JPH08144218A - Aerial stringing method while controlling tension of pilot rope by using helicopter - Google Patents

Abstract

PURPOSE: To extend wires at a long distance by winding a pilot rope on a drum for a wire extender with a constant-tension setting mechanism, installing the wire extender to a helicopter and adjusting the tension of the pilot rope at a plurality of times by the constant-tension setting mechanism in response to the wire extending distance of the pilot rope. CONSTITUTION: A wire extender 3 capable of controlling the tension of a rope is hung down from a helicopter 1, and a pilot rope 2 stringed to the wire extender 3 is mounted. A sandbag 4 tightly binding the start tip of the pilot rope 2 is dropped and fixed onto a scaffold 6A for a starting point side tower top 5A while making the helicopter 1 hover. The helicopter 1 is flown horizontally after fixing while the tension of the rope is adjusted several times in response to wire extending distances as operating the wire extender 3 in the airframe of the helicopter 1, and aerial wire extension is conducted towards an end-point side tower top 5B. The helicopter 1 reaches the end-point side tower top 5B, and the pilot rope 2 is taken onto a scaffold 6B for the end-point side tower top 5B, and fixed onto the scaffold 6B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helicopter aerial overhead wire method used for traveling a pilot rope in a cable construction work for a long suspension bridge or the like.

[0002]

2. Description of the Related Art When constructing a cable for a long suspension bridge, generally, first, a pilot rope, which serves as a foothold, is stretched over all the diameters, and a rope drive system (holing system) is installed using this, and the We will proceed with the construction of the catwalk and the main cable. In other words, crossing the pilot rope is a very important construction as the first step to connect spans, but on the other hand, it is affected by various factors such as topography, weather, sea conditions, and marine traffic conditions.
It is also a difficult work that requires quick and reliable construction.

In the past, when pilot pilots traveled over the sea, various methods such as a submarine withdrawal method using a tugboat, a floating method using a tugboat, a freehang method using a tugboat, and a freehang method using a floater crane were taken into consideration while taking into account the scale of the suspension bridge, location conditions, etc. The Tokai method has been adopted.
Since all of these construction methods are carried out using the surface of the sea, it has been obliged to shut down and regulate marine traffic.

In order to avoid the problem of closure / regulation for marine traffic, it has been considered to use a helicopter aerial overhead line, which has already been put to practical use in erection work of high-voltage power lines, as a pilot rope over the sea. In this aerial overhead wire method, first, place a drum around which a lightweight pilot rope (messenger rope) such as a thin nylon rope is wound on the ground near one tower, and connect one end of the pilot rope to a helicopter, Alternatively, fix one end of the pilot rope to one of the steel towers, load the drum on the helicopter, pull the pilot rope out of the drum according to the navigation of the helicopter, and pull the pilot rope between the steel towers. This is to connect wires of different diameters, pull them with a winch, etc., and finally connect the actual wires to make an overhead wire.

[0005]

The subject of this electric wire overhead wire is a scale of several hundred US even if the distance between the steel towers is long, and since the overhead wire is carried over the mountainous area or the forest area, it is necessary to use a helicopter to pull the overhead wire. Even if the pilot rope drooped (sag), it did not cause much trouble. However, when a pilot rope of a long suspension bridge is aerial overhead line by a helicopter, it becomes a long-span overhead line of 1,000 to 2000 m, which has not been experienced in the past, and in order to ensure the safety of marine traffic below the overhead line construction, It is necessary to strictly control the sag amount (droop amount) of the pilot rope, and there is also a problem to ensure the steering stability of a helicopter that horizontally flies while applying a predetermined tension to the pilot rope.

In order to deal with these problems, there are many unclear points in the mere diversion of the conventional electric wire overhead wire technology using a helicopter. Therefore, a plan to use an aerial overhead wire using a helicopter for the pilot rope of a long suspension bridge has been implemented. I couldn't get it. As a result of various experiments, the inventors reasonably solved the above problems and established an aerial overhead line technology for pilot ropes in long suspension bridges using helicopters that had never been used in the past, and established a 2000-class center span actual bridge. The result was applied and it succeeded.

[0007]

In the aerial overhead wire method for a pilot rope using a helicopter according to the present invention, a pilot rope using a lightweight and high-tensile material is wound around a drum of a wire drawing machine equipped with a constant tension setting mechanism. The wire drawing machine is attached to a helicopter, the helicopter is flown while the pilot rope is fed from the wire drawing machine, and the pilot rope is towed.
When a pilot rope is overhead-wired between the abutment of the suspension bridge and the top of the tower or between the tops of the suspension bridge, the pilot rope should be adjusted according to the extension distance of the pilot rope so that the sag amount of the pilot rope is within the control limit. The pilot rope is pulled while adjusting the tension with the constant tension setting mechanism. In addition, it is desirable to use a polyaramid fiber rope for the pilot rope using this lightweight and high tensile strength material. Also, the tension adjustment of the pilot rope is preferably performed multiple times.

[0008]

[Operation] If a lightweight and high-strength rope such as polyaramid fiber rope is used as the pilot rope, the weight is about 1/4 of that of a normal wire rope of the same strength.
About. In addition to this, as the pilot rope, one using carbon fiber may be used. If a rope with such characteristics is used as a pilot rope and stretched horizontally or diagonally in the air, the amount of sag due to its own weight can be significantly reduced, and a large traction tension can be exerted. Can handle.

Further, when a pilot rope is used for aerial overhead lines between tower tops or between abutments and tower tops using a helicopter,
It is necessary not to interfere with marine traffic such as ground facilities and ships below. For this reason, it is important to manage the amount of sag so that the pilot rope does not hang below a certain altitude limit for safety during aerial overhead line work.

The amount of sag of the rope stretched horizontally or obliquely in the air is determined according to the rope mass, the span (extended wire distance) and the rope tension. In the present invention, the wire extension provided with a constant tension setting mechanism capable of adjusting the traction tension inside the helicopter machine according to the wire extension distance of the pilot rope so that the sag amount falls within a predetermined control limit considering safety. The machine is attached to a helicopter to ensure helicopter handling stability.

[0011]

EXAMPLES A method for aerial overhead wire connection of a pilot rope by a helicopter according to the present invention will be described below based on an example in which a long suspension bridge having a total length of about 4000 m is used. Since this suspension bridge is built over the strait, which has very frequent sea traffic of approximately 1,400 ships a day, the conventional method of using a pilot rope to travel by sea will greatly affect sea traffic. The method of crossing the sea by the aerial overhead line using the helicopter of the invention was adopted.

FIGS. 1 and 2 show a state in which a pilot rope is installed in the air using a helicopter between the tops of a long suspension bridge with a center span of 2000 m. The procedure for this overhead line is as follows. As shown in FIG. 2, a wire drawing machine 3 whose rope tension can be controlled is suspended from a helicopter 1, and a pilot rope 2 to be installed on the wire drawing machine 3 is mounted. Next, while hovering the helicopter 1, the sand bag 4 to which the starting end of the pilot rope 2 is secured is lowered onto the scaffold 6A on the starting point side tower top 5A, and this is fixed to the scaffold 6A (step a). After this fixing, while the helicopter 1 is flying horizontally, the rope tension is adjusted several times according to the wire-drawing distance while operating the wire-drawing machine 3 inside the helicopter, and the wire is drawn in the air toward the end-side tower 5B. (Step b to step c). After arriving at the terminal-side tower 5B, the pilot rope 2 is taken in on the scaffold 6B of the terminal-side tower 5B and fixed on the same scaffold 6B. Immediately after this fixing, the rope cutter 7 mounted on the wire drawing machine 3 is operated by remote control from inside the machine to separate the pilot rope 2 and the helicopter 1 (step d).

FIG. 3 shows a large helicopter used in this embodiment. Helicopter 1 has a total length of 16.3 m and a rotor diameter of 1
It is a large machine with 5.6 m and an effective payload of 4,180 kg.
The maximum take-off weight of helicopters is specified by the outside temperature and altitude, and the loadable weight can be calculated from these. However, it is not sufficiently quantitatively grasped how much the horizontal pulling force like the extension of the pilot rope is.

Therefore, as shown in FIG. 4, an experiment was conducted in which tension was applied to the rope by a constant tension device 8 and the rope was towed by the helicopter 1. In this case, the rope tension is 300 kg,
The limit angle θ during traction was measured for each of 700 kg and 1000 kg. Rope tension T and limit traction angle θ
5 shows the relationship. The calculated values in the figure are obtained by using the relationship between the rope tension T and the nose down angle φ obtained in this experiment to find the limit performance line from the balance of forces. Maximum traction force at a traction angle θ = 0 degrees (horizontal) is 650 kg
Then, the maximum traction force increased as θ increased and was 1200 kg at 90 degrees (right angle). The final pulling angle θ is about 25 degrees when the wire drawing distance is 1000 m in this experiment.
The maximum traction force Tmax in this case was about 700 kg.

The helicopter 1 in the experiment can maintain the hovering state even with respect to the limit performance shown in the figure, and the aircraft can be smoothly rebuilt from this limit state, and sufficient steering stability is secured within this range. it can. In addition, in this experiment, we also conducted an unreliability test to see if the rope in the reel would get stuck during the wire extension when a long pilot rope was wound in multiple layers. At the same time, it was also confirmed that there was no trouble during the wire drawing if the wound wire was aligned and wound with a tension of about 70% of the maximum tension.

FIG. 6 shows a polyaramid fiber rope (trade name: Kepler rope manufactured by DuPont) used as the pilot rope 2. The outer diameter of this rope is 10m
m, the inner layer (8 mm diameter polyaramid fiber) 2a,
Middle layer polyester fiber 2b, outer layer urethane resin coating 2c
It is composed of three layers, and has a non-rotating type and waterproof structure. The pilot rope 2 has a mass of 91.7 g / m, and has a tensile strength of 46 KN (4.7 tf), which is an ultralight weight and an ultrahigh strength.

FIG. 7 is a front view of the wire drawing machine 3 used in this embodiment, and FIG. 8 is a right side view of the wire drawing machine 3. The wire drawing machine 3 includes a drum 3a around which the pilot rope 2 is wound, a disc brake mechanism 3b for feeding the pilot rope 2 with a constant tension, and a rope cutter 7 that cuts the pilot rope 2. The disc brake 3b can be remotely adjusted inside the helicopter 1, and the setting of the feeding tension of the pilot rope 2 can be freely changed according to the wire extension distance. Similarly, the rope cutter 7 is also operated from inside the machine. Wire drawing machine 3
A constant tension mechanism other than the disc brake system may be used.

In the present invention, the wire drawing machine 3 is hung on the helicopter 1 and the pilot rope 2 is extended while feeding the wire. However, the wire drawing machine 3 is installed on the top 5A or 5B of the tower and the end of the pilot rope 2 is connected to the helicopter. There is also a method of fixing it on the 1st side and connecting it to the overhead line. However, in the latter case, it is necessary to adjust the rope tension at the top of the tower by using communication such as radio communication with the pilot of the helicopter 1 to make an overhead line, and to deal with communication troubles, changes in weather conditions, aircraft troubles, etc. In the former case, that is, it is preferable to attach the wire drawing machine 3 to the helicopter 1 side and let the helicopter side perform the overhead line work as in the present embodiment.

The problem in the case of aerial overhead line of the P rope 2 by the helicopter 1 is how the structure on the ground or the sea,
It is to work without hindering mobile equipment and people. Pilot rope 2 below a certain altitude limit H
As a method of managing the pilot rope 2 so that it does not decrease, the lowest point of the pilot rope 2 is monitored from the nearby ground, etc., and the feeding speed V and the tension T of the pilot rope 2 are monitored while contacting the line drawing operator of the helicopter 1 one by one. How to control. There are two methods: the relationship between the sag amount S of the pilot rope 2, the tension T, and the wire-drawing distance L is confirmed in advance by calculation or experiment, and the wire-drawing machine 3 is operated along with this.

In the method of (1), there is a time lag due to communication between the monitoring staff and the wire drawing operator, so that it is difficult to deal with it immediately. On the other hand, the method (1) can be said to be excellent because the sag amount S of the pilot rope 2 can be predicted in advance and an aerial overhead wire can be made in consideration of the safety. However, even in this method, it is considered that the sag amount S exceeds the control limit and falls below the altitude limit H due to a machine error of the wire drawing machine 3, a time lag during operation by an operator, or the like. In the present invention, based on the knowledge obtained from the experiments on the scale of the actual bridge, as a means for safely performing the aerial overhead line by the helicopter 1, the sag amount S of the pilot rope 2 to be overhead is
The tension T was adjusted a plurality of times in accordance with the wire extension distance of the pilot rope 2 so that the value was within the control limit.

The rope tension control in the aerial overhead wire method for the pilot rope 2 using the helicopter 1 will be described below. The rope that is stretched horizontally or diagonally in the air is
The sag amount (droop amount) S is determined according to the rope mass, the wire extension distance L, and the rope tension T. FIG. 9 illustrates this relationship. When a rope with a constant mass is used, the rope stretched from the 0 point is T at the A point of the extended wire distance LA.
_With a rope tension of ₁ , the sag amount is S ₁ , and with a rope tension T ₂ smaller than T ₁ , the sag amount is S ₂ larger than S ₁ . Further, at point B of LB where the wire extension distance is longer than LA, the sag amount becomes larger than S _{1 at} S _{3 at the} same rope tension T ₁ as at point A, and at T ₂ becomes larger than S _{2 at} S ₄ .

As can be seen from FIG. 9, in order to keep the sag amount S within the control limit, the tension T of the pilot rope 2 is increased, and this tension T is at the end point of the overhead line where the extension distance is maximum. It is conceivable that the tension Tmax of the pilot rope is set to match the maximum sag amount Smax, and the pilot rope 2 is towed with this tension Tmax from the beginning.

However, in such a method, it is necessary to use a rope having a large tensile strength, and the rope mass increases correspondingly, resulting in a vicious cycle in which the sag amount increases. In addition, it becomes necessary to use a large helicopter having a large traction force, resulting in poor workability. Furthermore, in the case of long-distance wire extension, it is necessary to carry out horizontal flight of the helicopter 1 along a predetermined route while applying a large rope tension Tmax for a long time.
There is a problem with flight stability (especially difficult operation at the flight start point where the wire distance is short). For this reason, in the present invention, the rope tension T is increased several times in accordance with the wire extension distance of the pilot rope 2.

FIG. 10 is data showing the results of adjusting the rope tension T according to the wire extension distance in an experiment on an aerial overhead wire of 1000 m. case A has a tension T of 50 kg to 33
In case B, the tension T was changed 7 times, and in case B, the tension T was changed 7 times in the range of 190 kg to 450 kg. As can be seen from this data, in case A, the variation amount ΔS (dotted line width) of the sag amount is large and exceeds the sag management target value of 35 m, but in case B, the variation amount is small and is well within the management target. There is.

The rope tension has an error with respect to the set tension T due to the performance of the wire drawing machine 3, the vibration of the pilot rope 2, the speed unevenness of the helicopter 1, and the like. As can be seen from FIG. 9, the variation amount of the sag S due to this error is smaller when the rope tension is larger for the same tension variation ΔT. Therefore, the rope tension T during the drawing is set to be as high as possible. The maximum tension Tmax of the pilot rope 2
Must be determined in consideration of safety so that the nose-down angle of the helicopter 1 does not increase and flight stability is impaired. Approximately 200 in a 4000m class bridge
The rope tension T is 500m in the overhead wire with a center span of 0m.
Adjustment was performed 3 times at intervals of 50 kg to 250 kg. Further, if the tension switching timing is shifted during the wire extension, the control limit may be interrupted. Therefore, as shown in FIG.
j (j = 1,2 ... n) was put in the pilot rope in advance, and the tension was switched while checking the mark Mj. In FIG. 12, reference numeral M _E is a mark indicating the final reaching point.

FIG. 11 shows changes in the altitude of the pilot rope 2 (distance from the water surface at the bottom end of the rope) due to changes in the sag amount S due to the adjustment of the wire-drawing distance L and the rope tension T. In the figure, the sag amount S is close to the limit value (route limit height +65 m) at the final reaching point. This seems to represent the difficulty in fixing the pilot rope 2 for taking in.

Regarding the operation of the helicopter 1, the most difficult thing was to hover while maintaining the maximum tension Tmax at the end point side tower top 6B. In the state where the helicopter 1 cannot be stopped at a fixed position and moves left and right, front and rear,
In addition to the risk of contact with the tower top structure, the fixing work cannot be performed on the tower top. In order to carry out a constant hovering stop, it is preferable that the pilot maneuver so as to keep the relative distance constant while looking at the nearest structure. this time,
As the visual key, the boom of the tower crane 10 is applied, and the setting angle and position of the boom are as follows.
The helicopter was actually hovered at the top of the tower in advance, and it was decided after confirming whether or not it could be sufficiently handled. It should be noted that the aerial overhead wire between the side spans had a risk of the pilot rope 2 coming into contact with the rear wing of the helicopter 1 when flying downward, so from the abutment 9A to the tower top 5A and from the abutment 9B to the tower top 6B. I mean, I went up.

[0028]

In the aerial overhead wire method for a pilot rope using a helicopter according to the present invention, a lightweight and high-strength rope is used for the pilot rope, so that the sag amount due to the weight of the rope is reduced and a large traction force is applied. It has become possible to extend long distances. In addition, since the overhead wire is adjusted while adjusting the tension of the rope multiple times so that the sag amount falls within the control limit according to the wire extension distance, the flight stability of the helicopter is ensured, and during the overhead wire work. Can ensure the safety of marine transportation of ships.

[Brief description of drawings]

FIG. 1 is an overall perspective view of an embodiment in which the aerial overhead wire method for a pilot rope by a helicopter of the present invention is applied to a long suspension bridge.

FIG. 2 is a main part front view showing a procedure of an overhead line work in the embodiment.

FIG. 3 shows the helicopter used in the above-mentioned embodiment and its specifications.

FIG. 4 is a schematic diagram showing an experimental situation of rope towing by horizontal flight of a helicopter.

FIG. 5 is a graph showing the result of the traction experiment as a relationship between the rope traction angle θ and the maximum traction force Pmax.

FIG. 6 is a side view of the pilot rope used in the embodiment.

FIG. 7 is a front view of the wire drawing machine with a constant tension mechanism used in the embodiment.

FIG. 8 is a right side view of the wire drawing machine with the constant tension mechanism.

FIG. 9 is an explanatory diagram showing a relationship between a wire extension distance of a pilot rope, rope tension, and a change in sag amount.

FIG. 10 is a graph showing the relationship between the wire extension distance, rope tension, and change in sag amount in the towing experiment.

FIG. 11 is a graph showing the relationship between the rope tension adjustment of the actual bridge and the change in the sag amount in the example.

FIG. 12 is a side view of the pilot rope used in the above embodiment, in which a mark indicating a tension switching point is provided.

[Explanation of symbols]

 1 Helicopter 2 Pilot rope 3 Wire drawing machine 4 Sandbag 5A Start point side tower 5B End point side tower 6A Start point side tower scaffolding 6B End side tower top scaffolding 7 Rope cutter 8 Constant tension setting mechanism 9A Start point side abutment 9B End point Side abutment 10 Tower crane 11 Heliport 12 Ship Mj Tension switching point mark

 ─────────────────────────────────────────────────── ─── Continuation of front page (71) Applicant 000006655 Nippon Steel Co., Ltd. 2-3-6 Otemachi, Chiyoda-ku, Tokyo (72) Inventor Hosokawa 2-6-3 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Steel Co., Ltd. (72) Inventor Yasuhiro Kishi 2-6-3 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Steel Co., Ltd. (72) Takuo Sugita 2-6 Otemachi, Chiyoda-ku, Tokyo No. 3 Inside Nippon Steel Co., Ltd. (72) Koji Kawaguchi 1-66 Hiraiso, Tarumi-ku, Kobe-shi, Hyogo Prefecture Honshu-Shikoku Communication Bridge Public Corporation First Construction Bureau Tarumi Construction Office (72) Inventor Iwa Yoshida Tokyo 3-1-1, Irifune, Chuo-ku, Tokyo Stock company Honshu-Shikoku connecting bridge engineering (72) Inventor Shunichi Kuwamoto 1-3-18, Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo Stock society Inside the Kobe Steel Works (72) Inventor Yasushi Yamashita 1-3-18 Wakihama-cho, Chuo-ku, Kobe City, Hyogo Prefecture Inside the Kobe Steel Works (72) Inventor Ichiro Takahashi Shin-Kiba 4-chome, Koto-ku, Tokyo Tokyo Heliport Toho Airlines Within

Claims (2)

[Claims] 1. A lightweight, high-strength pilot rope is wound around a drum of a wire drawing machine having a constant tension setting mechanism, the wire drawing machine is attached to a helicopter, and the pilot rope is removed from the wire drawing machine. While extending the helicopter, pull the pilot rope and pull the pilot rope in the air between the abutment of the suspension bridge and the tower top or between the tower tops so that the sag amount of the pilot rope is within the control limit. The method of pulling the pilot rope while adjusting the tension of the pilot rope by the constant tension setting mechanism according to the extension distance of the above, the method of performing the aerial overhead wire while managing the tension of the pilot rope using a helicopter. 2. The aerial overhead wire method for a pilot rope using a helicopter according to claim 1, wherein a polyaramid fiber rope is used as the pilot rope.