Vibration compensation structure for steel tower structure

Abstract

To improve the earthquake resistance and wind resistance of an existing steel tower structure by attaching a vibration compensation structure to the steel tower structure with a simple structure and easy construction.SOLUTION: A steel brace, consisting of an upper diagonal member 12 and a lower diagonal member 13, one support end of which is supported by a column fixing portion 20 friction-joined to a main column material 2 of a tower structure 1, and the other support end of which is supported by a friction damper 30 slidable against the outer circumferential surface of the main column material 2, and an extending arm 11 connecting these, is constructed along the axial direction of the main column material 2 as a vibration compensation structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vibration compensation structure for a steel tower structure, and more particularly to a vibration compensation structure for a steel tower structure that is attached to a part of an existing steel tower structure in order to improve the earthquake resistance and wind resistance of the steel tower structure. [Background technology]

[0002] In recent years, high-rise steel tower structures, such as communication towers and power transmission towers, are being required to have earthquake resistance in addition to the conventional wind resistance. In order to improve the earthquake resistance and wind resistance of existing steel tower structures, research and proposals have been made on retrofitting existing steel tower structures with vibration control or adding vibration compensation and forcing structures (Non-Patent Document 1, Patent Document 1). Note that in this specification, vibration control and vibration control are treated as almost synonymous terms from the perspective of the earthquake resistance performance of structures.

[0003] Both the test specimen for research into seismic retrofitting disclosed in Non-Patent Document 1 and the invention relating to a vibration control structure disclosed in Patent Document 1 are equipped with a vertical shear link type vibration control structure (vibration control mechanism) in which a viscous damper (C-type damper) or an MC type damper in which a C-type damper and a dynamic mass are arranged in parallel is incorporated into part of a steel brace structure attached externally to the lower part of the main pillar material of a steel tower structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-157495 A [Non-patent literature]

[0005] [Non-Patent Document 1] Yusuke Kawachi and 5 others, "Research on seismic retrofit using vertical shear link system", [online], December 2, 2020, 64th Academic Lecture Meeting of the College of Science and Technology, Nihon University, 2020, [Retrieved August 22, 2023], Internet: Top page<https: / / www.cst.nihon-u.ac.jp / research / gakujutu / 64 / index.html> Summary of the Invention [Problem to be solved by the invention]

[0006] In the vibration control structures (vibration control mechanisms) of Non-Patent Document 1 and Patent Document 1, it is necessary to incorporate a highly functional damper along the axial direction instead of the diagonal members of the externally attached steel brace structure. In addition, the steel tower structure for vibration control retrofitting disclosed in Non-Patent Document 1 is a test specimen of a size that allows experiments by reducing the actual structure, so that part of the main material is replaced with a coil spring to match the axial rigidity with the actual structure, resulting in a structure that is different from existing structures. As such, the structure is not applicable to existing structures.

[0007] In addition, the vibration control structure disclosed in Patent Document 1 is intended to be applied to an actual structure. In that case, in order to attach steel braces or oil dampers to the main pillars of an existing steel tower structure, welding work at a high altitude is required to attach joints such as gusset plates to parts of the existing main pillars. In addition to the need to ensure welding quality in the welding work, temporary scaffolding needs to be cured to specifications higher than those for normal scaffolding construction in order to prevent problems caused by the use of fire.

[0008] Therefore, the object of the present invention is to provide a vibration compensation structure for a tower structure that solves the problems associated with the above-mentioned conventional technology, utilizes some of the components of an existing structure as a vibration-damping structure, and enables the components of the vibration-damping structure to be easily attached and constructed to the existing structure. [Means for solving the problem]

[0009] The vibration compensation structure for a steel tower structure of the present invention is characterized in that a steel brace is constructed along the axial direction of the main pillar material, the brace having one support end supported by a pillar fixing part that is friction-joined to the main pillar material of the steel tower structure, and the other support end supported by a friction damper that can slide against the outer peripheral surface of the main pillar material.

[0010] It is preferable that the pillar fixing portion comprises a cylindrical member assembled in close contact with the outer peripheral surface of the main pillar.

[0011] It is preferable that the friction damper consists of a cylindrical member assembled so as to be slidable against the outer peripheral surface of the main pillar material, and that the friction damper slides against the main pillar material in response to input seismic motion to control vibration of the tower structure.

[0012] It is preferable that the cylindrical member has a friction material attached to its inner circumferential surface, the friction material being divided into a plurality of pieces in the longitudinal direction of the cylindrical member.

[0013] The cylindrical member is preferably assembled by joining half cylindrical members using high strength bolt fastening means.

[0014] It is preferable that the outer peripheral surface of the main pillar material is roughened in the area where the pillar material fixing member is in close contact.

[0015] It is preferable that the outer peripheral surface of the main pillar material, including the area in which the friction damper slides, is covered with a sliding surface plate.

[0016] The high strength bolt fastening means preferably has a bolt axial force adjusting member. Effect of the Invention

[0017] According to the present invention, in a steel tower structure, existing structural members can be utilized as part of the vibration-damping members, and the vibration-damping members and fixing members can be easily installed and constructed, thereby achieving the effect of reducing equipment costs and construction costs. [Brief description of the drawings]

[0018] [Figure 1] 1A is a schematic front view showing the overall shape of a steel tower structure equipped with a vibration compensation and forcing structure of the present invention, and FIG. 1B is a schematic cross-sectional view taken along the line Ib-Ib in plan view. [Diagram 2] FIG. 4 is a partially enlarged front view of a tower structure showing the area where the vibration compensation structure is attached. [Diagram 3] FIG. 4 is a partially enlarged view showing the pillar fixing portion of the vibration compensation and forced vibration structure. [Figure 4] A cross-sectional view showing the cross section of the pillar and the pillar fixing part along the IV-IV cross-sectional line (Figure 3). [Diagram 5] An explanatory diagram showing the state in which the components of the pillar fixing part are joined and fixed to the pillar. [Figure 6] FIG. 4 is a partially enlarged view showing a friction damper part of the vibration compensation structure. [Figure 7] Cross-section of the pillar and friction damper shown along section line VII-VII (Fig. 6). [Figure 8] FIG. 13 is an explanatory diagram showing how the components of the friction damper are joined and fixed to a pillar material. [Figure 9] 4 is a hysteresis curve graph showing an example of the restoration characteristic of a friction damper of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the vibration compensation structure for a tower structure of the present invention will be described with reference to the attached drawings.

[0020] Fig. 1 is a schematic diagram showing the front shape, planar cross-sectional shape, and arrangement of the overhanging arms 11 of the vibration compensation and forcing structure of an embodiment of the present invention. Fig. 2 is an enlarged view of the portion of the tower structure 1 (hereinafter simply referred to as tower 1) in Fig. 1 where the vibration compensation and forcing structure 10 is attached.

[0021] The steel tower 1 to which the vibration compensation and forcing structure 10 shown in each of Figures 1 and 2 is attached has a frame truss structure with hollow steel pipes as its constituent members, and high-tensile steel pipes for steel towers (STKT590) of specified dimensions are used for the main constituent members, including the main pillar members 2 arranged at the four corners of the steel tower 1, which is rectangular in plan view. The steel tower 1 has four main pillar members 2 erected on independent concrete foundations 5, each main pillar member 2 being a main constituent member, with horizontal members 4 and diagonal members 3 regularly joined in the height direction, and constructed as a stable tower-like frame truss structure as a whole.

[0022] The vibration compensation structure 10 installed on the existing steel tower structure 1 is attached to a lower level of the main pillar material 2 of the steel tower 1 so that each component of the steel brace structure (described later) is included within each vertical plane that radiates from the planar center C of the steel tower 1 to the main pillar materials 2 at the four corners, as shown in Figures 1(a) and (b).

[0023] The vibration compensation and forcing structure 10 of the present invention, as shown enlarged in Fig. 2, is composed of a steel brace structure supported by a main column material 2 of a steel tower 1. The vibration compensation and forcing structure 10 is composed of an overhanging arm 11, the base of which is fixed and held to the main column material 2 so as to overhang outward from the main column material 2 (see Fig. 1(b)), an upper diagonal member 12 whose lower end is joined to the tip side of the overhanging arm 11, a column fixing part 20 which fixes and holds the upper end of the upper diagonal member 12 to the main column material 2, a lower diagonal member 13 whose upper end is joined to the tip side of the overhanging arm 11, and a friction damper 30 which holds the lower end of the lower diagonal member 13 slidably on the main column material 2. The individual members are assembled on-site by bolting, and no welding is performed.

[0024] In this embodiment, a steel plate assembly plate with rib reinforcement is used for the extension arm 11, and hollow steel pipes of a predetermined member length are used for the upper diagonal member 12 and the lower diagonal member 13. The extension arm 11, the upper diagonal member 12, and the lower diagonal member 13 are joined by a U-shaped plate joint 14 (Fig. 3) that is joined by high-strength bolts via a splice plate (not shown) at the tip position of the extension arm 11. A hollow steel pipe with a short member length may be used for the extension arm 11. In addition, various joints that do not require on-site welding work (for example, flange joints, ribbed flange joints, U-shaped plate joints, and wing joints) can be selected and used as the means for joining the various members depending on the type and shape of the steel material used for each member.

[0025] [Structure of pillar fixing part] The configuration of the pillar fixing part 20 will be described with reference to Fig. 3 to Fig. 5. Fig. 3 shows an enlarged view of the pillar fixing part 20 of the vibration compensation and forcing structure 10. Fig. 4 shows a cross section of the pillar and the pillar fixing part 20 taken along the IV-IV cross section line (Fig. 3). Fig. 5 shows the components of the pillar fixing part 20 and the state in which they are joined and fixed to the pillar.

[0026] As shown in Figures 3 and 4, the column fixing part 20 is a processed steel pipe material consisting of a semi-cylinder member 22 with a roughly triangular gusset plate 21 formed on one side, and is constructed by integrating two semi-cylinder members 22 facing each other to form a cylindrical shape. As shown in Figure 3, the upper end of the upper diagonal member 12 is joined to the lower side of the gusset plate 21 by a high-strength bolt (not shown) with a splice plate (not shown) attached via a U-shaped plate joint 14.

[0027] A semi-cylindrical friction material 24 of a specified thickness is attached to the inner peripheral surface of each half-cylinder member 22, divided into three in the length direction and arranged side by side so as to cover the entire surface (Figs. 4 and 5). The inner diameter of the semi-cylindrical friction material 24 is equal to the diameter (outer diameter) of the main pillar material 2. As a result, when the two half-cylinder members 22 are faced to each other so as to sandwich the main pillar material 2, the outer peripheral surface of the main pillar material 2 and the inner peripheral surface of the friction material 24 are in close contact over the entire surface and frictionally bonded. An iron-based sintered metal material is suitable as the friction material.

[0028] As shown in Figs. 3 to 5, the column fixing part 20 is formed by placing two half-cylinder members 22 of the same shape facing each other across the main column member 2, and fastening them with high-strength bolts using bolt holes 25 formed in narrow flanges 23 along the sides, to form an overall configuration of a substantially cylindrical shape surrounding the outer periphery of the main column member 2. When the flanges 23 of the half-cylinder members 22 are joined together and fastened with multiple high-strength bolts 7, a disc spring washer 8 as a bolt axial force adjustment member is set on the bolt shaft to prevent a decrease in fastening force after fastening the bolts and the bolts from loosening. Here, it is necessary to adjust the bolt axial force so that a frictional force greater than or equal to the force acting on the column fixing part 20 can be exerted. In Fig. 5, only the bolts attached to the flanges on one side are drawn for the sake of simplicity.

[0029] On-site work on the main pillar material 2 side includes roughening work. That is, when the half-cylinder member 22 is attached to the main pillar material 2 to form the pillar material fixing part 20, in order to increase the degree of adhesion between the outer peripheral surface of the main pillar material 2 and the inner peripheral surface of the friction material 24 of the half-cylinder member 22 and to make a strong frictional joint, the area of ​​the outer peripheral surface of the main pillar material 2 where the half-cylinder member 22 comes into contact is roughened by blasting or the like to remove existing paint film, rust, etc.

[0030] [Friction damper configuration] The friction damper 30 has almost the same configuration as the pillar fixing part 20 shown in Fig. 3, and the method of attachment to the main pillar 2 is also almost the same, but the difference is that the pillar fixing part 20 is fixed to the main pillar 2 and does not slide, whereas the friction damper 30 does slide. The configuration of the friction damper 30 will be explained below with reference to Figs. 6 to 8. Fig. 6 shows an enlarged view of the friction damper 30 attached to the main pillar 2 of the vibration compensation structure 10. Fig. 7 shows a cross section of the main pillar 2 and the friction damper 30 along the VII-VII cross section line. Fig. 8 shows the components of the friction damper 30 and the state in which they are joined and fixed to the pillar.

[0031] The friction damper 30 is a processed steel pipe material consisting of a semi-cylindrical member 32 with a gusset plate 31 of a generally triangular shape with the lower side as the apex integrally formed on one side, and is constructed by integrating two semi-cylindrical members 32 facing each other to form a cylindrical shape. As shown in Fig. 6, the lower end of the lower diagonal member 13 is joined to the upper side of the gusset plate 31 via a ball seat joint 36. As for the joint between the lower diagonal member 13 and the friction damper 30, various joints can be used instead of the ball seat joint 36, as long as a pin structure that can realize smooth sliding action of the friction damper 30 can be constructed.

[0032] Furthermore, narrow flanges 33 are formed along both sides of the half-cylinder member 32 constituting the friction damper 30, and a row of bolt holes 35 is provided. Semi-cylindrical friction materials 34 similar to the pillar fixing part 20 are attached to the inner peripheral surface of the half-cylinder member, with the entire length of the cylindrical part of the pillar fixing part 20 divided into three in the length direction and lined up (Figs. 7 and 8).

[0033] Meanwhile, a stainless steel plate 9 serving as a sliding surface plate is tightly wrapped around and attached to the outer peripheral surface of the main pillar material 2 in a predetermined range above and below the range where the friction damper 30 of the main pillar material 2 is attached. For this reason, the inner diameter of the friction material 34 described above is set equal to the outer diameter of the range where the stainless steel plate 9 is attached. Considering the sliding characteristics of the friction damper 30, a resin-based material is suitable for the friction material 34, but various friction materials such as alloys with copper or the like having a low friction coefficient, metals containing resin, etc. can also be used for the sliding surface plate. In addition to the stainless steel plate 9, a metal plate or a synthetic resin plate having wear resistance can also be used for the sliding surface plate.

[0034] The method of attaching the friction damper 30 to the main pillar material 2 is almost the same as that of the pillar material fixing part 20. For example, as shown in Fig. 8, two identical half-cylinder members 32 are placed opposite each other, sandwiching the main pillar material 2 to which the stainless steel plate 9 is attached, and then joined with high-strength bolts using the bolt holes 35 formed in the flanges 33. Note that, for the sake of simplicity, only the bolts attached to the flange 33 on one side are shown in Fig. 8.

[0035] [Setting the sliding characteristics of the friction damper] The vibration damping function of the vibration compensation structure 10 of the present invention can be controlled by the sliding characteristics of the friction damper 30. That is, in the case of the friction damper 30, the property of being almost rigid-plastic is obtained against the input earthquake motion as shown in FIG. 9, but the friction force generated between the stainless steel plate 9 and the friction material 34 can be controlled by controlling the torque when fastening the bolts, and the damper performance (restoring performance) can be appropriately designed. For example, when fastening the half-cylinder member 32 constituting the friction damper 30 with a high-strength bolt, the strength and number of the disc spring washers 8 can be adjusted to change the bolt fastening force, thereby controlling the friction force between the friction damper 30 and the stainless steel plate 9. In addition, the surface of the stainless steel plate 9 can be adjusted, or metal materials with different friction coefficients can be used in combination to control the friction force.

[0036] In the above description of the present invention, the case where only the friction damper 30 performs the sliding action has been described as an example, but the friction coefficient of the friction material 24 of the column fixing part 220 may be adjusted to cause the sliding action and absorb energy. In addition, in Fig. 2, the column fixing part 20 is disposed at the top and the friction damper 30 is disposed at the bottom, but it goes without saying that they can be mounted upside down. Furthermore, the description has been given of hollow steel pipes as examples of the components of the tower 1, such as the main column material 2, diagonal members 3, and horizontal members 4, but it goes without saying that the present invention can also be applied to the case of a tower 1 in which a concrete-filled steel pipe (MC steel pipe) is used for the main column material 2.

[0037] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims. In other words, the technical scope of the present invention also includes embodiments obtained by combining technical means that are appropriately modified within the scope of the claims. [Explanation of symbols]

[0038] 1. Steel tower structure (steel tower) 2 Main pillar material 3 Diagonals 4 Horizontal material 6 Roughing 7 High strength bolts 8 Disc spring washer 9 Stainless steel plate 10. Compensating vibration structure 11 Extension arm 12 Upper diagonal member 13 Lower diagonal member 20 Pillar fixing part 21,31 Gusset plate 22,32 Semi-cylinder member 24,34 Friction material

Claims

1. A vibration compensation structure for a steel tower structure, characterized in that a steel brace is constructed along the axial direction of the main pillar material, the brace having one support end supported by a pillar fixing part that is friction-joined to the main pillar material of the steel tower structure, and the other support end supported by a friction damper that can slide against the outer peripheral surface of the main pillar material.

2. The vibration compensation structure for a steel tower structure as described in claim 1, wherein the pillar fixing portion is made of a cylindrical member assembled in close contact with the outer peripheral surface of the main pillar material.

3. The friction damper is a cylindrical member assembled so as to be slidable against the outer peripheral surface of the main pillar material, and the friction damper slides against the main pillar material in response to input seismic motion to control the vibration of the tower structure.

4. 4. The vibration compensation structure for a tower structure according to claim 2 or 3, wherein the cylindrical member has an inner peripheral surface to which a friction material divided into a plurality of pieces is attached in the longitudinal direction of the cylindrical member.

5. 5. The vibration compensation structure for a steel tower structure according to claim 4, wherein the cylindrical members are assembled by joining half cylindrical members using high-strength bolt fastening means.

6. The vibration compensation structure for a steel tower structure according to claim 1 or 2, wherein the outer peripheral surface of the main pillar material is roughened in the area where the pillar material fixing portion is in close contact with the main pillar material.

7. The vibration compensation structure for a steel tower structure according to claim 1 or 3, wherein the outer peripheral surface of the main pillar material, including the area in which the friction damper slides, is covered with a sliding surface plate.

8. The vibration compensation structure for a steel tower structure according to claim 5, wherein the high-strength bolt fastening means has a bolt axial force adjustment member.

Images