JP2001159195A - Joining structure between steel pipe member and concrete member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joining structure between a steel pipe and a concrete member excellent in fatigue resistance in simple constitution and without any weak point on the structure. SOLUTION: A plurality of ribs 22 are welded and joined on the inner face of the end of the steel pipe 22 along the axial direction of the steel pipe. These ribs are mutually joined in the neighborhood of the center part of the steel pipe, and projected to be extended from the end of the steel pipe 21. A plurality of opening holes are provided on the projection part, and embedded in the concrete member 11 joined to the steel pipe 21. In addition, concrete 25 or mortar is filled into the inside of the steel pipe of a part welded on the rib. A PC steel rod is arranged along the plurality of the ribs welded and joined in the steel pipe, projected from the end of the steel pipe, and may be embedded in the concrete member joining it. The PC steel rod is locked on the rib in the joining structure, and integrated with the steel pipe by the adhesion force of concrete or mortar filled into the steel pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be used in a concrete / steel composite structure constructed as an civil engineering structure or an architectural structure, and is used for joining a steel pipe member and a concrete member. It is related to the structure of.

[0002]

2. Description of the Related Art Concrete or steel is widely used as a structural material for civil engineering or building structures. Concrete has an advantage that a member of an arbitrary shape can be formed at a construction site and maintenance is easy, and a steel material has an advantage that a lightweight and strong structure can be constructed. And concrete / steel composite structure has been proposed as a structure taking advantage of each of the above advantages, for example,
There is a concrete / steel composite truss bridge in which the upper deck and the lower deck of road bridges and railway bridges are made of concrete, and these are connected by steel pipe diagonal members.

[0003] In such a structure, it is necessary to smoothly transmit the force at the joint between the concrete member and the steel member, to suppress the generation of large local stress, and not to cause a structural weakness. As such a joint structure between a concrete member and a steel member, for example, in a concrete / steel composite truss bridge, the upper chord, the lower chord and the diagonal of the truss are integrally assembled by a steel member, and the stud dowel is attached to the upper chord and the lower chord. A structure has been considered in which an upper floor and a lower floor made of concrete are integrated with each other. However, in such a structure, a large amount of steel is used, the construction cost becomes large, and high precision is required for assembling the steel truss, so that advantages of a composite structure of concrete and steel members cannot be utilized. .

For this reason, it is desirable to adopt a structure in which each of the steel diagonal members is directly joined to the upper slab or the lower slab of concrete, and the following joining structures have been considered. In the joining structure shown in FIG. 6, a steel plate 102 is welded to an end of a steel member 101, which is a diagonal member, substantially perpendicularly to the axis of the member.
A plurality of stud dowels 103 are erected from this steel plate.
Then, concrete is cast so as to embed the stud dowel 103 to form a concrete member 104 integrally joined with the steel member 101. The joining structure shown in FIG. 7 is similar to the example shown in FIG.
A steel plate 112 is welded to one end of the steel plate 112, and a threaded hole formed in the steel plate 112 is inserted into a rod-shaped steel material 11 such as a PC steel rod or a steel bar.
3 is screwed. Then, by embedding the PC steel bar or the steel bar in the concrete, the concrete member 114 is formed.
And the steel member 111 are integrated.

[0005]

However, the joining structure as shown in FIG. 6 or 7 has the following problems. In the structure as shown in FIG. 6, the force acting on the steel member 101 is transmitted to the concrete member 104 via the steel plate 102 at the end and the stud dowel 103 welded thereto. Therefore, the welded portion between the steel member 101 and the steel plate 102 and the welded portion between the steel plate 102 and the stud dowel 103 are required to have sufficient strength and reliability, and it is necessary to strictly control and inspect the welding process. In addition, it is difficult to use a high-strength steel material for the stud dowel 103 to be welded and joined, and the number of necessary stud dowels may increase, which may make the arrangement difficult. Further, in a composite truss bridge or the like, a force that fluctuates repeatedly acts on the joint between the concrete member and the steel member, and the steel member 101 and the steel plate 1
02 or the base of the stud dovetail 103 may cause fatigue failure.

On the other hand, in the structure as shown in FIG. 7, a high-strength steel such as a PC steel bar can be used as the bar-shaped steel material 113, and the number of bars can be reduced to simplify the structure of the joint. However, when a thread is provided on the bar-shaped steel material and a large axial force or bending moment repeatedly acts on the joint between the concrete member 114 and the steel member 111, the bar-shaped steel material 113 is formed at the portion where the thread is provided. It is possible that fatigue fracture occurs. Further, similarly to the structure shown in FIG. 6, there is a possibility that fatigue fracture may occur at the welded joint between the steel member 111 and the steel plate 112.

The invention according to the present application has been made in view of the above-mentioned problems, and an object thereof is to provide a concrete member and a steel pipe member having a simple structure, excellent fatigue resistance, and having no structural weakness. Is to provide a bonding structure.

[0008]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a plurality of ribs are provided on an inner surface of an end of a steel pipe member along an axial direction of the steel pipe member. The rib is extended and protrudes from the end face of the steel pipe member, and the protruding portion is embedded in a concrete member to be joined to the steel pipe member, and the rib is welded to a portion of the steel pipe member where the rib is welded. The present invention also provides a joint structure between a steel pipe member filled with concrete or mortar so as to be continuous with the concrete member and a concrete member.

In the joint structure between the steel pipe member and the concrete member, the tensile force acting on the steel pipe member is transmitted to the plurality of welded ribs, and further transmitted to the concrete member in which the protruding portions of the ribs are embedded. You. At this time, force is transmitted between the rib and the steel pipe member via a portion welded linearly along the axial direction of the steel pipe member,
The occurrence of locally large stresses is avoided. Further, between the concrete member and the rib, the force is transmitted by the adhesive force of the concrete distributed over a wide range, and local concentration of stress on the rib does not occur. Therefore, even when a repeated load is applied, the bearing has a large resistance to fatigue.

On the other hand, the portion where the rib is welded to the steel pipe member is filled with concrete or mortar, which is firmly adhered to the rib and the inner surface of the steel pipe member. While being protected, a part of the tensile force is transmitted through the adhesive force of concrete or mortar, and the stress of the welded portion is relieved. When a compressive force acts on the steel pipe member, a large portion of the compressive force is shared by concrete or mortar filled in the steel pipe member and adhered to the inner surface of the steel pipe member, and is reliably transmitted to the concrete member.

According to a second aspect of the present invention, there is provided a joint structure between a steel pipe member and a concrete member according to the first aspect,
It is assumed that a plurality of openings are provided in the rib in a dispersed manner.

In the joint structure between the steel pipe member and the concrete member, when the rib is embedded in the concrete member, the concrete enters into the opening and functions as a shear key. That is, the concrete that has entered the openings meshes with the ribs and transmits force. Therefore, when a tensile force or a compressive force acts on the rib, not only the adhesive force acting on the side surface of the rib but also a large force is transmitted at the opening of the rib, and the rib and the concrete member are integrated. Sex is maintained strongly.

According to a third aspect of the present invention, in the joint structure of a steel pipe member and a concrete member according to the first aspect,
The plurality of ribs provided at predetermined intervals in the circumferential direction on the inner surface of the steel pipe member are joined to each other at a central portion of the steel pipe member.

In this joint structure, the ribs are firmly attached to the steel pipe member and have high rigidity. Therefore, the rib resists a bending moment or a shearing force at the joint between the steel pipe member and the concrete member. In general, when the points of the members are rigidly connected in the truss structure, some bending moment or shear force is generated near the points of each member. However, the ribs can resist the bending moment or the shear force.

According to a fourth aspect of the present invention, a plurality of ribs are welded to an inner surface of an end portion of the steel pipe member along an axial direction of the steel pipe member, and an axial line of the steel pipe member is formed along the rib. A plurality of bar-shaped steel members are arranged in the direction, the bar-shaped steel members protrude from an end face of the steel pipe member, are embedded in a concrete member to be joined to the steel pipe member, and the ribs at the ends of the steel pipe member are welded. In addition, the present invention provides a joint structure between a steel pipe member and a concrete member, characterized by being filled with concrete or mortar so as to be continuous with the concrete member.

The invention described in claim 5 is the same as the invention in claim 4.
In the joint structure between the steel pipe member and the concrete member according to the above, the plurality of ribs are provided so that two pairs are opposed to each other at a predetermined interval, and the rod-shaped steel material is provided between the two paired ribs. And a nut screwed to the end of the bar-shaped steel material is engaged with the rib.

In such a joint structure between a steel pipe member and a concrete member, the tensile force acting on the steel pipe member is transmitted to the plurality of welded ribs, and the concrete or mortar filled at the end of the steel pipe member is further filled. Is transmitted to the bar-shaped steel material by the adhesive force. Further, when the bar-shaped steel material is locked by the rib as described in claim 5, the force is transmitted also through this locked portion. The rod-shaped steel material has a portion protruding from the end face of the steel pipe member embedded in the concrete member, and the force transmitted to the rod-shaped steel material is applied to the concrete by adhesion of the concrete or by a nut, a plate, or the like locked to the end of the rod-shaped steel material. Transmitted to the member. On the other hand, the compressive force acting on the steel pipe member is transmitted to the concrete member via concrete or mortar filled in the end face of the steel pipe member or the inside of the end of the steel pipe member.

In such a joint structure, the rib is welded along the axial direction of the steel pipe member, and a force is transmitted in a wide range, so that the stress acting on the welded portion is small.
It is possible to prevent the welded portion from becoming a weak point against fatigue. Further, the rib and the bar-shaped steel material are integrated by the adhesive force of the concrete or mortar, and the force is dispersed and transmitted in a wide range, so that the possibility that the bar-shaped steel material is fatigued can be eliminated. Further, the rod-shaped steel material is locked to the rib by the nut as described in claim 5, thereby sharing the adhesive force of concrete or mortar and transmitting the force from the locked portion. Reliability can be improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view and a sectional view showing a concrete / steel composite truss bridge to which a joint structure between a steel pipe member and a concrete member according to an embodiment of the present invention is applied. This composite truss bridge has a continuous truss 2 supported on a plurality of piers 1a and 1b and an abutment (not shown). The truss structure includes an upper deck 11 made of prestressed concrete and The main part is composed of a lower floor slab 12 of prestressed concrete supported by a slab, and a steel pipe diagonal member 13 connecting the upper floor slab 11 and the lower floor slab 12, and the upper floor slab 11 is used as an upper chord material, Reference numeral 12 functions as a lower chord material.

The upper floor slab 11 is continuous in the axial direction of the bridge, on which a road surface is formed, and a PC steel material (not shown) is buried in the axial direction and at right angles thereto. Prestress is introduced by tensioning these PC steel materials and fixing them to concrete, so that even when a compressive force or a tensile force due to functioning as the upper chord material acts, harmful cracks and the like do not occur. It has become. On the other hand, the prestress is also introduced into the lower floor slab 12 in the axial direction of the bridge, so that the lower slab 12 can withstand the compressive and tensile forces caused by functioning as the lower chord of the truss. The diagonal members 13 are arranged so as to be inclined in the axial direction of the bridge, and the diagonal members 13a and 13b whose inclination directions are reversed.
Are alternately arranged to form a warren truss. Each of the diagonal members 13a, 13b has an upper floor slab
And the lower deck 12.

FIG. 2 shows a joint between a concrete upper slab 11 and a diagonal member made of a steel pipe, which can be applied to the concrete / steel composite truss bridge, and shows a steel pipe member and a concrete member according to an embodiment of the present invention. It is sectional drawing which shows the joining structure with this. FIG. 3 is a schematic perspective view of the same joint structure. In this joining structure, a plurality of ribs 22 are welded to the inside of the end of the steel pipe 21 and the ribs 22 are joined together.
Is projected from the end face of the steel pipe 21, and the projected portion 22a is embedded in the upper floor slab 11, which is a concrete member.

The steel pipe 21 is joined so that its end face abuts on the upper slab 11, and the end face is formed in a shape along the concrete surface of the upper slab. In this embodiment, the diagonal member made of the steel pipe 21 is joined to the lower surface of the upper slab thickening portion 11a formed in a substantially horizontal direction, and the end surface is formed to be parallel to the lower surface. A protective plate 2 is provided on the outer peripheral surface of the end of the steel pipe.
3 is provided so as to protrude to prevent rainwater or the like from entering the steel pipe. The steel pipes may be joined in a state where a predetermined length of the end is inserted into the concrete member.

The ribs 22 are steel plates joined by welding in four directions on the inner peripheral surface of the steel pipe 21 in the axial direction of the steel pipe 21. The ribs 22 are continuous with each other at the center of the steel pipe 21, and four ribs are formed in the steel pipe 21. The shape is divided into two. The rib 22 protrudes from the end face of the steel pipe 21, and the protruding portion 22 a has a cross-shaped cross section and is embedded in the concrete of the upper floor slab 11. The rib 22 is provided with a plurality of circular holes 22b, and when embedded in concrete, concrete enters into the circular holes.

On the steel pipe 21 slightly behind the portion where the ribs 22 are welded, the steel plate 2 is perpendicular to the axis of the steel pipe.
4 are welded. The steel plate material 24 functions as a formwork for the concrete 25 filled inside the end of the steel pipe.

The concrete 25 filled inside the end of the steel pipe 21 can be filled at the same time as the concrete of the upper slab 11 is cast. That is, after temporarily fixing the steel pipe 21 to which the rib 22 is attached at a predetermined position, concrete of the upper floor slab 11 is poured, and concrete is poured into the steel pipe 21 from the opening at the upper end of the steel pipe, and the welded portion of the rib 22 is removed. Fill to fill.

The concrete 25 to be filled inside the end of the steel pipe may be previously filled and hardened before the steel pipe 21 is erected at a predetermined position. In particular, it is difficult to fill the lower end of the steel pipes arranged diagonally at the same time as placing the concrete on the lower floor slab, and it is desirable to fill the steel pipes in advance. In addition, by filling the upper end portion of the steel pipe in advance, it is possible to reliably fill the steel pipe, and it is easy to fill the steel pipe without leaving a cavity. When the steel pipe is filled in advance as described above, a mortar or cement grout material or the like can be used instead of concrete. May be provided.

In such a joint structure between a steel pipe member and a concrete member, the tensile force acting on the steel pipe 21 is reduced by the ribs 22.
Is transmitted to the concrete of the upper slab 11 via the An adhesive force acts between the rib 22 and the concrete, and the concrete is firmly integrated by entering the plurality of circular holes 22b of the rib 22, so that the rib 22 comes out of the concrete. The transmission of force is performed without fail. Further, the bending moment and the shearing force are also transmitted by the rib 22. And a welded part does not become a weak point, and it becomes a joining structure excellent in fatigue resistance characteristics.

In the warren truss as shown in FIG. 1, the diagonal members made of the above-mentioned steel pipe 21 are provided adjacent to each other in such a manner that the inclination direction is reversed. The other is a diagonal member 13b to which a compressive force mainly acts. At the joint with the steel pipe 31 where compression force mainly acts,
Although the length of the rib 32 embedded in the concrete member is slightly shortened, the compressive force is surely transmitted through the rib 32 and the end face of the steel pipe 31 and further through the concrete filled in the end of the steel pipe 31. Is transmitted.

FIG. 4 shows an embodiment of the invention according to claim 4 or 5, wherein a steel pipe member and a concrete member which can be used for a concrete / steel composite truss bridge as shown in FIG. It is sectional drawing of the joining structure of. Also,
FIG. 5 is a schematic perspective view of the same joining structure. In this joint structure, a plurality of pairs of ribs 42 are welded to the inside of the end of the steel pipe 41, and a PC steel rod 46 is disposed between the pair of ribs in the axial direction of the steel pipe 41. Have been. The PC steel bar 46 partially projects from the end of the steel pipe 41 and is embedded in the concrete of the upper floor slab 11. The portion of the steel pipe where the PC steel bar 46 is arranged is filled with concrete 45.

As in the embodiment shown in FIGS. 2 and 3, the steel pipe 41 is joined so that its end face abuts on the upper slab 11, and has a shape along the surface of the concrete of the upper slab 11. An end face is formed.

The ribs 42 are formed by welding the long sides of a strip-shaped steel sheet material in the axial direction of the steel pipe 41. The two ribs forming a pair are opposed to each other at an interval that allows the PC steel rod 46 to be inserted. And four such pairs are provided in the circumferential direction. An end plate 47 is attached to the end on the back side, and a PC steel bar 46 to which a nut 48 is screwed is locked.

The PC steel bar 46 is a deformed steel bar in which a convex portion is provided substantially uniformly on the peripheral surface over the entire length, and the convex portion is provided in a spiral shape. The helical projection has an effect of increasing the adhesive force to concrete and has a function as a screw thread for screwing and locking the nut 48.

A nut 49 is screwed into an end portion of the PC steel bar 46 embedded in the upper floor slab 11, and an anchor plate 50 is locked. Thus, when a large pulling force acts on the PC steel rod 46, not only the adhesive force on the peripheral surface but also the anchor plate 50 can resist. However, in the diagonal material where compressive force mainly acts, P
No large pulling force acts on the C steel rod, and the anchor plate is not provided.

The concrete 45 to be filled inside the end of the steel pipe can be filled at the same time as the concrete of the upper floor slab 11 is poured. Mortar or cement grout may be pre-filled for sufficient adhesion. In addition, the steel plate material 44 which is another structure of this joining structure,
The protection plate 43 and the like are the same as those shown in FIG. 2 or FIG.

In such a joint structure, the tensile force applied to the steel pipe 41 is transmitted from the rib 42 to the PC steel rod 46 via the adhesive force of the concrete 45 and the nut screwed to the PC steel rod 46. Conveyed via 48. Further, the PC steel rod 46 is transmitted to the upper floor slab 11 by the adhesive force of concrete and the anchor plate 50. By dispersing the forces in this manner, a structure in which stress is less concentrated locally and excellent in fatigue resistance is obtained. The concrete 45 filled inside the steel pipe 41 is continuous with the concrete of the upper slab 11,
This concrete resists shear forces.

The embodiment described above is applied to concrete
It is applied to the joint between the steel pipe diagonal and the upper slab of the steel composite truss bridge, but it can also be applied to the joint between the steel pipe diagonal and the lower slab, and it can be applied to structures other than bridges such as building structures. Can be applied.

[0037]

As described above, in the joint structure of a steel pipe member and a concrete member according to the present invention, the rib fixed to the end of the steel pipe for transmitting a force is distributed in the axial direction of the steel pipe. , And the force is dispersed and transmitted, so that stress concentration is small and fatigue resistance is excellent. In addition, even when a bar-shaped steel material is used, the tensile force is dispersed and transmitted between the bar-shaped steel material and the steel pipe and between the bar-shaped steel material and the concrete member, and stress is less concentrated. Safety can be sufficiently ensured.

[Brief description of the drawings]

FIG. 1 is a schematic side view and a sectional view of a concrete / steel composite truss bridge to which a joint structure between a concrete member and a steel pipe member according to an embodiment of the present invention is applied.

FIG. 2 is a joint structure of a diagonal member and an upper slab which can be applied to the concrete / steel composite truss bridge shown in FIG. 1, and one embodiment of the invention according to claim 1, 2 or 3; It is sectional drawing which shows the joining structure of the steel pipe member which is a form, and a concrete member.

FIG. 3 is a schematic perspective view of the joining structure shown in FIG. 2;

FIG. 4 is a joint structure of a diagonal member and an upper slab which can be applied to the concrete / steel composite truss bridge shown in FIG. 1, and is a steel pipe which is an embodiment of the invention according to claim 4 or 5; It is sectional drawing which shows the joining structure of a member and a concrete member.

5 is a schematic perspective view of the joining structure shown in FIG.

FIG. 6 is a schematic sectional view showing an example of a conventionally known joining structure between a steel pipe member and a concrete member.

FIG. 7 is a schematic sectional view showing another example of a conventionally known joining structure between a steel pipe member and a concrete member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bridge pier 2 Continuous truss 11 Upper floor slab 12 Lower floor slab 13 Diagonal member 13a Diagonal member mainly subjected to tensile force 13b Diagonal member mainly subjected to compressive force 21, 41 Steel pipe 22, 42 Rib 23, 43 Protective plate 24, 44 Steel plate material 25, 45 Concrete 31 Steel pipe 32 Rib 46 PC steel bar 47 End plate 48, 49 Nut 50 Anchor plate

Claims (5)

[Claims] A plurality of ribs are welded to an inner surface of an end portion of the steel pipe member along an axial direction of the steel pipe member, and the rib is extended and protrudes from an end face of the steel pipe member. The concrete or mortar is embedded in a concrete member to be joined to the steel pipe member, and a portion of the steel pipe member to which the rib is welded is filled with concrete or mortar so as to be continuous with the concrete member. Joint structure between steel pipe members and concrete members. 2. The joint structure between a steel pipe member and a concrete member according to claim 1, wherein a plurality of openings are provided in the rib in a distributed manner. 3. A plurality of ribs provided at predetermined intervals in a circumferential direction on an inner surface of the steel pipe member, wherein the plurality of ribs are joined to each other at a central portion of the steel pipe member.
A joint structure between a steel pipe member and a concrete member according to the above. 4. A plurality of ribs are welded to an inner surface of an end portion of the steel pipe member along an axial direction of the steel pipe member, and a plurality of rod-shaped steel materials are formed along the rib in the axial direction of the steel pipe member. The bar-shaped steel material is disposed and protrudes from an end face of the steel pipe member, is embedded in a concrete member joined to the steel pipe member, and is continuously connected to the concrete member at a portion where the rib at the end of the steel pipe member is welded. A joint structure between a steel pipe member and a concrete member, characterized by being filled with concrete or mortar. 5. The plurality of ribs are provided so as to face each other at predetermined intervals in pairs, wherein the bar-shaped steel material is disposed between the paired two ribs, and an end of the bar-shaped steel material is provided. The joint structure between a steel pipe member and a concrete member according to claim 4, wherein a nut screwed into the portion is locked by the rib.