JP2003055911A - Structure for saddle exit part of diagonal cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for the saddle exit part of a diagonal cable preventing concentration of bending stresses at a protective pipe, and allowing bending loads to be smoothly transmitted to an inner pipe. SOLUTION: The structure includes the inner pipe 4 positioned inside a main tower structure, and the diagonal cable 6 drawn out of the main tower structure through the inner pipe. Grout is packed between the inner pipe 4 and the diagonal cable 6. A slide pipe 80 is connected to the inner pipe 4 and the protective pipe 90 covering the diagonal cable 6 is connected to the slide pipe 80. The slide pipe 80 is formed thinner on its side connected to the protective pipe 90 than on its side connected to the inner pipe 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outlet structure of a saddle part in a main tower structure such as a cable-stayed bridge or an extra dosed bridge, and a slide pipe used for this structure. In particular, the present invention relates to a saddle portion outlet structure that can reduce the local concentration of the amplitude load of the diagonal cable and improve the durability of the diagonal cable.

[0002]

2. Description of the Related Art Generally, the saddle part of an extra-dosed bridge or the like holds the central portion of the diagonal cable, which has both ends fixed to the main girder, in the main tower structure and is buried in the main tower structure. The inner pipe is arranged inside the outer pipe, a plurality of diagonal cables (tension members) are penetrated through the inner pipe, and grout is filled between the inner pipe and the tension member ( For example, JP-A-8-170306).

In this saddle part, a slide pipe is connected to the inner pipe near the outlet where the diagonal cable is exposed from the inside of the main tower structure, and a protective pipe covering the outer periphery of the diagonal cable is connected to this slide pipe. Has been done. Conventionally, the wall thickness of this slide tube was formed uniformly in the longitudinal direction.

[0004]

The diagonal cable held in such a saddle portion is vibrated when a live load is applied or due to wind and rain to generate a bending load. However, the saddle structure using the conventional slide tube has a problem that its bending rigidity is not optimized.

If the bending rigidity of the slide pipe is too high (the steel pipe is thick), there is a problem in durability since the pipe is bent at the fitting portion with the protection pipe. Conversely, if it is too low (the steel pipe is thin), the bending load is not transmitted smoothly at the end of the inner pipe, and the axial amplitude load generated in the diagonal cable due to the bending load may locally concentrate.

Therefore, when a bending load is applied to the diagonal cable, the sliding pipe has a structure in which bending stress is not concentrated on the protection pipe at the connection portion between the slide pipe and the protection pipe (structure in which the protection pipe does not break). In addition, there has been a demand for a structure in which the bending load of the diagonal cable is smoothly transmitted to the inner pipe at the connection portion with the inner pipe in the saddle.

Therefore, a main object of the present invention is to provide a structure at a saddle outlet portion of a diagonal cable in which bending stress is not concentrated on a protective tube and a bending load is smoothly transmitted to an inner tube.

Another object of the present invention is to provide a slide pipe in which bending stress is not concentrated on the protective pipe and a bending load can be smoothly transmitted to the inner pipe.

[0009]

The present invention achieves the above object by changing the thickness of the slide pipe along the longitudinal direction.

That is, the structure of the saddle cable of the present invention at the saddle outlet is an inner pipe arranged inside the main tower structure, and a diagonal cable extending through the inner pipe to the outside of the main tower structure. A grout filled between the inner pipe and the diagonal cable, a slide pipe connected to the inner pipe, and a protection pipe connected to the slide pipe and covering the diagonal cable, the slide pipe being protected. The connecting side with the pipe is formed thinner than the connecting side with the inner pipe.

Further, the slide pipe of the present invention is a slide pipe whose one end side is connected to a protection pipe for covering a diagonal cable and whose other end side is connected to a saddle inner pipe. One end side of this slide pipe is closer to the other end side. Is characterized by being formed thin.

As described above, the slide pipe is formed so that the connecting side with the protective pipe is thinner than the connecting side with the inner pipe, so that the protective pipe side of the slide pipe is easily bent and the inner pipe side is It can be made a structure that is difficult to bend. Therefore, the bending load is greatly reduced as elastic energy by the cantilever effect of the slide pipe and is transmitted to the inner pipe. Further, local concentration of the axial amplitude load generated by bending vibration of the diagonal cable is reduced, and the durability of the diagonal cable is improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a partial cross-sectional view of a saddle portion of a main tower in an extra dose bridge using the water blocking structure of the present invention.

(Schematic Structure of Saddle Section) This saddle section is
An outer pipe 2 made of high-density polyethylene is embedded in concrete 1 that constitutes the main tower 100, a spiral reinforcing bar 3 is arranged on the outer periphery of the outer pipe 2, and an inner pipe 4 is provided inside the outer pipe 2. A steel pipe has been inserted. An inner pipe spacer 5 is placed between the outer pipe 2 and the inner pipe 4.
Holds the position of the inner pipe 4 in the outer pipe. A slide pipe is connected to the end of the inner pipe, and a protection pipe 90 is connected to the end of the slide pipe 80.

The inner tube 4 has a plurality of tension members (slanting cable) 6 penetrating inside. For the tension material, PC steel stranded wire having an epoxy resin coating on the surface is suitable. In FIG. 1, only one tension member 6 is illustrated and the other members are omitted.

Both ends of the inner pipe 4 are exposed from the concrete 1 of the main tower, a water-stop structure is formed at this outlet, and the space filled between the inside of the inner pipe and the tension member 6 is filled. Prevent grout leakage. Then, both ends of the tension member 6 that penetrates the main tower 100 are fixed to the main girder via fixing tools (not shown).

(Saddle Outlet) FIG. 2 is an enlarged sectional view of the saddle outlet. The outlet part comprises inner and outer tubes 2, 4 and a slide tube connected to their ends. A support plate 10 is attached to the outer circumference of the outer tube 2. The support plate 10 is a short tube portion 1 fixed by welding to the outside of the outer tube 2.
1 and a plate portion 12 that is continuous in a flange shape at one end of the short tubular portion 11. Then, the plate portion 12 has an inner pipe
A ring nut 7 screwed onto the outer periphery of 4 is screwed. A primary grout injection pipe 15 is connected to the inner pipe 4, and the injection pipe 15 passes through the outer pipe 2 to pass through the short tube portion 11 and further through the plate portion 12 to be drawn out to the outside.

Further, a spacer 20, a retaining plate 30, an elastic member 50, and a holding plate 60 are sequentially provided toward the outside at the outlet of the inner pipe to form a water-proof structure for the primary grout.

The slide pipe 80 is fixed to the surface of the ring nut 7 with a bolt so as to cover the water blocking structure. Hereinafter, each component will be described in detail.

(Outer Pipe 2 / Inner Pipe 4) The outer pipe 2 is an arcuate pipe buried in the concrete of the main tower, and is made of, for example, polyethylene. The inner pipe 4 is an arc-shaped pipe arranged inside the outer pipe, and for example, a steel pipe is used. The inner pipe 4 protects the diagonal cable 6 in the main tower portion, fills the inside with primary grout to prevent corrosion of the diagonal cable 6, and integrates the diagonal cable 6. Therefore, at the end of the inner pipe 4, a water stop structure for the primary grout is provided. Then, with this inner pipe 4, the diagonal cable 6
It bears the unbalanced load generated on the left and right of the body by friction.

(Slide Pipe 80) Slide Pipe 80
Is a pipe for connecting the main tower structure and the protection pipe 90 covering the diagonal cable 6 and filling the inside with the secondary grout. Usually, a steel pipe is used. This slide pipe 80
Figure 3 shows an enlarged cross-sectional view of the. As shown in this figure, the slide pipe 80 has a female screw portion 81 into which a protective pipe is screwed at one end.
A flange 82 for mounting on the plate portion 12 is formed at the other end, and a secondary grout discharge hole 83 is formed on the outer peripheral surface of the slide pipe adjacent to the flange 82. Here, the thickness of the female thread side (protection tube side) of the slide pipe is made thinner than that of the flange side (inner tube side).
That is, the bending rigidity of the slide pipe 80 is set to be substantially the same as the inner pipe 4 on the main tower side and lower at the connecting portion with the protection pipe 90. In this example, the thickness of the thick part 80A
The thickness of the thin portion 80B was 4.5 mm and 3.8 mm.

As described above, by changing the thickness of the slide pipe 80 in the longitudinal direction, the bending rigidity of the slide pipe 80 can be gradually reduced from the main tower side to the free length portion. As a result, the bending load is greatly reduced as elastic energy by the cantilever effect of the slide pipe and is transmitted to the inner pipe. Further, local concentration of the axial amplitude load generated by the bending load of the diagonal cable 6 is reduced, and the durability of the diagonal cable 6 is improved.

The method of changing the wall thickness of the slide pipe 80 in the longitudinal direction includes both changing the thickness stepwise and continuously changing the thickness. In this example, the thickness of the slide pipe 80 is changed in two steps, but in addition to this, the thickness may be changed over three steps or more, or may be changed in a continuous taper shape.

The dimensions of the slide pipe 80 used in this example are as follows. Overall length: 996mm Outer diameter of thick part: 216.3mm Outer diameter of thin part: 214.9mm Flange diameter: 300mm Flange thickness: 6mm Axial length of female thread: 126mm

(Protection Tube 90) The protection tube 90 is a pipe for protecting the diagonal cable 6 in the free length portion and filling the inside with the secondary grout. Generally, as the material of the protective tube 90, a material such as fiber reinforced plastic (FRP) or high density polyethylene is used. The secondary grout inside the protection tube is injected from the fixing tool side of the main girder, and the slide pipe
This is done by flooding the grout through the 80 discharge holes 83.

As shown in FIG. 4, at the end of the protective tube 90,
A male screw adapted to the female screw portion 81 of the slide pipe is formed. The end portion of the slide pipe 80 is formed in a tapered shape along the outer diameter of the protection pipe 90.

(Water Stopping Structure) <Spacer 20> A spacer 20 for holding a plurality of tendons 6 at predetermined intervals is fitted in the outlet portion of the inner pipe 4. As shown in FIG. 5, the spacer 20 is a columnar body that substantially corresponds to the inner diameter of the inner tube 4, and has a through hole 21 for each tendon 6 in the axial direction. Further, at one end of the spacer 20, there is formed a stopper portion 22 which is formed in a flange shape and prevents the spacer from entering the inside of the steel pipe by coming into contact with the end portion of the steel pipe. The spacer 20 may have any structure as long as it can hold the tendons 6 at predetermined intervals, and is preferably made of a material that is not easily worn by the friction when the tendons 6 are inserted. In this example, the spacer 20 is made of high density polyethylene.

<Retaining Plate 30> A retaining plate 30 is arranged outside the spacer 20. As shown in FIG. 6, the retaining plate 30 is a disc-shaped member having a tubular portion 31 at one end and a plate portion 32 at the other end. The plate portion 32 has a through hole 33 made of a tension material in the axial direction, and the tubular portion 31 has a resin filling hole 34 penetrating in the radial direction. The filling holes 34 are provided at a total of four positions at positions that divide the outer periphery into four substantially equal parts.

The outer diameter of the retaining plate 30 is substantially equal to the outer diameter of the inner tube 4 and is constant in the longitudinal direction, but the inner diameter of the tubular portion 31 is large on one end side and small through the step portion 35 from the middle. There is. The attachment to the end of the steel pipe is performed so that the tubular portion 31 faces the spacer 20. By this mounting, the stopper portion 22 of the spacer is fitted into the step portion 35, and the spacer 20 and the tubular portion 31
The space surrounded by and becomes the resin filling portion. The filling portion is filled with resin as described later.

Further, a total of six bolt holes 36 penetrating in the axial direction are formed on the outer peripheral side of the fastening plate 30. The bolt hole 36 is a hole through which a bolt 70 of a tightening mechanism described later is passed. In this example, the fastening plate 30 is made of high-density polyethylene.

<Elastic Material 50> The elastic material 50 is arranged outside the fastening plate 30. As shown in FIG. 7, the elastic member 50 is a disc-shaped member having a through hole 51 of a tension member. It is sandwiched between a retaining plate 30 and a pressing plate 60, which will be described later, and is compressed and deformed to seal between the elastic material 50 and the tension material 6 to suppress resin leakage. The elastic material 50 is preferably made of a material that is appropriately elastically deformed and is less likely to be worn by the friction when the tendon is inserted. Ordinary chloroprene rubber and urethane rubber are often insufficient in terms of wear resistance. In this example, elastic material
The material of 50 is Hanenite (trade name), which has excellent wear resistance when inserting a tension material.

<Pressing plate 60> The pressing plate 60 is provided outside the elastic material 50.
Are placed. The holding plate 60 is also a disc-like member having through holes 61 for the tension members 6, as shown in FIG. Presser plate 6
A recess 62 into which the elastic material 50 is fitted is formed on one end side of 0.

Further, a total of six bolt holes 63 penetrating in the axial direction are formed on the outer peripheral side of the holding plate 60. The bolt hole 63 is a hole through which a bolt 70 of a tightening mechanism described later is passed.

In this example, the size of the holding plate 60 is 45 mm in thickness,
The outer diameter is 160 mm and the material is high density polyethylene.

<Clamping Mechanism> A clamping mechanism is used to compress and deform the elastic material 50. In this example, the retaining plate 60 and the retaining plate 30
A bolt 70 (see FIG. 2) that sequentially penetrates through and is screwed into the end surface of the opening of the inner tube 4 is used. That is, the bolt 70 is penetrated through the bolt holes 36 and 63 of the retaining plate 30 and the retaining plate 60, and the retaining plate 60 is pressed against the spacer side by tightening the bolt 70, and a compressive force is applied between the retaining plate 30 and the retaining plate 30. Let The elastic material 50 is deformed by this compressive force and seals between the elastic material 50 and the tension material 6.

<Resin> The resin filled in the resin-filled portion is preferably a fast-acting resin that cures in a short time. The resin filling surely prevents the grout from leaking from the retaining plate 30. This resin is preferably a resin which is quickly filled in the gap between the tension member 6 and the spacer 20 and the gap between the retaining plate 30 and the tension member 6 and has an appropriate viscosity such that it does not easily flow out. In this example, the viscosity is 50 ~ 90Pa at 25 ℃
・ S epoxy resin was used.

<Assembly Method of Water Stop Structure> An assembling method of the water stop structure will be described. After inserting all the tension materials into the steel pipe, spacer 20, retaining plate
Slide 30, elastic material 50, and pressing plate 60 to draw them toward the saddle. This pulling can be done manually, but if it is difficult to slide manually, a lever block may be used. For example, an annular drawing jig (not shown) is arranged on the outside of the holding plate 60, the drawing jig and the ring nut 7 are connected by a chain attached with a lever block, and the lever block is operated to operate the spacer. 20, retaining plate 30,
Slide the elastic material 50 and the pressing plate 60 to the ring nut side.

The spacer 20 is inserted into the steel pipe. If it is difficult to insert it, the tension member 6 may be lifted slightly.

[0039] Further, the retaining plate 3 is sequentially provided on the outer side of the spacer 20.
The 0, the elastic member 50, and the holding plate 60 are arranged so as to be in contact with each other.

Bolt holes 6 in the holding plate 60 and the retaining plate 30
Insert the bolt 70 into the screws 3 and 36, screw the tip of the bolt 70 into the end surface of the inner pipe 4, and tighten the holding plate 60. By interposing a spring washer or a flat washer on the bolt head, the bolt head does not bite into the holding plate 60 and tightening is not insufficient. By this tightening, the elastic material 50 is compressed until the thickness thereof becomes about half. The compressed elastic material 50 deforms so as to expand and seals between the elastic material 50 and the tension material 6.

A jack is attached to the tension member 6 to tension the tension member 6 to a predetermined pressure.

Resin is injected from the resin filling hole 34 of the fastening plate. At this time, the resin is injected from the lowest filling hole of the four resin filling holes 34, and the resin is overflowed from the remaining three filling holes to sufficiently fill the resin. By this work, the retaining plate 30 and the spacer
Resin is filled in the space surrounded by 20 and the gap between the retaining plate 30 and the tension member 6.

After the resin is hardened (about 24 hours after the injection), grout is injected and filled from the injection pipe 15 into the saddle steel pipe.

Grout is injected into the steel pipe. This injection is performed through the injection pipe 15 exposed from the support plate 10. This grout injection prevents the tendon 6 from sliding in the saddle.

[0045]

As described above, in the slide pipe of the present invention and the saddle structure using the same, the bending load of the diagonal cable is greatly reduced as elastic energy due to the cantilever effect of the slide pipe, and the internal pipe is Transmitted.
That is, the bending load of the diagonal cable can be smoothly transmitted to the inner pipe at the connection portion with the inner pipe in the saddle. In addition, at the connecting portion between the slide pipe and the protective pipe, bending stress can be prevented from concentrating on the protective pipe.

[Brief description of drawings]

FIG. 1 is a schematic view of a saddle structure of a main tower.

FIG. 2 is a cross-sectional view of the structure at the saddle outlet of the diagonal cable of the present invention.

FIG. 3 is a sectional view of the slide pipe of the present invention.

FIG. 4 is a cross-sectional view showing a connecting portion between a slide pipe and a protection pipe.

FIG. 5A is an end view of the spacer, and FIG. 5B is a longitudinal sectional view thereof.

FIG. 6 (A) is an end view of the fastening plate, and FIG. 6 (B) is a longitudinal sectional view thereof.

FIG. 7A is an end view of the elastic material, and FIG. 7B is a longitudinal sectional view thereof.

FIG. 8A is an end view of the presser plate, and FIG. 8B is a vertical sectional view thereof.

[Explanation of symbols]

1 concrete 2 outer tube 3 reinforcement 4 inner tube 5 Inner tube spacer 6 Tension material 7 ring nut 10 Support plate 11 Short section 12 Plate part 15 injection pipe 20 spacer 21 through holes 22 Stop 30 retaining plate 31 Cylindrical part 32 Plate 33 through hole 34 Resin filling hole 35 step 36 bolt hole 50 elastic material 51 through hole 60 Presser plate 61 through hole 62 recess 63 bolt hole 70 volts 80 slide pipe 81 Female thread 82 flange 83 Discharge hole 90 protection tube

Claims (2)

[Claims] [Claim 1] An inner pipe arranged in the main tower structure, a diagonal cable penetrating through the inner pipe and drawn out of the main tower structure, and a space between the inner pipe and the diagonal cable A grout, a slide pipe connected to the inner pipe, and a protection pipe connected to the slide pipe to cover the diagonal cable, wherein the slide pipe has a connection side with the protection pipe more than a connection side with the inner pipe. The structure at the saddle exit of the diagonal cable, which is characterized by being formed thin. 2. A slide pipe, one end of which is connected to a protection pipe for covering a diagonal cable and the other end thereof is connected to a saddle inner pipe, wherein one end of the slide pipe is formed thinner than the other end. A slide pipe characterized in that.