JP2002206348A - Clamping tool for concrete column and clamping method using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clamping tool for reinforcing a concrete column against earthquakes, as emergency measures to prevent a building which has once escaped collapse in an earthquake from collapsing due to aftershocks, and a clamping method using it. SOLUTION: A tensioning member 2 is a strip with looped joint locking parts 3 and 3' formed at both ends and is wound around a concrete column 1. Support members 4 and 4' projecting in the cross direction of the tensioning strip member 2 are passed through the opposite joint locking parts 3 and 3', and upper and lower projecting parts are connected together by a clamping means 5. The clamping means 5 comprises the support members 4 and 4' each having through holes 4a at both ends, and a clamping fitting 6 passed through the through holes 4a provided in the support members 4 and 4' to connect the support members together. During construction work, the clamping fitting 6 is clamped by use of a tool or the like to apply tension to the tensioning member 2 and a lateral prestress produced by a peripheral compressive force is applied to the concrete column 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to seismic reinforcement of concrete pillars used for pillars of buildings and the like, and more specifically, to protect buildings that have been once collapsed from an earthquake from collapses caused by aftershocks. As a first aid measure, the present invention relates to a fastening tool for temporarily reinforcing a concrete pillar and a fastening method using the same.

[0002]

2. Description of the Related Art Buildings that have survived a collapse due to an earthquake striking a reinforced concrete structure often collapse due to aftershocks. Protecting such buildings from aftershocks is an urgent countermeasure in the event of an earthquake. One.

[0003] In recent years, in the event of an earthquake in Kagoshima, it has been reported that schools with cracked pillars were able to withstand the same magnitude earthquake that occurred several months later by enclosing the pillars with steel plates. The importance of seismic retrofit after the disaster is pointed out.

[0004]

However, apart from the case where there is sufficient time as described above, since aftershocks generally strike several hours later, if a large aftershock is expected, A quicker response is needed.

Conventionally, as a first-aid measure for protecting a building that has once been protected from a collapse from an earthquake from a collapse caused by an aftershock, as described above, only a measure that merely surrounds the periphery of a pillar with an iron plate or the like is used. Missing, this was not enough to protect the shear rupture of the concrete columns from aftershocks.

According to the present invention, a compressive force is applied from the periphery to a concrete column in which a crack or the like has once formed to apply a lateral prestress to the concrete column, thereby causing the concrete to adhere and re-aggregate. (Reinforced concrete) The purpose of this project was to focus on protecting the collapse of buildings from aftershocks on a temporary basis by promoting the original strength.

[0007] Therefore, as the reinforcing means, (a)
Flexibility in the shape and dimensions of the pillars, (b) easy installation without the need for special tools and power, etc. (c) Reinforcement tools are lightweight and suitable for transportation and storage (D) Reinforcement tools must be easily removable and reusable, etc.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fastening tool for providing seismic reinforcement satisfying the above-mentioned various requirements as an emergency measure to protect a building once protected from collapse from an earthquake from a collapse due to an aftershock. It is to provide a tightening method that is used.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the invention of a tightening tool according to the present invention is characterized in that a band-shaped tensioning member having joint engaging portions at both ends, and the joint engaging portions are connected to each other for tightening. The fastening means comprises a support member attached to each of the joint locking portions, and a fastening member for connecting the support members to each other and adjusting the tension. It consists of.

Thus, the belt-like tension member wound around the concrete pillar is deformed in accordance with the shape of the pillar, and the support members provided at both ends thereof and the fastening fitting for connecting the support members to each other are tightened. Since the force can be adjusted, there is an advantage in that it has flexibility in the shape and dimensions of the column, and the reinforcing tool is lightweight and suitable for transportation and storage.

Further, the invention of the tightening method of the present application is a method of tightening around a concrete column with a belt-like tightening member,
A belt-shaped tensioning member is wound around the concrete column, both ends of the band-shaped tensioning member are connected to each other by fastening means, and the concrete column is tightened by the band-shaped tensioning member with a constant tension. When reinforcing a concrete pillar having a corner, a supporting member is interposed between the corner of the concrete pillar and the belt-shaped tensioning member.

Thus, the band-shaped tension member wound around the concrete column is tensioned by the manual tightening of the fastener by the fastening means, and the concrete column receives a compressive force from the periphery, and the concrete column receives the compressive force. Is applied with a lateral prestressing stress, and the concrete is brought into close contact and re-agglomerated state, and the strength of the concrete is promoted, so that the concrete column can be prevented from being broken by aftershocks. Therefore, there is an advantage that the reinforcing work can be performed without requiring a special tool or power, and the reinforcing tool can be easily removed and used again.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In each of the drawings, the same components are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 1 is a perspective view showing an embodiment of the present invention, in which reinforcing work is applied to a cylindrical concrete pillar, and FIG.
1 shows a cross-sectional view taken along the line AA in FIG.

As shown in FIGS. 1 and 2, a strip-shaped tensioning member 2 is wound around a concrete pillar 1. As shown in FIGS. 3A and 3B, the tension member 2 is a belt-shaped body having loop-shaped joint locking portions 3 and 3 'formed at both ends thereof. Fig. 4
As shown in (a) and (b), the supporting members 4, 4 'projecting in the width direction of the band-shaped tension member 2 are inserted into the joint locking portions 3, 3' facing each other, and the supporting members 4, 4 ' The upper and lower projecting portions are connected by fastening means 5.

That is, the fastening means 5 comprises support members 4, 4 'having through holes 4a at both ends, and bolts and nuts which are inserted into and connected to the through holes 4a provided in the support members 4, 4'. At the time of construction, tension is applied to the belt-shaped tension member 2 by tightening the fastener 6 using a ratchet wrench or the like, and the lateral prestress is applied to the concrete column 1 by compressive force from the surroundings. The configuration is such that stress is applied. As a result, the concrete
G is brought into a state of cohesion and re-agglomeration, and promotes the original strength of RC (reinforced concrete).

Here, the interface between the support members 4 and 4 ′ on the side where the support members 4 and 4 ′ are in contact with the belt-shaped tension member 2 is formed by tension.
Is preferably formed on a curved surface having a large radius of curvature so as not to be damaged.

Since a force of about 3 to 10 tons is usually applied to the belt-shaped tensioning member 2, a synthetic fiber which is lightweight, has high strength, and has little change over time is used. From this perspective,
The material of the belt-shaped tension member 2 is selected from polyamide fibers, aromatic polyamide fibers, polyester fibers, and polyparaphenylene benzobisoxazole fibers.

Next, FIG. 5 is a part of a perspective view showing another embodiment of the present invention, in which reinforcing work is applied to a prismatic concrete pillar, and FIG. FIG.

In the reinforcing work of the above-mentioned prismatic concrete pillar, when the belt-like tensioning member 2 is wound around the concrete pillar 1, as shown in FIG.
A supporting member 8 is interposed at a position facing the corner 7 of the concrete column 1, and the concrete column 1 is compressed from the periphery through the supporting member 8 by the tension T of the band-shaped tension member 2. A force P is applied to apply a lateral prestress stress to the concrete column 1. As a result, the concrete is brought into the state of cohesion and re-aggregation, which promotes the original strength of RC.

The bearing member 8 is made of a material such as iron, aluminum alloy, stainless steel or the like. As shown in FIG. 7, the surface in contact with the belt-shaped tension member 2 is formed to have a curved surface having a large radius of curvature. Thus, the belt-shaped tension member 2 can smoothly slide on the surface of the support member 8 during construction or removal.

Here, in consideration of workability at the time of construction, a supporting member 8 is previously mounted at a position facing the corner 7 of the concrete pillar 1 on the inner surface of the belt-shaped tensioning member 2 and several types of supporting members are provided. It is preferable to prepare these so that they can be used properly depending on the situation at the site.

In addition, in the case of reinforcement of a prismatic concrete pillar, as shown in FIG. 8, depending on the shape of the corner 7 of the concrete pillar 1, in addition to the bearing member 8, a bearing stress may be applied. It is necessary to interpose a spacer 9 as a dispersing material between the concrete column 1 and the supporting member 8 so that the surface of the corner 7 of the concrete column 1 is not damaged.

In many cases, various processes are applied to the surface of the prismatic concrete pillar. For example, as shown in FIG. 9, a shutter pillar is provided on the concrete pillar 1 at the entrance of the parking lot. In some cases, a tile 10 is attached, and a tile finish 11 is applied to one surface thereof.

When the concrete pillar 1 is subjected to the emergency reinforcement according to the present invention, as shown in FIG. 10, the concrete pillar 1 is used to prevent the inner surface of the band-shaped tension member 2 from being damaged. A pressing plate 12 made of an iron plate, a wooden plate, a rubber plate, or other waste material is interposed between the tension member 1 and the band-shaped tension member 2 as a bearing stress dispersing material, so that the shutter rail 10 does not hinder the tightening. Not to be.

The narrower the interval between the band-shaped tension members 2 wound around the concrete column 1, the better the strength is. However, it is not necessary to wind a large number of band-shaped tension members 2 at an interval smaller than necessary. Since the spacing between the belt-shaped tension members 2 affects the distribution of bearing pressure in the longitudinal direction of the concrete column 1, the shear failure of the concrete column 1 is 4 times in the longitudinal direction.
It is necessary to distribute the bearing pressure so that the line of 5 degrees does not pass through the bearing pressure range.

Therefore, as shown in FIGS. 11 and 12,
When the interval h between the band-shaped tension members 2 is larger than the width w of the concrete pillar 1, the bending material 13 or the angle material 14 that straddles the adjacent band-shaped tension members 2 is interposed as a bearing stress dispersing material. It is preferable to achieve pressure distribution.

In the construction of the seismic reinforcement according to the present invention, the lateral prestress stress applied to the concrete column 1 is 0.2
It is preferable to adjust so as to be 4.0 N / mm ² .
If it is less than 0.2 N / mm ² , the reinforcing effect cannot be obtained sufficiently,
If it exceeds N / mm ² , the reinforcing effect becomes saturated.

In this way, after the aftershock has completely passed, the strip-shaped tension member 2 is removed from the concrete column 1 which has been prevented from collapsing due to the aftershock, and full-scale reinforcement is performed. Then, the removed fastening tool is used again.

[Examples] Concrete short pillars with cracks (shear span ratio 1.5, concrete strength 20)
N / mm ² , main bar ratio 1.36%, band bar ratio 0.08%) when no lateral prestress is applied, and 0.43 N / mm
The fracture strength when the lateral prestressing stress of No. ² was applied was measured.

As a result, when a lateral prestress stress is applied, the member angle is 2.5% under the condition of the axial force ratio of 0.2.
The endurance decrease until 20% of the peak showed bending failure, but when the lateral prestress stress was not applied,
Shear fracture occurred at a member angle of 0.5%.

The reinforcing effect was confirmed by using the same concrete short pillar as described above and changing the magnitude of the applied lateral prestress stress. A remarkable effect began to appear from around 0.2 N / mm ² , and it was confirmed that the effect gradually increased up to around 4.0 N / mm ² , and that the effect became saturated above that.

[0034]

The tightening device of the present invention is constituted by a belt-like tension member and a fastening means for connecting both ends thereof.
There is an advantage that the structure of the fastening tool itself is simple, lightweight, suitable for transportation and storage, and has flexibility in the shape and dimensions of the column.

According to the invention of the tightening method, the belt-shaped tightening member can be tightened by manually tightening the fastener using a ratchet wrench or the like, so that no special tool or power is required. There is an advantage that the reinforcement work can be performed in a short time, and that the reinforcement tool can be easily removed and used again.

[Brief description of the drawings]

FIG. 1 shows a part of a perspective view for explaining an embodiment in which a reinforcing column of the present invention is applied to a cylindrical concrete pillar.

FIG. 2 is a cross-sectional view of the column-shaped concrete pillar shown in FIG.

FIGS. 3 (a) and 3 (b) are a front view and a side view for explaining an embodiment of the belt-shaped tensioning member of the present invention.

FIGS. 4A and 4B are a front view and a plan view of a connecting portion in a state where the belt-shaped tensioning member of the present invention is connected.

FIG. 5 is a perspective view showing a case where the reinforcing work of the present invention is applied to a rectangular concrete pillar.

FIG. 6 is a sectional view of the prismatic concrete pillar shown in FIG.

FIG. 7 is a partially enlarged explanatory view showing one embodiment of a corner portion of a concrete pillar in the case where the reinforcing work of the present invention is applied to a rectangular concrete pillar.

FIG. 8 is a partially enlarged explanatory view showing another embodiment of a corner portion of a concrete pillar when the reinforcing work of the present invention is applied to the concrete pillar.

FIG. 9 is an explanatory sectional view showing an example of a form of a prismatic concrete pillar at the entrance of a parking lot.

FIG. 10 is a part of an elevation view for explaining another embodiment in which the reinforcing work of the present invention is applied to a cylindrical concrete pillar.

FIG. 11 is a perspective view for explaining another embodiment in a case where the reinforcing work of the present invention is applied to a cylindrical concrete pillar.

FIG. 12 is a perspective view for explaining another embodiment in a case where the reinforcing work of the present invention is applied to a prismatic concrete pillar.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Concrete pillar 2 Belt-shaped tension member 3 Joint locking part 4, 4 'Support member 4a Through hole 5 Fastening means 6 Adjusting fastener 7 Corner 8 Supporting member 9 Spacer 10 Shutter rail Le 11 Tile finish 12 Holding plate 13 Curved material 14 Angle material

Claims (8)

[Claims] 1. A concrete column tightening tool comprising: a band-shaped tension member having joint engagement portions at both ends; and fastening means for connecting and fastening the joint engagement portions to each other. 2. The fastening means connects a supporting member mounted on each of the joint locking portions to the supporting member,
2. The concrete column tightening tool according to claim 1, further comprising a tightening member capable of adjusting a tension. 3. A concrete inside the belt-like tension member.
2. A supporting member facing the corner of the pillar.
Or the fastening device for a concrete pillar according to 2. 4. The belt-shaped tensioning member is a polyamide fiber,
4. A fiber made of one material selected from aromatic polyamide fibers, polyester fibers, and polyparaphenylene benzobisoxazole fibers.
6. The concrete column tightening tool according to claim 1. 5. A method for tightening the periphery of a concrete column with a band-shaped tension member, wherein the band-shaped tension member is wound around the concrete column, and both ends of the band-shaped tension member are connected to each other by fastening means. A concrete column tightening method in which the concrete column is tightened with a constant tension by a band-shaped tension member. 6. The concrete column tightening method according to claim 5, wherein when the belt-like tension member is wound around the concrete column, the concrete column is tightened with a bearing stress dispersing material interposed therebetween. . 7. When the band-shaped tensioning member is wound around a concrete pillar having a corner, the supporting member is interposed between the corner of the concrete pillar and the belt-shaped tensioning member, and tightened. 7. The concrete column tightening method according to 5 or 6. 8. The fastening by the fastening means such that when the periphery of the concrete column is tightened with a band-shaped tensioning member, the lateral prestressing stress applied to the concrete column is 0.2 to 4.0 N / mm ^2. 8. The method for tightening a concrete column according to claim 5, wherein the force is adjusted.