JP2013083063A - Method for reinforcing existing mullion wall of reinforcement concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reinforcing an existing nonbearing mullion wall made of reinforcement concrete, which prevents the occurrence of fissures, cracks, and exfoliation of concrete caused by earthquake or the like, with a simple construction.SOLUTION: The finishing material of a nonbearing mullion wall 2 of an existing reinforcement concrete structure is hacked from the surface 2a by a predetermined thickness. A reinforcement frame 10 for shear reinforcement composed of two or more vertical reinforcement bars 10a arranged at predetermined intervals across which lateral reinforcement bars are bridged at a fixed intervals so as to be spot-welded is temporarily tacked to the exposed hacked surface 2b of the mullion wall 2. The hacked surface 2b of the hacked mullion wall 2A is applied with a polymer cement mortar 11 by a thickness to cover the reinforcement frame 10 for shear reinforcement.

Description

  The present invention relates to a method for reinforcing a reinforced concrete standing wall installed as a non-bearing wall in a reinforced concrete apartment house or the like.

  Conventionally, as a reinforcing method for a structural frame made of reinforced concrete, a method in which sheet-like continuous fibers are pasted or concrete is beaten is proposed. However, in such a reinforcing method, the anchor material is mainly used in order to exert the joining force between the reinforcing portion and the existing portion. Therefore, it takes time and effort to drive the anchor material, noise is generated, and the reinforcement is not much. There is a problem that the effect does not increase.

  The inventor of the present invention proposes a method for reinforcing an existing cloth foundation by post-construction in Patent Document 1 without damaging the cloth base with an anchor material or the like. In the reinforcing method of Patent Document 1, an assembly in which a plurality of vertical reinforcing bars (additional reinforcing bars) are arranged and connected by crosspieces, or a reinforcing member such as a grid made of FRP is attached to the rising portion of the cloth foundation. The polymer cement mortar is applied to the side. As a result, it is possible to increase the thickness of the rising portion and widen the foundation width, and it is possible to join the vertical streaks, the grid made of FRP and the like to the existing foundation by the adhesive force of the polymer cement mortar. Therefore, the shear strength can be easily increased without impairing the strength of the existing foundation.

  However, in the reinforcing method of Patent Document 1, the additional reinforcing bars are attached only in the direction of the shearing force of the cloth foundation, and the crosspiece is a positioning material for the additional reinforcing bars and bears the load in the bending direction on the cloth foundation. In some cases, the bending strength of the fabric foundation cannot be increased sufficiently. In addition, the FRP lattice has high toughness, so that the fabric foundation can be prevented from collapsing or damaging. However, since the reinforcing member is joined to the fabric foundation only by the adhesive force of the polymer cement mortar, shear reinforcement In order to exhibit the effect sufficiently, it has been desired to further increase the bonding force.

  Therefore, the present inventor in Patent Document 2, a simple reinforcing method that can reinforce an existing reinforced concrete structure such as a cloth foundation or a solid foundation in a building by post-construction to increase shear strength, and A structural frame reinforced by a reinforcement method is proposed.

JP 2006-233671 A JP 2009-185549 A

  Conventionally, proposals have been made to increase the seismic strength of existing structural members such as foundations, beams and columns in reinforced concrete structures as described above. However, no attention has been paid to the reinforcement of non-bearing walls, particularly vertical walls, in reinforced concrete structures, and no reinforcement method has been proposed.

  The vertical wall has an edge or a slit (including a complete slit and a partial slit) formed between the columns made of reinforced concrete arranged on both sides. In addition, the single reinforcement arranged inside does not have sufficient fixing length for the left and right reinforced concrete columns and the upper and lower reinforced concrete beams, or the edges are cut by slits etc. ing. Therefore, the vertical wall is a non-bearing wall that is not considered as a bearing wall in the structural calculation.

  For this reason, when a large external force is applied due to an earthquake or the like, and a reinforced concrete building is deformed, the vertical wall is forcibly sheared, a large shear crack is generated in the vertical wall, the vertical wall is destroyed and the concrete is peeled off. There is a danger such as.

  In view of this point, the problem of the present invention is that a reinforced concrete vertical wall that is an existing non-bearing wall can be shear reinforced by simple construction so that cracks, cracks, peeling of concrete, etc. do not occur due to earthquakes, etc. Is to propose.

In order to solve the above problems, the present invention is a method for reinforcing a reinforced concrete vertical wall that is a non-bearing wall in an existing reinforced concrete structure,
A finishing material winding step of rolling a finishing material of the vertical wall at a predetermined thickness from at least one surface of the vertical wall;
A reinforcing bar frame for shear reinforcement, in which two or more longitudinal bars arranged at a predetermined interval are spot-welded at regular intervals to the vertical surface of the vertical wall. A shear reinforcing bar frame temporary fixing step for temporarily fixing,
Integrated shear reinforcement reinforcing bar frame with a thickness that can cover the reinforcing steel frame for shear reinforcement, and by applying polymer cement mortar to the surface of the vertical wall to integrate the reinforcing steel frame for shear reinforcement into the vertical wall And a process.

  Here, since the thickness of the vertical wall is generally 100 mm to 120 mm, a finishing material (tile, paint, mortar, etc.) on the surface of the vertical wall is wound, and the diameter of the horizontal wall for shear reinforcement is 10 mm to What is necessary is just to attach a reinforcing bar frame for shear reinforcement in which deformed steel bars of 16 mm are arranged at intervals of 200 mm, for example, to the turning surface. In addition, the condition that the reinforcing bars to be post-constructed in this way must be fixed to the surrounding structural members is not necessary. That is, although fixing is basically unnecessary, it may be fixed appropriately, and the present invention is not intended to exclude such a case.

  According to the method of the present invention, the existing single-reinforced reinforced concrete standing wall can be made into a double-reinforced wall body by extremely simple construction. By attaching a reinforcing steel frame for shear reinforcement, the reinforcing steel frame for shear reinforcement (mainly transverse bars) takes charge of the shearing force acting on the vertical wall due to an earthquake, etc., so that cracks and cracks can easily occur in concrete. It can also prevent concrete peeling. Therefore, it is possible to avoid or reduce the risk that the vertical wall is destroyed by an earthquake or the like and the resident is injured.

(A) is a front view which shows an example of the existing reinforced concrete standing wall in a reinforced concrete structure, (b) is the sectional drawing. (A)-(d) is explanatory drawing which shows an example of the reinforcement method of the vertical wall by this invention. (A) is a front view which shows the vertical wall after reinforcement, (b) is a front view which shows the reinforcing steel frame for shear reinforcement. (A) And (b) is explanatory drawing which shows two examples of the connection of a beam and a vertical wall. (A) And (b) is explanatory drawing which shows two examples of the reinforcing steel frame for shear reinforcement.

  Hereinafter, an embodiment of a method for reinforcing an existing vertical wall to which the present invention is applied will be described with reference to the drawings.

  First, with reference to FIG. 1 (a), (b), an example of the concrete standing wall of the reinforcement object is demonstrated. In a reinforced concrete structure 1, for example, a reinforced concrete apartment house, a reinforced concrete vertical wall 2 may be installed as a partition wall in each dwelling unit or the like. The reinforced concrete standing wall 2 is in a state where the edges are completely cut by the openings 5 and 6 from the columns 3 and 4 between the columns 3 and 4 of the reinforced concrete. Further, although it is connected to the upper reinforced concrete beam 7, half of the thickness direction is connected to the lower reinforced concrete beam 8 with the edge cut by the slit 9. Therefore, it is a non-bearing wall that is ignored in structural calculations.

  Here, the connection between the beam 7 and the vertical wall 2 is the case shown in FIG. 1 (b), the concentric connection shown in FIG. 4 (a), and the right side surface of the beam 7 as shown in FIG. 4 (b). Of course, the present invention is not limited to that shown in FIG. 1B. Moreover, in the standing wall 2 shown in FIG. 1, the slit 9 is formed along the lower edge, but it goes without saying that the present invention can be similarly applied to a standing wall without the slit 9. In particular, in the case of a wall having a thickness of 100 mm or less, there is often no slit. Therefore, the vertical wall does not require the necessity of a slit.

  Next, an example of a shear reinforcement method for the vertical wall 2 will be described with reference to FIG. First, the existing standing wall 2 shown in FIG. 2A is a wall having a thickness of about 120 mm including a finishing material including mortar for surface finishing, for example. As shown in FIG. 2B, the finishing material is removed over the entire surface 1a of the vertical wall 2 (finishing material winding step).

  Here, as shown in FIG. 3B, a shear reinforcing reinforcing bar frame 10 is prepared in advance by factory production or the like. The reinforcing steel frame 10 for shear reinforcement has a configuration in which, for example, deformed steel bars having a diameter of 13 mm are used as the vertical bars 10a and the horizontal bars 10b, and are joined by spot welding in a grid pattern at intervals of 200 mm, for example. Further, the reinforcing steel frame 10 for shear reinforcement has a rectangular outline shape that is slightly smaller than the rectangular outline shape of the surface 2a of the standing wall 2 to be reinforced. It is also possible to use a reinforcing bar frame for shear reinforcement formed by joining deformed steel bars having different diameters in a grid pattern at different pitches. Also, the arrangement pitch of the vertical and horizontal reinforcing bars can be different, and the diameters of the vertical and horizontal reinforcing bars can be different.

  Further, the reinforcing steel frame 10 for shear reinforcement is not limited to the one shown in FIG. 3B, and various configurations can be used. 5 (a) and 5 (b) show two typical examples of shear reinforcing reinforcing bar frames. In the shear reinforcing reinforcing bar frame 10A shown in FIG. 5A, one vertical bar 10a is arranged on each side, and the horizontal bars 10b are bridged at equal intervals between them. In the reinforcing bar frame 10B for shear reinforcement shown in FIG. 5B, two vertical bars 10a are arranged on both sides, and the horizontal bars 10b are bridged at equal intervals between them.

  Referring back to FIG. 2 again, after the finishing material of the vertical wall 2 is scraped, the shear reinforcing reinforcing bar frame 10 is placed on the vertical surface 2b of the vertical wall 2 as shown in FIG. Position and temporarily fix using a metal fitting or the like (shear reinforcement reinforcing bar frame temporary fixing process). Thereafter, as shown in FIGS. 2 (d) and 3 (a), the polymer cement mortar 11 is applied so as to cover the turning surface 2 b and the shear reinforcing reinforcing bar frame 10. The coating thickness of the polymer cement mortar 11 may be, for example, 40 mm or more and the existing standing wall thickness or less. Thereafter, the polymer cement mortar 11 is cured and hardened, and the shear reinforcing reinforcing bar frame 10 is integrated with the vertical wall 2 (shear reinforcing reinforcing bar frame integrating step). The condition that the shear reinforcing reinforcing bar frame 10 has to be fixed to the surrounding structural member is not necessary, but may be appropriately fixed depending on the case, and the present invention excludes such a case. It is not intended to be.

  The vertical wall 2 after being reinforced in this manner becomes a double-reinforced reinforced concrete vertical wall 2A. Due to the high adhesive force of the polymer cement mortar 11, the reinforcing steel frame 10 for shear reinforcement is firmly integrated with the existing vertical wall portion. Therefore, when an external force is applied due to an earthquake or the like, the reinforcing reinforcing steel frame 10 withstands the shearing force acting on the vertical wall 2A, so that the concrete part of the vertical wall 2A is cracked, cracked, and the like is peeled off. The risk of doing so can be prevented.

  The reinforcing bars used for the shear reinforcing reinforcing bar frame 10 are assembly bars quality controlled so as to have a strength higher than the standard value defined in JIS or the like, and are formed of a steel material such as SD295A or SD345. For example, reinforcing bars such as D10, D13, and D16 are used as the vertical and horizontal bars.

The polymer cement mortar 11 is a known one in which an epoxy resin or the like is mixed with Portland cement. For example, by blending a polymer cement mortar 11 using a cement admixture polymer compatible with JIS A6203 (cement admixture polymer dispersion and re-emulsifying powder resin) or a polymer having a quality equivalent to or higher than that, High durability and high adhesion polymer cement with strength of 6N / mm ² or higher, compressive strength of 20N / mm ² or higher, adhesive strength of 1N / mm ² or higher, and adhesive durability of 1N / mm ² or higher. Mortar 11 is obtained. In addition, a rust preventive agent, an early strengthening agent, an early hardening agent, or the like may be mixed into the polymer cement mortar 11 to improve workability and durability.

1 ・ ・ Reinforced concrete structure 2 ・ Standing wall 2A ・ ・ Standing wall 2a after reinforcement ・ ・ Surface 2b ・ ・ Surface 3, 4 ・ ・ Columns 5 and 6 ・ ・ Openings 7 and 8 ・ ・ Beam 9 ・・ Slit 10, 10A, 10B ・ ・ Reinforcing bar frame 10a ・ ・ Vertical bar 10b ・ ・ Horizontal bar 11 ・ ・ Polymer cement mortar

Claims (3)

A method of reinforcing a reinforced concrete vertical wall, which is a non-bearing wall in an existing reinforced concrete structure,
A finishing material winding step of rolling a finishing material of the vertical wall from at least one surface of the vertical wall;
Shear reinforcement for temporarily fixing a reinforcing bar frame for shear reinforcement in which transverse bars are spot-welded at fixed intervals to two or three or more vertical bars arranged at predetermined intervals on the surface of the vertical wall. Rebar frame temporary fixing process,
Reinforcement frame for shear reinforcement in which the shear reinforcement reinforcing bar frame is integrated with the vertical wall by applying a polymer cement mortar to the surface of the vertical wall with a thickness that can cover the shear reinforcement reinforcing bar frame A method for reinforcing an existing standing wall, comprising an integration step. In claim 1,
The vertical wall has a thickness of 100 mm to 120 mm,
In the finishing material winding step, the finishing material on the surface of the vertical wall is rolled with a thickness of 30 mm to 40 mm. In claim 1 or 2,
The method for reinforcing an existing standing wall, wherein the shear reinforcing reinforcing bar frame is any one of the following (a), (b), and (c).
(A) As vertical bars and horizontal bars, deformed steel bars having a diameter of 13 mm to 16 mm are assembled in a vertical and horizontal manner at intervals of 200 mm and spot-welded. (B) As vertical bars, deformed steel bars having a diameter of 13 mm to 16 mm are predetermined. One bar is arranged on both sides at intervals, and between these, deformed steel bars having a diameter of 13 mm to 16 mm are spanned and spot-welded as horizontal bars (c) As vertical bars, the diameter is Two deformed steel bars of 13 mm to 16 mm are arranged on both sides at a predetermined interval, and a deformed steel bar having a diameter of 13 mm to 16 mm is spanned at a predetermined interval and spot welded between them as a horizontal bar.

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