A multi-point steady-state excitation system and method for bridge load testing

Abstract

The present invention discloses a multi-point steady-state excitation system and method for bridge load testing, which relates to the technical field of bridge testing, and includes: a main excitation device, a plurality of auxiliary excitation devices, and a main controller; the main controller is configured to: select a mode to be tested of the bridge main beam; use the main excitation device to excite the bridge main beam at a maximum vibration mode of the mode to be tested at the frequency of the mode to be tested, so that the bridge main beam vibrates at a single frequency; use a plurality of auxiliary excitation devices to excite the bridge main beam at a plurality of maximum vibration modes corresponding to the mode to be tested, 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 beam at its location; select the next mode to be tested of the bridge main beam, and repeat the process of exciting the bridge main beam vibration until the bridge load test is completed. The present invention can excite the bridge to a significant single-frequency steady-state vibration, and simultaneously achieve the purpose of static load testing and dynamic load testing, requires less excitation equipment, and has high test result accuracy.

Description

Technical Field

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

[0002] Currently, the number of cable-supported bridges with main spans exceeding one kilometer is increasing, both newly constructed and in operation. The main spans of large-span cable-stayed bridges currently under construction reach 1,208 meters, those of cable-stayed suspension bridges reach 1,488 meters, and those of suspension bridges reach 2,300 meters. These bridges are extremely expensive to construct and serve as crucial hubs for various transportation routes, making accurate performance assessment crucial.

[0003] Bridge performance assessment during completion acceptance or during operation typically involves load testing, which consists of both static and dynamic load tests. Static load testing measures the stresses, strains, and structural deformations of key control sections under static loads to determine whether the structure's actual operating performance meets design expectations. The loading condition typically involves applying the maximum load to the bridge's most unfavorable location. The primary method involves loading heavy vehicles to simulate the traffic loads experienced during normal operation. For example, a double-deck, long-span highway suspension bridge with 12 lanes would require the deployment of over 400 heavy vehicles (approximately 30 tons). This presents significant challenges in vehicle coordination and disruption to surrounding traffic. Any problems could potentially impact the structural safety of approach bridges and ramps on both sides. Therefore, for bridges with extremely long spans, traditional static load testing requires numerous vehicles, is challenging to implement, is time-consuming, and economically expensive. There is an urgent need to find more scientific alternatives to traditional static load testing.

[0004] Traditional dynamic load tests primarily test bridge parameters such as frequency, mode shape, and damping ratio. The excitation method can be determined based on the structural characteristics, test accuracy requirements, convenience, and actual site conditions. Environmental random excitation, vehicle-driven excitation, and vehicle-jumping excitation are recommended. Exciter excitation or other excitation methods are also acceptable. For long-span bridges, the excitation capacity of heavy vehicle input is very limited. The bridge's dynamic response signal has an extremely low signal-to-noise ratio, complex modal components, and uncontrollable modal order. Consequently, the frequency, mode shape, and damping ratio obtained from the test are limited. This is especially true for the damping ratio. Due to the low signal-to-noise ratio of the bridge's vibration response, the identified damping ratio is less accurate and exhibits high dispersion across multiple measurements. Summary of the Invention

[0005] The embodiment of the present invention provides a multi-point steady-state excitation system and method for bridge load testing to solve the technical problems in the related art that the existing bridge load test adopts traditional static load test and dynamic load test, which requires many loading vehicles, is time-consuming and expensive, and the test results are not accurate.

[0006] In a first aspect, a multi-point steady-state vibration excitation system for a bridge load test is provided, comprising: a main vibration excitation device, a plurality of auxiliary vibration excitation devices, and a main controller;

[0007] The main controller is connected to the main excitation device and the plurality of auxiliary excitation devices, and is configured to:

[0008] Select a mode to be measured for the bridge girder;

[0009] Using the main excitation equipment to excite the bridge main beam at a maximum vibration mode of the mode to be measured at the frequency of the mode to be measured, so that the bridge main beam vibrates at a single frequency;

[0010] Then, multiple auxiliary excitation devices are used to excite the bridge main beam at multiple maximum vibration modes corresponding to the mode to be measured, and a preset phase difference is maintained between the vibration of the inertial mass block of each auxiliary excitation device and the vibration of the bridge main beam at its location, so that the bridge main beam enters a single-frequency steady-state vibration;

[0011] Then, the next mode to be tested of the bridge main beam is selected, and the process of exciting the vibration of the bridge main beam using the main excitation equipment and the plurality of auxiliary excitation equipment is repeated until the bridge load test is completed.

[0012] In some embodiments, the main excitation equipment includes a tractor, a hydraulic support leg 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, an actuator, an inertial mass block, and a spring.

[0013] In some embodiments, the configuration of the plurality of auxiliary excitation devices is the same as that of the main excitation device.

[0014] In some embodiments, the method of using multiple auxiliary excitation devices to excite the bridge main beam at multiple maximum vibration modes corresponding to the mode to be measured, 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 beam at its location, so that the bridge main beam enters a single-frequency steady-state vibration, includes:

[0015] Obtaining a first vibration parameter of an inertial mass block of any auxiliary vibration excitation equipment and a second vibration parameter at a contact position between the inertial mass block and a bridge main beam;

[0016] determining whether a phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference;

[0017] If so, the operating parameters of the actuator of the auxiliary excitation equipment are maintained; if not, the operating parameters of the actuator of the auxiliary excitation equipment are adjusted until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

[0018] In some embodiments, vibration sensors are provided on the inertial mass blocks of the main excitation equipment and the plurality of auxiliary excitation equipment, as well as at the contact positions between the main excitation equipment and the plurality of auxiliary excitation equipment and the main beam of the bridge.

[0019] In some embodiments, the vibration sensor is an ultrasonic vibration sensor, a magnetoelectric vibration sensor, or a piezoelectric vibration sensor.

[0020] In some embodiments, before selecting a mode to be measured of a bridge girder, the method includes:

[0021] A finite element model of the bridge is established, and a dynamic characteristic analysis is performed based on the finite element model of the bridge to obtain multiple modes to be measured of the bridge main beam.

[0022] In a second aspect, a multi-point steady-state excitation method for a bridge load test is provided, comprising the following steps:

[0023] Step S10, selecting a mode to be measured of the bridge main beam;

[0024] Step S20, using a main excitation device to excite the bridge main beam at a maximum vibration mode of the mode to be measured at the frequency of the mode to be measured, so that the bridge main beam vibrates at a single frequency;

[0025] Step S30: Multiple auxiliary excitation devices are then used to excite the bridge girder at multiple maximum vibration modes corresponding to the mode to be measured, and a preset phase difference is maintained between the vibration of the inertial mass block of each auxiliary excitation device and the vibration of the bridge girder at its location, so that the bridge girder enters a single-frequency steady-state vibration;

[0026] In step S40, the next mode to be tested of the bridge main beam is selected, and steps S20 to S30 are repeated until the bridge load test is completed.

[0027] In some embodiments, the step of using the auxiliary excitation equipment to excite the bridge main beam at multiple maximum vibration modes corresponding to the mode to be measured, and maintaining a preset phase difference between the vibration of the inertial mass block of each auxiliary excitation equipment and the vibration of the bridge main beam at its location, so as to cause the bridge main beam to enter a single-frequency steady-state vibration, includes:

[0028] Obtaining a first vibration parameter of an inertial mass block of any auxiliary excitation equipment and a second vibration parameter at a contact position between the inertial mass block and the bridge main beam;

[0029] determining whether a phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference;

[0030] If so, the operating parameters of the actuator of the auxiliary vibration equipment are maintained; if not, the operating parameters of the actuator of the auxiliary vibration equipment are adjusted until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

[0031] In some embodiments, before the step of selecting a mode to be measured of a bridge girder, the method includes:

[0032] A finite element model of the bridge is established, and a dynamic characteristic analysis is performed based on the finite element model of the bridge to obtain multiple modes to be measured of the bridge main beam.

[0033] The beneficial effects brought about by the technical solution provided by the present invention include:

[0034] An embodiment of the present invention provides a multi-point steady-state vibration excitation system and method for bridge load testing. The excitation system is equipped with a main excitation device, multiple auxiliary excitation devices, and a main controller. A main excitation device actively excites at the frequency of the mode to be tested, while the remaining auxiliary excitation devices follow the vibration of the bridge main beam and are then excited. This allows multiple excitation devices to achieve the purpose of multi-point synchronous excitation of the bridge main beam. Through multi-point synchronous excitation, utilizing the resonance amplification effect, and using a small amount of excitation equipment, it is possible to excite a large-span bridge of over a kilometer in size to produce significant single-frequency steady-state vibration, achieving both static and dynamic load testing simultaneously. This requires minimal excitation equipment, resulting in a simple, time-efficient, and inexpensive implementation process and highly accurate test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A schematic diagram of a multi-point steady-state excitation system for a bridge load test provided by an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a main excitation device provided in an embodiment of the present invention;

[0038] Figure 3 A comparison chart of the theoretical efficiency of steady-state excitation loading and the loading efficiency of traditional static load tests provided by an embodiment of the present invention;

[0039] Figure 4 A schematic diagram of the installation position of the vibration sensor provided in an embodiment of the present invention;

[0040] Figure 5 A flow chart of a multi-point steady-state excitation method for a bridge load test provided by an embodiment of the present invention;

[0041] Reference numerals:

[0042] 1. Main excitation equipment; 11. Tractor; 12. Hydraulic outriggers; 13. Control cabinet; 14. Power supply; 15. Excitation module; 151. Box; 152. Actuator; 153. Inertial mass block; 154. Spring;

[0043] 2. Auxiliary excitation equipment;

[0044] 3. Main controller;

[0045] 4. Bridge girder;

[0046] 5. Fixed sensor;

[0047] 6. Unmanned inspection vehicle. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 making creative efforts shall fall within the scope of protection of the present invention.

[0049] An embodiment of the present invention provides a multi-point steady-state excitation system for bridge load testing, which can solve the technical problems that existing bridge load tests use traditional static load tests and dynamic load tests, which require many loading vehicles, are time-consuming and expensive, and have low test result accuracy.

[0050] See also Figure 1 As shown, an embodiment of the present invention provides a multi-point steady-state excitation system for bridge load testing, including: a main excitation device 1, multiple auxiliary excitation devices 2 and a main controller 3.

[0051] The main controller 3 is connected to the main excitation device 1 and the plurality of auxiliary excitation devices 2, and is configured as follows:

[0052] A mode to be measured of the bridge main beam 4 is selected.

[0053] The main excitation equipment 1 is used to excite the bridge main beam 4 at a maximum vibration mode of the mode to be measured at the frequency of the mode to be measured, so that the bridge main beam 4 vibrates at a single frequency.

[0054] Multiple auxiliary excitation devices 2 are then used to excite the bridge girder 4 at multiple maximum vibration modes corresponding to the mode to be measured. A preset phase difference is maintained between the vibration of the inertial mass 153 of each auxiliary excitation device 2 and the vibration of the bridge girder 4 at its location, causing the bridge girder to enter a single-frequency steady-state vibration with a large amplitude. The preset phase difference is generally 90 degrees.

[0055] Then, the next mode to be tested of the bridge main beam 4 is selected, and the process of using the main excitation equipment 1 and the plurality of auxiliary excitation equipment 2 to excite the vibration of the bridge main beam 4 is repeated until the bridge load test is completed.

[0056] Specifically, see Figure 2 As shown, the main excitation device 1 includes a tractor 11, hydraulic legs 12 located at the lower end of the tractor 11, a control cabinet 13, a power supply 14, and an excitation module 15 located on the tractor 11. The excitation module 15 includes a housing 151, an actuator 152, an inertial mass block 153, and a spring 154. The tractor 11 is movable at any time. The hydraulic legs 12 are used to contact and support the bridge deck. The control cabinet 13 is connected to the main controller 3. The power supply 14 provides power to the control cabinet 13 and the excitation module 15. The housing 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 housing 151. The actuator 152 operates according to control instructions from the main controller 3 and the control cabinet 13 to excite the bridge main beam 4. Optionally, multiple auxiliary excitation devices 2 have the same configuration as the main excitation device 1.

[0057] For example, suppose there are n excitation devices in total, one of which is set as the main excitation device, and the remaining n-1 are auxiliary excitation devices. When the excitation starts, the actuator of the main excitation device excites the main beam of the bridge at the frequency of the mode to be excited, and the auxiliary excitation devices are not synchronized with the main excitation device. When the main beam of the bridge exhibits obvious single-frequency vibration, the auxiliary excitation devices are controlled to start excitation. In this way, the n-1 auxiliary excitation devices and the main excitation device together always excite the vibration of the main beam to become larger and larger. Among them, the configuration of each excitation device is exactly the same, and each excitation device is set to 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 synchronization with the vibration at the contact position of the main beam of the bridge.

[0058] By achieving multi-point synchronous steady-state excitation of an extra-long span bridge using multiple excitation devices, the bridge's main beam exhibits significant single-frequency steady-state vibration, enabling highly accurate measurement of modal frequencies, mode shapes, and damping ratios. After testing a particular mode, the excitation device, using its own tractor, rapidly switches to the maximum mode shape of the next mode under test, repeating the excitation and vibration testing. This repetitive process allows for rapid and convenient precise testing of the dynamic characteristics of multiple modes.

[0059] Compared with the traditional static load test, the loading efficiency of the multi-point synchronous excitation equipment can achieve amplification of inertial force by dozens or even hundreds of times due to the use of the resonance amplification effect. The efficiency is much higher than that of traditional static load vehicle loading, as shown in the following formula:

[0060]

[0061] In the above formula, Y is the bridge girder amplitude, F is the amplitude of the simple harmonic inertial force, K is the excited modal stiffness of the bridge girder, M is the excited modal mass of the bridge girder, ξ is the damping ratio of the excited mode, f is the excited modal frequency, A is the displacement amplitude of the inertial mass, m is the total inertial mass. If ξ=0.5%, then 1 / 2ξ=100, and the amplitude is F The simple harmonic inertia force can achieve 100 times the static loading effect, which can effectively reduce the number of excitation equipment. Figure 3 A comparison chart of the theoretical efficiency of steady-state excitation loading provided by an embodiment of the present invention and the loading efficiency of a traditional static load test.

[0062] In summary, the bridge load test excitation system in the embodiment of the present invention is provided with a main excitation device, multiple auxiliary excitation devices and a main controller. A main excitation device is actively excited at the frequency of the mode to be measured, and the remaining auxiliary excitation devices are then excited following the vibration of the bridge main beam, so that multiple excitation devices can achieve the purpose of synchronously exciting the bridge main beam. Through multi-point synchronous excitation, utilizing the resonance amplification effect, and using a small amount of excitation equipment, it is possible to excite a significant single-frequency steady-state vibration of a super-large span bridge of more than a kilometer level, and at the same time achieve the purposes of static load test and dynamic load test. Less excitation equipment is required, the implementation process is simple, short in time, low in cost, and the test results are highly accurate.

[0063] As an optional implementation, in one embodiment of the invention, the method of reusing multiple auxiliary excitation devices 2 to excite the bridge main beam 4 at multiple maximum vibration modes corresponding to the mode to be measured, 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 beam 4 at its location, so that the bridge main beam enters a single-frequency steady-state vibration, includes:

[0064] Obtaining a first vibration parameter of the inertial mass block 153 of any of the auxiliary excitation devices 2 and a second vibration parameter at a contact position between the inertial mass block 153 and the bridge main beam 4;

[0065] determining whether a phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference;

[0066] If so, maintain the operating parameters of the actuator 152 of the auxiliary excitation equipment 2; if not, adjust the operating parameters of the actuator 152 of the auxiliary excitation equipment 2 until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

[0067] Specifically, see 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, as well as at the contact points between the main excitation device 1 and the plurality of auxiliary excitation devices 2 and the bridge main beam 4. The vibration sensors are ultrasonic, magnetoelectric, or piezoelectric sensors.

[0068] See also Figure 4 As shown, the main excitation equipment 1 is provided with a vibration sensor No. 1 on the inertial mass block 153, and a vibration sensor No. 2 is provided in contact with the bridge main beam 4. Each auxiliary excitation equipment 2 is provided with a vibration sensor No. 4 on the inertial mass block 153, and a vibration sensor No. 3 is provided in contact with the bridge main beam 4. The vibration sensors No. 3 to No. 4 are connected to the main controller 3. When the bridge main beam 4 exhibits obvious single-frequency vibration, the action of the actuator 152 of the auxiliary excitation equipment 2 is controlled by the vibration curve of the bridge main beam 4 reflected by the collected vibration sensor No. 3. If the first vibration parameter corresponding to the vibration sensor No. 4 is the same as that of the vibration sensor No. 3, the actuator 152 of the auxiliary excitation equipment 2 is controlled. The phase difference of the second vibration parameter of the vibration sensor is a preset phase difference (90 degrees), and the working parameters of the actuator of the auxiliary excitation equipment are maintained; if the phase difference between the first vibration parameter corresponding to vibration sensor No. 4 and the second vibration parameter of vibration sensor No. 3 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 at the preset phase difference (90 degrees), and 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 beam 4, thereby stimulating the vibration of the bridge main beam 4 to become larger and larger.

[0069] As an optional implementation manner, in an embodiment of the invention, before selecting a mode to be measured of the bridge main beam 4, the method includes:

[0070] A finite element model of the bridge is established, and a dynamic characteristic analysis is performed based on the finite element model of the bridge to obtain multiple modes to be measured of the bridge main beam 4.

[0071] Traditional static load test verification is static calculation, and dynamic load test mostly only calculates frequency and vibration mode through modal analysis. However, the finite element calculation of the embodiment of the present invention adopts dynamic time history analysis. The applied load is the simple harmonic force transmitted to the bridge at the excitation equipment. The magnitude data of this simple harmonic force is precise and clearer and more accurate than the load of dozens or hundreds of loading vehicles in static load test. The data calculated in this way is more accurate. In addition, the static load test tests the mechanical properties of the bridge through graded loading, while the steady-state excitation of the embodiment of the present invention can obtain the dynamic strain time history curve and dynamic displacement deformation curve of the key position of the bridge. By comparing and analyzing the above-mentioned measured time history curve with the time history curve calculated by dynamic finite element, a stepless graded loading effect can be achieved.

[0072] Furthermore, for the dynamic response of bridges, fixed sensors 5 (typically vibration sensors) can be deployed at key locations on the bridge in accordance with the "Highway Bridge Load Test Procedure" (JTG / T J21-01-2015). Combined with slow-moving testing using multiple mobile, lightweight, unmanned inspection vehicles 6, this can provide response information from a wider range of locations within the bridge deck. Furthermore, multiple excitation devices, fixed sensors 5, and unmanned inspection vehicles 6 can be integrated into an intelligent control system through information technology. Pre-set settings within the intelligent control system control the multiple excitation devices to the maximum vibration mode of the desired mode, enabling a single-button start and stop of excitation. The system then synchronizes information such as the bridge's dynamic displacement and strain to the system, allowing for automated analysis and the generation of a steady-state excitation test report. This approach allows for efficient utilization of pre-established specialized knowledge and rapid production of specialized test reports, which is crucial for the rapid performance evaluation of long-span bridges.

[0073] See also Figure 5 As shown, an embodiment of the present invention further provides a bridge load test vibration excitation method, comprising the following steps:

[0074] Step S10, selecting a mode to be measured of the bridge main beam 4;

[0075] Step S20, using the main excitation equipment 1 to excite the bridge main beam 4 at a maximum vibration mode of the mode to be measured at the frequency of the mode to be measured, so that the bridge main beam 4 vibrates at a single frequency;

[0076] In step S30, multiple auxiliary excitation devices 2 are used to excite the bridge girder 4 at multiple maximum vibration modes corresponding to the mode to be measured, and a preset phase difference is maintained between the vibration of the inertial mass block 153 of each auxiliary excitation device 2 and the vibration of the bridge girder 4 at its location, so that the bridge girder 4 enters a single-frequency steady-state vibration.

[0077] In step S40, the next mode to be tested of the bridge main beam 4 is selected, and steps S20 to S30 are repeated until the bridge load test is completed.

[0078] As an optional implementation, in one embodiment of the invention, the step of reusing the auxiliary excitation equipment 2 to excite the bridge main beam 4 at multiple maximum vibration modes corresponding to the mode to be measured, and maintaining 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 beam 4 at its location, so as to cause the bridge main beam 4 to enter a single-frequency steady-state vibration, includes:

[0079] Obtaining a first vibration parameter of the inertial mass block 153 of any auxiliary vibration excitation device 2 and a second vibration parameter at a contact position between the inertial mass block 153 and the bridge main beam 4;

[0080] determining whether a phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference;

[0081] If so, the operating parameters of the actuator 152 of the auxiliary excitation equipment 2 are maintained; if not, the operating parameters of the actuator 152 of the auxiliary excitation equipment 2 are adjusted until the phase difference between the first vibration parameter and the second vibration parameter is the preset phase difference.

[0082] As an optional implementation, in one embodiment of the invention, before the step of selecting a mode to be measured of the bridge main beam 4, the following steps are included:

[0083] A finite element model of the bridge is established, and a dynamic characteristic analysis is performed based on the finite element model of the bridge to obtain multiple modes to be measured of the bridge main beam 4.

[0084] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between 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 the specific circumstances.

[0085] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0086] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those 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 is not intended to be limited to the embodiments shown herein, but is to be construed in the widest possible manner consistent with the principles and novel features of the present invention.

Claims

1. A multi-point steady-state excitation system for bridge load testing, characterized in that: include: 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 equipment (1) and the plurality of auxiliary excitation equipment (2), and is configured to: Select a mode to be measured of the bridge girder (4); Using the main excitation equipment (1) to excite the bridge main beam (4) at a maximum vibration mode of the mode to be measured at the frequency of the mode to be measured, so that the bridge main beam (4) vibrates at a single frequency; Then, a plurality of the auxiliary excitation devices (2) are used to excite the bridge main beam (4) at a plurality of maximum vibration modes corresponding to the mode to be measured, and a preset phase difference is maintained between the vibration of the inertial mass block (153) of each auxiliary excitation device (2) and the vibration of the bridge main beam (4) at the location thereof, so that the bridge main beam (4) enters a single-frequency steady-state vibration; Then, the next mode to be tested of the bridge main beam (4) is selected, and the process of exciting the vibration of the bridge main beam (4) by using the main excitation device (1) and the plurality of auxiliary excitation devices (2) is repeated until the bridge load test is completed.

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

3. The multi-point steady-state excitation system for bridge load testing according to claim 2 is characterized in that: The configuration of the plurality of auxiliary excitation devices (2) is the same as that of the main excitation device (1).

4. The multi-point steady-state excitation system for bridge load testing according to claim 3 is characterized in that: The method further uses a plurality of the auxiliary excitation devices (2) to excite the bridge main beam (4) at a plurality of maximum vibration modes corresponding to the mode to be measured, and maintains 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 beam (4) at the position where the inertial mass block (153) is located, so that the bridge main beam (4) enters a single frequency steady-state vibration, including: Obtaining a first vibration parameter of the inertial mass block (153) of any auxiliary vibration excitation device (2) and a second vibration parameter at a contact position between the inertial mass block (153) and the bridge main beam (4); determining whether a phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference; If so, the operating parameters of the actuator (152) of the auxiliary excitation equipment (2) are maintained; if not, the operating parameters of the actuator (152) of the auxiliary excitation equipment (2) are adjusted until the phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference.

5. The multi-point steady-state excitation system for bridge load testing according to claim 4 is characterized in that: Vibration sensors are provided on the inertial mass blocks (153) of the main excitation equipment (1) and the plurality of auxiliary excitation equipment (2), as well as at contact positions between the main excitation equipment (1) and the plurality of auxiliary excitation equipment (2) and the main beam (4) of the bridge.

6. The multi-point steady-state excitation system for bridge load testing according to claim 5 is characterized in that: 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 testing according to claim 1 is characterized in that: Before selecting a mode to be measured of the bridge main beam (4), the method includes: A finite element model of the bridge is established, and a dynamic characteristic analysis is performed based on the finite element model of the bridge to obtain multiple modes to be measured of the bridge main beam (4).

8. A multi-point steady-state vibration excitation method for bridge load testing, using the bridge load testing vibration excitation system according to claim 1, characterized in that: The following steps are involved: Step S10, selecting a mode to be measured of the bridge main beam (4); Step S20, using the main excitation equipment (1) to excite the bridge main beam (4) at a maximum vibration mode of the mode to be measured at the frequency of the mode to be measured, so that the bridge main beam (4) vibrates at a single frequency; Step S30, using multiple auxiliary excitation devices (2) to excite the bridge main beam (4) at multiple maximum vibration modes corresponding to the mode to be measured, 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 beam (4) at its location, so that the bridge main beam (4) enters a single frequency steady-state vibration; In step S40, the next mode to be tested of the bridge main beam (4) is selected, and steps S20 to S30 are repeated until the bridge load test is completed.

9. The multi-point steady-state excitation method for bridge load testing according to claim 8, characterized in that: The step of using a plurality of auxiliary excitation devices (2) to excite the bridge main beam (4) at a plurality of maximum vibration modes corresponding to the mode to be measured, 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 beam (4) at the position where the inertial mass block (153) is located, so that the bridge main beam (4) enters a single frequency steady-state vibration, comprises: Obtaining a first vibration parameter of an inertial mass block (153) of any auxiliary excitation equipment (2) and a second vibration parameter at a contact position between the inertial mass block (153) and the bridge main beam (4); determining whether a phase difference between the first vibration parameter and the second vibration parameter is a preset phase difference; If so, the operating parameters of the actuator (152) of the auxiliary excitation equipment (2) are maintained; if not, the operating parameters of the actuator (152) of the auxiliary excitation equipment (2) are adjusted 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 testing according to claim 8, characterized in that: Before the step of selecting a mode to be measured of the bridge main beam (4), the method includes: A finite element model of the bridge is established, and a dynamic characteristic analysis is performed based on the finite element model of the bridge to obtain multiple modes to be measured of the bridge main beam (4).

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