JPWO2015083807A1 - Steel pipe pile joint structure - Google Patents

Abstract

The steel pipe pile joint structure is a steel pipe pile joint structure that connects the first steel pipe pile and the second steel pipe pile coaxially, and the outer fitting valley is closer to the outer fitting step portion than the first steel pipe pile. The plate thickness of the inner fitting valley portion is made larger as the inner fitting step closer to the second steel pipe pile is formed, and the inner fitting end portion is inserted into the outer fitting end portion and relatively rotated. The total area of the tension-side contact surface in which the inner fitting front end surface and the facing surface of the inner fitting front end surface are separated by a predetermined separation distance (D) and bear a tensile force. However, it is less than or equal to the total area of the area of the front end surface of the external fitting that bears the compressive force and the total area of the compression-side contact surface that bears the compressive force.

Description

The present invention relates to a joint structure of steel pipe piles for connecting a first steel pipe pile and a second steel pipe pile in the axial direction.
This application claims priority on December 6, 2013 based on Japanese Patent Application No. 2013-252957 for which it applied to Japan, and uses the content here.

Conventionally, welded joints and mechanical joints have been used as joint structures for connecting the first steel pipe pile and the second steel pipe pile in the axial direction.
A welded joint is obtained by abutting and welding the first steel pipe pile and the second steel pipe pile at their ends. However, the joint structure by the welded joint has a difficulty in workability, and the quality and working time of the welded part greatly depend on the field environment and the skill level of the worker.

  Then, the joint structure of the steel pipe pile by a mechanical joint which is disclosed by patent document 1 and patent document 2 is proposed as a joint structure of the steel pipe pile excellent in workability.

In the joint structure of steel pipe piles disclosed in Patent Document 1, a pair of externally fitted end portions and internally fitted end portions that can be fitted to each other are formed on the first pile and the second pile adjacent to each other in the axial direction. Is done. Then, the engaging portion and the engaged portion that are engaged with each other by being relatively rotated around the axis center in a state where the inner fitting end portion is inserted into the outer fitting end portion are the outer fitting end portion and the inner fitting end. Formed in the part.
The joint structure of the steel pipe pile disclosed in Patent Document 1 is a separation preventing means for preventing the engaged engagement portion and the engaged portion from separating in the radial direction of the first pile or the second pile. Are provided at the engaging portion and the engaged portion.

In the joint structure of steel pipe piles disclosed in Patent Document 2, a pair of externally fitted end portions and internally fitted end portions that can be fitted to each other are formed on the first pile and the second pile adjacent to each other in the axial direction. Is done. Then, in a state where the inner fitting end is inserted into the outer fitting end, the engaging convex portion and the engaged convex portion that are engaged with each other by rotating around the axial center are formed between the outer fitting end portion and the inner fitting end. A plurality of end portions are formed in the axial direction.
In the joint structure of steel pipe piles disclosed in Patent Document 2, the formation position of the engagement convex portion provided on the base end side is closer to the formation portion of the engagement convex portion provided with the outer fitting end portion on the distal end side. It is formed to have a large diameter, and the inner fitting end portion is formed to have a smaller diameter than the formation portion of the engaged convex portion provided on the proximal end side as the formation portion of the engaged convex portion provided on the distal end side.

Japanese Unexamined Patent Publication No. 11-43937 Japanese Unexamined Patent Publication No. 11-43936

  In the joint structure of the steel pipe pile, it is transmitted from the proximal end side to the distal end side of the outer fitting end portion and the inner fitting end portion to the engaged portion and the engaged convex portion from the engaging convex portion. Tensile force decreases.

  However, in the steel pipe pile joint structure disclosed in Patent Document 1, the tensile force transmitted to the engaged portion decreases from the proximal end side to the distal end side of the outer fitting end portion and the inner fitting end portion. Nevertheless, the plate thickness of the engaged portion is the same in the axial direction. For this reason, especially the joint structure of the steel pipe pile disclosed by patent document 1 has a useless part in plate | board thickness at the front end side of an external fitting end part and an internal fitting end part, and plate | board thickness increases more than necessary. There was a problem that the cost increased.

  On the other hand, in the joint structure of the steel pipe pile disclosed in Patent Document 2, the tensile force transmitted to the engaged convex portion decreases from the proximal end side to the distal end side of the outer fitting end portion and the inner fitting end portion. Correspondingly, the thickness of the engaged convex portion is gradually reduced from the base end side toward the front end side. However, in the joint structure of the steel pipe pile disclosed in Patent Document 2, the plate thickness of the engaged convex portion is reduced on the distal end side of the outer fitting end portion and the inner fitting end portion, so that the outer fitting end portion and the inner fitting end portion are reduced. There is a problem in that the compressive proof stress of the engaged convex portion is reduced at the distal end side of the fitting end portion, and the engaged convex portion is buckled and deformed.

  The present invention has been devised in view of the above-described problems, and the object of the present invention is to increase the material cost by reducing the thickness of the outer fitting end portion and the distal end side of the inner fitting end portion. It is providing the joint structure of the steel pipe pile which can prevent buckling deformation of the thinnest part of the front end side while suppressing.

Aspects of the present invention are as follows.
(1) A first aspect of the present invention is a joint structure of steel pipe piles that connects the first steel pipe pile and the second steel pipe pile coaxially. The steel pipe pile joint structure is provided in the first steel pipe pile, and an outer fitting end portion in which a plurality of outer fitting step portions are formed along the extending direction of the first axis of the first steel pipe pile; An inner fitting end portion provided on the second steel pipe pile and formed with a plurality of inner fitting step portions along the extending direction of the second axis of the second steel pipe pile, and the plurality of outer fittings. Each of the stepped portions protrudes in a direction toward the first axis and a plurality of outer fitting mountain portions formed in the circumferential direction around the first axis, and each of the outer fitting mountain portions adjacent to each other. A plurality of internal fitting steps, each including an external fitting groove portion formed between the outer fitting groove portions and an outer fitting valley portion formed adjacent to each of the outer fitting mountain portions and close to the first steel pipe pile. Each of the portions protrudes in a direction away from the second axis and a plurality of internally fitted mountain portions formed in the circumferential direction around the second axis are adjacent to each other. A plurality of inner fitting groove portions formed between the fitting mountain portions, and inner fitting valley portions formed on the proximal end side adjacent to the respective inner fitting mountain portions and close to the second steel pipe pile, In the outer fitting step portion, the outer fitting step portion closer to the first steel pipe pile has a larger plate thickness of the outer fitting valley portion, and the plurality of inner fitting step portions are closer to the second steel pipe pile. The thickness of the inner fitting valley portion is increased as the inner fitting stepped portion is formed, and the inner fitting end is inserted into the outer fitting end portion and relatively rotated to be fitted. The internal fitting front end surface on the front end side of the part and the opposing surface of the internal fitting front end surface are separated by a predetermined separation distance D, and between the plurality of outer fitting stepped portions and the plurality of inner fitting stepped portions. Of the contact surfaces that contact each other, the total area of the tension side contact surfaces that bear the tensile force is the same as the area of the outer fitting front end surface of the outer fitting end that bears the compressive force and the compressive force. You Is less than or equal to the total area of the total area of the compression-side contact surface.

(2) In the joint structure of steel pipe piles according to (1) above, the total area of the tension side contact surface may be equal to or less than the total area of the compression side contact surface.
(3) In the joint structure of steel pipe piles according to (1) or (2) above, in the inner fitting mountain portion of the inner fitting step portion closest to the distal end side of the inner fitting end portion, the second axial direction When the projecting height in the direction toward H is defined as h and the length in the extending direction of the second axis is defined as l, the predetermined separation distance D may satisfy the following formula (A).
D ≧ (h ² + l ² ) ^0.5 −l Formula (A)
(4) In the steel pipe pile joint structure according to any one of (1) to (3) above, the protruding heights of the internally fitted mountain portions in the plurality of internally fitted step portions, and the plurality of At least one of the projecting heights of the outer fitting mountain portion in the outer fitting step portion may be substantially the same.
(5) In the steel pipe pile joint structure according to any one of (1) to (4), the opposing surface of the inner fitting distal end surface is an outer fitting on the proximal end side of the outer fitting end portion. It may be a base end face.
(6) In the steel pipe pile joint structure according to any one of the above (1) to (4), the facing surface of the inner fitting front end face may be an end face of the first steel pipe pile.

According to the steel pipe pile joint structure described in the above (1), in the plurality of external fitting stepped portions, the outer fitting valley portion has a larger plate thickness as the outer fitting stepped portion is closer to the first steel pipe pile. In addition, the plurality of internally fitted step portions have a configuration in which the plate thickness of the internally fitted valley portion is increased as the inner fitted step portion is closer to the second steel pipe pile. Therefore, since the plate thickness at the distal end side where the tensile force and compressive force transmitted compared to the proximal end side are small is reasonably reduced, the increase in material cost is suppressed, and at the same time, the thinnest outer fitting portion and The buckling deformation of the thinnest inner fitting can be prevented.
Furthermore, according to the joint structure of the steel pipe pile described in the above (1), the tip of the inner fitting end portion is inserted in the outer fitting end portion and is coaxially rotated and fitted. The inner fitting front end surface and the opposite surface of the inner fitting front end surface are separated by a predetermined separation distance D. Therefore, since it is possible to prevent the compressive force from the opposing surface from being transmitted to the inner fitting front end surface, it is possible to prevent buckling deformation of the thinnest inner fitting portion that is easily deformed when the compressive force is applied.
Furthermore, according to the joint structure of the steel pipe pile described in the above (1), the tension that bears the tensile force among the contact surfaces that contact each other between the plurality of external fitting stepped portions and the plurality of internal fitting stepped portions. The total area of the side abutment surface is equal to or less than the total area of the area of the front end of the external fitting end that bears the compression force and the total area of the compression side abutment that bears the compression force. . Therefore, even if the thinnest part of the outer fitting is buckled and the compressive force that can be borne by the outer fitting front end surface becomes small, the compression side abutment surface of the remaining step part resists the compressive force. be able to. For this reason, it becomes possible to hold | maintain predetermined compression strength in the whole outer fitting end part and the whole inner fitting end part.
According to the joint structure of the steel pipe pile described in (2) above, the total area of the tension side contact surface is equal to or less than the total area of the compression side contact surface. Therefore, even if the thinnest part of the outer fitting should buckle and be unable to bear the compressive force at the outer fitting end face, it resists the compressive force at the compression side contact surface of the remaining stepped part. Can do. For this reason, it becomes possible to hold | maintain predetermined compression strength more reliably in the whole outer fitting end part and the whole inner fitting end part.
According to the joint structure of steel pipe piles described in (3) above, the separation distance D is set so as to satisfy the above formula (A). Therefore, even when the joint structure of the steel pipe pile is bent and deformed, the compressive force from the facing surface is not transmitted to the inner fitting front end surface, so that the buckling of the thinnest part of the inner fitting that easily deforms when compressive force is applied. Deformation can be prevented more reliably.

According to the joint structure of steel pipe piles described in the above (4), the protruding heights of the internally fitted mountain portions in the plurality of internally fitted step portions, and the projected height of the externally fitted mountain portions in the plurality of externally fitted step portions. At least one of them is substantially the same. Therefore, the machinability of the inner fitting step and / or the outer fitting step is improved.
According to the steel pipe pile joint structure according to the above (5) or (6), the opposing surface of the inner fitting front end surface is the outer fitting base end surface on the base end side of the outer fitting end portion or the end surface of the first steel pipe pile. Structural design can be adopted.

It is a perspective view which shows the joint structure of the steel pipe pile which concerns on one Embodiment of this invention. It is a figure which shows the external fitting end part of the said joint structure, Comprising: It is sectional drawing at the time of seeing in the cross section containing an axial center. It is a figure which shows the external fitting end part of the said joint structure, Comprising: It is a cross-sectional perspective view of the principal part. It is a front view which shows the internal fitting end part of the said joint structure. It is a figure which shows the internal fitting end part of the said joint structure, Comprising: It is a cross-sectional perspective view of the principal part. It is a perspective view which shows the state which inserts an internal fitting end part in the external fitting end part of the said joint structure. It is a figure which shows the state after inserting an internal fitting end part in the outer fitting end part of the said joint structure, and making it rotate relatively, Comprising: It is the perspective view by which one part was seen by the cross section. It is a fragmentary sectional view which shows the principal part of the said joint structure. It is a fragmentary sectional view showing the 1st modification of the above-mentioned joint structure. It is a fragmentary sectional view for explaining the desirable lower limit of separation distance D of the above-mentioned joint structure. It is a fragmentary sectional view showing the 2nd modification of the above-mentioned joint structure. It is a bottom view which shows the external fitting end part of the said joint structure. It is a top view which shows the internal fitting end part of the said joint structure. It is a top view which shows the external fitting end part of the said joint structure. It is a bottom view which shows the internal fitting end part of the said joint structure. It is principal part sectional drawing which shows the tensile force which acts on the external fitting end part of the said joint structure. It is principal part sectional drawing which shows the compressive force which acts on the external fitting end part of the said joint structure. It is principal part sectional drawing which shows the tensile force which acts on the internal fitting end part of the said joint structure. It is principal part sectional drawing which shows the compressive force which acts on the internal fitting end part of the said joint structure. It is principal part sectional drawing which shows the 3rd modification of the said joint structure. It is principal part sectional drawing which shows the 4th modification of the said joint structure. It is principal part sectional drawing which shows the contact surface of the external fitting end part of the said joint structure. It is principal part sectional drawing which shows the contact surface of the internal fitting end part of the said joint structure.

Hereinafter, a steel pipe pile joint structure 7 according to an embodiment of the present invention (hereinafter, sometimes referred to as a joint structure 7 according to the present embodiment or simply a joint structure 7) will be described in detail with reference to the drawings. To do.
In the following description, the axial direction of the steel pipe pile is defined as the axial direction Y, the direction orthogonal to the axial direction Y is the axial orthogonal direction X, and the direction around the axial center of the steel pipe pile is the circumferential direction W. Sometimes called.

  The joint structure 7 according to the present embodiment includes a first steel pipe pile 1 having a first axial center and a substantially circular cross section as shown in FIG. 1 in a foundation pile or the like of a structure constructed on the ground, The second steel pipe pile 2 having a second axial center and having a substantially circular cross section is provided as a mechanical joint that connects coaxially (axial direction Y).

  An outer fitting end portion 3 in which a plurality of outer fitting step portions 4 are formed along the axial direction Y is joined to the upper end portion of the first steel pipe pile 1 by welding or the like. An inner fitting end portion 5 in which a plurality of inner fitting step portions 6 are formed along the axial direction Y is joined to the lower end portion of the second steel pipe pile 2 by welding or the like. The outer fitting end portion 3 and the inner fitting end portion 5 have a structure that can be fitted to each other.

Each of the plurality of outer fitting step portions 4 formed on the outer fitting end portion 3 protrudes in the direction toward the axis and is formed with a plurality of outer fitting mountain portions 31 formed in the circumferential direction W, and in the circumferential direction W. An outer fitting groove 32 formed between each adjacent outer fitting mountain portion 31, and an outer fitting valley portion formed adjacent to each outer fitting mountain portion 31 and close to the first steel pipe pile. 33.
In each outer fitting step part 4, the fitting groove part 32 and the fitting valley part 33 are formed with the same plate thickness so as to be flush with each other as shown in FIG. From the viewpoint of
In the joint structure 7 according to the present embodiment, as shown in FIG. 1, four outer fitting mountain portions 31 are formed at predetermined intervals in the circumferential direction W with respect to each of the plurality of outer fitting step portions 4. The present invention is not limited to this structure.

Each of the plurality of inner fitting stepped portions 6 formed in the inner fitting end portion 5 protrudes in a direction away from the axial center and has a plurality of inner fitting mountain portions 51 formed in the circumferential direction W, and in the circumferential direction W. Internal fitting groove portions 52 formed between the respective internal fitting mountain portions 51 adjacent to each other, and an internal fitting valley formed on the proximal end side adjacent to each internal fitting mountain portion 51 and close to the second steel pipe pile. Part 53.
In each internal fitting step part 6, the internal fitting groove part 52 and the internal fitting valley part 53 are formed with the same plate thickness so as to be flush with each other, as shown in FIG. From the viewpoint of
In the joint structure 7 according to the present embodiment, as shown in FIG. 1, four inner fitting mountain portions 51 are formed at predetermined intervals in the circumferential direction W with respect to each of the plurality of inner fitting step portions 6. The present invention is not limited to this structure.

  Further, in the joint structure 7 according to the present embodiment, as shown in FIG. 1, a rotation inhibiting key for inhibiting relative rotation after fitting between the outer fitting end portion 3 and the inner fitting end portion 5 is inserted. Although four key grooves P are formed in the circumferential direction W, the key grooves need not be formed.

  In the joint structure 7 according to the present embodiment, as shown in FIG. 2, the four external fitting step portions 4 are formed in the axial direction Y of the external fitting end portion 3. That is, the outer fitting end portion 3 includes the first outer fitting step portion 41, the second outer fitting step portion 42, and the third outer fitting in order from the distal end side to the proximal end side in the axial direction Y of the outer fitting end portion 3. A step portion 43 and a fourth outer fitting step portion 44 are provided.

In each outer fitting step part 4, the thickness of the outer fitting groove part 32 is made smaller than the thickness of the outer fitting mountain part 31, and the outer fitting mountain part 31 and the outer fitting groove part 32 are alternately formed in the circumferential direction W. The And the external fitting peak part 31 of the some external fitting step part 4 is arrange | positioned in the axial direction Y at substantially one line.
Similarly, in each external fitting step part 4, the plate thickness of the external fitting valley part 33 is made smaller than the plate thickness of the external fitting mountain part 31, and the external fitting mountain part 31 and the external fitting valley part 33 are axial directions. Alternatingly formed with Y.

As shown in FIG. 3, the plate thickness of the external fitting valley portion 33 is formed to be larger as the external fitting step portion 4 is closer to the proximal end side of the external fitting end portion 3.
That is, the plate thickness of the external fitting valley portion 33 of the first external fitting step portion 41 is smaller than the plate thickness of the external fitting valley portion 33 of the second external fitting step portion 42, and the external fitting of the second external fitting step portion 42 is performed. The plate thickness of the valley portion 33 is smaller than the plate thickness of the external fitting valley portion 33 of the third external fitting step portion 43, and the plate thickness of the external fitting valley portion 33 of the third external fitting step portion 43 is the fourth external fitting. It is formed smaller than the plate thickness of the externally fitting valley portion 33 of the step portion 44.

The outer fitting valley portion 33 of the first outer fitting step portion 41 is formed as the outer fitting thinnest portion 30 having the smallest plate thickness among the outer fitting end portions 3, and the outer fitting mountain portion of the first outer fitting step portion 41. An outer fitting front end surface 34 is formed in a substantially flat shape on the front end side in the axial direction Y of 31.
Further, an extra fitting extra length portion 45 is formed on the proximal end side in the axial direction Y of the outer fitting valley portion 33 of the fourth outer fitting step portion 44. An outer fitting base end face 35 is formed over the entire circumference at the distal end side of the outer fitting extra length portion 45.

  In the joint structure 7 according to the present embodiment, as shown in FIG. 4, four steps of internal fitting step portions 6 are formed in the axial direction Y of the internal fitting end portion 5. That is, the inner fitting end portion 5 includes the first inner fitting step portion 61, the second inner fitting step portion 62, and the third inner fitting portion in order from the distal end side to the proximal end side in the axial direction Y of the inner fitting end portion 5. A step portion 63 and a fourth internal fitting step portion 64 are provided.

In each internal fitting step portion 6, the thickness of the internal fitting groove portion 52 is made smaller than the thickness of the internal fitting mountain portion 51, and the internal fitting mountain portions 51 and the internal fitting groove portions 52 are alternately formed in the circumferential direction W. The And the internal fitting mountain part 51 of the some internal fitting step part 6 is arrange | positioned in the axial direction Y at a substantially line.
Similarly, in each internal fitting step part 6, the plate thickness of the internal fitting valley part 53 is made smaller than the plate thickness of the internal fitting mountain part 51, and the internal fitting mountain part 51 and the internal fitting valley part 53 are axial direction. Alternatingly formed with Y.

As shown in FIG. 5, the plate thickness of the internal fitting valley portion 53 is formed to be larger as the internal fitting step portion closer to the proximal end side of the internal fitting end portion 5.
That is, the plate thickness of the internal fitting valley portion 53 of the first internal fitting step portion 61 is smaller than the plate thickness of the internal fitting valley portion 53 of the second internal fitting step portion 62, and the internal fitting of the second internal fitting step portion 62. The plate thickness of the valley portion 53 is smaller than the plate thickness of the internal fitting valley portion 53 of the third internal fitting step portion 63, and the plate thickness of the internal fitting valley portion 53 of the third internal fitting step portion 63 is the fourth internal fitting. It is formed smaller than the plate thickness of the internal fitting valley portion 53 of the step portion 64.

The inner fitting valley portion 53 of the first inner fitting step portion 61 is formed as the inner fitting thinnest portion 50 having the smallest plate thickness among the inner fitting end portions 5, and the inner fitting mountain portion of the first inner fitting step portion 61. An inner fitting front end face 54 is formed in a substantially flat shape on the front end side in the axial direction Y of 51.
Further, an inner fitting surplus length portion 65 is formed on the proximal end side in the axial direction Y of the inner fitting valley portion 53 of the fourth inner fitting step portion 64. An inner fitting base end face 55 is formed over the entire circumference on the distal end side of the inner fitting surplus length portion 65.

  In the joint structure 7 according to the present embodiment, in order to connect the first steel pipe pile 1 and the second steel pipe pile 2 coaxially, as shown in FIGS. 6 and 7, an outer fitting end portion 3 and an inner fitting end portion are provided. 5 are fitted to each other. FIG. 7 is a perspective view showing a state in which a part of the external fitting end 3 is cut.

  Specifically, first, as shown in FIG. 6, the inner fitting end portion 5 attached to the second steel pipe pile 2 is inserted into the outer fitting end portion 3 attached to the first steel pipe pile 1. In each inner fitting step part 6, the height of the inner fitting mountain part 51 in the axial center orthogonal direction X is set to be equal to or less than the depth of the outer fitting groove part 32 corresponding to the fitting time in the axial center orthogonal direction X. As a result, the inner fitting mountain portion 51 can pass through the outer fitting groove portion 32.

  Next, as shown in FIG. 7, the first steel pipe pile 1 and the second steel pipe pile 2 are relatively rotated in the circumferential direction W around the axis center with the inner fitting end 5 inserted into the outer fitting end 3. Let In each inner fitting step portion 6, the depth of the inner fitting valley portion 53 in the axial center orthogonal direction X is designed to be greater than the height of the outer fitting mountain portion 31 corresponding to the fitting in the axial center orthogonal direction X. Thereby, it becomes a structure which can fit the external fitting mountain part 31 to the internal fitting trough part 53. FIG.

  FIG. 8 is a schematic cross-sectional view of a state in which the inner fitting end portion 5 of the joint structure 7 according to the present embodiment is inserted into the outer fitting end portion 3 and is relatively rotated. As shown in FIG. 8, the joint structure 7 has an outer fitting in which an outer fitting distal end surface 34 on the distal end side of the outer fitting end portion 3 and an inner fitting proximal end surface 55 on the proximal end side of the inner fitting end portion 5 face each other. It has the opposing part 36, the internal fitting front end surface 54 of the front end side of the internal fitting end part 5, and the internal fitting opposing part 56 which the external fitting base end surface 35 of the base end side of the external fitting end part 3 opposes.

  As shown in FIG. 8, the outer fitting step portion 4 (the first outer fitting step portion 41, the second outer fitting step portion 42, the third outer fitting step portion 43) excluding the fourth outer fitting step portion 44 and the first inner portion. In the inner fitting step portion 6 (fourth inner fitting step portion 64, third inner fitting step portion 63, second inner fitting step portion 62) excluding the fitting step portion 61, the length of the inner fitting mountain portion 51 in the axial direction Y The length of the external fitting valley portion 33 corresponding to the fitting time in the axial direction Y is designed to be substantially the same as the length of the external fitting mountain portion 31 in the axial direction Y. It is designed to be approximately equal to the length of the fitting valley portion 53 in the axial direction Y. Thereby, it is possible to engage the outer fitting mountain portion 31 and the inner fitting mountain portion 51 in the axial direction Y.

  On the other hand, in the fourth outer fitting step portion 44 and the first inner fitting step portion 61, the length in the axial direction Y of the inner fitting mountain portion 51 is the axial center of the outer fitting valley portion 33, as shown in FIG. It is designed to be smaller than the length in the direction Y. As a result, the inner fitting front end surface 54 and the outer fitting base end surface 35 which is the opposite surface are separated by a predetermined separation distance D (mm) at the inner fitting facing portion 56, and the inner fitting facing portion 56 is separated from the inner fitting facing portion 56. An internal fitting gap 57 is formed.

FIG. 9 is a schematic cross-sectional view showing a steel pipe pile joint structure 107 according to a first modification of the present invention. In this joint structure 107, the plate thickness of the external fitting extra length portion 45 is set to be equal to the plate thickness of the external fitting valley portion 33 of the fourth external fitting step portion 44. According to this structure, it is possible to reduce the material cost of the external fitting end portion 3, improve the machinability of the external fitting valley portion 33, and reduce the manufacturing cost of the external fitting end portion 3.
In the case of this joint structure 107, the facing surface of the inner fitting front end surface 54 is the end surface of the first steel pipe pile 1. Therefore, when the inner fitting front end surface 54 and the end surface of the first steel pipe pile 1 which is the opposite surface are separated by a predetermined separation distance D (mm) in the inner fitting facing portion 56, An internal fitting gap 157 is formed.

  By forming the internal fitting gaps 57 and 157, it is possible to avoid the transmission of the compressive force in the axial direction Y to the internal fitting front end surface 54. Accordingly, it is possible to prevent buckling deformation of the innermost fitting thinnest portion 50.

  The separation distance D (mm) between the internal fitting gaps 57 and 157 may be more than 0 mm. However, in order to avoid the compressive force in the axial direction Y being transmitted to the internally fitted front end surface 54 even when the steel pipe pile is bent and deformed, the separation distance D (mm) is expressed by the following formula (1). It is preferable to set so as to satisfy.

D ≧ (h ² + l ² ) ^0.5 −l Equation (1)

h (mm): Projection height in the direction toward the axial center of the internal fitting step at the internal fitting step closest to the distal end side of the internal fitting end 1 (mm): closest to the distal end side of the internal fitting end Length in the extending direction of the axial center of the internal fitting peak at the internal fitting step

As shown in FIG. 10, the above formula (1) is a formula derived on the assumption of bending deformation in which the connection point between the thinnest inner fitting portion 50 and the inner fitting mountain portion 51 is the bending center point C.
That is, by setting the separation distance D (mm) so as to satisfy the above formula (1), it is ensured that the inner fitting front end surface 54 comes into contact with the facing surface even when the steel pipe pile is bent and deformed. It can be avoided.

  FIG. 11 is a cross-sectional view of an essential part showing a joint structure 207 according to a second modification of the present invention. In this joint structure 207, the outer fitting gap 37 is formed in the outer fitting facing portion 36 as well as the inner fitting facing portion 56. According to this structure, it is possible to avoid transmission of the compressive force in the axial direction Y to the outer fitting front end surface 34, and it is possible to prevent buckling deformation of the outer fitting thinnest portion 30. . Although illustration is omitted, the plate thickness of the internal fitting excess length portion 65 may be set to be equal to the plate thickness of the internal fitting valley portion 53 of the fourth internal fitting step portion 64. In that case, the opposing surface of the outer fitting front end surface 34 is the end surface of the second steel pipe pile 2. Further, the separation distance D ′ (mm) of the external fitting gap 37 may be more than 0 mm, and may be set so as to satisfy the following formula (2).

D ′ ≧ (h ′ ² + l ′ ² ) ^0.5 −l ′ (2)

h ′ (mm): Projection height in the direction toward the axis of the external fitting step at the external fitting step portion closest to the distal end side of the external fitting end portion l ′ (mm): on the distal end side of the external fitting end portion The length in the extending direction of the shaft center of the outer fitting peak at the nearest outer fitting step

  However, the inner fitting facing portion 56 side is more likely to be buckled and deformed when the compressive force is applied due to the eccentricity from the steel pipe portion than the outer fitting facing portion 36 side. Therefore, the buckling deformation preventing effect obtained by providing the outer fitting gap 37 is smaller than the buckling deformation preventing effect obtained by providing the inner fitting gap 57.

Next, the contact surface 8 of the joint structure 7 according to this embodiment will be described.
In the joint structure 7 according to the present embodiment, the inner fitting end portion 5 is inserted into the outer fitting end portion 3 and is relatively rotated, so that the outer fitting step portion 4 and the inner fitting step portion 6 have an outer fitting mountain portion. A contact surface 8 is formed in which 31 and the internally fitted mountain portion 51 are in contact with each other in the axial direction Y.

  In a state where the first steel pipe pile 1 and the second steel pipe pile 2 are connected, the first steel pipe pile 1 and the second steel pipe pile 2 are pulled in the axial direction Y from the outer fitting end 3 and the inner fitting end 5. When the force and the compressive force are applied, the outer fitting mountain portion 31 and the inner fitting mountain portion 51 resist the tensile force and the compressive force acting in the axial direction Y at the contact surface 8 in the axial direction Y. .

  In the joint structure 7 according to the present embodiment, as shown in FIGS. 12A and 12B, the outer fitting mountain portion 31 and the inner fitting mountain portion 51 come into contact with each other in each of the outer fitting step portion 4 and the inner fitting step portion 6. Among the contact surfaces 8 to be applied, the proximal end side of the outer fitting end portion 3 and the proximal end side of the inner fitting end portion 5 are tensile side contact surfaces 81 that bear a tensile force.

  Then, as shown in FIGS. 12A and 12B, the outer fitting mountain portion 31 of the first outer fitting step portion 41 and the inner fitting mountain portion 51 of the fourth inner fitting step portion 64 are pulled by the pull side contact surface 81. The outer fitting mountain portion 31 of the second outer fitting step portion 42 and the inner fitting mountain portion 51 of the third inner fitting step portion 63 have a tensile area At2 at the tension side contact surface 81, and have an area At1. The outer fitting mountain portion 31 of the third outer fitting step portion 43 and the inner fitting mountain portion 51 of the second inner fitting step portion 62 have a tensile area At3 at the tension-side contact surface 81, and the fourth outer fitting step portion. The outer fitting mountain portion 31 of 44 and the inner fitting mountain portion 51 of the first inner fitting step portion 61 have a tensile area At 4 on the tensile-side contact surface 81.

  Moreover, in the joint structure 7 which concerns on this embodiment, as shown to FIG. 13A and FIG. 13B, in each outer fitting step part 4 and each inner fitting step part 6, the outer fitting mountain part 31 and the inner fitting mountain part 51 mutually mutually. Among the contact surfaces 8 to be contacted, the distal end side of the outer fitting end portion 3 and the distal end side of the inner fitting end portion 5 are compression side abutting surfaces 86 that bear a compressive force.

  Then, as shown in FIGS. 13A and 13B, the outer fitting mountain portion 31 of the second outer fitting step portion 42 and the inner fitting mountain portion 51 of the fourth inner fitting step portion 64 are compressed by the compression side contact surface 86. The outer fitting mountain portion 31 of the third outer fitting step portion 43 and the inner fitting mountain portion 51 of the third inner fitting step portion 63 have a compression area Ac2 at the compression side abutment surface 86. The outer fitting mountain portion 31 of the fourth outer fitting step portion 44 and the inner fitting mountain portion 51 of the second inner fitting step portion 62 have a compression area Ac3 at the compression side contact surface 86.

In the joint structure 7 according to the present embodiment, the outer fitting front end face 34 and the inner fitting base end face 55 are brought into contact with each other at the outer fitting facing portion 36, while the inner fitting front end face 54 and the outer fitting base end 55 are brought into contact with each other. It has a structure in which the end face 35 is not brought into contact.
Therefore, in the joint structure 7 according to the present embodiment,
(A) The tensile force acting in the axial direction Y is resisted only by the four tensile side contact surfaces 81 where the outer fitting mountain portion 31 and the inner fitting mountain portion 51 are in contact with each other,
(B) For the compressive force acting in the axial direction Y, the outer fitting front end surface 34 on the front end side of the outer fitting end portion 3 and the outer fitting mountain portion 31 and the inner fitting mountain portion 51 abut each other. Only the three compression-side contact surfaces 86 are resisted.

In addition, as in the joint structure 207 (FIG. 11) according to the second modified example described above, the outer fitting facing portion 36 has a structure in which the outer fitting gap 37 is formed as in the inner fitting facing portion 56. In the joint structure 207,
(A ′) The tensile force acting in the axial direction Y is resisted only by the four tension side contact surfaces 81 where the outer fitting mountain portion 31 and the inner fitting mountain portion 51 are in contact with each other,
(B ′) The compression force acting in the axial direction Y is resisted only by the three compression side contact surfaces 86 on which the outer fitting mountain portion 31 and the inner fitting mountain portion 51 are in contact with each other.

  The total area (At1 + At2 + At3 + At4) of the tension side abutment surface 81 that bears the tensile force among the abutment surfaces 8 that are in contact with each other between the outer fitting stepped portion 4 and the inner fitting stepped portion 6 is an outer portion that bears the compressive force. Formed to be equal to or less than the total area of the fitting tip surface 34 (0 in the case of the joint structure 207 according to the second modification) and the total area (Ac1 + Ac2 + Ac3) of the compression-side contact surface 86 bearing the compressive force. Is done.

  In addition, the total area (At1 + At2 + At3 + At4) of the tension side abutment surface 81 that bears the tensile force among the abutment surfaces 8 that are in contact with each other between the outer fitting stepped portion 4 and the inner fitting stepped portion 6 bears the compressive force. The compression-side contact surface 86 is preferably formed to have a total area (Ac1 + Ac2 + Ac3) or less.

  Thus, in the joint structure 7 according to the present embodiment, the number of steps on which the compression-side contact surface 86 is formed is smaller than the number of steps on which the tension-side contact surface 81 is formed. Each of the outer fitting ridge portions 31 and the total fitting area 31 is set so that the total area of the abutting surface 81 is equal to or less than the total area of the outer fitting front end surface 34 that bears the compressive force and the total area of the compression side abutting surface 86. A contact surface 8 is formed on which the internal fitting mountain portions 51 are in contact with each other.

  In addition, when the key groove P for inserting the rotation suppression key for suppressing the relative rotation after fitting of the outer fitting end portion 3 and the inner fitting end portion 5 is formed on the outer fitting front end surface 34, “ The “area of the outer fitting front end surface 34 that bears the compressive force” does not include the area of the portion where the key groove is formed. This is because the rotation suppression key basically does not bear the compression force.

In the joint structure 7 according to the present embodiment, the total area of the outer fitting front end surface 34 that bears the compressive force and the total area of the compression side contact surface 86 is equal to or greater than the total area of the tension side contact surface 81. Thus, against the compression force acting in the axial direction Y with a magnitude equal to or greater than the tensile force, the outer fitting front end surface and the compression-side contact surface of each outer fitting mountain portion 31 and inner fitting mountain portion 51 Only 86 can resist.
Further, when the total area of the compression-side contact surface 86 is equal to or greater than the total area of the tension-side contact surface 81, the compression force acting in the axial direction Y with a magnitude equal to or greater than the tensile force. Resistance can be achieved only by the compression-side contact surface 86 of each of the outer fitting mountain portion 31 and the inner fitting mountain portion 51.

  In the joint structure 7 according to this embodiment, even if the outer fitting front end surface 34 and the inner fitting base end surface 55 are in contact with each other by the outer fitting facing portion 36, the outer fitting mountain of the first outer fitting step portion 41 is used. Since the compressive force does not substantially act on the portion 31, it is not necessary to consider the compressive force acting on the external fitting mountain portion 31 of the first external fitting step portion 41 in design.

In FIG. 14, the tensile force transmitted in the external fitting end part 3 of the joint structure 7 which concerns on this embodiment is shown.
A tensile force acting on the outer fitting mountain portion 31 of the first outer fitting step portion 41 is transmitted to the outer fitting valley portion 33 of the first outer fitting step portion 41. Tensile force acting on the first outer fitting step portion 41 and the outer fitting mountain portion 31 of the second outer fitting step portion 42 is transmitted to the outer fitting valley portion 33 of the second outer fitting step portion 42 together. . The outer fitting valley portion 33 of the third outer fitting step portion 43 acts on the first outer fitting step portion 41, the second outer fitting step portion 42, and the outer fitting mountain portion 31 of the third outer fitting step portion 43. The tensile force is transmitted together. The outer fitting valley portion 33 of the fourth outer fitting step portion 44 includes a first outer fitting step portion 41, a second outer fitting step portion 42, a third outer fitting step portion 43, and a fourth outer fitting step portion 44. The tensile force acting on the outer fitting mountain portion 31 is transmitted together.

Similarly, in FIG. 15, the compressive force transmitted in the external fitting end part 3 of the joint structure 7 which concerns on this embodiment is shown.
A compression force acting on the outer fitting mountain portion 31 of the second outer fitting step portion 42 is transmitted to the outer fitting valley portion 33 of the second outer fitting step portion 42. A compression force acting on the second outer fitting step portion 42 and the outer fitting mountain portion 31 of the third outer fitting step portion 43 is transmitted to the outer fitting valley portion 33 of the third outer fitting step portion 43 together. . The outer fitting valley portion 33 of the fourth outer fitting step portion 44 acts on the second outer fitting step portion 42, the third outer fitting step portion 43, and the outer fitting mountain portion 31 of the fourth outer fitting step portion 44. The compressive force is combined and transmitted.

  Thus, in the joint structure 7 according to the present embodiment, the tensile force and the compressive force transmitted from the external fitting mountain portion 31 to the external fitting valley portion 33 from the proximal end side to the distal end side of the external fitting end portion 3. Therefore, even if the thickness of the external fitting valley portion 33 is reduced on the distal end side of the external fitting end portion 3, it is possible to resist these tensile and compressive forces. Thereby, by reducing the plate thickness of the external fitting valley portion 33 from the base end side to the distal end side of the external fitting end portion 3, and suppressing the increase in the plate thickness of the entire external fitting end portion 3, the material An increase in cost can be suppressed.

  In the joint structure 7 according to the present embodiment, the plate thickness of the outer fitting valley portion 33 is reduced at the first outer fitting step portion 41 on the distal end side of the outer fitting end portion 3, and the material cost of the outer fitting end portion 3 is increased. And at the same time, the compression force is not substantially applied to the outer fitting mountain portion 31 of the first outer fitting step portion 41, so that the compression force is substantially applied to the outer fitting valley portion 33 in the first outer fitting step portion 41. Therefore, the buckling deformation of the thinnest outer fitting portion 30 can be prevented.

  Further, in the joint structure 7 according to the present embodiment, even if a compressive force acts on the outer fitting mountain portion 31 of the first outer fitting step portion 41, the compressive strength is applied to the outer fitting valley portion 33 of the first outer fitting step portion 41. Do not expect. For this reason, the joint structure 7 has the second outer fitting step even when the outer fitting thinnest portion 30 is buckled and deformed by the compressive force transmitted to the outer fitting valley portion 33 of the first outer fitting step portion 41. Since the compression force can be resisted by the external fitting valley portion 33 of the part 42, the third external fitting step portion 43, and the fourth external fitting step portion 44, the entire external fitting end portion 3 can maintain a predetermined compression strength. Is possible.

In FIG. 16, the tensile force transmitted in the internal fitting end part 5 of the joint structure 7 which concerns on this embodiment is shown.
A tensile force acting on the inner fitting mountain portion 51 of the first inner fitting step portion 61 is transmitted to the inner fitting valley portion 53 of the first inner fitting step portion 61. Tensile forces acting on the first internal fitting step portion 61 and the internal fitting mountain portion 51 of the second internal fitting step portion 62 are transmitted together to the internal fitting valley portion 53 of the second internal fitting step portion 62. The inner fitting valley portion 53 of the third inner fitting step portion 63 acts on the first inner fitting step portion 61, the second inner fitting step portion 62, and the inner fitting mountain portion 51 of the third inner fitting step portion 63. The tensile force is transmitted together. The inner trough 53 of the fourth inner step 64 has a first inner step 61, a second inner step 62, a third inner step 63, and a fourth inner step 64. The tensile force acting on the inner fitting mountain portion 51 is transmitted together.

Similarly, in FIG. 17, the compressive force transmitted in the internal fitting end part 5 of the joint structure 7 which concerns on this embodiment is shown.
A compression force acting on the inner fitting mountain portion 51 of the second inner fitting step portion 62 is transmitted to the inner fitting valley portion 53 of the second inner fitting step portion 62. The compressive force acting on the second internal fitting step portion 62 and the internal fitting mountain portion 51 of the third internal fitting step portion 63 is transmitted to the internal fitting valley portion 53 of the third internal fitting step portion 63 together. . The inner fitting valley portion 53 of the fourth inner fitting step portion 64 acts on the second inner fitting step portion 62, the third inner fitting step portion 63, and the inner fitting mountain portion 51 of the fourth inner fitting step portion 64. The compressive force is combined and transmitted.

  Thus, in the joint structure 7 according to the present embodiment, the tensile force and the compressive force transmitted from the inner fitting mountain portion 51 to the inner fitting valley portion 53 from the proximal end side to the distal end side of the inner fitting end portion 5. Therefore, even if the thickness of the inner fitting valley portion 53 is reduced on the distal end side of the inner fitting end portion 5, it is possible to resist these tensile force and compression force. Thereby, the joint structure 7 reduces the plate | board thickness of the internal fitting trough part 53 toward the front end side from the base end side of the internal fitting end part 5, and suppresses the increase in the board thickness of the internal fitting end part 5 whole. By doing so, it is possible to suppress an increase in material cost.

  The joint structure 7 reduces the plate thickness of the inner fitting valley portion 53 at the first inner fitting step portion 61 on the distal end side of the inner fitting end portion 5 and suppresses an increase in material cost of the inner fitting end portion 5. The compression force is not transmitted to the internal fitting valley portion 53 in the first internal fitting step portion 61 because the internal fitting gap 57 prevents the compression force from acting on the internal fitting mountain portion 51 of the first internal fitting step portion 61. Thus, it is possible to prevent buckling deformation of the thinnest inner fitting portion 50.

  FIG. 18A shows a joint structure 307 according to a third modification of the present invention. Like this joint structure 307, a part or all of the plurality of outer fitting stepped portions 4 and inner fitting stepped portions 6 are tapered on the side surfaces in the direction orthogonal to the axial center X of the outer fitting valley portion 33 and the inner fitting mountain portion 51. It may be provided.

  FIG. 18B shows a joint structure 407 according to a fourth modification of the present invention. As in the joint structure 407, a part or all of the plurality of outer fitting stepped portions 4 and the inner fitting stepped portion 6 are tapered on the side surfaces in the axial orthogonal direction X of the inner fitting valley portion 53 and the outer fitting mountain portion 31. It may be provided.

In the joint structure 7 according to the present embodiment, as shown in FIG. 19, the external fitting mountain portions 31 of the respective external fitting step portions 4 are axially centered from the distal end side to the proximal end side of the external fitting end portion 3. It is arranged inside the orthogonal direction X.
In the joint structure 7 according to the present embodiment, a radius r41 from the central axis to the external fitting mountain portion 31 of the first external fitting step portion 41, and a radius from the central axis to the external fitting mountain portion 31 of the second external fitting step portion 42. When r42 is defined as a radius r43 from the central axis to the external fitting mountain portion 31 of the third external fitting stepped portion 43, and a radius r44 from the central axis to the external fitting mountain portion 31 of the fourth external fitting stepped portion 44, r41 The relationship of>r42>r43> r44 is satisfied.

  Furthermore, in the joint structure 7 according to the present embodiment, as shown in FIG. 19, the height of the base end side of the outer fitting end portion 3 at the outer fitting mountain portion 31 of the first outer fitting step portion 41 is set to ht1, The height of the base end side of the external fitting end portion 3 at the external fitting mountain portion 31 of the external fitting step portion 42 is ht2, and the base end side of the external fitting end portion 3 at the external fitting mountain portion 31 of the third external fitting step portion 43. Is defined as ht3, and the height of the base end side of the outer fitting end portion 3 is defined as ht4 in the outer fitting mountain portion 31 of the fourth outer fitting step portion 44, the relationship of ht1 ≦ ht2 ≦ ht3 ≦ ht4 is established. It is filled.

  Here, the heights of the external fitting mountain portions 31 may be set to be substantially the same so that the relationship of ht1 = ht2 = ht3 = ht4 is satisfied. In this case, it is preferable from the viewpoint of the cutting workability of the external fitting mountain portion 31.

  Further, following the relationship of r41> r42> r43> r44, the height of the external fitting mountain portion 31 is set so that the relationship of ht1 <ht2 <ht3 <ht4 is satisfied, so that each external fitting step In the external fitting mountain portion 31 of the portion 4, the tensile area At1, the tensile area At2, the tensile area At3, and the tensile area At4 may be substantially the same.

  Similarly, in the joint structure 7 according to the present embodiment, as shown in FIG. 19, the height of the front end side of the outer fitting end portion 3 at the outer fitting mountain portion 31 of the second outer fitting step portion 42 is hc1, third. The height of the base end side of the outer fitting end portion 3 is hc2 at the outer fitting mountain portion 31 of the outer fitting step portion 43, and the base end side of the outer fitting end portion 3 at the outer fitting mountain portion 31 of the fourth outer fitting step portion 44. Is defined as hc3, the relationship of hc1 ≦ hc2 ≦ hc3 is satisfied.

  Here, the height of the external fitting mountain portion 31 may be set to be substantially the same so that the relationship of hc1 = hc2 = hc3 is satisfied. In this case, it is preferable from the viewpoint of the cutting workability of the external fitting mountain portion 31.

  In addition, following the relationship of r41> r42> r43> r44, the height of the outer fitting mountain portion 31 is set so that the relationship of hc1 <hc2 <hc3 is satisfied, so that each outer fitting step portion 4 is set. In the outer fitting mountain portion 31, the compression area Ac1, the compression area Ac2, and the compression area Ac3 may be substantially the same.

In the joint structure 7 according to the present embodiment, as shown in FIG. 20, the inner fitting mountain portions 51 of the respective inner fitting step portions 6 are axially centered from the distal end side to the proximal end side of the inner fitting end portion 5. It is arranged outside the orthogonal direction X.
In the joint structure 7 according to the present embodiment, a radius r61 from the central axis to the internal fitting mountain portion 51 of the first internal fitting step portion 61, and a radius from the central axis to the internal fitting mountain portion 51 of the second internal fitting step portion 62. When r62 is defined as a radius r63 from the central axis to the internal fitting mountain portion 51 of the third internal fitting step portion 63, and a radius r64 from the central axis to the internal fitting mountain portion 51 of the fourth internal fitting step portion 64, r61 The relationship <r62 <r63 <r64 is satisfied.

  Furthermore, in the joint structure 7 according to the present embodiment, as shown in FIG. 20, the height of the base end side of the inner fitting end portion 5 at the inner fitting mountain portion 51 of the fourth inner fitting step portion 64 is set to ht1, The height of the base end side of the internal fitting end portion 5 at the internal fitting mountain portion 51 of the internal fitting step portion 63 is ht2, and the base end side of the internal fitting end portion 5 at the internal fitting mountain portion 51 of the second internal fitting step portion 62. Is defined as ht3, and the height of the base end side of the inner fitting end portion 5 is defined as ht4 in the inner fitting mountain portion 51 of the first inner fitting step portion 61, the relationship of ht1 ≧ ht2 ≧ ht3 ≧ ht4 is established. It is filled.

Here, the height of the inner fitting mountain portion 51 may be set to be substantially the same so that the relationship of ht1 = ht2 = ht3 = ht4 is satisfied. In this case, it is preferable from the viewpoint of the cutting workability of the internal fitting mountain portion 51.

  Further, following the relationship of r61 <r62 <r63 <r64, by setting the height of the internal fitting mountain portion 51 so that the relationship of ht1 <ht2 <ht3 <ht4 is satisfied, each internal fitting step In the internal fitting mountain part 51 of the part 6, the tensile area At1, the tensile area At2, the tensile area At3, and the tensile area At4 may be substantially the same.

  Similarly, in the joint structure 7 according to the present embodiment, as shown in FIG. 20, the height of the tip end side of the inner fitting end portion 5 at the inner fitting mountain portion 51 of the fourth inner fitting step portion 64 is hc1, third. The height of the base end side of the internal fitting end portion 5 at the internal fitting mountain portion 51 of the internal fitting step portion 63 is hc2, and the base end side of the internal fitting end portion 5 at the internal fitting mountain portion 51 of the second internal fitting step portion 62. Is defined as hc3, the relationship of hc1 ≧ hc2 ≧ hc3 is satisfied.

  Here, the heights of the internal fitting mountain portions 51 may be set substantially the same so that the relationship of hc1 = hc2 = hc3 is satisfied. In this case, it is preferable from the viewpoint of the cutting workability of the internal fitting mountain portion 51.

  Further, following the relationship of r61 <r62 <r63 <r64, the height of the inner fitting mountain portion 51 is set so that the relationship of hc1 <hc2 <hc3 is satisfied, whereby each inner fitting step portion 6 is set. In the inner fitting mountain portion 51, the compression area Ac1, the compression area Ac2, and the compression area Ac3 may be substantially the same.

When the tensile area At1, the tensile area At2, the tensile area At3, and the tensile area At4 are set to be substantially the same, the external fitting step 4 and the internal fitting step are respectively applied to the tensile force acting in the axial direction Y. In the outer fitting mountain part 31 and the inner fitting mountain part 51 of the part 6, it can resist substantially equally.
In addition, the compression area Ac1, the compression area Ac2, and the compression area Ac3 are set to be substantially the same, so that the outer fitting step part 4 and the inner fitting step part 6 have a compressive force acting in the axial direction Y. In the external fitting mountain part 31 and the internal fitting mountain part 51, it can resist substantially equally.
As a result, the joint structure 7 can be applied to the outer fitting step portion 4 and the inner fitting step portion 51 of the inner fitting step portion 6 and the inner fitting step portion 51 with respect to the tensile force and compression force acting in the axial direction Y. Since it can resist substantially evenly, it is possible to reduce the waste in structural strength of the outer fitting end portion 3 and the inner fitting end portion 5 and facilitate the structural calculation for the tensile force and the compressive force. .

In the joint structure 7 according to the present invention, as described above, the protrusion heights of the internal fitting mountain portions in the plurality of internal fitting step portions, and the protrusion heights of the external fitting mountain portions in the plurality of external fitting step portions are as described above. At least one of them may be substantially the same.
“Substantially the same” in the present invention allows a manufacturing error of about 20%, and even when these manufacturing errors occur in the outer fitting mountain portion 31 and the inner fitting mountain portion 51, These areas are set to be substantially the same.

  As mentioned above, although the example of embodiment of this invention was demonstrated in detail, all the embodiment mentioned above showed only the example of actualization in implementing this invention, and these are the technical aspects of this invention. The range should not be interpreted in a limited way.

For example, the inner fitting end 5 may be attached to the first steel pipe pile 1 and the outer fitting end 3 may be attached to the second steel pipe pile 2.
Further, the outer fitting step portion 4 and the inner fitting step portion 6 may be formed in any number of steps in the axial direction Y of the outer fitting end portion 3 and the inner fitting end portion 5.
Further, in each of the outer fitting stepped portion 4 and the inner fitting stepped portion 6, each of the outer fitting mountain portion 31 and the inner fitting mountain portion 51 is arranged in a substantially staggered manner with the position in the axial direction Y being shifted. May be.
Moreover, the external fitting end part 3 or the internal fitting end part 5 is provided in the 1st steel pipe pile 1 or the 2nd steel pipe pile 2 itself by cutting the edge part of the 1st steel pipe pile 1 or the 2nd steel pipe pile 2. Also good.

  According to the present invention, it is possible to reduce the plate thickness on the distal end side of the outer fitting end portion and the inner fitting end portion to suppress an increase in material cost, and at the same time, prevent buckling deformation of the thinnest portion on the distal end side. It is possible to provide a steel pipe pile joint structure.

1: 1st steel pipe pile 2: 2nd steel pipe pile 3: Outer fitting end part 30: Outer fitting thinnest part 31: Outer fitting mountain part 32: Outer fitting groove part 33: Outer fitting trough part 34: Outer fitting front end surface 35: Outer fitting base end face 36: Outer fitting facing portion 37: Outer fitting gap 4: Outer fitting step portion 41: First outer fitting step portion 42: Second outer fitting step portion 43: Third outer fitting step portion 44: Fourth outer Fitting step 45: extra fitting extra length part 5: inner fitting end part 50: inner fitting thinnest part 51: inner fitting mountain part 52: inner fitting groove part 53: inner fitting trough part 54: inner fitting front end face 55: inner fitting Base end face 56: Inner fitting facing portions 57, 157: Inner fitting gap 6: Inner fitting step portion 61: First inner fitting step portion 62: Second inner fitting step portion 63: Third inner fitting step portion 64: Fourth inner Fitting step portion 65: Internal fitting extra length portion 7, 107, 207, 307, 407: Steel pipe pile joint structure 8: Contact surface 81: Pull side contact surface 86: Compression side contact surface P: Keyway W: Circumferential direction X: Shaft center orthogonal direction Y: Shaft center direction

Claims (6)

It is a joint structure of a steel pipe pile that connects the first steel pipe pile and the second steel pipe pile coaxially,
An outer fitting end portion provided on the first steel pipe pile, wherein a plurality of outer fitting step portions are formed along the extending direction of the first axis of the first steel pipe pile;
An inner fitting end portion provided on the second steel pipe pile, wherein a plurality of inner fitting step portions are formed along the extending direction of the second axis of the second steel pipe pile;
With
Each of the plurality of external fitting steps is
A plurality of external fitting ridges projecting in a direction toward the first axis and formed in a plurality in a circumferential direction around the first axis;
An outer fitting groove formed between the outer fitting mountain parts adjacent to each other;
An outer fitting valley portion formed on the proximal end side adjacent to each outer fitting mountain portion and close to the first steel pipe pile,
With
Each of the plurality of internally fitted steps is
A plurality of internal fitting ridges protruding in a direction away from the second axis and formed in a circumferential direction around the second axis; and
Internal fitting groove portions formed between the internal fitting mountain portions adjacent to each other;
An inner trough portion formed on the proximal end side adjacent to each inner fitting mountain portion and close to the second steel pipe pile;
With
In the plurality of external fitting step portions, the plate thickness of the external fitting valley portion is formed to be larger as the outer fitting step portion is closer to the first steel pipe pile,
In the plurality of internal fitting step portions, the plate thickness of the internal fitting valley portion is formed so as to be an internal fitting step portion closer to the second steel pipe pile,
In a state where the inner fitting end is inserted into the outer fitting end and is relatively rotated and fitted, an inner fitting tip surface on the tip side of the inner fitting end, and an opposing surface of the inner fitting tip surface Are separated by a predetermined separation distance D,
Of the contact surfaces that are in contact with each other between the plurality of outer fitting stepped portions and the plurality of inner fitting stepped portions, the total area of the tension-side contact surfaces that bear the tensile force is the outer surface that bears the compressive force. A joint structure for steel pipe piles, which is equal to or less than a total area of an area of an outer fitting front end surface on a front end side of a fitting end portion and a total area of a compression side contact surface bearing a compressive force. The joint structure of a steel pipe pile according to claim 1, wherein a total area of the tension side contact surface is equal to or less than a total area of the compression side contact surface. In the inner fitting ridge portion of the inner fitting step portion closest to the distal end side of the inner fitting end portion, h is the protruding height in the direction toward the second axis, and the length in the extending direction of the second axis. The steel pipe pile joint structure according to claim 1, wherein the predetermined separation distance D is set so as to satisfy the following formula (1) when L is defined as l.
D ≧ (h ² + l ² ) ^0.5 −l Equation (1) At least one of the protruding heights of the internal fitting ridges in the plurality of internal fitting steps and the protruding heights of the external fitting ridges in the plurality of external fitting steps are substantially the same. The steel pipe pile joint structure according to claim 1, wherein the steel pipe pile has a joint structure. The steel pipe pile joint according to any one of claims 1 to 4, wherein the facing surface of the inner fitting distal end surface is an outer fitting proximal end surface on the proximal end side of the outer fitting end portion. Construction. The steel pipe pile joint structure according to any one of claims 1 to 4, wherein the facing surface of the inner fitting front end face is an end face of the first steel pipe pile.

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