JP5043768B2 - Column beam structure with semi-rigid joint at beam end - Google Patents

Description

  The present invention relates to a column beam structure of a building, and more specifically, has a column beam integrated with a column only in a part of the beam cross section, hereinafter referred to as a “semi-rigid joint column beam”. This relates to a column beam structure that reduces the moment applied to the column during an earthquake.

  PCI joint design handbook for precast and prestressed concrete, 6th edition, 2004 as a joint system for pin-supporting both ends of a beam to a so-called rigid joint column beam that joins the column in the entire cross section of the beam (non-patent document 1) ) Shows the structure shown in FIG. In this structure, the vicinity of the lower end of the beam end portion is cut out to form an end portion in a staircase shape, and a support protrusion (corbel) 10 is provided on the column 18. The lower surface 12 is supported. A bearing pad 14 may be interposed between the support protrusion 10 and the lower surface 12 of the end portion of the beam supported by the support protrusion 10. In the case of this structure, the beam 16 is pin-supported at both ends thereof, but the strength of the joint portion related to the transmission of the horizontal load is defined by the frictional force between the contact surfaces or the shear strength of the bearing pad 14. For this reason, there is a problem in the transmission of the horizontal force when a large horizontal force acts as in an earthquake.

Japanese Examined Patent Publication No. 5-14061 (Patent Document 1) discloses a column beam connection shown in FIG. According to the structure disclosed in the above publication, the vicinity of the lower end of the beam end portion is cut out to form the end portion in a staircase shape, and a support projection (support bracket) 10 is provided on the column. The lower surface 22 of the stepped end 20 of the beam 16 is supported. A base mortar 24 is interposed between the support protrusion 10 and the lower surface 22 of the end portion 20 of the beam supported by the support protrusion 10, and a reinforcing bar 28 is provided on the lower surface of the stepped end portion of the support protrusion 10 and the beam. The column beams are connected through 22. In the case of the structure, since the strength of the joint relating to the transmission of the horizontal load is defined by the strength of the base mortar 24 or the reinforcing bar 28, the transmission of the horizontal force when a large horizontal force acts as in an earthquake. The point which has a subject in is the same as that of the structure described in the nonpatent literature 1 mentioned above.
PCI Design Handbook, 6th Edition, 2004 Japanese Patent Publication No. 5-14061

  The present invention aims to solve the above-mentioned problems of the prior art, and reduces the bending moment acting on the column by pin-joining the column beam joint, and at the same time, seismic force from the beam to the column. It is an object of the present invention to provide a column beam structure capable of reliably transmitting a horizontal force such as the above.

In order to achieve the above object, the present invention proposes a column beam structure of a building having a beam integrated with a column only at a part of the beam. Specifically, for example, a through-column having a bracket on the side surface and a beam having a step in the end cross section, a column beam structure joined with a gap therebetween,
The beam is constructed on the bracket via a deformable member, and only a part of the cross section is in contact with the side surface of the column, and is integrated by a fixing material that intersects the contacted surface. It is a column beam structure.

  A beam integrated with a column only in a part of the beam cross section refers to a state in which only a certain range of the beam is integrally coupled with the column, and a beam whose end is formed in a step shape, It can be realized by a beam in which a slit is formed at the end, a beam in which the cross-sectional area in the vicinity of the end is gradually reduced toward the joint with the column, and the like. Here, the term “integrated” refers to a state in which the concrete of the column beam is integrally formed, and the reinforcing bar penetrates the column beam joint surface. Therefore, the structures described in Non-Patent Document 1 and Patent Document 1 do not correspond to a beam integrated with a column only at least in a part of the beam cross section. The gap between the through pillar and the beam is preferably between the side surface of the bracket and the lower cross-section of the beam. The fixing material that intersects the contact surface is, for example, a main reinforcing bar or a tension member of a beam that passes through a cross section of the beam that contacts the column side surface and is fixed to the column or the beam on the opposite side.

  The column beam structure according to the present invention may further include a support member or a deformable member that transmits a vertical load between the column beams, in addition to the portion where the column beams are integrated. It is preferable that the support member (deformation member) does not restrain the rotation of the beam end with respect to the column (the rigidity against rotation is small). For example, it is an elastic member, an elastic-plastic member, or the like. According to such a structure, it is not necessary to bear all the vertical loads acting on the beam by the shearing force at the end of the beam, so that there is a margin in the cross-sectional design of the beam. The deformable member is preferably deformable in the horizontal direction. Moreover, it is preferable that a deformation | transformation member is comprised by either an elastic body, a viscous body, a viscoelastic body, a friction material, and a sliding material.

  The supporting member that transmits the vertical load between the column beams may be a receiving side bracket provided on the column so as to protrude toward the beam side and a hanging side bracket provided on the beam end. The receiving bracket refers to a portion protruding in the direction of the beam from the side surface of the column, and does not depend on the shape size. The hanging bracket refers to the vicinity of the tip of the beam end formed in a staircase shape. In addition, the connection of the column beam according to the present invention is not limited to the one via the bracket as described above, but a structure in which a part of the beam end portion penetrates the column, and the beam end portion is not formed in a step shape. A structure in which the beam end is supported from below by a bracket on the receiving side of the column can also be employed simply by providing a slit.

  Between the receiving bracket and the hanging bracket, a support member that supports a vertical load and allows deformation in the horizontal direction may be interposed. When the support member allows deformation in the horizontal direction, the vertical load of the beam can be effectively transmitted to the column, and at the same time, the rotational restraint force on the column at the end of the beam can be weakened. As the bearing member, it is preferable to use any one of a sliding bearing, a viscoelastic body, a laminated rubber, and a friction material.

  According to the present invention, the bending moment acting on the column can be reduced, and the cross-sectional area of the column can be reduced. For example, by adopting a flat column by reducing the cross section in the out-of-plane direction of the column by the method of the present invention, it is possible to realize an easy-to-use space without (or small) protruding into the living room.

  Furthermore, it is also possible to improve the vibration characteristics of the building by using the bending resistance generated at the beam end or the above-mentioned support member as a damping element when the building vibrates.

  Specific embodiments of the present invention will be described below on the basis of examples. However, the examples are only described to help the understanding of the invention, and therefore the present invention is not limited to the examples described below. Needless to say, it is not limited.

FIG. 3 is a conceptual diagram showing a column beam semi-rigid joint according to the present invention.
As shown in FIG. 3, a beam 3 having a hook-side bracket 4 having a shape paired with the receiving-side bracket 2 protruding from the column 1 is placed. The receiving side bracket 2 and the hanging side bracket 4 transmit a load in the vertical direction and can be relatively displaced in the horizontal direction. In the vicinity of the upper end of the beam 3, a fixing material 7 such as a reinforcing bar penetrates the column beam and is fixed to the column 1 side. Further, the column 1 and the beam 3 are integrated only at an integrated portion 8 with the column located in the vicinity of the upper end of the beam 3, and the other portions are completely separated by the slit 6. However, a support member (deformable member) 5 is placed on the receiving bracket 2 to support the hanging bracket 4 of the beam 3 in order to transmit the vertical load.

  When a moment acts on the beam end, the support member 5 is deformed in the horizontal direction within the clearance of the slit 6, thereby causing rotational deformation at the beam end with the vicinity of the fixing position of the fixing material 7 as the rotation center. . The bending moment generated at the beam end is mainly the product of the vertical distance L between the fixing member 7 and the support member 5 and the horizontal force applied to the support member 5, but the horizontal force generated at the support member 5 is kept low. It is possible to reduce the bending moment at the end of the beam and consequently reduce the cross-sectional area of the column 1 connected to the beam.

  On the other hand, the transmission of the horizontal force from the beam to the column depends on the axial force acting on the integrated portion 8 of the beam 3 and the column 1 and the fixing material 7 and the shearing force acting on the support member 5. By adjusting the cross-sectional area of the integrated portion 8, the cross-sectional area necessary for transmitting horizontal force such as seismic force can be ensured. As the support member 5, not only an elastic body but also a viscous body, a viscoelastic body, a plasticizing member, a friction member, a laminated rubber, or the like can be used.

  In the above embodiment, it is assumed that the receiving side bracket 2 and the hanging side bracket 4 are provided to support the vertical load acting on the beam 3, but depending on the load condition, the column and the beam may be provided without providing the bracket. It is also possible to integrate only at the beam end integrated portion 8 and to separate a portion other than the beam cross-section integrated portion 8 from the pillar by a slit. In this case, the cross section of the beam may gradually decrease as it approaches the integrated portion 8. Alternatively, a configuration is possible in which a portion other than the integrated portion 8 is separated by a slit, and the hanging bracket 4 is not provided and the lower end of the beam 3 is supported by the receiving bracket 2. The receiving bracket 2 may directly support the lower end of the integrated portion 8 of the beam 3.

Example of structure where beam end is supported by bearing pad (conventional technology) Example of structure in which beam ends are supported by brackets and brackets are connected by reinforcing bars (conventional technology) Conceptual diagram of column beam frame based on the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 18 Pillar 2, 10 Receiving side brackets 3, 16 Beam 4 Hanging side bracket 5 Support member 6 Slit 7 Fixing material 8 Integrated part L Vertical distance of fixing material and support member

Claims (4)

A through-column having a bracket on the side surface and a beam having a step in the end cross section, a column beam structure joined with a gap therebetween,
The beam is installed on the bracket via a deformable member, and only a part of the cross section of the end portion is in contact with the column side surface, and is integrated by a fixing material that intersects the contacted surface. Column beam structure characterized by.   The column beam structure according to claim 1, wherein the deformable member is deformable in a horizontal direction.   3. The column beam structure according to claim 1, wherein the deformable member is formed of any one of an elastic body, a viscous body, a viscoelastic body, a friction material, and a sliding material.   The column beam structure according to claim 1, wherein the gap is between a side surface of the bracket and a lower section of the beam.

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