JPH0439295Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a joint fitting for hollow concrete piles.

[Prior art]

Ready-made PC concrete piles are usually constructed with a length of 10m to 15m, and when a longer pile is required, two or more ready-made PC concrete piles are connected using joint fittings. It is used as

FIG. 2 is a sectional view showing an example of a concrete pile 2 to which a conventional joint fitting 1 is attached. PC is
The ends of the PC steel wires are attached to the fitting 1, and the attachment points are arranged in a substantially circular manner inside the circumferential circle of the bottom of the fitting 1.

FIG. 3 shows an enlarged cross section of the above-mentioned joint fitting 1.
This joint fitting has a washer-like bottom plate 1 with a hollow hole.
A and a cylindrical ring 1b are constructed separately and connected by welding. 1c is a welding beat.

The ring 1b has two cylindrical groove-shaped recesses 1.
b _-1 and 1b _-2 are provided. This circumferential groove-shaped recess 1
By providing b _-1 and 1b _-2 , protrusions are formed on the inner circumferential surface of the recess, and the connection to the concrete pile is strengthened.

[Problem that the invention attempts to solve]

In order to reduce material costs and processing costs, it is desirable that the above-mentioned joint fittings be made as thin as possible within a range that satisfies a predetermined strength. However, when the concrete piles 2 are joined together as shown in Fig. 4 and the fittings 1 are welded together, when a test load P ₁ is applied to both sides of the fittings 3 and 3' while supporting the fittings 1, The breaking moment must not be smaller than the breaking moment when a test load P ₂ is applied to a part without fittings supported by supporting points 4 and 4' (internal industry regulations).
Therefore, the bottom plate 1a must have a suitable thickness.

FIG. 5 shows a conventional sole constructed to be as light as possible and have a predetermined strength.
It is an explanatory diagram depicting a cross section of a'.

1a _-1 has a groove for welding.

However, even if the configuration shown in Fig. 5 is used, one reason is to maintain the strength of the bottom plate itself;
In order to obtain the dimension a _-2 (i.e. to maintain the strength of the weld),
There is a limit to the reduction of the wall thickness dimension t.

This idea was created in view of the above circumstances.
The purpose is to provide a joint fitting for PC concrete piles that can maintain sufficient bottom plate strength and sufficient weld strength, and has an improved bottom plate shape that can significantly reduce the plate thickness. This is what I am trying to do.

[Means for solving problems]

In order to achieve the above object, the joint fitting of the present invention is a joint fitting for hollow PC concrete piles, which has a structure in which a bottom plate with a central hole in the shape of a washer is welded and fixed to a cylindrical ring. It is pressed so that the cross section along the plane including the center line forms an L-shape, and the peripheral part of the bottom plate that forms one side of the L-shaped cross section is folded up to form a short cylindrical part. The outer diameter of the short cylindrical portion is equal to the outer diameter of the concrete pile, the length L' of the cylindrical portion is approximately twice the thickness T of the bottom plate, and the bottom plate with the washer-shaped center hole is The inner diameter of the center hole is equal to the inner diameter of the concrete pile, and the thickness t of the cylindrical ring is much thinner than the thickness T of the bottom plate, and the ring is attached to the cylindrical part of the bottom plate. It is characterized by being butt welded.

[Effect]

In the joint fitting configured as described above, the short cylindrical portion acts as a reinforcing rib, and exhibits high rigidity compared to the plate thickness dimension. Furthermore, the roundness of the corner of the bent part (so-called radius) caused by press processing
Since the groove serves as a welding groove, a sufficient groove can be obtained compared to the plate thickness dimension, and therefore sufficient welding strength can be exhibited.

〔Example〕

FIG. 1 is an explanatory diagram schematically depicting a cross section of one embodiment of a joint fitting according to the present invention.

1c is a bottom plate constructed by applying the present invention, in which a washer-shaped steel plate having a center hole is pressed so that its cross section is L-shaped (for details,
The concrete pile 2 is formed so that its cross section along the plane including the center line Y-Y' is L-shaped), and a short cylindrical folded-up edge 1c _-1 is provided on its outer periphery.

The length L′ of the short cylindrical folded-up edge 1c _-1 is:
The thickness is approximately twice the thickness T of the bottom plate. If this dimension L' is significantly smaller than 2T, sufficient strength cannot be expected.

Moreover, if it is significantly larger than 2T, it is uneconomical because the increase in strength is small even though press forming is difficult.

The ring 1b is opposed to the short cylindrical folded-up edge 1c _-1 and butt welded. In the above ring, the thickness t of the ring 1b is much thinner than the thickness T of the bottom plate 1c. Here, extremely thin means that it is so thin that it can be visually judged without using a meter.

The bent portion naturally has a roundness with a radius of curvature r. 1c _-2 is a welded portion between the bottom plate 1c and the ring 1b.

As shown by the imaginary line, when the bottom plate 1c' attached to another concrete pile 2' is opposed to the bottom plate 1c, the part with the radius of curvature r formed by the above-mentioned press forming forms a groove. It can be welded with sufficient strength.

Furthermore, the bottom plate 1c has a structure in which the short cylindrical portions 1c _-1 are integrally connected, rather than having a flat washer shape, and therefore has high rigidity.

[Effect of idea]

As detailed above, when the present invention is applied, it has the excellent practical effect of being able to significantly reduce the thickness of the bottom plate while ensuring sufficient rigidity and welding strength for the fitting. This greatly contributes to making concrete piles lighter and cheaper.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of one embodiment of the present invention. FIGS. 2 and 3 are explanatory diagrams of conventional concrete pile joint fittings, and FIG. 4 is an explanatory diagram of a concrete pile strength test. Fifth
The figure is an explanatory view of a bottom plate in a joint fitting according to the prior art. 1... Fittings, 1a, 1a'... Bottom plate, 1a _-1
...Bevel, 1b...Ring, 1c...Bottom plate, 1
c _-1 ...Folded upper edge of short cylindrical shape, 1c _-2 ...Welded part, 2,
2'...Concrete pile, 3, 3', 4, 4'
……fulcrum.

Claims (1)

[Scope of Claim for Utility Model Registration] A metal fitting for hollow PC concrete piles having a structure in which a bottom plate with a center hole provided on a washer is welded and fixed to a cylindrical ring. is pressed into an L-shape, and the peripheral part of the bottom plate forming one side of the L-shaped cross section is folded up to form a short cylindrical part, and the outer diameter of the short cylindrical part is is equal to the outer diameter of the concrete pile, the length L' of the cylindrical portion is approximately twice the thickness T of the bottom plate, and the inner diameter of the center hole of the bottom plate provided with the washer-shaped center hole is equal to the diameter of the concrete pile. is equal to the inner diameter of the cylindrical ring, the thickness t of the cylindrical ring is much thinner than the thickness T of the bottom plate, and the ring is butt-welded to the cylindrical part of the bottom plate. Hollow PC concrete pile joint fittings.