JPS61151371A - Reinforcement of existing pillar - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention relates to a method of reinforcing column members of existing structures, and in particular, increases the strength of column members by using carbon fibers.

This invention relates to a reinforcing method that increases toughness.

(Prior art and its problems) Conventionally, as a reinforcement method for concrete column members of existing structures, adding walls, places, side walls, etc.
It was mainly intended to increase the strength of structures.

However, such reinforcement methods require major changes in the function or design of the structure before reinforcement, and various constraints must be taken into consideration when formulating a reinforcement plan.
It was difficult to provide the desired reinforcement.

In addition, other reinforcement methods include surrounding the existing column members with steel plates, or surrounding the existing column members with welded wire mesh or reinforcing bars, mainly to improve the toughness of the column members.
Reinforcement methods are also provided that are intended to not reduce the load carrying capacity and energy consumption capacity in the event of damage.
According to this method, there are fewer restrictions on the function and design of the structure.

However, this reinforcing method requires welding of steel plates and the like on site, and the welding must be reliably performed by a highly skilled person in order to obtain the desired reinforcement.

In addition, mortar, etc., will be injected between the existing column members and the steel plates, welded wire mesh, and reinforcing bars to transmit stress, but it is not possible to fill the injected mortar densely between these. was difficult.

Furthermore, in the above-mentioned reinforcement methods, slits are generally provided at the ends of reinforcement members such as steel plates in order to increase only the shear strength of existing column members and maintain the same bending strength as before reinforcement. In the case of a member located in the area, rainwater is not easily covered in this area, and as a result, a water leakage accident is likely to occur.

Furthermore, in the reinforcing method using steel plates, rust prevention measures must be taken on the steel plates, resulting in an increase in maintenance and management costs.

By the way, conventionally, when constructing a concrete column member, a method has been provided in which spiral reinforcing reinforcing bars are buried to dramatically improve the toughness of the column member.

Concrete generally deforms in three dimensions when force is applied.
However, in this case, it is known that if restraints are applied so that deformation occurs only in one direction, the progress of the fracture will be significantly delayed. This is what was used.

Therefore, it is possible to use the spiral reinforcing bars mentioned above to reinforce the column members of existing structures, but if you want to reliably obtain the restraining effect of the spiral reinforcing bars, it is necessary to create a gap between the spiral reinforcing bars and the existing column members. Although it is possible to prevent this from occurring, it is extremely difficult and expensive to process reinforcing bars in this way, making it almost impossible in practice.

Therefore, in practice, we ended up adopting a method of injecting mortar between the spiral reinforcing bars and the column members, but this method has the same unresolved construction problems as the reinforcement method using steel plates etc. mentioned above. becomes.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to improve the strength and toughness of column members to reinforce structures, and to require a high degree of skill in construction. To provide a method for reinforcing existing columns that is unnecessary, can easily ensure construction accuracy, and is easy to maintain.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a method for reinforcing existing columns, in which a high-strength carbon long fiber strand is spirally wound around a column member of an existing structure, and then the long fiber strand is wound around a column member of an existing structure. The finishing material is applied by embedding the strands.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show an embodiment of the method for reinforcing an existing column according to the present invention.

The reinforcing method shown in the figure is applied to reinforcing an existing column member 10 with a square cross section, which is commonly used.

The existing column member 10 usually has a finished part 2 made of mortar or the like, so this is first cut off to expose the concrete body part 1 of the column member 10, as shown in Fig. 1(b). do.

Next, as shown in FIG.
By pouring mortar or concrete into the central part of each side of the frame to make the part bulge 4, or by using both of these in combination, the frame part 1 is shaped so that it has a roughly circular cross-sectional shape. do.

Here, the reason why the cross section of the frame 1 of the column member 10 is made almost circular is that when the high tension a carbon long fiber strand 5 is spirally wound as described later, the reason why the cross section of the frame 1 of the column member 10 is made almost circular is that This is because the cross-sectional shape provides the most efficient radial restraint and the highest reinforcing effect.

In addition, since the roughly circular cross section does not have any acute angles, it is possible to tightly wind the carbon long strands 5 around the outer surface of the body part 1, and the long carbon fibers have relatively low strength in the radial direction. This is also to significantly reduce the risk of damaging the strands 5.

Thereafter, as shown in FIG. 1(d), high-strength carbon long fiber strands 5 are tightly wound around the shaped outer surface of the frame portion 1 having a circular cross section to form a spiral reinforcing element.

The long carbon fiber strand 5 is made by twisting a large number of wires together, or by twisting together a string-like body made of wire rope, cable, etc. Even if the strand 5 deviates slightly from the circular cross section, the strand 5 is highly flexible, so it will fit well with the side body surface of the column 1 and provide a good restraining effect, and when it is wound around the body part 1, , as shown in Figure 2, it is better to wind the spirals densely at both ends of the body part 1 and loosely in the middle, so that the pitch of the spirals is not uniform, but rather unevenly arranged, which is better for structural mechanics and materials. Excellent in terms of cost savings.

When the winding of strand 5 is completed, as shown in Fig. 1(e)
As shown in FIG.
It functions as a fireproof coating for the 1AN strands 5.

The finishing material 6 is applied by applying mortar or by spraying mortar, and the work is completed so that the strands 5 are completely insulated from the air. Figure 3 shows the side view of this state. It is a diagram.

Now, in the method for reinforcing existing columns configured as described above, the reinforcing effect of spiral reinforcing bars, which have been widely adopted in the past when constructing new columns, can be obtained for the existing column members 10 to the same or higher level. be able to.

In addition, since the carbon long fiber strands 5 are flexible and can change the spiral pitch arbitrarily, the existing column member 10 can be locally or intensively reinforced at necessary locations.

Furthermore, to confirm the quality of construction, carbon long fiber strand 5
It is only necessary to visually judge whether or not the area is completely covered with the finishing material 6, and this is done reliably and
It is not as difficult as traditional mortar pouring work and is much easier.

Furthermore, unlike conventional reinforcement methods, slits etc. are not provided, so rain protection measures can be carried out using normal construction methods, and design and
Not only can the construction be made more efficient, but since no welding work is required, there is no need for skilled workers, resulting in significant economic benefits.

In addition, in the above embodiment, the existing column member 10 is exemplified as having a square cross section, but the implementation of the present invention is not limited to this, and the rectangle may be circular, oval, etc. If the pillar member 10 is circular or oval, the finished part 2 applied to the existing pillar member 10 is cut off, and then the carbon long fiber strand 5 is immediately cut off.
This can be done in the process of winding.

In addition, if the existing column member 10 has a rectangular cross section such as a square or a rectangular parallelepiped, the diameter of the carbon long fiber strand 5 wound around it may be increased instead of shaping the cross section of the frame 1 of the column member 10 into a circle. Even if it is made denser, the same effect as in the above embodiment can be obtained.

(Effects of the Invention) As described above in detail in the examples, according to the method for reinforcing existing columns according to the present invention, the strength and toughness of existing column members are improved in the same way as spiral reinforcing bars, and the structure Various excellent functions and effects can be obtained, such as being able to strengthen the earthquake resistance of objects, making it easy to construct, and easily ensuring construction accuracy.

[Brief explanation of the drawing]

FIGS. 1(a, ) to <8) are sectional views sequentially showing the steps of the reinforcing method of the present invention. Figure 2 is a side view of Figure 1(d), Figure 3 is a side view of Figure 1(d), and Figure 3 is a side view of Figure 1(d).
3) is a side view. 10... Existing column members 1...
Body part 2... Finished part 3...
...Corner portion 4...Bulging portion 5...High strength carbon long fiber strand 6.
...Finishing material patent applicant Obayashi Co., Ltd. Agent Patent attorney - Kensuke Shiro (d)
(e) Title 2II Figure 3 procedural amendment (self-imposed January 29, 1985)

Claims (2)

[Claims] (1) Reinforcement of existing columns characterized by winding high-strength carbon long fiber strands in a spiral shape around the column members of existing structures, and then applying finishing material to embed the long fiber strands. Method. (2) The high-strength carbon long fiber strand is wound loosely in the middle part of the pillar member and densely wound in both ends. Reinforcement method.