JPH0478761B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to an improvement in a cable installation method.

(Prior Art) Conventionally, in the cable installation of a suspended structure such as a cable-stayed bridge, the following method has been adopted as a method for pulling the cable to an anchoring point. That is, a pull rod having a thread on the outer periphery is screwed onto one end of the cable, and with the other end of the cable fixed to the structure at the location where it is to be installed, the pull rod is attached to the bearing plate for the end and the guide. After passing through the member and applying tension to the cable via the pull rod with a jack, the terminal fitting is locked to the bearing plate. This method has the problem that a large amount of deflection occurs in the cable due to its own weight, so a large tension force is required to pass the pull rod through the guide member, and the pull rod must also be long.

Therefore, as a means to reduce the force required to pull the pull rod to the guide member, as shown in FIG. The cable 1 is supported by a truck crane 14 to reduce the slack from the state shown by the imaginary line to the state shown by the solid line, thereby reducing the amount of retraction Δl to the cable tension length l as much as possible. 20 is brought closer to digit 13. In addition, as shown in FIG. 11, when an erection member 15 is stretched above the cable 1 to support the middle part of the cable 1, or when the girder 13 is constructed by an overhang method, the jack 16 A method has also been adopted in which the end of the girder 13 is raised higher than a predetermined position to reduce Δl. These methods themselves require extra equipment and work;
Also, the pull rod needed to be quite long. Furthermore, in the conventional method, a locking member that utilizes the frictional resistance of the contact surface is used as a means for locking the strand as a temporary drawing wire, so there is a problem that the drawing operation is not reliable. That is, during cable installation, it is inevitable that the strand will be scratched or rusted on its surface, which will significantly change the coefficient of friction of the contact surface between it and the locking member. In addition, since there is a difference in tensile stress between multiple strands, the pressure force of the locking member is not constant, which causes variations in frictional resistance (locking force). This causes the locking member to slip. These slips can cause the cables that are being installed to collide with other structures, creating a dangerous situation, so in the past, very time-consuming management was required to prevent slips.

(Purpose of the invention) This invention was made against this technical background, and it does not require any extra work as in the conventional method, and the length of the pull rod can be significantly shortened compared to the conventional method. The present invention provides a method that can reliably prevent slips.

(Structure of the Invention) The first invention is to screw a pull rod having a thread on the outer periphery to one end of the cable, and to attach the pull rod with the other end of the cable fixed to a structure at a position where the cable is to be installed. In this method, the cable is passed through the bearing plate for the terminal tool and the guide member, tension is applied to the cable via the pull rod by a jack, and then the terminal tool is locked to the bearing plate. Connect a thin temporary retracting bolt, attach a nut to the temporary retracting bolt, and pull the pull rod into the guide member through the locking member and the temporary retracting bolt with the above-mentioned jack. Tension is applied to the cable via a pull rod using a jack.

The second invention is to screw a pull rod having a thread on the outer periphery to one terminal of the cable, and attach the pull rod to the terminal fitting bearing while the other end of the cable is fixed to a structure at a position where the cable is to be installed. In this method, the cable is passed through the plate and the guide member, and tension is applied to the cable via the pull rod using jacks, and then the terminal fitting is locked to the bearing plate. Connect the PC steel stranded wire,
Stoppers that protrude like flanges on the outer periphery are fixed to this PC steel stranded wire at predetermined intervals, and the pull rod is pulled into the guide member via the locking member and the temporary pulling PC steel stranded wire by the above-mentioned jack, and then by the jack. Tension is applied to the cable via a pull rod.

A third invention is to screw a pull rod having a thread on the outer periphery to one terminal of the cable, and attach the pull rod to a terminal fitting bearing while the other end of the cable is fixed to a structure at a position where the cable is to be installed. In this method, the cable is passed through the plate and the guide member, and tension is applied to the cable via the pull rod using jacks, and then the terminal fitting is locked to the bearing plate. The wire rods are connected, a locking member mechanically coupled to the wire rod is attached to the temporary lead-in wire rod, and a plurality of wire rods having different wire diameters are sequentially thinned from the pull rod side to the other side as the wire rod. Using the above-mentioned jack, the pull rod is pulled into the guide member via the locking member and the temporary lead-in wire, and then the jack is used to apply tension to the cable via the pull rod.

(Function) In the first invention, a completely mechanical connection is used, such as the screwing of a bolt and a nut, and in the second invention, the fixation of a stopper projecting like a brim on the outer periphery, which reduces friction. Unlike the case of resistance, retraction operation can be performed reliably. In addition, in the third invention, a plurality of wires having different diameters are connected to each other so as to become thinner from the pull rod side to the other side as the temporary lead-in wire, so that the cable does not deform when it is pulled in. Big at first;
In response to the gradual decrease in size, bending deformation occurs accordingly.

(Example) FIG. 1 shows an apparatus used for carrying out this invention,
One end of the pull rod 2 is connected to the terminal fitting 20 of the cable 1 via a coupler 17.
An anchor head 68 at one end of the temporary lead-in wire (medium-diameter bolt) 6 is connected to the other end via a coupler 21, and a temporary lead-in wire (small-diameter bolt) 9 is further connected to the other end of the medium-diameter bolt 6. Anchor head 9 at one end of
1 are connected via a coupler 69. The medium diameter bolt 6 is formed of a bolt thinner than the pull rod 2.

The bearing plate 3 to which the terminal tool 20 is finally fixed has a hole 30 through which the terminal tool 20 passes, and a bolt hole 31 for connecting the guide member 4 around the hole 30. The guide member 4 consists of a pair of side plates 41, an end plate 42, and two intermediate plates 43, each of which has a hole 40 through which the pull rod 2 passes. A bolt fitting part 45 is formed, and the guide member 4 is coupled to the bearing plate 3 by fitting a bolt 47 into the bolt fitting part 45 and screwing it into the bolt hole 31. Further, a jack 5 is coupled to the end plate 42 of the guide member 4 by a bolt 46 passing through a bolt hole 44.

A first nut 99 screwed into the pull rod 2 and locking means 7 for the wires 6, 9 are arranged between the end plate 42 and the intermediate plate 43 of the guide member 4.
This locking means 7 includes a support plate 72 having a hole 73 through which the small-diameter bolt 9 and the medium-diameter bolt 6 pass, a nut 74 screwed onto the small-diameter bolt 9, and a nut 75 screwed onto the medium-diameter bolt 6. It is made up of.
As shown in FIG. 2, a nut 75 screwed onto a medium diameter bolt 6 passing through a hole 73 is supported by a support plate 72. Small diameter bolt 9 is in hole 73
When the nut 74 is penetrated through the support plate 72, the nut 74 screwed therein is supported by the support plate 72 via the nut 75. The reason why the plurality of holes are formed in the support plate 72 is to use them when a plurality of temporary lead-in wires are connected to the pull rod 2.

In addition, at the other end of the pull rod 2, there is a temporary lead-in wire 6,
9, a medium-diameter PC steel stranded wire 60 and a small-diameter PC steel stranded wire 90 may be used as temporary lead-in wires, in which case the anchor head 63 at one end of the medium-diameter PC steel stranded wire 60 connects the coupler 21. A small diameter PC steel strand wire 90 is coupled to the other end of the medium diameter PC steel strand wire 60 via a coupler 69. In addition, the medium diameter PC steel stranded wire 60 has stoppers 6 at predetermined intervals.
1 is fixed to the wire 90, and stoppers 93 are fixed to the small diameter PC steel stranded wire 90 at predetermined intervals. As shown in FIG. 3, this temporary lead-in wire is inserted into the support plate 72 through the stopper 61 through the hole 73 in the support plate 72 and through the annular washer 62 made of a pair of members.
We aim to be supported by the following.

The jack 5 has a hole 50 through which the pull rod 2 passes.
A second nut 19 that is screwed onto the pull rod 2 and a locking means 8 are arranged on the end face of the piston rod 51, and the locking means 8, like the locking means 7, has a small diameter bolt. 9 and a support plate 82 having a hole 83 through which the medium-diameter bolt 6 passes, and a nut 84 and a medium-diameter bolt 6 screwed onto the small-diameter bolt 9.
It consists of a nut 85 that is screwed onto the.

Next, a cable tensioning method using the above device will be explained. First, one end of the cable 1 is fixed at a predetermined position on the tower 11 as shown in FIG. The cable 1 is fixed at a predetermined position, and the end of the cable 1 is pulled using a winch (not shown) to pass the small diameter bolt 9 through the guide member 4 and the jack 5.

During the above-mentioned drawing, the cable 1 sag (sag H) due to its own weight, which causes bending deformation in the temporary drawing wire. This deformation becomes larger as the amount of drawing of the temporary drawing wire is smaller (the radius of curvature R is smaller), that is, the amount of deformation becomes smaller as the amount of drawing increases. In any case, bending stress continuously acts on the wire for temporary drawing, and accordingly, in order to smoothly draw the wire, a corresponding bending deformation must occur. For example, when the length L of the cable 1 is about 200 m, it is necessary that the bending deformation occurs with a radius of curvature R of about 3000 mm. Therefore, it is necessary to set the temporary lead-in wire to a thickness that will cause this degree of bending deformation, and for this reason, the temporary lead-in wire is set to be thinner than the pull rod 2 as described above.

As shown in FIG. 5, while the small diameter bolt 9 is held by the locking means 7 and 8, the jack 5 is driven to project the piston rod 51 into the state shown in FIG. 6, and from this state it is engaged. After the locking means 7 is retracted to a position where it contacts the nut 99 and the piston rod 51 is retracted, the locking means 8 is brought into contact with the end surface of the piston rod 51. By repeating this operation, the small diameter bolt 9 is intermittently retracted by one stroke of the piston rod 51, and subsequently the medium diameter bolt 6 is also retracted in the same manner. In this operation, the locking means consists of a nut mechanically connected to the wire and a support plate that supports it, so unlike conventional chucks, problems such as slipping occur due to frictional contact. There is no risk of this occurring, and reliable operation can be performed.

When the tip of the pull rod 2 passes through the intermediate plate 43, the nut 99 is screwed onto the pull rod 2 and the nut 8 screwed onto the medium diameter bolt 6, as shown in FIG.
5 and nut 99 to retract the piston rod 51 one stroke at a time.
When the tip of the pull rod 2 protrudes from the jack 5, loosen the coupler puller 21 and remove the medium diameter bolt 6.
As shown in FIG. 8, a nut 19 is screwed onto the tip of the pull rod 2. Then, by operating the jack 5, pull the pull rod 2 with the nuts 19 and 99, and when the terminal tool 20 reaches the predetermined position as shown in FIG. 3, the guide member 4 and pull rod 2 are each removed.

The above operation is performed using the medium diameter bolt 6 as a temporary lead-in wire.
Although the case where the small-diameter bolt 9 is used has been described, the same applies to the case where the medium-diameter PC steel stranded wire 60 and the small-diameter PC steel stranded wire 90 are used. Furthermore, instead of using the medium-diameter bolt 6 and the small-diameter bolt 9 connected in series, a plurality of small-diameter bolts 9 may be used in parallel. Of course, in this case as well, it is possible to cope with the bending deformation imparted to the temporary drawing wire during drawing.

(Effects of the Invention) As explained above, the present invention connects a temporary lead-in wire having a diameter smaller than that of the pull rod to the end of the pull rod, and mechanically connects a locking member to the wire. The cable is attached as shown in the figure, and tension is applied to the cable using jacks. Temporary retraction until retraction by the pull rod can be performed using the same equipment as that used for the pull rod, so there is no need for extra equipment such as temporary members, etc. No work is required and the cable can be easily installed.
Furthermore, by using the temporary lead-in wire, the cable terminal can be pulled in close to the bearing plate, so the length of the pull rod can also be shortened.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing one example of a device for carrying out this invention, FIG. 2 is a perspective view of a locking means, FIG. 3 is a perspective view showing another example of a locking means, and FIG. FIGS. 5 to 9 are sectional views showing the cable installation process, and FIGS. 10 and 11 are explanatory views of the cable installation process to explain the conventional method. 1... Cable, 2... Pull rod, 3... Bearing plate, 4... Guide member, 5... Jacket, 7, 8... Locking means, 6, 9, 60, 9
0... Wire for temporary lead-in.

Claims (1)

[Claims] 1. A pull rod having a thread on the outer periphery is screwed onto one terminal of the cable, and the pull rod is attached to the terminal with the other end of the cable fixed to a structure at the position where it is to be installed. In this method, the cable is passed through the bearing plate and the guide member, and tension is applied to the cable via the pull rod using jacks, and then the terminal fitting is locked to the bearing plate. Attach a nut to the temporary retraction bolt to be threaded with this bolt, and pull the pull rod into the guide member through the locking member and the temporary retraction bolt with the above jack, and then tighten the pull rod with the jack. A cable installation method characterized by applying tension to the cable through the cable. 2 Screw a pull rod with a thread on the outer periphery to one end of the cable, and with the other end of the cable fixed to the structure at the location where it is to be installed, attach the pull rod to the terminal tool bearing plate and guide member. In the method of locking the terminal fitting to the bearing plate after passing through the cable and applying tension to the cable via the pull rod with a jack, a temporary lead-in PC steel stranded wire with a wire diameter smaller than that of the pull rod is attached to the end of the pull rod. Connect the PC steel stranded wire with stoppers that protrude like flanges on the outer periphery at predetermined intervals, and pull the pull rod into the guide member via the locking member and the temporary pull-in PC steel stranded wire with the above-mentioned jack. A cable installation method characterized in that tension is then applied to the cable via a pull rod using a jack. 3 Screw a pull rod with a thread on the outer periphery to one end of the cable, and with the other end of the cable fixed to the structure at the location where it is to be installed, attach the pull rod to the terminal tool bearing plate and guide member. In the method of locking the terminal fitting to the bearing plate after passing through the cable and applying tension to the cable via the pull rod with a jack, a temporary lead-in wire having a wire diameter smaller than that of the pull rod is connected to the end of the pull rod, Attach a locking member to the temporary lead-in wire to mechanically connect it to the wire,
As the wire rod, a plurality of wire rods having different wire diameters are connected so as to become thinner from one side of the pull rod to the other side, and the jack is used to connect the pull rod to the guide member through the locking member and the temporary lead wire rod. A cable installation method characterized by pulling the cable into the cable and then applying tension to the cable via a pull rod using a jack.