JPS59134228A - Integration work of pile or continuous wall and footing - Google Patents

Abstract

PURPOSE:To prevent the reduction of prestress by a method in which the end of a steel material is projected from a footing, the steel material is tensed by using a fixing tool to introduce prestress force into the steel material, and a pile or continuous wall and the footing are integrated. CONSTITUTION:A PC pile 14 in which plural PC steel materials 10 are buried in a tense state in concrete is driven into the ground 16, the upper end 26 of the PC pile 14 is cut off so slightly project the pile head 18 to the ground surface, and the steel material 10 is left as an upper end exposure 28 without being cut off. Concrete is placed to form a footing 24, and the upper end of the steel material 10 is slightly projected upwards by forming a recessed fixing portion 30 on the upper end of the footing 24. A fixing tool 32 is inserted into the fixing portion 30, the steel material 10 is tensed to introduce prestress force between the pile head 18 and the footing 24, and thereby the PC pile 14 and the footing 24 are integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an integrated construction method of piles or continuous walls and footings, and more specifically, prestressing concrete (PC) in which steel materials for concrete (hereinafter abbreviated as PC) are embedded. stake,
This relates to a construction method that integrates cast-in-place piles or underground continuous walls with footings formed during concrete pouring.

Conventionally, for example, in the construction method of integrating the so-called P'C pile and footing, in which prestressing steel was buried in concrete under tension and a bracing stress was introduced into the concrete pile, The upper end of the pile was cut off along with the PC steel material, and the pile head was slightly exposed above the ground before being joined to the footing.

However, if you cut off the top end of the pile like this,
There was a problem in that the prestress at the pile head decreased and the area near the joint with the footch did not become a PC pile.

For this reason, a method of reinforcing a portion where prestress has decreased, as shown in FIG. 1 or 2, has been proposed.

However, in the construction method shown in Fig. 1, a PC pile 14 made of PC steel 10 and concrete 12 is driven into the ground 16 to a predetermined depth, and the pile head 18 is cut off to a point where it slightly protrudes above the ground. After that, a hole 20 of a predetermined depth is excavated around the outer periphery of the PC pile 14, and a part of the reinforcing reinforcing bar 22 is inserted into this hole 20, and the pile is built, and the hole 20 and the concrete filling part are After pouring concrete 21, the footing 24 is finished with concrete and integrated.

In addition, in the construction method shown in FIG. 2, the steps from driving the PC pile 14 to cutting off the pile head 18 are similar to the construction method described above. After constructing the building with reinforcing reinforcing bars 22 partially inserted, and pouring concrete for the middle 3rd concrete section 21,
The footing 24 is finished with concrete and integrated.

However, even with this construction method, although the joint state between the PC pile and the footing 24 is reinforced to some extent, it does not recover the reduced prestress at the pile head 18, and the fundamental problem cannot be solved. The problem was that it had not been done.

In addition, as described above, there are holes 2 on the outer periphery and inside of the PC pile 14.
Excavation of 0 and installation of reinforcing reinforcing bars 22 have the drawbacks of being an obstacle to shortening the construction period and increasing costs.

This invention focuses on the drawbacks of the conventional method as described above,
It was developed to solve this problem, and its purpose is to have an economical advantage in that it can be constructed without adding reinforcement members or excavation work, and to cut the head of the PC pile from 1 to 1 To provide a construction method for integrating a column or a continuous wall and a footing, which can recover the decrease in prestress even when the prestress is turned off, and can strengthen the joint state between the footing and the PC pile or underground continuous wall.

In order to achieve the above object, the present invention uses a construction method that integrates a wall or a continuous wall with a footing, in which a footing is formed by pouring concrete into the exposed upper end of a steel material for prestressed concrete, and the end of the preparation is removed from the footing. The footing is characterized in that the footing is slightly protruded, and a fixing tool is used to tension the M-wall and introduce a prestress force, thereby integrating the pile or the continuous wall and the footing.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

In the following description, parts that are the same as or correspond to the conventional construction method described above are given the same reference numerals.

FIGS. 3 to 6 show an embodiment of the method of integrating a pile or a continuous wall and a footing according to the present invention.

The integrated construction method shown in the figure shows the case where a PC pile and a footing are integrated. First, a PC pile, in which a plurality of PC steel materials 10 are buried under tension in concrete 12, is placed in a predetermined position. Drive it into the ground 16 to a depth, cut off the upper end 26 of the PC pile 14 exposed above the ground,
The state in which the counter head 18 is slightly protruded above the ground is similar to the conventional construction method (see FIGS. 3 and 4).

The method of integrating footings and piles shown in the figure has the following features compared to the conventional method described above.

That is, when cutting off the upper end part 26 of the PC pile 14, the PC steel material 10 is not cut, but is left as it is as the upper end exposed part 28 as shown in FIG. 4, and concrete is poured into this part. At the same time, the upper end of the PC steel material 10 is made to protrude slightly upward by forming a concave fixing part 30 at the upper end of the footing 24 (see Fig. 5). )
.

In this case, it is preferable to bury the PC steel material 10 in advance in the concrete 12 with a screw that matches the fixing tool 32, which will be described later, installed at the upper end of the steel material 10 to facilitate the fixing work. By the way.

Also, the thickness of the footing 24 to be formed in advance, PC
Cl2O burial length in the ground 16 and protruding pile head 1
8 length, etc., and add a predetermined length of P to the upper end of PCCl2O.
Construction J with the upper end exposed portion 28 of the steel material 10 for C formed
It is also possible to do this, and by doing so, the above-mentioned cut-off operation is not required, which is also economically advantageous.

After that, by inserting the fixing tool 32 into the fixing part 30 and tensioning the PC steel material 10, a pre-stress hole is introduced between the pile head 18 and the footing 24, thereby forming the PCCl2O footing. 24 (see Figure 6).

In introducing tension to this PC steel material 10,
It is also possible to carry out this process before the poured concrete of the footing 24 is completely solidified, or if necessary, cover the exposed upper end portion 28 with a sheath made of steel pipe or the like and carry out this process after the poured concrete has assimilated. It is also possible.

Now, with the above configuration, the footing 24 and PCCl2
In the O integration method, the pile head 18 is cut off by cutting off the PCCl2O upper end 26 as in the conventional method described above.
Even if the prestress decreases, the prestress is recovered by tensioning the PC steel material 10 again, and
Since the joints of the PCCl2O footings 24 are also joined with prestress introduced, the joints are much stronger than the conventional reinforcing bars 22, and the problems associated with cut-off can be fundamentally solved. can.

In addition, the configuration for achieving the above-mentioned effects is relatively simple, such as forming the fixing part 30 and adding the fixing tool 32, and has economical advantages such as shortening the construction period and reducing rice production. It also has the characteristics of

FIG. 7 shows a second embodiment of the present invention, and to explain only its features, the first embodiment described above replaces 1° of PC&lil material buried in advance with PCCl2.
The upper end portion 26 is cut off to form the upper end exposed portion 28, whereas in this embodiment, the upper end portion 26 is cut off.
A relatively short steel material 33 for a connecting PC, one end of which is buried as a dead anchor 36, is placed in the outer periphery of the board so that the other end becomes the exposed portion 28.

A PC shaft with such a configuration is installed underground 16, and its pile head 18
The above-mentioned effects can be achieved by lowering the steel material 33 to a slightly exposed state, forming the upper footing 24, and applying prestress to the connecting PC steel material 33 by tensioning it using the fixing tool 32. .

FIG. 8 shows a third embodiment of the invention,
To explain only its characteristic points, while the above-mentioned 1st, 1st and 2nd embodiments all used piles driven into the existing PCCl2O underground 16, this embodiment uses piles vertically at the construction site. This is applied to a so-called cast-in-place shaft 34 which is formed by excavating a hole and pouring concrete into the vertical hole.

As shown in the figure, in this embodiment, the above 1) C
The steel material 10 is placed in advance so as to protrude from the pile head 18, and is formed into the upper end exposed portion 28, and the footing portion 24 and the footing portion 24 are otherwise formed in the same process as in the first embodiment. will be integrated.

Further, FIG. 9 shows a fourth embodiment of the present invention.

The integrated construction method shown in the figure consists of a footing and an underground continuous wall 35.
This is applied to the case where the underground continuous wall 35
This is similar to the state in which the lower end of the PC steel material 10 that has been buried in advance is buried as a dead anchor 36.

It goes without saying that even in the case where the lower end of the steel material 10 for PC is made into the dead anchor 36 in advance, the effects described in the above-mentioned embodiments can be exhibited.

As described above, this invention provides a method for integrating PC piles with one cast-in-place pile or with an underground continuous wall and footing.
A footing is formed by pouring concrete onto the exposed upper end of the C steel material, and a fixing part is formed by slightly protruding the end of the PC steel material from the upper end of the footing, and a fixing tool is used within this fixing part. The steel material for the PC is tensed and prestress is introduced, and the PC, cast-in-place pile, or continuous underground wall or footing is integrated with the footing, and the prestress due to the cut-on of the PC pile is reduced. It is possible to recover these and to strengthen the joint between them and the footing.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are cross-sectional views showing a prestressed concrete pile and a footing formed by a conventional method. Figures 3 to 6 are cross-sectional views of each process showing an embodiment of the method of integrating prestressed concrete piles and footings according to the present invention.
This is done in the order shown. FIG. 7 shows a second embodiment of the present invention.
Figure a) is a cross-sectional view, and figure (b) is a top view of the pile. FIG. 8 is a sectional view showing a third embodiment in which the present invention is applied to the integration of a cast-in-place pile and a footing. FIG. 9 is a sectional view showing a fourth embodiment in which the present invention is applied to the integration of a footing with an underground continuous wall. 10... Steel materials for PC 12.
・・・・・・・・・・・・・・・Concrete 14...
・・・・・・・・・・・・PC anti-16・・・・・・・・・
・・・・・・Underground 18・・・・・・・・・・・・・・・
・Pile head 20・・・・・・・・・・・・ Hole 22
・・・・・・・・・・・・Reinforcement reinforcing bar 24...
・・・・・・・・・・i・Footing 26・・・・・・
......Top end portion 28...
...Top exposed portion 30...
・Fixing part 32...Fixing tool 3
5・・・・・・・・・・・・Underground continuous wall 36...
・・・・・・・・・・・・Dead Anchor Patent Applicant Obayashi Co., Ltd. Representative Person
Patent Attorney - Kensuke Shiro No. 11F'1':;2 Figure 7 Figure 9

Claims (1)

[Scope of Claims] (1) In a construction method that integrates a prestressed concrete pile with embedded steel material for press i-rest concrete, a cast-in-place pile, or an underground continuous wall and a footing,
The footing is formed by pouring concrete onto the exposed upper end of the steel material for prestressed concrete, the end of the steel material is slightly protruded from the upper end of the footing to form a fixing section, and a fixing tool is used within the fixing section to form the footing. A combination of a pile or continuous wall and a footing, characterized in that the steel material is tensed and a prestressing force is introduced, and the footing is integrated with the prestressed concrete pile, cast-in-place pile, or anti-cough underground continuous wall. Integrated construction method. (2. The construction method according to claim 1, wherein the upper end exposed portion is formed by cutting off the upper end of the prestressed concrete 1 to pile. An integrated construction method with a footing. (3) In the construction method described in claim 1, a connecting press 1 whose lower part is buried near the upper end of an existing prestressed concrete pile to a steel material for rest are installed. A method of integrating a footing with a pile or a continuous wall in which the upper end is exposed. (4) In the construction method according to claim 1, the upper end of the prestressed concrete/steel material is A construction method for integrating a pile or a continuous wall with a footing, characterized in that the prestressed concrete pile, cast-in-place shaft, or continuous underground wall is arranged in a state that projects upward from the upper end thereof to form the upper end exposed part.