[Technical Field of the Invention]
[0001] The present invention relates to a joint structure of a steel-pipe pile for fitting
together an external fitting end portion and an internal fitting end portion capable
of being fitted to each other, at a work site, and for connecting an upper steel-pipe
pile and a lower steel-pipe pile in an axial direction, and to a steel-pipe pile using
the joint structure. More particularly, the present invention relates to a joint structure
of a steel-pipe pile and a steel-pipe pile which are used in civil engineering and
construction fields of, for example, building foundations and bridge foundations.
[Related Art]
[0003] In the related art, an object of a joint structure of a steel-pipe pile is to connect
an upper steel-pipe pile and a lower steel-pipe pile in an axial direction, the joint
structure of a steel-pipe pile is roughly classified into a screw-type, a key type,
and a gear-type, and joint structures of a steel-pipe pile disclosed in Patent Documents
1 to 3 are suggested.
[0004] In the joint structure of a steel-pipe pile disclosed in Patent Document 1, a screw-type
joint structure of a steel-pipe pile is used, a male thread portion is formed on an
end portion of one steel-pipe pile, and a female thread portion is formed on an end
portion of the other steel-pipe pile. In the joint structure of a steel-pipe pile
disclosed in Patent Document 1, for example, a lower steel-pipe pile in which the
female thread portion is formed on the end portion is buried under the ground, the
male thread portion formed on an end portion of an upper steel-pipe pile is screwed
to the female thread portion of the lower steel-pipe pile, and thus, the upper steel-pipe
pile and the lower steel-pipe pile are connected together in an axial direction.
[0005] In the joint structure of a steel-pipe pile disclosed in Patent Document 2, a key
type joint structure of a steel-pipe pile is used, a key member is assembled to an
inward groove portion of a female side end portion of a steel-pipe pile in advance,
and after a male side end portion of the steel-pipe pile is inserted into the female
side end portion of the steel-pipe pile, the key member is pushed into a center side
of the steel-pipe pile, and thus, the male side end portion of the steel-pipe pile
and the female side end portion of the steel-pipe pile engage with each other.
[0006] In the joint structure of a steel-pipe pile disclosed in Patent Document 3, a gear-type
joint structure of a steel-pipe pile is used, and although this joint structure is
based on the screw type, the problems of a screw-type joint structure of a steel-pipe
pile are solved. In the joint structure of a steel-pipe pile disclosed in Patent Document
3, a plurality of outward engagement convex portions are provided along an axial direction
in a male side end portion of a steel-pipe pile, and a plurality of inward engagement
convex portions are provided along the axial direction in a female side end portion
of the steel-pipe pile. In the joint structure of a steel-pipe pile disclosed in Patent
Document 3, the male side end portion and the female side end portion of the steel-pipe
pile are fitted together, the steel-pipe pile is relatively rotated so that the outward
engagement convex portion and the inward engagement convex portion mesh with each
other, and thus, an upper steel-pipe pile and a lower steel-pipe pile are connected
together in the axial direction.
[0007] In the joint structure of a steel-pipe pile disclosed in Patent Document 3, the outward
engagement convex portion and the inward engagement convex portion mesh with each
other. Accordingly, when a bending load or a tension load is applied to a joint portion
of the steel-pipe pile, the outward engagement convex portion and the inward engagement
convex portion come into contact with each other, and thus, the loads are transmitted
to a main body of the steel-pipe pile. It is necessary to set a contact area between
the outward engagement convex portion and the inward engagement convex portion or
an attachment area of the engagement convex portion with respect to the end portion
of the steel-pipe pile to sufficiently withstand the bearing strength or shear strength
used to transmit the loads. In addition, it is also necessary to set a thickness of
the end portion of the steel-pipe pile to sufficiently withstand the loads transmitted
from the engagement convex portions.
[Citation List]
[Patent Document]
[0008] [Patent Document 1] Japanese Unexamined Patent Application, First Publication No.
H07-82738 (Page 7 and FIG. 2)
[Patent Document 2] Japanese Unexamined Patent Application, First Publication No.
2000-257058 (Page 10 and FIG. 6)
[Patent Document 3] Japanese Unexamined Patent Application, First Publication No.
H11-43937 (Page 6 and FIG. 1)
[Summary of the Invention]
[Problems to be Solved by the Invention]
[0009] However, in the screw-type joint structure of a steel-pipe pile disclosed in Patent
Document 1, when the male thread portion of the upper steel-pipe pile is screwed to
the female thread portion of the lower steel-pipe pile, it is necessary to rotate
the upper steel-pipe pile a predetermined rotation number of times at a work site.
Accordingly, there is a problem that labor for the rotation increases and construction
costs increase. In the key type joint structure of a steel-pipe pile disclosed in
Patent Document 2, although the labor for rotating the steel-pipe pile in the screw-type
joint structure of a steel-pipe pile can be omitted, the key member is separately
required, and complicated machining is required in which the inward groove portion
is formed on the female side end portion of the steel-pipe pile and the key member
is assembled in advance. Accordingly, there is a problem that machining costs increase
and the cost of materials in a joint portion of the steel-pipe pile also increase
to withstand the complicated machining.
[0010] Moreover, in the gear-type joint structure of a steel-pipe pile disclosed in Patent
Document 3, when the male side end portion of the steel-pipe pile is inserted into
the female side end portion of the steel-pipe pile, a notch portion is provided between
engagement convex portions adjacent in the circumferential direction of the steel-pipe
pile so that the outward engagement convex portion and the inward engagement convex
portion do not interfere with each other. Moreover, the engagement convex portions
and the notch portion are provided in a row in the axial direction. Accordingly, in
the joint structure of a steel-pipe pile disclosed in Patent Document 3, there are
the following problems.
[0011] In the joint structure of a steel-pipe pile disclosed in Patent Document 3, the engagement
convex portions are intermittently provided in the circumferential direction of the
steel-pipe pile, and thus, are provided in a row in the axial direction. Accordingly,
a cross-sectional defect occurs when viewed in the axial direction, and the bending
load and the tension load which can be transmitted to the engagement convex portion
are decreased by the cross-sectional defect. Therefore, in the joint structure of
a steel-pipe pile disclosed in Patent Document 3, in order to withstand a predetermined
bending load and tension load, it is necessary to use the engagement convex portion
enlarged by the cross-sectional defect when viewed in the axial direction, and it
is necessary to increase the number of steps of the engagement convex portion in the
axial direction. Accordingly, there is a problem that machining costs and the cost
of materials in the joint structure of the steel-pipe pile increase.
[0012] Moreover, in the joint structure of a steel-pipe pile disclosed in Patent Document
3, since the engagement convex portions are provided in a row in the axial direction,
the bending load and the tension load transmitted from the engagement convex portion
to the main body of the steel-pipe pile cannot be uniform in the circumferential direction
of the steel-pipe pile. Accordingly, the bending load and the tension load are concentrated
at a predetermined engagement convex portion. Therefore, in the joint structure of
a steel-pipe pile disclosed in Patent Document 3, in a design with respect to a plate
thickness of the steel-pipe pile, since the plate thickness is set based on the portion
at which the bending load and the tension load are concentrated, the plate thickness
increases, and thus, there is a problem that the cost of materials of the joint structure
increases.
[0013] In addition, in the joint structure of a steel-pipe pile disclosed in Patent Document
3, when the bending load is applied to the steel-pipe pile, the portion in which the
engagement convex portions are provided in a row in the axial direction may not be
disposed at the portion corresponding to the outermost edge end portion of the steel-pipe
pile at which tensile stress becomes maximum. At this time, the bending load is applied
to the portion in which the cross-sectional defect is formed, and thus, there is a
concern that the steel-pipe pile cannot withstand the bending load and the joint portion
of the steel-pipe pile may be damaged. Accordingly, in the joint structure of a steel-pipe
pile disclosed in Patent Document 3, there is a problem that a structural defect occurs.
[0014] Therefore, the present invention is made in consideration of the above-described
problems, and an object thereof is to provide a joint structure of a steel-pipe pile
and a steel-pipe pile in which an increase in labor for rotation of the steel-pipe
pile at a work site is prevented, an excessive increase in a plate thickness of the
steel-pipe pile is avoided, and there is no concern of damage even when the bending
load is applied.
[Means for Solving the Problem]
[0015] In order to solve the above-described problems, the present invention adopts the
following measures.
(1) According to a first aspect of the present invention, there is provided a joint
structure of a steel-pipe pile which connects a first steel-pipe pile and a second
steel-pipe pile in series, the joint structure including: an external fitting end
portion which is an opening end of the first steel-pipe pile; and a column shaped
internal fitting end portion which configures a portion inserted into the external
fitting end portion on one end of the second steel-pipe pile, in which the external
fitting end portion includes a plurality of external fitting convex portions which
protrude from an inner circumferential surface of the external fitting end portion
toward an inner side in a radial direction of the first steel-pipe pile, and are provided
along a circumferential direction of the first steel-pipe pile; an external fitting
groove portion which is formed between the external fitting convex portions adjacent
to each other in the circumferential direction of the first steel-pipe pile; and an
external fitting engagement groove which is formed along the circumferential direction
at a position of an inner side in an axial direction of the first steel-pipe pile
from the external fitting convex portion and the external fitting groove portion on
the inner circumferential surface, the internal fitting end portion includes a plurality
of internal fitting convex portions which protrude from an outer circumferential surface
of the internal fitting end portion toward an outer side in a radial direction of
the second steel-pipe pile, and are provided along a circumferential direction of
the second steel-pipe pile, each of the internal fitting convex portions engages with
each of the external fitting convex portions in the external fitting engagement groove
after the internal fitting end portion is inserted into the external fitting end portion
and the first steel-pipe pile and the second steel-pipe pile are relatively rotated
around an axis of the first steel-pipe pile, the external fitting convex portions
and the external fitting groove portions are formed into a plurality of rows along
the axial direction of the first steel-pipe pile, and in at least one set of two rows
adjacent to each other among the plurality of rows adjacent to one another, the external
fitting convex portions of one row and the external fitting groove portions of the
other row are provided to be adjacent in the radial direction of the first steel-pipe
pile when viewed in the axial direction of the first steel-pipe pile.
(2) In the aspect according to the above (1), the external fitting end portion may
include a plurality of step portions formed along the axial direction of the first
steel-pipe pile, the external fitting convex portions and the external fitting groove
portions by at least one row may be provided in each of the plurality of step portions,
and in two step portions adjacent to each other, the external fitting convex portions
of one step portion and the external fitting groove portions of the other step portion
may be provided to be adjacent in the radial direction of the first steel-pipe pile
when viewed in the axial direction of the first steel-pipe pile.
(3) In the aspect according to the above (2), in the two step portions adjacent to
each other, the external fitting convex portions of the one step portion may be provided
at all positions adjacent to the external fitting groove portions of the other step
portion in the radial direction of the first steel-pipe pile when viewed in the axial
direction of the first steel-pipe pile, and the external fitting convex portions may
be provided without gaps along the circumferential direction of the first steel-pipe
pile when viewed in the axial direction of the first steel-pipe pile.
(4) In the aspect according to the above (2) or (3), the first steel-pipe pile may
be thickened in stages along the axial direction of the first steel-pipe pile, and
the plurality of step portions adjacent to one another in the axial direction of the
first steel-pipe pile may be formed so that the external fitting convex portions of
the step portion positioned at an outer side in the axial direction of the first steel-pipe
pile and the external fitting groove portions of the step portion positioned at the
inner side in the axial direction of the first steel-pipe pile all have approximately
the same thickness.
(5) In the aspect according to any one of the above (1) to (4), the internal fitting
end portion may include an internal fitting edge which forms a gap between a tip portion
of the external fitting end portion and the internal fitting end portion at the inner
side in the axial direction of the second steel-pipe pile in a state where the internal
fitting end portion is inserted into the external fitting end portion, the external
fitting convex portion may include a first tapered portion which is inclined along
the circumferential direction of the first steel-pipe pile on an end surface in the
inner side in the axial direction of the first steel-pipe pile so that a height in
the axial direction of the first steel-pipe pile is approximately the same as a height
of the gap, the external fitting engagement groove may include a second tapered portion
which is inclined in the circumferential direction of the first steel-pipe pile to
be approximately parallel with the first tapered portion at a portion facing the first
tapered portion in the axial direction of the first steel-pipe pile, the internal
fitting convex portion may include a third tapered portion which is inclined along
the circumferential direction of the second steel-pipe pile to abut the first tapered
portion on an end surface in the inner side in the axial direction of the second steel-pipe
pile, and a fourth tapered portion which is inclined along the circumferential direction
of the second steel-pipe pile to abut the second tapered portion on an end surface
in the outer side in the axial direction of the second steel-pipe pile, and the first
steel-pipe pile and the second steel-pipe pile may relatively rotate around the axis
of the first steel-pipe pile, the first tapered portion and the third tapered portion
may abut each other, the second tapered portion and the fourth tapered portion may
abut each other, the plurality of external fitting convex portions and the plurality
of internal fitting convex portions may engage with each other, the internal fitting
edge and the tip portion may abut each other to fill the gap, and the external fitting
end portion and the internal fitting end portion may be fitted together.
(6) According to a second aspect of the present invention, there is provided a steel-pipe
pile including the joint structure of a steel-pipe pile according to any one of the
above (1) to (5).
[Effects of the Invention]
[0016] According to the aspects of the above (1) to (6), in at least one set of two rows
among the plurality of rows adjacent to one another in the axial direction of the
steel-pipe pile, since the external fitting convex portions of the one row and the
external fitting groove portions of the other row are provided to be adjacent to each
other in the radial direction of the steel-pipe pile when viewed in the axial direction
of the steel-pipe pile, a cross-sectional defect does not occur when viewed in the
axial direction, and the lower steel-pipe pile and the upper steel-pipe pile can be
connected together. Accordingly, in order to withstand a predetermined bending load
and tension load, it is not necessary to enlarge the external fitting convex portions
and the internal fitting convex portions by the cross-sectional defects, and it is
not necessary to increase the number of steps in the external fitting step portion
and the internal fitting step portion beyond the number necessary to do something,
and thus, it is possible to avoid a case where a machining coat or the cost of materials
of the joint structure of a steel-pipe pile is increased.
[0017] Moreover, according to the aspects of the above (1) to (6), in at least one set of
two rows among the plurality of rows adjacent to one another in the axial direction
of the steel-pipe pile, since the external fitting convex portions of the one row
and the external fitting groove portions of the other row are provided to be adjacent
to each other in the radial direction of the steel-pipe pile when viewed in the axial
direction of the steel-pipe pile, the bending load and the tension load applied to
the external fitting convex portion and the internal fitting convex portion can be
uniform in the circumferential direction. Accordingly, the loads transmitted from
the external fitting convex portions and the internal fitting convex portions to a
main body of the steel-pipe pile can be uniform in the circumferential direction,
and an increase in a plate thickness of the steel-pipe pile can be avoided. Therefore,
it is possible to avoid a case where the cost of materials of the joint structure
is increased.
[0018] According to the aspects of the above (1) to (6), in at least one set of two rows
among the plurality of rows adjacent to one another in the axial direction of the
steel-pipe pile, since the external fitting convex portions of the one row and the
external fitting groove portions of the other row are provided to be adjacent to each
other in the radial direction of the steel-pipe pile when viewed in the axial direction
of the steel-pipe pile, even when the bending load is applied to a portion at which
the lower steel-pipe pile and the upper steel-pipe pile are connected together, any
external fitting convex portion of the plurality of rows and any internal fitting
convex portion of the plurality of rows can be accurately disposed on a portion corresponding
to the outermost edge end portion of the steel-pipe pile at which tensile stress becomes
the maximum. Accordingly, the bending load can be accurately applied to any external
fitting convex portion and any internal fitting convex portion, and it is possible
to avoid a case where the external fitting end portion and the internal fitting end
portion are damaged.
[0019] Particularly, according to the aspect of the above (2), in two step portions adjacent
to each other in the axial direction of the steel-pipe pile, since the external fitting
convex portions of the one step portion and the external fitting groove portions of
the other step portion are provided to be adjacent to each other in the radial direction
of the steel-pipe pile when viewed in the axial direction of the steel-pipe pile,
the upper steel-pipe pile can be inserted into the lower steel-pipe pile while the
external fitting convex portions and the internal fitting convex portions do not interfere
with each other.
[0020] Particularly, according to the aspect of the above (3), since the external fitting
convex portions provided in each of the plurality of step portions are formed to fill
gaps along the circumferential direction when viewed in the axial direction of the
steel-pipe pile, contact areas between the external fitting convex portions and the
internal fitting convex portions are maximized, and load bearing capacity with respect
to the tensile load and the bending load can be increased.
[0021] Particularly, according to the aspect of the above (4), the plate thickness of the
steel-pipe pile is thickened in stages along the axial direction from the outer side
(upper side) in the axial direction of the lower steel-pipe pile toward the inner
side (lower side) in the axial direction, and from the outer side (lower side) in
the axial direction of the upper steel-pipe pile toward the inner side (upper side)
in the axial direction, and thus, a plurality of step portions are formed. Accordingly,
a structure in which the plate thickness of the steel-pipe pile is increased in stages
according to the number of steps of the external fitting convex portions and the internal
fitting convex portions in the axial direction can be easily realized.
[0022] Particularly, according to the aspect of the above (5), in the state where the external
fitting convex portions and the internal fitting convex portions engage with each
other in the axial direction, the tip portion of the external fitting end portion
and the internal fitting edge of the internal fitting end portion abut each other,
and thus, complete fitting between the external fitting end portion and the internal
fitting end portion can be visually confirmed from the outside. In addition, the third
tapered portion abuts the first tapered portion, the fourth tapered portion abuts
the second tapered portion, and thus, the internal fitting convex portion can smoothly
move in the circumferential direction on the external fitting engagement groove, and
the external fitting end portion and the internal fitting end portion can be easily
fitted together. Moreover, since the internal fitting convex portion is locked by
the locking portion formed on the external fitting engagement groove, an excessive
rotation of the steel-pipe pile can be prevented.
[Brief Description of the Drawings]
[0023]
FIG. 1 is a perspective view showing a state where steel-pipe piles are connected
together using a joint structure of a steel-pipe pile according to a first embodiment
of the present invention.
FIG. 2 is a perspective view showing the joint structure of a steel-pipe pile according
to the first embodiment of the present invention.
FIG. 3 is a partially cutaway side view showing an external fitting end portion according
to the first embodiment of the present invention.
FIG. 4A is a plan view showing the external fitting end portion according to the first
embodiment of the present invention.
FIG. 4B is a plan view showing a modification of the external fitting end portion.
FIG. 5 is an enlarged front view showing an external fitting convex portion, an external
fitting groove portion, and an external fitting engagement groove.
FIG. 6 is a view taken along line A-A of FIG. 5 and showing the external fitting convex
portion, the external fitting groove portion, and the external fitting engagement
groove.
FIG. 7 is a side view showing an internal fitting end portion according to the first
embodiment of the present invention.
FIG. 8A is a plan view showing the internal fitting end portion according to the first
embodiment of the present invention.
FIG. 8B is a plan view showing a modification of the internal fitting end portion.
FIG. 9 is an enlarged front view showing an internal fitting convex portion, an internal
fitting groove portion, and an internal fitting engagement groove.
FIG. 10 is a view taken along line B-B of FIG. 9 and showing the internal fitting
convex portion, the internal fitting groove portion, and the internal fitting engagement
groove.
FIG. 11 is a perspective view showing a state where the internal fitting end portion
is inserted into the external fitting end portion in the first embodiment of the present
invention.
FIG. 12 is a partial cross-sectional perspective view showing a state where the internal
fitting end portion is inserted into the external fitting end portion in the first
embodiment of the present invention.
FIG. 13 is an enlarged perspective view showing a state where the internal fitting
convex portion passes through the external fitting groove portion in the first embodiment
of the present invention.
FIG. 14A is an enlarged front view showing the state where the internal fitting convex
portion passes through the external fitting groove portion in the first embodiment
of the present invention.
FIG. 14B is an enlarged view which shows a portion indicated by a two-dot chain line
of FIG. 14A and shows a modification of the external fitting convex portion.
FIG. 15 is a perspective view showing a state where an upper steel-pipe pile relatively
rotates in the first embodiment of the present invention.
FIG. 16 is an enlarged perspective view showing a state where the external fitting
convex portion and the internal fitting convex portion engage with each other in the
first embodiment of the present invention.
FIG. 17 is an enlarged front view showing a state where the external fitting convex
portion and the internal fitting convex portion engage with each other in the first
embodiment of the present invention.
FIG. 18 is a perspective view showing a modified shape of the joint structure of the
steel-pipe pile according to the first embodiment of the present invention.
FIG. 19 is a perspective view showing a modified shape of the joint structure of the
steel-pipe pile according to the first embodiment of the present invention, which
is different from FIG. 18.
FIG. 20 is a perspective view showing a joint structure of a steel-pipe pile according
to a second embodiment of the present invention.
FIG. 21A is a plan view showing an external fitting end portion in the second embodiment
of the present invention.
FIG. 21B is a plan view showing a modification of the external fitting end portion.
FIG. 22A is a plan view showing an internal fitting end portion in the second embodiment
of the present invention.
FIG. 22B is a plan view showing a modification of the internal fitting end portion.
FIG. 23 is an enlarged perspective view showing a state where an internal fitting
convex portion passes through an external fitting groove portion in the second embodiment
of the present invention.
FIG. 24 is an enlarged front view showing a state where the internal fitting convex
portion passes through the external fitting groove portion in the second embodiment
of the present invention.
FIG. 25 is a perspective view showing a state where the upper steel-pipe pile relatively
rotates in the second embodiment of the present invention.
FIG. 26 is an enlarged perspective view showing a state where the external fitting
convex portion and the internal fitting convex portion engage with each other in the
second embodiment of the present invention.
FIG. 27 is an enlarged front view showing a state where the external fitting convex
portion and the internal fitting convex portion engage with each other in the second
embodiment of the present invention.
[Embodiments of the Invention]
[0024] Hereinafter, embodiments of the present invention will be described in detail with
reference to the drawings.
(First Embodiment)
[0025] First, a joint structure of a steel-pipe pile according to a first embodiment of
the present invention will be described with reference to FIGS. 1 and 2. As shown
in FIG. 1, the joint structure 1 of a steel-pipe pile according to the first embodiment
is used to connect (join) a lower steel-pipe pile 2 (first steel-pipe pile) and an
upper steel-pipe pile 3 (second steel-pipe pile) along an axial direction X.
[0026] As shown in FIG. 2, the joint structure 1 includes an external fitting end portion
20 provided on an upper end (opening end) of the lower steel-pipe pile 2, and a column
shaped internal fitting end portion 30 provided on a lower end (one end) of the upper
steel-pipe pile 3. In the joint structure 1, the internal fitting end portion 30 of
the upper steel-pipe pile 3 is fitted to the external fitting end portion 20 of the
lower steel-pipe pile 2 which is buried under the ground.
[0027] In the joint structure 1 of the first embodiment, two external fitting step portions
29 (29a and 29b) arranged in the axial direction X of the lower steel-pipe pile 2
are provided on the external fitting end portion 20, and two internal fitting step
portions 39 (39a and 39b) arranged in the axial direction X of the upper steel-pipe
pile 3 are provided on the internal fitting end portion 30.
[0028] As shown in FIG. 3, a tip portion 28 of the external fitting end portion 20 is formed
on the external fitting end portion 20. Each external fitting step portion 29 (29a
and 29b) includes a plurality of external fitting convex portions 21 which are formed
to protrude toward a center side (an inner side in a radial direction) in an axis
orthogonal direction Y (a direction (radial direction) orthogonal to the axial direction
X: refer to FIG. 1) of the lower steel-pipe pile 2 on an inner wall surface (inner
circumferential surface) of the external fitting end portion 20, a plurality of external
fitting groove portions 22 which are formed among the plurality of external fitting
convex portions 21, and an external fitting engagement groove 23 which is formed on
the inner side (lower side) in the axial direction X of the lower steel-pipe pile
2 from the plurality of external fitting convex portions 21 and the plurality of external
fitting groove portions 22.
[0029] A plate thickness of the lower steel-pipe pile 2 is thickened in stages in the axial
direction X and the external fitting step portion 29 is formed so that the external
fitting convex portions 21 of the first external fitting step portion 29a in the outer
side (upper side) in the axial direction X of the lower steel-pipe pile 2, and the
external fitting groove portions 22 of the second external fitting step portion 29b
in the inner side (lower side) in the axial direction X of the lower steel-pipe pile
2 have approximately the same thickness in the axis orthogonal direction Y of the
lower steel-pipe pile 2. The external fitting convex portion 21 of the first external
fitting step portion 29a has a thickness having a predetermined width t1 in the axis
orthogonal direction Y on the outer side (upper side) in the axial direction X of
the lower steel-pipe pile 2.
[0030] In each external fitting step portion 29 (29a and 29b), the external fitting convex
portion 21 is formed to protrude in an approximately rectangular shape in the axis
orthogonal direction Y of the lower steel-pipe pile 2. In each external fitting step
portion 29 (29a and 29b), the external fitting groove portions 22 are formed among
the plurality of external fitting convex portions 21, and each external fitting groove
portion has a predetermined width in a circumferential direction Z (refer to FIG.
1) of the lower steel-pipe pile 2. In each external fitting step portion 29 (29a and
29b), the external fitting engagement groove 23 is formed on the inner side (lower
side) in the axial direction X of the lower steel-pipe pile 2 from the external fitting
convex portions 21 and the external fitting groove portions 22, and has a predetermined
height in the axial direction X of the lower steel-pipe pile 2 and approximately the
same thickness as the external fitting groove portion 22 in the axis orthogonal direction
Y.
[0031] The external fitting convex portions 21 are formed on the first external fitting
step portion 29a on the outer side (upper side) in the axial direction X of the lower
steel-pipe pile 2, and the second external fitting step portion 29b adjacent to the
first external fitting step portion 29a on the inner side (lower side) in the axial
direction X of the lower steel-pipe pile 2 from the first external fitting step portion
29a. At this time, the external fitting convex portions 21 of the first external fitting
step portion 29a and the external fitting convex portions 21 of the second external
fitting step portion 29b are formed at positions which deviate in the axial direction
X. In other words, the external fitting convex portions 21 of the first external fitting
step portion 29a and the external fitting convex portions 21 of the second external
fitting step portion 29b are formed at positions different from each other in the
axial direction X.
[0032] As shown in FIG. 4A, in the external fitting end portion 20, the external fitting
convex portions 21 are formed on the first external fitting step portion 29a, and
the external fitting convex portions 21 of the second external fitting step portion
29b are formed at all positions adjacent to the external fitting groove portions 22
formed on the first external fitting step portion 29a in the axis orthogonal direction
Y when viewed in the axial direction. Accordingly, the external fitting convex portions
21 of the first external fitting step portion 29a and the external fitting convex
portions 21 of the second external fitting step portion 29b are alternately formed
without gaps in the circumferential direction Z when viewed in the axial direction.
[0033] In addition, the external fitting convex portions 21 are not limited to the above,
and for example, as shown in FIG. 4B, the external fitting convex portions 21 of the
second external fitting step portion 29b may be formed at partial positions adjacent
to the external fitting groove portions 22 formed on the first external fitting step
portion 29a in the axis orthogonal direction Y when viewed in the axial direction.
In other words, the external fitting convex portions 21 of the first external fitting
step portion 29a and the external fitting convex portions 21 of the second external
fitting step portion 29b may be alternately formed with gaps in the circumferential
direction Z when viewed in the axial direction.
[0034] As shown in FIGS. 5 and 6, the external fitting convex portion 21 includes a first
tapered portion 21a which is linearly inclined in the circumferential direction Z
of the lower steel-pipe pile 2 on the lower end surface in the inner side (lower side)
in the axial direction X of the lower steel-pipe pile 2. Moreover, the external fitting
engagement groove 23 includes a second tapered portion 23 a which is linearly inclined
in the circumferential direction Z of the lower steel-pipe pile 2 to be approximately
parallel with the first tapered portion 21 a at the portion facing the first tapered
portion 21 a in the axial direction X of the lower steel-pipe pile 2. The external
fitting engagement groove 23 includes a locking portion 23b extending in the axial
direction X at the termination of the second tapered portion 23a.
[0035] The first tapered portion 21 a has a predetermined height h in the axial direction
X of the lower steel-pipe pile 2. The second tapered portion 23a extends in a portion
facing the first tapered portion 21a in the axial direction X of the lower steel-pipe
pile 2 and extends to the entire portion positioned below the external fitting groove
portion 22. In addition, the second tapered portion 23a is not limited to the above,
and for example, as shown in FIG. 5, the second tapered portion may extend to an intermediate
portion 23c positioned below the external fitting groove portion 22. Moreover, as
described above, the first tapered portion 21a and the second tapered portion 23a
are linearly formed on the external fitting convex portion 21 and the external fitting
engagement groove 23. However, the first tapered portion 21a and the second tapered
portion 23a may be formed to be inclined in an arc shape on the external fitting convex
portion 21 and the external fitting engagement groove 23. In addition, the first tapered
portion 21a and the second tapered portion 23a may be separately formed with respect
to the external fitting convex portion 21 and the external fitting engagement groove
23.
[0036] In the internal fitting end portion 30, as shown in FIG. 7, an internal fitting edge
38, which is formed to protrude toward the outer side in the axis orthogonal direction
Y of the upper steel-pipe pile 3, is formed on the inner side (upper side) in the
axial direction X of the upper steel-pipe pile 3 from the two internal fitting step
portions 39 (39a and 39b).
[0037] In each internal fitting step portion 39 (39a and 39b), the internal fitting end
portion 30 includes a plurality of internal fitting convex portions 31 which are formed
to protrude toward the outer side in an axis orthogonal direction Y of the upper steel-pipe
pile 3 on an outer wall surface (outer circumferential surface) of the internal fitting
end portion 30, a plurality of internal fitting groove portions 32 which are formed
among the plurality of internal fitting convex portions 31, and an internal fitting
engagement groove 33 which is formed on the inner side (upper side) in the axial direction
X of the upper steel-pipe pile 3 from the plurality of internal fitting convex portions
31 and the plurality of internal fitting groove portions 32.
[0038] A plate thickness of the upper steel-pipe pile 3 is thickened in stages in the axial
direction X and the internal fitting step portion 39 is formed so that the internal
fitting groove portions 32 of the first internal fitting step portion 39a in the inner
side (upper side) in the axial direction X of the upper steel-pipe pile 3, and the
internal fitting convex portions 31 of the second internal fitting step portion 39b
in the outer side (lower side) in the axial direction X of the upper steel-pipe pile
3 have approximately the same thickness in the axis orthogonal direction Y of the
upper steel-pipe pile 3. The internal fitting engagement groove 33 of the first internal
fitting step portion 39a has a space having a predetermined width t2 in the axis orthogonal
direction Y of the upper steel-pipe pile 3.
[0039] In each internal fitting step portion 39 (39a and 39b), the internal fitting convex
portion 31 is formed to protrude in an approximately rectangular shape in the axis
orthogonal direction Y of the upper steel-pipe pile 3. In each internal fitting step
portion 39 (39a and 39b), the internal fitting groove portions 32 are formed among
the plurality of internal fitting convex portions 31, and each internal fitting groove
portion has a predetermined width in a circumferential direction Z of the upper steel-pipe
pile 3. The internal fitting engagement groove 33 is formed on the inner side (upper
side) in the axial direction X of the upper steel-pipe pile 3 from the internal fitting
convex portions 31 and the internal fitting groove portions 32, and is formed so that
the width t2 (refer to FIG. 7) of the space between the internal fitting engagement
grooves 33 in the first internal fitting step portion 39a is equal to or more than
the width t1 (refer to FIG. 3) of the plate thickness of the external fitting convex
portion 21 in the first external fitting step portion 29a. Moreover, in each internal
fitting step portion 39, the internal fitting engagement groove 33 has a predetermined
height in the axial direction X of the upper steel-pipe pile 3 and approximately the
same thickness as the internal fitting groove portion 32 in the axis orthogonal direction
Y.
[0040] The internal fitting convex portions 31 are formed on the first internal fitting
step portion 39a on the inner side (upper side) in the axial direction X of the upper
steel-pipe pile 3, and the second internal fitting step portion 39b adjacent to the
first internal fitting step portion 39a on the outer side (lower side) in the axial
direction X of the upper steel-pipe pile 3 from the first internal fitting step portion
39a. At this time, the internal fitting convex portions 31 of the first internal fitting
step portion 39a and the internal fitting convex portions 31 of the second internal
fitting step portion 39b are formed at positions which deviate in the axial direction
X. In other words, the internal fitting convex portions 31 of the first internal fitting
step portion 39a and the internal fitting convex portions 31 of the second internal
fitting step portion 39b are formed at positions different from each other in the
axial direction X.
[0041] As shown in FIG. 8A, the internal fitting convex portions 31 of the second internal
fitting step portion 39b are formed at all positions adjacent to the internal fitting
groove portions 32 formed on the first internal fitting step portion 39a in the axis
orthogonal direction Y when viewed in the axial direction. Accordingly, the internal
fitting convex portions 31 of the first internal fitting step portion 39a and the
internal fitting convex portions 31 of the second internal fitting step portion 39b
are alternately formed without gaps in the circumferential direction Z when viewed
in the axial direction.
[0042] In addition, the internal fitting convex portions 31 are not limited to the above,
and for example, as shown in FIG. 8B, the internal fitting convex portions 31 of the
second internal fitting step portion 39b may be formed at partial positions adjacent
to the internal fitting groove portions 32 formed on the first internal fitting step
portion 39a in the axis orthogonal direction Y when viewed in the axial direction.
In other words, the internal fitting convex portions 31 of the first internal fitting
step portion 39a and the internal fitting convex portions 31 of the second internal
fitting step portion 39b may be alternately formed with gaps in the circumferential
direction Z when viewed in the axial direction.
[0043] As shown in FIGS. 9 and 10, the internal fitting convex portion 31 includes a third
tapered portion 31a which is linearly inclined in the circumferential direction Z
of the upper steel-pipe pile 3 to abut the first tapered portion 21a shown in FIG.
5 and to be approximately parallel with the first tapered portion 21a on the upper
end surface in the inner side (upper side) in the axial direction X of the upper steel-pipe
pile 3. Moreover, the internal fitting convex portion 31 includes a fourth tapered
portion 31b which is linearly inclined in the circumferential direction Z of the upper
steel-pipe pile 3 to abut the second tapered portion 23a shown in FIG. 5 and to be
approximately parallel with the second tapered portion 23a and the third tapered portion
31a on the lower end surface in the outer side (lower side) in the axial direction
X of the upper steel-pipe pile 3.
[0044] The third tapered portion 31a and the fourth tapered portion 31b have a predetermined
height h in the axial direction X of the upper steel-pipe pile 3. Moreover, as described
above, the third tapered portion 31a and the fourth tapered portion 31b are linearly
formed on the internal fitting convex portion 31. However, the third tapered portion
31a and the fourth tapered portion 31b may be formed to be inclined in an arc shape
on the internal fitting convex portion 31. In addition, the third tapered portion
31a and the fourth tapered portion 31b may be separately formed with respect to the
internal fitting convex portion 31.
[0045] Next, a method for connecting the lower steel-pipe pile 2 and the upper steel-pipe
pile 3 together using the joint structure 1 of a steel-pipe pile according to the
first embodiment will be described in detail with reference to the drawings.
[0046] First, as shown in FIGS. 11 and 12, the internal fitting end portion 30 of the upper
steel-pipe pile 3 is inserted into the external fitting end portion 20 of the lower
steel-pipe pile 2 along the axial direction X. Here, FIG. 11 is a view showing a state
where the internal fitting end portion 30 is inserted into the external fitting end
portion 20, and FIG. 12 is a view showing a state where the internal fitting end portion
30 is further inserted into the external fitting end portion 20 from the state of
FIG. 11. As shown in FIGS. 13 and 14A, the internal fitting end portion 30 is inserted
into the external fitting end portion 20, and thus, the internal fitting convex portions
31 of the first internal fitting step portion 39a pass through the external fitting
groove portions 22 of the first external fitting step portion 29a and abut the lower
end surface of the external fitting engagement groove 23 of the first external fitting
step portion 29a. Moreover, the internal fitting convex portions 31 of the second
internal fitting step portion 39b pass through the external fitting groove portions
22 of the second external fitting step portion 29b and abut the lower end surface
of the external fitting engagement groove 23 of the second external fitting step portion
29b. Moreover, FIG. 14B shows a state where the internal fitting convex portions 31
of the first internal fitting step portion 39a abut the lower end surface of the external
fitting engagement groove 23 of the first external fitting step portion 29a when the
second tapered portion 23a extends to the intermediate portion 23c (refer to FIG.
5).
[0047] Here, as described above, in the joint structure 1, the external fitting convex portions
21 of the first external fitting step portion 29a and the external fitting groove
portions 22 of the second external fitting step portion 29b are formed to all have
approximately the same thicknesses in the axis orthogonal direction Y of the lower
steel-pipe pile 2, and the internal fitting groove portions 32 of the first internal
fitting step portion 39a and the internal fitting convex portions 31 of the second
internal fitting step portion 39b are formed to all have approximately the same thicknesses
in the axis orthogonal direction Y of the upper steel-pipe pile 3. Accordingly, the
internal fitting end portion 30 of the upper steel-pipe pile 3 can be inserted into
the external fitting end portion 20 of the lower steel-pipe pile 2 without interference
between the internal fitting convex portions 31 of the second internal fitting step
portion 39b and the external fitting convex portions 21 of the first external fitting
step portion 29a.
[0048] At this time, as shown in FIG. 14A, in the state where the internal fitting end portion
30 of the upper steel-pipe pile 3 is inserted into the external fitting end portion
20 of the lower steel-pipe pile 2, a gap d having a predetermined height in the axial
direction X is formed between the tip portion 28 of the external fitting end portion
20 and the internal fitting edge 38 of the internal fitting end portion 30.
[0049] Next, as shown in FIG. 15, the lower steel-pipe pile 2 and the upper steel-pipe pile
3 are relatively rotated in the circumferential direction Z around the axis. Accordingly,
as shown in FIGS. 16 and 17, the internal fitting convex portions 31 move to portions
under the external fitting convex portions 21 along the circumferential direction
Z and engage with the external fitting convex portions 21 in the axial direction X.
In this way, the external fitting end portion 20 of the lower steel-pipe pile 2 and
the internal fitting end portion 30 of the upper steel-pipe pile 3 are fitted together.
[0050] Here, the first tapered portion 21a and the second tapered portion 23 a shown in
FIG. 5 and the third tapered portion 31a and the fourth tapered portion 31b shown
in FIG. 9 have the predetermined height h in the axial direction X of the lower steel-pipe
pile 2 and the upper steel-pipe pile 3. The height h is set to be approximately the
same as the height of the gap d which is formed between the tip portion 28 of the
external fitting end portion 20 and the internal fitting edge 38 of the internal fitting
end portion 30.
[0051] At this time, as shown in FIG. 17, the third tapered portion 31a (refer to FIG. 9)
abuts the first tapered portion 21a (refer to FIG. 5), and the fourth tapered portion
31b (refer to FIG. 9) abuts the second tapered portion 23a (refer to FIG. 5), and
thus, the internal fitting convex portion 31 of the upper steel-pipe pile 3 moves
in the circumferential direction Z on the external fitting engagement groove 23 of
the lower steel-pipe pile 2. Accordingly, the lower steel-pipe pile 2 and the upper
steel-pipe pile 3 approach each other in the axial direction X, and thus, the tip
portion 28 of the external fitting end portion 20 and the internal fitting edge 38
of the internal fitting end portion 30 abut each other to fill the gap d.
[0052] Accordingly, in the joint structure 1, in the state where the external fitting convex
portions 21 and the internal fitting convex portions 31 engage with each other in
the axial direction X, the tip portion 28 of the external fitting end portion 20 and
the internal fitting edge 38 of the internal fitting end portion 30 abut each other
to fill the gap d. Accordingly, whether or not the external fitting end portion 20
of the lower steel-pipe pile 2 and the internal fitting end portion 30 of the upper
steel-pipe pile 3 are completely fitted together can be determined by visually confirming
the gap d from the outside.
[0053] Moreover, after the external fitting end portion 20 of the lower steel-pipe pile
2 and the internal fitting end portion 30 of the upper steel-pipe pile 3 are fitted
together, a feeler gauge abuts the gap d, and the fitting between the external fitting
end portion 20 and the internal fitting end portion 30 may be confirmed according
to whether or not the feeler gauge passes through the gap d. In this case, compared
to the above-described visual confirmation method, whether or not the external fitting
end portion 20 and the internal fitting end portion 30 are fitted together can be
more accurately determined.
[0054] In addition, as shown in FIG. 17, the third tapered portion 31a (refer to FIG. 9)
abuts the first tapered portion 21a (refer to FIG. 5), and the fourth tapered portion
31b (refer to FIG. 9) abuts the second tapered portion 23 a (refer to FIG. 5), and
thus, the internal fitting convex portion 31 of the upper steel-pipe pile 3 can smoothly
move in the circumferential direction Z on the external fitting engagement groove
23 of the lower steel-pipe pile 2, and the external fitting end portion 20 of the
lower steel-pipe pile 2 and the internal fitting end portion 30 of the upper steel-pipe
pile 3 can be easily fitted together. In addition, in the joint structure 1, the internal
fitting convex portion 31 of the upper steel-pipe pile 3 is locked to the locking
portion 23b (refer to FIG. 5) of the external fitting engagement groove 23 of the
lower steel-pipe pile 2. Accordingly, the external fitting end portion 20 of the lower
steel-pipe pile 2 and the internal fitting end portion 30 of the upper steel-pipe
pile 3 can be fitted together while the upper steel-pipe pile 3 is not rotated more
than necessary.
[0055] In the joint structure 1, in the state where the external fitting end portion 20
of the lower steel-pipe pile 2 and the internal fitting end portion 30 of the upper
steel-pipe pile 3 are fitted together, the internal fitting convex portions 31 formed
on the first internal fitting step portion 39a engage with the external fitting convex
portions 21 formed on the first external fitting step portion 29a, the internal fitting
convex portions 31 formed on the second internal fitting step portion 39b engage with
the external fitting convex portions 21 formed on the second external fitting step
portion 29b, and thus, a bending load and a tension load are transmitted to the main
body of the steel-pipe pile. Moreover, in the joint structure 1, the external fitting
convex portions 21 formed on the first external fitting step portion 29a and the external
fitting convex portions 21 formed on the second external fitting step portion 29b
are provided at positions which deviate in the axial direction X. Accordingly, in
the joint structure 1 of a steel-pipe pile, the lower steel-pipe pile 2 and the upper
steel-pipe pile 3 can be connected together without a cross-sectional defect when
viewed in the axial direction.
[0056] Accordingly, in the joint structure 1, in the state where the external fitting end
portion 20 of the lower steel-pipe pile 2 and the internal fitting end portion 30
of the upper steel-pipe pile 3 are fitted together, it is possible to avoid a case
where the bending load and the tension load which can be transmitted by the external
fitting convex portions 21 and the internal fitting convex portions 31 are decreased
by the cross-sectional defect when viewed in the axial direction. Accordingly, in
the joint structure 1 of a steel-pipe pile, it is not necessary to enlarge the external
fitting convex portions 21 and the internal fitting convex portions 31 by the cross-sectional
defect to withstand the predetermined bending load and tension load, and it is not
necessary to increase the number of steps of the external fitting step portion 29
and the internal fitting step portion 39 in the axial direction X. Accordingly, it
is possible to avoid a case where the machining cost and the cost of materials of
the joint structure between the lower steel-pipe pile 2 and the upper steel-pipe pile
3 are increased.
[0057] In the joint structure 1, since the external fitting convex portion 21 formed on
the first external fitting step portion 29a and the external fitting convex portion
21 formed on the second external fitting step portion 29b are provided at positions
which deviate in the axial direction X, the bending load and the tension load applied
to the external fitting convex portions 21 and the internal fitting convex portions
31 can be uniform in the circumferential direction Z. Accordingly, in the joint structure
1, it is possible to avoid a case where the bending load and the tension load are
concentrated on partial external fitting convex portions 21 and internal fitting convex
portions 31 in the circumferential direction Z. Therefore, in the joint structure
1, the loads transmitted from the external fitting convex portion 21 and the internal
fitting convex portion 31 to the main bodies of the lower steel-pipe pile 2 and the
upper steel-pipe pile 3 can be uniform in the circumferential direction Z, and thus,
increases in the plate thicknesses of the lower steel-pipe pile 2 and the upper steel-pipe
pile 3 can be avoided. Accordingly, it is possible to avoid a case where the costs
of materials of the joint structure between the lower steel-pipe pile 2 and the upper
steel-pipe pile 3 is increased.
[0058] Here, in the joint structure 1, in the first external fitting step portion 29a and
the first internal fitting step portion 39a, each of the external fitting convex portions
21 and the internal fitting convex portions 31 is formed in one step (one row), and
the plate thicknesses of the lower steel-pipe pile 2 and the upper steel-pipe pile
3 are sufficient if the plate has load bearing capacity with respect to the bending
load and the tension load by the one step. Meanwhile, in the second external fitting
step portion 29b and the second internal fitting step portion 39b, the number of steps
(the number of rows) of the external fitting convex portion 21 and the internal fitting
convex portion 31 increases, and it is necessary to set the plate thicknesses of the
lower steel-pipe pile 2 and the upper steel-pipe pile 3 according to the increase
in the number of steps. In the joint structure 1, the plate thicknesses of the lower
steel-pipe pile 2 and the upper steel-pipe pile 3 are thickened in stages from the
outer side (upper side) toward the inner side (lower side) in the axial direction
X of the lower steel-pipe pile 2 and from the outer side (lower side) toward the inner
side (upper side) in the axial direction X of the upper steel-pipe pile 3, and the
external fitting step portion 29 and the internal fitting step portion 39 are formed.
Accordingly, in the joint structure 1, the structure in which the plate thicknesses
of the lower steel-pipe pile 2 and the upper steel-pipe pile 3 increase in stages
according to the number of steps of the external fitting convex portions 21 and the
internal fitting convex portions 31 can be easily realized.
[0059] In addition, in the joint structure 1, the external fitting convex portions 21 formed
on the first external fitting step portion 29a and the external fitting convex portions
21 formed on the second external fitting step portion 29b are provided at positions
which deviate in the axial direction X. Accordingly, in the joint structure 1, even
when the bending load is applied to the portion at which the lower steel-pipe pile
2 and the upper steel-pipe pile 3 are connected together, the external fitting convex
portions 21 of either the first external fitting step portion 29a or the second external
fitting step portion 29b and the internal fitting convex portions 31 of either the
first internal fitting step portion 39a or the second internal fitting step portion
39b can be accurately disposed at the portions corresponding to the outermost edge
ends of the lower steel-pipe pile 2 and the upper steel-pipe pile 3 at which the tensile
stress is maximized. Therefore, in the joint structure 1, the bending load is accurately
applied to any of the external fitting convex portions 21 and any of the internal
fitting convex portions 31, and it is possible to avoid a case where the external
fitting end portion 20 of the lower steel-pipe pile 2 and the internal fitting end
portion 30 of the upper steel-pipe pile 3 are damaged.
[0060] In the first embodiment, the case is shown, in which the external fitting end portion
20 includes the plurality of step portions (first external fitting step portion 29a
and second external fitting step portion 29b), and the internal fitting end portion
30 includes the plurality of step portions (first internal fitting step portion 39a
and second internal fitting step portion 39b). However, for example, as shown in FIG.
18, each of the external fitting end portion 20 and the internal fitting end portion
30 may include one step portion (external fitting step portion 29 or internal fitting
step portion 39), and the external fitting convex portions 21 and the internal fitting
convex portions 31 may be formed at positions which deviate in the axial direction
X.
[0061] Also in this case, the cross-sectional defect does not occur when viewed in the axial
direction, and the loads transmitted from the external fitting convex portions 21
and the internal fitting convex portions 31 to the main bodies of the lower steel-pipe
pile 2 and the upper steel-pipe pile 3 can be uniform in the circumferential direction.
[0062] In addition, in this case, since the plurality of step portions are not formed on
the external fitting end portion 20 and the internal fitting end portion 30, compared
to the first embodiment, it is possible to decrease the machining costs.
[0063] In addition, in the first embodiment, the case is shown, in which the external fitting
convex portions 21 are formed in one step (one row) on each of the first external
fitting step portion 29a and the second external fitting step portion 29b and the
internal fitting convex portions 31 are formed in one step (one row) on each of the
first internal fitting step portion 39a and the second internal fitting step portion
39b. However, for example, as shown in FIG. 19, the external fitting convex portions
21 may be formed in two steps (two rows) on the first external fitting step portion
29a, and the external fitting convex portions 21 may be formed in one step (one row)
on the second external fitting step portion 29b.
[0064] Also in this case, the cross-sectional defect does not occur when viewed in the axial
direction, and the loads transmitted from the external fitting convex portions 21
and the internal fitting convex portions 31 to the main bodies of the lower steel-pipe
pile 2 and the upper steel-pipe pile 3 can be uniform in the circumferential direction.
[0065] In addition, in this case, compared to the first embodiment, the number of the external
fitting convex portions 21 and the internal fitting convex portions 31 can be increased,
and thus, the loads applied to one external fitting convex portion 21 and one internal
fitting convex portion 31 can be decreased.
[0066] Moreover, in FIG. 19, the case is shown, in which the external fitting convex portions
21 are formed in two steps (two rows) on the first external fitting step portion 29a
and the internal fitting convex portions 31 are formed in two steps (two rows) on
the first internal fitting step portion 39a. However, the external fitting convex
portions 21 and the internal fitting convex portions 31 may be formed in a plurality
of step portions (a plurality of rows) on the second external fitting step portion
29b and the second internal fitting step portion 39b.
[0067] As described above, from the viewpoint that the cross-sectional defect does not occur
when viewed in the axial direction, the external fitting convex portions 21 and the
external fitting groove portions 22 are formed in the plurality of rows in the axial
direction X, and among the plurality of rows adjacent to one another along the axial
direction X, in at least (one set of) two rows adjacent to each other, the external
fitting convex portions 21 of one row and the external fitting groove portions 22
of the other row may be formed to be adjacent to each other in the axis orthogonal
direction Y when viewed in the axial direction.
(Second Embodiment)
[0068] Next, a joint structure 100 of a steel-pipe pile according to a second embodiment
of the present invention will be described. Moreover, the same numeral references
are assigned to the same components as the above-described components, and descriptions
thereof are omitted below.
[0069] In the joint structure 100 of a steel-pipe pile according to the second embodiment,
as shown in FIG. 20, three external fitting step portions 29 (29a, 29b, and 29c) arranged
in the axial direction X of the lower steel-pipe pile 2 are provided on the external
fitting end portion 20. Moreover, three internal fitting step portions 39 (39a, 39b,
and 39c) arranged in the axial direction X of the upper steel-pipe pile 3 are provided
on the internal fitting end portion 30.
[0070] The plate thickness of the lower steel-pipe pile 2 is thickened in stages in the
axial direction X and the external fitting step portion 29 is formed so that the external
fitting convex portions 21 of the first external fitting step portion 29a in the outer
side (upper side) in the axial direction X of the lower steel-pipe pile 2, and the
external fitting groove portions 22 of the second external fitting step portion 29b
in the inner side (lower side) in the axial direction X of the lower steel-pipe pile
2 from the first external fitting step portion 29a have approximately the same thickness
in the axis orthogonal direction Y of the lower steel-pipe pile 2, and the external
fitting convex portions 21 of the second external fitting step portion 29b, and the
external fitting groove portions 22 of the third external fitting step portion 29c
in the inner side (lower side) in the axial direction X of the lower steel-pipe pile
2 from the second external fitting step portion 29b have approximately the same thickness
in the axis orthogonal direction Y of the lower steel-pipe pile 2.
[0071] The external fitting convex portions 21 formed on the first external fitting step
portion 29a and the external fitting convex portions 21 formed on the second external
fitting step portion 29b are provided at positions which deviate in the axial direction
X. In addition, the external fitting convex portions 21 formed on the second external
fitting step portion 29b and the external fitting convex portions 21 formed on the
third external fitting step portion 29c are provided at positions which deviate in
the axial direction X.
[0072] As shown in FIG. 21A, the external fitting convex portions 21 of the second external
fitting step portion 29b are formed at all positions adjacent to the external fitting
groove portions 22 formed on the first external fitting step portion 29a in the axis
orthogonal direction Y when viewed in the axial direction. In addition, the external
fitting convex portions 21 of the third external fitting step portion 29c are formed
at all positions adjacent to the external fitting groove portions 22 formed on the
second external fitting step portion 29b in the axis orthogonal direction Y when viewed
in the axial direction. Accordingly, the external fitting convex portions 21 of the
first external fitting step portion 29a and the external fitting convex portions 21
of the second external fitting step portion 29b are alternately formed without gaps
in the circumferential direction Z when viewed in the axial direction, and the external
fitting convex portions 21 of the second external fitting step portion 29b and the
external fitting convex portions 21 of the third external fitting step portion 29c
are alternately formed without gaps in the circumferential direction Z when viewed
in the axial direction.
[0073] In addition, the external fitting convex portions 21 are not limited to the above,
and as shown in FIG. 21B, the external fitting convex portions 21 of the second external
fitting step portion 29b may be formed at partial positions adjacent to the external
fitting groove portions 22 formed on the first external fitting step portion 29a in
the axis orthogonal direction Y when viewed in the axial direction, and the external
fitting convex portions 21 of the third external fitting step portion 29c may be formed
at partial positions adjacent to the external fitting groove portions 22 formed on
the second external fitting step portion 29b in the axis orthogonal direction Y when
viewed in the axial direction. At this time, the external fitting convex portions
21 of the first external fitting step portion 29a and the external fitting convex
portions 21 of the second external fitting step portion 29b are alternately formed
with gaps in the circumferential direction Z when viewed in the axial direction, and
the external fitting convex portions 21 of the second external fitting step portion
29b and the external fitting convex portions 21 of the third external fitting step
portion 29c are alternately formed with gaps in the circumferential direction Z when
viewed in the axial direction.
[0074] The plate thickness of the upper steel-pipe pile 3 is thickened in stages in the
axial direction X and the internal fitting step portion 39 is formed so that the internal
fitting groove portions 32 of the first internal fitting step portion 39a in the inner
side (upper side) in the axial direction X of the upper steel-pipe pile 3, and the
internal fitting convex portions 31 of the second internal fitting step portion 39b
in the outer side (lower side) in the axial direction X of the upper steel-pipe pile
3 from the first internal fitting step portion 39a have approximately the same thickness
in the axis orthogonal direction Y of the upper steel-pipe pile 3, and the internal
fitting groove portions 32 of the second internal fitting step portion 39b, and the
internal fitting convex portions 31 of the third internal fitting step portion 39c
in the outer side (lower side) in the axial direction X from the second internal fitting
step portion 39b have approximately the same thickness in the axis orthogonal direction
Y.
[0075] The internal fitting convex portions 31 formed on the first internal fitting step
portion 39a and the internal fitting convex portions 31 formed on the second internal
fitting step portion 39b are provided at positions which deviate in the axial direction
X. In addition, the internal fitting convex portions 31 formed on the second internal
fitting step portion 39b and the internal fitting convex portions 31 formed on the
third internal fitting step portion 39c are provided at positions which deviate in
the axial direction X.
[0076] As shown in FIG. 22A, the internal fitting convex portions 31 of the second internal
fitting step portion 39b are formed at all positions adjacent to the internal fitting
groove portions 32 formed on the first internal fitting step portion 39a in the axis
orthogonal direction Y when viewed in the axial direction. In addition, the internal
fitting convex portions 31 of the third internal fitting step portion 39c are formed
at all positions adjacent to the internal fitting groove portions 32 formed on the
second internal fitting step portion 39b in the axis orthogonal direction Y when viewed
in the axial direction. Accordingly, the internal fitting convex portions 31 of the
first internal fitting step portion 39a and the internal fitting convex portions 31
of the second internal fitting step portion 39b are alternately formed without gaps
in the circumferential direction Z when viewed in the axial direction, and the internal
fitting convex portions 31 of the second internal fitting step portion 39b and the
internal fitting convex portions 31 of the third internal fitting step portion 39c
are alternately formed without gaps in the circumferential direction Z when viewed
in the axial direction.
[0077] In addition, the internal fitting convex portions 31 are not limited to the above,
and as shown in FIG. 22B, the internal fitting convex portions 31 of the second internal
fitting step portion 39b may be formed at partial positions adjacent to the internal
fitting groove portions 32 formed on the first internal fitting step portion 39a in
the axis orthogonal direction Y when viewed in the axial direction. Moreover, the
internal fitting convex portions 31 of the third internal fitting step portion 39c
may be formed at partial positions adjacent to the internal fitting groove portions
32 formed on the second internal fitting step portion 39b in the axis orthogonal direction
Y when viewed in the axial direction. At this time, in the internal fitting convex
portions 31, the internal fitting convex portions 31 of the first internal fitting
step portion 39a and the internal fitting convex portions 31 of the second internal
fitting step portion 39b are alternately formed with gaps in the circumferential direction
Z when viewed in the axial direction, and the internal fitting convex portions 31
of the second internal fitting step portion 39b and the internal fitting convex portions
31 of the third internal fitting step portion 39c are alternately formed with gaps
in the circumferential direction Z when viewed in the axial direction.
[0078] Next, a method for connecting the lower steel-pipe pile 2 and the upper steel-pipe
pile 3 together using the joint structure 100 of a steel-pipe pile according to the
second embodiment will be described in detail with reference to the drawings.
[0079] First, the internal fitting end portion 30 of the upper steel-pipe pile 3 is inserted
into the external fitting end portion 20 of the lower steel-pipe pile 2 in the axial
direction X. Accordingly, as shown in FIGS. 23 and 24, the internal fitting convex
portions 31 of the first internal fitting step portion 39a pass through the external
fitting groove portions 22 of the first external fitting step portion 29a and abut
the lower end surface of the external fitting engagement groove 23 of the first external
fitting step portion 29a. Moreover, the internal fitting convex portions 31 of the
second internal fitting step portion 39b pass through the external fitting groove
portions 22 of the second external fitting step portion 29b and abut the lower end
surface of the external fitting engagement groove 23 of the second external fitting
step portion 29b. In addition, the internal fitting convex portions 31 of the third
internal fitting step portion 39c pass through the external fitting groove portions
22 of the third external fitting step portion 29c and abut the lower end surface of
the external fitting engagement groove 23 of the third external fitting step portion
29c.
[0080] Here, in the joint structure 100, the external fitting convex portions 21 of the
first external fitting step portion 29a and the external fitting groove portions 22
of the second external fitting step portion 29b are formed to all have approximately
the same thicknesses in the axis orthogonal direction Y of the lower steel-pipe pile
2, and the internal fitting groove portions 32 of the first internal fitting step
portion 39a and the internal fitting convex portions 31 of the second internal fitting
step portion 39b are formed to all have approximately the same thicknesses in the
axis orthogonal direction Y of the upper steel-pipe pile 3. In addition, the external
fitting convex portions 21 of the second external fitting step portion 29b and the
external fitting groove portions 22 of the third external fitting step portion 29c
are formed to all have approximately the same thicknesses in the axis orthogonal direction
Y of the lower steel-pipe pile 2, and the internal fitting groove portions 32 of the
second internal fitting step portion 39b and the internal fitting convex portions
31 of the third internal fitting step portion 39c are formed to all have approximately
the same thicknesses in the axis orthogonal direction Y of the upper steel-pipe pile
3. Accordingly, the internal fitting end portion 30 of the upper steel-pipe pile 3
is inserted into the external fitting end portion 20 of the lower steel-pipe pile
2 without interference between the internal fitting convex portions 31 of the third
internal fitting step portion 39c and the external fitting convex portions 21 of the
first external fitting step portion 29a and the second external fitting step portion
29b, and without interference between the internal fitting convex portions 31 of the
second internal fitting step portion 39b and the external fitting convex portions
21 of the first external fitting step portion 29a.
[0081] At this time, in the joint structure 100, as shown in FIG. 24, in the state where
the internal fitting end portion 30 of the upper steel-pipe pile 3 is inserted into
the external fitting end portion 20 of the lower steel-pipe pile 2, the gap d having
a predetermined height in the axial direction X is formed between the tip portion
28 of the external fitting end portion 20 and the internal fitting edge 38 of the
internal fitting end portion 30.
[0082] Next, in the joint structure 100, as shown in FIG. 25, the lower steel-pipe pile
2 and the upper steel-pipe pile 3 are relatively rotated in the circumferential direction
Z around the axis. Accordingly, as shown in FIGS. 26 and 27, the internal fitting
convex portions 31 move in the circumferential direction Z in the external fitting
engagement groove 23 to portions under the external fitting convex portions 21. Moreover,
the internal fitting convex portions 31 engage with the external fitting convex portions
21 in the axial direction X, and the external fitting end portion 20 of the lower
steel-pipe pile 2 and the internal fitting end portion 30 of the upper steel-pipe
pile 3 are fitted together.
[0083] At this time, in the joint structure 100, as shown in FIG. 27, the third tapered
portion 31a (refer to FIG. 9) abuts the first tapered portion 21a (refer to FIG. 5),
the fourth tapered portion 31 b (refer to FIG. 9) abuts the second tapered portion
23 a (refer to FIG. 5), and thus, the internal fitting convex portion 31 moves in
the circumferential direction Z on the external fitting engagement groove 23. Accordingly,
the lower steel-pipe pile 2 and the upper steel-pipe pile 3 approach each other in
the axial direction X, and thus, the tip portion 28 of the external fitting end portion
20 and the internal fitting edge 38 of the internal fitting end portion 30 abut each
other to fill the gap d.
[0084] Similar to the first embodiment, as described above, in the second embodiment, in
the state where the external fitting convex portions 21 and the internal fitting convex
portions 31 engage with each other in the axial direction X, the tip portion 28 of
the external fitting end portion 20 and the internal fitting edge 38 of the internal
fitting end portion 30 abut each other to fill the gap d. Accordingly, whether or
not the external fitting end portion 20 of the lower steel-pipe pile 2 and the internal
fitting end portion 30 of the upper steel-pipe pile 3 are completely fitted together
can be determined by visually confirming the gap d from the outside.
[0085] In addition, similar to the first embodiment, also in the second embodiment, after
the external fitting end portion 20 of the lower steel-pipe pile 2 and the internal
fitting end portion 30 of the upper steel-pipe pile 3 are fitted together, the feeler
gauge abuts the gap d, and the fitting between the external fitting end portion 20
and the internal fitting end portion 30 may be confirmed according to whether or not
the feeler gauge passes through the gap d. In this case, compared to the above-described
visual confirmation method, whether or not the external fitting end portion 20 and
the internal fitting end portion 30 are fitted together can be more accurately determined.
[0086] Moreover, similar to the first embodiment, in the second embodiment, as shown in
FIG. 27, the third tapered portion 31a (refer to FIG. 9) abuts the first tapered portion
21a (refer to FIG. 5), and the fourth tapered portion 31b (refer to FIG. 9) abuts
the second tapered portion 23a (refer to FIG. 5), and thus, the internal fitting convex
portion 31 of the upper steel-pipe pile 3 can smoothly move in the circumferential
direction Z on the external fitting engagement groove 23 of the lower steel-pipe pile
2. Accordingly, the external fitting end portion 20 of the lower steel-pipe pile 2
and the internal fitting end portion 30 of the upper steel-pipe pile 3 can be easily
fitted together. In addition, the internal fitting convex portion 31 is locked to
the locking portion 23b (refer to FIG. 5) of the external fitting engagement groove
23, and thus, it is possible to prevent the upper steel-pipe pile 3 from being rotated
more than necessary.
[0087] In the joint structure 100 of a steel-pipe pile according to the second embodiment,
in the state where the external fitting end portion 20 of the lower steel-pipe pile
2 and the internal fitting end portion 30 of the upper steel-pipe pile 3 are fitted
together, the internal fitting convex portions 31 of the first internal fitting step
portion 39a engage with the external fitting convex portions 21 of the first external
fitting step portion 29a, the internal fitting convex portions 31 of the second internal
fitting step portion 39b engage with the external fitting convex portions 21 of the
second external fitting step portion 29b, and the internal fitting convex portions
31 of the third internal fitting step portion 39c engage with the external fitting
convex portions 21 of the third external fitting step portion 29c. In addition, the
bending load and the tension load are transmitted to the main body of the steel-pipe
pile. Moreover, the external fitting convex portions 21 of the first external fitting
step portion 29a and the external fitting convex portions 21 of the second external
fitting step portion 29b are provided at positions which deviate in the axial direction
X, and the external fitting convex portions 21 of the second external fitting step
portion 29b and the external fitting convex portions 21 of the third external fitting
step portion 29c are provided at positions which deviate in the axial direction X.
Accordingly, in the joint structure 100 of a steel-pipe pile according to the second
embodiment, and the lower steel-pipe pile 2 and the upper steel-pipe pile 3 can be
connected together without the cross-sectional defect when viewed in the axial direction.
[0088] Therefore, similar to the first embodiment, also in the second embodiment, in the
state where the external fitting end portion 20 of the lower steel-pipe pile 2 and
the internal fitting end portion 30 of the upper steel-pipe pile 3 are fitted together,
it is possible to avoid a case where the bending load and the tension load which can
be transmitted by the external fitting convex portions 21 and the internal fitting
convex portions 31 are decreased by the cross-sectional defect when viewed in the
axial direction. Accordingly, it is not necessary to enlarge the external fitting
convex portions 21 and the internal fitting convex portions 31 by the cross-sectional
defect to withstand predetermined bending load and tension load, and it is not necessary
to increase the number of steps of the external fitting step portion 29 and the internal
fitting step portion 39 in the axial direction X, and thus, it is possible to avoid
a case where the machining cost and the cost of materials of the joint structure of
a steel-pipe pile are increased.
[0089] In the second embodiment, the external fitting convex portion 21 of the first external
fitting step portion 29a and the external fitting convex portion 21 of the second
external fitting step portion 29b are provided at positions which deviate in the axial
direction X, the external fitting convex portion 21 of the second external fitting
step portion 29b and the external fitting convex portion 21 of the third external
fitting step portion 29c are provided at positions which deviate in the axial direction
X, and thus, the bending load and the tension load applied to the external fitting
convex portions 21 and the internal fitting convex portions 31 can be uniform in the
circumferential direction Z. Accordingly, it is possible to avoid a case where the
bending load and the tension load are concentrated on partial external fitting convex
portions 21 and internal fitting convex portions 31 in the circumferential direction
Z. Therefore, also in the second embodiment, the loads transmitted from the external
fitting convex portion 21 and the internal fitting convex portion 31 to the main bodies
of the lower steel-pipe pile 2 and the upper steel-pipe pile 3 can be uniform in the
circumferential direction Z, and thus, increases in the plate thicknesses of the lower
steel-pipe pile 2 and the upper steel-pipe pile 3 can be avoided. Accordingly, it
is possible to avoid a case where the cost of materials of the joint structure between
the lower steel-pipe pile 2 and the upper steel-pipe pile 3 is increased.
[0090] Here, in the first external fitting step portion 29a and the first internal fitting
step portion 39a, the external fitting convex portions 21 and the internal fitting
convex portions 31 are formed in one step (one row), and the plate thicknesses of
the lower steel-pipe pile 2 and the upper steel-pipe pile 3 are sufficient if the
plate has load bearing capacity with respect to the bending load and the tension load
by the one step. Meanwhile, the number of steps (the number of rows) of the external
fitting convex portion 21 and the internal fitting convex portion 31 increases in
the second external fitting step portion 29b and the second internal fitting step
portion 39b, the number of steps of the external fitting convex portion 21 and the
internal fitting convex portion 31 increases in the third external fitting step portion
29c and the third internal fitting step portion 39c, and thus, it is necessary to
set the plate thicknesses of the lower steel-pipe pile 2 and the upper steel-pipe
pile 3 according to the increase in the number of steps. In the joint structure 100,
the plate thicknesses of the lower steel-pipe pile 2 and the upper steel-pipe pile
3 are thickened in stages from the outer side (upper side) toward the inner side (lower
side) in the axial direction X of the lower steel-pipe pile 2 and from the outer side
(lower side) toward the inner side (upper side) in the axial direction X of the upper
steel-pipe pile 3, and the external fitting step portion 29 and the internal fitting
step portion 39 are formed. Accordingly, also in the second embodiment, the structure
in which the plate thicknesses of the lower steel-pipe pile 2 and the upper steel-pipe
pile 3 increase in stages according to the number of steps of the external fitting
convex portions 21 and the internal fitting convex portions 31 can be easily realized.
[0091] In addition, in the joint structure 100, the external fitting convex portions 21
of the first external fitting step portion 29a and the external fitting convex portions
21 of the second external fitting step portion 29b are provided at positions which
deviate in the axial direction X, and the external fitting convex portions 21 of the
second external fitting step portion 29b and the external fitting convex portions
21 of the third external fitting step portion 29c are provided at positions which
deviate in the axial direction X. Accordingly, even when the bending load is applied
to the portion at which the lower steel-pipe pile 2 and the upper steel-pipe pile
3 are connected together, the external fitting convex portions 21 of any of the first
external fitting step portion 29a, the second external fitting step portion 29b, and
the third external fitting step portion 29c, and the internal fitting convex portions
31 of any of the first internal fitting step portion 39a, the second internal fitting
step portion 39b, and the third internal fitting step portion 39c can be accurately
disposed at the portions corresponding to the outermost edge ends of the lower steel-pipe
pile 2 and the upper steel-pipe pile 3 at which the tensile stress is maximized. Therefore,
also in the second embodiment, the bending load is accurately applied to any of the
external fitting convex portions 21 and any of the internal fitting convex portions
31, and it is possible to avoid a case where the external fitting end portion 20 of
the lower steel-pipe pile 2 and the internal fitting end portion 30 of the upper steel-pipe
pile 3 are damaged.
[0092] In the second embodiment, the case is shown, in which the number of steps in each
of the external fitting step portion 29 and the internal fitting step portion 39 is
three, the external fitting convex portions 21 of the first external fitting step
portion 29a and the external fitting convex portions 21 of the second external fitting
step portion 29b are provided at positions which deviate in the axial direction X,
and the external fitting convex portions 21 of the second external fitting step portion
29b and the external fitting convex portions 21 of the third external fitting step
portion 29c are provided at positions which deviate in the axial direction X.
[0093] However, the present invention is not limited to the above, and for example, the
external fitting convex portions 21 of the first external fitting step portion 29a
and the external fitting convex portions 21 of the second external fitting step portion
29b may be provided at positions which deviate in the axial direction X, and the external
fitting convex portions 21 of the second external fitting step portion 29b and the
external fitting convex portions 21 of the third external fitting step portion 29c
are provided at positions matched in the axial direction X. Also in this case, the
cross-sectional defect does not occur when viewed in the axial direction, and the
loads transmitted from the external fitting convex portions 21 and the internal fitting
convex portions 31 to the main body of a steel-pipe pile can be uniform in the circumferential
direction.
[0094] Accordingly, in the plurality of external fitting step portions 29 formed on the
external fitting end portion 20 along the axial direction X, the external fitting
convex portions 21 of the external fitting step portion 29 positioned at the outermost
side (upper side) in the axial direction X and the external fitting convex portions
21 of at least one external fitting step portion 29 positioned at the inner side (lower
side) in the axial direction X may be provided at positions which deviate in the axial
direction X. In other words, in at least (one set of) the external fitting step portions
29 adjacent to each other among the plurality of external fitting step portions 29
adjacent to one another, the external fitting convex portions 21 of one external fitting
step portion 29 and the external fitting groove portion 22 of the other external fitting
step portion 29 may be provided to be adjacent in the axis orthogonal direction Y
when viewed in the axial direction X.
[0095] The first embodiment shows the case in which the number of steps in each of the external
fitting step portion 29 and the internal fitting step portion 39 is two, and the second
embodiment shows the case in which the number of steps in each of the external fitting
step portion 29 and the internal fitting step portion 39 is three. However, preferably,
the number of steps is two. When the number of steps is increased, the thicknesses
of the tip portions (the outer side in the axial direction X) of the external fitting
step portion and the internal fitting step portion in the steel-pipe pile are inevitably
decreased. The damage by the loads easily occurs as the thickness of the tip portion
is decreased. As a result, the joint structure is easily damaged. On the other hand,
if the number of steps is two, the thicknesses in the inner sides in the axial direction
X can be thinned while the thicknesses of the tip portions (the outer sides in the
axial direction X) of the external fitting step portion and the internal fitting step
portion are maintained in certain thicknesses or more. Accordingly, the increase in
the cost of materials due to the increase in the plate thickness of the steel-pipe
pile can be prevented.
[0096] As the above, embodiments of the present invention are described in detail. However,
the above-described embodiments are only specific examples for embodying the present
invention, and the technical scope of the present invention should not be interpreted
as being limited by the embodiments.
[0097] For example, a joint structure may be adopted in which the lower steel-pipe pile
2 (first steel-pipe pile) includes the internal fitting end portion 30, and the upper
steel-pipe pile 3 (second steel-pipe pile) includes the external fitting end portion
20.
[0098] In addition, a joint structure may be adopt, which includes a rotation prevention
unit (not shown) for preventing reverse rotations of the lower steel-pipe pile 2 and
the upper steel-pipe pile 3 connected together in the axial direction X. For example,
as the rotation prevention unit, in the state where the lower steel-pipe pile 2 and
the upper steel-pipe pile 3 are connected together in the axial direction X, a screw
may be inserted into the lower steel-pipe pile 2 to prevent the reverse rotation.
[0099] Moreover, the external fitting step portion 29 having any number of steps may be
arranged in the axial direction X of the lower steel-pipe pile 2 on the external fitting
end portion 20, and the internal fitting step portion 39 having any number of steps
may be arranged in the axial direction X of the upper steel-pipe pile 3 on the internal
fitting end portion 30.
[Industrial Applicability]
[0100] It is possible to provide a joint structure of a steel-pipe pile and a steel-pipe
pile in which an increase in labor for rotation of a steel-pipe pile at a work site
is prevented, an excessive increase in a plate thickness of the steel-pipe pile is
avoided, and there is no concern of damage even when the bending load is applied.
[Brief Description of the Reference Symbols]
[0101]
1: joint structure of steel-pipe pile
2: lower steel-pipe pile (first steel-pipe pile)
20: external fitting end portion
21: external fitting convex portion
21a: first tapered portion
22: external fitting groove portion
23: external fitting engagement groove
23a: second tapered portion
23b: locking portion
28: tip portion
29: external fitting step portion
29a: first external fitting step portion
29b: second external fitting step portion
29c: third external fitting step portion
3: upper steel-pipe pile (second steel-pipe pile)
30: internal fitting end portion
31: internal fitting convex portion
31a: third tapered portion
31b: fourth tapered portion
32: internal fitting groove portion
33: internal fitting engagement groove
38: internal fitting edge
39: internal fitting step portion
39a: first internal fitting step portion
39b: second internal fitting step portion
39c: third internal fitting step portion
100: joint structure of steel-pipe pile
X: axial direction
Y: axis orthogonal direction
Z: circumferential direction
d: gap
h: height of tapered portion