Multi-point steady-state excitation system and method for bridge load test

Abstract

The invention discloses a multi-point steady-state excitation system and method for a bridge load test, and relates to the technical field of bridge tests, and the multi-point steady-state excitation system comprises a main excitation device, a plurality of auxiliary excitation devices and a main controller; the main controller is configured to select a to-be-tested mode of a bridge girder; exciting the bridge girder at the maximum vibration mode of the to-be-tested mode at the frequency of the to-be-tested mode by using main excitation equipment, so that the bridge girder vibrates at a single frequency; exciting the bridge girder at a plurality of maximum vibration modes corresponding to the to-be-tested mode by using a plurality of auxiliary vibration excitation devices, and keeping a preset phase difference between the vibration of the inertial mass block of each auxiliary vibration excitation device and the vibration of the bridge girder at the position where the auxiliary vibration excitation device is located; and selecting the next to-be-tested mode of the bridge girder, and repeating the process of exciting the bridge girder to vibrate until the bridge load test is completed. The bridge can be excited to generate obvious single-frequency steady-state vibration, the purposes of static load test and dynamic load test are achieved at the same time, few excitation devices are needed, and the test result precision is high.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge tests, and particularly relates to a multi-point steady-state excitation system and method for bridge load tests. Background Art

[0002] At present, the number of newly built and operating cable-supported bridges with main spans above one kilometer is continuously increasing. The main span of the under-construction long-span cable-stayed bridge reaches 1208m, the main span of the cable-stayed suspension bridge reaches 1488m, and the main span of the suspension bridge reaches 2300m. These bridges cost huge amounts to build and are important hub projects for each transportation line. The accurate assessment of their performance is of great importance.

[0003] The performance evaluation during the completion acceptance or use process of a bridge generally adopts the method of load tests, including static load tests and dynamic load tests. The bridge static load test is to measure the stress and strain and structural deformation of each main control section of the bridge under static load, so as to determine whether the actual working performance of the structure conforms to the design expectation value. Its loading condition is generally that the maximum load acts on the most unfavorable position of the bridge. The main means is to simulate the traffic load during the normal operation of the bridge by loading heavy vehicles. Taking a large-span highway suspension bridge with a double-deck bridge deck as an example, assuming 12 lanes, if a static load test is carried out, more than 400 heavy vehicles (about 30t) need to be arranged. The vehicle deployment is difficult, and the interference to the surrounding traffic is large. Once a problem occurs, it may affect the structural safety of the approach bridges and ramps on both sides. Therefore, for super-large-span bridges, the traditional static load test requires a large number of loading vehicles, high implementation difficulty, long time consumption, and high economic cost. There is an urgent need to find a more scientific method to replace the function of the traditional static load test.

[0004] Traditional dynamic load tests are mainly used to test parameters such as the frequency, vibration mode, and damping ratio of bridges. The excitation method can be determined according to the structural characteristics, test accuracy requirements, convenience, and actual site conditions. It is advisable to adopt the ambient random excitation method, the driving excitation method, and the vehicle jumping excitation method, and the shaker excitation method or other excitation methods can also be used. For large-span bridges, the excitation ability input by heavy vehicles is very limited. The signal-to-noise ratio of the bridge dynamic response signal is extremely low, the modal components are complex, and the modal order is uncontrollable. Therefore, the measured frequency, vibration mode, and damping ratio are limited. Especially for the damping ratio, due to the low signal-to-noise ratio of the bridge vibration response, the accuracy of the identified damping ratio is poor, and the dispersion of multiple measurements is high. Summary of the Invention

[0005] Embodiments of the present invention provide a multi-point steady-state excitation system and method for bridge load tests to solve the technical problems in the related art that the existing bridge load tests adopt traditional static load tests and dynamic load tests, which require a large number of loading vehicles, long time consumption, high cost, and low accuracy of test results.

[0006] In a first aspect, a multi-point steady-state excitation system for bridge load tests is provided, including: a main excitation device, a plurality of auxiliary excitation devices, and a main controller; The main controller is connected to the main excitation device and the plurality of auxiliary excitation devices, and is configured to: Select a to-be-tested mode of the bridge main girder; Use the main excitation device to excite the bridge main girder at a maximum vibration mode of the to-be-tested mode at the frequency of the to-be-tested mode, so that the bridge main girder exhibits single-frequency vibration; Then use the plurality of auxiliary excitation devices to excite the bridge main girder at a plurality of maximum vibration modes corresponding to the to-be-tested mode, and maintain a preset phase difference between the vibration of the inertial mass block of each auxiliary excitation device and the vibration of the bridge main girder at its location, so that the bridge main girder enters single-frequency steady-state vibration; Then select the next to-be-tested mode of the bridge main girder, and repeat the process of using the main excitation device and the plurality of auxiliary excitation devices to excite the bridge main girder to vibrate until the bridge load test is completed.

[0007] In some embodiments, the main excitation device includes a tractor, hydraulic legs provided at the lower end of the tractor, and a control cabinet, a power supply, and an excitation module provided on the tractor. The excitation module includes a box body, an actuator, an inertial mass block, and a spring.

[0008] In some embodiments, the plurality of auxiliary excitation devices have the same configuration as the main excitation device.

[0009] In some embodiments, the step of then using the plurality of auxiliary excitation devices to excite the bridge main girder at a plurality of maximum vibration modes corresponding to the to-be-tested mode, and maintaining a preset phase difference between the vibration of the inertial mass block of each auxiliary excitation device and the vibration of the bridge main girder at its location, so that the bridge main girder enters single-frequency steady-state vibration, includes: Obtain the first vibration parameter of the inertial mass block of any auxiliary excitation device and the second vibration parameter at the contact position between it and the bridge main girder; Judge whether the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference; If so, maintain the working parameters of the actuator of the auxiliary excitation device; if not, adjust the working parameters of the actuator of the auxiliary excitation device until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

[0010] In some embodiments, vibration sensors are provided on the inertial mass blocks of the main excitation device and the plurality of auxiliary excitation devices, and at the contact positions between the main excitation device and the plurality of auxiliary excitation devices and the bridge main girder.

[0011] In some embodiments, the vibration sensor is an ultrasonic vibration sensor, a magnetoelectric vibration sensor or a piezoelectric vibration sensor.

[0012] In some embodiments, before selecting a to-be-tested mode of the bridge main girder, it includes: Establish a finite element model of the bridge, and perform dynamic characteristic analysis according to the finite element model of the bridge to obtain multiple to-be-tested modes of the bridge main girder.

[0013] In a second aspect, a multi-point steady-state excitation method for bridge load test is provided, including the following steps: Step S10, select a to-be-tested mode of the bridge main girder; Step S20, use the main excitation equipment to excite the bridge main girder at a maximum vibration mode of the to-be-tested mode at the frequency of the to-be-tested mode, so that the bridge main girder has a single-frequency vibration; Step S30, then use multiple auxiliary excitation equipment to excite the bridge main girder at multiple maximum vibration modes corresponding to the to-be-tested mode, and keep a preset phase difference between the vibration of the inertial mass block of each auxiliary excitation equipment and the vibration of the bridge main girder at its position, so that the bridge main girder enters a single-frequency steady-state vibration; Step S40, then select the next to-be-tested mode of the bridge main girder, and repeat Step S20 to Step S30 until the bridge load test is completed.

[0014] In some embodiments, the step of then using the auxiliary excitation equipment to excite the bridge main girder at multiple maximum vibration modes corresponding to the to-be-tested mode, and keeping a preset phase difference between the vibration of the inertial mass block of each auxiliary excitation equipment and the vibration of the bridge main girder at its position, so that the bridge main girder enters a single-frequency steady-state vibration includes: Obtain the first vibration parameter of the inertial mass block of any auxiliary excitation equipment and the second vibration parameter at the contact position between it and the bridge main girder; Judge whether the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference; If so, keep the working parameters of the actuator of this auxiliary excitation equipment; if not, adjust the working parameters of the actuator of this auxiliary excitation equipment until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

[0015] In some embodiments, before the step of selecting a to-be-tested mode of the bridge main girder, it includes: Establish a finite element model of the bridge, and perform dynamic characteristic analysis according to the finite element model of the bridge to obtain multiple to-be-tested modes of the bridge main girder.

[0016] The beneficial effects brought by the technical solution provided by the present invention include: An embodiment of the present invention provides a multi-point steady-state excitation system and method for bridge load tests. The excitation system is provided with a main excitation device, a plurality of auxiliary excitation devices, and a main controller. One main excitation device actively excites at the frequency of the mode to be measured, and the remaining auxiliary excitation devices then follow the vibration of the bridge main girder for excitation, so as to achieve the purpose of multi-point synchronous excitation of the bridge main girder by multiple excitation devices. Through multi-point synchronous excitation, utilizing the resonance amplification effect, with a small number of excitation devices, it is possible to excite a significant single-frequency steady-state vibration of a super-long-span bridge with a span of more than one kilometer, and at the same time achieve the purposes of static load tests and dynamic load tests. The number of excitation devices required is small, the implementation process is simple, the time consumption is short, the cost is low, and the accuracy of the test results is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Schematic diagram of a multi-point steady-state excitation system for bridge load tests provided by an embodiment of the present invention; Figure 2 Schematic diagram of the main excitation device provided by an embodiment of the present invention; Figure 3 Comparison diagram of the steady-state excitation loading theoretical efficiency and the traditional static load test loading efficiency provided by an embodiment of the present invention; Figure 4 Schematic diagram of the installation position of the vibration sensor provided by an embodiment of the present invention; Figure 5 Flowchart of a multi-point steady-state excitation method for bridge load tests provided by an embodiment of the present invention; Reference Signs: 1. Main excitation device; 11. Tractor; 12. Hydraulic outrigger; 13. Control cabinet; 14. Power supply; 15. Excitation module; 151. Box body; 152. Actuator; 153. Inertial mass block; 154. Spring; 2. Auxiliary excitation device; 3. Main controller; 4. Bridge main girder; 5. Fixed sensor; 6. Unmanned inspection vehicle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] An embodiment of the present invention provides a multi-point steady-state excitation system for bridge load tests, which can solve the technical problems of the existing bridge load tests using traditional static load tests and dynamic load tests, such as requiring a large number of loading vehicles, long time consumption, high cost, and low accuracy of test results.

[0021] See Figure 1 As shown, an embodiment of the present invention provides a multi-point steady-state excitation system for bridge load tests, including: a main excitation device 1, a plurality of auxiliary excitation devices 2, and a main controller 3.

[0022] The main controller 3 is connected to the main excitation device 1 and the plurality of auxiliary excitation devices 2, and is configured to: Select a to-be-tested mode of the bridge main girder 4.

[0023] Use the main excitation device 1 to excite the bridge main girder 4 at a maximum vibration mode of the to-be-tested mode at the frequency of the to-be-tested mode, so that the bridge main girder 4 exhibits single-frequency vibration.

[0024] Then use the plurality of auxiliary excitation devices 2 to excite the bridge main girder 4 at a plurality of maximum vibration modes corresponding to the to-be-tested mode, and keep a preset phase difference between the vibration of the inertia mass block 153 of each auxiliary excitation device 2 and the vibration of the bridge main girder 4 at its location, so that the bridge main girder enters a single-frequency steady-state vibration with a larger amplitude. Among them, the preset phase difference is generally 90 degrees.

[0025] Then select the next to-be-tested mode of the bridge main girder 4, and repeat the process of using the main excitation device 1 and the plurality of auxiliary excitation devices 2 to excite the bridge main girder 4 to vibrate until the bridge load test is completed.

[0026] Specifically, see Figure 2As shown in the figure, the main excitation equipment 1 includes a tractor 11, hydraulic outriggers 12 provided at the lower end of the tractor 11, and a control cabinet 13, a power supply 14, and an excitation module 15 provided on the tractor 11. The excitation module 15 includes a box body 151, an actuator 152, an inertial mass block 153, and a spring 154. Among them, the tractor 11 can move at any time. The hydraulic outriggers 12 are used to contact the bridge deck to form a support. The control cabinet 13 is connected to the main controller 3. The power supply 14 provides power for the control cabinet 13 and the excitation module 15. The box body 151 of the excitation module 15 is fixed to the tractor 11. The actuator 152, the inertial mass block 153, and the spring 154 are connected to the box body 151. The actuator 152 acts according to the control instructions of the main controller 3 and the control cabinet 13 to excite the bridge girder 4. Optionally, the configurations of multiple auxiliary excitation equipment 2 are the same as that of the main excitation equipment 1.

[0027] For example, assume that there are a total of n excitation equipment. One of them is set as the main excitation equipment, and the remaining n - 1 are auxiliary excitation equipment. When starting the excitation, the actuator of the main excitation equipment excites the bridge girder at the frequency of the to-be-excited mode, and each auxiliary excitation equipment is not synchronized with the main excitation equipment. When the bridge girder shows obvious single-frequency vibration, control the auxiliary excitation equipment to start the excitation. In this way, the n - 1 auxiliary excitation equipment and the main excitation equipment together always make the vibration of the main girder continuously increase. Among them, the configuration of each excitation equipment is exactly the same, and each excitation equipment is set with two modes: Mode 1 is the active mode, that is, the motion frequency, motion displacement, and number of motion cycles are set; Mode 2 is the follow-up mode, which always keeps the vibration at the contact position with the bridge girder synchronized.

[0028] After realizing the multi-point synchronous steady-state excitation of the extra-long-span bridge through the above-mentioned multi-excitation equipment, the bridge girder will show significant single-frequency steady-state vibration, and it is possible to achieve high-precision measurement of the modal frequency, vibration mode, and damping ratio. After testing a certain mode, the excitation equipment quickly changes to the maximum vibration mode of another to-be-tested mode based on its own tractor, and then performs excitation and vibration testing. In this way, it is possible to quickly and conveniently achieve accurate testing of the dynamic characteristics of multiple modes.

[0029] Compared with the traditional static load test effect, the loading efficiency of the multi-point synchronous excitation equipment can achieve amplification of inertial force by dozens or hundreds of times due to the utilization of the resonance amplification effect, and the efficiency is much higher than that of the traditional static load vehicle loading, as shown in the following formula:

[0030] In the above formula, Y is the amplitude of the bridge girder, F is the amplitude of the harmonic inertial force, K is the stiffness of the to-be-excited mode of the bridge girder, M is the mass of the to-be-excited mode of the bridge girder, and ξ is the damping ratio of the to-be-excited mode.f is the excited modal frequency, A is the displacement amplitude of the inertial mass, m is the total weight of the inertial mass. If ξ = 0.5% is taken, then 1 / 2ξ = 100. Then, through the resonance amplification effect of steady-state excitation, the amplitude of the F simple harmonic inertial force can reach 100 times the static loading effect. Thus, the number of excitation devices can be effectively reduced. Figure 3 This is a comparison chart of the theoretical efficiency of steady-state excitation loading and the loading efficiency of traditional static load tests provided by the embodiments of the present invention.

[0031] In summary, in the bridge load test excitation system of the embodiments of the present invention, a main excitation device, a plurality of auxiliary excitation devices, and a main controller are provided. The main excitation device actively excites at the frequency of the to-be-measured mode, and the remaining auxiliary excitation devices then follow the vibration of the bridge main girder to excite, so that multiple excitation devices achieve the purpose of synchronously exciting the bridge main girder. Through multi-point synchronous excitation and using the resonance amplification effect, with a small number of excitation devices, it is possible to excite a significant single-frequency steady-state vibration of a super-long-span bridge with a span of more than a thousand meters, and at the same time achieve the purposes of static load tests and dynamic load tests. It requires fewer excitation devices, has a simple implementation process, short time consumption, low cost, and high test result accuracy.

[0032] As an optional implementation manner, in an embodiment of the invention, when using the plurality of auxiliary excitation devices 2 to excite the bridge main girder 4 at multiple maximum vibration modes corresponding to the to-be-measured mode and maintaining a preset phase difference between the vibration of the inertial mass block 153 of each auxiliary excitation device 2 and the vibration of the bridge main girder 4 at its position, so that the bridge main girder enters a single-frequency steady-state vibration, it includes: Obtaining the first vibration parameter of the inertial mass block 153 of any one of the auxiliary excitation devices 2 and the second vibration parameter at the contact position between it and the bridge main girder 4; Judging whether the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference; If so, maintaining the working parameters of the actuator 152 of the auxiliary excitation device 2; if not, adjusting the working parameters of the actuator 152 of the auxiliary excitation device 2 until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

[0033] Specifically, referring to Figure 4 As shown, vibration sensors are provided on the inertial mass blocks 153 of the main excitation device 1 and the plurality of auxiliary excitation devices 2, and at the contact positions between the main excitation device 1 and the plurality of auxiliary excitation devices 2 and the bridge main girder 4. Among them, the vibration sensor is an ultrasonic vibration sensor, a magnetoelectric vibration sensor, or a piezoelectric vibration sensor.

[0034] Referring to Figure 4As shown in the figure, the main excitation equipment 1 is provided with a No. 1 vibration sensor on the inertial mass block 153 and a No. 2 vibration sensor in contact with the bridge main girder 4. Each auxiliary excitation equipment 2 is provided with a No. 4 vibration sensor on the inertial mass block 153 and a No. 3 vibration sensor in contact with the bridge main girder 4. The No. 3 to No. 4 vibration sensors are connected to the main controller 3. When the bridge main girder 4 shows obvious single-frequency vibration, the action of the actuator 152 of the auxiliary excitation equipment 2 is controlled through the vibration curve of the bridge main girder 4 reflected by the collected No. 3 vibration sensor. If the phase difference between the first vibration parameter corresponding to the No. 4 vibration sensor and the second vibration parameter of the No. 3 vibration sensor is the preset phase difference (90 degrees), the working parameters of the actuator of the auxiliary excitation equipment are maintained; if the phase difference between the first vibration parameter corresponding to the No. 4 vibration sensor and the second vibration parameter of the No. 3 vibration sensor is not the preset phase difference (90 degrees), the working parameters of the actuator of the auxiliary excitation equipment are adjusted to keep the phase difference between the first vibration parameter and the second vibration parameter as the preset phase difference (90 degrees). Finally, the vibration of the inertial mass block 153 of the auxiliary excitation equipment 2 is always synchronized with the vibration of the bridge main girder 4, and the vibration of the bridge main girder 4 is continuously excited to increase.

[0035] As an optional implementation manner, in an invention embodiment, before selecting a to-be-tested mode of the bridge main girder 4, it includes: Establish a finite element model of the bridge, and perform dynamic characteristic analysis according to the finite element model of the bridge to obtain multiple to-be-tested modes of the bridge main girder 4.

[0036] The traditional static load test verification is static calculation, and most of the dynamic load tests only calculate the frequency and vibration mode through modal analysis. However, the finite element calculation in the invention embodiment adopts dynamic time history analysis, and the applied load is the harmonic force transmitted from the excitation equipment to the bridge. The magnitude data of this harmonic force is accurate, which is clearer and more accurate than the load of dozens or hundreds of loading vehicles in the static load test. Therefore, the data calculated therefrom is more accurate. In addition, the static load test tests the mechanical properties of the bridge through staged loading, while the steady-state excitation in the invention embodiment can obtain the dynamic strain time history curve and dynamic displacement deformation curve at the key positions of the bridge. By comparing and analyzing the above measured time history curves with the time history curves calculated by the dynamic finite element, the effect of staged loading with stepless change can be achieved.

[0037] In addition, for the dynamic characteristic response of the bridge, fixed sensors 5 (usually vibration sensors) can be arranged at key positions of the bridge in accordance with the "Code for Load Test of Highway Bridges" (JTG / T J21-01-2015), and combined with the slow movement test of multiple mobile light unmanned inspection vehicles 6, response information at more positions within the bridge deck range can be obtained. Further, multiple excitation devices, fixed sensors 5, and unmanned inspection vehicles 6 can be integrated into an intelligent control system through information means. Through presetting in the intelligent control system in advance, control multiple excitation devices to move to the maximum vibration mode of the to-be-excited mode, start and stop excitation with one key, and synchronize information such as dynamic displacement and dynamic strain of the bridge to the system, and automatically analyze and issue a test report for steady-state excitation. In this way, the preset professional knowledge can be efficiently utilized to quickly issue a professional test report, which is of great significance for the rapid performance evaluation of long-span bridges.

[0038] See Figure 5 As shown, an embodiment of the present invention also provides a bridge load test excitation method, including the following steps: Step S10, select a to-be-tested mode of the bridge main girder 4; Step S20, use the main excitation device 1 to excite the bridge main girder 4 at a maximum vibration mode of the to-be-tested mode at the frequency of the to-be-tested mode, so that the bridge main girder 4 undergoes single-frequency vibration; Step S30, then use multiple auxiliary excitation devices 2 to excite the bridge main girder 4 at multiple maximum vibration modes corresponding to the to-be-tested mode, and keep a preset phase difference between the vibration of the inertia mass block 153 of each auxiliary excitation device 2 and the vibration of the bridge main girder 4 at its contact position, so that the bridge main girder 4 enters single-frequency steady-state vibration; Step S40, then select the next to-be-tested mode of the bridge main girder 4, and repeat steps S20 to S30 until the bridge load test is completed.

[0039] As an optional implementation manner, in an embodiment of the invention, the step of then using the auxiliary excitation device 2 to excite the bridge main girder 4 at multiple maximum vibration modes corresponding to the to-be-tested mode, and keeping a preset phase difference between the vibration of the inertia mass block of each auxiliary excitation device 2 and the vibration of the bridge main girder 4 at its contact position, so that the bridge main girder 4 enters single-frequency steady-state vibration, includes: Obtain the first vibration parameter of the inertia mass block 153 of any auxiliary excitation device 2 and the second vibration parameter at the contact position between it and the bridge main girder 4; Judge whether the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference; If so, maintain the working parameters of the actuator 152 of the auxiliary excitation device 2; if not, adjust the working parameters of the actuator 152 of the auxiliary excitation device 2 until the phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference.

[0040] As an alternative embodiment, in an embodiment of the invention, before the step of selecting a to-be-measured mode of the bridge main girder 4, it includes: Establish a finite element model of the bridge, and perform dynamic characteristic analysis according to the finite element model of the bridge to obtain multiple to-be-measured modes of the bridge main girder 4.

[0041] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. Unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0042] It should be noted that in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0043] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can 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 these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features of the present invention described herein.

Claims

1. A multi-point steady-state excitation system for bridge load tests, characterized in that, Comprising: A main excitation device (1), a plurality of auxiliary excitation devices (2) and a main controller (3); The main controller (3) is connected to the main excitation device (1) and the plurality of auxiliary excitation devices (2), and is configured to: Select a to-be-tested mode of the bridge main girder (4); Use the main excitation device (1) to excite the bridge main girder (4) at a maximum vibration mode of the to-be-tested mode at the frequency of the to-be-tested mode, so that the bridge main girder (4) undergoes single-frequency vibration; Then use the plurality of auxiliary excitation devices (2) to excite the bridge main girder (4) at a plurality of maximum vibration modes corresponding to the to-be-tested mode, and keep a preset phase difference between the vibration of the inertia mass block (153) of each auxiliary excitation device (2) and the vibration of the bridge main girder (4) at its position, so that the bridge main girder (4) enters single-frequency steady-state vibration; Then select the next to-be-tested mode of the bridge main girder (4), and repeat the process of using the main excitation device (1) and the plurality of auxiliary excitation devices (2) to excite the bridge main girder (4) to vibrate until the bridge load test is completed.

2. The multi-point steady-state excitation system for bridge load test according to claim 1, wherein: The main excitation device (1) includes a tractor (11), a hydraulic support leg (12) provided at the lower end of the tractor (11), and a control cabinet (13), a power supply (14), and an excitation module (15) provided on the tractor (11). The excitation module (15) includes a box body (151), an actuator (152), an inertia mass block (153), and a spring (154).

3. The multi-point steady-state excitation system for bridge load tests according to claim 2, wherein: The configurations of the plurality of auxiliary excitation devices (2) are the same as that of the main excitation device (1).

4. The multi-point steady-state excitation system for bridge load test according to claim 3, characterized in that The step of then using the plurality of auxiliary excitation devices (2) to excite the bridge main girder (4) at a plurality of maximum vibration modes corresponding to the to-be-tested mode, and keeping a preset phase difference between the vibration of the inertia mass block (153) of each auxiliary excitation device (2) and the vibration of the bridge main girder (4) at its position, so that the bridge main girder (4) enters single-frequency steady-state vibration, includes: Obtain the first vibration parameter of the inertia mass block (153) of any auxiliary excitation device (2) and the second vibration parameter at the contact position between it and the bridge main girder (4); Judge whether the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference; If so, keep the working parameters of the actuator (152) of the auxiliary excitation device (2); if not, adjust the working parameters of the actuator (152) of the auxiliary excitation device (2) until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

5. The multi-point steady-state excitation system for bridge load test according to claim 4, wherein: Vibration sensors are provided on the inertia mass blocks (153) of the main excitation device (1) and the plurality of auxiliary excitation devices (2), and at the contact positions between the main excitation device (1) and the plurality of auxiliary excitation devices (2) and the bridge main girder (4).

6. The multi-point steady-state excitation system for bridge load test according to claim 5, wherein: The vibration sensor is an ultrasonic vibration sensor, a magnetoelectric vibration sensor or a piezoelectric vibration sensor.

7. The multi-point steady-state excitation system for bridge load tests according to claim 1, characterized in that, Before selecting a modal to be measured of the bridge main girder (4), it includes: Establish a finite element model of the bridge, and perform dynamic characteristic analysis based on the finite element model of the bridge to obtain multiple modals to be measured of the bridge main girder (4).

8. A multi-point steady-state excitation method for bridge load tests, using the bridge load test excitation system described in claim 1, characterized in that, It includes the following steps: Step S10, select a modal to be measured of the bridge main girder (4); Step S20, use the main excitation equipment (1) to excite the bridge main girder (4) at a maximum vibration mode of the modal to be measured at the frequency of the modal to be measured, so that the bridge main girder (4) undergoes single-frequency vibration; Step S30, then use multiple auxiliary excitation equipment (2) to excite the bridge main girder (4) at multiple maximum vibration modes corresponding to the modal to be measured, and keep a preset phase difference between the vibration of the inertial mass block (153) of each auxiliary excitation equipment (2) and the vibration of the bridge main girder (4) at its location, so that the bridge main girder (4) enters single-frequency steady-state vibration; Step S40, then select the next modal to be measured of the bridge main girder (4), and repeat Step S20 to Step S30 until the bridge load test is completed.

9. The multi-point steady-state excitation method for bridge load test according to claim 8, characterized in that The step of then using the auxiliary excitation equipment (2) to excite the bridge main girder (4) at multiple maximum vibration modes corresponding to the modal to be measured, and keeping a preset phase difference between the vibration of the inertial mass block of each auxiliary excitation equipment (2) and the vibration of the bridge main girder (4) at its location, so that the bridge main girder (4) enters single-frequency steady-state vibration includes: Obtain the first vibration parameter of the inertial mass block (153) of any auxiliary excitation equipment (2) and the second vibration parameter at the contact position between it and the bridge main girder (4); Judge whether the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference; If so, keep the working parameters of the actuator (152) of this auxiliary excitation equipment (2); if not, adjust the working parameters of the actuator (152) of this auxiliary excitation equipment (2) until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

10. The multi-point steady-state excitation method for bridge load test according to claim 8, characterized in that Before the step of selecting a modal to be measured of the bridge main girder (4), it includes: Establish a finite element model of the bridge, and perform dynamic characteristic analysis based on the finite element model of the bridge to obtain multiple modals to be measured of the bridge main girder (4).

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