JP2014101716A - Pre-stressed concrete pile and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pre-stressed concrete pile with a solid structure which is constituted to comply with JIS standard A5373.SOLUTION: A pre-stressed concrete pile includes PC steel and reinforcement bars, which are placed in the axis direction of a pile having a generally uniform cross section, and which have a reinforcement ratio of 0.4% or higher and include at least six reinforcement bars in the total area of the pile's cross section. The pre-stressed concrete pile comprises: six or more axis-direction reinforcement bars 12 which are arranged at equal angle intervals on a circle with a certain radius; and a pile main body 15, which has a polygonal cross section, has some or all of the corners of the polygon disposed at positions corresponding to some or all of the six or more axis-direction reinforcement bars, and is completely filled with concrete 14 between its outer surface and axis.

Description

  The present invention has a PC steel and a reinforcing bar arranged in the axial direction of a pile having a substantially uniform cross-sectional shape, and the PC steel and the reinforcing bar have a reinforcing bar ratio of 0.4% or more based on the total cross-sectional area, and Further, the present invention relates to a prestressed concrete pile having six or more and its manufacturing method.

  For example, so-called factory-made prestressed concrete piles are used as underground driving piles for the purpose of improving soft ground (here, “made by factory” is used in terms of, for example, comparison with on-site driving). Prestressed concrete piles (pile) are described in Japanese Industrial Standards JIS, A5373. In Annex E (normative) piles, E-1.5 reinforcement, PC pile reinforcement is as follows: Several criteria are given. Prestressed concrete piles that meet this standard are prestressed concrete piles that conform to JIS standards, and other types of concrete piles that have similar shapes and structures cannot be prestressed concrete piles that conform to JIS standards.

  According to the above criteria, first, “a) PC steel materials and rebars arranged in the axial direction have a rebar ratio of 0.4% or more based on the total cross-sectional area and the number of bars is 6 or more. In order to reduce the direction of the bending strength of the pile, the perforation of the PC steel and the reinforcing bar should be at least one time the maximum size of the coarse aggregate. It should be 4/3 times or more. " In addition, “b. The helical reinforcing bar is arranged outside the axial PC steel material and the axial reinforcing bar. The helical reinforcing bar has a wire diameter of 3 mm or more when the outer diameter of the pile is 500 mm or less, and a wire when the outer diameter of the pile is 600 to 1000 mm. Standards such as “4 mm or more in diameter, 5 mm or more in wire diameter in the case of 1100 mm and 1200 mm of piles, pitch of 110 mm or less, c.

  Prestressed concrete piles (pile) according to this standard have been widely used, but have been conventionally manufactured by centrifugal molding, and some problems can be pointed out. As one of them, in the centrifugal molding method, after placing the reinforcing steel cage in the steel cylindrical formwork, the formwork into which the concrete has been put is used to compact the concrete using centrifugal force. This is inevitably caused by the fact that it has a hollow cylindrical shape. That is, if the structure is a hollow structure, the tip supporting force tends to be insufficient as it is, and therefore it is necessary to select a pile with a larger diameter in order to obtain a sufficient bottom area. Also, in the case of centrifugal molding, concrete filling, commonly called “junka”, tends to be insufficiently filled, and it is difficult to produce a small diameter because a belt conveyor or chute for supplying concrete is inserted into the mold, and when PC steel is in tension There is a situation that the formwork itself must be able to withstand the reaction force that occurs in the manufacturing process. For this reason, the price of the manufacturing apparatus is high, and a great burden is imposed on the equipment investment. Furthermore, since it is a cylindrical type, it is difficult to obtain stability unless rolling is prevented, and there is a danger, so care must be taken for stacking during storage.

Under such circumstances, the applicant of the present invention has been carrying out diligent development research with the objective of providing prestressed concrete piles that satisfy the standards of JIS and A5373 without relying on the centrifugal molding method. As a result, the non-hollow, solid structure polygonal pile is significant as a prestressed concrete pile with a reinforcing bar ratio of 0.4% or more in terms of the total cross-sectional area and 6 or more reinforcing bars. Was recognized. For example, a polygonal pile has the following characteristics.
1) Advantages of manufacturing equipment: It is possible to manufacture by casting, which is impossible with a hollow cylindrical structure, and since there is no need for centrifugal molding equipment, the capital investment is small, and the manufacturing equipment can be moved or moved. Easy.
2) Structural advantages: Rebars can be placed more accurately and evenly, and unevenness of rebars, lack of rebar cover and variations can be eliminated. Further, the stress can be more evenly distributed, and the cross-sectional force resisting the horizontal force has no directivity.
3) Advantages in manufacturing: Casting is possible and partitioning in the mold is easy, so the length of the concrete pile can be freely determined, and since it is a solid structure, it is smaller than that of the hollow structure. A sufficient bottom area can be obtained even with the diameter, and the tip supporting force is further increased.
4) Advantages after production: Since it is a square concrete pile, it is difficult to roll, the load is easy and stable. Therefore, a stopper for preventing rolling is not required during transfer or during transportation, and stacking is easy at the storage place and contributes to space reduction.

  Examining the prior art, there is Japanese Patent Laid-Open No. 10-1000012, and the invention of the same proposes a mold structure with a split structure that makes it easy to remove the mold form from the pile. But not more than that. In addition, the one having a hexagonal cross-sectional shape is disclosed in Japanese Patent Application Laid-Open No. 2002-327434, which describes that the strength against torsion is high, the bite into the surrounding ground at the time of driving is high, and the familiarity is improved. However, some of them are in common with the present invention. However, a manufacturing apparatus using a centrifugal molding method is required, and the outer shape is hexagonal. However, only four pieces of PC bar are used and do not satisfy the standards of JIS and A5373.

JP-A-10-1000012 JP 2002-327434 A

  This invention is made | formed in view of the said situation, The subject is providing the prestressed concrete pile with a solid structure comprised so that the specification of JIS and A5373 might be satisfy | filled. Moreover, the other subject of this invention is providing the method which can manufacture said prestressed concrete pile, without using a centrifugal forming method.

  In order to solve the above-mentioned problem, the present invention has a PC steel material and a reinforcing bar arranged in the axial direction of a pile having a substantially uniform cross-sectional shape, and the PC steel material and the reinforcing bar have a reinforcing bar ratio according to the total cross-sectional area thereof. 0.4 or more and 6 or more prestressed concrete piles, 6 or more axial reinforcing bars arranged at equal angular intervals on the circumference of a certain radius, and polygons A part of or all of the corners of the polygon are arranged at a position that coincides with part or all of the six or more axial rebars, and the axial center from the outer surface. The pile main body filled with concrete is taken and the means of having a structure is taken.

  In the prestressed concrete pile according to the present invention, the PC steel material and the axial rebar arranged in the axial direction of the pile have a certain numerical condition that the rebar ratio by the total cross-sectional area is 0.4% or more and 6 or more. It satisfies. The above numerical conditions are a part of JIS, A5373, which is the basic rule for bar arrangement. Other conditions relating to the bar arrangement include a. In addition, the perforation of the PC steel material and the reinforcing bar is at least 1 time of them and at least 4/3 times the maximum size of the coarse aggregate, c. In addition, there is a standard such that the cover of the PC steel material and the helical rebar (corresponding to the circumferential rebar in the present invention) is 15 mm or more. The prestressed concrete pile of the present invention naturally satisfies these conditions, but conditions other than the numerical conditions relating to the bar arrangement belong to common sense for those engaged in the manufacture of concrete piles, and naturally comply with them. It is judged that it is a matter before the provisions to be made. Therefore, the above numerical condition is a constituent requirement of the present invention from the viewpoint that if the basic rules are observed, the subsequent conditions are also necessarily observed.

  The prestressed concrete pile according to the present invention needs to have six or more axial reinforcing bars arranged at equal angular intervals on the circumference of a certain radius. The six or more axial rebars correspond to the positions of the polygonal corners. The axial rebar here is a part of a reinforcing mesh rebar composed of an axial rebar and a circumferential rebar. On the other hand, six PC steel materials may be used, but every other one may be three half and can be changed according to the length of the concrete pile and other conditions. PC steel is a means for imparting prestress to prestressed concrete piles, and stranded wires (twisted wires) obtained by twisting PC steel wires are frequently used. The PC steel material is also called a PC steel wire or a PC steel bar.

  The pile body basically has a polygonal cross-sectional shape, and a part or all of the corners of the polygon are arranged at a position where the part or all of the six or more axial rebars coincide. And it has the structure of being filled with concrete from an outer surface to an axial center. The reason for making the pile body a regular polygon in the cross-sectional shape is to make it easier to match the corners of the axial rebars, and by matching the corners, more accurate even placement of the reinforcing bars is possible, This is because deficiencies and variations in the amount of reinforcing steel cover can be resolved. Moreover, the reason why the pile body has a solid structure is that a sufficient bottom area can be obtained even with a smaller diameter, and an increase in the tip support force can be expected.

  In particular, the pile body has hexagonal or more corners in the cross-sectional shape, and a part or all of the corners are arranged so as to coincide with part or all of the six or more axial rebars. It is desirable. This is because it is the minimum configuration that satisfies the conditions of the number of PC steel materials and reinforcing bars described in the section of bar arrangement in JIS, A5373, and can be said to be the most rational. In addition, the concrete piles can be arranged more accurately and evenly as concrete piles, and the load is easy and stable because it is the most difficult form to roll. However, as long as the cross-sectional shape of the pile body does not conflict with the bar arrangement according to the conditions of the above JIS standard, any polygon can be selected, and the polygon shape of the pile body and the polygon shape formed by the axial rebar However, the form which does not correspond, for example, a hexagon and 12 corners, can also be selected.

  The method for producing the prestressed concrete pile according to the present invention is as follows. That is, six or more axial rebars and circumferential reinforcing bars are combined vertically and horizontally to form a reinforcing rebar, and the reinforcing rebar is bent at the position of six or more axial rebars. A process of forming a polygonal columnar rebar having hexagonal or more corners, a part or all of six or more axial rebars arranged in the axial direction of a pile have a polygonal cross-sectional shape Place the PC steel material inside the formwork so as to match the corners of the formwork, place the PC steel inside the formwork and tighten it with a tensioning device, close the formwork and pour concrete mortar into it The method that goes through the process is taken. The prestressed concrete pile of the present invention obtained by this manufacturing method naturally has axial rebars arranged in the axial direction of the pile having a uniform cross-sectional shape, and the above-mentioned axial rebar and PC steel are the total crossing thereof. The condition that the reinforcing bar ratio by area is 0.4% or more and 6 or more is satisfied.

  Polygonal columnar rebars with hexagonal or more corners are formed by bending the reinforcing rebars at the position of six or more axial rebars, and through this process, the plane is accurately reinforced. Reinforcing bars can be easily formed. The axial reinforcement of the reinforcing mesh reinforcement is positioned accurately, so the axial reinforcement accurately defines the bending position, and the polygonal column reinforcement with hexagonal corners or more is accurately formed. become. In this way, a part or all of the six or more axial rebars are arranged inside the mold in accordance with the position of the corner of the mold having a polygonal cross-sectional shape, PC steel can be placed inside the mold and tensioned by a tensioning device. In the present invention, the concrete mortar is poured into the mold, that is, cast molding is possible. As a result, the initial cost for implementation can be reduced, and many advantages can be obtained such as the movement of the manufacturing apparatus.

  Since the present invention is configured as described above, it has a minimum configuration that satisfies the standards of JIS and A5373 and satisfies the conditions of the number of PC steel materials and axial reinforcing bars described in the section of reinforcement. In addition to providing the prestressed concrete pile, it is possible to arrange the reinforcing bars more accurately and evenly as the concrete pile, and it is possible to eliminate the unevenness of the reinforcing bars, the shortage of the covering amount of the reinforcing bars, and the variation. In addition, according to the present invention, since the above prestressed concrete pile can be manufactured without using the centrifugal molding method, the capital investment can be reduced, and an accurate product in conformity with the JIS standard can be manufactured. In addition, the manufacturing process proceeds safely. Further, the manufacturing apparatus can be easily moved or moved, and can provide a method in place of the centrifugal molding method.

Hereinafter, the present invention will be described in more detail with reference to illustrated embodiments.
<Prestressed concrete pile>
FIG. 1 shows an example of a prestressed concrete pile 10 according to the present invention. This prestressed concrete pile 10 includes six axial reinforcing bars 12 arranged at equal angular intervals on a constant radius circumference. The cross-sectional shape has hexagonal corners 13, the corners 13 are arranged at positions corresponding to some or all of the six axial rebars 12, and the concrete 14 extends from the outer surface to the shaft core. And a pile body 15 filled with Reference numeral 16 denotes a circumferential reinforcing bar, which is integrated with the axial term reinforcing bar 12 to constitute a reinforcing structural material. The pile body 15 is penetrated by a PC steel material 11 that applies a compressive force inwardly in the axial direction to the pile.

The PC steel material 11 in the illustrated embodiment has a stranded (twisted wire) structure in which three single-wire PC steel wires are twisted (FIGS. 2 and 3). In the example of FIG. 2, the hexagonal column-shaped pile body 15 has six axial rebars 12, whereas the PC steel material 11 has three halves for every other arrangement. The prestressed concrete pile of this example is denoted by reference numeral 10-1. The example in FIG. 3 has six PC steel members 11 and six axial reinforcing bars 12 for the hexagonal columnar pile body 15, and the prestressed concrete pile of this example is denoted by reference numeral 10-2. In addition, the maximum diameter of the pile main body 15 in the illustrated embodiment is 200 mm. Therefore, the cross-sectional area is 25948.3 mm ² .

In the example of FIG. 2, the PC steel material 11 is composed of three wires having a diameter of 2.9 mm, which are arranged at equal angular intervals on the circumference of the three bundles, and the axial rebar 12 has a diameter of 3 It consists of a single wire of 2 mm, and it is arranged at equiangular intervals on the circumference of 6 wires. The example of FIG. 2 is a setting regarding the pile body 15 having a maximum diameter of 200 mm and a length of 6.0 m or less.
PC steel cross-sectional area, φ2.9: 3 (19.82) × 3 = 59.46 mm ²
Cross section of axial rebar, φ3.2: 8.04 × 6 = 48.24 mm ²
Total cross-sectional area of rebar, = 107.7mm ²
The ratio of the total cross-sectional area of the reinforcing bar to the total cross-sectional area of the reinforcing bar in this example is
107.7 / 25948.3 = 0.0001.
That is, 0.41> 0.4 (JIS, A5373),
Therefore, the reinforcing bar ratio is 0.41%, which satisfies the numerical conditions in the constituent requirements of the invention.

Further, the PC steel material 11 in the example of FIG. 3 is composed of three strands having the same diameter of 2.9 mm as described above, which are arranged at equiangular intervals on the circumference of the six bundles, and the axial rebar 12 has a diameter It consists of a single line of 3.2 mm, and it is arranged at equiangular intervals on six circumferences. In this case,
Total cross-sectional area of rebar, 59.46 × 2 + 48.24 = 167.16 mm ²
Since the cross-sectional area of the pile body 15 does not change,
167.16 / 25948.3 = 0.0004.
The reinforcing bar ratio is 0.64%, and it is clear that the numerical condition in the constituent requirements of the invention is satisfied.

  The prestressed concrete pile 10 according to the present invention configured as described above is JIS, A5373, Annex E (normative) piles, other conditions related to E-1.5 bar arrangement, that is, the opening of PC steel and rebar. , More than 1/3 of them, and more than 4/3 times the maximum size of coarse aggregate, and cover of PC steel 11 and axial rebar 12 (spiral rebar) should meet 15mm or more. Designed and manufactured. Therefore, more even distribution of stress is possible, the direction of cross-sectional force resisting horizontal force is lost, and since it is a solid structure, a sufficient bottom area can be obtained even with a smaller diameter than that of a hollow structure, In addition, since it is a square concrete pile with increased tip support force, it is difficult to roll, and the load is easy and stable.

<Prestressed concrete pile manufacturing method>
The manufacturing method of the prestressed concrete pile concerning this invention passes through the following processes, as described in the structure of invention.
Six or more axial rebars and circumferential reinforcing bars are combined vertically and horizontally to form a reinforcing rebar, and the reinforcing rebar is bent at the position of six or more axial rebars so that it is hexagonal or more. The process of forming a polygonal columnar rebar with the corners.
A part or all of the six or more axial rebars arranged in the axial direction of the pile are aligned with the corners of the formwork having a polygonal cross-sectional shape inside the formwork. The step of arranging the PC steel material inside the mold and tensing it with a tensioning device.
Closing the above formwork and pouring concrete mortar into it.

The manufacturing method of the present invention will be specifically described with reference to the embodiment shown in FIG.
<Process for forming polygonal columnar rebar>
In the example shown in the drawing, first, the reinforcing mesh reinforcing bar 17 is formed by combining six axial reinforcing bars 12 and an arbitrary number of circumferential reinforcing bars 16 vertically and horizontally (FIG. 4). Reinforcing bars used for the axial reinforcing bars 12 and the circumferential reinforcing bars 16 are steel wires having a diameter of 3.2 mm. These vertical and horizontal wire elements are welded at intersections to constitute an integral reinforcing rebar 17.
Next, the reinforcing mesh reinforcing bar 17 is bent at the position of the six axial reinforcing bars 12, thereby forming a polygonal columnar mesh reinforcing bar 18 having hexagonal corners (FIG. 5).

  The six reinforcing bars 12 and the arbitrary number of circumferential reinforcing bars 16 are combined vertically and horizontally to form a reinforcing reinforcing bar 17 having a desired length. Bending at the position of the directional rebar 12 and forming the polygonal columnar rebar 18 having hexagonal corners is achieved by welding according to a predetermined dimension and bending the steel material at a fixed position. Since no special device or technique is required, it is possible for a person who has a standard technical level to easily manufacture. As a result, the polygonal columnar rebar 18 having hexagonal corners can be formed easily and accurately.

<Process of arranging the polygonal columnar rebar inside the formwork>
An outline of a manufacturing apparatus for a prestressed concrete pile having a formwork 20 and a PC steel material tensioning device 21 for this process will be described with reference to FIGS. As shown in FIG. 6, the mold 20 for forming the pile body 15 has an elongated shape in which a hexagonal groove-like space 19 is formed inside, and tensions the PC steel material 11. It arrange | positions inside the tension apparatus 21 which consists of a pressure | voltage resistant flame | frame to make. The mold 20 itself has a mold structure in which each side surface is sealed except for an upper surface on which concrete is poured. The PC steel material 11 penetrates the left and right end faces of the mold 20 and extends to the outside of the mold.
One end of the PC structural member 11 is fixed to the right end portion 22 in FIG. 6 of the PC steel material tensioning device 21, and the other end is attached to a pulling head (tension transmission portion) 24 on the left end portion 23 side of the same figure. In FIG. 7, 11 a is a detachable connection grip that connects two PC steel materials 11, 11, and 11 b is a fixing grip that fixes the PC steel material 11 to the pulling head 24. A tension bar 25, which is a tension member, is connected to the pulling head 24, and a tension force is applied to the PC steel material 11 by a jack (pressure means) 26 acting on the tension bar 25. The jack 26 is attached to a pedestal 27 composed of a ram chair, and is extended in the axial direction by hydraulic pressure supplied from a hydraulic pump (pressure generating unit) 28 to drive the tension bar 25. The pedestal portion is provided with a fixing bolt 27a that is tightened so that the jack 26 does not continue to operate during curing. The right end portion 22 of the PC steel material tensioning device 21 is provided with six through holes 29 through which the PC steel material 11 is passed, and a bolting portion 30 is provided as a part of the tension bar 25 that tensions the PC steel material 11. It is provided on the central axis (FIG. 8).
The standard cross section of the mold 20 has the configuration shown in FIG. 9 and is arranged at the center of the horizontal cross section of the base of the PC steel material tensioning device 21 with one side of the hexagon of the mold 20 arranged horizontally. ing. 31 is a formwork opening, and this part is hermetically sealed by a lid member (not shown) when filling concrete. The left end side is closed with an end plate, and six through holes 32 through which the PC steel material 11 is passed are provided equally. As shown in the figure, the mold 20 is generally composed of two upper and lower portions, and the joints of both portions are sealed by a packing 33 for liquid tightness.

Each process is performed as follows.
Reinforcing bar formation process It is a process for forming a polygonal columnar rebar. In this step, the reinforcing rebar 17 formed in the shape shown in FIG. 4 is bent 60 degrees at the position of the axial rebar 12 to form a polygonal columnar rebar 18 having hexagonal corners. The polygonal columnar rebar 18 is formed so that the position of the axial rebar 12 is exactly at the same position as each corner of the regular hexagon. The bent circumferential reinforcing bars 16 are set so as to overlap each other at both ends thereof (see FIG. 5, the overlapping ends may be left as they are or may be joined).

Formwork placement step is a step of placing the polygonal columnar rebar 18 in the formwork 20. Since the method of the present invention is horizontal molding, the mold 20 is installed horizontally. In this step, some or all of the six PC steel members 11 and the axial reinforcing bars 12 arranged in the axial direction of the piles constituting the polygonal columnar rebar 18 are hexagonal in the cross-sectional shape. Alternatively, they are arranged inside the mold 20 so as to coincide with the corner positions of the mold 20 having multiple corners (see FIGS. 6 to 9). FIG. 9 also shows that the through holes 32 through which the PC steel material 11 passes coincide with the six corners of the mold 20. In addition, the end members having the through holes 29 and 32 through which the PC steel material 11 is passed are firmly fixed to the mold 20 and the base of the PC steel material tensioning device 21. Accordingly, the polygonal columnar rebar 18 is accurately positioned with respect to the formwork 20, and the number thereof is six or more, and is arranged as evenly as possible along the concentric circles in each cross section of the pile. The criteria will be met exactly. This step is a prestressing step in which an axial and inward compressive force is applied to the concrete pile. For this purpose, a required tension force is applied to the PC steel material 11 by the tensioning device 21.

Molding process A process in which concrete mortar is poured into the mold 20. In the production method of the present invention, concrete is filled by casting. First, after placing concrete mortar and solidifying the filled concrete through a curing period, the connection grip 11a is separated, and the removable part including the lid that has closed the mold opening 31 is removed and removed. Do the mold. The product taken out by demolding, that is, the prestressed concrete pile 10 according to the present invention is laid down in a storage place. At that time, since the manufacturing method according to the present invention is formed sideways as described above, it may be moved by a crane or the like while sideways (in addition, since it has a polygonal cross-sectional shape, it rolls like a cylindrical pile). No worries).

  The prestressed concrete pile 10 according to the present invention illustrated in FIG. 1 and the like is manufactured through the above steps. In FIG. 6, although the intermediate part of the manufacturing apparatus which consists of the said formwork 20 and the PC steel material tension | tensile_strength apparatus 21 is abbreviate | omitted, this can change the length, and, thereby, many picks from one pick Until now, it has shown that the prestressed concrete pile 10 can be manufactured freely. In particular, in the case of the manufacturing method of the present invention, since it is formed sideways as described above, it is easy to partition the inside of the formwork, and the length of the prestressed concrete pile 10 to be manufactured can be freely determined by changing the partition position. can do. Although such a partitioning device will not be described in detail, a partition member may be installed inside the mold 20 depending on the length of the prestressed concrete pile 10 to be manufactured. be able to.

  The prestressed concrete pile 10 according to the present invention is configured as described above, and satisfies the conditions described in Japanese Industrial Standards JIS, A5373, in particular, Annex E (normative) piles, E-1.5 bar arrangement. It is possible. About this prestressed concrete pile 10, since the pile main body 15 with the angle | corner which consists of a regular polygon has the axial rebar 15 of six or more pieces, the cross-sectional shape of the pile main body 15 is regular six It is not limited to a square shape, and can take a form such as a regular square. Therefore, it is possible to combine the pile main body 15 with a regular octagon and six axial reinforcing bars. However, when the pile main body 15 is an octagonal shape, the number of the axial reinforcing bars 12 is eight. However, design and manufacture will be easier. Also, it is not impossible to take a square cross-sectional shape, and in fact, by arranging the diagonal of the square pile body and the two most distant corners of the six axial reinforcing bars, It can be easily understood that the configuration of the invention can be satisfied. The combination of the six axial rebars 12 and the hexagonal pile body 15 described in the embodiment is a case that is considered to satisfy the JIS standard most reasonably, but there are many suboptimal cases. As for the cross-sectional shape of the pile body 15, it is sufficient if a polygon is a requirement.

It is a partial cross section side view which abbreviate | omits and shows the example of the prestressed concrete pile which concerns on this invention. It is explanatory drawing which shows Example 1 of the cross section of a prestressed concrete pile same as the above. It is explanatory drawing which shows the example 2 of the cross section of a prestressed concrete pile similarly. It is a partial front view which shows an example of the reinforcing mesh reinforcement used for the manufacturing method of the prestressed concrete pile which concerns on this invention. It is a perspective view which similarly shows an example of a polygonal columnar rebar. It is an upper surface explanatory drawing which abbreviate | omits and shows the manufacturing apparatus which consists of a formwork and PC steel material tension apparatus similarly used in the manufacturing method of this invention. It is explanatory drawing which shows an example of the PC steel material tension | tensile_strength means in a manufacturing apparatus same as the above. It is explanatory drawing regarding the edge part of a manufacturing apparatus same as the above. It is a cross-sectional view of the standard part in a manufacturing apparatus same as the above.

10, 10-1, 10-2 Prestressed concrete pile 11 PC steel 12 Axial rebar 13 Corner 14 Concrete 15 Pile body 16 Circumferential rebar 17 Reinforcement rebar 18 Polygonal column rebar 19 Grooved space 20 Formwork 21 Tension device 22 right end 23 left end 24 pulling head (tension transmission part)
25 Tension bar (tension member)
26 Jack (Pressurizing means)
27 Pedestal 28 Hydraulic pump (pressure generator)
29, 32 Through-hole 30 Bolt tightening part 31 Formwork opening part 33 Packing (liquid-tight means)

Claims (3)

PC steel and reinforcing bars arranged in the axial direction of a pile having a substantially uniform cross-sectional shape. The PC steel and reinforcing bars have a reinforcing bar ratio of 0.4% or more and 6 or more by their total cross-sectional area. Is a prestressed concrete pile,
6 or more axial rebars arranged at equal angular intervals on a constant radius circumference;
It has a polygonal cross-sectional shape, and part or all of the corners of the polygon are arranged at positions corresponding to some or all of the six or more axial reinforcing bars, and from the outer surface A prestressed concrete pile having a pile body filled with concrete up to the shaft core. PC steel and reinforcing bars arranged in the axial direction of a pile having a substantially uniform cross-sectional shape. The PC steel and reinforcing bars have a reinforcing bar ratio of 0.4% or more and 6 or more by their total cross-sectional area. A method for producing a prestressed concrete pile,
Six or more axial rebars and circumferential reinforcing bars are combined vertically and horizontally to form a reinforcing rebar, and the reinforcing rebar is bent at the position of six or more axial rebars so that it is hexagonal or more. Forming a polygonal columnar rebar with the corners of,
A part or all of the six or more axial rebars arranged in the axial direction of the pile are aligned with the corners of the formwork having a polygonal cross-sectional shape inside the formwork. A step of placing the PC steel material inside the formwork and tensioning with a tensioning device,
The manufacturing method of the prestressed concrete pile characterized by passing through the process of pouring concrete mortar in the inside while closing the said formwork. According to the length of the prestressed concrete pile to be manufactured, one or a plurality of partitions are arranged inside the formwork, and the prestressed concrete pile having a length determined by the partitioning position is manufactured. Pile manufacturing method.

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