JP6368551B2 - Seismic isolation method for existing buildings - Google Patents

Description

  The present invention relates to a seismic isolation method for an existing building to make the existing building a seismic isolation building.

The seismic isolation building is intended to make the upper structure seismic isolation by interposing a seismic isolation device between the upper structure and the lower structure.
As shown in FIG. 5A, the conventional seismic isolation building 100 is provided with a seismic isolation device 106 in a space (base isolation pit 105) surrounded by the base portion 103 of the lower structure 102 and the retaining wall 104. A base-isolated building that supports the upper structure 101 by the seismic isolation device 106 is generally used.
In the conventional base-isolated building 100, it is necessary to construct the upper structure 101 on the inner side of the site boundary line by the retaining wall 104 and the seismic isolation pit 105 of the lower structure 102.

In the middle floor seismic isolation building with the seismic isolation device installed on the middle floor of the building, the seismic isolation layer is required on the intermediate floor, but there is no need for retaining walls and seismic isolation pits, so that only the outer peripheral part Can be extended to the vicinity of the site boundary.
However, only the upper structure above the seismic isolation layer exerts the seismic isolation effect such as reducing the shaking at the time of earthquake in the intermediate floor seismic isolation building, and the substructure has almost no seismic isolation effect. In addition, when making existing buildings seismic isolation, it is often necessary to significantly reinforce the seismic isolation layer and the substructure, reducing the floor area due to column reinforcement and the area that cannot be used during the seismic isolation work. Become more.

  For this reason, Patent Document 1 discloses a renovation method in which a seismic isolation device is installed on a retaining wall and a seismic isolation pit is constructed between the retaining wall and the basement floor in an existing building where the building is built close to the site boundary. Proposed. As shown in FIG. 5B, the retaining wall 221 of the lower structure 220 is formed so as to surround the lower floor 211 of the upper structure 210, and the seismic isolation device 230 is attached to the upper end of the retaining wall 221. A seismic isolation building 200 is disclosed in which the outer peripheral portion of the upper floor 212 of the upper structure 210 is supported by a retaining wall 220 via the seismic isolation device 230. The seismic isolation building 200 is built up to the site boundary in a central city area or the like.

On the other hand, if an existing building is seismically isolated, the seismic isolation device increases the displacement of the superstructure during an earthquake, so the clearance around the building must be made larger than that of a non-seismic isolated building.
For this reason, existing buildings that are adjacent to adjacent land boundaries or adjacent buildings are moved horizontally in a direction away from the adjacent adjacent boundary lines, etc., by a distance that is greater than the clearance that is insufficient before and after seismic isolation. ) To secure a clearance with the adjacent boundary line or the like (see, for example, Patent Document 2).
In the construction of a base-isolated building (曳 家), the entire existing building is moved horizontally in a base-isolated pit with a foundation beam at the top and a pressure-resistant panel at the bottom.

  In the base-isolated building as shown in Patent Document 2 and FIG. 5 (a), the base portion of the lower structure that supports the upper structure is often a strong pressure-resistant panel or the like, and is moved horizontally by an amount equivalent to the insufficient clearance. There is almost no need to reinforce the substructure even when moving work is performed.

Japanese Patent No. 3340438 Japanese Patent No. 4199693

However, even if the upper structure is not supported by a strong pressure-resistant panel, even if it is a base-isolated building or a base-isolated building, it will move even if it is moved horizontally by the amount of insufficient clearance. As a result, the upper structure and the lower structure are displaced and an additional moment acts, so that it is necessary to reinforce the seismic isolation layer and the lower structure significantly. As the center of gravity acting on the column shifts, a large additional moment acts on the upper end of the column where the seismic isolation device is installed, so additional force is always applied to the column where the seismic isolation device is installed. .
In addition, since a large horizontal force acts on the upper end of the column that supports the load of the superstructure by installing a seismic isolation device, the lower end of the column is fixed only at the lower end. The power applied to will become enormous. In this case, since the force applied to the lower end portion is increased in proportion to the distance between the upper end portion and the lower end portion, the long pillar extending over a plurality of layers needs further reinforcement.

  In the middle-floor seismic isolation building that installs a seismic isolation device on the middle floor of the building and uses it as a seismic isolation layer, it is often necessary to significantly reinforce the seismic isolation layer and the substructure. Reinforce all the columns of the seismic isolation layer. There are many independent columns that are not continuous with the seismic wall, and the amount of reinforcement increases and the amount of reinforcement further increases when moved. In addition, the floor area is reduced by column reinforcement, and the area that cannot be used during the seismic isolation work increases.

  The retaining wall is for supporting earth pressure (lateral pressure). Generally, the earth pressure applied to the retaining wall increases proportionally from 0 at the ground surface position to the maximum value at the lower end.

Further, as shown in FIG. 5B, the lower structure 220 is formed so as to surround the lower floor 211 of the upper structure 210, and the intermediate floor base-isolated building is increased by increasing the proportion of the upper structure 210. Trying to reduce the disadvantages. In other words, the upper structure area that exerts the seismic isolation effect was increased, and the lower structure area that often required significant reinforcement was reduced. Moreover, when reinforcing the retaining wall 221 in order to mount the seismic isolation device 221 on the retaining wall, it is necessary to break the underground structure (lower floor 211) adjacent to the retaining wall 221, and the underground structure area is reduced.
If the seismic isolation layer has a step and is not a single plane, not only the clearance around the building (upper structure), but also the clearance between the upper structure and the lower structure must be carefully secured. In addition, a lot of seismic isolation clearance is required inside the building.

  From this point of view, the present invention constructs a seismic isolation building that effectively utilizes the site and does not violate the site boundary when isolating the existing building that is close to the adjacent building. The problem is to propose a method of seismic isolation for existing buildings.

In order to solve the above-mentioned problem, the seismic isolation method for an existing building according to the present invention separates the existing building into an upper structure and a lower structure and is erected along the outer edge of the lower structure. A step of adding concrete to the outer column, a step of providing a seismic isolation device between the outer column of the lower structure and the outer column of the upper structure, and a step of moving only the upper structure horizontally And . The concrete is placed on the outer column of the lower structure on the horizontal movement direction side of the upper structure with a thickness corresponding to the horizontal movement amount of the upper structure. In addition, the outer pillar of the lower structure and the outer pillar of the upper structure disposed on the side of the existing building are separated at a position higher than the ground surface , and the side is surrounded by the side The central part of the existing building is separated at a position lower than the ground surface. Further, the seismic isolation device is interposed between the outer column of the lower structure and the outer column of the upper structure at a position higher than the ground surface .
The upper structure may be moved after the seismic isolation device is interposed, or before the seismic isolation device is interposed.

According to the seismic isolation method for existing buildings, the upper structure is moved, so that it is necessary not only between the adjacent boundary line and the adjacent building, but also between the upper structure and the lower structure. It is possible to secure a seismic isolation clearance equivalent to that.
In addition, since the concrete is added to the outer pillar of the lower structure, the amount of eccentricity between the outer pillar of the upper structure and the outer pillar of the lower structure after movement can be minimized, The eccentric moment acting on the outer column of the structure can be minimized.
In addition, since the concrete is added to the outer column of the substructure, the retaining wall that surrounds the foundation mainly functions to support earth pressure, and the influence of the axial load is small. Is slight.

In addition, if the lower part of the existing building includes a side part facing the natural ground in the lower structure and a center part surrounded by the side part is included in the upper structure, the pit space is separately provided. There is no need to provide it, and the reduction of the floor area of the underground part of the existing building can be minimized.
The existing building may include an underground outer wall and an outer pillar provided in contact with the underground outer wall near a site boundary.

  According to the seismic isolation method of the existing building of the present invention, it is possible to prevent the floor area from being reduced by the seismic isolation pit structure, and to construct a base isolation building that effectively uses the site and does not invade the site boundary. Become.

(A) is sectional drawing which shows the seismic isolation building (building after movement) of this embodiment, (b) is AA sectional drawing of (a). (A) is sectional drawing which shows the building (existing building) before seismic isolation, (b) is sectional drawing which shows the building before a movement. It is an expanded sectional view which shows a part of building after isolate | separating into an upper structure and a lower structure. It is sectional drawing which shows the seismic isolation building which concerns on another form. (A) And (b) is sectional drawing which shows the conventional seismic isolation building.

The seismic isolation building 1 of the present embodiment is a seismic isolation of an existing building to which another building (adjacent building) B is adjacent.
As shown in FIG. 1, the seismic isolation building 1 includes an upper structure 2, a lower structure 3, and a seismic isolation device 4.

As shown in FIG. 2, the existing building 10 is a multi-storey building having four floors above ground, two underground floors, and a reinforced concrete ramen structure, but the size, shape, usage, and the like of the existing building 10 are not limited.
Moreover, the structural form of the existing building 10 is not limited. For example, the existing building 10 may be a reinforced concrete structure or a steel-framed reinforced concrete structure. The foundation of the existing building 10 may be a pile foundation or a direct foundation.

The seismic isolation method for an existing building according to the present embodiment includes a separation process, a step-up process, a seismic isolation device installation process, and a movement process.
The separation step is a step of separating the existing building 10 into the upper structure 2 and the lower structure 3 as shown in FIG. The existing building 10 is separated in a state where the upper structure 2 is provisionally received by a support member (not shown).

  At the outer edge of the existing building 10, as shown in FIG. 2B, the existing building 10 is vertically separated at a position higher than the ground surface GL. The outer pillar 11 (see FIG. 2A) formed along the outer edge (outer wall) of the existing building 10 is located between the outer pillar 30 of the lower structure 3 and the upper structure 2 at a position higher than the ground surface GL. Separated from the outer column 20. In this way, if the separation position is installed above the ground surface GL, there is no need to provide retaining walls and seismic isolation pits on the outer periphery of the building, and the outer periphery can be expanded to the vicinity of the site boundary line accordingly. desirable.

  On the other hand, the interior of the existing building 10 is separated in the underground part of the existing building 10 (position lower than the ground surface GL). Thus, in the separation step, the existing building 10 is configured so that the lower structure 3 includes the side facing the natural ground in the underground portion of the existing building 10 and the upper structure 2 includes the central portion surrounded by the side. Isolate.

The upper structure 2 includes a lower floor portion 21 formed by the center of the underground portion of the existing building 10 and an upper floor portion 22 formed by the ground portion of the existing building 10.
On the other hand, the lower structure 3 includes an underground floor portion 32 formed by a side portion of the underground portion of the existing building 10.

  The underground floor portion 32 of the present embodiment is seismically reinforced by adding concrete to pillars and beams for at least one span along the side facing the natural ground in the underground portion of the existing building 10. It is formed by separating from the central part.

A gap 42 is formed between the underground floor portion 32 and the lower floor portion 21. The gap 42 is formed to have a width larger than the assumed relative displacement at the time of the earthquake of the upper structure 2 with respect to the lower structure 3 after the movement.
In the present embodiment, the gap 42 on the opposite side (left side in the drawing) of the adjacent building B is made larger than the gap 42 on the adjacent building B side (right side in the drawing) of the lower floor portion 21. By doing so, both gaps 42 and 42 after the movement have a width larger than the assumed displacement at the time of the earthquake.

In the present embodiment, the base portion 31 of the lower structure 3 is formed below the existing building 10.
The foundation portion 31 is a concrete foundation slab newly formed below the lower floor portion 21. In addition, the structure of the foundation part 31 is not limited, For example, a foundation beam may be sufficient.

  The foundation portion 31 is formed by digging down the ground below the bottom of the existing building 10. The basic portion 31 of the present embodiment is formed in a concave shape in cross-section with the center being recessed from the periphery.

  The periphery of the foundation part 31 is in contact with the lower surface of the basement part 32 formed by the side part of the existing building 10, and supports the basement part 32 from below. In addition, the foundation part 31 should just be fixed integrally with the basement part 32, and the joining form (structure) with the basement part 32 is not limited.

As shown in FIG. 3, the additional striking step is a step of striking concrete on the outer column 30 erected along the outer wall 33 (outer edge) of the lower structure 3.
The thickness of the reinforced concrete 34 is not limited, and may be set as appropriate according to the amount of movement of the moving upper structure 2.

As shown in FIG. 2 (b), the reinforced concrete 34 to be struck to the outer pillar 30 standing on the adjacent building B side (right side in the drawing) is inside the building (opposite the adjacent building B). To be placed.
On the other hand, the reinforced concrete 34 to be struck by the outer pillar 30 erected on the opposite side (left side in the drawing) of the adjacent building B is laid on the outside of the building (the outer surface of the outer wall 33).

  In the present embodiment, as shown in FIG. 3, the inner pillar 35 and the outer pillar 30 that are erected with a space inside the outer pillar 30 (lower floor portion 22 side) as shown in FIG. And the beam 36 horizontally mounted on the inner pillar 35 is added.

  In the present embodiment, the inner column 35 is formed of reinforced concrete, but the configuration of the inner column 35 is not limited, and may be a steel column, for example. Further, the inner pillar 35 may be an existing pillar, or an existing pillar may be added and reinforced with cast concrete or the like.

  In the present embodiment, the beam 36 is formed of reinforced concrete, but the configuration of the beam 36 is not limited. Further, the beam 36 may be an existing beam, or may be an existing beam reinforced with reinforced concrete or the like.

The seismic isolation device installation step is a step of interposing the seismic isolation device 4 between the upper structure 2 and the lower structure 3.
The seismic isolation device 4 is provided between the outer column 20 of the upper structure 2 and the outer column 30 of the lower structure 3 and between the lower floor portion 21 of the upper structure 2 and the base portion 31 of the lower structure 3. (Seismic isolation pit 41).

In this embodiment, the seismic isolation apparatus 4 comprised by laminated rubber is used. In addition, the structure of the seismic isolation apparatus 4 is not limited, For example, a sliding bearing may be sufficient.
In this embodiment, in addition to the seismic isolation device 4, an oil damper (not shown) is also disposed between the upper structure 2 and the lower structure 3. What is necessary is just to set suitably the kind, number, arrangement | positioning, etc. of each apparatus used for seismic isolation.

The seismic isolation device 4 fixes the upper end to the upper structure 2.
As shown in FIG. 3, the seismic isolation device 4 interposed between the outer columns 20 and 30 fixes an upper end directly below the outer column 20 of the upper structure 2. At this time, the central axis of the seismic isolation device 4 is made to coincide with the column core of the outer column 20.

The upper end of the seismic isolation device 4 disposed in the seismic isolation pit 41 is fixed to the lower surface of the lower floor portion 21. In the present embodiment, as shown in FIG. 2B, a plurality of seismic isolation devices 4 are arranged in the seismic isolation pits 41 at equal intervals, but the number and arrangement of the seismic isolation devices 4 are limited. Not.
The lower end of the seismic isolation device 4 is fixed to the lower structure 3 (the outer column 30 or the base portion 31) after the upper structure 2 is moved.

As shown in FIG. 1, the moving process is a process of moving only the upper structure 2 horizontally (in a house).
The upper structure 2 moves horizontally in the direction opposite to the adjacent building B so that the clearance with the adjacent building B is increased. The amount of movement needs to be equal to or more than the clearance that is insufficient due to the seismic isolation, but since the outer column is seismic isolated, it must be less than the thickness in the direction of movement of the additional cast concrete 34 to the outer column. Therefore, since the amount of movement is not as large as in general house construction, in this embodiment, a moving method using sliding is used as a moving device instead of a roller bar or the like.
In general, the moving method using sliding is suitable for moving a large building with a high load, and is a method of installing a sliding device (moving body) under the foundation of the building. In the sliding device used in the mobile construction method, the area that contacts the sliding surface of one sliding material is large, and thus the load resistance per area in the sliding device is large. There is a feature that the reinforcement of the supporting foundation is also small.

Between the outer column 20 of the upper structure 2 and the outer column 30 of the lower structure 3, and between the lower floor portion 21 of the upper structure 2 and the base portion 31 of the lower structure 3 (seismic isolation pit 41) In addition, a sliding device (moving body) (not shown) is installed. Here, in the sliding device, a plate is fixed flatly on the upper surface of the lower structure 3 via a non-shrink mortar, and nylon excellent in sliding property is stuck on the contact surface on the upper structure side. The plate fixed to is provided movably.
Then, a horizontal movement jack (not shown) serving as a propulsion device is provided between the outer column 20 of the upper structure 2 and the outer column 30 of the lower structure 3 and the lower floor portion of the upper structure 2 as a sliding device at a predetermined location. It arrange | positions between 21 and the base part 31 of the lower structure 3 (seismic isolation pit 41), and can be pressed in a moving direction.

After the movement, an expansion joint is interposed between the lower floor portion 21 and the underground floor portion 32 (gap 42).
In addition, what is necessary is just to provide an expansion joint as needed.

According to the seismic isolation method of this embodiment, the following effects can be obtained.
That is, since the upper structure 2 is moved, a seismic isolation clearance corresponding to the displacement at the time of the earthquake by the seismic isolation device 4 can be secured between the adjacent building B and the interval between the adjacent buildings is close. Even when an existing building is seismically isolated (the outer wall is adjacent to the site boundary), it is possible to construct a seismically isolated building that effectively utilizes the site and does not invade the site boundary.

  In the middle-floor seismic isolation building that installs a seismic isolation device on the middle floor of the building and uses it as a seismic isolation layer, it is often necessary to significantly reinforce the seismic isolation layer and the substructure. Reinforce the pillar by striking it with more concrete. There are many independent columns that are not continuous with the seismic wall, and the amount of reinforcement increases and the amount of reinforcement further increases when moved. In addition, the floor area is reduced by column reinforcement, and the area that cannot be used during the seismic isolation work increases.

  Since the concrete is added to the outer pillar 30 of the lower structure 3, the amount of eccentricity between the outer pillar 20 of the upper structure 2 and the outer pillar 30 of the lower structure 3 after movement can be minimized. . Therefore, the eccentric moment acting on the outer column 30 of the lower structure 3 can be minimized.

  In addition, since concrete is struck at the position of the outer pillar 30 of the lower structure 3, compared with the conventional seismic isolation method that increases the wall thickness of the retaining wall that surrounds the foundation part of the building, it is troublesome during construction. And material costs can be reduced.

  While seismic isolation is not applied to the entire basement floor of the existing building 10 and only a part of the common space (lower floor part 21) is seismic isolated, the remaining common space (basement part 32) is seismically strengthened. It is used as a support for the seismic isolation building 1. Therefore, the remaining common space that becomes the basement portion 32 does not need to be changed in the same manner as the common space of the existing building 10, and the reduction in the floor area of the basement portion of the existing building 10 can be minimized. it can.

Since the living space is formed by the column beam frame formed by the outer column 30, the inner column 35 and the beam 36, the basement portion 32 can be effectively used.
In addition, since the earth pressure acting on the outer wall 33 is transmitted to the outer pillar 30, the wall thickness of the outer wall 33 can be suppressed to the minimum necessary.

The outer wall 33 is supported by a column beam frame and is stable against earth pressure.
In addition, since the upper structure 2 is supported by the outer pillars 30, a great earthquake horizontal force does not act on the outer wall 33, so that it is not necessary to increase the wall thickness of the outer wall 33 more than necessary.

Since the upper structure 2 is supported by the lower structure 3 via the seismic isolation device 4, the seismic isolation of the upper structure 2 is ensured.
Further, the gap 42 between the upper structure 2 (lower floor portion 21) and the lower structure 3 (basement floor portion 32) is larger than the relative displacement of the upper structure 2 with respect to the lower structure 3 during an assumed earthquake. Therefore, the upper structure 2 and the lower structure 3 are not in contact with each other at the time of an earthquake, and the seismic isolation function is not inhibited.

Since the lower floor portion 21 and the basement floor portion 32 are connected via an expansion joint, the lower floor portion 21 and the basement floor portion 32 can be always moved between the lower floor portion 21 and the basement floor portion 32, and the upper structure at the time of an earthquake, etc. The seismic isolation function of body 2 is not hindered.
Further, the planar shape of the lower structure 3 does not protrude from the planar shape of the upper structure 2, and the site can be used effectively.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the above-described components can be appropriately changed without departing from the spirit of the present invention.
For example, although the said embodiment demonstrated the case where a movement process was implemented after a seismic isolation apparatus installation process, the order of a seismic isolation apparatus installation process and a movement process is not limited. Moreover, although the said embodiment demonstrated the case where an additional punching process was implemented after a isolation | separation process, the order of a separation process and an additional punching process is not limited.

In the above embodiment, the upper end of the seismic isolation device 4 is fixed to the upper structure 2 before movement, and the lower end of the seismic isolation device 4 is fixed to the lower structure 3 after movement. The seismic device 4 may have its lower end fixed to the lower structure 3 before moving, and the upper end may be fixed to the upper structure 2 after moving, or the seismic isolation device is carried in and installed after the moving process is completed. May be.
The seismic isolation device 4 may be fixed to both the upper structure 2 and the lower structure 3 before moving. For example, when using a sliding bearing provided with a slide plate and a sliding member as the seismic isolation device 4, either the slide plate or the sliding member is used so that the axis of the seismic isolation device 4 after movement is vertical. One may be fixed to the upper structure 2 before movement and the other may be fixed to the lower structure 3.

In the embodiment, the case where the base portion 31 is newly provided as the lower structure 3 has been described, but the base portion 31 is not necessarily required to be newly provided.
For example, like the base-isolated building 1 shown in FIG. 4, the foundation slab 37 of the existing building 10 may be reinforced to be used as the foundation portion 31. In this case, the seismic isolation device 4 is interposed between the lower end of the pillar 23 of the lower floor portion 21 and the foundation portion 31. In addition, although the reinforcement method of the foundation slab 37 is not limited, For example, what is necessary is just to carry out by thickening by concrete, or adding a slab, a beam, etc.

  Although the said embodiment demonstrated the case where 1 span part of the underground part of the existing building 10 was used as the underground floor part 32 of the lower structure 3, the magnitude | size of the underground floor part 32 is not limited. Moreover, the use of the underground floor part 32 of the lower structure 3 is not limited.

  Moreover, the underground floor portion 32 of the lower structure 3 may be formed over the entire circumference of the underground portion of the building, or may be partially formed in the underground portion of the building. That is, the underground floor portion 32 may be formed on one of the left and right sides of the lower structure 3 and the other may be a retaining wall structure.

DESCRIPTION OF SYMBOLS 1 Base-isolated building 10 Existing building 2 Upper structure 20 Outer pillar 21 Lower floor part 22 Upper floor part 3 Lower structure 30 Outer pillar 31 Foundation part 32 Basement part 33 Outer wall 34 Reinforced concrete 35 Inner pillar 36 Beam 4 Seismic isolation Equipment 41 Seismic isolation pit 42 Clearance B Adjacent building

Claims (3)

Separating the existing building into an upper structure and a lower structure, and adding concrete to an outer column erected along the outer edge of the lower structure;
Inserting a seismic isolation device between the outer pillar of the lower structure and the outer pillar of the upper structure;
A step of horizontally moving only the upper structure, and a seismic isolation method for an existing building,
The concrete is placed on the horizontal movement direction side of the upper structure in the outer pillar of the lower structure with a thickness according to the horizontal movement amount of the upper structure,
The existing building surrounded by the side and separating the outer column of the lower structure and the outer column of the upper structure arranged at the side of the existing building at a position higher than the ground surface The central part of is separated at a position lower than the ground surface,
The seismic isolation device is interposed between an outer column of the lower structure and an outer column of the upper structure at a position higher than the ground surface , and is an isolation method for an existing building . Separating the existing building into an upper structure and a lower structure, and adding concrete to an outer column erected along the outer edge of the lower structure;
Horizontally moving only the upper structure;
A step of providing a seismic isolation device between the outer column of the lower structure and the outer column of the upper structure,
The concrete is placed on the horizontal movement direction side of the upper structure in the outer pillar of the lower structure with a thickness according to the horizontal movement amount of the upper structure,
The existing building surrounded by the side and separating the outer column of the lower structure and the outer column of the upper structure arranged at the side of the existing building at a position higher than the ground surface The central part of is separated at a position lower than the ground surface,
The seismic isolation device is interposed between an outer column of the lower structure and an outer column of the upper structure at a position higher than the ground surface , and is an isolation method for an existing building . 3. The method for seismic isolation of an existing building according to claim 1 , wherein the existing building includes an underground outer wall and an outer pillar provided in contact with the underground outer wall in the vicinity of a site boundary. .

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