JP2005023546A - Metal pipe strut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal pipe strut controlling the increase in bending stress without using an outside mounting type reinforcing member in the metal pipe strut having an opening section in a side wall applying stress at least 5,000N m of bending moment to the strut base section. <P>SOLUTION: The metal pipe strut is so constituted that the increase in bending stress caused by the existence of a strut opening section 2 formed in the side wall of a metal pipe 1 can be controlled by either means that (1) at least a wall thickness of the real thickness of a section of the opening section is thickened, (2) at least the real thickness of the section of the opening makes a multiple wall and (3) at least an outside diameter of the real thickness of the section of the opening section is enlarged. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal pipe column having excellent bending stress resistance used for a road lighting pole, a traffic signal pole, an electric road sign pole, and the like.
[0002]
[Prior art]
Since the metal pipe column used for the above-described pole or the like is subjected to a bending stress by a cross wind, if the allowable bending stress of the metal material used for the metal tube column is exceeded, the metal tube column collapses.
[0003]
In particular, since it is necessary to attach an electrical device such as a ballast or joint box near the base of the column, an opening is formed in the side wall near the base of the column in order to store them inside the column. A lid is placed on top. In this opening, the actual metal part is notched from the metal tube column by that amount, and the degree of bending stress increases due to the presence of the column opening.
[0004]
Here, the allowable bending stress degree is uniquely determined by the type of metal material used for the metal tube column as seen in the Japan Lighting Equipment Manufacturers Association Standard “Lighting Pole Strength Calculation Standard” (JIL 1003: 2003). It has been established.
[0005]
The bending stress σ is obtained by dividing the bending moment M received by the metal pipe column by the section modulus Z, and has a relationship of σ = M / Z. This bending moment M is generated in the metal tube column by receiving a wind load from the side, and depends on the projected area of the metal tube column, that is, the area when the metal tube column is viewed from the front or side. The wind speed when calculating the allowable bending stress is set to 60 m / sec. Further, the section modulus Z depends on the cross-sectional area of the metal pipe column.
[0006]
Therefore, the shape, height, outer diameter, and thickness of the metal tube strut are designed to be less than the allowable bending stress level determined for each metal material of the metal tube strut.
[0007]
However, if there is an opening in the metal tube strut, the metal flesh is notched from the metal tube strut, and accordingly, the section modulus of the opening is reduced, and the bending stress σ at the lower end of the opening is reduced. Therefore, a metal material having a higher allowable bending stress σ must be used as it is.
[0008]
In order to suppress an increase in bending stress due to the presence of the opening, an external-type reinforcing member that covers the opening is installed to reinforce the opening, and then a lid is installed.
[0009]
Non-Patent Document 1 describes an external reinforcing member that fillet welds a U-shaped frame body to the outer surface of a rectangular opening to prevent deformation of the support opening.
[0010]
FIG. 4A is a front view of a conventional example showing reinforcement of the opening by an external reinforcing member. 4 (b) is a cross-sectional view of the opening 2 in FIG. 4 (a) on the AA plane, and FIG. 4 (c) is a portion away from the upper end of the opening in FIG. 4 (a). It is sectional drawing of a certain BB surface.
[0011]
A portion of the metal tube 1 having an outer diameter D ₀ and a wall thickness t ₀ is cut out in a strip shape by a length L at a central angle θ to form an opening 2. Therefore, as shown in FIG. 4 (b), the cross section of the opening has a real part having a central angle of 360 ° −θ. A frame 5 having a U-shaped cross section is welded to a fillet portion 11 on the outer surface of the outer periphery of the opening. This frame body has bolt holes 12, and electrical devices such as ballasts and joint boxes are housed in the pillars through the openings, and then a lid (not shown) is attached and fixed by bolts 9. . ,
As shown in FIG. 4C, the reinforcing frame is not installed in a portion away from the upper end of the opening. In the case where the metal tube 1 is a straight pipe column formed with the same outer diameter and thickness from the column base to the column tip even at a portion away from the upper end of the opening, the outer diameter D ₀ and the wall thickness t ₀ .
[0012]
[Non-Patent Document 1] “Road / Tunnel Lighting Equipment Specifications” p. 2-10, issued in April 2001, Construction Electrical Engineering Association of Japan [0013]
[Problems to be solved by the invention]
The external reinforcing member at the opening of the metal pipe column of the above-described conventional example has a possibility that it may become an obstacle for a pedestrian who passes near the column because the frame body and the lid protrude from the outer surface of the column.
[0014]
Further, since the external reinforcing member needs to be welded to the outer periphery of the metal tube support column, there is a problem that it takes time and labor for the work.
[0015]
The present invention solves the above-described conventional problems, and without using an external reinforcing member, an increase in the bending stress due to the presence of an opening formed in the side wall near the base of the metal tube column is increased. The object is to provide a suppressed metal tube strut.
[0016]
[Means for Solving the Problems]
When the inventor receives a stress of a bending moment of 5000 N · m or more at the base of the column, the bending stress increases due to the presence of the column opening, but the external reinforcing member has the above-mentioned drawbacks. Therefore, a reinforcing means to replace the external reinforcing member was examined. As a result, the idea that the increase in the bending stress can be suppressed without reinforcing an external reinforcing member by reinforcing the actual wall portion of the opening cross section of the metal tube column. The present invention has been completed based on this idea.
[0017]
The metal tube strut of the present invention is a metal tube strut having an opening in the side wall that receives a stress of a bending moment of 5000 N · m or more on the base of the strut. The increase in the bending stress due to the presence of the strut opening is the following ( It is suppressed by any means of 1) to (3).
(1) At least the wall thickness of the real part of the cross section of the opening is made thicker than the wall thickness of the real part of the cross section other than the opening.
(2) At least the wall of the real part of the opening section is multiplexed.
(3) At least the outer diameter of the real part of the cross section of the opening is made larger than the outer diameter of the real part of the cross section other than the opening.
[0018]
In this way, the metal tube strut to which the means (1) to (3) are applied, the electrical equipment such as the ballast and the joint box is housed in the strut through the opening, and then the top of the opening. A lid is installed. Since the lid can be fixed with bolts and nuts or the like, the lid can be easily removed during maintenance of electrical equipment or the like.
[0019]
Here, “the real part of the cross section of the opening” means “the remaining portion when the opening is formed by cutting a part of the metal tube strut into a strip shape of length L × center angle θ”. Of length L × center angle 360 ° −θ ”. In the present invention, it is sufficient to apply the means (1) to (3) only to the actual part of the cross section of the column opening, but the metal other than the opening, that is, the metal below the lower end of the opening. It does not exclude application to pipe struts. In addition, application of the portion above the upper end of the opening to the metal tube column is not excluded, but even if the means (1) to (3) are applied to a portion substantially above the upper end of the opening. The reinforcement effect is saturated and the cost is increased.
[0020]
The metal pipe column according to the present invention may be a straight tube column formed with the same outer diameter and thickness from the column base to the column tip, or a step with a step formed in the middle to reduce the column tip side. It may be a pillar. Alternatively, it may be a tapered column or a tapered column with a step, in which a taper is provided in the direction from the column base to the column tip, or a step is further provided, and the outer diameter or thickness is gradually reduced.
[0021]
Next, road lamps, traffic signals, road signs, and the like are attached to the pole tip portion of the metal tube strut according to the present invention, but the shape of the pole tip portion of the attachment portion is not particularly limited. That is, it may have any shape such as a linear shape, an arc shape, a folded linear shape, a Y shape, an inverted L shape, and an arch shape.
[0022]
Moreover, there is no restriction | limiting in particular as a metal pipe used for the metal pipe support | pillar which concerns on this invention, However, A steel pipe, a stainless steel pipe, an aluminum pipe, etc. are preferable. The shape of the opening formed in the metal tube strut according to the present invention is not particularly limited, but an oval shape or a rectangular shape with rounded corners is preferable.
[0023]
In addition, there is no restriction | limiting in particular in the cross-sectional shape of the metal tube used for a metal tube support | pillar, A metal tube of various shapes, such as circular, a square, a hexagon, and an octagon, can be used. A circular metal tube is preferable from the viewpoint of workability.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiments of the present invention are shown below.
[0025]
FIG. 1A shows the above-mentioned means (1) of the present invention, that is, a column when at least the wall thickness of the real part of the cross section of the opening is made thicker than the wall thickness of the real part of the cross section other than the opening. It is a front view of an opening part. 1 (b) is a cross-sectional view of the opening 2 in FIG. 1 (a) on the AA plane, and FIG. 1 (c) is a portion away from the upper end of the opening in FIG. 1 (a). It is sectional drawing of the BB surface in a.
[0026]
A part of the metal tube 1 is cut out in a strip shape by a length L at a central angle θ to form an opening 2, but no external reinforcing member is provided. Instead of providing an externally attached reinforcing member, the wall of the opening portion here has the same outer diameter as D ₀ , but the wall thickness is t _1, which is larger than the thickness t ₀ of the portion other than the opening portion. It is thick. Thus, as seen in FIG. 1 (b), the opening cross-section is a central angle 360 ° - [theta], the real wall portion of the thickness t ₁ is present.
[0027]
Then, in the distant portion on the opening upper end, in the case of applying the one seen in FIG. 1 (c) to the straight pipe posts, the metal tube 1 remains outside diameter D ₀ and a wall thickness t _0.
[0028]
As a method for increasing the wall thickness of the metal tube only at the opening portion, a spinning method is typical, but other processing methods may be used. The direction of increasing the wall thickness may be increased toward the inner side of the tube as shown in FIG. 1 (b), or may be increased toward the outer side of the tube as opposed to FIG. 1 (b). . It may be thicker in both the inner and outer directions of the tube.
[0029]
Further, the wall thickness may be increased only in the opening portion, and a step may be provided so that the portion other than the opening portion is thin, or a taper may be provided so as to be gradually reduced. In addition, the wall thickness of the part other than the opening is extended to the metal tube strut above the upper end of the opening or below the lower end from the viewpoint of ensuring the strength and rigidity, and is formed as a thick wall. However, even if it is thicker than the upper end of the opening, the reinforcing effect is saturated and only the cost is increased. However, for the portion below the lower end of the opening, that is, the base portion of the metal tube column, the same thickness as the wall thickness of the opening may be extended as it is to the vicinity of the ground for the convenience of thick-wall processing.
[0030]
This metal tube support pole is a road lighting pole after electrical equipment such as ballasts and joint boxes are stored inside the support post through the opening, and then a lid (not shown) is attached to the opening with a bolt or the like. Used for etc.
[0031]
FIG. 2A is a front view of the above-mentioned means (2) of the present invention, that is, a column opening when at least the wall of the actual part of the opening cross section is multiplexed. 2 (b) is a cross-sectional view of the opening 2 in FIG. 2 (a) along the AA plane, and FIG. 2 (c) is a portion away from the upper end of the opening in FIG. 2 (a). It is sectional drawing of the BB surface in a.
[0032]
Here, instead of providing an external reinforcing member, the wall of the opening portion is doubled. The outer wall remains the metal tube 1 having the outer diameter D ₀ and the thickness t ₀ , and a part of the metal tube 1 is cut out into a strip shape with a central angle θ by a length L to form the opening 2. It has been done. A cut-out tubular reinforcing member having an outer diameter substantially equal to the inner diameter of the steel pipe strut and having a length L and a center angle of 360 ° -θ is provided on the inner surface of the steel pipe strut, except for the strip-shaped notch. 3 is provided. Real meat of the opening cross-section, have a thickness of t ₂ along the thickness of the inner and outer walls is thicker than the thickness t ₀ of the portion other than the opening portion. Thus, as seen in FIG. 2 (b), the opening cross-section is a central angle 360 ° - [theta], the real wall portion of the thickness t ₂ is present.
[0033]
Then, in the distant portion on the opening upper end, in the case of applying the one seen in FIG. 2 (c) in a straight pipe posts, the metal tube 1 remains outside diameter D ₀ and a wall thickness t _0.
[0034]
In FIG. 2 (b), a cut-out tubular reinforcing member is installed on the inner surface of the steel pipe strut. The outer surface of the steel pipe strut has an inner diameter substantially equal to the outer diameter of the steel pipe strut, and has a length L and a center. A cut-out tubular reinforcing member having an angle of 360 ° −θ may be provided.
[0035]
In addition, it is not always necessary to provide the cutout tubular reinforcing member in the portion other than the opening, but from the viewpoint of strength, rigidity and workability, the portion above the upper end of the opening having the length L or below the lower end is provided. It is preferable that a notched tubular reinforcing member is provided extending to the metal tube support. In the case of extending to the metal tube strut in a portion above the upper end or below the lower end of the opening, the upper and lower end portions of the reinforcing member can be a solid tube with no notch. However, even if the multiple walls are provided up to a portion substantially above the upper end of the opening, the reinforcing effect is saturated and only the cost is increased. In addition, although the double wall is used here, it is not restricted to a double wall, A wall more than triple may be sufficient.
[0036]
As a method of joining the above-mentioned tube-shaped reinforcing member to the inner surface or the outer surface of the opening portion of the metal tube strut, fixing means such as a bolt and nut may be used in addition to welding. In addition, when extending to the vicinity of the top and bottom of the opening portion having the length L, the reinforcing member is a solid tubular reinforcing member having a notch with the central angle θ at the upper end and the lower end of the reinforcing member. Therefore, it can join by shrink fitting or screwing.
[0037]
This metal tube support pole is a road lighting pole after electrical equipment such as ballasts and joint boxes are stored inside the support post through the opening, and then a lid (not shown) is attached to the opening with a bolt or the like. Used for etc.
[0038]
FIG. 3 (a) shows the above-mentioned means (3) of the present invention, that is, the column opening when the outer diameter of at least the actual part of the opening section is larger than the outer diameter of the actual part of the section other than the opening section. It is a front view of a part. 3 (b) is a cross-sectional view of the opening 2 in FIG. 3 (a) on the AA plane, and FIG. 3 (c) is a part away from the upper end of the opening in FIG. 1 (a). It is sectional drawing of the BB surface in a.
[0039]
A part of the metal tube 1 is cut out in a strip shape by a length L at a central angle θ to form an opening 2, but an external reinforcing member is not provided. Instead of providing an externally attached reinforcing member, the wall thickness of the opening portion here is the same as t ₀ , but the outer diameter is D ₃ and the outer diameter D ₀ of the portion other than the opening portion. Is also getting bigger. Therefore, as shown in FIG. 3B, the cross section of the opening has a real part having a central angle of 360 ° −θ and a thickness t ₀ and a maximum outer diameter D ₃ .
[0040]
Then, in the distant portion on the opening upper end, in the case of applying the one seen in FIG. 3 (c) in a straight pipe posts, the metal tube 1 remains outside diameter D ₀ and a wall thickness t _0.
[0041]
As a method of expanding the outer diameter of the metal tube only by the opening portion, a spinning method is typical, but other processing methods may be used. The wall thickness other than the opening portion may be the same as shown in FIG. If the diameter is sufficiently expanded, the wall thickness can be reduced.
[0042]
Further, the diameter may be increased so that only the opening portion is enlarged and the portion other than the opening portion is not enlarged, or a taper may be provided so that the diameter is gradually reduced. In addition, from the viewpoint of ensuring strength and rigidity, the diameter of the portion other than the opening is extended to the metal tube column in the portion above the upper end or below the lower end, and is formed with the expanded diameter. However, even if the diameter is expanded to a position considerably higher than the upper end of the opening, the reinforcing effect is saturated and only the cost is increased. However, for the portion below the lower end of the opening, that is, the base portion of the metal tube support, the same diameter as the diameter of the opening may be extended as it is to the vicinity of the ground for the convenience of the diameter expansion process.
[0043]
This metal tube support pole is a road lighting pole after electrical equipment such as ballasts and joint boxes are stored inside the support post through the opening, and then a lid (not shown) is attached to the opening with a bolt or the like. Used for etc.
[0044]
【Example】
Here, taking as an example a straight pipe strut having a straight pole tip of 8 m in height, the opening portion of the metal pipe strut of the present invention is thickened, that is, the wall thickness of the actual wall portion of the cross section of the opening is thickened. Thus, the degree of suppression of the increase in the bending stress degree in the opening is given.
[0045]
In order, (1) when no reinforcement is performed, (2) when a conventional externally attached reinforcing member (FIG. 4) is provided, (3) the wall thickness of the actual wall portion of the opening section of the present invention is increased. It verified about the case (FIG. 1).
[0046]
In the case of a metal pipe column having a height of 8 m, an outer diameter of 161 mm and a wall thickness of 4.2 mm are usually used. The opening usually has a length L of 600 mm, and the center of the opening is formed at a position of 750 mm from the base of the metal tube column. As the metal pipe support, a steel pipe support of standard SS400 was used. The allowable cross-sectional stress degree of this steel pipe column is 235 N / mm ² .
[0047]
If the metal tube column does not have an opening, the section modulus Z is 79 cm ³ and the bending stress σ is 93.3 N / mm ² .
[0048]
(1) When no reinforcement is made, the section modulus Z = 27.3 cm ³
Bending stress degree σ = 270 N / mm ²
(2) When a conventional external-type reinforcing member (FIG. 4) is provided (the external-type reinforcing member of the conventional example has a frame thickness t _e = 3.2 mm, an outer width a = 150 mm, inner width b = 130 mm, depth c to metal tube column c = 55 mm)
Section modulus Z = 50.4cm ³
Bending stress σ = 146 N / mm ²
(3) When the wall thickness of the real part of the cross section of the opening of the present invention is increased (FIG. 1)
(A) Section coefficient Z = 31.4 cm ³ when the thickness of the real part of the cross section of the opening is 5.0 mm
Bending stress σ = 235 N / mm ²
(B) Section coefficient Z = 50.4 cm ³ when the thickness of the real part of the cross section of the opening is 11.2 mm
Bending stress σ = 146 N / mm ²
This result by having an opening, bending stress about σ is increased 176.7N / mm ^2, the place to be 270N / mm ^2, in the present invention, when the thickness 5.0mm of (a) bending stress about σ is suppressed to 235N / mm ^2, bending stresses σ when the thickness 11.2mm in (b) is suppressed to 146N / mm ^2.
[0049]
Therefore, since the allowable cross-sectional stress of steel pipe struts of standard SS400 is 235 N / mm ² or less in all cases, the Japan Lighting Equipment Manufacturers Association Standard “Lighting Pole Strength Calculation” can be used without using an external reinforcing member. The “reference” (JIL 1003: 2003) can be cleared, and it does not collapse.
[0050]
In addition, in the conventional external-type reinforcing member, the bending stress degree σ = 146 N / mm ² can be suppressed, but this is an overspec, and the bending stress degree is suppressed more than necessary. ,Understandable.
[0051]
Similarly, taking a steel pipe strut with a vertical tip of 10 m in height as an example, the portion of the opening of the metal tube strut of the present invention is thickened, that is, the wall thickness of the actual part of the cross section of the opening is thickened. The degree of suppression of the increase in the bending stress degree in the opening is given.
[0052]
In order, (1) when no reinforcement is performed, (2) when a conventional externally attached reinforcing member (FIG. 4) is provided, (3) the wall thickness of the actual wall portion of the opening section of the present invention is increased. It verified about the case (FIG. 1).
[0053]
In the case of a metal pipe column having a height of 10 m, an outer diameter of 171 mm and a wall thickness of 4.2 mm is usually used. The opening usually has a length L of 600 mm, and the center of the opening is formed at a position of 750 mm from the base of the metal tube column. As the metal pipe support, a steel pipe support of standard SS400 was used. The allowable cross-sectional stress degree of this steel pipe column is 235 N / mm ² .
[0054]
If the metal pipe column does not have an opening, the section modulus Z is 89.6 cm ³ and the bending stress σ is 119 N / mm ² .
[0055]
(1) Section modulus Z = 34.7 cm ³ when no reinforcement is applied
Bending stress degree σ = 308 N / mm ²
(2) When a conventional external-type reinforcing member (FIG. 4) is provided (the external-type reinforcing member of the conventional example has a frame thickness t _e = 3.2 mm, an outer width a = 150 mm, inner width b = 130 mm, depth c to metal tube column c = 55 mm)
Section modulus Z = 59.5 cm ³
Bending stress σ = 180 N / mm ²
(3) When the wall thickness of the real part of the cross section of the opening of the present invention is increased (FIG. 1)
(A) Section modulus Z = 45.8 cm ³ when the thickness of the real part of the cross section of the opening is 5.9 mm
Bending stress σ = 234 N / mm ²
(B) Section modulus Z = 59.7 cm ³ when the thickness of the real part of the cross section of the opening is 8.5 mm.
Bending stress σ = 179 N / mm ²
This result by having an opening, increased bending stress about σ is 189N / mm ^2, the place to be 308N / mm ^2, in the present invention, the bending when the 5.9mm thickness (a) stress degree σ is suppressed to 234N / mm ^2, bending stresses σ when the thickness 8.5mm of (b) is suppressed to 179N / mm ^2.
[0056]
Therefore, since the allowable cross-sectional stress of steel pipe struts of standard SS400 is 235 N / mm ² or less in all cases, the Japan Lighting Equipment Manufacturers Association Standard “Lighting Pole Strength Calculation” can be used without using an external reinforcing member. The “reference” (JIL 1003: 2003) can be cleared, and it does not collapse.
[0057]
In addition, in the conventional external-type reinforcing member, the bending stress degree σ = 180 N / mm ² can be suppressed, but this is an overspec, and the bending stress degree is suppressed more than necessary. I can understand.
[0058]
【The invention's effect】
According to the metal pipe support of the present invention, an increase in the bending stress due to the presence of the support opening formed on the side wall of the base can be suppressed without using the opening reinforcing member. Therefore, there is no need to provide a reinforcing member that protrudes from the outer surface, so there is no obstacle to the pedestrian, and there is no need to weld to attach the reinforcing member, so that workability is improved accordingly.
[0059]
[Brief description of the drawings]
FIG. 1 (a) is a front view of a column opening when the wall thickness of a real part of the opening section is increased, and FIG. 1 (b) is an opening of FIG. 1 (a). It is sectional drawing in the AA surface of 2. FIG. FIG.1 (c) is sectional drawing of the BB surface in the part away from the upper end of the opening part of Fig.1 (a) upwards.
FIG. 2 (a) is a front view of a column opening when a real part of the opening section is a double tube, and FIG. 2 (b) is an opening of FIG. 2 (a). It is sectional drawing in the AA surface of 2. FIG. FIG.2 (c) is sectional drawing of the BB surface in the part away from the upper end of the opening part of Fig.2 (a).
FIG. 3A is a front view of a support opening when an outer diameter of a real part of the opening cross section is increased, and FIG. 3B is an opening of FIG. 3A. It is sectional drawing in the AA surface of 2. FIG. FIG.3 (c) is sectional drawing of the BB surface in the part away from the upper end of the opening part of Fig.3 (a) upwards.
FIG. 4 (a) is a front view of a conventional example showing an external reinforcement member of an opening of a metal tube strut, and FIG. 4 (b) is an opening 2 of FIG. 4 (a). It is sectional drawing in the AA surface. FIG.4 (c) is sectional drawing of the BB surface in the part away from the upper end of the opening part of Fig.4 (a).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal pipe 2 Opening part 3 Notch tubular reinforcement member 5 Frame body 9 Bolt 11 Fillet part 12 Bolt hole

Claims (4)

A metal tube strut having an opening in a side wall that receives a stress of bending moment of 5000 N · m or more on the base of the strut, and at least the wall thickness of the real part of the cross section of the opening is the wall of the real part of the cross section other than the opening An increase in the bending stress due to the presence of the column opening is suppressed by making it thicker than the thickness. A metal tube column having an opening on the side wall that receives a stress of 5000 N · m or more on the column base, and bending due to the presence of the column opening by multiplying at least the wall of the real part of the opening section A metal tube strut characterized in that an increase in stress is suppressed. A metal tube column having an opening in the side wall that receives a stress of bending moment of 5000 N · m or more on the column base, and at least the outer diameter of the real part of the cross section of the opening is outside the real part of the cross section other than the opening. An increase in the bending stress due to the presence of the column opening is suppressed by making it larger than the diameter, and the metal tube column is characterized in that The metal pipe column according to any one of claims 1 to 3, wherein a lid is attached to the column opening.

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