JPH0971949A - Combination structure of steel-pipe pile and concrete footing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit the vertical load of a placing structure smoothly to a pile body by welding the support leg sections of reinforcing bars onto the outer circumferential surface of the head section of a steel-pipe pile and disposing the main body sections of the reinforcing bars in upright in parallel with the axis of a steel-pipe pile. SOLUTION: Reinforcing bars consist of main body sections parallel with the axis of a steel-pipe pile and support leg sections inclined to the axis, and the lower end sections of the support leg sections are welded onto the outer circumferential surface of the head section of the steel-pipe pile. In the deformed bars 1 for combination, the main body sections 2 and the support leg sections 3 are connected continuously at an obtuse angle, and the main body sections 2 are overhung largely to the outside of the steel-pipe pile 4. A cone head 6 is fixed into the hollow section of the head section of the steel-pipe pile 4, a plurality of reinforcing bars inhibiting falling-in to the hollow section of the main body of the steel-pipe pile 4 of footing concrete 5 are arranged in an annular ring shape, the support leg sections of the reinforcing bars are welded onto the outer circumferential surface of the head section of the steel-pipe pile, and footing concrete is placed so as to bury the overall length of the reinforcing bars, thus increasing yield strength against bending moment, then widening the mutual spaces of the main body sections and facilitating bar arrangement operation.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a joint structure between a head of a steel pipe pile and a concrete footing. Here, the steel pipe pile includes a steel pipe concrete portion in a cast-in-place concrete pipe pile, in addition to the steel pipe pile whose entire length is made of steel pipe.

[0002]

2. Description of the Related Art Reinforcing bars are generally used as a steel material for connecting the heads of steel pipe piles and concrete footings.
No. 0) and an extrapolation method (Japanese Utility Model Laid-Open No. 61-173554). As shown in FIG. 4, the interpolating method is to arrange a plurality of reinforcing bars 11 in an annular shape and insert the reinforcing bars 11 into the hollow portion of the head of the steel pipe pile 12 in parallel with the axis of the steel pipe pile. As shown in, a plurality of reinforcing bars 11 parallel to the axis of the steel pipe pile
Is fixed to the outer peripheral surface of the head of the steel pipe pile 12 in an annular shape.

The main function of these reinforcing bars 11 is to resist bending moments generated at the pile head joints, but the proof stress is not limited to the cross-sectional area of the reinforcing bars 11 and the number of arranged bars, but also to connect a plurality of reinforcing bars 11. As a result, the diameter also varies depending on the diameter of the ring drawn in the horizontal plane (hereinafter referred to as the reinforcing bar arrangement diameter), and the larger the reinforcing bar arrangement diameter, the greater the proof stress against bending moment.

The above-mentioned interpolating method is excellent in workability because it only inserts the annular reinforcing bar cage into the hollow portion of the pile head. However, in order to secure the adhesive force between the reinforcing bar 11 and the surrounding concrete 13, the reinforcing bar 11 and the steel pipe pile 1
It is necessary to arrange it with a sufficient space between it and the inner peripheral surface of 2 (for example, in the "Road Bridge Specifications", it is specified that it should be separated by more than the diameter of the reinforcing bar), and the diameter of the reinforcing bar is considerably smaller than the outer diameter of the pile Becomes Therefore, there is a limit to the increase of the proof stress against the bending moment of the pile head joint, and it may not be applicable to a building structure having a considerably large design bending moment.

Of the vertical load of the overlaid structure, the reinforcing bar 1
The load shared by 1 is the concrete 1 around the rebar 11.
Since it is transmitted to the steel pipe pile 12 via 3 the vertical load of the overlaid structure may not be smoothly transmitted to the steel pipe pile 12.

In the extrapolation method, since the plurality of reinforcing bars 11 are directly fixed to the outer peripheral surface of the head of the steel pipe pile 12 by welding,
The vertical load of the mounted structure is smoothly transmitted to the steel pipe pile 12,
Further, since the diameter of the reinforcing bar arrangement is large, the proof stress against bending moment can be set large. However, it is technically difficult to weld the outer peripheral surface of the head portion of the steel pipe pile 12 and the outer peripheral surface of the base end portion of the reinforcing bar 11 that are in line contact with each other on a curved surface with a required penetration depth over a certain length. , Getting good welding quality is not easy.

Further, since the welding of such a form can be performed only by hand welding, it takes a long time to perform the work, and it is difficult to shorten the construction period. There is also a drawback that it becomes high.

As an intermediate method between the interpolating method and the extrapolating method, as shown in FIG. 6, the lower ends of a plurality of reinforcing bars 11 arranged in an annular shape parallel to the axis of the steel pipe pile 12 are connected to the plate thickness of the steel pipe pile 12. Welding is also performed at a right angle to the head end face of the steel pipe pile 12 at the center, but since the reinforcing bar cross section that defines the welded shape is a right cross section perpendicular to the reinforcing bar center line, it is also possible to obtain a strong joint strength. There is a certain limit.

[0009]

An object of the present invention is to increase the proof stress against bending moment, to smoothly transmit the vertical load of the overlaid structure to the steel pipe pile, to perform welding work efficiently, and to improve the joint strength. It is to provide a large, steel pipe pile and concrete footing joint structure.

[0010]

Means for Solving the Problems In a joint structure for a steel pipe pile and a concrete footing according to the present invention, a main body portion parallel to an axis of the steel pipe pile and a supporting leg portion continuously connected to a lower end of the main body portion and inclined with respect to the axis line. A plurality of rebars consisting of and are arranged in an annular shape, the lower end of the supporting leg portion is obliquely welded to the outer peripheral surface of the head of the steel pipe pile, and footing concrete is placed so as to embed the entire length of the rebar.

Welding of the reinforcing bar to the steel pipe pile is carried out by complete penetration welding by a known means such as an automatic welding machine of the MIG welding method. Since the reinforcing bars are welded to the outer peripheral surface of the steel pipe pile in an oblique direction, it is possible to sufficiently cope with changes in the construction procedure. Reinforcing bar welding work is performed by horizontal welding in which steel pipe piles are laid down or vertical welding in which steel pipe piles are erected at a factory or a construction site depending on the construction order and construction site.

At the stage where the required number of reinforcing bars are welded to the steel pipe pile, the mesh reinforcing bars of concrete footing are arranged and the concrete is placed, whereby the steel pipe pile and the concrete footing are connected. It should be noted that the welding of the reinforcing bar to the steel pipe pile may be performed after the installation of the reticulated reinforcing bar of the footing, depending on the construction conditions.

In this joint structure, the supporting leg portion of the reinforcing bar is welded to the outer peripheral surface of the head of the steel pipe pile, and the main portion of the reinforcing bar stands upright in parallel with the axis of the steel pipe pile. It is smoothly transmitted to the main body, and the tensile force is mutually well transmitted.

[0014]

DETAILED DESCRIPTION OF THE INVENTION In the embodiment shown in FIGS.
The connecting reinforcing bar 1 is composed of deformed reinforcing bars, and the main body portion 2 and the supporting leg portion 3 are connected to each other at an obtuse angle, and the main body portion 2 is a steel pipe pile 4
Overhangs to the outside. A cone head 6 is fixed in the hollow portion of the head of the steel pipe pile 4 to prevent the footing concrete 5 from falling into the hollow portion of the main body of the steel pipe pile 4.

The embodiment shown in FIG. 3 is applied to the steel pipe concrete portion 8 of the cast steel pipe concrete pile 9 composed of the reinforced concrete portion 7 and the steel pipe concrete portion 8, and the footing concrete 5 is the cast steel pipe concrete pile 9. It has been spliced together with the concrete 10. The supporting leg portion 3 of the reinforcing bar 1 is welded to the outer peripheral surface of the outer shell steel pipe of the steel pipe concrete portion 7.

[0016]

As described above, in the coupling structure of the present invention,
Multiple reinforcing bars are arranged in an annular shape, the supporting legs of the reinforcing bars are welded to the outer peripheral surface of the head of the steel pipe pile, and footing concrete is placed so as to fill the entire length of the reinforcing bars, so it is possible to increase the resistance to bending moments. The vertical load of the mounted structure can be smoothly transmitted to the steel pipe pile.

The reinforcing bar is composed of a main body portion parallel to the axis of the steel pipe pile and a supporting leg portion inclined with respect to the axis line. Since the lower end portion of the supporting leg portion is welded to the outer peripheral surface of the head of the steel pipe pile, the main body portion of the reinforcing bar is Since the diameter of the reinforcing bars arranged by connecting them is enlarged and the diameter of the virtual concrete column is increased, a rational design can be performed according to the construction conditions.

Further, since the interval between the main parts of the reinforcing bar is widened, the reinforcing work of the concrete footing is facilitated, and the main part of the reinforcing bar is upright.
Eliminates or significantly reduces interference with concrete footing rebar.

Since the lower end portion of the supporting leg portion of the reinforcing bar is obliquely welded to the outer peripheral surface of the head of the steel pipe pile, the workability of welding is good, and the reinforcing bar cross section which defines the shape of the welding part with the steel pipe pile has the reinforcing bar center line. Since the cross section has an obtuse angle with respect to the cross section, and this cross section has a larger area than the true cross section, the welding strength increases and the joint strength increases.

[Brief description of drawings]

FIG. 1 is a perspective view of a head portion of a steel pipe pile according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a joint portion between the steel pipe pile and the concrete footing shown in FIG.

FIG. 3 is a vertical cross-sectional view of a joint portion between a cast-in-place concrete pile and a concrete footing according to another embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of a joint portion between a steel pipe pile and a concrete footing using a conventional interlocking joint structure.

FIG. 5 is a vertical cross-sectional view of a joint portion between a steel pipe pile and a concrete footing using a conventional extrapolation type joint structure.

FIG. 6 is a vertical cross-sectional view of a joint portion between a steel pipe pile and a concrete footing using a conventional joint structure of another type.

[Explanation of symbols]

 1 Reinforcing bar 2 Main part of reinforcing bar 3 Reinforcing bar part 4 Steel pipe pile 5 Concrete footing 6 Cone head 7 Reinforced concrete part of cast steel pipe concrete pile 8 Steel pipe concrete part of cast steel pipe concrete pile 9 Cast steel pipe concrete pile 10 Cast steel pipe Concrete for concrete pile 11 Reinforcing bar 12 Steel pipe pile 13 Concrete footing 14 Reticulated rebar for footing

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Misao Kusumoto 2-6-3 Otemachi, Chiyoda-ku, Tokyo Within Nippon Steel Corporation (72) Inventor Yoshiyuki Era 3--14, Kyohei, Sumida-ku, Tokyo No. 4 Okabe Tech Co., Ltd.

Claims (1)

[Claims] 1. A plurality of reinforcing bars, each of which is composed of a main body portion parallel to the axis of the steel pipe pile and a support leg portion which is connected to the lower end of the main body portion and is inclined with respect to the axis line, is arranged in an annular shape. A joint structure of a steel pipe pile and a concrete footing, characterized in that a lower end portion is obliquely welded to an outer peripheral surface of a head portion of a steel pipe pile, and footing concrete is placed so as to fill the entire length of the reinforcing bar.