Intelligent main cable air bag device for restraining flutter of suspension bridge

Abstract

The invention discloses an intelligent main cable air bag device for restraining flutter of a suspension bridge, and relates to the technical field of bridge engineering, an air bag structure is installed on a main cable to restrain flutter of the bridge, and main cable air bag control parameters needed for restraining the flutter of the bridge are determined according to the wind speed and the wind direction near the bridge. The diameters of the main cable air bags at different positions can be changed to the corresponding diameters, the resistance borne by the main cable is improved, the negative work of the resistance of the main cable on the whole structure of the bridge is increased, then energy dissipation of a bridge vibration system can be remarkably increased, and therefore the flutter displacement response of the bridge is restrained. When the wind speed at the bridge site does not reach the flutter critical wind speed, the air bag system is in a contraction state, and vortex vibration of the main cable can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of bridge engineering, and more particularly to an intelligent main cable airbag device for suppressing the flutter of a suspension bridge. Background Art

[0002] At present, with the rapid development of social economy and science and technology, the span records of modern bridge structures are constantly being refreshed, and the structural form is developing in a softer and more slender direction. In addition, in order to meet higher standards of navigation requirements, the demand for super-long span bridges is becoming increasingly strong. The continuous increase in bridge spans directly leads to increasing wind sensitivity, and wind resistance has become the main control factor in the design of large-span bridges. Among them, flutter control is the top priority of wind-resistant design of large bridges. Flutter is a divergent self-excited vibration and an aerodynamic instability phenomenon. It is caused by aerodynamic negative damping generated by torsional vibration or bending-torsion coupled vibration. It is the most destructive wind-induced vibration and is not allowed to occur on real bridges. It must be avoided through wind-resistant optimization design.

[0003] At present, bridge flutter control can usually be started from three aspects, namely, improving the stiffness and damping of the bridge structure and improving the cross-sectional shape of the bridge. From the perspective of control form, it can be divided into mechanical control measures and flow control measures. Traditional flutter control methods applied to bridges are mostly pneumatic measures, that is, streamlining the cross-sectional shape of the bridge as much as possible, or installing corresponding spoilers, but these measures are usually not universal, and wind tunnel tests are required for different main beam sections to verify their reliability. And it can be foreseen that as the bridge structure continues to become lighter and longer, traditional pneumatic control measures may be difficult to meet the requirements of structural flutter suppression. In order to break through the bottleneck, it is very necessary to develop more efficient and more universal bridge flutter suppression measures.

[0004] For example, sealing grids and central stabilizing plates can be used to change the aerodynamic shape of the truss main beam to suppress flutter. However, the parameters of this structure are only applicable to this truss main beam section. Its applicability to different truss main beam sections still needs to be verified through wind tunnel tests, and it is not very universal.

[0005] Therefore, how to provide a universal flutter suppression measure for suspension bridges is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0006] In view of this, the present invention provides an intelligent main cable airbag device for suppressing the flutter of a suspension bridge to solve the problems existing in the background technology.

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

[0008] An intelligent main cable airbag device for suppressing the flutter of a suspension bridge comprises: a control system and an airbag system;

[0009] The control system includes a monitoring device and a control center; the monitoring device monitors the real-time wind speed and wind direction at the bridge site through a wind speed and wind direction sensor, and monitors the real-time inflation state of the main cable airbag through an inflation sensor; the control center is connected to the monitoring device, determines the shape parameters of the main cable airbag according to the monitored wind field characteristics of the bridge site, and determines the inflation state of the airbag system according to the monitored real-time state of the airbag;

[0010] The airbag system is wrapped around the main cable; the airbag system is connected to the control center, and the control parameters of the main cable airbags at different positions are determined according to the real-time wind field characteristics at the bridge site, and the sizes of the main cable airbags at different positions are changed.

[0011] Optionally, the airbag system includes a main cable airbag, an inflation device and an inflation duct; the main cable airbag is connected to the inflation device via the inflation duct, and the inflation device inflates the main cable airbag to make the main cable airbag reach a preset diameter.

[0012] Optionally, the main cable airbag is wrapped around the main cable and has a cylindrical appearance; the control parameters of the main cable airbag include the position along the bridge span direction and the outer diameter of the airbag.

[0013] Optionally, when the wind speed at the bridge site reaches near the critical wind speed for flutter, the main cable airbag control parameters required to suppress bridge flutter are determined according to the wind speed and wind direction near the bridge, and the main cable airbags at different positions are transformed to corresponding diameters, thereby increasing the critical wind speed for flutter of the bridge.

[0014] Optionally, wind speed and direction sensors are arranged at intervals along the span direction of the bridge to monitor the wind field distribution characteristics near the entire bridge; and inflation sensors are arranged along the span direction of the bridge to monitor the inflation status of the main cable airbags of the entire bridge.

[0015] Optionally, the airbag system includes a plurality of main cable airbags; the main cable airbags are usually arranged along the span direction of the bridge, and according to the distribution characteristics of the wind field, the control parameters of the main cable airbags at different positions are different.

[0016] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses an intelligent main cable airbag device for suppressing the flutter of a suspension bridge. When the wind speed at the bridge site exceeds the critical wind speed of flutter, the bridge will flutter. The main cable will provide resistance in the opposite direction of the movement of the main beam, and will always do negative work on the bridge vibration system, which will dissipate the energy of the bridge vibration system. Therefore, the bridge flutter is suppressed by installing an airbag structure on the main cable, and the main cable airbag control parameters required to suppress the bridge flutter are determined according to the wind speed and wind direction near the bridge. The main cable airbags at different positions can be transformed to the corresponding diameter, which increases the resistance of the main cable and increases the negative work done by the main cable resistance on the overall structure of the bridge, thereby significantly increasing the energy dissipation of the bridge vibration system, thereby suppressing the bridge flutter displacement response. When the wind speed at the bridge site does not reach the critical wind speed of flutter, the airbag system is in a contracted state to avoid the occurrence of vortex vibration of the main cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 The accompanying drawing is a three-dimensional schematic diagram of the intelligent main cable airbag device for a suspension bridge provided by the present invention;

[0019] Figure 2 The accompanying drawing is a cross-sectional schematic diagram of the working state of the intelligent main cable airbag device of the suspension bridge provided by the present invention;

[0020] Figure 3 The accompanying drawing is a cross-sectional schematic diagram of the suspension bridge intelligent main cable airbag device provided by the present invention in a non-working state;

[0021] Figure 4 The accompanying figure is a schematic diagram of the segment model elastic suspension system with main cable provided by the present invention

[0022] Figure 5 The accompanying drawing is a curve showing the change of the steady-state amplitude of the torsion direction with the wind speed provided by the present invention;

[0023] Figure 6 The accompanying drawing is a curve showing the change of the vertical steady-state amplitude with wind speed provided by the present invention;

[0024] Among them, 1-bridge; 101-main beam; 102-top plate; 103-bottom plate; 104-suspender rod; 105-main cable; 106-cable clamp; 2-airbag system; 201-main cable airbag; 202-inflating device; 203-inflating duct; 3-control system; 301-control center; 302-data transmission line. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The embodiment of the present invention discloses an intelligent main cable airbag device for suppressing the flutter of a suspension bridge, such as Figure 1 As shown, it includes: a control system 3 and an airbag system 2;

[0027] The control system 3 includes a monitoring device and a control center 301; the monitoring device monitors the real-time wind speed and wind direction at the bridge site through a wind speed and wind direction sensor, and monitors the real-time inflation state of the main cable airbag through an inflation sensor; the control center 301 is connected to the monitoring device, determines the shape parameters of the main cable airbag according to the monitored wind field characteristics of the bridge site, and determines the inflation state of the airbag system 2 according to the monitored real-time state of the airbag;

[0028] The airbag system 2 is wrapped around the main cable 105; the airbag system 2 is connected to the control center 301, and the control parameters of the main cable airbags 201 at different positions are determined according to the real-time wind field characteristics at the bridge site, and the sizes of the main cable airbags 201 at different positions are changed;

[0029] The airbag system 2 comprises a main cable airbag 201, an inflating device 202 and an inflating conduit 203; the main cable airbag 201 is connected to the inflating device 202 via the inflating conduit 203, and the inflating device 202 inflates the main cable airbag 201 to make the main cable airbag 201 reach a preset diameter.

[0030] In a specific embodiment, Figure 2 As shown, the airbag system 2 is arranged on both sides of the bridge 1; the inflation device 202 in the airbag system 2 is connected to the control center 301 through the data transmission line 302; the bridge 1 includes a main beam 101, a top plate 102, a bottom plate 103, a hanger 104, a main cable 105 and a cable clamp 106; the main cable airbag 201 is wrapped on the main cable 105 and has a cylindrical appearance; the control parameters of the main cable airbag 201 include the position along the bridge span direction and the outer diameter of the main cable airbag 201.

[0031] In a specific embodiment, when the wind speed at the bridge site reaches near the critical wind speed for flutter, the main cable airbag control parameters required to suppress bridge flutter are determined based on the wind speed and wind direction near the bridge, and the main cable airbags 201 at different positions are transformed to corresponding diameters, thereby increasing the critical wind speed for flutter of the bridge.

[0032] In a specific embodiment, it also includes arranging wind speed and direction sensors at intervals along the span direction of the bridge to monitor the wind field distribution characteristics near the entire bridge; and arranging inflation sensors along the span direction of the bridge to monitor the inflation status of the main cable airbags of the entire bridge.

[0033] In a specific embodiment, the airbag system 2 includes a plurality of main cable airbags 201; the main cable airbags 201 are usually arranged along the span direction of the bridge, and according to the distribution characteristics of the wind field, the control parameters of the main cable airbags at different positions are different.

[0034] In a specific embodiment, the airbag system 2 is arranged on both sides of the main beam 101 in a non-working state. Figure 3 As shown, it does not affect the operation of the bridge 1 nor the appearance of the bridge 1. The inflator 202 is fixedly connected to the bottom plate 103 of the bridge 1, and the airbag system 2 is connected to the main beam 101, which can be welded or chemically connected, connected by high-strength rivets or high-strength bolts, etc.

[0035] In a specific embodiment, in order to verify the influence of the main cable diameter on the flutter performance of the bridge, a segment model wind tunnel test was carried out. The steel truss segment model with the main cable is as follows: Figure 4 As shown, the scale ratio of the segment model is 1:60, the model is 1.58m long, and the shape of the model is simulated strictly according to the geometric scale ratio. In order to ensure the duality of the flow field near the main beam segment model, end plates are set at both ends of the model. In this case, a rigid main cable model is installed on the steel truss segment model by consolidation. The main cable diameter adopts two specifications for comparative tests, namely 16mm (original design scheme) and 32mm (thickened scheme), and the mass and dynamic parameters of the two scheme models are controlled to be consistent. The total mass of the segment model is 28.091kg, and the torsional moment of inertia is 1.251kg·m 2 / m, and the free vibration attenuation test measured the vertical bending and torsional frequencies to be 1.587Hz and 2.48Hz respectively, and the vertical bending and torsional damping to be 0.42% and 0.47% respectively.

[0036] Figure 5 and Figure 6 The nonlinear flutter response results of the segment model with 16mm and 32mm rigid main cables are given. It can be seen that when the mass, frequency and damping of the two models are basically the same, the critical flutter wind speed of the segment model with 32mm rigid main cable is about 6m / s higher than that of the segment model with 16mm rigid main cable, and the torsional and vertical displacement responses after flutter are also significantly reduced. Therefore, according to the wind tunnel test results of the segment model, the increase in the diameter of the main cable will significantly increase the critical flutter wind speed of the bridge and reduce the displacement response after flutter, which can effectively suppress the flutter of the bridge and improve the wind resistance safety performance of the bridge.

[0037] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0038] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An intelligent main cable airbag device for suppressing the flutter of a suspension bridge, characterized in that: include: Control systems and airbag systems; The control system includes a monitoring device and a control center; the monitoring device monitors the real-time wind speed and wind direction at the bridge site through a wind speed and wind direction sensor, and monitors the real-time inflation state of the main cable airbag through an inflation sensor; the control center is connected to the monitoring device, determines the shape parameters of the main cable airbag according to the monitored wind field characteristics of the bridge site, and determines the inflation state of the airbag system according to the monitored real-time state of the airbag; The airbag system is wrapped around the main cable; the airbag system is connected to the control center, and the control parameters of the main cable airbags at different positions are determined according to the real-time wind field characteristics at the bridge site, and the sizes of the main cable airbags at different positions are changed; The airbag system comprises a main cable airbag, an inflating device and an inflating conduit; the main cable airbag is connected to the inflating device through the inflating conduit, and the inflating device inflates the main cable airbag to make the main cable airbag reach a preset diameter.

2. The intelligent main cable airbag device for suppressing suspension bridge flutter according to claim 1 is characterized in that: The main cable airbag is wrapped on the main cable and has a cylindrical appearance. The control parameters of the main cable airbag include the position along the bridge span direction and the outer diameter of the airbag.

3. The intelligent main cable airbag device for suppressing suspension bridge flutter according to claim 2 is characterized in that: When the wind speed at the bridge site reaches near the critical wind speed for flutter, the main cable airbag control parameters required to suppress bridge flutter are determined according to the wind speed and wind direction near the bridge. The main cable airbags at different positions are transformed to corresponding diameters, thereby increasing the critical wind speed for flutter of the bridge.

4. The intelligent main cable airbag device for suppressing suspension bridge flutter according to claim 1, characterized in that: It also includes wind speed and direction sensors arranged at intervals along the span direction of the bridge to monitor the wind field distribution characteristics near the entire bridge; and inflation sensors arranged along the span direction of the bridge to monitor the inflation status of the main cable airbags of the entire bridge.

5. The intelligent main cable airbag device for suppressing suspension bridge flutter according to claim 1, characterized in that: The airbag system includes a plurality of main cable airbags; the main cable airbags are usually arranged along the span direction of the bridge, and the control parameters of the main cable airbags at different positions are different according to the distribution characteristics of the wind field.

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