Cable support friction energy dissipation system for controlling wind-induced and vehicle-induced vibration of long-span bridges

Abstract

The present application belongs to the technical field of bridge vibration control, and provides a cable support friction energy dissipation system for controlling wind vibration and vehicle vibration of a large-span bridge, comprising upper cables, lower cables, vertical hangers, oblique hangers, a sheath and a friction energy dissipation device. The upper cables, the lower cables, the vertical hangers and the oblique hangers form a high-altitude large-span large-rigidity cable support friction energy dissipation system which is simple in structure, convenient in construction, light in weight, high in strength, scientific in stress, and high in economy. The cable support friction energy dissipation system does not need to be tuned and has strong robustness. Relative displacement occurs between the bridge vibration and the cable system, friction energy is generated, thus the vortex vibration, buffeting, vehicle vibration of the bridge at any frequency and any mode can be greatly reduced, and the service performance of the bridge is improved. Due to the constraint effect of the cable system on the main beam, the static wind displacement of the bridge can also be reduced, and the critical wind speed of static wind instability and the critical wind speed of flutter of the bridge are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of bridge vibration control, and particularly relates to a cable support friction energy dissipation system for controlling wind vibration and vehicle vibration of a long-span bridge. BACKGROUND

[0002] A long-span bridge structure is light and flexible, and is relatively sensitive to wind load. At low wind speed, the bridge may have obvious vortex vibration and buffeting, affecting driving comfort and safety; under strong wind action, the bridge may have single-degree-of-freedom torsional or bending-torsional coupled flutter, resulting in severe vibration of the bridge or even collapse and damage. Therefore, appropriate measures must be taken to ensure the wind resistance safety of the long-span bridge. Current bridge wind vibration control measures are generally divided into aerodynamic measures, mechanical measures and structural measures.

[0003] The aerodynamic measures improve the wind resistance performance of the bridge by improving the aerodynamic shape of the main girder section, such as adding a wind nozzle, a flow guide plate, a central stabilizing plate or using a central slotted section. For an ultra-long-span bridge, the aerodynamic measures have limited control effect on vortex vibration, and some aerodynamic optimization schemes (such as a slotted central section of the main girder) may cause new or more serious vortex vibration problems, increasing the vibration risk of the bridge.

[0004] The mechanical measures mainly use a tuned mass damper (TMD), a multiple tuned mass damper (MTMD) and a viscous damper. The TMD has good control effect on vortex vibration of a certain order, but more TMDs of different frequencies are needed to control multi-order vortex vibration, resulting in a sharp increase in cost, and the TMD has no obvious control effect on bridge flutter. In addition, such devices are sensitive to the vibration frequency of the bridge, the control of low-frequency vortex vibration is not enough in the vertical space of the main girder, the displacement response of the mass block is too large, resulting in reduced practicability, and the cost increases significantly with the increase of the span.

[0005] The structural measures mainly increase the overall stiffness of the structure by increasing the amount of material or the number of supports to improve the wind resistance performance of the bridge. However, these measures result in a sharp increase in cost, so the structural measures are usually not the first choice for improving the wind resistance performance of the bridge.

[0006] The structure of a long-span bridge is relatively flexible, and various wind vibrations (flutter, vortex vibration, buffeting) and vehicle-bridge coupled vibration problems are more prominent. The above-mentioned traditional wind vibration control measures are difficult to efficiently control various vibrations, and are high in cost. Therefore, it is urgent to develop a control device that can comprehensively cope with various wind vibrations and vehicle vibrations and has more superior economic performance.

[0007] Based on the above situation, the cable support energy dissipation system for controlling wind vibration and vehicle vibration of long-span bridge is provided, which has simple structure, small self-weight, large rigidity, low cost, good robustness, high efficiency, can greatly reduce the multi-modal vortex vibration and buffeting response of the bridge, can also reduce the dynamic response of the bridge caused by driving, improve the driving comfort and safety, and has certain control effect on the flutter of the bridge in extreme cases. SUMMARY

[0008] The cable support friction energy dissipation system for controlling wind vibration and vehicle vibration of long-span bridge is provided. High-strength cables are arranged between the pylon (or arch rib) of a cable-stayed bridge or suspension bridge and the anchor points of the side span, and between the pylon (or arch rib) and the anchor points of the side span. A plurality of vertical or inclined hangers with sufficient pre-tension connect and tighten the high-strength cables arranged above and below to ensure that the upper and lower cables have sufficient tension, thereby achieving sufficient vertical, lateral and longitudinal rigidity. Some vertical hangers link the upper and lower high-strength cables with the main beam through the preformed holes of the main beam or the outrigger devices on both sides of the main beam. When the main beam of the bridge vibrates vertically or torsionally under the action of wind load or vehicle load, the main beam and the hangers passing through the main beam displace relative to each other, and the friction device between the main beam and the hangers dissipates energy to suppress the vibration of the bridge. The connection between the hangers and the main beam can also contribute to reducing the static wind displacement of the main beam.

[0009] Technical scheme of the present application:

[0010] The cable support friction energy dissipation system for controlling wind vibration and vehicle vibration of long-span bridge comprises upper cables 1, lower cables 2, vertical hangers 3, inclined hangers 4, sheaths 5 and friction energy dissipation devices 6.

[0011] In the longitudinal direction, the upper cables 1 and the lower cables 2 are erected between the pylon of a cable-stayed bridge, the pylon of a suspension bridge or the arch rib of an arch bridge, and between the pylon of a cable-stayed bridge, the pylon of a suspension bridge, the arch rib of an arch bridge and the anchor points of the side span; in the vertical direction, the upper cables 1 and the lower cables 2 are located above and below the main beam of the bridge, respectively; in the lateral direction, the upper cables 1 and the lower cables 2 are symmetrically erected on both sides of the main beam of the bridge.

[0012] A plurality of vertical hangers 3 and oblique hangers 4 are arranged at different positions along the bridge span to connect and tension the upper cable 1 and the lower cable 2, so that the cable system composed of the upper cable 1, the lower cable 2, the vertical hanger 3 and the oblique hanger 4 has sufficient vertical, lateral and longitudinal stiffness to provide strong support for wind vibration or vehicle vibration suppression of the bridge girder in the air; the vertical hanger 3 passes through the hole located in the interior of the bridge girder or the hole of the outrigger on both sides of the bridge girder, and a protective sheath 5 is wrapped outside the vertical hanger 3 to play a protective role; a friction energy dissipation device 6 is installed at the hole of the bridge girder where the vertical hanger 3 is installed, and the protective sheath 5 and the friction energy dissipation device 6 are pressed tightly. Under the action of wind load or vehicle load, the bridge girder may vibrate vertically or torsionally in multiple modes, the friction energy dissipation device 6 installed at a plurality of positions on the girder and the vertical hanger 3 vibrate vertically, and the friction energy dissipation device 6 and the protective sheath 5 generate friction and energy dissipation, thereby effectively suppressing the vibration of the bridge.

[0013] The upper cable 1, the lower cable 2, the vertical hanger 3 and the oblique hanger 4 have sufficient strength, stiffness and durability, and are as light as possible, convenient to install, and can use carbon fiber materials with a tensile strength higher than 500Mpa, and the materials, sizes and forms are not limited.

[0014] The vertical spatial shape and anchoring position of the upper cable 1 and the lower cable 2 are not limited, and can be determined by comprehensively considering factors such as span, vertical stiffness requirement, modeling beauty, and navigation under the bridge; the larger the rise-span ratio, the greater the stiffness; the greater the stress, the greater the stiffness;

[0015] The main purposes of the vertical hanger 3 and the oblique hanger 4 include two aspects, one aspect is to connect the upper cable 1 and the lower cable 2 to form a cable system, and the vertical, lateral and longitudinal stiffness is much greater than the sum of the vertical, lateral and longitudinal stiffness of the upper cable 1 and the lower cable 2 alone, thereby providing very large vertical, lateral and longitudinal stiffness support for the bridge girder by very small area upper cable 1 and lower cable 2; the other aspect is to provide a force point for the friction energy dissipation device 6 suspended in the air to suppress various vibrations of the girder;

[0016] The number of the vertical hanger 3 and the oblique hanger 4 is not limited, in general, the more the number, the more the mode order that can be controlled, and the better the control effect; the cable system is generally arranged on both sides of the girder, and for the central slot girder section, if there is no need to control torsional vibration, it can also be arranged at the central slot. Under the action of strong wind, the girder will usually produce large static wind displacement, especially lateral displacement, at this time the cable system can also effectively limit the displacement of the girder.

[0017] The protective sheath 5 tightly wraps the vertical hanger 3 to play a protective role, and should have sufficient strength, stiffness and durability, and the materials, sizes and forms are not limited.

[0018] The friction energy dissipation device 6 should have sufficient strength, rigidity, wear resistance and high friction coefficient, and the material, size and form are not limited.

[0019] The friction between the sheath 5 and the friction energy dissipation device 6 can be optimized according to the need, and the friction is too small (extreme case is no friction), and the energy dissipation is too small (extreme case is no energy dissipation), and the vibration suppression effect is not obvious; the friction is too large (extreme case is no relative sliding between the main beam and the vertical sling 3), the main beam drives the cable system to vibrate (because the stiffness of the cable system is far smaller than the stiffness of the bridge system), the cable system mainly plays a role of stiffness support, and the energy dissipation is very small, and the control effect is also good.

[0020] Generally speaking, the larger the area of the upper cable 1 and the lower cable 2, the larger the stress, the larger the space support stiffness that can be provided for the bridge, and the better the vibration control effect, and the higher the cost. The smaller the length of the vertical sling 3, the greater the tensile stiffness, the more favorable to vibration control, but since the material consumption is relatively far smaller than that of the upper cable 1 and the lower cable 2, the cost ratio is very small, so the parameter is not a key design index. The more the number of the inclined slings 4, the larger the area, the better the vibration control effect, and the higher the cost, which can be optimized and designed.

[0021] The cable support system forms a high-altitude large-span large-stiffness support system with simple structure, convenient construction, light weight, high strength, scientific stress and economic efficiency through the upper and lower reverse cables and the vertical / inclined slings. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a whole schematic diagram of a cable support friction energy dissipation system for controlling wind vibration and vehicle vibration of a large-span bridge.

[0023] Figure 2 It is a schematic diagram of the friction energy dissipation device located in the main beam.

[0024] Figure 3This is a schematic diagram of the friction energy dissipation device located on the outer cantilever of the main beam.

[0025] In the diagram: 1. Upper cable, 2. Lower cable, 3. Vertical sling, 4. Angled sling, 5. Sheath, 6. Friction energy dissipation device. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the technical solutions and accompanying drawings.

[0027] like Figure 1 As shown, a cable-supported friction energy dissipation system for controlling wind-induced vibration and vehicle-induced vibration in long-span bridges includes an upper cable 1, a lower cable 2, a vertical suspender 3, an inclined suspender 4, a sheath 5, and a friction energy dissipation device 6.

[0028] Taking a long-span bridge with two towers as an example, the upper cable 1 and the lower cable 2 are longitudinally erected between the towers and between the towers and the side span anchor points, vertically located above and below the main beam, and symmetrically erected on both sides of the main beam laterally. A number of vertical suspenders 3 and diagonal suspenders 4 are set at different positions along the bridge span to connect and tension the upper cable 1 and the lower cable 2. The vertical suspenders 3 pass through holes located inside the main beam or through holes in the outriggers on the outside of the main beam. The larger the lateral spacing of the vertical suspenders 3 on both sides of the main beam, the better the effect on controlling torsional vibration. A sheath 5 is wrapped around the vertical suspenders 3. A friction energy dissipation device 6 is installed at the holes where the vertical suspenders 3 pass through the main beam. The sheath 5 and the friction energy dissipation device 6 are pressed together to ensure reliable force transmission and friction energy dissipation. This can suppress wind-induced or vehicle-induced multimodal vibrations of long-span bridges, reduce static displacement, and improve service performance.

[0029] The above description is merely a preferred embodiment of the present invention and should not be considered as any limitation thereof. Any equivalent changes, modifications, or improvements made by those skilled in the art to the above embodiments when utilizing the technical solutions of the present invention should be considered as falling within the protection scope of the present invention.

Claims

1. A cable supported friction energy dissipation system for controlling wind and vehicle induced vibrations of long span bridges, characterized in that, The cable support friction energy dissipation system comprises upper cables (1), lower cables (2), vertical hangers (3), oblique hangers (4), sheaths (5) and friction energy dissipation devices (6); In the longitudinal direction, the upper cables (1) and the lower cables (2) are arranged between the pylon of a cable-stayed bridge, the pylon of a suspension bridge or the arch rib of an arch bridge, and between the pylon of a cable-stayed bridge, the pylon of a suspension bridge, the arch rib of an arch bridge and the anchorage point of a side span; in the vertical direction, the upper cables (1) and the lower cables (2) are arranged above and below the main girder of the bridge respectively; in the lateral direction, the upper cables (1) and the lower cables (2) are symmetrically arranged on both sides of the main girder of the bridge; A plurality of vertical hangers (3) and oblique hangers (4) are arranged at different positions along the side span, and the upper cables (1) and the lower cables (2) are connected and tensioned, so that the upper cables (1), the lower cables (2), the vertical hangers (3) and the oblique hangers (4) form a cable system; the vertical hangers (3) pass through the holes in the main girder of the bridge or the outriggers on both sides of the main girder of the bridge, and the sheaths (5) are wrapped outside the vertical hangers (3) to play a protective role; the friction energy dissipation devices (6) are arranged at the holes in the main girder of the bridge where the vertical hangers (3) are arranged, and the sheaths (5) and the friction energy dissipation devices (6) are compressed.

2. The cable support friction energy dissipation system for controlling wind and vehicle vibrations of long span bridges according to claim 1, characterized in that, The upper cables (1), the lower cables (2), the vertical hangers (3) and the oblique hangers (4) are made of a material with a tensile strength higher than 500 MPa.

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