JP2000257668A - Seismic force reduction method for railway viaduct - Google Patents

Abstract

(57) [Abstract] [Problem] To provide a method for reducing seismic force of a railway viaduct with low construction cost and short construction period. SOLUTION: The upper ends of the suspension members 2 and 2 having a predetermined length are attached to the railway frame viaduct 1, and the suspension members 2 and
The lower end of 2 is attached to a suspension 3 having a predetermined mass, the vibration at the time of the earthquake is transmitted through the suspension members 2, and the suspension 3 is vibrated to reduce the seismic vibration. Reduce seismic reinforcement or replace it with said seismic reinforcement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing seismic force acting on a railway.

[0002]

2. Description of the Related Art There is a demand for a railway viaduct, which is a structure supporting a railroad track, to further improve the strength in an earthquake. Currently, as the seismic retrofitting method for railway ramen viaducts, there are two methods: the steel plate winding method, in which the perimeter of the viaduct is wrapped with steel plates, and the reinforced concrete winding method, in which the perimeter of the viaduct is reinforced with reinforced concrete. The "standing construction method" and the "fiber winding method" in which the periphery of a pillar portion of a viaduct is wrapped with carbon fiber or aramid fiber to reinforce it, etc.

[0003]

However, the above-mentioned conventional seismic retrofitting method for railway viaducts has the following problems.

[0004] 1) Since it is necessary to provide seismic reinforcement for all pillars of the viaduct, in the case of a railway viaduct that is long in the track direction, the overall construction cost is high and the construction period is long.

[0005] 2) If equipment and devices are installed around the pillars of the viaduct, they need to be removed or relocated, which further increases both the construction cost and the construction period.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for reducing seismic force in a railway viaduct with a low construction cost and a short construction period. It is in.

[0007]

In order to solve the above-mentioned problems, a method for reducing seismic force of a railway viaduct according to the present invention is to attach one end of a suspension member having a predetermined length to the railway viaduct and to attach the suspension member to the railway viaduct. The other end is attached to a suspended body having a predetermined mass, vibration during an earthquake is transmitted through the hanging material, and the suspended body is vibrated to reduce the seismic vibration and reduce the seismic reinforcement of the railway viaduct. Or the above is replaced with the seismic reinforcement.

[0008] In the above-mentioned seismic force reduction method, preferably, the degree of reducing the seismic vibration is increased or decreased by adjusting the mass of the suspension body.

In the above-mentioned seismic force reduction method,
Preferably, the extent of reducing the seismic vibration is increased or decreased by adjusting the length of the suspension member.

In the above-mentioned seismic force reduction method,
Preferably, the suspension is provided for a predetermined use.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(1) First Embodiment FIG. 1 is a conceptual diagram showing a configuration of a railway viaduct according to a first embodiment of the present invention.

As shown in FIG. 1, a suspension 2 and a suspension 3 are attached to a railway frame viaduct 1 of the first embodiment. In FIG. 1, reference numeral 4 denotes a railway vehicle.
The suspension member 2 is configured by a steel member, a steel rod, a steel wire, a steel chain, or the like.

One end (upper end in the figure) of the hanging member 2 is attached to a lower portion of the upper floor, and the hanging member 2 can vibrate so as to swing about a point of attachment to the upper floor. . Further, the other end (the lower end in the figure) of the hanging member 2 is attached to a part of the suspension 3.

The suspension 3 is an object having a predetermined mass. Therefore, the system consisting of the suspension members 2 and 2 and the suspension 3
The weight system has a "vibration system" in which a weight having a predetermined mass is suspended so as to be capable of oscillating vibration. If the viaduct is the main system,
This vibration system is an “additional vibration system”, and the system composed of the railway frame viaduct 1 and the additional vibration system is a combined vibration system.

With the above configuration, when an earthquake vibration is applied from the ground G to the vibration system including the railway frame viaduct 1 and the additional vibration system, the seismic vibration is transmitted from the column portion of the railway frame viaduct 1 to the upper floor portion. And the hanging members 2 and 2 and the suspended body 3
Vibrate so that they swing together. Thereby, the energy of the earthquake is distributed to the additional vibration system including the suspension members 2 and 2 and the suspension 3.

Therefore, part of the seismic vibration energy applied to the railway frame viaduct 1 from the ground G is converted into kinetic energy when the additional dynamic system vibrates, so that the energy of the earthquake applied to the railway frame viaduct 1 is reduced. I do.

In general, in a vibration system having a mass m and a spring coefficient k, the vibration period T of the vibration system is expressed by the following equation (1) T = 2π × √ (m / k) (1) You.

Therefore, by adjusting the mass (weight) of the suspension 3, the vibration period of the entire vibration system (a system in which the additional vibration system is added to the viaduct 1) can be adjusted.

The spring coefficient k of the suspension 2 is such that when a horizontal force f is applied to the lower end of the suspension 2 attached to the lower part of the upper floor of the ramen viaduct 1, the lower end of the suspension 2 When displaced by δ in the horizontal direction, it is expressed by the following equation (2): k = f / δ (2)

In the above equation (2), the value of δ becomes larger as the length L of the hanging material is longer when the hanging material 2 has the same material and structure. That is, δ is proportional to L. Therefore, a
Is a constant, k can be represented by the following equation (3): k = a / L (3), and the spring coefficient k decreases as the length L of the hanging member increases.

Therefore, by adjusting the length of the suspension member 2, it is possible to adjust the vibration period of the additional vibration system and the entire vibration system (system obtained by adding the additional vibration system to the viaduct 1).

In this way, by adjusting the vibration period of the additional vibration system including the suspension members 2 and 2 and the suspended body 3 so that the frequency of the external force becomes equal to that of the external force, the external force is applied to the main system (via bridge). Then, the additional vibration system is excited.
This is the principle of an adjustable mass damper (TMD). Therefore, seismic energy can be transferred to this vibration system to reduce seismic vibration to the entire structure.

Further, when the additional vibration system vibrates in a long cycle, the overall structure of the viaduct and the additional vibration system vibrates in a long cycle. As a result, it is out of synchronization with the period of the seismic motion and becomes less susceptible to seismic force.

For this reason, the seismic reinforcement of the railway frame viaduct 1 can be reduced. Alternatively, by adding such a vibration system to the railway frame viaduct 1, seismic reinforcement of the railway frame viaduct 1 becomes unnecessary, and can be replaced with earthquake-resistant reinforcement.

The above-described seismic force reducing action is shown in FIGS. FIG. 3 is a diagram showing the relationship between the spring coefficient of the hanging material and the seismic force applied to the entire structure. Ci on the vertical axis indicates the coefficient of the seismic force applied to the structure. The larger the value, the greater the seismic force applied to the structure. The spring coefficient of the suspension is
It becomes smaller as the length of the hanging material 2 is longer. As shown in FIG. 3, by providing the additional vibration system, the seismic force received is smaller than that of the viaduct alone. In addition, as the spring coefficient of the suspension member is smaller and the length of the suspension member 2 is longer, the seismic force applied to the entire structure (viaduct + additional vibration system) decreases.

FIG. 4 is a diagram showing the relationship between the weight of the suspension 3 and the seismic force applied to the entire structure. Vertical axis Ci
Indicates the coefficient of the seismic force applied to the structure as in the case of FIG. As shown in FIG. 4, by providing the additional vibration system, the seismic force received is smaller than that of the viaduct alone. In addition, as the weight of the suspended body 3 increases, the seismic force applied to the entire structure (high bridge + additional vibration system) decreases.

(2) Second Embodiment FIG. 2 is a conceptual diagram showing a configuration of a railway viaduct according to a second embodiment of the present invention.

As shown in FIG. 2, suspension members 6, 6 and suspension members 7 are attached to the railway frame viaduct 11 of the second embodiment via attachment members 5 provided on the pillar portions. In FIG. 2, reference numeral 4 denotes a railway vehicle. The hanging material 6 is the first
It has the same configuration and operation as the hanging member 2 in the embodiment.

One end (the upper end in the figure) of the suspending member 6 is attached to a lower portion of the mounting member 5, and the suspending member 6 can vibrate so as to swing around a point of attachment to the attaching member 5. ing. Also, the other end of the hanging member 6 (the lower end in the figure)
Is attached to a part of the suspension body 7.

The suspension 7 is an object having a predetermined mass. Therefore, the railway ramen viaduct 11 is a “vibration system” in which a weight having a predetermined mass is suspended in a swingable manner.

With the above-described configuration, in the railway ramen viaduct 11 of the second embodiment, when an earthquake vibration is applied from the ground G, the seismic vibration is reduced to the railway ramen viaduct 1.
The suspension is transmitted from the first pillar portion to the mounting member 5, and vibrates so that the suspension members 6, 6 and the suspension body 7 swing together. Thereby, the energy of the earthquake is distributed to the vibration system including the suspension members 6 and the suspension 7.

Therefore, part of the seismic vibration energy applied from the ground G to the railway frame viaduct 11 is converted into kinetic energy when the vibration system vibrates, so that the energy of the earthquake applied to the railway frame viaduct 11 is reduced. .

In the case of the additional vibration system comprising the above-mentioned suspension members 6, 6 and the suspension body 7, the vibration cycle of the whole vibration system can be adjusted by adjusting the mass of the suspension body 7, or By adjusting the length of the members 6, 6, the vibration period of the entire vibration system can be adjusted.

In this way, by adjusting the vibration period of the additional vibration system composed of the suspension members 6, 6 and the suspended body 7 so that the frequency of the external force becomes equal to the frequency of the external force, the external force is applied to the main system (viaduct). Then, the additional vibration system is excited.
This is the principle of an adjustable mass damper (TMD). Therefore, seismic energy can be transferred to this vibration system to reduce seismic vibration to the entire structure.

Further, when the additional vibration system vibrates in a long cycle, the overall structure of the viaduct and the additional vibration system vibrates in a long cycle. As a result, it is out of synchronization with the period of the seismic motion and becomes less susceptible to seismic force.

For this reason, the seismic reinforcement of the railway frame viaduct 11 can be reduced. Alternatively, by adding such a vibration system to the railway frame viaduct 11,
The seismic reinforcement of the railway ramen viaduct 11 is unnecessary, and can be replaced with seismic reinforcement.

Also in the case of the second embodiment, the seismic force reducing action is as shown in FIG. 3 and FIG. Further, in the case of the second embodiment, the suspension 7 is a building or a utilization facility / equipment, and the space inside the suspension 7 is used for applications such as offices, commercial facilities, dwellings, etc. Can be used for applications such as railways. Thereby, the suspended body 7 can be used for multiple purposes, not just as a weight, and the space under the viaduct can be effectively utilized.

The present invention is not limited to the above embodiments. Each of the above embodiments is merely an example, and has substantially the same configuration as the technical idea described in the claims of the present invention, and those having the same functions and effects are:
Anything is included in the technical scope of the present invention.

For example, in each of the above-described embodiments, the railway ramen viaduct has been described as an example for reducing the seismic force. However, the present invention is not limited to this example, and a general railway viaduct including a girder viaduct can be used. May be targeted.

[0041]

As described above, according to the present invention,
The energy of the earthquake is transferred to the additional vibration system consisting of the hanging material and the suspended body to reduce it, and the additional vibration system is vibrated for a long period to vibrate the overall structure of the viaduct and the additional vibration system for a long period. Since the period is made different from the period of the seismic motion so that it is less affected by seismic force, the seismic reinforcement of the railway viaduct can be reduced. There is an effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a railway viaduct according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating a configuration of a railway viaduct according to a second embodiment of the present invention.

FIG. 3 is a diagram (1) illustrating an operation of the railway viaduct shown in FIGS.

FIG. 4 is a diagram (2) illustrating the operation of the railway viaduct shown in FIGS.

[Explanation of symbols]

 1, 11 Railway ramen viaduct 2 Suspended material 3 Suspended body 4 Railway vehicle 5 Mounting member 6 Suspended material 7 Suspended body G Ground

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinsawa Yamada 2-2-2, Yoyogi, Shibuya-ku, Tokyo East Japan Railway Company (72) Inventor Koichi Yoshida 2-chome, Yoyogi, Shibuya-ku, Tokyo No. 2 East Japan Railway Company F-term (reference) 2D059 BB37 GG14 GG55 3J048 AA07 AC10 AD05 BF10 BG10 DA01 DA07 DA10 EA39

Claims (4)

[Claims] 1. A suspension member having a predetermined length is attached to one end of a railway viaduct, and the other end of the suspension member is attached to a suspension body having a predetermined mass. A seismic force reduction method for a railway viaduct, wherein the seismic vibration is reduced by transmitting and vibrating the suspension body, and the seismic reinforcement of the railway viaduct is reduced or replaced with the seismic reinforcement. 2. The method for reducing seismic force of a railway viaduct according to claim 1, wherein the degree of reducing the seismic vibration is increased or decreased by adjusting the mass of the suspension. Reduction method. 3. The method for reducing seismic force of a railway viaduct according to claim 1, wherein a degree of reducing the seismic vibration is increased or decreased by adjusting a length of the suspension member. Reduction method. 4. The method for reducing seismic force of a railway viaduct according to claim 1, wherein the suspension is used for a predetermined use.