JP2017020795A - Bridge kinetic response evaluation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bridge kinetic response evaluation method capable of performing an evaluation of a kinetic response/health of a bridge by acquiring an impact coefficient of the bridge without performing a deflection measurement operation by using an index based on a vertical acceleration response of a vehicle by paying an attention to a vehicle acceleration speed response of a train travelling on the bridge.SOLUTION: An acceleration speed meter for measuring a vertical acceleration speed is provided on all vehicles of a train, respectively and measures the vertical acceleration of each vehicle at the travelling time. Measurement data of the acceleration meter at the time of passing the bridge is extracted, and an individual vehicle amplification rate is calculated by dividing a feature amount of the waveform of the vertical acceleration speed measured by the acceleration speed meters of all vehicles by the feature amount of the vertical acceleration speed measured by an arbitrary reference vehicle in front of a traveling direction. The maximum value is extracted from among the individual vehicle amplification rates of all vehicles so as to calculate an acceleration speed amplification coefficient, and an impact coefficient of the bridge is calculated by applying the acceleration speed amplification coefficient to the relationship between the impact coefficient and the acceleration amplification coefficient of the bridge.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for evaluating a dynamic response of a railway bridge, and more particularly to a method for determining an impact coefficient (dynamic response component) of a bridge using a vehicle vertical acceleration response of a traveling train when passing through the bridge.

  In railway bridges such as high-speed railway bridges and viaducts, as shown in FIG. 9, resonance may occur due to periodic excitation caused by the regular axle arrangement of the traveling train, and a large dynamic response may occur. .

Such a large dynamic response generated during train travel has been reflected in the design as an impact coefficient.
On the other hand, the train traveling speed has increased dramatically, and because the PRC structure (prestressed concrete structure) has been adopted for the majority of railway bridges and low-stiffness girders have become popular, the formulas used for design are not applicable. There are many cases that become, and on-site measurement has confirmed that the resonance of the bridge when traveling by train is higher than before. It has been confirmed that a large response is excited by resonance even at a traveling speed of 200 km / h due to the reduction in rigidity of the girders.

  In addition, because high-speed railway bridges have a deflection limit during train travel, if dynamic response components are greatly excited by resonance during train travel, this is an important index for evaluating the dynamic response. The impact coefficient is used as Furthermore, the impact coefficient is also an important indicator in maintenance management because it is closely related to deterioration phenomena such as cracks in railway bridges.

  Conventionally, when evaluating the impact coefficient / dynamic response of a railway bridge, a ring displacement meter, video measurement, U Doppler (non-contact vibration measurement system for structures with built-in laser Doppler velocimeter), etc. are used. The vertical displacement of the bridge when passing through the train is measured on the bridge side (ground side) (deflection measurement), and the impact coefficient is obtained using this measurement result (see, for example, Patent Document 1).

JP 2012-233758 A

  However, in the conventional bridge dynamic response evaluation method described above, it is necessary to perform one deflection measurement on each bridge side (on the ground side) for each bridge. For this reason, structural performance (such as the degree of deterioration) may vary greatly due to construction and shared environments, so it is desirable to implement it on all railway bridges that make up the longest possible route. Carrying out all railway bridges on a long line requires a lot of labor and is difficult both in terms of human and time.

  Even if it is implemented for a typical railway bridge, there are cases where deflection measurement itself cannot be performed when it is built on national roads, railways, rivers, etc., or at places where wind is always strong. .

  In view of the above circumstances, the present invention pays attention to the vehicle acceleration response of a train traveling on a bridge, and by using an index based on the vertical acceleration response of the vehicle, the impact coefficient of the bridge is obtained without performing a deflection measurement work. It is an object of the present invention to provide a bridge dynamic response evaluation method that enables dynamic response evaluation / bridge soundness evaluation.

  In order to achieve the above object, the present invention provides the following means.

  The bridge dynamic response evaluation method according to the present invention includes a vehicle acceleration measuring step in which an accelerometer for measuring vertical acceleration is provided for all vehicles of a train, and the vertical acceleration of each vehicle during traveling is measured. The acceleration data extraction process at the time of passing the bridge that extracts the measurement data of the meter and the feature quantity of the waveform of the vertical acceleration measured by the accelerometer of all vehicles is the feature quantity of the vertical acceleration measured by any reference vehicle ahead in the running direction An individual vehicle amplification factor calculation step for calculating the individual vehicle amplification factor, an acceleration amplification factor calculation step for calculating an acceleration amplification factor by extracting a maximum value from the individual vehicle amplification factors of all vehicles, and a calculation in advance An impact coefficient calculating step of calculating the impact coefficient of the bridge by applying the acceleration amplification coefficient to the relationship between the impact coefficient of the bridge and the acceleration amplification coefficient.

  In the bridge dynamic response evaluation method according to the present invention, it is desirable that the vertical acceleration feature amount is at least one of a maximum value, a minimum value, and an RMS of an acceleration waveform when passing through the bridge.

  In the bridge dynamic response evaluation method of the present invention, the impact coefficient of the bridge can be obtained and evaluated simply and comprehensively from the response of the vehicle of the traveling train. That is, the impact coefficient of a huge number of bridges constituting a route can be easily grasped without measuring the deflection of each bridge.

  In addition, since the impact coefficient of the bridge can be easily and comprehensively determined from the response of the train train, it is possible to determine the bridge constructed on national roads, railways, rivers, etc. The impact coefficient can be obtained even for bridges where it is difficult to perform deflection measurement.

  Furthermore, when the train travels on a daily basis, it is also possible to track the change in impact coefficient with time.

  Therefore, according to the bridge dynamic response evaluation method of the present invention, extraction of weak points based on actual structural performance and selection of detailed measurement points become much easier, and investigation and management can be made more efficient. become.

It is a figure which shows the change at the time of the bridge | bridging maximum deflection | deviation generation | occurrence | production by the beating phenomenon accompanying train travel. It is a figure which shows the relationship between bridge deflection and vehicle acceleration. It is a figure which shows an example of arrangement | positioning of the accelerometer with respect to a traveling vehicle in the bridge dynamic response evaluation method which concerns on one Embodiment of this invention. It is a figure which shows the bridge dynamic response evaluation method which concerns on one Embodiment of this invention, and is a flowchart which shows the impact coefficient estimation method of a bridge using the acceleration of a traveling vehicle. It is a figure which shows an example of the relationship between the acceleration amplitude rate and impact coefficient in a bridge with span length of 10 m. It is a figure which shows the estimation precision of the estimation formula (3) based on an acceleration amplitude rate. It is a figure which shows an example of the relationship between the acceleration amplitude rate and impact coefficient in a bridge with span length of 45 m. It is a figure which shows the estimation precision of the estimation formula (4) based on an acceleration amplitude rate. It is a figure which shows an example of the resonance waveform of the railway bridge at the time of train travel.

  Hereinafter, a bridge dynamic response evaluation method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8.

  First, in a railway bridge, the greater the deflection of the bridge, the greater the acceleration of the vehicle. In addition, there is almost no dynamic response on the bridge when the train passes the top vehicle (only static response).

  Further, as shown in FIGS. 1 and 2, each vehicle 1a of the train 1 has two front and rear axes (two axes of the first bogie 1b at the front of each vehicle and two axes of the second bogie 1c at the rear), for a total of four axes. A total of 4 axles are concentrated on the connecting part of the front and rear vehicles for each of the front and rear vehicles, whereas the front and rear axles of the train 1 have two axles. become. For this reason, the dynamic response of the bridge when the first and last two axles of the train 1 pass is inevitably more than the dynamic response when the four axles of the connecting portion of the vehicle 1a pass. It becomes small (almost half).

  Also, as shown in FIGS. 1 and 2, when the train travels at the resonance speed, a larger dynamic response is excited when the vehicle is passing as the vehicle is behind. On the other hand, since a whirling phenomenon occurs when the train travels near the resonance speed, the larger the dynamic response is not necessarily excited when passing the vehicle, the greater the dynamic response is excited when passing the intermediate vehicle. Is done.

  In the bridge dynamic response evaluation method of the present embodiment, paying attention to the characteristics of the above-mentioned railway bridge, as shown in FIG. 3, on the first carriage 1b and / or on the second carriage 1c of all the vehicles 1a of the train 1. Is provided with an accelerometer 2 to measure the acceleration in the vertical direction when the train travels (vehicle acceleration measurement step). In addition, the traveling speed of the train is measured at any time.

  Note that the accelerometer 2 is not necessarily limited to being provided on the first carriage 1b and / or the second carriage 1c of each vehicle 1a. Also in this case, it is desirable to select the same location as the accelerometer installation position in each vehicle 1a so as to reduce errors caused by measurement locations and vehicle vibration as much as possible.

  And, as shown in FIG. 4, in the bridge dynamic response evaluation method of the present embodiment, based on the bridge data storing the traveling speed of the train 1, the span length, the starting kilometer, the terminal kilometer and the design impact coefficient, Measurement data of all accelerometers 2 when the train 1 is passing through the target bridge is extracted (acceleration data extraction process when passing through the bridge).

  Next, as shown in the following formula (1), the feature amount of the waveform of the vertical acceleration measured by the accelerometer 2 on the first carriage 1b and / or the second carriage 1c of all the vehicles 1a A value (individual vehicle gain Cai) divided by the feature amount of the vertical acceleration measured by any reference vehicle (for example, the second vehicle (second vehicle) 1a) is calculated (individual vehicle gain calculation step).

  As described above, the dynamic response of the bridge when the first and last two axles of the train 1 pass is more than the dynamic response when the four axles of the connecting portion of the vehicle 1a pass. Since it is inevitably small, that is, the amount of flexure of the bridge is smaller when the first vehicle 1st carriage 1b and the last vehicle 2nd carriage 1c pass through the bridge than when the other carriage passes, It is preferable to calculate a value obtained by dividing the feature amount of the vertical acceleration waveform of the removed vehicle 1a by the feature amount of the vertical acceleration measured by the reference vehicle 1a.

  Here, examples of the feature amount of the vertical acceleration of each vehicle 1a include the maximum value, the minimum value, and RMS (average amplitude) of the acceleration waveform when passing through the bridge.

  Next, the acceleration amplification coefficient Ca is calculated by extracting the maximum value from the individual vehicle amplification factors Cai of all the vehicles 1a by the following equation (2) (acceleration amplification coefficient calculation step). In equation (2), vec () means extracting a vector, and Max () means extracting a maximum value from a parenthesized vector.

  Next, by applying the acceleration amplification coefficient Ca calculated in Expression (2) to the relational expression between the impact coefficient and acceleration amplification coefficient obtained in advance, the bridge impact coefficient / impact coefficient estimated value ia (= (static + dynamic) Target deflection) / (static deflection) -1) is calculated (impact coefficient calculation step).

  Here, FIG. 5, FIG. 6 and the following expression (3) are the relationship between the impact coefficient and acceleration amplification coefficient of the bridge when the RMS is used as the feature amount of the vertical acceleration of the bridge with a span length of less than 40 m. , Shows the relational expression.

  7 and 8, the following equation (4) is the relationship between the impact coefficient and acceleration amplification coefficient of the bridge when the RMS is used as the feature amount of the vertical acceleration of the bridge having a span length of 40 m or more, Relational expressions are shown.

  As shown in these figures, Equation (3), which is an estimation formula for the impact coefficient ia of a bridge with a span length of less than 40 m, based on the actual measurement results of Shinkansen vehicles with 10-car trains and railway bridges, is vehicle / bridge It is confirmed that an impact coefficient of 0.7 or more can be estimated with an error of 30% or less by comparing with the numerical simulation result in consideration of the dynamic interaction.

  Equation (4), which is an estimation formula for the impact coefficient ia of a bridge with a span length of 40 m or more, is roughly equivalent to an impact coefficient of 0.4 or more by comparison with the numerical simulation result considering the vehicle / bridge dynamic interaction. It has been confirmed that estimation is possible with an error of 15% or less.

  Further, in the bridge dynamic response evaluation method of the present embodiment, when a plurality of runs are performed and there are more vehicle acceleration waveforms, the process shown in FIG. 4 is sequentially performed and the estimated impact is stored in the bridge database. Accumulate coefficients.

  Furthermore, when there are a plurality of vehicle acceleration waveforms, the measurement date is added as information to be recorded in the bridge database. Further, the estimated impact coefficient, train speed, and bridge ID are stored in the bridge database.

  And the estimated impact coefficient of each bridge in the whole route is output (impact coefficient output process of object bridge). At this time, for example, the top number% of bridges with a large estimated impact coefficient, the top number% of bridges with a large estimated impact coefficient relative to the design impact coefficient, and the estimated impact coefficient in a bridge of the same structural type or the same span length is large. By using a ranking format that focuses on indicators, such as the top several percent of bridges, it is possible to extract weak spots based on actual structural performance and select detailed measurement locations.

  Therefore, in the bridge dynamic response evaluation method of the present embodiment, the impact coefficient of the bridge can be easily and comprehensively determined and evaluated from the acceleration response of the vehicle 1a of the traveling train 1. That is, the impact coefficient of a huge number of bridges constituting a route can be easily grasped without measuring the deflection of each bridge.

  In addition, since the impact coefficient of the bridge can be obtained easily and comprehensively from the response of the vehicle 1a of the traveling train 1, the bridge constructed on a national road, railway, river, etc., or a place where wind is always strong It is possible to obtain the impact coefficient even for bridges where it is difficult to perform deflection measurement, such as bridges.

  Furthermore, when the traveling of the train 1 is carried out on a daily basis, it is also possible to track the change with time of the impact coefficient.

  Therefore, according to the bridge dynamic response evaluation method of this embodiment, extraction of weak points based on actual structural performance and selection of detailed measurement points become much easier, and the efficiency of investigation and management can be greatly improved. It becomes possible.

  Further, as in this embodiment, the accelerometer 2 is provided in all the vehicles 1a of the train 1, and the vertical acceleration of all the vehicles 1a is measured to calculate the impact coefficient of the bridge. The impact coefficient can be obtained with higher accuracy compared to the case where the accelerometer 2 is provided only in a specific vehicle such as a vehicle, and the impact coefficient is calculated by measuring the vertical acceleration.

  That is, when a train is traveling at a resonance speed, a larger dynamic response is excited when the vehicle is behind, whereas a whirling phenomenon occurs when a train is traveling near the resonance speed. As it is, a larger dynamic response is not always excited when passing, and a larger dynamic response is excited when passing an intermediate vehicle.

  On the other hand, even if it does not know which intermediate vehicle passes when a large dynamic response is excited, the accelerometer 2 is provided in all the vehicles 1a of the train 1, and the vertical acceleration of all the vehicles 1a is measured to measure the impact coefficient of the bridge. It is possible to calculate the impact coefficient with high accuracy.

  Furthermore, by equation (3), an impact coefficient of 0.7 or more in a bridge with a span length of less than 40 m can be estimated with an error of about 30%. Moreover, even if it is less than 0.7, since it is not underestimated by 30% or more, a bridge having a large impact coefficient is not overlooked.

  Further, according to the equation (4), an impact coefficient of 0.4 or more in a bridge having a span length of 40 m or more can be estimated with an error of about 15%. Moreover, since it is not underestimated 15% or more even if it is less than 0.4, a bridge with a large impact coefficient is not overlooked.

  As mentioned above, although one Embodiment of the bridge dynamic response evaluation method of this embodiment of this embodiment concerning this invention was described, this invention is not limited to said one embodiment, and does not deviate from the meaning. The range can be changed as appropriate.

1 train 1a vehicle 1b first cart 1c second cart 2 accelerometer

Claims (2)

An accelerometer that measures the vertical acceleration of each vehicle in each train is provided, and a vehicle acceleration measurement process that measures the vertical acceleration of each vehicle during travel,
Acceleration data extraction process at the time of passing through the bridge for extracting measurement data of the accelerometer when passing through the bridge;
Individual vehicle amplification factor calculation step of calculating the individual vehicle amplification factor by dividing the feature amount of the waveform of vertical acceleration measured by the accelerometer of all vehicles by the feature amount of vertical acceleration measured by any reference vehicle ahead in the running direction When,
An acceleration amplification coefficient calculation step of calculating an acceleration amplification coefficient by extracting a maximum value from the individual vehicle amplification factors of all vehicles;
A bridge dynamic response evaluation method comprising: an impact coefficient calculation step of calculating an impact coefficient of a bridge by applying the acceleration amplification coefficient to a relationship between an impact coefficient and an acceleration amplification coefficient obtained in advance. In the bridge dynamic response evaluation method according to claim 1,
The bridge dynamic response evaluation method, wherein the feature amount of the vertical acceleration is at least one of a maximum value, a minimum value, and an RMS of an acceleration waveform when passing through the bridge.

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