JP6186883B2 - Pile foundation structure and construction method of pile foundation structure - Google Patents

Description

  The present invention relates to a pile foundation structure and a method for constructing the pile foundation structure.

  In the construction of a structure (for example, a building), a pile foundation structure is known in which a pile is formed deep in the ground to support a building when the ground cannot support the building with a shallow foundation.

  Moreover, when rebuilding a building, an existing pile used for an old building may be reused as a pile of a new building without being removed (see, for example, Patent Document 1). In this case, there is also known a method for evaluating the soundness (the presence or absence of cracks, etc.) without digging up the pile and nondestructively (see, for example, Patent Document 2).

JP-A-8-109653 JP 2006-322734 A

  However, in the evaluation of soundness as described above, if an evaluation result is obtained that the pile is not healthy (there is a crack), the pile cannot be reused as a pile of a new building, and an alternative pile There was a problem that it had to be newly placed.

  This invention is made | formed in view of this conventional subject, The main objective is to recycle the existing pile regardless of soundness.

To achieve this object, the pile foundation structure of the present invention is
Piles buried in the ground,
A plurality of angle steels provided so as to surround the periphery of the pile;
A foundation formed by burying a pile head of the pile;
With
The plurality of angle steels each have a reinforcing portion that reinforces the pile and a fixing portion that is fixed to the foundation .
The pile is a concrete pile formed of reinforced concrete,
The pile head is a concrete pile head formed of reinforced concrete.
It is characterized by that.

In this pile foundation structure, it is desirable that a reinforcing bar protrudes from the pile head of the pile, and the reinforcing bar protruding from the pile head and the reinforcing bar arranged on the foundation are joined.
According to such a pile foundation structure, it is possible to improve the fixability between the pile and the foundation.

In addition, piles buried in the ground,
A plurality of angle steels provided so as to surround the periphery of the pile;
A foundation formed by burying a pile head of the pile;
With
The plurality of angle steels each have a reinforcing portion that reinforces the pile and a fixing portion that is fixed to the foundation.
The pile is hollow piles which have a middle empty section,
The pile head is a hollow pile head having a hollow portion .

In such a pile foundation structure, it is desirable that a fixing material for fixing the pile and the foundation is inserted into a hollow portion of the pile.
According to such a pile foundation structure, it is possible to improve the fixability between the pile and the foundation.

In such a pile foundation structure, it is desirable that the angle steel and the reinforcing bars arranged on the foundation are joined.
According to such a pile foundation structure, it is possible to further improve the fixing property between the angle steel and the foundation.

  Further, the pile foundation structure construction method of the present invention includes an angle steel press-fitting process in which a plurality of angle steels are press-fitted into the ground so as to surround a pile buried in the ground, and the pile head of the pile is buried And forming a foundation, wherein each of the plurality of angle steels has a reinforcing part for reinforcing the pile and a fixing part fixed to the foundation.

  According to the present invention, existing piles can be reused regardless of soundness.

It is explanatory drawing of the pile foundation structure which concerns on 1st Embodiment. It is a flowchart which shows the procedure of the construction method of the pile foundation structure which concerns on 1st Embodiment. It is a perspective view which shows the state which dug out the pile head 10A of the pile 10. FIG. 2 is a perspective view showing a state in which angle steel is press-fitted around a pile 10. FIG. It is a flowchart which shows the procedure of the construction method of the pile foundation structure which concerns on 2nd Embodiment. It is explanatory drawing of the pile foundation structure which concerns on 2nd Embodiment. It is explanatory drawing of the pile foundation structure which concerns on 3rd Embodiment. It is explanatory drawing of the pile foundation structure which concerns on 4th Embodiment.

=== First Embodiment ===
<About pile foundation structure>
FIG. 1 is an explanatory diagram of a pile foundation structure according to the first embodiment.

  As shown in FIG. 1, the pile foundation structure of the present embodiment includes a pile 10, an angle steel 20, and a foundation 30.

  The pile 10 is a pile (existing pile) used in an old building (not shown) and is reused as a pile of a new building. The part of the pile 10 on the side of the pile head 10A is embedded in the foundation 30 of the new building, and the part below (vertically in the vertical direction) is embedded in the ground. In addition, the pile 10 of this embodiment is a cast-in-place concrete pile (solid pile), and has a damage site | part (crack part) not shown.

  Angle steel (also referred to as angle steel) 20 is an iron member having an L-shaped cross section. The angle steel 20 of the present embodiment is an equilateral angle steel having the same length of each side of the L shape. Further, the length of the angle steel 20 in the ridge line direction is at least the length from the pile head 10 </ b> A of the pile 10 to the cracked portion. In the present embodiment, four angle steels 20 are provided so as to surround the periphery of the pile 10, and each angle steel 20 is disposed such that the inner surface faces the outer peripheral surface of the pile 10. . Each angle steel 20 has a portion (indicated by a broken line in the drawing) that is press-fitted into the ground and a portion embedded in the foundation 30 (indicated by a solid line in the drawing).

  The foundation 30 is a lower structure of the new building, and is provided to stably support the weight of the new building. The foundation 30 of this embodiment is formed of reinforced concrete.

<About the construction method of pile foundation structure>
FIG. 2 is a flowchart showing a procedure of a method for constructing a pile foundation structure according to the first embodiment. 3 is a perspective view showing a state in which the pile head 10A of the pile 10 is dug, and FIG. 4 is a perspective view showing a state in which the angle steel 20 is press-fitted around the pile 10.

  In the following, the description starts from the state where the old building (including the foundation) has been removed. By removing the old building, the pile 10 used in the building remains in a state of being buried in the ground.

  First, as shown in FIG. 3, the soil around the pile head 10 </ b> A of the pile 10 is removed, and the length L (about 50 cm in this embodiment) from the end of the pile head 10 </ b> A of the pile 10. The part is exposed (pile head digging step S101). At this time, the other part of the pile 10 remains buried in the ground.

  Next, as shown in FIG. 4, angle steel 20 is press-fitted around the pile 10 (underground) (angle steel press-fitting step S102). At this time, it is desirable that the upper end of the angle steel 20 is set at substantially the same position as the pile head 10A. This is to improve the fixing property between the angle steel 20 and the foundation 30. The lower end of the angle steel 20 is press-fitted so as to be positioned at least below the cracked portion of the pile 10. The soil between the angle steel 20 and the pile 10 may be left as it is or may be removed.

  In this embodiment, since the angle steel 20 is used as the reinforcing material of the pile 10, the press-fitting resistance when press-fitting into the ground is small (easily press-fitted) compared to the case of using other steel materials (for example, steel pipes). . Thereby, reinforcement of the pile 10 can be performed easily. Moreover, the resistance force (reinforcing effect) with respect to a shearing force can be improved by arrange | positioning the angle steel 20 around the pile 10 like a figure.

  After that, reinforcing bars and formwork are installed to form the foundation 30 of the new building, and concrete is placed in the formwork (foundation placement / concrete placing step S103). In this way, the foundation 30 for the new building is formed, and the pile 10 pile head 10A and the upper portion of the angle steel 20 (part indicated by a solid line in FIG. 1) are embedded in the foundation 30 (embedding fixing step S104).

  In this way, the pile foundation structure shown in FIG. 1 is constructed. The upper part (part indicated by a solid line) of each angle steel 20 is fixed to the foundation 30 by being embedded in the foundation 30. That is, the part constitutes a fixing unit. Moreover, the site | part (part shown with a broken line) below the part is reinforcing the pile 10 by arrange | positioning around the pile 10. FIG. That is, the said part comprises the reinforcement part. Thus, in the pile foundation structure of the present embodiment, the angle steel 20 has a fixing portion that is fixed to the foundation 30 and a reinforcing portion that reinforces the pile 10.

  As described above, the pile foundation structure of the present embodiment includes the pile 10 embedded in the ground, the four angle steels 20 provided to surround the pile 10, and the pile head 10 </ b> A of the pile 10. And a foundation 30 formed by burying the material. Each angle steel 20 has a reinforcing portion that is pressed into the ground and reinforces the pile 10, and a fixing portion that is embedded in the foundation 30 and fixed to the foundation 30.

  Thereby, even when the existing pile 10 has a crack part, the pile 10 can be reused as a pile of a new building. Moreover, in this embodiment, since the angle steel 20 is used, it is easy to press-fit into the ground (construction is easy). Moreover, the reinforcement effect with respect to a shear stress can be heightened.

  In addition, you may make it join the upper end of each angle steel 20 and the reinforcement (not shown) arranged on the foundation 30 by welding etc., for example. In this case, the fixability to the foundation 30 can be further improved. Further, for example, in the state of FIG. 4, adjacent angle steels 20 may be connected (joined) to each other.

=== Second Embodiment ===
In 2nd Embodiment, the process after exposing the pile head 10A of the pile 10 differs from 1st Embodiment.

  FIG. 5 is a flowchart showing a procedure of a method for constructing a pile foundation structure according to the second embodiment. In FIG. 5, the same steps as those in FIG.

  In the second embodiment, after the pile head 10A of the pile 10 is exposed (after the pile head digging step S101), the pile head processing is performed (pile head processing step S101 ′). A pile head process is a process which picks up the top part (head) of a pile. By this pile head processing, the reinforcing bars embedded in the pile 10 are exposed.

  FIG. 6 is an explanatory diagram of a pile foundation structure according to the second embodiment. In FIG. 6, the same components as those in FIG.

  In 2nd Embodiment, the reinforcing bar 11 is exposed about 20 cm at the edge of the pile head 10A of the pile 10 by performing the pile head process mentioned above. And in 2nd Embodiment, the reinforcing bar 11 exposed by the pile head process and the reinforcing bar (not shown) arranged on the foundation 30 are joined by welding, for example. Thereby, the fixability of the pile 10 and the foundation 30 can be improved more. Further, reinforcing bars (not shown) arranged on the foundation 30 and the upper ends of the angle steels 20 may be joined by welding or the like.

=== Third Embodiment ===
In 3rd Embodiment, the kind of pile used for a pile foundation structure differs from the above-mentioned embodiment. FIG. 7 is an explanatory diagram of a pile foundation structure according to the third embodiment. In FIG. 7, parts having the same configuration as in FIG.

In 3rd Embodiment, the pile 100 is used as an existing pile.
The pile 100 is a pile having a hollow portion (for example, a PC pile, a PHC pile, a steel pipe, etc.).

  In addition, the construction method of a pile foundation structure is substantially the same as 1st Embodiment (FIG. 2).

  Thus, in the third embodiment, by providing the angle steel 20 around the pile 100 as shown in FIG. 7 (press-fitting), the pile 100 can be re-used as a pile of a new building regardless of the soundness of the pile 100. Can be used.

=== Fourth Embodiment ===
In 4th Embodiment, the place which has inserted the fixing material in the hollow part of the pile 100 differs from 3rd Embodiment.

  FIG. 8 is an explanatory diagram of a pile foundation structure according to the fourth embodiment. In FIG. 8, parts having the same configuration as in FIG.

  As shown in FIG. 8, in the fourth embodiment, the reinforcing bar 200 is inserted into the hollow portion of the pile 100. Further, the upper end of the reinforcing bar 200 protrudes from the pile head 100 </ b> A of the pile 100. The hollow portion 100B into which the reinforcing bar 200 is inserted is filled with a filler (not shown) such as concrete.

  And the reinforcing bar of the reinforcing bar rod 200 (the reinforcing bar protruding from the pile head 100A of the pile 100) and the reinforcing bar arranged on the foundation 30 are joined together by welding or the like.

  In this case, the fixing property between the pile 100 and the foundation 30 can be further improved. Further, reinforcing bars (not shown) arranged on the foundation 30 and the upper ends of the angle steels 20 may be joined by welding or the like.

=== About Other Embodiments ===
The above embodiment is for facilitating the understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About pile>
In the above-described embodiment, the piles (pile 10 and pile 100) have cracked portions (unhealthy), but the present invention is not limited to this and may be sound. Also in this case, the angle steel 20 may be arranged around the pile to reinforce.

<About Angle Steel 20>
The angle steel 20 of the above-described embodiment uses the equilateral chevron steel having the same side length, but may use an unequal chevron steel having a different side length.

  In the above-described embodiment, four angle steels 20 are arranged around the piles (pile 10 and pile 100). However, the number of angle steels arranged around the pile is not limited to four, and a plurality of ( 2 or more). For example, in the case of two, the length of each side may be arranged (press-fitted) so as to surround the periphery of the pile using angle steel about twice as long as the angle steel 20.

10 piles (solid piles)
10A Pile head 11 Reinforcement 20 Angle steel 30 Foundation 100 Pile (hollow pile)
100A Pile head 100B Hollow part 200 Reinforcing bar

Claims (6)

Piles buried in the ground,
A plurality of angle steels provided so as to surround the periphery of the pile;
A foundation formed by burying a pile head of the pile;
With
The plurality of angle steels each have a reinforcing portion that reinforces the pile and a fixing portion that is fixed to the foundation .
The pile is a concrete pile formed of reinforced concrete,
The pile head is a concrete pile head formed of reinforced concrete.
Pile foundation structure characterized by that. The pile foundation structure according to claim 1 ,
Reinforcing bars protrude from the pile head of the pile,
The rebar protruding from the pile head and the rebar arranged on the foundation are joined,
Pile foundation structure characterized by that. Piles buried in the ground,
A plurality of angle steels provided so as to surround the periphery of the pile;
A foundation formed by burying a pile head of the pile;
With
The plurality of angle steels each have a reinforcing portion that reinforces the pile and a fixing portion that is fixed to the foundation.
The pile is hollow piles which have a middle empty section,
The pile head is a hollow pile head having a hollow portion,
Pile foundation structure characterized by that. The pile foundation structure according to claim 3 ,
A fixing material for fixing the pile and the foundation is inserted in the hollow portion of the pile,
Pile foundation structure characterized by that. A pile foundation structure according to any one of claims 1 to 4 ,
The angle steel and the reinforcing bars arranged on the foundation are joined,
Pile foundation structure characterized by that. An angle steel press-fitting process in which a plurality of angle steels are press-fitted into the ground so as to surround a pile buried in the ground,
A foundation forming step of burying a pile head of the pile to form a foundation;
Have
The method of constructing a pile foundation structure, wherein each of the plurality of angle steels includes a reinforcing portion that reinforces the pile and a fixing portion that is fixed to the foundation.

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