JPH048561B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a method for constructing tension members such as diagonal members in a cable-stayed bridge by tensioning a plurality of steel wires inside a sheath. .

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 a plurality of steel wires or steel wires such as steel stranded wires are inserted into a protective sheath made of synthetic resin, etc., and the steel wires, etc. are inserted into the sheath in advance and integrated. It was constructed using a construction method in which tension members were lifted onto scaffolding erected on site and directly connected at both ends to Tower T and Deck D, respectively. Almost the same method was used to erect tendons for other radio towers, etc.

Such conventional tendon construction methods have the following problems.

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

○B For long cable-stayed bridges, etc., the work scaffolding becomes extremely large, and it is necessary to spend time and construction costs just to erect this 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 tension materials to the site, they must be handled as heavy objects, and as the frame diameter of the reel increases, the material to be transported becomes bulky, making transport work extremely difficult, and in some cases transporting the material becomes impossible. Occasionally this occurred.

○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. must be set, and high measuring accuracy is required.

Purpose of the Invention The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a method for constructing tendons that allows easy tensioning and transportation of the tendons.

Structure of the Invention The tendon construction method according to the present invention involves inserting a sheath with anchor heads having a large number of index holes at both ends and attaching it to the fixing hole of a tower deck, and inserting a sheath of a predetermined length between these sheaths. Connect and bridge between the tower and deck,
Next, a large number of steel wires are sequentially fed and inserted into the sheath between the corresponding index holes of the anchor head, and then the steel wires are fixed under tension.

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

As the sheath 1, a cylindrical member made of synthetic resin with good weather resistance for rust prevention, such as steel wire, is used.
Other stainless steel pipes can 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 to form a predetermined length and used for construction.

Fixing holes 2, 2 are formed through the tower T and deck D, respectively, 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 in the same straight line.

The surfaces of the tower T and the deck D on the side opposite to the side on which the diagonal member L is installed are formed to intersect at right angles with the center lines of the fixing holes 2, 2, and form a seating surface. Fixing hole 2,
Inside 2 is a steel pipe 2 with a flange at the end.
1 and 21 are buried. 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. In particular, the socket 22 attached to the fixing hole 2 of the deck D has an adjusting nut 23 screwed onto its outer periphery, making it possible to adjust the position of the socket 22 in the direction of the center line of the fixing hole 2.

Anchor heads 3, 3 are fixed to the opposite sides 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, a3 corresponding to the number α of steel wires to be inserted through the surface thereof.
...aα is perforated. Each index hole a
1...aα is formed with appropriate isolation,
The upper end anchor head 3 to be attached to the tower T side and the lower end anchor head 3 to be attached to the deck D have index holes a1...aα corresponding to each other, and the center line of each index hole is the center of the fixing holes 2, 2. It is formed parallel to the line.

Short sheaths 1', 1' are connected to the sides of the sockets 22, 22 on which the diagonal member L is installed, respectively.
1' is positioned within each steel pipe 21, 21, and sheaths 1', 1' are attached to the anchor heads 3, 3 via sockets.

Further, one ends of the sheaths 1', 1' are made to protrude toward the side where the diagonal member L is installed. An outer periphery flange is formed at the lower end of the sheath 1' attached to the tower T side, and a cylindrical sealing material 24 having a flange is fitted to the outer periphery of the sheath 1' attached to the deck D side, so that the steel pipe is sealed. 21 is sealed.

A sheath 1 having a predetermined length made by connecting a plurality of sheaths each having a predetermined length is bridged between a tower T and a 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'. One end of this sheath 1 is suspended from the other end of a rope 25 whose one end is fixed above the tower T 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 positioned near the end of the sheath 1'.
The end of this sheath 1' on the deck D side is also temporarily attached to the other end of a rope whose one end is fixed to the deck D via a belt or the like.

A sheath outer cylinder tube 14 is fitted to the outer periphery of the end of the sheath 1 on the deck D side, and when connecting the sheath 1 end and the sheath 1' end, the sheath outer cylinder tube 14 is fitted to the outer periphery of both ends. and connect the two. The sheath outer tube 14 is fixed by heating both ends of the sheath outer tube 14 and welding them to the sheaths 1, 1'.

In the sheath 1 installed between the tower T and the deck D, a required number of steel wires 4 or a large number of steel wires such as steel stranded wires for taking care of the tension of the diagonal member L are prepared. In the embodiment, steel wires are prepared, and one end of the steel wire 4 is raised in sequence to near the fixing hole 2 on the tower T side of the lifting sheath 1, and then inserted through the index hole a1...aα of the upper end anchor head 3. and sheath 1
Insert it so that it goes down inside.

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.

First, when the steel wire 4 is inserted into the index hole a1 of the upper end anchor head 3, the steel wire 4 descends along the bottom of the inner peripheral surface of the sheath 1 and is inserted into the lower end anchor head 3.
When the steel wire 4 is tensioned, the entire length of the steel wire 4 is positioned at the top of the sheath 1, and the following steel wire 4 is inserted into the corresponding index hole a1.
There is no problem in descending along the bottom of the inner circumferential surface of the sheath 1, and there is no possibility that the steel wire 4 that has already been placed under tension and the following steel wire 4 will become entangled.

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 each steel wire 4 is inserted into the sheath 1 one by one and tensioned in this manner, all the steel wires 4 are tensioned simultaneously by a hydraulic jack or the like. A hydraulic jack or the like is used to tension the steel wire 4, and the end of the steel wire 4 is grasped and tensioned.

The tensioned steel wire 4 is fastened by wedges, compression grips, etc. on opposite sides of the upper and lower end anchor heads 3, 3, which are anchor plates. In the embodiment, it is fastened by a wedge 31 on the lower end anchor head 3 side, and by a compression grip 32 on the upper end anchor head 3 side.

By final tensioning of the steel wire 4, the deflection of the steel wire 4 is completely eliminated, and the deflection of the sheath 1 is also eliminated at the same time as the steel wire 4, and the final connection operation of the sheaths 1 and 1' is performed.

Grout is injected into the sheaths 1 and 1' to prevent rust of the steel wire 4. Mortar, synthetic resin, etc. can be considered as grout, but grout is
Since the resin is injected from below 1', the lightweight synthetic resin is easy to pump and does not cause cracks after curing, making it extremely suitable as a grout. A cylindrical grout injection cylinder is interposed between the opposite ends of the sheath 1' and the sheath 1 on the side of the deck D, and is fitted to both ends, and the grout is injected from the side of the grout injection cylinder. It is also possible to inject from above the sheath 1'.

The tendon construction method according to the present invention completes the erection of tendons such as diagonal members L through the above-mentioned work order.

Effects of the Invention Since the tendon construction method according to the present invention has the above-described configuration, the following effects can be obtained.

(a) First, only the lightweight sheaths are inserted into the fixing holes of the tower and deck, and then the steel wires are sent out one by one and inserted into the sheaths, so each task requires extreme efforts such as lifting heavy objects. It is no longer a difficult task; it becomes extremely easy.

(b) Since anchor heads having a large number of index holes are attached to both ends of the sheath, steel wires can be easily fed by selecting the corresponding index holes.

(c) The tension material has a sheath of a certain length, and each member can be transported to the site separately while the steel wire is wound on a reel, making transportation work extremely easy.

[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, and FIG. 6 is a plan view of the anchor head. T...tower, D...deck, L...diagonal material, 1...sheath, 2...fixing hole, 3...anchor head, 4...steel wire, 14...sheath outer tube, 21...steel pipe, 2
2...Socket, 23...Adjusting nut, 24...Sealing material, 25...Rope, 26...Annular belt, 31...Wedge, 32...Compression grip.

Claims (1)

[Claims] 1. Attach a sheath to which anchor heads with a large number of index holes are attached at both ends by inserting it into the fixing holes of the tower and deck, connect a sheath of a predetermined length between these sheaths, and bridge the sheath between the tower decks. Next, a large number of steel wires are sequentially fed and inserted into the sheath between corresponding index holes of the anchor head, and the tension members are then erected by tension-fixing the steel wires. Tensile material erection method.