JPS62160337A - Unbond filled steel pipe structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an unbonded filled steel pipe structure used for columns, piles, etc.

``Prior art'' This type of structure is known as the filled steel pipe concrete structure, or the conventional filled steel pipe concrete structure consists of vertically erecting a simple straight cylindrical steel pipe that also serves as a formwork. The pipe is simply filled with concrete, and the steel pipe and concrete are in a state of additional pouring, and mechanically behave as one.

``Problems to be solved by the invention'' However, in conventional pipes, when compressive force in the axial direction is applied, the steel pipe and concrete are distorted as a unit, and when the jlRI pipe is severely distorted, the von Mises yield condition is not met. If it exceeds the limit, it may cause buckling of the station IM.

Therefore, the increased axial stress causes the copper I pipe to reach a considerable stress level, and the confining effect cannot be fully exerted, resulting in a column or pile with a larger cross-section than necessary.

The present invention was made in view of the above problem, and by making full use of the confining effect of steel pipes, the compressive strength is significantly improved, and the cross-sectional area of columns and piles can be made smaller than that of the conventional method. The object of the present invention is to provide an unbonded filled steel pipe +14 structure that can resist the tensile load caused by the overturning moment of the entire structure during an earthquake.

"Means for Solving the Problems" In order to solve the above-mentioned problems, the present invention provides a ring-shaped gap that edges the steel pipe in the axial direction in at least a part of the steel pipe in the axial direction. A cylindrical body that covers the ring-shaped gap from the inside and whose outer circumferential surface is slidable on the inner circumferential surface of the front three steel pipes is provided inside, and one end of this cylindrical body is connected to one of the steel pipes having the edge cut. At the same time, a support plate is provided in a part of the cylindrical body to press the structural filler filled in the steel pipe, and the cylindrical body is provided with a bearing plate that presses the structural filler filled in the steel pipe, and A connector is provided to connect the steel pipes to each other, and a structural filler such as concrete is filled inside the steel pipe, and at the boundary between the steel pipe and the structural filler described in 11, the steel pipe and the structural filler are filled. It is characterized by the provision of an unbonding treatment layer to eliminate adhesion.

"Example" Hereinafter, the present invention will be described in detail with reference to the drawings. 1 and 2 show a first embodiment of the present invention, and FIG. 1 shows a column of unbonded filled steel pipe structure (hereinafter simply "
This is a diagram showing how several floors of pillars (abbreviated as "pillars") are connected to H, and Figure 2 is an enlarged view of the part shown by arrow A in Figure 1. be.

In these figures, the symbol l is a steel pipe, and 2 is a steel pipe l.
Inside is said concrete.

At predetermined locations in the axial direction of the steel pipe 1 (in this example, one location per three floors), there are holes for transmitting the axial force applied to the steel pipe 1 from the steel pipe 1 to the concrete inside. An axial force transmitting section 3 is provided. The axial force transmission section 3 includes a ring-shaped gap 4 that edges the steel pipe 1 in the axial direction, a cylindrical body 5 provided in the ring-shaped gap 4, and a bearing plate 6 fixed to the cylindrical body 5. It consists of a connector 7 provided on a steel pipe 1 divided into upper and lower parts by a ring-shaped gap 4,
It is provided approximately in the middle between the floors (the point of reversal of the bending moment applied to the column H).

The cylindrical body 5 is provided between the ring-shaped gap 4, and
A ring-shaped jI+1 pipe 5a whose upper end is fixed to the lower end of the upper steel pipe 1 by welding, one end fixed to the inner peripheral surface of this ring-shaped steel pipe 5a, and the other end slidably with the lower steel pipe 1. It consists of fitted cylindrical steel pipes 5b. It should be noted that between the cylindrical steel pipe 5b and the steel pipe 1 fitted therein, there is a friction reduction (o
For example, tetrafluoroethylene resin, etc.) 8 is provided,
A flexible material (rubber, styrofoam, clay, etc.) 8a is attached to one end of the cylindrical steel pipe 51). In addition, the bearing plate 6
is a circular plate with a hole 6a formed inside, and a cylindrical steel pipe 5b
It is fixed almost horizontally to the lower end of the steel pipe 1, and is enclosed in the concrete 2 inside the steel pipe 1. Note that whether or not to form the holes 6a in the bearing pressure plate 6 is free. The connecting device 7 includes a flange 9 welded and fixed to the lower end of the upper steel pipe l divided by the ring-shaped gap 4, and a flange 9 fixed to the lower end of the upper steel pipe l divided by the ring-shaped gap 4.
A flange IO welded and fixed to the upper end, and a port 11°I that connects these flange 9 and flange IO to each other.
The upper surface of the flange 9 has ribs 9a, 9a fixed to the flange 9 at the bottom and to the steel pipe 1 at the sides.

..., and the lower surface of the flange 10 has ribs 10a and loa fixed to the upper part to the Franz lO and the side part to the copper I pipe l.
,... are provided.

In addition, on the inner surface of the steel pipe l constructed as described above, ji
Separation (4 (enhonto treatment layer) 12 to eliminate adhesion between lJ pipe I and filling concrete is applied in advance, and then concrete 2 is placed and filled inside the steel pipe l.As separation material 12 are paraffin, asphalt,
A lianhon treatment layer is formed by applying oil, grease, vaseline, etc. to the inner surface of the tube.

Next, describing an example of construction of such Htt, the following methods can be considered as methods for providing the axial force transmitting portion 3 on the steel pipe l.

(1) First, in a factory, a cylindrical steel pipe 5b is welded to the inside of the ring-shaped steel pipe 5a, a bearing plate 6 is fixed to the lower end of the cylindrical steel pipe 5b, a flexible material is fixed to one end of the cylindrical steel pipe 5b, and the ring-shaped steel pipe 5a is
A flange 9 and a rib 9. The axial force transmitting part 3 is manufactured by welding l. Further, the axial force transmitting portion 3 is welded to the tip of the upper steel pipe I at a portion 13 in FIG. 2 at a factory. Next, at the site, the steel pipe 1 is built into the lower steel pipe 1 to which the flange 10 and the rib IOa are welded to the upper end so that a predetermined ring-shaped gap 4 is formed, and the flange 9 and the flange IOa are welded together. Attach the bolt 11 and nut Ila between them. In this case, a spacer (not shown) may be inserted into the ring-shaped gap 4 to hold it, or a double nut (not shown) may be provided on each side of the flanges 9 and 10. It's good.

Finally, a method of pouring concrete 2 into the steel pipe 1 and removing the spacer or canceling the double NAND after the concrete 2 has hardened.

(2) First, the axial force transmission section 3 is manufactured in a factory in the same manner as in (1). Next, at the site, the axial force transmitting part 3 is installed so that a predetermined ring-shaped gap 4 is formed on the upper part of the lower steel pipe 1 to which the flange [0 and the rib IOa are welded to the upper end. A bolt 11 and a nut Ila are installed between the two and Franz 10. that time,
The ring-shaped gap 4 is maintained in the same manner as in the case (1) above. Next, after welding the section 13 of the steel pipe 1 to the upper part of the steel pipe 1, concrete 2 is poured into the steel pipe 1. How to release it.

Note that it is also possible to first pour concrete into the lower steel pipe to a predetermined position, then install the axial force transmission section 3 on top of it, erect the upper steel pipe, and then pour concrete onto the upper steel pipe. good. Further, as the pillars I② are successively constructed upward, the concrete 1-2 is compressed and the steel pipe 1 is shifted downward and the ring-shaped gap 4 becomes narrower. By tightening the nut Ila on the outside of the IO, the bolt 11 is connected and the upper and lower steel pipes are given rigidity and resistance against tension in the axial direction.

Next, the filtering effect in the above-mentioned filled steel pipe concrete structure will be explained.

First, the shearing force applied to the beams K 1 , K 2 , and K for three floors is transmitted to the steel pipe l where they are welded.

However, the steel pipe 1 and the concrete 2 inside are separated by an unbonding treatment layer 12, and the steel pipe 1 is mechanically divided by ring-shaped gaps 4 provided every three floors, and the axial direction caused by compression Since the shearing force is not transmitted to the steel pipe I below, the shearing force transmitted to the steel pipe I is not directly transmitted to the concrete 2 inside, and the shaft received at the lower end of the steel pipe I is The force is transmitted to the concrete 2 below via the bearing plate 6 of the force transmission section 3.

Next, when the axial force is transmitted to the concrete 2 below, the concrete 2 is compressed, and when the compressed strength exceeds a predetermined strength, distortion occurs in the axial direction. Accordingly, the steel pipe 1B shifts downward, but there is a ring-shaped gap 4 in the axial force transmission section 3.
is formed, the upper steel pipe 1 does not come into contact with the lower steel pipe 1, and reliably transmits the shearing force from the steel pipes K, K, and K to the concrete 2 (here, the ring-shaped gap 4 is The upper steel pipe 17'J is dimensioned so that it does not come into contact with the lower steel pipe 1 even if it moves). Further, the concrete 2 below is distorted in the axial direction and sharply transversely distorted in the radial direction. However, the steel pipe below! As with the steel pipe l above, the steel pipe l bears only the load of three floors.
The axial stress generated in this case is small. Especially 1. In this case, the steel pipe I is in an unbonded state with the filling concrete 2, and the steel pipe I is not restrained by the concrete at all in the axial direction. Therefore, although axial strain occurs in the concrete 2, almost no axial strain occurs in the steel pipe I. These effects also occur between the upper steel pipe 1 and the internal concrete 2.

Therefore, if the Mises yield condition is applied, the conofinding effect of the steel pipe 1 due to the circumferential stress can be fully exerted, and as a result, the compression? It is possible to improve the strength against 1η weight, and it is possible to reduce the cross-sectional area of i I-1.

Furthermore, short-term loads such as earthquakes act on this column I, and
When a tensile force due to a moment acts on l, the upper and lower steel pipes are connected by the connector 7, so they have rigidity and proof strength against the tensile force, and the steel pipe 1 and concrete 2 behave as one.

Next, a second embodiment of the present invention will be described using FIG. FIG. 3 is an enlarged view of the portion indicated by arrow A in FIG. In the figures, the same components as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In this second embodiment, the axial force transmitting section 3 in the first embodiment is configured as follows. The cylindrical body 5 has a ring-shaped steel pipe 5a whose lower end is fixed by welding to the upper end of the lower steel pipe l, one end is fixed to the inner peripheral surface of this ring pipe 5a, and the other end is fixed to the upper end of the lower steel pipe l. It consists of a steel pipe 1 and a cylindrical steel pipe 5b slidably fitted together. Further, a bearing plate 6 is fixed to the upper part of the cylindrical body 5, and a cylindrical steel pipe 5
A low friction material 8 is inserted between b and the steel pipe l fitted therein, and a flexible material 8a is attached to the upper end. The other configurations are the same as in the first embodiment.

Therefore, in this embodiment, the shearing force applied to the three floors of the steel pipes 1, 2, and 3 acts as a tensile force on the steel pipe 1 where they are welded, and furthermore, is transmitted to the internal concrete 2 via the first
It is possible to obtain the same effect as in the embodiment, and it is even more advantageous with respect to the Mises yield condition and local buckling.

In the above embodiment, the steel pipe 1 was filled with concrete, but mortar, hydraulic material of the pond, soil, sand, metal powder, glass powder, plastic, clay, etc. If so, a structural filler having sufficient compressive strength may be used instead. Furthermore, it is optional to increase the strength of the concrete by inserting reinforcing bars into the concrete or arranging prestressed steel materials.

"Effects of the Invention" As explained above, the present invention provides an axial force transmitting section that transmits the axial force applied to the steel pipe to the concrete in the steel pipe at a predetermined location, and further connects the upper and lower steel pipes with a connector. Therefore, only a small axial stress below a certain value is generated in the steel pipe. Therefore, by applying the Mises yield condition, the confining effect of the steel pipe due to the circumferential stress can be fully exhibited.As a result, the strength against compressive loads can be significantly improved, and the cross-sectional area of the column can be Furthermore, if a short-term load such as an earthquake is applied to this column and a tensile force due to a moment is applied to the column,
Since the upper and lower steel pipes are connected by a connector, they have rigidity and resistance against tensile force, and the steel pipes and concrete behave as one.

[Brief explanation of drawings]

1 and 2 show the first embodiment of the present invention, so FIG. 1 is a partially sectional side view showing the entire embodiment, and FIG. 2 is a partially sectional side view of the embodiment. FIG. 3 is an enlarged sectional view of the main part (arrow A section in FIG. 1) showing the second embodiment,
FIG. 2 is an enlarged cross-sectional view of a portion viewed from arrow A in FIG. 1; 1... Steel pipe, 2... Concrete, 3...
... Axial force transmission part, 4 - Ring-shaped gap, 5 ... Cylindrical body, 6 ... Bearing plate, 7 ... Connection tool, 12 ...
... Separation material (unbond processing layer).

Claims (1)

[Claims] In a filled steel pipe structure used as a column or pile, a ring-shaped gap is provided in at least a part of the steel pipe in the axial direction to edge the steel pipe in the axial direction, and the ring-shaped gap is covered from the inside of the steel pipe, and A cylindrical body whose outer circumferential surface is slidable on the inner circumferential surface of the steel pipe is provided, one end of this cylindrical body is fixed to one of the edge-cut steel pipes by attaching a flexible material, and the cylindrical body is A bearing plate is provided in a part of the steel pipe to press the structural filler filled in the steel pipe, and a connecting device is provided to connect the steel pipes that are edged in the axial direction by the ring-shaped gap, and furthermore, a bearing plate is provided inside the steel pipe to press the structural filler filled in the steel pipe. In addition to filling the steel pipe with a structural filler such as the above, an unbonding treatment layer is provided at the interface between the steel pipe and the structural filler to prevent adhesion between the steel pipe and the filled structural filler. Unbonded filled steel tube structure.