CN108643019B

CN108643019B - Bridge flutter and vortex vibration integrated control device and control method thereof

Info

Publication number: CN108643019B
Application number: CN201810659868.0A
Authority: CN
Inventors: 赵林; 胡传新; 葛耀君
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2018-06-22
Filing date: 2018-06-22
Publication date: 2020-03-27
Anticipated expiration: 2038-06-22
Also published as: CN108643019A

Abstract

The invention discloses a bridge flutter and vortex vibration integrated control device and a control method thereof, wherein a bridge girder comprises two polygonal box girders which are symmetrical along a central line and are provided with outer side air nozzles, the control device comprises upper and lower cover plates which can be contracted and rotated and a power device which is positioned in the box girders, the upper and lower cover plates are arranged on the inner sides of opposite surfaces of the split type box girders, and the upper and lower cover plates can be contracted and rotated relative to the polygonal box girders. The technical problem of can not simultaneous control flutter and vortex shake that exists in the present split type bridge structures is solved, utilize scalable apron, can adjust according to the characteristic of incoming flow wind, the flutter stability and the vortex performance of large-span bridge have been guaranteed simultaneously in this kind of adjustment.

Description

Bridge flutter and vortex vibration integrated control device and control method thereof

Technical Field

The invention relates to the technical field of bridges, in particular to an integrated control device capable of improving the flutter and vortex vibration stability of a split box girder and a control method thereof.

Background

In 1940, the Tacoma bridges (Tacoma winds Bridge) in breeze (8 th wind, wind speed about 19m/s) experienced previously unseen torsional vibrations, i.e. periodic alternating undulations on both sides of the deck. Along with the looseness of the cable clamp at the joint of the main cable at one midspan side and the suspender, one side of a half-span road surface of the main span of the sudden bridge is lifted, so that the main span of the bridge is violently twisted, and the other half span is twisted subsequently. And then, the vibration amplitude is continuously increased, after the maximum torsion amplitude reaches about 35 degrees, the suspension ropes are broken one by one, and finally the bridge deck is collapsed. After the incident, many world famous scholars have conducted analytical studies on the cause of the incident and have gained wide consensus to attribute the collapse of the tacoma bridge to the negative damping driven split stream torsional flutter caused by wind. Since then, the flutter control study of large span bridges has become one of the most important concerns for all bridge designers.

Bridge flutter is destructive self-excited divergent vibration, which is represented by interaction between a flow field and a structure, and causes the torsional amplitude to be increased continuously until wind damage. Mainly because the vibrating structure is able to continuously absorb energy in the flowing air, which is in turn greater than the energy dissipated by the structure damping in the vibrations. When the airflow passes through the streamline section, the flowing speed of the airflow mainly influences or changes the amplitude and phase relation between the twisting freedom degrees and the bending freedom degrees of the streamline section, so that the coupled vibration and the aerodynamic negative damping between different freedom degrees are caused, and the twisting coupled vibration is caused. When the airflow bypasses the section of the blunt body, the flow velocity of the airflow mainly influences or changes the amplitude and phase of the torsional freedom motion of the section of the blunt body, thereby causing torsional vibration and aerodynamic negative damping, and causing torsional vibration. The actual bridge section is between a streamline form and a blunt body, and the vibration form is between torsional vibration and coupling vibration due to different participation degrees of bending degrees of freedom.

The vortex-induced vibration is a nondestructive self-amplitude-limiting wind-induced vibration phenomenon which is easy to occur in a large-span bridge at low wind speed and has the characteristics of both forcing and self-excitation. Severe vertical vortex oscillations have occurred in the gulf channel Bridge of Tokyo (Trans-Tokyo Bay Bridge), the nitylol Bridge of brazil (Rio-niteoi Bridge), and the zonal Bridge of denmark (Great East Belt Bridge). The western-medicine optical-department bridge also has the obvious vertical vortex vibration phenomenon under the condition of low turbulence and under the action of orthogonal wind with the wind speed interval of 9-11 m/s. Although the vortex-induced vibration does not cause divergence like flutter or galloping, the vortex-induced vibration is a vibration which is easy to occur at low wind speed, and the amplitude is large enough to influence the driving safety, and even other types of fatal aerodynamic instability problems such as cable parameter resonance can be induced.

For flutter stability and vortex vibration performance of a large-span bridge, the design Specification for wind resistance of highway bridges (JTG/TD60-01-2004) in China definitely stipulates that: within the service life of the bridge design, the structure should not have destructive self-excited divergent vibration at the maximum wind speed that may occur in the area of the bridge site. The amplitude of the non-destructive wind-induced vibration of the structure should meet the requirements of driving safety, structural fatigue and driving comfort. To the bridge structures that the wind resistance can not satisfy the standard requirement, the standard still stipulates: the wind resistance of the structure can be improved by pneumatic, structural and mechanical means.

The split box girder structure generally comprises two polygonal box-shaped structures which are symmetrical along a central line and are provided with air nozzles, a distance exists between the two polygonal box-shaped structures, and the two polygonal box-shaped structures are connected through a transverse structure. The split box-girder structure is an important flutter control measure for cable bearing bridge and has been widely used, and the cross-section of China western optical gate bridge (the first span in China, 1650m), hong kong manzhou bridge (1018 m) and the Roman bridge (1377 m) are used. Although the section of the box girder in the form has better flutter stability, due to the existence of the gap between the two box girders, the flow field structure around the box girder is extremely complex, the vortex shedding characteristic is obviously enhanced, and the vortex-induced vibration of the main girder is intensified.

At present, the control measures of vortex-induced vibration of the section of a main beam of a split box girder structure are roughly divided into two types: one is a fixed aerodynamic measure, which can be applied to the form of additional components of a large span bridge by changing the aerodynamic profile of the main beam to change the wind load it bears, and generally includes: longitudinal grating, changing groove width and guide plate. As shown in fig. 1, a grid structure (publication number CN201534954U) for controlling vortex-induced vibration of a split-type box girder is provided, wherein a grid structure 1 is arranged at the top of a central slot of the split-type steel box girder, the grid structure 1 comprises a grid 2 and a grid support 3 which are welded together, and vortex generated when air flows through the split-type steel box girder is restrained by the grid structure, so that vortex-induced vibration is controlled. However, although this measure is effective in controlling vortex oscillations, it may adversely affect the flutter performance of the split box beam; the other is TMD, and the working principle of the TMD is to transmit the energy of the structural vibration to the TMD by adjusting the mass, the rigidity and the damping system of the TMD, thereby achieving the purpose of weakening the structural vibration. Fujino developed a TMD control device for controlling vertical vortex vibration of a box girder aiming at vortex-induced vibration occurring in a Tokyo Bay bridge, and the control device was installed on a real bridge to achieve a good control effect. However, for the large-span suspension cable bridge, vortex-induced vibration under different modes often occurs, and the TMD can only control the response of a certain vibration mode, which will severely limit the application of the TMD in the vortex vibration control of the large-span suspension cable bridge. Furthermore, the TMD is heavy in its own weight, which undoubtedly greatly increases the vertical load of the bridge. At present, measures applied to bridge vortex vibration control are generally permanent and have no controllability, the vortex vibration performance of the bridge can be hardly improved under various conditions, and the universality is poor. Furthermore, aerodynamic measures for suppressing vortex oscillations may adversely affect the structure flutter performance.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a bridge flutter and vortex vibration integrated control device and a control method thereof, which solve the technical problems in the existing split bridge structure at present.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme: the utility model provides a bridge flutter and vortex vibration integrated control device, the bridge includes two polygon case roof beams of taking the outside tuyere along the central line symmetry, controlling means includes scalable or pivoted upper and lower apron and is located the inside power device of case roof beam, upper and lower apron is installed the inboard of split type case roof beam opposite face, upper and lower apron can for polygon case roof beam is flexible or rotate.

Furthermore, the power device drives the upper cover plate and the lower cover plate to extend and rotate.

Furthermore, a sliding groove is formed in the polygonal box girder, and the upper cover plate and the lower cover plate are arranged in the sliding groove in a telescopic mode.

Furthermore, the upper cover plate and the lower cover plate can stretch out and draw back different lengths according to the wind power condition, and the maximum length is to completely seal the split type box girder, so that the box girder is integrated.

Further, the control method using the bridge flutter and vortex vibration integrated control device comprises the following steps: 1. under normal conditions, the power device does not work, and the upper cover plate and the lower cover plate are retracted in the sliding groove; 2. when the anemoscope monitors that incoming wind enters a vortex vibration locking area, the power device drives the upper cover plate and the lower cover plate to move, so that the split box girder is combined into the integral box girder.

Furthermore, according to the difference of the incoming wind, the upper cover plate and the lower cover plate can be controlled to be in different telescopic lengths, so that the box girder is in a semi-closed state.

(III) advantageous effects

The telescopic cover plate provided by the invention can be adjusted according to the characteristics of incoming wind, and the adjustment simultaneously ensures the flutter stability and the vortex vibration performance of a large-span bridge.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of a prior art structure for improving the vortex vibration stability of a bridge;

FIG. 2 shows the semi-closed state of the upper cover plate and the lower cover plate of the integrated control device for bridge flutter and vortex vibration according to the embodiment of the invention;

FIG. 3 shows the fully closed state of the upper and lower cover plates of the integrated control device for bridge flutter and vortex vibration according to the embodiment of the invention;

FIG. 4 shows the fully closed state of the upper cover plate and the open state of the lower cover plate of the integrated control device for bridge flutter and vortex vibration according to the embodiment of the invention;

FIG. 5 shows the upper cover plate of the integrated control device for bridge flutter and vortex vibration in an open state and the lower cover plate in a fully closed state;

fig. 6 shows a fully opened state of the upper cover plate and the lower cover plate of the integrated control device for bridge flutter and vortex vibration according to the embodiment of the invention.

In the figure: 1 grid structure, 2 grids and 3 grid supports.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

2-6 are different state diagrams of a split box girder provided with upper and lower cover plates, the bridge comprises two polygonal box girders with outer side tuyeres symmetrical along a center line, the control device comprises telescopic or rotatable upper and lower cover plates and a power device positioned in the box girder, the upper and lower cover plates are installed on the inner sides of the opposite surfaces of the split box girder, and the upper and lower cover plates can be telescopic or rotatable relative to the polygonal box girder; the power device drives the upper cover plate and the lower cover plate to stretch or rotate; a sliding groove is formed in the polygonal box girder, and the upper cover plate and the lower cover plate are arranged in the sliding groove in a telescopic mode; the upper cover plate and the lower cover plate stretch out and draw back different lengths according to the wind power condition, and the maximum length is to completely seal the split box girder, so that the box girder is integrated.

Example model body box girder width 48.78cm, height 5.04cm, upper and lower cover plate maximum elongation can close the upper and lower surfaces.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.

Claims

1. The utility model provides a bridge flutter and vortex vibration integrated control device which characterized in that: the bridge comprises a split box girder consisting of two polygonal box girders which are symmetrical along a central line and are provided with outer side air nozzles, the control device comprises an upper cover plate and a lower cover plate which can be contracted and rotated and a power device which is positioned in the polygonal box girder, the power device drives the upper cover plate and the lower cover plate to be contracted or rotated, the upper cover plate and the lower cover plate are arranged on the inner sides of opposite surfaces of the polygonal box girder of the split box girder, a sliding groove is arranged in the polygonal box girder, and the upper cover plate and the lower cover plate are arranged in the sliding groove in a telescopic manner; the upper cover plate and the lower cover plate can stretch relative to the polygonal box girder; the upper cover plate and the lower cover plate stretch to different lengths according to the wind power condition, and the length is changed from stretching to completely sealing the split box girder and stretching to making the split box girder be in a semi-sealing state.

2. The bridge flutter and vortex vibration integrated control device according to claim 1, characterized in that: the power device drives the upper cover plate and the lower cover plate to stretch.

3. A control method using the integrated control device for the flutter and the vortex of the bridge as claimed in any one of claims 1-2, wherein the method comprises the following steps 1, under the normal condition, the power device does not work, and the upper cover plate and the lower cover plate are retracted in the sliding groove; 2. when the anemoscope monitors that incoming wind enters a vortex vibration locking interval, the upper cover plate and the lower cover plate are driven to move through the power device according to the difference of the incoming wind, and the upper cover plate and the lower cover plate are controlled to be in different telescopic lengths, including telescopic operation until the split box girder is combined into the integral box girder and telescopic operation until the split box girder is in a semi-closed state.