JP6508819B2 - Vibration control structure for bridge and setting method of vibration control structure for bridge - Google Patents

Description

  The present invention relates to a connection damping structure for a bridge and a setting method of the connection damping structure for a bridge.

BACKGROUND ART Conventionally, as a technology for making a bridge such as a viaduct into a vibration control structure, a vibration control technology in which a vibration control damper is installed between bridge girder is known (see, for example, Patent Documents 1 and 2).
In patent documents 1 and 2, the form which connects between girder-girders with a damper is illustrated in the bridge pier upper part, and it is possible to lengthen a structure or to control the vibration of the whole bridge to improve earthquake resistance. However, there is no description on specific damper settings and effects. As a matter of course, when both bridge girders have the same vibration, there is no damping effect even if they are connected by dampers, and the relationship between the vibration characteristics of the bridge structure and the amount of dampers is important.

Unexamined-Japanese-Patent No. 2004-332478 JP 10-183530 A

However, in the damping technology that connects adjacent bridge beams of a conventional bridge, it becomes possible to apply only when adjacent bridge beams have different vibration characteristics, that is, when the natural frequency is different, and the natural frequency is In the same case, there is a problem that they shake together and can not exert a damping effect.
In addition, there are few cases where the vibration characteristics between the existing adjacent bridges differ significantly, and the response reduction effect by the connection vibration control is limited, so there is room for improvement in that respect.

  The present invention has been made in view of the problems described above, and can be applied more effectively to bridges that are applied more effectively even when adjacent bridge girders have the same vibration characteristics (in the case where the natural frequency is the same). It is an object of the present invention to provide a method of setting a vibration control structure and a connection vibration control structure for a bridge.

In order to achieve the above object, in the connection damping structure for a bridge according to the present invention, one end side is connected to one adjacent first bridge girder part and the other end side is connected to the other second bridge girder part. And installing a plurality of bearings between each of the bridge girder parts and the lower structure, and installing a damping device in parallel with at least one of the bearings. A spring member or an inertia mass damper is provided as the vibration damping device, and a damper material has a peak value of the response magnification in the frequency transfer function of the first bridge girder portion and the second bridge girder portion is minimized. It is characterized by being set .

Further, the method of setting a connection vibration control structure for a bridge according to the present invention is the method for setting a connection vibration control structure for a bridge described above, wherein the natural frequency of the first bridge girder is the natural vibration of the second bridge girder. When the number is larger than the number, the inertia mass damper is disposed in parallel with only the support on the second bridge girder side, and the spring member is disposed in parallel with only the support on the first bridge girder side. And the inertia mass damper is disposed in parallel with only the support on the second bridge girder side, and the spring member is disposed in parallel with only the support on the first bridge girder side. It is characterized in that one is selectively provided.

  In the present invention, when the vibration characteristics of both adjacent bridge girder parts are the same, that is, even when the natural frequency is the same, both vibration characteristics (natural frequency) can be changed, and a large response reduction effect can be obtained. be able to. Therefore, it is possible to effectively solve the problem that the vibration control effect can not be obtained when the vibration characteristics of both adjacent bridge girder parts are the same as in the conventional case, as in the case of the vibration control using only the vibration control damper.

  Furthermore, in the present invention, in addition to the spring member as an damping device, an inertial mass damper is added, that is, when both of the vibration characteristics are changed by using both the spring member and the inertial mass damper Maximum response displacement is greatly reduced. In addition, the stress generated in the bridge is also greatly reduced, and the shear force acting on the foundation can be reduced as well. In addition, in the case where the spring member and the inertia mass damper are used in combination as the damping device, the convergence of the swaying becomes faster than when only the spring member is added.

In addition, since it is not necessary to replace the bearing but merely to add a damping mechanism, the bridge can be used continuously even during construction.
In addition, since vibration damping dampers are provided so as to connect adjacent bridge girder parts, and because the vibration control device is a relatively simple task of arranging in parallel with the bearing, no special skills are required for construction, and new construction is required. Not only is there an advantage that it can be applied to damping improvement of existing bridges.

  According to the connection vibration control structure for a bridge and the setting method of the connection vibration control structure for a bridge of the present invention, even when adjacent bridge beams have the same vibration characteristics (in the case where the natural frequency is the same), more effective application can do.

It is a figure which shows the connection damping structure (a) with respect to the bridge by embodiment of this invention, and this vibration-analysis model (b). It is sectional drawing which shows an example of the inertial mass damper of the damping structure of a bridge. It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the relationship between vibration frequency ratio and acceleration response magnification. It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the relationship between vibration frequency ratio and acceleration response magnification. It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the relationship between excitation frequency ratio and displacement response magnification. It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the relationship between excitation frequency ratio and displacement response magnification. It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the relationship between excitation frequency ratio and displacement response magnification. It is a figure which shows the waveform of the input earthquake motion used by simulation which confirms the seismic performance of the bridge which provided the connection damping structure with respect to a bridge. It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history acceleration response waveform of one bridge girder part (mass point 1). It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history acceleration response waveform of one bridge girder part (mass point 1). It is a result of the simulation performed in order to confirm the seismic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history acceleration response waveform of the other bridge girder part (mass point 2). It is a result of the simulation performed in order to confirm the seismic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history acceleration response waveform of the other bridge girder part (mass point 2). It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history displacement response waveform of one bearing part (mass point 1). It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history displacement response waveform of one bearing part (mass point 1). It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history displacement response waveform of the other bearing (mass point 2). It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure, and is a figure which shows the time history displacement response waveform of the other bearing (mass point 2). It is a result of the simulation performed in order to confirm the aseismatic performance of the bridge which provided the connection vibration control structure to the bridge, and is a figure showing time history relative displacement (relative displacement between beams) of adjacent bridge girder parts. It is a result of the simulation performed in order to confirm the seismic performance of the bridge which provided damping structure of the bridge, and is a figure showing time history shear force response waveform of a bridge leg. It is a result of the simulation performed in order to confirm the seismic performance of the bridge which provided damping structure of the bridge, and is a figure showing time history shear force response waveform of a bridge leg.

  Hereinafter, a connection damping structure for a bridge and a method of setting the connection damping structure for a bridge according to an embodiment of the present invention will be described based on the drawings.

As shown in FIG. 1 (a), the connection vibration control structure A for the elevated bridge according to the present embodiment is, for example, a bridge girder portion (bridge girder) in the upper structure 1A in the bridge 1 such as elevated bridge of multi-span continuous girder type. In order to bridge 2 and 3 each other, in other words, one end side is connected to one bridge girder part 2 adjacent in the bridge axis O1 direction and the other end side is connected to the other bridge girder part 3 so that the damper shaft is almost in the bridge axis O1 direction The vibration control damper 4 is disposed along the line.
And in connection damping structure A of this embodiment, while installing supporters 5 (5A and 5B) between each of bridge girder parts 2 and 3 and lower structure 1B, at least one of these bearings 5A and 5B is installed. Damping device 6 (6A, 6B) is installed and configured to be arranged in parallel with one side (both in the present embodiment).

  In the present embodiment, although the damping damper 4 is described as a viscous damper such as an oil damper, the damping damper according to the present invention is a viscosity of an oil damper or the like that generates a reaction force proportional to relative speed. Other than the damper, for example, an inertial mass damper that generates a reaction force proportional to relative acceleration between adjacent bridge girder parts 2 and 3, a spring member that generates a reaction force proportional to relative displacement, or an elastic-plastic damper is of course applicable. It is.

  In addition, since the vibration damping device 6 arranged in parallel to the supports 5A and 5B is targeted to the bridge leg 7 (lower structure 1B) under the continuous part of the bridge girder parts 2 and 3 (upper structure 1A), A spring member 6A is provided as a damping device on one side in the direction of the bridge axis O1 (left side in FIG. 1A) sandwiching the portion 7, and control on the other side (right side in FIG. 1A). An inertial mass damper 6B is applied as a vibration device. That is, in the present embodiment, the spring member 6A and the inertia mass damper 6B are used in combination as the damping device.

  In the present embodiment, the spring member 6A and the inertia mass damper 6B are used in combination, but the method of setting the damping device 6 is not limited to using both 6A and 6B in combination. For example, in the case where the natural frequencies of the bridge girder parts 2 and 3 satisfy the relation of first bridge girder part 2 ≧ second bridge girder part 3, the inertia mass damper 6B is used as the second bridge leg 3 of the second natural side A configuration in which only the two bearings 5B are disposed in parallel or a configuration in which the spring members 6A are disposed in parallel with only the first bearings 5A of the first bridge girder part 2 on which the natural frequency is not small can be adopted.

  Here, an example of the inertial mass damper 6B provided on the other side of the present embodiment is shown in FIG.

  The inertial mass damper 6B includes a ball screw 10 provided coaxially with the central axis O2 of the inertial mass damper B2, and a ball nut 11 provided by screwing on the ball screw 10. It comprises a rotating weight 12 attached to the ball nut 11 and rotated following the rotation of the ball nut 11.

  At one end 10 a of the ball screw 10, a connecting member 13 such as a ball joint or a clevis for connecting to the upper structure 1 A or the lower structure 1 B of the bridge 1 is attached.

  Further, the ball nut 11 screwed to the ball screw 10 is supported by the bearing 14. The bearing 14 is an annular outer ring 14a fixed non-rotatably around the axis O2 and immovable in the direction of the axis O2, and is disposed in the inner hole of the outer ring 14a and rotatably supported around the axis O2 It is formed to have an annular inner ring 14b. The ball screw 10 is inserted through the center hole of the inner ring 14 b of the bearing 14, and the ball nut 11 is fixed to the inner ring 14 b of the bearing 14. Thus, the ball nut 11 is disposed rotatably around the axis O2 and immovable in the direction of the axis O2.

  Further, a rotary weight 12 is integrally fixed to the ball nut 11. The rotary weight 12 is formed, for example, in a substantially cylindrical shape, and the ball screw 10 is inserted inside, and the ball screw 10 and the axis line O2 of each other are coaxially disposed and fixed to the ball nut 11.

Further, on the other end side of the inertia mass damper 6B, that is, on the other end 10b side of the ball screw 10, a cylindrical body 15 formed in a cylindrical shape is provided.
The cylindrical body 15 is a hollow cylindrical body having a predetermined length, high-axis rigidity and high bending rigidity, and a disc-shaped connecting plate 17 so as to close the inside to the other end (end on the left side in the drawing) 15a. A connecting member 18 such as a ball joint or clevis for connecting the other end of the inertial mass damper 6B to the lower structure 1B or the upper structure 1A of the bridge 1 is attached to the connection plate 17. Further, one end side (the end on the right side in the drawing) 15b of the cylindrical body 15 is fixed to the bearing 14, and the other end 10b side of the ball screw 10 is inserted inside.

Then, in the inertial mass damper 6B configured as described above, when an earthquake or the like occurs and vibrational energy acts on the bridge 1 and relative displacement occurs in the lower structure 1B and the upper structure 1A (when input), The ball screw 10 advances and retracts in the direction of the axis O2 according to the displacement difference, and the ball nut 11 supported by the inner ring 14b of the bearing 14 rotates and the rotary weight 12 rotates. At this time, the ball screw 10 advances and retracts in the direction of the axis O2, and is inserted into and released from the inner hole of the cylindrical body 15.
As a result, an inertial mass effect that is several thousand times as large as the actual mass of the rotary weight 12 is obtained, and the response displacement is significantly reduced as compared with the case where a conventional damping device such as an oil damper is installed.

  In addition, since the inertial mass damper 6B rotates the rotary weight 12 with relative displacement acting on both ends to obtain an inertial mass effect as large as several thousand times of mass mass, reaction force proportional to the acting relative acceleration is can get. Due to such a mechanism, there is no static rigidity, and expansion and contraction (low speed) due to the temperature of the upper structure 1A of the bridge 1 is followed with almost no reaction force.

Here, FIG. 1 (b) shows a vibration analysis model of the connection vibration control structure A for the bridge of this embodiment. In this FIG. 1 (b), the mass of one adjacent first bridge girder part 2 is m ₁ , the mass of the other second bridge girder part 3 is m ₂ , and one of the first bridge girder parts 2 is a bridge leg of lower structure 1B. The horizontal rigidity of one of the first bearings 5A to be supported at 7 is k ₁ , and the horizontal rigidity of the other second bearing 5B is k ₂ .
Further, the horizontal rigidity of the bridge portion 7 is k ₀ , and the mass when the vibration characteristics of the bridge portion 7 are modeled into an equivalent one mass point system is m ₀ . Furthermore, and the damping coefficient of the damping damper 4 installed in connection between the adjacent bridge girder portion 2 adjacent the C _d.

In the vibration analysis model shown in FIG. 1 (b), the rigidity k ₀ of the bridge base 7 is sufficiently large (k ₁ , k ₂ << k) in the general bridge as compared with the rigidity k ₁ and k ₂ of the rubber bearing. ₀ ) In setting based on frequency transfer function, consider k ₀ as a rigid body and consider that seismic motion is input to the lower part of the bearing (the top of the bridge pier). That is, it is considered that the acceleration excitation x ₀₁ (····) = x ₀ (···) acts on the mass m ₀ . More specifically, in the frequency transfer function of the first bridge girder 2 and the second bridge girder 3, the damper load is set so as to minimize the peak value of the response magnification.
After confirming the change of the frequency transfer function by the presence or absence of the damping damper 4 of the optimum specifications set in this way, the vibration control effect is grasped and evaluated by time history response analysis.

The acceleration response magnifications of the mass points m ₁ and m ₂ are determined as follows. Here, absolute displacement x _{i of} each mass point, rigidity k _i of each support 5A, 5B, inertia mass Ψ _d of inertia mass damper 6B provided in parallel with second support 5B, spring member 6A provided in parallel with first support 5A the spring stiffness _{k a} of the damping coefficient _{C d} of the damping damper 4 for connecting the bridge girder portions 2 and 3, when the input acceleration and _{x 0} (· · above), (1), (2), ( 3) Formula and (4) Formula are obtained.

Then, (4) can be obtained (5) to be denoted by - (7), acceleration response magnification of the mass point _m 1, _{m 2} is (9), and as (10) an absolute value of the expression .

  After confirming the change of the transfer function according to the presence or absence of the damper of the optimum specifications set in this way, the damping effect is grasped by time history response analysis. In the present analysis, the structural damping of the bridge leg 7 to be the lower structure 1B is set to 5% with respect to the primary natural frequency, and the damping of the bearings 5A and 5B made of a rubber bearing is neglected.

  Here, the simulation results (trial design) of the seismic performance of the bridge 1 when the connection vibration control structure A for the bridge of the present embodiment is provided will be described using FIGS. 1A and 1B and the like.

In this simulation, the simulation is performed on the three cases, Case 2 of the present embodiment in which the damping damper (oil damper) 4 is installed between the non-damping Case 1 without the damping damper 4 and the beam-girder. The simulation results of were compared.
Concretely, since Case1 is non-vibration control, the natural frequency of both bridge girder parts 2 and 3 becomes the same, shakes together, and it is a thing of the structure where a damping device does not work. Case2 (referred damping a) is a first bridge beam 2 by adding the spring stiffness k _a spring member 6A, digit - is installed vibration damping structure of the oil damper C _d is a damping damper 4 between the digits . Case3 (referred damping b) it is the first bridge beam 2 by adding the spring stiffness _{k a} of the spring member 6A, the second bridge beam 3 Add the inertial mass damper [psi, digits - oil between digits damper _{C d} It is a vibration control structure in which

Case 1 is a case where the natural frequency of both bridge girder parts 2 and 3 is the same and does not become connection damping, and represents the structure before performing damping reinforcement. In Case 1, responses of the mass points m ₁ and m ₂ are the same.
In both cases 2 and 3, viscous damping is provided only at the connection part, and springs or inertia masses are provided in parallel with the bearings 5A and 5B to make the natural frequencies of the bridge girder parts 2 and 3 deviate from each other.

Moreover, the span of 20 m of spans of one adjacent 1st bridge girder part 2 and the span of the other 2nd bridge girder part 3 modeled the bridge 1 between 3 spans of 30 m. As shown in Table 1, the specifications of this bridge 1 are bridge girder mass m ₁ = 1052 ton with 20 m span, bridge mass m ₂ = 1578 t for 30 m span, and bearing rigidity k ₁ = k ₂ = 73.5 kN / The bearing stiffness for receiving both bridge girder parts 2 and 3 is assumed to be the same, and in time history response analysis, it is modeled as a bridge base mass m ₀ = 319 ton and a substructure rigidity k ₀ = 954 kN / mm.
Table 1 shows the vibration specification in each case.

Next, the result of having examined the difference in the vibrational characteristic by the presence or absence (Case1, Case2, Case3) of the damping damper 4 using a frequency transfer function in a frequency domain is demonstrated.
The structural attenuation h is h = 0.01.

3 and 4 add the ratio of the digit acceleration (x ₂ (“••••••”), x ₁ (“•••••”)) to the ground surface acceleration x ₀ (“•••••••••••••••••••” It is the result shown as a response magnification for each vibration frequency. Here, FIG. 3 is the response of the mass point m _1, FIG. 4 shows the response of the mass point m _2.
In addition, excitation frequency ratio ξ is a ratio of excitation angular frequency ω = 2πf (f is excitation frequency) to ω ₀ = √ (k ₂ / m ₂ ), and X _i (above ") Is the Fourier transform of the acceleration x _i (" .. "above). 3 and 4, the horizontal axis input frequency (vibration frequency _{ratio) ξ (ω / ω 0)} , the response magnification vertical axis (X 2 ₍ "..." above) / X 0 _(above “••”, X ₁ (“••” above) / X ₀ (“••” above) are shown.

From FIGS. 3 and 4, it is confirmed that the response magnification at resonance is significantly reduced by performing the damping (Cases 2 and 3) of the present embodiment. Further, the reaction force of the lower structure (substructure) is approximately proportional to the acceleration of the bridge girder portions 2 and 3, and the reaction force of the lower structure is similarly reduced.
In particular, in Case 3 in which the inertial mass damper 6B and the spring member 6A were used in combination, it was confirmed that the maximum response magnification was extremely small at 2.5 or less, and the characteristics hardly resonated. Furthermore, in the high frequency range (the range where the vibration frequency ratio 横 in the horizontal axis is large), the response magnification is sufficiently smaller than 1 and the acceleration reduction effect in the high frequency range exceeding the natural frequency is You can expect. And since mass points m ₁ and m ₂ in Case ₁ have the same natural frequency, the response magnification is also the same.

5 and 6, each unit displacement for the ground surface displacement _{x 0 (x 1, x 2} , relative displacement _| x 2 _-x 1 _|) is the result of the ratio of the response factor.
From FIG. 5 and FIG. 6, the response magnification in the resonance region is greatly reduced by damping (Cases 2 and 3), and both displacements are suppressed (both bridge girder displacement = displacement of mass points m ₁ and m ₂ , both It is confirmed that the bearing displacement of In particular, in Case 3, as in the case of the above-mentioned acceleration, it was confirmed that the maximum response magnification was extremely small at 2.5 or less, and the characteristics hardly resonated.

  Further, the relative displacement is also suppressed to the same extent as the response displacement, so the possibility of the bridge girder parts 2 and 3 colliding with each other at the time of an earthquake or of falling apart due to excessive separation is reduced. In Case 3, since the maximum response magnification of relative displacement is as small as about 30% of Case 2 and the response magnification outside of the resonance region is 1 or less, there is little possibility that excessive relative displacement will occur regardless of earthquake motion Become.

FIG. 7 is an enlarged view of the vertical axis (response magnification) of FIGS. 5 and 6 by 5 times, and the bearing 5A of Case 3 is illustrated to compare the same as FIGS. 5 and 6 with relative displacement. ing. The vertical axis shown in FIG. 7 is | (X ₁ −X ₂ ) / X ₀ | for relative displacement, | (X ₁ −X ₀ ) / X ₀ | for the first bearing 5B, and for the second bearing 5B. , | (X ₂ −X ₀ ) / X ₀ |.

  Next, the result of having examined the difference of the response by the existence (Case1, Case2, Case3) of damping damper 4 using time history analysis is explained.

Here, Japan Road Association: II-II-3 seismic waves (maximum acceleration 736 gal) corresponding to the two grounds with level 2 earthquake motion shown in the road bridge specification, and the response results in time history waveform Compared.
The waveform of this input earthquake motion is as shown in FIG.

9 and 10 show the acceleration of one bridge girder (mass point 1) 2 in Case 2 and 3 respectively, and FIGS. 11 and 12 show the acceleration of the other bridge girder (mass point 2) 3 in Case 2 and 3 respectively. There is.
As shown in FIG. 9 to FIG. 12, in Case 1 where both vibration characteristics are equal, there is no relative displacement in the connecting part because the swinging of both of the bridge girder parts 2 and 3 is the same and there is no effect of connection damping Can be confirmed. Therefore, the response accelerations of the mass points 1 and 2 are the same.

In Case 2 in which the spring member 6A is added in parallel to the bearing 5A, the maximum response acceleration is hardly reduced by damping, but damping by the damping damper 4 is applied to the connection portion connecting adjacent bridge girder parts 2 and 3 to each other. It has been confirmed that the duration of the big shaking is significantly reduced.
On the other hand, in Case 3 where vibration damping devices are added not only at the connection part but also in parallel with the bearings 5A and 5B, the maximum response acceleration is greatly reduced to 1/2 to 1/3, and the sway converges more rapidly than Case 2. Recognize. In particular, it was confirmed that the acceleration of the second bridge girder portion 3 (mass point 2) in which the inertia mass damper 6B was installed was greatly reduced.

  Also, when comparing the acceleration response waveforms of the mass points 1 and 2, in Case 2 the peaks are almost at the same time, but in Case 3 the occurrence time of the peaks is deviated and Considering that it acts as a seismic force, Case 3 can be said to have a high damping effect to reduce the stress of the bridge 7.

Next, FIGS. 13 and 14 show the displacement of one first bearing (mass point 1) 5A in Case 2 and 3 respectively, and FIGS. 15 and 16 show the other second bearing (mass point 2) 5B in Case 2 and 3 respectively. Shows the displacement of the
As shown in FIG. 13 to FIG. 16, in Case 1 where both vibration characteristics are equal, there is no relative displacement in the connecting part because the swinging of both of the bridge girder parts 2 and 3 is the same, and there is no effect of connection damping. Can be confirmed. Therefore, the bearing response displacements of the mass points 1 and 2 are the same.

In Case 2 in which the spring member 6A is added in parallel to the support 5A, the maximum response displacement of the mass point 2 with a large mass is hardly reduced by damping, but the damping damper 4 is connected to the connecting portion connecting adjacent bridge girder parts 2 and 3 to each other. It was confirmed that the duration of the large shaking was significantly reduced by applying the damping due to.
On the other hand, in Case 3 where vibration damping devices are added not only at the connection part but also in parallel with the bearings 5A and 5B, the maximum response displacement is greatly reduced to 1/2 to 1/3, and the sway converges more rapidly than Case 2. Recognize. And it was confirmed that the response displacement of the 1st bridge girder part 2 (mass point 1) with high natural frequency which added spring member 6A parallel to bearing 5A, 5B is reduced sharply.

  Also, comparing the displacement response waveforms of the mass points 1 and 2, in Case 2 the peaks are at almost the same time, but in Case 3 the occurrence time of the peaks is shifted, and bridge girder parts 2 and 3 due to the addition of inertial mass damper 6B. This is considered to be because the difference in the vibration characteristics between them has become large.

FIG. 17 shows the relative displacement between digits in Cases 2 and 3.
As shown in FIG. 17, it was confirmed that the relative displacement between the girders was 200 to 300 mm, and the convergence of the shaking was also quick.
The reaction force of the vibration control damper 4 is 2900 kN in Case 2 and 600 kN per unit is sufficient if five oil dampers are arranged in parallel, which is a range sufficient for products used for seismic isolation. In addition, it is 5500kN in Case 3 and 800kN per unit is sufficient if seven oil dampers are arranged in parallel, which is a range that can be sufficiently coped with by products used for seismic isolation.

  On the other hand, the reaction force of the inertia mass damper 6B in Case 3 is 16300 kN, and if a total of 18 units are installed at both ends of two of the three-gauge beams, 910 kN per unit is sufficient, and the reaction force of the spring member 6A Is 4710 kN, and if a total of 12 units are installed at the two ends of the girder having three diameters, a total of only 400 kN can be used per unit, which is a range that can be sufficiently coped with by the current products.

Next, FIGS. 18 and 19 show the shear force N with respect to the time (sec) of the bridge 7 in Case 2 and 3. FIG.
As shown in FIG. 18 and FIG. 19, it was confirmed that in Case 2 the maximum response value hardly changes due to the damping in Case 2, but the convergence of the shaking becomes faster.
On the other hand, in Case 3, it was confirmed that the maximum stress value was reduced to 40% due to vibration control, and that the convergence of shaking was even faster than in Case 2.

  Therefore, in the connection vibration control structure A for the bridge according to the present embodiment, the adjacent bridge girder portions 2 and 3 are connected by the vibration control damper 4, and the bridge girder portions 2 and 3 of the lower structure 1B and the upper structure 1A of the bridge 1 are connected. The vibration control device 6 (spring member 6A, inertia mass damper 6B) is additionally disposed in parallel with the obstacles 5A and 5B between them, so that vibration of the adjacent bridge girder parts 2 and 3 is generated. Even if the characteristics are the same, both vibration characteristics (natural frequency) can be changed, and a large response reduction effect can be obtained. Therefore, it solves the problem that the vibration control effect can not be obtained when the vibration characteristics of both adjacent bridge girder portions 2 and 3 are the same as in the conventional case, as in the case of the vibration control by the vibration control damper 4 alone. be able to.

  In addition, when the spring member 6A is added as the vibration control device 6 and both vibration characteristics are changed, the maximum response acceleration and the maximum response displacement of the added bridge girder are reduced, but the spring member 6A is added The response of the non-doing side (the side of the mass multiplied by the spring stiffness) is not significantly reduced. Further, the stress generated in the bridge leg portion 7 is smaller than in the case where both the spring member 6A and the inertial mass damper 6B are provided, but can be obtained as a damping effect. In either case, there is an advantage that the convergence of the swaying becomes faster due to the vibration control.

  Further, in the present embodiment, as the vibration damping device, in addition to the spring member 6A, an inertial mass damper 6B is added, that is, when both of the vibration characteristics are changed by using both the spring member 6A and the inertial mass damper 6B. Both maximum response accelerations and maximum response displacements are greatly reduced. In addition, the stress generated in the bridge pier can be greatly reduced, and the shear force acting on the foundation can be reduced as well. In any case, the convergence of the shaking is faster than in Case 2 above (when only the spring member 6A is added).

  Moreover, since it is not necessary to exchange bearing part 5A, 5B, it is only adding a damping mechanism, and it can use bridge 1 continuously also during construction.

  In addition, since the damping damper 4 is provided so as to connect the adjacent bridge girder parts 2 and 3 and the damping device 6 is arranged relatively in parallel to the bearing 5, it is a relatively simple operation. It is not required and can be applied not only to new construction but also to damping improvement of the existing bridge 1.

  As mentioned above, although one embodiment of the connection damping structure with respect to the bridge concerning this invention and the setting method of the connection damping structure with respect to the bridge was described, this invention is not limited to said embodiment, The meaning is given. It can change suitably in the range which does not deviate.

1 Bridge 1A Upper structure 1B Lower structure 2 One bridge girder part (bridge girder)
3 The other second bridge girder (bridge girder)
4 Damping damper 5, 5A, 5B Bearing part 6 Damping device 6A Spring member 6B Inertia mass damper 7 Abutment part A Connection damping structure to bridge O1 Bridge shaft

Claims (2)

A damping damper is installed by connecting one end side to one adjacent first bridge girder part and the other end side to the other second bridge girder part,
A plurality of bearings are installed between each of the bridge girder parts and the lower structure, and a damping device is installed so as to be arranged in parallel with at least one of the bearings,
A spring member or an inertial mass damper is provided as the damping device, and a damper factor is set so that the peak value of the response magnification is minimized in the frequency transfer function of the first bridge girder and the second bridge girder. Vibration control structure for bridges that is characterized by It is a setting method of the connection vibration control structure with respect to the bridge of Claim 1, Comprising:
In the case where the natural frequency of the first bridge girder is larger than the natural frequency of the second bridge girder,
A configuration in which the inertia mass damper is disposed in parallel with only the bearing on the second bridge girder side;
The spring member is disposed in parallel with only the bearing on the first bridge girder side,
The inertial mass damper is disposed in parallel with only the support on the second bridge girder side, and the spring member is disposed in parallel with only the support on the first bridge girder side.
A method of setting a connection vibration control structure for a bridge, wherein any one of the two is selectively provided.

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