JP3880565B2 - FRPM pipe joint structure - Google Patents

Description

  The present invention relates to a joining structure of an FRPM tube. Here, the FRPM pipe refers to a pipe formed from a pipe wall formed by integrally forming a resin mortar layer as an intermediate layer on the outer surface of the FRP inner layer, and further forming an FRP outer layer on the outer surface to form three layers. In the specification, it is hereinafter referred to as an FRPM pipe.

  As a pipe joining means for FRP pipes and FRPM pipes made of fiber reinforced plastic, as shown in FIG. 11, the FRPM pipes 1 and 1 are abutted, the abutted pipe end surfaces 2 and 2 are joined together, and a reinforcing resin is provided on the inner and outer circumferences. A joint pipe 5 (in the illustrated example, a curved pipe) in which an impregnated mat 4 is arranged and connected is known (Patent Document 1).

  By the way, since these joining pipes 5 are normally buried in the ground, earth pressure of backfilling soil is applied to the joining pipes 5, and the weight of passing vehicles is also added to the buried pipes under the road. For this reason, these joining pipes 5 are flatly deformed as shown in FIG. 2, and in the case of a straight pipe, there is no problem, but in the case of a bent pipe, as shown by a two-dot chain line in FIG. As shown by Q1, the joint end surfaces 2 and 2 are about to open, and on the inner side of the bend, the joint end surfaces 2 and 2 try to be deformed in the closing direction as shown by arrows Q2 and Q2. Therefore, in order to prevent deformation due to such a load, conventionally, the protective concrete 2 is placed around the bent pipe portion to protect it.

However, it is troublesome and time consuming to place the protective concrete 2 for each such joint in the pipeline.
Therefore, in order to improve the followability to deformation even if the external force as described above acts and to eliminate the damage of the pipe line, as shown in FIG. 13, the elastic body 3 is interposed between the joining end faces, and the periphery thereof is made of glass fiber and It has been proposed that the resin-impregnated mat 4 made of resin is laminated and integrated to improve follow-up deformability due to load (Patent Document 1).
JP 2000-291864 A

  By the way, generally, the thickness of the resin-impregnated mat 4 is easily increased to increase the strength of the joint portion. However, the thicker the layer is laminated, the more the elastic body 3 of the FRPM tube and the resin-impregnated mat 4 are. In spite of the elasticity of the resin to be formed, there has been a problem that the deformation of the joining tube 5 causes the resin impregnated mat 4 to be floated or peeled off on the curved or straight tube.

For this reason, there has been a problem that, as a safety measure, there is often a need for construction in which the outer periphery of the joint pipe is protected with protective concrete.
The present invention solves the above-mentioned problems and makes it possible to reduce the breakage due to deformation and the like and to easily connect even a joined pipe, particularly a bent pipe, which receives earth pressure and the weight of a passing vehicle. It was made as an issue.

In order to achieve this object, the present invention provides an FRPM pipe formed by integrally forming three layers by forming a resin mortar layer as an intermediate layer on the outer surface of the FRP inner layer and further forming an FRP outer layer on the outer surface thereof. At least one of the FRP inner layer and the FRP outer layer at the end portion is removed in a taper shape so that the layer thickness decreases toward the tube end direction, and the butted end portions are butt-joined to each other with an elastic body interposed therebetween. The resin-impregnated mat is placed and adhered to a uniform layer on the removed layer portion and the outer surface of the elastic body until the resin-impregnated mat has substantially the same thickness as the removed layer .

According to this invention, the adhesive layer formed by adhesion of the resin-impregnated mat is placed on at least one of the FRP inner layer and the FRP outer layer from which the taper is removed, and the adhesive layer has a layer thickness. Since there is no place where the strength changes suddenly, the adhesive layer is less likely to peel off even if the pipe is joined at the end of the pipe. It can be omitted.

Next, the structure of the deformed pipe according to the embodiment of the present invention will be described.
FIG. 1 is a cross-sectional view of a FRPM pipe joining structure according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a portion A in FIG.

  1 and 2, the FRPM tube 1 is integrally laminated with a resin mortar layer 10 on the outer surface of the FRP layer 12 and an FRP layer 11 on the outer surface, as shown in an enlarged view in FIG. Has been. The inner and outer FRP layers 11 and 12 are removed in a tapered shape so that the layer thickness gradually decreases toward the end of the pipe to be joined. In addition, as means for removing the taper, there are appropriate means such as cutting and polishing. However, it is preferable to use polishing for the convenience of processing of the glass fiber contained therein.

  Then, the tube end faces 13 and 13 having only the resin mortar layer 10 are inserted with an elastic body 14 having rubber-like elasticity such as an epoxy resin-based filler having a high followability to mechanical deformation, for example. The respective end surfaces 14 a and 14 a are bonded to the end surfaces 13 and 13 of the mortar layer 10.

  Then, the resin-impregnated mats 15 and 16 made of a resin-impregnated glass fiber mat or the like on the inner and outer FRP layers 11 and 12 removed in a tapered shape are uniform layers until the thickness becomes equal to or slightly thicker than the FRP layers 11 and 12. Is served.

  The inner and outer FRP layers 11 and 12 can make the maximum use of the necessary strength of the pipe by rationally orienting the fibers according to the magnitude and direction of the force acting on the pipe.

  Accordingly, the resin-impregnated mats 15 and 16 laminated and adhered to the taper portion are also attached with such an orientation that the fibers are evenly distributed in the vertical and horizontal directions so that the fiber orientation can maximize the required strength of the tube.

  In addition, although the case where the FRP layers 11 and 12 were removed over the entire circumference in the circumferential direction was shown as the above-described embodiment, as shown in FIGS. 11 (12) may be removed.

  That is, when both sides of the FRPM pipe 1 in FIG. 3 are bent toward the front side of the drawing, the outer FRP layer 11 is shown in FIG. 5 in the outer semicircular portion S1 which is the back side of the bent portion as shown in FIG. The inner FRP layer 12 is abutted as it is without being removed, and the inner semicircular portion S2 which is the ventral side of the bent portion in FIG. The outer FRP layer 11 is abutted as it is without being removed, and the laminated adhesive layers 15 and 16 are arranged and bonded to the respective removed portions and the abutting portions as shown in FIG.

  In this case, as shown in FIG. 3, when the earth pressure or the vehicle weight P is applied from the top of the pipe and the flat deformation as shown by a two-dot chain line in FIG. Since the outer FRP layer 11 and the inner FRP layer 12 are removed in a tapered shape, cracks and cracks are caused by the deformation of the elastic layer and the gradual change in the interface between the FRP layer 11 and the resin-impregnated mats 15 and 16. Peeling is less likely to occur.

Embodiments of the Invention Next, embodiments of the present invention will be described.
A 90 ° bent pipe having a diameter of 600 to 3000 mm was formed by axial joining of four short pipes as shown in FIG.

  Each of the short tubes 20, 21, 22, 23 has a shape in which one end short tube 20 has one end 20a perpendicular to the tube axis and the other end 20b having an inclination angle θ of 67.5 with respect to the tube axis. The inclined surface of ° and the two intermediate short tubes 21 and 22 are all inclined surfaces whose end surfaces 21a, 21b, 22a and 22b are 67.5 ° with respect to the tube axis X, and the other end short tube 14 is one end. By connecting the short pipes 23a having a right angle with respect to the tube axis X and the other end 23b having an inclined surface of 67.5 ° with respect to the tube axis X, the inclined surfaces 20b to 23a are connected as shown in the figure. A 90 ° bent tube was formed.

The FRP layers 11 and 12 on the end faces to which the short tubes 10, 11, 12, and 13 are joined are polished in a tapered shape as shown in FIG. 8, and the polished axial length is 100 to 200 mm. did.
In addition, the thickness of the resin mortar layer and the thickness of the FRP layer are 3 to 5 mm.
After the inner and outer FRP layers 11 and 12 of the short pipes 20 to 23 are polished in a tapered shape, an epoxy resin putty is formed on the pipe end face 13 to a thickness as shown in FIG. The tubes 20-23 were connected in series in the axial direction to form a 90 ° bent tube. Next, the resin-impregnated glass fiber mat 4 was placed and bonded to the tapered polished portions of the FRP layers 11 and 12 on the inner and outer surfaces of the tube so as to be 10% thicker than the FRP layer 1b.

  As a comparative example, the pipe end faces are directly abutted without being removed as shown in FIG. 9, and elastic bodies 14 having the same thickness as the FRP layers 11 and 12 are inserted on the outer surface, and the resin-impregnated mat 15 on the inner and outer surfaces. , 16 was affixed to the same type of bent tube as in the example and used for the test.

These bent pipes were placed horizontally, a load was applied to the pipe top, and the deflection rate at which the adhesive layer peeled was measured, and the results shown in the graph of FIG. 10 were obtained.
As is apparent from FIG. 10, in the comparative example, the joint was broken at a deflection rate of 4.2% when the load was 676 KN (69 tonf), but in the case of the example, the deflection rate was 794 KN (81 tonf) and the deflection rate was 5.2%. It was proved that it was not broken until it was excellent in strength.

  In addition, although the same test was implemented also about what was shown in FIG. 4, FIG. 5, it turned out that it became a result substantially the same as an Example, and an intensity | strength was superior to a comparative example.

It is a principal part fracture side view which shows the joining structure of the FRPM pipe | tube which is embodiment of this invention. It is the A section expanded sectional view of FIG. It is a principal part fracture side view which shows the curved pipe joining structure of the FRPM pipe | tube which is embodiment of this invention. FIG. 4 is a plan view of FIG. 3. It is a principal part fracture | rupture side view which shows the junction structure of the FRPM pipe | tube which is other Embodiment of this invention outside a bending part. It is a principal part fracture | rupture side view which shows the junction structure of the FRPM pipe | tube which is other Embodiment of this invention inside the bending part. It is a description top view of the 90 degrees curved pipe of the Example of this invention. It is sectional drawing which shows the structure of the junction part of the Example of this invention. It is sectional drawing which shows the structure of the junction part of a comparative example. It is a graph which shows a load test result. It is a sectional side view which shows the structure of the junction part of a prior art example. It is a longitudinal cross-sectional view which shows the structure of the junction part of a prior art example. It is a sectional side view which shows the structure of the junction part of another prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 FRPM pipe | tube 10 Mortar layer 11 Outer layer FRP layer 12 Interior FRP layer 13 Pipe end surface 14 Elastic body which has rubber-like elasticity 15 Laminated adhesive layer

Claims (3)

The resin mortar layer as an intermediate layer on the outer surface of the FRP inner layer, further said FRP inner layer and FRP outer layer of the pipe end portions that are joined together in FRPM tube formed by integrally formed with three layers to form a FRP outer layer on the outer surface thereof Are removed in a tapered shape so that the layer thickness decreases toward the tube end direction, and the butted tube ends are butt-joined to each other with an elastic body interposed therebetween, and the removed layer portion and An FRPM pipe joining structure in which a resin-impregnated mat is placed on and adhered to a uniform layer on the outer surface of the elastic body until the resin-impregnated mat becomes a layer having substantially the same thickness as the removed layer .   2. The FRPM pipe joining structure according to claim 1, wherein the pipe end surfaces of the FRPM pipes to be bonded together are inclined with respect to the pipe axis.   3. The FRPM pipe joining structure according to claim 2, wherein the FRPM pipe whose pipe end surface is inclined with respect to the pipe axis is a short pipe, and the short pipes are butt-joined in a series in the axial direction, and the bent pipe is formed by the joining. An FRPM tube joining structure formed to be formed.

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