JPH0634490Y2 - Structural floorboards - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a floorboard of a structure, particularly a floorboard formed by placing concrete on a PC board having a shear cotter formed on the top surface thereof. is there.

[Conventional technology]

As a floorboard that constitutes the floor of a building, a floorboard having a composite structure composed of a PC board and a concrete layer formed by being cast on the PC board using the PC board as a formwork has been widely adopted. ing.

A floorboard composed of such a PC board and a concrete layer must have structural integrity so that horizontal shearing forces acting on the interface with the concrete layer can be sufficiently transmitted to each other. Conventionally, it has been practiced to previously form a concave shear cotter on the upper surface of a PC plate.

5 and 6 show a floorboard constructed by using a PC board having such a shear cotter formed therein (Japanese Patent Publication No. 62-6061), in which reference numeral 1 is a beam and 2 is a beam. The PC board 3 supported by the beam 1 is a concrete layer formed by being cast on the PC board 2 and 4 is a reinforcing bar embedded in the concrete layer 3.

A large number of shear cotters 5 are formed in the peripheral portion of the upper surface of the PC plate 2 along the beam 1 so as to form a plurality of rows (three rows in the example shown in FIGS. 5 and 6). The central part of the plate is a flat surface. These Sharkotters are No. 7
As shown in FIGS. 8 and 9, generally, the side a has a square shape with a size of about 80 mm, and its depth d is 4 to 8 mm.
The dimension b between the shear cotters 5 is about 80 mm, which is the same as the dimension of the shear cotter itself (about 160 mm at the center interval of the holes at the pitch C).

The shear cotter 5 is oriented such that each side is parallel to the surrounding beam 1, and the inner wall surface 5a (bearing surface) near the beam 1 is formed to be substantially vertical. .
As a result, the bearing pressure can be kept large, and the predicted fracture pattern of the shear cotter is changed from shear fracture type to pressure bearing fracture type. As a result, brittle fracture can be avoided and a viscous structure can be created. Has become.

It should be noted that the shear cotter 5 is provided only on the peripheral portion without providing the shear cotter on the entire surface of the PC plate 2 because the horizontal shearing force generated at the interface between the PC plate 2 and the concrete layer 3 is large in the peripheral portion. Since it is small in the central part, it is enough to provide it in the peripheral part. Also, providing the shear cotter 5 in the central part of the PC plate where a large bending moment occurs causes unnecessary cross-section loss and bending force of the PC plate. Is reduced. Therefore, this PC board 2
In addition to being able to fully realize the integration with the concrete layer, the manufacturing cost of the PC board can be reduced compared to the case where a shear cotter is installed over the entire surface, and the shear cotter is installed in the center of the PC board. Since it is not present, there is an advantage that the risk of workers getting stuck is reduced and workability is improved.

[Problems to be solved by the invention]

However, in the above-mentioned conventional PC board, although there are advantages as described above, the required number of the shear cotters is still extremely large, and therefore, the shear cotters are provided in multiple rows in the peripheral portion of the PC board. As a result, it was sometimes difficult to secure a sufficiently large flat surface in the center of the PC board. For this reason, the manufacturing cost of the PC board cannot be sufficiently reduced, and the workability on the PC board is not always sufficiently improved.

This invention has been made in view of the above circumstances, and can sufficiently integrate the PC board and the concrete layer, and further reduce the required number of shear cotters provided on the PC board to sufficiently reduce the cost. In addition to being able to
It is an object of the present invention to provide a floorboard that can have a wide flat surface in the center of the PC board.

[Means for Solving Problems] The present invention is composed of a rectangular PC board supported by beams around the periphery and a concrete layer formed by casting on the PC board, and In the floor plate of the structure in which a large number of sheer cotters for increasing the integration with the concrete layer are formed on the upper surface of the PC board, the sheer cotter comprises a hole-shaped sheer cotter and a grooved sheer cotter, The hole type shear cotter is provided in the form of being concentrated near the four corners of the PC plate, and the groove type shear cotter is
It is characterized in that it is provided in the peripheral portion of the PC board so as to extend parallel to each other in the direction connecting the four adjacent corners of the PC board.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing the PC board 10 in the floor board of this embodiment. This PC board 10 is supported by the beam 1 and is used as a form, like the above-mentioned conventional PC board 2, and constitutes the lower part of the floor board.

A hole-shaped shear cotter 11 and a groove-shaped shear cotter 12 are formed on the upper surface of the PC board 10. Hole-shaped shear cotter
As shown in FIG. 1, 11 are provided so as to be concentrated near the four corners of the PC board (in the example shown in FIG. 1, forming 7 rows and 8 columns). The shapes and dimensions of these hole-shaped shear cotters 11 and the mutual intervals are the same as those of the conventional shear plate 5 in the PC board 2. As shown in FIG. The inner wall surface (bearing surface) 11a near 1 is substantially vertical.

Further, the groove-shaped shear cotters 12 are provided in a plurality of rows (four rows in the example shown in FIG. 1) so as to extend in parallel to the beam 1 in the direction connecting the four adjacent corners of the PC board 10 and in parallel with each other. There is. The groove width and depth of these groove type shear cotters 12 are equal to the size and depth of one side of the hole type shear cotter 11, and as shown in FIG. The inner wall surface (bearing surface) of is similar to the hole-shaped shear cotter 11 and is substantially vertical.

These groove-shaped shear cotters 12 are, so to speak, hole-shaped shear cotters continuously formed. Therefore, in these groove-shaped shear cotters 12, the bearing surface for the horizontal shearing force in the direction parallel to the length direction is Although not provided, the size of the bearing surface 12a against the horizontal shearing force in the width direction (direction orthogonal to the length direction) is the total of the bearing surfaces 11a of the hole-shaped shear cotters 11 formed in rows. It is larger than the area. For example, a hole-shaped sheer cotter that forms a row with one side having a length a and a mutual interval b equal to a, and a groove provided in a form in which the respective sheer cotters are continuous. With a shaped shear cotter, the bearing area is doubled. In other words, the same bearing area can be secured with half the number of rows.

As in the case of the conventional floor board, concrete is poured on the PC board 10 to form the concrete layer 3, and as shown in FIG. 4, the concrete is a hole-shaped sheer cotter 11 and a groove. PC board that goes into the shape-sharkotter 12
10 and the concrete layer 3 are integrated, and against the horizontal shearing force generated at the interface between the PC board 10 and the concrete layer 3, the shearing resistance of the part A, the shearing resistance of the part B, the parts C and C'in FIG. You will resist with the bearing capacity of.

In this PC board 10, since the hole-shaped sheer cotters 11 are concentrated near the four corners and the groove-shaped shercotter 12 is provided in the peripheral portion, the PC board 10 and the concrete layer 3 are formed. The horizontal shearing force generated at the interface of can be reliably transmitted, and sufficient strength can be secured. That is, when a vertical load is applied to the floor board of this embodiment, the PC board 10
A horizontal shearing force is generated at the interface between the concrete layer 3 and the concrete layer 3, and the horizontal shearing force is large in the peripheral portion of the PC board 10 and small in the central portion as described above. When the direction of the horizontal shearing force generated is further examined, the shearing force at the four corners of the PC board 10 is large in both the (a) direction and the (b) direction in FIG. In the central part of the periphery except for, a large shear force is generated only in the direction orthogonal to the beam, and the shear force in the direction parallel to the beam becomes small. That is, the four corners of the PC board 10 need to have sufficient shear strength in both directions, but the peripheral central portion of the PC board 10 must have sufficient shear strength only in the direction orthogonal to the beam. It will be good.

Based on the above, the floorboard of this embodiment is one in which the hole type shear cotter 11 and the groove type shear cotter 12 are formed. The shear cotter 11 is also responsible for horizontal shearing, while the shearing cotter 12 is responsible for horizontal shearing in the peripheral central part where the shearing force increases only in the direction orthogonal to the beam, and as described above, a large bearing surface is secured for that direction. , Will be able to exert sufficient proof strength.

As described above, in the floorboard of this embodiment, compared with the case where only the conventional hole-shaped shear cotter 5 is provided, the shear shearing force required while maintaining the same shear strength (that is, the same bearing area) is required. The number can be significantly reduced. Therefore, it is possible to secure a wider flat surface in the center of the PC board 10, improve workability, and secure strength against the bending moment of the PC board 10.
10 can be manufactured more easily and the manufacturing cost can be reduced.

The cross-sectional shapes of the hole-shaped shear cotter 11 and the groove-shaped shear cotter 12 are not limited to the above, and the inner wall surface (bearing surface) bearing pressure near the beam 1 may be slightly reduced but slightly tilted from a substantially vertical state. May be modified. Further, it goes without saying that the size and the number of the hole-shaped shear cotters 11 and the groove-shaped shear cotters 12 may be appropriately changed according to design requirements.

[Effect of device]

As described in detail above, the floorboard of the structure of the present invention is provided with hole-shaped shear cotters in a manner of being concentrated in the four corners of the PC board, and in the direction connecting the four corners of the PC board adjacent to each other in the peripheral portion of the PC board. Since the grooved sheer cotters are provided so as to extend to each other, the number of rows of the conventional holed sheer cotter can be reduced to about half. Therefore, it is possible to secure a sufficiently large flat surface in the center of the PC board, which makes it easier to perform construction work on the PC board, reduces the risk of tripping by workers, and ensures safe work. You can Further, since there is no shear cotter that causes a cross-section loss over a wider area in the central portion of the PC board, the construction load on the PC board can be more heavily beared. Furthermore, the structure of the PC board is simple, yet it is mechanically rational, the manufacturing cost of the PC board can be reduced, and the overall construction cost can be reduced.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention.
FIG. 1 is a plan view showing a laying state of a PC board, FIG. 2 is an enlarged sectional view of a hole type shear cotter along line II-II in FIG. 1, and FIG. 3 is line III-III in FIG. FIG. 4 is an enlarged cross-sectional view of the grooved shear cotter along the line, and FIG. 4 is a diagram for explaining the relationship between the horizontal shearing force in the floor plate and the grooved shear cotter. 5 to 8 show a conventional example, FIG. 5 is a perspective view of a structural floor board, FIG. 6 is a plan view showing a laid state of a PC board, and FIG. 7 is a portion A of FIG. Fig. 8 is an enlarged view of Fig. VIII-VI.
It is an expanded sectional view which follows II. 1 …… Beam, 10 …… PC board, 3 …… Concrete layer on PC board, 11 …… Hole type shear cotter, 12 …… Groove type shear cotter.

Claims (1)

[Scope of utility model registration request] 1. A rectangular PC board having a perimeter supported by beams and a concrete layer formed by being cast on the PC board, and the concrete is formed on the upper surface of the PC board. In a floorboard of a structure in which a large number of shear cotters for enhancing integration with layers are formed, the shear cotters consist of hole-shaped shear cotters and groove-shaped shear cotters, and the hole-shaped shear cotters are the PC boards. It is provided in the form of being concentrated near the four corners.
A floorboard of a structure, characterized in that it is provided in a peripheral portion of a PC board so as to extend in parallel to each other in a direction connecting four adjacent corners of the PC board.