JP2011157797A - Aseismatic reinforcing construction method of reinforced concrete column - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a sufficient pulling yield strength of a reinforcing member arranged on the exposed surface of a column which is integral with a wall. <P>SOLUTION: In the aseismatic reinforcing construction method, reinforcing steel (60) is arranged on the exposed surface of the reinforced concrete column (10) which is integal with the wall, and is fixed on the wall (30) which is integral with the column by anchoring steel (80). The anchoring steel is arranged near the column so that a corn-shaped destruction area (A) by the pulling force of the anchoring steel can apply the column to be reinforced, and is buried into and fixed on the wall. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a seismic reinforcement method for reinforced concrete columns.

  The current seismic reinforcement of viaduct columns is in principle to reinforce the entire length and perimeter, but in RC ramen viaducts for railways in urban areas, viaducts are often used in stores and warehouses. It may be difficult to reinforce the entire length of the member. Conventionally, the seismic reinforcement work for RC structures in such places has been performed by the following method.

[Reinforcement of the entire surface by removing the obstacles and rolling up the steel sheet]
As shown in FIG. 4, when an obstacle 20 such as an outer wall is attached to the existing RC pillar 10, a part 21 of the obstacle 20 in contact with the pillar 10 is temporarily removed along the pillar, and the steel plate is wound. Reinforcement was performed over the entire length and the entire circumference by the vertical reinforcement method and the RC vertical reinforcement method. This reinforcement method often requires a great deal of labor, cost, and construction period for temporary removal and restoration of obstacles.
As shown in FIG. 5 (FIG. 5 (a) is a perspective view and FIG. 5 (b) is a cross-sectional view), the column 10 reinforced with the axial rebar 15 and the like is used as a method of construction. For example, it is not applicable to the case where there is earth and sand 35 on the back surface by integrating with the wall 30 such as a retaining wall, etc., and as shown in FIG. I can't do that either.

[One side seismic reinforcement method]
A one-surface seismic reinforcement method that can be constructed only from one exposed surface of pillar members in places under elevated use, etc. when full-scale reinforcement is difficult is implemented. For example, as shown in FIG. 7 (FIG. 7 (a) is a perspective view and FIG. 7 (b) is a cross-sectional view), for example, the pillar 10 is integrated with a wall 30 such as a retaining wall, and earth and sand 35 are formed on the back surface. In some cases, the exposed surface is drilled by core boring while avoiding the axial rebar 15, then the reinforcing steel bar 50 is inserted and the reinforcing steel plate 60 is attached, and a filler such as resin is injected into the gap between the steel plate and the column. Since this is a construction method that does not require removal and restoration of obstacles, costs may be reduced and construction periods may be shortened.
However, as shown in FIG. 8, when the axial reinforcing bar 15 of the reinforcement target column 10 has a plurality of stages (for example, two stages), the hole cannot be drilled so as not to interfere with the axial reinforcing bar 15 (FIG. ) And the reinforcing reinforcing bars 50 cannot be arranged. Moreover, even if it can be constructed, since drilling is very difficult, cost and construction time are required.

  As mentioned above, when reinforcing the pillar whose back side is integrated with the wall, it is possible to fix the reinforcing steel plate etc. by arranging the reinforcing steel plate etc. on the exposed surface and arranging the anchor reinforcement etc. in the integrated wall. Conceivable. For example, as shown in FIG. 9, when the pillar 10 is integrated with the wall 30 and there is earth and sand 35 on the back surface, the exposed three surfaces are surrounded by the reinforcing steel plate 60, and the end of the reinforcing steel plate is the surface of the integrated wall 30. It is possible to consider a construction method in which the bent portion is fixed with anchor steel material 70 such as an anchor bolt. However, the thickness of the wall integrated with the column is usually only about 300 mm, and the embedding depth L of the anchor steel material 70 does not reach 300 mm, and a necessary fixing length, for example, 12φ (φ: anchor steel material diameter) is ensured. It is not possible to obtain sufficient pulling strength.

The present invention is intended to solve the above-mentioned problems, and by arranging a reinforcing material on an exposed surface of a pillar integrated with a wall and installing an anchor steel material on the wall, sufficient pulling strength can be ensured. The purpose is to do.
In the seismic reinforcement method in which a reinforcing steel material is disposed on an exposed surface of a reinforced concrete column integrated with a wall and anchored to the wall integrated with the column by an anchor steel material, the anchor steel material is disposed close to the column and the anchor steel material is It is characterized in that the cone-shaped fracture area due to pull-out force is applied to the pillar to be reinforced and is embedded and fixed in the wall.
Further, the present invention is characterized in that the reinforcing steel material is also used as an anchor steel material, and the tip portion thereof is embedded and fixed in a wall integrated with a column.
Further, the present invention is characterized in that concrete is cast around the reinforcing steel material.

  The present invention secures sufficient pulling strength by placing a reinforcing material on the exposed surface of the pillar integrated with the wall and installing the anchor steel material in the vicinity of the pillar so that the cone-shaped fracture range is applied to the pillar. Is possible.

It is a figure explaining the earthquake-proof reinforcement construction method of this invention. It is a figure explaining the other example of the earthquake-proof reinforcement method of this invention. It is a figure explaining the other example of the earthquake-proof reinforcement method of this invention. It is a figure explaining the conventional reinforcement construction method which removes a part of obstacle. It is a figure explaining the pillar where the back was integrated with the pillar. It is a figure explaining the example which the back in which four-surface reinforcement is difficult was integrated with the pillar. It is a figure explaining the conventional one surface seismic reinforcement construction method. It is a figure explaining the conventional one surface seismic reinforcement construction method. It is a figure explaining the conventional three-surface seismic reinforcement construction method.

Embodiments of the present invention will be described below.
FIG. 1 is a diagram for explaining an example of the seismic reinforcement method according to the present invention. FIG. 1 (a) is a perspective view, and FIG. 1 (b) and FIG. 1 (c) are cross-sectional views.
In this example, the column 10 in which the axial reinforcing bars 15 are arranged in two stages is integrated with a wall 30 such as a retaining wall and a horizontal reinforcing bar or the like, and there is earth and sand 35 on the back surface, and the wall 30 is concrete. There may be water on the back of the wall. The exposed three surfaces of the column 10 are surrounded by a reinforcing material 60 such as a reinforcing steel plate, the end of the reinforcing material is bent along the wall 30, and the bent portion is columned by an anchor steel member 80 such as an anchor reinforcing bar or an anchor bolt. Are fixed at a plurality of locations along the height direction (FIG. 1A). A filler such as mortar or resin is injected between the reinforcing member 60 and the column 10. As described above, since the thickness of the wall 30 integrated with the pillar is only about 300 mm, a necessary fixing length cannot be obtained. Therefore, the anchor steel material 80 is installed in the vicinity of the column so that the cone-shaped fracture range A when the pulling force is applied is applied to the column 10 to be reinforced (FIG. 1B). When a strong pulling force is applied to the anchor steel material 80, the cone-shaped fracture is in a conical range of 45 ° from the end of the head portion of the anchor steel material. Therefore, the distance D from the column surface of the anchor steel material is It is necessary to make it smaller than the length embedded in the wall 30. As shown in FIG.1 (c), when the distance D from the pillar of the anchor steel material 80 is large, since the cone-shaped fracture range A does not cover a pillar, it cannot improve a pulling-out yield strength. In addition, since the wall 30 integrated with the column uses fewer rebars than the column 10, installation of the anchor steel material is easy. Thus, the pulling strength of the anchor steel material can be improved by taking the reaction force from the wall integrated with the column and applying the cone-shaped fracture range to the column to be reinforced. In the above description, the case where the three pillar surfaces are exposed has been described, but the present invention can be similarly applied to the case where two surfaces are exposed.

2A and 2B are diagrams for explaining another example of the seismic reinforcement method of the present invention. FIG. 2A is a perspective view and FIG. 2B is a cross-sectional view.
The pillar 10 is integrated with a wall 30 such as a retaining wall with a lateral reinforcing bar or the like, and the earth and sand 35 are provided on the back surface thereof, as in the case of FIG. In this example, the pillar 10 is surrounded by an anchor steel material 85 such as an anchor reinforcing bar at a predetermined interval, and the tip end portion of the anchor steel material 85 is embedded in the integrated wall 30 and directly fixed. The anchor steel material 85 restrains the column 10 via the corner support material 87. Also in this example, the drawing strength of the anchor steel material can be improved by making the distance between the anchoring position of the anchor steel material 85 and the column close to each other so that the cone-shaped fracture range A is applied to the column 10.

3A and 3B are diagrams for explaining another example of the seismic reinforcement method of the present invention. FIG. 3A is a perspective view, and FIG. 3B is a cross-sectional view.
In this example, the reinforcing bars 88 are interposed at the corners of the anchor steel material 85 and the column 10, and the concrete 90 is placed so as to wrap the anchor steel material 85 to restrain the column 10. As in the case of FIG. 2, the anchoring strength of the anchor steel material 85 can be improved by bringing the anchoring position of the anchor steel material 85 close to the column so that the cone-shaped fracture range A is applied to the column 10.

DESCRIPTION OF SYMBOLS 10 ... Column, 15 ... Axial reinforcing bar, 30 ... Earth retaining wall, 35 ... Earth and sand, 60 ... Reinforced steel plate, 80 ... Anchor steel material, A ... Cone-like fracture range.

Claims (3)

In the seismic strengthening method in which reinforcing steel is placed on the exposed surface of the reinforced concrete column integrated with the wall and anchored to the wall integrated with the column by anchor steel,
A seismic reinforcement method for reinforced concrete columns, in which anchor steel is placed close to the column so that the cone-shaped fracture area due to the pulling force of the anchor steel is applied to the column to be reinforced and embedded in the wall. 2. The method for seismic reinforcement of a reinforced concrete column according to claim 1, wherein the reinforcing steel material is also used as an anchor steel material, and its tip portion is embedded and fixed in a wall integrated with the column. The seismic reinforcement method for a reinforced concrete column according to claim 2, wherein concrete is cast around the reinforcing steel material.

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