JPH0510024Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hood made of fiber-reinforced plastic pipe that is installed around and protects structures such as bridge piers constructed underwater in sea areas.

[Conventional technology] Traditionally, hoods installed around structures such as bridge piers built underwater in sea areas to protect them can be roughly divided into elastic deformation type and plastic deformation type (or crushing type). There are two types. Elastically deformable hoods have a simple structure, such as old tires tied tightly together with chains or wires, and suspended around bridge piers. In addition, the latter type of plastic deformation type shock absorbers are used when absorbing large amounts of energy, and are equipped with steel shock absorbers with multiple compartments arranged in a honeycomb shape, or the ones mentioned above. In some cases, the compartment is filled with an energy absorbing material such as a foam material, and a pneumatic fender made of plastic or rubber is attached to the outer periphery of the cushioning material.

[Problem to be solved by the invention] Simple structures such as the above-mentioned elastically deformable old tires tied tightly with chains or wires and suspended around bridge piers do not have sufficient protection. be. In addition, plastic deformation type steel hoods with multiple compartments arranged in a honeycomb configuration have corrosion prevention problems because the buffer material repeatedly appears and disappears from the water surface depending on the rise and fall of the water surface. There are problems such as fatigue cracks occurring in the cushioning material, which is made up of multiple compartments in a honeycomb structure, and deterioration of the filled foam material, etc. due to variable loads due to buoyancy when emerging from the water surface. .

The present invention has been made to solve the above-mentioned problems, and aims to provide a hood made of fiber-reinforced plastic pipe that can quickly absorb the energy of foreign objects colliding with bridge piers, etc.

[Means for solving the problem] The fiber-reinforced plastic pipe hood according to the present invention is made by bundling multiple composite fiber-reinforced plastic pipes in which a plurality of fiber-reinforced plastic pipes with different strength performance are concentrically stacked. It is a structure.

[Function] This invention creates a structure in which multiple fiber-reinforced plastic pipes with different strength performance are bundled together, in which multiple fiber-reinforced plastic pipes with different strength performance are stacked concentrically. By shifting, the fracture distance is increased, and as much energy as possible can be absorbed under a predetermined crushing load and within a predetermined crushing distance.

[Example] Hereinafter, an example of the fiber-reinforced plastic pipe buffer hood of the present invention will be described with reference to FIGS. 1 to 4. Figure 1 shows a cross-sectional view of a composite FRP pipe constituting a hood made of fiber-reinforced plastic pipe (hereinafter referred to as FRP pipe) of the present invention.
In pipes, fibers made of glass fiber, etc., have different stiffness, content, layer orientation, etc., resulting in different strength performance.
FRP pipes 1a, 1b, and 1c are concentrically inscribed or circumscribed and superimposed on each other. A hood is a structure in which a plurality of such composite FRP pipes 1 are bundled around a pier 2 as shown in FIG. 2.

First, the relationship between the load and the amount of deformation of a single FRP pipe (hereinafter referred to as the P~δ relationship) is a/Pcr・δcr when a crushing load w is applied as shown in Figure 4.
The energy absorption efficiency expressed as (Pcr: critical crushing load, δcr: critical deflection distance) is only 1/2 (shaded area in the figure).

In order to improve the performance of such a single FRP pipe as much as possible, it is necessary to keep the P~δ relationship constant, and simply using a single FRP pipe, which is a brittle material, will not solve this problem. I can't solve it.

FRP pipes 1a, 1b as shown in Fig. 1,
By making the composite FRP pipe 1 made of 1c, its performance can be improved. That is, when a crushing load is applied to such a composite FRP pipe, a shift occurs in the crushing timing of FRP pipes 1a, 1b, and 1c, and a P~δ relationship as shown in Fig. 3 is obtained, and the energy Absorption efficiency increases. As shown in FIG. 2, by forming a structure in which a plurality of the composite FRP pipes 1 are bundled around the pier, a hood with extremely high energy absorption efficiency can be obtained.

[Effects of the invention] As described above, according to the fiber-reinforced plastic pipe hood of the present invention, there is no problem of corrosion or fatigue cracking caused by liquids such as seawater, and a hood that has high crushing energy absorption efficiency can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a composite FRP pipe according to an embodiment of the fiber-reinforced plastic pipe hood of the present invention, and Fig. 2 is a schematic cross-section showing an embodiment of the fiber-reinforced plastic pipe hood of the present invention. figure,
3 and 4 are graphs showing the relationship between the crushing load ρ and the crushing distance δ of a composite FRP pipe and an FRP pipe. 1...Composite FRP pipe, 1a, 1b, 1c...
...FRP pipe, 2...Pier.

Claims (1)

[Scope of utility model registration request] A shock absorber made of fiber-reinforced plastic pipes, characterized in that it is a structure in which a plurality of composite fiber-reinforced plastic pipes, in which a plurality of fiber-reinforced plastic pipes having different strength performance are concentrically stacked, are bundled.