JPH07158015A - Steel pipe lap joint structure of steel pipe/concrete composite structure columnar body - Google Patents

Abstract

PURPOSE:To enable a steel pipe to be added efficiently through a simple work and to construct a columnar body of sufficient strength as well in constructing a steel pipe/concrete composite structure columnar body. CONSTITUTION:With regard to a columnar body constructed by successively adding steel pipes upwards on the one erected on a foundation and placing concrete 5, 6, 7 so as to envelop the steel pipes 1, 2 therein, the two steel pipes 1, 2 added to the top and the bottom are arranged on approximately the identical axis and the outer circumference of the joint portion is arranged with a short joint steel pipe 3 of an inside diameter larger than the outside diameter of the said both steel pipes on approximately the identical axis covering both steel pipes. The outside circumference surface of both steel pipes 1, 2 ends enveloped by the joint steel pipe 3 has ribs 1a, 2a protruded beyond them and the space between the outside circumference of both steel pipes 1, 2 ends and the inner circumference of the joint steel pipe 3 is filled with concrete 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a columnar body such as a high bridge pier of a steel pipe / concrete composite structure classified into SRC construction (steel frame reinforced concrete construction), and particularly to a lap joint of steel pipes contained in the concrete columnar body. Regarding the structure.

[0002]

2. Description of the Related Art Is it possible to construct bridges with high piers such as highways in mountainous areas more efficiently? The steel pipe / concrete composite structure high pier, which is the subject of the present invention, has been devised to meet such a demand. Conventionally, conventional piers are RC structures (reinforced concrete structures), whereas the recently developed steel pipe / concrete composite structures are classified as SRC structures.

In RC piers, concrete is placed by arranging strips at a constant pitch on a large number of longitudinal main bars. Like a highway in the mountains, the height of the pier exceeds 30 m and 100
If it reaches m, a huge amount of labor and temporary construction are required for the reinforcement work, formwork work and concrete work.

On the other hand, in the steel pipe / concrete composite structure, steel pipes are used in the vertical direction and PC strands are used in the horizontal direction instead of the reinforcing bars. Moreover, the concrete construction is done by the slip-form method. That is, steel pipes erected on the foundation are successively added upward, and a slipform formwork / scaffold is hung on the steel pipes, and concrete is poured while spirally winding PC strands as strips around the steel pipe. It is expected that such a new method will dramatically improve the construction speed.

[0005]

According to the previously proposed technique relating to the steel pipe / concrete composite structure high pier described above, 30
As a method of adding steel pipes over a height of up to 100 m, the ends of the steel pipes are butted and joined by welding or bolting. However, in the method of joining steel pipes by welding and bolting, welding work or bolting work on site is relatively troublesome, especially because the relationship with the progress of other works is complicated and the critical path in the construction period. I found out that

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to efficiently add steel pipes by a simple construction in constructing the above-mentioned steel pipe / concrete composite structure columnar body. Further, the present invention provides a lap joint structure of a steel pipe capable of constructing a columnar body having sufficient strength.

[0007]

A lap joint structure for steel pipes according to the present invention is constructed by sequentially adding steel pipes erected on a foundation upward and placing concrete to enclose the steel pipes. In the columnar body, the upper and lower steel pipes that have been added are arranged on substantially the same axis, and
In the outer peripheral portion of the joint portion, a short joint steel pipe having an inner diameter larger than the outer diameters of the both steel pipes is arranged substantially coaxially over both steel pipes, and the outer peripheral surface of the end portion of the both steel pipes enclosed in the joint steel pipe is Ribs are provided to project, and concrete is filled in a space between the outer circumferences of the end portions of the both steel pipes and the inner circumference of the joint steel pipe.

[0008]

The stress is transmitted between the steel pipes through the adhesive force between the concrete filled in the gap and the steel pipe with both ribs and the adhesive force between the concrete and the joint steel pipe.

[0009]

FIG. 1 shows an embodiment of a lap joint structure for steel pipes in a steel pipe / concrete composite structure columnar body adopting the present invention. As shown in the figure, the steel pipe 2 having the same diameter is added to the upper end of the lower steel pipe 1 on the same axis, but a joint steel pipe 3 having a larger diameter than both steel pipes 1 and 2 is interposed on the outer periphery of the joint portion. ing. The length of the joint steel pipe 3 is about 2 to 4 times the diameter of the steel pipes 1 and 2, the upper end of the steel pipe 1 is inserted to the middle part of the joint steel pipe 3, and the lower end of the steel pipe 2 is inserted to the middle part of the joint steel pipe 3. In this case, the joint steel pipe 3 is selected in such a dimensional relationship that an appropriate space is provided between the inner surface of the joint steel pipe 3 and the outer surfaces of the steel pipe 1 and the steel pipe 2.

Four positioning brackets 4 are pre-welded to the outer circumferences near the ends of the steel pipes 1 and 2 so that the steel pipes 1 and 2 and the joint steel pipe 3 are combined in the above-mentioned arrangement relationship. As shown in FIG. 2, the four positioning brackets 4 are radially attached at equal intervals. The upper end of the lower steel pipe 1 is assembled so as to cover the joint steel pipe 3, and the lower end edge thereof is brought into contact with the bracket 4. Further, the lower end of the upper steel pipe 2 is inserted into the joint steel pipe 3, and the bracket 4 of the steel pipe 2 is brought into contact with the upper end edge of the joint steel pipe 3. Then, the three parties are combined in the above-described predetermined arrangement relationship. Instead of providing the bracket 4 on the steel pipe 2, a plurality of spacers may be installed on the top end of the steel pipe 1 and the steel pipe 2 may be erected coaxially on the spacers.

Further, as shown in FIG. 1, a large number of outer ribs 1a are provided on the outer peripheral surface of the end of the steel pipe 1, and
Exactly similarly, a large number of outer ribs 2a are provided on the outer peripheral surface of the end portion of the steel pipe 2 in a protruding manner. Further, a large number of inner ribs 3a are provided on the inner peripheral surface of the joint steel pipe 3 so as to project therefrom. Steel pipe 1, 2
The outer ribs 1a, 2a of the above and the inner rib 3a of the joint steel pipe 3 face each other at their overlapping portions. In this embodiment, concrete 5 is filled inside both steel pipes 1 and 2, and concrete 6 is filled in a space between the inner circumference of the joint steel pipe 3 and the outer circumferences of both steel pipes 1 and 2, and further the steel pipes are filled. Concrete 7 is placed so as to entirely enclose 1 and 2 and the joint steel pipe 3. As described above, the concrete strand 7 is placed after spirally winding the PC strand as the stirrup around the erected steel pipe, but the PC strand is omitted in this figure.

In the overlapping portion of the steel pipes 1 and 2 and the joint steel pipe 3, the steel pipe 1 has an outer rib 1a, the steel pipe 2 has an outer rib 2a, and the joint steel pipe 3 has an inner rib 3a. Filled concrete 3
The adhesive force between the steel pipe 1, the steel pipe 2, and the joint steel pipe 3 becomes sufficiently large. Therefore, the stress is transmitted between the steel pipes 1 and 2 through the concrete 6 and the joint steel pipe 3.

In this embodiment, the inside of the steel pipe is also filled with concrete. In this case, however, the effect of restraining the thinning or shifting of the steel pipe due to the Poisson's ratio can be expected.
This is a more desirable embodiment. However, depending on the case, the columnar body may be constructed in a hollow state without filling concrete inside the steel pipe. It is economical to fill the inside of the steel pipe with concrete because the lap joint length can be shortened. Although the outer ribs 1a and 2a are formed only on the tip portions of the steel pipes 1 and 2 in the figure, it goes without saying that the outer ribs may be formed over the entire length.

Another embodiment of the present invention is shown in FIG. In the embodiment of FIG. 3 (A), a large number of deformed rebars 8 are provided in the space between the inner circumference of the joint steel pipe 3 and the outer circumferences of the steel pipes 1 and 2.
Are appropriately arranged to fill the concrete 6. Figure 3
In the example of (B), a large number of ribbed steel plates 9 are radially arranged in the space between the inner circumference of the joint steel pipe 3 and the outer circumferences of the steel pipes 1 and 2 to fill the concrete 6. Figure 3
In the example of (C), a large number of ribbed steel plates 10 are tangentially arranged in the space between the inner circumference of the joint steel pipe 3 and the outer circumferences of the steel pipes 1 and 2 to fill the concrete 6. The deformed bar 8, the ribbed steel plate 9, and the ribbed steel plate 10 in these three examples all contribute to the stress transmission between the steel pipes 1 and 2, and enhance the mechanical coupling force between the steel pipes 1 and 2. In addition, in the three examples, the joint steel pipe 3 may be the one without the above-mentioned inner rib 3a.

[0015]

As described in detail above, according to the present invention, a short joint steel pipe having a large diameter is arranged on the outer periphery of the joint portion of two steel pipes having outer ribs on the outer peripheral surfaces of the end portions. The space between the inner circumference and the outer circumference of the two steel pipes is filled with concrete to create a lap joint structure that transmits the stress between the steel pipes, so the construction of the above-mentioned steel pipe / concrete composite structure columnar body is simple and rational. Therefore, it is possible to construct a columnar body that can be effectively manufactured and has sufficient mechanical strength.

[Brief description of drawings]

FIG. 1 is a schematic view of a lap joint structure for a steel pipe according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement state of a positioning bracket in FIG.

FIG. 3 is a plan sectional view showing a main part of another three embodiments of the present invention.

[Explanation of symbols]

 1 steel pipe 1a outer rib 2 steel pipe 2a outer rib 3 joint steel pipe 3a inner rib 4 positioning bracket 5,6,7 concrete 8 deformed rebar 9 ribbed steel plate 10 ribbed steel plate

Claims (4)

[Claims] 1. In a columnar body constructed by sequentially adding steel pipes erected on a foundation in an upward direction and placing concrete so as to enclose the steel pipes, the two steel pipes above and below the pipes added together are almost A joint steel pipe having a short inner diameter larger than the outer diameters of the both steel pipes is arranged substantially coaxially on the outer peripheral portion of the joint portion while being arranged on the same axis, and the joint steel pipes of the both steel pipes are included in the joint steel pipes. Ribs are projected on the outer peripheral surface of the end of the steel pipe, concrete is filled in the gap between the outer periphery of the ends of both steel pipes and the inner periphery of the joint steel pipe. Lap joint structure of steel pipes in concrete composite structure columns. 2. The steel pipe according to claim 1, wherein ribs project from the inner peripheral surface of the joint steel pipe.
Lap joint structure in concrete composite structure columns. 3. The steel pipe / concrete composite structure columnar body according to claim 1, wherein deformed rebars are arranged in a gap between the outer circumferences of the end portions of the both steel pipes and the inner circumference of the joint steel pipe. Lap joint structure in. 4. The steel pipe / concrete composite structure columnar column according to claim 1, wherein a steel plate with ribs is arranged in a space between an outer circumference of an end portion of both steel pipes and an inner circumference of the joint steel pipe. Lap joint structure in the body.