Lighting fixture installation support and its design method

Abstract

To provide a lighting fixture installation support, which has sufficient strength for installing a lighting fixture, can be manufactured relatively easily without requiring a dedicated manufacturing device, and can also meet the requirements of government ordinances.SOLUTION: Provided is a support for installing a lighting fixture, consisting of a plurality of steel pipe columns 4-7 of different diameters joined vertically with the diameter increasing from higher to lower. The plurality of steel pipe columns 4-7 are welded together via through diaphragms 10 respectively, and the plate thicknesses of the through diaphragms are set so that the out-of-plane stress generated therein is equal to or less than the short-term allowable stress level, allowing a maximum misalignment of 50 mm on one side between the upper steel pipe column and the steel pipe column below it.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a support pole for installing lighting fixtures and a design method thereof, and more specifically to a support pole with a simple structure yet sufficient strength performance, which is used mainly for installing lighting fixtures in stadiums, soccer fields, etc., and a design method thereof. [Background technology]

[0002] Lighting equipment is essential for athletics stadiums, soccer fields, baseball stadiums, and other venues. Since each individual lighting fixture is quite heavy, the support poles used to install them must also be strong enough to support the fixtures. Typical lighting fixture support poles are specially shaped, with the entire pole or joints made of tapered steel pipes. Therefore, specialized manufacturing equipment is required for their manufacture. Furthermore, due to the limited number of manufacturers, costs are high and delivery times tend to be long.

[0003] Generally, lighting fixture installation poles are over 15m in height, and poles of this height are regulated as structures (reinforced concrete poles, etc.) under Article 88, Paragraph 1 of the Building Standards Act and Article 138, Paragraph 1, Item 2 of the Building Standards Act Enforcement Order (Cabinet Order). This type of pole does not have the same diameter along its entire length, with the lower members being larger in diameter than the upper members, but the above regulations stipulate that the misalignment of the welds at the joints (the difference between the reference surfaces of the base materials to be welded) should be 5mm or less.

[0004] Although it is common to use a through diaphragm to connect square steel pipe columns, this method is mainly used when connecting an H-shaped steel beam to a square steel pipe column, and is not a design method for connecting square steel pipe columns vertically (e.g., JP 2023-23809 A). There is also a proposal for a joint structure for steel columns with different diameters (JP 2000-8482 A), but this joint structure uses a specially shaped column core equivalent to a diaphragm, and is not common. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-23809 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-8482 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, conventional poles for installing general lighting fixtures require specialized manufacturing equipment, and because there are only a limited number of manufacturers, they are expensive and take a long time to deliver. The present invention has been made in consideration of these problems in the prior art, and it is an object of the present invention to provide a pole for installing lighting fixtures that has sufficient strength for installing lighting fixtures, can be manufactured relatively easily without the need for specialized manufacturing equipment, and also meets the requirements of the above government ordinance, and a design method thereof. [Means for solving the problem]

[0007] The invention described in claim 1 for solving the above problem is to connect a plurality of steel pipe poles each having a different diameter so that the diameter of the poles at the bottom is larger. Through the diaphragm Vertical weld joint and manufacture A support for installing lighting fixtures How to design And, The thickness of the through diaphragm of , and set so that the out-of-plane stress generated therein is below the short-term allowable stress level. It is characterized by: Confirm that the out-of-plane stress generated in the through diaphragm is below the short-term allowable stress using the following formula (1). Support for installing lighting equipment How to design is. TIFF0007828652000001.tif26170 Here iMy: Out-of-plane bending moment around the y-axis at point i (unit: Nmm) jMz: Out-of-plane bending moment around the z-axis at point j (unit: Nmm) iZy: Section modulus of the y-axis cross section at point i (unit: mm 3 ) jZz: Section modulus of the z-axis cross section at point j (unit: mm3 ) iQz: Out-of-plane shear force in the Z-axis direction at point i (unit: N) jQy: Out-of-plane shear force in the y-axis direction at point j (unit: N) iAy: Cross-sectional area of ​​the y-axis cross section at point i (unit: mm 2 ) jAz: cross-sectional area of ​​the z-axis cross section at point j (unit: mm 2 ) i: Any distance from the center of the diaphragm in the z-axis direction (positive in the direction of the compression flange) (unit: mm) j: Any distance from the center of the diaphragm in the y-axis direction (absolute value) (unit: mm) y-axis: direction perpendicular to the maximum wind direction of the lighting pole Z axis: Maximum wind direction of the lighting pole F: Allowable tensile stress of the diaphragm (unit: N / mm 2 ) [Effects of the Invention]

[0012] The lighting fixture installation support and its design method according to the present invention are as described above, and by joining the upper and lower steel pipe columns via a through diaphragm that is set to satisfy the above formula (1), it is possible to create a lighting fixture installation support that has sufficient strength to accommodate the installation of lighting fixtures without requiring dedicated manufacturing equipment. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing the overall configuration of a lighting fixture installation pole according to the present invention; [Figure 2] 1 is a perspective view showing the configuration of a through diaphragm of a lighting fixture installation pole according to the present invention; [Figure 3] 1 is a perspective view showing a method for elongating a square steel pipe column in a support for installing a lighting fixture according to the present invention. FIG. [Figure 4] 10A and 10B are diagrams showing a method for replacing an upper steel pipe in a support for installing a lighting fixture according to the present invention. [Figure 5] FIG. 1 shows classification of replacement plates. [Figure 6] FIG. 1 illustrates a modeled through diaphragm. [Figure 7] FIG. 10 is a diagram showing stresses generated in a modeled through diaphragm. [Figure 8] FIG. 10 is a diagram showing the out-of-plane bending moment of a through diaphragm. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention provides a detailed description of an embodiment of the present invention with reference to the accompanying drawings. A lighting fixture installation support pole according to the present invention is comprised of a plurality of steel pipe poles, each of which has a different diameter, joined vertically with the lower pole having a larger diameter. The steel pipe poles are welded together via through diaphragms, and the thickness of the through diaphragms is set so that the out-of-plane stresses generated therein are equal to or less than the short-term allowable stress level, thereby allowing a maximum misalignment of 50 mm on one side between the upper and lower steel pipe poles. The reason for allowing a maximum misalignment of 50 mm on one side is that it was considered optimal to maintain the upper limit (100 mm) of the thickness of the through diaphragms.

[0015] FIG. 1 is an overall structural diagram of a lighting fixture installation pole 1 according to the present invention. Among the multiple-stage steel pipe poles, the topmost is a circular steel pipe 4 with a top plate 3 for installing a lighting fixture 2 at its upper end, and the other three steel pipe poles are square steel pipes 5, 6, and 7. In the illustrated example, there are three stages of square steel pipes 5, 6, and 7, but there may also be two or four or more stages. In the illustrated example, the square steel pipe pole 6 is formed by joining two steel pipe poles 6a and 6b of the same diameter on all four sides with a splice plate 11 and high-strength bolts (see FIG. 3). This configuration is adopted when the pole is segmented for ease of manufacturing and transport and then joined at the installation site.

[0016] The cross section of each steel pipe column 4-7 is varied depending on the distance from the top so that the effective slenderness ratio is 200 or less. A column base plate 8 is attached to the lower end of the lowest square steel pipe column 7. The column base plate 8 and the through diaphragm 10 (described later) are made of SN490C, the strongest steel material standardized for architectural use, or an equivalent TMCP steel. One reason for using a square steel pipe column 7 for the lowest stage is that the foundation (column base plate 8) is generally rectangular, making it easier to align with the foundation. The square steel pipes 5 and 6 above it are aligned with the square steel pipe column 7. Furthermore, because the angle of the lighting may differ from the angle of the foundation, the steel pipe in the top stage, where the lighting fixture 2 is attached, is a circular steel pipe 4.

[0017] The circular steel pipe 4 and the square steel pipe 5, as well as the square steel pipes 5, 6, and 7, are welded together via through diaphragms 10. The welding is by full penetration welding. As mentioned above, the lighting fixture installation pole 1 is over 15 m in height and is subject to regulations under the Building Standards Act Enforcement Ordinance, which stipulates that the weld misalignment at the joint (the misalignment between the reference surfaces of the base materials to be welded) must be 5 mm or less.

[0018] The lighting fixture installation support pole 1 of the present invention changes its column cross section depending on the distance from the top so that the effective slenderness ratio is 200 or less, and the part where the column cross section changes is welded together via a through diaphragm 10. The members joined to the upper and lower sides of the through diaphragm 10 are allowed to have a maximum misalignment of 50 mm on each side, but this allowable range of misalignment conflicts with the above-mentioned Cabinet Order, so safety must be confirmed in accordance with the proviso stipulated in the notification of the above-mentioned Cabinet Order.

[0019] As a result of intensive research and development in order to comply with the above-mentioned Cabinet Order, the inventor discovered that by adopting a design method in which the plate thickness of the through diaphragm 10 is set so that the out-of-plane stress generated in the through diaphragm 10 is below the short-term allowable stress level, it is possible to make it fall under the proviso stipulated in the notification of the above-mentioned Cabinet Order, namely, "This does not apply if appropriate reinforcement is carried out so that the strength of the steel material in the connection part is greater than the strength of the part calculated based on the allowable stress levels for the long-term and short-term forces." This led to the completion of the present invention.

[0020] The design method is described in detail below. In the present invention, the reinforcement of the misalignment is performed by confirming that the through diaphragm 10 is within the short-term allowable stress against out-of-plane stress, and this confirmation is performed using equation (1) described later, and the plate thickness at each point of the through diaphragm 10 is set to satisfy equation (1). The design procedure for the through diaphragm 10 is as follows.

[0021] 1) Convert the circular steel pipe 4 and square steel pipe 5 into a cross section made up of four identical plates with equivalent cross-sectional area and section modulus (see Figure 4). To replace the square steel pipe 5, find b (width of the four plates: mm) and uD (depth of the rectangle formed by the four plates: mm) that satisfy the following conditions. TIFF0007828652000002.tif37170 The replacement of circular steel pipe 4 satisfies the following conditions: 3 Calculate (thickness of the 4 plates: mm), b (width of the 4 plates: mm), and uD (diameter of the rectangle formed by the 4 plates: mm). TIFF0007828652000003.tif36170

[0022] 2) Two sets of plates with their thickness direction parallel to the load direction are used as flanges, and two sets of plates with their width direction parallel are used as webs (see Figure 5).

[0023] 3) The through diaphragm 10 is placed on a simply supported beam in the horizontal load direction and the direction perpendicular to the horizontal load, which is supported by pins at the lower square steel pipe position (see Figure 6).

[0024] 4) For the simple beam in the load direction, the axial force acting on the flanges of the four plates that replaced the upper member is taken as the external force, and for the simple beam in the direction perpendicular to the load, the axial force acting on the webs of the four plates that replaced the upper member is taken as the load. The stress from the web is divided into the compression side and the tension side, and is considered to act on the compression side diaphragm and the tension side diaphragm, each with a width of half the effective width of the diaphragm (see Figure 7).

[0025] It is necessary to confirm that the combined bending stress and shear stress in the horizontal load direction and perpendicular direction is below the short-term allowable stress of the through diaphragm 10, which can be confirmed using the following formula (1). The stress generated in the through diaphragm 10 at each point on the through diaphragm 10 must satisfy formula (1).

[0026] TIFF0007828652000004.tif26170Here iMy: Out-of-plane bending moment around the y-axis at point i (unit: Nmm) jMz: Out-of-plane bending moment around the z-axis at point j (unit: Nmm) iZy: Section modulus of the y-axis cross section at point i (unit: mm 3 ) jZz: Section modulus of the z-axis cross section at point j (unit: mm 3 ) iQz: Out-of-plane shear force in the Z-axis direction at point i (unit: N) jQy: Out-of-plane shear force in the y-axis direction at point j (unit: N) iAy: Cross-sectional area of ​​the y-axis cross section at point i (unit: mm 2 ) jAz: cross-sectional area of ​​the z-axis cross section at point j (unit: mm 2 ) i: Any distance from the center of the diaphragm in the z-axis direction (positive in the direction of the compression flange) (unit: mm) j: Any distance from the center of the diaphragm in the y-axis direction (absolute value) (unit: mm) y-axis: direction perpendicular to the maximum wind direction of the lighting pole Z axis: Maximum wind direction of the lighting pole F: Allowable tensile stress of the diaphragm (unit: N / mm 2 )

[0027] The above iMy, jMz, iQz, and jQy can be calculated using the following formulas. TIFF0007828652000005.tif123170Here uL: The value obtained by subtracting the equivalent plate thickness ut' from the cross-sectional area uD of the upper member, which is a set of four identical plate materials arranged symmetrically about two axes. uL = uD - ut' (unit: mm) LL: The value obtained by subtracting the plate thickness Lt from the thickness LD of the lower square steel pipe LL = LD - Lt (single mm) NL: Column axial force at the examination height (unit: N) Nf: Axial force acting on the upper member flange due to bending moment around the y-axis at the examination height (unit: N) Nw: Axial force acting on the upper member web due to bending moment around the y-axis at the examination height (unit: N)

[0028] Using the above formula (1), it can be confirmed that the values ​​of the stress in the principal axis direction due to the bending moment around the y-axis iMy, the bending moment around the z-axis jMz, the shear force in the z-axis direction iQz, and the shear force in the y-axis jQy at any point (i, j) on the through diaphragm 10 do not exceed the allowable tensile stress of the diaphragm. Regarding this point, a structural performance evaluation has been obtained as an evaluation of the design method (ERI-K22004). [Industrial Applicability]

[0029] The lighting fixture installation support and its design method according to the present invention are as described above. By joining the upper and lower steel pipe columns via a through diaphragm that is set to satisfy a specified formula, it is possible to create a lighting fixture installation support that has sufficient strength to accommodate the installation of lighting fixtures without requiring dedicated manufacturing equipment, and the industrial applicability of this method is great. [Explanation of symbols]

[0030] 1 Support for lighting equipment installation 2. Lighting fixtures 3 Top Plate 4. Circular steel pipe columns 5, 6, 7 Square steel pipe columns 8 Column base plate 10 through diaphragm

Claims

[Claim 1] A method for designing a support for installing lighting fixtures, which is manufactured by welding together a plurality of steel pipe columns of different diameters vertically via through diaphragms so that the diameters of the columns in the lower tiers are larger, The plate thickness of the through diaphragm is set so that the out-of-plane stress generated therein is equal to or less than the short-term allowable stress level, A design method for a support for installing lighting fixtures, which confirms that the out-of-plane stress generated in the through diaphragm is below the short-term allowable stress level using the following formula (1). Here iMy: Out-of-plane bending moment around the y-axis at point i (unit: Nmm) jMz: Out-of-plane bending moment around the z-axis at point j (unit: Nmm) iZy: Section modulus of the y-axis cross section at point i (unit: mm 3 ) jZz: Section modulus of the z-axis cross section at point j (unit: mm 3 ) iQz: Out-of-plane shear force in the Z-axis direction at point i (unit: N) jQy: Out-of-plane shear force in the y-axis direction at point j (unit: N) iAy: Cross-sectional area of ​​the y-axis cross section at point i (unit: mm 2 ) jAz: cross-sectional area of ​​the z-axis cross section at point j (unit: mm 2 ) i: Any distance from the center of the diaphragm in the z-axis direction (the direction toward the compression flange is positive) (unit: mm) j: Any distance from the center of the diaphragm in the y-axis direction (absolute value) (unit: mm) y-axis: direction perpendicular to the maximum wind direction of the lighting pole Z axis: Maximum wind direction of the lighting pole F: Allowable tensile stress of the diaphragm (unit: N / mm 2 )

Images