting portion of the upper load supporting column can be reduced, and the fireproof treatment is performed only with the seismic isolation device to reduce the cost.

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

[0033]

The seismic isolation method for existing buildings according to the present invention is as follows:
When installing existing seismic isolation devices by cutting existing columns, the upper load support columns, which temporarily receive the upper load, are integrally reinforced with shear strengthening reinforcements of the existing columns to cast concrete. At the same time, most of the upper load support strut, except for the part where the seismic isolation device is installed, is buried in the reinforced concrete, so there is no need to worry about buckling of the upper load support strut even if the upper load is changed. Has the following effects. The upper load supporting column has a small shaft diameter or a small thickness of a steel plate, and can be reduced in weight, and can be easily handled and transported and assembled only by hand. The upper load support strut has a simple structure, so that the manufacturing cost can be reduced. It can be easily constructed even in the case of pillars connected to walls such as prisms and outer walls. Eliminating seam joints between steel plates can improve construction efficiency. The amount of cut off after the seismic isolation device is installed is small, and the cost is reduced. The fireproof coating reduces the construction cost by only using the seismic isolation device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a preparation process in a seismic isolation method for an existing building according to the present invention.

FIG. 2 is an arrangement diagram of upper load supporting columns in the seismic isolation method of an existing building according to the present invention.

Fig. 3 Schematic diagram of construction process of additional concrete for upper load support column

Fig. 4 Process diagram of removing a part of the existing pillar to install the seismic isolation device

[Fig. 5] Construction diagram of base of seismic isolation device

Fig. 6 Setting diagram of seismic isolation device for existing pillars reinforced with additional concrete

FIG. 7 is a process diagram of changing the upper load when the seismic isolation device is installed in the middle of an existing column.

8 (A) to 8 (A) and other embodiments of FIG. 7;

FIG. 9 is a diagram showing an embodiment in which the present invention is applied to a prism.

FIG. 10 is a view showing an embodiment in which the present invention is applied to a pillar connected to a wall.

FIG. 11 is an installation diagram of a column-wound reinforcing steel plate in a conventional seismic isolation structuring method.

FIG. 12 is a cutaway view of a steel plate for installing a seismic isolation device in a conventional seismic isolation structuring method.

Fig. 13 Mortar injection diagram in conventional seismic isolation structuring method

FIG. 14: Completed installation of seismic isolation device in conventional seismic isolation structuring method

[Explanation of symbols]

1 Existing pillar, 2, 3 Core removal, 4 Slab, 5
Flat jack, 6 upper load support column, 8
Beam, 12 Hoop Reinforcement, 13% Hoop, 22 Formwork, 16 Upper Frame Anchor, 17 Lower Base Plate, 18, 18 'Upholstered Concrete, 20 Frame, 21 Bar Arrangement, 22 Formwork, 23 Frame Concrete, 24 Upper Base plate, 25 seismic isolation device, 26 upper pedestal, 27 bar arrangement, 28 non-shrink mortar, 30 pillar at corner, 31, 41 seismic isolation device,
32, 42 Upper load support column, 33, 43 Beam, 3
4,44 Additional concrete, 40 Pillar connected to the wall,
51 Existing pillar, 52, 53 Anchor dowel, 54
Stud dowel, 56 pillar reinforced steel plate, 58 seismic isolation device, 60 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 DD22

Claims (1)

[Claims] 1. Excluding the step of arranging an upper load supporting column between a slab and a beam attached to an existing column while maintaining a predetermined distance from the outer peripheral surface of the existing column, and a cutting position for attaching a seismic isolation device of the existing column. Placing the additional concrete around at least the upper part of the upper load supporting column, cutting the existing column corresponding to the mounting position of the seismic isolation device, and inserting the seismic isolation device at the cutting position of the existing column. And fixing the seismic isolation device to the cut existing column, and cutting the exposed portion of the upper load supporting column from the added concrete to transfer the upper load to the seismic isolation device. Seismic isolation method for existing buildings.