A design method for controlling vertical vortex vibration of bridge and a spring-damper combination device

Abstract

The present invention relates to the technical field of vibration control of engineering structures, and in particular to a design method for controlling vertical vortex vibration of a bridge and a spring damping combination device. A design method for controlling vertical vortex vibration of a bridge comprises the following steps: establishing a finite element model of the bridge and calculating the dynamic characteristics; obtaining the cross-sectional St number of the physical bridge based on the historical data of vortex vibration wind speed and vibration frequency obtained by wind tunnel test monitoring of the environment in which the physical bridge is located or the scaled model corresponding to the physical bridge; determining the frequency range or modal order of the vertical mode of the main beam to be inspected; n ; Establish a damping unit in the finite element model, change the damping coefficient of the damping unit and perform complex modal analysis respectively to determine the optimal damping coefficient of the damper; conduct a wind tunnel test on the scaled model of the bridge, and if the requirements are met, complete the design of the bridge damper; if the requirements are not met, redesign the damper vibration reduction scheme, and loop steps S2 and S3 until the requirements are met.

Description

Technical Field

[0001] The invention relates to the technical field of vibration control of engineering structures, and in particular to a design method for controlling vertical vortex vibration of a bridge and a spring damping combination device. Background Art

[0002] Vortex-induced resonance is a wind-induced vibration phenomenon that often occurs in long-span flexible bridges under normal wind speeds. It is a limited amplitude vibration with self-excited properties. Although vortex-induced resonance does not cause serious damage to the bridge structure like flutter and galloping, it will affect driving safety and comfort. Frequent occurrence may even cause fatigue damage to components.

[0003] At present, the most commonly used control methods for vortex-induced resonance of the main beam are two main means: aerodynamic measures and mechanical measures. Pneumatic measures adjust the aerodynamic shape of the main beam, such as installing guide plates and wind nozzles, adjusting the shape and position of auxiliary facilities such as railings and access roads, etc., to change the flow field around the main beam and the surface wind pressure distribution to achieve the effect of suppressing vortex-induced resonance. Mechanical measures refer to the installation of passive or active vibration reduction devices on the bridge. The vibration reduction devices are mainly passive vibration reduction devices such as TMD (Tuned Mass Damper), and active vibration reduction devices are rarely used.

[0004] Pneumatic measures are easy to construct and install, and the cost is usually low. In addition, pneumatic measures often have a suppressive effect on the vortex-induced resonance of multiple modes of bridges, so they are usually the preferred solution for improving the vortex-induced resonance performance of bridge sections. However, a set of TMDs can only control a single first-order mode. To control multi-order modal vortex-induced resonance, TMDs need to be designed for each controlled mode separately, which increases the difficulty and cost of design, manufacturing and installation.

[0005] However, pneumatic measures also have some shortcomings: First, the current scheme for determining pneumatic measures generally adopts a trial-and-error method, which has a high test cost. Second, vortex-induced resonance is sensitive to the shape of the main beam section, and the test results will be affected by the Reynolds number effect, that is, as the Reynolds number changes, the characteristics of the fluid flow will also change, which will cause a certain degree of failure risk of pneumatic measures. Third, when pneumatic measures do not meet the conditions for engineering implementation, mechanical measures such as installing dampers must be adopted. Summary of the invention

[0006] The purpose of the present invention is to overcome the existing methods of controlling vortex-induced resonance in the prior art. One is to set TMD on the bridge, but a group of TMD can only control a single first-order mode, and vortex-induced resonance includes multiple-order vibration modes, so the design, manufacturing and installation costs of TMD will be increased; the second is to adjust the aerodynamic shape of the main beam, but multiple tests are required to obtain the optimal solution, and the test results will be affected by the Reynolds number effect; third, it is also necessary to take into account the shortcomings of the situation where aerodynamic measures do not meet the conditions for engineering implementation, and provide a design method for controlling the vertical vortex vibration of the bridge and a spring damping combination device.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] In a first aspect, the present invention provides a design method for controlling vertical vortex vibration of a bridge, comprising the following steps:

[0009] S1. Establish a bridge finite element model in the modeling platform based on the physical bridge, and calculate the dynamic characteristics of the bridge finite element model; obtain the cross-sectional St number of the physical bridge based on the historical data of vortex-induced wind speed and vibration frequency obtained from the wind tunnel test monitoring of the environment in which the physical bridge is located or the scaled model corresponding to the physical bridge; determine the frequency range or modal order of the main beam vertical mode that needs to be tested based on the calculation results of the dynamic characteristics of the bridge finite element model and the cross-sectional St number of the physical bridge ;

[0010] S2. According to the deformation requirements, structural characteristics and construction difficulty of the main beam of the physical bridge, a damping unit is established between the bridge tower and the main beam at the corresponding position in the finite element model, the damping coefficient of the damping unit is changed, and complex modal analysis is performed to obtain the damping unit at different installation positions. The curve of structural additional damping ratio-damping coefficient corresponding to the order vibration mode is used to determine the optimal damping coefficient of the damper according to the curve of structural additional damping ratio-damping coefficient;

[0011] S3. According to the result of step S2, dampers are installed at corresponding positions of the scaled bridge model, and a wind tunnel test is performed on the scaled bridge model. If the vibration reduction requirements of the physical bridge are met, the design of the bridge damper is completed; if the vibration reduction requirements of the physical bridge are not met, the damper vibration reduction scheme is redesigned, and steps S2 and S3 are repeated until the vibration reduction requirements of the physical bridge are met.

[0012] The finite element dynamic characteristics of the bridge calculated in step S1 include vibration mode and frequency, etc. The value of is determined according to the actual situation and relevant specifications. If the St number of the bridge section is obtained according to the corresponding historical data of the environment where the physical bridge is located in step S1, a scaled model of the physical bridge needs to be made before the wind tunnel test is carried out before step S3.

[0013] The St number (Strouhal number) is a dimensionless number used to describe periodic phenomena in fluid dynamics, especially in vortex shedding and flow-induced vibration. It is usually used to characterize the relationship between the vortex shedding frequency in fluid flow and the fluid velocity and characteristic length. In this design method, the modal order of vertical vortex-induced resonance that often occurs in the physical bridge is first determined based on the finite element model and the historical monitoring data of the physical bridge, and then the damping unit is set in the finite element model. The position setting of the damping unit is determined according to the actual situation. The damping coefficient of the damping unit is changed to obtain the curve of the structural additional damping ratio-damping coefficient corresponding to different modal orders, and the optimal damping coefficient of the damper is determined according to the curve of the structural additional damping ratio-damping coefficient. Then, according to the optimal damping ratio coefficient and installation position of the damper obtained by simulation, a wind tunnel test is carried out on the scaled model of the bridge to verify whether the optimal damping coefficient and installation position of the damper meet the vibration reduction requirements of the physical bridge.

[0014] Compared with the prior art that directly sets multiple TMD devices on the bridge, this design method first selects the vertical modes where vortex vibration may occur, and then simulates the installation of dampers in the modeling platform according to the selected vertical mode orders, which can reduce the number of dampers installed as much as possible and save the cost of damping design, manufacturing and installation. After the numerical calculation is carried out in the modeling platform, the wind tunnel test is carried out, which reduces the number of trial and error, thereby reducing the cost and cycle of the test; and by setting up dampers for vibration reduction, although the shape of the bridge changes and the Reynolds number changes, the Reynolds number effect will not affect the vibration reduction function of the damper, thereby avoiding the situation where the test results are affected by the Reynolds number effect as much as possible; there is no need to consider whether the aerodynamic measures meet the conditions for engineering implementation. The installation of dampers can not only improve the ability of the bridge to resist vortex-induced resonance, but also improve the performance of the bridge to resist various wind-induced vibrations such as flutter and buffeting.

[0015] Preferably, before step S2, it also includes: calculating the corresponding deformation of the main beam under various load combinations. If the deformation of the main beam under any load combination exceeds the deformation threshold of the corresponding load combination, a stiffness unit is established under the main beam of the bridge finite element model in step S2, and an elastic support member is correspondingly set under the main beam in step S3.

[0016] When the vertical stiffness of the main beam does not meet the requirements of the project, elastic support members are set to compensate for the vertical deformation of the main beam.

[0017] Preferably, if the deformation of the main beam under any load combination exceeds the deformation threshold of the corresponding load combination, a stiffness unit connected in parallel with the damping unit is designed in step S2, and an elastic support member connected in parallel with the damper is designed in step S3.

[0018] Preferably, in step S2, the damping unit is arranged on a cross beam or a cross corbel below the main beam along the transverse direction of the bridge, and the damping unit is located in the cross section of the bridge where the bridge tower is located.

[0019] The cross section of the bridge is the cross section of the bridge along the transverse direction. For a floating suspension bridge, when the main beam undergoes vortex-induced resonance, the main beam around the bridge tower usually has a large relative vertical displacement. Therefore, the damping unit is set in the section where the bridge tower is located, which is conducive to ensuring the vibration reduction effect of the device.

[0020] Preferably, when redesigning the damper vibration reduction scheme in step S3, the number of dampers is increased.

[0021] Preferably, when increasing the number of dampers cannot meet the vibration reduction requirements of the physical bridge, a longitudinal corbel is arranged along the bridge direction, the longitudinal corbel is connected to the bridge tower, and the damper is arranged at the free end of the longitudinal corbel.

[0022] The length of the longitudinal corbel is determined according to actual conditions.

[0023] Preferably, step S3 can also be replaced by: installing dampers at corresponding positions of the physical bridge according to the simulation results of step S2, and monitoring the actual amplitude of the main beam of the physical bridge. If the requirements are met, the design of the bridge damper is completed; if the requirements are not met, the damper vibration reduction scheme is redesigned, and steps S2 and S3 are looped until the vibration reduction requirements of the physical bridge are met.

[0024] By installing a damper on a physical bridge, the maximum vertical amplitude of the main beam and the frequency of the vortex-induced force after the damper is installed can be directly compared with the physical bridge without the damper, which can more intuitively reflect the vibration reduction effect of the damper.

[0025] Preferably, in step S3, the actual measured physical bridge with a damper is The actual amplitude of the first-order vortex vibration and the first-order vortex vibration of the physical bridge Permissible amplitude of vortex vibration For comparison, , if the The actual amplitude of the first-order vortex vibration is less than or equal to , then the vibration reduction requirements of the physical bridge are met, and the allowable amplitude of vortex vibration is Calculated by the following formula:

[0026]

[0027] in, It is The natural frequency of the vertical vortex vibration corresponding to the order vortex vibration mode.

[0028] Preferably, in step S2, when determining the optimal damping coefficient of the damper, when the damper is located at the same installation position, different optimization criteria are used to optimize and calculate the maximum value of the additional damping ratio, and the damping coefficient corresponding to the maximum value of the additional damping ratio is the optimal damping coefficient of the damper.

[0029] The optimization calculation methods include: obtaining The root mean square of the vertical bending mode is taken as the maximum value of the additional damping ratio; The weighted average of the vertical bending modes is taken as the maximum value of the additional damping ratio, where The weights of the vertical bending modes are equal; The weighted average of the first-order vertical bending modes is used as the maximum value of the additional damping ratio, but a larger proportion is given to the vertical bending modes that are prone to occur under the common wind speeds in the environment where the physical bridge is located to obtain the maximum value of the additional damping ratio. The optimization criteria given from the above three perspectives can be flexibly considered in combination with the actual vibration reduction scheme, but are not limited to the optimization criteria of these three perspectives. Since the bridge has multi-order vertical vortex-induced vibration problems, the goal of vortex-induced vibration control cannot be limited to the vibration of a certain order mode. All vibration modes that occur under common wind speeds should be considered, so it is necessary to optimize the calculation of the maximum value of the additional damping ratio.

[0030] In a second aspect, the present invention provides a spring-damping combination device, comprising a damper and a spring, wherein the arrangement of the damper is designed by a design method for controlling vertical vortex vibration of a bridge as described above.

[0031] By designing the damper of the spring-damper combination device through the above method, it is beneficial to reduce the working conditions of the wind tunnel test, thereby reducing the test cost. In addition, by setting the damper through the above method, the construction period is short, and the normal operation of the bridge is avoided as much as possible. In addition, the damper can simultaneously improve the performance of the structure in resisting various wind-induced vibrations such as flutter, vortex-induced resonance and buffeting.

[0032] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0033] 1. A design method for controlling vertical vortex vibration of a bridge of the present invention first determines the modal order of vertical vortex-induced resonance that often occurs in a physical bridge according to the historical monitoring data of the finite element model and the physical bridge, and then sets a damping unit in the finite element model, and the position setting of the damping unit is determined according to the actual situation. The damping coefficient of the damping unit is changed to obtain the curve of the structural additional damping ratio-damping coefficient corresponding to different modal orders, and the optimal damping coefficient of the damper is determined according to the curve of the structural additional damping ratio-damping coefficient. Then, according to the optimal damping ratio coefficient and installation position of the damper obtained by simulation, a wind tunnel test is performed on the scaled model of the bridge to verify whether the optimal damping coefficient and installation position of the damper meet the vibration reduction requirements of the physical bridge. Compared with the prior art that directly sets multiple TMD devices on the bridge, the present design method first selects the vertical mode where vortex vibration may occur, and then simulates the installation of the damper in the modeling platform according to these selected vertical modal orders, which can reduce the number of dampers installed as much as possible and save the cost of damping design, manufacturing and installation. After numerical calculations are performed in the modeling platform, wind tunnel tests are conducted, which reduces the number of trial and error, thereby reducing the cost and cycle of the test; and by setting up dampers for vibration reduction, although the Reynolds number changes due to the shape of the bridge, the Reynolds number effect will not affect the vibration reduction function of the damper, thereby avoiding as much as possible the situation where the test results are affected by the Reynolds number effect; when aerodynamic measures do not meet the conditions for engineering implementation, this design method can also be used to install dampers. Setting up dampers can not only improve the ability of the bridge to resist vortex-induced resonance, but also improve the performance of the bridge to resist various wind-induced vibrations such as flutter and buffeting. This design method overcomes the existing methods of controlling vortex-induced resonance in the prior art. One is to set TMD on the bridge, but a group of TMD can only control a single first-order mode, and vortex-induced resonance includes multiple-order vibration modes, so it will increase the design, manufacturing and installation costs of TMD; the second is to adjust the aerodynamic shape of the main beam, but it takes many tests to get the optimal solution, and the test results will be affected by the Reynolds number effect; the third is when the aerodynamic measures do not meet the conditions for engineering implementation, it is necessary to adopt a better damper mechanical measure to overcome the shortcomings of the vibration reduction solution.

[0034] 2. A spring-damper combination device, comprising a damper, wherein the damper is designed by the above-mentioned design method for controlling vertical vortex vibration of a bridge, which is conducive to reducing the working conditions of the wind tunnel test, thereby reducing the test cost. Moreover, by setting the damper by the above-mentioned method, the construction period is short, and the normal operation of the bridge is avoided as much as possible. Moreover, the damper can simultaneously improve the performance of the structure in resisting various wind-induced vibrations such as flutter, vortex-induced resonance and buffeting. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a design method for controlling vertical vortex vibration of a bridge according to the present invention;

[0036] Figure 2 This is the installation diagram of the damper of the floating main beam Figure 1 (Bridges are equipped with cross beams);

[0037] Figure 3 This is the installation diagram of the damper of the floating main beam Figure 2 (The bridge is not equipped with crossbeams);

[0038] Figure 4 It is a schematic diagram of the installation of a damper for a simply supported main beam or a scheme for improving the vibration reduction effect;

[0039] Icon: 1-spring, 2-damper, 3-crossbeam, 4-bridge tower, 5-main beam, 6-cable, 7-transverse corbel, 8-longitudinal corbel. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0041] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0042] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0043] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0044] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0045] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0046] Example 1

[0047] like Figure 1-Figure 4 As shown, a design method for controlling vertical vortex vibration of a bridge adopted in this embodiment comprises the following steps:

[0048] Ⅰ. Establish a bridge finite element model in the modeling platform based on the physical bridge, and calculate the dynamic characteristics of the bridge finite element model; obtain the cross-sectional St number of the physical bridge based on the historical data of vortex-induced wind speed and vibration frequency obtained from the wind tunnel test monitoring of the environment in which the physical bridge is located or the scaled model corresponding to the physical bridge; determine the frequency range or modal order of the main beam vertical mode to be tested based on the calculation results of the dynamic characteristics of the bridge finite element model, the cross-sectional St number of the physical bridge and the wind speed range specified in the "China Highway Bridge Wind Resistance Design Code" (JTG / T 3360-01-2018) ;

[0049] Calculate the corresponding deformation of the main beam under various load combinations. If the deformation of the main beam 5 under any load combination exceeds the deformation threshold of the corresponding load combination, a stiffness unit is established under the main beam 5 of the bridge finite element model, and an elastic support is set under the main beam 5. If the deformation of the main beam 5 under any load combination exceeds the deformation threshold of the corresponding load combination, a stiffness unit in parallel with the damping unit is designed in the bridge finite element model, and an elastic support in parallel with the damper 2 is designed under the main beam 5 of the physical bridge;

[0050] II. According to the deformation requirements, structural characteristics and construction difficulty of the main beam 5 of the physical bridge, a damping unit is established between the bridge tower 4 and the main beam 5 at the corresponding position in the finite element model, the damping coefficient of the damping unit is changed, and complex modal analysis is performed to obtain the damping unit at different installation positions. A curve of structural additional damping ratio-damping coefficient corresponding to the first-order vibration mode, and determining the optimal damping coefficient of the damper 2 according to the curve of structural additional damping ratio-damping coefficient;

[0051] III. According to the result of step S2, the damper 2 is installed at the corresponding position of the scaled bridge model, and a wind tunnel test is performed on the scaled bridge model. If the vibration reduction requirements of the physical bridge are met, the design of the bridge damper 2 is completed; if the vibration reduction requirements of the physical bridge are not met, the vibration reduction scheme of the damper 2 is redesigned, and steps S2 and S3 are repeated until the vibration reduction requirements of the physical bridge are met.

[0052] Compared with the prior art that directly sets multiple TMD devices on the bridge, this design method first selects the vertical modes where vortex vibration may occur, and then simulates the installation of damper 2 in the modeling platform according to the selected vertical mode orders, which can reduce the number of dampers 2 installed as much as possible and save the cost of damping design, manufacturing and installation. After the numerical calculation is performed in the modeling platform, the wind tunnel test is carried out, which reduces the number of trial and error, thereby reducing the cost and cycle of the test; and by setting damper 2 for vibration reduction, although the change in the shape of the bridge causes the Reynolds number to change, the Reynolds number effect will not affect the vibration reduction function of damper 2, thereby avoiding the situation where the test results are affected by the Reynolds number effect as much as possible; at the same time, in order to avoid the limitation of engineering implementation conditions, a new vibration reduction scheme is provided. Setting damper 2 can not only improve the ability of the bridge to resist vortex-induced resonance, but also improve the performance of the bridge to resist various wind-induced vibrations such as flutter and buffeting.

[0053] Furthermore, in step II, the damping unit is preferentially arranged at the cross section of the bridge where the bridge tower 4 is located below the main beam. If a cross beam 3 is arranged correspondingly below the main beam, the damping unit is arranged at the cross beam 3; if no cross beam 3 is arranged below the main beam, a transverse bracket 7 is arranged below the main beam along the transverse direction of the bridge, and the damping unit is arranged at the free end of the transverse bracket 7. In step S2, when determining the optimal damping coefficient of the damper 2, when the damper 2 is located at the same installation position, the maximum value of the additional damping ratio is optimized and calculated, and the damping coefficient corresponding to the maximum value of the additional damping ratio is the optimal damping coefficient of the damper 2.

[0054] When redesigning the vibration reduction scheme of the damper 2 in step S3, the number of dampers 2 is increased. However, when increasing the number of dampers 2 cannot meet the vibration reduction requirements of the physical bridge, a longitudinal corbel 8 is set along the longitudinal direction of the bridge, the longitudinal corbel 8 is connected to the bridge tower 4, and the damper 2 is set at the free end of the longitudinal corbel 8. The length of the longitudinal corbel 8 is determined according to the actual situation. The length of the longitudinal corbel 8 and the damping coefficient of the damper 2 are changed respectively, and the optimal installation position of the damper 2 is first determined according to the minimum upper limit of the damping coefficient corresponding to the same installation position of the damper 2. Then, when the damper 2 is located in the most preferred installation position, different optimization criteria are used to optimize the calculation of the maximum value of the additional damping ratio. The damping coefficient corresponding to the maximum value of the additional damping ratio is the optimal damping coefficient of the damper 2. The optimization calculation method includes: obtaining The root mean square of the vertical bending mode is taken as the maximum value of the additional damping ratio; The weighted average of the vertical bending modes is taken as the maximum value of the additional damping ratio, where The weights of the vertical bending modes are equal; The weighted average of the first-order vertical bending modes is used as the maximum value of the additional damping ratio, but a larger proportion is given to the vertical bending mode that is prone to occur under the wind speed commonly encountered in the environment where the physical bridge is located to obtain the maximum value of the additional damping ratio. The specific method can be found in the document "Research on the Damping Vibration Reduction System of Multi-order Vertical Vortex-Induced Vibration Tower Beam of Suspension Bridge". However, the length of the longitudinal bracket 8 should also take into account the construction factors.

[0055] Furthermore, step III can be replaced by:

[0056] 1. According to the simulation result of step II, the damper 2 is installed at the corresponding position of the physical bridge, and the actual amplitude of the main beam 5 of the physical bridge is monitored. If the requirements are met, the design of the bridge damper 2 is completed; if the requirements are not met, the damper 2 vibration reduction scheme is redesigned, and steps S2 and S3 are repeated until the vibration reduction requirements of the physical bridge are met.

[0057] 2. According to the simulation results of step II, numerical simulation calculations are performed on the physical bridge in the modeling platform. If the requirements are met, the design of the bridge damper 2 is completed; if the requirements are not met, the damper 2 vibration reduction scheme is redesigned, and steps S2 and S3 are repeated until the vibration reduction requirements of the physical bridge are met.

[0058] In step S3, the actual measured physical bridge with damper 2 is The actual amplitude of the first-order vortex vibration and the first-order vortex vibration of the physical bridge Permissible amplitude of vortex vibration For comparison, , if the The actual amplitude of the first-order vortex vibration is less than or equal to , then the vibration reduction requirements of the physical bridge are met, and the allowable amplitude of vortex vibration is Calculated by the following formula:

[0059]

[0060] in, It is The natural frequency of the vertical vortex vibration corresponding to the order vortex vibration mode.

[0061] In this embodiment, the damper 2 may be a direct energy-consuming damper such as a viscous fluid damper or an eddy current damper.

[0062] Example 2

[0063] A three-tower, four-span (200+850+850+200)m simply supported suspension bridge is taken as an example to illustrate the design method. A three-tower, four-span (200+850+850+200)m simply supported suspension bridge adopts steel-concrete composite beams, the beam section width B and height H are 38m and 3m respectively, and the main cable span ratio is 1 / 9. The bridge has vortex vibration during the construction stage or the bridge operation stage.

[0064] According to the monitoring data of the actual bridge, when the bridge structure vibrates vertically, the average wind speed is between 7.0 and 7.6 m / s, the angle between the wind direction and the bridge axis is about 80 degrees, there is a certain positive attack angle and a small turbulence degree (5.8-7.0%). Taking the fourth-order antisymmetric vertical bending mode as an example, the vibration frequency of the main beam is 0.244 Hz, and the maximum unilateral vortex vibration amplitude is about 50 cm, which exceeds the specification limit of 42.7 cm.

[0065] Step 1. According to the "China Highway Bridge Wind Resistance Design Code" (JTG / T 3360-01-2018) and combined with the monitoring data of physical bridges in recent years, select the mode with excessive vortex vibration amplitude that needs to be controlled within the wind speed range of 5m / s-15m / s. According to the wind speed and vibration frequency of the vortex vibration of the actual bridge, it can be calculated that the St number of the bridge section is 0.105 (with the beam height H as a reference). Use the large-scale commercial software ANSYS to establish a bridge finite element model and calculate the dynamic characteristics of the bridge structure. According to the wind speed and vibration frequency of the vortex vibration of the actual bridge, it can be calculated that the St number (Strouhal number) of the bridge section is 0.105 (with the beam height H as a reference). Based on the structural dynamic characteristics and St number, the frequency range of the vertical mode of the main beam 5 that needs to be inspected is determined to be 0.175Hz~0.525Hz according to the wind speed range specified in the specification;

[0066] Step 2: According to the deformation requirements of the main beam 5 of the physical bridge under various load conditions, it is not necessary to install the spring 1 at the bottom of the main beam 5.

[0067] Step 3, based on the optimized damping parameter results in the literature "Study on multi-order vertical vortex-induced vibration tower beam damping system of suspension bridge" and "Discreteviscous dampers for multi-mode vortex-induced vibration control of long-span suspension bridges": In the actual scheme, after comprehensively considering the structural characteristics and construction difficulty, four dampers 2 are installed on both sides of the middle bridge tower 4 by extending the transverse bracket 7. When the longitudinal distance between the damper installation position and the center line of the bridge tower is 20m, the damping coefficient , it has the best control effect for the 5th to 15th order vertical modes within the target frequency range.

[0068] Step 4: In order to verify the effectiveness of the damping vibration reduction system, the vibration response of the main beam 5 before and after the damper 2 is installed on the real bridge is calculated in the ANSYS model under the vortex excitation model load condition of the simple harmonic form. Taking the fourth-order antisymmetric vertical mode (the 7th-order vertical mode) of the main beam 5 as an example, the frequency of the vortex excitation is 0.242Hz. Referring to the limit value required by the specification, the maximum amplitude of the structure before the installation of the damper 2 is simulated to be 0.42m. After the installation of the damper 2, the amplitude of the 7th-order vertical mode is reduced to 0.09m, and the vibration reduction rate reaches 78.6%. At the same time, based on the method mentioned in the literature "Study on Damping Identification of Long-span Bridges Excited by Continuous Vehicle Jumping", a continuous vehicle jumping excitation test was carried out on the real bridge. It was found that after the installation of the damper 2, the damping ratio of each vertical mode of the bridge was significantly improved, and after long-term health monitoring, no vortex vibration occurred in the real bridge.

[0069] Example 3

[0070] A spring damping combination device includes a damper 2, wherein the arrangement of the damper 2 is designed by a design method for controlling vertical vortex vibration of a bridge as described in Example 1, which is conducive to reducing the working conditions of the wind tunnel test, thereby reducing the test cost. Moreover, by setting the damper 2 by the method described in Example 1, the construction period is short, and the normal operation of the bridge is avoided as much as possible. Moreover, the setting of the damper 2 can simultaneously improve the performance of the structure in resisting various wind-induced vibrations such as flutter, vortex-induced resonance and buffeting.

[0071] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A design method for controlling vertical vortex vibration of a bridge, characterized in that: The following steps are included: S1. Establish a bridge finite element model in the modeling platform based on the physical bridge, and calculate the dynamic characteristics of the bridge finite element model; obtain the cross-sectional St number of the physical bridge based on the historical data of vortex-induced wind speed and vibration frequency obtained from the wind tunnel test monitoring of the environment in which the physical bridge is located or the scaled model corresponding to the physical bridge; determine the frequency range or modal order of the main beam vertical mode that needs to be tested based on the calculation results of the dynamic characteristics of the bridge finite element model and the cross-sectional St number of the physical bridge ; S2. According to the deformation requirements, structural characteristics and construction difficulty of the main beam (5) of the physical bridge, a damping unit is established between the bridge tower (4) and the main beam (5) at the corresponding position in the finite element model, the damping coefficient of the damping unit is changed, and complex modal analysis is performed respectively to obtain the damping unit at different installation positions. A curve of structural additional damping ratio-damping coefficient corresponding to the first-order vibration mode, and determining the optimal damping coefficient of the damper (2) according to the curve of structural additional damping ratio-damping coefficient; S3, installing a damper (2) at a corresponding position of the scaled bridge model according to the result of step S2, and performing a wind tunnel test on the scaled bridge model. If the vibration reduction requirements of the physical bridge are met, the design of the bridge damper (2) is completed; if the vibration reduction requirements of the physical bridge are not met, the vibration reduction scheme of the damper (2) is redesigned, and steps S2 and S3 are repeated until the vibration reduction requirements of the physical bridge are met.

2. A design method for controlling vertical vortex vibration of a bridge according to claim 1, characterized in that: Before step S2, the method further includes: calculating the corresponding deformation of the main beam (5) under various load combinations; if the deformation of the main beam (5) under any load combination exceeds the deformation threshold of the corresponding load combination, a stiffness unit is established under the main beam (5) of the bridge finite element model in step S2, and an elastic support member is correspondingly provided under the main beam (5) in step S3.

3. A design method for controlling vertical vortex vibration of a bridge according to claim 2, characterized in that: If the deformation of the main beam (5) under any load combination exceeds the deformation threshold of the corresponding load combination, a stiffness unit connected in parallel with the damping unit is designed in step S2, and an elastic support member connected in parallel with the damper (2) is designed in step S3.

4. A design method for controlling vertical vortex vibration of a bridge according to any one of claims 1 to 3, characterized in that: In step S2, a damping unit is arranged on a cross beam (3) or a cross bracket (7) below a main beam (5) along a transverse direction of the bridge in a modeling platform, and the damping unit is located in a cross section of the bridge where a bridge tower (4) is located.

5. A design method for controlling vertical vortex vibration of a bridge according to claim 4, characterized in that: When redesigning the vibration reduction scheme of the damper (2) in step S3, the number of the dampers (2) is increased.

6. A design method for controlling vertical vortex vibration of a bridge according to claim 5, characterized in that: When increasing the number of dampers (2) cannot meet the vibration reduction requirements of the physical bridge, a longitudinal corbel (8) is arranged along the bridge direction, the longitudinal corbel (8) is connected to the bridge tower (4), and the damper (2) is arranged at the free end of the longitudinal corbel (8).

7. A design method for controlling vertical vortex vibration of a bridge according to any one of claims 1 to 3, characterized in that: Step S3 can also be replaced by: installing a damper (2) at a corresponding position of the physical bridge according to the simulation result of step S2, and monitoring the actual amplitude of the main beam (5) of the physical bridge. If the requirements are met, the design of the bridge damper (2) is completed; if the requirements are not met, the damper (2) vibration reduction scheme is redesigned, and steps S2 and S3 are looped until the vibration reduction requirements of the physical bridge are met.

8. A design method for controlling vertical vortex vibration of a bridge according to claim 7, characterized in that: In step S3, the actual measured physical bridge with the damper (2) is The actual amplitude of the first-order vortex vibration and the first-order vortex vibration of the physical bridge Permissible amplitude of vortex vibration For comparison, , if the The actual amplitude of the first-order vortex vibration is less than or equal to , then the vibration reduction requirements of the physical bridge are met, and the allowable amplitude of vortex vibration is Calculated by the following formula: in, It is The natural frequency of the vertical vortex vibration corresponding to the order vortex vibration mode.

9. A design method for controlling vertical vortex vibration of a bridge according to any one of claims 1 to 3, characterized in that: In step S2, when determining the optimal damping coefficient of the damper (2), when the damper (2) is located at the same installation position, different optimization criteria are used to optimize and calculate the maximum value of the additional damping ratio, and the damping coefficient corresponding to the maximum value of the additional damping ratio is the optimal damping coefficient of the damper (2).

10. A spring damping combination device, characterized in that: It comprises a damper (2) and a spring (1), wherein the arrangement of the damper (2) is designed by a design method for controlling vertical vortex vibration of a bridge as described in any one of claims 1 to 9.

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