JP4847805B2 - Cable laying method - Google Patents

Description

  The present invention relates to a cable laying method for bundling tension members laid between fixing portions between a main girder and a main tower in an efficient work, for example, in a cable-stayed bridge cable.

  Conventionally, as shown in FIGS. 6 to 7A, the cable 21 in a cable-stayed bridge, a suspension bridge, or the like is guided by a guide wire or the like between the fixing portions 8 and 9 of the main girder 3 and the main tower 7, and is made of polyethylene. (PE) The coated strand 4 is inserted into the conical through hole 20 of the anchor head 18 and fixed with a wedge 19, and then the strand 4 is tensioned with a jack set on the fixing portion and tightened with the wedge 19. In addition, it is known that each of the plurality of strands 4 is applied to a uniform tension, and then all the plurality of strands 4 are gathered and fixed with a jack.

  In the cable 21, since the conical through-holes of the anchor head 18 are arranged concentrically with a required gap, if the strands laid in parallel with a gap are directly covered with a mantle protective tube, The diameter of the mantle protective tube 10a is increased. Then, the cable 21 may vibrate under the influence of wind and rain, leading to damage to the fixing tool. Therefore, there is a countermeasure for absorbing vibration by providing a damper such as a high damping rubber on the cable 21, and there is a method of connecting a clamp for bundling the cable 21 and the damper having one end fixed to the main girder.

  As a countermeasure against the vibration, there is a method of reducing the diameter of the cable 21 as much as possible in order to suppress the occurrence of the vibration of the cable 21 itself. Therefore, as shown in FIG. 7B, the diameter of the outer tube 10b is made as small as possible by bundling the plurality of strands 4 together with the clamp material 22.

For this purpose, conventionally, a plurality of strands constructed and tensioned in parallel with an appropriate interval between the fixing portions of the main tower and the main girder, and a plurality of strands, for example, hexagons by a pair of temporary clamps. A cable erection method is known that is shaped and bundled into a shape and then bundled with a permanent clamp to form a single cable (see Patent Document 1 and Patent Document 2).
Japanese Patent Laid-Open No. 08-27725 JP 2000-282409 A

  However, in the conventional cable laying method, a pair of temporary clamps are tightened in the radial direction of the cable with bolts on the strands that are laid in parallel with the fixing tube by inserting the strands through the protective tube, Or, it is a method of bundling by regulating the position with a stepped clamp, so if you reduce the diameter of the protective tube, in the work of pulling up the strand with the pilot cable and inserting it into the protective tube, it is already inserted as the number of inserted strands increases The strands become intertwined and get in the way, and it becomes difficult to gradually insert the strands. There is a demand for a reduction in work man-hours and a shortened work period by improving the work efficiency of inserting the strands into the protective tube. The cable laying method according to the present invention has been proposed in order to solve such a problem.

  The gist for solving the above-mentioned problems of the cable laying method according to the present invention to achieve the object is to insert a plurality of strands into a protective tube and to connect the ends thereof on the main tower side and the main girder side. When laying between both fixing portions, among the plurality of strands, a part of the upper strand when the strands are shaped and bundled is laid between the fixing portions to be tensioned, and the fixing portion At the free end opening of the sheath tube, a temporary shaping jig for temporarily fixing a part of the above-constructed upper strand at a position lower than the installation position of the strand is temporarily fixed, and then the remaining strands are fixed. Passing through the protective tube, laying between the fixing portions and tensioning them, and bundling the plurality of strands together with a permanent clamp member, and then attaching the temporary shaping jig to the free end opening of the sheath tube Is to remove from The

The temporary shaping jig is provided with a guide member for holding the strand inside the temporary shaping jig;
The guide member is detachable from the temporary shaping jig and can change the angle at which the strand is pressed inside;
Is included.

According to the cable laying method of the present invention, after a part of the upper side of the plurality of strands is laid between the fixing portions, the strand is shaped by a temporary shaping jig, and then the laid strand is In the cross section of the entire cable when bundled, the strands in the upper part thereof are in a dense state. After the strands are completely installed between the fixing portions, when the strands are bundled with the permanent clamp member, the upper part of the entire cable is in a compacted state. The work of pinching and bundling becomes easier and the work efficiency is improved.
Further, the temporary shaping jig is provided with a guide member, and when the lower strand of the entire cable is installed between the fixing portions, the temporary shaping jig is regulated so as to be pressed inside the jig. Therefore, when the strands are bundled by the two-piece permanent clamp, the strands are converged by the guide member, and the operation of bundling the strands becomes easy.
Further, if the guide member can be attached to and detached from the temporary shaping jig and the angle at which the strand is pressed inward is variable, the length of the guide member is changed according to the number of strands to be installed. Or the strand guide angle can be changed as appropriate, which makes the jig more convenient.

  As shown in FIG. 1, the cable laying method according to the present invention is as follows. First, in the sheath tube 1 of the fixing portion on the main girder side and the main tower side of the cable-stayed bridge, the flange of the free end opening 1a is provided. A temporary shaping jig 2 to be fixed to 1b with bolts and nuts is formed.

  The temporary shaping jig 2 has a shape corresponding to a half of the shape of the flange 1b of the sheath tube 1 which is the cylindrical body, a metal substrate 2a having a required plate thickness, and welding on both sides at a position below the substrate 2a. The metal screw base blocks 2b and 2d fixed in the above, the metal screw base 2c fixed to the upper part by welding or the like, and the screw bases 2b and 2d and the screw base 2c are screwed so as to be able to advance and retreat. Screw rods 2e, 2g, 2f to be combined, a semi-hexagonal shaping block 2h pressed by the screw rods 2e, 2g, 2f, and a pair of guide members 2i fixed to the shaping block 2h in eight shapes And is composed of.

  The board 2a is detachably fixed to the flange 1b by being inserted into the mounting hole with bolts and nuts. The contact plate 2j at the tip of the screw rods 2e, 2g, and 2f is a disc body that presses the shaping block 2h.

  The shaping block 2h aligns the strands and has a half shape of a hexagon. This width is arbitrary, but the width is set so as not to damage the polyethylene (PE) coating of the strand because the upper strand row is pressed. Further, the guide member 2i is a metal bar having an octagonal shape at the bottom, and is fixed by means such as welding along the inclined side of the semi-hexagon. The length of the guide member 2i is set so as to reach the sheath tube 1 almost.

  Next, a cable laying method according to the present invention that is constructed using the temporary shaping jig 2 will be described. As shown in FIG. 2, in the cable-stayed bridge, the sheath tube 1 is provided at the fixing portion on the main girder 3 side, and the anchor head 3a is fixed by the fixing nut 3b. A flange 1b is provided at the end of the free end opening 1a exposed on the main beam 3 and facing the main tower.

  From the main girder 3 side, in order to insert the PE-coated strand 4 through the PE protective tube 5 and send it to the main tower side, the strand 4 drawn out from the drum or the like is pushed up by, for example, a pushing machine 6, If the distance is long, the pilot cable inserted and lowered in advance through the protective tube 5 is connected to the end of the strand 4 and pulled up by the pilot cable. Then, the ends of the strands are processed into the fixing portion of the fixing sheath tube on the main tower side and the fixing portion of the sheath tube 1 on the main girder side, and are fastened to the conical hole of the anchor head with a wedge, and the first strand 4 Is installed. After the strand 4 is installed, it is tensioned with a jack, but the strand 4 hangs down by the weight of the protective tube 5.

  As shown in FIG. 3, among the plurality of strands 4, for example, in a case where the strands 4 are shaped into a hexagonal shape and bundled, the upper part of the strands 4 is laid between the fixing portions and is tensioned. . For example, when the number of strands 4 is 19 in total, there are three upper rows, or in the case of 24 strands, there are four upper rows.

  Next, as shown in FIG. 4, a part of the upper strands 4, 4,... Laid on the upper end of the sheath pipe 1 of the fixing portion on the main girder 3 side or the main tower side, as shown in FIG. A temporary shaping jig 2 that is temporarily fixed at a position lower than the installation position of the strands 4, 4. For this, the base plate 2a having the screw base blocks 2b, 2c, 2d is inserted into the flange 1b, and the bolt / net is inserted into the bolt hole and fastened.

  Then, the shaping block 2h is placed on the upper part of the strand 4 from above, and the screw rods 2e, 2f, and 2g are tightened so that the strand 4 is positioned lower than the installation position. Positioning is performed with the contact plate 2j. As a result, the upper strands 4, 4,... Are aligned and pressed by the shaping block 2 h of the temporary shaping jig 2 to be dense.

  Since the upper part of the strands 4, 4... Are tensioned between the two fixing portions, the upper strands 4 and 4... Are concentrated in the upper part of the protective tube 5, and a space 5a below the strand 4 in the protective tube 5 is secured widely. The Thereafter, as shown in FIG. 5, the remaining strand 4 is inserted into the space 5 a of the protective tube 5, and is stretched between the fixing portions to be tensioned.

  The remaining strands 4 to be inserted into the protective tube 5 are inserted after the upper part of the strands 4, 4... Are densely arranged on the upper portion of the protective tube 5, so that they are inserted in order from the upper side. For example, the subsequent strands 4 gather one after the other on the upper side of the protective tube 5 and are densely packed, and the subsequent strand 4 can be easily inserted. And since the strand 4 below from the center part of the protective tube 5 is not restrained by the molding block 2h of the temporary shaping jig 2, it is freely scattered in the installation position inside the guide members 2i and 2i.

  Thereafter, the plurality of strands 4 are bundled together with a permanent clamp member (not shown). This permanent clamp is, for example, a clamp material in a state in which a hexagonal shape is divided into two vertically. Since the upper half of the entire strand 4 is densely packed in a hexagonal half shape by the shaping block 2h, the upper clamp member can be easily placed on the strand 4 and easily installed. Then, when the lower half clamp material pushes up the scattered strands 4 from the bottom to the top, the lower strands 4 are gathered by the guide members 2i and 2i so that the lower clamp material can be easily combined with the upper clamp material. Can be combined.

  The plurality of strands 4 are combined into one cable by the permanent clamp member. Thereafter, the temporary shaping jig 2 is removed from the free end opening 1 a of the sheath tube 1.

  Another embodiment of the cable laying method according to the present invention is to make the guide members 2i, 2i detachable from the temporary shaping jig 2 in the temporary shaping jig 2, using bolts or clamps. It is intended to be removable. This is convenient when the guide member 2i is replaced with one having a different length or thickness. Further, if the angle at which the strand 4 of the guide member 2i is pressed inward is variable, the angle of the figure eight can be arbitrarily expanded depending on the condition of the strand 4 being scattered. It is convenient. In order to do this, for example, a plurality of types of mounting holes for each angle are prepared in advance on the mounting surface of the shaping block 2h, and the guide member 2i is fixed with a clip with screws, bolts, or the like. This is possible.

It is a perspective view which shows the use condition of the temporary shaping jig | tool 2 in the construction method of the cable-stayed cable which concerns on this invention. It is explanatory drawing explaining the construction method of the cable-stayed cable of the same invention. It is explanatory drawing explaining the construction method of the cable-stayed cable of the same invention. It is explanatory drawing of the state which attached the temporary shaping jig | tool 2 to the sheath pipe | tube 1 by the construction method of the cable-stayed cable of this invention. It is explanatory drawing of the state which installed all the strands 4 by the construction method of the cable-stretched cable of the same invention. It is explanatory drawing which shows the construction method of the diagonal cable which concerns on a prior art example. They are a sectional view (A) showing how the strand 4 is fixed to the anchor head 18 and a perspective view (B) showing how the strand 4 is bundled with the clamp material 22.

Explanation of symbols

1 Cable-laying cable installation method, 1a Free end opening,
1b flange,
2 Temporary shaping jig, 2a substrate,
2b, 2c, 2d screw base block,
2e, 2f, 2g screw rod,
2h Block for shaping,
2i guide member,
2j
3 main girder, 3a anchor head,
3b fixing nut,
4 strands,
5 protection tube, 5a space,
6 Pushing machine.

Claims (3)

When inserting a plurality of strands through a protective tube and laying the ends between the fixing portions on the main tower side and the main girder side,
Among the plurality of strands, the upper part of the strand when shaped and bundled is stretched between the fixing portions and is tensioned.
Temporarily fixing a temporary shaping jig for temporarily fixing the part of the laid upper strand at a position lower than the erected position of the strand to the free end opening of the sheath tube of the fixing unit,
After that, the remaining strand is inserted through the protective tube and is laid between the fixing parts and is tensioned.
The plurality of strands are bundled together with a permanent clamp member,
Then, removing the temporary shaping jig from the free end opening of the sheath tube,
A cable-laying method characterized by the above. The temporary shaping jig is provided with a guide member that holds the strand inside the temporary shaping jig,
2. A cable laying method according to claim 1, wherein the cable is laid. The guide member is detachable from the temporary shaping jig and can change the angle at which the strand is pressed inward.
The temporary installation method of the cable-stayed cable of Claim 2 characterized by these.

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