JPH0156234B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a reinforced concrete shear wall (hereinafter referred to as an RC shear wall) used in the construction of medium- and low-rise buildings, and more specifically, it relates to a reinforced concrete shear wall (hereinafter referred to as an RC shear wall) that has a sufficiently large Moreover, it relates to RC shear walls with excellent deformation performance.

Conventional technology Conventional shear failure type shear walls have a structure in which concrete is simply reinforced with wall reinforcing bars (vertical and horizontal bars). Therefore, as shown by curve A in FIG. 1, its load deformation performance is large, but deformation is small at the maximum proof stress, and after the maximum proof stress, the proof stress decreases rapidly. That is, it exhibits brittle fracture properties and has low deformation performance (capacity).

On the other hand, bending yield type shear walls are also known that have a configuration in which stud reinforcement is provided within the wall plate. Although this bending-down type shear wall has improved deformation performance compared to the shear failure type shear wall, it has the disadvantage that it is difficult to form a column mechanism by stud reinforcement arrangement.

Also known is a slit-type shear wall in which slits are formed in the vertical direction of the wall plate. This slit-type shear wall also has somewhat improved deformation performance, but the larger drawbacks are that the strength is reduced and the slits impair the appearance and design of the wall panels. Japanese Unexamined Patent Publication 1983-
The rigidity-adjustable shear wall described in Japanese Patent No. 168762, which is constructed of wall plates that are divided into a plurality of vertical joints along vertical joints, has almost the same drawback.

As mentioned above, conventional RC shear walls are
It is extremely difficult to improve deformation performance without reducing maximum yield strength, and this has become an issue to be solved.

Therefore, an object of the present invention is to provide an improved RC shear wall with an improved structure that exhibits excellent deformation performance without causing a sudden drop in strength even after reaching the maximum strength.

Means for Solving the Problems First and Second Inventions As a means for solving the problems of the prior art described above, a reinforced concrete shear wall according to the first invention has a preferred embodiment shown in FIG. As shown, in a reinforced concrete shear wall where a reinforced concrete wall board is integrally provided within the trench plane surrounded by reinforced concrete columns and beams, both ends are installed as vertical reinforcing bars perpendicular to the wall board 3. Large-diameter reinforcing bars 4 firmly anchored to the beams 2 and 2' are placed,
The wall plate 3 is characterized by providing easy-to-shear areas with a small shearing force transmission capacity in portions along the columns 1, 1' and the beams 2, 2'.

The second invention is a reinforced concrete shear wall in which a reinforced concrete wall plate is integrally provided within a trench plane surrounded by reinforced concrete columns and beams, and the wall plate 3 is reinforced in a vertical direction. Large-diameter reinforcing bars 4 with both ends firmly fixed to the beams 2 and 2' are arranged as reinforcing bars.
The wall plate 3 is provided with easy shear points with a small shearing force transmission capacity in the parts along the columns 1, 1' and the beams 2, 2', and also in the part along the large diameter reinforcing bars 4, which has a shearing force transmission capacity. It is characterized by the provision of easy-to-shear areas with small shearing properties.

Function: While the wall plate 3 works integrally with the rigid frame structure formed by the columns 1 and beams 2 (in other words, until it is destroyed)
In this case, the secondary rigidity is improved because the large-diameter reinforcing bars 4 act as wall reinforcement (see curves ◯ and ◯ in Fig. 1). However, once the integrity of the rigid frame structure formed by the wall plate 3, columns 1, and beams 2 is destroyed, the strength does not decrease much, and the damage to the wall plate 3 does not increase. The deformation increases as the yield of 4 (curve B in Figure 1). Then, as the deformation increases, large diameter reinforcing bars 4
acts like a stud and prevents a decline in yield strength.

In other words, if the maximum strength is reached and the easily sheared parts are destroyed, the integrity of the rigid frame frame formed by the wall plate 3, columns 1, and beams 2 will be lost, and the damage to the wall plate 3 will continue. stops, the yield strength is maintained as the large-diameter reinforcing bars 4 yield, and the deformation increases as yield elongation.

In particular, as a result of the destruction of the easily sheared areas along the columns 1, 1' and beams 2, 2', and the easily sheared areas along the large-diameter reinforcing bars 4, the wall plate 3 is vertically divided into two or more parts. The wall plate 3 that has been exposed to the wall will undergo rotational deformation due to the horizontal seismic force (Fig. 6). Due to this rotational deformation, the beams 2 and 2' tend to bulge outward, and with the help of the yield elongation of the large-diameter reinforcing bars 4, the dividing wall plate 3 becomes easy to rotate, causing the entire seismic wall to deform significantly. The amount of deformation increases (Figure 6). On the other hand, large diameter reinforcing bar 4
Because the yield strength tightly restrains the bulging deformation of the beams 2, 2', there is no sudden drop in yield strength after the maximum yield strength.

Example Next, illustrated embodiments of the present invention will be described.

In FIGS. 2 and 3, 1 and 1' are left and right pillars, and 2 and 2' are upper and lower beams. Reference numeral 3 denotes a wall plate provided within the frame surface surrounded by the pillars and beams, each of which is integrally formed as a reinforced concrete structure.

The reinforcing bars for columns 1 and 1' and beams 2 and 2' have a thickness of D13.
The structure is such that main reinforcements 1a and 2a of approximately 6 mm in diameter are reinforced by winding the required amount of hoop reinforcements 1b and stirrup 2b of approximately φ6.

The vertical and horizontal reinforcements 3a and 3b of the wall plate 3 are made of reinforcing bars with a diameter of about 4 mm, and are configured as double reinforcements with an interval of 100 mm (Figure 3). The vertical and horizontal reinforcements 3a and 3b are both inserted sufficiently deep into the column reinforcing bars and beam reinforcing bars and anchored therein.

Next, reference numeral 4 in the figure indicates large-diameter reinforcing bars arranged as vertical longitudinal reinforcements in the wall plate 3 described above. For this large-diameter reinforcing bar 4, use a reinforcing bar with a thickness of about D19, and place it at two locations in the center of approximately three equal parts of the horizontal dimension of the wall plate 3.
Two reinforcements are arranged at a parallel interval of 100 mm, and the upper and lower ends 4a and 4b are the main reinforcements 2 of the upper and lower beams 2 and 2'.
a, the stirrup 2b is inserted sufficiently deeply into the assembled reinforcing bar cage, and is bent at a substantially right angle and anchored. However, the left and right 2 located near the center
The large-diameter reinforcing bars 4, 4 are formed as so-called rectangular hoop bars.

In the figure, reference numeral 5 denotes a vinyl chloride pipe that has a cross-sectional defect in the wall plate 3 to form an easily sheared area with a small shearing force transmission capacity. The vinyl chloride pipe 5
The outer diameter of the column is about φ24, and the column 1,
1' and the peripheral area along the beams 2 and 2' (Fig. 2), and is installed at an intermediate position (Fig. 3) between the vertical and horizontal reinforcements 3a and 3b, which are double reinforced on the wall plate 3. . Each vinyl chloride pipe 5 is divided at a position where it intersects each large-diameter reinforcing bar 4.

Therefore, the load deformation performance of the RC shear wall with the above configuration is as shown by the curve ○ and b in Figure 1, where the vinyl chloride pipe 5 is destroyed at point ○, where the yield strength is not higher than necessary ( In other words, the easily sheared parts of the wall board 3 are destroyed), so the proof strength does not increase much after that, and the damage to the wall board 3 does not increase. And R=20
After ×10 ^-3 _rad , the large-diameter reinforcing bars 4 act as studs and prevent a decrease in yield strength.

Second Embodiment Most of the configuration of the RC shear wall shown in Figure 4 is as follows:
Although the structure is common to that of the first embodiment, the feature of the structure of this embodiment is that vinyl chloride which forms an easy-to-shear point in the middle of the large-diameter reinforcing bars 4, 4 arranged in parallel in the vertical direction The pipe 6 is arranged. The vinyl chloride pipe 6 also has an outer diameter of about φ24, and is inserted between the double reinforcements 3a and 3b of the wall board 3. The length of the vinyl chloride pipe 6 is set to be approximately close to the upper and lower beams 2, 2'. In addition,
As in this embodiment, it is preferable to have the large-diameter reinforcing bars 4 and the easily sheared parts coincident with each other in terms of workability and practicality, but it is also possible to implement the construction in a similar manner with a configuration in which both are located at separate positions.

Therefore, in the case of this RC shear wall, when the maximum strength is reached and the PVC pipes 5 and 6 are destroyed (that is, the easily sheared parts of the wall board 3 are destroyed), the wall board 3 becomes larger in diameter. It is vertically divided into three blocks with the position of the reinforcing bar 4 as a boundary, and exhibits rotational deformation as shown in FIG. This rotational deformation is facilitated by the bulging deformation of the beams 2, 2' and the yield elongation of the large-diameter reinforcing bars 4, so that damage to the wall plate 3 is prevented from progressing after reaching the maximum strength, and the entire shear wall is The deformation of increases sufficiently. On the other hand, since the beams 2 and 2' are restrained by the yield strength of the large-diameter reinforcing bars 4, a sudden drop in yield strength after reaching the maximum yield strength is prevented.

Third Embodiment The RC shear wall shown in FIG.
The structure is such that vinyl chloride pipes 5 and 6 are installed in the middle part of the pipe 4 to form an easy shearing area.

Even with such a configuration, the deformation performance under load is close to that of the first and second embodiments.

Effects of the present invention As described above in detail in conjunction with the embodiments, according to the reinforced concrete shear wall according to the present invention, the large-diameter reinforcing bars 4 also work as wall reinforcement, so that double rigidity is improved. . Moreover, the integrity of the rigid frame structure formed by the wall plate 3, columns 1, and beams 2 is lost when the easily sheared parts (PVC pipes 5 and 6) are destroyed, and the progress of damage to the wall plate 3 is stopped. It will be done. Moreover, the deformation of the entire seismic wall increases due to the yield elongation of the large-diameter reinforcing bars 4, the bulging deformation of the beams 2 and 2', and the rotational displacement of the divided wall plates 3, resulting in excellent deformation performance. On the other hand, the large-diameter reinforcing bar 4 has a yield strength of the beam 2,
By restraining the bulging deformation of the 2' section, a sudden drop in strength after reaching the maximum strength is prevented, which greatly improves the earthquake resistance and deformation performance of the building using this shear wall, and reduces the cost of the building structure. It is possible to achieve this goal.

[Brief explanation of drawings]

Fig. 1 is a load deformation diagram of a shear wall, Fig. 2 is a reinforcing bar assembly diagram of an RC shear wall according to the first embodiment of the present invention, Fig. 3 is a sectional view taken along the - arrow in Fig. 2, and Fig. The figure is a reinforcing bar assembly diagram of the second embodiment, FIG. 5 is a model diagram simply showing another embodiment, and FIG. 6 is an explanatory diagram conceptually exaggerating the deformed state of the earthquake-resistant wall.

Claims (1)

[Scope of Claims] 1. In a reinforced concrete shear wall in which a reinforced concrete wall plate is integrally provided within a frame surface surrounded by reinforced concrete columns and beams, vertical reinforcing bars are provided on the wall plate 3. Large-diameter reinforcing bars 4 are firmly fixed at both ends to the beams 2, 2', and the shear force transmission capacity is increased to the portions of the wall plate 3 along the columns 1, 1' and the beams 2, 2'. A reinforced concrete shear wall characterized by the provision of easy-to-shear points with small shear. 2. In a reinforced concrete shear wall in which a reinforced concrete wall plate is integrally provided within the frame surface surrounded by reinforced concrete columns and beams, the beams 2, Large-diameter reinforcing bars 4 firmly anchored to 2' are arranged, and there are easily sheared areas with small shearing force transmission capacity in the parts of the wall plate 3 along columns 1, 1' and beams 2, 2'. The large diameter reinforcing bar 4 is provided.
A reinforced concrete shear wall characterized by having easy-to-shear points with low shear force transmission capacity in the vertical and longitudinal directions also in the parts along the .