JP2003074072A - Pile head joining structure of steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile head structure superior in workability, reducing a cost, improving efficiency, and resistible even against tensile force. SOLUTION: Pile head hardware is manufactured by welding an anchor reinforcement to the outer periphery of a cylindrical lid body having the blocked-up upper end, and having a plurality of hook-shaped slits on the peripheral surface lower end. This pile head hardware is driven in the ground, and is put from above on a head part of a steel pipe pile having a plurality of projecting pieces in the vicinity of an upper end part so that the projecting pieces engage with the hook-shaped slits. Concrete of footing is placed, and the head part of the steel pipe pile is joined to the footing in a state of not practically contacting with the concrete of the footing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a joint between a pile head of a steel pipe pile and a pile head concrete such as footing.

[0002]

2. Description of the Related Art It is common to think that the pile head of a steel pipe pile is rigidly connected to pile head concrete such as footing.
Conventionally, as a pile head structure for that purpose, the structure shown in FIGS. 4 to 6 has been generally used. In addition, Japanese Patent Laid-Open No. 2000-
There is also a structure disclosed in Japanese Patent No. 154536 or Japanese Patent Laid-Open No. 11-280063. The structure of FIG. 4 is footing 1
The pile head of the steel pipe pile 2 is embedded in the pile for a certain length L ≧ D (L is the embedding length, D is the outer diameter of the pile), and the bending moment, horizontal force, and pullout that act on the pile head at the embedded portion It resists external force such as force. In the structures of FIGS. 5 and 6, the embedded length of the steel pipe pile 1 in the footing 2 is kept to a minimum, and the steel pipe pile 1 is reinforced mainly by reinforcing bars so as to resist external force acting on the pile head.

In the structure disclosed in Japanese Patent Laid-Open No. 2000-154536, almost no steel pipe pile is embedded in the footing, and the upper end of the steel pipe pile is welded to the base plate anchored to the footing by the integrated reinforcing bar. It resists the external force acting on the pile head. On the other hand, the structure disclosed in JP-A-11-280063 is
Almost no steel pipe pile is embedded in the footing, and the upper end of the steel pipe pile is fitted into the tubular lid anchored to the footing by the integrated reinforcing bar to resist external force acting on the pile head. .

In the structures shown in FIGS. 4 and 5, it is troublesome to mount the slip stoppers 10 on the inner surface of the steel pipe pile 2,
Particularly when the inner diameter of the steel pipe pile 1 is small, fillet welding becomes difficult. Further, even with the structure of FIG. 6, it is difficult to fillet weld a large number of different diameter reinforcing bars to the outer peripheral surface of the steel pipe pile at the construction site.
On the other hand, the structure disclosed in Japanese Patent Laid-Open No. 2000-154536 makes it extremely difficult to weld the steel pipe pile and the base plate on site.

Further, in the structure disclosed in Japanese Patent Laid-Open No. 11-280063, when the pile head is simply fitted into the lid, the pulling force acting on the pile head cannot be resisted. In order to have a structure that can resist the pulling force, it is necessary to integrate the pile head and the lid by welding, etc., or to make the pile head and the inside of the lid screwed together. Can be cumbersome or uneconomical. Furthermore, in any of the above-mentioned structures, the structure is basically to rigidly connect the pile head, and when a horizontal force acts on the pile head, a large bending moment is generated in the steel pipe pile main body, so the steel pipe pile main body It becomes uneconomical because the thicker one is required.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and an object thereof is to provide a pile head structure which is excellent in workability, inexpensive, and efficient.

[0007]

The pile head structure according to claim 1 of the present application is applied to a pile head of a steel pipe pile driven in the ground and having a plurality of convex pieces near the upper end, A cylindrical head body having an inner diameter larger than the outer diameter, closed at the upper end, and having a plurality of hook-shaped slits at the lower end of the peripheral surface, and a pile head metal member composed of a fixing rebar integrated with the lid body -Shaped piece and the hook-shaped slit are covered so as to be engaged with each other, and the pile-head concrete such as footing and the steel pipe pile do not come into direct contact with a portion other than the hook-shaped slit of the pile-head metal object lid. It is a thing.

Since the steel pipe pile head hardly contacts the pile head concrete such as footing, a large bending moment is not generated in the steel pipe pile main body even if a horizontal force acts without a rigid connection. Here, the pile head concrete such as footing adheres to the steel pipe pile body through the hook-shaped slits formed in the lid of the pile head hardware, but the adhesion hardened portion is only a part and does not form a rigid connection. In addition, some of the adhesion hardened parts peel off at an early stage during use after hardening of concrete,
In practical use, the steel pipe pile head does not come into contact with footing concrete.

Further, since the convex piece of the steel pipe pile head and the hook-shaped slit of the lid of the pile head metal fitting are engaged with each other, sufficient resistance against pulling force is exerted. If the convex piece of the steel pipe pile head is engaged with the hook-shaped slit of the pile head hardware lid,
The material and shape are not particularly limited, but it is common and preferable to simply fillet weld a plurality of square steels of a predetermined size to the pile head of the steel pipe pile, which is simple and convenient. If the inner diameter of the cover of the pile head metal is too close to the outer diameter of the pile head, it will be extremely difficult to cover the steel pipe pile head with the pile head metal, and the bending moment generated when a horizontal force is applied will be large. Therefore, the inner diameter of the lid is preferably larger than the outer diameter of the pile head by 2 mm or more.

On the other hand, if the inner diameter of the lid is excessively large as compared with the outer diameter of the pile head, a convex piece with a high projection height is inevitably required, and the structural strength of the member becomes extremely large. The inner diameter of the lid is preferably 20 mm or less than the outer diameter of the pile head. According to a second aspect of the present invention, in the pile head structure according to the first aspect, an insulating cushioning material is interposed between the inside of the lid of the pile head hardware and the outside of the head of the steel pipe pile.

By installing the insulating cushioning material at least inside the side surface of the cover of the pile head metal and, if necessary, inside the upper surface of the cover body, the rigidity of the steel pipe pile and the pile head concrete is surely lowered, and the steel pipe is It is possible to prevent the occurrence of a large bending moment at the pile head. In addition, the interposition of insulating cushioning material reduces the vibration transmission to the upper structure supported by the steel pipe pile, and even when there is a stray current in the surrounding ground, the pile head hardware cover and the steel pipe pile head. It also suppresses the electrolytic corrosion that occurs in the vicinity of the joint.

The insulating cushioning material is most preferably a rubber sheet or the like. The pile head structure according to claim 2 can be provided by attaching a rubber sheet or the like to the inside of the lid of the pile head hardware with a rubber adhesive. Its action or function is as described above, and it is simple enough to engage the hook-shaped slits of the lid of the pile head metal fitting with the anchoring rebars with a plurality of convex pieces of the steel pipe pile head. It has a basic structure, and even if an insulating cushioning material is interposed between the lid and the steel pipe pile head, it can be mass-produced at low cost.

[0013]

1 shows one embodiment of the pile head structure of the present invention, and FIG. 2 shows an insulating cushioning material interposed between the pile head metal lid and the steel pipe pile head of the present invention. 3 illustrates an embodiment in the case of being allowed to do so. As shown in FIGS. 1 and 2, the pile head hardware according to the present embodiment is formed by welding a plurality of fixing rebars to the outer periphery of a cylindrical lid body having an upper end closed, and a lower end portion of the lid body. There are multiple hook-shaped slits.

[0014] This pile head hardware is put on a steel pipe pile head having a plurality of convex pieces on the pile head placed in the ground so that the hook-shaped slit and the convex piece engage with each other from above. By placing footing concrete, a pile head structure as shown in FIG. 1 is obtained. In the present embodiment, the bent reinforcing bar as described above is used as the anchor reinforcing bar of the pile head metal, but a hoop reinforcing bar may be further attached to this or a strip steel or the like may be used as an anchor member.

Further, a pile head structure as shown in FIG. 3 can be obtained by previously attaching a rubber sheet having a thickness of 5 mm as an insulating cushioning material inside the lid of the pile head hardware. Also,
This embodiment is a case where the pile is a steel pipe pile, but it can be similarly applied to a case where an outer shell steel pipe concrete pile is used for the upper pile.

[0016]

[Effects of the Invention] In the field work, the head of the cast steel pipe pile is covered with the pile head hardware, and the hook-shaped slit of the pile head hardware lid and the convex piece of the steel pipe pile head are engaged. Yes, it is easy to install. Since a gap or an insulating cushioning material is present between the pile head hardware and the steel pipe pile head, a large bending moment does not occur in the steel pipe pile main body, and it is not necessary to increase the wall thickness of the steel pipe pile, which is economical. Construction is easy because there is no welding to prevent slippage or other troublesome on-site work.

It is possible to easily provide a structure that resists the pulling force only by engaging the hook-shaped slit and the convex piece. If an insulating cushioning material is used, vibration transmission to the upper structure is reduced.
It is possible to suppress the electrolytic corrosion of the steel pile head structure part. For the above reasons, a low cost pile head joint can be provided quickly and easily.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a pile head joint structure of the present invention.

FIG. 2 shows an embodiment of the pile head joint structure of the present invention,
(B) is a front view and (a) is a plan sectional view.

FIG. 3 is a vertical sectional view showing an embodiment of a pile head joint structure of the present invention.

FIG. 4 is a vertical sectional view showing an example of a conventional pile head joint structure.

FIG. 5 is a vertical sectional view showing an example of a conventional pile head joint structure.

FIG. 6 is a vertical sectional view showing an example of a conventional pile head joint structure.

[Explanation of symbols]

1 steel pipe pile 2 footing concrete 3 pile head hardware 4 Cylindrical lid 5 convex pieces 6 hook-shaped slit 7 Anchored rebar 8 Insulation cushioning material 9 Discarded concrete 10 Lock 11 Filled concrete 12 Filling reinforcement steel 13 pile head reinforcement 14 Steel pipe pile top lid

Claims (2)

[Claims] 1. A pile head of a steel pipe pile that is cast in the ground and has a plurality of convex pieces near the upper end, has an inner diameter larger than the outer diameter of the pile head, and has an upper end closed and a peripheral surface. A cylindrical lid having a plurality of hook-shaped slits at its lower end, and a pile head metal member composed of a fixing rebar integrated with the lid so as to cover the convex piece and the hook-shaped slit. Pile head joint structure for steel pipe piles. 2. The pile head joint structure according to claim 1, wherein an insulating cushioning material is interposed between the inside of the lid and the outside of the steel pipe pile.