JP2003013614A - Seismic strengthening method for existing building, and brace mounting apparatus for use therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seismic strengthening method for an existing building, which can avoid damage to a skeleton of an existing frame, and seismically strengthens the existing frame without taking special strengthening procedures. SOLUTION: According to the method, in existing reinforced concrete framework, a leg portion plate 51 and a head portion plate 61 each having a gusset plate 7 on a front side thereof are fixed to a leg portion of one of columns 1 and to a head portion of the other column 1 which form the frame to be seismically strengthened, and a brace 4 is erected between the leg portion plate 51 and the head portion plate 61, followed by connecting both ends of the brace 4 to the respective gusset plates 7, 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for seismically strengthening an existing reinforced concrete structure in a structure, and a mounting device for mounting a brace used in the method.

[0002]

2. Description of the Related Art A method for seismically reinforcing an existing reinforced concrete structure in a structure is a method for disposing seismic walls in a frame of columns or beams and a method for disposing braces. Broadly divided.

In the method (1), the existing frame and the seismic wall are integrated with each other. In the method (2), the steel frame for connecting the ends of the steel brace is fixed along the inner circumference of the frame of the pillar / beam. Therefore, it is necessary to drive anchors such as chemical anchors into the concrete of columns and beams from the inner peripheral side of the frame, and holes larger than the diameter of the anchor itself will be drilled, so existing structure It can also damage and damage existing rebar.

According to the above method, the reaction force from the added earthquake-resistant wall, which bears the horizontal force at the time of earthquake, acts on the existing pillar / beam frame, so that the stress load on the frame partially increases. In some cases, it may be necessary to reinforce the frame, such as increasing the cross section of the frame. Therefore, the load on the existing frame is not always reduced while the seismic wall is added for the purpose of seismic strengthening. Also, due to the addition of earthquake-resistant walls, it becomes impossible to construct if the foundation and piles need to be reinforced due to the increased weight of the superstructure.

In the method of (1), if the steel frame is fixed to the pillar / beam frame by using an adhesive such as an epoxy resin filled between the two, the problem of damage to the skeleton when using the anchor can be avoided. However, since the steel frame member circulates along the inner periphery of the frame, the steel frame member is also laid on the slab.Therefore, although the braces are partially installed, the door should be provided in the frame after the seismic reinforcement. There is an inconvenience that you cannot do it.

In addition, when the floor height of the existing structure is largely restricted and the distance from the top of the slab on the lower floor to the lower end of the beam on the upper floor is not sufficient, a steel frame is placed in the frame. Since the inner height of the steel frame becomes small, the braces may not be installed at an appropriate angle.

From the above background, the present invention proposes a method for solving the problem of the conventional seismic strengthening method in a structure.

[0008]

According to the present invention, the existing reinforced concrete frame structure is reinforced by seismic reinforcement with braces, and the braces are connected to the legs and heads of the pillars with the beam ends removed. While avoiding damage, the seismic performance of the existing frame is secured without requiring special reinforcement.

Since the yield end hinge is easily formed at the end of the beam by an excessive load due to the horizontal force, reinforcement is required around the end of the beam when the end of the brace is connected to the end of the beam. By connecting braces to the legs and head, or both of the pillars, which have higher bearing capacity and higher durability, there is no need to provide extra reinforcement to the existing body, including the area around the pillars. The braces are also compatible with beam-less flat slab construction, as the braces do not need to be connected to the beams.

A leg plate having a gusset plate on the front surface side and a head plate are fixed to the leg of one column and the head of the other column to which the brace is connected. The leg plate and the head plate are fixed to the erection side of the brace, the brace is erected between the leg plate and the head plate, and both ends thereof are connected to the gusset plates.

Since the leg plate and the head plate may be fixed to at least the brace installation side of the pillar,
The plate itself is fixed independently, and is fixed to the pillar by using an anchor body fixed in the pillar as described in claims 2 and 10, for example.

When the brace is installed on both sides in one direction with the column interposed, the leg plate and the head plate are opposed to each other in at least one direction with the column interposed therebetween as described in claims 3 and 11. It is fixed to the pillar by inserting a tension material that penetrates the pillar between the leg plates and the head plate that face each other, and when the brace is installed in two directions on the plane, it is opposed in two directions. Are arranged.

When the leg plate and the head plate are arranged so as to face each other in two directions, they are assembled in a band plate shape so as to surround the column as described in claims 4 and 12. In this case, a gusset plate for connecting the ends of the brace is projected from the band plate surrounding the column to prevent damage to the column, and the band plate also surrounds the column to restrain the concrete. And has the effect of increasing yield strength.

As described in claim 9, the leg plate and the head plate constitute a mounting device for mounting the brace by forming a pair with the joint part of the column between the leg plate and the head plate sandwiched vertically.

The lower surface of the leg plate fixed to the leg portion,
Diaphragms contacting the slab top end surface and beam bottom end surface are joined to the upper surface of the head plate fixed to the head, respectively, and the leg plate and the head plate are connected to each other by a tension member penetrating each diaphragm and slab. , Unite.

At the column-beam joint where the mounting device is mounted, the vertical component of the tensile force from the brace is the tension between the leg plate on which the gusset plate is projected or the diaphragm joined to the head plate. It is transmitted to the beam or slab from the diaphragm of the head plate or leg plate facing each other through the material.

The horizontal component of the tensile force is transmitted to the column directly by the leg plate or head plate fixed to the column. When the leg plate and the head plate are arranged so as to face each other with the column interposed therebetween, as in claim 3 or 11, or the leg plate and the head as in claim 4 or 12. If the plate surrounds the post, it is transmitted from the leg plate and head plate to which the brace is connected to the post through the opposing leg plate and head plate.

The vertical component of the compressive force from the brace is transmitted to the slab or beam directly from the leg plate on which the gusset plate is projected, or from the diaphragm of the head plate, and the horizontal component is the leg plate, or It is transmitted to the pillar directly by the head plate.

Even in the case where the horizontal component of the tensile force from the brace is large and the leg plate or the head plate receives the force to separate from the column, in the cases of claims 2 and 10, the force is not generated in the column. The tensile force is applied to the column through the anchor body to be fixed, whereby the column structure according to claim 3,
In the case of 11, the tensile force is applied to the pillar from the facing leg plate or head plate through the tension material installed between the facing leg plates and the head plate, so that separation from the pillar is avoided. To be done. In the case of claim 3 and claim 11,
The tension members are optionally tensioned and the leg and head plates are crimped to the post.

When tension members are installed between the leg plates and the head plate that face each other in claims 4 and 12, the force acting to separate the tension plates from the columns acting on the leg plates and the head plate is applied. In contrast, the tensile material resists,
Even when the horizontal component of the tensile force from the brace is large, the effect of restraining the concrete by the leg plates and the head plate that circulate and the effect of increasing the yield strength by it are maintained.

Since the leg plate and the head plate mainly act to transmit the horizontal component to the column with respect to the tensile force and the compressive force from the brace, it is sufficient if they are in close contact with the outer peripheral surface of the column. When there is a possibility that slip occurs on the column when the vertical component acts, the inner peripheral surface of the leg plate and the head plate is formed into an uneven surface as described in claim 13, Filling material is filled between the inner peripheral surface of the head plate and head plate and the surface of the column, and frictional force and shear force are transmitted between the inner peripheral surface of the leg plate and head plate and the surface of the column. Connected as described. In this case, some of the vertical component of the force from the brace is transferred from the leg and head plates to the post.

Claims are required when the brace is installed between one of the leg portion and the head portion of the column and the middle portion of the beam, such as when installing a door in the column / beam frame to be reinforced. As described in 5, the beam gusset plate is fixed to at least one of the top end surface of the slab that connects to the beam on the lower floor side and the lower end surface of the beam on the upper floor side that constitutes the frame to be aseismic strengthened. . The brace is installed between one of the beam gusset plates and the leg plate or the head plate, and both ends thereof are connected to each gusset plate.

In the beam gusset plate, for example, steel members are installed on both sides of the beam as described in claims 6 and 7,
It is projected by using this steel frame member. The gusset plate for the beam on the top surface of the slab is projected on the upper flange of the steel member and the plate connected via the bolt penetrating the slab, and the gusset plate for the beam on the lower end surface of the beam is on the lower flange of the steel member. The plate is provided so as to be straddled between the plates.

The middle portion of the steel frame member is supported by the slab by connecting a bolt penetrating the slab to the upper flange of the steel frame member, and the ends thereof are the diaphragm of the leg plate and the head plate as claimed in claim 14. Is supported by the leg plate and the head plate by being connected to a receiving member installed between the diaphragm and the diaphragm.

In the case of claim 4 and claim 12, wherein the leg plate and the head plate surround the column, the end of the brace is fixed to the column via the leg plate and the head plate. Since it is possible to disperse and transmit the axial force of the brace to the pillar by connecting the pillars, it is possible to prevent local damage to the leg portion and the head portion of the pillar. If a brace-type damper with a damper built into the brace body is used, which generates a damping force when the frame is deformed and resists horizontal force as described in 8, the brace resistance is reduced Since it is transmitted, it is possible to avoid the action of an excessive load on the pillar, and at the same time, it is possible to absorb the energy at the time of the earthquake and suppress the sway of the frame at an early stage.

When using the brace type damper, the effect of avoiding the action of an excessive load on the body is exerted even when one end of the brace type damper is connected to a beam or a gusset plate for a beam connected to a slab. To be done.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, the invention according to claim 1 comprises a surface of a leg portion of one pillar 1 and a head portion of the other pillar 1 which constitute a frame to be reinforced against earthquakes. A leg plate 51 having a gusset plate 7 on its side and a head plate 61 are respectively fixed, a brace 4 is installed between the leg plate 51 and the head plate 61, and both ends thereof are connected to each gusset plate 7. It is a method to retrofit existing reinforced concrete frames.

[0028] A ninth aspect of the present invention is an attachment device for the brace 4 used in the seismic strengthening method of the first aspect.
The gusset plate 7 is fixed to the legs of the column, and the gusset plate 7 is projected on the surface, and the leg plate 51 to which the diaphragm 8 is joined on the lower surface and the head of the pillar 1 are fixed, and the gusset plate 7 is projected on the surface. At the same time, the head plate 61 having the diaphragm 9 joined to the upper surface thereof, the leg plate 51, the diaphragms 8 and 9 of the head plate 61 and the slab 3 are penetrated, and the two diaphragms 8 and 9 are connected to each other by pulling. Composed of wood 10.

In the following, the invention according to claims 4 and 12 is mainly assembled by assembling the leg plate 51 and the head plate 61 respectively as the leg band plate 5 and the head band plate 6 so as to surround the column 1. Details will be described with reference to FIGS.

1 to 3, the brace 4 is installed only between the leg band plate 5 of one of the adjacent columns 1 and 1 and the head band plate 6 of the other column 1. However, since the leg band plate 5 and the head band plate 6 sandwich the column / beam joint and are fixed to the column 1 in a pair in the upper and lower sides, the braces 4 and 4 are installed in the frame so that they cross each other. In some cases.

In FIGS. 1 and 7, the pillars 1 adjacent to each other in one layer 1
1 shows the case where a brace 4 is installed between the leg portion of one pillar 1 and the head portion of the other pillar 1, but for example, in a space where a slab is absent, between the adjacent pillars 1 and 1. In addition to installing the brace 4 over a plurality of layers, the brace 4 may be installed between the columns 1 and 1 over a plurality of spans in a plurality of layers.

The leg band plate 5 and the head band plate 6 which are paired and fixed to the column 1 constitute a mounting device for the brace 4 of claim 9 together with a tension member 10 which will be described later and connects the both.

FIGS. 1 to 3 also show the case where the frame is a reinforced concrete column / beam frame structure, but the present invention is basically a band plate 5 on the leg and head of adjacent columns 1 and 1. , 6 is fixed and the brace 4 is erected between the band plates 5 and 6, so that the shape of the existing reinforced concrete frame does not matter, and in the claim 1, since the brace 4 is not connected to the beam 2, It is also applied to the flat slab structure without the beam 2. 1 to 3, the slab 3 is omitted.

In addition to the reinforced concrete structure and the steel frame reinforced concrete structure, the structure type may be a mixed structure in which the beams 2 are made of reinforced concrete and the columns 1 are made of steel tube concrete, and both structures are combined.

In the drawing, when the frame is made of reinforced concrete, a damper 42 is provided on the brace body 41 as the brace 4 in order to reduce the resistance of the brace 4 in order to prevent the body from being damaged by the resistance of the brace 4. Brace type damper with built-in is used, but if measures are taken to prevent damage to the skeleton or there is little possibility of damage, brace 4 without damper 42 may be used. .

The brace type damper is composed of brace bodies 41, 41 which are relatively movable in the axial direction and a damper 42 incorporated in one of the brace bodies 41. The brace bodies 41, 41 have a tensile force acting between both ends thereof. The damper (42) generates a damping force when moving relative to each other by a compressive force, thereby suppressing the sway of the frame and reducing the resistance force to the frame. As the damper 42, in addition to an oil damper using a viscous fluid, a damper such as a friction damper that generates a damping force by relative movement in the axial direction is used.

In the case of an oil damper, a phase difference occurs between the response of the building at the time of an earthquake and the response of the damper 42, and the response of the damper 42 does not become maximum at the maximum response of the building, so the resistance acting from the brace 4 to the body is increased. The force is reduced compared to other types of dampers. In this case, by forming a flow path other than the piston in the cylinder and arranging a relief valve in the flow path,
Since the damping force can be controlled so as not to exceed a certain value, the resistance force can be further suppressed.

The leg band plate 5 and the head band plate 6 sandwich the joint between the pillar 1 and the beam 2, and are paired in the vertical direction and fixed to the pillar 1. In the drawing, both band plates 5 and 6
Shows a case where four leg plates 51 and a head plate 61 are respectively assembled in a box shape. However, since the shapes of the band plates 5 and 6 are determined according to the cross section of the existing column 1, a cylindrical shape or the like is used. Sometimes assembled in the form of.

When the leg plate 51 and the head plate 61 are assembled as the band plates 5 and 6, the leg plate 51 and the head plate 61 which are divided in the field are welded or the legs to be joined to each other. Part plate 5
1. A flange facing the head plate 61 is formed in advance, and both flanges are bolted to each other so that the pillar 1 is surrounded and assembled.

8 and 9, the horizontal component of the tensile force acting on the brace 4 is large, and the force for separating the leg plate 51 and the head plate 61 forming the band plates 5 and 6 from the column 1 is In case of working, the leg plates 51, 51 and the head plate 6 which face each other across the pillar 1 in at least one direction
A case where a reinforcing bar or a PC steel rod penetrating the column 1 or a tensile member 52 (62) such as a fiber reinforced material is inserted between 1 and 61 is shown.

FIG. 8 shows the case where the braces 4 are connected only in one direction, the tension members 52 (62) are arranged in three stages in that direction, and FIG. 9 shows the case where the braces 4 are connected in two directions. ,
This is a case where two layers are arranged in two directions in each direction.

A gusset plate 7 to which the end of the brace 4 is connected is joined to the side of the band plates 5 and 6 to which the brace 4 is connected. Placed in a well-balanced manner. In the drawing, two tension members 52 (62) are arranged on each side of the gusset plate 7.

In FIGS. 8 and 9, PC is used as the tension member 52 (62).
Using a steel rod, attach both ends of the tension member 52 (62) to the nuts 53, 53
(63, 63) are tightly connected to the front and back of the leg plate 51 (head plate 61). In this case, the leg plate
Since there is a gap between 51 (head plate 61) and the surface of pillar 1, non-shrink mortar is placed in the gap to prevent the deviation of leg plate 51 (head plate 61) and protect the surface of pillar 1. Filling material 11 such as epoxy resin or the like is filled. The filling material 11 is bored in the pillar 1 to obtain the adhesion between the tension material 52 (62) and the pillar 1, and is also filled in the through hole through which the tension material 52 (62) penetrates.

In FIGS. 8 and 9, as described above, the leg plate
The head plate 61 and the head plate 61 are assembled by orbiting around the pillar 1, and the band plates 5 and 6 are continuously formed in a box shape. However, FIGS. 11 and 12 are modifications of FIGS. 8 and 9, respectively.
In the case where the leg plates 51, 51 and the head plates 61, 61 are used independently and arranged so as to face each other with the column 1 sandwiched therebetween and connected by the tension members 52 (62) (claims 3 and 11). Show.

10 and 13 replace the tension member 52 (62) with the pillar 1
Anchor bolts and other anchor bodies that are fixed to the surface of the
(64) is used to fix each leg plate 51 and head plate 61 to the column 1. FIG. 10 shows a case in which the leg plate 51 and the head plate 61 are continuously assembled in a box shape as the band plates 5 and 6 (claims 4 and 12), and FIG. 13 shows the leg plates 51, 51 and the head. The case where the plates 61 and 61 are arranged so as to face each other with the column 1 in between and connected by the tension members 52 (62) (claims 3 and 11) is shown.

In the case of FIG. 10 and FIG. 13, the pillar 1 is viewed from the surface side of the pillar 1.
A cavity 1a that does not pass through is formed, the cavity 1a is filled with the filler 11 such as the non-shrink mortar or epoxy resin, and the anchor body 54 (64) is inserted. The filling material 11 is filled after forming the cavity 1a. The cavity 1a is divided into at least two sections on the front side and the back side in the depth direction, and the cross-sectional area of the back-side section is formed larger than the cross-sectional area of the front-side section.

As shown in FIG. 14, the cavity 1a has a cutting blade A at its tip.
After removing the concrete of the pillar 1 into a cylindrical shape by rotating the core tube B having a cylindrical shape, the peripheral portion of the cylindrical portion is formed into a cylindrical shape having a cutting blade C at the tip or the peripheral surface as shown in FIG. It is formed by rotating the bit D and crushing it into a truncated cone shape or a cylindrical shape.

The core tube B is connected to a drive shaft F1 of a drive unit F which is movably supported in an axial direction by a support member E temporarily fixed to the surface of the pillar 1, and after removing concrete into a cylindrical shape, it is driven. The attachment G eccentrically connected to the shaft F1 is connected to the tip of the drive shaft F1, and the shaft D1 of the bit D is connected to the attachment G.

The crushed concrete powder is eliminated by jetting air or by suction. After the cavity 1a is formed, the inside of the cavity 1a is filled with the filler 11, and the anchor body 54 (64) is inserted and fixed to the concrete of the pillar 1.

Leg band plate 5 (leg plate 51)
5 and the lower surface of the head band plate 6 (head plate 61) are orthogonal to the leg plate 51 and the head plate 61 as necessary to increase the rigidity of the band plates 5 and 6 as shown in FIG. The flanges 5a and 6a forming the surface are joined, and the rib plates 5b and 6b are joined in a direction orthogonal to the flanges 5a and 6a.

A gusset plate 7 for connecting the ends of the brace 4 is provided on the outer peripheral surface of any one of the leg plate 51 and the head plate 61, which constitute the band plates 5 and 6, to which the brace 4 is connected. To be done. When the gusset plate 7 is erected in the frame without the brace 4 crossing, as shown in FIGS. 2 and 4, the gusset plate 7 is provided so as to project in the center of the plate in the width direction (outward of the frame plane). When the braces 4 are installed to intersect with each other, they are provided so as to be offset in the width direction.

Leg band plate 5 (leg plate 51)
A diaphragm for contacting the top end surface of the slab 3 and the bottom end surface of the beam 2 on the bottom surface of the head band plate 6 (top plate 61) and transmitting a compressive force between the slab 3 and the beam 2. 8 and 9 are joined.

In the drawing, the force from the gusset plate 7 projecting at or near the center of the leg plate 51 and the head plate 61 forming the band plates 5 and 6 is passed through the diaphragms 8 and 9 to the slab 3 and the beam 2. The diaphragms 8 and 9 are formed in a circular shape with a large protruding length in the vicinity of the center of the plate so as to be sufficiently transmitted to the plate. However, the shape of the diaphragms 8 and 9 is not limited to this.

The gusset plate 7 is joined by welding or the like across the plates of the band plates 5 and 6 and the diaphragms 8 and 9 as shown in FIGS. 2 and 3, and the flanges 5a and 6a are attached to the band plates 5 and 6, respectively. When they are joined, they are also joined to the flanges 5a and 6a.

A long bolt or a PC is placed between the diaphragms 8 and 9 of the band plates 5 and 6 which are arranged in pairs vertically.
A tensile member 10 such as a steel rod is installed so as to penetrate through the slab 3 and a tensile force is applied to the tensile member 10 to fix both band plates 5 and 6 to the column 1. At this time, the diaphragm 8 of the leg band plate 5 is pressed onto the slab 3 and the diaphragm 9 of the head band plate 6 is pressed onto the beam 2. The tensile member 10 is evenly arranged in the circumferential direction of the diaphragms 8 and 9 at a position where the beam 2 is removed on the plane. In the drawing, tension members 10 are arranged on both sides of each beam 2.

If there is a gap between the inner peripheral surfaces of the band plates 5 and 6 and the surface of the column 1, and between the diaphragm 8 and the slab 3 and between the diaphragm 9 and the beam 2, there is a gap in terms of load transmission. Filling materials such as epoxy resin and non-shrink mortar 11
The band plates 5 and 6 are brought into close contact with the column 1, and the diaphragms 8 and 9 are brought into close contact with the slab 3 and the beam 2, respectively.

In FIG. 5, which is a vertical cross-sectional view of the beam end position of FIG. 4, the band plates 5 and 6 are connected to the column 1 so that the shearing force in the vertical direction can be transmitted between the band plates 5 and 6 and the column 1. A gap is formed between the inner peripheral surfaces of the band plates 5 and 6 and the surface of the column 1 when mounted around, and the inner peripheral surfaces are formed as the uneven surfaces 5c and 6c.

As shown in FIG. 7, the brace 4 is connected to one of the leg band plate 5 and the head band plate 6,
When the beam gusset plate 12 is installed between the middle portion of the beam 2 and at least one of the top end face of the slab 3 connected to the beam 2 and the lower end face of the beam 2, the beam gusset plate 12 is fixed.

In FIGS. 6 and 7, the gusset plate for this beam is used.
In order to fix 12 to the slab 3 and the beam 2, steel frame members 13 and 13 are installed on both sides of the beam 2. As shown in FIG. 5, the steel members 13 and 13 are tension members 10 that connect the diaphragms 8 and 9.
It will be installed at a position where it does not interfere with.

As shown in FIG. 5, the steel frame member 13 has a component from the diaphragm 9 located under the beam 2 to the lower end of the slab 3, and is sandwiched between the diaphragm 9 and the slab 3 at both ends to be attached to the diaphragm 9. Supported. In the middle part, as shown in FIG. 6- (b) which is a longitudinal sectional view of the beam middle part position of FIG. 4, the flange 13a and the slab 3 on the upper portion of the steel frame member 13 are shown.
It is partially supported by the slab 3 by bolts 14 that pass through it.

As shown in FIGS. 1 to 3 and 5, corresponding to the end of the steel frame member 13 between the lower surface of the diaphragm 8 of the leg band plate 5 and the upper surface of the diaphragm 9 of the head band plate 6. The receiving member 15 for stopping the end of the steel member 13 is installed at the position
Thirteen ends are connected and supported. The receiving member 15 is a tensile member
It penetrates through the slab 3 like 10 and is exposed under the slab 3.

In FIG. 2 to FIG. 5, chevron steel is used as the receiving member 15 for connecting the steel members 13 in the two directions, and the web 13b of the steel member 13 is joined to the receiving member 15 by the bolts 16. . When the stability of the angle steel is not ensured, as shown in FIG. 1, a T-shaped steel or a receiving member 15 in the form of a combination of plates in a cross shape is used.

The receiving member 15 overlaps the webs 13b and 13b of the bidirectional steel members 13 and 13 and is joined to both of them, but when the flanges 13a and 13a of the orthogonal steel members 13 and 13 interfere with each other, the flange 13a is formed. , 13a are cut off.

The upper and lower ends of the receiving member 15 are fixed to the lower surface of the diaphragm 8 and the upper surface of the diaphragm 9 directly or indirectly via a spacer 17 by welding or the like as shown in FIGS. The upper end of the receiving member 15 is fixed to the diaphragm 8 in advance, and the lower end thereof is fixed to the diaphragm 9 after the band plates 5 and 6 are installed.

As shown in FIG. 7, a beam gusset for connecting the end of the brace 4 to the position where the brace 4 is to be installed on the top end face of the slab 3 on the beam 2 or the lower end face of the beam 3. A plate 18 is arranged on which the plate 12 is projected.

The plate 18 arranged on the top end surface of the slab 3
As shown in Fig. 6, the upper flanges of both steel members 13, 13
It has a width across 13a, 13a and is joined to the slab 3 together with the upper flanges 13a, 13a by, for example, a bolt 14 penetrating the slab 3 described above.

The plate 18 arranged at the lower end surface of the beam 2 has a width across the lower flanges 13a, 13a of the two steel frame members 13, 13 and overlaps the lower flanges 13a, 13a of the two steel frame members 13, 13. It is joined by the bolt 19.

In FIG. 6- (b), the plate 18 arranged on the top end surface of the slab 3 and the plate 18 arranged on the lower end surface of the beam 2 are shown.
Are fixed in the same position, but the plate 18 on the slab 3
The plate 18 under the beam 2 is not necessarily arranged at the same position, and as shown in FIG. 7, they are arranged independently according to the installation position of the brace 4 in each of the upper layer frame and the lower layer frame. .

In order to eliminate the need to reinforce the beam 2 due to the installation of the brace 4, the plate is placed at a position excluding the end of the beam 2.
Although it is preferable to dispose the plate 18, it is necessary to dispose the plate 18 at the end position of the beam 2 because the leg band plate 5 and the head band plate 6 are located at the position corresponding to the end part of the beam 2. Absent.

16 and 17, the plate 18 on which the beam gusset plate 12 is provided in a projecting manner is anchored to the upper end side or the lower end side of the beam 2 as in FIG. 10 and FIG. The case where it is fixed to the beam 2 using 18a is shown. Figure 1
6 and 17 show the case where the plate 18 is fixed to the upper end of the beam 2, the same applies to the case where it is fixed to the lower end.

Also in this case, a cavity 2a which does not penetrate the beam 2 from the upper end side or the lower end side of the beam 2 and in which the cross-sectional area of the rear side section is larger than the cross-sectional area of the front side section is formed, and there is no cavity 2a. Filling material 11 such as shrink mortar or epoxy resin is filled, and anchor body 18a is inserted. The filling material 11 is filled after the cavity 2a is formed. A filler 11 is filled between the plate 18 and the surface of the beam 2 to prevent the plate 18 from slipping and to protect the surface of the beam 2.

When a cavity 2a having a large cross-sectional area on the back side is formed in the beam 2 and the anchor body 18a is fixed, as shown in FIG. 17, a portion having a large cross-sectional area is formed behind the upper end main bar 2b of the beam 2. By doing so, the upper end main bar 2b acts so as to restrain the filling material 11 against the pulling force that is exerted on the filling material 11 in the cavity 2b by acting on the anchor body 18a. There are high advantages.

FIG. 7 shows a case where the brace 4 is erected in a V shape by utilizing the beam gusset plate 12. In the upper frame, the head band plates 6 of the columns 1, 1 on both sides
The gusset plates 7 and 7 projecting on the 6 and the beam gusset plate 12 projecting on the top end of the slab 3 at the central position of the beam 2 on the lower floor are used. A gusset plate for a beam 12 protruding from the lower end of the beam 2 on the upper floor and a gusset plate for a beam protruding on the slab 3 on the lower floor to secure an opening near the columns 1 and 1. 12
Are using.

As in the lower frame of FIG. 7, a brace-type damper as a brace 4 is arranged close to the columns 1, 1 on both sides or one column 1 to increase the rigidity of both ends and one end of the beam 2. When the rigidity of the region where the brace 4 is absent is relatively reduced, the effectiveness of the damper 42 of the brace body 41 may be reduced. In that case, beam 2
For the purpose of ensuring the rigidity of the slab 3, the beam gusset plates 12 and 12 projecting above the lower slab 3 and below the upper slab 2 are used, and the stud 20 is provided between the slab 3 and the beam 2. Will be placed. Stud
20 is connected to both beam gusset plates 12 and 12 in a state in which substantially no bending moment is transmitted.

A partition wall is provided in the area where the brace 4 is installed.
21 is installed to avoid exposing the brace 4.

To both ends of the brace 4, brackets 43, 43 having a shape for sandwiching the gusset plate 7, for example, are connected. The brace 4 uses the gusset plates of the leg band plate 5 and the head band plate 6 in the brackets 43, 43. 7 and the beam gusset plate 12 are sandwiched, and they are connected by bolts, pins 44 and the like penetrating the both.

If the bracket 43 and the gusset plate 7 are detachably connected, it is possible to freely change the installation position of the brace 4 and replace the brace 4. For example, when the layout of the brace 4 needs to be changed due to a change in the floor plan after the seismic reinforcement, the brace 4 is separated from the leg band plate 5 and the gusset plate 7 of the head band plate 6 and installed in the same frame. Reassembled or incorporated into another frame.

[0078]

[Effects of the Invention] Since the existing reinforced concrete frame structure is reinforced by seismic reinforcement with braces and the braces are connected to the leg and head of the column, which has a higher proof strength than the beams, damage to the frame of the existing frame is avoided and special reinforcement is made. The seismic performance of the existing frame can be secured without requiring

In the second and the tenth aspects, the leg plate and the head plate are fixed to the column by using an anchor body fixed in the column, and in the third and the eleventh aspects, the legs opposed to each other with the column interposed therebetween. When the tension component from the brace is large by inserting the tension material that penetrates the column between the part plates and the head plate, and the leg plate and the head plate receive the force to separate from the column In addition, since the tensile force can be applied to the column through the anchor body and the tension member, the leg plate and the head plate can be prevented from being separated from the column.

In claim 4 and claim 12, since the leg plate and the head plate are assembled together by surrounding the column, damage to the column is avoided, and by surrounding the column, the concrete is restrained and the strength is increased. Has the effect of increasing

In particular, when the tension member is installed between the leg plates and the head plate which face each other in claims 4 and 12, the force for separating from the column acting on the leg plate or the head plate. Since the tensile material resists against the above, even if the horizontal component of the tensile force from the brace is large, it is possible to maintain the effect of concrete confinement by the leg plates and head plate that circulate and the effect of increasing the yield strength due to it. .

According to claims 5 to 7, the beam gusset is provided on at least one of the top end surface of the slab that is connected to the beam on the lower floor side and the lower end surface of the beam on the upper floor side, which constitutes the frame to be quakeproof. Since the plate is fixed and the brace is installed between one of the beam gusset plates and the band plate, a door can be installed in the frame, etc.
The degree of freedom in use can be increased while the frame is reinforced against earthquakes.

According to the eighth aspect of the present invention, by using a brace type damper in which a damper is incorporated in the brace body, which is a type that resists horizontal force while generating a damping force when the frame is deformed, the brace resistance is alleviated. Since it is transmitted to the pillar, it is possible to avoid the action of an excessive load on the pillar, and at the same time, it is possible to absorb the energy at the time of the earthquake and suppress the sway of the frame at an early stage.

In the ninth aspect, the leg plate and the head plate are assembled together by surrounding the column.
The leg and head that sandwich the joint with the beam form a pair, surround the column, and connect the leg band plate and head band plate with a certain height to each other with a tensile member, so the axial direction of the brace The force can be dispersed and transmitted to the columns, and the concentration of stress on the body can be avoided.

In the thirteenth aspect, since the inner peripheral surfaces of the leg plate and the head plate are formed into uneven surfaces and the filling material is filled between the inner peripheral surface of the band plate and the surface of the pillar, Friction and shear forces can be transmitted between the inner peripheral surface of the head plate and the outer peripheral surface of the column, preventing slippage between the leg plate and the head plate, and reducing the vertical component of the force from the brace. Parts can be transferred from the leg plate and head plate to the post.

In claim 14, since the receiving member is installed between the diaphragm of the leg plate and the diaphragm of the head plate, the top end face of the slab connected to the beam on the lower floor and the beam on the upper floor are connected. The gusset plate for a beam can be fixed at any position on at least one of the end faces, and it is possible to cope with seismic reinforcement while increasing the degree of freedom in use of the frame.

[Brief description of drawings]

FIG. 1 is a perspective view showing an installation situation of braces in a frame.

FIG. 2 is a perspective view showing an engagement between a leg band plate and a brace at a column / beam joint position.

FIG. 3 is a perspective view showing an engagement between a head band plate located under a slab and a brace.

FIG. 4 is a plan view showing the relationship between columns and band plates.

5 is a sectional view taken along line xx of FIG.

FIG. 6A is a plan view showing an example of projecting a beam gusset plate at an intermediate position of the beam, and FIG. 6B is a sectional view of FIG. 6A.

FIG. 7 is an elevational view showing a state in which a brace is installed using a band plate gusset plate and a beam gusset plate.

FIG. 8 (a) shows a case where a leg member (head plate) is assembled as a band plate and a tension member is inserted between the leg plates (head plate) facing each other in one direction. A cross-sectional view, (b) is an elevation view of (a).

FIG. 9A shows a case where a leg member (head plate) is assembled as a band plate and a tension member is inserted between the leg plates (head plate) facing each other in two directions. A cross-sectional view, (b) is an elevation view of (a).

FIG. 10 is a transverse cross-sectional view showing a case where a leg plate (head plate) is fixed to a column by using an anchor body instead of the tension member in FIG.

FIG. 11 (a) shows a case where the leg plates (head plates) are arranged so as to face each other, and a tension member is inserted between the leg plates (head plates) facing each other in one direction. The cross-sectional view is shown, and (b) is an elevation view of (a).

FIG. 12 (a) shows a case where the leg plates (head plates) are arranged so as to face each other, and a tension member is inserted between the leg plates (head plates) facing each other in two directions. The cross-sectional view is shown, and (b) is an elevation view of (a).

FIG. 13 is a transverse cross-sectional view showing a case where the leg plates (head plates) are individually opposed to each other, and the leg plates (head plates) are fixed to the columns using anchor bodies. .

FIG. 14 is an elevation view showing a formation state of a cylindrical portion of a cavity.

FIG. 15 is an elevational view showing a formation state of a portion on the far side of the cavity.

FIG. 16 is a perspective view showing an example of fixing a plate on which a beam gusset plate is projectingly mounted to the beam.

17 is a vertical cross-sectional view of FIG.

[Explanation of symbols]

1 ... Pillar, 2 ... Beam, 3 ... Slab, 4 ... Brace,
41 …… Main body, 42 …… Damper, 43 …… Bracket, 44…
… Pins, 5 …… Leg band plate, 51 …… Leg plate, 5a …… Flange, 5b …… Rib plate, 5c …… Rough surface, 6 …… Head band plate, 61 …… Head plate,
6a …… flange, 6b …… rib plate, 6c …… uneven surface,
51,61 …… Plate, 52,62 …… Tensile material, 53,63 …… Nut, 54,64 …… Anchor body, 7 …… Gusset plate, 8,9 …… Diaphragm, 10 …… Tensile material, 11 ...... Filling material, 12 …… Beam gusset plate, 13 …… Steel member,
13a ... flange, 13b ... web, 14 ... bolt, 15
…… Receiving member, 16 …… Bolt, 17 …… Spacer, 18 ……
Plates, 19 ... bolts, 20 ... studs, 21 ... partition walls, 1a ... (column) cavities, 2a ... (beams) cavities, 2b ......
Upper main bar, 18a …… Anchor body, A …… Cutting blade, B ……
Core tube, C ... Cutting blade, D ... Bit, D1 ...
Shaft, E ... Support member, F ... Drive device, F1 ... Drive shaft,
G: Attachment.

Claims (14)

[Claims] 1. In an existing reinforced concrete frame structure, a leg plate having a gusset plate on the surface side and a head plate are provided on the leg of one of the columns and the head of the other of the columns that constitute the frame to be seismic-proofed. A seismic retrofitting method for existing buildings in which braces are installed between the leg plates and head plates, and both ends are connected to each gusset plate by fixing each. 2. The method for seismic retrofitting an existing building according to claim 1, wherein the leg plate and the head plate are fixed to the pillar by using an anchor body fixed in the pillar. 3. A leg plate and a head plate are arranged so as to face each other in at least one direction across a column, and a tension member penetrating the column is inserted between the leg plates facing each other and the head plate. The seismic retrofitting method for an existing building according to claim 1, wherein the part plate and the head plate are fixed to the pillar. 4. The seismic retrofitting method for an existing building according to claim 1, wherein both the leg plate and the head plate are assembled by surrounding a column. 5. A beam gusset plate is fixed to at least one of a top end face of a slab connected to a beam on the lower floor side and a lower end face of the beam on the upper floor side, which constitutes a frame to be seismic-proof reinforced, and The existing building according to any one of claims 1 to 4, wherein a brace is installed between the beam gusset plate and the leg plate or the head plate, and both ends thereof are connected to each gusset plate. Seismic retrofit method. 6. A beam gusset plate for a slab top end surface is provided on a plate connected to both sides of a beam, and a plate connected to the upper flange of the steel member via a bolt penetrating the slab. 5. Seismic retrofitting method for existing buildings described in 5. 7. The beam gusset plate of the beam lower end surface is projectingly provided on the lower flange of the steel frame member on both sides of the beam, and on the lower flange of the steel frame member. Seismic retrofitting method for existing buildings. 8. The seismic strengthening method for an existing building according to claim 1, wherein the brace is a brace type damper in which a damper is incorporated in a brace body. 9. A brace mounting device used in the seismic retrofit method according to claim 1, wherein the brace mounting device is fixed to a leg portion of a column, and a gusset plate is projected on the surface of the bracing device. , A leg plate having a diaphragm joined to the lower surface, a head plate fixed to the head of the column, a gusset plate protruding from the surface, and a diaphragm joined to the upper surface, the leg plate and the head A seismic reinforcement brace mounting device that consists of a tensile member that penetrates each diaphragm and slab of the plate and connects both diaphragms to each other. 10. The leg plate and the head plate are fixed to the pillar by using an anchor body fixed in the pillar.
Installation device for the brace for earthquake-proof reinforcement described. 11. The leg plate and the head plate are arranged so as to face each other in at least one direction with a column interposed therebetween, and a tension member penetrating the column is inserted between the leg plates facing each other and the head plate. The seismic strengthening brace attachment device according to claim 9, wherein the part plate and the head plate are fixed to the column. 12. The seismic strengthening brace attachment device according to claim 11, wherein the leg plate and the head plate are both assembled to surround a column. 13. The inner peripheral surface of the leg plate and the head plate is formed into an uneven surface, and a filler is filled between the inner peripheral surface of the leg plate and the head plate and the surface of the column. The seismic reinforcement brace mounting device according to any one of claims 9 to 12. 14. The receiving member to which the steel frame members installed on both sides of the beam are connected is provided between the diaphragm of the leg plate and the diaphragm of the head plate. An installation device for the brace for seismic reinforcement according to any one of the above.