JP6034348B2 - Prestressed steel pipe pile - Google Patents

Description

  The present invention relates to a prestressed steel pipe pile.

  Steel pipe piles are widely used for construction of bridge foundations, harbor / seaside structure foundations, building foundations, etc. in Japan, where there are many soft grounds, because they have high material strength and can be easily elongated. In particular, in recent years, steel pipe piles with a small diameter suitable for narrow conditions such as urban areas have been frequently used in pile foundation construction methods.

As a conventional technique, Patent Document 1 discloses a small-diameter steel pipe pile provided with a node having a predetermined dimensional relationship in an annular shape or a spiral shape on an outer peripheral surface.
According to the invention of Patent Document 1, since the adhesion force with the cement-type grout material is ensured by the nodes provided on the outer peripheral surface, the supporting force of the small-diameter pile can be sufficiently exhibited.

JP 2001-323459 A

However, the conventional technique has the following drawbacks.
Since the <1> small-diameter pile has a small diameter, the bending rigidity was not sufficient.
<2> When adopting small-diameter piles, many had to be placed in order to obtain a predetermined supporting force. Therefore, the construction cost was high.
<3> Construction of a pile was difficult because it used a large construction machine.

An object of the present invention is to provide a prestressed steel pipe pile having at least one of the following effects.
<1> Having high bending rigidity while having a small diameter.
<2> The number of placements can be reduced, and the construction cost can be reduced.
<3> Good workability and efficient construction even in narrow land.

  The prestressed steel pipe pile of the present invention for solving the above-described problems is sealed in a restraint pipe having both ends opened, two cap portions capable of sealing both ends of the restraint pipe, and the inside of the restraint pipe. , Having a total length that can be inserted through the constraining material and the constraining tube, having a reaction force in the cap part, tensioning the tensile material, and applying prestress to the constraining tube, It is characterized in that the consolidated material is restrained by a restraint tube.

  The prestressed steel pipe pile of the present invention is characterized in that the restraint pipe is constituted by a plurality of split restraint pipes, and the plurality of split restraint pipes are integrally connected by a tensile material.

  The prestressed steel pipe pile of the present invention is characterized in that the divided constraining pipes are connected by any one joining means of screwing, fitting, or welding.

  The prestressed steel pipe pile of the present invention is characterized in that the tensile material is any one of a PC steel bar, a PC steel stranded wire, an aramid fiber, or a combination thereof.

Since the prestressed steel pipe pile of the present invention has the above-described configuration, it has at least one of the following effects.
<1> Since prestress is imparted to the constraining pipe, high bending rigidity can be exhibited while having a small diameter.
<2> Since the bending rigidity is high, the number of casts can be reduced from the conventional small-diameter steel pipe pile. Moreover, the thickness of concrete can be reduced by reducing the number of placements when reinforcing existing structures. For this reason, construction cost can be reduced significantly.
<3> Since it has a small diameter, it can be placed with a small construction machine. Therefore, it can be easily constructed even in a narrow and dense construction place of a building, and the workability is very high.
<4> The divided restraint pipe can be succeeded. Therefore, it is possible to place a long steel pipe pile even in a place where the upper space of the placement place is restricted.

Explanatory drawing of the prestressed steel pipe pile which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. Explanatory drawing of Example 2 of this invention.

  Hereinafter, the prestressed steel pipe pile of the present invention will be described in detail with reference to the drawings.

[Prestressed steel pipe pile]
<1> Overall configuration (FIG. 1).
The prestressed steel pipe pile 1 of the present invention is a small-diameter steel pipe pile in which an axial tensile force is applied to the constraining pipe 10.
The prestressed steel pipe pile 1 includes a restraint pipe 10, a cap part 20, a consolidated material 30, and a tensile material 40.

<2> Restraint tube.
The restraint pipe 10 is a steel pipe that forms the main member of the prestressed steel pipe pile 1. In this example, an existing cylindrical steel pipe having a diameter of about 100 to 200 mm is employed.
On the peripheral surface of the constraining tube 10, a protrusion such as a node shape can be provided in order to improve the fixing property with the injection material 60 filled in the perforation 50.

<3> A cap part.
The cap parts 20, 20 are members that restrain both ends of the constraining tube 10 and constrain the consolidated material 30 in the constraining tube 10 while transmitting the compressive force of the tensile material 40 to the constraining tube 10.
The cap portion 20 includes a support plate 21 that closes the end portion of the restraining tube 10, a fixing tool 23 that is connected to the end portion of the tension member 40, and a presser material that transmits a compressive force applied to the fixing device 23 to the support plate 21. 22.
The bearing plate 21 is a circular plate-like body in this example. On the surface of the bearing plate 21 on the side of the restraint tube 10, a protrusion that fits into the inner surface of the restraint tube 10 is provided.
The bearing plate 21, the presser member 22, and the fixing tool 23 may be independent members or may be integrated.

<4> Consolidated material.
The consolidated material 30 is a curable filling material that fills the inside of the restraint tube 10.
In this example, a cement grout material is used for the consolidated material 30. Other materials such as mortar and synthetic resin can also be used.
The consolidated material 30 is cured and constrained in the constraining tube 10 so as to be integrated with the constraining tube 10 and improve the rigidity of the prestressed steel pipe pile 1.

<5> Tensile material.
The tension member 40 is a member that applies a compressive force due to prestress to the restraint tube 10 through the cap portion 20.
In this example, a PC steel rod is adopted as the tension member 40. Other known materials such as PC steel wires, PC steel strands, and aramid fibers can be used. A plurality of materials may be combined.
Both ends of the tension member 40 pass through the pressure plate 21 and the pressing member 22 of the cap portion 20 and are connected to the fixing tool 23.

[Prestressed steel pipe pile manufacturing method]
Then, the manufacturing method of the prestressed steel pipe pile of this invention is demonstrated in detail.

<1-1> Blocking of the first open end of the restraint tube.
The protruding portion of the support plate 21 is fitted into one open end of the restraint tube 10.
The presser material 22 is placed on the outer surface of the bearing plate 21.
The fixing tool 23 is connected to one end of the tension member 40, and the other end communicates with the presser member 22 and the central hole of the bearing plate 21, and protrudes from the opening on the opposite side of the restraint tube 10.

<1-2> Injection of consolidated material.
The restraint tube 10 is erected with the opening side facing upward, and the consolidated material 30 is filled into the restraint tube 10 to the vicinity of the edge.

<1-3> Covering of the second open end of the restraint tube (FIG. 2).
The opening side of the restraint tube 10 is covered with a bearing plate 21. At this time, the protruding portion of the bearing plate 21 is fitted into the tube of the restraint tube 10, and the tip of the tension member 40 is inserted into the central hole of the bearing plate 21.
The presser material 22 is installed on the upper part of the bearing plate 21. The tension member 40 is protruded from the center hole of the presser member 22.

<1-4> Introduction of prestress.
A reaction force is obtained from the pressure bearing plates 21 and 21 at both ends of the restraint tube 10, and the tension member 40 is tensioned with a jack or the like to apply a tensile force.
The fixing tool 23 is joined to the tension member 40, the jack is opened, and prestress is introduced into the restraint tube 10 through the cap parts 20 and 20.
The protruding end of the tension member 40 is cut to an appropriate length.

<1-5> Other methods.
The manufacturing method of the prestressed steel pipe pile 1 of this example is an example, and other well-known methods, for example, after sealing the both ends of the restraint pipe 10, inject | pour the consolidated material 30 from an injection hole, or introduce prestress It is also possible to adopt a pre-tension method.

<2> Prestress effect.
The restraint tube 10 is subjected to prestress by the tensile material 40 and is compressed in the axial direction, whereby the bending rigidity is increased.
Further, the consolidated material 30 in the constraining tube 10 also receives the compressive force of the tensile material 40 through the protruding portion of the bearing plate 21. This also improves the strength of the consolidated material 30 itself.
For this reason, a small-diameter pile having a pile diameter of about φ100 to 200 mm can be employed for a reinforcing structure or the like that has been conventionally constructed with a large-diameter cast-in-place pile or the like, and the construction cost can be greatly reduced. Moreover, since it can construct with a small apparatus, workability is very high.

[Another example of a constrained pipe divided structure]
Another embodiment in which the restraint tube 10 is connected to a plurality of split restraint tubes 10A will be described (FIG. 3).
In this example, the restraint tube 10 has a split structure, and is formed by connecting a plurality of split restraint tubes 10A in the axial direction.
A known joining means such as screwing, fitting, welding or the like is employed for connecting the divided restricting tubes 10A. A connecting mechanism 11 such as a screw portion for screwing may be provided at the end of the divided restricting tube 10A.
After connecting all the divided constraining pipes 10A, prestressing is applied to the cap parts 20 and 20 at both ends with the tensile member 40 communicating with the inside, and the divided constraining pipes 10A are compressed in the axial direction so as to be integrated. Link.
In the case of this example, since the short divided restraint pipes 10A can be inserted one by one into the perforation 50 and can be connected in the perforation 50, even if there is a spatial limitation above the placement site, the long A pre-stressed steel pipe pile 1 can be formed.

DESCRIPTION OF SYMBOLS 1 Prestressed steel pipe pile 10 Restraint pipe 10A Division | segmentation restraint pipe 11 Connection mechanism 20 Cap part 21 Supporting plate 22 Presser material 23 Fixing tool 30 Consolidated material 40 Tension material 50 Drilling

Claims (4)

A restraint tube open at both ends;
Two cap portions capable of sealing both ends of the restraint tube;
A consolidated material enclosed in the restraint tube;
A tensile material having a total length through which the restraint tube can be inserted, and
To give a reaction force to the cap portion, by said tension member is tensioned, it said has prestress is applied to the restraining tube, and wherein said caking material is restrained by the restraining pipe To
Prestressed steel pipe pile. 2. The prestressed steel pipe pile according to claim 1, wherein the constraining pipe is composed of a plurality of split constraining pipes, and the plurality of split constraining pipes are integrally connected by the tensile material. The prestressed steel pipe pile according to claim 2, wherein the divided constraining pipes are connected by any one joining means of screwing, fitting, or welding.   The prestress according to any one of claims 1 to 3, wherein the tensile material is any one of a PC steel bar, a PC steel strand, an aramid fiber, or a combination thereof. Steel pipe pile.

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