JP3148464B2 - Suspension scaffold for cable erection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension scaffold (catwalk) used for erection of a suspension bridge cable.
In particular, it relates to a suspension scaffold that does not require a storm rope in a long suspension bridge.

[0002]

2. Description of the Related Art Conventionally, cable erection of a long suspension bridge is shown in FIG.
As shown by a dotted line 0, a suspended scaffold (catwalk) 5 has been used in which a floor set is stiffened by a storm rope 6 via a hanger rope 7. The hanging scaffold 5 needs to have a function as a work passage for installing devices for laying cables and for workers to lay cables. Therefore, it is desirable that the torsional deformation of the floor set when the cable is erected and the deformation in the direction perpendicular to the bridge axis due to the wind be small. As shown in FIG. 11, the suspension scaffold using a storm rope is suspended by a storm rope 6 stretched using a fixing hardware attached to a base of a tower via a hanger rope 7 connected to a floor set. 5 is pulled downward and stiffened. By providing the storm rope 6, the suspension scaffold 5
The torsional deformation of the suspended scaffolding that occurs when various erection devices are arranged on the upper side or when cable erection work is performed is suppressed, and stable cable erection work is possible. In addition, the swinging and deformation of the suspended scaffold due to wind during cable erection can be suppressed, and the relative displacement between the floor assembly and the cable can be reduced, whereby the cable can be erected stably without contacting the floor assembly. .

[0003]

However, a hanging scaffold using a storm rope requires a great deal of labor for mounting the storm rope and requires a long construction period for mounting. Furthermore, when the stiffening girder is erected following the cable erection, it is necessary to remove the storm rope before the stiffening girder is erected, because the setting position of the storm rope interferes with the stiffening girder installation. There were issues such as a longer construction period for removal. If a hanging scaffold without a storm rope is used, the floor set is significantly unstable torsionally deformed by cable pull-out when the cable is laid, which may cause troubles such as disconnection of the pull-out rope when the cable is laid. Further, there is a problem that the deformation due to the wind becomes large, which hinders the cable shape adjusting work (sag adjustment) performed by free-hanging the cable between the two towers. The present invention has been made in view of the above circumstances, and has as its object to provide a suspension scaffold that solves the conventional problems without impairing the function of the suspension scaffold with a storm rope.

[0004]

To achieve the above object, the gist of the present invention is as follows. That is, (1) a large number of catwalk ropes installed in parallel between towers or between towers and abutments are held by cross beams arranged at appropriate intervals in the bridge axis direction, and a floor set is fixed on the upper part. In a suspension scaffold for cable erection of a suspension bridge, a reinforcement rope is laid in parallel with the catwalk rope at intervals on both sides of a floor group of the suspension scaffold, and the reinforcement rope is fixed to an abutment or a tower portion. It is a hanging scaffold for cable erection, characterized in that it is fixed to the end of the cross beam projected on both sides of the hanging scaffold,
(2) The cable-hanging suspension according to the preceding paragraph, wherein the diagonal floor sets of two hanging scaffolds installed between the left and right towers or between the tower and the abutment are connected by stay ropes to prevent deformation due to wind. The suspension scaffold for cable erection according to the preceding clause, wherein a lightweight and high-strength fiber rope is used for the scaffold and (3) the diagonal stay rope.

According to the present invention, a reinforcing rope is stretched on both sides of a floor set in place of a storm rope, that is, a cross beam attached to a floor set is extended at an interval of about a conventional hanger mounting position to suspend a scaffold. And is fixed to the reinforcing ropes on both sides to improve the resistance of the floor set against twisting. If a rope with the same diameter as that of the catwalk floor group is used for the reinforcing rope that extends on both sides of the floor group, it can be laid in the same procedure as the catwalk rope, and special structures and erection equipment Is also unnecessary, and the time required for erection only slightly increases. By taking such measures, even a suspended scaffold without a storm rope can have a function for torsional resistance equal to or greater than that of a suspended scaffold with a storm rope. Further, since the storm rope is not used, the construction period for installing and removing the storm rope can be shortened.

[0006] The deformation and sway of the floor set in the direction perpendicular to the bridge axis due to the wind is to improve the deformation resistance by connecting the two floor sets with diagonal stay ropes. Usually, in a large suspension bridge, two floor sets are connected by a cross bridge 9 as shown in FIG. An oblique stay rope 8 is stretched between the cross bridges, and deformation due to wind load can be suppressed by the truss effect. The stay ropes 8 may be arranged between all the cross bridges 9, but since the deformation resistance of the floor set due to the wind is greatest near the tower 10, it is sufficient to attach the stay rope only between the cross bridges near the tower 10. The effect is obtained. The oblique stay ropes 8 may be attached to the cross bridge 9 on one side and the tower wall or the like on the other side. For fixing, members such as an eye plate U-shaped metal piece or the like are sufficient. No erection equipment is required.

A normal steel rope may be used for the slanting stay rope 8, but if a high-strength and lightweight rope having a tensile strength and an elastic coefficient equal to or higher than that of the steel rope is used, for example, a carbon fiber rope or the like is used. It is possible to suppress deformation efficiently. Since the specific gravity of the carbon fiber rope is about 1/5 of that of the steel rope, the tension due to its own weight at the time of stretching is about 1/5 of that of the steel rope. Since the initial tension is small, the floor structure formed along the cable erection shape The catenary shape is not disturbed and the workability is not reduced, and the erection equipment can be simplified. In addition, since the carbon fiber rope can reduce the slack (sag) of the rope with a small tension, it is hardly affected by the sag when a wind load is applied, and contributes to the suppression of the deformation, thereby improving the efficiency.

[0008] As described above, by extending the oblique stay rope between the cross bridges, even in the case of the deformation caused by the wind, the suspension scaffold without the storm rope has a function of the same deformation resistance as the suspension scaffold with the storm rope. Can be.

[0009]

[Function] A reinforcing rope is stretched over a cross beam protruding on both sides of the floor set, and the reinforcing rope suppresses torsional deformation of the floor set, and furthermore, a double hanging scaffold installed on the left and right in the bridge axis direction. The floor set is connected with diagonal stay ropes using lightweight and high-strength fiber ropes, and the truss effect of this rope suppresses the deformation of the floor set due to the wind. Demonstrate the same function as a scaffold.

[0010]

Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of the present invention for a part near a tower. Abutment 16 (see FIG. 2) and tower 10 or tower 1
The reinforcing ropes 2 are stretched at both sides of the floor set 1 of the cable erection hanging scaffold 5 erected between the tower 0 and the tower 10, and the cross beams 3 attached to the floor set are extended to protrude from the end of the floor set. FIG. 2 shows a suspension scaffold 5 without a storm rope fixed to reinforcing ropes 2 on both sides. FIG. 10 shows the side surface of the entire length of the suspended scaffold, and the conventional storm rope 6 and hanger rope 7 are indicated by dotted lines.

The hanging scaffold 5 is composed of an abutment 16 and a tower (side span side) 1.
0, the tower 10 is laid between the towers 10 (center span) in a shape substantially similar to that of the cable. Conventionally, a hanger rope 7 is hung from the floor set 1 of the hanging scaffold 5 at predetermined intervals in the bridge axis direction, and the lower end thereof is attached to a storm rope 6 which is stretched and fixed at an abutment upper portion or an intermediate height of a tower. .
In the present invention, the hanger rope 7 and the storm rope 6
Since (the dotted line in FIG. 11) is not provided, the lower part of the hanging scaffold 5 becomes a wide space.

FIG. 2 is a plan view showing an embodiment according to the second aspect of the present invention.
By disposing the diagonal stay ropes 8 in 5, the deformation of the floor set due to the amount of wind load can be suppressed. In the figure, reference numeral 9 denotes a cross bridge connecting left and right suspended scaffolds.

FIGS. 3 and 4 show details of mounting the slanting stay rope 8. The diagonal stay rope 8 has two ropes arranged in a cross shape, and one end is fixed to a member of the cross bridge 9,
The other end is attached and fixed to a fixed piece provided on the tower wall 10.
When arranging between the cross bridges, the rope ends are fixed to the cross bridge members, and are arranged in a cross shape.

FIGS. 5 and 6 show details of the suspension scaffold of the present invention. For example, when the center span is about 1000 m,
The outer diameter of the catwalk rope 4 for forming
It is composed of six pieces of about mm. Reinforcing ropes 2 of the same diameter are installed at a position separated by about 1500 mm from both sides of the floor set 1. The cross beam 3 holds the catwalk rope 4 and fixes a device for drawing out and erection of the cable, and is attached at a rate of about 40 to 50 m in the bridge axis direction at one place. In the present invention, the cross beam 3 is extended outside the width of the floor set 1 and attached to the reinforcing ropes 2 on both sides of the floor set 1 to increase the resistance to twisting. still,
The effect of preventing torsion increases when the distance between both ends of the floor set 1 and the reinforcing rope 2 is made as large as possible. However, from the viewpoint of the rigidity of the cross beam 3, it is practically set to about 1 to 2 m. In the figure, 11 is a main cable, 12 is a wire mesh stretched on a floor set, 13 is a square pipe to be installed in the floor set axial direction, 14 is wood, and 15 is a handrail. Fig. 7 has a storm rope, no storm rope,
4 shows a relationship between torsional deformation of a suspended scaffold (inclination of a floor group) and a load in the case of the present invention. The torsional deformation of the suspension scaffold of the present invention is such that, for example, even when a load of 30 kg / m at the time of pulling out a cable is applied to the side end of the floor assembly, the inclination of the floor is about 3 degrees, which is smaller than 4 degrees with a storm rope. It shows higher performance. On the other hand, when there is no storm rope, the inclination of the floor set is as large as 8 degrees, which hinders work on the suspended scaffold.

FIG. 8 shows the deformation of the suspended scaffold in the direction perpendicular to the bridge axis due to the wind in the case of the present invention having a storm rope, no storm rope, and an oblique stay rope. The diagonal stay rope is an example in which a 180-meter wire rope of 30 mm is used only between the tower and the crossbridge. At a wind speed of about 12 m / s, which is a workable wind speed range, the deformation at the center of the span of the suspended scaffold according to the present invention is slightly larger than that of the suspended scaffold with the storm rope,
Compared to a suspended scaffold without a storm rope, the amount of deformation is about 60%, and stable cable erection work can be performed even when the wind load acts.

FIG. 9 shows a change in rope tension up to a wind speed of 12 m / s, which is a workable wind speed range, when a lightweight and high-strength carbon fiber rope and a steel rope 180 m are used as the slanting stay rope. . (Sag amount 5m). Steel rope has a heavy weight, so the initial tension at the time of stretching is 10t
However, the carbon fiber rope has a weight per unit volume of about 1/5 that of a steel rope and is lighter, so the initial tension due to its own weight when it is stretched is only 2t. The rate of increase in tension is low. in this way,
If a carbon fiber rope is used, it can be attached manually using simple erection equipment. The rope tension at a wind speed of 12 m / s is about 14 t when using a carbon fiber rope, while 42 t when using a steel rope.
Assuming that the safety factor against breakage is 3.0, the design load of the anchoring structure of the carbon fiber rope is only 42t, while the design load of the steel rope is as large as 126t, and the anchoring structure is also large. As described above, it is more effective to use a lightweight and high-strength carbon fiber rope or the like for the diagonal stay rope.

[0017]

As described above, according to the present invention, twisting is prevented by extending the cross beams attached to the floor set and extending the reinforcing ropes on both sides of the floor set, and the left and right double-set floor sets are inclined. By connecting with a stay rope, deformation of the floor set due to the amount of wind load can be suppressed. That is, it can have a function equal to or more than that of the structure using the conventional storm rope, and the construction work related to the erection and removal of the storm rope becomes unnecessary, and the construction period can be shortened.

[Brief description of the drawings]

FIG. 1 is a detailed explanatory view of the vicinity of a tower in an embodiment of the present invention.

FIG. 2 is a plan view showing an implementation side where the oblique ropes of the present invention are provided on left and right hanging scaffolds.

FIG. 3 is a plan view showing an example of disposing an oblique stay rope according to the present invention.

FIG. 4 is a side view showing an example of arranging the oblique stay rope according to the present invention.

FIG. 5 is a plan view showing the configuration of the hanging scaffold of the present invention.

FIG. 6 is a cross-sectional view showing the configuration of the hanging scaffold of the present invention.

FIG. 7 is a diagram showing a relationship between torsional deformation of a floor set and a loaded load.

FIG. 8 is a diagram showing a relationship between a wind load and a floor group displacement.

FIG. 9 is a view showing the relationship between rope tension and wind speed for each material of the slant stay rope material.

FIG. 10 is a side view of the entire length of the suspended scaffold (a conventional storm rope is indicated by a dotted line).

FIG. 11 is a cross-sectional view of a suspended scaffold with a storm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Floor set 2 Reinforcement rope 3 Cross beam 4 Catwalk rope 5 Hanging scaffold 6 Storm rope 7 Hanger rope 8 Diagonal stay rope 9 Cross bridge 10 Tower 11 Main cable 12 Wire mesh 13 Square pipe 14 Wood 15 Handrail 16 Abutment

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinsuke Yamazaki 5-9-1 Nishihashimoto, Sagamihara City, Kanagawa Prefecture Nippon Steel Corporation Steel Structure Marine Division (58) Fields surveyed (Int. Cl. ⁷ , DB Name) E01D 21/00 E01D 11/00

Claims (3)

(57) [Claims] 1. A large number of catwalk ropes installed in parallel between towers or between a tower and an abutment are held by cross beams arranged at appropriate intervals in the bridge axis direction, and a floor set is fixed on an upper part. In a suspension scaffold for cable erection of a suspension bridge, a reinforcement rope is laid in parallel with the catwalk rope at intervals on both sides of a floor group of the suspension scaffold, and the reinforcement rope is fixed to an abutment or a tower portion. A hanging scaffold for cable erection, which is fixed to an end of the cross beam protruding from both sides of the hanging scaffold. 2. A diagonal stay rope is used to connect two sets of suspended scaffolds installed between the left and right towers or between the tower and the abutment with diagonal stay ropes.
The suspension scaffold for cable erection according to claim 1, wherein deformation due to wind is prevented. 3. The hanging scaffold according to claim 2, wherein a lightweight and high-strength fiber rope is used for the slanting stay rope.