JPS595074Y2 - Fixing bars for cylindrical metal fittings on PC concrete piles - Google Patents

Description

[Detailed description of the invention] PC concrete piles can be classified into disc type, annular type, and cylindrical type depending on where on the end fittings the PC concrete piles are welded and connected.

This invention is for completely fixing the cylindrical metal fittings of cylindrical PC concrete piles to concrete.

As shown in Figures 1 and 2, in the conventional disc type, a straight steel wire 4 was often used as an auxiliary reinforcing bar to prevent the disc metal fitting 1 from peeling off from the concrete 3. It was welded to the inner surface of the sheet metal fitting 1 or to the inner wall of the disk metal fitting 1 and the cylindrical metal fitting 2 made of a thin steel plate.

This was achieved only in the longitudinal direction of the straight steel wire 4 as an auxiliary reinforcement, which required an unnecessarily long wire, which was inconvenient in terms of handling and transportation.

The present invention mainly relates to cylindrical PC concrete piles, and since the PC concrete piles are welded together using cylindrical metal fittings 6 as shown in FIG. When something like this happens, the effect of the connection is lost.

Therefore, if the load from the lateral direction is applied to the entire PC concrete pile, it is safe because the load is not concentrated on the end metal fittings and the stress is distributed throughout the pile, but in extreme cases ,
That is, assuming a case where the lateral load W is concentrated on the end fitting as shown in Fig. 3, the welded part 7 of the end fitting serves as a fulcrum and a curve is placed on the left side 7' on the arc A-A line. This is caused by the cutting action of the welded part 7' and the peeling phenomenon between the cylindrical metal fitting 6 and the concrete frame 3 containing the PC steel wire 5.

In order to cope with the above external force, the present invention has a steel wire as a fixing reinforcement to the concrete frame of the cylindrical metal fitting 6 from the cylindrical metal fitting 6 on the above-mentioned arc A-A line as shown in Figs. 4, 5 and 6. 8 is installed.

That is, when a joint fitting is embedded in concrete using a straight or crank-shaped auxiliary reinforcement made of a single wire, it is done by adhering to the surface area of the auxiliary reinforcement, so it is necessary to make it long. cm~1
It is ranked m.

The present invention has a U-shaped, ■-shaped, L-shaped, ■-shaped, single-shaped, or U-shaped fixing bar 8 that is uniformly spread in the width direction and is 10 to 20 cm longer than the cylindrical metal fitting 6. The legs of the fixing bars 8 are attached to the inner wall of the cylindrical fitting 6 by welding, etc. to a rigid structure, and the tip is bent into a curved shape along the line A-A in Figure 3. The cylindrical metal fitting 6 and the concrete 3 are completely integrated by embedding and fixing them into the frame 3, including the width direction.

According to the present invention, as shown in Fig. 7, the concrete frame 3 itself is in a normal state where it is always under the compression action W' due to the pretension of the PC steel wire 5, so when a lateral load W is applied to the PC concrete pile. A stress W" is generated near the center line of the fixing bar 8 to prevent the concrete body 3 from peeling off and being pulled out from the cylindrical metal fitting 6, and when the lateral load W exceeds the breaking strength, the fixing bar 8 Concrete cracks will occur in section B, where there is no.

This satisfies the JIS standard requirement that the strength of the joint be equal to or greater than that of the main body.

In the present invention, the U-, V-, and U-shaped widthwise bones of the fixing bars 8, which have a strength equivalent to or greater than the hook portion of a reinforcing steel bar in a reinforced structure, perfectly embed and fix the concrete 3. It is extremely effective for strengthening the joints of PC concrete piles, and is highly workable and practical in that it does not require binding or welding of the fixing bars 8 to the PC steel wires 5.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional diagrams showing the reinforcement arrangement of auxiliary reinforcement 4 of conventional disc-type PC concrete piles. Figure 3 is a cross-sectional diagram of a cylindrical PC concrete pile.
Figure 4 is a schematic side view of a cylindrical metal fitting with fixing bars attached according to the present invention. Figures 5 and 6 are schematic bottom front views of the joints according to the present invention, and Figure 7 is a cross-sectional diagram showing the distribution of stress generated near the joints of PC concrete piles. 1...Disc metal fitting, 2...Cylindrical metal fitting, 3
...concrete), 4...auxiliary reinforcement, 5
...PC steel wire, 6...Cylindrical metal fittings for cylindrical PC concrete piles, 7...Welded parts between PC concrete piles, 8...Fixing bars .

Claims (1)

[Scope of utility model registration request] A rigid structure such as welding the legs of the fixing bars 8, such as U, ■, I, L, J, or U-shaped fixing bars 8 that are curved in advance and longer than the cylindrical portion 6 of the fitting, to the inner wall of the cylindrical fitting 6. This is a fixing bar for a cylindrical metal fitting in a PC concrete pile, which is characterized in that the cylindrical metal fitting 6 and the concrete 3 are integrated.