JP3973583B2 - Accidental equipment fall prevention methods on highways, bridges, high-speed railways, etc. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fall prevention method for incidental facilities on highways, bridges, high-speed railways and the like.
[0002]
[Prior art]
In highways, bridges, high-speed railways, etc., sound insulation walls, signs, lighting lights, etc. are installed as ancillary equipment, and such equipment falls with a fall prevention cord to deal with vehicle collision, earthquake, and fracture fatigue. It is customary to prevent this.
[0003]
The fall prevention cord is usually a wire rope, one end is connected to a fall prevention object, the other end is anchored to a fixed structure, and energy is absorbed when a load is applied. .
In that case, conventionally, the safety factor is designed to be 2 or more, and the fall energy is absorbed within the elastic region of the rope (shown by the number of the circle 1) as shown in FIG. And when energy absorption was not permitted with one rope, it was stretched more than a plurality of ropes.
[0004]
[Problems to be solved by the invention]
However, in this method of absorbing energy within the rope elastic region, the rope diameter increases and the generated tension increases from the viewpoint of energy absorption efficiency.
As a result, the workability deteriorated, and the anchor strength as the fixing portion had to be increased and increased in size in order to cope with the increase in the generated tension at the rope end. For this reason, construction costs increased, and the main bodies such as roads and bridges were adversely affected.
[0005]
The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to make maximum use of the energy absorption performance of the rope, to reduce the rope diameter and to reduce the generated tension, and to expressways and bridges, The object is to provide a fall prevention method for incidental facilities such as sound insulation walls, signs, and illumination lights in high-speed railways.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a structure in which one end is fixed to a fall prevention target incidental equipment having a columnar shape, a panel shape or the like so that no tension is generated in the normal state and the other end is a structure that supports the fall prevention target object. In the fall prevention device having a fixed wire rope, the wire rope is a relatively short wire rope having a predetermined length and a relative length having a length more than the length of the wire rope plus an extension amount. It consists of long ropes, and when the incidental equipment subject to fall prevention falls, the fall rope absorbs the fall energy within the plastic area until it reaches the yield point and plastically deforms and breaks so that the elongation continues. After that, the long rope absorbs the remaining fall energy and secondary fall energy absorbed by the short rope.
[0007]
[Action]
Conventional fall prevention devices for incidental facilities on highways, bridges, high-speed railways, etc. have captured energy absorption by ropes within the elastic region, but the present invention has changed its concept and made the plastic region an energy absorption range. Therefore, after using a plurality of ropes with long and short lengths to absorb the energy until the relatively short rope reaches the plastic zone and breaks, the remaining rope that this relatively short rope could not absorb Energy is absorbed by a relatively long rope.
Since the plastic region of the rope is used for energy absorption in this way, the energy absorption amount is 3 to 4 times that of the elastic region, and therefore the diameter of the rope to be used can be reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
2 and 3 show a first embodiment in which the present invention is applied to a fall prevention means for ancillary equipment on highways, bridges, high-speed railways, etc., where 1 is a road, 2 is a target equipment, and in this example is a sign post The sign body 2b is fixed to the upper part of the support 2a. The column 2a is fixed to a side wall (hand rail) 10 whose lower end rises from the road surface by a fixing bracket 20.
[0009]
Reference numeral 3 denotes a fall-preventing rope for preventing the sign from falling from the side wall 10, and a plurality of (two in the figure) wire ropes 3a and 3b are used. However, the wire ropes 3a and 3b have the same length. Instead, one wire rope 3b has a length L2 that is relatively larger than the length L1 of the other wire rope 3b. The length L2 of the wire rope 3b needs to be at least the length L1 of the wire rope 3a plus the amount of elongation until the wire rope 3a breaks, and an appropriate length may be added thereto.
[0010]
One end of each of the wire ropes 3a and 3b is connected to a support metal fitting 4 attached to an intermediate portion of the column 2a, and the other end is connected to left and right fixing metal fittings 5 and 5 fixed to a side wall 10. Since the fixing brackets 5 and 5 are located at an equal distance from the support column or the support bracket 4, the relatively short wire rope 3a is stretched in a substantially arcuate shape, while the relatively long wire rope 3b is suspended in a U-turn shape. Has extra length.
[0011]
FIG. 4 shows a second embodiment of the present invention. In this embodiment, a relatively long wire rope 3b is guided in a coil shape so as to surround the outer periphery of the short wire rope 3a.
In this aspect, the appearance of the fixing metal fitting is improved because the fixing bracket is provided on one side and the appearance is as if one cord is present. It can also prevent the extra length of the long rope from shaking, the resulting noise, and damage from collision with other objects.
[0012]
What is shown is only a few examples and is not limited thereto.
1) The configuration of the wire ropes 3a and 3b is arbitrary. The rope thickness is usually the same, but may be different.
2) Although the number of the wire ropes 3a and 3b may be one in appearance, at least two are required substantially. However, it may be increased according to the magnitude of energy to be absorbed. In other words, if the tension of the second rope does not satisfy the predetermined safety factor (usually more than twice), use the second rope up to the breaking zone and set the length of the second rope plus the length equal to or greater than the elongation. A third rope with it will be added. The same applies to the case of four or more.
3) The present invention is applied not only to prevent the signs and illumination lamps from falling, but also to prevent the sound insulation walls from falling.
[0013]
[Effect of the embodiment]
The operation of the present invention will be described by taking the first embodiment as an example. Under normal conditions, the sign is in the state shown in FIGS. Since it is fixed, no tension is generated in the wire ropes 3a and 3b.
If a vehicle traveling on the road crashes into the sign post 2a or an earthquake occurs, the post 2a is separated from the fixing bracket or from the fixing bracket 20 and tries to fall or fall relatively short. Tension is generated at both ends of the wire rope 3a. At this time, since the long wire rope 3b has a surplus length, no tension is generated yet.
[0014]
When drawing the load / elongation curve of the rope in the process of absorbing the fall energy by the wire rope, it is as shown in FIG. 5, and the elongation increases linearly in the elastic region, and the curve goes to sleep after the yield point. . Conventionally, the portion up to the middle of the straight line portion is regarded as the energy absorption range. However, in the present invention, since the long wire rope 3b has a length longer than the elongation of the short wire rope 3a, the short wire rope 3a. Exerts a primary absorption action, and absorbs the falling energy within a plastic region (indicated by the number of the circle 2) until it reaches the yield point and plastically deforms and breaks so that the elongation continues. It can be said that the short rope 3a functions as an auxiliary rope, and the long rope 3b finally functions as a main rope for preventing the fall.
[0015]
Since the long wire rope 3b has a length longer than the elongation of the short wire rope 3a in the installed state, a tension is generated immediately after the short wire rope 3a is extended to the break or immediately before the break, and the short wire rope 3a is The remaining energy absorbed is absorbed until it breaks. That is, it absorbs the residual fall energy and secondary fall energy of the object (here, the sign). In other words, falling energy = energy absorption in the elastic region + energy absorption in the plastic region, and energy is absorbed by the circled numbers 1, 2 and 3 in FIG. FIG. 6 shows a fall pattern.
Therefore, the possible absorbed energy of each rope can be utilized to the maximum, and when a load absorbed energy equivalent to the conventional one is obtained, a rope having a small diameter is sufficient.
[0016]
More specifically, in the present invention, it is an essential condition that the last rope (n + 1) can support the fall weight in the elastic region, and the rope length and energy absorption satisfying the following formula are realized.
Formula (1) W * S <Es1 + Es2 +. . . + Esn + Es (n + 1)
Formula (2) Esn = 1/2 · σ · P · ΔLn + α · P · LRn · γ
Formula (3) ΔLn = (1 + ε0) · LRn · σ · P / (E · A)
Formula (4) Es (n + 1) = 1/2 · P / ΔL (n + 1) / SF
Expression (5) ΔL (n + 1) = (1 + ε0) · LR (n + 1) · P / SF / (E · A)
[0017]
Here, W is the fall weight (N), S is the fall height (mm), s1 is the fall height of the first rope, s2 is the fall height of the second rope, and sn is the final 1 The fall height of the previous rope, s (n + 1) is the fall height of the final rope, E is the elastic modulus (N / mm ² ) of the rope, and σ is the coefficient at the elastic limit. 3 ≦ α ≦ 1.0. P is the rope standard breaking load (N), α is the efficiency in the plastic region, that is, the plastic deformation safety factor up to the rope breaking, and is usually 0.3 ≦ α ≦ 1.0. ΔL is the elastic elongation of the rope (mm), LR is the rope length (mm), γ is the elongation percentage of the rope in the plastic region (%), ε0 is the initial strain of the rope (%), SF is the safety factor of the rope, A is the cross-sectional area of the rope.
[0018]
Now, let us assume that the object is a sign or an illumination pillar (hereinafter referred to as a sign pillar), and the fall energy is absorbed by using two long and short ropes. That is, it is assumed that the short (auxiliary) rope is broken to absorb the fall energy, and then the remaining fall energy of the column is absorbed by the long (main) rope.
[0019]
Assuming that the falling energy of the marker column and the absorption energy of the rope (including the plastic region) are equivalent, the falling energy of the marker column is Es1 = W · S1, Es2 = W · s2, and ΣEs = Es1 + Es2.
Since the absorption energy of the short rope is a plastic region, it can be calculated by the following equation.
Er1 = 1/2 · σ · P · ΔL1 + α · P · LR1 · r
ΔL1 = (1 + ε ₀ ) · LR1 · σ · P / (E · A)
Since the absorption energy of the long rope is within the elastic range, it can be obtained by the following equation.
Er2 = 1/2 · P · ΔL2 / SF
ΔL2 = (1 + ε ₀ ) · LR2 · P / SF / (E · A),
LR1 is the rope length (mm) of the short rope, and LR2 is the rope length (mm) of the long rope.
[0020]
Now, the fall weight W is 2300 N, the drop height s1 (primary fall distance) is 2985 mm, the drop height s2 (secondary drop distance) is 626 mm, and the fall prevention rope has a configuration of 6 × 19, the rope diameter: 16 mm, Standard breaking load: 117000 N, effective area: 89 mm ² _, rope length (LR1) of 2500 mm as _a short rope and rope length (LR2) of 3000 mm as a long rope When r is 1.5%, the coefficient σ at the elastic limit is 0.7, the efficiency α in the plastic region is 0.9, the initial strain ε _{0 of the} rope is 0.5%, and the safety factor SF is 2. The falling energy of the marker column is Es1 = W · S1 = 686.6 kN · cm, Es2 = W · S2 = 144 kN · cm, and ΣEs = Es1 + Es2 = 830.5 kN · cm.
[0021]
The absorption energy of the fall prevention cord is ΔL1 = 68 mm and Er1 = 673.3 kN · cm in the short rope. In the long rope, ΔL2 = 58.3 mm and Er2 = 170.5 kN · cm. Therefore, the total absorbed energy ΣEr is 843.9 kN · cm. This is larger than 830.5 kN · cm of the drop energy ΣEs of the sign post, and it can be seen that the fall can be safely prevented.
[0022]
On the other hand, in the general-purpose method, if the rope's absorbed energy is equivalent to the fall energy of the object (in this example, the sign column) and the rope's absorbed energy (including the plastic zone), (1) (2) holds.
Formula (1) W * S = 1/2 * P * △ L * SF
Formula (2) (1 + ε ₀ ) · LR · P / (E · A)
[0023]
As shown in FIG. 7, when two wire ropes 3 a and 3 a having the same specifications as the present invention and having a length of 2500 mm are used as the fall prevention rope (comparative example), the absorbed energy is as follows. FIG. 8 shows a drop pattern in this comparative example.
[0024]
The drop energy W · S of the marker pillar is 686.6 kN · cm, and the absorption energy Er of the fall prevention cord is ΔL = 97.1 mm, so it is 284 kN · cm.
This is significantly lower than the falling energy W · S of the marker pillar: 686.6 kN · cm, so it is unqualified and cannot be dealt with unless the thickness is increased to increase the strength.
[0025]
【The invention's effect】
According to claim 1 of the present invention described above, a structure in which one end is fixed to a fall prevention target incidental equipment having a columnar shape, a panel shape or the like so that no tension is generated in a normal state, and the other end supports the fall prevention target object. A wire rope fixed to the wire rope, wherein the wire rope is a relatively short wire rope having a predetermined length, and a length more than the length of the wire rope plus an extension amount. When the incidental equipment falls, the short rope stretches to reach the yield point and absorbs the fall energy within the plastic zone until it breaks and plastically deforms so that the elongation continues. The long rope absorbs the remaining fall energy and secondary fall energy absorbed by the short rope, so the energy absorption performance of the rope can be used to the maximum and the rope diameter can be reduced. As a result, the generated tension can be reduced. Therefore, it is highly effective in preventing falling of sound insulation walls, signs, and lighting lamps as incidental equipment on highways, bridges, and high-speed railways. Is obtained.
[0026]
According to the second aspect of the present invention, since it looks like a single rope in appearance, the appearance is good, and an excellent effect is obtained that it is possible to prevent the excess length portion from shaking, the resulting noise, and damage caused by collision with other objects. It is done.
[Brief description of the drawings]
FIG. 1 is a load-elongation curve diagram showing an energy absorption mechanism by a conventional rope.
FIG. 2 is a front view showing an example of a fall prevention facility to which the present invention is applied.
FIG. 3A is a side view of a fall prevention equipment to which the present invention is applied, and FIG. 3B is a side view of a wire rope to be used.
FIG. 4 is a front view showing another example of the fall prevention equipment.
FIG. 5 is a load-elongation curve diagram showing the energy absorption principle of the present invention.
FIG. 6 is an explanatory diagram showing a fall pattern of the present invention.
7A is a front view of a fall prevention facility of a comparative example, and FIG. 7B is a side view.
FIG. 8 is an explanatory diagram showing a drop pattern of a comparative example.
[Explanation of symbols]
2 Target equipment 3a Short rope 3b Long rope

Claims (2)

Fall prevention with a wire rope fixed to a structure that supports the object to be prevented from falling, with one end fixed to a column-shaped, panel-like incidental facility so that tension does not occur under normal conditions In the apparatus, the wire rope is composed of a relatively short wire rope having a predetermined length and a relatively long rope having a length equal to or greater than the length of the wire rope plus an extension amount, and is a fall prevention target. When the incidental equipment falls, the short rope stretches, reaches the yield point, and plastically deforms and breaks until the elongation continues. A fall prevention method for incidental facilities on highways, bridges, high-speed railways, etc., characterized by absorbing the fall energy and secondary fall energy 2. The method of preventing incidental equipment falling on a highway, a bridge, a high-speed railway, or the like according to claim 1, including a form in which the long wire rope is positioned so as to go around the short rope.

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