JP2013039873A - Seismic control beam and gate type beam including the seismic control beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the vibration of poles during an earthquake by absorbing the energy of vibration by dampers, which are expanded and contracted when poles are vibrated.SOLUTION: A seismic control beam 1 is disposed across a pair of the poles 2 provided vertically. The seismic control beam 1 includes a beam material 11, joints 3 that join the beam material 11 rigidly to the poles 2, and the dampers 4 disposed diagonally between the beam material 11 and the poles 2. A gate type beam includes a pair of the poles 2 provided vertically sandwiching a railroad track and the seismic control beam 1 disposed on the poles 2. This structure enables the vibration of the poles 2 to be controlled during an earthquake because the energy of vibration is absorbed by the dampers 4 that are expanded and contracted when the poles 2 are vibrated.

Description

  The present invention relates to a vibration control beam for suppressing vibration of a power pole during an earthquake, and a portal beam having the vibration control beam.

  Conventionally, as shown in FIG. 15, a utility pole 2 (electric pole) is provided on a railway train line. The utility pole 2 supports or holds the train line 21, the feeder 22 and the like, and is erected on both sides of the line in the double-track section. The utility pole 2 is often used because a concrete pole is less expensive than a steel pipe pole. When an earthquake occurs, the electric pole 2 on the viaduct 7 may have a greater seismic motion than the electric pole on the earth structure such as embankment or cutting. For this reason, in the elevated section of the Sanyo Shinkansen, assuming a Level 2 (L2) earthquake modeled after the Hyogoken-Nanbu Earthquake, seismic reinforcement is carried out on concrete columns whose moment exceeds the allowable moment. . In this assumption, it is considered that the vibration of the concrete pillar is reduced to about half by the train line. As earthquake-proof reinforcement, for example, a structure in which the vicinity of a column base portion of a concrete column is surrounded by an iron plate is known. However, depending on the viaduct, there are concrete columns that are difficult to implement such seismic reinforcement because the space around the column base of the concrete column is narrow.

  Further, in a railway train line, a gate-type beam is known in which a fixed beam is installed on a pair of utility poles erected between the tracks (for example, see Patent Document 1). The portal beam is considered to reduce the vibration of the power pole during an earthquake compared to a single power pole without a beam. However, it has not been known whether such a conventional portal beam is sufficient for seismic reinforcement.

JP 2002-295420 A

  This invention solves the said problem, and it aims at suppressing the vibration of the utility pole at the time of an earthquake.

  The seismic control beam of the present invention is constructed on a pair of standing electric poles, and includes a beam material, a joint for rigidly joining the beam material to the electric pole, and between the beam material and the electric pole. And a damper that is obliquely installed.

  Preferably, the vibration control beam has a long diagonal member fixed to the beam member, and the damper is obliquely provided on the beam member via the diagonal member.

  In this vibration control beam, the damper is preferably a friction history type damper.

  In this vibration control beam, it is preferable that the frictional hysteresis type damper generates a resistance force that is approximately proportional to the 0.1th power of the excitation speed.

  The portal beam of the present invention is characterized by having a pair of utility poles erected across a track and the vibration control beam erected on the utility pole.

  According to the present invention, when the utility pole vibrates, the damper is expanded and contracted to absorb the vibration energy, so that the vibration of the utility pole during an earthquake is suppressed.

The front view of the vibration control beam which concerns on one Embodiment of this invention. The top view of the damper in the damping beam. The front view of the damper. The figure which shows the hysteresis curve of the resistance force with respect to the displacement in the damper. The front view of the portal beam which has the seismic control beam. The graph of the approximate expression of the speed dependence of the resistance force in the damper of the damping beam. The front view which shows the model in the simulation of the portal beam which has the damper. The figure which shows the input earthquake waveform in the simulation. The perspective view which shows an example of a deformation | transformation of the portal beam in the simulation. The graph which shows the relationship between the damper displacement and damper angle in the same simulation. The graph which shows the relationship between the damper accumulated absorbed energy amount and damper angle in the simulation. (A) is a front view of the Example of this invention in an excitation experiment, (b) is a front view of the comparative example in the experiment, (c) is a front view of another comparative example in the experiment. The top view which shows arrangement | positioning of the Example and comparative example in the experiment. The figure which shows the input waveform of this vibration in the same experiment. The front view of the portal beam on the conventional viaduct.

  A vibration control beam according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the vibration control beam 1 is installed on a pair of standing electric poles 2. The utility pole 2 is not a component of the seismic control beam 1. The vibration control beam 1 includes a beam member 11, a joint 3 that rigidly joins the beam member 11 to the utility pole 2, and a damper 4. The damper 4 is provided obliquely between the beam material 11 and the utility pole 2.

  The beam material 11 is a highly rigid beam member that is installed near the top of the utility pole 2 across the railroad, and is a steel pipe in this embodiment. The beam material 11 may be a truss that combines steel materials.

  The joint portion 3 has a pair of substantially semi-cylindrical clamping members 31 and 32. Each clamping member 31 and 32 has a flange at the abutting portion. One clamping member 31 has the beam member 11 fixed thereto, and has a reinforcing rib at a fixed portion. The utility pole 2 is clamped by the clamping members 31 and 32 by surrounding the utility pole 2 with both clamping members 31 and 32 and fastening the flanges with bolts.

  The damper 4 absorbs vibration energy. The vibration control beam 1 has a long diagonal material 12 welded to the lower part of the beam material 11. The diagonal member 12 is a steel pipe and forms the same angle as the damper 4 with respect to the beam member 11. The vicinity of the lower end of the diagonal member 12 is fixed to the beam member 11 by a vertical member 13 made of a steel pipe. The damper 4 is obliquely provided on the beam material 11 via the diagonal material 12. The diagonal members 12 and the vertical members 13 may be trusses.

  As shown in FIGS. 2 and 3, the damper 4 includes a damper main body 41 and double clevises 42 and 43. One double clevis 42 is pin-bonded to one end of the damper body 41 and attached to the beam member 11 side, that is, the diagonal member 12. The other double clevis 43 is pin-joined to the other end of the damper body 41 and attached to the utility pole 2 by a member that sandwiches the utility pole 2.

  In this embodiment, the damper 4 is a friction history type damper, and absorbs vibration energy by the flow resistance force of the filler in the damper main body 41. As shown in FIG. 4, the friction history type damper generates a resistance force at an initial stroke, and the history curve of the resistance force against the displacement is substantially rectangular. The energy absorbed by the damper 4 is a value obtained by integrating the resistance force by displacement, that is, an area surrounded by a hysteresis curve. The friction history type damper has a high energy absorption rate because the history curve is substantially rectangular. The damper 4 is not limited to a friction history type damper, and may be, for example, an oil damper, a viscoelastic damper, or the like.

  In the seismic control beam 1 configured as described above, when the pair of utility poles 2 vibrate in the same phase in parallel with the beam member 11, the damper 4 is expanded and contracted to absorb the energy of the vibration. 2 is suppressed (see FIG. 1). Since the pair of utility poles 2 are joined by the beam material 11 and the joint portion 3, they hardly vibrate in the opposite phase parallel to the beam material 11. In addition, the vibration in the direction orthogonal to the beam material 11 generated in the utility pole 2, that is, the vibration in the direction along the train line supported by the utility pole 2 is reduced by the train line. Moreover, since the rigid structure is formed when the joint part 3 joins the beam material 11 and the utility pole 2 rigidly, the vibration of the utility pole 2 at the time of an earthquake becomes small. Since the damper 4 is obliquely provided on the beam member 11 via the diagonal member 12, the position where the resistance force of the damper 4 acts on the beam member 11 can be adjusted by setting the length of the diagonal member 12.

  FIG. 5 shows a portal beam constructed using the vibration control beam 1. The portal beam 5 includes a vibration control beam 1 and a pair of utility poles 2 erected between the tracks. The utility pole 2 is a concrete pole. A movable bracket 23 that supports the train line 21 is attached to the utility pole 2. When the feeder is provided in an aerial manner, the gate beam 5 has a tower 24 for hanging a feeder (not shown) on the vibration control beam 1. In the case where the feeder is an underground cable, the tower 24 is omitted.

  In the portal beam 5 configured as described above, the vibration of the utility pole 2 during an earthquake is suppressed by the damping beam 1. Since the seismic control beam 1 is installed at a position higher than the height range surrounded by the steel plate for seismic reinforcement, it can be used for the seismic reinforcement of the utility pole that is difficult to implement the seismic reinforcement enclosed by the iron plate. Since the vibration of the power pole 2 is suppressed by the damping beam 1, the vibration of the tower 24 is reduced and the vibration of the feeder is reduced.

  A numerical simulation was performed on the angle (damper angle) of the damper 4 with respect to the beam material 11 in the damping beam 1 of the present embodiment. This simulation will be described with reference to FIGS.

The damper 4 of the present embodiment generates a rated resistance force Fr = 50 kN when vibrated at a speed V = 0.1 m / s, and a rated resistance force Fr when vibrated at a speed V = 0.3 m / s. Generates 12% greater resistance. As shown in FIG. 6, the resistance force F [kN] of the damper 4 is approximated by a speed dependence equation proportional to the 0.1th power of the speed V [m / s], F = aV ^0.1 . a is a constant determined from the rated resistance force Fr and the speed V at that time, and is called a Bingham constant. In this simulation, dynamic analysis software capable of performing analysis considering speed dependence is used, and a model based on a speed dependence formula of F = aV ^0.1 is adopted for the damper 4. The characteristic of the damper 4 is not limited to this.

  A model of the portal beam 5 in this simulation is shown in FIG. The utility pole 2 was a concrete pole with a height of 9 m. The distance between the two utility poles 2 was 8.5 m. A seismic control beam 1 was installed at the top of the utility pole 2 (near the top of the pole). The beam material 11 of the damping beam 1 was horizontal. The damper 4 is provided obliquely on the beam material 11 via the diagonal material 12. The resistance force by the damper 4 acts on the beam material 11 at a position 4 m from the utility pole 2 to the center side. The damper 4 forms an angle θ [°] with respect to the beam material 11. In this simulation, the angle θ is variable. Moreover, in order to compare the influence by the presence or absence of the damper 4, it simulated also about the portal beam which does not provide the damper 4. FIG. Under the condition without a damper, a brace was rigidly joined between the beam member 11 and the utility pole 2. The brace forms an angle θ with the beam material 11.

  A simulation was performed in which the seismic waveform was input to the model of the portal beam 5 configured as described above, and was excited in the X direction parallel to the beam material 11. As shown in FIG. 8, the input seismic waveform is a level 2 (L2) earthquake ground motion.

  An example of deformation of the portal beam 5 when this seismic waveform is input is shown in FIG. This example is a simulation result under the condition that there is no damper and the angle θ between the beam member 11 and the brace 14 is 30 °. The shape of the portal beam 5 when no seismic waveform is input is shown by a one-dot chain line, and the shape of the portal beam 5 when the seismic waveform is inputted and deformed to the maximum is shown by a solid line. The top ends of the pair of utility poles 2 are displaced in the same direction.

  FIG. 10 shows the displacement [m] of the damper 4 of the portal beam 5. When the angle θ was 10 ° to 45 °, the damper 4 was displaced. When the angle θ is 30 °, the displacement of the damper 4 is maximized. The damper 4 generates a resistance force due to this displacement and absorbs vibration energy.

  FIG. 11 shows the cumulative absorbed energy amount [kJ] of the damper 4 of the portal beam 5. When the angle θ is 20 ° to 45 °, the damper 4 significantly absorbs vibration energy. When the angle θ is 30 °, the amount of accumulated energy absorbed by the damper 4 is maximized.

  Thus, in the case of “with damper”, the damper 4 absorbs vibration energy during an earthquake, and thus the vibration of the utility pole 2 is attenuated. In the “no damper” case, the brace does not absorb vibration energy. According to this simulation, from the calculation result of the accumulated absorbed energy amount of the damper 4, the damper 4 preferably forms an angle of 20 ° to 45 ° with respect to the beam material 11, and particularly preferably 30 °. The damper angle is not limited to this angle range.

  Excitation experiments were performed on a portal beam as an example of the present invention, a portal beam as a comparative example, and a single utility pole. This vibration experiment will be described with reference to FIGS.

As an example, a portal beam 5 having a vibration control beam 1 was manufactured as shown in FIG. As the utility pole 2, a prestressed concrete pillar (10-40-T11B) having an outer diameter of 40 cm and a length of 10 m was used. A prestressed concrete column is a concrete column in which a concrete member is prestressed with a tension wire. Reinforcing bars used are 69.86 kg of 9 mm diameter tension wire, 11.484 kg of non-tensioned wire having a diameter of 9.2 mm, and 14.982 kg of core rebar having a diameter of 3 mm. The concrete volume is 0.629 m ³ . The mass of the utility pole 2 is 1,660 kg. Table 1 shows the member characteristics of the utility pole 2.

  The bending moment Mc when the bending crack occurs is 74.6 kNm, and the column base bending edge strain at this time is compression 353 μst (microstrain) and tension 353 μst. The bending moment My at yield is 157.7 kNm, and the column base bending edge strain at this time is compression 1268 μst and compression 2991 μst. The bending moment Mu when the concrete strain of the compression edge reaches the ultimate strain is 228.0 kNm, and the column base bending edge strain at this time is compression 2795 μst and tension 7953 μst.

  A simulated weight 25 was attached at a position of 3000 mm below the top end of the pole 2. The simulated weight 25 simulates a load on a train line or the like supported by the utility pole 2.

  The utility pole 2 was inserted into a steel cylindrical fixing jig 61 and mortar was injected into the gap between the fixing jig 61 and the utility pole 2. The fixing jig 61 is fixed to the vibration table 6, and the utility pole 2 is fixed to the vibration table 6 via the fixing jig 61. Such fixing of the electric pole 2 simulates the throwing foundation of mortar filling in the Sanyo Shinkansen. The interval between the utility poles 2 was 3500 mm.

  The seismic control beam 1 was installed on two utility poles 2 fixed on a vibration table 6. The beam material 11 of the damping beam 1 was a steel pipe. The height of the beam member 11 was set to a position 500 mm below the top end of the pole 2. An oblique member 12 is welded to the beam member 11, and a damper 4 is attached between the oblique member 12 and one utility pole 2. The angle formed by the damper 4 and the beam material 11 was 30 °. The damper 4 was a friction history type damper having a rated resistance of 50 kN and having the same characteristics as the damper used in the simulation.

(Comparative Example 1)
As Comparative Example 1, a portal beam 105 having a fixed beam 101 was manufactured and fixed to the vibration table 6 as shown in FIG. The fixed beam 101 includes the beam material 11 and the joint portion 3, but does not include the damper 4 and the diagonal material 12. Other than that, it was the same as the example.

(Comparative Example 2)
As Comparative Example 2, as shown in FIG. 12C, a single utility pole 2 that is not reinforced with a beam was fixed to a vibration table 6. Other than that, it was the same as the example.

(Excitation experiment)
As shown in FIG. 13, the portal beam 5 of the example, the portal beam 105 of the comparative example 1, and the utility pole 2 of the comparative example 2 are arranged on the shaking table 6, and simultaneously subjected to various measurements. It was. The excitation was one-dimensional excitation in the horizontal X direction parallel to the beam material 11. The input waveform of this excitation is shown in FIG. This input waveform has an elastic acceleration response spectrum (Sp2) for an inland earthquake that is considered in the L2 ground motion (large-scale ground motion). The maximum acceleration in this excitation was variable. Table 2 shows the main experimental data for three representative cases among the vibration experiments performed. The unit of acceleration 1Gal is 0.01 m / s ² in SI units.

  Including the case not shown in Table 2, the maximum strain at the column base in the non-reinforcing comparative example 2 is the strain at Mc (Table) so that bending cracks do not occur in the utility pole 2 until the 350 Gal input of the input waveform Sp2. Excitation was performed while managing so as not to exceed 1). Next, 2547 Gal input excitation of the input waveform Sp2 was performed as a design wave assuming an L2 earthquake. Furthermore, the excitation of 3000 Gal input, which is about 20% higher than the design wave, was performed.

(Maximum response acceleration at the top of the column)
With 2547Gal input of the input waveform Sp2 which is a design wave, in Comparative Example 2, the maximum response acceleration of the pole top of the utility pole 2 is 7139Gal, and the maximum strain of the pole base (1.2m from the shaking table 6) is the strain at Mu. Beyond. Comparative Example 1 was 6415 Gal (90% of Comparative Example 2), and Example was 4242 Gal (59% of Comparative Example 2).

  With 3000 Gal input of the input waveform Sp2, in Comparative Example 1, the maximum response acceleration at the column top was 8123 Gal, and the maximum strain at the column base exceeded the strain at Mu. An Example was 5088 Gal and was suppressed to 63% with respect to the comparative example 1. In Comparative Example 2, the acceleration was lower than that at the time of 2547 Gal input, but this is considered to be because the electric pole 2 was plasticized and the rigidity was lowered because it reached Mu by the excitation of 2547 Gal.

(Maximum relative displacement of the column top to the shaking table)
With 2547Gal input of the input waveform Sp2 that is a design wave, in Comparative Example 2, the maximum relative displacement of the column top with respect to the vibration table 6 was 56.7 cm, and the displacement was greatly displaced. Comparative Example 1 was 24.3 cm (43% of Comparative Example 2) and Example was 24.7 cm (44% of Comparative Example 2), both showing good displacement suppression effects, and no difference between the two was observed. .

  With 3000 Gal input of the input waveform Sp2, Comparative Example 2 has a maximum relative displacement of 63.2 cm at the top of the column, Comparative Example 1 is 45.1 cm (71% of Comparative Example 2), and Example is 30.2 cm (Comparative Example 2). The displacement suppression effect by the vibration control beam 1 of the example was remarkable. This is because the maximum strain at the base of the column did not reach the strain at Mu when the input was 3000 Gal, but in Comparative Example 1, the pole 2 was plasticized because it greatly exceeded the strain at Mu. Conceivable.

(Maximum edge strain of power pole)
In Example, Comparative Example 1 and Comparative Example 2, the maximum edge strain of the utility pole 2 did not exceed the strain at Mc over the entire length of the column with the input waveform Sp2 of 350 Gal input.

  In Comparative Example 2, the maximum edge strain of the column base portion (1.2 m and 1.4 m from the vibration table 6) exceeded the strain at Mu, with 2547 Gal input of the input waveform Sp2 which is a design wave. In Example and Comparative Example 1, the maximum edge strain at the column base exceeded the strain at My but did not reach the strain at Mu.

  With 3000 Gal input of the input waveform Sp2, in Comparative Example 1, the maximum edge strain at the column base exceeded the strain at Mu, and the maximum edge strain at the column top exceeded the strain at My. In the examples, the maximum edge strain at the column base did not exceed the strain at Mu, and the maximum edge strain at the column top did not exceed the strain at My.

(Evaluation of vibration test results)
In the example having the seismic control beam 1 and the comparative example 1 having the fixed beam, the response of the concrete column is less than the ultimate strain (Mu) with respect to the 2547Gal input of the input waveform Sp2, which is a design wave, It was confirmed that it has seismic performance against earthquakes of the same level. In the embodiment having the seismic control beam 1, the response of the concrete column is less than the ultimate strain (Mu) even for the 3000 Gal input of the input waveform Sp2 exceeding the design wave, and for the earthquake exceeding the level of the Hyogoken Nanbu Earthquake Has also been confirmed to have seismic performance.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, the vibration control beam 1 may be installed on the utility pole 2 of a conventional line. Moreover, the electric pole 2 is not limited to a concrete pillar, For example, the combination pillar (cage-type iron pillar) comprised combining the angle steel and the grooved steel may be sufficient, and a steel pipe pillar may be sufficient. The seismic performance is further improved by installing the damping beam 1 on a steel pipe column or the like. The damper 4 may be provided obliquely between at least one of the pair of utility poles 2 and the beam material 11.

1 Damping Beam 11 Beam Material 12 Diagonal Material 2 Utility Pole 3 Joint 4 Damper 5 Gate Beam

Claims (5)

A seismic control beam built on a pair of standing poles,
Beam material,
A joint for rigidly joining the beam material to a utility pole;
A seismic control beam comprising a damper obliquely disposed between the beam material and a utility pole. It has a long diagonal material fixed to the beam material,
The vibration control beam according to claim 1, wherein the damper is provided obliquely to the beam material via the diagonal material.   The damping beam according to claim 1 or 2, wherein the damper is a friction history type damper.   4. The vibration control beam according to claim 3, wherein a resistance force generated in the friction history type damper is substantially proportional to a 0.1th power of an excitation speed. 5. A pair of utility poles erected across the track,
5. A portal beam comprising the vibration control beam according to any one of claims 1 to 4 installed on the power pole.

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