JPH05311746A - Concrete-filled steel pipe structure - Google Patents

Abstract

(57) [Summary] [Purpose] A highly reliable concrete-filled steel pipe with a simple structure, sufficient yield strength at the joint, excellent workability and cost, and excellent durability as a frame assembly. Provide structure. [Structure] Inside the upper and lower hollow outer tubular pipes 1, the ends of the hollow inner tubular pipes 2 serving as points are inserted for a predetermined length, and concrete 3 is filled into the hollow outer tubular pipes 1 and the hollow outer tubular pipes 1. The inner tube 2 is joined. A diaphragm 4 and a beam joint 5 having an H-shaped cross section are provided in advance in the intermediate portion of the hollow inner tubular tube 2, and a beam 6 is joined with a bolt 8 using a splice plate 7. Protrusions are provided on the outer surface of the hollow inner tubular pipe 1 by, for example, stud dowels being melted therein so as to be integrated with the concrete 3. If an unbonding treatment is applied between the inner surface of the hollow outer cylinder tube 1 and the concrete 3, local buckling of the hollow outer cylinder tube 1 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete-filled steel pipe structure (not limited to a steel pipe as will be described later) in a structure, particularly to a structure of a joint between frame members, a building frame, a port, an ocean. It is used for piers as structures and pipe structures such as oil drilling rigs.

[0002]

2. Description of the Related Art Since a concrete-filled steel pipe structure has excellent strength and durability as a composite member, it can be said to be a structure suitable for a structural member in a large structure or an important structure. However, it has a structure in which steel pipes with closed cross sections are filled with concrete, and when used as a frame assembly, joining at joints is not always easy, and in order to obtain a structure with high strength reliability, The joint structure and the like in the part are important. Conventionally, as a joining method applicable to a concrete-filled steel pipe structure, a method of butt welding the ends of the steel pipes forming the concrete-filled steel pipe structure, or forming a flange at the ends of the steel pipe and bolting the flanges together There is a method of doing so, and concrete can be filled in a state where steel pipes are joined. Further, at the joint between the column and the beam in the building frame, a diaphragm is provided at the height of the upper and lower flanges of an H-shaped steel beam, and the beam is bolted or welded to the diaphragm, for example, Japanese Patent Laid-Open No. 63-251.
There is known a structure in which an insertion diaphragm having a bolt hole as described in Japanese Patent No. 540 is inserted into a steel pipe column and an end plate provided at an end portion of a steel beam is bolted. Further, an example of applying the concrete-filled steel pipe structure to a bridge pier such as a road bridge is disclosed in Japanese Patent Publication No. 3-54724. In the invention described in this publication,
The unbonded state between the steel pipe and the concrete filled inside the steel pipe and the gap between the upper end of the steel pipe and the upper beam of the bridge pier reduce the compressive force acting on the steel pipe and buckle the steel pipe. As a result, the effect of restraining the filled concrete is prevented from being impaired, and it is possible to improve the strength against a compressive load in the axial direction and reduce the cross section.

[0003]

The method of joining steel pipes by butt welding has the problems of reliability of on-site welding, deterioration of welded parts, and the need for skilled welders. In addition, the method of bolt connection using the flange of the end requires processing for bolt connection, and when accuracy is poor, problems such as difficulty in bolt connection in the field and long shaft members If a flange is provided at the end of the, there is a problem that the flange becomes an obstacle during transportation. Even if it is not so difficult to join the steel pipes linearly in any of the methods, it is not possible to directly apply the point where the shaft members are joined to each other in the pipe structure or the beam structure. In the method in which the diaphragm is installed at the flange height of the beam, the steel pipes that make up the columns, etc. are divided by the beam height and welded with the diaphragm sandwiched, but this is an important position for stress transmission as a panel zone. Therefore, it often has a complicated structure such as reinforcement. In addition, when concrete is poured into the steel pipe, the diaphragm may hinder the filling of the concrete, or the concrete may not sufficiently wrap around the lower surface of the inner protruding portion of the diaphragm. The internal diaphragm doubles as a reinforcement for the panel zone to some extent, but it is necessary to form a female thread in the internal diaphragm, and also a bolt insertion hole must be drilled in the steel pipe, and high dimensional accuracy is required. For example, there is a problem in that processing is expensive. Moreover, since it is mainly intended for square steel pipes, it becomes more difficult to process it in order to apply it to circular steel pipes.

Further, when considering a building frame, a jetty, a rig for oil drilling, and other pipe structures, the pipe surface such as a steel pipe as a structural member is usually thickened for the purpose of ensuring weather resistance. It is necessary to apply a film-type heavy anticorrosion coating or to perform surface treatment by plating such as zinc plating and aluminum plating. In that case, in order to reduce the painting work and the like at the site, it is desirable to carry in and assemble the members that have been subjected to surface treatment in advance. However, in a structure that requires on-site welding or bolt joining, a pipe that has been surface treated cannot be used, or even if it can be used, the joint will be damaged by on-site welding or bolt joint processing,
Since it is necessary to repair the surface-treated part such as painting again, there is a problem that corrosion is frequently caused due to poor quality of the part. The present invention is intended to solve the problems in the conventional techniques as described above, a simple structure, sufficient yield strength at the joint is obtained, and also excellent in workability and cost, further building structure It is an object of the present invention to provide a highly reliable concrete-filled steel pipe structure which is excellent in strength as a frame member when used as a pipe structure.

[0005]

The concrete-filled steel pipe structure of the present invention is mainly intended for application to a pipe structure such as a building frame, a jetty, an oil drilling rig, etc. Using the inner cylinder tube 2 and the hollow outer cylinder tube 1 that constitutes the frame assembly, the hollow inner cylinder tube 2 is inserted into the hollow outer cylinder tube 1 having a larger diameter for a predetermined length to form the hollow inner cylinder tube 2 and the hollow inner cylinder tube 2. By filling the outer cylinder pipe 1 with concrete 3, the hollow inner cylinder pipe 2
And the hollow outer tube 1 are connected and integrated. The hollow inner cylindrical tube 2 and the hollow outer cylindrical tube 1 are usually steel tubes,
For example, a stainless steel pipe or any other pipe that can be filled with concrete and used as a structural member can be applied without being limited to a steel pipe. Moreover, the cross-sectional shape of a round tube, a square tube, or the like is not limited. The hollow inner tubular tube 2 that constitutes the grade is
At the end of the hollow outer cylindrical tube 1, the concrete 3 inside and outside the hollow inner cylindrical tube 2 is constrained, but in order to ensure the transmission of stress, the concrete 3 on the outer surface of the hollow inner cylindrical tube 2 It is desirable to provide a protrusion such as a stud dowel on the contact portion. The protrusions prevent separation or slippage on the contact surface between the outer surface of the hollow inner tubular pipe 2 and the concrete 3, and in addition to the adhesive force with the concrete 3, the axial stress is smooth due to the bearing pressure at the protrusions. Transmitted. It is also possible to provide a protrusion on the inner surface of the hollow inner cylindrical tube 2. The protrusion is obtained by welding the stud dowel, or by forming the hollow inner cylindrical pipe 2 with a steel plate with a protrusion, or by welding a reinforcing bar to a circular ring or a spiral line at the pipe joint portion of the hollow inner cylindrical pipe 2. be able to. Hollow outer tube 1
As for the above, it is considered that the inner surface is subjected to an unbonding treatment by applying asphalt, grease or the like to the non-adhered state. That is, the concrete 3 filled inside exhibits a high compressive strength in the axial direction of the tube because the outside is constrained by the hollow outer tube 1, but the non-adhered state causes the compressive force in the axial direction of the tube. Hollow outer tube 1
Yield and local buckling are prevented, and the concrete restraining effect is maintained, so that a large proof stress is exerted against the compressive force in the axial direction of the pipe and the cross section can be reduced.

When the hollow outer cylinder tube 1 is structurally less likely to be locally buckled, conversely, the hollow outer cylinder tube 1 is also provided with a protrusion on the inner surface thereof in contact with the concrete 3. Therefore, a structure may be adopted in which stress is smoothly transmitted between the concrete and the hollow outer tube 1. In the case of a building frame or pipe structure, etc., when the hollow outer cylinder tube 1 constitutes a pillar, a horizontal cross member such as a beam or a brace or the like can be bolted or welded in advance to the outer surface of the hollow inner cylinder tube 2 of a high grade. If you provide a joint for the bridge,
Construction on site becomes easy. Further, as the hollow inner cylindrical tube 2 and the hollow outer cylindrical tube 1, it is possible to use a steel tube or the like whose surface is previously subjected to a thick film type heavy anticorrosion coating or a surface treatment such as zinc plating or aluminum plating. That is, in the present invention, since the hollow inner cylindrical pipe 2 and the hollow outer cylindrical pipe 1 are joined by filling the concrete 3 into the pipe including the joint portion, the pipe which has been surface-treated in advance is used as it is. Therefore, it is possible to perform the joining without impairing the surface treatment effect, and the repair work of the surface treatment damaged portion in the field as in the case of welding or bolt joining is not required.

[0007]

EXAMPLES Next, the illustrated examples will be described. FIG. 1 shows an outline of a concrete-filled steel pipe structure of the present invention, which corresponds to a joint portion between a column and a beam. The ends of the hollow inner cylindrical pipes 2 that form the points (portion) are inserted into the upper and lower hollow outer cylindrical pipes 1 that form the pillars at the joints for a predetermined length. Filling 3 constitutes a concrete-filled steel pipe structure. Hollow inner tube 2
Both ends are fixed and fixed by the concrete 3 filled in the inside and between the inner surface of the hollow outer cylindrical tube 1 and the outer surface of the hollow inner cylindrical tube 2. Further, in the illustrated example, a diaphragm 4 and a beam joint portion 5 having an H-shaped cross section are provided in the middle portion of the hollow inner cylindrical tube 2, and a beam 6 made of H-shaped steel is joined with a bolt 8 via a splice plate 7. ing. In this embodiment, the beam 6 is made of H-shaped steel, but a beam having a steel pipe structure or a concrete-filled steel pipe structure may be used.

FIG. 2 shows a vertical cross section of a graded portion in one embodiment of the present invention. A large number of studs are provided on the outer surface of the hollow inner cylindrical tube 2 to be inserted into the hollow outer cylindrical tube 1. Gibel 9 is melted (see FIG. 7). The stud dowels 9 are attached to the outer surface of the hollow inner tube 2 and the concrete 3 filled in the hollow outer tube 1 (between the inner surface of the hollow outer tube 1 and the outer surface of the hollow inner tube 2). The peeling is prevented, the adhesive force is increased, and the stress in the axial direction of the pipe is smoothly transmitted. Instead of welding the stud dowels 9, as shown in FIG. 6, the reinforcing bars 12 are welded in a spiral shape or an annular shape, or a steel tube made of a steel plate with a protrusion is used as the hollow inner cylindrical tube 2, and Can be expected to improve. Further, if the inner surface of the hollow inner cylindrical tube 2 is provided with a stud dowel, a reinforcing bar, or a projection made of a steel tube with a projection,
The integrity of the hollow inner tubular tube 2 and the concrete 3 in the hollow inner tubular tube 2 can be enhanced.

On the other hand, in the present embodiment, the unbonded layer 10 is formed on the inner surface of the hollow outer tube 1 by applying asphalt to prevent adhesion of the concrete 3 filled inside. FIG. 3 shows the operation in that case (except the pipes 1 and 2 are omitted). Since the hollow outer cylinder pipe 1 is in a non-adhesive state with the concrete inside, the hollow inner cylinder pipe is shown. The axial force N received from 2 is taken only by the filled concrete inside, and the bending moment M is taken only by the hollow outer tube 1. In this case, the axial stress acting on the hollow outer cylindrical tube 1 is only a bending moment component, and buckling becomes difficult. Therefore, the constraint of the hollow outer tube 1 to the inside in the radial direction with respect to the concrete 3 is not impaired, and the filled concrete 3 can maintain high compressive strength.

FIG. 4 shows a vertical cross section of a graded portion in another embodiment of the present invention. In contrast to the hollow outer cylinder tube 1 and the concrete 3 which are not attached in the embodiment of FIG. In the present embodiment, the stud dowels 9 are welded to the inner surface of the hollow outer tube 1, and the adhesive force with the concrete 3 is increased. When there is no concern about buckling or the like of the hollow outer cylindrical tube 1, by increasing the adhesive force by the protrusions in this way, the hollow outer cylindrical tube 1,
The integrity of the hollow inner tubular tube 2 and the filled concrete 3 can be enhanced.

FIG. 5 shows an outline of the case where the present invention is applied to a pipe structure or the like. The hollow inner cylindrical tube 2 used for the marking is shown.
The hollow outer cylindrical tube 1 used as a frame member is joined via filled concrete, and the points are connected by the beam 6 or the brace 11 as a horizontal member to form a frame member. .. In the above embodiments, the hollow outer cylinder tube 1 and the hollow inner cylinder tube 2 are used in the up-down direction and joined in the up-down direction, but horizontal joining can be performed in the same manner if necessary. It is also possible to provide a branch in the hollow inner cylindrical tube 2 forming a grade and join in multiple directions. Furthermore, on the outer surface of the hollow outer tube 1, a thick film type heavy anticorrosion coating or zinc plating,
You may perform surface treatment by aluminum plating.

[0012]

The present invention has the following effects. Hollow inner tube 2 that forms a score at the score position
And the hollow outer cylindrical tube 1 as the frame assembly are overlapped with each other for a predetermined length and are joined through the concrete 3 filled between them, so that the structure of the joining portion is simplified. Regarding the joining of the hollow outer cylindrical tube 1 and the hollow inner cylindrical tube 2,
There is no need for on-site welding or bolt joining, and steel pipes can be used as they are. In addition, hollow outer tube 1
Further, the yield of the hollow inner cylindrical tube 2 does not require so high accuracy. The hollow outer cylindrical tube 1 and the hollow inner cylindrical tube 2 are joined by filling the joint portion with concrete 3, and since on-site welding or bolt joining is not required, surface treatment such as painting or plating is performed in advance. A tube can be used. Further, it is possible to omit the on-site repair work for the surface treatment damaged portion due to the welding and the processing of the bolt joint portion, and the on-site work can be simplified. Regarding the filling of concrete into the inside of the pipe, since there is no obstacle such as a diaphragm inside the pipe to fill the concrete, the concrete filling work is easy and a concrete-filled steel pipe structure having no defects can be obtained. When the inner surface of the hollow outer cylinder tube 1 and the filled concrete 3 are made unbonded by an unbonding process, the filled concrete inside exhibits a high compressive strength and the member cross section can be reduced. It is configured as a separate member, and the end portion of the hollow outer tube 1 does not need to be processed in particular and has no protrusion, so that it is easy to carry. In addition, since the hollow inner cylindrical tube 2 is of a short length, it is possible to preliminarily form a connecting portion with a multi-directional frame assembly member,
Site work becomes easy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a joint portion in an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a joint portion according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing transmission of stress in the embodiment of FIG.

FIG. 4 is a vertical sectional view of a joint portion according to another embodiment of the present invention.

FIG. 5 is a front view showing an outline when the present invention is applied to a pipe structure.

FIG. 6 is a front view of a steel pipe end portion when a spirally welded reinforcing bar is used as a protrusion.

FIG. 7 is a front view of a steel pipe end portion when a stud dowel is used as a protrusion.

[Explanation of symbols]

 1 Hollow Outer Tube 2 Hollow Inner Tube 3 Concrete 4 Diaphragm 5 Beam Joint 6 Beam 7 Splice Plate 8 Bolt 9 Stud Gibel 10 Unbonded Layer 11 Brace 12 Reinforcing Bar

Claims (6)

[Claims] 1. A hollow inner cylindrical tube 2 constituting a point is inserted into a hollow outer cylindrical tube 1 constituting a frame assembly by a predetermined length, and is inserted into the hollow inner cylindrical tube 2 and the hollow outer cylindrical tube 1. Concrete-filled steel pipe structure, characterized in that the hollow inner tubular pipe 2 and the hollow outer tubular pipe 1 are joined and integrated by filling with concrete. 2. A projection is provided on a portion of the outer surface of the hollow inner tubular tube 2 which comes into contact with the concrete 3.
Concrete filled steel pipe structure. 3. The concrete-filled steel pipe structure according to claim 1, wherein an unbonding treatment is applied between the inner surface of the hollow outer cylinder tube 1 and the concrete 3 filled in the hollow outer cylinder tube 1. 4. The concrete 3 of the hollow outer tube 1
The concrete-filled steel pipe structure according to claim 1 or 2, wherein a projection is provided at a portion contacting with. 5. The hollow outer cylindrical tube 1 constitutes a column as a frame assembly, and the outer surface of the hollow inner cylindrical tube 2 is a horizontal frame for bolting or welding a horizontal frame as a frame assembly. The concrete-filled steel pipe structure according to claim 1, 2, 3, or 4, wherein a joint portion is provided. 6. The concrete-filled steel pipe structure according to claim 1, 2, 3, 4, or 5, wherein the outer surface of the hollow outer tube 1 is surface-treated in advance.