JP5779003B2 - Method for reinforcing steel structure and laminated material for reinforcing steel structure - Google Patents

Description

  The present invention uses a sheet-like or plate-like reinforcing fiber-containing material containing continuous reinforcing fibers to repair and reinforce steel structures such as bridges, buildings, and machines (hereinafter simply referred to as “reinforcement”). The present invention relates to a method for reinforcing a structure and a laminated material for reinforcing a steel structure.

  Conventionally, a method of reducing the stress level of an existing steel material by welding a steel plate to the surface of the steel material of a structure to be reinforced or welding with a high-strength bolt has been implemented. However, this method requires welding and drilling, and the weight of the reinforcing steel plate is large, so that the construction becomes large, and there is a possibility of structural weaknesses such as residual stress due to welding and cross-sectional defects due to drilling.

  Therefore, in recent years, there has been proposed a method of reducing the stress level of an existing steel material by attaching a reinforcing fiber-containing material to the surface of the steel material of the structure to be reinforced with an adhesive because welding and drilling are unnecessary and the construction is simple. (For example, see Patent Document 1).

JP 2003-193425 A

  As described above, the reinforcement method of attaching the reinforcing fiber-containing material to the steel structure with an adhesive has the advantage that the material is lightweight and easy to handle during construction, and can be reinforced simply by bonding. It is mentioned that special processing such as providing bolt holes in steel is not necessary.

  However, for example, as a reinforcing fiber-containing material, for example, a carbon fiber reinforced resin plate (hereinafter referred to as “CFRP plate”) obtained by impregnating a resin into carbon fiber and cured has a linear expansion coefficient of approximately 0 μ / ° C. When the temperature is changed, internal stress (ie, thermal stress) is generated in the steel material to which the CFRP plate is bonded. Since the CFRP plate is bonded as a reinforcing method for reducing the stress generated in the steel material, it is not preferable that a thermal stress is generated in the steel material in response to a temperature change.

  Therefore, as a result of many research experiments, the inventors have a linear expansion coefficient larger than that of steel, for example, by bonding an aluminum alloy plate having a linear expansion coefficient approximately twice that of steel to a steel plate together with a CFRP plate. It has been found that the thermal stress generated in the steel sheet due to temperature change and the thermal stress generated in the bonding interface between the steel sheet and the reinforcing material (CFRP plate + aluminum alloy plate) can be reduced.

  The present invention is based on such novel findings of the present inventors.

  The object of the present invention is to reduce the thermal stress generated at the bonding interface between the reinforcing material bonded to the steel structure surface and the steel material surface due to temperature change, and the thermal stress generated in the steel material, thereby obtaining a sufficient reinforcing effect. The present invention is to provide a method for reinforcing a steel structure and a laminated material for reinforcing a steel structure.

The above object is achieved by the steel structure reinforcing method and the steel structure reinforcing laminate according to the present invention. In summary, according to the first aspect of the present invention, in the method for reinforcing a steel structure, the reinforcing material is bonded to the surface of the steel material constituting the steel structure with an adhesive.
The reinforcing material is composed of a reinforcing fiber-containing material having a smaller linear expansion coefficient than the steel material constituting the steel structure, and an alloy plate having a larger linear expansion coefficient than the steel material,
At least one layer of the reinforcing fiber-containing material and the alloy plate are alternately bonded and laminated on the surface of the steel material with an adhesive, and the steel material, and the reinforcing material and the steel material by temperature change of the steel material. There is provided a method for reinforcing a steel structure, characterized in that thermal stress generated at the bonding interface of the steel structure is reduced.

According to the second aspect of the present invention, in the method for reinforcing a steel structure in which the reinforcing material is bonded to the surface of the steel material constituting the steel structure with an adhesive,
The reinforcing material is composed of a reinforcing fiber-containing material having a smaller linear expansion coefficient than that of the steel material constituting the steel structure and an alloy plate having a larger linear expansion coefficient than that of the steel material. Is composed of
The reinforcing material is bonded to the surface of the steel material with an adhesive, and thermal stress generated at the bonding interface between the steel material and the reinforcing material and the steel material due to a temperature change of the steel material is reduced. A method of reinforcing a steel structure is provided.

According to a third aspect of the present invention, there is provided a steel structure reinforcing laminate for reinforcing a steel structure by bonding with an adhesive to the surface of the steel material constituting the steel structure,
The reinforcing fiber-containing material having a smaller linear expansion coefficient than that of the steel material constituting the steel structure and the alloy plate having a larger linear expansion coefficient than that of the steel material are alternately laminated at least one layer with an adhesive. A laminated material for reinforcing a steel structure is provided.

  According to an embodiment of the present invention, the reinforcing material or the steel structure reinforcing laminated material has at least three layers of the reinforcing fiber-containing material, the alloy plate, and the reinforcing fiber-containing material. Further, the reinforcing fiber-containing material is bonded to the steel material surface.

  According to another embodiment of the present invention, the reinforcing material or the steel structure reinforcing laminated material has at least three layers of the alloy plate, the reinforcing fiber-containing material, and the alloy plate. The alloy plate is bonded to the steel surface.

  According to another embodiment of the present invention, the linear expansion coefficient (αs) of the steel material is 10 (μ / ° C.) ≦ αs ≦ 12 (μ / ° C.), and the reinforcing fiber-containing material bonded to the steel material The linear expansion coefficient (αf) of the alloy plate is −15 (μ / ° C.) ≦ αf <αs, and the linear expansion coefficient (αa) of the alloy plate is αs <αa ≦ 30 (μ / ° C.).

  According to another embodiment of the present invention, the thickness of each layer of the reinforcing fiber-containing material (FRP plate) and the alloy plate bonded to the steel material is calculated by the following equation.

  According to another embodiment of the present invention, the reinforcing fiber-containing material is made of a fiber sheet in which continuous reinforcing fibers arranged in one direction are fixed to each other with a wire fixing material, or a matrix is formed on the reinforcing fibers. A plurality of continuous fiber reinforced plastic wires impregnated with resin and hardened, are made of a fiber sheet in which the wires are arranged in a slender shape in the longitudinal direction, and the wires are fixed to each other with the wire fixing material, or in one direction It is a fiber reinforced resin plate in which a continuous reinforcing fiber sheet that is aligned is impregnated with a resin and the resin is cured.

  According to another embodiment of the present invention, the alloy plate is an aluminum alloy, a stainless alloy, or a magnesium alloy.

According to another embodiment of the present invention, the reinforcing fiber of the reinforcing fiber-containing material may be carbon fiber, glass fiber, inorganic fiber such as basalt fiber, or aramid, PBO (polyparaphenylene benzbisoxazole), polyamide, poly Organic fibers such as arylate and polyester are used alone or in a hybrid mixed with multiple types,
The matrix resin impregnated in the reinforcing fiber-containing material and the adhesive are heat-curable epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, phenol resin, etc. It is a curable resin or a thermoplastic resin such as nylon or vinylon.

  According to the steel structure reinforcing method and the steel structure reinforcing laminated material of the present invention, thermal stress generated at the bonding interface between the reinforcing material bonded to the steel structure surface and the steel material surface due to temperature change, and The thermal stress generated in the steel material can be reduced and a sufficient reinforcing effect can be obtained.

It is sectional drawing for demonstrating the Example of the reinforcement method of the steel structure of this invention. It is a figure which shows one Example of the fiber sheet for producing the reinforcing fiber containing material used for the reinforcement method of the steel structure of this invention. It is a figure which shows one Example of the fiber reinforced resin board for producing the reinforced fiber containing material used for the reinforcement method of the steel structure of this invention. It is a perspective view which shows the other Example of the fiber sheet for producing the reinforcing fiber containing material used for the reinforcement method of the steel structure of this invention. It is sectional drawing of the fiber reinforced plastic wire which comprises the fiber sheet shown in FIG. It is a perspective view which shows the other Example of the fiber sheet for producing the reinforcing fiber containing material used for the reinforcement method of the steel structure of this invention. It is a perspective view which shows one Example of the alloy plate used for the reinforcement method of the steel structure of this invention. It is process drawing explaining one Example of the reinforcement method of the steel structure of this invention. It is process drawing explaining the other Example of the reinforcement method of the steel structure of this invention. It is a figure explaining the structure of the various test body for demonstrating the reinforcement method of the steel structure of this invention. It is a figure explaining the attachment position of the strain gauge in the temperature change test of the test body reinforced according to this invention. It is a figure which shows the thermal stress which arises in the test body reinforced with the conventional method for comparing with this invention. It is a figure which shows the thermal stress which arises in the test body reinforced with the conventional method for comparing with this invention. It is a figure which shows the thermal stress which arises in the test body reinforced according to this invention. It is a figure which shows the thermal stress which arises in the test body reinforced according to this invention. It is a figure which shows the thermal stress which arises in the test body reinforced according to this invention. FIG. 17 (a) is a side view of a test body reinforced with a plurality of reinforcing plates according to the present invention, and FIG. 17 (b) is a cross-sectional view. It is a figure explaining the balance of the force of the horizontal direction of the micro section of the steel plate in the test body reinforced with a plurality of reinforcement boards according to the present invention. FIGS. 19 (a) and 19 (b) are diagrams showing the distribution of shear force generated in the adhesive of the test specimen reinforced by the conventional method for comparison with the present invention, and FIG. 19 (c) is according to the present invention. It is a figure which shows distribution of the shear force which arises in the adhesive agent of the reinforced test body. FIGS. 20 (a) and 20 (b) are diagrams showing the distribution of shear force generated in the adhesive of the test specimen reinforced according to the present invention. FIGS. 21A and 21B are diagrams showing the relationship between the number of layers in the test body reinforced in accordance with the present invention, the thermal stress, and the shearing force generated in the adhesive.

  Hereinafter, a steel structure reinforcing method and a steel structure reinforcing laminate according to the present invention will be described in more detail with reference to the drawings.

  Referring to FIGS. 1 (a) and 1 (b), according to the steel structure reinforcing method of the present invention, a steel structure that is a steel material having a predetermined thickness (T), for example, a thickness of 1 to 50 mm. The steel structure reinforcing material 100 is bonded to and integrated with the object 200 on at least one side of the steel material by an adhesive 110.

  The steel structure reinforcing material 100 includes a reinforcing fiber-containing material 1 having a sheet shape or plate shape having a smaller linear expansion coefficient than the steel material 200 constituting the steel structure, and an alloy plate 10 having a larger linear expansion coefficient than the steel material 200. Configured. The reinforcing material 100 is formed by bonding one member of the reinforcing fiber-containing material 1 or the alloy plate 10 to the surface of the steel material 200 with the adhesive 110, and then laminating the other member on the one member, If necessary, the members are alternately stacked and bonded with an adhesive 110. Alternatively, a predetermined number of layers of the reinforcing fiber-containing material 1 and the alloy plate 10 are alternately laminated with an adhesive 110 to be an integrated laminated material, and the reinforcing laminated material is adhered to the steel material surface with an adhesive. . FIG. 1A shows a mode in which the reinforcing fiber-containing material 1 is bonded to the steel surface, and FIG. 1B shows a mode in which the alloy plate 10 is bonded to the steel surface.

  The feature of the present invention is to reduce the thermal stress generated in the steel material 200 due to the temperature change and the thermal stress generated in the bonding interface between the steel structure reinforcing material 100 and the steel material 200. Therefore, the steel structure reinforcing material 100 having a laminated structure of the reinforcing fiber-containing material 1 and the alloy plate 10 is integrally bonded to the surface of the steel material with the adhesive 110, and the steel material 200, And the thermal stress which generate | occur | produces in the adhesion interface of the steel structure reinforcement material 100 and the steel material 200 is reduced.

  First, each material used in the present invention will be described.

(Steel structure reinforcement)
As described above, the steel structure reinforcing material 100 is laminated so that the reinforcing fiber-containing material 1 having a smaller linear expansion coefficient than that of the steel material and the alloy plate 10 having a larger linear expansion coefficient than that of the steel material are alternately included. Is done. Normally, steel materials have a linear expansion coefficient (αs) of 10 (μ / ° C.) ≦ αs ≦ 12 (μ / ° C.). Therefore, in the reinforcing fiber-containing material 1, the linear expansion coefficient (αft) of the reinforcing fiber itself contained is −15 (μ / ° C.) ≦ αft <αs, and the linear expansion coefficient (αfm) of the matrix resin itself is Usually, 30 (μ / ° C.) ≦ αfm ≦ 150 (μ / ° C.), but the linear expansion coefficient (αf) of the reinforcing fiber-containing material itself in the state of being impregnated and cured with the matrix resin is −15 (μ / ° C. ) ≦ αf <αs. Moreover, the thickness (tf) of the reinforcing fiber-containing material 1 is 0.1 to 2 mm. The alloy plate 1 has a linear expansion coefficient (αa) of αs <αa ≦ 30 (μ / ° C.) and a thickness (ta) of 0.5 to 5 mm. The layer thickness (ts) of the adhesive 110 is 100 to 1000 μm.

(1) Reinforcing fiber-containing material In the present invention, various forms of reinforcing fiber-containing material 1 can be used. Examples of the reinforcing fiber-containing material 1 will be described below as specific examples 1 to 3, but the form of the reinforcing fiber-containing material 1 used in the present invention is not limited to those shown in these specific examples.

Example 1
FIG. 2 shows an example of a reinforcing fiber-containing material 1 that can be used in the present invention. The reinforcing fiber-containing material 1 is a non-resin-impregnated fiber sheet 1A configured in a sheet shape by aligning continuous reinforcing fibers f in one direction. The fiber sheet 1A not impregnated with resin is impregnated with resin in the reinforcing step, and the thickness of the fiber sheet 1A is 0.1 to 0.3 mm. 1 A of fiber sheets are laminated | stacked and used as needed.

More specifically, the fiber sheet 1A can have a configuration in which a reinforcing fiber sheet composed of continuous reinforcing fibers f aligned in one direction is held by a wire fixing material 3 such as a mesh-like support sheet. . For example, when carbon fibers are used as the reinforcing fibers f, for example, a plurality of unimpregnated single fiber bundles in which 6000 to 24000 single fibers (carbon fiber monofilaments) f having an average diameter of 7 μm are converged in parallel in one direction. Used to align. The fiber basis weight of the carbon fiber sheet 1A is usually 30 to 1000 g / m ² .

  Carbon obtained by impregnating the surfaces of the warp yarn 4 and the weft yarn 5 constituting the mesh-like support sheet as the wire fixing material 3 in advance with a low melting point type thermoplastic resin, and arranging the mesh-like support sheet 3 in a sheet shape The fibers are laminated on one or both sides of the fiber and heated and pressed to weld the warp 4 and weft 5 portions of the mesh-like support sheet 3 to the carbon fiber sheet.

  In addition to the biaxial configuration, the mesh-shaped support sheet 3 is formed by orienting glass fibers in three axes, or only the wefts 5 orthogonal to the carbon fibers arranged in one direction. It can also be bonded to the so-called uniaxially oriented carbon fibers that are arranged and aligned in the form of a sheet.

  As the yarn of the wire fixing material 3, for example, a double-structured composite fiber having a glass fiber in the core and a low-melting-point heat-fusible polyester around it is also preferably used. .

Example 2
Further, as shown in FIG. 3, the reinforcing fiber-containing material 1 is formed by laminating one or a plurality of reinforcing fiber sheets in which a plurality of reinforcing fibers f are aligned in one direction, for example, a fiber sheet 1A as shown in FIG. Then, a plate-like fiber reinforced resin plate (hereinafter referred to as “FRP plate”) 1B impregnated with resin Re and cured with the resin may be used. Usually, the fiber reinforced resin plate 1B has a thickness of 0.1 to 2 mm, but is not limited thereto.

  In the fiber sheet 1A and the fiber reinforced resin plate 1B described in the specific examples 1 and 2, the reinforcing fiber f is not limited to the carbon fiber, and other inorganic fibers such as glass fiber and basalt fiber, Organic fibers such as aramid fibers, PBO (polyparaphenylene benzbisoxazole) fibers, polyamide fibers, polyarylate fibers, and polyester fibers can be used alone or in a mixture of plural kinds.

  In addition, as the resin Re in the case of the fiber reinforced resin plate 1B in the specific example 2, a thermosetting resin or a thermoplastic resin can be used. As the thermosetting resin, a room temperature curing type or a thermosetting type can be used. Epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, phenol resin, or the like is preferably used, and nylon, vinylon, or the like can be preferably used as the thermoplastic resin. The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

Example 3
Further, as shown in FIG. 4 and FIG. 5, the reinforcing fiber-containing material 1 has a plurality of small continuous fiber reinforced plastic wires 2 impregnated with a matrix resin R and cured, and is formed in a slender shape in the longitudinal direction. It is also possible to use a fiber sheet 1 </ b> C in which the wire rods 2 are aligned and fixed to each other with a wire rod fixing material 3.

  The fiber reinforced plastic wire 2 has a substantially circular cross-sectional shape (FIG. 5A) having a diameter (d) of 0.5 to 3 mm, or a width (w) of 1 to 10 mm and a thickness (t) of 0. A substantially rectangular cross-sectional shape (FIG. 5B) of 1 to 2 mm can be obtained. Of course, other various cross-sectional shapes can be used as necessary.

  As described above, in the fiber sheet 1 </ b> C that is aligned and slid in one direction, the wires 2 are close to and separated from each other by a gap (g) = 0.05 to 3.0 mm. Fixed. In addition, the length (Lf) and width (Wf) of the fiber sheet 1C formed in this way are appropriately determined according to the size and shape of the structure to be reinforced, The total width (Wf) is 100 to 1000 mm. Further, the length (Lf) can be a strip of about 1 to 5 m, or a length of 100 m or more.

  It is also possible to manufacture the fiber sheet 1C with a length (Lf) of about 1 to 5 m and a width Wf of about 1 to 10 m longer than this. The thickness tf of the fiber sheet 1C is 0.1 to 2 mm, but is not limited to this.

  Also in the case of the fiber sheet 1C, the reinforcing fiber f includes inorganic fibers such as carbon fiber, glass fiber, and basalt fiber, and further, aramid, PBO (polyparaphenylene benzbisoxazole), polyamide, polyarylate, polyester, and the like. The organic fibers can be used alone or in a hybrid mixed with a plurality of types. The matrix resin R impregnated in the fiber reinforced plastic wire 2 can be a thermosetting resin or a thermoplastic resin. As the thermosetting resin, a room temperature curing type or a thermosetting type epoxy resin, A vinyl ester resin, an MMA resin, an acrylic resin, an unsaturated polyester resin, a phenol resin, or the like is preferably used, and nylon, vinylon, or the like can be preferably used as the thermoplastic resin. The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

  Further, as a method of fixing each wire 2 with the wire fixing material 3, for example, as shown in FIG. 4, a plurality of wires arranged in a sag-like manner using wefts as the wire fixing material 3 are arranged. It is possible to adopt a method of driving and knitting a wire rod in the form of a sheet consisting of two, that is, a continuous wire rod sheet at a constant interval (P) perpendicular to the wire rod. The driving interval (P) of the weft yarn 3 is not particularly limited, but is usually selected in the range of 10 to 100 mm in consideration of the handleability of the produced fiber sheet 1.

  At this time, the weft 3 is, for example, a yarn obtained by bundling a plurality of glass fibers or organic fibers having a diameter of 2 to 50 μm. Moreover, nylon, vinylon, etc. are used suitably as an organic fiber.

  As another method of fixing each wire 2 in a slender shape, a mesh-like support sheet can be used as the wire fixing member 3 as shown in FIG.

  That is, the above-mentioned specific example in which a plurality of wire rods 2 arranged in the form of a sheet in a sheet form, that is, one side or both sides of a wire sheet is made of glass fiber or organic fiber having a diameter of 2 to 50 μm, for example. 1 may be configured to be supported by a mesh-like support sheet 3 having the same configuration as described in 1.

  Furthermore, as another method of fixing each wire 2 in a slender shape, as shown in FIG. 6 (b), as the wire fixing material 3, for example, a flexible belt material such as an adhesive tape or an adhesive tape is used. Can be used. The flexible strip 3 has one side or both sides of a plurality of fiber reinforced plastic wires 2 in a direction perpendicular to the longitudinal direction of each fiber reinforced plastic wire 2 arranged in the form of a sheet. Paste and fix.

  That is, as the flexible strip 3, an adhesive tape or adhesive tape such as a vinyl chloride tape, a paper tape, a cloth tape, and a nonwoven fabric tape having a width (w1) of about 2 to 30 mm is used. These tapes 3 are usually stuck in a direction perpendicular to the longitudinal direction of each fiber reinforced plastic wire 2 at intervals (P) of 10 to 100 mm.

  Furthermore, as the flexible strip 3, the thermoplastic resin such as nylon or EVA resin is formed into a strip and is heat-bonded to one side or both sides in the direction perpendicular to the longitudinal direction of the wire 2. Is done.

(2) Alloy plate The alloy plate 10 constituting the reinforcing material 100 shown in FIGS. 1 and 2 is an aluminum alloy, a stainless alloy, a magnesium alloy, or the like. As shown in FIG. 7, the length (La) and width (Wa) of the alloy plate 10 are appropriately determined according to the size and shape of the steel structure 200 to be reinforced. The thickness (ta) of the alloy plate 10 is 0.5 to 5 mm, but is not limited to this thickness.

(3) Adhesive The adhesive 110 for adhering the reinforcing material 100 to the steel surface and the adhesive 110 for adhering the reinforcing fiber-containing material 1 and the alloy plate 10 are a matrix resin impregnated in the reinforcing fiber-containing material 1. And a thermosetting resin or a thermoplastic resin can be used. For example, as the thermosetting resin, room temperature curing type or thermosetting type epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, phenol resin, etc. are preferably used, and thermoplasticity is also used. As the resin, nylon, vinylon and the like can be suitably used. As described above, the layer thickness (ts) of the adhesive 110 is in the range of 100 to 1000 μm.

(Reinforcing method)
According to the present invention, the reinforcing fiber-containing material 1 and the alloy plate 10 configured as described above are alternately bonded while being laminated on the surface of the steel structure 200, or the reinforcing fiber-containing material 1 and the alloy plate 10 are bonded. The reinforcing laminate 100, which is previously laminated and integrated with an adhesive, is used as the reinforcing member 100, and the reinforcing laminate 100 is adhered to the surface of the steel structure 200 to reinforce the steel structure 200. it can.

  Specific examples 1 and 2 of an embodiment of a steel structure reinforcing method according to the present invention will be described.

Example 1
According to the method for reinforcing a steel structure of the present invention, for example, as the reinforcing fiber-containing material 1, the fiber sheet 1A produced by aligning the reinforcing fibers f described in the reinforcing fiber-containing material specific example 1 in one direction is used. It can be used, and is bonded and integrated with the adhesive 110 on the surface of the steel structure 200.

  When reinforcing the steel structure 200, for members (structures) that mainly receive bending moment and axial force, the orientation direction of the reinforcing fibers is generally aligned with the principal stress direction of tensile stress or compression stress generated by the bending moment. By bonding, it is possible for the fiber sheet 1A to effectively bear the stress and to efficiently improve the load resistance of the structure.

  When bending moments act in two orthogonal directions, two or more layers of fiber sheets 1A are orthogonally bonded so that the orientation direction of the reinforcing fibers f of the fiber sheet 1A substantially matches the principal stress generated by the bending moment. By doing so, the load bearing capacity can be improved efficiently.

  Next, with reference to FIG. 8, the specific example 1 of the reinforcement method of the steel structure which concerns on this invention is further demonstrated.

(First step)
As shown in FIGS. 8A and 8B, the weakened portion 201a of the surface to be reinforced (that is, the surface to be bonded) 201 of the steel structure 200 is ground with a disk sander, sandblast, steel shot blast, water jet or the like. The substrate 50 is removed by the means 50 and the surface to be bonded 201 of the steel structure 200 is subjected to a ground treatment so as to become a surface 202 having an appropriate roughness.

(Second step)
An epoxy resin primer 203 is applied to the surface 202 subjected to the ground treatment (FIG. 8C). The primer 203 is appropriately selected according to the material of the steel structure to be reinforced 200 such as MMA resin without being limited to the epoxy resin system.

  In addition, the application | coating process of the primer 203 can also be skipped.

(Third step)
Next, as shown in FIG. 8 (d 1), the adhesive 110 is applied on the surface of the steel material, and the fiber sheet 1 A is pressed against this surface to adhere the fiber sheet 1 A to the surface 202 of the steel structure 200 to be reinforced. In this example, since the fiber sheet 1A not impregnated with resin is used, a part of the adhesive (resin) is impregnated into the fiber sheet 1A as a matrix resin. Of course, the fiber sheet 1A impregnated with resin may be pressed and adhered on the steel structure surface 202 on site.

  As described above, the amount of resin impregnation into the fiber sheet 1A is 30 to 70% by weight, preferably 40 to 60% by weight.

  Thereafter, as shown in FIG. 8 (e1), an adhesive 110 is additionally applied on the fiber sheet 1A (that is, the reinforcing fiber-containing material 1) impregnated with the resin, if necessary, For example, the aluminum alloy plate 10 is pressed and bonded.

  As another method, as shown in FIG. 8 (d2), an adhesive 110 is applied onto the steel surface 202, and an alloy plate 10 such as an aluminum alloy plate is first pressed against this surface to reinforce the steel to be reinforced. The alloy plate 10 is bonded to the surface 202 of the structure 200. Thereafter, as shown in FIG. 8 (e2), the adhesive 110 is applied on the alloy plate 10, and the fiber sheet 1A is pressed and bonded thereon. Of course, the fiber sheet 1A impregnated with the resin may be pressed onto the alloy plate 10 and bonded.

  As the adhesive 110 used, the same one as the matrix resin impregnated in the fiber sheet 1A is used, and in particular, a room temperature curing type epoxy resin, an epoxy acrylate resin, an acrylic resin, an MMA resin, a vinyl ester resin, Examples thereof include unsaturated vinyl ester resins and photo-curing resins, and specifically, room-temperature curing epoxy resins and MMA resins are suitable. In this example, an epoxy resin was used.

  As shown in FIGS. 8 (f1) and (f2), a reinforcing material 100 having a two-layer structure configured by laminating at least one layer of the reinforcing fiber-containing material 1 and the alloy plate 10 on the steel material surface 202 by the reinforcing operation. Are integrally bonded, and the steel structure 200 is reinforced.

  Further, as shown in FIGS. 8 (g1) and (g2), the reinforcing fiber-containing material 1 and the alloy plate 10 are alternately laminated as described above by alternately laminating the reinforcing fiber-containing material 1 or the alloy plate 10 as necessary. The steel material can be reinforced by the reinforcing material 100 provided with a plurality of layers 10.

  Moreover, in the description of the above-described specific example 1 of the reinforcing method, the reinforcing material-containing material 1 and the alloy plate 10 are alternately reinforced with the reinforcing material 100 while being laminated on the steel material surface with an adhesive. However, as shown in FIG. 9A, a laminate in which the reinforcing fiber-containing material 1 and the alloy plate 10 are integrally bonded to each other with an adhesive 110 is formed in advance, and a reinforcing material (reinforcing material) made of this laminate is formed. As shown in FIG. 9 (d11), the adhesive layer 110 is applied to the steel material surface 202 and the reinforcing fiber-containing material 1 side of the reinforcing material 100 is adhered to the laminated material 100, or as shown in FIG. 9 (d12). ), The reinforcing plate 100 can be bonded by pressing the alloy plate 10 side. At this time, the reinforcing fiber-containing material 1 constituting the reinforcing laminate 100 is usually a fiber-reinforced resin plate (that is, FRP plate) 1B impregnated and cured with resin, but the fiber sheet not impregnated with resin. 1A may be sufficient. In the case of the resin unimpregnated fiber sheet 1A, the adhesive is impregnated into the fiber sheet 1A as a matrix resin at the time of adhesion.

Example 2
In the above-described specific example 1 of the reinforcing method, the aspect in which the reinforcing material 100 having the two-layer structure constituted by the reinforcing fiber-containing material 1 and the alloy plate 10 is bonded to the steel material surface 202 to be reinforced is described. The laminated structure of the reinforcing material is not limited to this.

  For example, as shown in FIG. 8 (g1), the reinforcing material 100 laminated on the surface of the steel material can also have a three-layer configuration of the reinforcing fiber-containing material 1, the alloy plate 10, and the reinforcing fiber-containing material 1. The cured fiber-containing material 1 is bonded to the steel material surface 202.

  Furthermore, as shown in FIG. 8 (g2), the reinforcing material 100 laminated on the steel material surface can also have a three-layer structure of the alloy plate 10, the reinforcing fiber-containing material 1, and the alloy plate 10, in this case, The alloy plate 10 is bonded to the steel material surface 202.

  The reinforcing fiber-containing material 1 or the alloy plate 10 can be further stacked on the reinforcing material 100 having the laminated structure. The number of layers (N) is appropriately determined depending on the degree of steel plate reinforcement required.

  According to the reinforcing method of the present invention configured as described above, the linear expansion coefficient of the reinforcing material 100 in which the reinforcing fiber-containing material 1 and the alloy plate 10 are bonded and integrated is brought close to the linear expansion coefficient of the steel plate 200. The thermal stress generated in the steel plate 200 to which the reinforcing material 100 is bonded and the thermal stress generated at the bonding interface between the reinforcing material 100 and the steel plate 200 can be reduced. This point will be described in detail next.

  In general, in the reinforcing fiber-containing material 1 impregnated with resin (matrix resin), that is, a fiber-reinforced resin plate (FRP plate), the linear expansion coefficient of the FRP plate is arbitrarily set by changing the reinforcing fiber content rate. be able to.

  However, the reinforcing fiber-containing material (FRP plate) 1 has a very small Young's modulus of the matrix resin as compared with the reinforcing fiber. Therefore, when the linear expansion coefficient of the FRP plate is set to the same level as that of steel, the fiber content is reduced. The mechanical properties become poor. Therefore, as a method of reducing the thermal stress generated in the steel plate and the thermal stress generated at the bonding interface between the FRP plate and the steel plate, in the present invention, in addition to the FRP plate 1, for example, Young's modulus 70 GPa, linear expansion coefficient 23 μ / ° C. An alloy plate 10 such as an aluminum alloy plate is bonded to the steel plate 200.

  That is, by making the linear expansion coefficient of the reinforcing material (reinforcing laminated material) 100 in which the FRP plate 1 and the alloy plate 10 are bonded and integrated close to the linear expansion coefficient of the steel plate 200, The thermal stress generated in the steel plate 200 to which the laminated material (reinforcing material) 100 is bonded and the thermal stress generated in the bonding interface between the reinforcing material 100 and the steel plate 200 can be reduced.

  The linear expansion coefficient αν of the reinforcing member 100 in which the FRP plate 1 and the alloy plate 10 are bonded together is given by the following equation from the balance of internal forces due to thermal expansion and contraction of each FRP plate 1 and each alloy plate 10.

Αν in equation (1) is replaced with the linear expansion coefficient α _s of steel, and the following equation is obtained by solving for the elongation stiffness ratio E _a A _a / (E _f A _f ) of the alloy plate 10 with respect to the FRP plate 1.

  By substituting the linear expansion coefficients of steel, FRP plate and alloy plate into this formula (2), the linear expansion coefficient of the reinforcing material 100 of the FRP plate 1 and the alloy plate 10 is made equal to that of the steel plate 200. The elongation rigidity of the alloy plate 10 with respect to the elongation rigidity can be designed.

  As understood from the above, when a plurality of FRP plates and alloy plates (N layers) are laminated, the above formulas (1) and (2) are generalized, and the following formula (1-1), It can be expressed as (2-1).

  Each of the above formulas is an equation for obtaining the thickness and width of each layer of the laminated plate necessary to make the thermal expansion coefficient of the laminated plate constituting the reinforcing material 100 equal to the thermal expansion coefficient of the steel material to be reinforced, The thickness and width of each layer of the laminate are not limited to this. If the thickness and width of each layer obtained from these formulas are used, theoretically no thermal stress is generated, but this is not the only case, and the thermal expansion coefficient of steel is lower than that of reinforcing only FRP plates having a smaller thermal expansion coefficient than steel. If a large alloy plate is combined, thermal stress is relieved.

  The following tests were conducted in order to demonstrate the operational effects of the structure reinforcing method according to the present invention. Hereinafter, this test example will be described.

  In the reinforcing method of the present invention, carbon fiber is typically used as the reinforcing fiber of the reinforcing fiber-containing material 1, so that the reinforcing fiber-containing material 1 in this test example has been described as specific example 2. The carbon fiber reinforced resin plate (CFRP plate) 1B using carbon fiber as the reinforcing fiber and epoxy resin as the impregnating resin was used. In addition, since an aluminum alloy plate (AL plate) is typically used as the alloy plate 10 in the reinforcing material 100, the test was performed using an AL plate in this test example.

(Test example)
(1) Test conditions
When the two CFRP plates with Young's modulus of 140 GPa, thickness of 1 mm, and width of 25 mm are respectively bonded to the upper and lower surfaces of the steel sheet having a thickness of 4.5 mm and a width of 25 mm shown in FIG. As an object (comparative example), the thermal stress reduction effect in the reinforcing method according to the present invention will be clarified.

In order to make the reinforcing effect of the steel plate constant, the elongation stiffness of the sum of the CFRP plate and the AL plate is designed to be the same as the elongation stiffness of the CFRP plate of FIG. In order to design the elongation rigidity of the AL plate to be bonded, the linear expansion coefficient α _s of the steel plate, the linear expansion coefficient α _f of the CFRP plate, and the linear expansion coefficient α _a of the AL plate are respectively set to α _s = 12 μ / ° C., α _f = 1 μ / ° C. and α _a = 23 μ / ° C. By substituting those values into the equation (2), E _a A _a / (E _f A _f ) = 1 is obtained.

  Therefore, by making the elongation rigidity of the AL plate equal to that of the CFRP plate, the linear expansion coefficient of the composite plate of the CFRP plate and the AL plate can be made equal to that of the steel plate. That is, with respect to FIG. 10A, one CFRP plate out of two CFRP plates bonded to one side of a steel plate is replaced with an AL plate having the same elongation rigidity. Since the Young's modulus of the AL plate is 70 GPa (1/2 times that of the CFRP plate), the cross section of the AL plate that reduces thermal stress is twice that of the CFRP plate. FIGS. 10B, 10C, and 10D show the steel plates to which the CFRP plate and the AL plate are bonded in this way.

  The test body ACA in FIG. 10D is a three-layer laminate in which a CFRP plate is bonded between AL plates each having a thickness of 1 mm.

  In addition to the specimens of FIGS. 10 (b), (c), and (d), a specimen CC in which two CFRP plates shown in FIG. 10 (a) are bonded, and although not shown, A temperature change test was also performed on the test body AA in which two AL plates each having a thickness of 2 mm were mounted on both sides. Although not shown in the figure, the three-layer structure is the same as that of the test body ACA in FIG. 10 (d), but a three-layer laminate in which an AL plate having a thickness of 2 mm is bonded between each CFRP plate having a thickness of 1 mm. A temperature change test of the test body CAC to be a plate was also performed.

  In the reinforcing method in which the reinforcing material is reinforced by bonding the reinforcing material to the object to be reinforced as in the present invention, the mutual force between the steel plate and the CFRP plate or the AL plate is transmitted via the adhesive. Therefore, it is necessary to design the bonding length so that the force transmission between the steel plate, the CFRP plate and the AL plate is sufficiently performed. In this test example, the CFRP plate and the CFRP plate The length of the AL plate was 100 mm (the length of the steel plate was 160 mm).

  Each adhesive surface of the steel plate, CFRP plate and AL plate was polished with # 100 sandpaper, wiped off the fats and oils, and then adhered with an adhesive. After bonding CFRP plate and AL plate to one side of steel plate and curing at room temperature of 20 ° C for one day, CFRP plate and AL plate are bonded to the other side in the same way, and at room temperature of 20 ° C for one week or more. Cured.

  Table 1 shows the dimensions of the measured specimens. The thickness of each material is shown in the material constants in Table-2. The thickness of the adhesive shows the average thickness divided by the number of adhesive layers by subtracting the thickness of the steel plate and the CFRP plate and AL plate that were bonded from the total thickness of the specimen measured with calipers. Yes.

  In FIG. 11, the position of the strain gauge affixed on the test body is shown. Strain gauges having a linear expansion coefficient set to 11.7 μ / ° C. are affixed to both side surfaces of the steel plate and both surfaces of the CFRP plate or AL plate adhered to the outermost surface.

Steel used for the characteristic test of the material used in the test body, CFRP plate, the material constant of AL plate and adhesives shown in Table 2. The steel plate, the CFRP plate, and the AL plate show values obtained from a tensile test and a test given a temperature change. The material constant of the adhesive is the compression modulus and Poisson obtained from the compression test (20 ° C.) of a cube (14 mm on one side) made with the adhesive used in the test specimen, in addition to the values in the material test report. The ratio is also shown.

  The linear expansion coefficients of the steel plate, the CFRP plate, and the AL plate were calculated from the strains generated in the unconstrained steel plate, the CFRP plate, and the AL plate using the following formula in a temperature change test described later.

ε _g (T) [μ] is an approximate expression of the apparent strain of the self-temperature compensated strain gauge, and the coefficient varies depending on the production lot.

From Tables 1 and 2, it can be seen that the Young's modulus and each linear expansion coefficient of the steel plate, CFRP plate, and AL plate used for the test specimens are comparable to the values of the respective materials assumed in the design. Table 1 shows the linear expansion coefficient αν of a synthetic plate (reinforcing material) composed of a CFRP plate and an AL plate calculated by substituting the measured dimensions and material constants of Tables 1 and 2 into Equation (1). It can be seen that for the test specimens CA, AC and ACA, the linear expansion coefficient αν of the composite plate (reinforcing material) is close to the linear expansion coefficient α _s of steel.

Test Method In this test example, a temperature change test was performed using a drying furnace. The test body was suspended vertically in a drying furnace and left in a constant temperature room at 20 ° C. for about 2 hours with the door opened. After that, the strain is measured, the door of the drying furnace is closed, the set temperature in the furnace is raised to 40 ° C., the temperature is kept until there is no fluctuation of each strain, the strain is measured, and the test for the temperature rise is performed. did. Furthermore, the door of the drying furnace was opened from that state, and the temperature was lowered to 20 ° C. Similarly, after the fluctuation of each strain disappeared, the strain was measured and used as a test against the temperature drop. In addition to each specimen, unconstrained steel plates, CFRP plates, and AL plates were similarly subjected to temperature changes to measure strain. The temperature of the test body was measured using a thermocouple. Table 1 shows actually measured temperatures T1 and T2 at the start and end of the test.

(2) (Test results)
Using the measured strain occurring on the steel sheet epsilon _sm and distortion occurring steel unrestrained epsilon _sn and steel Young's modulus E _s, were calculated thermal stress sigma _s caused steel from the following equation.

Similarly, the thermal stresses σ _f and σ _a of the outermost CFRP plate or AL plate were calculated using the strain generated in the CFRP plate or AL plate of the test specimen and the strain generated in the unconstrained CFRP plate or AL plate. .

  The thermal stress which arises in each test body at the time of temperature rise and fall is shown to FIG. 12 (a), (b)-FIG. 16 (a), (b), respectively.

  The thermal stress generated in the steel plate indicates an average value on both side surfaces of the steel plate, and the thermal stress generated on the CFRP plate and the AL plate indicates an average value on the upper and lower surfaces. The horizontal axis in the figure indicates the distance x (see FIGS. 10A to 10D) from the center of the bonding length of the CFRP plate and the AL plate. In FIGS. 12A and 12B to FIGS. 16A and 16B, “numerical analysis results” described later are also indicated by solid lines and broken lines.

  As can be seen from FIGS. 12 (a), 12 (b) to 16 (a), (b), the thermal stresses generated at the time of temperature rise and fall are different in sign only, and their absolute values are substantially equal.

From FIGS. 12 (a), 12 (b) and 13 (a), 13 (b), when the temperature rises, in the test body CC to which only the CFRP plate is bonded and the test body AA to which only the AL plate is bonded, the compressive stress It can be seen that tensile stress is generated. At the end of the CFRP plate or the AL plate, those values are small, and a large tensile stress or compressive stress is generated at the position of x = 0. The thermal stress generated in the steel plate and the CFRP plate at the position of x = 0 is a value σ _sT calculated by substituting the measured dimensions and material constants in Tables 1 and 2 into the following formula derived from the balance of internal force of the member. It almost coincides with σ _fT (■ in the position of x = 0 in the figure).

By replacing the cross section A _f and material constants E _f and α _f of the CFRP plates of the formulas (6) to (8) with the A _a , E _a and α _f of the AL plate, respectively, the steel plate and the AL plate of the specimen AA The convergence values σ _sT and σ _{aT of the} thermal stress generated in can be calculated.

  14 (a), 14 (b) to 16 (a), 16 (b), in the test bodies CA, AC, and ACA, the thermal stress generated in the steel plate at the position of x = 0 is almost zero. Recognize. In the test bodies CA and AC, a slight thermal stress is generated in the steel plate near the end of the reinforcing plate. However, in the test body ACA, the thermal stress generated in the steel plate is also reduced in the vicinity of the bonded end.

  Therefore, by bonding the CFRP plate and the AL plate so as to satisfy the ratio of the elongation stiffness of the AL plate to the elongation stiffness of the CFRP plate calculated by the equation (2), the thermal stress generated in the steel plate is greatly reduced. be able to.

On the other hand, from FIGS. 14 (a), (b) to 16 (a), (b), the thermal stress generated in the outermost CFRP plate or AL plate of the test bodies CA, AC, and ACA is the test body CC (see FIG. 12) or thermal stresses σ _f and σ _a generated in the specimen AA (FIG. 13). This is because the difference in the linear expansion coefficient between the CFRP plate and the AL plate is larger than the difference in the linear expansion coefficient between the steel plate and the CFRP plate or between the steel plate and the AL plate.

The thermal stress generated in the steel plate, the CFRP plate, and the AL plate at the position x = 0 of the test specimens CA, AC, and ACA is expressed in the following formula derived from the balance of the internal forces of the steel plate, the CFRP plate, and the AL plate. The values σ _sT , σ _fT, and σ _aT (■ at the position of x = 0 in the figure) calculated by substituting the measurement dimensions and material constants of 2 are almost the same.

To the test body ACA, the cross-sectional area A _a of AL plate gave the sum of the cross-sectional area of the two AL plate.

(3) (Numerical analysis)
Next, when two or three CFRP plates and an AL plate are bonded to the upper and lower surfaces of the steel sheet, the literature “Takeshi Miyashita, Masami Nagai: Stress of a steel sheet laminated with multilayer CFRP subjected to uniaxial tension. Analysis, JSCE Paper A, Vol. 66, No. 2, pp. 378-392, 2010 ”was used to calculate the thermal stress generated in the steel plate, CFRP plate, and AL plate by numerical analysis. As shown in FIG. 17, from the side close to the steel plate, the reinforcing plates which are CFRP plates or AL plates are numbered as reinforcing plates 1, 2,.

Analysis Method The relationship between the stress σ _s (x) and the strain ε _s (x) generated in the steel plate and the relationship between the stress σ _i (x) and the strain ε _i (x) generated in the reinforcing plate i are given by the following equations, respectively.

The relationship between the shear stress τ _i (x) generated in the adhesive i and the shear strain γ _i (x) is given by the following equation.

  Expressions (14), (15), and (18) are expressed in matrix / vector format as follows.

  The matrix / vector format of the relational expression of the strain to be derived is given by the following equation from the balance of the forces in the horizontal direction of the minute section of the steel plate to which a plurality of reinforcing plates are bonded as shown in FIG.

The general solution of equation (24) is given by:

The undetermined coefficient vector C is determined by giving boundary conditions. With respect to the steel plate to which a plurality of reinforcing plates shown in FIG. 17 are bonded, the stress σ _s (x) generated in the steel plate is equal to the acting stress σ _sn at the end of the reinforcing plate, and the stress σ _i ( x) is all 0, and further, a boundary condition is given in which the shear stress τ _i (x) generated in each adhesive is 0 at the center of attachment (x = 0) of the reinforcing plate. Is calculated by

  Therefore, when a plurality of reinforcing plates are bonded, the undetermined coefficient vector calculated from the equation (31) is substituted into the equation (26), and from the equation (19), the steel plate, each reinforcing plate, and each adhesive. Can be calculated by numerical analysis.

Numerical analysis results (1) Stress generated in steel sheet The numerical analysis results calculated by giving the dimensions and material constants of the specimens in Tables 1 and 2 are shown in FIGS. 12 (a), 12 (b) to 16 (a), ( It is indicated by a solid line and a broken line in b). Since the analysis value does not include the influence of the resin forming the CFRP plate, it becomes slightly larger than the experimental value in the vicinity of the bonded end portion, but it can be seen that both show the same tendency.

  As shown in FIGS. 14 (a), 14 (b) to 16 (a), (b), it is possible to evaluate the thermal stress slightly generated in the steel plates at the bonded ends of the test bodies CA, AC, and ACA by analysis. I understand that. At the time of temperature rise, in the test body CA, the thermal stress of the steel plate at the bonded end is compression, but in the test body AC, tension is generated. This is because the axial force is transmitted from the steel plate to the reinforcing plate 1 and then the axial force is transmitted from the reinforcing plate 1 to the reinforcing plate 2, so that the steel plate near the bonded end is reinforced compared to other reinforcing plates. This is because it is greatly affected by the linear expansion coefficient of the plate 1.

  Further, in the analysis results, the thermal stress generated in the steel plate at the bonded end of the three-layer test body ACA was smaller than that of the test bodies CA and AC, and showed the same tendency as the experimental results.

  As for the stress generated in the CFRP plate or the AL plate, the analytical value and the experimental value almost coincide with each other at the position of x = 0, but in the specimens CA, AC and ACA, in the vicinity of the bonded end (x = 45 mm), There was a difference between the two values. This is due to the fact that the bending moment generated at the bonded end of the CFRP plate and the AL plate is not taken into account because this analysis is a method that handles only the axial force. Since no bending moment is generated in the steel plate, it is considered that the influence of the bending moment generated at the bonded end of the CFRP plate and the AL plate on the thermal stress of the steel plate is small. However, since a vertical stress is generated in the adhesive due to the bending moment generated near the bonded end of the CFRP plate or AL plate, it is necessary to clarify the bending moment generated in the peeling of the CFRP plate or AL plate when evaluating the peeling. It is believed that there is.

(2) Shear stress generated in the adhesive The distribution of the shear stress generated in the adhesive of each specimen with respect to the temperature rise, obtained by numerical analysis, is shown in FIGS. 19 (a), 19 (b), 19 (c) and FIG. Shown in a) and (b).

  As can be seen from these figures, in the test specimens CC and AA, the signs of the shear stress generated in each adhesive are equal, and the absolute value of the shear stress generated in the adhesive 1 close to the steel plate is larger than that of the adhesive 2. . On the other hand, in the test bodies CA and AC, the signs of the shear stress generated in the adhesives 1 and 2 are different, and the absolute value of the shear stress generated in the adhesive 2 is larger than that of the adhesive 1.

  Further, the absolute value of the shear stress generated in the adhesive 2 of the test specimens CA and AC is larger than the absolute value of the shear stress generated in the adhesive 1 of the test specimens CC and AA. In the test body ACA, the signs of the shear stress generated in the adhesives 1 and 3 are equal, and the absolute value of the shear stress generated in the adhesive 3 is maximized.

  Furthermore, the absolute value of the shear stress generated in the adhesive 3 of the test body ACA is smaller than the absolute value of the shear stress generated in the adhesive 1 of the test bodies CC and AA.

  These phenomena depend on the difference in the coefficient of linear expansion between the steel plate and the CFRP plate, the steel plate and the AL plate, the CFRP plate and the AL plate, and the elongation rigidity of each material.

  As described above, the surface strain near the bonding edge of the outermost CFRP plate or AL plate measured in the experiment is affected by the bending moment. The generated shear stress cannot be calculated, but the shear stress generated in the adhesive 1 can be calculated by using the measured value of the steel plate stress that does not generate the bending moment.

  There is the following relationship between the shear stress generated in the adhesive 1 and the steel plate stress.

  When this expression is expressed in the form of a difference, the following expression is obtained.

  19 (a), (b), (c) and FIG. 20 (a) show the shear stress τ1 generated in the adhesive 1 by receiving the temperature change from the equation (34) using the thermal stress of the steel plate of each specimen. (B). Since the number of measurement points of strain generated in the steel sheet is small and the interval between them is large, an accurate value is not obtained. From these figures, the shear stress generated in the adhesive 1 calculated from the experimental value is the analytical value. It turns out that the same tendency is shown.

  Furthermore, it is clear from the experimental values that the shear stress generated in the adhesive 1 of the test body ACA laminated in three layers is most reduced.

(3) Effect of CFRP plate and AL plate lamination number on thermal stress and shear force As a result of numerical analysis on the CFRP plate and AL plate lamination number N, the number of laminations is an even number (N = 2) as described above. In the case of), in the case where the reinforcing plate close to the steel plate is a CFRP plate and in the case of the AL plate, the thermal stress generated in the steel plate and the shear stress generated in the adhesive have the same absolute value but different signs. Similarly, even when the number of stacked layers is an odd number (N = 3), although not shown in FIGS. 19 and 20, the heat generated in the steel plate when the reinforcing plate close to the steel plate is a CFRP plate and the AL plate is used. The absolute values of the stress and the shear stress generated in the adhesive are the same except for the signs.

  Therefore, numerical analysis was performed for the case where the CFRP plate and the AL plate were bonded to the steel plate so that the first layer was a CFRP plate with respect to the number of stacked layers N = 4 or more.

Under the conditions where the theoretical analysis and the numerical analysis were performed, the thermal stress generated in the steel sheet was almost 0 except in the vicinity of the end of the CFRP plate. Therefore, FIG. 21A shows the relationship between the maximum value σ _{sT of the} thermal stress generated in the steel plate in the vicinity of the end portion of the CFRP plate and the number N of layers, except for the case of N = 1. N = 1 in the figure indicates the thermal stress σ _s (0) (where σ _sn = 0) generated in the middle steel plate of the bonding length of the CFRP plate when one layer of the CFRP plate is bonded to the steel plate, The vertical axis represents the value obtained by dividing σ _s T by σ _s (0). From this figure, the maximum value σ _sT of the thermal stress generated in the steel plate near the end of the CFRP plate shows a slight increasing tendency when the number of laminations N is an even number, but decreases with an increase in the number of laminations. I understand.

FIG. 21B shows the relationship between the peeling shear stress τ _ei generated in each adhesive and the number N of layers. As the temperature rises or falls, the peeling shear stress generated in each adhesive alternates between positive and negative. Therefore, the vertical axis of the figure shows the peeling shear stress τ _ei of each adhesive, and N = 1, that is, the peeling shear stress τ (l) generated in the adhesive when one layer of CFRP plate is bonded to the steel plate (where, The absolute value of the value divided by σ _sn = 0) is shown. From FIG. 21B, when the adhesive layer is 2, the absolute value of the shear stress generated in the adhesive 2 due to the temperature change is determined from the peeling shear stress τ (l) generated when the single layer of CFRP plate is bonded to the steel plate. However, when the adhesive layer is 3 or more, the absolute value of the peeling shear stress caused by the temperature change is always smaller than the absolute value of τ (l) by bonding the AL plate and the CFRP plate. .

  It can be seen that in the adhesive 1 in which the peeling shear stress becomes the largest when the tensile stress is applied, the absolute value of the peeling shear stress caused by the temperature change is greatly reduced by bonding the CFRP plate and the AL plate. Since the difference in coefficient of linear expansion between the CFRP plate and the AL plate is larger than that between the CFRP plate and steel, the absolute value of the peeling shear stress generated in the adhesives 2 to 7 between the AL plate and the CFRP plate is the peeling value of the adhesive 1. The shear stress is always greater than the absolute value of the shear stress, and the shear stress generated in the adhesive of the outermost layer is always maximized for each number N of layers.

  The peeling shear stress generated in each adhesive due to temperature change tends to decrease as the number of laminations N increases. However, when the number of laminations N is an even number, the peeling shear stress generated in each adhesive is an odd number of laminations N. It is slightly larger than the drop in the case of. This phenomenon was also obtained from the results of FEM analysis. When the number N of layers is an even number, a member having a linear expansion coefficient equal to that of a steel plate is formed for each CFRP plate and AL plate of each layer, as shown in FIGS. 21 (a) and (b), It is thought that the maximum value of the thermal stress generated in the steel sheet and the peeling shear stress generated in the adhesive were affected.

  As described above, the AL plate and the CFRP plate are bonded symmetrically to the upper and lower surfaces of the steel plate so that the number N of laminations is 3 or more, so that the thermal stress generated in the steel plate and the peeling shear stress generated in the adhesive due to temperature change It has been clarified that this can be reduced as compared with the case where a single layer of CFRP plate having the same elongation rigidity of the CFRP plate and the aluminum alloy plate is bonded to the steel plate. However, even when the number N is two, if the peeling of the CFRP plate is prevented by the applied stress or the bonding time between the CFRP plate and the AL plate, it can be used to reduce the thermal stress generated in the steel plate.

(Summary)
In this test example, the thermal stress generated in the steel plate due to temperature changes and the thermal stress generated in the bonding interface between the reinforcing material and the steel plate are reduced for the steel plate with the CFRP plate bonded symmetrically to the upper and lower surfaces (comparative example). We propose a method in which an aluminum alloy plate with a linear expansion coefficient approximately twice that of steel is bonded to a steel plate together with a CFRP plate, and a temperature change test and numerical analysis of a specimen in which the CFRP plate and the aluminum alloy plate are bonded to the steel plate The effect of reducing the thermal stress of the steel plate by the developed method and the thermal stress generated at the bonding interface between the reinforcing material and the steel plate was clarified. The main conclusions are as follows.

  1) An aluminum alloy plate was bonded together with a CFRP plate to develop a reinforcing method using a steel plate and a CFRP plate that does not generate thermal stress at the bonding interface between the reinforcing material (aluminum alloy plate + CFRP plate) and the steel plate. The elongation rigidity of the aluminum alloy plate necessary for setting the thermal stress generated in the steel plate to 0 at the center of the bonding of the CFRP plate can be calculated from the equation (2) (or (2-1)).

  2) A temperature change test is performed on a steel plate in which a CFRP plate and an aluminum alloy plate designed to satisfy the formula (2) (or (2-1)) are bonded, and a slight thermal stress is generated in the steel plate at the bonded end. However, it was shown to be 0 in other ranges. Furthermore, it was clarified that the thermal stress generated in the steel plate at the bonded end can be reduced by increasing the number of laminated reinforcing plates under the condition that the elongation stiffness of the entire reinforcing plate is equal. The sign of the thermal stress of the steel plate generated at the bonded end depends on the difference in linear expansion coefficient between the steel plate and the reinforcing plate on the side close to the steel plate.

  That is, although the thermal stress generated in the steel material by two layers of the CFRP plate and the aluminum alloy plate is small, when the formula (2-1) is satisfied, the number of laminated layers is 3 or more (that is, CFRP plate + aluminum alloy). Plate + CFRP plate, or aluminum alloy plate + CFRP plate + aluminum alloy plate or more) The steel plate is made of a reinforcing material having the same elongation rigidity of the CFRP plate and the aluminum alloy plate as the thermal stress generated in the steel plate and the shear stress generated in each adhesive. It can be reduced as compared with the case of bonding.

  3) According to the reinforcing method of the present invention, it was shown that the absolute value of the shear stress generated in the adhesive immediately above the steel plate is smaller than when only the CFRP plate is bonded. Furthermore, it was clarified that the absolute value of the shear stress generated in the adhesive immediately above the steel plate can be reduced by increasing the number of laminated reinforcing plates under the condition that the elongation stiffness of the entire reinforcing plate is equal.

  As has become apparent from the above test examples, according to the steel structure reinforcing method and the steel structure reinforcing laminated material of the present invention, the reinforcing material bonded to the steel structure surface by temperature change. It is possible to reduce the thermal stress generated at the bonding interface between the steel and the steel material surface and the thermal stress generated in the steel material, thereby obtaining a sufficient reinforcing effect.

1 Reinforcing fiber-containing material (fiber sheet, fiber-reinforced resin plate)
10 Alloy plate 100 Steel structure reinforcement (reinforced laminate)
110 Adhesive 200 Steel structure (steel material, steel plate)

Claims (23)

In a method for reinforcing a steel structure in which a reinforcing material is bonded to the surface of the steel material constituting the steel structure with an adhesive,
The reinforcing material is composed of a reinforcing fiber-containing material having a smaller linear expansion coefficient than the steel material constituting the steel structure, and an alloy plate having a larger linear expansion coefficient than the steel material,
At least one layer of the reinforcing fiber-containing material and the alloy plate are alternately bonded and laminated on the surface of the steel material with an adhesive, and the steel material, and the reinforcing material and the steel material by temperature change of the steel material. A method for reinforcing a steel structure, characterized by reducing a thermal stress generated at an adhesive interface of the steel structure. In a method for reinforcing a steel structure in which a reinforcing material is bonded to the surface of the steel material constituting the steel structure with an adhesive,
The reinforcing material is composed of a reinforcing fiber-containing material having a smaller linear expansion coefficient than that of the steel material constituting the steel structure and an alloy plate having a larger linear expansion coefficient than that of the steel material. Is composed of
The reinforcing material is bonded to the surface of the steel material with an adhesive, and thermal stress generated at the bonding interface between the steel material and the reinforcing material and the steel material due to a temperature change of the steel material is reduced. A method of reinforcing steel structures.   The method for reinforcing a steel structure according to claim 1 or 2, wherein the reinforcing material has at least three layers of the reinforcing fiber-containing material, the alloy plate, and the reinforcing fiber-containing material.   The method for reinforcing a steel structure according to any one of claims 1 to 3, wherein the reinforcing fiber-containing material is bonded to the surface of the steel material.   The method of reinforcing a steel structure according to claim 1 or 2, wherein the reinforcing material includes at least three layers of the alloy plate, the reinforcing fiber-containing material, and the alloy plate.   6. The method for reinforcing a steel structure according to claim 1, wherein the alloy plate is bonded to the surface of the steel material.   The linear expansion coefficient (αs) of the steel material is 10 (μ / ° C.) ≦ αs ≦ 12 (μ / ° C.), and the linear expansion coefficient (αf) of the reinforcing fiber-containing material bonded to the steel material is − 15 (μ / ° C.) ≦ αf <αs, and the linear expansion coefficient (αa) of the alloy plate is αs <αa ≦ 30 (μ / ° C.). The method for reinforcing a steel structure according to the section. 8. The thickness of each layer of the reinforcing fiber-containing material (FRP plate) and the alloy plate bonded to the steel material is calculated by the following formula, according to claim 1. Steel structure reinforcement method.

  The said reinforcing fiber containing material is produced with the fiber sheet which mutually fixed the continuous reinforcing fiber arranged in one direction with the wire fixing material, The one of Claims 1-8 characterized by the above-mentioned. A method of reinforcing steel structures.   The reinforcing fiber-containing material is a fiber sheet in which reinforcing fibers are impregnated with a matrix resin, a plurality of cured continuous fiber-reinforced plastic wire materials are arranged in a slender shape in the longitudinal direction, and the wire materials are fixed to each other by a wire fixing material. The method for reinforcing a steel structure according to claim 1, wherein the steel structure is manufactured by:   The reinforcing fiber-containing material is a fiber-reinforced resin plate in which a continuous reinforcing fiber sheet aligned in one direction is impregnated with a resin and the resin is cured. The method for reinforcing a steel structure according to the item.   The method for reinforcing a steel structure according to any one of claims 1 to 11, wherein the alloy plate is an aluminum alloy, a stainless alloy, or a magnesium alloy. The reinforcing fibers of the reinforcing fiber-containing material are inorganic fibers such as carbon fibers, glass fibers and basalt fibers, or organic fibers such as aramid, PBO (polyparaphenylene benzbisoxazole), polyamide, polyarylate, and polyester. Or mixed with multiple types and used in hybrid,
The matrix resin impregnated in the reinforcing fiber-containing material and the adhesive are heat-curable epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, phenol resin, etc. The method for reinforcing a steel structure according to any one of claims 1 to 12, which is a curable resin or a thermoplastic resin such as nylon or vinylon. A steel structure reinforcing laminate for reinforcing a steel structure by bonding with an adhesive to the surface of the steel material constituting the steel structure,
The reinforcing fiber-containing material having a smaller linear expansion coefficient than that of the steel material constituting the steel structure and the alloy plate having a larger linear expansion coefficient than that of the steel material are alternately laminated at least one layer with an adhesive. A laminated material for reinforcing steel structures.   The laminated material for reinforcing a steel structure according to claim 14, comprising at least three layers of the reinforcing fiber-containing material, the alloy plate, and the reinforcing fiber-containing material.   The steel structure reinforcing laminate according to claim 14, comprising at least three layers of the alloy plate, the reinforcing fiber-containing material, and the alloy plate.   The linear expansion coefficient (αs) of the steel material is 10 (μ / ° C.) ≦ αs ≦ 12 (μ / ° C.), and the linear expansion coefficient (αf) of the reinforcing fiber-containing material bonded to the steel material is − 15 (μ / ° C.) ≦ αf <αs, and the linear expansion coefficient (αa) of the alloy plate is αs <αa ≦ 30 (μ / ° C.). The laminated material for steel structure reinforcement as described in the item of. The thickness of each layer of the said reinforcing fiber containing material (FRP board) and the said alloy board is calculated by the following formula, The steel structure reinforcement for any one of Claims 14-17 characterized by the above-mentioned. Laminated material.

  The said reinforcement fiber containing material is produced with the fiber sheet which mutually fixed the continuous reinforcement fiber arranged in one direction with the wire fixing material, The one of Claims 14-18 characterized by the above-mentioned. Laminate for reinforcing steel structures.   The reinforcing fiber-containing material is a fiber sheet in which reinforcing fibers are impregnated with a matrix resin, a plurality of cured continuous fiber-reinforced plastic wire materials are arranged in a slender shape in the longitudinal direction, and the wire materials are fixed to each other by a wire fixing material. The laminated material for reinforcing steel structures according to any one of claims 14 to 19, wherein the laminated material is for reinforcing steel structures.   21. The fiber-reinforced resin plate according to claim 14, wherein the reinforcing fiber-containing material is a fiber-reinforced resin plate in which a continuous reinforcing fiber sheet aligned in one direction is impregnated with a resin and the resin is cured. A laminated material for reinforcing steel structures according to item.   The steel alloy reinforcing laminated material according to any one of claims 14 to 21, wherein the alloy plate is an aluminum alloy, a stainless alloy, or a magnesium alloy. The reinforcing fibers of the reinforcing fiber-containing material are inorganic fibers such as carbon fibers, glass fibers and basalt fibers, or organic fibers such as aramid, PBO (polyparaphenylene benzbisoxazole), polyamide, polyarylate, and polyester. Or mixed with multiple types and used in hybrid,
The matrix resin impregnated in the reinforcing fiber-containing material and the adhesive are heat-curable epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, phenol resin, etc. The laminated material for reinforcing a steel structure according to any one of claims 14 to 22, which is a curable resin or a thermoplastic resin such as nylon or vinylon.

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