Buffeting load multi-point synchronous measurement device and method for large-span arch bridge wind tunnel test

Abstract

The invention discloses a buffeting load multi-point synchronous measurement device and method for a large-span arch bridge wind tunnel test. The device comprises a base, a wind direction angle adjusting mechanism, an arch bridge truss model, a model supporting system and a multi-channel synchronous data acquisition system. The arch bridge truss model comprises at least two test segments embedded with six-component balances, the six-component balances are located in the geometric centers of the segments and fixedly connected with the main framework through rigid force transmission structures, and gaps are formed between the adjacent segments; the wind direction angle adjusting mechanism rotates around a vertical shaft, and the model supporting system is matched with the wind attack angle adjusting mechanism through a supporting stand column to achieve overall pitching of the arch bridge truss model so as to adjust the wind attack angle of the arch bridge truss model. And the multi-channel synchronous data acquisition system synchronously acquires time history signals of the three-dimensional aerodynamic force borne by each test section. According to the invention, double-degree-of-freedom independent adjustment, multi-point synchronous force measurement and load field reconstruction can be realized, the method is suitable for arch ribs with different curvatures, and meanwhile, the buffeting load identification precision of the large-span arch bridge can be remarkably improved.

Description

Technical Field

[0001] This application relates to the field of bridge wind engineering technology, and in particular to a multi-point synchronous measurement device and method for buffeting load in wind tunnel tests of long-span arch bridges. It is suitable for accurately obtaining the three-dimensional buffeting load distributed along the span direction of the arch bridge structure in a turbulent wind field, and directly identifying the aerodynamic admittance function and spatial coherence characteristics. Background Technology

[0002] Long-span arch bridges, as a key form of modern transportation infrastructure, are increasingly demonstrating their economic and aesthetic value. However, with the continuous increase in span and the increasing flexibility of the structure, their sensitivity to wind loads has also significantly increased. Buffeting, a type of limited vibration induced by natural atmospheric turbulence, while not causing devastating divergences like flutter, is the most common wind-induced vibration phenomenon encountered by bridges during operation. Long-term buffeting response can lead to structural fatigue, affecting driving safety and comfort, and may ultimately limit the service life and performance of the bridge. Therefore, accurately acquiring the buffeting load acting on the arch bridge structure is a fundamental prerequisite for accurate prediction of wind-induced vibration response and assessment of structural safety and reliability.

[0003] However, existing technologies are mostly used for force measurement studies on simple beam bridge sections, lacking specialized wind load measurement devices for complex spatial structures like arch bridges. The arch ribs, suspenders, and other components of an arch bridge are interconnected, resulting in a significantly different aerodynamic load distribution characteristics compared to beam bridges. Traditional single-balance force measurement can only obtain the overall aerodynamic force of the arch bridge truss model, failing to simultaneously measure the individual aerodynamic loads borne by different components such as the main beams and arch ribs.

[0004] Meanwhile, aerodynamic admittance is a key aerodynamic parameter in bridge buffeting analysis, used to describe the structure's wind-force correction effect on incoming turbulent flow. Its accuracy directly determines the reliability of buffeting response prediction. Currently, the main methods for identifying aerodynamic admittance are the indirect method and the direct method. The indirect method calculates aerodynamic forces by measuring the vibration response, which is theoretically complex and greatly affected by the structural dynamic characteristics. The direct method calculates aerodynamic admittance by simultaneously measuring wind load and wind speed time histories, which is technically challenging. Existing direct method force measurement experimental devices can mostly only measure aerodynamic forces and cannot simultaneously obtain the vibration displacement time histories of the arch bridge truss model, making it difficult to perform force-response coupling verification; moreover, traditional experimental devices are fixed in wind tunnels, making it difficult to quickly and accurately adjust the wind direction angle and wind attack angle of the arch bridge truss model, and even more difficult to simulate the transformation of different arch axis alignments, resulting in low experimental efficiency. At the same time, the support system of traditional arch bridge truss models often introduces significant aerodynamic or mechanical interference, affecting the accuracy of the force balance.

[0005] Therefore, there is an urgent need for an integrated, high-precision testing system that can simultaneously measure the buffeting load and response of arch bridges under flexible adjustment of multiple parameters. Summary of the Invention

[0006] To overcome the problems existing in the prior art, such as the inability to simultaneously measure multiple points of buffeting load, difficulty in flexibly adjusting the wind attack angle and wind direction angle, and large interference in the support system, this application provides a device and method for simultaneous multi-point measurement of buffeting load for wind tunnel testing of long-span arch bridges.

[0007] The first objective of this application is to provide a multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges.

[0008] The aforementioned objective of this application is achieved through the following technical solution:

[0009] A multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges, the device comprising:

[0010] Base;

[0011] A wind direction angle adjustment mechanism is fixedly connected to the lower part of the base, which is used to drive the base to rotate around the vertical axis to set the wind direction angle;

[0012] An arch bridge truss model includes at least two test segments. Each test segment contains a force measuring unit, which includes a six-component balance and a rigid force transmission structure. The six-component balance is fixedly connected to the main load-bearing frame of the corresponding test segment through the rigid force transmission structure. The six-component balance is completely embedded inside the test segment and located at the geometric center of the test segment. There are gaps between adjacent segments of the arch bridge truss model to achieve mechanical decoupling.

[0013] The model support system installed on the base includes a support column installed on the base and a wind attack angle adjustment mechanism disposed on the support column. The wind attack angle adjustment mechanism is connected to the arch bridge truss model and is used to adjust the wind attack angle of the arch bridge truss model.

[0014] A multi-channel synchronous data acquisition system is electrically connected to a six-component balance of all force measurement units. The multi-channel synchronous data acquisition system is used to synchronously acquire the time history signal of the three-dimensional aerodynamic force on each test segment.

[0015] Preferably, the base is a circular base, the wind direction angle adjustment mechanism is a high-precision turntable, and the circular base is coaxially fixed on the high-precision turntable.

[0016] Preferably, the supporting columns are provided in four groups, which are arranged symmetrically on the base.

[0017] The wind attack angle adjustment mechanism includes three transverse support rods, three pulleys, a transmission chain, and a rigid connecting rod.

[0018] One set of support columns is provided with one horizontal support rod, and another set of support columns is provided with two horizontal support rods spaced parallel to each other along the axial direction of the support columns.

[0019] Each of the transverse support rods is rotatably provided with a pulley, and the transmission chain is wound around two pulleys on the side with two transverse support rods, and the pulley on the side with only one transverse support rod is coaxially arranged with the upper pulley on the side with two transverse support rods.

[0020] The rigid connecting rod spans between the two sets of support columns. One end of the rod is fixedly connected to a pulley on the side with only one horizontal support rod, and the other end is fixedly connected to an upper pulley on the side with two horizontal support rods, so as to force the rotation angle of the pulleys on the two sets of support columns to be synchronized.

[0021] One end of the arch bridge truss model is fixedly connected to the end face of a pulley on the side with only one transverse support, and the other end is fixedly connected to the end face of a lower pulley on the side with two transverse support. Through the synchronous movement of the pulleys on the two sets of support columns, the arch bridge truss model is driven to tilt as a whole to adjust its wind attack angle.

[0022] Preferably, both ends of each of the transverse support rods are slidably sleeved on two support columns of the same group;

[0023] Each of the support columns is provided with an external thread, and a limiting nut is provided above and below the corresponding transverse support rod. The limiting nut engages with the external thread to limit the axial position of the transverse support rod on the support column, thereby adjusting the installation height of the pulley.

[0024] Preferably, the arch bridge truss model further includes at least one compensation segment, which is connected to the base via a slender force transmission rod. The slender force transmission rod is used to directly transfer the load on the corresponding compensation segment to the base, so as to avoid the load being transmitted through the test segment and interfering with the force measurement signal.

[0025] Preferably, each test segment is connected to the model support system through test segment constraints, so as to allow relative micro-amplitude vibrations between adjacent segments while transmitting the necessary constraints.

[0026] The second objective of this application is to provide a measurement method for a multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges.

[0027] The second objective of this application is achieved through the following technical solution:

[0028] A method for measuring the multi-point synchronous measurement device of buffeting load in wind tunnel testing of long-span arch bridges, the method comprising the following steps:

[0029] S1. Fix the wind direction angle adjustment mechanism to the wind tunnel test section, and fix the base on the wind direction adjustment structure. Drive the base to rotate through the wind direction angle adjustment mechanism to set the target wind direction angle;

[0030] S2. Install and adjust the model support system, and set the target wind attack angle of the arch bridge truss model;

[0031] S3. Install the arch bridge truss model and complete the mechanical connection between the two ends of the arch bridge truss model and the wind attack angle adjustment mechanism;

[0032] S4. Start the multi-channel synchronous data acquisition system, conduct wind tunnel tests under turbulent wind field conditions, and synchronously record the lift time history signal and drag time history signal of each test segment, the pitch moment time history signal of each test segment, and the incoming turbulent pulsating wind speed time history signal.

[0033] S5. Based on the lift time history signal and the incoming turbulent pulsating wind speed time history signal, the aerodynamic admittance function is directly identified through cross-spectral analysis; based on the lift time history signals of the two test segments, the spatial coherence function of the buffeting force at a distance of Δy is calculated; and based on the aerodynamic time history data of each test segment, a three-dimensional buffeting load field is constructed along the bridge span direction.

[0034] Preferably, in step S5, constructing a three-dimensional buffeting load field along the bridge span direction based on the aerodynamic time history data of each test segment specifically includes:

[0035] The aerodynamic force measured in each test segment is equivalent to a distributed load acting on a unit length strip with zero span, thereby constructing a three-dimensional flutter load field along the bridge span direction.

[0036] Preferably, in step S5, the direct identification of the aerodynamic admittance function through cross-spectral analysis specifically includes:

[0037] The cross-power spectral density between the lift time history signal and the incoming turbulent fluctuating wind speed time history signal is calculated, and combined with the self-power spectral density of the lift time history signal, the magnitude and phase characteristics of the aerodynamic admittance function are obtained.

[0038] Preferably, the method further includes: repeatedly executing steps S1 to S4 under different combinations of wind direction angle and wind attack angle to establish a buffeting load database covering the entire working range, which is used to support the refined wind-resistant design of long-span arch bridges.

[0039] Compared with the prior art, this application has the following beneficial effects:

[0040] 1. By using an embedded six-component balance and multi-channel synchronous data acquisition, the synchronous measurement of multi-point buffeting load along the span of an arch bridge was achieved for the first time;

[0041] 2. The wind direction angle and wind attack angle are independently and precisely adjustable, covering the testing needs of all operating conditions;

[0042] 3. The balance is completely concealed, and the force transmission rod is slender, minimizing disturbance to the original flow field;

[0043] 4. The height of the supporting columns is adjustable, and the installation position of the pulleys is flexible, which can be adapted to arch bridge models with different rise-to-span ratios and arch axis curvatures;

[0044] 5. It can quickly switch working conditions and generate a full working condition database to support the wind-resistant design of long-span arch bridges;

[0045] 6. This measuring device can simultaneously meet the testing requirements of segmental force measurement and structural vibration measurement. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a three-dimensional structural schematic diagram of a multi-point synchronous measurement device for buffeting load in wind tunnel testing of a long-span arch bridge according to an embodiment of this application.

[0048] Figure 2 This is a schematic diagram of the main structure of a multi-point synchronous measurement device for buffeting load in wind tunnel testing of a long-span arch bridge according to an embodiment of this application.

[0049] Figure 3 This is a schematic diagram of the installation of the force measuring unit in an embodiment of this application;

[0050] Figure 4 This is a schematic diagram of the measurement method of a multi-point synchronous measurement device for buffeting load in wind tunnel testing of a long-span arch bridge, as described in an embodiment of this application. Detailed Implementation

[0051] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] In the embodiments provided in this application, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described below are merely illustrative. For example, the division of units and modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or modules can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.

[0053] In addition, each functional unit in the various embodiments of this application can be integrated into a single processor, or each unit can be a separate device, or two or more units can be integrated into a single device; each functional unit in the various embodiments of this application can be implemented in hardware or in the form of hardware plus software functional units.

[0054] Those skilled in the art will understand that all or part of the steps of the following method embodiments can be implemented by program instructions and related hardware. The aforementioned program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, they perform the steps of the following method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0056] like Figure 1-3 As shown in the figure, this application provides a multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges. The device may include:

[0057] Base 1;

[0058] The wind direction angle adjustment mechanism 2 is fixedly connected to the lower part of the base 1, and is used to drive the base 1 to rotate around the vertical axis to set the wind direction angle.

[0059] The arch bridge truss model 3 includes two test segments 31. Each test segment 31 is equipped with a force measuring unit 4. The force measuring unit 4 includes a six-component balance 41 and a rigid force transmission structure 42. The six-component balance 41 is fixedly connected to the main load-bearing frame 311 of the corresponding test segment 31 through the rigid force transmission structure 42. The six-component balance 41 is completely embedded inside the test segment 31 and located at the geometric center of the test segment 31. There are gaps between adjacent segments of the arch bridge truss model 3 to achieve mechanical decoupling.

[0060] The model support system installed on the base 1 includes a support column 51 installed on the base 1 and a wind attack angle adjustment mechanism installed on the support column 51. The wind attack angle adjustment mechanism is connected to the arch bridge truss model 3 and is used to adjust the wind attack angle of the arch bridge truss model 3.

[0061] The multi-channel synchronous data acquisition system is electrically connected to the six-component balance 41 of all force measurement units 4. The multi-channel synchronous data acquisition system is used to synchronously acquire the time history signal of the three-dimensional aerodynamic force on each test segment 31.

[0062] In this embodiment, the base 1 serves as the overall installation platform. A wind direction angle adjustment mechanism 2 is fixedly connected below the base 1. This mechanism drives the base 1 to rotate around a vertical axis, thereby setting the horizontal wind direction angle of the arch bridge truss model 3 relative to the incoming flow. The arch bridge truss model 3 is installed on the model support system above the base 1. The arch bridge truss model 3 consists of at least two test segments 31. Each test segment 31 integrates a set of force measuring units 4. The force measuring unit 4 includes a six-component balance 41 and a rigid force transmission structure 42. The six-component balance 41 is firmly connected to the main load-bearing frame 311 of the corresponding test segment 31 through the rigid force transmission structure 42, and is completely embedded inside the segment and precisely arranged at its geometric center to ensure efficient and non-destructive aerodynamic forces. The load is transmitted to the sensor; physical gaps (1mm~3mm) are provided between adjacent test segments 31 to isolate each segment from each other in terms of force and achieve mechanical decoupling; the model support system includes support columns 51 and wind attack angle adjustment mechanisms set on them, the latter being connected to the arch bridge truss model 3 to adjust the overall pitch attitude of the arch bridge truss model 3 to set the wind attack angle; all six-component balances 41 are electrically connected to a multi-channel synchronous data acquisition system to synchronously acquire the time history signals of the three-dimensional aerodynamic forces (including lift, drag and lateral forces) and the three-dimensional moments (including roll moment, pitch moment and yaw moment) of each test segment 31 in the turbulent wind field of the wind tunnel, so as to realize multi-point, high-precision, time-aligned dynamic load measurement.

[0063] The multi-point synchronous measurement device for buffeting load in wind tunnel testing of a long-span arch bridge in this embodiment sets multiple force-measuring segments in the arch bridge truss model 3 and utilizes the gaps between segments to achieve mechanical decoupling, effectively avoiding force measurement distortion caused by structural coupling or support interference in traditional integral force measurement or external balance methods. The six-component balance 41 is completely built into the geometric center of the force-measuring segment, ensuring both the rigidity and directness of the force transmission path and eliminating the disturbance of the incoming turbulent structure by the external support, significantly improving the realism of the aerodynamic shape of the arch bridge truss model 3; multi-channel synchronous data. The acquisition system can synchronously acquire the complete six-component dynamic load time history of each measuring point in milliseconds, providing high-fidelity and highly consistent raw data for subsequent direct identification of aerodynamic admittance functions and analysis of the spatial distribution characteristics of buffeting loads along the bridge direction. The overall device realizes multi-point, synchronous, and high-precision measurement of buffeting loads of long-span arch bridges, breaking through the bottleneck of existing technologies that are difficult to capture the spatial correlation of loads in complex spatial structures. It lays a reliable experimental foundation for the refined wind-resistant design of long-span arch bridges and fundamentally solves the technical problem that traditional single-point force measurement cannot capture the spatial distribution law of loads.

[0064] In one embodiment, the base 1 is a circular base, and the wind direction angle adjustment mechanism 2 is a high-precision turntable, with the circular base coaxially fixed on the high-precision turntable.

[0065] In this embodiment, the base 1 adopts a circular base structure. The circular base is rigidly connected to the upper turntable of the high-precision turntable through a flange and high-strength bolts. The high-precision turntable serves as the wind direction angle adjustment mechanism 2. Its bottom is anchored to the ground of the wind tunnel test section through anchor bolts to ensure overall stability during rotation. Furthermore, the base 1 and the wind direction angle adjustment mechanism 2 are strictly coaxial to avoid eccentric torque.

[0066] When it is necessary to adjust the horizontal angle between the incoming flow and the bridge axis, the high-precision turntable drives the circular base to rotate smoothly around its vertical central axis, causing the entire arch bridge truss model 3 above to rotate synchronously, thereby accurately setting the target wind direction angle; the high-precision turntable has high-resolution angle feedback and closed-loop control functions, which can achieve accurate positioning and repeatable positioning at any angle.

[0067] This design enables continuous, stepless adjustment of the wind direction angle within the range of 0° to 360°, meeting the testing requirements of wind direction combinations under all working conditions. The coaxial arrangement of the circular base and the high-precision turntable ensures the stability of the system's center of gravity during rotation, avoiding additional vibrations or attitude shifts caused by eccentricity. The angular repeatability error of the high-precision turntable is less than ±0.1°, significantly improving the comparability and reliability of test data under different wind direction angles, and providing key hardware support for studying the buffeting characteristics of arch bridges under oblique wind.

[0068] In one embodiment, there are four support columns 51, which are divided into two groups. The two groups of support columns 51 are symmetrically arranged on the base 1.

[0069] The wind attack angle adjustment mechanism includes three transverse support rods 52, three pulleys 53, a transmission chain 54, and a rigid connecting rod 55, wherein,

[0070] One set of support columns 51 is provided with a horizontal support rod 52, and another set of support columns 51 is provided with two horizontal support rods 52 spaced parallel to each other along the axial direction of the support columns 51.

[0071] Each transverse support rod 52 is rotatably provided with a pulley 53, and the transmission chain 54 is wound around the two pulleys 53 on the side with two transverse support rods 52. The pulley 53 on the side with only one transverse support rod 52 is coaxially arranged with the upper pulley 53 on the side with two transverse support rods 52.

[0072] A rigid connecting rod 55 spans between two sets of support columns 51. One end of the rod is fixedly connected to a pulley 53 on the side with only one horizontal support rod 52, and the other end is fixedly connected to an upper pulley 53 on the side with two horizontal support rods 52, so as to force the rotation angle of the pulleys 53 on the two sets of support columns 51 to be synchronized.

[0073] One end of the arch bridge truss model 3 is fixedly connected to the end face of the pulley 53 on the side with only one transverse support 52, and the other end is fixedly connected to the end face of the lower pulley 53 on the side with two transverse support 52. Through the synchronous movement of the pulleys 53 on the two sets of support columns 51, the arch bridge truss model 3 is driven to tilt as a whole to adjust its wind attack angle.

[0074] In this embodiment, the four supporting columns 51 are fixed to the reserved holes on the upper surface of the base 1 by T-slot bolts at their bottoms. They are arranged symmetrically from left to right and divided into two groups. The distance between the two groups of supporting columns 51 can be adapted to the horizontal length of the arch bridge truss model 3 to be measured. One transverse support rod 52 is installed on one group of supporting columns 51, and two transverse support rods 52 are installed parallel to each other along the axial direction on the other group of supporting columns 51. Each transverse support rod 52 has a pulley 53 rotatably mounted at its end by a rolling bearing, which allows the pulley to rotate freely, forming a layout of three pulleys 53. The transmission chain 54 is wound around the chain teeth of the upper and lower pulleys 53 on the side with two transverse support rods 52, forming a closed transmission circuit and constituting a driveable chain transmission system. At the same time, the pulley 53 on the side with only one transverse support rod 52 and the upper part on the side with two transverse support rods 52 are connected. The pulleys 53 are designed as coaxial structures and are rigidly connected at their ends by a rigid connecting rod 55 spanning the two supporting columns 51 on both sides, through a keyway and set screw, thereby forcing them to maintain the same rotation angle. One end of the arch bridge truss model 3 is fixedly connected to the end face of the pulley 53 on the side of the single transverse support 52, and the other end is fixedly connected to the end face of the lower pulley 53 on the side of the double transverse support 52. When the transmission chain 54 is driven, the upper and lower pulleys 53 on the side of the double transverse support 52 rotate in the same direction. Since the upper pulley 53 on the side of the double transverse support 52 and the pulley 53 on the side of the single transverse support 52 are coaxially linked through the rigid connecting rod 55, the pulley 53 on the side of the single transverse support 52 rotates synchronously, resulting in a vertical height difference between the two ends of the arch bridge truss model 3, thereby driving the entire arch bridge truss model 3 to rigidly tilt around the rotation direction of the pulley 53, achieving precise adjustment of the wind attack angle.

[0075] This embodiment achieves coordinated movement at both ends of the arch bridge truss model 3 through the coordinated operation of three pulleys 53, transmission chain 54, and rigid connecting rod 55, requiring only unilateral drive (transmission chain 54). This ensures that the arch bridge truss model 3 pitches as a rigid body, avoiding twisting or local stress concentration caused by asynchronous rotation. The coaxial arrangement and rigid connecting rod 55 effectively guarantee the consistency of the rotation angle of the pulleys 53 on both sides, improving the accuracy and repeatability of wind attack angle adjustment. The arch bridge truss model 3 is directly fixed to the end face of the pulleys 53, resulting in a short and rigid force transmission path, reducing gap errors and hysteresis effects during adjustment. The overall structure is compact and mechanically reliable, enabling stable operation in strong airflow environments in wind tunnels, meeting the requirements for rapid, accurate, and disturbance-free adjustment of wind attack angle in wind tunnel tests of large-span arch bridges.

[0076] The wind attack angle adjustment mechanism in this embodiment can cover common working conditions of long-span arch bridges. The whole system adopts pure mechanical linkage without the need for an additional servo system, which improves the reliability and anti-interference ability of the device, while ensuring the accuracy and repeatability of the wind attack angle setting.

[0077] In some other embodiments, the chain drive system consisting of pulley 53 and drive chain 54 can also be automatically driven by a drive device (not shown in the figure) connected to one of the pulleys 53, and a locking mechanism (not shown in the figure) can be set to lock and limit one of the pulleys 53 when the wind attack angle is adjusted to the correct position.

[0078] This embodiment introduces automated drive and mechanical locking functions based on the aforementioned chain-driven wind attack angle adjustment mechanism. The drive device (such as a servo motor or stepper motor) establishes a transmission connection with any pulley 53 in the chain drive system (e.g., the upper pulley 53 on the side of the double transverse support rod 52) through a coupling or reduction gearbox. When the control system issues a wind attack angle setting command, the drive device outputs rotational motion, driving the pulley 53 to rotate, which in turn drives another pulley 53 to rotate through the transmission chain 54. At the same time, the rigid connecting rod 55 forces the pulley 53 on one side to rotate synchronously, ultimately creating a height difference between the two ends of the arch bridge truss model 3, achieving overall pitch to reach the target wind attack angle. When the angle sensor (such as an encoder or inclinometer) reports that the current wind attack angle has reached the set value, the control system controls the drive device to stop running and triggers the locking mechanism to lock the shaft of the selected pulley 53 (e.g., the drive pulley 53), preventing it from rotating or swaying slightly under the strong airflow in the wind tunnel, thereby ensuring the long-term stability of the arch bridge truss model 3's attitude during the test.

[0079] Specifically, in this embodiment, the driving device can be a high-precision servo motor, which is installed on the outside of the support column 51 or on the base 1, and the output shaft is connected to the end of the rotating shaft of the upper pulley 53 on the side of the double transverse support rod 52 through a flexible coupling.

[0080] An angle sensor can be an absolute rotary encoder integrated on the shaft of pulley 53 to monitor the rotation angle in real time and feed it back to the control system.

[0081] The locking mechanism may include an electromagnetic brake or a mechanical pin device: if an electromagnetic brake is used, its stator is fixed to the support column 51, and its rotor is coaxially connected to the shaft of the pulley 53, releasing when energized and holding when de-energized; if a mechanical pin is used, the pin is driven by a cylinder or electric push rod to be inserted radially into the positioning hole on the hub of the pulley 53 to achieve physical limiting.

[0082] The control system can be composed of an industrial computer or a PLC, which receives the wind angle of attack value set by the user, controls the operation of the servo motor, and automatically triggers the locking mechanism to act when the position is reached.

[0083] This embodiment significantly improves the intelligence and reliability of wind angle of attack adjustment by introducing servo drive and active locking mechanism: on the one hand, the servo motor, in conjunction with closed-loop control, can achieve high-precision angle positioning within ±0.05°, supporting programmed batch tests or continuous angle scanning, greatly improving the efficiency of wind tunnel tests; on the other hand, the locking mechanism implements rigid limit on the key pulley 53 after adjustment, effectively suppressing the slight rebound or vibration drift that may occur under strong wind load, ensuring the constancy of the attitude of the arch bridge truss model 3 during long-term sampling, thereby improving the signal-to-noise ratio and repeatability of the force measurement data; in addition, automated operation reduces manual intervention and lowers the risk of human error, making it particularly suitable for wind resistance research scenarios of large-span arch bridges that require full-condition matrix tests or high-precision parameter identification.

[0084] In one embodiment, each transverse support rod 52 has through holes at both ends, and the through holes at both ends are respectively fitted onto the outer walls of two support columns 51 in the same group, and can slide freely in the axial direction of the support columns.

[0085] Each support column 51 is provided with an external thread, and a limiting nut 56 is provided above and below the corresponding transverse support rod 52. The limiting nut 56 engages with the external thread to limit the axial position of the transverse support rod 52 on the support column 51, thereby adjusting the installation height of the pulley 53. After the upper and lower limiting nuts 56 are screwed into the external thread, they clamp the transverse support rod 52, thereby achieving reliable locking of the installation height of the pulley 53.

[0086] In this embodiment, each transverse support rod 52 is slidably sleeved on two supporting columns 51 in the same group at both ends. The surface of the supporting columns 51 is machined with external threads, and a limiting nut 56 is set above and below the transverse support rod 52. By loosening the limiting nut 56, the transverse support rod 52 can be moved along the column axis to adjust its height, and then the nut can be tightened again to fix the position. This structure allows the installation height of the pulley 53 to be flexibly adjusted according to the size of the arch bridge truss model 3 or the geometric characteristics of the arch axis.

[0087] This design significantly enhances the adaptability and versatility of the device, enabling it to be quickly adapted to large-span arch bridge models with different span-to-rise ratios or heights without requiring replacement of the support structure. The threaded-nut fit provides a stable axial limit, ensuring that the pulley 53 position remains unchanged even under strong wind loads, thus guaranteeing the long-term stability of the wind attack angle adjustment. The height-adjustable mechanism also makes it possible to simulate asymmetric arch shapes or local linear changes, enhancing the device's application potential in the wind engineering research of complex bridges.

[0088] In one embodiment, the arch bridge truss model 3 further includes three compensation segments 32. Each compensation segment 32 has a lug plate welded to its critical stress points. One end of a slender force transmission rod 6 is connected to the lug plate via a pin and a spherical bearing, while the other end is anchored to the base 1 via a ball joint support, allowing for slight rotation to avoid additional bending moments, while directly transferring vertical and horizontal loads to the base. The slender force transmission rod 6 is used to directly transfer the load on the corresponding compensation segment 32 to the base 1, so as to avoid the load being transmitted through the test segment 31 and interfering with the force measurement signal.

[0089] In this embodiment, in addition to the test segment 31, the arch bridge truss model 3 also includes three compensation segments 32. The compensation segments 32 do not have force measuring units 4 installed, but are directly connected to the base 1 through slender force transmission rods 6. The slender force transmission rods 6 are usually high-strength steel rods with a small diameter. One end is fixed to the key node of the compensation segment 32, and the other end is anchored to the base 1. The self-weight and wind load of the compensation segment 32 are directly transmitted to the base 1 through the rod, forming a force transmission path independent of the test segment 31.

[0090] This design effectively isolates the force measurement system from interference from non-test areas, ensuring that the six-component balance 41 only senses the real aerodynamic forces of its segment, avoiding force measurement distortion caused by load crosstalk; the slender force transmission rod 6 has a small cross-section and is concealed, minimizing obstruction and disturbance to the incoming turbulent structure, thus preserving the natural characteristics of the flow field to the maximum extent; at the same time, this rod provides the necessary structural support for the compensation segment 32, maintaining the overall geometric stability of the arch bridge truss model 3.

[0091] Specifically, such as Figure 1 As shown, in this embodiment, the arch bridge truss model 3 consists of two test segments 31 and three compensation segments 32, and is arranged in an alternating manner, that is, each test segment 31 is sandwiched between two compensation segments 32, forming a five-segment layout of "non-test - test - non-test - test - non-test". In this arrangement, the two test segments 31 are physically isolated in space by the compensation segment 32 and are not adjacent to each other. The distance Δy between them is the arc length distance from the center of one test segment 31 to the center of the other test segment 31 along the arch axis. Small gaps are provided between all segments to achieve mechanical decoupling. The compensation segment 32 directly transmits its load to the base 1 through the slender force transmission rod 6, avoiding the load from flowing through the test segment 31. A six-component balance 41 is independently installed inside each test segment 31 and connected to the support system through the test segment constraint 7, which allows for local micro-vibration while ensuring structural stability. During the wind tunnel test, the multi-channel synchronous data acquisition system synchronously acquires the lift, drag and pitch moment time history signals of the two test segments 31 for subsequent aerodynamic parameter identification.

[0092] This arrangement effectively simulates the typical stress state of the main arch rib of a long-span arch bridge far from the end constraints in actual wind fields by symmetrically embedding two test segments 31 into the middle of the non-test area. This avoids boundary effect interference and improves the representativeness of the measurement data. At the same time, the large segment spacing Δy (which can cover 1 / 4 to 1 / 2 of the arch span) makes the calculated spatial coherence function of the buffeting force better reflect the attenuation characteristics of the load over medium and long distances, providing key data for establishing a high-precision spatial correlation arch bridge truss model 3. The isolation effect of the compensation segment 32 further enhances the independence of the force measurement system, ensuring that the signals from the two measurement points do not interfere with each other. The overall layout takes into account structural integrity, aerodynamic realism, and measurement science, and is particularly suitable for studying the spatial distribution law and span coherence characteristics of buffeting loads in long-span arch bridges.

[0093] In one embodiment, each test segment 31 is connected to the model support system via a test segment constraint 7, allowing adjacent segments to generate relatively small vibrations while transmitting necessary constraints. The main frame of the test segment 31 is provided with a connecting lug, and one end of the test segment constraint 7 is fixed to the connecting lug by bolts, while the other end is fixed to the bracket on the corresponding pulley end face.

[0094] In this embodiment, each test segment 31 is not rigidly fixed to the support system, but is connected to the model support system through test segment constraint members 7 (such as helical springs, flexible hinges or rubber pads); these test segment constraint members 7 provide sufficient static stiffness to maintain the overall shape of the arch bridge truss model 3, while allowing the test segments 31 to generate micro-amplitude relative vibrations under wind-induced excitation, with the amplitude usually controlled within the millimeter level.

[0095] It should be noted that when the measuring device is used for force measurement experiments on test segments, the test segment constraint 7 adopts a rigid connecting rod; when the measuring device is used for vibration measurement experiments on arch bridge truss model structures, the test segment constraint 7 adopts an elastic connecting member.

[0096] During vibration measurement experiments, the test segment constraint 7 uses a flexible connection method with elastic connectors to more realistically simulate the dynamic coupling characteristics between local components in an actual long-span arch bridge, avoiding the over-constraint problem and non-physical stress concentration caused by completely rigid constraints. The micro-amplitude vibration capability enables the arch bridge truss model 3 to exhibit dynamic response behavior closer to the prototype in the wind tunnel, improving the dynamic similarity of the experiment. In addition, this design reserves an interface for future expansion to synchronously measure displacement or acceleration response, which is convenient for carrying out force-displacement coupling analysis or verifying numerical models, enhancing the versatility and forward-looking nature of the device in the study of complex wind-induced vibration mechanisms.

[0097] In one embodiment, Figure 1-3The multi-point synchronous measurement device for buffeting loads used in wind tunnel testing of long-span arch bridges, as shown, adopts a bottom-up modular installation process, mainly including five steps: base construction, model support system installation, arch bridge truss model main body assembly, segmented arch bridge truss model connection, and internal force measuring unit installation.

[0098] 1. Base installation: Fix the high-precision turntable to the wind tunnel test section, and fix the circular base on the high-precision turntable. The horizontal wind direction angle of the arch bridge truss model 3 relative to the incoming flow can be set by driving the circular base to rotate through the high-precision turntable.

[0099] 2. Model Support System Installation: Based on the span coordinates of the designed arch axis, install two sets (two columns per set) of vertical support columns 51 symmetrically on the left and right sides of the reserved holes in the base; install two sets of horizontal support rods 52 (three in total, two on the left side (installed alternately vertically) and one on the right side) on the two sets of support columns 51 respectively, and install a pulley 53 on each horizontal support rod 52. A transmission chain 54 is wound around the two pulleys 53 on the left side. The upper pulley 53 on the left side and the pulley 53 on the right side are set at the same horizontal height and coaxially, and are connected by a rigid connecting rod 55; rotate the pulleys 53 to set the target wind attack angle of the arch bridge truss model 3;

[0100] 3. End connection of the arch bridge truss model: The two compensation segments 32 at both ends of the arch bridge truss model 3 are rigidly connected to the end faces of the pulleys 53 on both sides respectively. At the same time, the load of each non-test segment is directly transferred to the base 1 through two slender force transmission rods 6 to avoid interfering with the force measurement signal.

[0101] 4. Hoisting of intermediate sections of the arch bridge truss model: The intermediate sections of the arch bridge truss model 3 are hoisted sequentially along the span direction, including two test sections 31 and one compensation section 32. The compensation section 32 directly transmits the load of the non-test section to the base 1 through two slender force transmission rods 6. Each test section 31 is connected to the end face of the pulley 53 of the model support system through at least two test section constraint members 7, so as to allow relative micro-vibration of adjacent sections while transmitting necessary constraints. A small gap is reserved between adjacent sections to ensure mechanical decoupling.

[0102] 5. Installation of force measuring unit: A six-component balance 41 is installed inside the geometric center of each test segment 31. The balance is rigidly connected to the main load-bearing frame 311 of the truss through a rigid force transmission structure 42 and is completely enclosed by the outer shell of the arch bridge truss model 3 to achieve internal force measurement.

[0103] In one embodiment, Figure 1-3 The wind tunnel test implementation method of the multi-point synchronous measurement device for buffeting load used in wind tunnel testing of long-span arch bridges is as follows:

[0104] Before the experiment began, the installation heights on both sides of the arch bridge truss model were first determined, and the base installation position was determined based on the dimensions of the wind tunnel test section and the flow field characteristics. Then, all mechanical and electrical connections were completed. The specific operation procedure is as follows:

[0105] Adjust the height of each pulley according to the determined installation height on both sides of the arch bridge truss model;

[0106] The target wind direction angle is set using a high-precision turntable;

[0107] Drive the pulley to rotate and set the target wind angle of attack;

[0108] Start the multi-channel synchronous data acquisition system (sampling rate ≥ 1kHz) and record synchronously in the passively or actively generated turbulent wind field:

[0109] Lift time history, drag time history, and pitching moment time history for each test segment;

[0110] Incoming longitudinal pulsating wind speed time history (obtained by a high-frequency anemometer);

[0111] All test segments are connected to the support system through rigid test segment constraints, thereby ensuring that the test segments are constrained and fixed.

[0112] This device constructs a discrete spatial force monitoring network by arranging independent force measuring points at different positions on the arch ribs, which can directly obtain the distribution characteristics of the flutter load along the bridge span and its unsteady evolution law.

[0113] This application also provides a basic embodiment. Figure 1-3 The method shown is a method for reconstructing the buffeting load field from measured data of a multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges. Taking the axis of a catenary arch as an example, this method directly identifies aerodynamic parameters and reconstructs the three-dimensional buffeting load field based on measured data. The specific steps are as follows:

[0114] Step 1: Identification of spatial coherence function of chattering force

[0115] 1.1 Using a six-component balance of two test segments, the time history signals of the buffing lift, buffing resistance, and buffing torque at the two locations are acquired simultaneously.

[0116] 1.2 Fourier transforms were performed on the time-history signals of the buffeting force for each test segment to calculate the buffeting force point spectrum for the two test segments. ,in These represent buffet lift, buffet drag, and buffet lift torque, respectively. For downstream wave number;

[0117] 1.3 Calculate the cross-power spectral density between the two measurement points to obtain the wavenumber coherence function at a spacing of Δy. The distance Δy is taken as the arc length between two measurement points, and then the coherence function of the test segment is evaluated using an empirical coherence function model. The measured values ​​are fitted, and the principle is shown in Equations 1 to 3:

[0118] (Formula 1)

[0119] (Formula 2)

[0120] (Formula 3)

[0121] in, These represent buffet lift, buffet drag, and buffet lift torque, respectively. , , The fitting parameters are dimensionless. The integral scale for turbulence in the wind field. and It is a constant related to the geometric dimensions or mechanical properties (tension to weight ratio) of the structure. , These are the horizontal coordinates of the two points spanning the distance;

[0122] 1.4. Based on the fitting results of the measured values ​​of the coherence function, derive the coherence function of the two wavenumbers. :

[0123] (Formula 4)

[0124] in, This indicates the wave number along the length (span) of the model.

[0125] Step 2: Constructing the equivalent load field per unit length strip

[0126] Through steps 1.1 to 1.4 above, the length is obtained as follows: To obtain the three-dimensional buffeting load distributed along the span direction of the entire arch bridge truss model, the buffeting force parameters on the test segment of the arch bridge need to be obtained by passing a test segment of length [missing information]. The chattering force parameter on the test segment is equivalent to the chattering force parameter on a unit length strip with zero span. The method steps are as follows:

[0127] 2.1, Based on aerodynamic theory, establish a length of... The relationship between the coherence function of the test segment and the coherence function of a unit-length strip with zero span:

[0128] (Formula 5)

[0129] in, It is the Singer function; superscript This represents a strip of length per unit length with a span of 0. For a unit length strip with zero span, the wavenumber chattering force coherence function is given. The fitting parameters and their relationship are shown in Equations 6 to 8:

[0130] (Formula 6)

[0131] (Formula 7)

[0132] (Formula 8)

[0133] in, These represent buffet lift, buffet drag, and buffet lift torque, respectively. , , The fitting parameters are dimensionless. These are dimensionless fitting parameters;

[0134] Therefore, the dimensionless fitting parameters It is possible to obtain the two-wavenumber coherence function for a unit length strip with a span of 0. As shown in Formula Nine:

[0135] (Formula 9)

[0136] 2.2 Using the fitting parameters from step 1 and combining them with the above relationships, the fitting parameters for the coherence function of a unit length strip with a span of 0 are obtained by inversion. Undetermined parameters in;

[0137] 2.3 Establishing the chattering force spectrum of the test segment The force spectrum of a unit length strip with a span of 0 The mathematical relationship between them:

[0138] (Formula 10)

[0139] 2.4, the buffeting force spectrum of the test segment. Fitting parameters of the coherence function for unit length strips with zero span obtained by inversion Substituting into Formula 10, we finally obtain the flutter force spectrum of a unit length strip with a span of 0. .

[0140] Step 3, Representation of the three-dimensional buffeting load field

[0141] The three-dimensional buffeting load distributed along the entire span of the test beam segment is represented as a buffeting force spectrum per unit length of a strip with zero span. Its chattering force and two-wavenumber coherence function The product is in the form shown below:

[0142] (Formula 11)

[0143] in, express Two wavenumber spectra.

[0144] This expression fully describes the unsteady characteristics of buffeting loads in the time-space frequency domain and can be directly used for refined wind resistance analysis of long-span arch bridges.

[0145] like Figure 4 As shown in the embodiment of this application, a method for multi-point synchronous measurement of buffeting load for wind tunnel testing of long-span arch bridges is provided. This method may include the following steps:

[0146] S1, fix the wind direction angle adjustment mechanism to the wind tunnel test section, and fix the base on the wind direction adjustment structure. Drive the base to rotate through the wind direction angle adjustment mechanism to set the target wind direction angle;

[0147] S2, Install and adjust the model support system, and set the target wind attack angle of the arch bridge truss model;

[0148] S3, Install the arch bridge truss model and complete the mechanical connection between the two ends of the arch bridge truss model and the wind attack angle adjustment mechanism;

[0149] S4, start the multi-channel synchronous data acquisition system, conduct wind tunnel tests under turbulent wind field conditions, and synchronously record the lift time history signal and drag time history signal of each test segment, the pitch moment time history signal of each test segment, and the incoming turbulent pulsating wind speed time history signal.

[0150] S5. Based on the lift time history signal and the incoming turbulent fluctuating wind speed time history signal, the aerodynamic admittance function is directly identified through cross-spectral analysis; based on the lift time history signals of two test segments, the spatial coherence function of the buffeting force at a distance of Δy is calculated; and based on the aerodynamic time history data of each test segment, a three-dimensional buffeting load field along the bridge span direction is constructed.

[0151] In this embodiment of the multi-point synchronous measurement method for buffeting load in wind tunnel testing of long-span arch bridges, the wind direction angle adjustment mechanism is first fixed to the ground of the wind tunnel test section, and the base is installed on the adjustment mechanism. The target wind direction angle is set by driving the base to rotate around the vertical axis. Then, the model support system is installed and adjusted to adjust the overall pitch attitude of the arch bridge truss model to set the target wind attack angle. Next, the arch bridge truss model is installed, and its two ends are rigidly mechanically connected to the wind attack angle adjustment mechanism to ensure effective transmission of force and displacement. Under turbulent wind field conditions, the multi-channel synchronous data acquisition system is started to synchronously acquire data from each test segment. The system collects lift time history signals, drag time history signals, pitching moment time history signals, and incoming turbulent fluctuating wind speed time history signals. Finally, based on the collected synchronous data, three core processing steps are performed: First, cross-spectral analysis is performed using the lift time history signals and the incoming turbulent fluctuating wind speed time history signals to directly identify the aerodynamic admittance function; second, based on the lift time history signals of any two test segments, the spatial coherence function of the buffeting force under the condition of a spacing of Δy is calculated; third, by integrating the aerodynamic time history data of all test segments, a three-dimensional buffeting load field is constructed along the bridge span direction, thereby realizing the mapping from discrete measuring points to continuous spatial load distribution.

[0152] This method, for the first time, achieves an integrated process of multi-point synchronous force measurement, synchronous wind measurement, direct aerodynamic parameter identification, and spatial load field reconstruction in wind tunnel tests of long-span arch bridges, breaking through the traditional indirect identification mode that relies on structural response to infer aerodynamic forces. By synchronously recording lift, drag, pitching moment, and incoming wind speed, it can not only identify aerodynamic admittance with high precision but also quantitatively characterize the spatial correlation of buffeting loads along the bridge direction. The constructed three-dimensional buffeting load field can realistically reflect the unsteady characteristics of the load in time and space dimensions, providing high-fidelity input for the buffeting response simulation of long-span arch bridges. The entire method has a rigorous logical process and strong data self-consistency, significantly improving the scientificity, accuracy, and engineering applicability of wind load identification for complex spatial bridge structures.

[0153] In one embodiment, step S5, which involves constructing a three-dimensional buffeting load field along the bridge span direction based on the aerodynamic time history data of each test segment, specifically includes:

[0154] The aerodynamic force measured in each test segment is equivalent to a distributed load acting on a unit length strip with zero span, thereby constructing a three-dimensional flutter load field along the bridge span direction.

[0155] The equivalent method in this embodiment is based on the "strip hypothesis" in aerodynamic theory, which assumes that the resultant force on each finite-length test segment can be regarded as a distributed load concentrated on an infinitely narrow (zero-span) two-dimensional aerodynamic strip at its geometric center, thereby mapping discrete measurement point data into a continuous spatial function.

[0156] This equivalent strategy effectively bridges the gap between the discreteness of physical measurement points and the continuous load field required by engineering, enabling a limited number of force measurement segments to extrapolate and characterize the spatial distribution of the entire span buffeting load. The "unit length strip" model conforms to the classical aerodynamic admittance theory framework and is easy to interface with existing wind vibration analysis software (such as ANSYS and Midas). At the same time, this method preserves the time-frequency characteristics and spatial location information of the load, and the constructed three-dimensional buffeting load field can be directly used for time-domain buffeting response simulation or frequency-domain power spectrum analysis, significantly improving the scientificity and reliability of the wind-resistant design of long-span arch bridges.

[0157] In one embodiment, step S5, which involves directly identifying the aerodynamic admittance function through cross-spectral analysis, specifically includes:

[0158] The cross-power spectral density between the lift time history signal and the incoming turbulent fluctuating wind speed time history signal is calculated, and combined with the self-power spectral density of the lift time history signal, the magnitude and phase characteristics of the aerodynamic admittance function are obtained.

[0159] In this embodiment, when directly identifying the aerodynamic admittance function through cross-spectral analysis, the lift and longitudinal pulsating wind speed of the synchronously acquired data are first subjected to Fourier transform to obtain the frequency domain signal; then the cross-power spectrum of the two, as well as the lift self-power spectrum and the wind speed self-power spectrum are calculated; finally, according to the definition of aerodynamic admittance, its complex form is solved, and the magnitude and phase are then separated.

[0160] This direct identification method does not rely on the vibration response or modal parameters of the bridge structure, avoiding the uncertainties introduced by structural damping and frequency identification errors in indirect methods. By simultaneously measuring wind speed and aerodynamic forces at a high sampling rate, the accuracy of frequency domain analysis is ensured. The resulting aerodynamic admittance function contains complete amplitude and phase frequency information, which can truly reflect the unsteady aerodynamic characteristics of the arch bridge section under turbulent excitation. The results can be directly used to correct the Scanlan buffeting force formula, significantly improving the accuracy of buffeting response prediction for long-span arch bridges and providing key parameter support for wind resistance safety assessment.

[0161] In one embodiment, the measurement method further includes: repeatedly executing steps S1 to S4 under different combinations of wind direction angle and wind attack angle to establish a buffeting load database covering the entire working range, which is used to support the refined wind-resistant design of long-span arch bridges.

[0162] Specifically, by systematically traversing the combination of typical wind direction angles (such as 0°, 15°, 30°…90°) and wind attack angles (such as −6°, −3°, 0°, +3°, +6°), a complete measurement process is performed for each working condition to obtain the corresponding aerodynamic admittance, spatial coherence function and three-dimensional buffeting load field, and all data are structured and stored in the database.

[0163] This database comprehensively covers the wind environment combinations that long-span arch bridges may encounter in actual service, providing data-driven support for wind-resistant design. Engineers can quickly retrieve load data for corresponding working conditions based on the wind rose diagram of a specific bridge site, avoiding over-design caused by conservative assumptions. At the same time, the database can be used to train machine learning models to achieve rapid prediction of aerodynamic parameters or interpolation of missing working conditions. In addition, the database also supports parameter sensitivity analysis, revealing the influence of wind direction angle and wind attack angle on the spatial distribution of buffeting loads, providing a scientific basis for optimizing the aerodynamic shape of arch bridges, and significantly improving the refinement and intelligence level of wind-resistant design for long-span arch bridges.

[0164] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0165] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0166] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly using hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0167] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. 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 this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges, characterized in that, The device includes: Base; A wind direction angle adjustment mechanism is fixedly connected to the lower part of the base, which is used to drive the base to rotate around the vertical axis to set the wind direction angle; An arch bridge truss model includes at least two test segments. Each test segment contains a force measuring unit, which includes a six-component balance and a rigid force transmission structure. The six-component balance is fixedly connected to the main load-bearing frame of the corresponding test segment through the rigid force transmission structure. The six-component balance is completely embedded inside the test segment and located at the geometric center of the test segment. There are gaps between adjacent segments of the arch bridge truss model to achieve mechanical decoupling. The model support system installed on the base includes a support column installed on the base and a wind attack angle adjustment mechanism disposed on the support column. The wind attack angle adjustment mechanism is connected to the arch bridge truss model and is used to adjust the wind attack angle of the arch bridge truss model. A multi-channel synchronous data acquisition system is electrically connected to a six-component balance of all force measurement units. The multi-channel synchronous data acquisition system is used to synchronously acquire the time history signal of the three-dimensional aerodynamic force on each test segment.

2. The multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges according to claim 1, characterized in that, The base is a circular base, and the wind direction angle adjustment mechanism is a high-precision turntable. The circular base is coaxially fixed on the high-precision turntable.

3. The multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges according to claim 1, characterized in that, The support columns are provided in four units, which are divided into two groups. The two groups of support columns are symmetrically arranged on the base. The wind attack angle adjustment mechanism includes three transverse support rods, three pulleys, a transmission chain, and a rigid connecting rod. One set of support columns is provided with one horizontal support rod, and another set of support columns is provided with two horizontal support rods spaced parallel to each other along the axial direction of the support columns. Each of the transverse support rods is rotatably provided with a pulley, and the transmission chain is wound around two pulleys on the side with two transverse support rods, and the pulley on the side with only one transverse support rod is coaxially arranged with the upper pulley on the side with two transverse support rods. The rigid connecting rod spans between the two sets of support columns. One end of the rod is fixedly connected to a pulley on the side with only one horizontal support rod, and the other end is fixedly connected to an upper pulley on the side with two horizontal support rods, so as to force the rotation angle of the pulleys on the two sets of support columns to be synchronized. One end of the arch bridge truss model is fixedly connected to the end face of a pulley on the side with only one transverse support, and the other end is fixedly connected to the end face of a lower pulley on the side with two transverse support. Through the synchronous movement of the pulleys on the two sets of support columns, the arch bridge truss model is driven to tilt as a whole to adjust its wind attack angle.

4. The multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges according to claim 3, characterized in that, Each of the transverse support rods is slidably sleeved at both ends onto two support columns in the same group; Each of the support columns is provided with an external thread, and a limiting nut is provided above and below the corresponding transverse support rod. The limiting nut engages with the external thread to limit the axial position of the transverse support rod on the support column, thereby adjusting the installation height of the pulley.

5. The multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges according to claim 1, characterized in that, The arch bridge truss model also includes at least one compensation segment, which is connected to the base via a slender force transmission rod. The slender force transmission rod is used to directly transfer the load on the corresponding compensation segment to the base, so as to avoid the load being transmitted through the test segment and interfering with the force measurement signal.

6. The multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges according to claim 1, characterized in that, Each test segment is connected to the model support system through test segment constraints to allow for relative micro-vibrations between adjacent segments while transmitting necessary constraints.

7. A measurement method for a multi-point synchronous measurement device for buffeting load in wind tunnel testing of long-span arch bridges as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Fix the wind direction angle adjustment mechanism to the wind tunnel test section, and fix the base on the wind direction adjustment structure. Drive the base to rotate through the wind direction angle adjustment mechanism to set the target wind direction angle; S2. Install and adjust the model support system, and set the target wind attack angle of the arch bridge truss model; S3. Install the arch bridge truss model and complete the mechanical connection between the two ends of the arch bridge truss model and the wind attack angle adjustment mechanism; S4. Start the multi-channel synchronous data acquisition system, conduct wind tunnel tests under turbulent wind field conditions, and synchronously record the lift time history signal and drag time history signal of each test segment, the pitch moment time history signal of each test segment, and the incoming turbulent pulsating wind speed time history signal. S5. Based on the lift time history signal and the incoming turbulent pulsating wind speed time history signal, the aerodynamic admittance function is directly identified through cross-spectral analysis; based on the lift time history signals of the two test segments, the spatial coherence function of the buffeting force at a distance of Δy is calculated; and based on the aerodynamic time history data of each test segment, a three-dimensional buffeting load field is constructed along the bridge span direction.

8. The measurement method according to claim 7, characterized in that, In step S5, the construction of a three-dimensional buffeting load field along the bridge span direction based on the aerodynamic time history data of each test segment specifically includes: The aerodynamic force measured in each test segment is equivalent to a distributed load acting on a unit length strip with zero span, thereby constructing a three-dimensional flutter load field along the bridge span direction.

9. The measurement method according to claim 7, characterized in that, In step S5, the direct identification of the aerodynamic admittance function through cross-spectral analysis specifically includes: The cross-power spectral density between the lift time history signal and the incoming turbulent fluctuating wind speed time history signal is calculated, and combined with the self-power spectral density of the lift time history signal, the magnitude and phase characteristics of the aerodynamic admittance function are obtained.

10. The measurement method according to claim 7, characterized in that, The method further includes: repeatedly executing steps S1 to S4 under different combinations of wind direction angle and wind attack angle to establish a buffeting load database covering the entire working range, which is used to support the refined wind-resistant design of long-span arch bridges.

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