JP4772925B2 - Steel sheet pile - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a steel sheet pile, and more particularly to a steel sheet pile used when building a wall structure such as a river revetment, retaining wall and earth retaining in the field of civil engineering construction. This application claims priority based on Japanese Patent Application No. 2008-222562 filed in Japan on August 29, 2008, the contents of which are incorporated herein by reference.

  A steel sheet pile manufactured by hot rolling includes a flange, a pair of webs disposed at both ends of the flange, and a joint disposed at the tip side of the web, and is generally a U-shaped steel sheet pile or a hat shape. It is called a steel sheet pile. A plurality of steel sheet piles are placed on the ground so as to be connected to each other, and a wall structure such as a river revetment, retaining wall and earth retaining is constructed. The wall structure is held vertically by resisting the earth pressure acting from the back of the wall structure due to the horizontal pressure by the ground applied to the base. Therefore, the steel sheet pile is required to have a rigidity that can sufficiently withstand the load that acts during placement and use. For the purpose of preventing buckling of a steel sheet that receives a compressive force such as a flange constituting a steel sheet pile, the width dimension is limited according to the thickness dimension of the steel sheet. For example, the road bridge specifications specify that the width-thickness ratio (b / t) of the width dimension (b) to the thickness dimension (t) of the steel plate is b / t ≦ 48.

However, in recent years, in order to improve the workability at the time of placing the steel sheet pile, there is an increasing demand for a steel sheet pile composed of a flange having a larger width-thickness ratio. For example, a wide steel sheet pile with a longer width than the conventional one so that a wall structure can be constructed with a smaller number of steel sheet piles, or a thin wall with a thinner thickness than the conventional one to reduce weight alone. Steel sheet piles are required.
In order to provide such a wide or thin steel sheet pile with sufficient rigidity against buckling, it is necessary to take some measures for buckling. For example, a technique for improving the rigidity by installing protrusions on both sides of a flange of a U-shaped steel sheet pile at equal intervals has been proposed (see Patent Document 1).

JP 2004-332517 A

  However, in the steel sheet pile described in Patent Document 1, since a large number of protrusions are installed on both sides of the flange, the surface area of the flange increases, and the frictional resistance of the flange surface increases when it is placed in the adhesive ground. To do. For this reason, there is a problem that the placing speed is lowered and sufficient workability improvement cannot be obtained even if the width-thickness ratio is increased.

  An object of the present invention is to provide a steel sheet pile having sufficient rigidity against buckling and excellent workability.

The steel sheet pile of one aspect of the present invention includes a sheet pile main body portion and a joint portion formed on both side edges of the sheet pile main body portion, and at least a part of the sheet pile main body portion has a thickness dimension. The width-thickness ratio (b / t) of the width dimension (b) to (t) is a wide flat plate formed so as to be 48 or more and 96 or less, and the sheet pile main body portion includes a first flange and the first flange. A pair or one web continuous to both or one side edge of the flange, and a pair or one second flange extending outwardly in parallel with the first flange from the pair or one web tip edge; The web is the wide flat plate, and one surface of the wide flat plate of the sheet pile main body portion is provided with a single protrusion extending along the longitudinal direction at the center of the wide flat plate , The ratio of the thickness (t) to the distance between the side edge of the wide flat plate and the protrusion is 48 or more. The neutral axis of the wall structure when the sheet pile main body portion constitutes a wall structure bisects the area of the ridge portion, and the ridge portion is a cross-sectional shape orthogonal to the longitudinal direction. Is a substantially rectangular shape, a substantially semicircular shape, a substantially semi-elliptical shape, or a substantially triangular shape, and further, the cross-sectional area (A) of the protrusion in the cross-sectional shape orthogonal to the longitudinal direction and the The cross-sectional secondary moment (I) of the ridge portion with respect to one surface is provided so as to be within the range defined by the following equations (1) and (2).
A ≧ b · t / 20 (1)
^{I ≧ b · t 3/11} · γ ··· (2)
Here, γ = 1/2 · (8 (1 + 2δ) −1) ² −1
δ = A / bt

According to this configuration, the protrusion provided on the wide flat plate functions as a stiffening material for buckling reinforcement. That is, compared to a flange without a ridge, the second moment of section of the entire sheet pile main body including the ridge increases by the amount of the ridge, so the buckling stress of the entire sheet pile main body Becomes larger and buckling is less likely to occur. Therefore, it is possible to provide sufficient rigidity against buckling at the time of placing and in service.
Further, if the width-thickness ratio (b / t) of the wide flat plate is within the range represented by 48 ≦ b / t ≦ 96, it is only necessary to form one protrusion on the wide flat plate, An effect of preventing bending is obtained, and there is no need to provide a plurality of protrusions as in the conventional case. Therefore, the frictional resistance due to the protruding portion at the time of placing does not increase significantly, and a reduction in placing speed can be prevented.
Moreover, a wall structure can be constructed with a smaller number of sheets by using a wide steel sheet pile having a longer plate width than before. Alternatively, it is possible to reduce the weight of the steel sheet by using a thin steel sheet pile having a smaller thickness than the conventional one. In addition, the driving force can be increased to reduce the number of times of driving and shorten the construction time. As described above, excellent workability can be exhibited.
Further, according to the above configuration, since the protrusion is located on the neutral axis of the wall structure, even if the protrusion is provided, the neutral axis is not displaced, and the conventional steel is not accompanied by a large design change. A wall structure can be constructed in the same manner as when a sheet pile is used.

In the steel sheet pile of one aspect of the present invention, the ridge portion may be integrally formed on the wide flat plate.
According to this configuration, it is not necessary to increase the number of steps for forming the ridges on the flat plate, compared to the case where the ridges are welded later, and an increase in manufacturing costs can be suppressed, and an inexpensive steel sheet pile can be used. Can be provided.
Moreover, when the rigidity of a flat plate is improved by welding a rib or the like to the flat plate later, there is a problem that thermal deformation due to welding heat occurs on a thin flat plate having a large width-thickness ratio. On the other hand, when the ridge portion is integrally formed with the sheet pile main body portion by hot rolling, the ridge portion can be formed without being affected by thermal deformation.
Incidentally, when a plurality of protrusions are formed on one flat plate by hot rolling, there is a problem that a burden on the rolling roller is increased. According to the present invention, the effect of preventing the buckling of the steel sheet pile can be obtained only by forming one ridge portion, and therefore, an increase in roll load when manufacturing by hot rolling can be suppressed.

  According to the steel sheet pile of the present invention, the provision of a protrusion having a predetermined shape along the longitudinal direction on a wide flat plate has sufficient rigidity against buckling and has workability. Can be improved.

It is a cross-sectional view showing the U-shaped steel sheet pile according to the first embodiment of the present invention. It is a cross-sectional view which expands and shows a part of U-shaped steel sheet pile of the said embodiment. It is a cross-sectional view which shows the wall structure comprised using the U-shaped steel sheet pile of the said embodiment. It is a cross-sectional view which shows the U-shaped steel sheet pile which concerns on the modification of the said embodiment. FIG. 5A is a cross-sectional view showing a hat-shaped steel sheet pile according to the second embodiment, and FIG. 5B is a cross-sectional view showing a hat-shaped steel sheet pile according to the third embodiment. FIG. 6A is a cross-sectional view showing a Z-shaped steel sheet pile according to the fourth embodiment, and FIG. 6B is a cross-sectional view showing a linear steel sheet pile according to the fifth embodiment. It is a cross-sectional view which shows the U-shaped steel sheet pile which concerns on the modification of this invention.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.
In the second and subsequent embodiments, the same constituent members as those in the first embodiment and the constituent members having the same functions are denoted by the same reference numerals as those in the first embodiment, and the descriptions thereof are omitted. Omit or simplify.

[First Embodiment]
FIG. 1 is a cross-sectional view showing a steel sheet pile (U-shaped steel sheet pile) according to the first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a part of the U-shaped steel sheet pile. FIG. 3 is a cross-sectional view showing a wall structure constructed by combining a plurality of U-shaped steel sheet piles.

  In FIG. 1, a U-shaped steel sheet pile 10 is formed on both side edges of the sheet pile main body portion 11 formed from three long flat plates (flange 12 and a pair of webs 13) and the sheet pile main body portion 11. And a pair of joint portions 14 formed. Hereinafter, in FIG. 1, the direction perpendicular to the plane of the paper is the longitudinal direction of the flat plate, the direction parallel to the plane of the flat plate and perpendicular to the longitudinal direction is the width direction of the flat plate, and the direction perpendicular to the longitudinal direction and the width direction is the thickness of the flat plate. This is called the direction.

  The sheet pile main body 11 has a flange 12 located in the center and a pair of webs 13 formed continuously at both side edges in the width direction of the flange 12, and has a substantially U-shaped cross-sectional shape. I have. The flange 12 and the pair of webs 13 are integrally formed by hot rolling. That is, the flange 12 forms the bottom portion of the substantially U-shaped sheet pile main body portion 12, and the pair of webs 13 forms both side portions of the substantially U-shaped sheet pile main body portion 12. A joint portion 14 is formed in a bowl shape on the tip side of the web 13.

FIG. 2 is an enlarged cross-sectional view of the flange 12.
As shown in FIG. 2, the length of the flange 12 that is orthogonal to the longitudinal direction (that is, along the width direction) is the width dimension b of the flange 12. The thickness dimension t and the width dimension b are set such that the width-thickness ratio (b / t) of the width dimension b to the thickness dimension t along the thickness direction of the flange 12 is in the range of 48 or more and 96 or less. Is set. In the present embodiment, the flange 12 constitutes the wide flat plate of the present invention.

  At the approximate center in the width direction of the flange 12, a single protrusion that protrudes outward from the outer surface (the surface opposite to the inner surface of the substantially U-shaped recess) and extends along the longitudinal direction. A portion 15 is formed. In other words, as shown in FIG. 3, the protruding portion 15 is formed by combining a plurality of U-shaped steel sheet piles 10 out of either one of the front and back surfaces of the flange 12. It is provided on the surface opposite to the neutral axis P.

When the sheet pile main body 11 is manufactured by hot rolling, the protrusion 15 is integrally formed with the flange 12 and has a substantially rectangular cross-sectional shape perpendicular to the longitudinal direction.
As shown in FIG. 2, in the ridge portion 15, the length dimension in the protruding direction (thickness direction) from the outer surface of the flange 12 is the cross-sectional protruding dimension h of the ridge portion 15. The length dimension along the width direction is the width dimension w of the protrusion 15.
The protrusion 15 has a cross-sectional area A in a cross-sectional shape orthogonal to the longitudinal direction and a cross-sectional secondary moment I based on the surface on the front side of the flange defined by the following expressions (3) and (4). It is provided to be within the specified range. That is, the cross-sectional shape of the protrusion 15 is set within a range that satisfies both the expressions (3) and (4). The following formula is set to prevent local buckling in members subjected to compressive stress based on the Road Bridge Specification / Description (Japan Road Association). γ is a rigidity ratio of the protrusion 15 to the wide flat plate (the flange 12 in FIG. 2), and δ represents a cross-sectional area ratio in a cross-sectional shape orthogonal to the longitudinal direction of the protrusion 15 to the wide flat plate.
A ≧ b · t / 20 (3)
^{I ≧ b · t 3/11} · γ ··· (4)
Here, γ = 1/2 · (8 (1 + 2δ) −1) ² −1
δ = A / bt

  As shown in Expression (3), the cross-sectional area A of the ridge 15 is set to be 5% or more of the cross-sectional area (b · t) of the flange 12 alone. Further, as shown in the equation (4), the lower limit value of the sectional secondary moment I of the ridge portion 15 is set by the width dimension b and the thickness dimension t of the flange 12 and the sectional area A of the ridge portion 15. It is a value.

Further, as indicated by a solid line in FIG. 2, in order to suppress the weight per cross section of the ridge portion 15, it is preferable to suppress the width dimension w of the ridge portion 15 to be twice or less the cross-sectional protrusion dimension h. More preferably, the width dimension w should be suppressed to be equal to or less than the cross-sectional protrusion dimension h. FIG. 2 shows a ridge portion 15A having a width dimension w equal to the cross-sectional projection dimension h by a two-dot chain line. More preferably, the width dimension w should be suppressed to ½ times or less of the cross-sectional protrusion dimension h shown in the following formula (5). FIG. 2 shows another protrusion 15B having a width w that is ½ times the cross-sectional protrusion h by another two-dot chain line.
w ≦ h / 2 (5)

Table 1 shows specific examples of the cross-sectional protrusion dimension h and the width dimension w of the protrusion 15 as described above, using a wide flat plate of b = 480 mm and t = 10 mm as an example. In this wide flat plate, the value of b · t / 20 in the formula (3) is 240, whereas the protrusion 15 has a sectional area A of 240 mm ² or more, which satisfies the formula (3). is doing. As shown in the table below, the combinations of the cross-sectional protrusion dimension h and the width dimension w such as h = 80, w = 40 or h = 85, w = 11 or h = 90, w = 8 are all expressed by the formula (3). And (4) is satisfy | filled and also Formula (5) is satisfy | filled.

Here, the U-shaped steel sheet pile of the modification of this embodiment is demonstrated based on FIG.
FIG. 4 is a cross-sectional view showing a U-shaped steel sheet pile 10A according to a modification. In the U-shaped steel sheet pile 10 </ b> A, the ridge portion 15 is formed on the back surface of the flange 12 (the inner surface of the substantially U-shaped recess). Thus, as a steel sheet pile of this invention, the protrusion part should just be provided in the surface of either the front or back of the flange 12. FIG.

According to this embodiment, the following effects can be achieved.
(1) The protrusion 15 provided on the flange 12 functions as a stiffener for buckling reinforcement. That is, since the secondary moment of inertia I of the entire flange 12 including the ridge 15 is increased by the amount of the ridge 15 compared to the flange without the ridge, the seat of the sheet pile main body 11 is The bending stress is increased, and buckling is less likely to occur. Therefore, it is possible to provide sufficient rigidity against buckling at the time of placing and in service.

(2) If the width-thickness ratio (b / t) of the flange 12 is within the range of 48 ≦ b / t ≦ 96, the U-shaped steel sheet pile 10 can be formed only by forming one protrusion 15 on the flange 12. The effect of preventing buckling can be obtained, and there is no need to provide a plurality of protrusions on a single flange as in the prior art. Therefore, the frictional resistance is not significantly increased by the protrusion 15 at the time of placing, and a reduction in placing speed can be prevented.

(3) Even if the U-shaped steel sheet pile 10 having a wider width b than the conventional flange 12 is formed, sufficient rigidity against buckling can be provided, so that a smaller number of U-shaped steel sheet piles can be provided. 10, the wall structure 1 can be constructed, and the workability is improved.

(4) Even if the thin U-shaped steel sheet pile 10 having a thickness t smaller than that of the conventional flange 12 is formed, sufficient rigidity against buckling can be provided. The weight can be reduced, and the workability is improved.

(5) The driving force at the time of construction can be increased to reduce the number of times of placing, shortening the construction time, and the workability can be improved.
(6) Moreover, since the protrusion 15 is formed in the flange 12, the bending rigidity of the sheet pile main body 11 is increased, and horizontal vibration at the time of placing can be suppressed.

(7) Since the ridge portion 15 is integrally formed with the sheet pile main body portion 11 by hot rolling, the ridge portion 15 is provided on the flange 12 as compared with the case where the ridge portion 15 is welded to the flange 12 later. It is not necessary to increase the number of steps for forming, and an increase in manufacturing cost can be suppressed.

(8) When the flange 12 is welded to the flange 12 by retrofitting to improve the rigidity of the flange 12, the thin flange 12 having a large width-thickness ratio (b / t) undergoes thermal deformation due to welding heat. There is a problem of end. On the other hand, in this embodiment, since the protrusion part 15 is integrally formed with the sheet pile main-body part 11 by hot rolling, the protrusion part 15 can be formed without being influenced by thermal deformation.

(9) When a plurality of protrusions are formed on one flange 12 by hot rolling, there is a problem that a burden on the rolling roller is increased. In the present embodiment, the effect of preventing buckling of the U-shaped steel sheet pile 10 can be obtained simply by forming one protrusion 15 on one flange 12, so that the roll when manufacturing by hot rolling. Increase in load can be suppressed.

(10) Since the surface on the front side of the flange 12 on which the ridge portion 15 is provided is the surface opposite to the neutral axis P of the wall structure 1, the ridge portion 15 is located farther from the neutral axis P. Therefore, a large value of the cross-sectional secondary moment I with respect to the neutral axis P can be obtained, and the cross-sectional rigidity of the flange 12 can be effectively increased.

[Second Embodiment]
Next, a steel sheet pile (hat-shaped steel sheet pile) according to a second embodiment of the present invention will be described with reference to FIG. 5A.
FIG. 5A is a cross-sectional view showing a hat-shaped steel sheet pile 20 according to the present embodiment.
The difference between the U-shaped steel sheet pile 10 and the hat-shaped steel sheet pile 20 of the first embodiment is that, in the hat-shaped steel sheet pile 20, a second flange 24 is further extended at the tip edges of the pair of webs 23, and the sheet pile main body The part 21 has a hat-shaped cross-sectional shape. Thereby, when a wall structure is constructed using a plurality of hat-shaped steel sheet piles 20, the neutral axis P of the hat-shaped steel sheet pile 20 alone and the neutral axis P of the wall structure coincide. Hereinafter, the differences will be described in detail.

  As shown to FIG. 5A, the sheet pile main-body part 21 is following the 1st flange 22, the side edge of both of this 1st flange 22, and a pair of mountain-shaped webs 23 which the front-end | tip notched, The pair of webs 23 have a pair of second flanges 24 that extend parallel to the first flange 22 and outward from the leading edge of the pair of webs 23, and a protrusion 26 is formed at a substantially central position in the width direction of the first flange 22. ing. That is, the first flange 22 corresponds to the wide flat plate of the present invention. The thickness dimension t and the width dimension b of the first flange 22 are set so that the width-thickness ratio (b / t) of the width dimension b to the thickness dimension t is in the range of 48 to 96. Yes. A joint portion 25 is provided on the distal end side of the pair of second flanges 24.

  The protruding portion 26 is provided on a surface on either side of the first flange 22 on the opposite side to the neutral axis P of the wall structure. Moreover, the cross-sectional shape orthogonal to the elongate direction of the protrusion part 26 is a substantially rectangular shape, and is the range which satisfy | fills all of Formula (3) and Formula (4) similarly to the protrusion part 15 of 1st Embodiment. Is set to

According to this embodiment, in addition to the same effects as those described above, the following effects can be achieved.
(11) Since the surface of the first flange 22 where the ridges 26 are provided is the surface opposite to the neutral axis P of the wall structure, the ridges 26 are located farther from the neutral axis P. Therefore, a large value of the cross-sectional secondary moment I with respect to the neutral axis P can be obtained, and the cross-sectional rigidity of the first flange 22 can be effectively increased.

[Third Embodiment]
Next, a steel sheet pile (hat-shaped steel sheet pile) according to a third embodiment of the present invention will be described with reference to FIG. 5B.
FIG. 5B is a cross-sectional view showing a hat-shaped steel sheet pile 20A according to the present embodiment.
The difference between the hat-shaped steel sheet pile 20 and the hat-shaped steel sheet pile 20 </ b> A of the second embodiment is that, in the hat-shaped steel sheet pile 20 </ b> A, the ridge portion 27 is formed at a substantially central position in the width direction of the pair of webs 23. Is a point. That is, the pair of webs 23 corresponds to the wide flat plate of the present invention. The thickness dimension t and the width dimension b of the pair of webs 23 are set so that the width-thickness ratio (b / t) of the width dimension b to the thickness dimension t is in the range of 48 to 96. Yes.
In addition, the cross-sectional shape orthogonal to the elongate direction of the protrusion part 27 is a substantially rectangular shape, and is in the range which satisfy | fills all of Formula (3) and Formula (4) similarly to the protrusion part 15 of 1st Embodiment. Is set to Further, the ridge portion 27 is located on the neutral axis P of the wall structure. Specifically, the protruding portion 27 is arranged with respect to the neutral shaft so that the neutral shaft P bisects the area of the substantially rectangular shape. In the present embodiment, the ridges 27 are formed to protrude inwardly on the inner surface of each web 23 (the inner surface of the hat-shaped recess), but the ridges 27 are formed on the outer side of each web 23. It may be formed to protrude outward on the surface (the surface opposite to the inner surface of the hat-shaped recess).

According to this embodiment, in addition to the same effects as those described above, the following effects can be achieved.
(12) Since the protrusions 27 are located on the neutral axis P of the wall structure, even if the protrusions 27 are provided on the pair of webs 23, the neutral axis P is not displaced, and no major design change is involved. . Therefore, a wall structure can be constructed as in the case of using a conventional hat-shaped steel sheet pile.

[Fourth Embodiment]
Next, a steel sheet pile (Z-shaped steel sheet pile) according to a fourth embodiment of the present invention will be described with reference to FIG. 6A.
FIG. 6A is a cross-sectional view showing a Z-shaped steel sheet pile 30 according to the present embodiment.
The difference between the hat-shaped steel sheet pile 20A and the Z-shaped steel sheet pile 30 of the third embodiment is that the Z-shaped steel sheet pile 30 of the present embodiment has a cross-sectional shape in which the sheet pile main body portion 21 of the hat-shaped steel sheet pile 20A is substantially halved. It is a point provided with the sheet pile main-body part 31 which has. Hereinafter, the differences will be described in detail.

As shown in FIG. 6A, the sheet pile main body 31 includes a web 32, a first flange 33 and a second flange 34 that extend in parallel to each other from both side edges of the web 32 and in opposite directions across the web 32. have. A protrusion 36 is formed at a substantially central position in the width direction of the web 32.
That is, the pair of webs 32 corresponds to the wide flat plate of the present invention. The thickness dimension t and the width dimension b of the pair of webs 32 are set so that the width-thickness ratio (b / t) of the width dimension b to the thickness dimension t is in the range of 48 or more and 96 or less. Yes.
In addition, the cross-sectional shape orthogonal to the elongate direction of the protrusion part 36 is a substantially rectangular shape, and is the range which satisfy | fills all of Formula (3) and Formula (4) similarly to the protrusion part 27 of 3rd Embodiment. Is set to Moreover, the protrusion part 36 is located on the neutral axis | shaft P of the wall structure at the time of comprising a wall structure combining the said Z-shaped steel sheet pile 30 in multiple numbers. Specifically, like the hat-shaped steel sheet pile 20A of the third embodiment, the protruding portion 36 is arranged with respect to the neutral shaft so that the neutral shaft P bisects the substantially rectangular area. .

According to this embodiment, in addition to the same effects as those described above, the following effects can be achieved.
(13) Since the ridge portion 36 is positioned on the neutral axis P of the wall structure, even if the ridge portion 36 is provided on the web 32, the neutral axis P is not displaced, and no major design change is involved. Therefore, a wall structure can be constructed similarly to the case where a conventional Z-shaped steel sheet pile is used.

[Fifth Embodiment]
Next, a steel sheet pile (linear steel sheet pile) according to a fifth embodiment of the present invention will be described with reference to FIG. 6B.
FIG. 6B is a cross-sectional view showing the linear steel sheet pile 40 according to the present embodiment.
The straight steel sheet pile 40 includes a sheet pile main body portion 41 formed by one long flange (flat plate) 42 and a joint portion 43 formed at both side edges of the flange 42. And the protrusion 44 is formed in the approximate center position in the width direction of the flange 42.
That is, the flange 42 corresponds to the wide flat plate of the present invention. The flange 42 has the thickness dimension t and the width dimension b set so that the width-thickness ratio (b / t) of the width dimension b to the thickness dimension t is in the range of 48 to 96.
The cross-sectional shape orthogonal to the longitudinal direction of the ridge 44 is substantially rectangular, and is set within a range that satisfies all of the expressions (3) and (4), like the ridge 15.
According to this embodiment, the same effects as described above can be obtained.

[Modifications According to the Present Invention]
In addition, this invention is not limited to the said embodiment, Including other structures etc. which can achieve the objective of this invention, the deformation | transformation etc. which are shown below are also contained in this invention.
For example, in the said embodiment, although the U-shaped steel sheet pile, the hat-shaped steel sheet pile, the Z-shaped steel sheet pile, and the linear steel sheet pile were demonstrated as a steel sheet pile, the steel sheet pile of this invention has at least 1 elongate flat plate. The sheet pile main body part formed including one or more sheets and a steel sheet pile provided with joint parts formed on both side edges of the sheet pile main body part may be used, and the form is not particularly limited.

Moreover, although the said embodiment demonstrated the case where a flange was a wide flat plate of this invention among the sheet pile main-body parts in 1st Embodiment, as a steel sheet pile of this invention, at least one part among sheet pile main-body parts. It is only necessary that the protrusions are provided on (for example, at least one of the flange or the pair of webs). Further, the ridges may be provided on all of the flange or the pair of webs.
Similarly, although the case where the web of the Z-shaped steel sheet pile is the wide flat plate of the present invention has been described in the fourth embodiment, the first flange and the second flange may be provided with protrusions.
Similarly, in another embodiment in which the sheet pile main body portion is configured by combining a plurality of flat plates, it is only necessary that the protrusions are provided on at least a part (at least one flat plate) of the sheet pile main body portions.

Moreover, the cross-sectional shape orthogonal to the longitudinal direction of the protrusion is not limited to a substantially rectangular shape, and may be, for example, a substantially semicircular shape, a substantially semielliptical shape, or a polygon such as a triangle. Here, the cross-sectional view of the U-shaped steel sheet pile 10B which concerns on the modification of this invention in FIG. 7 is shown. This U-shaped steel sheet pile 10B has a protrusion 16 having a substantially semicircular cross section. About the formation location and cross-sectional area of the ridge part 16, and a cross-sectional secondary moment, it is the same as the U-shaped steel sheet pile 10 of 1st Embodiment.
Further, the protrusions are not limited to those integrally formed on the flange or the like by hot rolling, but may be those retrofitted by welding on the flange or the like.

  According to the steel sheet pile of the present invention, the provision of a protrusion having a predetermined shape along the longitudinal direction on a wide flat plate has sufficient rigidity against buckling and has workability. Can be improved.

DESCRIPTION OF SYMBOLS 1 ... Wall structure 10, 10A, 10B ... U-shaped steel sheet pile 11, 21, 31, 41 ... Sheet pile main-body part 12, 42 ... Flange (wide flat plate)
13 ... Web (flat plate)
14, 25, 35, 43 ... joint parts 15, 15A, 15B, 16, 26, 27, 36, 44 ... ridge parts 20, 20A ... hat-shaped steel sheet pile 22 ... first flange (wide flat plate)
23, 32 ... Web (wide plate)
24 ... Second flange (flat plate)
30 ... Z-shaped steel sheet pile 33 ... 1st flange (flat plate)
34 ... Second flange (flat plate)
40 ... Linear steel sheet pile b ... Flat plate width dimension h ... Cross sectional protrusion dimension t ... Flat plate thickness dimension w ... Projection width dimension

Claims (2)

Sheet pile body,
A joint portion formed on both side edges of the sheet pile main body portion,
At least a part of the sheet pile main body is a wide flat plate formed such that the width-thickness ratio (b / t) of the width dimension (b) to the thickness dimension (t) is 48 or more and 96 or less,
The sheet pile main body is parallel to the first flange, a pair of or one web continuous to both or one side edge of the first flange, and the pair of or one web leading edge. And having a pair or one second flange extending outward,
The web is the wide plate;
On one surface of the wide flat plate of the sheet pile main body portion, a single ridge extending along the longitudinal direction is provided at the center of the wide flat plate, and the distance between the side edge of the wide flat plate and the ridge. The ratio of thickness (t) to is 48 or less,
The neutral axis of the wall structure when the sheet pile main body constitutes a wall structure bisects the area of the ridge,
The projecting portion has a cross-sectional shape orthogonal to the longitudinal direction, which is any of a substantially rectangular shape, a substantially semicircular shape, a substantially semi-elliptical shape, or a substantially triangular shape, and is further orthogonal to the longitudinal direction. The cross-sectional area (A) of the ridge portion in the cross-sectional shape and the cross-sectional secondary moment (I) of the ridge portion based on the one surface are determined by the following equations (1) and (2). Steel sheet pile provided to be within the specified range.
A ≧ b · t / 20 (1)
^{I ≧ b · t 3/11} · γ ··· (2)
Here, γ = 1/2 · (8 (1 + 2δ) −1) ² −1
δ = A / bt In the steel sheet pile according to claim 1,
The protruding portion is a steel sheet pile integrally formed on the wide flat plate.

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