JP2013117088A - Earthquake strengthening method of electric pole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakage of an electric pole even when a high acceleration acts.SOLUTION: In an earthquake strengthening method of an electric pole (20) built on a foundation part (10), support members (30) of displacement suppressing reinforcement materials (40, 50) are arranged and fixed at an appropriate interval from an upper end to a lower part of the electric pole, the displacement suppressing reinforcement materials are attached through the respective support members, a lower end of the displacement suppressing reinforcement material is fixed to the foundation part, and thus displacement of the respective parts of the electric pole is restrained.

Description

  The present invention relates to a seismic reinforcement method for preventing breakage of an electric pole used for supporting a train line or the like during an earthquake.

Electric poles are mainly used to support power supply lines that supply power to trains and are erected at predetermined intervals along the tracks. Such an electric pole is manufactured as a cylindrical concrete product by pouring concrete into a formwork in which PC steel wires are arranged, rotating the formwork in that state, compacting the concrete, and performing predetermined curing. . The concrete produced by such a method shows a fracture behavior called so-called explosion, which is pulverized at the moment when the limit of strength is exceeded, while it is dense and has high strength with little moisture. That is, it is a characteristic of high strength but small stickiness (brittleness).
For this reason, if an electric pole vibrates due to an earthquake, the concrete explosion will occur at the moment the critical displacement is reached, and the concrete will be crushed and broken. ing.

Seismic reinforcement of electrified poles has been implemented since the 1978 Miyagi-oki-oki earthquake and after the 1995 Hyogo-ken Nanbu earthquake. As a method of improving the seismic performance of the electric pole body, a method of filling the concrete by inserting reinforcing bars into the hollow part of the electric pole, winding up the outer circumference of the electric pole with a steel plate, and creating a gap between the steel plate and the electric pole A method of filling with mortar or the like has been implemented. In this case, the reinforcement countermeasure method has a safety factor of about twice or more with respect to the design working load.
Moreover, a sand foundation for filling sand around the electrification pillar is applied as a foundation structure of the electrification pillar on the viaduct. When the sand foundation behaves with a certain level of vibration, the thin mortar at the top of the foundation breaks down, and the pillar moves in the sand foundation and is input to the electricity pillar using the sand damping effect. It is intended to reduce the acceleration. The introduction of sand foundation was developed and applied in the 1978 Miyagi-oki earthquake, triggered by the damage of the Tohoku Shinkansen currently under construction.

The earthquake damage of a power pole on a viaduct has occurred in a relatively large earthquake in recent years. The generation mechanism of this power pole damage will be described with reference to FIG.
In FIG. 3, reference numeral 1 denotes a viaduct on which a train travels, and electric poles 3 are erected at predetermined intervals along the track. Reference numeral 5 denotes an insulator for insulation attached to the tip of the electric pole. When there is an input of ground motion as shown by waveform A, a horizontal motion component as indicated by arrow B and a rotational component as indicated by arrow C are added to the upper end of viaduct 1 so that the viaduct is indicated by a broken line. A large acceleration acts on the electric pillar 3 on the viaduct. As a result, the electric pole sways and deforms as indicated by the broken line, and breaks at the moment when the limit deformation amount is reached.

Such a large deformation of the electric pole is caused by the resonance of the viaduct and the electric pole, or the natural period close to the resonance. In addition, if the natural period of the viaduct is smaller than that of the electrified pillar, the natural period will increase if cracks occur in the pillar of the viaduct due to the earthquake, and the electrified pillar will shake greatly as it approaches the natural period of the electrified pillar. Break when the displacement is reached. When the electrification pillars built on the viaduct resonate, the response acceleration acting on the electrification pillar reaches 10G (G is gravitational acceleration).
It is impossible to cope with a response acceleration of 10 G by reinforcing measures such as a conventional method of winding up an electric pole with a steel plate or a method of filling a hollow portion with high-strength mortar.

The present invention is intended to solve the above-described problem, and an object of the present invention is to prevent breakage of an electric pole even when a large acceleration is applied.
For this purpose, the present invention provides a method for seismic reinforcement of an electrified column built on a foundation, by arranging and fixing support members for displacement suppression reinforcement at appropriate intervals from the upper end of the electrification column to each of the displacement suppression reinforcements. It is characterized in that the displacement of each part of the electrification column is constrained by attaching through the support member and fixing the lower end to the base part.
Further, the present invention is characterized in that the support member to which the displacement suppressing reinforcing material is attached is arranged such that the acceleration acting on the electrification column and the lower end portion and the upper end portion of the charge column having a large displacement are arranged at a small interval. And
In the invention, it is preferable that the reinforcing member for suppressing displacement of the electric pole is made of a steel material, a steel wire, or a synthetic fiber material.
Further, the present invention is characterized in that a damper is attached to the displacement suppressing reinforcing material.
Further, the present invention is characterized in that the displacement suppressing reinforcing material is disposed by spirally winding around the electric pole.
Further, the present invention is characterized in that the displacement suppressing reinforcing material is linearly arranged around the electrification column at a predetermined angular interval.

According to the present invention, displacement suppressing reinforcement members are arranged at appropriate intervals from the upper end to the lower side of the electric pole, and are attached to the lower supporting member sequentially from the upper end supporting member and fixed to the base portion, thereby reinforcing the displacement suppressing reinforcement. Since the displacement of each part of the electrification column is restricted by attaching the material, it is possible to suppress the displacement of the charge column even if a large acceleration is applied, and to prevent the breakage of the electrification column without cost.
Further, since the displacement suppressing reinforcing material may be simply attached to the support members arranged at appropriate intervals, it can be attached without affecting the various additives of the electric pole.

It is a figure explaining the example of the seismic reinforcement method of an electric pole. It is a figure explaining the other example of the seismic reinforcement method of an electric pole. It is a figure explaining the situation where the electric pole on a viaduct breaks by an earthquake.

Hereinafter, this embodiment will be described.
FIG. 1 is a diagram for explaining an example of the seismic reinforcement method for an electric pole according to the present invention.
As described above, when the electric pole is deformed by shaking due to an earthquake, it breaks at the moment when the limit deformation is reached. Therefore, in order to prevent the breakage of the electric pole due to the earthquake, it is only necessary to prevent the electric pole itself from swaying as much as possible even if the foundation such as a viaduct vibrates so as not to reach the limit displacement. Therefore, in this embodiment, the reinforcing material for constraining the amount of deformation of the electrification column during an earthquake is arranged.
In FIG. 1, support members 30 are attached to a plurality of locations at appropriate intervals from the upper end portion to the lower portion of the electrification column 20 built on the foundation portion 10. The installation interval of the support members is set as appropriate, such as narrowing at the lower end and upper end where the applied acceleration and displacement are large and widening the middle. The support member 30 is configured, for example, such that one end of a pair of semicircular arc bands facing each other is hinge-coupled, and a member capable of bolting each semicircular arc band free end is fixed to an electric pole and a support fitting is attached. To do. One end of a reinforcing member 40, 50 such as a steel material, a steel wire, or a wire made of synthetic fiber is attached to the support bracket of the support member at the upper end of the electric pole at a symmetrical position, and the electric pole is attached to each other. Are attached to the support metal fittings of the respective support members 30 and wound to the lower end of the electrification column, and the end portion is fixed to the base portion 10.

By wrapping the displacement suppression reinforcement in a helical manner in this way, the displacement of each part of the electrical pole is constrained by the reinforcement that is stretched between the support members, regardless of the direction in which the acceleration is applied to the electrical pole. Therefore, it can be suppressed within a limit displacement that causes breakage.
Note that the number of reinforcing materials such as wires is not necessarily two but may be one. Further, the number of the reinforcing members may be increased to be spirally wound. Further, for example, three reinforcing members may be called 120 ° intervals or four reinforcing members may be called 90 ° intervals. By attaching a plurality of reinforcing materials to each support member in a straight line from the upper end to the lower end of the electric pole at predetermined angular intervals and fixing them to the foundation, acceleration can be applied to the electric pole from any direction. Can also restrain the displacement. By restraining the displacement of the charge pole, the influence on the power pole foundation is also reduced, which is effective in preventing damage to the power pole foundation.

FIG. 2 is a diagram for explaining another example of the seismic reinforcement method for electric poles according to the present invention.
This example is obtained by adding a damper 60 made of an oil damper or the like as a vibration absorbing mechanism to the lower end portion of the reinforcing material in addition to the seismic reinforcement method of FIG. By disposing such a damper, even if a large acceleration acts on the electrification column and a large tensile force acts on each reinforcing member, the damper 60 can absorb and attenuate the force. Note that the damper is not limited to the lower end portion of the reinforcing material, and a plurality of dampers may be provided at arbitrary positions such as an intermediate portion of the reinforcing material.

DESCRIPTION OF SYMBOLS 10 ... Base part, 20 ... Electric pole, 30 ... Support member, 40, 50 ... Displacement suppression reinforcement material, 60 ... Damper

Claims (6)

In the seismic reinforcement method for electrified pillars built on the foundation,
Displacement restraint reinforcement support members are arranged and fixed at appropriate intervals from the upper end to the bottom of the electrification pole, and the displacement restraint reinforcement is attached through the support members and the lower end is fixed to the base portion to displace the displacement of each part of the electrification pillar. Seismic reinforcement method for electrified pillars, characterized by restraining.   The support member to which the displacement suppressing reinforcing material is attached is arranged such that the acceleration acting on the electrification column and the lower end portion and the upper end portion of the charge column having a large displacement are arranged at a narrow interval. Reinforcement method.   The method for seismic reinforcement of an electrified column according to claim 1 or 2, wherein the reinforcing member for suppressing displacement of the electrified column is made of steel, steel wire, or synthetic fiber material.   The seismic reinforcement method for an electrified column according to any one of claims 1 to 3, wherein a damper is attached to the displacement suppressing reinforcement material.   The seismic reinforcement method for an electrified column according to any one of claims 1 to 4, wherein the displacement suppressing reinforcing material is disposed by spirally winding around the electrified column. The seismic reinforcement method for an electric pole according to any one of claims 1 to 4, wherein the reinforcing member for suppressing displacement is arranged linearly around the electric pole at predetermined angular intervals.

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