JPH0411683B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a tension member for constructing a cable-stayed bridge, a radio tower, etc. by tensioning a plurality of steel wires, etc. inside a sheath. This relates to construction methods.

[Prior art] 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 built on the ground to suspend the deck D. . The tension material is made by inserting a plurality of steel wires or stranded steel wires through a protective sheath such as synthetic resin, and the steel wires are inserted into the sheath in advance to form the integrated tension material. It was erected using a construction method that involved lifting it onto scaffolding erected on site and directly connecting 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.

○A. The weight of the tension material, which consists of many steel wires inserted into the sheath, is extremely large, and the work to erect it is extremely difficult.

○B For long cable-stayed bridges, the work scaffolding was huge.

○C Tensile material made by inserting steel wires into a thick sheath of synthetic resin, etc., becomes bulky when wound on a reel, etc., making it extremely difficult to transport.

○D It is extremely difficult to insert multiple steel wires into a sheath without getting them entangled.

In order to solve the above problems, the applicant filed Japanese Patent Application No. 57-209000 (Japanese Unexamined Patent Publication No. 59-98974).
The method of constructing tendons disclosed in 2003-11 discloses that a fixed sheath to which an anchor head having an index hole is fixed at the end is installed facing the tower T, deck D, etc., and the construction sheath is spanned between the fixed sheaths.
Thereafter, the sheath is inserted between the corresponding index holes of the anchor head by descending from the upper anchor head into the sheath, and the steel wire tension member is installed within the sheath.

However, in this construction method, it is difficult to insert the steel wires that have descended from the upper fixed sheath and erection sheath into the lower fixed sheath and into the designated index holes of the anchor head at the lower end. It is.

In other words, in order to prevent the steel wires from becoming entangled with each other within the sheath, it is necessary to align the index holes of the upper and lower anchor heads accurately, insert the steel wires, and apply tension. It is extremely difficult to lower the anchor from above into the lower fixed sheath and insert it into any one of the many index holes in the anchor head at the lower end.

[Purpose of the invention]

This invention was made to solve the above-mentioned problems. First, only the sheath is installed, and then the steel wires are inserted into the index hole of the upper anchor head, and the steel wires are inserted through the sheath. It is an object of the present invention to provide a tendon construction method that allows a tension material to be inserted into a lower fixed sheath and into a predetermined index hole of an anchor head at the end of the sheath easily and accurately.

[Structure of the invention]

In this invention, two fixed sheaths each having an anchor head having an index hole at each end are installed facing each other with a certain distance between them, a construction sheath is spanned between the fixed sheaths, and then the anchor heads are connected to each other. A construction method in which steel wires are inserted between the index holes from the upper anchor head to the lower anchor head, and tension members are erected by tensioning the steel wires within the sheath, and the lower fixed sheath The lead cap at the end of the lead rope is inserted through the index hole of the anchor head into the lower fixed sheath with a space provided between the lower end of the sheath and the lower end of the erection sheath, and the steel wire is inserted from the upper anchor head. is fitted into the lead cap between the ends, and the steel wires fitted into the lead cap are guided into the index hole by the guide of the lead rope.

〔Example〕

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 sheaths 1 and 1', cylindrical members made of synthetic resin with good weather resistance are used to prevent rust of steel wires, but other materials such as stainless steel pipes can be used. It is extremely difficult to transport a long construction sheath 1, so a plurality of sheaths each having a certain length are connected together and used for construction.

[] 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.

A seat is formed on the opposite side of the tower T and deck D from the side where the diagonal member L is installed so as 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 side of each fixing hole 2, 2 opposite to 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 center line direction is possible.

Anchor heads 3, 3 are fixed to the sides of the sockets 22, 22 opposite to 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,
The center line of the corresponding index hole is the fixing hole 2, 2
The holes are parallel to the center line of the hole.

Short fixed sheaths 1', 1' are connected to the sides of the sockets 22, 22 where the diagonal member L is installed, respectively, and inserted into the respective steel pipes 21, 21, and the fixed sheaths 1', 1' are connected to the side where the diagonal member L is installed, respectively, and inserted into the respective steel pipes 21, 21. One end of the construction sheath 1 on the side of the deck D is fitted with a sheath outer cylinder tube 14,
When connecting the end of the construction sheath 1 and the end of the fixed sheath 1', the sheath outer tube 14 is fitted around the outer periphery of both ends to connect them. The sheath outer tube 14 is fixed by heating both ends of the sheath outer tube 14 to secure the sheaths 1 and 1'.
This is done by welding to the

A flange is formed on the outer periphery of the lower end of the fixed 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 fixed sheath 1' attached to the deck D side. steel pipe 2
The space between 1 and 1 is sealed.

[] Sheath Installation The construction sheath 1 connected as described above is installed between the tower T and the deck D. One end of the construction 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 fixed sheath 1'.
One end of this construction 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 construction sheath 1 is attached to the deck D by human power, etc.
The fixing hole 2 of the tower T is drawn near the fixing hole 2 corresponding to the fixing hole 2 of the tower T, and the fixing sheath 1' is positioned near the end of the fixing sheath 1'. The end of the fixed sheath 1' on the deck D side is also temporarily attached to the other end of the rope, one end of which is fixed to the deck D, via a belt or the like. Moreover, the construction sheath outer cylindrical tube 14 is fitted to the outer periphery of the deck-side end of the construction sheath 1.

First, the upper end of the construction sheath 1 on the tower T side is connected to the end of the fixed sheath 1' on the tower T side, and the construction sheath 1 is installed on the deck with the sheath outer tube 14 fitted to the lower end of the construction sheath 1. Fixed sheath 1' on D side
Place it close to the sheath and leave a gap between both sheaths.

In this way, the construction sheath 1 is constructed between the tower T and the deck D.

[] Sending out steel wires A required number of steel wires such as steel wires 4 or steel stranded wires to handle the tension of the diagonal member L are sent out into the sheath 1 installed between the tower T and the deck D. In the embodiment, a steel wire 4 is used, a reel 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 without being cut to a required length.

[V] Inserting the steel wire into the sheath The steel wire 4 fed from the reel is inserted between the sheaths 1' and 1'. First, the steel wire 4 is raised to the vicinity of the fixing hole 2 on the tower T side, and then inserted through the index holes a1...aα of the upper end anchor head 3 and lowered into the construction sheath 1.

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 construction sheath 1 descends along the bottom of the inner circumferential surface of the construction sheath 1 and is inserted into the corresponding index hole a1 of the lower end anchor head 3. When the steel wire 4 is tensed, the steel wire 4 moves to the top of the construction sheath 1. The entire length is positioned so that the following steel wire 4 can descend along the bottom of the inner peripheral surface of the sheath 1 without 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.

[] Insertion into the lower anchor head It is difficult to insert the steel wire into the index holes a1...aα of the anchor head 3 at the lower end of the fixed sheath 1' on the deck D side within the fixed sheath 1'. A member having a sheath-shaped lead cap 8 attached to the tip of a lead rope 81 as shown in FIG. 7 is used. That is, the lead rope 81 is inserted into the index holes a1...aα of the anchor head 3 on the deck D side and positioned in the fixed sheath 1' in advance, and the lead cap 8 is made to protrude above the fixed sheath 1'. The other end of 81 is made to protrude below the lower end anchor head 3.

Using the space between the lower end of the construction sheath 1 and the fixed sheath 1' on the deck side, the tip of the steel wire 4 is fitted into the lead cap 8, and the steel wire 4 is fed out again, while the lead rope 81 is pulled downward. , the steel wire 4 is securely inserted into the index hole a1 of each anchor head 3...
...Insert it into aα. After the steel wire 4 is inserted, both ends of the sheath outer tube 14 are welded to the sheaths 1 and 1'.

[] Tensioning the steel wire Tension the steel wire 4 inserted into the sheath 1 as described above. 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.

After all the steel wires 4 have been inserted, all the steel wires 4 are tensioned again to complete the erection of the tension members.

〔Effect of the invention〕

Since the present invention has the above-described configuration, the steel wire, etc. that has descended within the construction sheath is fitted into the lead cap at the tip of the lead rope using the gap between the ends of the construction sheath and the fixed sheath. It can be easily and reliably inserted into the index hole of the anchor head.

[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. Figure 4 is a longitudinal cross-sectional view of the fixing hole formed in the lead cap, Figure 5 is a cross-sectional view of the tendon, Figure 6 is a plan view of the anchor head, and Figure 7 is a sheath of the steel wire fitted to the lead cap. FIG. T...Tower, D...Deck, L...Diagonal material, 1
...Erection sheath, 1'... Fixed sheath, 2... Fixing hole, 3... Anchor head, 4... Steel wire, 8...
Lead cap, 81...lead rope.

Claims (1)

[Claims] 1. Two fixed sheaths each equipped with an anchor head having an index hole at the end are installed facing each other with a certain distance between them, a construction sheath is placed between the fixed sheaths, and then a construction sheath is placed between the corresponding index holes of the anchor head. A construction method in which steel wires are inserted from the upper anchor head to the lower anchor head, and tension members are erected by tensioning the steel wires within the sheath, and the lower fixed sheath and the lower end of the erecting sheath are Place the lead cap at the end of the lead rope, which has been inserted through the index hole of the anchor head, into the lower fixing sheath with a space in between, and then insert the steel wires that have been inserted from the upper anchor head into the above-mentioned space. 1. A method for constructing tendons, characterized in that the steel wires are fitted into the lead cap and guided by the lead rope into the index hole.