JP2002138469A - Pile head joint structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile head joint structure capable of preventing the crushing of a footing pile or an upper structure while decreasing rotational rigidity in a pile head and ensuring thereby the safety of the structure. SOLUTION: Steel plates 14 and 14 are provided to both of surfaces opposed to each other of the pile head 12a and the upper structure 13, a narrow diameter section 15 having a small plane diameter size compared with both of the pile head 12a and the steel plates 14 and 14 is provided between the pile head 12a and the upper structure 13 in a state to come into contact with the steel plates 14 and 14, and reinforcing bars 16 arranged so as to reach the upper structure 13 from the pile head 12a by passing through the inside of the narrow diameter section 15 are inserted into holes 17 bored in the steel plates 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pile head joining structure for joining a pile head of a foundation pile installed in the ground and an upper structure supported by the foundation pile.

[0002]

2. Description of the Related Art As is well known, a very large bending moment is generated at the joint between a pile head of a foundation pile and an upper structure due to the inertial force of the upper structure. Therefore, as shown in FIG. 5, the foundation pile 2 is located between the foundation pile 1 and the foundation beam 3 of the superstructure 2.
By providing the small-diameter column portion 4 having a smaller plane diameter than that of the first embodiment, the rotational rigidity at the pile head is reduced, and when a horizontal force is applied, the bending generated at the pile head 1a of the foundation pile 1, the foundation beam 3, and the like. A pile head joint structure 5 that reduces the moment has been proposed (for example, refer to JP-A-2000-104336).

[0003]

In the pile head joint structure 5, when a horizontal force acts, the pile head 1a rotates as shown in FIG. 6 or FIG. A gap S is formed between the diameter column portion 4 or the pile head 1a and the small diameter column portion 4, and the load of the upper structure 2 is reduced by the outer peripheral edge portion 4a of the small diameter column portion 4 and the foundation beam 3 or the pile head 1a. Between the base beam 3 and a part of the pile head 1a in contact with the outer peripheral edge 4a of the small-diameter column 4 (indicated by a symbol P in FIG. 8). There is a problem that the concrete shown in (shown) is easily crushed.

[0004] In particular, even in a level 1 earthquake which is expected to occur several times during the life of the building, the pile head joint structure 5 is required.
Is expected to be in a state as shown in FIGS. 6 and 7, and it may be difficult to ensure the safety during the life of the building. Further, in the pile head joint structure 5, when the concrete crushing of the portion P in FIG. 8 progresses, the upper structure 2 is supported in an area that can safely support the upper structure 2 even in a normal state. May not be possible.

[0005] The present invention has been made in view of such circumstances, and prevents the collapse of a foundation pile or an upper structure while reducing the rotational rigidity at the pile head, thereby ensuring the safety of the structure. It is an object of the present invention to provide a pile head joint structure that can be used.

[0006]

Means for Solving the Problems To solve the above problems, the present invention employs the following means. The invention according to claim 1 is a pile head joint structure for joining a pile head of a foundation pile installed in the ground and an upper structure supported by the foundation pile, wherein the pile head and the upper structure On one or both of the opposing surfaces, a steel plate is installed, between the pile head and the superstructure, in contact with the steel plate, compared to both the pile head and the steel plate. A small diameter portion having a small plane diameter is provided, and a structural material penetrating through the small diameter portion and arranged from the pile head to the upper structure is inserted into a hole provided in the steel plate. Features.

[0007] With such a configuration, when the pile head is rotationally deformed, the foundation pile or the upper structure is in contact with the outer peripheral edge of the narrow diameter portion where the stress is supposed to concentrate most, via the steel plate. Therefore, the stress concentrated in this portion can be dispersed by the steel plate.

A second aspect of the present invention is the invention according to the first aspect, wherein the small-diameter portion has a column structure in which a steel pipe is filled with concrete.

The invention described in claim 3 is the first or second invention.
In the invention described in the above, a plurality of the holes are provided.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1: is a figure which shows one Embodiment of this invention, and the code | symbol 11 in a figure shows the pile head joint structure. The pile head joint structure 11 joins a pile head 12a of a foundation pile 12 installed in the ground and an upper structure 13 supported by the foundation pile 12, and a pair of steel plates 1
4, 14; a small-diameter portion 15 located between the steel plates 14, 14; and a reinforcing bar (a structural material) penetrating through the small-diameter portion 15 and extending from the pile head 12a to the upper structure 13. )
16 schematically.

As shown in FIG. 2, the steel plate 14 is provided with a hole 17 at the center thereof, and as shown in FIG. It is arranged on both sides and is configured to contact the small diameter portion 15 from above and below. The lower steel plate 14 and the pile head 12
Between them, a smoothing mortar M is provided.

The small-diameter portion 15 has a steel pipe 18 as shown in FIG.
It is formed by filling concrete C (see FIG. 1) therein, and is configured as a column structure 19 whose height dimension is smaller than the diameter dimension. The steel pipe 18 constituting the column structure 19 has a smaller plane diameter than the pile diameter of both the pile head 12a and the steel plate 14 of the foundation pile 12.

The pile head joint structure 11 having such a structure is deformed as shown in FIG. 3 when, for example, the pile head 12a is rotated and deformed during an earthquake or the like. The upper structure 13 (or the foundation pile 12) comes into contact with the outer peripheral edge 15a of the small-diameter portion 15 where it is supposed to concentrate by the steel plate 14. Therefore, the stress concentrated in this portion can be dispersed by the steel plate 14 and transmitted to the upper structure 13 (or the foundation pile 12), and local collapse of the foundation pile 12 and the upper structure 13 can be prevented. . Accordingly, safety can be ensured even when a large-scale earthquake occurs several times during the life of the building, and by preventing local crushing of concrete, even in normal times, the pile head joint structure 11 can be secured. In this case, the area that can be supported between the upper structure 13 and the foundation pile 12 is not reduced, and safety in this case can be ensured.

In the above embodiment, the steel plate 14
Is not limited to the structure shown in FIG.
Like a steel plate 14 'shown in FIG. 4, a plurality of holes 21, 21,... For inserting a reinforcing bar (structural material) may be provided at the center thereof. Thus, the area of the hole 21 can be minimized in accordance with the dimensions of the reinforcing bar 16, and the processing cost can be reduced.

In the above embodiment, the small-diameter portion 15 has a structure in which the steel pipe 18 is filled with concrete C in order to secure the vertical strength, but the present invention is not limited to this. The part 15 may have a reinforced concrete structure. Furthermore, the steel plate 18 does not need to be installed on both opposing surfaces of the foundation pile 12 and the upper structure 13, and may be installed only on one side thereof.

[0016]

As described above, according to the first aspect of the present invention, the stress concentrated on the small diameter portion can be transmitted to the foundation pile and the upper structure by dispersing the stress by the steel plate. Local collapse of the structure can be prevented. As a result, safety can be ensured even in the event of a large-scale earthquake, and normal-time safety of the applicable structure can be ensured.

According to the second aspect of the present invention, since the small-diameter portion has a configuration in which the steel pipe is filled with concrete, the supporting strength of the steel pipe can be ensured.

According to the third aspect of the present invention, since a plurality of holes are formed in the steel plate, the area of the holes can be minimized in accordance with the dimensions of the structural material. Cost can be reduced.

[Brief description of the drawings]

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

FIG. 2 is an exploded perspective view of a steel plate and a steel pipe constituting the pile head joint structure.

FIG. 3 is an elevational sectional view showing a deformed state of the pile head joint structure shown in FIG. 1 during an earthquake.

FIG. 4 is a perspective view of a steel plate schematically showing another embodiment of the present invention.

FIG. 5 is an elevational sectional view of a pile head joint structure schematically showing a conventional technique of the present invention.

6 is an elevational sectional view showing a deformed state of the pile head joint structure shown in FIG. 5 during an earthquake.

FIG. 7 is an elevational sectional view showing another deformation state of the pile head joint structure shown in FIG. 5 during an earthquake.

FIG. 8 is an elevational sectional view schematically showing a portion where concrete crush easily occurs in the pile head joint structure shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Pile head connection structure 12 Foundation pile 12a Pile head 13 Superstructure 14, 14 'Steel plate 15 Small diameter part 16 Reinforcement 17, 21 Hole 18 Steel pipe 19 Column structure

Claims (3)

[Claims] 1. A pile head joining structure for joining a pile head of a foundation pile installed in the ground and an upper structure supported by the foundation pile, wherein the pile head and the upper structure face each other. A steel plate is installed on one or both of the surfaces, and between the pile head and the superstructure, in a state of contact with the steel plate, a plane diameter dimension compared with both the pile head and the steel plate A small diameter portion is provided, and a structural material disposed so as to penetrate through the small diameter portion and reach from the pile head to the upper structure is inserted into a hole provided in the steel plate. Pile head joint structure. 2. The small-diameter portion has a columnar structure in which a steel pipe is filled with concrete.
Pile head joint structure described in 4. 3. The pile head joint structure according to claim 1, wherein a plurality of said holes are provided.