JPH11107542A - Reinforcing method for existing concrete building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reinforcing a concrete building at low noise and preferably at low vibration. SOLUTION: To reinforce a concrete building 10, first a plurality of openings that open to the surface of a mortar layer 20 covering the skeleton 12 of the building are provided through the mortar layer 20 and are filled with an expanding agent, and the mortar layer 20 is separated from the skeleton 12 by the cubic expansion of the expanding agent. Next, a plurality of holes 26 that open to the surface of the skeleton 12 are bored, and anchor bolts are driven into the holes 26. Next, braces are secured to the skeleton 12 via the anchor bolts. The openings and the holes 26 are preferably formed by ultrasonic cutting. The holes 26 may be bored by ultrasonic cutting through the mortar layer 20, and if the skeleton 12 has no mortar layer 20, the holes 26 are bored in a concrete part by ultrasonic cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for reinforcing an existing or existing concrete building.

[0002]

2. Description of the Related Art A brace is attached to an existing concrete building for its seismic reinforcement.

Conventionally, the mounting of the brace is performed by providing a plurality of holes on the surface of the body, opening anchor bolts in each of the holes, and then fixing the brace to the anchor bolts with nuts. . If the concrete surface of the skeleton is covered with a mortar layer for the purpose of adjusting its unevenness, finishing, etc., the mortar layer is peeled off, if necessary, before forming the holes.

[0004]

The piercing of the skeleton is performed using, for example, a drill, and the mortar layer is peeled off by crushing the mortar layer with, for example, a breaker. However, the work of perforating the skeleton involves noise, and the work of peeling the mortar layer involves generation of large noise or vibration. This may cause physical and mental distress to residents and users of the building in service, and may have a significant adverse effect on the operation or operation of the facilities and equipment within the building. In particular, hotels,
This is remarkable in buildings such as hospitals. For this reason, in the above-mentioned conventional reinforcing method, the working time is limited, or there are cases where it is practically impossible to perform the work.

It is an object of the present invention to provide a method for reinforcing a concrete building with low noise, preferably even low vibration.

[0006]

In order to reinforce a concrete building, first, a plurality of holes are opened in the body by ultrasonic cutting, and anchor bolts are implanted in each hole. A brace is fixed to the frame via the anchor bolt. The surface of the skeleton is defined by exposed concrete or a mortar layer as a finish.

When the surface of the skeleton is defined by the mortar layer, preferably, the mortar layer is provided with a plurality of openings which are open to the surface, each opening is filled with an expanding agent, and the volume of the expanding agent is increased. The mortar layer is separated from the skeleton by expansion. Thereafter, a plurality of holes are opened, preferably by ultrasonic cutting, to be opened in the concrete surface of the skeleton, which appeared due to the peeling of the mortar layer, and anchor bolts are implanted in each hole. Next, a brace is fixed to the skeleton via the anchor bolt.

[0008]

According to the present invention, since perforation of the skeleton for implanting the anchor bolt is performed by ultrasonic cutting, noise and vibration hardly occur. In addition, regarding the peeling of the mortar layer of the skeleton, the volume expansion of the expanding agent filling each opening formed in the mortar layer progresses with time, and during this time, the expansion pressure is in a direction perpendicular to the peripheral wall surface of the opening. And thereby, the mortar layer is lifted between the holes, and a crack is generated in the mortar layer. This proceeds gently and with little vibration, so that the mortar layer peels off from the building. For these reasons, the building can be reinforced under low noise and low vibration. Further, if the openings in the mortar layer are formed by ultrasonic cutting, an even more quiet reinforcing work can be performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown an existing or existing concrete building 10 to which the reinforcing method according to the present invention is applied. The building 10 includes a concrete skeleton, that is, a pair of columns 12 facing each other,
It includes a plurality of walls 14, a plurality of beams 16, and the like.

[0010] In the illustrated example, the building 10 is reinforced.
In accordance with the present invention, braces 18 are attached to both pillars 12, which are one example of the frame. Needless to say, Pillar 1
2 instead of other skeletons, for example, beams between upper and lower floors, walls 14
The brace 18 can be attached to the like.

[0011] The mortar layer 20 covering the concrete surface is used for adjusting and finishing the unevenness of the concrete surface.
And the surface of the skeleton is defined by the mortar layer. The mortar layer 20 has an average thickness dimension of about 30 mm.

In order to attach the brace 18 to both columns 12, first, a part of the mortar layer 20 from each column 12, that is, in the illustrated example in which the column 12 has a rectangular cross section,
The mortar layer 20 on one of the four vertical surfaces of the pillar 12 to which the brace 18 is attached is peeled off. More specifically, the mortar layer 20 in the range from the height position of the floor surface of the floor slab 22 to the height position immediately below the beam 16 on the one vertical surface is peeled off.

Some mortar layers (hereinafter referred to as "mortar layers")
In this case, unless otherwise specified, it means “a part of the mortar layer”. First, a plurality of openings (not shown) are provided in the mortar layer 20 for opening the surface of the mortar layer 20.

The opening has a form such as a through-hole penetrating the mortar layer 20, a hole extending the mortar layer 20 over most of its thickness, a groove extending vertically and horizontally, and the like. The arrangement of the through holes and the arrangement of the holes may be regular or irregular, respectively. Further, the through holes and the holes may be mixed, or through holes or holes having different diameters may be mixed. Further, the through-hole and the hole may be in any direction regardless of the extension direction. That is, these axes may be either horizontal or non-horizontal, or they may be orthogonal or non-orthogonal to the surface of the column 12.

The openings can be formed by subjecting the mortar layer 20 to ultrasonic cutting. That is, a spindle (not shown) having a tip portion provided with a grindstone or a wheel (not shown) having a peripheral surface provided with a grindstone is rotated around each axis to reduce the cutting force of the grindstone. It can be formed by ultrasonically oscillating the spindle and the wheel, respectively, on the layer 20 and during this.

The direction in which the ultrasonic vibration is applied is the axial direction of the spindle and the radial direction of the wheel. The frequency and amplitude of the ultrasonic wave at this time are, for example, 20 kHz and 55 kHz, respectively.
Set to μm. By applying the ultrasonic vibration, the cutting resistance of the whetstone is significantly reduced. For this reason, the noise level and the vibration generated at the time of forming the opening can be significantly reduced, and more specifically, the noise or the cutting noise can be inaudible and almost non-vibration at a distance of several meters.

As a specific device for forming the opening, for example, a "hand-held rotary tool" described in Utility Model Registration No. 3019063 can be used. In this tool, a horn is attached to the tip of an ultrasonic vibrator that is rotatably supported in an outer case,
Further, a grindstone is attached to the tip of the horn. When the ultrasonic vibrator is driven to rotate around its axis, the horn and the grindstone rotate around these axes. By operating the ultrasonic vibrator, ultrasonic vibration can be generated in the axial direction of the horn. By pressing the whetstone against the surface of the column 12 and rotating the whetstone and applying ultrasonic vibration to the whetstone, almost no noise and vibration is generated,
The opening can be formed.

Regarding the openings, the shape, direction, and mutual distance of the openings are considered in consideration of the range or distance limit to which the inflation pressure of the inflating agent can be effectively applied, that is, the range or distance limit at which cracks can occur. The interval, size, depth, etc. can be set.

The opening can be formed by, for example, a cutting process using a drill on which ultrasonic vibration is not superimposed. However, the level of generated noise and vibration is higher in the case of cutting with the drill than in the case of ultrasonic cutting.

Next, each opening thus formed is filled with an expanding agent (not shown). The swelling agent is preferably made by kneading a drug mainly composed of an inorganic compound mainly composed of quick lime and silicate (for example, "Blystar" manufactured by Onoda Co., Ltd.) with water and kneading the mixture. Reacts with water (hydration reaction) so that its volume expands with time.

Other examples of the expanding agent include calcined dolomite, magnesia, ordinary Portland cement-blast furnace slag-bauxite-gypsum, alumina cement-lime-gypsum, and the like.

Due to the volume expansion of the expanding agent in each opening, the peripheral wall surface of each opening receives an expanding pressure in a direction perpendicular to the opening (in the radial direction of the through hole or hole).
Due to this inflation pressure, a portion between the openings of the mortar layer 20 rises and cracks occur in the portion. As a result, the mortar layer 20 peels off from the upright surface of the pillar 12.

The portion where the crack has occurred falls off the column 12 as a large number of crushed pieces naturally or by applying a relatively small external force. Since the mortar layer 20 peels off due to the static expansion effect of the expanding agent over time, noise and vibration do not occur.

After the mortar layer 20 has been peeled off, the position of the reinforcing bars in the column 12 is confirmed using a reinforcing bar (not shown). Next, a plurality of holes 26 are provided in a plurality of places of the column 12 where the reinforcing bars are not arranged, and are opened to a concrete surface 24 which is a surface appearing after the mortar layer 20 is peeled off. Implant. In the example shown,
Drill four holes 26 in each of the upper and lower parts of each pillar 12,
The anchor bolts 28 are partially inserted into the holes 26, and the anchor bolts 28 are connected to the pillars 12 using a synthetic resin adhesive.
Fixed to. As a result, a plurality of anchor bolts 28 project from the concrete surface 24 of the wall 12. Multiple holes 26
Are provided in the same number as the plurality of holes provided in the mounting plate 30 at the distal end of the brace 18 and are provided so as to correspond to the holes.

The holes 26 can be formed by using an ultrasonic cutting method as in the case of providing the openings in the mortar layer 20. Thus, the formation of the hole 26 can be performed with little noise and little vibration. Alternatively, the hole 26 can be formed by a cutting process using the drill in which the ultrasonic vibration is not superimposed. Also in this case, as in the case of the formation of the opening, the level of generated noise and vibration is higher than in the case of the ultrasonic cutting.

Next, a brace 18 having an X shape as a whole and having four tips is attached to both columns 12. To this end, the anchor bolts 28 are passed through holes in the plate 30 at each end of the brace 18, and then a nut (not shown) is screwed into each anchor bolt 28 projecting from each hole 30.
Each plate 30 is fastened to each column 12. This allows
Brace 18 is fixed to both columns 12.

Instead of the illustrated example extending in two linear directions intersecting with each other, the brace 18 may extend in only one linear direction and have two end portions facing each other. The installation of the braces 18 enhances the seismic resistance of the building 10.

In the illustrated example, the mortar layer 20 is peeled off,
The hole 2 which opens to the exposed concrete surface 24 by this
6 was cut into the frame. However, the holes 26 for implanting the anchor bolts 28 may be provided in the mortar layer 2 if necessary.
0 may be opened through the mortar layer 20 without peeling. That is, the mortar layer 2 which is the surface
Drill a hole in the surface of 0. This hole penetrates through the mortar layer 20 and extends through the concrete portion defining the concrete surface 24. The formation of this hole is also performed by applying the ultrasonic cutting method.

Also, in a concrete building,
In some cases, the skeleton is not covered with the mortar layer 20, and the surface of the skeleton is defined by exposed concrete. In this case, a hole 26 for implanting an anchor bolt 28 is made directly in the exposed concrete.
That is, a hole is made in the exposed concrete to open the concrete surface defined by the concrete. This hole is also formed by applying the ultrasonic cutting method.

After the brace 18 is attached, the frame is covered with a decorative plate or the like, if necessary.

[Brief description of the drawings]

Fig. 1 Pillars that are part of the skeleton of a concrete building,
It is a schematic longitudinal section of a wall and a beam.

FIG. 2 is a longitudinal sectional view similar to FIG. 1 after brace arrangement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Concrete building 12,14,16 Column, wall and beam 18 Brace 20 Mortar layer 24 Surface of pillar after mortar layer peeling 26 Hole 28 Anchor bolt

Claims (6)

[Claims] 1. A method for reinforcing an existing concrete building, comprising: drilling a plurality of holes in a building body of the building by ultrasonic cutting, the anchor holes being implanted in each hole; A reinforcing method, comprising fixing a brace to the skeleton via the anchor bolt. 2. The reinforcing method according to claim 1, wherein the surface of the skeleton is defined by concrete. 3. The reinforcing method according to claim 1, wherein the surface of the skeleton is defined by a mortar layer. 4. A method for reinforcing an existing concrete building, wherein a plurality of openings that are open to the surface of the building are formed in a part of a mortar layer that defines a surface of the building of the building. Filling the mortar layer with a swelling agent, and removing a part of the mortar layer from the skeleton by volume expansion of the swelling agent. Forming an anchor bolt in each hole, and fixing a brace to the skeleton via the anchor bolt. 5. The method according to claim 4, wherein the opening is formed by subjecting the mortar layer to ultrasonic cutting. 6. The method according to claim 4, wherein the holes are formed by subjecting the body to ultrasonic cutting.