JP4097886B2 - Steel pipe column base structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steel pipe column base structure to be erected.
In particular, for steel tube pillar base structures that are installed on the side of roads such as streets and elevated roads, or in parks, etc., and are used for lighting, signs, equipment installation such as cameras, microphones, speakers, etc. The steel pipe column can be prevented from collapsing even when the steel pipe column is cracked or broken by a lateral stress acting on the steel pipe column due to traffic vibration or the like.
[0002]
[Prior art]
Steel pipe columns hold relatively lightweight equipment such as lighting and signs at a height of several meters, and unlike general structural members for construction, a large load from above is not applied. For example, those with a thickness of about 3 to 6 mm are used as stipulated in the standards of road lighting equipment specifications of the Construction Electrical Engineering Association. The outer diameter is about 5 to 50 cm.
[0003]
Further, since the steel pipe column is used in a place exposed to wind and rain, repeated stress in the lateral direction is applied to the base portion by wind force, traffic vibration, or the like. And when such a load is applied, the design which can maintain sufficient intensity | strength so that it may break at the base part and a steel pipe column may not collapse is made. In general, the outer diameter of the steel tube column is a taper tube having a taper of about 1/100 to 1/75 and a tapered tip.
[0004]
A typical example of a conventional steel pipe column base structure is shown in FIG.
As shown in FIG. 2, a base plate 5 that supports the steel pipe column 1 is provided at the lower end portion of the steel pipe column 1. Here, the steel pipe column 1 is fitted and inserted into, for example, a hole drilled in the base plate 5 and welded at a location indicated by 2b in the circumferential direction. However, as a method of joining the steel pipe column 1 and the base plate 5, it goes without saying that the bottom portion of the steel pipe column 1 and the upper surface of the base plate 5 may be welded.
[0005]
The base plate 5 is provided with a required number of anchor mounting holes 6 for installation and fixing.
Furthermore, a required number of vertical ribs 4 are arranged in the vertical direction from the base plate 5 to the lower end of the steel pipe column 1. Since the vertical ribs 4 are required to have a structure capable of withstanding loads from four directions on the steel pipe column 1, at least four, and in some cases, six to eight are provided at equal intervals in the circumferential direction of the steel pipe column. In general, the vertical rib 4, the steel pipe column 1 and the base plate 5 are joined by welding.
[0006]
However, although not shown here, a simple base structure in which a steel pipe column and a base plate are simply joined may be employed when the applied load is small and there is no need for reinforcement using vertical ribs.
[0007]
[Problems to be solved by the invention]
However, due to the lateral load that is constantly and repeatedly applied by wind power, traffic vibrations, etc., fatigue will accumulate at the base of the steel pipe column over many years of use.
In particular, in the case of having vertical ribs, there was a problem that cracks based on fatigue occurred at the upper end welds (position 2a shown in FIG. 2) of the vertical ribs, and in some cases, the steel pipe columns collapsed due to fracture. . This is because when a lateral load is applied to the steel pipe column, the stress generated thereby concentrates on the welded portion 2a at the upper end, and the welded portion 2a, which is the fillet weld toe at the upper end of the vertical rib, becomes the stress concentrated portion 3 This is because it will be accompanied.
[0008]
Moreover, even in the case of a simple structure not provided with vertical ribs, similarly, there is a problem that a crack based on fatigue occurs at the base portion of the steel pipe column, and in some cases, the steel tube column collapses and collapses.
The present invention prevents the steel pipe column from collapsing even when a crack occurs and breaks as described above, and it is necessary to urgently provide lighting, signs, etc. for a period until repair. An object of the present invention is to provide a steel pipe column base structure which is held in position and can maintain the function of the steel pipe column.
[0009]
The present invention is a steel pipe column base structure that constitutes the base of a steel pipe column to be erected, and the steel pipe column and the base plate and the rib are welded to each other so as not to collapse at the base. outer diameter, the range der of 0.9 to 0.98 times the inner diameter of the lowermost end of the tubular columns is, at a length of more than the height of the ribs, bars jamming when the steel column becomes collapsed likely state at the base an inner intubation preparative ing solved the above problems by tubular columns the base structure, characterized in that the encapsulated fixed to the steel column by a fixing means as the inner surface of the steel column and the the inner intubation is not in contact .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described with reference to FIG. Note that the same members already described in FIG. 2 are denoted by the same reference numerals and description thereof is omitted here.
Fig.1 (a) is a fragmentary sectional view of the steel pipe pillar base structure of this invention, and has shown the left half of the figure as sectional drawing. Moreover, FIG.1 (b) is the AA view top view which cut | disconnected and showed the AA part of Fig.1 (a).
[0011]
The present invention is characterized in that an inner intubation tube 10 is included in the vicinity of the lower end portion of the steel pipe column 1. That is, the steel pipe column base structure of the present invention includes at least the steel pipe column 1 and the inner tube 10 included in the vicinity of the lower end portion of the steel pipe column 1.
In the base near the lower end of the steel pipe column 1, fatigue failure occurs due to external forces repeatedly applied in the lateral direction. The inserted intubation tube 10 serves as a support rod, and competes with the upper and lower inner surfaces of the fractured portion of the steel tube column 1 to prevent the broken upper portion of the steel tube column from collapsing completely.
[0012]
It is necessary to immediately repair and replace the steel pipe column in such a state, but during the preparation, it is possible to reliably prevent the collapse of the steel pipe column, so that damage to surrounding facilities and The function as an illumination pillar, a sign pillar, etc. can be maintained urgently without leading to traffic obstruction.
Here, the inner tube 10 is preferably connected to the steel pipe column 1 with a bolt 7. Although FIG. 1 shows an example in which the inner tube 10 and the steel pipe column 1 are connected by two bolts 7, they may be connected by about one or two. This bolt 7 is used to connect and hold the inner intubation tube 10 inside the steel pipe column 1 during transportation until installation, and after installation, the inner intubation tube vibrates in the steel pipe column and damages the inner surface. In order to prevent this, it is fixed. Therefore, no particular strength is required. If there is no particular problem, the inner intubation may be simply enclosed within the steel pipe column without being bolted.
[0013]
The steel pipe column is generally a tapered pipe, but a straight pipe is usually used as an intubation. The outer diameter of the inner tube is preferably about 0.9d to 0.98d, where d is the inner diameter of the lowermost end of the steel pipe column. If the outer diameter of the inner tube is less than 0.9 d, the competition between the outer circumferential surface of the inner tube and the upper and lower inner circumferential surfaces of the broken portion of the steel tube column when the fracture position of the steel tube column is relatively low May not work well and may not prevent collapse. On the other hand, using an inner tube having a large outer diameter exceeding 0.98d is not preferable because the inner surface of the steel tube column and the inner tube are always in contact with each other due to vibration of the steel tube column, and the inner surface of the steel tube column is easily damaged.
[0014]
On the other hand, the length of the intubation is preferably about 3d to 10d.
If the length of the intubation is less than 3d, there is a possibility that the tube may come off and collapse when a tear occurs in the vicinity of the base portion of the steel pipe column. Moreover, even if an intubation with a length exceeding 10d is included, the effect of preventing collapse does not change, so that it is not unnecessarily lengthened from the viewpoint of cost.
[0015]
In addition, in FIG. 1, although it has shown about the structure which has a vertical rib in the base of a steel pipe column, this invention is not limited to this, A vertical rib is unnecessary and the simple which joined the steel pipe column directly to the base plate The same applies to the base structure. Moreover, also in the steel pipe column 1 supported by the flange 11 via the mount 13 on the wall 12 as shown in FIG. 3, the same effect can be acquired by providing the bottom plate in the steel pipe column and enclosing the inner tube 10. it can.
[0016]
Furthermore, the present invention can also be applied to a method of directly embedding and fixing the lower portion of the steel pipe column in a base portion such as the ground without using a base plate.
[0017]
【The invention's effect】
According to the present invention, even when the steel pipe column is broken and broken at the base portion of the steel pipe column, the steel pipe column is not immediately collapsed, and the steel pipe column can be held in an emergency manner. As a result, it is possible to eliminate troubles such as damage to peripheral equipment caused by collapse of steel pipe columns and troubles in traffic, and it is possible to hold equipment such as lighting and signs in place as soon as possible until repair. It has become possible.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an example of a steel pipe column base structure according to the present invention.
FIG. 2 is a schematic view showing an example of a conventional steel pipe column base structure.
FIG. 3 is a schematic view showing an example of a steel pipe column base structure according to the present invention.
[Explanation of symbols]
1 Steel pipe column
2a, 2b Welded part 3 Stress concentrated part 4 Vertical rib 5 Base plate 6 Anchor mounting hole 7 Bolt
10 Intubation (reinforcing tube)
11 Flange
12 walls
13 frame
14 Fastener

Claims (1)

A steel pipe column base structure that constitutes the base of a steel pipe column to be erected , wherein the outer diameter is in the base of the steel pipe column so that the steel pipe column and the base plate and the rib are welded to prevent collapse at the base. Ri 0.9 to 0.98 times the der the lowermost end of the inner diameter of the tubular columns, with a length of more than the height of the rib, among ing and jamming rod when said tubular columns became collapsed likely state at the base A steel pipe column base structure comprising: an intubation tube which is fixed and contained in the steel tube column by a fixing means so that the inner surface of the steel tube column does not contact the inner tube.

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