JPH0475321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a corner bend buffering device for mitigating corner bends in a cable anchoring section, particularly in a cable-stayed bridge multi-cable anchoring section.

[Prior Art] Cable-stayed bridge cables play an important role in distributing the load of lifting girders of cable-stayed bridges with high-strength cables.

The anchoring structure for cable-stayed bridge cables takes into account the diameter and number of strands used, the socket type for fixing the cable ends, the pulling method, etc., but the elasticity of the girder and tower due to live load loading is important. Due to deformation, changes in cable sag (SAG), changes in the angle of the anchored portion of the cable due to vibration, etc., a bending moment is generated at the end of the cable anchored in the socket, reducing the durability of the cable.

[Problem that the invention seeks to solve]

As a countermeasure against this problem, the configuration of a corner bending buffer device Bf developed in the process leading to this invention is shown in FIGS. 3 and 4. In other words, this buffer device Bf is
This is a corner bending shock absorber in which the inner surface of the buffer body is filled only with synthetic resin 5, and the synthetic resin 5 is placed between the buffer body 3 fixed with the cover 1 and the cable 2 covered with the cable tube 2a. By injecting and curing the buffer, the buffer main body 3 and the cable 2 are integrated, and an effect of buffering the bending of the cable can be obtained.

As the material of the buffer body 3 , a weather-resistant elastomer such as chloroprene rubber or other elastic polymer material is used, and as the synthetic resin 5, a liquid resin such as a liquid epoxy resin is used.

However, the cable 2 is not necessarily located at the center of the buffer body 3 , but is often offset to one side, and the bias varies in size, so liquid resin is injected into the space and the buffer body is 3 and the cable pipe 2a are integrally fixed, liquid resin leaks from the gap between the cable pipe 2a and the buffer body 3 , so measures to prevent leakage of the injected resin are required when injecting the liquid resin. becomes. Typical methods include sealing with a sealant or the like, and methods such as prior injection of a fast-curing putty-like resin are also considered, but neither of these methods can be expected to provide sufficient functionality. Even more so, when the deviation is large, it is extremely difficult to prevent leakage.

Therefore, the present invention is capable of uniformly integrating the cable and the shock absorbing section body by always exhibiting an effective leak prevention effect regardless of the size of deviation from the center, and has an effective corner bending shock absorbing effect. An object of the present invention is to provide a corner bending buffer that can achieve the following.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides that an open cell foam made of easily deformable cellular rubber, cellular plastic foam, etc. is suitable as a material for preventing leakage of liquid resin. to clarify the matter,
In addition, the open cell foam acts as a leakage prevention material, and the open cell foam has a skin layer (film layer) formed on the inner side surface that is the contact surface with the injected resin side, that is, the synthetic resin. We have found this to be a necessary condition, especially in some cases.

That is, in this invention, liquid synthetic resin is injected into the space between the cable covered with the cable tube and the cylindrical body of the buffer main body, and the hardened synthetic resin layer seals the cable tube and the body. This is a corner bending shock absorber that integrates the cable with the body, and even if the cable is located eccentrically with respect to the body, liquid resin is prevented from leaking from the gap between the tip and the shock absorber body, and the installation operation is easy and quick. This device provides a corner bending shock absorber that can be split into two parts, consisting of a cylindrical body that surrounds a cable covered with a cable tube, and a lip that tapers from the body to the tip. a buffer body; an open-cell foam that is adhered to the inner circumferential surface of the lip-shaped portion and combined in a compressed truncated conical shape along the outer circumferential surface of the cable pipe; It consists of a synthetic resin layer that integrates a tube and a body, and the open cell foam is characterized by having a skin layer on the interface with the synthetic resin layer.

[Function] As mentioned above, the easily deformable open-cell foam is provided in the lip-like part, and this open-cell foam is compressed and combined into a truncated conical shape along the outer circumferential surface of the cable pipe, so that the cable Not only when the tube is not eccentric to the body, but even when it is eccentric, the compressed open cell foam and the skin layer formed on the interface moderately suppress the penetration of the liquid synthetic resin. It is possible to reliably deal with deviations from various centers.

The buffer main body and the cable can always be integrated with a uniform filled synthetic resin layer, and a shock absorber that exhibits a good corner bend buffering effect can be realized with suitable workability.

[Examples] Examples of the present invention will be described below with reference to the drawings.

In the figure, 1 is a cover, 2 is a cable pipe 2a
It is a cable coated with The buffer main body 3 is
It consists of a cylindrical body part 3a and a lip part 3b that tapers from the body part 3a toward the tip, and is constructed as a two-part body using an elastomer which is an elastic polymer material. As the elastomer material, a rubber-like elastic body having excellent weather resistance, aging resistance, heat resistance, and low temperature resistance is preferable.

In the space between the buffer body 3 and the cable 2 covered by the cable tube 2a, a synthetic resin layer 5 is formed in the body 3a as a low viscosity liquid by injecting it from the injection port 6 and hardening it. In addition, the inner peripheral surface of the lip-shaped portion 3b is compressed along the outer peripheral surface of the cable tube when the buffer main body 3 configured as a two-split body is assembled to prevent leakage when synthetic resin is injected. Easily deformable open-cell foam 4 , which can be combined into a truncated conical shape, is adhesively fixed, and a skin layer 4a is formed on the side surface in contact with the synthetic resin layer 5.

The apparent specific gravity of open cell foam 4 is 0.01 to 0.2
The range is preferably 0.015 to 0.1, particularly 0.015 to 0.1. If it is less than 0.01, it is too light and soft and cannot withstand the injection pressure of liquid synthetic resin. On the other hand, if it exceeds 0.2, it is too hard and has low compressive deformability, making it difficult to obtain smooth deformability and making work unstable and difficult. A suitable material for such a material is polyurethane foam with a skin layer formed thereon. 7 is an exhaust port for injecting liquid synthetic resin.

Examples of the liquid synthetic resin constituting the synthetic resin layer 5 include liquid hardened synthetic resins such as epoxy resins, unsaturated polyester resins, and polyurethane resins.

The work of attaching the cable to the cable is extremely simple; the open-cell foam 4 adhered to the inner circumferential surface of the lip-shaped portion 3b is pressed and compressed along the outer circumferential surface of the cable tube, and the buffer section main body 3 as a two-split body is assembled. After securing the combined state with the cover 1, pour the liquid synthetic resin into the space of the body 3a through the injection port 6.
The body and the cable pipe may be integrated by injecting the synthetic resin layer 5 into one body and curing it to form a synthetic resin layer 5.

FIG. 2 shows a cross-sectional view when the cable 2 is set in an eccentric state on the buffer body 3. When the cable 2 is set in an eccentric state, as shown in the figure, the lip-shaped part 3b is pressed by the cable. On one side, a pressure contact surface PF is formed, and on the other side, an eccentric opening is formed.
Form an EO. In this way, when both ends of the buffer main body 3 are opened wide due to eccentricity, it is impossible to completely prevent leakage when liquid synthetic resin is injected using a sealing material such as a sealant. .

Therefore, as a method that can cope with the variation in the position of the lip 3b and the cable, the open cell foam 4 is set in a compressed state between the lip 3b and the cable.

The degree of compression is variable because the maximum to minimum range of compression is determined by taking into consideration the state of occurrence of offset, the apparent specific gravity of the foam, the viscosity of the injected resin, etc. As an example of a case where the thickness of the open cell foam 4 is large, the thickness of the open cell foam 4 can be set to the space between the body 3a of the buffer body 3 and the cable pipe 2a when the cable is set at the center of the buffer body 3. It may be approximately twice as much as the actual value.

That is, the open-cell foam 4 adhered along the inner surface of the lip-like portion 3b is provided as a two-part body, and is combined into a truncated conical shape in a compressed state along the outer peripheral surface of the cable pipe 2a. The diameter of the bottom surface of the open cell foam 4 having a conical head shape is set to be approximately twice the diameter of the synthetic resin layer 5 filled in the space between the cable pipe 2a and the body portion 3a, in other words, the inner diameter of the body portion 3a. It is something to be considered. Note that this size range is usually based on a range of approximately 1.5 times to approximately 2 times, and may be varied to some extent depending on the situation. The skin layer 4a, which is formed at the interface with the synthetic resin layer 5 in order to suppress the penetration of the liquid synthetic resin, is formed by molding the foam.

Because of its low apparent specific gravity as mentioned above, this open cell foam is highly deformable and can be compressed to better accommodate any eccentricity that may occur. It goes without saying that the pressed surface part PF at the tip of the lip-like part 3b due to eccentricity has a sufficient leakage prevention function for high compression, but the eccentric opening EO has a sufficient leakage prevention function for moderate compression and skin layer 4a.
As a result, penetration of the liquid synthetic resin until hardening is suppressed, and leakage due to any eccentricity can be prevented.

Furthermore, even if uncured synthetic resin were to impregnate the cells of the open-cell foam 3 during the curing of the synthetic resin, the packing density of the synthetic resin would gradually decrease outwards and the leakage would be prevented. This is completely prevented, and the lip portion 3b is also set in a stable state with suitable strength and cushioning properties, and is in a state where it exhibits a suitable cushioning function.

In particular, when the inside of the lip-like part is formed of a composite of open-cell foam 3 and synthetic resin 5 impregnated therein, and the density of the synthetic resin gradually decreases toward the tip of the lip-like part 3b. In addition, the lip-like portion 3b also has the feature of forming a suitable buffer having stable strength.

[Effects of the Invention] As described above, the buffer device of the present invention can always obtain an effective leakage prevention effect of liquid synthetic reception that is injected and hardened, regardless of the size of the bias of the cable.
The cable and the shock absorber main body are bonded and integrated by a homogeneous synthetic resin layer, and a corner bending buffer device that can exert an effective corner bending buffering effect can be quickly implemented with good workability. It's something you get.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the cable-stayed bridge cable corner bending shock absorber according to the present invention, and FIG. 2 is a front view showing an embodiment in which the cable is set eccentrically with respect to the buffer main body. The sectional view shown in FIG. 3 is a front view showing a state in which the cable is fixed using the corner bending buffer device developed in the early stage, and is partially shown in cross section. FIG. 4 is a sectional view taken along the - line in FIG. 3. DESCRIPTION OF SYMBOLS 1...Cover, 2...Cable, 2a...Cable tube, 3 ...Buffer main body, 3a...Body part, 3b
...lip-shaped part, 4 ...open cell foam, 4a...
Skin layer, 5...Synthetic resin layer, 6...Inlet, 7
...Exhaust port, Bf...Buffer device, EO...Eccentric opening, PF...Press contact surface.

Claims (1)

[Scope of Claims] 1. A buffer main body that is a two-split body consisting of a cylindrical body that surrounds a cable covered with a cable tube, and a lip that tapers from the body to the tip. ; an open cell foam that is adhered to the inner peripheral surface of the lip-like part and combined in a compressed truncated conical shape along the outer peripheral surface of the cable pipe; and an open cell foam that is formed and filled in the space of the body and that is formed between the cable pipe and the trunk. and a synthetic resin layer integrated with the open cell foam, wherein the open cell foam has a skin layer on the interface with the synthetic resin layer.