JP3242741B2 - How to reinforce steel structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing steel structures such as gas tanks and oil tanks, and more particularly to a method for reinforcing existing steel structures.

[0002]

2. Description of the Related Art Some existing steel structures have old design standards.
There are cases where reinforcement is required due to the fact that the structure is inferior to the structure based on the current standards because it is built according to the guidelines, and cases where reinforcement is required for the design load due to changes in load conditions after construction. In addition, it is often necessary to reinforce an existing steel structure, for example, when there is a defect in a welded portion due to poor construction work. As a conventional reinforcing method, a method of adding a steel plate by welding, a method of removing a defective welding portion, and re-performing welding have been performed.

[0003]

However, when these reinforcing methods are performed, for example, in a method of adding a steel plate by welding, welding work of a steel plate or the like at a construction site is indispensable, and welding is excellent in skill. Requires reliable work by skilled personnel. In addition, there is a problem that the reinforcing range is increased due to an increase in weight due to the addition of a steel plate. Further, in some existing steel structures, it may be difficult to use fire when reinforcing such as oil storage tanks when they are in use.
An object of the present invention is to provide a method for reinforcing a steel structure which can exhibit a large reinforcing effect by a simple operation.

[0004]

SUMMARY OF THE INVENTION In general, the present invention relates to a method for reinforcing a steel structure, wherein bisphenol A is added to the surface of a structural element to be reinforced. An epoxy primer of an epibis type synthesized from epichlorohydrin is applied, and then at least one uncured long-fiber high-temperature curing prepreg is attached via a room-temperature curing adhesive.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, the surface of a structural element to be reinforced with a steel structure is coated with an uncured long-fiber high-temperature-curable prepreg (hereinafter referred to as a prepreg ).
Below, in this specification, it abbreviates as a long fiber prepreg.)
To reinforce by pasting through a room temperature curing agent,
At this time, the present inventors have found that by applying a specific primer on the surface of the structural element in advance, the structural element and the prepreg are more firmly integrated and exhibit a large reinforcing effect, and have reached the present invention. .

Hereinafter, the present invention will be described in more detail. The uncured long fiber prepreg used in the present invention includes glass fibers, carbon fibers, and other reinforcing fibers arranged uniaxially or biaxially, knitted, woven, or randomly arranged. A matrix having a thickness of about 0.1 to 2 mm is impregnated with a thermosetting resin such as a phenol resin, an epoxy resin, an unsaturated polyester resin, a diallyl phthalate resin, a bismaleimide resin, a polyimide, a polyamide imide, or a polyurethane resin as a matrix. It is a shape.
As the prepreg, a high-temperature curing prepreg having a curing temperature of 70 ° C. or more is preferably used. This is for preventing the progress of curing at room temperature and improving the storage stability.
As long fibers, glass fibers, carbon fibers, vinylon fibers, aramid fibers, silicon carbide fibers, boron fibers, ceramic fibers, metal fibers, nylon fibers, polyester fibers and the like are used. The types of long fiber and thermosetting resin are
It may be appropriately selected according to the application, and two or more of these may be used in combination. As the long fiber prepreg, those having high strength and high elasticity are preferably used because they have a large effect of preventing deformation when reinforcing an existing steel structure.

[0007] As a primer, an epibis type epoxy primer synthesized from bisphenol A and epichlorohydrin is preferable because it has excellent integration between an existing steel structure and a long fiber prepreg as a reinforcing material.

As the cold-setting adhesive used in the present invention, preferably, an adhesive which cures at 10 to 40 ° C., any of those generally used can be used. For example, an adhesive is prepared by mixing a curing agent with a urea resin, a resorcin resin, a phenol resin, an epoxy resin, or the like as a base so as to be cured at room temperature. Particularly preferred adhesives include those based on a bisphenol A type epoxy resin and mixed with an amine curing agent. As the base, it is also preferable to select the same resin as the synthetic resin to be the matrix of the long fiber prepreg to be used in order to achieve the integration with the long fiber prepreg and the room temperature curing adhesive.

The cold-setting adhesive which cures at a temperature of 10 to 40 ° C. is preferably prepared as an adhesive solution having a viscosity of not more than 6,000 centipoise at 23 ° C., preferably 100 to 4000 centipoise. May be any type of solvent as long as the base such as an epoxy resin is soluble. For example, thinner, methyl ethyl ketone, acetone and the like can be exemplified. If the viscosity of the adhesive solution exceeds the upper limit of the above range, it is not preferable because the solution becomes too hard and the coating operation becomes difficult, and the penetration of the adhesive solution into the inside of the prepreg does not sufficiently proceed. In order to obtain the above-mentioned predetermined viscosity, it is advisable to mix 300 parts by weight or less, preferably 30 to 100 parts by weight, of the base with respect to 100 parts by weight of the solvent. Further, it is preferable to apply such an adhesive solution immediately before the application of the prepreg or within one hour thereof. As the coating method, various generally known coating methods can be adopted, and a method by impregnation is particularly preferable.

The amount of the adhesive solution applied is ¹⁰ to 200 g, preferably 20 to 100 g, per m ^{2 of} prepreg.
g.

[0011]

According to the present invention, the room-temperature-curable adhesive is brought into contact with the uncured long-fiber prepreg to promote the curing of the long-fiber prepreg, which takes a long time to cure at room temperature, and to reinforce it in a relatively short time. Can contribute to the development of strength.

Since the present invention uses a long fiber prepreg, it is lighter in weight than reinforcement by a steel plate or the like, and an increase in weight can be prevented. The strength and amount of the prepreg to be used can be appropriately selected according to the purpose. After reinforcement, a colored coating may be applied.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

Example 1 FIG. 1 is an outline view of a case where a long fiber prepreg is stuck to an existing steel storage tank by the method of the present invention, and FIG. 2 is an enlarged cross-sectional view of a reinforcing portion where a long fiber prepreg is stuck in three layers. is there. FIG.
, 1 is an existing steel storage tank, 2 is a long fiber prepreg, 3 is a first layer long fiber prepreg, 4 is a second layer long fiber prepreg, 5 is a third layer long fiber prepreg,
Reference numeral 6 denotes a primer, and reference numeral 7 denotes a room temperature-curable adhesive. Hereinafter, the method of the present invention will be described with reference to FIG. Existing steel storage tank 1
A primer 6 is applied to the outer surface of the substrate to improve the affinity with the adhesive. As the primer, an epoxy-type epoxy primer is preferably used for improving the affinity. After the primer 6 is cured, a room temperature curing adhesive 7 is applied. It is preferable that the cold-setting adhesive is appropriately diluted with a thinner for use in improving workability. Immediately after the application of the cold-setting adhesive 7, the first layer long fiber prepreg 3 is attached. When the long fiber prepreg is one in which long fibers are arranged in a uniaxial direction, it is preferable that the long fiber prepreg be attached so that the arrangement direction of the long fibers coincides with the direction in which the long fibers are reinforced. After the long fiber prepreg 3 is attached, the room temperature curing adhesive 7 is applied to the long fiber prepreg 3.
Then, the second layer of long-fiber prepreg 4 is immediately attached in the same manner as the first-layer long-fiber prepreg 3, and then the room-temperature-curable adhesive 7 is applied. Thereafter, the third layer long fiber prepreg 5 is adhered by the same method, and then the room temperature curing adhesive 7 is applied. When the hardening of the cold-setting adhesive 7 proceeds, the reinforcement work by the method of the present invention is completed. Further, when an aesthetic appearance is required, the coating 8 is appropriately applied.

The description based on FIG. 2 is for a case where three layers of long fiber prepregs are laminated, but the number of layers is appropriately selected according to the required reinforcing amount and the strength per one long fiber prepreg.

[0016]

According to the method of the present invention, the uncured long fiber prepreg can be adhered sufficiently following the irregularities on the surface of the existing steel structure, and the stress from the existing steel structure can be reduced. Since the transmission is also facilitated, a reinforcing method that makes full use of the strength of the long fiber as the reinforcing material is provided. ADVANTAGE OF THE INVENTION According to the method of this invention, even if the surface of the component of the existing steel structure has a complicated shape like a curved surface, the reinforcement method which can implement sufficient reinforcement easily is provided. According to the method of the present invention, by using an uncured long-fiber prepreg and a room-temperature-curable adhesive together, a special step such as heat curing is not required, and the reinforcing cure is exhibited in a short time. A reinforcement method is provided. Further, according to the method of the present invention, by using long fibers having a high specific strength as a reinforcing material, the weight increase due to the reinforcement can be significantly reduced, thereby increasing the range of reinforcement or the reinforcement that does not require reinforcement of the foundation. A method is provided. According to the method of the present invention, there is further provided a reinforcing method capable of being transported without using a hoist or the like and having a simple and easy sticking operation because the reinforcing material is lightweight.

[Brief description of the drawings]

FIG. 1 is a schematic view of a case where a long fiber prepreg is laminated on an existing steel storage tank.

FIG. 2 is an enlarged sectional view of a reinforcing portion.

[Explanation of symbols]

1: existing steel storage tank, 2: long fiber prepreg, 3: first layer long fiber prepreg, 4: second layer long fiber prepreg, 5: third layer long fiber prepreg, 6: primer, 7: Room temperature curing adhesive

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B32B 15/08

Claims (1)

(57) [Claims] An epoxy primer of an epibis type synthesized from bisphenol A and epichlorohydrin is applied to a surface of a structural element to be reinforced for a steel structure,
A method for reinforcing a steel structure, comprising: attaching at least one uncured long-fiber high-temperature-curable prepreg via a room-temperature-curable adhesive.