JPH08177818A - Bolt connecting splice plate - Google Patents

Abstract

PURPOSE: To improve connection resistance by applying a steel mesh having strength higher than that of a connected mother steel plate to a plate surface, and thereby attaining a high sliding coefficient on a frictional connection surface of a high power bolt. CONSTITUTION: The stronger steel wire is, the higher the frictional resistance is. The steel wire necessarily has hardness higher than that of a lowermost connected steel plate 1 and a splice plate 2. The hardness ranges between twice of the steel plate 1 and eight times of the steel plate 1, only by improving friction as biting anchor effect of the steal wire due to bolt fastening. A diameter of the steel wire may be not less than 0.2mm in order to secure surface roughness through blasting treatment. A sliding coefficient is dependent on roughness and hardness of a frictional connection surface. The frictional coefficient is saturated or lowered in the case of excessive wire diameter and roughness, so that the wire diameter is not more than 1.0mm. The roughness of the frictional connection surface is influenced by mesh, which is preferably not more than 100 mesh. Connection strength of the steel mesh must be a value which is only enough not to escape. It is thus possible to easily obtain a high and stable sliding coefficient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a splice plate at the time of bolt joining, and can be used for a friction joining portion of a steel structure in a building or a bridge. By using the splice plate according to the present invention, a high slip coefficient can be stably obtained, and as a result, high slip resistance can be exhibited and the safety of the steel structure can be further enhanced.

[0002]

2. Description of the Related Art In high strength bolt friction welding, according to the design and construction guidelines of the Japan Institute of Architecture, the friction surface that is important in terms of joint strength is a good red rust surface with black skin removed and a slip coefficient of 0.
It is said that it is necessary to perform a treatment exceeding 45 and to confirm the slip coefficient by a slip proof test. Generally, it is known that the slip coefficient exceeds 0.45 in a good red rust state, and the slip proof test is often omitted.

Although a slip coefficient of about 0.6 may be obtained in the red rust state, the rust formation state varies depending on environmental factors, steel material composition, etc., so that there are large variations, and the slip coefficient is designed to be 0.45. It seems that It is clear that the slip coefficient of the friction-bonded surface is preferably as high as possible in terms of the bonding strength. In JP-A-51-52628, the bonded surface is made uneven before construction, and in JP-A-1-206104, the bonded surface is corrosion-resistant. High frictional resistance is generated by spraying metal. However, these methods require some processing or treatment on the friction-bonded surface, and there are problems in terms of cost and stable supply in wide industrial use, and they are not always widespread.

[0004]

DISCLOSURE OF THE INVENTION The present invention is a very simple method in which a steel wire mesh having a strength higher than that of a mother steel plate to be welded is attached to a friction welded surface of a splice plate surface as described in the claims. The present invention provides a splice plate for joining bolts that exhibits a high slip coefficient.

[0005]

The gist of the present invention is a splice plate for bolt joining, characterized in that a steel wire mesh having a strength higher than that of a mother steel plate to be joined is attached to the plate surface.

[0006]

In order to increase the high-strength bolt friction welding efficiency, the method of increasing the surface roughness of the friction welding surface by shot or grid blasting is considered to be the simplest method. However, the surface roughness, that is, the difference in height of the surface irregularities due to blasting, is at most 150 μm, depending on the type of steel and shot grains.
However, there is a limit to the increase in the slip coefficient.

According to the research conducted by the present inventors, the larger the surface roughness is, and if the surface roughness is the same, the higher the hardness (surface hardness) of the friction-bonded surface on the splice plate side is, the higher the slip coefficient becomes. It became clear that it would be higher. Based on these findings, the present invention has been accomplished as a method for easily securing both the surface roughness and the surface hardness of the friction-bonded surface. That is, by simply sticking a mesh of a steel wire having an appropriate wire diameter and strength to the friction-bonding surface on the splice plate side, it is a very simple method of substituting the surface roughness of the steel sheet and ensuring the surface hardness. High friction (high slip coefficient) was achieved by the method.

The present invention will be described below. As described above, the higher the strength of the steel wire is, the more preferable it is for high friction, and it is necessary that the steel wire is harder than the mother steel plate (steel plate to be joined) and the splice plate. This is because the steel wire bites into both of them by fastening the bolts to increase friction as an anchor effect. However, if the strength is too high, not only the effect of high friction is saturated, but also the cost of the steel wire itself becomes high. According to the experiments conducted by the present inventors, the strength is preferably twice or more that of the mother steel plate, and the upper limit is 8 times or less.

The wire diameter of the steel wire has an effect on the surface roughness, and in order to ensure the surface roughness equal to or higher than that which can be easily obtained by blasting or the like in order to clarify the characteristics of the present invention, 0 A wire diameter of 0.2 mm or more is preferable. However, since the slip coefficient depends on the roughness and hardness of the friction-bonded surface, it is possible to obtain a high slip coefficient even if the wire diameter is less than 0.2 mm depending on the hardness, that is, the strength of the steel wire. Therefore, the wire diameter is not particularly limited. However, if the wire diameter, that is, the roughness is too large, the slip coefficient may be saturated or, conversely, decreased, so a wire diameter of 1.0 mm or less is preferable.

The roughness of the friction-bonded surface is affected not only by the wire diameter of the steel wire but also by the mesh. In the present invention, it is preferably 100 mesh or less. When it exceeds 100 meshes, it depends on the diameter of the steel wire, but when it is sandwiched between the steel plates, the substantial roughness becomes small, and the anchor effect is difficult to obtain. Further, it is not preferable to make the mesh finer than necessary because the cost of manufacturing the steel wire mesh increases.

Although the cross-sectional shape of the steel wire is not particularly limited, it is possible to take an arbitrary shape by means of a drawing die, which does not prevent high friction. The reason why the steel wire mesh is attached is to prevent the mesh from being easily dropped during handling by attaching the steel wire mesh, and the adhesive strength does not influence the slip resistance. Therefore, it is sufficient that the adhesive strength is sufficient to prevent falling off, and not only sticking with a commercially available adhesive, but also any method such as diffusion bonding may be used.

[0012]

EXAMPLE In order to show the usefulness of the present invention, a slip coefficient was measured using a test body as shown in FIG. Base material 1,
The splice plate 2 was made of SM490A steel, and the bolt 3 was made of F15T. Table 1 shows the details of the steel wire mesh attached between the base material to be joined and the splice plate and the measurement results of the slip coefficient.

When the splice plate according to the present invention was used (Examples), all exhibited high slip coefficients of 0.9 or more, while the comparative example, that is, the conventional red rust with no steel wire mesh attached. Alternatively, even if the roughness is simply increased by blasting, the slip coefficient is about 0.7 at the maximum, which clearly shows the usefulness of the present invention.

[0014]

[Table 1]

[0015]

According to the present invention, a stable and high slip coefficient (0.9 or more) can be easily obtained. As a result, it can be provided as a structural member that enhances the reliability of the high-strength bolt friction joint in the fields of construction and bridges, and its industrial value is great.

[Brief description of drawings]

FIG. 1 shows a test body for measuring a slip coefficient at the time of high-strength bolt friction welding.

[Explanation of symbols]

 1 Mother plate to be joined 2 Splice plate 3 Bolt 4 Jig plate

Claims (1)

[Claims] 1. A splice plate for joining bolts, characterized in that a steel wire mesh having a strength higher than that of a mother steel plate to be joined is attached to the surface of the plate.