JP2011163047A - Joint structure of steel frame member and reinforced concrete member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an effective and proper joint structure for joining a steel frame member such as a beam steel frame, a column steel frame or the like with a reinforced concrete member such as a beam end made of RC and encasing concrete. <P>SOLUTION: This joint structure is constituted by insulating the steel frame member to be unable to transmit a stress to the reinforced concrete member by using a scope of the reinforced concrete member having the predetermined dimension L from its surface as a stress concentrating part among burying parts of the reinforced concrete member (the beam end 2b) burying the steel frame member (the beam steel frame 2a), providing an insulating material 4 to prevent transmission of the stress between the reinforced concrete member and the steel frame member in the stress concentrating part, and gradually reducing the thickness of the stress concentrating part from the surface of the reinforced concrete member toward its tip side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for joining structural members in a building, and more particularly, to a joining structure of a steel frame member and a reinforced concrete member.

As a structure of a building, for example, as shown in Patent Document 1, a composite structure combining a steel structure (S structure) and a reinforced concrete structure (RC structure) is known.
As schematically shown in FIG. 10, this is a combination of an RC column 1 and an S beam 2 mainly composed of a beam steel frame 2a, and only the beam end 2b of the beam 2 is RC. As a structure, it is structurally integrally joined to the column 1 via an anchor bar (not shown).

In addition, it can be said that such a structure is a structure in which the end of the beam steel 2a as the steel member is embedded in the beam end 2b as the reinforced concrete member (RC member) provided integrally with the column 1, Such a beam end portion 2b can be said to be a steel-framed reinforced concrete member (SRC member) as a result since a steel-frame member is embedded.
In addition, the beam end 2b may be formed by precast concrete in addition to being constructed as an on-site RC structure.

JP 2006-144535 A

By the way, in the composite structure of the S structure and the RC structure as described above, as shown in FIG. 11, the vertical load P acting on the beam steel 2a which is the main body of the beam 2 is embedded in the end of the beam steel 2a. The beam is supported by the reaction forces R ₁ and R ₂ from the beam end 2b, but at this time, the upward force generated on the front side compared to the downward reaction force R ₂ generated on the tip side of the beam steel frame 2a. since towards the reaction force R ₁ becomes large, the structure of the conventional this type will be large stress concentration at the tip side of the beam end 2b of the RC member is caused, due to that in FIG. 11 (b) As shown, cracks and peeling may occur on the tip surface of the beam end 2b.
Even if damage such as cracking or peeling occurs, it is insignificant and does not affect the ultimate strength required for the beam end 2b. Is not preferable because it is necessary.

  This is not only the case of the S-shaped beam 2 as described above, but also the case where the column base of the S-shaped column 3 is made of RC as shown in FIG. 12, that is, the column of the column steel frame 3a. The same occurs when the root-wrapped concrete 3b is provided on the leg, and in this case, the horizontal load acting on the column steel 3a may cause cracking or peeling off on the top surface of the root-wrapped concrete 3b as shown in (b). .

  In view of the above circumstances, the present invention cracks the reinforced concrete members in the case of joining steel members such as beam steel and column steel to reinforced concrete members such as beam ends and root wound concrete in this type of composite structure. Another object of the present invention is to provide an effective and appropriate joint structure capable of preventing the occurrence of peeling.

  The invention according to claim 1 is a structure for embedding an end portion of a steel member in a reinforced concrete member and joining the steel member and the reinforced concrete member, wherein the reinforced concrete member is embedded in the steel member. Among them, the range of a predetermined dimension L from the surface of the reinforced concrete member is defined as a stress concentration portion, and the stress concentration portion insulates the steel frame member so as not to transmit stress to the reinforced concrete member, and the stress concentration in the embedded portion. The steel member is integrated so that stress can be transmitted to the reinforced concrete member on the entire tip side from the portion.

  The invention according to claim 2 is the joining structure of the steel member and the reinforced concrete member according to claim 1, and insulates the reinforced concrete member and the steel member at the stress concentration portion so that stress cannot be transmitted. Is provided.

  The invention according to claim 3 is the joining structure of the steel member and the reinforced concrete member according to claim 1 or 2, wherein the thickness dimension of the stress concentration portion is directed from the surface of the reinforced concrete member toward the tip side. It is characterized by being gradually reduced.

  According to the present invention, the stress concentration portion is set in the vicinity of the surface of the reinforced concrete member in which the steel member is embedded, and the stress concentration in the vicinity of the surface of the reinforced concrete member is reduced by insulating the steel member and the reinforced concrete member there. It is possible to prevent cracks and peeling off.

It is a figure which shows one Embodiment in the case of joining a beam steel frame to the RC beam end part by the joining structure of this invention. It is a figure which shows other embodiment same as the above. It is a figure which shows other embodiment same as the above. It is a figure which shows other embodiment same as the above. It is a figure which shows other embodiment same as the above. It is a figure which shows other embodiment same as the above. It is a figure which shows one Embodiment in the case of joining a column steel frame to RC reinforced concrete with the joining structure of this invention. It is a figure which shows other embodiment same as the above. It is a figure which shows other embodiment same as the above. It is a figure which shows an example of the conventional composite structure. It is a figure which shows a junction part similarly. It is a figure which shows the other example of the conventional composite structure.

FIG. 1 shows an embodiment of the present invention.
This embodiment is an application example to a composite structure with RC columns 1 and S beams 2 as shown in FIGS. 10 to 11, and basically, as in the conventional case, beams The beam end 2b of the beam 2 is an RC structure and the end of the beam steel frame 2a as the main body of the beam is embedded, that is, the beam end 2b as a reinforced concrete member (RC member) and the beam steel frame 2a as a steel member. Are embedded and structurally joined together.
Also in this embodiment, as shown in Patent Document 1, the beam end 2b may be joined to the column 1 via an anchor bar, and the beam end 2b as an RC member is made of precast concrete. It may be formed.

Conventionally, the entire end of the beam steel frame 2a is simply embedded in the beam end 2b, and the entire end is integrated in a state where stress can be transmitted to the beam end 2b. Then, in the vicinity of the surface of the beam end portion 2b, the main purpose is to insulate them without integrating them, that is, to structurally cut the edges.
That is, in the present embodiment, as shown in FIG. 1 (a), the stress concentration is within a range of a predetermined dimension L from the distal end surface of the beam end portion 2b among the embedded portion of the beam end portion 2b in which the beam steel frame 2a is embedded. As a part, in the stress concentration part, the beam steel frame 2a is insulated from the beam end part 2b so as not to transmit stress, and then the beam steel frame 2a is entirely attached to the beam member 2b on the tip side of the stress concentration part. They are integrated so that stress can be transmitted.

In order to insulate the beam steel frame 2a and the beam end 2b at the stress concentration portion, as shown in FIG. 1 (b), the insulating material 4 is attached to the upper surface of the upper flange and the lower surface of the lower flange, respectively. In this way, the stress concentration portion can be structurally edged so that the insulating material 4 prevents their integration and prevents stress transmission.
The insulating material 4 is not particularly limited as long as it has a sufficiently small elastic coefficient compared with concrete, but rubber, for example, can be suitably used. The width L and thickness of the insulating material 4 may be set as appropriate so that stress is not transmitted because the insulating state with respect to the beam end 2b is maintained even when the beam steel frame 2a is deformed. For example, the width L is 50 mm. A thickness of about 5 mm is sufficient.

As described above, the stress concentration portion is set in the vicinity of the distal end surface of the beam end portion 2b, and the beam steel frame 2a and the beam end portion 2b are structurally insulated, so that the beam end is caused by the vertical load acting on the beam steel frame 2a. The position of the reaction force point generated in the portion 2b is displaced to the distal end side of the beam steel frame 2a as compared with the prior art, thereby reducing the stress concentration on the distal end portion of the beam end portion 2b, and as a result, on the distal end surface of the beam end portion 2b. It is possible to prevent the occurrence of cracks and peeling.
Of course, except that the above-mentioned stress concentration portion is secured, the entire beam steel frame 2a is joined to the beam end portion 2b so as to be able to transmit stress as in the conventional case, so that the stress transmission performance required as the whole joint portion is obtained. Can be secured without hindrance.

  Note that, as shown in the example of the drawing, the thickness of the stress concentration portion (that is, the thickness of the insulating material 4) may be made uniform over the entire width dimension. However, as shown in FIG. The tip side may be made thinner gradually according to the stress distribution.

  Further, in the above embodiment, the stress concentration portion is provided only on the upper and lower sides of the beam steel frame 2a (the upper surface of the upper flange and the lower surface of the lower flange), but the stress concentration portion is set within a predetermined size range from the tip surface of the beam end portion 2b. As long as the position and range are arbitrary, for example, as shown in FIG. 3, it is set on the upper and lower surfaces of the upper and lower flanges, as shown in FIG. 4, only on the lower surface of the upper and lower flanges, As shown in FIG. 5, it may be set over the entire circumference of the beam steel frame 2a including the web.

  However, as in the conventional example shown in FIG. 11, cracks and peeling off at the tip surface of the beam end 2b are most likely to occur in the lower portion of the lower flange, so at least on the lower surface side of the lower flange as shown in FIG. Should be provided with an insulating material 4 to ensure insulation.

The above embodiment is an application example to the S-structured beam 2, but the embodiment shown in FIG. 7 is an application example to the S-structured pillar 3 as shown in FIG. In this case, the lower end portion of the column steel frame 3a as the steel frame member is embedded in the root winding concrete 3b as the RC member, but the stress concentration portion is set in a range of a predetermined dimension L from the upper surface of the root winding concrete 3b. By providing the insulating material 4 there, the column steel frame 3a and the root-wrapped concrete 3b are insulated so that stress cannot be transmitted, thereby preventing excessive stress concentration on the upper surface of the root-wrapped concrete 3b. It is intended to prevent peeling.
Also in this case, the insulating material 4 (stress concentration part) is provided on both outer surfaces of the left and right flanges of the column steel frame 3 as shown in FIG. Furthermore, as shown in FIG. 9, it may be provided over the entire circumference of the column steel frame 3a including the web.

Although the embodiment of the present invention has been described above, the present invention provides the case where the S-shaped beam 2 is joined to the RC column 1 as in the above-described embodiment, or the S-shaped column 3 is provided with the root-wrapped concrete 3a. Needless to say, the present invention can be widely applied not only to cases but also to cases where reinforced concrete members and steel members are joined.
Further, in the above embodiment, the steel member and the reinforced concrete member are insulated by interposing the insulating material 4 in the stress concentration portion. However, in the present invention, the edge is structurally cut so as to cut off the stress transmission in the stress concentration portion. The insulating material 4 is not necessarily provided as long as that is the case. For example, a similar insulating effect can be obtained by simply securing a gap corresponding to the thickness of the insulating material 4 in the stress concentration portion. can get.

1 Column 2 Beam 2a Beam steel frame (steel member)
2b Beam end (reinforced concrete member)
3 pillar 3a pillar steel frame (steel member)
3b Neck winding concrete (steel reinforced concrete member)
4 Insulation material (stress concentration part)

Claims (3)

It is a structure for embedding the ends of steel members in reinforced concrete members and joining these steel members and reinforced concrete members,
Of the embedded portion of the reinforced concrete member in which the steel member is embedded, a range of a predetermined dimension from the surface of the reinforced concrete member is defined as a stress concentrated portion, and the stress concentrated portion cannot transmit stress to the reinforced concrete member. The steel member and the reinforced concrete member, wherein the steel member and the reinforced concrete member are integrated so as to be able to transmit stress to the reinforced concrete member throughout the embedded portion and on the tip side of the stress concentration portion. Junction structure. A joint structure between the steel frame member and the reinforced concrete member according to claim 1,
A joining structure of a steel member and a reinforced concrete member, wherein an insulating material that insulates the reinforced concrete member and the steel member from each other so as not to transmit stress is provided in the stress concentration portion. A joint structure between the steel member and the reinforced concrete member according to claim 1 or 2,
A joining structure between a steel member and a reinforced concrete member, wherein the thickness of the stress concentration portion is gradually reduced from the surface of the reinforced concrete member toward the tip side.

Images