JP2011026811A - Seismic strengthening method for existing building - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To support an existing building even when a column of an outer peripheral section is shear-fractured during earthquakes. <P>SOLUTION: A reinforcing post 16 is installed on the lateral surface 14N, on the side of an internal column 12, of the column 14 of the outer peripheral section of the existing building 10. The reinforcing post 16, which is constituted as a hollow steel-pipe column, is long enough to lead to an upstairs beam 20 from a floor slab 18 of the existing building 10. An upside flange 22 is provided at the upper end of the reinforcing post 16; a downside flange 24 is provided at its lower end; and mortar 26 is infilled between the beam 20 and the upside flange 22 and between the floor slab 18 and the downside flange. The internal column 12, which ranges from the floor slab 18 to an undersurface of the upstairs beam 20, is joined via joints 28C, 28D and 28E after its periphery is enclosed with a reinforcing steel plate 28 with a plate thickness T1 from a lateral side. Mortar 32 is infilled into the gap between the internal column 12 and the reinforcing steel plate 28. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a seismic reinforcement method for existing buildings.

  Existing buildings with insufficient earthquake resistance are generally reinforced with earthquake resistance by means such as increasing the number of columns and surrounding the columns with steel plates or carbon fibers. In particular, when the outer peripheral column of an existing building is reinforced by a conventional reinforcing method, the outer wall is affected, so a large-scale construction is required, and a long curing period is required.

At this time, when a wall girder type beam is adopted for the outer wall, the shear span ratio of the outer peripheral column is reduced, and the outer peripheral column is liable to be sheared, so that sufficient consideration is required.
For this reason, there is a demand for a seismic reinforcement method that is simple and has good workability.
Then, the earthquake-proof reinforcement method which reinforces an outer peripheral part column simply is proposed (patent document 1).

  According to Patent Document 1, as shown in FIG. 5, in an existing building 80 having a reinforced concrete ramen structure, a reinforcing column 86 is provided outside the outer peripheral column 82 along the outer wall surface of the outer peripheral column 82. Yes.

  The reinforcing column 86 is a so-called CFT column in which a concrete steel 88 is filled in the column steel frame 90, and is provided at a height that requires reinforcement according to the location of the existing building 80. The reinforcing column 86 and the outer peripheral column 82 are joined using the shear key 84 planted on the outer peripheral column 82 as an anchor and fixed to the concrete 88 of the reinforcing column 86.

  Further, on the outside of the outer peripheral beam 94, a steel beam 92 is laid in a horizontal direction between reinforcing columns 86 that need reinforcement according to the location of the existing building 80. Both end surfaces of the steel beam 92 are joined to side walls of the column steel frame 90 of the reinforcing column 86. Thereby, the outer peripheral column 82 of the existing building 80 is seismically reinforced.

  However, since the axial force is always transmitted to the reinforcing column 86 in the reinforcing method of Patent Document 1, there is a risk that the outer peripheral beam 94 and the reinforcing column 86 may be sheared together when a large earthquake occurs. Moreover, since the construction is performed outside the existing building 80, there is a boundary restriction with the adjacent land.

JP 2007-138472 A

  In view of the above facts, an object of the present invention is to provide a seismic reinforcement method capable of supporting a building even if an outer peripheral column is sheared and destroyed during an earthquake.

  The seismic reinforcement method for an existing building according to the invention of claim 1 is to surround the inner pillar provided inside the existing building with a reinforcing member divided in the vertical direction, and then join the divided positions. Reinforcing and reinforcing a side column of the outer peripheral column facing the internal column of the existing building by providing an auxiliary column to transmit axial force during an earthquake.

  According to the first aspect of the present invention, the inner pillar is surrounded and joined by the reinforcing member divided in the vertical direction to be seismically reinforced. Further, the outer peripheral column is seismically reinforced by providing an auxiliary column to which axial force is transmitted during an earthquake on the side surface of the outer peripheral column facing the inner column.

  Thereby, not only an internal pillar but an outer peripheral part pillar can carry out earthquake-proof reinforcement, without requiring the construction outside. At this time, it is not necessary to directly process the outer peripheral column, and only an additional column is added to the side surface facing the inner column, and the workability is good. As a result, existing buildings can be seismically strengthened in a short period of time.

  The invention according to claim 2 is the seismic reinforcement method for an existing building according to claim 1, wherein the auxiliary pillar has a length from a floor slab of the existing building to a beam on an upper floor, and an upper end of the auxiliary pillar. The upper part is provided with an upper flange to be joined to the beam supported by the outer peripheral pillar, and the lower end is provided with a lower flange to be joined to the floor slab, and the beam and the upper flange are joined. It is characterized in that a filler is filled between the portions and between the joint portion of the floor slab and the lower flange.

According to the second aspect of the present invention, the splint has a length from the floor slab of the existing building to the upper floor beam, and an upper flange is provided at the upper end of the spur post, and the lower end of the spur post The part is provided with a lower flange. A filler is filled between the joint between the beam and the upper flange, and between the joint between the floor slab and the lower flange.
As a result, the beam is supported by the auxiliary pillar via the filler.

  As a result, except during an earthquake, the load of the existing building is not transmitted to the auxiliary column due to the shrinkage of the filler, and the inner column and the outer column support the existing building as usual. On the other hand, during an earthquake, damage to the internal pillar is suppressed by the reinforcing member surrounding the internal pillar. In addition, even if the outer peripheral column is damaged, the accessory column replaces the outer peripheral column and continues to support the beam. Thereby, the collapse of the existing building is prevented.

  The invention according to claim 3 is the seismic reinforcement method according to claim 1 or 2, wherein the auxiliary pillar is a concrete-filled pillar filled with concrete inside.

  According to the third aspect of the present invention, the auxiliary column is a concrete-filled column in which concrete is filled.

  By making the supporting column a concrete-filled column, the supporting strength of the supporting column can be increased, and the seismic strength of the existing building can be increased.

  Since this invention is set as the said structure, even if an outer peripheral part column shears and breaks at the time of an earthquake, it can support the existing building.

It is a figure which shows the basic concept of the seismic reinforcement method of the existing building which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the auxiliary | assistant pillar which reinforces an outer peripheral part pillar in the seismic reinforcement method of the existing building which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the reinforced steel plate which reinforces an internal pillar in the seismic reinforcement method of the existing building which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the auxiliary | assistant pillar which reinforces an outer peripheral part pillar in the seismic reinforcement method of the existing building which concerns on the 2nd Embodiment of this invention. It is a figure which shows the basic concept of the seismic reinforcement method of the existing building of a prior art example.

(First embodiment)
As shown in FIG. 1, the seismic reinforcement method of the existing building which concerns on 1st Embodiment is a method which reinforces the pillar of the existing building 10 and raises seismic strength.
The pillars of the existing building 10 are roughly classified into two types, that is, an inner pillar 12 located inside the existing building 10 and an outer circumference pillar 14 located on the outer periphery. Both are reinforced concrete columns.

First, the reinforcement of the outer peripheral column 14 will be described.
Of the side surfaces of the outer peripheral column 14, a reinforcing column 16 is provided on the side surface 14 </ b> N facing the inner column 12.

  As shown in FIG. 2, the accessory column 16 is a hollow steel pipe column (outer dimension D), and is provided at a distance S from the side surface 14N of the outer peripheral column 14. The supporting pillar 16 has a length from the floor slab 18 of the existing building to the beam 20 on the upper floor.

  The external dimension D of the accessory pillar 16 and the distance S from the outer peripheral pillar 14 are determined from the strength required for the existing building 10 to secure the target earthquake resistance. That is, the value is determined by the shear strength of the existing outer peripheral column 14, the shear strength of the auxiliary column 16, the attachment position of the auxiliary column 16, and the like.

  The accessory pillar 16 is divided into two, an upper accessory pillar 16A and a lower accessory pillar 16B, which are joined by a joint portion 16C. An upper flange 22 is provided at the upper end portion of the upper accessory post 16 </ b> A, and the upper flange 22 and the upper floor beam 20 are joined by an anchor bolt 30. In addition, a lower flange 24 is provided at the lower end portion of the lower accessory column 16B, and the lower flange 24 and the floor slab 18 are joined by an anchor bolt 30.

  Mortar 26 is filled between the joint between the beam 20 and the upper flange 22 and between the joint between the floor slab 18 and the lower flange. Thereby, the supporting pillar 16 can support the beam 20 of the upper floor. The outer wall 38 of the existing building 10 is a wall beam (wall girder).

  Thus, by providing the auxiliary pillar 16 on the outer peripheral column 14, the outer peripheral column 14 can be seismically reinforced without the need to assemble a scaffold outside the existing building 10. Furthermore, it is not necessary to process the outer peripheral column 14 directly, and only the work of adding the auxiliary column 16 to the side surface 14N facing the inner column 12 is good, and the workability is good. Of the outer peripheral column 14, the corner column 15 is not provided with the additional column 16.

Next, reinforcement of the internal pillar 12 will be described.
As shown in FIG. 3, the inner column 12 is surrounded by a reinforcing steel plate 28 having a thickness T1 over a range from the floor slab 18 to the lower surface of the upper floor beam 20.

  The reinforcing steel plate 28 is divided into two, an upper reinforcing steel plate 28A and a lower reinforcing steel plate 28B, and each is further divided into two in the left-right direction so as to surround the inner column 12 from the side. The upper reinforcing steel plate 28A and the lower reinforcing steel plate 28B surround the inner column 12 from the side, and are then joined by joints 28C, 28D, and 28E.

In addition, plate | board thickness T1 is determined from the intensity | strength required in order to ensure the shear strength of the internal pillar 12, and the seismic strength which the existing building 10 makes a target.
A gap between the inner column 12 and the reinforcing steel plate 28 is filled with a mortar 32 with a thickness T2. As a result, the inner column 12 is seismically reinforced with the reinforcing steel plate 28.

  As explained above, by reinforcing each of the outer peripheral column 14 and the inner column 12, the load of the existing building 10 is not transmitted to the auxiliary column 16 by the contraction action of the mortar 26 except during an earthquake. The inner pillar 12 and the outer peripheral pillar 14 support the existing building 10 as usual. On the other hand, during an earthquake, damage to the internal column 12 is suppressed by the reinforcing steel plate 28 surrounding the internal column 14.

Further, even if the outer peripheral column 14 is damaged, the auxiliary column 16 continues to support the beam 20 instead of the outer peripheral column 14. Thereby, collapse of the existing building 10 is prevented.
This embodiment can be adopted for each floor of the existing building 10.

  In addition, since the internal column 12 does not have the required shear strength, the outer peripheral column 14 can be used when the existing building 10 cannot secure the target seismic strength even when the reinforcing steel plate 28 having the thickness T1 surrounds the periphery. In the same manner as described above, the auxiliary pillar 16 may be provided on the side wall of the inner pillar 12.

(Second Embodiment)
As shown in FIG. 4, in the seismic reinforcement method for an existing building according to the second embodiment, the auxiliary pillar 16 described in the first embodiment is used as a concrete-filled auxiliary pillar 36.

The concrete-filled supporting pillar 36 is filled with concrete 34 inside the supporting pillar 16. Thereby, the support strength of the pillar 36 with concrete filling can be increased. As a result, the seismic strength of the existing building 10 can be further increased.
Other configurations are the same as those of the first embodiment, and a description thereof will be omitted.

DESCRIPTION OF SYMBOLS 10 Existing building 12 Inner pillar 14 Outer peripheral pillar 16 Side pillar 18 Floor slab 20 Beam 22 Upper flange 24 Lower flange 26 Mortar (filler)
28 Reinforced steel sheet (reinforcing member)
34 Concrete 36 Concrete-filled pillar (concrete-filled pillar)

Claims (3)

After surrounding the internal pillars provided inside the existing building with the reinforcing members divided in the vertical direction, the divided positions are joined and reinforced,
A method for seismic reinforcement of an existing building, in which a side post of an outer peripheral column facing the internal column of the existing building is provided and reinforced by an auxiliary column to transmit axial force during an earthquake. The splint is the length from the floor slab of the existing building to the beam on the upper floor,
An upper flange to be joined to the beam supported by the outer peripheral pillar is provided at the upper end of the accessory pillar, and a lower flange to be joined to the floor slab is provided at the lower end.
The seismic reinforcement method for an existing building according to claim 1, wherein a filler is filled between a joint between the beam and the upper flange and between a joint between the floor slab and the lower flange.   The seismic reinforcement method for an existing building according to claim 1, wherein the auxiliary pillar is a concrete-filled pillar filled with concrete.

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