Vortex-induced vibration damper and bridge deck of suspension highway bridge

Abstract

The present invention provides a vortex-induced vibration damper and a deck of a suspension highway bridge. The vortex-induced vibration damper includes a left skeleton structure end and a right skeleton structure end, the left skeleton structure end and the right skeleton structure end are connected by a deck gap guide rail in the middle, on one side of the deck gap guide rail, a load balancing spring is arranged, and on the other side of the deck gap guide rail, a piston damper is arranged. The vortex-induced vibration damper and the deck of the suspension highway bridge provided by the present invention achieve the purpose of actively preventing the occurrence of vortex-induced vibration of the suspension bridge or reducing the amplitude of vortex-induced vibration and accelerating the decay of the amplitude of vortex-induced vibration when vortex-induced vibration occurs.

Description

Technical Field

[0001] The present invention relates to the technical field of suspension bridge design, and particularly to a vortex-induced vibration damper and a deck of a suspension highway bridge. Background Art

[0002] A suspension bridge is a long-span bridge that suspends the deck on suspension cables. The deck is composed of a row of interconnected steel box girders, each of which is suspended on the suspension cables respectively. The two ends of the deck are connected to the crossbeams of the cable towers respectively. Therefore, statically, the deck composed of steel box girders is in a horizontal state (or slightly convex upward). When a vehicle passes through the bridge, the load causes the deck to bend downward (or the convexity becomes smaller). This deformation is jointly formed by the deformation of the suspension cables and the deformation of the steel box girders under stress.

[0003] Under the action of wind, due to the existence of the Karman vortex street phenomenon, the deck of a suspension bridge will vibrate with undulations. When the vortex street frequency is equal to or close to the natural frequency of the bridge body, resonance is formed. This is a forced vibration phenomenon under the action of external forces, namely vortex-induced vibration. When the amplitude reaches a certain level, it will affect traffic safety and even cause damage to the bridge body. If the amplitude of vortex-induced vibration is large and the duration is long, it may trigger flutter of the deck. Flutter has a great destructive effect on the bridge and is something that should be avoided in bridge design. When the external force disappears, due to the low damping coefficient of the suspension bridge, the vortex-induced vibration phenomenon will still continue for some time. Usually, due to the relatively light weight of the bridge body of the suspension bridge and the relatively low natural frequency, steel box girder suspension bridges are prone to vortex-induced vibration.

[0004] Vortex-induced vibration caused by wind is a dynamic vibration phenomenon of deck undulations. The vibration of the steel box girder deck in the vertical direction and the vibration of the suspension cables and hangers in the vertical direction constitute the overall vibration of the bridge. However, the vibration of the deck attracts more attention.

[0005] In solving the problem of vortex-induced vibration of suspension bridges, bridge design experts focus on analyzing and calculating the aerodynamic performance of the bridge during the design of the bridge structure and shape, and at the same time conducting wind tunnel test on the bridge model to minimize the force of the wind on the deck, so that the vortex-induced vibration of the bridge is controlled within the allowable range. However, there is still no method to actively prevent and reduce the occurrence of vortex-induced vibration in the design of steel box girder suspension bridges. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a vortex-induced vibration damper and a deck of a suspension highway bridge, so as to achieve the purpose of actively preventing the occurrence of vortex-induced vibration of the suspension bridge or reducing the amplitude of vortex-induced vibration and accelerating the attenuation of the vortex-induced vibration amplitude when vortex-induced vibration occurs.

[0007] To solve the above technical problems, the present invention provides a vortex-induced vibration damper, which includes: a left skeleton structure end and a right skeleton structure end. The left skeleton structure end and the right skeleton structure end are connected by a bridge deck gap guide in the middle. On one side of the bridge deck gap guide, a load balancing spring is provided. On the other side of the bridge deck gap guide, a piston damper is provided. Moreover, the load balancing spring and the piston damper are respectively fixedly connected to the left skeleton structure end and the right skeleton structure end.

[0008] In some embodiments, the left end of the piston rod is connected to the left skeleton structure end, and a piston is installed at the right end. The right end of the piston cylinder is connected to the right skeleton structure end.

[0009] In some embodiments, the piston cylinder is filled with oil through an oil injection hole.

[0010] In addition, the present invention also provides a suspension bridge deck. A gap is reserved at the cross-section of the bridge deck. The width of the gap is equal to the length of the vortex-induced vibration damper. The vortex-induced vibration damper is installed therein, and the vortex-induced vibration damper is the one described above.

[0011] In some embodiments, the left skeleton structure beam of the vortex-induced vibration damper is fixedly connected to the steel box girder on its left side, and the right skeleton structure beam of the vortex-induced vibration damper is fixedly connected to the steel box girder on its right side.

[0012] In some embodiments, the vortex-induced vibration dampers are distributed in two rows, upper and lower.

[0013] In some embodiments, the vortex-induced vibration dampers are installed between two steel box girders.

[0014] In some embodiments, one or several vortex-induced vibration dampers are installed in each bridge hole.

[0015] After adopting such a technical solution, the present invention has at least the following advantages:

[0016] For the suspension bridge vortex-induced vibration damper designed according to the present invention, the technical solution of installing the damper at the above-mentioned bridge deck gap improves the damping coefficient of the suspension bridge, achieving the purpose of actively preventing the occurrence of vortex-induced vibration of the suspension bridge, reducing the amplitude of vortex-induced vibration and making the vortex-induced vibration decay rapidly when vortex-induced vibration occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, the following further describes the present invention in detail in combination with the drawings and specific embodiments.

[0018] Figure 1a It is a schematic diagram of the suspension bridge deck being horizontal at rest.

[0019] Figure 1bIt is a schematic diagram of the upward convexity of the cable-stayed bridge deck at rest.

[0020] Figure 2 It is a schematic diagram of the mechanical principle of the vortex-induced vibration damper of the cable-stayed bridge.

[0021] Figure 3 It is an assembly schematic diagram of the vortex-induced vibration damper of the cable-stayed bridge.

[0022] Figure 4 It is a unit schematic diagram of the vortex-induced vibration damper of the cable-stayed bridge.

[0023] Figure 5 It is an installation schematic diagram of the vortex-induced vibration damper of the cable-stayed bridge.

[0024] Figure 6a It is a side view of the bridge deck with the vortex-induced vibration damper installed in the middle of the cable-stayed bridge.

[0025] Figure 6b It is a top view of the bridge deck with the vortex-induced vibration damper installed in the middle of the cable-stayed bridge.

[0026] Figure 7a It is a side view of the bridge deck with the vortex-induced vibration damper installed at both ends of the cable-stayed bridge.

[0027] Figure 7b It is a top view of the bridge deck with the vortex-induced vibration damper installed at both ends of the cable-stayed bridge. Specific Embodiments

[0028] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0029] Mechanically, a cable-stayed bridge is a complex suspension system. To solve the vortex-induced vibration problem of the cable-stayed bridge, it is necessary to simplify the mechanical model of the bridge. The method is to simplify the cables, hangers and bridge deck of the cable-stayed bridge into a straight bridge deck, which is fixed to the tower crossbeams at both ends. Analyze the deformation of the bridge deck under the action of load, and the relationship between the vibration process of the bridge deck and the change of the bridge deck length during vortex-induced vibration.

[0030] Assume that the bridge deck between the two towers is in a horizontal state without load, and its distance is Lb, as shown by the horizontal black solid line in Figure 1a When fully loaded, the bridge deck bends slightly downward by an amplitude of a, as shown by the black solid line arc in Figure 1a During vortex-induced vibration, the bridge deck undergoes undulating vibration. If vortex-induced vibration occurs at rest (without load), the horizontal bridge deck vibrates up and down between the thin solid lines on both sides of the horizontal black solid line, and the double amplitude is 2a1; if vortex-induced vibration occurs when fully loaded, the bridge deck vibrates between the thin solid lines on both sides of the black solid line arc, and the double amplitude is 2a1. Figure 1b The bridge deck in

[0031] It can be seen that whether it is a load or vortex-induced vibration, elastic deformation will cause the length of the bridge deck to increase (the undulation of the bridge deck changes the bridge deck from a horizontal straight line to an arc). If the distance between the two pylons remains unchanged, when a load or vortex-induced vibration occurs and the bridge deck becomes longer, it will inevitably cause the bridge deck to bend. The load can only make the bridge deck bend downward, while the vortex-induced vibration causes the undulating vibration of the bridge deck. In Figure 1a , it can be calculated that when the bridge deck bends downward slightly by an amplitude of a under full load, the elongation of the bridge deck is d; when the double amplitude of the vortex-induced vibration is 2a1, the elongation of the bridge deck is 2d1; when vortex-induced vibration occurs when the bridge is fully loaded and the maximum amplitude is a + a1 from the horizontal bridge deck, the elongation of the bridge deck is d + d1.

[0032] If a gap with a width of L is reserved at a certain cross-section of the bridge deck when the bridge deck is static for installing the vortex-induced vibration damper, and the static length of the vortex-induced vibration damper is also L, as Figure 2 . The vortex-induced vibration damper is elastic, that is, there is a spring in the horizontal direction in the vortex-induced vibration damper, which is called the load balancing spring here and can be stretched or compressed under the action of a horizontal force. Then when the suspension bridge undergoes elastic deformation along the length direction of the bridge deck under the action of a load or wind force, it will cause the length L of the vortex-induced vibration damper to change. If the bridge deck becomes longer, the vortex-induced vibration damper is subjected to a horizontal pressure and the length L becomes smaller; if the bridge deck becomes shorter, the vortex-induced vibration damper is subjected to a horizontal tension and the length L becomes longer. The change in the length of the bridge deck and the change in the length of the load balancing spring cancel each other out, and the total change in the length of the bridge deck will be kept reduced or unchanged. Then the bridge deck will not undergo undulating vibration. This spring is an important component of the vortex-induced vibration damper. However, only having this characteristic cannot achieve the purpose of reducing the amplitude of vortex-induced vibration and making the amplitude of vortex-induced vibration decay rapidly or even preventing the occurrence of vortex-induced vibration. Because the restoring force of the spring will cause the bridge deck to continue to vibrate or even make the vibration intensify. Therefore, in principle, a complete vortex-induced vibration damper must have a damping device (damper). The damper is installed side by side with the spring in the vortex-induced vibration damper, as Figure 2 . In this way, mechanically, the load balancing spring, the damper (the two constitute the vortex-induced vibration damper) and the bridge deck form a second-order damped vibration system. The damper has the function of absorbing vibration energy, reducing the amplitude of the system or preventing the system from vibrating.

[0033] The maximum allowable change in the length of the bridge deck is d + d1, which is an important given parameter for the design of the vortex-induced vibration damper.

[0034] If the bridge deck bulges upward when it is static and the load makes the bridge deck sink to a nearly horizontal state, see Figure 1b , when there is a load or vortex-induced vibration, the length of the bridge deck does not increase but decrease, only the spring is compressed or stretched differently, which does not affect the above analysis results.

[0035] Structurally, the vortex-induced vibration damper is also part of the bridge deck and deforms and vibrates together with the bridge load and the bridge deck. Therefore, the vortex-induced vibration damper must also have a bridge deck gap guide rail, the function of which is to ensure that the vortex-induced vibration damper only makes opening and closing movements along the length direction of the bridge deck.

[0036] Using the suspension bridge vortex-induced vibration damper designed according to the present invention, the method of installing the damper at the above-mentioned bridge deck gap improves the damping coefficient of the suspension bridge, achieving the purpose of actively preventing the occurrence of vortex-induced vibration of the suspension bridge, reducing the amplitude of vortex-induced vibration and quickly attenuating the vortex-induced vibration when it occurs.

[0037] See Figure 2 , at a certain cross-section of the bridge deck, a gap with a width of L is reserved for installing the vortex-induced vibration damper, and the static length of the vortex-induced vibration damper is also L.

[0038] At a certain cross-section of the bridge deck, a gap with a width of L is reserved for installing the vortex-induced vibration damper, and the static length of the vortex-induced vibration damper is also L. 23 and 24 represent the two sides of the bridge deck. 21 represents the spring, and 22 represents the damper.

[0039] Figure 3 It is a schematic assembly diagram of the vortex-induced vibration damper. Figure 3 The vertical direction of is the bridge width direction with a bridge width of W, and the left and right direction is the bridge length direction, top view. The length of the vortex-induced vibration damper is L, which is consistent with the bridge length direction, and the width of the vortex-induced vibration damper is equal to the bridge width.

[0040] The vortex-induced vibration damper is composed of N vortex-induced vibration damper units, and the unit length is M. N load-balancing springs jointly bear the telescopic deformation caused by the bridge load and vibration, N piston dampers jointly bear the damping task of the bridge vibration, and N guide rails limit the bridge deck to slide only in the bridge length direction, forming an integral suspension bridge vortex-induced vibration damper as Figure 3 .

[0041] Figure 3 The maximum displacement along the bridge deck direction that the integral vortex-induced vibration damper in can withstand is determined by the piston stroke of the piston damper, the guide rail stroke, and the linear deformation stroke of the spring.

[0042] The N vortex-induced vibration damper units are distributed in two rows, upper and lower, which is beneficial to improving the structural strength. Figure 3 Only one row is drawn in the schematic diagram.

[0043] The left skeleton structural beam 31 of the vortex-induced vibration damper is installed and connected to the steel box girder on its left side, and the right skeleton structural beam 32 of the vortex-induced vibration damper is installed and connected to the steel box girder on its right side. The N vortex-induced vibration damper units are installed on these two beams. The vortex-induced vibration damper is also part of the bridge deck.

[0044] The vortex-induced vibration dampers of the suspension bridge can be installed between two steel box girders. One or several dampers are installed in each bridge opening, which is determined by the engineering design.

[0045] For the vortex-induced vibration dampers in each bridge opening of each bridge, the allowable displacement along the bridge deck direction that the whole can withstand and the damping coefficient that the bridge should reach are determined according to the requirements of the vortex-induced vibration resistance index of the suspension bridge.

[0046] The vortex-induced vibration dampers of the suspension bridge need to be realized through engineering design for each bridge, and the integration and suspension problems between the vortex-induced vibration dampers of the suspension bridge and the steel box girders on both sides need to be solved.

[0047] Figure 4 It is a schematic diagram of the vortex-induced vibration damper unit. The vortex-induced vibration damper of the suspension bridge consists of N vortex-induced vibration damper units. Each vortex-induced vibration damper is composed of three parts: a load balancing spring 41, piston dampers (44, 45, 48, 49, 40), and bridge deck gap guides (42, 43). There are two left and right skeleton structure ends 46 and 47 in the structure of the vortex-induced vibration damper unit. The load balancing spring 41 and the piston dampers are installed on the two skeleton ends, and then are installed together with Figure 3 the skeleton structure beams 31 and 32 in

[0048] The load balancing spring 41 is in a free state statically, without being subjected to or slightly subjected to tensile or compressive forces. The two ends are fixed on the skeleton structure ends of the damper. The balancing spring should be able to withstand tensile deformation and compressive deformation. In the case shown in the figure, the balancing spring mainly withstands compressive deformation.

[0049] The piston dampers 44, 45, 48, 49, and 40 form a piston damper. The left end of the piston rod 45 is connected to the left skeleton structure end 46, and the right end is equipped with a piston 49. The right end of the piston cylinder 40 is connected to the right skeleton structure end 47. The piston cylinder is filled with oil through the oil injection hole, and the oil injection hole is sealed. When the left and right beams move relative to each other, the piston slides left and right in the piston cylinder. Because there are small holes on the piston that communicate left and right, it is inevitable that the oil in the cylinder flows from the left side of the piston cylinder to the right side or from the right side of the piston cylinder to the left side through the small holes on the piston, which generates resistance to the movement of the bridge deck. The smaller the small holes on the piston, the greater the damping force, and the greater the change speed of the bridge deck gap width, the greater the damping force, that is, the greater the damping coefficient of the bridge. By changing the area of the small holes on the piston and controlling the gap between the piston and the piston cylinder, the damping coefficient of the suspension bridge can be controlled. This damping force consumes the kinetic energy of the bridge vibration. An appropriate damping coefficient can make the vibration of the bridge stop quickly, and has the ability to prevent and reduce the occurrence of vortex-induced vibration of the suspension bridge, thus protecting the bridge.

[0050] The bridge deck gap guide rail. Since there is relative movement between the left and right skeleton installation beams of the suspension bridge anti-vortex-induced vibration damper, under the action of external forces, it may cause the two skeleton installation beams to have relative displacement (dislocation) transversely on the bridge deck, which will damage the load balance spring and the piston damper, thus causing damage to the bridge deck. That is to say, structurally, the left and right skeleton installation beams of the suspension bridge anti-vortex-induced vibration damper can only slide along the left and right directions (the bridge deck extension direction), and cannot have transverse dislocation on the bridge deck, nor can the bridge deck collapse under load. This requires installing a guide rail along the bridge deck direction between the two skeleton installation beams. This guide rail ensures that the skeleton installation beams can only slide along the left and right horizontal directions.

[0051] Figure 4 Figures 42 and 43 are schematic diagrams of the sleeve-type guide rail. The left end of the outer sleeve 42 is connected to the left skeleton structure end 46, and the right end of the inner sleeve 43 is connected to the right skeleton structure end 47. The guide rail can ensure that the left and right skeleton structure ends can only slide along the axis direction of the guide rail. In engineering, the bridge deck gap guide rail can be taken out from the anti-vortex-induced vibration damper unit, integrally designed in the anti-vortex-induced vibration damper, and a maximum displacement limiting device is provided.

[0052] Figure 5 is a schematic diagram of the installation of the suspension bridge anti-vortex-induced vibration damper. Assembling N anti-vortex-induced vibration damper units with the left and right two skeleton beams 51 and 52 together to form the suspension bridge anti-vortex-induced vibration damper as Figure 3 . The assembled suspension bridge anti-vortex-induced vibration damper is convenient for overall installation in the bridge deck gap L.

[0053] Figure 6a and Figure 6b is a schematic diagram of the installation of the suspension bridge anti-vortex-induced vibration damper in the middle of the suspension bridge. Figure 6a is a side view of the bridge deck, where 61 represents the suspension bridge anti-vortex-induced vibration damper and 62 represents the seamless expansion joint. Figure 6b Schematically shows the installation of the suspension bridge anti-vortex-induced vibration damper in the middle of the suspension bridge. The dimension L is actually about one-tenth of the length of a single steel box girder. For clarity, L is enlarged in the figure.

[0054] Figure 7a and Figure 7b are schematic diagrams of the installation of the suspension bridge anti-vortex-induced vibration damper at both ends of the suspension bridge. Figure 7a is a test diagram of the bridge deck, where 71 represents the suspension bridge anti-vortex-induced vibration damper and 72 represents the seamless expansion joint. Figure 7b Schematically shows the installation of two suspension bridge anti-vortex-induced vibration dampers at both ends of the suspension bridge deck. The dimension L is actually about one-tenth of the length of a single steel box girder. For clarity, L is enlarged in the figure.

[0055] Embodiment 1

[0056] Figure 6 is a schematic diagram of the installation of the vortex-induced vibration damper of the suspension bridge in the middle of the suspension bridge. Since the vortex-induced vibration damper of the suspension bridge has the same width as the bridge deck and its length is about one-tenth of the length of a steel box girder, the vortex-induced vibration damper of the suspension bridge can be installed between two steel box girders in the middle of the bridge. Because above the vortex-induced vibration damper of the suspension bridge is a part of the bridge deck and there is a telescopic gap, a seamless expansion joint must be installed to ensure the passability of the bridge deck. The seamless expansion joint is a mature technology in bridge design and can be solved during the engineering design. The possibility of installing the vortex-induced vibration damper of the suspension bridge at other cross-sections of the bridge deck cannot be excluded.

[0057] Embodiment 2

[0058] Figure 7 is a schematic diagram of the installation of the vortex-induced vibration damper of the suspension bridge at both ends of the suspension bridge. When the span of the suspension bridge is very large, one vortex-induced vibration damper of the suspension bridge is installed near each of the bridge towers of the bridge, which can increase the damping coefficient of the bridge and improve the anti-vortex-induced vibration performance. Similar to Embodiment 1, because above the vortex-induced vibration damper of the suspension bridge is a part of the bridge deck and there is a telescopic gap, a seamless expansion joint must be installed to ensure the passability of the bridge deck. The seamless expansion joint is a mature technology in bridge design and can be solved during the engineering design.

[0059] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modifications, equivalent changes or decorations made by those skilled in the art using the disclosed technical content all fall within the protection scope of the present invention.

Claims

1. A deck of a suspension highway bridge, characterized in that A gap is reserved at the cross-section of the bridge deck. The width of the gap is equal to the length of the vortex-induced vibration damping device, and the vortex-induced vibration damping device is installed therein. The left skeleton structure beam of the vortex-induced vibration damping device is fixedly connected to the steel box girder on its left side, and the right skeleton structure beam of the vortex-induced vibration damping device is fixedly connected to the steel box girder on its right side. The vortex-induced vibration damping device includes a left skeleton structure end and a right skeleton structure end. The left skeleton structure end and the right skeleton structure end are connected by a bridge deck gap guide rail in the middle. On one side of the bridge deck gap guide rail, a load balancing spring is provided. On the other side of the bridge deck gap guide rail, a piston damper is provided. Moreover, the load balancing spring and the piston damper are respectively fixedly connected to the left skeleton structure end and the right skeleton structure end.

2. The bridge deck of the suspension highway bridge according to claim 1, characterized in that, The vortex-induced vibration damping devices are distributed in two rows up and down.

3. The bridge deck of the suspension highway bridge according to claim 1, wherein The vortex-induced vibration damping devices are installed between two steel box girders.

4. The deck of the suspension highway bridge according to claim 3, characterized in that, One or several vortex-induced vibration damping devices are installed in each bridge opening.

5. The deck of the suspension highway bridge according to claim 1, characterized in that The left end of the piston rod is connected to the left skeleton structure end, and a piston is installed at the right end. The right end of the piston cylinder is connected to the right skeleton structure end.

6. The deck of the suspension highway bridge according to claim 1, wherein The piston cylinder is filled with oil through the oil filling hole.

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