JP5620462B2 - Seismic reinforcement method for existing buildings - Google Patents

Description

  The present invention relates to a seismic reinforcement method for an existing building having a reinforced concrete structure (RC structure) or a steel-framed reinforced concrete structure (SRC structure) ramen structure. The present invention relates to a seismic reinforcement method in which a beam of an existing building and a beam of a frame for seismic reinforcement are connected and reinforced.

Conventional seismic reinforcement methods generally reinforce existing structures. The most common method is the construction of shear walls or reinforced braces.
This method is often disliked because the open space becomes closed.
In addition, in order to ensure the toughness of the column, a method of winding a steel plate, a carbon fiber sheet, or the like, or the column cross section itself may be increased in order to ensure the strength of the column. The same applies to beams.
In the case of such seismic reinforcement by the prior art, construction is mainly performed inside the building, and construction while using the building is difficult. This puts a great burden on the user of the building and hinders the spread of seismic reinforcement.

Moreover, even if it is construction from the outside, if it is reinforced with a seismic wall and braces, construction can be performed while it is in the room, but lighting, appearance, and scenery from the inside after seismic reinforcement are problems.
In addition, a method for constructing a frame outside (Patent Document 1 and Patent Document 2) has also been proposed.

JP 2004-169504 A JP2007-138472

In the case of a method of constructing a frame outside, if the frame is RC, it is necessary to form a formwork.
Assembling the pillar formwork is relatively easy, but assembling the large beam formwork requires a lot of labor and, as a result, the workability is not very good.
In addition, for the connection between the outer frame and the existing building, a post-installed anchor or a fastening hole is required in the existing RC structure. In such construction, the column part is difficult to construct because the main and hoop bars are densely arranged.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a high-grade seismic performance to an existing building of RC frame structure with a lower construction cost and a smaller construction work amount. The purpose is to provide a seismic reinforcement method.

In order to achieve the above object, the seismic retrofitting method of the present invention constructs a seismic retrofit frame composed of a reinforcing column and a reinforcing beam along the outer wall of an existing building of a reinforced concrete structure or a steel reinforced concrete frame structure, Without joining the existing external column located on the outer wall and the reinforcing column of the seismic reinforcing frame, the existing external beam located on the outer wall and the reinforcing beam of the seismic reinforcing frame are joined. The seismic reinforcement frame is loaded with the horizontal force of the existing building so that the existing building is seismically reinforced, and the reinforcing columns constituting the seismic reinforcement frame are RC structures, and the reinforcing beams are steel structures. And the portion of the reinforcing column to which the reinforcing beam is connected is composed of the RC structure part and a steel pipe having a rectangular cross section covering the part, and the reinforcing beam is joined to the steel pipe by welding. Before being Is connected to the reinforcing pillars, elsewhere the reinforcing pillars, characterized in that it is covered with another steel pipe, separated and the steel pipe.

  According to the present invention, a seismic reinforcement frame composed of a reinforcing column and a reinforcing beam is constructed along the outer wall of an existing building, and the existing external beam and the reinforcing column are reinforced without joining the existing external column and the reinforcing column. Since the existing building and the seismic reinforcement framework are connected by joining the beams, an excellent seismic reinforcement effect can be obtained with low construction cost and a small construction work amount.

(A) is a front view of the existing building 10 and the seismic reinforcement frame 24, and (B) is a plan view of the outer wall of the existing building 10 and the seismic frame 24. It is a figure which shows the joining relationship of the existing external beam 14 and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the existing external beam 14 and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the existing external beam 14 and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the existing external beam 14 and the steel beam 22 for reinforcement. (A), (B) is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement, respectively. It is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement. It is a figure which shows the joining relationship of the pillar 20 for reinforcement, and the steel beam 22 for reinforcement. It is a schematic diagram of the reinforcement frame | frame in which the damping damper was integrated.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an elevation view showing a specific example of a building subjected to a seismic reinforcement method according to a preferred embodiment of the present invention.
1A is a front view of the existing building 10 and the seismic reinforcement frame 24, and FIG. 1B is a plan view of the outer wall of the existing building 10 and the seismic frame 24.
The building 10 in the illustrated example is a four-story school building having a reinforced concrete (RC) ramen structure. The building 10 has an RC frame composed of a reinforced concrete column (RC column) and a reinforced concrete beam (RC beam). FIG. 1 shows a column located on the outer wall of the RC column of the building 10. The external column 12 and the external beam 14 which is a beam located on the outer wall portion of the RC beam of the building 10 are shown. Further, a hanging wall 18 suspended from the lower side of the external beam 14 is shown.

The seismic reinforcement method according to the present invention is a method for applying seismic reinforcement to an existing building 10 having an RC structure or an SRC ramen structure.
The seismic strengthening method of the present invention constructs a seismic reinforcing frame 24 in the vicinity of an existing building 10 and connects the beams without connecting the columns, thereby seismically reinforcing the existing building 10. Is to be applied.
Therefore, in the specific example of FIG. 1, the existing external beam 14 is reinforced by providing a steel beam 22 tightly coupled to the existing external beam 14 along the outer surface of the existing external beam 14. The building 10 is seismically reinforced. That is, the horizontal force at the time of the earthquake is borne by the seismic reinforcement frame 24, and the existing building 10 is seismically reinforced.

In carrying out the present invention, the reinforcing steel beam 22 is not necessarily provided corresponding to all the external beams 14 of the building 10.
In the specific example of FIG. 1, other existing external beams 14 except for the existing external beam 14 located in the first span from the left of the existing building 10 are reinforced by the seismic reinforcement frame 24.
More specifically, the existing external beam 14 located in the second span from the left of the existing building 10 is the existing external beam 14 corresponding to the floor slabs of the second, third, and fourth floors, and the reinforcing steel frame of the seismic reinforcement frame 24. The beam 22 is connected.
In addition, the existing external beam 14 located in the third and fourth spans from the left of the existing building 10 is the existing external beam 14 corresponding to the floor slabs of the second and third floors, and the reinforcing steel beam 22 of the seismic reinforcement frame 24. Are linked.
In addition, the existing external beam 14 located on the fifth span from the left of the existing building 10 (the span located on the rightmost side) is the existing external beam 14 corresponding to the floor slabs of the second, third, and fourth floors, and a frame for seismic reinforcement. 24 reinforcing steel beams 22 are connected.

Further, the reinforcing columns 20 corresponding to those reinforcing steel beams 22 and supporting both ends of the reinforcing steel beams 22 are not necessarily provided corresponding to all the external columns 12 of the building 10, and The individual reinforcing columns 20 are not necessarily provided over the entire height of the external column 12 of the building 10, and in the specific example of FIG. 1, the two reinforcing columns 20 on the left and right sides extend to the floor slab on the fourth floor. The one reinforcing column 20 at the center of the left and right is only as high as the floor slab on the third floor.
Which existing external beam 14 is to be provided and the reinforcing steel beam 22 is provided, and at that time, the dimensions of each part of the reinforcing steel beam 22 such as beam formation are to be subjected to seismic reinforcement. It is determined as appropriate based on the analysis result of the seismic strength of the building 10.

In the seismic reinforcement method according to the present invention, the seismic reinforcement framework 24 is constructed close to the existing building 10 and the beams are connected without connecting the columns.
In this case, the seismic reinforcing frame 24 composed of the reinforcing pillar 20 and the reinforcing steel beam 22 is constructed for one layer, and the existing external beam 14 and the reinforcing steel beam 22 are connected. In this way, the seismic reinforcement frame 24 may be constructed one by one in the upward direction, and the existing external beam 14 and the reinforcing steel beam 22 may be connected one by one.
Alternatively, only the reinforcing column 20 may be completed in advance, the reinforcing steel beam 22 may be assembled to the reinforcing column 20, and then the existing external beam 14 and the reinforcing steel beam 22 may be connected.

In the present embodiment, an H-shaped steel is used as the reinforcing steel beam 22 constituting the seismic reinforcing frame 24.
As shown in FIG. 2, the H-shaped steel may be arranged such that the web 32 extends on a vertical plane and the flanges 34 at both ends extend on a horizontal plane. Or you may arrange | position so that the web 32 may extend on a horizontal surface and the flange 34 of both ends may extend on a vertical surface.

Various known structures can be used for joining the existing external beam 14 and the reinforcing steel beam 22 that constitutes the seismic reinforcing frame 24.
FIG. 2 to FIG. 5 are diagrams showing a joint structure between the existing external beam 14 and the reinforcing steel beam 22.
When the existing external beam 14 is RC, for example, as shown in FIG. 2, an indirect joining method using a post-construction anchor 40 can be used.
Further, as shown in FIG. 3, a frictional direct joining method using all screw bolts 42 (adhesive anchors) (all screw bolts penetrating the web 32 of the reinforcing steel beam 22) can be used.
Moreover, as shown in FIG. 4, the friction direct joining method using PC steel material 44 (PC steel material which penetrates the web 32 of the reinforcing steel beam 22 and the existing external beam 14) is mentioned.
Moreover, as shown in FIG. 5, you may make it join in a floor form.
2 to 5, reference numeral 46 denotes a headed stud, reference numeral 47 denotes a post-installed anchor, and reference numeral 48 denotes mortar or concrete filled between the existing external beam 14 and the reinforcing steel beam 22. ing.

Further, as shown in FIGS. 6 (A) and 6 (B), the reinforcing column 20 constituting the seismic reinforcing frame 24 may be a steel column (S structure). The steel column shown in FIGS. 6A and 6B is made of H-section steel.
Thus, making the reinforcing column 20 steel structure is advantageous in improving workability and shortening the construction period.
6A has a smaller dimension between the flanges at both ends than the width of the existing external column 12, and therefore the existing external column 12 and the flanges at both ends are Whereas the reinforcing pillars 20 are arranged apart from each other, the H-section steel constituting the reinforcing pillars 20 shown in FIG. 6B is a dimension between the flanges at both ends rather than the width of the existing external pillars 12. Therefore, the reinforcing column 20 is disposed in a state where the existing external column 12 enters between the flanges at both ends and the existing external column 12 and the web are close to each other, and the existing external beam 14 and the reinforcing steel beam 22 are The amount of mortar and concrete 48 filled in between is reduced.
Further, the reinforcing pillar 20 may be a reinforced concrete pillar (RC structure) as shown in FIG. In this case, the reinforced concrete column may be a precast reinforced concrete member or may be cast on-site. In the present embodiment, the reinforcing steel beam 22 extends through the reinforcing column 20. In FIG. 7, reference numeral 50 indicates a columnar main bar, and reference numeral 52 indicates a hoop line.
In this way, the reinforcement column 20 is made of RC, which is disadvantageous in that the construction period is slightly longer when compared with steel structure, but by using a member having the same mechanical characteristics as the existing column, seismic reinforcement This is advantageous for improving performance.

  Further, as shown in FIG. 8, the reinforcing column 20 may have a so-called concrete-filled steel pipe structure (CFT structure) configured by filling concrete into a steel pipe 54 having a rectangular or circular cross section. In FIG. 8, reference numeral 56 indicates a vertical diaphragm for transmitting stress between the reinforcing column 20 and the steel beam 22. In this case, the reinforcing column 20 may be a precast reinforced concrete member or may be cast on-site.

  Further, as shown in FIGS. 9 and 10, the reinforcing column 20 is an RC structure having a column main bar 50, and only the portion of the RC column to which the reinforcing steel beam 22 is connected is disposed inside the rectangular steel pipe 58. It is also possible to greatly improve the workability by adopting the structure positioned in the above, omitting the stirrup, and using the steel pipe 58 as a steel mold. In other words, the portion of the reinforcing column 20 to which the reinforcing steel beam 22 is connected is composed of an RC structure and a steel pipe 58 having a rectangular cross section covering the portion, and the reinforcing steel beam 22 is connected to the steel pipe 58. The reinforcing column 20 is connected by welding. In this case, the reinforcing column 20 may be a precast reinforced concrete member or may be cast on-site. In the case of on-site casting, a concrete formwork is assembled at a place other than the rectangular steel pipe 58.

Further, as shown in FIG. 11, the reinforcing column 20 is made of RC having a column main reinforcement 50, and the steel mold 58 serving as a reinforcing bar is not continued in the vertical direction, so that welding at the time of construction is omitted. It is also possible to improve the performance. In other words, the portion of the reinforcing column 20 to which the reinforcing steel beam 22 is connected is composed of an RC structure and a steel pipe 58 having a rectangular cross section covering the portion, and the reinforcing steel beam 20 is connected to the steel pipe 58. It is connected to the reinforcing column 20 by being joined by welding, and other portions of the reinforcing column 20 are covered with another steel pipe 59 separated from the steel pipe 58.
In this case, the reinforcing column 20 may be a precast reinforced concrete member or may be cast on-site. In the case of on-site casting, the concrete formwork is assembled so as to close the gap between the rectangular steel pipes 58 and 59.

Moreover, in this invention, it is good also as a junction part of a column beam as shown in FIG.
That is, in the reinforcing column 20 of FIG. 12, the portion of the reinforcing column 20 to which the reinforcing steel beam 22 is connected is the same as in FIG. 10, the RC structure portion and the steel pipe 58 having a rectangular cross section covering this portion. It consists of and.
The reinforcing steel beam 22 is made of H-shaped steel, and the flange 34 of the H-shaped steel is not joined to the column steel frame 22 of the reinforcing column 20, and only the H-shaped steel web 32 is connected to the column steel frame 22 of the reinforcing column 20. It is joined.
And the cane 60 is provided between the flange 34 of H-shaped steel and the steel pipe 58 (reinforcing column 20).
In this way, by joining the steel beam 22 only to the web 32 and inserting the cane 60, it is possible to reduce the welding effort of the joint.

Moreover, in this invention, it is good also as a junction part of a column beam as shown in FIG.
That is, the reinforcing column 20 shown in FIG. 13 includes an RC portion and a steel pipe 62 having a rectangular cross section covering the portion.
The reinforcing steel beam 22 is made of H-shaped steel, and the flange 34 of the H-shaped steel is not joined to the column steel frame 22 of the reinforcing column 20, and only the H-shaped steel web 32 is connected to the column steel frame 22 of the reinforcing column 20. It is joined.
And the damping damper 64 is provided in the shape of a cane between the H-shaped steel flange 34 and the steel pipe 58 (reinforcing column 20).
By inserting the damping damper 64 in this way, the existing building 10 can be seismically strengthened and at the same time, a damping structure can be obtained.

Further, in the seismic reinforcing frame 24 shown in FIG. 14, a steel beam 22a disposed at the height of the floor slab on the second floor and a steel beam 22b disposed at the height of the floor slab on the third floor. In between, a pillar-shaped damping damper 70 is installed, that is, a pillar-shaped damping damper is installed between steel beams adjacent vertically. As the stud-type seismic damper 70, for example, the one described in JP-A-7-317370 can be used.
Further, the steel beam 22c disposed at the height of the floor slab on the fourth floor is provided with a vibration damper 72, that is, the adjacent reinforcing columns 20 are inserted into the steel frame with the vibration damper 72 interposed therebetween. They are connected by a beam 22c. As the damping damper 72 inserted in the steel beam, for example, the one described in JP-A-7-207984 can be used.
As described above, by incorporating a vibration damper, which is an energy absorbing device, into the earthquake-resistant reinforcement framework 24, the earthquake resistance can be greatly improved.

  DESCRIPTION OF SYMBOLS 10 ... Existing building, 12 ... External pillar, 14 ... External beam, 20 ... Reinforcement pillar, 22 ... Reinforcement steel beam, 24 ... Seismic reinforcement frame

Claims (3)

Build a seismic reinforcement frame consisting of reinforcement columns and beams along the outer wall of an existing building of reinforced concrete structure or steel reinforced concrete frame structure,
Without joining the existing external column located on the outer wall and the reinforcing column of the seismic reinforcing frame, joining the existing external beam located on the outer wall and the reinforcing beam of the seismic reinforcing frame,
The horizontal force at the time of an earthquake is borne by the frame for seismic reinforcement, so that the existing building is seismically reinforced,
The reinforcing column constituting the seismic reinforcing frame is RC, and the reinforcing beam is steel.
The location of the reinforcing column to which the reinforcing beam is connected is composed of the RC part and a steel pipe having a rectangular cross section covering the part,
The reinforcing beam is connected to the reinforcing column by being joined to the steel pipe by welding ,
The other part of the reinforcing column is covered with another steel pipe separated from the steel pipe.
Seismic reinforcement construction method characterized by that. The steel beam consists of an H-section steel with a web and a flange,
The flange of the H-shaped steel is not joined to the steel pipe of the reinforcing column, and only the H-shaped steel web is joined to the steel pipe of the reinforcing column,
Providing a cane between the flange of the H-shaped steel and the steel pipe of the reinforcing column;
The seismic reinforcement method according to claim 1. The steel beam consists of an H-section steel with a web and a flange,
The flange of the H-shaped steel is not joined to the steel pipe of the reinforcing column, and only the H-shaped steel web is joined to the steel pipe of the reinforcing column,
A damping damper is provided in the shape of a cane between the flange of the H-shaped steel and the steel pipe of the reinforcing column.
The seismic reinforcement method according to claim 1.

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