JP2732238B2 - Connection structure of steel pipe pile and concrete footing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure between a steel pipe pile head and a concrete footing. Here, the steel pipe pile includes a steel pipe concrete portion in a cast-in-place steel pipe concrete pile, in addition to a steel pipe pile having a pile length formed of a steel pipe.

[0002]

2. Description of the Related Art Reinforcing steel is generally used as a steel material for connecting the head of a steel pipe pile and concrete footing.
No. 79350) and an extrapolation method (Japanese Utility Model Application Laid-Open No. 61-1735)
No. 54 gazette). In the interpolation method, as shown in FIG. 4, a plurality of reinforcing bars 10 are arranged in an annular shape and inserted into the hollow portion of the head of the steel pipe pile 11, and in the extrapolation method, as shown in FIG. The reinforcing bar 10 is fixed to the outer peripheral surface of the head of the steel pipe pile 11 in an annular shape.

The main function of these rebars 10 is to resist bending moments generated at the joints of the pile heads. The strength of the rebars is not only the cross-sectional area and the number of the rebars 10 but also the plurality of rebars 10. This 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 greater the reinforcing bar arrangement diameter, the greater the resistance to bending moment.

[0004] The above-mentioned interpolation method is excellent in construction workability, since it merely inserts an annularly reinforced cage into the hollow portion of the pile head. However, in order to secure the adhesion between the reinforcing bar 10 and the concrete 12 around the reinforcing bar 10, the reinforcing bar 10 and the steel pipe pile 1 are required.
It is necessary to keep the space with the inner peripheral surface of 1 sufficiently (for example, it is specified in the "Road Bridge Specifications" to be separated by more than the reinforcing bar diameter), and the reinforcing bar arrangement diameter is considerably smaller than the pile outer diameter. Becomes For this reason, there is a limit to the increase in the strength of the pile head joint with respect to the bending moment, and it may not be applicable to a building structure having a considerably large design bending moment.

[0005] In addition, among the vertical load of the upper structure, the reinforcing bar 1
The load shared at 0 is the concrete 1 around the reinforcing bar 10.
2 is transmitted to the steel pipe pile 11 via the second pipe 2, so that there is a disadvantage that the vertical load of the upper structure is not smoothly transmitted to the steel pipe pile 11.

In the extrapolation method, a plurality of reinforcing bars 10 are directly fixed to the outer peripheral surface of the head of the steel pipe pile 11 by welding.
The vertical load of the upper structure is smoothly transmitted to the steel pipe pile 11,
Further, since the rebar arrangement diameter is large, the strength against the bending moment can be set large. However, it is technically difficult to weld the outer peripheral surface of the head of the steel pipe pile 11 and the outer peripheral surface of the base end portion of the reinforcing bar 10 at a required penetration depth over a certain length. It is not easy to obtain good welding quality.

[0007] Further, since welding of such a form can be performed only by manual welding, it takes a long time to perform the operation, and it is difficult to shorten the construction period. There is also a drawback that becomes high.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the interpolation method and the extrapolation method, to increase the strength against bending moment and to smoothly apply the vertical load of the superposed structure to the steel pipe pile. An object of the present invention is to provide a joint structure between a steel pipe pile and a concrete footing that can transmit power and can easily perform welding work efficiently and with high welding quality.

[0009]

In the joint structure according to the first aspect of the present invention, a ring plate whose width is larger than the thickness of the steel pipe pile is welded to the end face of the head of the steel pipe pile so as to be orthogonal to the axis of the steel pipe pile. Then, a plurality of reinforcing bars whose diameters are set to be large within the range of the width of the ring plate are welded to the upper surface of the ring plate at a required interval to stand upright in parallel with the axis of the steel pipe pile, and footing so as to embed the entire length of the reinforcing bar. Pour concrete. Here, the width dimension of the ring plate is
The difference between the radius of the outer peripheral surface and the radius of the inner peripheral surface. In the connecting structure according to the second aspect of the present invention, the diameter of the reinforcing bar is set to be substantially equal to the thickness of the steel pipe pile.

The welding of the ring plate to the steel pipe pile is M
It is performed by complete penetration welding by a known means such as an automatic welding machine of the IG welding method. Since the ring plate is welded so as to be perpendicular to the axis of the steel pipe pile, even if the ring plate is welded at a factory, the steel pipe pile can be driven without any trouble. In addition, since the ring plate has an annular shape, even if the ring plate is welded and placed at a factory, it does not hinder the concrete placing and the like in the cast-in-place steel pipe concrete pile construction.

[0011] Similar to the welding of the ring plate to the steel pipe pile, the welding of the reinforcing steel to the ring plate is performed at a site or a factory by a known means such as an automatic welding machine of the MIG welding method. The base end of the reinforcing bar, which is perpendicularly butted to the upper surface of the ring plate, is welded to a sufficient depth. In both the welding of the ring plate and the welding of the rebar, the welding operation is performed by horizontal welding with the steel pipe pile laid down or vertical welding with the steel pipe pile upright depending on the construction sequence and construction place.

At the stage where the ring plate is welded to the steel pipe pile and the required number of rebars are welded to the ring plate, a mesh-shaped rebar of concrete footing is provided, and concrete is cast. Footing is combined. In addition, welding of a reinforcing bar to a ring plate can also be performed after arranging the mesh reinforcing bar of concrete footing according to construction conditions.

In this connection structure, since the reinforcing steel is welded to the end face of the steel pipe pile via the ring plate and stands upright in parallel with the axis of the steel pipe pile, the vertical load of the superposed structure is smoothly applied to the pile body. It is transmitted, and the transmission of the tensile force between them is also made well.

Since the reinforcing bars are arranged in the direction of extension of the end face of the pile head, the reinforcing bar arrangement diameter can be made larger than that of the above-mentioned interpolation method, but the reinforcing bar arrangement diameter is somewhat smaller than that of the extrapolation method. However, since the reinforcing steel is not welded directly to the head end face of the steel pipe pile, but is joined to the steel pipe pile via the ring plate, the width dimension of the ring plate is made larger than the thickness of the steel pipe pile, and accordingly By setting the reinforcing bar cross-sectional area large, the proof stress against the bending moment can be set sufficiently large.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment shown in FIGS. 1 and 2, the connecting reinforcing bar 1 is formed of a deformed reinforcing bar, and its base end is completely welded to the upper surface of the steel ring plate 2. The width dimension of the ring plate 2 is larger than the wall thickness of the steel pipe pile 3 and is completely welded and welded to the head of the steel pipe pile 3. The diameter of the reinforcing bar 1 is set to be substantially the same as the thickness of the steel pipe pile 3. The reinforcing bar 1 is welded so that the center of the reinforcing bar coincides with the center point of the thickness of the steel pipe pile 3. A cone head 5 is fixed in the hollow part of the head of the steel pipe pile 3 to prevent the footing concrete 4 from falling into the hollow part of the main body of the steel pipe pile 3.

The embodiment shown in FIG. 3 is applied to the steel-cast concrete part 7 of the cast-in-place concrete pipe 8 composed of the reinforced concrete part 6 and the steel-tube concrete part 7, and the footing concrete 4 is used for the cast-in-place steel pipe concrete pile 8. Of concrete 9 The ring plate 2 is welded to the head of the outer shell steel pipe of the steel pipe concrete part 7. The design of the transmission of the force between the reinforcing bar 1 and the footing concrete 4 is considered as a virtual reinforced concrete column.

[0017]

As described above, in the joint structure according to the first aspect of the present invention, a ring plate having a width larger than the thickness of the steel pipe pile is welded to the head end face of the steel pipe pile so as to be orthogonal to the axis of the steel pipe pile. Then, a plurality of reinforcing bars whose diameter was increased within the range of the width dimension of the ring plate ring were welded to the upper surface of the plate to stand upright parallel to the axis of the steel pipe pile, and footing concrete was poured to embed the entire length of the reinforcing bar. So
A large proof stress against bending moment can be secured, and the vertical load of the upper structure can be smoothly transmitted to the steel pipe pile.

In the joint structure according to the second aspect of the present invention, since the diameter of the reinforcing steel is made substantially equal to the thickness of the steel pipe pile, the strength against the bending moment is surely enhanced, and the vertical load on the upper structure is more accurately reduced. Is transmitted to the steel pipe pile.

Also, since a ring plate is welded to the head end surface of the steel pipe pile and the base end of the reinforcing bar is welded to the upper surface of the ring plate, a system for automatic welding can be easily designed. Therefore, high-quality welding can be performed efficiently without using skilled welders having high labor costs, thereby shortening the construction period and reducing construction costs.

[Brief description of the drawings]

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

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

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

FIG. 4 is a longitudinal sectional view of a joint portion between a steel pipe pile and a concrete footing using a conventional interpolation type joint structure.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reinforcing steel 2 Ring plate 3 Steel pipe pile 4 Concrete footing 5 Cone head 6 Reinforced concrete part of cast-in-place steel pipe concrete pile 7 Steel-cast concrete part of cast-in-place steel pipe concrete pile 8 Cast-in-place steel pipe concrete pile 9 Concrete of cast-in-place steel pipe concrete pile 10 Steel reinforcement 11 Steel pipe pile 12 Concrete footing 13 Reinforcing mesh of footing

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Tachikawa 2-6-1 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Steel Corporation (72) Inventor Etsuyoshi Yanagi 2--6, Otemachi, Chiyoda-ku, Tokyo No. 3 Inside Nippon Steel Corporation (72) Inventor Shigeru Hirami 2-6-2 Higashitenma, Kita-ku, Osaka City, Osaka Prefecture Inside Marugo Foundation Co., Ltd. (72) Inventor Yuji Matsuo Osaka City, Osaka Prefecture 2-6-2 Higashitenma, Kita-ku Marugo Foundation Industry Co., Ltd. (56) References Japanese Utility Model 5-16840 JP, U

Claims (2)

(57) [Claims] 1. A ring plate whose width is larger than the thickness of the steel pipe pile is welded to the head end face of the steel pipe pile so as to be orthogonal to the axis of the steel pipe pile, and the diameter is increased within the width of the ring plate. A plurality of set reinforcing bars are welded to the upper surface of the ring plate at required intervals to stand upright in parallel with the axis of the steel pipe pile, and a footing concrete is poured into the steel pipe pile so as to embed the entire length of the steel pipe pile and concrete. Footing coupling structure. 2. The joint structure according to claim 1, wherein the diameter of the reinforcing bar is set to be substantially equal to the thickness of the steel pipe pile.