JP2007046304A - Structure of pile foundation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a pile foundation, which facilitates the handling of a partition plate during construction, and which hardly causes the horizontal relative displacement of the partition plate with respect to an upper end of a pile, even in the action of a horizontal external force. <P>SOLUTION: In this structure of the pile foundation, a cylindrical pile 1 is buried in ground, and the pile cap 3 is installed at the upper end of the pile via the partition plate 2. Almost the whole surface of the upper end of the pile is covered with the partition plate, and a reinforcing rib 4 for being fitted into the pile is integrally provided on the undersurface side of the partition plate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pile foundation structure in which a cylindrical pile is buried in the ground, and a pile cap is installed on the upper end portion of the pile via a partition plate.

The above pile foundation structure structurally insulates the pile cap and the pile when a horizontal external force such as seismic force is applied while allowing the vertical load from the pile cap side to be transmitted to the cylindrical pile. And the pile cap is installed in the upper end part of the pile through the partition plate so that the maximum bending moment, shearing force, etc. which act on the pile can be made small.
In the conventional pile foundation structure, a partition plate having a substantially constant thickness is placed so as to cover the entire upper end of the pile over the entire surface, and pile cap concrete is placed on the upper surface of the partition plate. Yes (see, for example, Patent Document 1).

JP-A-61-225425

In the pile foundation structure, even when a large vertical load is applied, the partition plate portion facing the hollow portion of the pile is not deformed, and the reaction force is distributed over substantially the entire surface of the partition plate. It is necessary to provide a partition plate with high bending rigidity so as to act on the pile cap.
For this reason, in the conventional pile foundation structure, it is necessary to use a partition plate that is thick and heavy so that the bending rigidity of the partition plate is increased, which complicates handling of the partition plate during construction. There are drawbacks.
In addition, since the partition plate is sandwiched between the pile cap and the upper end portion of the pile, when a horizontal external force is applied, the relative position of the partition plate in the horizontal direction with respect to the upper end portion of the pile is easily shifted, and the vertical There is also a possibility that the load cannot be transmitted efficiently.
The present invention has been made in view of the above circumstances, and it is easy to handle the partition plate at the time of construction, and the horizontal position of the partition plate relative to the upper end of the pile even when a horizontal external force is applied. The purpose is to provide a pile foundation structure that does not slip easily.

  A first characteristic configuration of the present invention is a pile foundation structure in which a cylindrical pile is embedded in the ground, and a pile cap is installed on the upper end portion of the pile via a partition plate, and the partition plate The upper end of the pile is covered over substantially the entire surface, and a reinforcing rib that fits inside the pile is integrally provided on the lower surface side of the partition plate.

[Action and effect]
Reinforcing ribs are integrally provided on the lower surface side of the partition plate covering the upper end of the pile over almost the entire surface, and the reinforcing ribs are fitted inside the pile, so the partition plate is particularly thick. The bending rigidity of the pile can be increased efficiently with the reinforcing ribs, and the installation position of the partition plate with respect to the upper end of the pile is difficult to shift during construction. The relative position in the horizontal direction between the upper end and the partition plate is difficult to shift.
Therefore, the partition plate with high bending rigidity can be reduced in weight compared to the conventional one, and the installation position of the partition plate with respect to the upper end of the pile is less likely to shift during construction, making it easier to handle the partition plate during construction. In addition, even when an external force in the horizontal direction is applied, the relative position in the horizontal direction of the partition plate with respect to the upper end portion of the pile is difficult to shift.

  The second characteristic configuration of the present invention is that the reinforcing rib is formed of a strip material, and a plurality of the strip plates are arranged and integrated in a direction crossing each other.

[Action and effect]
Since the reinforcing rib is made of a band plate material, and a plurality of the band plate materials are arranged in an intersecting direction and integrated with each other, the bending rigidity can be easily increased over the entire partition plate. Falling deformation can also be prevented.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 shows a pile foundation structure according to the present invention, in which a cylindrical PC pile 1 centrifugally molded with concrete is embedded in the ground substantially vertically, and a steel partition plate 2 is provided at the upper end of the pile 1. A concrete pile cap 3 is installed therethrough.

  As shown in FIG. 2, the partition plate 2 is formed in a circular shape having substantially the same outer diameter as that of the pile 1 and covers the upper end portion of the pile 1 over substantially the entire surface. A plurality of configured reinforcing ribs 4 are integrally provided by welding.

  Each of the reinforcing ribs 4 is arranged in a direction intersecting each other and integrated, and is fitted into the inner hollow portion 10 of the pile 1. In this embodiment, the reinforcing ribs 4 are provided along the diameter direction of the partition plate 2. On both sides of the strip plate material 4a, strip plate materials 4b extending in the radial direction of the partition plate 2 are provided and integrated into a substantially cross shape by welding.

  And as shown in FIG. 1 (a), the pile head 5 of the pile 1 which has been laid in advance is exposed, and the filling 9 such as cement milk filled in the hollow portion 10 of the pile head 5 is partially The pile top surface 6 is cleaned and the partition plate 2 is placed on the pile head 5 as shown in FIG. 10, the pile cap concrete is placed, and the pile cap 3 is installed as shown in FIG. 1 (c), and the pile head 5 enters the pile cap 3 side. In addition, a gap 7 is provided in an annular shape between the outer peripheral side of the pile head 5 and the pile cap 3.

In this embodiment, a non-strength member such as foamed resin may be provided between the outer peripheral side of the pile head 5 and the pile cap 3 instead of the gap 7. The pile cap 3 may be inserted at a depth of about 1 outside diameter.
Moreover, you may make the pile head 5 enter the pile cap 3 side so that a clearance gap may not be formed between the pile caps 3.

[Second Embodiment]
FIG. 3 shows another embodiment of the pile foundation structure according to the present invention, and the pile head 5 is provided so as not to enter the pile cap 3 side. Cap 3 is easy to install.
Other configurations are the same as those of the first embodiment.

[Third Embodiment]
FIG. 4 shows another embodiment of the partition plate 2 provided in the pile foundation structure according to the present invention, and a plurality of reinforcing ribs 4 are arranged in a grid pattern in the direction crossing each other on the lower surface side of the partition plate 2 and integrated.
Other configurations are the same as those of the first embodiment.

[Fourth Embodiment]
FIG. 5 shows another embodiment of the partition plate 2 provided in the pile foundation structure according to the present invention, and a plurality of reinforcing ribs 4 are arranged in a substantially triangular annular shape on the lower surface side of the partition plate 2 and integrated.
Other configurations are the same as those of the first embodiment.

[Fifth Embodiment]
FIG. 6 shows another embodiment of the partition plate 2 provided in the pile foundation structure according to the present invention, in which a recess 11 is formed on the lower surface side of the partition plate 2 whose upper surface side is flat by casting, cutting, etc. Reinforcing ribs 4 that fit into the portion 10 are integrally provided.
Other configurations are the same as those of the first embodiment.

[Sixth Embodiment]
FIG. 7 shows another embodiment of the partition plate 2 provided in the pile foundation structure according to the present invention, in which a plurality of reinforcing ribs 4 are arranged substantially in parallel with each other on the lower surface side of the partition plate 2.
Other configurations are the same as those of the first embodiment.

[Other Embodiments]
1. The pile foundation structure by this invention may install the pile cap through the partition plate in the upper end part of the steel pipe pile.
2. In the pile foundation structure according to the present invention, a single reinforcing rib that fits inside the pile may be provided integrally on the lower surface side of the partition plate.
3. The pile foundation structure by this invention may provide the partition plate larger diameter than the outer diameter of a pile in the state in which an outer peripheral part protrudes from a pile.

Longitudinal section showing the construction procedure of pile foundation structure Side view (b) and bottom view (b) of partition plate Longitudinal sectional view showing the second embodiment Side view (b) and bottom view (b) showing the partition plate of the third embodiment Side view (b) and bottom view (b) showing the partition plate of the fourth embodiment Longitudinal sectional view (b) and bottom view (b) showing the partition plate of the fifth embodiment Longitudinal sectional view (b) and bottom view (b) showing the partition plate of the sixth embodiment

Explanation of symbols

1 Pile 2 Partition plate 3 Pile cap 4 Reinforcement rib

Claims (2)

A pile foundation structure in which a cylindrical pile is buried in the ground, and a pile cap is installed on the upper end of the pile via a partition plate,
The pile foundation structure which covered the upper end part of the said pile over the substantially whole surface with the said partition plate, and provided integrally the reinforcement rib fitted inside the said pile on the lower surface side of the said partition plate.   The pile foundation structure according to claim 1, wherein the reinforcing rib is formed of a band plate material, and a plurality of the band plate materials are arranged and integrated in a direction crossing each other.

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