JPH048562B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to the construction of tension members such as stay members in cable-stayed bridges, radio towers, etc. by tensioning a plurality of steel wires within a sheath. It is related to construction methods.

BACKGROUND ART Conventionally, as shown in FIG. 1, a cable-stayed bridge has been developed in which a plurality of diagonal members L, which are tension members, are installed between a tower T and a deck D constructed on the ground to suspend the deck D. The tension material used is one in which multiple steel wires, stranded steel wires, etc. are inserted into a protective sheath such as synthetic resin. It was erected using a construction method in which it was lifted onto scaffolding set up in the ground and directly connected at both ends to Tower T and Deck D, respectively. Almost the same construction method is also used to erect tendons for other wireless towers, etc.

Such conventional tendon construction methods have the following problems.

○B. The weight per unit length of tendons with multiple steel wires, etc. inserted into the sheath becomes extremely large, and the diameter also becomes thick. Also, in long cable-stayed bridges, etc., the longest length of the tendons is It was several hundred meters long, and the work of lifting this tension material onto the scaffolding and connecting it between Tower T and Deck D was extremely difficult.

(b) The work scaffolding used to span the tendons on long cable-stayed bridges is extremely large, and it takes time and construction costs just to assemble the scaffolding.

○C Hard and thick tubes made of synthetic resin are used as sheaths, but tension materials with steel wires, etc. inserted inside these sheaths are manufactured in factories and wound around the winding frame of reels. When transporting the tension materials to the site, the tension materials must be treated as heavy objects, and the diameter of the frame of the reel becomes large, making transport work extremely difficult, and sometimes transporting the tension materials becomes impossible.

○D As mentioned above, if it is not possible to transport the tendons, it will be necessary to construct a factory on-site and assemble the tendons on-site.

○ E. It is extremely difficult to insert and tension multiple steel wires into the sheath without tangling them, both in factories and on-site. Furthermore, the length of the tension material must be adjusted depending on the installation location. Each must be set, and high calculation accuracy is required.

In order to improve these shortcomings, a patent application was filed in 1983.
The tendon construction method disclosed by the present applicant in No. 209000 (Japanese Unexamined Patent Publication No. 59-98974) is to span a sheath with anchor heads having index holes at both ends, and then insert the corresponding index holes in the anchor heads. A tension member is constructed by inserting a steel wire or the like between the sheaths and tensioning the steel wire or the like within the sheath.

According to this construction method, the steel wires are inserted after the sheath is stretched, making it easier to erect the tendons.
This method eliminates the need for huge scaffolding, eliminates the need to construct a factory on site, and facilitates the insertion of steel wires, all of the above drawbacks being eliminated.

However, when the end of the sheath is located at a high location, it is extremely difficult to feed the steel wire close to the anchor head attached to the end of the sheath. In other words, in cable-stayed bridges, etc., it is necessary to erect scaffolding along the tower and lift the steel wire wound on a reel to a high place, which is extremely troublesome and difficult to work at high places. It poses a danger.

Purpose of the Invention This invention was made to improve the above-mentioned drawbacks, and when inserting a steel wire, etc. into a sheath that has been bridged, it is possible to very easily feed out the steel wire, etc., thereby reducing the danger. The purpose of the present invention is to provide a tendon construction method that allows for the construction of tendons.

Composition of the Invention In the tendon construction method according to the present invention, when a steel wire or the like is inserted into a sheath with anchor heads attached to both ends, a guide pipe with one end close to one of the anchor heads is installed, and Feed the steel wire etc. into the guide pipe from the other end,
The above object is achieved by passing the steel wire or the like into the sheath through the index hole of the anchor head.

Embodiment The present invention will be described in detail below based on an embodiment of a cable-stayed bridge shown in the drawings.

[] Sheath connection As the sheath 1, a cylindrical member made of synthetic resin with good weather resistance is used to prevent rust of steel wire, etc.
Other materials such as stainless steel pipes can also be used. It is extremely difficult to transport a long sheath 1, so a plurality of sheaths 1 having a certain length are connected together and used for construction.

That is, an electric heating plate is interposed between the adjacent sheaths 1, 1 to heat both end surfaces of the sheaths 1, 1,
After heating, both end surfaces are pressed together and welded to connect. A spiral spacer wire 11 is attached to the inner peripheral surface of the sheath 1.

It is also possible to attach a spacer wire 11 to the inner peripheral surface of the sheath 1 over the entire length after the sheath 1 is connected. Further, when a stainless steel pipe is used as the sheath 1, it is possible to connect them by welding.

[] Formation of Fixing Holes in Tower and Deck Fixing holes 2, 2 are formed through the tower T and deck D in correspondence with each other. The fixing holes 2, 2 are formed at appropriate intervals in the vertical direction of the tower T and in the longitudinal direction of the deck D by the number of diagonal members L to be installed. The fixing holes 2, 2 formed in correspondence with the tower T and the deck D are bored so that their respective center lines are on the same straight line.

The surfaces of the tower T and the deck D opposite to the side on which the diagonal member L is installed are formed to intersect the center line of the fixing holes 2, 2 at right angles. Steel pipes 21, 21 having flanges at their ends are buried in the fixing holes 2, 2. A cylindrical socket 22, 22 is attached to the opposite side of each fixing hole 2, 2 from the side on which the diagonal member L is installed. Especially the fixing hole 2 of Detsuki D.
An adjustment nut 23 is screwed onto the outer periphery of the socket 22 attached to the socket 22, and the fixing hole 2 of the socket 22
Position adjustment in the direction of the center line is possible.

Anchor heads 3, 3 are fixed to the opposite side of the sockets 22, 22 from the side on which the diagonal member L is installed. The anchor heads 3, 3 are disk-shaped as shown in FIG. 6, and have index holes a1, a2, a corresponding to the number α of steel wires to be inserted through the surface thereof.
3...aα is perforated. Each of the index holes a1...aα is formed at appropriate intervals, and an upper end anchor head 3 is attached to the tower T side, and a lower end anchor head 3 is attached to the deck D.
The index holes a1, .

Short sheaths 1', 1' are connected to the sides of the sockets 22, 22 on which the diagonal member L is installed, respectively, and are positioned within the respective steel pipes 21, 21, and the diagonal member L
One end of the sheaths 1', 1' is made to protrude toward the side where the sheaths 1', 1' are installed. Sheath 1' installed on the tower T side
A flange is formed on the outer periphery of the lower end of the sheath 1', and a cylindrical sealing material 24 having a flange is fitted on the outer periphery of the sheath 1' attached to the deck D side, thereby sealing the gap between the sheath 1' and the steel pipe 21. There is.

[] Sheath Installation The sheath 1 connected as described above is installed between the tower T and the deck D. One end of the sheath 1 is lifted up by a crane erected adjacent to the tower T and pulled to the vicinity of the fixing hole 2 of the tower T, and is positioned near the end of the sheath 1'. This sheath 1
A rope 2 with one end fixed above the tower T
It is suspended from the other end of 5 via a steel annular belt 26 or the like.

The other end of the sheath 1 is manually drawn to the vicinity of the fixing hole 2 corresponding to the fixing hole 2 of the tower T of the deck D, and is positioned near the end of the sheath 1' that has been inserted into the fixing hole 2 in advance. urge

The end of this sheath 1 on the deck D side is also temporarily attached to the other end of a rope with one end fixed to the deck D via a belt or the like.

First, the end of sheath 1 is connected to the end of sheath 1'.

The sheath outer cylinder 14 is fitted to the outer periphery of the end of the sheath 1 on the side of the deck D, and then the other end of the sheath 1 and the end of the sheath 1' inserted into the fixing hole on the side of the deck D are connected at both ends. The sheath is constructed between the tower T and the deck D by fitting the sheath outer cylinder tube 14 to the outer periphery and connecting the two. The sheath outer tube 14 is fixed to the sheath outer tube 1.
This is done by heating both ends of 4 and welding them to the sheaths 1 and 1'.

[] Sending out the steel wire (Fig. 7) As mentioned above, the required number of steel wires 4 or steel stranded wires, etc., to take care of the tension of the diagonal member L are sent out into the sheath 1 installed between the tower T and the deck D. do. In the embodiment, a steel wire 4 is used, a reel 41 wound with the steel wire 4 is placed on a deck D, etc., and the steel wire 4 is continuously fed out from the reel 41 without being cut to a required length.

The steel wire 4 is force-fed by a pusher 43 having rollers 42 that are rotated opposite each other by a prime mover, and is raised along the tower T through a hard guide pipe 44 such as a steel pipe that extends above the tower T. A bendable flexible guide pipe 45 made of synthetic resin or the like is connected to the upper end of the guide pipe 44, and the tip of the flexible guide pipe 45 is positioned near the anchor head 3 attached to the fixing hole 2 of the tower T. The flexible guide pipe 45 is bendable and the anchor head 3
The steel wire 4 can be sent out to each index hole a1...aα without any trouble.

Reel 41, pusher 43, guide pipe 4
4 is not limited to one each, but it is also possible to prepare a plurality of each and sequentially send them to different index holes a1...aα.

[] Inserting the steel wire into the sheath The steel wire 4 fed out from the reel 41 is inserted into the sheath 1', 1. As mentioned above, the steel wire 4 has been raised to the vicinity of the fixing hole 2 on the tower T side of the sheath 1, so it is inserted through the index hole a1...aα of the upper end anchor head 3 and lowered into the sheath 1. and then insert it.

The index holes a1, . In the embodiment, the index holes a1, . . . aα shown in FIG.
a3..., and finally insert it into the index hole aα located at the bottom.

Index hole a1 of upper end anchor head 3
The steel wire 4 inserted into the sheath 1 descends along the bottom of the inner peripheral surface of the sheath 1 and is inserted into the corresponding index hole a1 of the lower end anchor head 3, and by tensioning this, the steel wire 4 moves to the top inside the sheath 1. The entire length is positioned so that the following steel wire 4 can descend along the bottom of the inner circumferential surface of the sheath 1 without causing any hindrance, and the steel wire 4 that has already been placed under tension is entangled with the following steel wire 4. Nothing seems to fit.

After the steel wire 4 that has been inserted first is tensed as described above, the steel wire 4 is lowered in order and inserted into the sheath 1.

After the steel wires 4 are inserted through all the index holes a1...aα, all the steel wires 4 are tensioned using a high-power hydraulic jack to complete the erection of the diagonal member L.

Effects of the Invention The tendon erection method according to the present invention has the above-described configuration, and uses a guide pipe to send out the steel wire, etc. to reach near the anchor head, and sequentially insert the steel wire, etc. into each index hole. This makes it extremely easy to send out steel wires, etc., without the need to install large-scale work scaffolding, and reduces work hazards.

[Brief explanation of drawings]

Fig. 1 is a front view of an embodiment of a cable-stayed bridge, Fig. 2 is an explanatory diagram of a state in which tension members are strung across the tower and deck, Fig. 3 is a longitudinal cross-sectional view of the fixing hole formed in the tower, and Fig. FIG. 4 is a longitudinal sectional view of the fixing hole formed in the deck, FIG. 5 is a cross-sectional view of the tendon, FIG. 6 is a plan view of the anchor head, and FIG. 7 is an explanatory view of the steel wire being fed out. T...tower, D...deck, L...diagonal member, 1...sheath, 2...fixing hole, 3...anchor head, 4...steel wire, 5...pilot cap, 6...truck, 8...lead cap, 9...index Spacer, 11
...Spacer wire, 44...Guide pipe.

Claims (1)

[Scope of Claims] 1. A sheath to which anchor heads having index holes at both upper and lower ends are attached is hung diagonally, and then steel wires are inserted between the corresponding index holes of the anchor heads, and the sheath is inserted into the sheath. In the tendon construction method in which tendons are erected by tensioning steel wires at A tendon construction method characterized by feeding the steel wires from the anchor head, inserting the steel wires into the sheath through the upper index hole of the anchor head, and then inserting the steel wires into the lower index hole.