JP6795932B2 - Pile - Google Patents

Description

The present invention relates to piles.

Ready-made piles manufactured at the factory may be used for the pile foundations of buildings. Types of ready-made piles include concrete piles with outer shell steel pipes (SC piles), centrifugal prestressed reinforced concrete piles (PRC piles), and pretension type centrifugal high-strength prestressed concrete piles (PHC piles) (for example, patent documents). See 1-3).

These ready-made piles have a cylindrical pile body manufactured by centrifugal molding using high-strength concrete, but the deformation performance of the pile body when a bending moment or the like is applied is poor, and the concrete of the pile body is crushed. There is a problem that concrete pieces are peeled off inside and easily lead to brittle fracture.

Therefore, in order to improve the deformation performance of the ready-made pile, a method of providing filled concrete inside the pile body is known (see, for example, Non-Patent Document 1). The inside of the pile body is filled with filled concrete and behaved as restraint concrete, thereby preventing brittle fracture and improving deformation performance.

Japanese Unexamined Patent Publication No. 2012-162983 Japanese Unexamined Patent Publication No. 2012-224991 Japanese Patent Application Laid-Open No. 2002-309572

Takuya Nagae, Shizuo Hayashi, Keiichi Katori "Evaluation of Ultimate Performance of PRC Pile", Concrete Engineering, Vol.41, No.8,2003.8

However, the method of providing the filled concrete inside the pile body has a problem in terms of workability. That is, if the filled concrete is provided before the pile is driven at the site, the pile body may not settle during the driving. In addition, when filling concrete is provided after the pile is driven, there is a concern that the construction period will be lengthened in order to remove the soil cement inside the pile body that is generated during the pile driving. In addition, although the filled concrete is provided in the required range, its position management is difficult.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a pile having high deformation performance and easy construction.

The first invention for achieving the above-mentioned object is a hollow cylinder made of concrete, an end plate provided on an end surface of the cylinder, and a tubular outer surface provided on an outer peripheral surface of the cylinder. A reinforcing body, a tubular inner reinforcing body provided inside the tubular body, and a filler filled between the tubular body and the inner reinforcing body are provided, and the inner reinforcing body is a cylinder. It is a pile having a shaped portion and an annular flange portion, and the flange portion and the end plate are arranged and joined so as to be overlapped with each other, and the inside of the inner reinforcing body is hollow .

In the present invention, by providing the inner reinforcing body inside the cylinder and filling the filler between the cylinder and the inner reinforcing body, the restraining effect of the cylinder on the concrete can be exhibited. As a result, as in the case of providing the filled concrete as described above, the concrete of the cylinder is prevented from being crushed and the concrete pieces are prevented from peeling off inside, brittle fracture is prevented, and the deformation performance of the pile is improved. Moreover, in the present invention, since it is not necessary to provide the filling concrete inside the cylinder, the pile driving is not hindered and the construction is facilitated. In addition, the filler can absorb the unevenness of the inner peripheral surface that occurs during the manufacture of the tubular body, and the restraining effect of the inner reinforcing body can be suitably exerted.

The outer reinforcing body is arranged over the entire length of the tubular body. Alternatively, the outer reinforcing body is arranged at a portion other than the central portion in the axial direction of the tubular body.
The present invention can be applied to SC piles, PHC piles, and PRC piles. In the case of SC piles, the outer reinforcing body is arranged over the entire length of the cylinder. In the case of PRC piles and PHC piles, the outer reinforcing body is arranged in a part other than the axial central part of the cylinder.

A second invention includes a concrete cylinder, an end plate provided on the end face of the cylinder, a tubular outer reinforcing body provided on the outer peripheral surface of the cylinder, and the inside of the cylinder. The inner reinforcing body is provided with a tubular inner reinforcing body and a filler filled between the tubular body and the inner reinforcing body, and the inner reinforcing body has a tubular portion and an annular flange portion. and, the flange portion and said end plate is disposed to overlap joined, the front Symbol flange portion and the cylindrical portion, characterized in that it is joined by the small joints of strength tensile than the tubular portion It is a pile .
The inner reinforcing body is composed of a tubular portion and an annular flange portion, and by joining the flange portion and the end plate of the tubular body, the inner reinforcing body can be easily attached, and the inner reinforcing body is filled with a filler. It can also be used as a formwork for time. By joining the flange part and the tubular part of the inner reinforcing body with a joint part with a small tensile strength, when a bending moment is applied to the pile, the inner reinforcing body bears the bending moment on one side of the pile and opposes it. It is possible to prevent excessive compressive force from being applied to the concrete of the cylinder on the side.

A third invention includes a concrete cylinder, an end plate provided on the end surface of the cylinder, a tubular outer reinforcing body provided on the outer peripheral surface of the cylinder, and the inside of the cylinder. A tubular inner reinforcing body provided and a filler filled between the tubular body and the inner reinforcing body are provided, the end plate is annular, and the inner edge portion is inside the tubular body. The pile is provided so as to overhang, and the inner reinforcing body is joined to the inner edge portion of the end plate.
This makes it easier to connect the piles up and down.

According to the present invention, it is possible to provide a pile having high deformation performance and easy construction.

The figure which shows SC pile 1. The figure which shows the inner reinforcing body 9. The figure which shows the manufacturing method of SC pile 1. The figure which shows SC pile 1'. The figure which shows the bending moment M applied to SC pile 1. The figure which shows the inner reinforcing body 9a, 9a'. The figure which shows SC pile 1a. The figure which shows the PHC pile 31.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing SC pile 1 which is a pile according to the first embodiment of the present invention. FIG. 1A is a view showing a cross section of the SC pile 1 along the axial direction, and FIG. 1B is a perspective view of an end portion of the SC pile 1.

The SC pile 1 is a concrete pile (ready-made pile) with an outer shell steel pipe having a steel pipe (outer reinforcing body) 3, a tubular body 5, an end plate 7, an inner reinforcing body 9, a filler 11, and the like. The SC pile 1 is provided with an inner reinforcing body 9 and a filler 11 inside the cylinder 5 to exert a restraining effect on the concrete of the cylinder 5, thereby preventing brittle fracture and enhancing deformation performance. ..

The steel pipe 3 is a tubular reinforcing body provided so as to cover the outer peripheral surface of the tubular body 5. The steel pipe 3 is arranged over the entire length of the tubular body 5 in the axial direction.

The tubular body 5 is a substantially cylindrical pile body made of high-strength concrete, and is manufactured by centrifugal molding.

The end plate 7 is an annular plate material provided on both end faces in the axial direction of the tubular body 5, and a steel plate or the like is used. The end plate 7 and the end of the steel pipe 3 are joined by a welded portion (not shown).

The inner reinforcing body 9 is a tubular reinforcing body provided inside the tubular body 5. FIG. 2 is a perspective view showing the inner reinforcing body 9. As shown in FIG. 2, the inner reinforcing body 9 has a tubular portion 91 and a flange portion 92.

The tubular portion 91 is a substantially cylindrical member, and for example, a steel pipe is used. The flange portion 92 is an annular plate material provided so as to project outward from the end portion of the tubular portion 91, and a steel plate or the like is used.

In the present embodiment, the end portion of the tubular portion 91 and the inner edge portion of the flange portion 92 are welded by the welded portion 95, and the tubular portion 91 and the flange portion 92 are joined and integrated. The welded portion 95 is a complete penetration weld.

As shown in FIG. 1, the inner reinforcing body 9 is attached so that the flange portion 92 is arranged so as to overlap the end plate 7 and the tubular portion 91 is inserted inside the tubular body 5. The flange portion 92 is joined to the end plate 7 by welding at the welded portion 17 along the outer peripheral portion, and the tubular portion 91 has a predetermined length range from the end face of the tubular body 5 toward the central portion in the axial direction. It is provided in. Reference numeral 97 in FIG. 1A is a backing plate used when performing complete penetration welding at the welded portion 95.

The filler 11 is filled between the tubular body 5 and the inner reinforcing body 9. For example, non-shrink mortar, high-fluidity concrete, or the like is used as the filler 11. The filler 11 has a role of absorbing the unevenness generated on the inner peripheral surface of the cylinder 5 during the manufacture of the cylinder 5 and ensuring that the inner reinforcing body 9 exerts the effect of restraining the concrete of the cylinder 5. The inner reinforcing body 9 and the filler 11 are provided at both ends of the tubular body 5 in the axial direction, but may be provided only at the ends on the pile head side.

In order to manufacture the SC pile 1, first, as shown in FIG. 3A, an SC pile composed of a steel pipe 3, a cylinder 5, an end plate 7, and the like is manufactured by a conventional manufacturing method. After that, as shown in FIG. 3B, the inner reinforcing body 9 is attached to the SC pile as described above. Then, the SC pile 1 is manufactured by using the inner reinforcing body 9 as a formwork and filling the filler 11 between the tubular body 5 and the inner reinforcing body 9 as shown in FIG. 3C. To.

As described above, in the present embodiment, the inner reinforcing body 9 is provided inside the tubular body 5 of the SC pile 1, and the filler 11 is filled between the tubular body 5 and the inner reinforcing body 9, so that the tubular body 5 is formed. Can exert a restraining effect on concrete. As a result, as in the case of providing the filled concrete as described above, when a bending moment or the like is applied to the SC pile 1, the concrete of the cylinder 5 is prevented from being crushed and the concrete pieces are prevented from peeling off inside, and the brittleness is prevented. It prevents breakage and improves the deformation performance of SC pile 1.

Moreover, in the present embodiment, since it is not necessary to provide the filling concrete inside the tubular body 5, there is no problem in driving the SC pile 1 into the field, and the construction is easy. Further, the filler 11 can absorb the unevenness of the inner peripheral surface that occurs during the manufacture of the tubular body 5, and the restraining effect of the inner reinforcing body 9 can be suitably exerted. In addition, since the SC pile 1 can be manufactured only by performing an additional step after the conventional manufacturing process of the SC pile, the SC pile 1 can be manufactured by using the conventional manufacturing line as it is.

Further, the inner reinforcing body 9 is composed of a tubular portion 91 and an annular flange portion 92, and by joining the flange portion 92 and the end plate 7, the inner reinforcing body 9 can be easily attached, and the inner reinforcing body 9 can be attached. It can also be used as a mold for filling the filler 11. In the present embodiment, the end plate 7 and the flange portion 92 of the inner reinforcing body 9 are joined by the welded portion 17, but the joining method is not limited to this. As shown in the SC pile 1'in FIG. 4, the end plate 7 and the flange portion 92 of the inner reinforcing body 9 may be joined by using a bolt 25.

Hereinafter, another example of the present invention will be described as the second to fourth embodiments. Each embodiment will mainly explain points different from the embodiments described so far, and the same reference points will be omitted in the drawings and the like. In addition, the configurations described in each embodiment, including the first embodiment, can be combined as needed.

[Second Embodiment]
In the SC pile 1 described above, when a bending moment M as shown in FIG. 5 is applied to the pile head, the steel pipe 3 exerts a bending moment M on one side portion (the right portion in the example of FIG. 5) of the SC pile 1. In addition to the tensile force T generated by the burden, the tensile force T'is generated by the tubular portion 91 of the inner reinforcing body 9 bearing the bending moment M. Therefore, on the opposite side of the SC pile 1 (the left side in the example of FIG. 5), the compressive force C (= T + T') that balances the above tensile force (T + T') becomes large, and the cylinder body. May accelerate the crushing of concrete in 5.

Even if the tubular portion 91 of the inner reinforcing body 9 bears the bending moment M, such as when the concrete strength of the tubular body 5 is sufficiently high or when the thickness of the filler 11 is sufficiently thick, the concrete of the tubular body 5 It is good if it does not affect the crushing, but if the tubular portion 91 of the inner reinforcing body 9 bears the bending moment M as described above, the concrete of the tubular body 5 may be crushed earlier. The shape portion 91 and the flange portion 92 may be partially joined without being integrated as in the first embodiment, and the tensile strength of the joint portion may be lower than the tensile strength of the tubular portion 91.

For example, in the example of the inner reinforcing body 9a of FIG. 6A, a thin steel plate 93 is attached so as to straddle the tubular portion 91 and the flange portion 92 by fillet welding or the like, and the tubular portion 91 and the flange portion 92 are attached to the inner circumference. Join at the surface. A plurality of steel plates 93 are arranged at intervals along the inner peripheral surface, thereby forming a joint portion 94 between the tubular portion 91 and the flange portion 92. The tensile strength of the joint portion 94 is lower than that of the tubular portion 91 so that the joint portion 94 breaks early with respect to the tensile force T'and the tubular portion 91 of the inner reinforcing body 9a does not bear the bending moment M. By doing so, it is possible to prevent an excessive compressive force C from being generated in the concrete of the tubular body 5 and suppress its crushing.

On the other hand, in the example of the inner reinforcing body 9a'in FIG. 6B, the welded portion 96 (joint portion) of the tubular portion 91 and the flange portion 92 is partially welded. In this example, the tensile strength of the welded portion 96 depends on the throat thickness of the welded portion 96, the welding length (the length of the inner peripheral surface of the tubular portion 91 in the circumferential direction), and the welding strength (tensile strength of the weld metal, etc.). Since it is determined from (determined), it is preferable to set this tensile strength lower than that of the tubular portion 91.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 7A is a diagram showing an axial end portion of the SC pile 1a according to the third embodiment.

The SC pile 1a differs from the first embodiment in the configuration of its end. That is, in the SC pile 1a shown in FIG. 7A, the inner edge portion of the end plate 7a projects inside the tubular body 5, and the tubular portion 91 of the inner reinforcing body 9b is directly joined to the inner edge portion. The joining method is not particularly limited, and it is possible to perform complete penetration welding as in the first embodiment, joining with a steel plate as in the second embodiment, or partial penetration welding. The inner reinforcing body 9b is composed of only the tubular portion 91, and the flange portion 92 as described above is omitted.

In the present embodiment, as shown in FIG. 7B, by directly joining the end plates 7a of the SC pile 1a to each other by welding or the like, the SC pile 1a can be vertically connected and used for a long time. When the flange portion 92 of the inner reinforcing body 9 is overlapped with the end plate 7 as in the first embodiment (see FIG. 1 and the like), the flange portion 92 becomes an obstacle to joining, but in the present embodiment, this is the case. It is easy to connect the SC pile 1a up and down without any trouble.

The configuration of the end portion described above can be applied to the pile head of the SC pile 1a, and may be applied to only one end portion of the SC pile 1a or to both ends. As shown in FIG. 7 (c), between the SC piles 1a and 1a of FIG. 7 (b), the SC pile 1a having both ends having the above-described configuration is used, and the SC pile 1a is connected for a longer time. Is also possible.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is an example in which the above-mentioned inner reinforcing body is used for a PHC pile or a PRC pile which is a ready-made pile.

FIG. 8 is an example of the PHC pile 31, and is a diagram showing a cross section of the PHC pile 31 along the axial direction. The PHC pile 31 has an outer reinforcing body 33, a tubular body 35, an end plate 37, an inner reinforcing body 9, a filler 11, a tensioning material 41, and the like.

The cylinder body 35 and the end plate 37 are the same as the cylinder body 5 and the end plate 7. Further, also in this embodiment, the inner reinforcing body 9 is attached in the same manner as described above. That is, the flange portion 92 is joined to the end plate 37 by the welded portion 39, and the tubular portion 91 is inserted inside the tubular body 35. The filler 11 is also provided in the same manner as in the first embodiment.

The outer reinforcing body 33 is provided so as to cover the outer peripheral surface near the axial end portion of the tubular body 35, and is arranged at a portion other than the central portion in the axial direction of the tubular body 35. The outer reinforcing body 33 is a tubular body made of steel, for example, a steel pipe. The end portion of the outer reinforcing body 33 and the end plate 37 are joined by welding or the like.

The outer reinforcing body 33 is longer than a general reinforcing band provided on the outer peripheral surface of the PHC pile, and the length from the end surface of the tubular body 35 is longer than that of the tubular portion 91 of the inner reinforcing body 9. Is also big.

The tension material 41 is a steel material for introducing axial prestress into the tubular body 35, and a PC steel material or the like is used. The tension member 41 is embedded in the tubular body 35 along the axial direction of the tubular body 35, and its end portion is fixed to the end plate 37.

The same effect as that of the first embodiment can be obtained with the PHC pile 31 of the fourth embodiment. The same configuration can be applied to PRC piles in which axial reinforcements are embedded in the cylinder 35 in addition to the tension member 41.

Although the embodiments of the present invention have been described above with reference to the attached drawings, the technical scope of the present invention does not depend on the above-described embodiments. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical ideas described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

1, 1', 1a: SC pile 3: Steel pipe 5, 35: Cylinder body 7, 7a, 37: End plate 9, 9a, 9a', 9b: Inner reinforcing body 11: Filler 17, 39, 95, 96: Welded part 25: Bolt 31: PHC pile 33: Outer reinforcing body 41: Tension material 91: Cylindrical part 92: Flange part 93: Steel plate 94: Joint part 97: Support plate

Claims (5)

A hollow concrete body and
An end plate provided on the end face of the cylinder and
A tubular outer reinforcing body provided on the outer peripheral surface of the tubular body and
A tubular inner reinforcing body provided inside the tubular body and
A filler filled between the cylinder and the inner reinforcing body,
Equipped with
The inner reinforcing body has a tubular portion and an annular flange portion.
The flange portion and the end plate are arranged and joined so as to overlap each other.
A pile characterized in that the inside of the inner reinforcing body is hollow . The pile according to claim 1, wherein the outer reinforcing body is arranged over the entire length of the tubular body. The pile according to claim 1, wherein the outer reinforcing body is arranged at a portion other than the central portion in the axial direction of the tubular body. With a concrete cylinder
An end plate provided on the end face of the cylinder and
A tubular outer reinforcing body provided on the outer peripheral surface of the tubular body and
A tubular inner reinforcing body provided inside the tubular body and
A filler filled between the cylinder and the inner reinforcing body,
Equipped with
The inner reinforcing body has a tubular portion and an annular flange portion.
The flange portion and the end plate are arranged and joined so as to overlap each other.
It said flange portion and the cylindrical portion, you characterized in that it is joined by the small joints of strength tensile than the tubular portion pile. With a concrete cylinder
An end plate provided on the end face of the cylinder and
A tubular outer reinforcing body provided on the outer peripheral surface of the tubular body and
A tubular inner reinforcing body provided inside the tubular body and
A filler filled between the cylinder and the inner reinforcing body,
Equipped with
The end plate is annular and is provided so that the inner edge portion projects inside the cylinder.
Pile it characterized in that the inner reinforcement is joined to the inner edge of the end plate.

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