Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
  • E01D19/00—Structural or constructional details of bridges
  • E01D19/16—Suspension cables; Cable clamps for suspension cables ; Pre- or post-stressed cables
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
  • E01D11/00—Suspension or cable-stayed bridges
  • E01D11/04—Cable-stayed bridges

Definitions

• the present invention relates to devices for damping the vibrations of a shroud ply of a construction work and to damping methods in which the damping of vibrations of the shroud ply is carried out by means of such devices. More particularly, the damping device according to the invention can in particular serve to dampen the vibrations of a web of guy wires of a construction work such as a guyed bridge.
• the cables forming the cable layer are generally anchored at their upper end on a pylon and at their lower end on the bridge deck. The cable shroud thus ensures the maintenance and stability of the structure.
• the shrouds can accumulate energy and oscillate significantly.
• the two main causes of these vibrations are the displacement of the shroud anchors relative to the deck under the effect of traffic loads, and the effect of the wind acting directly on the shrouds.
• These oscillations when they are not controlled, are likely to directly damage the shrouds, while causing concern for users on the bridge deck.
• interconnection cables which make it possible to connect together a plurality of shrouds of the same layer of shrouds, these cables d interconnection being further directly anchored to the bridge deck.
• interconnection cables make it possible to stiffen the entire set of guy lines while making it possible to prohibit certain modes of vertical vibration of said guy lines.
• the following parameters should be taken into account: - the cross-section, stiffness and tension of the interconnection cables must be determined by a calculation d 'the set of interconnected cable stays; - the resistance of the interconnection cables and their anchors must be adapted to extreme load cases such as road traffic on the bridge deck or a turbulent wind on one structure or on the shrouds; - the pretensioning of the interconnection cables must make it possible to avoid any tensioning under extreme load; indeed, a relaxed interconnection cable no longer plays its role and may be subjected to shocks harmful to the durability of the anchorages, which is also likely to cause said interconnection cable to break and therefore to be replaced by another cable d 'interconnection having a higher section and rigidity while being stretched to a higher tension value; - the angular fractures of the ends of the shroud
• interconnection cables are sometimes used formed from a plurality of strands which are wound around a polymer core, each strand itself formed by a plurality of metallic wires.
• the use of such strands wound around a polymer core gives a low stiffness and a high damping power to the interconnection cable when the latter is subjected to a variable tension.
• these twisted interconnection cables have a significant impact on the geometry of the interconnected shrouds.
• Another solution consists in using dampers arranged between the shrouds and the structure of the structure, these dampers being able to dissipate the vibrational energy of the shrouds.
• shock absorbers are described in particular in documents FR 2 631 407 and FR 2 664 920. To be effective, these shock absorbers must act between a fixed point linked to the structure, generally the deck, and a movable point of the corresponding shroud. For practical reasons, these shock absorbers are placed near the lower or upper anchoring of the corresponding shroud, but their damping power is considerably limited by the small amplitude of movement of the ends of the shrouds near their anchoring.
• the present invention aims in particular to overcome the aforementioned drawbacks.
• the subject of the invention is a device for damping the vibrations of a ribbon cable of a construction work, the cable layer comprising at least a first guy and a second guy, characterized in that the device comprises at least one damper with a substantially linear stroke which has a first articulated connection on the first stay and a second articulated connection on the second stay, and in that the axis of the damper is substantially perpendicular to the first and second stay of such so that its damping stroke is substantially perpendicular to the first and second shrouds.
• a damper as defined above can therefore be directly disposed on the middle portions of two adjacent guy lines at which the amplitude of vibration is highest.
• the damper with a substantially linear stroke comprises a piston body and a piston mounted to move relative to the piston body, said piston body being provided with the first articulated connection , and the piston being provided with the second articulated connection;
• the first and second connections each comprise a collar attached around the shroud which is associated with it, and a pivot connection which connects the collar to the shock absorber;
• the pivot link is a pivot link perpendicular to the longitudinal direction of the corresponding stay and to the plane containing the first and second stay;
• each collar is mounted tight around the shroud associated with it; each collar is pivotally attached around a support mounted tight on the shroud which is associated with it;
• Each collar is attached pivoting around the support with a predetermined coefficient of friction so as to allow damping in rotation of each collar around the support during movements of the corresponding shroud in a direction perpendicular to the plane containing the first and second shroud
• the invention also relates to a method of damping the vibrations of a sheet of shrouds of a construction work, characterized in that the damping of vibrations is carried out by means of a device as defined above.
• FIG. 1 shows a construction work such as a cable-stayed bridge provided with a plurality of devices for damping the vibrations of a shroud layer
• - Figure 2 shows a device according to the invention to dampen the vibrations of two adjacent shrouds of the same shroud ply
• - Figure 3 shows an enlarged view of the articulated connections of two shock absorbers attached to the same shroud
• Figure 4 shows a longitudinal sectional view of a portion d 'a stay intended to receive at least one articulated connection of a shock absorber
• FIG. 5 represents a cross-section view of the portion of the stay intended to receive at least one articulated connection of a shock absorber
• FIG. 5 represents a cross-section view of the portion of the stay intended to receive at least one articulated connection of a shock absorber
• FIG. 6 represents a view side view of the portion of the device shown in FIG. 3, when the shroud does not undergo any transverse displacement
• - FIG. 7 represents a side view of the portion of the device rep resentée in Figure 3, when the shroud undergoes a transverse movement
• - Figure 8 shows an alternative embodiment of the connection of one end of a damper on a shroud.
• FIG. 1 represents a construction work which is in the form of a cable-stayed bridge 1 which comprises at least one pylon 2, an apron 3 and in the example considered here two plies of stay cables 4 and 5 which connect the apron 3 to the pylon 2.
• the guy plies 4 and 5 are used to support the part of the deck 3 which does not rest on support pylons (part of the deck located to the right of the pylon 2 in the example considered here).
• the shroud ply 4 is formed by a set of shrouds which are inclined downward and to the right, each shroud having an upper end anchored in a respective anchoring zone arranged on the pylon 2 and a lower end anchored on the deck 3.
• the shroud ply 5 comprises a set of shrouds inclined downwards and to the left, each shroud of this shroud ply 5 having an upper end directly anchored in a respective anchoring zone arranged on the pylon 2, and a lower end anchored on the deck 3.
• each stay is formed by a bundle of metal strands 41 which are anchored at their two ends, and a plastic sheath 42 which surrounds and protects the bundle of metal strands 41 from the outside and in particular from corrosion.
• This sheath 42 can for example be made from high density polyethylene (HDPE).
• FIG. 2 represents a detailed view of a portion of the ply of stay cables 4, and more particularly of a first stay 4a and a second stay 4b which are connected together by a damping link 6 according to the invention.
• This damping link 6 is in the form of a damper 6 having a substantially linear stroke and which comprises a first link 7 articulated on the first guy 4a and a second link 8 articulated on the second guy 4b directly adjacent to the first guy 4a.
• This damper 6 can be of the viscous damper type, in particular a hydraulic piston damper, or of the friction damper type comprising a piston intended to move with friction relative to a piston body.
• piston damper 6 which comprises, on the one hand, a piston body 61 which is extended, in the direction of the first shroud 4a, by a metal tube 62 which is itself provided with the first connection 7, and on the other hand, a piston 63 intended to move inside the piston body 61 in a linear stroke, this piston 63 being provided with the second connection 8.
• the piston damper 6 used to dampen the vibrations of two adjacent shrouds can in particular be similar to those used for trucks or trains, this shock absorber being able to be extended by metal bars or tubes themselves provided with articulated connections 7 and 8.
• the piston dampers 6 do not have a permanent normal force, the piston 63 adjusting to the distance at rest between the first and second shrouds 4a, 4b without exerting any effort.
• This characteristic of the piston dampers 6 is advantageous compared to the interconnection cables which deflect the shrouds downwards due to their pre-loading, thus reducing the effectiveness of the shrouds, which often requires adding strands or strands. additional in these shrouds.
• the piston damper 6 unlike a conventional interconnection cable, is capable of transmitting tensile, compression, but also bending forces.
• the first and second shrouds 4a, 4b can also be connected to the shrouds which are directly adjacent to them by means of piston dampers 6 strictly identical to that which connects said first and second shrouds 4a, 4b.
• each piston damper 6 will be provided with a first link 7 or lower link 7 directly articulated on the stay which is lower than it as well as with a second link 8 or upper link directly articulated on the stay which is higher than it. .
• each piston damper 6 is arranged substantially perpendicular to the two shrouds it connects.
• each piston damper 6 forms an angle of 90 ° with the two shrouds in order to avoid introducing longitudinal forces, that is to say in the axis of the shrouds, in the first and second links 7, 8 which could cause them to slide along the shrouds.
• each damper 6 is arranged perpendicular to the bisector of the angle formed by the two shrouds that it connects. Consequently, when several piston dampers 6 are arranged one after the other on several stay cables, as shown in FIG. 1, the elevation plot of the piston dampers has a substantially curvilinear shape.
• the first link 7 of each piston damper 6 comprises a steel collar 9 attached around the shroud which is associated with it, as well as a pivot link 10 which connects the collar 9 to the pivot damper 6 or more particularly to the metal tube 62 directly connected to the piston body 61 of said piston damper 6.
• the pivot link 10 is in the form of a female yoke comprising two flanges 10a which are extend upwards from the collar 9 and in which are respectively provided two holes which are arranged opposite and along an axis perpendicular to the axis of the shroud.
• the metal tube 62 of the piston damper 6, for its part, has one end in the form of a male yoke 11 disposed between the two flanges 10a of the female yoke, the male yoke 11 also comprising a hole arranged in correspondence mutual with the holes of the female yoke.
• the male and female yokes are connected together by means of a pin 12 which extends perpendicular to the axis of the stay.
• the collar 9 is, in the example considered here, in the form of two parallel flanges 91 provided with circular openings which directly surround the shroud.
• the guy is provided with a metal tube 13 on which is intended to be attached the collar 9.
• the sheath 42 is cut, and two sections 42a made from HDPE are fixed respectively to the two cut ends of the sheath 42.
• These two sections 42a which each have a thickness greater than the thickness of the sheath 42, are each provided with an external thread intended to cooperate by screwing with an internal thread produced on the metal tube 13.
• a shim 14 is also directly related to the inside of the sheath 42 prior to the screwing of the metal tube 13 on the two sections 42a.
• This wedge 14 has the function of clamping the metal strands 41 against the two sections 42a with minimum clearance. After fitting this wedge 14, the metal tube 13 is screwed and then permanently fixed, for example by welding, on the two sections 42a. The collar 9 or more exactly its two flanges 91 can then be attached to the metal tube 13. When the collar 9 is attached to the metal tube 13 before the commissioning of the structure, the flanges 91 can be fitted by the one of the ends of the corresponding shroud then translate to the metal tube 13.
• each flange 91 can be formed by a first semi-cylindrical half-flange made in one piece with the pivot 10 and by a second semi-cylindrical flange. These two half-flanges will then be arranged around the metal tube 13 and then fixed to one another, for example by screwing, to form the collar 9.
• the two flanges 91 of the collar 9 are then blocked in translation on the metal tube 13 by means of two stops 13a disposed on either side of the two flanges 91, these stops being able to be attached and directly welded to the cylindrical tube 13.
• each piston damper 6 also includes a collar 15 made of steel attached around the shroud associated with it, as well as a pivot link 16 which connects the collar 15 to the pivot shock absorber 6.
• the pivot connection 16 is also in the form of a female yoke comprising two flanges 16a which extend downwards from the collar 15 and in which are provided respectively two holes which are arranged opposite and along an axis perpendicular to the axis of the shroud.
• the piston 63 of the pivot shock absorber 6 has an end in the form of a male yoke 17 disposed between the two flanges 16a of the female yoke, the male yoke 17 also having a hole arranged in correspondence with the holes in the female yoke.
• the collar 15 is in the form of a single flange disposed between the two flanges 91 of the collar 9.
• This flange 15 comprises a circular opening which directly surrounds the shroud or more exactly the cylindrical tube 13.
• the collar 5 can be formed in one piece or in two pieces as described above for the collar 9.
• the collars 9 and 15 of the first and second connections 7 and 8 therefore completely surround the shrouds to which they are attached while being connected to a piston damper 6 by means of a pivot connection 10 or 16 having a pivot axis only perpendicular to 1 ′ axis of the shroud and to the plane containing the shrouds.
• a pivot connection 10 or 16 having a pivot axis only perpendicular to 1 ′ axis of the shroud and to the plane containing the shrouds.
• the force exerted by each piston damper is applied via the collar 9 or 15 to the cylindrical tube 13, at the center thereof, that is to say at the center of gravity of the cross section the corresponding shroud, thus avoiding any risk geometric instability which could lead to the twisting of at least one of the shrouds.
• the metal tube 13 must be able to withstand the shearing forces which appear between the collar 9 and the collar 15.
• the collars 9 and 15 can be directly fixed around the metal tube 13 without any degree of freedom in rotation around said metal tube.
• the collars 9 and 15 can be pivotally mounted with a minimum of friction around the metal tube 13 by means of an appropriate lubricant, as shown in FIGS. 6 and 7.
• each of the first and second link 7.8 is formed by a pivot link 10.16 perpendicular to the axis of the corresponding shroud and by another pivot link, formed by the tube 13 and each collar, which is centered and parallel to the axis of the shroud corresponding
• the first and second connections 7 and 8 therefore each form connections with two pivots with two degrees of freedom similar to ball joints without however have the disadvantages of ball joints which in this case would cause geometric instability related to the fact that the force exerted by each piston damper would be more applied to the center of gravity of the cross section of the corresponding shroud
• the collars 9 and 15 first and second links 7 and 8 are pivotally attached to the metal tube 13 with a predetermined coefficient of friction to allow damping in rotation of the transverse movements
• the internal walls of the circular openings of the collars 9 and 15 as well as the external wall of the metal tube 13 can be adapted to present a friction surface whose effort is controlled by an appropriate choice of materials.
• the presence of an appropriate friction lining directly interposed between the collars 9, 15 and the metal tube 3 can also make it possible, by damping in rotation, to limit the transverse movements of the shrouds.
• the materials in contact must have durable anti-wear properties, such as metaloplast and guarantee a constant coefficient of friction over time.
• Figure 8 shows an alternative embodiment of the pivot connection between the metal tube 13 and the collar 15 to limit the transverse vibrations of the shrouds by damping in rotation between the collar 15 and the tube 13 integral with the shroud.
• This collar 15, pivotally mounted on the metal tube 13, is in the form of an open collar comprising two free ends 15a, 15b which are interconnected by means of an adjustable clamping system 19.
• This adjustable clamping system 19 can for example be in the form of a spring system, Belleville washer, or a jack acting to bring the ends 15a, 15b towards each other so as to control the tightening of said collar 15 against the metal tube 13.
• the tightening adjustment makes it possible to modify the coefficient of friction between the internal surface of the collar 15 and the external surface of the cylindrical tube 13, thereby modifying the damping transverse of the shroud or of the plurality of shrouds which will be interconnected by means of piston dampers 6.
• this embodiment of the collar 15 can also be applied to the flanges 91 of the collar 9.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Bridges Or Land Bridges (AREA)
• Fluid-Damping Devices (AREA)
• Vibration Prevention Devices (AREA)
• Buildings Adapted To Withstand Abnormal External Influences (AREA)

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Applications Claiming Priority (2)

Publications (1)

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ID=34508408

Family Applications (1)

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Cited By (4)

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Citations (5)

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• 2003
  • 2003-11-12 FR FR0313240A patent/FR2862073B1/fr not_active Expired - Fee Related
• 2004
  • 2004-03-30 JP JP2004098535A patent/JP4504716B2/ja not_active Expired - Fee Related
  • 2004-11-08 MY MYPI20044636A patent/MY141276A/en unknown
  • 2004-11-09 US US10/578,818 patent/US7631384B2/en not_active Expired - Fee Related
  • 2004-11-09 WO PCT/FR2004/002880 patent/WO2005049923A1/fr not_active Ceased

Patent Citations (5)

Non-Patent Citations (3)

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