JPH06101292A - Reinforced concrete wall having built-in unbonded flat-steel brace - Google Patents

Abstract

PURPOSE:To obtain a reinforced-concrete earthquake resisting wall resisting compression and bending by integrally burying box-shaped reinforcing hardware with a slit, into which flat steel is penetrated, into the wall together with an anchor reinforcement at the mounting end section of a flat steel brace disposed in a V shape. CONSTITUTION:Box-shaped reinforcing hardware 4 at an interval or having a slit S, where flat steel braces 2 are penetrated, is installed integrally together with anchor reinforcements 7 at the mounting end sections of the flat steel braces 2 disposed into a reinforced concrete wall 1 in a V shape. Resisting force against rupture in bearing pressure and rupture in bending in the joints of the braces 2 is increased, and earthquake resisting force is augmented without enlarging wall thickness. Accordingly, a reinforced-concrete earthquake resisting wall having large strength can be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced concrete wall containing unbonded flat steel braces (hereinafter referred to as flat steel brace RC wall) which is used as an earthquake-resistant wall for medium and low-rise buildings.
Regarding

[0002]

2. Description of the Related Art In recent years, reinforced concrete walls containing unbonded flat steel braces have been widely used as earthquake-resistant walls for medium and low-rise buildings. The structure of the flat steel brace RC wall is shown in FIG. 7A,
As illustrated in B, a flat steel brace 2 in which adhesion to concrete is prevented by an unbonding agent is arranged in a substantially rectangular V-shaped RC wall 1 and is installed in a substantially V shape. The end condition is that the flat steel brace 2 is fixed and the RC wall 1 is free. Therefore, the flat steel brace 2 bears the seismic force entering the flat steel brace RC wall as an axial force, and the RC wall plate 1 is a buckling stiffener for the flat steel brace 2. If the RC wall plate 1 satisfies the strength condition and the rigidity condition, the buckling of the synthetic brace structure as a whole does not occur.

[0003]

With respect to the flat steel brace RC wall, many examples of destruction of the end portions designated as a and b in FIG. 7 have been reported. FIG. 7A shows an example in which the flat steel brace lower end portion “a” is locally broken against the deformation exceeding the limit. FIG. 7B shows an example in which the RC wall upper end b on the tensile brace side is damaged due to contact with the flat steel brace 2 during deformation, and buckling fracture occurs at that part when a load is applied in the opposite direction (during compression) and the yield strength is reduced. Is shown. Therefore, various methods of reinforcing the end have been devised so far, but the conditions for stiffening the end have not been clarified yet. In order to improve the proof stress and deformation performance of the flat steel brace RC wall, proper end reinforcement is necessary. The failure mechanism of the flat steel brace RC wall is roughly classified into bearing failure or bending failure. That is, when an axial force acts on the flat steel brace and an out-of-plane deformation occurs in the RC wall, a couple of resistance is necessary to restrain the rotation of the end of the RC wall. The breakage of the flat steel brace RC wall end is a punching shear breakage due to the stiffening force forming the couple. Therefore, it is necessary to analytically grasp the magnitude of the end stiffening force and develop a method for reinforcing the end part against this stiffening force. As described above, a large stiffening force is generated at the end of the flat steel brace RC wall. This large stiffening force acts to push the RC wall out from the inside, and the RC wall breaks, causing local buckling at the end of the flat steel brace. In other words, the end fracture of the RC wall is R due to the bearing pressure of the flat steel brace.
Punching shear failure of the C wall. FIG. 8A illustrates such a destruction mechanism. It was confirmed by an experiment that the bearing area for the RC wall of the flat steel brace is the triangular region c at the end of the flat steel brace as shown in FIG. 8B. FIG. 9 shows a collapse mechanism of the anchor muscle 3.

[0004]

As a means for solving the above-mentioned problems of the prior art, a reinforced concrete wall with an unbonded flat steel brace built therein according to the present invention is as shown in FIGS. Unbonded flat steel brace 2
In the reinforced concrete wall 1 in which is arranged substantially in the shape of V, an end reinforcing metal member 4 having a structure that allows the flat steel brace 2 to penetrate is integrally formed in the reinforced concrete wall 1 at the position of the end of the flat steel brace 2. It is characterized in that it is buried (Fig. 1).

In the reinforced concrete wall containing the unbonded flat steel brace of the present invention, the end reinforcing metal member has an angle 5 arranged in parallel in the horizontal direction with an interval s enough to penetrate the flat steel brace 2. Angle 5
Of the end braces 6 fixed to both end portions of the and the anchor bars 7 fixed to one end of the angle 5 (FIG. 2), and the end reinforcing metal member is cast from gutile cast iron or the like. It is composed of a rectangular parallelepiped box body 8 having an opened lower surface, a top wall 8a thereof is provided with a slit 9 for penetrating the flat steel brace 2, and one end of an anchor bar 7 is joined to the upper wall 8a (Fig. 3) and
The end reinforcing metal fitting has a configuration in which one end of a reinforcing bar 13 or an anchor bar is joined to a flat steel plate 12 having a slit 10 or a notch 11 through which a flat steel brace is penetrated (FIG. 4), and Each reinforced concrete wall is also precast.

[0006]

[Function] The end reinforcing metal member strongly resists the stiffening force. At that time, in the end reinforcing metal member 4, a stiffening force of several% (about 5%) of the yield axial force of the flat steel brace 2 acts on the end portion of the RC wall 1 evenly distributed over the entire angle 5, and The end reinforcing metal member 4 alone resists the end stiffening force, and thus resists bearing failure and bending failure.

[0007]

EXAMPLE An example of the present invention shown in the drawings will be described below.
FIG. 1 shows a precast reinforced concrete wall 1 in which unbonded flat steel braces 2 are arranged in a substantially V shape and built in, and end reinforcing metal members 4 are provided at upper and lower end positions of the flat steel braces 2 in the reinforced concrete wall 1. 2 shows an embodiment of a flat steel brace RC wall integrally embedded in the.

FIGS. 2A to 2C show a typical embodiment of the end reinforcing metal member 4, which has two angles 5 and 5 in the horizontal direction with a space s enough to penetrate the flat steel brace 2.
Are arranged in parallel with each other, and end plates 6 are commonly fixed to both ends of the two angles 5 and 5, and are formed in a box shape with one surface opened. One ends of several anchor bars 7 are fixed to the angle 5 by a welding method in such a manner as to project vertically to the box-shaped opening surface side.
As shown in the usage pattern in FIG. 1, the end reinforcing metal piece 4 is provided at the upper end portion and the lower end portion of the flat steel brace 2,
The angles 5 are arranged parallel to each other along the long side of the RC wall 1, and the anchor ribs 7 are embedded in a direction perpendicular to the inside of the RC wall 1. The flat steel brace 2 is arranged so as to penetrate a portion of the two angles 5 and 5 with a spacing s.

3A and 3B show an example of an end reinforcing metal member cast from ductile cast iron. This is composed of a rectangular parallelepiped box whose bottom surface (however, the distinction between top and bottom is not used in particular) is opened, and a slit 9 having a width and a length which allows the flat steel brace 2 to penetrate therethrough is provided on its top wall 8a. Has been. Further, a plurality of screw holes 15 for screw-joining the anchor muscles 7 to the upper surface wall 8a are provided in a two-row arrangement, and all or a part of the screw holes 15 are screwed to the upper end. Anchor muscle 7 forming 7a is screwed and integrally joined. The mode of use and the effect of this end reinforcing metal piece are almost the same as those in FIG.

FIGS. 4A and 4B show a further different embodiment of the end reinforcing metal member, which is a plate (fork-shaped iron plate) 12 having a slit-like notch 11 of a width and a length which allows the flat steel brace 2 to penetrate therethrough. 10 to 13mm in diameter at both ends of
The reinforcing bars 13 having an effective length of about 300 mm are arranged at right angles, and one end of the reinforcing bars 13 is integrally joined to the plate 12. The plate 12 has a thickness of 16 mm, a width of 90 mm, and a length of about 500 to 600 mm. The usage mode of this end reinforcing metal piece is as illustrated in FIG. 4B, and the flat steel brace 2 is arranged so as to penetrate the notch 11 of the plate 12.

5A and 5B, the end reinforcing metal member is provided with a slit 10 having a width and a length which allows the flat steel brace 2 to penetrate therethrough in the central portion of the plate 12, and through holes 16 at both ends.
Is provided and a reinforcing bar 13 having a predetermined length is passed in parallel therewith. The mode of use of this end reinforcing metal article is as illustrated in FIG. 5B, and the plate 12 is the flat steel brace 2
And the reinforcing bars 13 are arranged parallel to the flat steel brace 2.

The edge reinforcing metal member shown in FIG.
Is used at the lower end where the two flat steel braces 2, 2 intersect, and the plate 12 has a width that allows the parallel brace 2 to penetrate therethrough from both ends in a symmetrical arrangement. A slit-shaped notch 11 having a length is provided. Further, one end of a reinforcing bar 13 arranged in the longitudinal direction parallel to the plate surface is integrally joined to both ends of the plate 12 by means such as welding. As can be estimated from the metal piece arranged at the lower end portion of FIG. 1, the usage mode of the edge reinforcing metal piece is such that the plate 12 and the reinforcing bar 13 have the RC wall 1
The two flat steel braces 2, 2 are arranged parallel to the long side of
The intersecting points of are penetrated by the notches 11 at both ends of the plate 12.

As a method of reinforcing the RC wall end, the above-mentioned method using the end reinforcing metal piece and the method of mixing steel fiber or the like into the concrete to increase the punching shearing force of the concrete itself are used together. That is also effective. .

[0014]

EFFECTS OF THE INVENTION The reinforced concrete wall with an unbonded flat steel brace built-in according to the present invention achieves a simple and sufficiently safe end reinforcement by means of an end-reinforcing metal piece, and even if the flat-steel brace has a large yield strength, RC An economical flat steel brace RC wall can be manufactured without increasing the wall thickness of the wall.

[Brief description of drawings]

FIG. 1 is a front view showing a flat steel brace RC wall of the present invention.

2A, 2B, and 2C are a plan view, a front view, and a cross-sectional view of a use state of an end reinforcing metal piece.

3A and 3B are a perspective view of different end reinforcing metal pieces and a cross-sectional view of a usage state.

4A and 4B are a perspective view and a front view of a usage state of a different end reinforcing metal piece.

5A and 5B are a perspective view and a front view of a usage state of a different end reinforcing metal piece.

FIG. 6 is a perspective view of a different end reinforcing metal piece.

7A and 7B are front views showing a damaged portion of a conventional flat steel brace RC wall.

FIG. 8A is a side view showing an RC wall end damage mechanism, and FIG.
FIG. 4 is a front view showing a bearing area of a brace.

FIG. 9 is a cross-sectional view showing a mechanism of collapse of anchor muscles.

[Explanation of symbols]

 1 RC Wall 2 Flat Steel Brace 4 End Reinforcing Hardware s Interval 5 Angle 6 End Plate 7 Anchor Bar 9 Slit 10 Slit 11 Notch 12 Plate 13 Reinforcing Bar

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Higashibata 2-5-14 Minamisuna, Koto-ku, Tokyo Incorporated Takenaka Corporation Technical Research Institute (72) Inventor Ichiro Inoue 27A-401 Shinashi Rooftop Suita City, Osaka Prefecture

Claims (5)

[Claims] 1. In a reinforced concrete wall in which unbonded flat steel braces are arranged in a substantially V-shape and incorporated therein, at the end of the flat steel brace, an end-reinforcing metal member having a structure capable of penetrating the flat steel brace is reinforced concrete. Reinforced concrete wall with unbonded flat steel braces, characterized by being integrally embedded in the wall. 2. An end reinforcing metal member is an angle arranged parallel to a horizontal direction with an interval enough to penetrate a flat steel brace, end plates fixed to both ends of the angle, and the angle. An reinforced concrete wall with an unbonded flat steel brace built therein according to claim 1, characterized in that it comprises an anchor bar fixed at one end thereof. 3. The end-reinforcing metal member comprises a box-shaped box body, which is cast from gutile cast iron or the like and has an opened lower surface.
The reinforced concrete with a built-in unbonded flat steel brace according to claim 1, characterized in that the upper wall is provided with a slit for penetrating the flat steel brace, and one end of an anchor bar is joined to the upper wall. wall. 4. The end reinforcing metal member is characterized in that one end of a reinforcing bar or an anchor bar is joined to a flat steel plate having a slit or notch through which a flat steel brace is penetrated. Item 1. A reinforced concrete wall containing an unbonded flat steel brace described in item 1. 5. The reinforced concrete wall with unbonded flat steel braces according to claim 1, wherein the reinforced concrete wall is precast.