JP7460431B2 - Utility poles and methods of manufacturing utility poles - Google Patents

Description

The present disclosure relates to a utility pole and a method of manufacturing the utility pole.

Utility poles are generally constructed from concrete poles or steel pipes (see Patent Document 1).

Japanese Patent Application Publication No. 2014-20096

Steel poles can be stronger than concrete poles. However, since steel pipe utility poles are evaluated for their yield strength at the outermost edge, it is necessary to increase the tube diameter and thickness in order to increase the yield strength. Therefore, the material cost and construction cost of the utility pole will increase.

One aspect of the present disclosure aims to provide a utility pole in which the diameter and thickness of the steel pipe can be reduced.

One aspect of the present disclosure is a utility pole having a first steel pipe with a hollow portion filled with concrete along at least a portion of the axial direction.

With this configuration, the concrete filled in the hollow portion increases the restraining force of the first steel pipe. Therefore, the diameter and thickness of the first steel pipe can be reduced while maintaining the strength of the utility pole with inexpensive concrete. As a result, the cost of the utility pole is reduced.

In one aspect of the present disclosure, the first steel pipe may be filled with concrete at least near the first end in the axial direction. According to such a configuration, by making the first end portion the lower end portion of the utility pole, the proof strength of the lower end portion on which a relatively large load or moment acts on the first steel pipe can be increased. Therefore, reduction in the pipe diameter and thickness of the first steel pipe can be promoted.

In one aspect of the present disclosure, the first steel pipe may have a hollow portion that is not filled with concrete. With this configuration, concrete is selectively filled in the portion that requires high strength. This makes it possible to suppress increases in material costs and weight of the utility pole.

One aspect of the present disclosure provides a second steel pipe that is arranged parallel to the first steel pipe and has a hollow portion filled with concrete in at least a portion of the axial direction, and a second steel pipe that connects the first steel pipe and the second steel pipe to the first steel pipe. It may further include a beam connecting in the radial direction. The first steel pipe and the second steel pipe may each be filled with concrete at least at a portion connected to the beam. According to such a configuration, in each of the first steel pipe and the second steel pipe, the proof strength of the connection portion with the beam on which a relatively large load or moment acts can be increased. Therefore, it is possible to promote reduction in the pipe diameter and thickness of each of the first steel pipe and the second steel pipe.

In one aspect of the present disclosure, a portion of the first steel pipe where the bending moment acting on the first steel pipe becomes zero when a load in the axial direction of the beam is applied to a connection portion of the first steel pipe with the beam; The part of the second steel pipe where the bending moment acting on the second steel pipe becomes zero when a load in the axial direction of the beam is applied to the connection part of the second steel pipe with the beam is not filled with concrete. A section may be provided. According to such a configuration, since it is possible to reduce the amount of concrete filled in the portion where the required bending strength is relatively low, it is possible to reduce the material cost and weight of the utility pole while suppressing a decrease in the strength of the utility pole.

Another aspect of the present disclosure is a method for manufacturing a utility pole that includes a step of filling a hollow portion of a steel pipe with concrete in at least a portion of the axial direction.

According to such a configuration, the binding force of the steel pipe is improved by the concrete filled in the hollow portion. Therefore, the diameter and thickness of the steel pipe can be reduced while maintaining the strength of the utility pole using inexpensive concrete. As a result, the cost of utility poles is reduced.

In one aspect of the present disclosure, in the filling process, a non-filled portion in which concrete is not filled may be formed in the steel pipe. With this configuration, by selectively filling concrete in portions that require high strength, it is possible to suppress increases in material costs and weight of the utility pole.

In one aspect of the present disclosure, the filling step may involve placing a mesh at the boundary of the non-filled portion and then pouring the unhardened concrete into the hollow portion. With this configuration, the non-filled portion can be formed at low cost.

FIG. 1A is a schematic front view of a utility pole in an embodiment, and FIG. 1B is a schematic cross-sectional view taken along line IB-IB in FIG. 1A. FIG. 2 is a schematic diagram showing the distribution of bending moments in the utility pole of FIG. FIG. 3 is a schematic cross-sectional view of a first end of a first steel pipe in the utility pole of FIG. FIG. 4 is a schematic front view of a beam in the utility pole of FIG. FIG. 5 is a flowchart showing a method for manufacturing a utility pole in the embodiment. 6A is a schematic front view of a beam in an embodiment different from FIG. 5, and FIG. 6B is a schematic front view of a beam in an embodiment different from FIGS. 5 and 6A.

Embodiments to which the present disclosure is applied will be described below with reference to the drawings.
[1. First embodiment]
[1-1. composition]
A utility pole 1 shown in FIG. 1A is a gate-shaped utility pole used to supply electricity to railway vehicles. The utility pole 1 is installed along the railway line.

The utility pole 1 includes a first steel pipe 2, a second steel pipe 3, a beam 4, a first arm 5, a second arm 6, a first bracket 7, and a second bracket 8. The utility pole 1 is installed on the ground by being connected to a first steel pipe pile 11 and a second steel pipe pile 12 that are placed underground.

<First steel pipe>
The first steel pipe 2 is arranged so that the central axis is parallel to the vertical direction (that is, so as to extend in the vertical direction) when the utility pole 1 is installed.

The first steel pipe 2 is a known structural steel pipe having a hollow portion. The first steel pipe 2 has a first end 21 in the axial direction that is close to the ground when the utility pole 1 is installed (i.e., that constitutes the lower end), and a second end 22 in the axial direction that is opposite the first end 21 (i.e., that constitutes the upper end).

As shown in FIG. 1B, the first steel pipe 2 has a hollow portion filled with concrete 10 in at least a portion of the axial direction. In this embodiment, the first steel pipe 2 has a first filled portion 23, a second filled portion 24, a first unfilled portion 25, and a second unfilled portion 26.

The first filled section 23 is a portion near the first end 21 where the concrete 10 is filled. The first filled section 23 is provided in the first steel pipe 2 from the lower end of the first end 21 to a position above the retaining wall 13 when the utility pole 1 is installed.

The second filled section 24 is a portion where concrete 10 is filled at the connection with the beam 4 described below. The second filled section 24 is provided in the first steel pipe 2 from the upper end of the beam 4 to a position where it overlaps horizontally with the first bracket 7 when the utility pole 1 is installed.

The first non-filled section 25 and the second non-filled section 26 are portions where the hollow section is not filled with concrete 10. The first non-filled section 25 is provided between the first filled section 23 and the second filled section 24 in the axial direction of the first steel pipe 2. The second non-filled section 26 is provided between the second filled section 24 and the upper end of the second end section 22 of the first steel pipe 2.

As shown in FIG. 2, the first non-filled portion 25 includes a portion of the first steel pipe 2 where the bending moment M1 acting on the first steel pipe 2 becomes zero when a load F in the axial direction of the beam 4 is applied to the connection portion of the first steel pipe 2 with the beam 4. The shaded portion in FIG. 2 indicates the distribution of the magnitude of the bending moment M1 in the axial direction of the first steel pipe 2.

As shown in FIG. 3, when the utility pole 1 is installed, the lower end of the first steel pipe 2 is connected to the upper end of the first steel pipe pile 11 by a known method. In addition, the portion of the first steel pipe 2 that spans the slope S is covered with a cylindrical retaining wall 13. The upper part of the retaining wall 13 is expanded downward to prevent soil from accumulating.

<Second steel pipe>
The second steel pipe 3 shown in FIG. 1A is arranged parallel to the first steel pipe 2. The second steel pipe 3 has the same material, diameter, and thickness as the first steel pipe 2. The first steel pipe 2 and the second steel pipe 3 are spaced apart from each other in the radial direction (that is, horizontal direction) of the first steel pipe 2.

The second steel pipe 3 includes a first end portion 31 constituting a lower end portion, a second end portion 32 constituting an upper end portion, a first filled portion 33, a second filled portion 34, and a first non-filled portion 35. and a second non-filled portion 36.

The first filled part 33, the second filled part 34, the first unfilled part 35, and the second unfilled part 36 of the second steel pipe 3 are the first filled part 23, the second filled part 24, This is the same as the first non-filled portion 25 and the second non-filled portion 26.

In other words, the hollow portion of the second steel pipe 3 is filled with concrete 10 in at least a portion in the axial direction. Further, the second steel pipe 3 is filled with concrete 10 at least in the vicinity of the first end 31.

Furthermore, as shown in FIG. 2, the first non-filled portion 35 includes a portion of the second steel pipe 3 where the bending moment M2 acting on the second steel pipe 3 becomes zero when a load F in the axial direction of the beam 4 is applied to the connection portion of the second steel pipe 3 with the beam 4.

When installing the utility pole 1, the lower end of the second steel pipe 3 is connected to the upper end of the second steel pipe pile 12. In addition, the portion of the second steel pipe 3 that straddles the slope S is covered with a cylindrical earth retainer 14 similar to the first steel pipe 2 .

<Beam>
The beam 4 connects the first steel pipe 2 and the second steel pipe 3 in the radial direction of the first steel pipe 2. As shown in FIG. 4, the beam 4 has a main body 41 made of a steel pipe, and a first connecting part 42 and a second connecting part 43 attached to the ends of the main body 41, respectively.

In the main body 41, the hollow parts of the first filling part 44 to which the first connecting part 42 is fixed and the second filling part 45 to which the second connecting part 43 is fixed are filled with concrete. In other words, the hollow portion of the beam 4 is filled with concrete in at least a portion in the axial direction. An unfilled portion 46 that is not filled with concrete is provided between the first filled portion 44 and the second filled portion 45.

The first connecting portion 42 is a coupling member that connects one end of the main body 41 and the first steel pipe 2. The second connecting portion 43 is a coupling member that connects the other end of the main body 41 and the second steel pipe 3.

＜Arm band＞
The first cross arm 5 is fixed in the vicinity of the second end 22 of the first steel pipe 2. The second cross arm 6 is fixed in the vicinity of the second end 32 of the second steel pipe 3. An AT feeder (AF) and an AT protection wire (PW) are arranged on the first cross arm 5 and the second cross arm 6, respectively.

<Bracket>
The first bracket 7 is fixed to the first steel pipe 2 at a position below the beam 4. The second bracket 8 is fixed to the second steel pipe 3 at a position below the beam 4. The first bracket 7 and the second bracket 8 each hold an overhead wire that supplies electricity to railway cars passing below.

[1-2. Production method]
Next, a method for manufacturing the utility pole 1 will be described. As shown in FIG. 5, the utility pole manufacturing method of this embodiment includes a concrete filling step S10 and a beam connecting step S20.

<Concrete filling process>
In this step, concrete is filled into the hollow portions of at least a portion of each of the first steel pipe 2, the second steel pipe 3, and the beam 4 in the axial direction.

In the first steel pipe 2, first, a portion that will become the first filling portion 23 is filled with concrete. Next, a mesh is placed at the boundary between the portion that will become the second filled portion 24 and the first non-filled portion 25 . After arranging the mesh, concrete before hardening is poured into the hollow part of the first steel pipe 2, so that only the part that will become the second filling part 24 is filled with concrete. In the second steel pipe 3 as well, concrete is filled in a portion that will become the first filling portion 33 and a portion that will become the second filling portion 34 using the same procedure.

For example, in the beam 4, concrete is first filled into the area that will become the first filled section 44. Next, a mesh is placed at the boundary between the area that will become the second filled section 45 and the unfilled section 46, and then pre-hardened concrete is poured in.

This allows the formation of hollow sections, in which concrete is filled, and non-filled sections, in which concrete is not filled, at low cost in the first steel pipe 2, the second steel pipe 3, and the beam 4.

<Beam connection process>
In this step, after the concrete poured into the hollow part hardens, the beam 4 is connected to the first steel pipe 2 and the second steel pipe 3. Note that the beam 4 may be connected after the first steel pipe 2 and the second steel pipe 3 are stood on the ground.

[1-3. Effects]
According to the embodiment described above in detail, the following effects can be obtained.
(1a) The concrete 10 filled in the hollow portion improves the restraining force of the first steel pipe 2 and the second steel pipe 3. Therefore, the pipe diameter and thickness of each of the first steel pipe 2 and the second steel pipe 3 can be reduced while maintaining the strength of the utility pole 1 by using the inexpensive concrete 10. As a result, the cost of the utility pole 1 is reduced.

(1b) By filling the first steel pipe 2 and the second steel pipe 3 near their first ends with concrete 10, the strength of the lower ends of the first steel pipe 2 and the second steel pipe 3, where relatively large loads and moments act, can be increased. This can facilitate the reduction of the pipe diameter and thickness of the first steel pipe 2 and the second steel pipe 3.

(1c) Since the first steel pipe 2 and the second steel pipe 3 each have an unfilled portion, concrete is selectively filled in the portion that requires high strength. This makes it possible to suppress increases in material costs and weight of the utility pole 1.

(1d) By filling the connection parts of the first steel pipe 2 and the second steel pipe 3 with concrete, the strength of the connection parts of the first steel pipe 2 and the second steel pipe 3 with the beam 4, where relatively large loads and moments act, can be increased. This can facilitate the reduction of the pipe diameter and thickness of each of the first steel pipe 2 and the second steel pipe 3.

(1e) In each of the first steel pipe 2 and the second steel pipe 3, concrete is not filled in the areas where the bending moment is zero, so that the amount of concrete filled in the areas where the required bending strength is relatively low can be reduced. Therefore, the material cost and weight of the utility pole 1 can be reduced while suppressing the decrease in the strength of the utility pole 1.

(1f) By reducing the diameter and thickness of the first steel pipe 2 and the second steel pipe 3, the foundation portion that supports the utility pole 1 (that is, the first steel pipe pile 11 and the second steel pipe pile 12) can be downsized. . As a result, the installation cost of the utility pole 1 is reduced.

[2. Other embodiments]
Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above embodiments and can take various forms.

(2a) In the utility pole 1 of the above embodiment, the beam 4 does not necessarily have to be filled with concrete. Also, the shape of the beam 4 described above is an example. For example, the beam 4 may have a main body 41A with curved ends as shown in FIG. 6A.

Furthermore, the beam 4 may have a first connecting portion 42B and a second connecting portion 43B extending downward from the two axial ends of the main body 41B, respectively, as shown in FIG. 6B. The first connecting portion 42B is connected to the first steel pipe 2 in the radial direction of the first steel pipe 2. The second connecting portion 43B is connected to the second steel pipe 3 in the radial direction of the second steel pipe 3.

(2b) In the utility pole 1 of the above embodiment, each of the first steel pipe 2 and the second steel pipe 3 does not necessarily need to be filled with concrete 10 in the vicinity of the first end. Moreover, the first steel pipe 2 and the second steel pipe 3 do not necessarily need to be filled with concrete 10 at the connection portions with the beams 4, respectively.

(2c) In the utility pole 1 of the above embodiment, the first steel pipe 2 and the second steel pipe 3 may each be filled with concrete 10 over the entire axial direction. In other words, the first steel pipe 2 and the second steel pipe 3 may each not have an unfilled portion.

(2d) The utility pole 1 of the above embodiment does not necessarily have to include the second steel pipe 3 and the beam 4. That is, utility poles that include only one steel pipe are also within the intended scope of this disclosure. Furthermore, the utility pole of the present disclosure can also be used for power supply applications other than railway vehicles.

(2e) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. In addition, part of the configuration of the above embodiments may be omitted. In addition, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical ideas identified from the wording of the claims are embodiments of the present disclosure.

[3. Example]
Below, the contents and evaluation of tests conducted to confirm the effects of the present disclosure will be explained.

The design bending strength (Mud) and yield bending moment (Myd) were calculated for the steel pipes of Examples 1-5 and Comparative Examples 1 and 2 shown in Table 1. Example 1-5 has a concrete-filled steel pipe structure (CFT) in which a steel pipe is filled with concrete. Comparative Examples 1 and 2 are steel pipes that are not filled with concrete. "Strength" in Table 1 indicates the strength of the concrete filled in the steel pipe.

According to the results in Table 1, the steel pipe of the embodiment (i.e., CFT) has larger Mud and Myd than the steel pipe of the comparative example with the same diameter and thickness. For example, the same steel pipe is used in embodiment 1 and comparative example 1, but both Mud and Myd are larger in embodiment 1.

In other words, the steel pipe of the embodiment can exhibit the same degree of strength while having a smaller diameter and thickness than the steel pipe of the comparative example. For example, the steel pipe of the embodiment 3 has Mud and Myd equal to or greater than those of the comparative example 1, but the diameter and thickness of the steel pipe are smaller than those of the comparative example 1.

Reference Signs List 1... utility pole, 2... first steel pipe, 3... second steel pipe, 4... beam, 5... first arm, 6... second arm,
7...first bracket, 8...second bracket, 10...concrete, 11...first steel pipe pile,
12... second steel pipe pile, 21... first end portion, 22... second end portion, 23... first filling portion,
24... second filled portion, 25... first non-filled portion, 26... second non-filled portion, 31... first end portion,
32... second end portion, 33... first filled portion, 34... second filled portion, 35... first non-filled portion,
36: second non-filled portion, 41: main body, 41A: main body, 41B: main body, 42: first connecting portion,
42B...first connecting portion, 43...second connecting portion, 43B...second connecting portion, 44...first filling portion,
45...second filled section, 46...non-filled section.

Claims (7)

A first steel pipe having a hollow portion filled with concrete in at least a portion of its axial direction;
A second steel pipe arranged in parallel with the first steel pipe and having a hollow portion filled with concrete in at least a part of the axial direction;
A beam connecting the first steel pipe and the second steel pipe in a radial direction of the first steel pipe ,
The first steel pipe and the second steel pipe are each filled with the concrete at least at a connection portion with the beam.
Electric pole. 2. The utility pole according to claim 1,
The first steel pipe is filled with the concrete at least near a first end in the axial direction. The utility pole according to claim 1 or claim 2,
The first steel pipe is a utility pole having an unfilled portion in which the hollow portion is not filled with the concrete. The utility pole according to any one of claims 1 to 3 ,
A portion of the first steel pipe where the bending moment acting on the first steel pipe becomes zero when a load in the axial direction of the beam is applied to a connection portion of the first steel pipe with the beam; Of the two steel pipes, the concrete is placed in a portion where the bending moment acting on the second steel pipe becomes zero when a load in the axial direction of the beam is applied to the connection portion of the second steel pipe with the beam. A utility pole with an unfilled section. A step of filling a hollow portion with concrete in at least a portion of the axial direction of the first steel pipe and the second steel pipe ;
placing the first steel pipe and the second steel pipe parallel to each other;
a step of connecting a filled portion of the first steel pipe filled with the concrete and a filled portion of the second steel pipe filled with the concrete with a beam in the radial direction of the first steel pipe. The method for manufacturing a utility pole according to claim 5 ,
In the filling step, an unfilled portion in which the hollow portion is not filled with the concrete is formed in the first steel pipe and the second steel pipe . 7. The method for manufacturing a utility pole according to claim 6 ,
In the filling step, a mesh is placed at the boundary of the unfilled portion, and then unhardened concrete is poured into the hollow portion.