JPH08109653A - Reuse of cast-in-place concrete pile - Google Patents

Abstract

PURPOSE: To reduce the construction cost by drilling a through hole into an existing caste-in-place concrete pile and excavating the ground under the pile and inserting a removable anchor into the hole and fixing the anchor with the ground and using once again a pile, whose bearing force is confirmed, as a foundation. CONSTITUTION: An existing building 2, which uses existing cast-in-place-concrete piles 1 as a foundation is demolished, thereby exposing the upper ends 1a of the piles 1. Then, through holes 3 are drilled by core boring in the longitudinal direction at the central part of the piles and the ground is further excavated under the pile, thereby forming a hole 4. Then, a removable type anchor 5 is inserted into the trough hole 3 and the hole 4 so that it may be fixed in the ground. Anchor reinforcing bars 6 are tensioned and load-applied to a design value, thereby confirming the bearing force of the piles 1. The piles 1 if its bearing force is confirmed, are used as a pile foundation as it is. If the piles 1 lack a specified bearing force, an additional pile is increased so as to make up for the insufficiency of the bearing force. After new piles 7 have been developed, a building 8 is to be constructed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reusing existing cast-in-place concrete piles.
The present invention relates to a method of reusing an existing cast-in-place concrete pile as it is or by reinforcing it without dismantling it.

[0002]

2. Description of the Related Art Recently, the cast-in-place concrete pile method is
Although it is rapidly becoming widespread, in general, reconstruction of buildings with cast-in-place pile foundations is still small in relation to the time of introduction, but in the case of piles before that, such as pedestal piles, etc. The method of piercing the pile and pulling out the pile is adopted. For cast-in-place piles, a similar method may be used when the pile diameter is small and the pile length is short.
However, in general, existing cast-in-place piles are often avoided and new construction is performed.

[0003]

The cast-in-place pile construction method, which was introduced into Japan in the 1940s, spread rapidly in the 1950s, and the building foundations supported by piles in urban areas are vulnerable to noise and vibration. There are many problems, and there are a lot of things by this construction method. On the other hand, considering the service life, it is necessary to dismantle the cast-in-place piles in the next 10 years as the buildings are rebuilt. However, if the existing cast-in-place concrete pile has a large diameter, it is very difficult to pull out or dismantle the pile. Therefore, when rebuilding a building, it is desirable to proactively reuse the existing piles without dismantling them and confirming their bearing capacity.

The present invention has been made in view of the above-mentioned present situation regarding the reuse of an existing cast-in-place concrete pile accompanying the rebuilding of a building, and the purpose thereof is to rebuild the existing cast-in-place concrete pile of the building. It is to provide a method of confirming the bearing capacity of an existing pile and reusing it without dismantling and newly constructing a pile.

[0005]

As a result of earnest studies on the solution of the above-mentioned problems, the present inventor inserts a removable anchor into an existing cast-in-place concrete pile and confirms the bearing capacity of the pile. I focused on.

The present invention is based on the above idea, and as a concrete means for achieving the object, a method of reusing an existing cast-in-place concrete pile, in which the length of the pile at the center is Direction through holes and drilling down to the ground below the pile, inserting a removable anchor into the through hole and fixing in the ground below the pile, and designing by tensioning the anchor muscles This is a method of using existing cast-in-place concrete piles, which is characterized by the steps of loading up to the load and confirming the bearing capacity of the piles, and using the piles with confirmed bearing capacity as the pile foundation of the building. .

The method of using the existing cast-in-place concrete pile according to the present invention is to reuse the existing cast-in-place pile, which was the pile foundation of the building, when reconstructing the building without dismantling it. is there. However, the pile must have the bearing capacity to withstand as a foundation for a new building. Therefore, in the present invention, the bearing capacity of an existing cast-in-place pile is measured to confirm whether or not it can withstand reuse. And for those that lack support capacity or are displaced as the foundation position due to the relationship with the new building,
New piles will be created and reinforced, and eccentricity will be covered to reuse.

As a method for confirming the bearing capacity of an existing cast-in-place concrete pile in the present invention, the following method is adopted. First, the existing building is dismantled and the upper end of the existing cast-in-place concrete pile used as the foundation is exposed. Then, a through hole is bored by core boring in the longitudinal direction of the central portion of the pile, and the ground below the pile is drilled. Next, a removable anchor is inserted into this through hole and fixed in the ground under the pile, and the anchor muscle is tensioned and loaded up to the design load to confirm the bearing capacity of the pile. Then, the pile whose bearing capacity has been confirmed is used as the pile foundation of the building.

In the above-mentioned confirmation of the bearing capacity of the pile, the pile whose bearing capacity has been confirmed is used as it is as the pile foundation of the building. A pile foundation will be reinforced by constructing additional piles. Then, the pile that is displaced as the foundation position due to the relationship with the new building is reused by a method such as covering the eccentricity of the axial force by footing.

[0010]

Operation When the existing cast-in-place concrete pile has a large diameter, it is very difficult to pull out or dismantle the pile, but according to the present invention, it is dismantled and rebuilt when the building is rebuilt. There is no need to construct piles in the pile, and the bearing capacity of existing piles can be confirmed and reused. Further, it is possible to avoid problems such as vibration, noise, and generation of waste materials.

[0011]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a process diagram showing an outline of a method of using an existing cast-in-place concrete pile according to the present invention. That is, the existing building 2 based on the existing cast-in-place concrete pile 1 is dismantled in the next process, and the upper end 1a of the existing cast-in-place concrete pile 1 is exposed.

Then, a through hole 3 is bored by core boring in the lengthwise direction of the central portion of the pile, and a hole 4 is formed by drilling to the ground below the pile. And if necessary,
At the time of forming the holes, the presence of cracks in the concrete of the cored pile is inspected by observation or the neutralization state is inspected by using phenolphthalein liquid or the like. If you want to check the strength of the concrete itself, perform a strength test such as a uniaxial compression test.

Next, the removable anchor 5 is inserted into this through hole and fixed in the ground under the pile. Furthermore, the anchor muscle 6
Check the bearing capacity of the pile by tensioning and loading up to the design load. Then, the piles 1 and 1 for which the bearing capacity is confirmed are used as they are as pile foundations for the building, and for the piles with insufficient bearing capacity, the piles 7 and 7 are newly created as pile foundations to increase Rebuild building 8.

[0014]

Industrial Applicability According to the present invention, a through hole in the longitudinal direction is formed in the center of an existing cast-in-place concrete pile, and the ground below the pile is drilled, and a removable anchor is inserted into the through hole. And fix it in the ground under the pile, and then tension the anchor bar to load it up to the design load, confirm the bearing capacity of the pile, and use the pile whose bearing capacity is confirmed as the pile foundation of the building. However, according to the present invention, it is not necessary to dismantle the existing cast-in-place concrete piles and to construct new piles when rebuilding the building. ,
Since it is possible to confirm the bearing capacity of the existing pile and reuse it, it is possible to contribute to cost reduction. (2) Compared to dismantling existing piles, there is less vibration and noise, and no waste material is generated, so this is a desirable and effective method from the viewpoint of environmental problems.

[Brief description of drawings]

FIG. 1 is a process diagram showing an outline of a method of using an existing cast-in-place concrete pile according to the present invention.

[Explanation of symbols]

 1 Existing cast-in-place concrete pile 1a Top of existing cast-in-place concrete pile 2 Existing building 3 Through hole 4 Hole drilled in the ground under the pile 5 Removable anchor 6 Anchor bar 7 Newly constructed cast-in-place concrete pile 8 Rebuilt building

Claims (3)

[Claims] 1. A method of reusing an existing cast-in-place concrete pile, comprising a step of forming a through hole in a longitudinal direction at a central portion of the pile and boring the ground below the pile. The process of inserting a removable anchor into the through-hole and fixing it in the ground under the pile, the process of tensioning the anchor bar to the design load and checking the bearing capacity of the pile, and the bearing capacity were confirmed. A method of using an existing cast-in-place concrete pile, characterized by using the pile as a pile foundation for a building. 2. A method of reusing an existing cast-in-place concrete pile, comprising a step of forming a through hole in the longitudinal direction at the center of the pile and drilling the ground below the pile, The process of inserting a removable anchor into the through-hole and fixing it in the ground under the pile, the process of tensioning the anchor bar to the design load and checking the bearing capacity of the pile, and the bearing capacity were confirmed. A method of using existing cast-in-place concrete piles, which uses piles as they are as pile foundations of a building, and for piles with insufficient bearing capacity, constructing new piles. 3. A method of reusing an existing cast-in-place concrete pile, comprising a step of forming a longitudinal through hole in the center of the pile and drilling the ground below the pile. The process of inserting a removable anchor into the through-hole and fixing it in the ground under the pile, the process of tensioning the anchor bar to the design load and checking the bearing capacity of the pile, and the bearing capacity were confirmed. On a stake,
A method of using existing cast-in-place concrete piles, which is characterized by installing footings for piles that are out of position.