KR20210001657A - Earthquake-proof PHC pile with reinforced end - Google Patents

Abstract

The present invention relates to an earthquake-proof PHC pile with a reinforced end portion, which allows a spiral steel wire to surround the outside of a plurality of PC steel materials provided in a pile main body and has a reinforcing steel pipe on an end portion of the PC steel materials, thereby having excellent earthquake-proof performance, being safe against impact or stress concentration, and being easily manufactured. The earthquake-proof PHC pile with the reinforced end portion includes: a hollow pile main body made of concrete; a plurality of PC steel materials provided in the pile main body; a spiral steel wire provided to surround the outside of the plurality of PC steel materials; and a reinforcing steel pipe provided outside the PC steel materials at one end or both ends of the pile main body.

Description

Earthquake-proof PHC pile with reinforced end}

In the present invention, spiral wires surround the outside of a plurality of PC steels provided inside the pile body, while reinforcing steel pipes are provided at the ends of the PC steels, thereby providing excellent seismic performance, safe against impact or stress concentration, and easy to manufacture. It's about PHC files.

When the support layer of the ground is relatively deep, piles are used to transfer the load of the structure to the support layer.

The pile mainly supports the upper structure by the tip bearing force exerted by the pile tip being supported by the support layer and the principal surface friction force exerted by the friction between the main surface of the pile and the surrounding ground.

There are various types of such piles, such as steel pipe piles, cast-in-place concrete piles, and PHC piles, and they are selected and constructed differently depending on the type or depth of the supporting layer or the location of the target ground.

Among them, the Pretensioned spun High strength Concrete pile (PHC) is produced by applying prestress to PC steel, pouring concrete, and centrifugal molding. Accordingly, it is possible to have high loading capacity and impact resistance by supplementing the defects of concrete that are weak in bending or tensile force, and has the advantage of excellent economy and durability.

Nevertheless, PHC piles have less flexural, shear, or impact resistance than axial stiffness due to the characteristics of concrete. Therefore, it is inevitably relatively weak against lateral or impact loads compared to vertical loads.

In particular, damage such as cracks may occur in the upper part of the PHC pile due to the lateral load acting on the upper part of the PHC column, such as displacement of the upper structure or ground liquefaction during an earthquake. In addition, the PHC pile joint may also be damaged due to stress concentration in the concrete near the joint when lateral or tensile force is applied.

In addition, the PHC pile may have a crack at the top or bottom of the pile due to impact when hitting.

KR 10-1665361 B1

In order to solve the above problems, the present invention is to provide an end-reinforced seismic PHC file that is excellent in seismic performance, is safe against impact or stress concentration, and is easy to manufacture.

The present invention according to a preferred embodiment is a hollow pile body composed of concrete; A plurality of PC steels provided inside the pile body; Spiral wire provided to surround the outside of a plurality of PC steel; And a reinforcing steel pipe provided outside of the PC steel at one or both ends of the pile body. It provides an end reinforcement seismic PHC pile, characterized in that consisting of.

The present invention according to another preferred embodiment provides an end reinforced seismic PHC pile, characterized in that a plurality of flow holes are formed in the reinforced steel pipe.

The present invention according to another preferred embodiment provides an end reinforced seismic PHC pile, characterized in that the flow hole is formed in a square shape and arranged in a grid shape.

The present invention according to another preferred embodiment provides an end reinforced seismic PHC pile, characterized in that the flow hole is formed at the location of the PC steel.

The present invention according to another preferred embodiment provides an end reinforced seismic PHC pile, characterized in that a bent portion bent so as to protrude inward is provided between the left and right flow holes of the reinforcing steel pipe.

The present invention according to another preferred embodiment provides an end reinforced seismic PHC file, characterized in that a plurality of rows of skirt portions are extended at the lower end of the reinforcing steel pipe, and the upper portion of the spiral wire is configured to wind the outside of the skirt portion. .

According to the present invention, it is possible to provide a PHC pile in which a spiral wire is provided outside a plurality of PC steels provided inside the pile body, and a reinforcing steel pipe is provided at the end of the PC steel.

These PHC piles are easy to manufacture and have excellent seismic performance because reinforced steel pipes and spiral wires confine the internal concrete.

In addition, the reinforced steel pipe provided on the outside of the PC steel can effectively resist lateral force or impact force at the end of the PHC pile, increase the strength and ductility of the end, and constrain the concrete around the PC steel to concentrate stress at the anchoring area of the PC steel It can prevent concrete cracking.

1 is a perspective view showing an end reinforcement seismic PHC pile of the present invention.
2 is a perspective view showing a reinforced steel pipe in which a grid-shaped square flow hole is formed.
Figure 3 is a perspective view showing a PHC pile provided with the reinforced steel pipe of Figure 2;
4 is a perspective view showing a grid-shaped reinforced steel pipe in which a bent portion is formed.
5 is a perspective view showing a PHC pile provided with the reinforcing steel pipe of FIG. 4.
6 is a plan cross-sectional view of the PHC file shown in FIG. 5;
Fig. 7 is a cross-sectional view showing a cross section along A of the PHC pile shown in Fig. 6;
8 is a perspective view showing a reinforcing steel pipe provided with a skirt portion.
9 is a perspective view showing a PHC pile provided with the reinforcing steel pipe of FIG. 8.

Hereinafter, the present invention will be described in detail according to the accompanying drawings and preferred embodiments.

1 is a perspective view showing an end reinforcement seismic PHC pile of the present invention.

As shown in Fig. 1 and the like, the end reinforcement seismic PHC pile of the present invention includes a hollow pile body 1 made of concrete; A plurality of PC steels (2) provided inside the pile body (1); Spiral wire 3 provided to surround the outside of a plurality of PC steels 2; And a reinforcing steel pipe 4 provided outside the PC steel 2 at one or both ends of the pile body 1; It characterized in that it consists of.

The present invention is to provide an end-reinforced seismic PHC pile that is excellent in seismic performance, is safe against impact or stress concentration, and is easy to manufacture.

The present invention end reinforcement seismic PHC pile is a PHC pile manufactured by centrifugal molding.

The end reinforcement seismic PHC pile of the present invention includes a concrete pile body 1, a PC steel material 2, a spiral wire 3, and a reinforced steel pipe 4 having a hollow formed therein.

The PC steel 2 is for applying pretension to the concrete pile, and a plurality of PC steels 2 are embedded in the pile body 1 and can be disposed at equal intervals in the circumferential direction.

The PC steel 2 may have an enlarged head 21 formed at the end so that the end may be fixed to the shoe or cap (not shown) at the end of the PHC pile.

After the shoe or cap is bonded to the end of the PC steel 2, the shoe or cap is pulled with a tensioner to pour concrete while pre-tensioning is applied to the PC steel 2, and centrifugal molding to manufacture a hollow PHC pile.

The reinforcing steel pipe 4 is provided outside the PC steel 2 at one or both ends of the pile body 1.

That is, the reinforcing steel pipe 4 is provided in a certain section at one or both ends of the pile body 1.

Accordingly, the reinforcing steel pipe 4 can efficiently resist lateral force or impact force at the end of the PHC pile.

In addition, the reinforcing steel pipe 4 is provided outside the PC steel 2.

That is, the reinforcing steel pipe 4 is embedded inside the concrete pile body 1 like the PC steel material 2, but is located outside the concrete pile body 1 and is inside the pile body 1 except for the concrete covering. It is wrapped in concrete.

Accordingly, the reinforced steel pipe 4 confines the concrete inside the reinforced steel pipe 4 to increase end strength and ductility.

In particular, since the PHC pile is produced by pouring concrete while pretension is applied to the PC steel 2, stress concentration may occur in the concrete at the end of the pile where the PC steel 2 is fixed.

Therefore, by providing a reinforcing steel pipe 4 outside the PC steel 2, the concrete around the PC steel 2 is constrained at the end of the PC steel 2 to prevent concrete cracking at the anchoring site of the PC steel 2 You can do it.

The spiral wire 3 is provided to surround the outside of the plurality of PC steels 2.

The spiral wire 3 is installed to wrap around the PC steel 2 to constrain the concrete inside.

In the present invention, since the reinforced steel pipe 4 itself can perform the role of the spiral wire 3 by constraining the internal concrete, the spiral wire 3 is disposed only in the remaining unreinforced sections except for the part where the reinforced steel pipe 4 is installed. It may be configured as possible.

A plurality of flow holes 41 may be formed in the reinforced steel pipe 4.

The PHC pile can be manufactured by mounting the PC steel 2 and the spiral wire 3 on the upper part of the semi-cylindrical lower mold (not shown), filling the lower mold with concrete, and then combining the upper mold.

At this time, when the reinforcing steel pipe 4 of the closed section is installed at the end of the PHC pile, concrete may not be filled inside the reinforced steel pipe 4 due to interference of the reinforcing steel pipe 4.

In addition, even in the centrifugal molding process, there is a possibility that the PHC pile having a uniform thickness cannot be manufactured due to the interference of the reinforcing steel pipe 4, because the concrete is not tightly filled outside the reinforcing steel pipe 4.

Accordingly, a plurality of flow holes 41 may be formed in the reinforcing steel pipe 4 to secure a uniform thickness of concrete flesh.

In addition, since the concrete and the reinforcing steel pipe 4 are made of different materials from each other, interfacial separation may occur under high stress, resulting in cracks. However, if concrete is filled in the flow hole 41 and the concrete and the reinforcing steel pipe 4 are integrated, it is possible to prevent separation of the interface between them.

FIG. 2 is a perspective view illustrating a reinforced steel pipe in which a grid-shaped square flow hole is formed, and FIG. 3 is a perspective view illustrating a PHC pile provided with the reinforced steel pipe of FIG. 2.

As shown in FIGS. 2 and 3, the flow hole 41 may be formed in a square shape and configured to be arranged in a grid shape.

When the flow holes 41 are formed in a square shape and arranged in a grid shape in a plurality of rows, a portion of the reinforcing steel pipe 4 between the adjacent flow holes 41 can be configured to be relatively narrow.

Accordingly, deformation of the reinforced steel pipe 4 is allowed against axial force or lateral force, so when an external impact such as driving or light hitting acts on the reinforced steel pipe 4, or when a repeated load such as an earthquake is applied, the reinforced steel pipe 4 is subjected to external energy. Can absorb and dissipate.

That is, the reinforcing steel pipe 4 can constrain the internal concrete to increase the strength and ductility of the concrete, as well as absorb and dissipate energy by self-deformation, thereby greatly improving the seismic performance of the PHC pile.

The flow hole 41 may be configured to be formed at the position of the PC steel material 2.

If the concrete is not sufficiently wrapped around the PC steel material 2, the adhesion between the PC steel material 2 and the concrete decreases.

In particular, when there is no shoe or cap at the end of the PHC pile, pre-tension is applied to the entire pile body 1 by the frictional force between the PC steel 2 and the concrete. However, at this time, if the adhesion between the PC steel 2 and the concrete is small, the stress is not properly transmitted.

Therefore, by configuring the flow hole 41 to correspond to the position of the PC steel 2, it is possible to secure sufficient concrete around the PC steel 2.

4 is a perspective view illustrating a grid-shaped reinforced steel pipe in which a bent portion is formed, and FIG. 5 is a perspective view illustrating a PHC pile provided with the reinforcing steel pipe of FIG. 4. And FIG. 6 is a top cross-sectional view of the PHC pile shown in FIG. 5, and FIG. 7 is a cross-sectional view showing a cross section along A of the PHC pile shown in FIG. 6.

As shown in FIGS. 4 to 7 and the like, between the left and right flow holes 41 of the reinforcing steel pipe 4 may be provided with bent portions 42 that are bent to protrude inward.

Even if the flow hole 41 of the reinforcing steel pipe 4 is installed to be placed at the position of the PC steel material 2, the flow hole 41 and the PC steel material ( The positions of 2) can be mixed.

Therefore, the reinforcing steel pipe 4 between the flow holes 41 located on the left and right is formed to be bent inward so that the side of the PC steel 2 is caught on the bent part 42, so that the reinforced steel pipe 4 is formed in the centrifugal forming process. ) Can prevent the position of the flow hole 41 and the PC steel material 2 from being changed (FIG. 6).

In addition, as shown in FIG. 7, since the bent portion 42 forms a zigzag-shaped bend in the reinforcing steel pipe 4 in a cross-sectional view, the reinforcing steel pipe 4 and the concrete pile body ( 1) can be further integrated.

In addition, if the rigidity of the reinforced steel pipe 4 is too large, the compressive deformation of the PHC pile is concentrated in the PHC pile body 1 of the unreinforced portion without the reinforced steel pipe 4, so that the compressive stress of the unreinforced portion may increase excessively. I can.

However, when the part of the reinforcing steel pipe 4 on the left and right of the flow hole 41 is bent as described above, since deformation occurs relatively freely in the bent part 42 against the compressive force, it is possible to prevent an increase in the compressive stiffness of the reinforcing part.

Accordingly, it is possible to prevent an increase in compressive stress on the unreinforced portion of the PHC pile body 1 by suppressing an increase in end axial stiffness against axial load while reinforcing the ends against lateral loads or impact loads. As a result, it is possible to exhibit very efficient seismic performance structurally.

8 is a perspective view illustrating a reinforced steel pipe provided with a skirt portion, and FIG. 9 is a perspective view illustrating a PHC pile provided with the reinforced steel pipe of FIG. 8.

8 and 9, a plurality of rows of skirt portions 43 are extended at the lower end of the reinforcing steel pipe 4, and the upper portion of the spiral wire 3 extends the outside of the skirt portion 43. Can be configured to wind.

When the spiral wire 3 is provided only in the unreinforced section of the PHC pile body 1, the distance between the spiral wire 3 and the reinforced steel pipe 4 may be distant during the manufacturing process, resulting in a concrete unconstrained section.

Therefore, the skirt part 43 is extended so that the reinforced steel pipe 4 and the spiral wire 3 overlap for a predetermined period, and the end of the spiral wire 3 may be configured to surround the skirt part 43.

The end of the spiral wire 3 can be fixed to the skirt part 43 by tag welding.

The skirt part 43 may be bent inward by the thickness of the spiral wire 3 than the main body of the reinforcing steel pipe 4 so that the cover thickness of the spiral wire 3 can be secured even in the skirt part 43 section.

The skirt part 43 is not only a part to which the spiral wire 3 is joined, but also distributes the stress at the part where the end of the reinforcing steel pipe 4 and the pile body 1 meet, and acts as a shear connector to integrate these members. Contribute.

1: the file body
2: PC steel
21: enlarged head
3: Spiral wire
4: reinforced steel pipe
41: flow hole
42: bend
43: skirt part

Claims (6)

A hollow pile body 1 made of concrete;
A plurality of PC steels (2) provided inside the pile body (1);
Spiral wire 3 provided to surround the outside of a plurality of PC steels 2; And
A reinforced steel pipe 4 provided outside the PC steel 2 at one or both ends of the pile body 1; End reinforcement seismic PHC file, characterized in that consisting of.
In claim 1,
End reinforced seismic PHC pile, characterized in that a plurality of flow holes (41) are formed in the reinforced steel pipe (4).
In paragraph 2,
The flow hole 41 is formed in a square shape, characterized in that the end reinforcement seismic PHC file arranged in a grid.
In claim 2 or 3,
The flow hole 41 is an end reinforced seismic PHC pile, characterized in that formed at the location of the PC steel (2).
In claim 4,
End reinforced seismic PHC pile, characterized in that a bent portion 42 bent so as to protrude inward is provided between the left and right flow holes 41 of the reinforced steel pipe 4.
In claim 1,
End reinforcement seismic resistance, characterized in that a plurality of rows of skirt portions 43 are extended at the lower end of the reinforcing steel pipe 4, and the upper portion of the spiral wire 3 is configured to wind the outside of the skirt portion 43 PHC file.

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