JPH09235889A - Base isolation construction method of existing building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation construction method capable of shortening a work execution period, reducing work execution cost and damping earthquake force on an upper layer floor. SOLUTION: A pit retaining wall 32 is constructed in a drilled space by drilling the ground 14 in the circumference of a first basement. Thereafter, a setting space to set a support device 34 is formed in the middle of a pillar 26a of the first basement, and a vertical load of an existing building burdened by the pillar 26a is borne by a reinforced concrete wall 18a of the first basement. Thereafter, the support device 34 free to ealstically deform in the horizontal direction is set in the setting space. Additionally, an opening part 35 is formed in the horizontal direction by breaking concrete of the wall 18a of the first basement, and a vertical reinforcement is made in an exposed state. Thereafter, the whole of the vertical reinforcement is cut off on a lower part side. Thereafter, cut end parts of a specified number of the vertical, reinforcements are inserted into the inside of a plural number of steel pipes fixed on a lower surface of the opening part 35, the vertical reinforcements inserted into the insides of these steel pipes are made into a steel bar damper, and the remaining vertical reinforcements are made into a spare damper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation construction method for an existing building in which a seismic isolation device is newly installed in an already constructed existing building. The present invention relates to a seismic isolation construction method suitable for existing buildings.

[0002]

2. Description of the Related Art The middle- and low-rise buildings that have already been constructed (for example, buildings with 3 to 5 floors) have high rigidity from the first floor to the top floor, and the deformation due to the earthquake input on the first floor is on the first floor. Concentration may occur, causing damage such as building collapse.

As a construction method for installing a seismic isolation device in an existing building, for example, a seismic isolation construction method for an existing building is known, which is described in Japanese Patent Laid-Open No. 20767/1990.

[0004]

However, according to the construction method disclosed in Japanese Patent Laid-Open No. 2-20767, a large underground space must be formed so that the support piles buried deep in the ground are exposed. First, it takes a lot of excavation time to form this large underground space, and the work of loading temporary support, jacks and steel columns must be carried out, which shortens the construction period and reduces construction costs. Is difficult to achieve.

The present invention has been made in view of the above circumstances, and aims to shorten the construction period and the construction cost, and promptly damp the seismic force of the upper floors in spite of a simple seismic isolation structure. The purpose is to provide a seismic isolation method for existing buildings that can be used.

[0006]

The seismic isolation construction method for an existing building according to claim 1 of the present invention is a construction method for newly installing a seismic isolation device in an existing building of middle and low rises, which is a specific lower floor. In the middle of the pillar, to form an installation space for installing a support device, and the vertical load of the existing building that the pillar has borne, the step of bearing the specific lower floor reinforced concrete wall, In the installation space, a step of installing the supporting device that is elastically deformable in the horizontal direction, and crushing the concrete of the wall of the specific lower floor to form an opening that opens in a slit shape in the horizontal direction, and in this opening In the step of vertically extending a plurality of vertical streaks that have been fixed inside the concrete in a bare state, and cutting all of the plurality of vertical streaks at the lower side to the supporting device to the existing building. When the vertical load of To, insert the cut end of the vertical stripes of a predetermined number within a plurality of steel tubes fixed to the lower surface of the opening,
The method includes a step of using the vertical bars inserted inside these steel pipes as steel rod dampers that are plastically deformed by horizontal input when an earthquake occurs, and using the remaining vertical bars as preliminary dampers.

Further, the seismic isolation construction method for an existing building according to claim 2 is a construction method in which a seismic isolation device is newly installed in an existing building of a low-middle layer having a basement floor, and the ground around the first basement floor. And constructing a pit retaining wall in the excavation space, and forming an installation space for installing a support device in the middle of the pillar on the first basement floor, and applying the vertical load of the existing building ,
The step of supporting the reinforced concrete wall on the first basement floor, the step of installing the horizontally elastically deformable support device in the installation space, and the crushing of the concrete on the wall of the first basement floor Forming an opening that opens in a slit shape in the horizontal direction, and in the opening, a step of vertically extending a plurality of vertical stripes that have been fixed inside the concrete in a bare state, and a plurality of the vertical lines. While cutting all the muscles on the lower side and introducing the vertical load of the existing building to the supporting device, insert a predetermined number of cut ends of the vertical muscles into a plurality of steel pipes fixed to the lower surface of the opening. The method includes a step of using the vertical bars inserted into these steel pipes as steel rod dampers that are plastically deformed by horizontal input when an earthquake occurs, and using the remaining vertical bars as preliminary dampers.

Further, the invention according to claim 3 is the seismic isolation method for an existing building according to claim 1 or 2, wherein the plurality of steel rod dampers extending vertically in the opening are provided above the dampers. It is a construction method including a step of fixing the side with a belt-shaped deformation preventing member having a vertical width set to a predetermined value.

Further, the invention described in claim 4 is the invention according to claim 1.
In the seismic isolation method for the existing building according to any one of 1 to 3, as a step in the preceding step of the step of forming the installation space in the middle of the pillar of the specific lower floor or the pillar of the first basement floor, This is a construction method including a step of connecting an upper position and a lower position of the pillar with a position where an installation space is formed with a pillar connecting device capable of transmitting a vertical load of the existing building.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an existing building (middle- and low-rise building) 10 made of reinforced concrete with two basement floors. This existing building 10 is a piloty where only the independent columns are erected without a wall on the first floor above the ground. It is a type of building. And the lower part of the skeleton of this existing building 10
From 2, the plurality of support piles 16 supporting the vertical load of the existing building 10 are buried in the ground 14.

FIG. 2 shows the underground structure of the existing building 10, in which the underground outer wall 18 receives the earth pressure of the ground 14.
Forms an underground space. The floor slab 20 on the first floor F1 is supported by the pillars 26a and 28a standing on the first floor B1 via the underground first floor beam 24a. Also,
The floor slab 22 on the first basement floor B1 is supported by columns 26b and 28b standing on the first basement floor B2 via a beam 24b on the second basement floor. Here, the pillar 26a that is integrally erected with the outer wall 18a of the first basement floor B1 and stands upright is referred to as an outer pillar, and the second basement floor B
The pillar 26b which is integrally formed with the outer wall 18b of the second body and stands upright is also referred to as an outer pillar. In addition, the pillars 28a and 28b that stand upright in the space of the first and second floors B1 and B2 are referred to as inner pillars.

In this embodiment, as shown in FIG. 3, a mountain retaining wall 30 that also serves as a water stop is buried in the soil around the existing building 10, and the mountain retaining wall 30 and the underground outer wall 18 are combined. Excavate the soil between to the depth of B1 on the first basement floor. Next, a space is provided between this excavation site and the underground outer wall 18 to construct the pit retaining wall 32.

Next, as shown in FIGS. 4 and 5, the concrete of the outer pillar 26a on the first basement floor B1 is crushed, the exposed reinforcing bars are removed, and an isolator (supporting device) is used.
An installation space 36 for installing 34 is formed.

The installation space 36 is located at a position where the outer wall 18a can surely bear the vertical load transmitted from the beam 24a on the first basement floor even if the supporting force of the outer pillar 26a on the first floor B1 is removed. Is formed in. In other words, the first basement B
The position close to the first beam 24a, that is, the upper end surface 36a is set to a position of a predetermined length h slightly vertically downward from the lower surface level of the beam 24a on the first basement floor B1.
A lower end surface 36b is provided at a position spaced apart by a length H corresponding to the height of the isolator 34 from below to enable the outer wall 18a to sufficiently bear the vertical load.

The isolator 34 is installed in the installation space 36, and the upper and lower flanges 34a and 34b thereof are fixed to the upper and lower end surfaces 36a and 36b with bolts. The isolator 34 employs a laminated rubber bearing in which metal plates such as iron plates and rubber are alternately laminated.

Next, as shown in FIGS. 6 and 5, the concrete of the outer wall 18a of the first basement floor B1 is crushed in the horizontal direction, and vertically extends into the slit-shaped opening 35. The plurality of vertical stripes 37 are exposed.
Here, the opening 35 that exposes the vertical stripe 37 is
In this embodiment, the height is substantially the same as the position where the isolator 34 is installed, but the height does not have to match the height of the isolator 34 as long as it is located above the pit retaining wall 32.

Then, as shown in FIG. 8, the first basement floor B1
The isolators 34 are installed on all the outer columns 26a of the outer wall of the outer wall 18a and the openings 35 are formed over the entire circumference of the outer wall 18a in the horizontal direction.
Is formed, and the vertical stripe 37 is exposed in the opening 35.

Next, as shown in FIGS. 9 and 10, all the lower end portions of the exposed vertical stripes 37 are cut off. As a result, the isolator 34 installed on the outer pillar 26a of the first basement floor B1 receives the vertical load transmitted from the beam 24a of the first basement floor B1 while being elastically deformable in the horizontal direction.

Then, as shown in FIGS. 9 and 10, the predetermined vertical streaks 37 are bent at their cut ends toward the inner surface or the outer surface of the outer wall 18a. Here, the vertical bar bent to the inner surface side or the outer surface side is referred to as a spare steel rod damper indicated by reference numeral 37a, and the vertical bar extending vertically downward without being bent is referred to as a steel bar damper indicated by reference numeral 37b.

Next, a plurality of steel pipes 38 into which the tips of the steel rod dampers 37b are inserted are fixed to the lower surface 35a of the opening 35. Next, on the outer circumference of the steel rod damper 37b located on the upper surface 35b side of the opening 35, a strip steel (deformation preventing member) 39 is formed so as to surround a plurality of the steel rod dampers 37b from the outer circumferential side.
To fix.

As described above, in the present embodiment, the existing building 10
The pit retaining wall 32 is constructed so as to surround the outer wall 18a of the first basement floor B1 and the isolator 34 which is installed in the middle of the outer pillar 26a of the first basement floor B1 and receives the vertical load of the existing building 10, The seismic isolation device is composed of a plurality of steel rod dampers 36b exposed from the inside of the outer wall 18a of the first floor B1. When an earthquake occurs, the isolator 34 elastically deforms in the horizontal direction with a predetermined displacement, and the steel rod damper 37b causes a bending plastic deformation in the horizontal direction with its tip end sliding inside the steel pipe 38. Then, the seismic force is promptly attenuated by absorption of the hysteresis energy due to the bending plastic deformation of the steel rod damper 37b, and the horizontal displacement amount of the existing building 10 above the first basement floor B1 is allowed within the pit retaining wall 32. Suppress to range.

In comparison with the conventional method of constructing a pit so as to surround the entire circumference of the lower part of the skeleton of the existing building, in the present embodiment, the pit holding only encloses the outer wall 18a of the basement B1 of the existing building 10. By constructing the wall 32, the period required for excavation of earth and sand and the period for constructing the retaining wall are short, so that the construction period can be shortened and the cost of seismic isolation work can be reduced.

Further, when the isolator 34 is installed in the middle of the outer pillar 26a, the outer wall 18a bears the vertical load of the existing building 10. Therefore, unlike the conventional method, a supporting device such as a hydraulic jack is unnecessary, and the isolator 34 is further removed. The cost of seismic work can be reduced.

Since the damper only utilizes the vertical streaks 37 exposed by crushing the concrete of the outer wall 18a, a simple seismic isolation device can be provided. Further, since the strip steel 39 arranged so as to surround the upper end side of the plurality of steel rod dampers 37b prevents plastic deformation of the upper end surface side of the steel rod damper 37b, when the steel rod damper 37b is plastically deformed. Moreover, the concrete of the outer wall 18a is not damaged. When the width of the steel strip 39 is changed, the plastic deformation area of the steel rod damper 37b increases or decreases, so that the hysteresis energy of the steel rod damper 37b can be adjusted.

Further, when the spare steel rod damper 37a whose cut end is bent is inserted into the steel pipe 38 fixed to the lower surface 35a of the opening 35 on the inner surface side or outer surface side of the outer wall 18a,
It can be used as a replacement steel rod damper.

Next, FIG. 11 shows a modification of the above-mentioned embodiment. In this embodiment, the underground 1
As a pre-stage of forming the installation space 36 in the outer column 26a of the floor B1, the column connecting device 40 is arranged so as to sandwich the position forming the installation space 36 from the vertical direction.

This column connecting device 40 is shown in FIGS.
As shown in FIG. 5, a pair of short upper fixing members 42a and 42b and a pair of lower fixing members 44a and 44 made of angle steel.
b and an elongated connecting member 46 made of angle steel. Then, the pair of upper fixing members 42a and 42b
Is fixed by inserting the anchor bolts 48 buried in the side surfaces orthogonal to each other above the formation position of the installation space 36 into the insertion holes formed in one side portion of the installation space and screwing a nut at the tip portion thereof. There is. Further, the pair of lower fixing members 44a and 44b are also inserted with anchor bolts embedded in side surfaces orthogonal to each other below the formation position of the installation space 36 through insertion holes formed in one side thereof, and a nut is attached to the tip portion thereof. It is fixed by screwing.

Further, the connecting member 46 has insertion holes formed at both ends in the longitudinal direction of the one side portion and the other piece portion. Here, the insertion hole 46a formed on the lower side has a long hole shape in which the long axis extends in the vertical direction.

The connecting member 46 includes a pair of upper fixing members 42a and 42b and a lower fixing member 44a.
One side portion and the other piece portion of 44b are brought into contact with the other piece portions close to each other of 44b, and the connecting bolt 50 is inserted into the corresponding insertion holes.
Is inserted, and a nut 52 is screwed into the tip end thereof to be connected to the pair of upper fixing members 42a and 42b and lower fixing members 44a and 44b.

The column connecting device 40 having the above structure is installed in the installation space 36.
If it is arranged so as to sandwich the formation position of from above and below,
Even if the installation space 36 is formed, since the vertical load of the existing building 10 is transmitted to the lower side of the outer pillar 26a through the pillar connecting device 40, a pillar supporting device such as a jack is not required, and FIG.
Therefore, unlike the embodiment shown in FIG. 10, it is not necessary to limit the formation position of the installation space 36 so that the outer wall 18a bears the supporting force.

Further, when the nut 52 screwed with the bolt 50 inserted into the long hole-shaped insertion hole 46a is loosened, the transmission of the vertical load to the column connecting device 40 is released, and the installation space 3 is installed.
The isolator 34 installed at 6 receives the vertical load of the existing building 10 while being elastically deformable in the horizontal direction. Then, when the column connecting device 40 is arranged with the nut 52 loosened, the connecting member 46 becomes the existing building 10 when the earthquake occurs.
It has a brace function that regulates the amount of horizontal displacement of the.

Therefore, when the column connecting device 40 is used, the installation space 36 in which the isolator 34 is installed can be easily formed, so that the cost of seismic isolation work can be reduced and the connecting member 46 has the brace function. Can be provided.

In the above embodiment, the seismic isolation device is installed on the pillar and wall on the first basement floor, but the gist of the present invention is not limited to this, and for example, the seismic isolation device is installed on the pillar and wall on the second floor above the ground. By installing a seismic device, it is possible to obtain the same effect by seismic isolation by reducing the rigidity of the upper floors of the third floor and above in the event of an earthquake.

Further, in the above-described embodiment, the isolator 34 is installed in the middle of the outer pillar 26a integrated with the underground outer wall 18, and the vertical bars 37 exposed by the crushing of a part of the concrete of the underground outer wall 18 are used as reinforcing bar dampers. However, the present invention is not limited to this. For example, when the isolator 34 is installed in the middle of the inner column 28a shown in FIG. 2 and the vertical bar 37 exposed by crushing part of the concrete of the inner wall 29a is used as a reinforcing bar damper, The effect of can be obtained.

[0035]

As described above, according to the first aspect of the present invention.
The seismic isolation method for the existing building described above uses a support device installed in the middle of a specific lower-floor pillar, and uses the vertical bars anchored to the concrete of the reinforced concrete wall on that floor as a steel rod damper. Therefore, when an earthquake occurs, the supporting device elastically deforms in the horizontal direction with a predetermined displacement, and the steel rod damper causes bending plastic deformation in the horizontal direction, and the earthquake energy is absorbed by the bending plastic deformation of the steel rod damper. Since the force is quickly attenuated, it is possible to reduce the rigidity of the upper floors above the specific lower floor when an earthquake occurs. As a result, the seismic isolation method for already constructed middle and low-rise buildings can be reliably performed.

Further, according to the present invention, since the supporting device such as a jack is not used when the supporting device is installed, and the vertical bar of the reinforced concrete wall is used as the steel rod damper, the conventional seismic isolation method is used. Compared with, the construction period and construction cost can be significantly reduced.

On the other hand, in the seismic isolation method for an existing building according to claim 2, a support device is installed in the middle of a pillar on the first basement floor, and
Since the vertical bars that were anchored in the concrete of the reinforced concrete wall on the first floor are used as steel bar dampers, when an earthquake occurs, the supporting device elastically deforms with a predetermined displacement in the horizontal direction, and the steel bar dampers The horizontal bending plastic deformation is caused, and the seismic force is promptly attenuated by absorbing the hysteresis energy due to the bending plastic deformation of the steel rod damper, so that the rigidity of the ground floor at the time of the earthquake can be reduced. As a result, the seismic isolation method for already constructed middle and low-rise buildings can be reliably performed.

Further, according to the present invention, since the ground around the first basement floor is excavated to construct the pit retaining wall, the period required for excavation does not form a large underground space unlike the conventional seismic isolation method. Since it is a short period and does not require a large number of construction materials, it is possible to omit the period required for loading and unloading of materials.
Therefore, it is possible to significantly reduce the construction period and construction cost as compared with the conventional seismic isolation method.

In both of the first and second aspects of the invention, when the spare steel rod damper is inserted into the steel pipe fixed to the lower surface of the opening, the damping force of the steel rod damper can be changed. In addition, it can be used as a replacement steel rod damper.

The invention described in claim 3 is the same as claim 1
Alternatively, the effect of the seismic isolation construction method for the existing building described in 2 can be obtained, and even if the steel rod damper is plastically deformed when an earthquake occurs, the deformation prevention member is fixed to the upper side of the steel rod damper. Does not damage reinforced concrete walls. Moreover, since the plastic deformation region of the steel rod damper changes when the vertical width of the deformation preventing member is changed appropriately,
The damping force of the steel rod damper can be changed.

The invention according to claim 4 is the same as claim 1.
The effect of the seismic isolation method for the existing building described in 3 to 3 can be obtained, and the vertical load transmission path of the existing building is secured by disposing the column connecting device. There is no need to limit the height position of the installation space formed in the middle of the pillar on the first basement floor. Therefore, the construction period can be further shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing an existing building made of reinforced concrete having a second basement floor.

FIG. 2 is a perspective view showing a specific underground structure.

FIG. 3 is a diagram showing a state in which a pit retaining wall is constructed by excavating the surrounding ground on the first basement floor.

FIG. 4 is a view showing a state in which a support device is installed in the middle of a pillar on the first basement floor.

5 is a view taken along the line VV of FIG.

FIG. 6 is a diagram showing a state in which concrete on the wall on the first basement floor is crushed to expose vertical streaks.

FIG. 7 is a view taken along line VII-VII of FIG. 6;

FIG. 8 is a diagram showing an overall structure in which a seismic isolation device is installed on the first basement floor.

FIG. 9 is a diagram showing a steel rod damper and vertical dampers each having a vertical bar.

10 is a view taken along line XX of FIG.

FIG. 11 is a view showing a state in which the column connecting device is arranged so as to sandwich an installation space in which the support device is installed.

FIG. 12 is a diagram showing a specific structure of a column connecting device.

FIG. 13 is a view taken along line XIII-XIII in FIG. 12;

[Explanation of symbols]

 10 existing building 14 ground 18a outer wall (wall) of the first basement floor 26a outer pillar (pillar) 28a inner pillar (pillar) 29a inner wall (wall) of the first basement floor 32 pit retaining wall 34 isolator (supporting device) 35 opening 36 installation Space 37 Vertical line 37a Preliminary damper 37b Steel rod damper 38 Steel pipe 39 Band steel (deformation preventing member) 40 Column connecting device 42a, 42b Upper fixing member 44a, 44b Lower fixing member 46 Connecting member 46a Long hole insertion hole

Claims (4)

[Claims] 1. A method for newly installing a seismic isolation device in an existing building of middle- and low-rise building, wherein an installation space for installing a support device is formed in the middle of a pillar on a specific lower floor, and the pillar bears the burden. The step of causing the vertical load of the existing building to be carried by the reinforced concrete wall of the specific lower floor, and the step of installing the supporting device that is elastically deformable in the horizontal direction in the installation space, The concrete of the wall of the specific lower floor is crushed to form an opening that opens in a slit shape in the horizontal direction, and in this opening, a plurality of vertical lines that have been fixed inside the concrete are exposed in the vertical direction. And a step of extending all of the plurality of vertical bars on the lower side to introduce a vertical load of the existing building into the supporting device, and a cutting end portion of a predetermined number of vertical bars is provided in the opening. Fixed on the underside of A number of steel pipes, the vertical bars inserted into these steel pipes are used as steel rod dampers that are plastically deformed by horizontal input when an earthquake occurs, and the remaining vertical bars are used as preliminary dampers. A seismic isolation method for existing buildings, which is characterized by that. 2. A method of newly installing a seismic isolation device in an existing building of a low-middle class having a basement floor, which is a process of excavating the ground around the first basement floor and constructing a pit retaining wall in the excavation space. And, in the middle of the pillar on the first basement floor, an installation space for installing a support device is formed, and the vertical load of the existing building, which was borne by the pillar, is carried by the reinforced concrete wall on the first basement floor. And a step of installing the supporting device that is elastically deformable in the horizontal direction in the installation space, and crushing the concrete of the wall of the first basement floor to form an opening that opens in a slit shape in the horizontal direction. Then, in this opening, a step of vertically extending a plurality of vertical streaks fixed inside the concrete in an exposed state, and cutting all of the plurality of vertical streaks on the lower side to support the support. Vertical load of the existing building to the device In addition to the above, the cutting ends of a predetermined number of vertical bars are inserted into multiple steel pipes fixed to the lower surface of the opening, and the vertical bars inserted into these steel pipes are input by horizontal input when an earthquake occurs. A method for seismic isolation of an existing building, characterized in that a steel rod damper that plastically deforms and a process that uses the remaining vertical bars as a preliminary damper are provided. 3. A step of fixing an upper side of the plurality of steel rod dampers extending in the vertical direction in the opening with a belt-shaped deformation preventing member having a vertical width set to a predetermined value. The method for seismic isolation of an existing building according to claim 1 or 2, characterized in that. 4. The pillar of the specific lower floor or the basement 1
As a step in the preceding step of the step of forming the installation space in the middle of the pillar of the floor, the upper position and the lower position of the pillar with the position where the installation space is formed, the vertical load of the existing building The seismic isolation method for an existing building according to any one of claims 1 to 3, further comprising a step of connecting with a pillar connecting device capable of transmitting.