JP2002129657A - Joint structure of frp structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide joint structure of an FRP structure in which the mutual joint parts of FRP thick-walled members have sufficient joint strength. SOLUTION: In this joint structure 11 of an FRP structure 10 for jointing thick-walled members 1, 2 formed of FRP using a bolt 4 and a nut 5 to form the FRP structure 10, a thin plate member 13 having sharp protrusions 14 biting into FRP joint faces 12 of a joint part 11, on both faces is interposed between the FRP joint faces 12 to joint by the bolt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for an FRP structure, and more particularly to a joint structure for joining thick members formed of FRP using bolts and nuts.

[0002]

2. Description of the Related Art Fiber reinforced plastics (Fiber Re
An FRP structure formed by inforced plastics (hereinafter, referred to as FRP) is applied to general industries (for example, the body of an automobile) or an aircraft industry. Small diameter rivets (for example, φ4.8) are frequently used for industrial applications, and small diameter rivets of about φ6.4 are also frequently used for aircraft industry.

[0003] Since FRP has characteristics of being lightweight and not corroding (ie, maintenance-free), it has recently been used in the field of civil engineering structures such as bridges.
Attempts to apply FRP members have begun. Here, when the FRP member is applied to a large civil engineering structure such as a bridge, the thickness of the FRP member used for the structure increases, so that the small-diameter rivet used for general industrial use (or aircraft industrial use) is used. Instead, the use of large diameter bolts (e.g., M20-M24 bolts as used in steel bridges) is preferred.

Generally, when a thick member is joined by using a large-diameter bolt, a simple structure is employed in which the thick member is fastened from both ends with bolts and nuts via washers.
In this case, as the joining method, there are two types of bearing joining and friction joining.

[0005] Since the bearing joining is a joining method in which a tensile stress or a compressive stress is applied to the inner peripheral surface of the bolt hole formed in the thick member and the axis of the bolt, the inner peripheral surface of the bolt hole is connected to the bolt. The shaft must be in close contact. For this reason, when manufacturing a thick member, it is necessary to process the bolt hole with high accuracy, and the manufacturing is not easy.

[0006] On the other hand, friction welding is a joining method in which a tensile force or a compressive stress is resisted by the frictional force between the joining surfaces of the thick-walled members. There is no need to closely contact the peripheral surface and the bolt shaft. For example, when joining thick steel members, the joining is performed by the contact pressure between the steel joining surfaces and the contact between the thick members (frictional force) by tightening the bolts and nuts. Therefore, in the friction joining, since it is not necessary to form a bolt hole with high precision, the production of a thick member is easier and the production cost is lower than in the case of the bearing joining.

[0007] For this reason, even in the case of thick members made of FRP, friction joining using bolts having a large diameter has been attempted.

[0008]

However, the FRP
When thick members made of steel are friction-joined to each other, the tightening force between the bolt and the nut may decrease during long-term operation, that is, the surface pressure may decrease, depending on the initial bolt tightening force. At this time, if there is a bite between the thick members between the joining surfaces, the joining strength can be secured,
Since the hardness and elastic modulus of the FRP thick member and the bolt (or nut) are greatly different from each other, there is little biting between the FRP thick members between the joint surfaces, and it is expected that the friction force between the joint surfaces is almost expected. Can not. That is, in the case where the FRP thick members are friction-joined to each other, if the surface pressure due to the tightening between the bolt and the nut decreases, the joining strength cannot be secured.

An object of the present invention, which has been made in view of the above circumstances, is to provide a joint structure of an FRP structure in which a joint between FRP thick members has a sufficient joint strength.

[0010]

In order to achieve the above object, a joint structure of an FRP structure according to the present invention is formed by joining thick members formed of FRP using bolts and nuts to form an FRP structure. In the joint structure of the FRP structure, bolt joining is performed by interposing a thin plate member having sharp projections on both sides between the FRP joint surfaces of the joint portion.

According to the above construction, the joint portion is integrally and mechanically strongly joined by bolting the FRP joint surface of the joint portion via the thin plate member.

Further, the thickness of the thin plate member is 0.5-1.
Preferably, the height of the protrusion is 5 mm or less.

Further, the thin plate member may be formed of stainless steel or ceramics.

Further, the projection may be formed by a needle-shaped notch or a conical piece.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an FRP structure in which beams and breaths formed by FRP are joined by bolts. FIG. 2 is a schematic view of the joint structure of the FRP structure according to the present invention. still,
FIG. 1B is a view in the direction of arrow A in FIG.

As shown in FIGS. 1 (a), 1 (b) and 2, the joint structure 11 of the FRP structure 10 according to the present invention comprises:
A beam 1 and a breath 2 (hereinafter, referred to as an FRP thick member) formed of FRP, and a bracket 3 also formed of FRP.
(Hereinafter referred to as FRP thick member) and bolted with bolts and nuts 4 and 5 to form a bridge (FRP structure)
10 is formed, and between the joining surfaces 12 (between the FRP joining surfaces) of the FRP thick members (the breath 2 and the bracket 3 in FIG. 2) of the joint portion (bolt joining portion) 11 in the bridge 10
It is bolt-joined with a thin plate member 13 having sharp projections 14 on both sides of the joint surface 12 interposed therebetween.

Here, the thin plate member 13 is provided so that at least the entire joining surface 12 is covered.
Placed between. That is, it is preferable that the thin plate member 13 has the same shape as the joining surface 12 or that the thin plate member 13 has a shape larger than the joining surface 12.

Examples of the plastic forming the FRP thick member include vinyl ester and thermosetting resin.
For example, unsaturated polyester resin as a thermosetting resin,
Epoxy resins, phenolic resins and the like can be mentioned. Further, the reinforcing fiber of the FRP thick member may be either glass fiber or carbon fiber.

The material of the thin plate member 13 is not particularly limited as long as it is higher in hardness than the plastic forming the FRP thick member, and examples thereof include stainless steel and ceramics.

The thinner the thin plate member 13 is, the better it is. For example, if the thickness of the joint portion 11 of the FRP thick member is 10
mm, the thickness of the thin plate member 13 is about 1/10 of that,
Preferably, it is 0.5 to 1.0 mm. In this case, the height of the projection 14 of the thin plate member 13 is not particularly limited as long as it is a height that can bite into the FRP thick member and is within the plate thickness of the FRP thick member. Is about 1 mm or less.

The shape of the projection 14 of the thin plate member 13 is as follows.
As shown in FIG. 3A, the needle-shaped notch pieces 31a (31b) formed by bending, such as shearing and bending, are on the back surface (FIG.
(A), a needle-shaped notch bent on the lower surface), FIG.
As shown in (b), a conical piece 32a (32b is a conical piece formed on the back surface (the bottom surface in FIG. 3B)) formed in a convex shape by press working or the like is exemplified. FIG.
As a modified example of the needle-shaped notches 31a and 31b shown in FIG. 4A, as shown in FIG. 4A, a cut 33 is formed radially by shearing, and this cut is alternately formed on the front, back, front,. To form an annular needle-shaped notch (not shown). Further, the conical pieces 32a and 32b in FIG. 3B have a polygonal pyramid shape (a quadrangular pyramid in FIG. 3B).
As shown in (b), conical conical pieces 34a and 34b may be used. In FIG. 3A, the bending directions of the needle-shaped notches 31a and 31b are all the same, but the bending directions may be random.

The interval between the projections 14 is determined by the difference in hardness between the plastic forming the FRP thick member and the thin plate member 13 (projection 14), that is, the degree of biting of the projection 14 into each joint surface 12 due to the hardness difference, or the projection 14. Is appropriately selected depending on the height of the object.

Next, the operation of the present invention will be described.

Even if the joints between the FRP thick members are directly fastened and joined together with the bolts 4 and the nuts 5 via washers, little biting between the FRP thick members occurs between the joint surfaces 12. Therefore, the joint portion is joined only by the tightening force between the bolt and the nut, that is, the surface pressure. In the case of joining using only surface pressure by tightening between a bolt and a nut, the joining strength of the entire joint portion is insufficient, so that joining may be performed in combination with an adhesive. However, in this case, it is necessary to manage the adhesive (various conditions such as temperature and humidity at the time of joining and maintenance of the adhesive layer after joining). Further, when tensile stress (or compressive stress) is continuously applied to the bonding surface 12 after bonding and finally leads to fracture, cracks are generated in the adhesive layer by the stress at a stage earlier than at the time of fracture. Therefore, immediately before breaking, the adhesive layer does not contribute to joining at all.

On the other hand, the thin plate member 13 having the projections 14 on both surfaces is interposed between the joint surfaces 12 of the joint portions 11 of the FRP thick members, and bolted together.
The protrusions 14 on each surface of the thin plate member 13 bite into each joint surface 12 of the FRP thick member and reach the vicinity of the fiber reinforced portion of the FRP thick member. That is, through the thin plate member 13,
The joint portion 11 is integrally and mechanically firmly joined.

When the joints 11 are integrally joined, a frictional force against tensile stress (or compressive stress) is generated between the joint surfaces 12, and the joints 11 are joined by the surface pressure and the frictional force. As a result, the joint strength of the entire joint is improved as compared with the joint of the conventional FRP structure. Also, joint 1
1 is mechanically formed by the projections 14 of the thin plate member 13. For this reason, when tensile stress (or compressive stress) is continuously applied to the bonding surface 12 after bonding and finally breaks, the time when a crack is generated in the projection 14 due to the stress, that is, the time of breaking. The projection 14 contributes to the joining until just before the fracture.

If the projections 14 have such a height as to reach the fiber reinforced portion of the FRP thick member, the projections 14 may damage the reinforcing fibers and cause a reduction in the strength of the FRP itself. There is. In this case, the spacing between the protrusions 14 may be changed as appropriate according to the type of the reinforcing fibers of the FRP thick member or the weaving (arrangement) thereof so that the protrusions 14 bite into the mesh portion of the reinforcing fibers. .

The surface pressure caused by the tightening between the bolt 4 and the nut 5 is saturated by a certain amount of tightening (that is, the surface pressure becomes constant after a certain amount of tightening). However, the biting between the FRP thick members on the joint surface 12 is caused by the material of the FRP thick member and the thin plate member 13 and the protrusions 14.
It can be freely adjusted by adjusting the shape and height of the projections, the biting condition of the projections 14 with respect to the respective joint surfaces 12, and the like. Therefore, by adjusting the bite between the FRP thick members on the joint surface 12, the joint strength of the entire joint portion 11 of the FRP structure 10 can be freely adjusted.

As described above, according to the joint structure of the FRP structure 10 according to the present invention, the thin plate member 13 having the projections 14 on both surfaces is interposed between the joint surfaces 12 of the joint portions 11 of the FRP thick members. By joining, the joint portion 11 can be integrally and mechanically strongly joined, and the friction joint can be performed at the joint portion 11 of the FRP structure 10 as well as the high strength bolt joint of the steel structure. Thus, it is possible to construct a large-scale structure using the FRP thick member.

Since the FRP thick member is lighter in weight than a conventional thick member made of steel (or concrete), even a member group including several members is light in weight. For this reason, the member group assembled in the factory in advance,
It can be transported and transported to the work site by a trailer, crane, etc., and workability at the work site is improved. Also, FR
A large-scale structure using a P-thick member can significantly reduce the weight (for example, 以下 or less) as compared with a conventional steel (or concrete) structure. The size (or number) of the substructures supporting the structures can be reduced (or reduced) as compared with the related art.
As a result, it is possible to reduce the construction period and the construction cost.

As described above, in the embodiment of the present invention, F
Although the description has been given using a bridge as an example of the RP structure, the FRP structure having the joint structure according to the present invention is not limited to the bridge, and various other structures are assumed.・ Balconies and roof fences of buildings, etc.
It is needless to say that the present invention can be applied to various towers and stands for radio waves, antennas, lighting, and the like, towers, marine structures, various structures in the general industry or the aircraft industry.

[0033]

In summary, according to the present invention, the FRP thick-walled member is formed by interposing a thin plate member having projections on both surfaces between joint surfaces of joints between thick members formed of FRP. An excellent effect that a sufficient joint strength can be given to the joint portion between the members is exhibited.

[Brief description of the drawings]

FIG. 1 is a schematic view of an FRP structure formed by bolting beams or breaths formed of FRP.

FIG. 2 is a schematic view of a joint structure of an FRP structure according to the present invention.

FIG. 3 is a perspective view showing a shape of a projection of a thin plate member.

FIG. 4 is a perspective view showing a shape of a projection of a thin plate member.

[Explanation of symbols]

 Reference Signs List 1 beam (thick member) 2 breath (thick member) 4 bolt 5 nut 10 bridge (FRP structure) 11 joint structure 12 joint surface (FRP joint surface) 13 thin plate member 14 protrusion 31a, 31b needle-like cutout 32a, 32b cone

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) // E01D 19/00 E01D 19/00 (72) Inventor Tsutomu Suzuki Harima Ishikawajima Harima 1-19-10 Mori, Koto-ku, Tokyo Heavy Industries, Ltd. Koto Office (72) Inventor Nobuhiko Kitayama 1-19-10 Mori, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Koto Office F-term (reference) 2D059 AA05 GG01 GG55 2E125 AA13 AA33 AA35 AB01 AB05 AC21 AG03 AG04 AG12 BB02 BB27 BB36 BC01 BC03 BC06 BD01 BE08 CA05 CA14 CA78 EA14 EA17 EB11 2E163 FA12 FE03 3J001 FA02 GA06 GB01 HA02 JA10 KB04

Claims (4)

[Claims] An FRP for forming an FRP structure by joining thick members formed of FRP using bolts and nuts.
A joint structure for an FRP structure, characterized in that in a joint structure of an RP structure, a thin plate member having sharp projections on both surfaces interposed between the FRP joint surfaces of a joint portion is bolted to each other. 2. The thin plate member has a thickness of 0.5 to 1.5 m.
2. The joint structure for an FRP structure according to claim 1, wherein the height of the protrusion is 1 mm or less. 3. The joint structure for an FRP structure according to claim 1, wherein said thin plate member is formed of stainless steel or ceramics. 4. The joint structure for an FRP structure according to claim 1, wherein the projection is formed of a needle-shaped notch or a conical piece.