JP3228705B2 - Seismic retrofitting method for existing reinforced concrete buildings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic retrofitting method for an existing reinforced concrete building, and more specifically, to perform seismic retrofitting from the outside of a building without removing windows, waist walls, sagging walls, etc. of the existing building. The present invention relates to a seismic retrofitting method capable of securing a feeling of opening of a window portion, having an excellent aesthetic feeling, and enabling short-term construction.

[0002]

2. Description of the Related Art When an existing reinforced concrete building having an opening such as a window, such as a school building or an office building, is to be seismically reinforced later, a brace is provided for a window having a low strength or rigidity. It is often reinforced by incorporating it into a V-shape.

[0003] The reinforcing method has been conventionally performed in the following manner. First, in the region of the frame 20 on each floor having a size surrounded by a two-dot chain line in FIG. 10, an opening 31 from which a waist wall, a back wall, and a window are removed as shown in FIG. 7A is provided. As shown in FIG. 7 (b), a steel frame is formed by a vertical member 32 and a horizontal member 33 of an H-shaped steel so as to be inserted into a rectangular region surrounded by the pillar 3 and the beam 5 so as to be incorporated in the opening 31. A frame 34 is manufactured, and the braces 7, 7 are preliminarily incorporated therein as reinforcing materials so as to form a V-shape, whereby a steel frame assembly 35 is manufactured. And it welds so that many studs 8 may be arranged in the outer peripheral part of the steel frame.

The brace 7 is also made of H-shaped steel, but the flange portion 7b is arranged parallel to the vertical surface formed by the steel frame assembly 35 so as to have a strong axis in a direction perpendicular to the paper surface.
That is, care is taken to prevent the buckling in the out-of-plane direction by arranging the web portion 7a perpendicular to the vertical surface. The reinforcement in the in-plane direction is provided by a support member 36 connecting the brace 7 and the corner portion of the steel frame 34, and the distance between the fulcrums is reduced to prevent buckling.

[0005] The installation work of such a steel frame assembly 35 is as follows.
This is done as follows. The existing window, waist wall and upper leaning wall are removed, and then the concrete anchor 9 is driven into the inner periphery of the opening 31 as shown in FIG. The steel frame assembly 35 shown in FIG. 7B faces the opening so that the protruding portions of the stud 8 and the anchor 9 enter each other, and the periphery of the opening and the steel frame assembly 35
Fill the mortar between.

[0008] That is, in the portion of the hanging wall taken along the line AA in FIG. 9 (a), as shown in FIG. Horizontal material 33
Are fixed with bolts 39, and the formwork 38 is fixed with width fixing bolts 40 functioning as spacers. When the mortar is filled in the space below the flange portion of the H-section steel from the injection port 38a provided on one side of the mold, the horizontal member 33 is integrated with the hanging wall 37.

On the other hand, as shown in FIG. 8 (b), in the portion of the pillar 3 as viewed from the direction of the arrows BB in FIG. Abut
After stopping the width in the same manner, the mortar is poured from the upper opening as indicated by an arrow 39 in FIG. In any part, the stud 8 on the steel frame assembly side and the anchor 9 on the building side are covered with mortar, and when they are solidified, the steel frame assembly 35 is integrated with the building. Then the waist wall 40
9 and (a) of FIG.
The reinforcement is completed as shown in FIG. 9, and the horizontal cross section is as shown in FIG. FIG. 9A is an elevation view as viewed from the indoor side after the reinforcement work, and FIG. 10 is an external view from the lower floor to the upper floor after the work is performed for each floor.

[0008]

By the way, in the reinforcing structure completed in this way, the V-shaped braces 7, 7 do not have a considerably large cross section, even though the support members 36 are provided. Succumb. For example, H-shaped steel of about 200 × 200 mm is often used for reinforcing a school building, for example, because if it buckles, it will not function as a seismic reinforcement. However, if the cross section of the V-shaped brace is too large compared to the columns or beams of reinforced concrete, another problem occurs in that the body structure is unreasonable due to the force concentrated on the reinforcing portion, and the balance with buckling prevention becomes difficult. Often.

On the other hand, at the end of the V-shaped brace, a considerably large gusset plate 26 is attached as shown in FIG. As can be seen from FIG. 9A, the V-shaped brace 7 having a large cross section and the plate 26 reduce the effective area of the window 42. Further, in order to insert the steel frame assembly 35 into the opening 31, the width of the entire window is not particularly reinforced by the vertical members 32 and the horizontal members 33, as shown in FIG. The window design is considerably cramped, and the sense of openness in the room is greatly reduced. Furthermore, since the V-shaped braces 7, 7 protrude from the inner surface of the window, they hinder the operation of opening / closing the window, locking the window, and the like, leaving a problem in usability.

On the other hand, in the construction, the concrete anchor 9 is driven upward at the inner periphery of the opening 31 shown in FIG. The work of filling the mortar has a drawback that it requires skill and labor. Of course, in order to finish as shown in FIG. 9A, a waist wall and a back wall are formed after the steel frame assembly 35 is installed, and window construction is performed. Therefore, long-term construction is required.

[0011] For example, in the case of a school building, a summer vacation in which a construction period is easily secured is used. In addition, since the work is performed for each window and each classroom, the amount of construction is large, and a large number of people must be invested. Therefore, if there are many school buildings that need to be reinforced, the construction will be concentrated in the summer, and the digestion efficiency of the construction will be extremely poor, and if there are many urgent reinforcement works, labor shortages will occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide an opening which does not impair the feeling of opening of an opening in a window of a building and which does not hinder opening / closing operation of the window. Reinforced construction of existing reinforced concrete buildings, which enables simplification and shortening of construction work, and enables the building to have a beautiful appearance even when reinforced. It is to provide a construction method.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a reinforced concrete building having an opening, such as a window, and a V near the opening.
It is applied to the seismic retrofitting method that can attach a character brace and reinforce the building. The feature is that, with reference to FIG. 1 and FIG. 2, the H-section steel is applied to the outer surface of the building in units of a pair of left and right columns 3 adjacent to the building 1 to be reinforced. The ladder-like steel frame structure 2 is built up by extending upward along the pillars and horizontally spanning each floor, and the structural members are braced in a V-shape in the frame of each floor of the steel frame structure. 7
In addition, a number of studs 8 extending in a direction perpendicular to the steel frame structure 2 are welded to the web portions 4a, 6a (see FIG. 2) of the respective H-section steels forming the vertical steel frame 4 and the horizontal steel frame 6. . On the surface of the building, a large number of anchors 9 projecting outward are driven into the steel framed structure 2 at positions corresponding to the vertical steel frames 4 and the horizontal steel frames 6, and the protruding portions of the studs 8 and the anchors 9 are projected. The steel frame structure 2 is connected to the vertical steel frame 4 and the horizontal steel frame 6 so that the portions are intertwined with each other.
Are arranged on the outer surface of the building so as to coincide with the columns 3 and the beams 5 of the building. Then, the space between the H-section steel and the columns 3 and the beams 5 is filled with cement mortar.

While positioning anchors 10 are driven between a number of anchors 9 driven into the building,
A screw is engraved on the tip of the positioning anchor. On the other hand, if the stopping holes 4h and 6h through which the positioning anchors 10 are inserted are provided in the H-shaped steel web portions 4a and 6a of the steel frame structure 2, the steel frame structure 2 is arranged on the outer surface of the building 1. At this time, the positioning anchor 10 is fixed to the stop holes 4h and 6h.
h, and the nut 12 is screwed and fixed so that the steel frame structure 2 can be positioned at the time of construction.

The structural member used as the brace 7 is preferably a double steel pipe-shaped structural member 23,
The structure is such that an inner cylindrical tube 22 to which an axial force is introduced by attaching a joining device 25 which enables connection with the steel frame structure 2 is attached.
And a thin outer tube 21 covering the entire inner tube. The inner tube 22 has an outer tube 21 near the end on one side.
The remaining portion connected to the thick tube and extending to the other side by butt welding or the like is formed by a thin tube 22b having an outer diameter smaller than that of the thick tube. The outer tube 21 is the inner tube 2 on the thin tube side.
2 is weld-stopped.

[0016]

According to the present invention, a steel frame structure in which ladders are assembled and V-shaped braces are incorporated is manufactured in advance so that the vertical and horizontal steel frames match the columns and beams of the building. In the building, the cement mortar is filled between the steel frame structure and the building, so that the lower floor to the upper floor of the building can be reinforced at once, Simplification and a significantly shortened construction period are realized.

Since the V-shaped brace is located outside the room, the size of the opening such as a window is secured as before, and the unpleasant V-shaped brace does not become indoors and the feeling of opening through the window or the like is reduced by the conventional reinforcing method. Larger than that. of course,
The opening and closing and locking of the window are easy as before without being disturbed by the V-shaped brace, and the inconvenience of operation is eliminated. V
Although there are letter-shaped braces, ladder-shaped steel frame structures will be arranged outside the building, so that it can be transformed into an aesthetically pleasing appearance such as accenting a monotonous school building become.

When the positioning anchor is driven into the building, when the steel frame structure is placed on the outer surface of the building, the positioning anchor is inserted into the web portion of the H-section steel to form the steel frame structure. Temporary fixing and positioning are performed,
It can promote smooth and accurate construction.

If a double steel pipe-shaped structural member is used for the V-shaped brace of the steel frame structure, a structure that does not elastically buckle can be provided regardless of the cross-sectional size. In addition, a narrow brace can be adopted, and the feeling of closing the opening such as a window by the brace is reduced. The brace made of double-walled tubular structural material enhances industrial design by its shape and the mounting structure of pin-joined ends, and if it is a monotonous building, it can accentuate or give a light feeling. it can.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The seismic retrofitting method for an existing reinforced concrete building according to the present invention will be described below in detail with reference to the drawings showing an embodiment thereof. FIG. 3 shows a case in which a V-shaped brace is attached to an opening of a window or the like of an existing reinforced concrete building 1 and an outer surface in the vicinity of the opening to apply the seismic reinforcement method to the building. It is a completed appearance view of a building such as a school building.

In this, a ladder-like structure is assembled along the outer surface of the building 1 to be reinforced, and a V-shaped brace is incorporated in the frame for each floor, and a steel frame as shown in FIG. Many structures 2 are used. FIG. 2B is a side view thereof. FIG. 1 is an enlarged view of one floor portion of the steel framed structure 2 of FIG. 4, and H-shaped steels correspond to each floor so as to correspond to the intervals between the adjacent columns 3 and 3 of the building to be reinforced. It is assembled in a ladder shape. The vertical steel frame 4 along the column 3 extends from the lower floor to the upper floor, and horizontal steel frames 6 are passed to the vertical steel frames 4, 4 at positions corresponding to the girders 5 provided at the boundaries of each floor.

In such a steel frame structure 2, a steel structural member is incorporated as each member 7 of the V-shaped brace. The structural member may be in the form of a beam. However, as shown in FIG. 1, a steel tube-shaped structural member is convenient. It can be kept as a brace that does not yield.

In such a steel frame structure 2, web portions 4a, 6a of H-shaped steels forming the vertical steel frame 4 and the horizontal steel frame 6 are provided.
Then, as shown in FIG. 2, a large number of studs 8 extending in a direction perpendicular to the steel frame structure 2 are welded. The above manufacturing process can be performed in a factory where accurate processing can be performed, or a main part can be manufactured in a factory, and can be easily assembled in multiple stages at a construction site.

On the other hand, on the surface of the building to be reinforced,
As shown in FIG. 2, a large number of anchors 9 projecting outward are driven into the steel frame structure 2 at positions corresponding to the vertical steel frames 4 and the horizontal steel frames 6. In addition, a positioning anchor 10 having a long leg is driven between a large number of the driven anchors 9, 9, and a screw is carved at the tip thereof. If the stop holes 4h and 6h through which the anchor 10 is inserted are provided in 6a, the positioning can be easily performed when the steel frame structure 2 is erected, which is convenient.

When such preparation is completed, first, the studs are inserted into the space between the vertical steel frame 4 and the horizontal steel frame 6 of the steel frame structure 2 laid on the ground on the side facing the building with the spiral streaks 11 (see FIG. 2). Entangled in 8. Next, the steel frame structure 2
Is lifted up by a crane, and the vertical steel frame 4 and the horizontal steel frame 6 are aligned with the columns 3 and the beams 5 of the building, and the facing distance L between the beams (see FIG. 2) is, for example, 50 mm.
To the outside of the building to the extent that As a result, the respective protruding portions of the stud 8 and the anchor 9 come into engagement with each other. At this time, the positioning anchor 10 is connected to the H-shaped steel web portions 4a, 6a by the stop holes 4h,
6h, and when the mounting position of the steel frame structure 2 to the building is determined, the nut 12 is hung and fixed.
When the temporary fixing is performed, the mounting state is as shown in FIG. 5, and then the crane is retracted.

Each of the plates 13 of the formwork extending to the column 3 so as to cover the flange portion of the vertical steel frame 4 is attached as shown in FIG. 5 in the manner described with reference to FIG. . On the other hand, from the lower flange portion 6b of each horizontal steel frame 6, a leak prevention plate 14 that covers the facing distance L toward the wall surface is provided as shown in FIGS.

Finally, a mortar is filled between each H-beam and the column 3 and the girder 5. The space between the vertical steel frame 4 and the column 3 may be dropped from the opening of the portion located on the top floor as shown by a downward arrow 15 (see FIG. 5). Between the horizontal steel frame 6 and the beam 5, a gap for concrete casting is secured on each floor as the gap of the facing distance L described above, so that each floor has a downward arrow 16 (see FIG. 5). It is poured. When the mortar is solidified, the spiral streaks 11 reinforce the concrete, and the studs 8 and the anchors 9 cooperate to firmly connect the steel frame structure 2 to the building 1.

FIG. 6 (a) shows the completed reinforcing structure after removing the formwork from the room, and FIG. 4 (a) shows the completed reinforcing structure from the outside. FIG.
In this case, the width of the window 17 is larger than the width of the window 42 in the column interval. That is, since the H-shaped steel of the vertical steel frame 4 of the steel frame structure 2 is narrower than the width of the column 3, the vertical steel frame 4 does not cover the left and right portions of the opening of the window, and the window is not widened. You can keep it as it is.

Regardless of whether the above-mentioned anchor 9 is attached to the building or the steel frame structure 2 is integrated, the work is performed from outside the building, and the windows and walls must be modified as they are. There is no. In other words, there is no need to remove or restore windows and walls, and the mortar filling operation can be performed all downwards, etc., so that the construction period can be significantly reduced, and thus the construction cost can be significantly reduced. .

Since the construction is mainly performed on the outer surface, lessons and office work will not be disturbed except for a little noise even if there is a person in the room. Since the construction period is short, construction can be partially performed sequentially on weekends and weekends, and it is possible to proceed in parallel with reinforcement work for other buildings. The conventional construction method could not reinforce the school building except during summer vacation, but it can be distributed throughout the year.

As shown in FIG. 3, the steel frame structure 2 is applied to, for example, the first half or the second half of a classroom, and a flat and monotonous appearance of the school building is accentuated, and the aesthetically superior structure is obtained. If a decorative member 18 having an arch shape or a mountain shape is attached to the top as shown in the figure, a modern feeling is exhibited, and the design is further improved.

Incidentally, the structural member constituting the V-shaped brace 7 incorporated in the steel frame structure 2 is a single tube or a bending resistance tube inserted as proposed in Japanese Patent Application Laid-Open No. 4-149345. As shown in FIG. 1, a clevis device 19 is employed in order to make the supporting points and joints of the double steel pipe with improved buckling strength and an ideal pin support structure in terms of structural mechanics.

As the clevis device, if a clevis joint having a waterproof function described in Japanese Patent Application Laid-Open No. Hei 10-317506 proposed by the present applicant is adopted, an ideal pin support function in terms of structural mechanics over a long period of time is obtained. You will be able to demonstrate. The appearance of such a clevis joint is light in design and the discomfort due to the presence of the brace 7 is further reduced.

Here, an example of a double steel pipe-shaped structural material suitable for using the above-described double steel pipe as a brace will be described. FIG. 6B shows a double steel pipe 23 in which the inner pipe 22 is inserted into the outer pipe 21, and is designed to be particularly suitable as a brace located outdoors. .

The inner tube 22 is a main structural member which receives an axial force, and end members 24 _A and 24 _B are fixedly integrated at both ends. And the joining device 25 which enables connection with a steel frame structure is attached to this end member. This joining device is a clevis eye 25M, for example.
Gusset plate 2 attached to the steel frame structure side
6 (see FIG. 1). In addition,
The clevis eyes 25M _A and 25M _B are end members 24.
_A and 24B are screwed and attached to short screw holes 27 extending in the axial direction provided in _B.

The double steel tube-shaped structural member 23 is composed of an inner tube 22 and an outer tube 21. The inner tube is located near one end, that is, A at the end located on the left side in FIG. 6B. Only the portion is a thick tube 22a, and the remaining portion on the other side connected to the thick tube is formed to be thin. The thick-walled tube 22a is, for example, about twice as long as the diameter of the inner cylindrical tube 22, and most of the remaining portion is a long thin-walled tube 22b.

The thin-walled tube 22b and the thick-walled tube 22a are joined by butt welding or the like to form one inner cylindrical tube 22, but the outer diameter of the thick-walled tube 22a is larger than that of the thin-walled tube 22b. ing. That is, in the illustrated example, a step 22m is formed on the outer surface of the joining portion.

The outer tube 21 is a thin tube that covers the entire inner tube 22 with a slight gap t between the outer tube 21 and the outer surface of the thick tube 22a. That is, since the outer tube 21 is a stiffening tube as a bending resistance steel tube for suppressing the bending of the inner tube 22, it covers most of the thick tube 22a as well as the thin tube 22b. End member 24 _A from the end member 24 _B in the example of FIG.
And covers all of the thick tube 22a.

The end members 24 _A and 24 _B at each end are butt-welded to the ends of the thick pipe 22 a and the thin pipe 22 b to be integrated, and the above-mentioned screw hole 27 is formed therein. The outer cylinder tube 21 is welded stop around 24a of the end member 24 _B of the B side located on the thin pipe side, extending toward the other end member 24 _A from its outer periphery, at the thick walled tube 22a is It is not fixed. Therefore, Kurebisuai 25M _A, through 25M _B end member 24 _A, 24 axial forces introduced into _B is not to be transmitted to the outer cylinder tube 21, it is always placed in a no-load free state.

The thick-walled pipe 22a is made of a double steel pipe-shaped structural material 2
Since the total length of 3 is at most several tens of centimeters even if it is 3 meters, it is easy to machine the outer diameter to be very close to the inner diameter of the outer tube 21. Since the thin tube 22b is smaller than the diameter of the thick tube 22a as described above, the inner tube 22 can be easily inserted into the outer tube 21 from the thin tube side even if it is long.

The above-mentioned clevis eyes 25M _A and 25M _B
Is adopted, only the ideal axial force is introduced from the steel frame structure into the inner tube 22, and unnecessary bending of the inner tube is generated. Can be avoided.

According to the double steel pipe-shaped structural member having such a configuration, when a large axial compressive force acts on the inner cylindrical tube 22 as the main structural member via the joining device 25 such as the clevis eye 25M, the inner cylindrical tube 22 is not subjected to any The tubular tube 22 elastically buckles at the portion of the thin-walled tube 22b and tends to bend. However, the outer tube 21 is not the thick tube 22a.
, So that the thick-walled tube 22a is restricted by the outer tube even if it tries to bend. The bending resistance is sufficiently exerted even when the outer tube 21 is thin, and the weight of the double steel tube-shaped structural member 23 can be reduced even by the presence of the outer tube.

In the inner tube 22 whose bending is suppressed by the outer tube 21, plastic deformation occurs in the thin tube 22b when a larger axial force acts. At that time, since the thick-walled tube 22a has not yet undergone plastic deformation, the thin-walled tube 22b integrated with the thick-walled tube 22a is maintained in the straightness of the axis line under the influence of the high rigidity of the thick-walled tube 22a. It will be easier. For this reason, in the thin-walled tube 22b, it is easy to generate uniform axial plastic deformation in the axial direction. Even if the waves due to the deformation attempt to spread outward, they are blocked on the inner surface of the outer tube 21, and the generation of a non-uniform waveform that locally hits a large wave is suppressed.

As shown in FIG. 6 (b), a double steel pipe-shaped structural member 2
In 3, the outer cylinder tube 21 when the inner cylinder tube 22 contracts succumbed plastic seat beyond the end member 24 _A Kurebisuai 25M _A
However, the amount of buckling deformation during that time is determined by a double structure (not shown) having a structure opposite to that of the present example in which the outer tube is the main structural material and the inner tube acts as a stiffening tube. It is remarkably suppressed as compared with the steel pipe type structural material.

Therefore, even when a large force such as an earthquake is applied, the deformation of the steel frame structure at the stage where the main structural member is plastically deformed can be suppressed relatively small. That is, the effect that the proof stress of the inner cylindrical tube 22 is substantially increased is exhibited. As a result, it is possible to secure enough time to escape before the structure collapses, and a person who notices the deformation may take an evacuation action while the double steel tubular structural member 23 is stepping on with a large proof stress. it can.

Although such a double steel pipe-shaped structural member 23 can be used for the beam member shown in FIG. 1, it is suitable when used for the brace 7 interposed in the steel frame structure. . That is, as the end member 24 _B on the side that secure the outer tube pipe 21 by welding becomes above, in the example of FIG. 1 are attached such that the upper inclined ends labeled B section In this case, rainwater does not enter the outer tube 21 from the portion B. In the lower part A, a gap t exists between the thick pipe 22a and the outer pipe 21 so that the pipe is open. However, it goes without saying that there is no intrusion of rainwater.

Therefore, it is not necessary to perform rust prevention treatment on the facing portion of the outer tube 21 and the inner tube 22 or even if such treatment is performed, the quality of the treatment is not improved. In addition, the outer tube 2
Since the welding of the first end member 24 _B is made at the end portion of the outer cylinder tube, a very simple task compared to when welding in an intermediate portion, that maintained and fixed free state of the outer cylinder tube 21 Can be. In general, the number of steps for manufacturing the double-walled steel pipe-shaped structural member 23 can be reduced and the operation can be simplified, so that the manufacturing cost can be reduced.

By the way, the end member 24 _{A in the} portion _A
Screw holes 27 is, for example, right-hand thread mutually biting into the screw 25 m _A provided on the base of Kurebisuai 25M _A, the screw 25 m _B provided in Kurebisuai 25M _B screwed to the end member 24 _B of the B portion of the reverse helical By using a left-handed screw, the work of adjusting the distance between the pin holes for connecting and supporting the clevis eyes 25M _A and 25M _B can be realized by a turnbuckle-type operation simply by rotating the double steel pipe-shaped structural member 23, and the assembling work is smooth. Is achieved. Further, depending on the screwing amount, a pretension can be applied to the inner tube.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a part of a steel frame structure for realizing a seismic retrofitting method for an existing reinforced concrete building according to the present invention, and showing one floor of the structure in FIG. 4;

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a completed appearance view of a building such as a school building in which an existing reinforced concrete building is applied with a seismic retrofitting method.

FIG. 4A is a front view in which one of the steel frame structures is integrated on the entire surface of a building, and FIG. 4B is a side view thereof.

FIG. 5 is a perspective view showing the part of FIG. 2 in a three-dimensional manner.

FIG. 6A is an external view of a building viewed from the indoor side around a window after seismic reinforcement work, and FIG. 6B is a vertical cross-sectional view of a double steel pipe type structural material suitable for use as a brace.

FIG. 7 (a) is an elevational view of a building having a large opening for construction according to the prior art as viewed from the indoor side, and FIG. 7 (b).
Is an elevation view of a steel frame assembly attached to the opening.

8A is an enlarged sectional view taken along line AA in FIG. 9A, and FIG. 8B is an enlarged sectional view taken along line BB in FIG. 9A.

9 (a) is an elevational view from the indoor side near a window reinforced by seismic resistance according to the related art, and FIG. 9 (b) is a view of C- in FIG. 9 (a).
FIG.

FIG. 10 is an external view of a school building to which a conventional construction method is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Building, 2 ... Steel frame structure, 3 ... Column, 4 ... Vertical steel frame, 4a ... Web part, 4h ... Stop hole, 5 ... Beam, 6 ... Horizontal steel frame, 6 ... Web part, 6h ... Stop hole, 7 ... Brace, 8 ...
Stud, 9 ... anchor, 10 ... anchor for positioning,
12 ... nut.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E04G 23/02

Claims (3)

(57) [Claims] 1. A V-shaped brace is attached to an opening of a window or the like of an existing reinforced concrete building and the vicinity thereof,
In the seismic retrofitting method capable of seismic retrofitting of the building, an H-section steel is applied along the pair of columns so that the building can be applied to the outer surface of the building in units of a pair of right and left columns adjacent to the building to be reinforced. The ladder-like steel frame structure is built up by extending upward and extending horizontally corresponding to each floor, and the structural members are assembled as braces in a V-shape within the frame of each floor of the steel frame structure. A large number of studs extending in a direction perpendicular to the steel frame structure are welded to the web portion of each of the H-shaped steels forming the vertical steel frame and the horizontal steel frame, and project outward to the surface of the building. A large number of anchors are driven into the steel frame structure at positions corresponding to the vertical steel frames and horizontal steel frames, and the steel frame structure is so formed that the protruding portions of the studs and the anchors interlock with each other. The vertical steel frame and the horizontal steel frame are arranged on the outer surface of the building so as to coincide with the columns and beams of the building, and the cement mortar is filled between each of the H-sections and the columns and beams. A seismic retrofitting method for existing reinforced concrete buildings. 2. A positioning anchor is driven between a number of anchors driven into the building,
A screw is engraved at the tip of the positioning anchor, and a stop hole through which the positioning anchor is inserted is provided in a web portion of the H-shaped steel of the steel frame structure, and the steel frame structure is used for building. 2. The arrangement according to claim 1, wherein, when the steel frame structure is placed on an outer surface, the positioning anchor is inserted into the stop hole and a nut is screwed and fixed so that the steel frame structure can be positioned when being built. The seismic retrofitting method for the existing reinforced concrete building described. 3. The structural member used for the brace is a double steel tubular structure, and the double steel tubular structure is provided with a joining device that enables connection with the steel frame structure. An inner cylinder tube to which an axial force is introduced, and a thin outer cylinder tube that covers the entire inner cylinder tube, wherein the inner cylinder tube has a small gap near the one end on one side thereof. The thick tube is separated from the thin tube, and the remaining portion connected to the thick tube and extending to the other side by butt welding or the like is formed of a thin tube having an outer diameter smaller than that of the thick tube. The seismic retrofitting method for an existing reinforced concrete building according to claim 1, wherein the inner tube is welded to the inner tube.