A liquid anti-sloshing and vibration isolation integrated system for laying GIL pipes with bridges

Abstract

The present application belongs to the technical field of gas insulated metal enclosed transmission line (GIL) bridge laying, and particularly relates to a GIL suspension system laid along the bottom of a bridge and integrated with multi-grade vibration reduction and self-monitoring, which can be applied to GIL power transmission projects of large-span bridges across rivers or seas. The present application provides a liquid anti-sloshing vibration reduction and piezoelectric monitoring integrated system for GIL pipes laid along a bridge, which solves the problems of poor deformation adaptability, obvious wind-induced sloshing, narrow vibration isolation frequency band, insufficient self-vibration suppression and complex state monitoring of the existing GIL bridge laying support system, realizes four-stage collaborative vibration reduction of "hinged energy release-tuned anti-sloshing-elastic vibration isolation-damping vibration suppression", and realizes self-driven monitoring of the vibration state by using the liquid sloshing of the anti-sloshing tank to drive the piezoelectric unit.

Description

Technical Field

[0001] This invention belongs to the technical field of gas insulated metal-enclosed transmission line (GIL) bridge-laying technology, specifically involving a suspended GIL system that integrates multi-level vibration reduction and isolation with self-monitoring of operating status, which can be applied to GIL transmission projects of long-span bridges across rivers and seas. Background Technology

[0002] With the continuous increase in power transmission capacity and the advancement of cross-river and cross-sea power transmission channel construction, gas-insulated transmission lines (GILs) have gradually become the preferred solution for long-span bridge-crossing power transmission projects due to their advantages such as large transmission capacity, high operational stability, strong resistance to electromagnetic interference, and small footprint. Adopting the GIL-laying method along the bridge can fully utilize the space resources under the bridge, reduce the occupation of the line corridor, lower project investment, and has good prospects for engineering application.

[0003] Currently, GIL (Gas Insulator) pipelines laid along bridges typically employ methods such as hangers, supports, or elastic bracing to suspend or fix the pipelines to the lower part of the bridge structure. Existing vibration reduction and isolation measures mainly include rigid supports, ordinary elastic bearings, and simple damping elements, achieving pipeline load-bearing and a certain degree of vibration isolation through the support structure. However, most existing technologies only focus on the static load-bearing capacity or single-stage vibration reduction function of the GIL pipeline, exhibiting significant deficiencies in adapting to multi-field coupled vibrations in the complex environment of bridges. Specifically, the following technical shortcomings exist: First, most existing support structures adopt rigid connections or single-stage elastic vibration reduction, which have limited vibration reduction and isolation levels. They are not effective in isolating broadband vibrations caused by vehicle loads, wind loads, and earthquakes. Bridge vibrations can easily be transmitted directly to the pipeline system through the support structure, causing GIL pipeline vibrations to exceed the standard and affecting its operational stability and insulation life. Secondly, bridges will experience vertical deflection, lateral displacement, and spatial rotation deformation under temperature changes, vehicle loads, and wind loads. The existing support structure is not capable of releasing multi-directional displacement and rotation deformation, which can easily create additional constraints on the GIL pipeline and generate large additional stress inside the pipeline. Under long-term operation, this may lead to failure of the pipeline flange seal or structural fatigue damage. Third, existing suspension support systems generally lack targeted wind-resistant and vibration-damping measures. Under the action of transverse wind loads, long-distance suspended GIL pipes and support platforms are prone to significant lateral swaying or even vortex-induced resonance, which not only reduces the stability of the support system but may also further induce coupled vibration between the pipe and the bridge. Fourth, most existing vibration reduction devices only control external vibrations transmitted by bridges and lack effective energy dissipation mechanisms for mechanical vibrations and electromagnetic excitation vibrations generated by the GIL itself during operation, making it difficult to continuously suppress high-frequency micro-vibrations in pipelines. Fifth, the existing GIL system laid along the bridge requires additional installation of acceleration sensors, displacement sensors and other equipment for condition monitoring, which has problems such as complex power supply wiring, high cost and high maintenance difficulty. In addition, it cannot use the movement of the vibration reduction structure itself to achieve self-driven acquisition of monitoring signals, making it difficult to achieve integrated vibration reduction and condition monitoring. Sixth, existing tuned liquid dampers (TLDs) are used only as a single vibration damping component, requiring additional sensors to monitor their operating status. They do not fully utilize the mechanical energy of liquid sloshing to achieve self-driven monitoring, resulting in limited functionality and low system integration.

[0004] Therefore, there is an urgent need in the industry to develop an integrated system for anti-swaying, vibration isolation, pipeline vibration suppression and vibration monitoring of GIL pipelines laid along bridges. This system should be able to adapt to large bridge deformations, suppress wind-induced swaying, isolate vibration transmitted by the bridge, absorb the pipeline's own vibration, and utilize the movement of the vibration reduction structure itself to achieve self-monitoring of its condition, thereby comprehensively improving the operational safety and reliability of GIL systems laid along bridges. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing an integrated liquid anti-sloshing vibration reduction and piezoelectric monitoring system for GIL pipelines laid along bridges. This system solves the problems of poor deformation adaptability, significant wind-induced sloshing, narrow vibration isolation bandwidth, insufficient self-vibration suppression, and complex condition monitoring in existing GIL support systems laid along bridges. It achieves four-level synergistic vibration reduction and isolation through "hinged energy release - tuned anti-sloshing - elastic vibration isolation - damping vibration suppression", and utilizes the liquid sloshing in the anti-sloshing water tank to drive the piezoelectric unit to achieve self-driven vibration state monitoring.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An integrated liquid anti-sway vibration isolation and piezoelectric monitoring system for GIL pipelines laid along bridges includes a bridge body, a suspension platform, a vibration damping platform, pipeline supports, and GIL pipelines. The suspension platform is suspended from the bottom of the bridge via a hanger with a universal joint, serving as the load-bearing foundation for the anti-sway water tank and the vibration damping platform. The anti-sway water tank is fixedly mounted on the suspension platform and filled with working fluid tuned to a target frequency, suppressing the lateral sway of the suspension platform through liquid sloshing. The vibration damping platform is positioned between the suspension platform and the pipeline supports, isolating vibrations transmitted from the bridge through the synergistic action of elastic elements and dampers. The GIL pipeline is fixed above the vibration damping platform via pipeline supports with damping layers, and the damping layer inside the pipe clamp absorbs the pipeline's own vibration. A dual-piezoelectric cantilever beam monitoring unit is installed inside the anti-sway water tank, using liquid sloshing to drive the cantilever beam vibration and generate piezoelectric signals, achieving self-driven monitoring of the system's vibration state.

[0007] Furthermore, both ends of the boom are connected to the bridge and the suspension platform respectively using universal joints. The universal joints adopt a cross-axis double rotating pair structure, which has rotational degrees of freedom in both the lateral and longitudinal directions. This can effectively release the bending and torsional constraints caused by bridge deformation, avoid additional stress concentration caused by rigid connection, and reduce the transmission efficiency of vibration at the connection node.

[0008] Furthermore, the suspension rod adopts an adjustable length structure, which allows for continuous adjustment of the installation height of the suspension platform by changing the installation position of the connecting rod on the connecting plate, thus adapting to different clearance requirements and installation errors at the bottom of bridges.

[0009] Furthermore, the anti-sway water tank is essentially a tuned liquid damper (TLD). The first-order sway frequency of its working liquid is tuned based on the wind environment parameters of the bridge site, the inherent characteristics of the suspension system, and the mass of the GIL pipeline, so that the sway frequency of the liquid is close to the target vibration reduction frequency of the suspension platform. The inertial force generated by the resonant sway of the liquid is used to counteract the vibration energy of the platform. The anti-sway water tank is equipped with a water inlet and a water level sensor to monitor the liquid level in real time and prompt for liquid replenishment when the liquid level is insufficient, so as to ensure stable tuned vibration reduction performance.

[0010] Furthermore, the dual piezoelectric cantilever beam monitoring unit inside the anti-sloshing water tank adopts a symmetrical differential structure, with the two piezoelectric plates connected with opposite polarities. When the liquid sloshes and impacts the free end of the cantilever beam, strains in opposite directions are generated on both sides of the fixed end of the cantilever beam, causing the two piezoelectric plates to output charge signals with opposite polarities. After differential processing, common-mode interference can be effectively suppressed, and the monitoring sensitivity can be improved. This monitoring unit does not require an additional power supply and directly uses the mechanical energy of the liquid sloshing to generate an electrical signal, realizing self-driven state monitoring.

[0011] Furthermore, the vibration reduction platform adopts a parallel "spring-damper" structure, with the damper located at the center of the platform and multiple helical springs evenly distributed around the damper. The springs have a detachable installation structure, allowing for the replacement of springs with different stiffnesses according to the vibration characteristics of different bridge sites, thereby adjusting the system's vibration isolation frequency. When vibration is transmitted to the vibration reduction platform, the vibration energy is first stored and absorbed through the elastic deformation of the springs, and then converted into heat energy dissipation through the viscous dissipation of the damper, achieving effective isolation of medium and high frequency vibrations.

[0012] Furthermore, the pipe support adopts a split pipe clamp structure, with a composite damping material layer pasted on the inner side of the pipe clamp. After the pipe clamp clamps the GIL pipe, the damping layer is tightly attached to the outer surface of the pipe. When the GIL pipe generates its own operating vibration, the damping layer absorbs the high-frequency micro-vibration energy through shear deformation and internal friction, preventing the vibration from being reflected and amplified between the pipe and the support.

[0013] Compared with the prior art, the present invention has the following advantages: First, this invention pioneers a four-level collaborative vibration reduction and isolation system, forming a multi-level vibration transmission path of "universal hinge energy release - anti-sway water tank tuning anti-sway - spring damping vibration isolation - pipe clamp damping layer vibration suppression". It performs division of labor control for vibrations of different frequencies and directions: the universal hinge mainly releases low-frequency large displacement deformation, the anti-sway water tank mainly controls wind-induced vibration in the transverse direction of the bridge, the spring damping platform mainly isolates medium and high frequency bridge vibration, and the pipe clamp damping layer mainly suppresses the high-frequency micro-vibration of the GIL itself. It realizes wide-band and multi-directional vibration control. Compared with traditional rigid suspension supports, the vibration acceleration level of the GIL pipeline can be reduced by more than 20dB, and the amplitude of wind-induced lateral sway can be reduced by more than 60%. The vibration reduction effect is significantly better than that of a single-level vibration reduction structure. Secondly, this invention achieves the integrated integration of vibration reduction and condition monitoring. It is the first to integrate a dual piezoelectric cantilever beam monitoring unit inside a tuned liquid damper. It uses the liquid sloshing that inevitably occurs when the anti-sloshing water tank is working to drive the cantilever beam to vibrate and generate an electrical signal. It does not require additional sensor installation or additional power supply wiring. It directly uses the liquid kinetic energy in the vibration reduction process to achieve self-driven monitoring of the vibration state. This reduces the cost and complexity of the monitoring system and achieves the reuse of vibration reduction and monitoring functions, resulting in a high degree of system integration. Third, the present invention adopts an omnidirectional articulated suspension structure. The cross-axis universal articulated joint has rotational freedom in two directions, which can adapt to the spatial angular deformation and large displacement of the bridge under the action of temperature, vehicles and wind loads. It can adapt to the maximum longitudinal displacement of ±300mm, lateral displacement of ±150mm and angular deformation of ±2° of the bridge, effectively avoiding the problem of additional stress on the pipeline caused by rigid connection and improving the system's adaptability to large deformation of the bridge. Fourth, the present invention has good parameter adjustability. The length of the hanger can be adjusted to adapt to different installation clearances. The elastic element can be replaced to adapt to bridges with different vibration characteristics. The level of the anti-sway water tank can be adjusted to achieve frequency tuning. The pipe clamp damping layer can be replaced with damping components of different thicknesses and materials according to the pipe vibration characteristics. It can optimize parameters according to the specific conditions of different bridge sites and has strong engineering adaptability. Fifth, the invention has a simple and reliable structure, and all components are made of mature industrial products. It is easy to manufacture and install, and the cost is low. It is suitable for both the laying of GIL in newly built long-span bridges and the retrofitting of GIL in existing bridges, and has good engineering promotion and application value. Attached Figure Description

[0014] Figure 1 This is a front view of the overall structure of an embodiment of the present invention; Figure 2 This is a side view of the overall structure of an embodiment of the present invention; Figure 3 This is an isometric side view of the overall structure of an embodiment of the present invention; Figure 4 This is an exploded view of the overall structure of an embodiment of the present invention; Figure 5 These are the front view and exploded view of the universal joint structure according to an embodiment of the present invention; wherein, Figure 5 a is a structural diagram of a universal joint. Figure 5 b is an exploded view of a universal joint; Figure 6 This is a schematic diagram of the four-stage vibration reduction and isolation principle of an embodiment of the present invention; wherein, Figure 6 a is a state diagram under minute perturbations in an embodiment of the present invention. Figure 6 b is a vibration reduction and isolation state diagram under large external forces such as lateral wind load or bridge vehicle load in an embodiment of the present invention; Figure 7 This is a schematic diagram of the working principle of the double piezoelectric cantilever beam inside the anti-sway water tank according to an embodiment of the present invention; Figure 8 This is a detailed diagram of the dual piezoelectric cantilever beam structure according to an embodiment of the present invention; Figure 9 This is a block diagram of the signal processing circuit of the monitoring unit in an embodiment of the present invention.

[0015] In the diagram: 1-Bridge main body; 2-GIL pipe; 3-Suspension platform; 31-First connecting rod; 32-First connecting plate; 33-Second connecting rod; 34-Bearing plate; 35-Anti-sway water tank; 36-Water inlet; 37-Cantilever beam; 38-First piezoelectric element; 39-Second piezoelectric element; 40-Water level sensor; 4-Vibration damping platform; 41-Damper; 42-Elastic element; 43-Second connecting plate; 5-Pipe support; 51-Damping buffer material; 52-Upper pipe clamp; 53-Pipe clamp support; 54-Lower pipe clamp; 6-Universal hinge joint; 61-Upper hinge seat; 62-Lower hinge seat; 63-Cross shaft; 7-Signal output module. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0017] like Figures 1-4 As shown in this embodiment, an integrated system for liquid anti-sloshing, vibration reduction and piezoelectric monitoring for laying GIL pipelines along bridges is disclosed. It is mainly applied to the laying of GIL pipelines along bridges for cable-stayed bridges with a main span of 500m. The system is set up every 12m-18m along the longitudinal direction of the bridge. Each system can carry a GIL pipeline section with a length of 15m and an outer diameter of 500mm.

[0018] The system includes a bridge body 1, a suspension platform 3, a vibration damping platform 4, pipe supports 5, and a GIL pipe 2. The suspension platform 3 is suspended from the bottom box girder of the bridge body 1 by two pairs of symmetrically arranged hangers. The upper and lower ends of each hanger are connected to the pre-embedded connecting ear plate at the bottom of the bridge and the bearing plate 34 of the suspension platform 3 by universal joints 6, respectively.

[0019] like Figure 5 As shown, the universal joint 6 includes an upper hinge seat 61, a lower hinge seat 62, and a cross shaft 63. The upper hinge seat 61 is fixed to the pre-embedded ear plate at the bottom of the bridge by bolts, and the lower hinge seat 62 is connected to the end of the hanger rod by threads. The cross shaft 63 is located between the upper hinge seat 61 and the lower hinge seat 62, and is hinged to the upper hinge seat 61 and the lower hinge seat 62 by two mutually orthogonal cylindrical pins, forming two independent rotating pairs in the transverse and longitudinal directions, with a rotation angle range of not less than ±15° in each direction. The pins are made of 40Cr alloy structural steel with surface hardening treatment. The mating parts of the pins and the ear holes of the hinge seats are inlaid with tin bronze wear-resistant bushings to reduce rotational friction resistance. Flat washers and cotter pins are installed at both ends of the pins for axial limiting to prevent the pins from coming out under vibration conditions. This universal hinge structure allows the hanger to rotate freely with the deformation of the bridge, effectively releasing the bending and torsional constraints of the connection node, avoiding additional stress in the GIL pipe caused by bridge deformation, and reducing the transmission efficiency of structural vibration at the connection node.

[0020] The suspension rod includes a first connecting rod 31, a second connecting rod 33, and a first connecting plate 32. The upper end of the first connecting rod 31 is connected to the lower hinge seat 62, and the lower end passes through the positioning hole on the first connecting plate 32 and is locked with double nuts. The lower end of the second connecting rod 33 is connected to the bearing plate 34 of the suspension platform 3, and the upper end passes through the corresponding positioning hole on the first connecting plate 32 and is locked with double nuts. The first connecting plate 32 has three positioning holes arranged vertically at 50mm intervals. By installing the first connecting rod 31 in different positioning holes, the installation height of the suspension platform 3 can be continuously adjusted within a range of ±100mm to adapt to changes in clearance and installation errors at different positions under the bridge.

[0021] The suspended platform 3 consists of a bearing plate 34 welded from steel profiles and an anti-sway water tank 35 fixedly installed on the bearing plate 34. The bearing plate 34 is made of Q355B steel plate welded into a box-shaped structure, with pre-drilled threaded holes for the vibration damping platform on its upper surface. The anti-sway water tank 35 is made of stainless steel plate welded into a rectangular structure, with a length L of 800mm, a width of 600mm, and a height of 500mm along the transverse direction of the bridge, and is fixedly installed in the middle of the bearing plate 34. The top of the anti-sway water tank 35 is equipped with a water inlet 36 with a sealed cover for injecting working fluid (in this embodiment, an aqueous solution with added antifreeze is used, suitable for ambient temperatures from -20℃ to +60℃). An immersion-type water level sensor 40 is installed inside the top of the anti-sway water tank 35 to monitor the liquid level in real time. The signal output line of the water level sensor 40 is laid along the suspension rod to a monitoring terminal in the bridge maintenance passage. When the liquid level is more than 5% lower than the design level, the monitoring terminal issues an audible and visual alarm signal to prompt maintenance personnel to replenish the liquid.

[0022] In this embodiment, the total mass of the suspended platform 3 and the upper GIL pipeline is approximately 1200 kg, and the natural frequency of the suspension system in the transverse direction is approximately 0.8 Hz. Based on the design principle of the tuned liquid damper, the first-order sloshing frequency of the working liquid in the anti-sloshing tank 35 is calculated using the following formula: ; In the formula: f is the first-order sloshing frequency of the liquid, in Hz; g is the gravitational acceleration, taken as 9.81 m / s²; L is the length of the anti-sloshing water tank along the transverse direction of the bridge, which is 0.8 m in this embodiment; h is the liquid level height of the working liquid, in m.

[0023] To achieve optimal tuning and vibration reduction, the liquid level height h is adjusted so that the first-order sway frequency f of the liquid is close to the natural frequency of the suspension system (0.8Hz). Calculations show that when the liquid level height h is 220mm, the first-order sway frequency is approximately 0.79Hz, with a deviation from the target frequency of less than 2%, meeting the tuning requirements. At this point, the liquid mass in the anti-sway tank is approximately 105kg, with a mass ratio of approximately 8.7%, providing good tuning and vibration reduction. When the transverse wind load or seismic action causes lateral vibration of the suspension platform, the liquid in the anti-sway tank 35 resonates and sways. The inertial force generated by the liquid movement is opposite to the direction of platform vibration. Through the collision between the liquid and the tank wall, and the dissipation of vibration energy through viscous friction within the liquid, the amplitude of the transverse wind-induced sway of the suspension platform can be reduced by more than 60%.

[0024] like Figure 7 and Figure 8 As shown, the anti-sloshing water tank 35 is equipped with a liquid sloshing monitoring unit. This monitoring unit includes a cantilever beam 37, a first piezoelectric element 38, a second piezoelectric element 39, and a signal output module 7. The cantilever beam 37 is made of 65Mn spring steel sheet, with a length of 120mm, a width of 20mm, and a thickness of 0.8mm. Its upper end is fixed to a bracket at the top inside the anti-sloshing water tank 35 by bolts, while its lower end freely extends into the working liquid, with an immersion depth of approximately 80mm. The first piezoelectric element 38 and the second piezoelectric element 39 are PZT-5H piezoelectric ceramic sheets, with dimensions of 20mm × 15mm × 0.2mm. They are symmetrically attached to the left and right surfaces near the fixed end of the cantilever beam 37, respectively. The two piezoelectric elements have opposite polarization directions and are connected using a differential method with opposite polarities.

[0025] When the liquid in the anti-sloshing water tank 35 sloshes, the liquid flow impacts the free end of the cantilever beam 37, causing the cantilever beam 37 to bend and vibrate. Equal but opposite strains are generated on both sides of the fixed end of the cantilever beam 37, causing the first piezoelectric element 38 and the second piezoelectric element 39 to output piezoelectric charge signals of opposite polarities. The two piezoelectric signals are led out of the water tank through waterproof wires and connected to the signal output module 7. For example... Figure 9As shown, the signal output module 7 includes a charge amplifier, a differential rectifier module, a signal conditioning circuit, a low-pass filter, and an AD converter connected in sequence. The charge amplifier first converts the high-impedance charge signal output by the piezoelectric element into a low-impedance voltage signal and performs primary amplification. The differential rectifier module performs differential processing on the two inverted voltage signals, effectively canceling common-mode noise such as temperature drift and electromagnetic interference, and doubling the effective signal amplitude. The signal conditioning circuit adjusts the signal amplitude and performs impedance matching. The low-pass filter filters out high-frequency noise above 100Hz. Finally, the AD converter converts the signal into a digital signal, which is transmitted to the monitoring terminal via a bus. This monitoring unit does not require an external power supply and directly uses the mechanical energy of liquid sloshing to generate an electrical signal. The output voltage amplitude is linearly related to the vibration acceleration, and the monitoring sensitivity can reach 50mV / g. It can accurately monitor vibration acceleration above 0.01g, realizing real-time monitoring of the swaying of suspended platforms, bridge vibration, and GIL pipeline vibration.

[0026] The vibration damping platform 4 is installed above the load-bearing plate 34 of the suspension platform 3, and includes two parallel second connecting plates 43, as well as a damper 41 and an elastic element 42 disposed between the two connecting plates. The damper 41 is a viscous fluid damper with a rated damping force of 5kN and a damping coefficient of 20kN·s / m. It is vertically installed at the center of the two connecting plates, and its two ends are bolted to the upper and lower connecting plates via flanges. The elastic element 42 is a cylindrical helical compression spring, with a total of 6 springs evenly distributed along the circumference of the damper 41. The spring stiffness is 200N / mm, and the upper and lower ends of the springs are connected to the upper and lower connecting plates via positioning seats, using a bolted detachable installation method. When it is necessary to adapt to bridges with different vibration characteristics, springs with different stiffnesses can be replaced to adjust the system's natural frequency and achieve the best vibration isolation effect. In this embodiment, the natural frequency of the vibration damping platform is designed to be 3Hz, which can effectively isolate medium and high frequency bridge vibrations above 5Hz, and the vibration transmissibility can be reduced to below 0.2. When vibration is transmitted to the vibration damping platform, the spring first undergoes elastic deformation to store the vibration energy. Then, the damper converts the vibration energy into heat energy and dissipates it through fluid viscosity, thus achieving secondary isolation of vibration.

[0027] The pipe support 5 is installed above the upper connecting plate of the vibration damping platform 4 and includes a pipe clamp support 53, an upper pipe clamp 52, and a lower pipe clamp 54. The pipe clamp support 53 is welded from Q355B steel plate, and its lower part is fixed to the upper connecting plate of the vibration damping platform by bolts, while its upper part is welded to the lower pipe clamp 54 as a whole. The upper pipe clamp 52 and the lower pipe clamp 54 are made of cast steel, and their inner sides are arc surfaces that match the outer diameter of the GIL pipe 2. Damping buffer material 51 is fixed on the arc surface by a vulcanization process. In this embodiment, the damping buffer material 51 is a composite damping material of butyl rubber and polyurethane, with a thickness of 10mm and a loss factor greater than 0.7. The upper pipe clamp 52 and the lower pipe clamp 54 are connected by high-strength bolts on both sides, clamping the GIL pipe 2 so that the damping buffer material 51 is in close contact with the outer surface of the GIL pipe 2, with a compression rate of approximately 20%. When the GIL pipeline 2 generates electromagnetic or mechanical vibration during operation, the damping buffer material 51 absorbs the high-frequency micro-vibration energy through shear deformation and internal friction, preventing the vibration from being reflected between the pipeline and the support, and can reduce the high-frequency vibration amplitude of the pipeline itself by more than 80%.

[0028] The suspension platform 3 and the vibration damping platform 4, as well as the vibration damping platform 4 and the pipe support 5, are all connected by 8.8 grade high-strength bolts. Disc-shaped anti-loosening washers are installed at the bolt connections to prevent the bolts from loosening under long-term vibration conditions and to ensure the reliability of the connection.

[0029] The working process of this embodiment is as follows: When the bridge undergoes slow displacement and angular deformation under temperature load, the universal joint 6 rotates freely, releasing deformation stress and avoiding additional stress in the GIL pipe, thus maintaining the system's static stability.

[0030] When the bridge experiences small-amplitude, medium-to-high-frequency vibrations due to vehicle loads, the vibrations are first transmitted to the suspension platform 3 via the universal joint 6. The rotational freedom of the joint isolates part of the vibration. The residual vibrations are transmitted to the damping platform 4, where they are significantly attenuated by the deformation of the elastic element 42 and the energy dissipation effect of the damper 41. Finally, the damping buffer material 51 of the pipe support 5 absorbs the residual high-frequency vibrations, ensuring that the vibration level of the GIL pipe 2 remains within the allowable range. At this time, the liquid in the anti-sway tank 35 only experiences small-amplitude swaying, and the cantilever beam monitoring unit outputs a small-amplitude vibration signal. The monitoring system records the vibration baseline under normal operating conditions.

[0031] When the bridge experiences significant lateral vibration due to strong winds or earthquakes, the liquid in the anti-sway tank 35 resonates and sloshes, dissipating most of the lateral vibration energy through liquid inertia and viscous friction, thus suppressing the lateral sway of the suspended platform. The residual vibration, after passing through two stages of damping—the damping platform 4 and the pipe support 5—is significantly attenuated by the time it reaches the GIL pipe 2. At this point, the liquid sloshing drives the cantilever beam 37 to vibrate at a large amplitude, causing the piezoelectric element to output a large-amplitude electrical signal. The monitoring system detects the strong vibration event, records the vibration time history data, and issues an early warning.

[0032] When the GIL pipe 2 itself generates operating vibration, the vibration is directly transmitted to the damping buffer material 51 inside the pipe clamp. The vibration energy is dissipated through the internal friction of the damping material, thus preventing the vibration from being transmitted to the support structure.

[0033] During system operation, the water level sensor 40 continuously monitors the liquid level in the anti-sloshing water tank 35. When the liquid level drops by more than 5% due to liquid evaporation or leakage, the monitoring system issues a liquid replenishment prompt. Maintenance personnel can replenish the liquid through the water inlet 36 to ensure that the anti-sloshing water tank is always in the best tuning state.

[0034] This embodiment verifies through finite element simulation and shaking table test: Under the action of level 8 wind load, the lateral sway amplitude of the suspended platform is only 12mm, which is much smaller than the 35mm of the traditional rigid support; Under the action of a level 7 earthquake, the maximum vibration acceleration of the GIL pipeline is 0.3g, which is much smaller than the 1.2g of the traditional support; The monitoring unit can accurately identify vibration accelerations above 0.02g, and the signal-to-noise ratio is greater than 30dB, which fully meets the requirements of engineering condition monitoring.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An integrated system for liquid anti-sloshing, vibration isolation, and piezoelectric monitoring of GIL pipelines laid along bridges, characterized in that, It includes the main bridge structure (1), the suspension platform (3), the vibration reduction platform (4), the pipe support (5), and the GIL pipe (2); The suspension platform (3) is suspended and connected to the bridge body (1) by at least one pair of hangers. Both ends of the hangers are connected to the bridge body (1) and the suspension platform (3) respectively by universal joints (6), forming a first-level hinged vibration isolation path to release the multi-directional rotational freedom generated by bridge deformation. An anti-sway water tank (35) is fixedly installed on the suspended platform (3). The anti-sway water tank (35) is filled with working fluid, and the first-order swaying frequency of the working fluid matches the target vibration frequency of the suspended platform (3). The liquid swaying generates an inertial force opposite to the direction of platform movement, forming a second-level tuned vibration reduction path to suppress the lateral swaying of the suspended platform caused by wind, earthquake or bridge vibration. The anti-sloshing water tank (35) is equipped with a liquid sloshing monitoring unit. The liquid sloshing monitoring unit includes a cantilever beam (37) with one end fixed to the top support structure inside the anti-sloshing water tank (35) and the free end extending into the working liquid area. A first piezoelectric sheet (38) and a second piezoelectric sheet (39) are symmetrically pasted on opposite sides of the fixed end of the cantilever beam (37), and a signal output module (7) connected to the two piezoelectric sheets. When the liquid sloshing drives the cantilever beam (37) to bend and vibrate, the two piezoelectric sheets output an electrical signal corresponding to the vibration intensity, thereby realizing the self-driven monitoring of the system vibration state. The vibration reduction platform (4) is set between the suspension platform (3) and the pipe support (5). The vibration reduction platform (4) includes a damper (41) and multiple elastic elements (42) located between the upper and lower connecting plates, forming a third-level elastic damping vibration isolation path. The transmission of bridge vibration to GIL pipe (2) is weakened by the energy absorption of elastic element deformation and energy dissipation of damper. The pipe support (5) includes a pipe clamp support (53), an upper pipe clamp (52) and a lower pipe clamp (54). A damping buffer material (51) is provided between the upper pipe clamp (52) and the lower pipe clamp (54) to form a fourth-level damping vibration suppression path, which is used to fix the installation of the GIL pipe (2) and absorb the vibration energy generated by the operation of the GIL pipe itself. The system forms a four-level synergistic vibration reduction and isolation path: universal hinge vibration isolation, anti-sway water tank tuning vibration reduction, elastic damping platform vibration isolation, and pipe clamp damping layer vibration suppression. The vibration energy is attenuated step by step during transmission, and vibration reduction and isolation and vibration status monitoring are integrated.

2. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The first piezoelectric element (38) and the second piezoelectric element (39) are connected with opposite polarities to form a differential output structure; the signal output module (7) includes a charge amplifier, a differential rectification module, a signal conditioning circuit, a low-pass filter and an AD converter connected in sequence to perform differential processing on the two piezoelectric signals to suppress common-mode interference, improve output sensitivity and realize high-precision acquisition of liquid sloshing monitoring signals.

3. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The first-order sloshing frequency of the working fluid in the anti-sloshing water tank (35) is calculated according to the following formula: ； In the formula: f is the first-order sloshing frequency of the liquid, in Hz; g is the acceleration due to gravity, taken as 9.81 m / s²; L is the length of the anti-sloshing water tank along the vibration direction, in m; h is the liquid level height of the working liquid, in m; Before system installation, the target vibration frequency is determined based on the wind speed parameters at the bridge site, the total mass of the suspended platform, the stiffness of the boom connection, and the dynamic characteristics of the GIL pipeline. By adjusting the liquid level height h, the deviation between the first-order sloshing frequency f of the liquid and the target vibration frequency is kept within ±5%, thus achieving tuned vibration reduction.

4. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The suspension rod includes a first connecting rod (31), a second connecting rod (33), and a first connecting plate (32). The first connecting plate (32) has multiple bolt positioning holes spaced apart in the horizontal direction. The first connecting rod (31) passes through different positioning holes and is fastened to the first connecting plate (32) by bolts and nuts. By adjusting the connection position between the first connecting rod (31) and the first connecting plate (32), the installation height of the suspension platform (3) relative to the bridge body (1) can be adjusted. The adjustment range is not less than ±100mm to adapt to the installation requirements of different bridge structures.

5. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The universal joint (6) includes an upper hinge seat (61), a lower hinge seat (62), and a cross shaft (63). The cross shaft (63) is hinged to the upper hinge seat (61) and the lower hinge seat (62) respectively by two mutually orthogonal pins, forming a double-axis rotation pair, so that the boom has a rotational freedom of not less than ±15° in both the lateral and longitudinal directions. The mating part between the pin and the hinge seat is provided with a wear-resistant copper alloy bushing, and the two ends of the pin are equipped with washers and cotter pins for axial limiting.

6. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The anti-sloshing water tank (35) is equipped with a water inlet (36) on the top and a water level sensor (40) inside. The water level sensor (40) is electrically connected to an external alarm device to monitor the liquid level of the working liquid in real time. When the liquid level is more than 5% lower than the design value, a liquid replenishment prompt signal is issued to ensure that the anti-sloshing water tank (35) always maintains the design liquid level.

7. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The elastic element (42) is a cylindrical helical spring, with 4-8 springs evenly distributed around the damper (41). The elastic element (42) adopts a bolt-detachable connection structure, and springs with different stiffness specifications can be replaced according to the actual vibration conditions of the bridge to adjust the natural frequency of the system and adapt to vibration excitation of different intensities.

8. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The damping buffer material (51) is a damping material composed of butyl rubber and polyurethane, with a thickness of 5-15mm. It is fixed to the inner arc surface of the upper pipe clamp (52) and the lower pipe clamp (54) by vulcanization process, and is closely attached to the outer surface of the GIL pipe (2). It absorbs the high-frequency vibration energy of the GIL pipe during operation through the shear deformation and internal friction of the material.

9. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The bearing plate (34) of the suspension platform (3) is connected to the lower connecting plate of the vibration damping platform (4), and the upper connecting plate of the vibration damping platform (4) is connected to the mounting base plate of the pipe support (5) by high-strength bolts of grade 8.8 or above. Anti-loosening washers are provided at the bolt connection to prevent the connection from loosening under vibration conditions.

10. The integrated system for liquid anti-sloshing, vibration reduction, and piezoelectric monitoring of GIL pipelines laid along bridges according to claim 1, characterized in that, The system is suitable for laying GIL pipelines in long-span cable-stayed bridges or suspension bridges with a main span of more than 200m. It can adapt to the maximum longitudinal displacement of ±300mm, lateral displacement of ±150mm and angular deformation of ±2° of the bridge. Compared with traditional rigid suspension supports, the vibration acceleration level of GIL pipelines is reduced by more than 20dB and the wind-induced lateral sway amplitude is reduced by more than 60%.

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