JPH064983B2 - Concrete structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a concrete structure, and more particularly to a concrete structure obtained by applying shear reinforcement to an existing concrete structural member such as a pillar or a beam. Is.

(Prior Art) Conventionally, in order to impart seismic resistance to existing concrete structural members, a steel plate, a welded wire mesh, a composite material of a strip plate and mortar, a composite material of a strip plate and an epoxy resin, or various fiber reinforced plastics A method of applying a shear reinforcement member to an existing concrete structural member by a method such as winding has been proposed and implemented.

(Problems to be Solved by the Invention) However, in the conventional method of applying a reinforcing member, since the concrete structural member and the reinforcing member are integrated by using various adhesives, when a crack occurs in the concrete structural member. , Stress concentrates on the reinforcing member near the crack occurrence point, and the reinforcing member breaks when the crack width is small,
It has a drawback that the strength of the reinforcing member cannot be fully utilized.

(Means for Solving Problems) Therefore, as a result of intensive investigations by the present inventors to solve the conventional drawbacks, cracks were generated by installing the concrete structural member and the reinforcing member without integrating them. The present invention has been accomplished by finding that stress concentration on the reinforcing member that occurs at times is relaxed and the strength of the reinforcing member can be fully utilized.

That is, an object of the present invention is to provide a concrete structure capable of sufficiently exerting the effect of the shear reinforcing member. And, the purpose is a concrete structure obtained by applying a reinforcing member to the outer periphery of the concrete structural member, wherein an insulating member is interposed between the structural member and the reinforcing member in a non-adhesive state. Achieved by the concrete structure.

Hereinafter, the present invention will be described in detail.

As the concrete structural member used in the present invention, a concrete structural member such as a column or a beam in a conventional existing reinforced concrete structure or an existing steel frame reinforced concrete structure is used. Especially designed according to the design / calculation standards before 1969
Since the amount of shear reinforcement is small in the constructed reinforced concrete structure member, the shear reinforcement effect is large.

As the reinforcing member, any conventionally known reinforcing member can be applied. For example, a composite material in which plastic is reinforced with long fibers such as carbon fiber and glass fiber is preferable from the viewpoint of its own weight.
As the fiber, a fiber having high strength and high elasticity is particularly preferable because it has a great effect of suppressing the expansion of cracks generated in the concrete structural member.

Epoxy resin is generally used as the plastic.

The insulating member is not particularly limited as long as it causes slippage between the concrete structural member and the insulating member, the insulating member and the reinforcing member, or both when sandwiched between the concrete structural member and the reinforcing member. However, examples thereof include cellophane, polyester film, Teflon film, and oil-based paint. Of course, these materials are appropriately selected in consideration of the material of the reinforcing member and the relationship with the concrete member so that at least three members do not cause a bond due to a chemical reaction.

These insulating members are applied to the concrete structural member by a method such as winding and pasting, and a reinforcing member is also applied thereon, but in this case, the three members are not adhered so that they are not integrated. This is very important. When inorganic long fibers such as carbon fiber or glass fiber are used as the reinforcing member, the resin is applied to the fiber or pre-impregnated, and the resin is cured after being applied to the concrete structural member through the insulating member. You can also

In the concrete structure, since the insulating member exists between the concrete structure member and the reinforcing member in a non-bonded state, when an external force acts on the concrete structure and a crack occurs, the crack is directly adjacent to the concrete structure. Since it does not propagate to the reinforcing member, but propagates to the entire reinforcing member, the elongation ratio of the reinforcing member becomes a small value. As a result, the reinforcing member is not broken until the elongation limit of the reinforcing material is reached, and therefore it is possible to sufficiently exhibit the ability to absorb external force, that is, the energy absorbing performance.

Incidentally, on the outside of the concrete structure thus obtained, for the purpose of protecting the reinforcing member and making a decorative finish,
It is desirable to perform coating with any material.

(Effects) According to the present invention, it is possible to sufficiently utilize the strength of the reinforcing member and reduce the amount of the reinforcing member when the shear reinforcement of the existing concrete structural member is performed. Therefore, it becomes possible to perform shear reinforcement at a lower cost than in the prior art.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

(Example) An unreinforced concrete block having a hollow central portion (inner diameter 48 mm, outer diameter 150 mm, height 270 mm) was manufactured by a conventional method. The outline view is shown in FIG.

The outer circumference of the hollow concrete block is 60 μm thick
Was covered with an insulating member made of cellophane tape. A carbon fiber strand (6000 filament) as a reinforcing member is wound on the outside in a spiral shape at intervals of 5 mm while applying tensile force, and a room temperature curing type epoxy resin is applied. Immediately after that, a foil ester type strain gauge is applied with carbon. As shown in FIG. 1 and FIG. 2, it is attached at four places (strain amount measurement points A to D shown by 5 to 8) in the winding direction of the fiber,
The epoxy resin was cured at room temperature to produce a test concrete block (test sample A).

Also, for comparison, a test concrete block (test body B) similar to the test body A was manufactured except that the surface of the concrete block was coated with an epoxy resin primer instead of the insulating member.

In addition, at the same time, a concrete block for test (test body C) without any reinforcement was manufactured.

As a method for generating cracks in each test concrete block (test pieces A, B, C), a method of applying pressure from the inside of the concrete block was adopted.

As a pressurizing method, a static crushing agent (expansive material) used for crushing concrete, rocks, etc. was filled in the hollow portion of the concrete block and pressurized by the expansion pressure.

The strain amount of the carbon fiber, which is the reinforcing member, was measured using a strain measuring device.

As a result of the test, although the cracks of the test body C and the test body A were almost at the same time, the cracks continued to expand, and as a result, the test body C was broken. Although the crack generation of the test body B was slower than that of the other two bodies, the reinforcing member on the crack broke shortly after the crack generation, and the entire test body broke with the growth of the crack. It was confirmed that the strain amount of the carbon fiber was remarkably different depending on the measurement points, and that the reinforcing effect after the crack was generated was hardly present.

The crack generation time of the test body A was almost the same as that of the test body C, but the crack expansion / growth was slower than that of the test body B, so that the time until the fracture was remarkably slow. In addition, the change in strain of carbon fiber showed the same increasing tendency at all measurement points.

Table 1 shows the ratios of the maximum strain amounts of the carbon fiber portions of the test body A through the insulating member and the test body B according to the conventional technique. Here, in order to facilitate comparison between the two, the average value of the maximum strain amount of the carbon fiber portion at each strain amount measurement point of the test body A is set to 1.0, and the maximum strain amount at each measurement point of the test body A and B is It is expressed in the form of ratio to the average value.

As a result of these comparative experiments, it was found that the concrete structure reinforced by the insulating member has an excellent energy absorption capacity and can withstand large deformation sufficiently.

[Brief description of drawings]

FIG. 1 is a schematic view of a concrete block test body, FIG. 2 is a strain amount measuring point position on a plane of the test body, and FIG. 3 is a partially enlarged view of a plane cross section of the test body. 1 Concrete block 2 Hollow and static crushing agent 3 Reinforcing member 4 Insulating member 5 Strain amount measuring point A 6 〃 B 7 〃 C 8 〃 D

Claims (1)

[Claims] 1. A concrete structure comprising a concrete structural member provided with a reinforcing member on the outer circumference thereof, wherein an insulating member is interposed between the concrete structural member and the reinforcing member in a non-adhesive state. Concrete structure.