Bridge support stress state monitoring system and method based on piezoelectric impedance

Abstract

The invention discloses a bridge support stress state monitoring system and method based on piezoelectric impedance, and relates to the technical field of bridge structure monitoring. Wherein the four piezoelectric ceramic sensor arrays are respectively pre-buried at each bridge support and are used for monitoring the stress state of the bridge support in real time; the wireless impedance analyzer is arranged at a bridge cover beam and is used for testing the electrical admittance of a bridge support and transmitting the electrical admittance data to the remote monitoring terminal; and the remote monitoring terminal is used for evaluating the stress state of the bridge support according to the electrical admittance data. Whether the stress state of the bridge support is changed or not can be judged, damage of support disengaging, serious bias pressure and support overturning is prevented, and the bridge support stress detection device has the advantages of being high in detection efficiency, high in accuracy, low in cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge structure monitoring, and more particularly to a bridge support stress state monitoring system and method based on piezoresistive impedance. Background Art

[0002] In bridge engineering, bearings are key components that connect bridge piers and bridge beams. They have important functions such as transferring loads, alleviating vibrations and deformations. During the operation of bridge structures, bearings will be affected by factors such as environmental corrosion, long-term dynamic and static load effects, material aging, and earthquake disasters, which may lead to serious bearing bias, bearing detachment, or bearing flipping. The stress state of bearings is closely related to the safe operation of bridges.

[0003] Damage or destruction of bridge bearings is one of the main defects of bridges in service in my country. When bearings are damaged, the stress distribution of the bridge beam changes, which may cause the overall imbalance of the bridge and pose a serious threat to the overall safety of the bridge. In order to ensure the safe operation of bridges, prevent safety accidents and prolong the service life of bridge structures, bridge bearings need to be inspected regularly. Due to the hidden environment of bearings and the large number of bridges in my country, the currently used manual visual inspection method is difficult to effectively judge the stress state of bearings.

[0004] The piezoresistive impedance method (Electro-Mechanical Impedance, EMI) based on piezoelectric ceramic transducer (PZT) is one of the bridge structure detection technologies. This technology has the characteristics of fast detection speed and is sensitive to the force changes and damage of the structure. Piezoelectric ceramics have positive and negative piezoelectric effects, which can realize the mutual conversion of mechanical energy and electrical energy. Therefore, piezoelectric ceramics can be used as drivers and sensors at the same time. Piezoelectric ceramics are small in size and can be easily pasted or buried in the structure for detection.

[0005] Therefore, on this basis, how to provide a bridge bearing stress status monitoring system and method that is convenient to monitor, low-cost, effective and accurate, and provides early warning, and realize the monitoring of the safety status of the bridge is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention provides a bridge bearing stress state monitoring system and method based on piezoresistive impedance, which solves the problems existing in the background technology.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A bridge bearing stress state monitoring system based on piezoresistive impedance, comprising: four piezoelectric ceramic sensor arrays, a wireless impedance analyzer, and a remote monitoring terminal;

[0009] Four piezoelectric ceramic sensor arrays are pre-buried in each bridge support to monitor the stress state of the bridge support in real time;

[0010] The wireless impedance analyzer is set at the bridge cap beam to test the electrical admittance of the bridge support and transmit the electrical admittance data to the remote monitoring terminal;

[0011] Remote monitoring terminal, used to evaluate the stress state of bridge bearings based on electrical admittance data.

[0012] In the above monitoring system, optionally, the piezoelectric ceramic sensor array includes a plurality of piezoelectric ceramic sensors, each of which is arranged at a steel plate layer of a bridge support.

[0013] In the above monitoring system, optionally, each bridge support is provided with four piezoelectric ceramic sensors, and connected to the wireless impedance analyzer through wires.

[0014] In the above monitoring system, optionally, the piezoelectric ceramic sensor uses a lead-based piezoelectric ceramic with lead zirconate titanate as the core.

[0015] In the above monitoring system, optionally, the wireless impedance analyzer includes an electrical signal excitation module, an impedance acquisition module and a data transmission module connected in sequence;

[0016] An electrical signal excitation module, used to excite the piezoelectric ceramic sensor array through alternating current;

[0017] Impedance acquisition module, used to collect the admittance signal generated by the piezoelectric ceramic sensor array;

[0018] The data transmission module is used to transmit the electrical admittance signal to the remote monitoring terminal via wireless data.

[0019] In the above monitoring system, optionally, the remote monitoring terminal includes a curve fitting module, a data processing module and a force analysis module connected in sequence;

[0020] A curve fitting module, used for fitting the received electrical admittance data into an impedance spectrum diagram;

[0021] A data processing module, used for obtaining a corresponding RMSD test value according to the impedance spectrum diagram;

[0022] The stress analysis module is used to compare the RMSD test value with the standard value under normal stress state to determine the stress state of the bridge bearing.

[0023] In the above monitoring system, optionally, the stress state of the bridge bearing includes: bearing empty, bearing under-pressure, bearing over-pressure, and bearing normal.

[0024] A bridge bearing stress state monitoring method based on piezoresistive impedance, applied to any of the above-mentioned bridge bearing stress state monitoring systems based on piezoresistive impedance, comprises the following steps:

[0025] S1. Before installing the bridge bearing, measure the electrical admittance data of the bridge bearing and record the corresponding impedance spectrum;

[0026] S2. Install bridge bearings. When each bridge bearing is in a uniform stress state, use a wireless impedance analyzer to apply AC excitation to the piezoelectric ceramic sensor array. After receiving the AC excitation, the piezoelectric ceramic sensor array vibrates and drives the entire bridge bearing to resonate. The electrical admittance data is measured and wirelessly transmitted to the remote monitoring terminal.

[0027] S3, the remote monitoring terminal generates an impedance spectrum diagram under load state according to the electrical admittance data measured by S2, calculates the RMSD test value under the corresponding load according to the impedance spectrum diagram recorded by S1 and the impedance spectrum diagram under load state, and records the RMSD value measured by the bridge bearing under uniform force state as the standard value;

[0028] S4. After the bridge is officially put into operation, the impedance changes of each bridge bearing shall be regularly monitored according to S2 and S3, and the RMSD test value shall be compared with the standard value; according to the difference between the RMSD test value and the standard value, the bridge bearings shall be classified into four different stress states, namely: bearing empty, bearing underpressure, bearing overpressure, and bearing normal.

[0029] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a bridge bearing stress state monitoring system and method based on piezoresistive impedance, which has the following beneficial effects:

[0030] The present invention adopts PZT piezoelectric ceramic sensors, which are lower in cost and longer in effective working time than the resistive sensors used in the existing intelligent supports. In addition, the monitoring system uses a wireless impedance analyzer to collect electrical admittance data, and fits the electrical admittance data into an impedance spectrum through the curve fitting module of the remote monitoring terminal, and then uses the data processing module to compare the RMSD test value (root mean square deviation) calculated according to the impedance spectrum with the standard value under normal stress state to judge the stress state of the support. Compared with the existing support monitoring technology, it can directly reflect the stress state of the support, making the monitoring of the support more accurate and intelligent. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 A schematic cross-sectional view of the arrangement of the piezoelectric ceramic sensor array provided by the present invention;

[0033] Figure 2 A schematic longitudinal section diagram of the arrangement of the piezoelectric ceramic sensor array provided by the present invention;

[0034] Figure 3 A schematic diagram of welding the piezoelectric ceramic sensor provided by the present invention;

[0035] Figure 4 A schematic diagram of the overall structure provided by the present invention;

[0036] Figure 5 A flow chart of the bridge bearing stress state monitoring method provided by the present invention;

[0037] Reference numerals:

[0038] 1- piezoelectric ceramic sensor, 2- steel plate layer, 3- wiring point, 4- copper sheet, 5- ceramic layer, 6- wireless impedance analyzer, 7- remote monitoring terminal. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Due to factors such as environmental corrosion, material aging, and dynamic load effects, the stress state of bridge supports changes, resulting in safety risks to the bridge structure. However, existing detection technologies have problems such as low detection efficiency, low accuracy, and high cost.

[0041] To this end, the embodiment of the present invention discloses a bridge bearing stress state monitoring system based on piezoresistive impedance, comprising: four piezoelectric ceramic sensor arrays, a wireless impedance analyzer 6, and a remote monitoring terminal 7;

[0042] Four piezoelectric ceramic sensor arrays are pre-buried in each bridge support to monitor the stress state of the bridge support in real time;

[0043] The wireless impedance analyzer 6 is arranged at the bridge cap beam, and is used to test the electrical admittance of the bridge support and transmit the electrical admittance data to the remote monitoring terminal 7;

[0044] The remote monitoring terminal 7 is used to evaluate the stress state of the bridge bearing based on the electrical admittance data.

[0045] Furthermore, the piezoelectric ceramic sensor array includes a plurality of piezoelectric ceramic sensors 1, each of which is arranged at a steel plate layer 2 of a bridge support, such as Figure 1 , Figure 2 shown.

[0046] Furthermore, each bridge support is provided with four piezoelectric ceramic sensors 1, and connected to the wireless impedance analyzer 6 through wires, and the welding diagram thereof is shown in FIG. Figure 3 As shown, 3 is a connection point, 4 is a copper sheet, and 5 is a ceramic layer.

[0047] Furthermore, the piezoelectric ceramic sensor 1 uses lead-based piezoelectric ceramics (PZT-5) with lead zirconate titanate as the core.

[0048] Furthermore, the wireless impedance analyzer 6 includes an electrical signal excitation module, an impedance acquisition module and a data transmission module connected in sequence, and its layout diagram is shown in FIG. Figure 4 As shown;

[0049] An electrical signal excitation module, used to excite the piezoelectric ceramic sensor array through 1V alternating current;

[0050] Impedance acquisition module, used to collect the admittance signal generated by the piezoelectric ceramic sensor array;

[0051] The data transmission module is used to transmit the electrical admittance signal to the remote monitoring terminal 7 via wireless data.

[0052] Further, the remote monitoring terminal 7 includes a curve fitting module, a data processing module and a force analysis module which are connected in sequence;

[0053] A curve fitting module, used for fitting the received electrical admittance data into an impedance spectrum diagram;

[0054] A data processing module, used for obtaining a corresponding RMSD test value according to the impedance spectrum diagram;

[0055] The stress analysis module is used to compare the RMSD test value with the standard value under normal stress state to determine the stress state of the bridge bearing.

[0056] Furthermore, the stress states of the bridge bearings include: bearing empty, bearing under-pressure, bearing over-pressure, and bearing normal.

[0057] This embodiment also discloses a bridge support stress state monitoring method based on piezoresistive impedance, which is applied to the bridge support stress state monitoring system based on piezoresistive impedance as described above. Figure 5 As shown, the following steps are included:

[0058] S1. Before installing the bridge bearing, measure the electrical admittance data of the bridge bearing and record the corresponding impedance spectrum for subsequent calculation of the RMSD value;

[0059] S2. Install bridge bearings. When each bridge bearing is in a uniform stress state, use the electrical signal excitation module of the wireless impedance analyzer 6 to apply AC excitation to the piezoelectric ceramic sensor array. After receiving the AC excitation, the piezoelectric ceramic sensor array vibrates due to the inverse piezoelectric effect and drives the entire bridge bearing to resonate. The resonance of the bearing causes the piezoelectric sensor to output an electrical signal due to the positive piezoelectric effect. The output electrical signal is represented by electrical admittance data. The measured electrical admittance data is wirelessly transmitted to the remote monitoring terminal 7 by the data transmission module of the wireless impedance analyzer 6;

[0060] S3, the curve fitting module of the remote monitoring terminal 7 generates an impedance spectrum under load state according to the electrical admittance data measured by S2, and the data processing module calculates the RMSD test value under the corresponding load according to the impedance spectrum recorded by S1 and the impedance spectrum under load state, and records the RMSD value measured by the bridge bearing under uniform stress state as the standard value, so as to facilitate the subsequent stress state evaluation;

[0061] S4. After the bridge is officially put into operation, the impedance changes of each bridge bearing shall be regularly monitored according to S2 and S3, and the RMSD test value shall be compared with the standard value; according to the difference between the RMSD test value and the standard value, the bridge bearings shall be classified into four different stress states, namely: bearing empty, bearing underpressure, bearing overpressure, and bearing normal.

[0062] Specifically, when the RMSD test value approaches zero, the bridge bearing is in a hollow state; when the RMSD test value is significantly smaller than the standard value, the bridge bearing is in an under-pressure state; when the RMSD test value is significantly larger than the standard value, the bridge bearing is in an over-pressure state; when the RMSD test value approaches the standard value, the stress state of the bridge bearing has not changed significantly and is in a normal stress state.

[0063] To sum up, the technical solution of this embodiment can be used to monitor the stress state of bridge bearings. By installing a piezoelectric ceramic sensor array in the bridge bearing, the impedance value of the bearing is monitored using a wireless impedance analyzer 6 and the data is transmitted to a remote monitoring terminal 7. The measured data is analyzed to determine the stress state of the bridge bearing, thereby achieving the effect of monitoring and early warning of the healthy operation status of the bearing and the bridge structure, avoiding the occurrence of safety accidents. It has the advantages of convenient monitoring, low cost, effective and accurate, and early warning.

[0064] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. As for the method disclosed in the embodiment, since it corresponds to the system disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0065] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bridge bearing stress state monitoring system based on piezoresistive impedance, characterized in that: include: Four piezoelectric ceramic sensor arrays, wireless impedance analyzer, remote monitoring terminal; Four piezoelectric ceramic sensor arrays are pre-buried in each bridge support to monitor the stress state of the bridge support in real time; The wireless impedance analyzer is set at the bridge cap beam to test the electrical admittance of the bridge support and transmit the electrical admittance data to the remote monitoring terminal; Remote monitoring terminal, used to evaluate the stress state of bridge bearings based on electrical admittance data.

2. A bridge bearing stress state monitoring system based on piezoresistive impedance according to claim 1, characterized in that: The piezoelectric ceramic sensor array includes a plurality of piezoelectric ceramic sensors, and each piezoelectric ceramic sensor is arranged at a steel plate layer of a bridge support.

3. A bridge bearing stress state monitoring system based on piezoresistive impedance according to claim 2, characterized in that: Each bridge support is equipped with four piezoelectric ceramic sensors, which are connected to the wireless impedance analyzer through wires.

4. The bridge support stress state monitoring system based on piezoresistive impedance according to claim 2 is characterized in that: The piezoelectric ceramic sensor uses lead-based piezoelectric ceramics with lead zirconate titanate as the core.

5. The bridge support stress state monitoring system based on piezoresistive impedance according to claim 1 is characterized in that: The wireless impedance analyzer includes an electrical signal excitation module, an impedance acquisition module and a data transmission module which are connected in sequence; An electrical signal excitation module, used to excite the piezoelectric ceramic sensor array through alternating current; Impedance acquisition module, used to collect the admittance signal generated by the piezoelectric ceramic sensor array; The data transmission module is used to transmit the electrical admittance signal to the remote monitoring terminal via wireless data.

6. The bridge support stress state monitoring system based on piezoresistive impedance according to claim 1 is characterized in that: The remote monitoring terminal includes a curve fitting module, a data processing module and a force analysis module which are connected in sequence; A curve fitting module, used for fitting the received electrical admittance data into an impedance spectrum diagram; A data processing module, used for obtaining a corresponding RMSD test value according to the impedance spectrum diagram; The stress analysis module is used to compare the RMSD test value with the standard value under normal stress state to determine the stress state of the bridge bearing.

7. The bridge support stress state monitoring system based on piezoresistive impedance according to claim 1 is characterized in that: The stress conditions of bridge bearings include: bearing empty, bearing under-pressure, bearing over-pressure, and bearing normal.

8. A method for monitoring the stress state of a bridge support based on piezoresistive impedance, applied to the system for monitoring the stress state of a bridge support based on piezoresistive impedance as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Before installing the bridge bearing, measure the electrical admittance data of the bridge bearing and record the corresponding impedance spectrum; S2. Install bridge bearings. When each bridge bearing is in a uniform stress state, use a wireless impedance analyzer to apply AC excitation to the piezoelectric ceramic sensor array. After receiving the AC excitation, the piezoelectric ceramic sensor array vibrates and drives the entire bridge bearing to resonate. The electrical admittance data is measured and wirelessly transmitted to the remote monitoring terminal. S3, the remote monitoring terminal generates an impedance spectrum diagram under load state according to the electrical admittance data measured by S2, calculates the RMSD test value under the corresponding load according to the impedance spectrum diagram recorded by S1 and the impedance spectrum diagram under load state, and records the RMSD value measured by the bridge bearing under uniform force state as the standard value; S4. After the bridge is officially put into operation, the impedance changes of each bridge bearing shall be regularly monitored according to S2 and S3, and the RMSD test value shall be compared with the standard value; according to the difference between the RMSD test value and the standard value, the bridge bearings shall be classified into four different stress states, namely: bearing empty, bearing underpressure, bearing overpressure, and bearing normal.

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