Column structure

Abstract

The present invention provides a support column structure that can reduce stress concentration at the upper end of the cylindrical body connecting the base plate and the support column. [Solution] The support structure comprises a support column 1 extending vertically in the Z direction, a base plate 3 having bolt holes 30 and to which the lower end portion 42 of the support column 1 is fixed, and an outer cylindrical body 4 formed in a cylindrical shape and to which the support column 1 is positioned. The upper end portion 40 of the outer cylindrical body 4 is fixed to the support column 1. The lower end portion 42 of the outer cylindrical body 4 is fixed to the base plate 3. The upper end portion 40 of the outer cylindrical body 4 has a plurality of peaks 40a and a plurality of valleys 40b. The plurality of peaks 40a and the plurality of valleys 40b are arranged alternately with respect to each other in the circumferential direction of the support column 1. Through holes 43 are formed in each of the plurality of peaks 40a of the outer cylindrical body 4, which open the outer circumferential surface of the support column 1.

Description

Technical Field

[0001] The present disclosure relates to a column structure of a column to which attachments such as road lighting, lighting devices, traffic signals, road signs, and electric bulletin boards are attached.

Background Art

[0002] A column to which attachments such as road lighting, lighting devices, traffic signals, road signs, and electric bulletin boards are attached has a column extending in the vertical direction and a base plate to which the lower end of the column is welded and fixed. The base plate is a flat plate member extending in the horizontal direction, and bolt holes are formed at a plurality of locations around the column. The base plate is fastened by passing an anchor bolt through the bolt hole of the base plate in a state where it is placed on the road surface or the installation surface of the structure, or by passing a bolt through the bolt hole of the base plate in a state where it is placed on the installation surface of the flange of another column.

[0003] Improvement in fatigue performance against repeatedly acting bending loads is required for the connection portion between the column and the base plate. In Patent Document 1, a cylindrical body as a reinforcing structure for connecting the base plate and the column is provided, and by forming the upper end surface of the cylindrical body into a gentle uneven surface formed by a continuous curved surface, stress concentration when a bending load acts on the column is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides a column structure capable of reducing stress concentration at the upper end portion of a cylindrical body connecting a base plate and a column.

Means for Solving the Problems

[0006] The support structure of the present disclosure comprises a vertically extending support column, a base plate having bolt holes and to which the lower end of the support column is fixed, and an outer cylinder formed in a cylindrical shape and in which the support column is disposed inside the cylinder, wherein the upper end of the outer cylinder is fixed to the support column and the lower end of the outer cylinder is fixed to the base plate, the upper end of the outer cylinder has a plurality of peaks and a plurality of valleys, the plurality of peaks and the plurality of valleys are arranged alternately with respect to each other in the circumferential direction of the support column, and each of the plurality of peaks in the outer cylinder has a through hole formed therein that opens the outer circumferential surface of the support column. [Brief explanation of the drawing]

[0007] [Figure 1] This is a side view showing the support column of the first embodiment provided on the installation surface and the attachment attached to the support column. [Figure 2] This is a perspective view showing the structure of the lower end of the support column. [Figure 3] This is a front view showing the structure of the lower end of the support column. [Figure 4] This is a cross-sectional view showing the area indicated by the A1-A1 arrow in Figure 3. [Figure 5] This is a plan view showing the structure of the lower end of the support column. [Figure 6] This figure shows the preferred relationship between the peaks, valleys, and through holes that constitute the upper end of the outer cylinder. [Figure 7] This is a front view showing the structure of the lower end of the support column in the second embodiment. [Figure 8] This figure shows the FEM simulation results for Comparative Examples 1 and 2 and Examples 1 and 2, as well as the stress values ​​generated in each part of the support structure. [Modes for carrying out the invention]

[0008] <First Embodiment> A first embodiment of this disclosure will be described with reference to the drawings. Figure 1 is a side view showing the support column 1 and attachment 2 attached to the support column 1 of the first embodiment, which are installed on the installation surface Ro1. Figure 2 is a perspective view showing the structure of the lower end portion 42 of the support column 1. Figure 3 is a front view showing the structure of the lower end portion 42 of the support column 1. Figure 4 is a cross-sectional view showing the area indicated by the A1-A1 arrow in Figure 3. Figure 5 is a plan view showing the structure of the lower end portion 42 of the support column 1. Figure 6 is a diagram showing the preferred relationship between the peak portion 40a, the valley portion 40b, and the through hole 43 that constitute the upper end portion 40 of the outer cylindrical body 4. The upper part of the support column 1 is not shown in Figures 2 to 5. In Figures 1 to 4 and Figure 6, the downward direction in the vertical direction Z is indicated by Z1, and the upward direction is indicated by Z2.

[0009] As shown in Figure 1, the support column 1 is formed in a cylindrical shape with a perfect circle in cross-section and extends vertically in the Z direction. A mounting 2, which serves as road lighting and lighting equipment, is attached to the upper part of the support column 1. The lower part of the support column 1 is fastened and fixed to the installation surface Ro1 on the road surface using anchor bolts (not shown). Specifically, as shown in Figures 1 to 3, the lower part of the support column 1 has a flat base plate 3 that extends horizontally perpendicular to the pipe axis of the support column 1. The base plate 3 is fastened with anchor bolts (not shown) through bolt holes 30 formed in the base plate 3 and fastening members (not shown) such as nuts.

[0010] As shown in Figure 4, the lower part of the support column 1 is welded to the base plate 3. The base plate 3 has an insertion hole 31 that is sized to accommodate the support column 1. When the support column 1 is inserted into the insertion hole 31, the lower end of the support column 1 and the inner surface of the insertion hole 31 are welded together, and the support column 1 is fixed to the base plate 3 by the welded joint P1.

[0011] As shown in Figures 2-4, a cylindrical outer body 4 is provided. A support column 1 is positioned inside the outer body 4, and the outer body 4 surrounds the corner between the support column 1 and the base plate 3. The upper end portion 40 of the outer body 4 is welded to the support column 1. For example, as shown in Figure 4, the upper end surface 41 of the outer body 4 and the outer circumferential surface of the support column 1 are fixed by a weld P2. As shown in Figures 2-4, the lower end portion 42 of the outer body 4 is welded to the base plate 3. For example, as shown in Figure 4, the lower end portion 42 of the outer body 4 is welded to the base plate 3 by an outer weld P3 and an inner weld P4. The fixing strength is improved by welding from both the inner and outer radial sides of the outer body 4.

[0012] As shown in Figures 2-4, the upper end portion 40 of the outer cylindrical body 4 has a plurality of peaks 40a and a plurality of valleys 40b. The plurality of peaks 40a and a plurality of valleys 40b are repeatedly arranged relative to each other in the circumferential direction of the support column 1. As a result, the upper end surface 41 of the outer cylindrical body 4 is formed in a wavy shape that undulates in the vertical direction, resulting in an uneven surface. In the first embodiment, four peaks 40a are formed in the circumferential direction of the support column 1, but the number of peaks 40a is not limited to this. For example, there may be three or more. For example, the number of peaks 40a may be four or more and eight or less.

[0013] In the above configuration, it was found that stress tends to concentrate at the uppermost ends of the multiple peaks 40a. Therefore, as shown in Figures 2 to 4, through holes 43 are formed in each of the multiple peaks 40a, leaving the outer circumferential surface of the support column 1 open. By forming the through holes 43, stress can be distributed, and it is possible to suppress the concentration of stress at the upper ends of the multiple peaks 40a. The through holes 43 are located Z1 below the upper end surface 41 of the outer cylindrical body 4, and the through holes 43 do not open into the upper end surface 41 of the outer cylindrical body 4. In the first embodiment, the bottoms of the multiple valleys 40b are located at the same height as each other, and the through holes 43 are located higher than the horizontal plane connecting the bottoms of the valleys 40b. The edge of the through hole 43 and the outer circumferential surface of the support column 1 are welded and fixed by a welded joint P5 (see Figure 4).

[0014] As shown in Figure 6, if the dimension of the peak 40a along the circumferential direction of the support column 1 is L1, the height H1 of the peak 40a (depth of the valley 40b) may be (L1 / 4) or greater and (L1 / 0.5) or less. The horizontal dimension W1 of the through hole 43 along the circumferential direction of the support column 1 may be (L1 / 2) or greater and (L1 / 1.1) or less. The vertical dimension D1 of the through hole 43 may be (L1 / 2) or greater and (L1 / 1.1) or less. These values ​​are preferred ranges, but are not limited to them.

[0015] As shown in Figure 4, the lower end portion 42 of the outer cylinder 4 widens radially outward from the support column 1 as it moves from the top Z2 downward Z1. A portion of the inner circumferential surface of the lower end portion 42 of the outer cylinder 4 is separated from the outer circumferential surface of the support column 1, and the distance between the inner circumferential surface of the lower end portion 42 of the outer cylinder 4 and the outer circumferential surface of the support column 1 gradually increases as it moves from the top Z2 downward Z1, forming a so-called trumpet shape. This makes it possible to suppress the concentration of stress at the lower end portion 42 of the outer cylinder 4.

[0016] As shown in Figure 3, the lower end 42a of the outer cylinder 4 is located at the outermost radial end. As shown in Figure 5, the lower end 42a of the outer cylinder 4 is circular (perfectly round) in plan view. The outer cylinder 4 does not have any members that protrude radially outward beyond the lower end 42a of the outer cylinder 4. This means, for example, that the support structure does not have radial ribs. Radial ribs extend from the radial inside to the outside of the support column 1, with the upper part of the radial ribs welded to the outer circumferential surface of the outer cylinder 4 and the lower part of the radial ribs welded to the base plate 3. In this way, since the outer cylinder 4 does not have any members that protrude radially outward beyond the lower end 42a of the outer cylinder 4, when fastening a bolt through the bolt hole 30 with a nut, the tool does not interfere with any protruding members such as ribs, making the fastening work easier.

[0017] <Second Embodiment> The support structure of the second embodiment will be described with reference to FIG. 7. FIG. 7 is a front view showing the structure of the lower end portion 42 of the support column 1 of the second embodiment. The support column structure of the second embodiment shown in FIG. 7 is different from the support column structure of the first embodiment shown in FIGS. 2 to 6 only in the shape of the lower end portion 42 of the outer cylinder 4. Specifically, as shown in FIG. 7, the lower end portion 42 of the outer cylinder 4 is configured such that the diameter does not change from the upper side Z2 to the lower side Z1, and the outer peripheral surface of the lower end portion 42 of the outer cylinder 4 is a vertical plane along the vertical direction Z. The lower end 42a of the outer cylinder 4 is welded and fixed to the base plate 3. Otherwise, the structure of the second embodiment is the same as that of the first embodiment.

[0018] [Effects of the present disclosure] Next, in order to show the effects of the present disclosure, static load simulations were performed on the support column structures of Comparative Examples 1 and 2 and Examples 1 and 2. The actual load is 100 MPa, and the size of the mesh of the FEM model is 5 mm. FIG. 8 is a diagram showing the models of the FEM simulation results for Comparative Examples 1 and 2 and Examples 1 and 2, and the values of the stresses generated in each part of the support column structure. In the diagram of the model, it is shown that the stress in the blue (close to black in the grayscale diagram) part is small, and the stress in the red (close to a bright color in the grayscale diagram) part is high.

[0019] Example 1 It is the support column structure of the second embodiment shown in FIG. 7. A plurality of peak portions 40a and a plurality of valley portions 40b at the upper end portion 40 of the outer cylinder 4 are alternately arranged in the circumferential direction of the support column 1, and the upper end surface 41 of the outer cylinder 4 is formed in a wavy shape that undulates in the vertical direction. A through hole 43 is formed in each of the plurality of peak portions 40a. That is, compared with Example 2 described later, the lower end portion 42 of the outer cylinder 4 is configured such that the diameter does not change from the upper side Z2 to the lower side Z1, and the outer peripheral surface of the lower end portion 42 of the outer cylinder 4 is a vertical plane along the vertical direction Z. Otherwise, it is the same as Example 2.

[0020] Example 2 Figures 2 to 5 show the support structure of the first embodiment. Multiple peaks 40a and multiple valleys 40b at the upper end 40 of the outer cylinder 4 are arranged alternately with respect to each other in the circumferential direction of the support column 1, and the upper end surface 41 of the outer cylinder 4 is formed in a wave-like shape that undulates in the vertical direction. Through holes 43 are formed in each of the multiple peaks 40a. The lower end 42 of the outer cylinder 4 is formed in a trumpet shape that widens radially outward from the support column 1 from the top Z2 downward Z1.

[0021] Comparative Example 1 This configuration is the same as in Example 1, except that the through holes 43 formed in each of the multiple peaks 40a are omitted.

[0022] Comparative Example 2 In contrast to Example 2, this configuration does not include the through holes 43 formed in each of the multiple peaks 40a. Otherwise, it is the same as Example 2.

[0023] Comparing Comparative Example 1 and Example 1 in the table shown in Figure 7, it can be seen that by forming through holes 43 in each of the multiple peaks 40a, the stress concentrated at the uppermost points of the multiple peaks 40a is reduced from 98 MPa to 75 MPa, demonstrating that stress concentration at the uppermost points of the multiple peaks 40a can be dispersed and reduced. Furthermore, comparing Comparative Example 2 and Example 2 in the table shown in Figure 7, it can be seen that by forming through holes 43 in each of the multiple peaks 40a, the stress concentrated at the uppermost points of the multiple peaks 40a is reduced from 105 MPa to 77 MPa, demonstrating that stress concentration at the uppermost points of the multiple peaks 40a can be dispersed and reduced.

[0024] Comparing Example 1 and Example 2 in the table shown in Figure 7, it can be seen that by forming the lower end 42 of the outer cylinder 4 into a so-called trumpet shape that widens radially outward, the stress concentrated at the lower end 42a of the outer cylinder 4 is reduced from 224 MPa to 56 MPa. This demonstrates that stress concentration at the lower end 42a of the outer cylinder 4 can be dispersed and reduced. In particular, in Example 2, stress is distributed at all points of the outer cylinder 4, including the uppermost end of the peaks 40a, the lower end of the through-hole 43, the lower end of the valleys 40b, and the lower end 42a of the outer cylinder 4, indicating improved fatigue performance.

[0025] <Variation> (A) In the above embodiment, as shown in Figure 5, the lower end 42a of the outer cylindrical body 4 is circular (perfect circle) in plan view, but it is not limited to a perfect circle. For example, it may be elliptical. In the above embodiment, as shown in Figure 5, the base plate 3 is square (rectangle) in plan view, but is not limited to this. For example, it may be rectangular in plan view. For example, if the lower end 42a of the outer cylinder 4 is elliptical in plan view and the base plate 3 is rectangular in plan view, then the longitudinal direction of the base plate 3 and the major axis of the ellipse may be considered to coincide.

[0026] (B) In the above embodiment, the mounting object 2 is not limited to road lighting or lighting devices. The mounting object 2 may be various structures or devices such as traffic lights, road signs, or electronic display boards.

[0027] (C) In the above embodiment, the base plate 3 is fastened by passing anchor bolts through the bolt holes 30 of the base plate 3 while it is placed on the road surface or the installation surface Ro1 of the structure. However, it is not limited to this. For example, the base plate 3 may be fastened by passing bolts through the bolt holes 30 of the base plate 3 while it is placed on the installation surface of the flange of another support column.

[0028] (D) In ​​the above embodiment, the lower end portion 42 of the outer cylinder 4 is welded and fixed from both the radially inner and outer sides, but is not limited to this. For example, it may be welded and fixed from only one side.

[0029] [1] As in the above embodiment, the support structure may include a support column 1 extending in the vertical direction Z, a base plate 3 having bolt holes 30 and to which the lower end portion 42 of the support column 1 is fixed, and an outer cylindrical body 4 formed as a cylinder and in which the support column 1 is arranged inside the cylinder, wherein the upper end portion 40 of the outer cylindrical body 4 is fixed to the support column 1, and the lower end portion 42 of the outer cylindrical body 4 is fixed to the base plate 3, and the upper end portion 40 of the outer cylindrical body 4 has a plurality of peaks 40a and a plurality of valleys 40b, the plurality of peaks 40a and the plurality of valleys 40b are arranged alternately with respect to each other in the circumferential direction of the support column 1, and each of the plurality of peaks 40a in the outer cylindrical body 4 has a through hole 43 that opens the outer circumferential surface of the support column 1. This configuration makes it possible to reduce the stress acting on the uppermost end of each of the multiple peaks 40a by distributing the stress.

[0030] [2] The support structure described in [1] above may be such that the lower end portion 42 of the outer cylindrical body 4 widens radially outward from the support column 1 as it moves from top to bottom. This configuration makes it possible to reduce the stress acting on the lower end 42a of the outer cylinder 4 by distributing it.

[0031] [3] The support structure described in [2] above may be such that the lower end 42a of the outer cylindrical body 4 is circular in plan view. In this context, "circular shape" includes not only perfect circles but also ellipses. With this configuration, compared to a shape in which a bent portion is included at the lower end 42a of the outer cylinder 4 in a plan view, it is possible to reduce the concentration of stress at the lower end 42a of the outer cylinder 4.

[0032] [4] The support structure described in [3] above may be such that the outer cylindrical body 4 does not have a member that protrudes radially outward from the lower end 42a of the outer cylindrical body 4. With this configuration, when fastening a bolt through a bolt hole 30 with a nut, the tool will not interfere with protruding members such as ribs, making the fastening work easier.

[0033] This disclosure is not limited in any way to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of this disclosure. [Explanation of Symbols]

[0034] 1: Strut 3: Base plate 4: Outer cylinder 30: Bolt holes 40: Upper end 40a: Yamabe 40b: Tanibe 42: Bottom end 42a: Bottom end 43: Through hole Z: Vertical direction

Claims

1. It comprises a vertically extending support column, a base plate having bolt holes and to which the lower end of the support column is fixed, and an outer cylinder formed as a cylinder and in which the support column is arranged inside the cylinder, The upper end of the outer cylinder is fixed to the support column, and the lower end of the outer cylinder is fixed to the base plate. The upper end of the outer cylindrical body has a plurality of peaks and a plurality of valleys, and the plurality of peaks and the plurality of valleys are arranged alternately with respect to each other in the circumferential direction of the support column. A support structure in which through holes are formed in each of the multiple peaks of the outer cylindrical body, thereby opening the outer circumferential surface of the support column.

2. The support column structure according to claim 1, wherein the lower end of the outer cylindrical body widens radially outward from the support column as it extends from top to bottom.

3. The support structure according to claim 2, wherein the lower end of the outer cylindrical body is circular in plan view.

4. The support structure according to claim 3, wherein the outer cylindrical body does not have a member that protrudes radially outward from the lower end of the outer cylindrical body.

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