JPS626061B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a method of constructing floorboards.

In recent years, when constructing a floorboard, the lower part of the floorboard structure is
It consists of a PC board, which also serves as a driving formwork,
There is a tendency to adopt a method of constructing composite flooring by pouring cast-in-place concrete on top of this.
This is because this construction method is advantageous in terms of labor saving, material saving, and shortening the construction period.

By the way, when using this construction method, it is necessary to provide structural integrity so that the horizontal shearing force acting at the interface between the PC board and the cast-in-place concrete can be transmitted. One example of such a method is to use a PC board with a concave charcoal turret formed on its top surface, but conventionally known methods of this type are
The use of a PC board with a charcoal starter on the entire top surface caused the following inconveniences.

Because there is a concave shank in the center of the PC board laid as formwork, it is difficult to work on the PC board and there is a risk of tripping.

Now, if we consider the stress distribution of the floor plate surrounded by beams with reference to Figure 1, we will find that Figure a
When a distributed load w is applied, as shown in b, the bending moment M is large at the center, and the vertical shear force T is large at the periphery, as shown in c, and accordingly, the distribution of horizontal shear stress t at the interface is d The periphery becomes larger and the center becomes smaller. From this, it can be seen that even if a shear cylinder is provided in the center, the mechanical effect is weak, but in the past, a shear cylinder was also provided in the center where the effect was weak, so the processing cost of the shear cylinder was increased accordingly. This amounted to waste and affected construction costs.

As mentioned above, since there is a concave shear cotter in the center where the bending moment is large, the shear cotter becomes defective in its cross section.
The load that can be borne during construction work on PC boards has become smaller.

Because the width of the PC board is around 1m for transportation reasons, a joint for the PC board is required. Therefore,
Shacotta is only effective in one direction.

This invention was made in view of the above-mentioned circumstances, and by using a single piece of PC board that has a shear cotter only on the periphery along the beam and is flattened in the center, work in the center can be done more easily. Easy,
The purpose of the present invention is to provide a method for constructing floorboards that maintains work safety, can bear a large construction load on the PC boards, and can reduce construction costs.

This invention will be explained in detail below based on an embodiment shown in FIGS. 2 to 7.

In this invention, as shown in Fig. 2, in constructing a floor plate supported by the surrounding beam 1 or the beam side mold frame for the beam 1, the construction is carried out in the following steps. .

First, we started with the formwork that also serves as the lower part of the floorboard structure.
Lay the PC board 2 on the completed beam 1 as shown in Figure 3. This PC board 2 has one square grid (one section surrounded by beams 1 on all sides, that is, span x
It has a one-piece structure per span (span), and a plurality of concave shear cotters 3 are formed at the periphery of the upper surface, that is, at the periphery along the beam 1. These syringe starters 3 have a square shape with a size of 80 mm x 80 mm, have a depth of 4 to 8 mm, and are arranged in three rows around the PC board 2. In addition, each shampoo bottle 3 is
As shown in Figure 4, the side 3a closer to the beam 1 is in the direction where horizontal shear stress is generated (arrow I in Figure 3).
It is provided so as to be orthogonal to the arrow A direction in FIG. 4). In other words, the shear cylinder 3 is oriented so that each side of the cylinder cylinder 3 is parallel to the surrounding beams 1, so that the substantial bearing pressure area is large. Regarding the shape of this sheath cylinder 3, as shown in FIG.
It is formed so that a' (bearing pressure surface) is approximately vertical, so that a large bearing pressure can be maintained. By doing so, the predicted failure pattern of the shear cotter can be changed from a shear failure type to a bearing pressure failure type. As a result, brittle fracture can be avoided and a sticky structure can be created.

Note that the shape of the shearco starter 3 is not limited to that shown in FIG. 5;
As shown in FIG. 6, both inner surfaces may be sloped.

After laying the PC board 2 with such a configuration, it is used as a work floor and formwork, reinforcing bars 4 are placed on top of it as shown in FIG. 2, and cast-in-place concrete 5 is poured. Complete the floorboards. At this time, since no sheath starter is provided in the center of the PC board 2, the construction work is easy and safe.

As shown in FIG. 3, a plurality of hanging hooks 6 are provided on the top surface of the PC board 2. To briefly describe this with reference to FIG. It is formed by curving the reinforcing bar 7, and is provided so as to sink into a recess 8 formed on the upper surface of the PC board 2. When pouring the cast-in-place concrete 5, it is connected to the reinforcing bars 4 on the side of the cast-in-place concrete 5 that is orthogonal to the hanging hook 6, and prevents the upper plate made of the cast-in-place concrete 5 from lifting up from the PC board 2. It is now possible to prevent this. Furthermore, by connecting the hanging hook 6 to the upper reinforcing bars 4 in this manner, the integrity of the upper and lower concrete plates is enhanced, and the yield strength and maximum yield strength are also increased.

As explained above, according to the floor board construction method of the present invention, a single PC board that is laid as a formwork is used, which has a shear cotter only at the peripheral part along the beam and is flattened at the center. This makes construction work on the PC board easier, especially in the center, and eliminates the risk of tripping. Additionally, since there is no shear cotter that would cause cross-sectional defects in the center of the PC board, a large construction load can be borne on the PC board. Furthermore, since we use a PC board that actively eliminates the shear cotter from the central part, where mechanical effects are weak, the manufacturing cost of the PC board is also low, reducing overall construction costs.

[Brief explanation of the drawing]

Figure 1 is for explaining the stress distribution in the floorboard. Figure a shows the load distribution, Figure b shows the moment distribution, Figure c shows the distribution of vertical shear force, and Figure d shows the distribution of the vertical shear force. Figures 2 to 7, which show the distribution of shear stress at the interface, show an embodiment of the present invention. A plan view showing the installation process,
Fig. 4 is an enlarged view of part A in Fig. 3, Fig. 5 is an enlarged cross-sectional view taken along the - line in Fig. 4, Fig. 6 is a view similar to Fig. 5 showing a modified example of the shark starter, and Fig. 7 is an enlarged view of section A in Fig. 3. The figure is a sectional view showing how the hanging hook 6 is connected. 1... Beam, 2... PC board, 3... Sheaco star, 3a... Side near beam, 3a'... Inner wall, 5...
...cast-in-place concrete.

Claims (1)

[Scope of Claims] 1. A method of constructing a floorboard whose periphery is supported by beams, in which the lower part of the floorboard structure is constructed with a PC board, the PC board is first laid as a formwork, and then the PC
In the method of constructing a floor board by pouring cast-in-place concrete on a board, a single PC board with an integral structure is used, and this PC board has a plurality of recessed concrete blocks only on the periphery of the upper surface along the beam. A construction method for a floorboard, characterized in that the upper surface has a flat central part. 2. Each of the concave shear cotters has a rectangular shape with the side closer to the beam positioned so as to be substantially perpendicular to the direction in which horizontal shear stress is generated, and the inner wall of the shear cotter constituting the side closer to the beam is approximately vertical. A method of constructing a floorboard according to claim 1, wherein the floorboard is formed as follows.