JPH01219203A - Manufacture of oblique cable for diagonal cable bridge - Google Patents

Abstract

PURPOSE:To apply force equally to a plurality of tension members by cutting off tension members forming a set of oblique cables in a specific length, marking marks on the ends at a certain distance, truing up these marks and anchoring anchors respectively. CONSTITUTION:(A) Tension members 1 of PC steel stranded wires are cut off in a specific length. (B) Positioning marks M are marked on specific positions of the ends. (C) Each of tension members 1 is allowed to penetrate anchor heads 2a. (D) After that, cones 2b are set on each of tension members 1 passing through an anchor head 2a of the (c) tower side, and at that time the marks M on all tension members 12 are trued up horizontally to anchor in the vicinity of the anchor head 2a. (E) On the other hand, cones 2b are set on each of tension members 1 passing through an anchor head 2a of the beam (b) side as well. At that time, the marks are trued up horizontally by means of a well-known center-hole type single wire jack and the like. (F) Oblique cables (a) made through the above mentioned manufacturing process are erected between the actual beam (b) and tower (c). When Oblique cables (a) are erected to operate specific tensile force, distances among anchoring sections of a plurality of tension members 1 forming each set of obique cables are the same ones, so that the tensile force is applied equally to each of tension members 1.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing cables used in construction work of cable-stayed bridges.

<Prior Art> In construction of large span bridges, cable-stayed bridges are often used when it is difficult to support the bridge girder downwards or when the space under the girder is restricted. The main components of a cable-stayed bridge are girders, towers, and diagonal cables. Furthermore, when constructing cable-stayed bridges, stress management of the diagonal cables stretched between the girders and towers is particularly important. In general, diagonal cables are made of bundles of tensile materials such as PC steel wires or PC steel strands, and these bundles are coated with mantle tubes and subjected to rust-proofing treatment, and both ends of the bundles are connected to girders and It is fixed in the tower.

Problems to be Solved by the Present Invention> The conventional diagonal cable fixing technology described above has the following problems.

(B) When manufacturing a diagonal cable on site, the distance between the anchoring parts of each tensioning member varies depending on the twist and slack of each tensioning member. Therefore, the distance between the anchoring parts of each tensioning member is different. The larger the difference, the larger the difference in tension between the tension members after fixing, which makes it difficult to manage stress in the diagonal cable.

(b) It is difficult to understand from the outside that the distances between the anchoring parts of each tensile material that make up the diagonal cable are different, and as a result, excessive tension is applied to some of the tension members and they break. There is a risk of

(c) After installing the diagonal cable, it is conceivable to adjust the tension of each tensile member that makes up the diagonal cable, but this is difficult to implement due to the complexity and cost increase.

OBJECTS OF THE INVENTION The present invention has been made to solve the above problems, and provides a diagonal cable for cable-stayed bridges that can apply tension evenly to a plurality of tensile members constituting the diagonal cable. The purpose is to provide a manufacturing method.

Configuration of the present invention> An embodiment of the present invention will be described below with reference to the drawings.
A case where a wedge anchoring method, typified by the SL method, is adopted will be explained.

(a) Cutting the tensile material (Fig. 1) At a factory or the like, the tensile material 1, such as a stranded PC steel wire, wound around a drum or the like is cut to a predetermined length.

The total length L1 of the tensile material 1 to be cut is slightly longer than the distance between the anchoring parts at both ends when the diagonal cable a shown in FIG. 3 is installed between the tower C.

Marking (Fig. 1) Marks M for alignment are placed at fixed positions on both ends of each tensile material 1 cut to a certain length. The position where the marks M are written, that is, the distance L2 between the marks M on the tensile material 1 is:
When the installation of the diagonal cable a is completed, the fixing device to be fixed to the tensile member 1 is located at a visually visible position inside and outside, and marked with paint or tape.

Therefore, each tensile member 101 constituting one set of diagonal cable a
On one book, marks M are located at points separated by the same distance. Each tensile material 1 marked with a mark M is wound up into a coil and transported to the site.

(c) Pushing in the tensile material (Fig. 2) The fixing tool 2 used in the VSL construction method is shown in FIG.

2a is an anchor head having a large number of through holes, and screws are cut on the outer periphery of the anchor head. 2b is a split cone, which is a member that is inserted into each through hole of the anchor head 2a and directly grips the tensile member 1. 2C is a ring nut that is screwed onto the outer periphery of the anchor head 2a, and has a structure that abuts against the bearing pressure plate 2d to obtain a reaction force when introducing tension force.

To assemble the diagonal cable a, first, as shown in FIG. Place 4. In the figure, the anchor head 2a on the tower C side is placed on the left side of the drawing, and the anchor head 2a on the girder side is placed on the right side. and,
Each tensile member 1 with a mark M is directed from the anchor head 2a of the girder bm to the anchor head 2a of the tower C side, and is sequentially inserted using a known pushing machine 5. When inserting tensile material 1,
By sequentially inserting each anchor head 2a from the lower through hole to the upper side, the tension members 1 can be prevented from becoming entangled. or,
Every time one tensile member 1 is inserted, the vertical position of the opposing anchor head 2a is checked to prevent the tension member 1 from twisting.

(d) Fixation of one end of the tensile material (Fig. 4) Next, each tensile material 1 passing through the anchor head 2a on the tower C side
Set cone 2b on. At this time, marks M are made on all tension members 1 near the anchor head 2a on the tower C side.
Align them horizontally and fix them.

(E) Fixation of the other end of the tensile material (Fig. 4.5) On the other hand, girder bm
The same applies to each tensile member 1 penetrating the anchor head 2a (
Set cone 2b.

When fixing the anchor head 2a on the girder side, the marks M marked on each tensile member 1 are accurately aligned horizontally. In this embodiment, a case will be explained in which the deviation of the mark M is corrected using a known center hole type single wire jack.
Of course, other known correction devices can be used.

When the alignment of the marks M on the many tensile members 1 is completed, the cone 2b is set on each tensile member 1, and the production of the diagonal cable a is completed. The above work will be performed on the girder or near the site.

(d) Erection of diagonal cables In the above process, multiple sets of diagonal cables a with different overall lengths are manufactured,
It will be constructed between the actual girder and tower C. When the diagonal cable a is constructed and a predetermined tension is applied, the tension is borne equally by each tension member 1 because the distances between the anchoring parts of the plurality of tension members 1 constituting each set of the diagonal cable a are equal. It turns out.

Other Examples> In the above embodiment, a plurality of tensile members 1 are assembled in a manufacturing yard on the ground or on a girder, fixing devices 2 are fixed to both ends of the tensile members 1 to produce a diagonal cable a, and then a plurality of diagonal cables are assembled. We have explained the method of constructing all of A at once, but the mantle pipe 3 is constructed in advance, and then each tensile member 1 is inserted one by one into the mantle pipe 3, and the method is described on both ends of each tensile member 1. It can also be applied to a method in which the marks M are aligned and fixed.

Effects of the Present Invention> Since the present invention is as described above, the following effects can be expected.

(a) Marks were placed at the same distance on each tensile member making up the diagonal cable. Therefore, the distance between the anchoring parts of each tensile material can be standardized using the mark on each tensile material as a guide, and when tension is actually introduced, there is no difference in tension as in the past, and the load can be applied evenly. .

(b) Since the marks on each tensile member can be fixed as landmarks, the work of assembling the diagonal cable is simple and quick.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of the manufacturing process of a diagonal cable, and an explanatory diagram when marking the tensile material. Figure 2: An explanatory diagram when inserting the tensile material between the anchors. Figure 3: Cable-stayed bridge. Figure 4: Explanatory diagram when correcting the mark position Figure 5: Explanatory diagram when fixing the tensile material Figure 6: Partial sectional view of the fixing part Applicant Taisei Corporation - Agent Patent attorney Yamaguchi Sakuo Emi, ゛辷゛：lヱ- Figure 4 2b

Claims (1)

[Claims] (1) Cut a plurality of tension members constituting a set of diagonal cables to a predetermined length, mark each end of each tension member at a certain distance, and mark the above marks at both ends of each tension member. A method of manufacturing diagonal cables for cable-stayed bridges, in which the cables are aligned and each fixing device is fixed.