JPS6411796B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to cast-in-place reinforced concrete shear walls (hereinafter referred to as RC shear walls) that are mainly implemented in medium- and low-rise buildings, and more specifically, to This article concerns an RC shear wall that has a structure that allows for large deformation capacity without causing a decrease in the strength of the wall, hardly any evidence of failure on the wall's appearance, and that allows for easy calculation of resistance from the initial stage.

Conventional technology The mechanical properties of conventional shear failure type shear walls are as shown by the dotted line curve in Figure 2, which have high yield strength and rigidity, but it is difficult to calculate the yield strength, and the deformation at the maximum yield strength is small. After the maximum yield strength, it exhibits brittle fracture behavior that causes a rapid decrease in yield strength.
Deformation performance is poor.

Bending yield type shear walls are also known. This has excellent deformation performance and the calculation of the strength is easy, but in medium and low-rise buildings, it is inevitable to increase the number of main reinforcements in the columns. As a result, the properties are similar to those of the shear failure type shear wall described above, and in the case of a continuous shear wall, the shear strength will be low.

A flexible shear wall is known in which a column-beam frame and a precast wall plate are connected by a connector, and the deformation capacity is increased by utilizing the yielding and deformation of the connector. This is easy to calculate because the strength, rigidity, and deformation are determined by the connector (steel material), but it is time-consuming to attach the wall plate using the connector, and there is a gap between the column and beam frame and the wall plate. and is expensive.

A slit-type shear wall in which several slits are formed in the vertical direction of the wall plate is also known. Although this material has variable rigidity and is durable, the slits appear as scratches on the wall's appearance, and its strength is uncertain.

The earthquake-resistant wall described in Japanese Patent Publication No. 54-35006 consists of a precast wall board made by filling an opening surrounded by a reinforced concrete or PS concrete grid with weak mortar, etc., and connecting it to a column-beam frame. This is a structure in which the damping core is destroyed and the grid has a rigid frame-like property that provides a large deformation capacity.

The structure described in Japanese Patent Publication No. 54-28226 incorporates a vibration damping device that utilizes the resistance of a high-viscosity material within the plane of the column-beam frame to reduce the amount of vibration response (force, displacement, etc.) to earthquake force. The structure is said to improve earthquake resistance.

Problems to be Solved by the Invention [] The above-mentioned earthquake-resistant walls can only be implemented with precast wall boards, and cannot be implemented with cast-in-place concrete. Therefore, it takes time and money to transport the precast wall board, hang it, and attach it to the column-beam frame using connectors. Also,
The mechanical characteristics of the shear wall are such that when the damping core of the wall plate is destroyed, the proof stress temporarily decreases, and the deformation increases while the proof stress remains as it was when the grid started acting like a rigid frame. The destruction and damage to the wall panels in the process of reaching this strength is fatally obvious in appearance, and there is a problem in that repair work after an earthquake requires considerable cost and effort.

[] The above-mentioned vibration damping device is a mechanism or device for increasing the seismic resistance of a building and is incorporated into the frame, and is not a wall. Therefore, in order to make the exterior look like a wall, after installing the device in the plane of the column-beam frame, install a decorative wall in the plane of the frame as shown in Figures 3 and 4 of the same publication. There is a problem in that parts must be erected to cover the area.

Means for Solving the Problems As a means for solving the problems of the prior art described above, a reinforced concrete shear wall according to the present invention is provided, as preferred embodiments are shown in FIGS. 1 to 3 of the drawings. , Reinforced concrete wall plate 1 is placed within the frame surface surrounded by reinforced concrete columns 3, 3' and beams 4, 4'.
(a) Large diameter reinforcing bars 2 with both ends firmly anchored to columns 3 and 3' as horizontal transverse reinforcing bars in the horizontal direction in the middle of wall plate 1.
is installed, and easy shear points 7, 7 are installed in the wall board 1 at two upper and lower positions along the large diameter reinforcing bars 2 in the horizontal direction to induce horizontal sliding of the wall board.

(b) The horizontal wall reinforcement 6 of the same wall plate 1 has both ends connected to the columns 3,
3', and a wall plate and a column are installed vertically along the column 3 or 3' at a position between the tip of the wall transverse reinforcement 6 and the column 3 or 3'. An easy-to-separate point 7' is installed to induce tensile separation.

(c) The vertical wall reinforcement 5 of the wall plate 1 connects both ends to the upper and lower beams 4,
Each is characterized by being firmly fixed to 4'.

In addition, the above-mentioned shearing and tensile separation easy location 7
Specifically, this is carried out by laying a separating plate such as a Teflon (trademark) plate or by forming a joint in the wall plate or a cross-sectional defect or slit.

Operation As shown in the diagram of the principle of operation in Fig. 1, when horizontal force Q acts, horizontal sliding failure occurs at the easy-shearing point 7 (sliding surface) in the center of the wall plate, and the wall plate 1 has two upper and lower layers. The wall is separated into 1 ₁ and 1 ₂ shapes.
At the same time, the vertical tensile separation point 7' of the wall plate 1 and columns 3, 3' is separated by tensile force.
It is separated (divided) as shown in A'. However, wall board 1
Since the top and bottom of the wall board 1 and the beams 4 and 4' are integrated by the wall vertical reinforcement 5, the sliding division of the wall plate 1 or the separation from the column is hardly noticeable as a visible sign of the wall as it is hidden by the finishing cloth. There is no such thing.

In this way, the sliding on the sliding surface between the walls 1 ₁ and 1 ₂ , which are separated into two upper and lower parts, and the sliding between the wall plates 1 and 1,
Most of the shear deformation of the wall plate 1 can be absorbed by the bending and shear deformation of the 1/2 length portion (short pillar) of the columns 3 and 3' separated at point A', demonstrating a large deformation capacity. do.

In other words, the upper wall 1 ₁ separated as described above corresponds to a hanging wall, and the lower wall 1 ₂ corresponds to a waist wall, so this seismic wall can be divided into a pillar with a hanging wall and a pillar with a waist wall. It can be regarded as a composite structure, and if sufficient deformation performance is ensured in the short column parts where walls are not attached, even for columns with waist walls and columns with hanging walls, the occurrence of catastrophic earthquake damage to the building can be prevented. This means that it is possible.

On the other hand, a large shear strength Q is required for a seismic wall, and the large-diameter reinforcing bars 2 contribute to increasing the shear strength Q.

In other words, the horizontal shear force Q applied to this shear wall
is transmitted as the shear strength Q _C of the column 3 and the shear strength W 1 of the upper half wall 1 ₁ , where W ₁ is the tensile force T of the large diameter reinforcing bar 2 and the shear strength Q _C of the opposite column 3' _.
be transmitted and processed as such. The tensile force T of the large-diameter reinforcing bars 2 and the shear strength Q _C of the column 3' are determined by the shear strength W ₂ of the lower half wall 1 ₁ of the beam 4' on the lower floor.
and transmitted to the pillar for processing.

Therefore, the shear strength W ₁ , W ₂ of the vertically separated walls 1 ₁ , 1 ₂ is sufficiently larger than T + Q _C , and the columns 3, 3' have sufficient shear reinforcement to increase their shear strength Q _C. As long as it is assumed to be large, the yield strength Q of the shear wall is governed by the yield stress strength T of the large-diameter reinforcing bars 2, and is estimated by the formula Q=2Q _C +Q _S +T. however,
Q _S is the frictional force on the separation surface (sliding surface) of walls 1 ₁ and 1 ₂ .

In other words, the strength of the RC shear wall of this invention can be easily calculated from the above equation as the yield stress (strength) of the large-diameter reinforcing bars 2, and the strength gradually reaches the maximum strength, and even after that, the strength decreases. There is no such phenomenon, and the deformation continues to increase due to stable proof stress.

In addition, by arranging the yield stress of the large-diameter reinforcing bars 2 by the amount necessary for the target strength of the shear wall, the three types of load deformation curves Q ₁ , Q ₂ ,
As in Q ₃ , the purpose of load-bearing adjustment can be fully achieved.

On the other hand, the higher the shear strength _QC of the columns, the better, so even low- and medium-rise buildings will not approach shear failure type.

Example Next, embodiments of the invention will be described.

Figure 3 shows the reinforcing steel structure of the RC shear wall according to the present invention, in which the reinforcing bars of columns 3 and 3' are 4
Use D13 reinforcing bar for the main bar 3a of the book, and add φ
6 hoop reinforcements 3b are wound sufficiently densely to provide shear reinforcement.

The reinforcing bars of beams 4 and 4' are also D13 to the four main bars 4a...
The required amount of stirrup is wrapped around this reinforcing bar.

The vertical wall reinforcements 5 and the horizontal wall reinforcements 6 of the wall board 1 are made of φ4 reinforcing bars, and are configured as double reinforcements with an interval of 100 mm. In particular, all of the wall longitudinal reinforcements 5 are inserted into the beam reinforcing bars and firmly fixed, thereby integrating the wall board 1 and the beams 4, 4'. On the other hand, the wall transverse reinforcements 6 are arranged so that both ends thereof do not reach the left and right pillars 3, 3', but reach a position near them. Then, at a position between the tip of the horizontal wall reinforcement 6 and the column 3 or 3', a separation material such as Teflon (trademark) is used to form an easy point 7' that induces tensile separation of the wall plate and the column along the column. The board is placed vertically. Therefore, when an earthquake force is input, the wall plate 1 and the pillars 3, 3' are completely separated from each other at the easy-to-separate point 7' as shown in Fig. 1A and A'.

Next, two large-diameter reinforcing bars 2 are installed in parallel in the middle part of the wall plate 1 as horizontal horizontal reinforcing bars. 2
D19 reinforcing bars are used for the main large-diameter reinforcing bars 2, and both ends of the bars are inserted deeply into the reinforcing bars of the left and right columns 3 and 3' and firmly fixed. The tensile yield stress of this large diameter reinforcing bar 2 is 3900Kg/cm ² , so from the above equation Q = 2Q _C + Q _S + T, the strength of the RC shear wall is approximately 30 tons, and the deformation capacity is approximately 30/1
000, which can be clearly estimated and calculated.

In the figure, reference numeral 7 indicates easy shear points that induce horizontal sliding of the wall plate 1 at two positions above and below the large-diameter reinforcing bars 2, and these are separated by separating plates such as Teflon (trademark) with a thickness of about 2 mm. Two sheets stacked one on top of the other are installed along the upper and lower sides of the large-diameter reinforcing bars 2, approximately parallel thereto, with an interval of approximately 90 mm. Therefore, when an earthquake force is input to this seismic wall, sliding failure occurs in the horizontal direction at the center of the wall board 1 at the location of the easy shearing point 7, and the upper and lower 2
It is separated into two walls, and large-diameter reinforcing bars 2 are used.

This RC shear wall is completed by assembling reinforcing bars with the above structure and then pouring concrete on-site.

Effects of the present invention As described above in detail in conjunction with the examples, the reinforced concrete shear wall according to the present invention has a clear load-bearing mechanism from the beginning and is stable against increased deformation without causing a decrease in load-bearing strength. In addition, as a flip side effect, the destruction of wall panels does not cause any fatal external signs other than scratches due to slipping or separation; for example, it is not noticeable even if it is covered with decorative cloth, so it is possible to prevent damage caused by earthquakes. There is no particular need for repair afterward, which contributes to a reduction in repair costs and labor.

In addition, this shear wall can be easily constructed using concrete cast on-site.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the working principle of the RC shear wall according to the present invention, FIG. 2 is a load deformation diagram, and FIG. 3 is an assembly diagram of the reinforcing bars of the RC shear wall according to the present invention. 1... Wall plate, 1 ₁ , 1 ₂ ... Wall, 3, 3'... Column,
2... Large diameter reinforcing bars, 4, 4'... Beams, 5... Wall vertical reinforcements,
6... Wall transverse reinforcement, 7... Locations where shearing and tension separation is easy.

Claims (1)

[Claims] 1. Reinforced concrete columns 3, 3' and beams 4,
In a reinforced concrete shear wall consisting of a reinforced concrete wall plate 1 provided within the frame surface surrounded by 4', (a) horizontal horizontal reinforcing bars in the middle of the wall plate 1 at both ends to columns 3 and 3'; Strongly anchored large diameter reinforcing bars 2
are installed in the wall board 1 along the large-diameter reinforcing bars 2 at two positions above and below, where shearing is easy to induce horizontal sliding of the wall board 7, 7.
(b) The horizontal wall reinforcement 6 of the same wall plate 1 has both ends connected to the pillar 3,
3', and a wall plate and a column are installed vertically along the column 3 or 3' between the tip of the wall transverse reinforcement 6 and the column 3 or 3'. (c) The vertical wall reinforcements 5 of the wall board 1 have both ends attached to the upper and lower beams 4,
A reinforced concrete shear wall characterized by being firmly anchored to 4'. 2. The shearing and tensile separation points 7, 7' described in claim 1 are characterized in that they are provided by laying a separating plate, joining a wall plate, or forming a cross-sectional defect or slit. Reinforced concrete shear walls.