JPH11323823A - Suspension equipment for construction structures - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a simple and effective method for solving the problem of tangential force applied to a suspension cable. A suspension device includes at least one suspension cable and a suspension member attached to the suspension cable by a collar. The suspension cable comprises a bundle of strands 6 which are fixed at both ends and are pulled by the load of the structure transmitted by the suspension member 4, and a jacket structure 10 including these strands and having a collar 13 attached thereto. , 12 are provided. This jacket structure has sufficient compressive strength to absorb the tangential component of the force that the collar exerts on this cable, with the suspension transmitting the load with little transmission of the clamping force to the strand. It has in the direction parallel to this suspension cable. Since these strands are individually protected,
Can be replaced one by one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension type construction structure, and more particularly to a suspension bridge or a suspension cover.

[0002]

2. Description of the Related Art Generally, a device for suspending such a structure is connected to at least one suspension cable having both ends fixed and a collar fixed around the suspension cable. And a hanging material. The suspension transmits the load of the structure to the suspension cable. In most cases, the hanger is not necessarily perpendicular to the hanger cable, so that at least some of the collars have a force that has a tangential component to the hanger cable, called the tangential force. Will be given to.

[0003] Usually, a suspension cable is composed of a bundle of bare steel wires or strands.
It is covered with an outer protective layer of paint or bitumen or a tubular covering. This protective layer is generally interrupted at the longitudinal position of the collar which is tightly fastened directly to the steel wire of the suspension cable.

The extremely tight fastening of the collar satisfies the following two main functions. 1) The tangential force received by the collar is received by friction.
That is, at low levels of the steel-to-steel coefficient of friction, the clamping force of the collar must be correspondingly high. 2) The relative movement between the pulled wires (steel wires or wires) constituting the suspension cable is reduced as much as possible. It is because these strands are bare, and their relative movement causes wear and fatigue due to "fretting corrosion" (fatigue or wear caused by minor slippage), which causes the collar to relax and This is because the wire of the part may be destroyed.

[0005]

SUMMARY OF THE INVENTION These prior art suspension structures have the following problems. 1) Extremely tight collars require very long (eg, up to 2 meters) and heavy collars to be tightened with many bolts. 2) The effect of "fretting corrosion" cannot be completely prevented. 3) It is often observed that corrosion spreads under the outer protective layer of the cable.

[0006] In EP-A-0 789 110, a mold is inserted between the superposed layers of the strands of the suspension cable inside the collar, so as to fill the gap between the strands. It has been proposed to improve the homogeneity of the tightening. These inserts, when placed beneath the collar, transmit this clamping force around the entire circumference of the strand, almost hydrodynamically, rather than concentrating the clamping force on the line where the strands contact each other. .

[0007] In French Patent No. 2 739 112, the collars are connected to each other by an auxiliary connecting cable so as to reduce the force of clamping the collar on the suspension cable, ie to compensate for the static part of the tangential force due to the nominal load on the structure. Strategies for connecting are described. Dynamic parts (overloads that fluctuate due to traffic, climatic conditions, etc.) are caught by the force tightening the collar on the suspension cable. This process requires a continuous connecting cable that is pulled according to the specified tension.

A first object of the present invention is to provide a simple and effective way to address the problem of tangential force on a suspension cable.

[0009]

SUMMARY OF THE INVENTION The present invention provides at least one
A suspension device for a construction structure, comprising a suspension cable of a book and a suspension attached to the suspension cable by a collar. This suspension cable contains a bundle of strands that are fixed at their ends and are pulled by the load of the structure transmitted by the suspension, and these strands,
A jacket structure to which a collar is attached on the outside thereof. According to the present invention, the jacket structure has sufficient compressive strength in the direction parallel to the suspension cable to receive the tangential component of the force exerted on the cable by the collar when the load is transmitted by the suspension material. However, it does not substantially transmit any tightening force to the strand.

This tangential force is absorbed by longitudinal compression of the jacket structure, rather than by friction against the strand being pulled. As a result, the tightening on the collar will not be transmitted to the strand,
Or can be significantly reduced. Many of the disadvantages of suspended structures found in the prior art due to extreme tightening of the collar can be eliminated in this way. In particular, it is avoided to apply a strong squeezing force under the collar to the strand being pulled, which improves the durability of the cable.

It is worth noting that the presence of the strand being pulled inside the jacket structure gives the jacket structure a strong resistance to buckling. This characteristic is similar to that of the outer cylinder of a bicycle brake cable. That is, when the brake handle is operated, both ends of the outer cylinder are strongly compressed. However, since the outer cylinder includes the cable that is being pulled, the outer cylinder has a good buckling resistance.

One major advantage of the present invention is that the wires can be pulled out and replaced one by one without having to remove the collar, which means that these wires can be crushed under their respective collars. Because there is no. This allows the following: 1) Sometimes one or more strands are pulled out and tested to see if they can be taken out and analyzed to diagnose potential degradation. 2) If the wires are worn or corroded and the suspension cables have to be replaced, the wires can be replaced one by one, whereby the second cable can be replaced before the first cable is removed. There is no need to attach cables. For existing structures, if you try to attach a second cable,
The exchange operation is particularly complicated.

In a preferred embodiment, the jacket structure of the suspended cable has an outer tube, a separate outer coating enclosing the strands of the cable, and a lubricant, and the outer tube is independent of the outer tube. The space between them is filled with the cured fill product. This effectively protects these strands from corrosion and the effects of "fretting corrosion". The cured fill product forms a base around these strands that resists longitudinal compression to receive tangential forces.

In a particular embodiment: 1) The strands being drawn are metallic and coated with grease or wax making up the above-mentioned lubricant, or alternatively, these strands But,
Grease or wax coated metal, each strand may be encased in a first coating made of a plastic material and itself housed in a separate outer coating with lubricant in between . 2) The independent outer sheath of the strand has bulges spaced along the direction of the cable. 3) The outer tube of the cable has an inner surface provided with lateral undulations in at least some longitudinal positions of the plurality of collars. 4) The outer tube of the cable has an outer surface provided with lateral undulations in a longitudinal position of at least a portion of the plurality of collars, the collar being adapted to engage over the outer tube. It has a rough undulation. 5) The outer tube of the cable is transversely welded to a smooth section extending between the collars at a longitudinal position of at least a portion of the collar referred to in either or both of the preceding two sections. It has sections with directional relief.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a suspension bridge will be described with reference to the drawings.

Conventionally, the suspension bridge shown in FIG. 1 is composed of a deck 1, two towers 2, two parallel suspension cables 3 (only one is shown in the figure), and a suspension that is connected to the suspension cables 3 and supports the deck 1. Material 4 is provided.

A suspension cable 3 is provided at each end of the bridge by two ground anchors 5 (ie, artificial anchoring blocks, rock anchors, or, in the case of a "self-fixed" suspension bridge, at both ends of the deck, if necessary). (Anchor) and are supported by tower 2. It is desirable that the suspension cables 3 are fixed to the towers 2 at the positions of the towers 2 in the longitudinal direction and are discontinuous.

Each suspension cable 3 includes one or a plurality of bundles of independent protective strands 6, one example of which is shown in FIG.

Inside each of the independent protective strand groups 6, the actual strands 7 form a member that is effective during traction. The strand 7 is composed of a plurality of (seven in the illustrated example) twisted steel wires. This steel wire is corrosion resistant (galvanized, zinc-aluminum alloy coating, etc.)
May have been given. The strands 7 are embedded in a lubricating material 8 which is itself covered by an outer covering 9 made of a flexible plastic material such as, for example, high density polyethylene (HDPE). The lubricating material 8 also protects the steel of the wire from corrosion. The lubricating material 8 is generally grease or wax.

The group of independent protective wires 6 of the suspension cable 3 is housed in an outer tube 10 extending over the entire length between the fixed ends of the suspension cable 3. The cured filling product 12 fills the remaining space between the outer tube 10 and the outer sheath 9 of the strand (see FIG. 2). The outer tube 10 may be made of a metal or a plastic material such as HDPE. The cured fill product 12 may be a cement grout, a polymer or a resin.

The lower end of each suspension member 4 is fixed to the deck 1 of the bridge, and the upper end thereof is fixed to the suspension cable 3 by a collar 13. Each collar 13 is bolted together around the suspension cable 3, for example 2
Two semi-cylindrical bushes 13a and 13b,
The upper end of the suspension member 4 is articulated to one of the two bushes 13a.

The jacket structure enclosing the strands 7 of the suspension cable 3 comprises independent outer jackets 9 of these strands, but each collar transmitting the load on the individual suspension 4. The transmission of the crushing force generated by the fixing to the strands 7 is prevented by the base formed by the cured filling product 12 and by the outer tube 10.

The tangential force generated when the suspension member 4 is not perpendicular to the suspension cable 3 is received by the jacket structure because its compressive strength acts in parallel with the direction of the suspension cable. By filling the material 12 such as cement grout or resin, the required compressive strength on the order of tens of MPa can be easily obtained. Alternatively, the material 12 may be a grout with an increased amount of resin.

In order to attach the suspension cable 3, the external tube 10 through which one independent protective element group 6 penetrates
You need to start with The metal wires 7 of the wire group 6 are fixed at both ends of the suspension cable 3. Then, another group of independent protective strands 6 is passed one after another by being pulled with the help of a shuttle sliding alternately in the tube 10 in the opposite direction. Each time a strand is passed, both ends are fixed. When all of the independent protective strands 6 have been passed and fixed, the filling product 12 is injected into the tube 10 from the lowest point of the path of the suspension cable 3. The injection is carried out at high points, i.e. under pressure, with vents in the fixing device attached to the tower 2 of the bridge. After the injected filling product 12 has hardened, the hanger 4 can be started to be connected by its collar 13.

The tensioned wire 7 of the suspension cable
Can be replaced individually without removing the collar 13, for example as follows. First, we start by welding the end of a new strand to the first end of the previously used strand 7 projecting from one of the fixed blocks. Next, the fixing jaw is removed from the first end of the wire 7 after recording the tension of the wire. This strand is relaxed. Next, against the second end of this strand 7 projecting from the opposite fixing block, the fixing jaws are withdrawn and the second end of the strand 7 is completely removed from this independent outer sheath 9. Pull out and replace with a new wire until it is removed. Next, the wire is pulled by a jack to increase the tension value and then fixed. The wire can be easily pulled out by the lubricant 8 in the independent outer coating 9. Lubricants such as grease are brought in as new strands are introduced into the outer jacket 9, which performs the function of penetration, protecting the new strands from corrosion and facilitating subsequent replacement. .

Thus, the wires 7 of the suspension cable 3
Can be exchanged in a simple manner without interrupting the normal traffic of the bridge.

FIG. 4 shows another example of the independent protection element group 16 that can be used in the suspension device according to the present invention. The actual wire 7 is coated with a protective material 18 such as wax or grease, for example, as shown in FIG. It is surrounded by one coating 19. This first coating 1
Lubricant 20 such as grease exists between 9 and external coating 21 of independent protection element group 16.

The suspension cable 3 with the independent protective strands 16 shown in FIG. 4 can be attached in the manner already described. In order to replace the wires, the outer sheath 21
While remaining in place in the substrate formed by the filling product 12, the strand 7, the protective material 18 and the first coating 19
Is replaced by a similar unit.

By using the group of independent protective strands 16 shown in FIG. 4, the metal wire of each strand which is installed in place of the previous strand is completely covered with a layer of protective material 18,
Unwanted particles can be protected from contacting these metal wires during the exchange operation.

FIG. 5 schematically shows the structure of another group of independent protective wires 24 which can be used in the device of the present invention. This strand group 2
The outer coating 25 of the fourth has bulges 26 at intervals in the direction along the suspension cable 3. The spaced bulges 26 are arranged so that when the independent protective strands 24 are placed in the outer tube 10 of the cable, they are offset longitudinally from one another. In this way,
Spacing is provided between the outer coatings 25 of these strands, which allows the injected filling product 12 to pass properly between all the independent protective strands 24 and to be harmonized after curing. Can form a solid base.

To ensure that the tangential force is transmitted from the collar to the jacket structure of the suspension cable 3, the collar 13 is gently tightened (this force is not transmitted to the wire 7 being pulled). The friction force may be used. At the longitudinal position of the collar where such a tangential force acts, the outer tube 1 of the cable 3
The advantage of the present invention can be obtained by providing a lateral undulation on the inner surface and / or outer surface of the zero. Very little or no force is required to tighten the collar in the radial direction.

An external tube 10 of this type is shown in FIGS. The tube 10 is comprised of a smooth section 30 extending between the collars and sections 40, 50 and 60 located within the collar 13. The sections 40, 50 and 60 are welded end-to-end to the smooth section 30. These sections are formed by casting during the manufacturing stage, while the smooth section 30 is conventionally made by extrusion.

In the example of FIG. 6, the outer surface of the tube section 40 has a circumferential spline 41 and the inner surface of the collar 13 has a corresponding spline 42 for engaging the tube 10, thereby providing a tangential force. To communicate.

In the example of FIG. 7, the wall of the tube section 50 has a bellows-like waveform, thereby forming lateral undulations 51, 52 on the inner and outer surfaces. The tangential force exerted by the collar 13 having a corresponding groove 53 on its inner surface is transmitted almost directly to the hardened filling material in the tube 10.

In the example of FIG. 8, the tube section 60 has a spline 61 on its inner surface, which transfers tangential force to the cured filling material injected into the tube 10. An annular protrusion 62 is formed on the outer surface of the tube section 60, and an inner surface of the collar 13 is formed with an annular groove 63 which engages with the protrusion 62 to transmit a tangential force.

[0036]

As described above, since the jacket structure for receiving the tangential force is provided, the tightening force of the collar on the strand can be reduced, and the effect on the strand can be reduced.

Also, since the wires can be pulled out one by one, the state of deterioration can be diagnosed, and the wires can be replaced one by one, so that the second cable is prepared when the suspension cable is replaced. No need to do.

[Brief description of the drawings]

FIG. 1 is a general schematic diagram of a suspension bridge.

FIG. 2 is a cross-sectional view of a collar connecting a suspension cable and a suspension member of the suspension device according to the present invention.

FIG. 3 is a cross-sectional view of one example of a group of wires that can be used in the suspension device according to the present invention.

FIG. 4 is a cross-sectional view of another example of a group of wires that can be used in the suspension device according to the present invention.

FIG. 5 is a schematic side view of a group of wires that can be used in the suspension device according to the present invention.

FIG. 6 is a schematic longitudinal sectional view of an outer tube of a suspension cable usable in the suspension device according to the present invention.

FIG. 7 is a schematic longitudinal section of an outer tube of a suspension cable usable in a suspension device according to the invention.

FIG. 8 is a schematic longitudinal sectional view of an outer tube of a suspension cable usable in the suspension device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deck 2 Tower 3 Suspended cable 4 Hanging material 5 Anchor 6, 16, 24 Independent protective strand group 7 Actual strand 8 Lubricant material 9, 21, 25 Outer coating 10 Outer tube 12 Cured filling product 13 Collar 13a, 13b Bush 18 Protective material 19 First coating 20 Lubricant 26 Swelling 30 Smooth section 40, 50, 60 Tube section 41, 42, 61 Spline 51, 52 Undulation 53 Groove 62 Ring projection 63 Ring groove

Claims (8)

[Claims] At least one suspension cable, and a suspension member attached to the suspension cable by a collar, wherein the suspension cable has both ends fixed and a load of a structure transmitted by the suspension member. A hanging device for a construction structure, comprising: a bundle of strands that are tensioned by the above, and a jacket structure that includes the strands and has the collar attached to the outside, wherein the jacket structure includes: The collar has sufficient compressive strength in a direction parallel to the suspension cable to receive a tangential component of a force exerted on the suspension cable by the collar due to the load transmitted by the suspension member; A suspension device for a construction structure, which does not substantially transmit a clamping force to a wire. 2. The jacket structure comprises an outer tube, a plurality of independent outer coatings each containing a strand of the cable and a lubricant, and between the outer tube and the independent outer coating. And a cured filling product occupying the space described in claim 1. 3. The suspension device for a construction structure according to claim 2, wherein the strand is made of metal and coated with grease or wax constituting the lubricant. 4. The wire is a metal to which grease or wax is applied, and each of the wires is covered with a first coating made of a plastic material, and the first coating is made of a lubricant. 3. The suspension device for a construction structure according to claim 2, wherein the suspension device is housed in a filled independent outer covering. 5. The construction structure according to claim 2, wherein the independent outer covering has a plurality of bulges each spaced along the direction of the suspension cable. Hanging equipment. 6. The outer tube according to claim 2, wherein the outer tube has an inner surface with a lateral undulation at a longitudinal position corresponding to at least a part of the plurality of collars. A suspension device for a construction structure according to claim 1. 7. The jacket structure comprises an outer tube having a laterally undulated outer surface at a longitudinal position corresponding to at least some of the plurality of collars, wherein the collar itself is provided. 7. A suspension device for a construction structure according to any one of the preceding claims, having a corresponding undulation for engaging the outer tube. 8. The outer tube has a section with lateral undulations in a longitudinal position corresponding to the collar, the section being welded to a smooth section extending between the collars. A suspension device for a construction structure according to claim 6.