KR100720730B1 - Concrete filled composite double tube and method connecting the tube with the other - Google Patents

Abstract

The CFCT structure of the present invention is a structure in which the weight of itself is reduced while increasing the bearing capacity for the bending moment and the shear force.

Ii) In addition, the factory can be manufactured and assembled.

Iii) It is suitable to be used as cross member to support bending moment and shear force.

Iii) It is a structure in which steel pipe and concrete behave in one piece.

The construction of CFCT structure for this purpose is to place two inner and outer steel pipes of circular and regular polygon in the center of coaxial, and to fill high strength concrete between two steel pipes, and fix the inner and outer steel pipes with fastening bolts, and the outer circumferential surface of the inner steel pipes. Stud bolts are installed on both ends, and connecting flanges are provided on both ends of the inner and outer steel tubes in the longitudinal direction.

Double composite tube, CFCT structure, internal and external steel pipe, fastening bolt, stud bolt

Description

Concrete filled composite double tube and method connecting the tube with the other}

1 is a perspective view of a double composite tube structure filled with the present invention high strength concrete

2A is a cross-sectional view of FIG.

2B enlarged view of portion C of FIG. 2A

3 is an exploded perspective view of the junction of FIG.

4A is a cross-sectional view taken along line B-B in FIG.

Figure 4b another embodiment of Figure 4a

5 is a state diagram in which the diaphragm is installed in the double composite tube structure filled with the present invention high-strength concrete

* Brief Description of Drawings

100; CFCT construct, 10; Inner steel pipe, 12; Stud bolts, 16; Connecting flange, 17; Bolt hole, 18; Reinforcement, 19a; Fixing bolt, 19b; Fixing nut, 20; Outer steel pipe, 30; Fastening adjustment bolt, 40; High strength concrete, 50; Sealing member 52; Inlet, 54; Welding, 60; Sleeve, 70; My diaphragm

The present invention relates to a composite filled composite double tube (CFCT) structure filled with high-strength concrete and a method of manufacturing the same.

The double composite tube filled with high-strength concrete is suitable for use as a structural member subjected to bending moment and shear force as well as a compressive member subjected to axial load.

The composite tube is made of steel, and its shape is pipe.

The double beams filled with high-strength concrete can be applied to the cast beam of bridge, long span structure of large indoor gymnasium, `` beam + column '' integrated structure of large hangar, steel pipe pole for distribution, pillar of skyscraper, etc. to be.

The prior art has a structure in which the outer circumferential surface is surrounded by a steel plate and the inside thereof is filled with concrete only, which is called a conventional CFT (concrete filled tube) structure.

The history of the existing CFT structure is long. It was first used in the piers of British railway bridges in 1879.

Since then, Japan has established structural design standards for steel pipe concrete in 1967 and applied them to various civil structures, including transmission towers.

In 1961 in the United States and in 1995 in Europe, design guidelines for existing CFT structures were completed.

As such, the existing CFT structure is a technology that is widely spread and used.

Although widely prevalent, its application is extremely limited.

More specifically, the structure of the existing CFT has been studied for most columns and is still limited to the research on this.

It is only constructed for columns in field applications.

Research and application of girders, structural materials supporting bending moments and shear forces, can be said to be limited in part.

It is limited to only a few parts, but it is almost the same situation.

Recently, in Korea, the existing CFT structure has been applied to pillars, although they are insignificant.

In this respect, engineering firms and design offices have been actively reviewed.

Existing CFT structure is the outer circumference is surrounded by steel plate and the inside is filled with concrete.

The steel plate has only a flat surface of the steel plate, and since there is no structural device at all, it is a structure that simply surrounds concrete only with the surface of the steel plate.

If there is no steel pipe on the outer circumference, cracks occur on the outer circumference of the concrete during the celebration, and as a result peeling phenomenon occurs on the concrete.

Even in the existing CFT structure, peeling of steel pipes and concrete occurs.

However, due to the restraint force of the steel pipe it causes only a small amount of peeling phenomenon.

The reason why peeling of steel pipe and concrete occurs is the existing CFT structure.

In the existing CFT structure, the steel pipe simply surrounds the concrete, and there is no action to integrate the steel pipe and concrete, so the steel pipe and the concrete are independent of each other.

As such, when the steel pipe and the concrete are congratulated in a state independent of each other, there is a problem that the crack of the concrete is inevitable because the steel pipe and the concrete behave independently of each other.

If steel pipe and concrete are integrated and behave, the crack of concrete is prevented by mutual reinforcing action of steel pipe and concrete.

Existing CFT structure is filled with concrete inside the steel pipe, so its own weight is large, it is advantageous for the celebration, but there is a problem that can not be used as a structural material receiving the bending moment and shear force.

If the weight is large, there is a problem that it is difficult to use as a cross member of the beam or gymnasium roof which is a structural member subjected to bending moment and shear force.

In particular, the horizontal material, etc. should be a prefabricated structure, but its own weight is not suitable to make a prefabricated structure.

In addition, the relationship with the diaphragm 70, which is a structural reinforcing plate, will be described.

Since flexural strength and shear strength are given by the member cross-section, structural reinforcement is more advantageous in structural mechanics than installing the diaphragm 70 inside the member.

However, a conventional external diaphragm is used at the junction of the existing CFT column and beam.

This is because the structure and shape of the inner diaphragm 70 can be used.

If the inner diaphragm 70 is used, there is a fear that voids are generated during concrete filling.

If voids are generated in the existing CFT structure, the bending moment, shear force, and bearing capacity during axial weakening are not only reduced, but also cause problems in the structural stability of the existing CFT structure.

The present invention is a concrete filled composite double tube (CFCT) structure filled with high-strength concrete that solves the problems of the existing CFT structure.

An object of the present invention is to form a double composite steel pipe tube and to fill the concrete in the double composite steel tube tube so that the double composite steel tube tube and the concrete composite behavior, another object is a double composite steel tube tube and concrete filled therebetween In order to make the CFCT structure lighter by integrally synthesizing it, another object is to make the assembly as well as the factory production, and to be able to use it as a cross member supporting the bending moment and the shear force by enabling the assembly. There is another purpose.

The CFCT structure of the present invention is a structure in which the weight of itself is reduced while increasing the bearing capacity for the bending moment and the shear force.

Ii) In addition, the factory can be manufactured and assembled.

Iii) It is suitable to be used as cross member to support bending moment and shear force.

Iii) It is a structure in which steel pipe and concrete behave in one piece.

In order to achieve the structure of ⅰ), two large and small inner and outer steel pipes should be positioned at the center of coaxial and the high strength concrete is filled between the two steel pipes (see Fig. 2a).

The double composite tube filled with high-strength concrete has a higher allowable flexural strength and shear strength than the existing CFT structure and is light in weight.

This is because the cross-sectional coefficient and yield strength of the steel pipe are increased in a plurality of cross sections (t1 + t2 = 2t) than the single cross section t1 when the double steel pipe is integrally viewed.

Coaxial is used here to express that a certain distance is maintained between the outer tube and the inner tube.

In other words, placing two steel pipes in the center of coaxial means that the gap between inner and outer pipes is the same.

In other words, once the cross-sectional shape of the outer steel pipe is given, the cross-sectional shape of the inner steel pipe automatically becomes the same as that of the outer steel pipe.

This is because the distance between the inside and the outside must be the same.

The center of the coaxial does not necessarily have to be a circular cross section.

As long as the distance between an inner side and an outer side can be kept the same, it does not depend on the cross-sectional shape.

As well as a circular cross section, as well as regular polygon cross sections, any polygonal cross section is possible (see Figs. 4A and 4B).

The spacing d between the two steel pipes located at the center of the coaxial is preferably about 1 / 8-1 / 7 of the diameter D of the outer steel pipe.

For example, when the cross-sectional shape is a circular cross section, the interval d between the two steel pipes is preferably about 1 / 8-1 / 7 of the diameter of the outer steel pipe D.

If the spacing d is smaller than 1/8, it is not easy to insert the words of the vibrating trap tube between the two steel pipes.

This is because the spacing d can be smaller than the diameter of the end of the vibratory tract tube, which usually has a diameter of 80 mm.

If the distance d is larger than 1/7, the self weight of the concrete becomes large and becomes a weight body.

If it is weighted, even if it is manufactured as an assembly structure, it is not suitable for use as a cross member supporting bending moment and shear force.

It is because the main technical gist of the present invention is to make a structural member which can be assembled with light weight, but with increased allowable bending strength and shear strength.

In order to achieve the structure of ii), connecting flanges are formed at both ends in the longitudinal direction of the double tube formed of two inner and outer steel pipes, and the structure between the inner and outer steel pipes is sealed with a sealing member. 3)

Injection holes should be formed in the sealing member.

The width of the connecting flange should not deviate from the outer steel pipe, and on the main surface of the connecting flange there is a reinforcing protrusion.

The connection of the connection flange is fixed by high tension bolts.

The outer circumferential surface of the outer steel pipe at the joint flange is integrally welded and joined by the sleeve.

Since the height of the sleeve welded to the outer circumferential surface of the outer steel pipe is almost the same as the height of the outer circumferential surface of the outer steel pipe, it is not easy to visually identify the joint, so the appearance is beautiful.

Even when used as a cross member, the appearance is not inferior.

In order to have the structure of ⅲ), it should be lightweight and easy to assemble.

Since the concrete is filled only in the space formed by the inner and outer steel pipes, the interval between the concrete fillings is preferably 1 / 8-1 / 7 of the coaxial width (D) of the outer steel pipes, thereby reducing the weight.

Connection flanges are formed at both ends of the inner and outer steel pipes in the longitudinal direction, so that they can be assembled.

It is a structure suitable for use as a cross member supporting bending moment and shearing force because it has already made a structure that can be lightweighted and assembled.

In order to achieve the integral behavior structure of ⅳ), there should be a means of integrating steel pipe and concrete.

The means are stud bolts and fastening bolts (see Figs. 4a and 4b). Stud bolts are embedded in concrete while being fixed by welding to the outer circumferential surface of the inner steel pipe.

The length of the stud bolt is almost equal to the gap between the inner and outer steel pipes (only 2-3mm apart).

The gap between inner and outer steel pipes is maintained by stud bolt. However, even if the gap is maintained by the stud bolts, the inner and outer steel pipes should not flow.

If the inner and outer steel pipes are flowed in the process of filling high-strength concrete or hardening, stud bolts are flowed, and high-strength concrete is not filled in place.

This phenomenon not only lowers the compressive strength, but also makes the inner and outer steel pipes and the high strength concrete integrally vulnerable to the integral behavior.

Fastening bolts play two roles.

One is to prevent the inner and outer steel pipes from flowing with each other. (See Figures 4A and 4B)

Fastening bolts are inserted through inner and outer steel pipes.

Since fastening bolts penetrate the inner and outer steel pipes, the flow of inner and outer steel pipes is prevented.

The other is to make the inner and outer steel pipes and high-strength concrete work together integrally.

The inner steel pipe and the high-strength concrete are integrated by stud bolts.

This is because the stud bolts fixed to the inner steel pipe are firmly embedded in the high strength concrete.

However, the outer steel pipe was not integrated with the inner steel pipe nor with the high strength concrete.

However, it is attached only by the adhesive force of concrete.

The adhesive force of concrete alone has a limitation in that the external steel pipe and high-strength concrete behave integrally with respect to the bending moment.

It is this fastening bolt that overcomes these limitations.

In other words, the fastening bolts allow the outer steel pipe, the high-strength concrete, and the inner steel pipe to be integral and behave in one piece.

As the three members act integrally, the resistance to the bending moment and the shear strength are increased.

If the mechanical resistance is the same, the cross section due to the integral behavior may be much smaller than this.

The relationship between the fastening bolts and the internal steel pipe will be described.

If the gap between inner and outer steel pipes is maintained by stud bolts, and the flow of inner and outer steel pipes is prevented by fastening bolts, fastening bolts need not be firmly fixed to inner steel pipes.

This is because the fastening bolt is fixed by the filled concrete in the penetrating state.

In summary, the fastening bolts prevent the inner and outer steel pipes from flowing during the concrete filling process, and after the hardened concrete is cured, the inner and outer steel pipes and the three members of the concrete work together. have.

Fastening bolts and stud bolts are preferably installed symmetrically based on the cross section.

As described above, the CFCT structure of the present invention, unlike the existing CFT structure, allows the internal and external steel pipes and the concrete to be integrated by the fastening fixing bolts and the stud bolts of the internal steel pipes, resulting in the celebration and the external forces such as bending moments and shear forces. It solves the peeling phenomenon which is a problem of the existing CFT structure.

In the CFCT structure of the present invention, since the inner space of the inner steel pipe is empty, not only the existing CFT structure but also the inner diaphragm 70 can be easily installed, and it is easy to appropriately reinforce the working site of stress regardless of the concrete filling site. .

In this regard, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

Two large and small inner and outer steel pipes (10, 20) are located at the center of the coaxial, and between the two inner and outer steel pipes (10, 20) is filled with high-strength concrete and the inner and outer steel pipes with fastening fixing bolts (10 (20) is fixed, but the inner and outer steel pipes (10, 20) are installed symmetrically with respect to each other on the basis of the cross section and the inner and outer steel pipes (10, 20) between the sealing member 50 The high strength concrete 40 is filled between the internal and external steel pipes 10 and 20 through the injection port 52.

Stud bolts 12 are integrally fixed to the outer circumferential surface of the inner steel pipe 10, and coupling flanges 16 are integrally formed with the inner steel pipe 10 at both ends in the longitudinal direction of the inner steel pipe 10. ) Is in the direction of the outer steel pipe 20 and the width thereof is within the interval (d) between the inner and outer steel pipes 10, 20, and the reinforcement protrusions 18 are formed on the main surface of the connecting flange 16 at regular intervals. It is configured to seal the gap d with the inner and outer steel pipes 10 and 20 with the sealing member 50. The sealing member 50 is provided with an injection port 52.

It is preferable that the distance d between the inner and outer steel pipes 10 and 20 be 1 / 8-1 / 7 of the coaxial width D of the outer steel pipe.

In order to facilitate the lightweighting of the CFCT structure 100 and the injection of the high strength concrete 40.

Installation of the inner diaphragm 70 in the inner steel pipe 10 is possible.

Now, the bonding method for assembling and connecting the CFCT structure 100 of the present invention will be described.

In manufacturing a double composite tube structure consisting of inner and outer steel pipes (10, 20) of circular and polygonal, the stud bolts (12) are fixed to the outer circumferential surface of the inner steel pipe (10), and the connecting flanges are formed at both ends in the longitudinal direction thereof. 16) outwardly installing; The outer steel pipe 20 having a distance greater than d by the inner steel pipe 10 is positioned at the center of the coaxial shaft with the inner steel pipe 10 and the inner and outer steel pipes 10 and 20 by the fastening fixing bolts 30. Fixing; Sealing the gap d between the inner and outer steel pipes 10 and 20 by the sealing member 50 having the injection hole 52 formed therein; Filling the high-strength concrete 40 into the injection hole 52 of the sealing member 50; Joining method comprising the step of integrally joining the sleeve 60 to the outer peripheral surface of the outer steel pipe 20 by welding (54).

The interval d between the inner and outer steel pipes 10 and 20 is preferably 1 / 8-1 / 7 of the coaxial width D of the outer steel pipe 20.

Referring to the effects of the present invention configured as described above are as follows.

Since the high-strength concrete is filled only between the inner and outer steel pipes of a circular and polygonal shape, and the center of the inner steel pipe does not fill the concrete, the CFCT structure of the present invention has the effect of being lightweight.

The internal and external steel pipes and concrete are integrated by the fastening bolts and stud bolts because the stud bolts that are fixed to the outer circumferential surface of the internal steel pipes while being firmly fixed to the internal and external steel pipes by fastening fixing bolts. As a result, the peeling phenomenon of steel pipe and concrete does not occur.

Internal and external steel pipes and concrete behave integrally by fastening fixing bolts and stud bolts, which makes it possible to use them as horizontal members supporting bending moments and shear forces.

Since the connecting flange is formed at both ends in the longitudinal direction of the inner steel pipe, the assembly is facilitated by the high tension bolt.

In the present CFCT structure, since the inner space of the inner steel pipe is empty, not only the existing CFT structure but also the inner diaphragm can be easily installed, and it is easy to appropriately reinforce the working part of the stress regardless of the concrete filling site. It is a useful invention.

Claims (7)

delete delete delete delete delete In manufacturing a double composite tube structure consisting of inner and outer steel pipes (10, 20) of circular and polygonal, the stud bolts (12) are fixed to the outer circumferential surface of the inner steel pipe (10), and the connecting flanges are formed at both ends in the longitudinal direction thereof. 16) outwardly installing; The outer steel pipe 20 having a distance greater than d by the inner steel pipe 10 is positioned at the center of the coaxial shaft with the inner steel pipe 10 and the inner and outer steel pipes 10 and 20 by the fastening fixing bolts 30. Fixing; Sealing the gap d between the inner and outer steel pipes 10 and 20 by the sealing member 50 having the injection hole 52 formed therein; Filling the high-strength concrete 40 into the injection hole 52 of the sealing member 50; Joining method for connecting a double composite tube structure filled with high-strength concrete, characterized in that it comprises a step of integrally connecting the sleeve 60 by welding to the outer peripheral surface of the outer steel pipe (20) The high-strength concrete according to claim 6, wherein the distance d between the inner and outer steel pipes 10 and 20 is 1 / 8-1 / 7 of the diameter D of the outer steel pipe 20. Joining method for connecting the double composite tube structure filled with 40)

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