EP1031680A1 - Articulated paraseismic elastoplastic device for civil engineering construction and bridge with such a device - Google Patents

Abstract

Longitudinal shock absorbers (13, 13') are placed between deck (1) and leg of pylon (7). Shock absorber comprises beam (14) and knuckle-jointed connecting rod (15). Beam can rotate relative to connecting rod, around axis (16), slightly perpendicular to plan T. Extreme inner beam section (17) is placed in arching template (18), firmly attached to outer lateral edge (19) of deck. An Independent claim is also included for the description of the suspension bridge.

Description

The invention relates to a device for limiting the amplitude of the relative displacement of two structural elements of civil engineering placed in screw when this structure is subjected to intense stress mechanical.

This mechanical stress can be linked, for example, directly or indirectly to seismic waves or meteorological phenomena such as hurricanes, storms, tornadoes.

The invention relates more specifically but not exclusively to cable-stayed bridges, the device according to the invention being able to be easily installed place during bridge construction or when reinforcing a bridge former.

The device according to the invention, when it is installed for a bridge such as a cable-stayed bridge also makes it possible to limit displacements due to wind and ensure proper functioning of the road joints located at ends of the work.

Earthquakes are the source of large-scale disasters, particularly particularly in highly urbanized areas.

The Tangshan earthquake in China in 1976 alone claimed 800,000 victims.

More recently, the Kobe earthquake in Japan in 1995 reportedly has 5,000 victims and that of Mexico City, in 1985, 20,000 dead, many of them following the collapse of buildings.

It is estimated that in the 20th century, more than 1,700,000 people died during earthquakes, very often due to the collapse of residential buildings or civil engineering structure in general.

Regardless of the Richter scale used to assess scientifically the total energy of an earthquake, the macroscopic scale MSI also largely correlates the amplitude of earthquakes to the destruction of buildings.

Regulations have gradually been put in place across the world, establishing rules for earthquake-resistant constructions, in particular for high-rise buildings and establishments receiving the public.

France, although rarely subject to major earthquakes, has also implemented earthquake regulations in 1955, several times subsequently modified.

Most European countries also have regulations in this area.

In addition to these legislative developments, earthquake-resistant construction has experienced significant technical developments.

Various types of seismic devices have been designed.

• les amortisseurs tels que des vérins et d'une manière générale les dispositifs tirant profit des propriétés rhéologiques des fluides amortissant, plus ou moins visqueux ;
• les dispositifs incluant des pièces mécaniques de type fragiles, telles des butées fusibles qui modifient la réponse d'une structure donnée lors d'un séisme ;
• les dispositifs dissipant l'énergie mécanique des vibrations sismiques par frottement.

We can distinguish in particular:

• dampers such as cylinders and generally devices taking advantage of the rheological properties of damping fluids, more or less viscous;
• devices including mechanical parts of the fragile type, such as fusible stops which modify the response of a given structure during an earthquake;
• devices dissipating mechanical energy from seismic vibrations by friction.

• demandes de brevet en France N° : 2 698 400, 2 643 105, 2 625 763, 2 602 293, 2 594 193, 2 694 400, 2 594 193 ;
• demandes de brevet européen N° : 411 876, 443 988, 366 627 , 56 258;
• demande internationale de brevet N° 95 14 830 ;
• brevets américains N°: 5 347 771, 5 311 709, 5 339 580 , 5 487 534, 5 201 155, 5 447 001, 5 147 018, 5 103 605, 5 074 086, 5 174 082, 4 991 366, 5 182 888, 4 953 330, 5 005 326, 4 917 211, 4 910 930, 4 910 929, 5 373 670, 4 950 628, 4 761 925, 4 830 927, 4 731 966, 4 605 106, 4 593 501, 4 651 481, 4 599 834, 4 269 011.

Examples of earthquake-resistant devices such as those listed above can be found in the following documents:

• patent applications in France N °: 2,698,400, 2,643,105, 2,625,763, 2,602,293, 2,594,193, 2,694,400, 2,594,193;
• European patent applications No: 411 876, 443 988, 366 627, 56 258;
• international patent application No. 95 14 830;
• U.S. Patent Nos. 5,347,771, 5,311,709, 5,339,580, 5,487,534, 5,201,155, 5,447,001, 5,147,018, 5,103,605, 5,074,086, 5,174,082, 4,991,366.5 182 888, 4 953 330, 5 005 326, 4 917 211, 4 910 930, 4 910 929, 5 373 670, 4 950 628, 4 761 925, 4 830 927, 4 731 966, 4 605 106, 4 593 501 , 4,651,481, 4,599,834, 4,269,011.

There are also earthquake-resistant devices in which part of mechanical energy, resulting from the stress to which the civil engineering structure, is absorbed by plastic deformation of a part of the device provided for this purpose.

Document US-A-3,963,099 describes an earthquake-effect device hysteresis. A beam is rigidly fixed to the foundations, elements of guide in contact with the beam before its deformation being deformed with beam. This beam can be of cylindrical or prismatic section with three or more than three sides. There are as many guide bars as there are faces beam. The guide bars are 0.5 to 1 times the thickness of the beam and are about 33% high of the total height of this beam. A cylindrical head is attached to the upper end of the beam, this head being placed in a cylinder fixed to the building. The maximum rotation of the beam is around 15 °.

Reference may also be made to the following documents: US-A-5,452,549, WO-A-96 27 055, WO-A- 94 28 332, US-A- 5 163 256, US-A- 5 065 555, US-A- 4,901,486, EP-A 477,144, WO-A- 95 14,830, EP-A- 443,988, US-A- 5,452 549, EP-A- 366 627, EP-A- 206 183.

Energy dissipating means by plastic deformation for earthquake-resistant constructions known from the prior art have important disadvantages.

Despite the care taken in defining their geometry, the parts plastically deformable can deform uncontrollably, when placed in such complex stress fields than those related to earthquakes.

A location of deformation of these parts is possible, the energy absorbed by plastic deformation then being very reduced.

Similarly, an early rupture, on a defect in the material forming the parts deformable is possible.

Document FR-A-2 756 581, from the applicant, describes a device earthquake-proof to solve the technical problems mentioned above above.

The seismic device described in this document FR-A-2 756 581 includes means for guiding the plastic deformation of means deformable such as a beam connecting two parts of an engineering structure civilian likely to move relative to each other during earthquakes.

The invention relates to a seismic device comprising means plastically deformable in a controlled manner, these means having inertias and geometries adapted to both mechanical stresses exceptional events such as those encountered during earthquakes more common stresses such as those related to wind.

The invention relates more particularly but not exclusively to bridges guyed.

It is stated here, for the sake of clarity, that the term "guy" which will be used in the rest of the text relates to a conventionally metallic cable, inclined and straight, possibly sheathed, contributing to the stability of a work of great height or supporting the deck of a cable-stayed bridge or guyed bridge, the guy wires being fixed to pylons.

The shrouds can be arranged parallel to each other (guying in harp) or radiating from the head of the pylons (fan stays).

The shrouds can form a central ply or two lateral plies.

Cable-stayed bridges are tall structures with only a small number of support points, namely the pylons and some additional piers.

The general structure of cable-stayed bridges is a priori mechanically unfavorable for earthquake resistance, pylons with moments of large spillage and bending.

In order to mitigate this disadvantage, it can be considered advisable to completely suspend the deck of the cable-stayed bridge, without any connection vertical at the level of the pylons.

Then, the apron will be able to oscillate in the event of earthquakes like a swing whose the movements are disconnected from the supporting structure or in any case at completely different natural frequencies.

The device according to the invention makes it possible to limit these oscillations all in ensuring proper functioning of the road joints at the ends of the structure and traffic safety, including in the event of strong winds.

• la figure 1 est une vue en élévation d'un pont à haubans comprenant au moins un dispositif selon l'invention ;
• la figure 2 est une vue en élévation d'un pylône du pont représenté en figure 1, selon un mode de réalisation de l'invention ;
• la figure 3 est une vue de détail d'une partie des amortisseurs représentés en figure 2 ;
• la figure 4 est une vue en coupe transversale selon le plan IV-IV de la figure 3 ;
• la figure 5 est une vue en coupe transversale selon le plan V-V de la figure 3 ;
• la figure 6 est une vue de détail des amortisseurs représentes en figure 4 ;
• la figure 7 est une vue en coupe selon le plan VII-VII de la figure 6 ;
• la figure 8 est une vue de détail d'amortisseurs transversaux selon un deuxième mode de réalisation de l'invention ;
• la figure 9 est une vue en coupe selon le plan IX-IX de la figure 8, la figure 8 étant une vue selon le plan VIII-VIII de la figure 9 ;
• la figure 10 est une vue de détail d'amortisseurs longitudinaux selon un deuxième mode de réalisation de l'invention ;
• la figure 11 est une vue de détail d'amortisseurs selon un troisième mode de réalisation de l'invention ;
• la figure 12 est une vue selon le plan XII-XII de la figure 11 ;
• la figure 13 est une vue selon le plan XIII-XIII de la figure 11.

Other objects and advantages of the invention will appear during the following description of embodiments, which description will be made with reference to the accompanying drawings, among which:

• Figure 1 is an elevational view of a cable-stayed bridge comprising at least one device according to the invention;
• Figure 2 is an elevational view of a pylon of the bridge shown in Figure 1, according to an embodiment of the invention;
• Figure 3 is a detail view of part of the shock absorbers shown in Figure 2;
• Figure 4 is a cross-sectional view along the plane IV-IV of Figure 3;
• Figure 5 is a cross-sectional view along the plane VV of Figure 3;
• Figure 6 is a detail view of the shock absorbers shown in Figure 4;
• Figure 7 is a sectional view along the plane VII-VII of Figure 6;
• Figure 8 is a detail view of transverse dampers according to a second embodiment of the invention;
• Figure 9 is a sectional view along the plane IX-IX of Figure 8, Figure 8 being a view along the plane VIII-VIII of Figure 9;
• Figure 10 is a detail view of longitudinal dampers according to a second embodiment of the invention;
• Figure 11 is a detail view of shock absorbers according to a third embodiment of the invention;
• Figure 12 is a view along the plane XII-XII of Figure 11;
• FIG. 13 is a view along the plane XIII-XIII of FIG. 11.

We first refer to Figure 1.

Figure 1 is an elevational view of a cable-stayed cable bridge.

It is understood here that the invention is in no way limited to the field special technique of cable-stayed or suspended cable bridges, but can be used in any type of bridge and in general in any type of civil engineering structure in which two elements of structure are likely to be moving relative to each other under the effect of seismic waves and / or more usual stresses such as those related to the wind for example.

The cable-stayed and suspension bridges have been known per se long time.

Multiple guy lines appeared in 1967 and were to become essential thereafter, the French Brotonne bridge over the Seine, built by the plaintiff in 1975, with a range of 320m having remained a model of the genre for a long time.

• 1996 : pont de Normandie, 2141 m de longueur totale, 856 m de portée centrale ;
• 1998 : Tatara bridge, 890 m de portée pour la travée centrale.

Since then, the spans and the total lengths of the cable-stayed bridges have not stopped growing:

• 1996: Normandy bridge, 2141 m total length, 856 m central span;
• 1998: Tatara bridge, 890 m span for the central span.

The heights of the pylons also increased, exceeding 200 m today, for a weight of more than 20,000 tonnes per pylon.

FIG. 1 represents an elevation view of a symmetrical cable-stayed bridge with three spans, therefore comprising two pylons.

It is understood here that the invention could be applied to cable-stayed bridges at single pylon or bridges with multiple guyed spans.

The deck 1 of the bridge can be metallic or prestressed concrete, with a box of constant height or not, with full or open slab.

The apron can, in other embodiments, be mixed and include metal boxes and a reinforced concrete slab, the boxes having a section for example trapezoidal.

The edge spans 2,3 do not rest on intermediate piers but may include pills, the shrouds 4 fixed on these pills playing the role of retaining shrouds.

The shrouds 4 can be made from cables with parallel wires, cables formed by parallel strands or closed cables.

By “cables with parallel wires”, conventionally is meant sets of wires drawn in high strength steels, placed in polyethylene or metal tubes, wax, grease or grout cement filling the empty space between the wires, after tensioning.

By "closed cables", conventionally means bundles of wires circular section parallel surrounded by section wire rings trapezoidal and Z-shaped wires.

The strands can be of the type used in prestressing.

The shrouds can be stretched between two points of the apron located on the side and on the other side of a pylon or between a point on the deck and a point on the pylon.

In the first case, rigid metal tubes constituting saddles support are then provided in the upper area of the pylons when the guy wires are arranged in a semi-fan shape and cross the pylons.

In the second case, rigid tubes and anchor blocks are placed in head of the pylons, as in some not shown realizations.

In the embodiment of FIG. 1, the shrouds 4 are in harp and secondary cables, called “needles” 4 'connect the shrouds together so as in particular to limit the risks of resonant vibrations of the guy lines under the effect of the wind.

The suspension of the apron can be lateral, i.e. the apron can be supported by two side cable stays, the pylons 5 comprising two masts.

In other embodiments, such as that shown, the suspension of the deck can be axial, the pylons having an A shape surmounted by a shaft vertical, for example.

As it appears in FIG. 2, the pylons, in the embodiment shown, include two inclined legs 6,7 joined by a vertical shaft in part superior.

The masts 6.7 have a basal portion 9.10 below a spacer 11, this basal portion 9.10 being inclined at an angle α of the order of 5 to 30 ° approximately with respect to the vertical, the two basal parts converging one towards the others at their lower end.

In other embodiments, not shown, the pylons have substantially H-shaped, the shrouds being arranged in two layers lateral, the basal parts located below the spacer being inclined with respect to the vertical, by an angle of about 5 to 20 ° approximately and diverging from each other at their lower end.

The top parts 11,12 of the legs 6,7, above the spacer 8, are inclined by an angle β relative to the vertical, this angle β being substantially equal to the angle α defined previously, in the embodiment represented.

The pylons have a substantially vertical plane of symmetry S, in the illustrated embodiment.

In the remainder of the text the term "longitudinal" will be used with reference to the direction D1 contained in a plane T perpendicular to the plane of symmetry S, this direction D1 corresponding to the largest dimension of the deck 1.

In the embodiment shown, this direction D1 is substantially horizontal.

In other embodiments, not shown, the deck includes a curved profile whose ends are at the same level or at least a part curved and / or at least a part with a straight but inclined profile.

In the rest of the text, the term “transverse” will be used with reference to the direction D2 contained in the plane T defined above, the direction D2 being substantially perpendicular to direction D1.

The terms "external", "exterior", "internal", "interior", "lower", "Superior", will be used subsequently with reference to a point P of the apron 1 placed between the legs 6,7 of a pylon 5 and halfway between them.

The pylons 5 are provided with seismic devices of the elastoplastic type with controlled deformation, further enabling blocking or limiting the movements of the deck 1 under the effect of the wind or other stresses in service.

We first describe a first embodiment of these devices earthquake resistant, with reference to Figures 2 to 7.

At least one longitudinal damper 13 is disposed between the deck 1 and at minus one leg 6.7 of a pylon 5.

This longitudinal damper 13 comprises a beam 14 and a connecting rod articulated 15.

The beam 14 is articulated in rotation, relative to the connecting rod 15, around a axis 16, substantially perpendicular to the plane T.

The inner end portion 17 of the beam 14 is placed in a template bending 18, secured to the external lateral edge 19 of the deck 1.

In the plane of Figure 4, parallel to the plane T, the beam 14 extends at least before deformation of the shock absorber - and therefore in particular during its implementation place - substantially in direction D2 and the connecting rod 15 extends substantially in direction D1.

The connecting rod 15 is articulated in rotation, relative to the mast 7 of the pylon 5, around an axis 20 substantially parallel to the axis 16.

The axis 20 is linked to the part 21 secured to the mast 7.

The connecting rod 15 can be provided as shown with a hydraulic coupler or mechanical 22.

In one embodiment, this coupler 22 only deforms when the applied stress exceeds a threshold value.

In a particular embodiment, this coupler has a viscous behavior and high sensitivity to the speed of deformation, a low strain rate leading for example to a strain immediate, for example to take account of the movements of the deck 1 under the effect of thermal expansion or creep, a speed of high deformation leading to blockage of the coupler and / or dissipation of mechanical energy by friction, at least for a certain range of constraints.

The bending jig 18 includes two bending surfaces 23,24 substantially symmetrical with respect to a median plane of the beam 14, in the embodiment shown.

In other embodiments, not shown, the template does not include that a curved surface guiding the plastic deformation of the beam 14.

In still other embodiments, the template includes two curved surfaces whose radii of curvature and / or dimensions are not not identical.

In the embodiment shown in Figure 4, the bending surfaces 23.24 have a substantially constant radius of curvature over their entire length.

The bending template 18 thus has an opening 25 of section rectangular going regularly flaring from the inside to the outside.

This opening 25 can, if necessary be filled with a soft product, not not resistant to compression but protecting the beam 14, housed in the template 18, against atmospheric attack.

The beam 14 can be made of metallic material, provided the case protection against corrosion.

The beam 14 having to deform plastically when the shock absorber is highly stressed, for example in the event of an earthquake, the material used to elaboration must exhibit non-fragile behavior, the level of ductility of this material and its plasticity threshold being chosen as a function of the amount of mechanical energy that one wishes to absorb.

The beam 14 can be produced by assembling different materials.

The beam 14 may have a profile with variable inertia so as to allow simultaneous laminating of all sections of the profile and so allow efficient dissipation of mechanical energy.

The vertical section of the beam can thus be of decreasing dimension regularly from the inner end of this beam to its opposite extreme part.

As it appears in Figure 7, the beam 14 can be formed by assembly of metal plates 14a, 14b, 14c, 14d, 14e.

Two longitudinal dampers 13 can be put in place, for each pylon leg, if applicable on either side of each leg as well that it is represented in FIG. 4.

The two shock absorbers 13, 13 ′ may be identical in structure and dimensions or not.

So, for example, and depending on the expected stress fields, the shock absorber 13 ′ may be devoid of a hydraulic or mechanical coupler 22.

In the embodiment shown in Figure 4, the dampers 13,13 'are arranged symmetrically with respect to a median plane P of the leg 7 of a pylon 5.

In other embodiments, not shown, the damper 13 'is placed at above or below the damper 13 and / or the hinge pin 16 'of the connecting rod 15 ′ with respect to the beam 14 ′ is arranged more outside or more inside as the corresponding axis 14 of the shock absorber 13.

We now refer to Figure 5.

In addition to at least one longitudinal damper as described above, at less a transverse damper 26 can be placed between a leg of a pylon and apron.

In the embodiment shown in FIG. 5, the transverse damper 26 comprises a beam 27 and a connecting rod 28, the connecting rod 28 being mounted articulated in rotation about an axis 29 relative to the beam 27.

The end part 30 of the beam 27 opposite the articulation 29 is placed in a bending jig 31 fixed to a side wall of the leg 7, the template 31 comprising two guide surfaces 32, 33 of the deformation beam plastic 27.

Bending surfaces 32.33 have a radius of curvature substantially constant over their entire length and are symmetrical with respect to to a median plane P 'of the beam 27.

So that the template 30 defines an opening 34 of rectangular section going in flaring going towards the axis of articulation 29.

In other embodiments, not shown, the surfaces of bending are not symmetrical to each other with respect to the plane P 'and / or do not have a constant radius of curvature along their length.

If necessary, the template 31 may contain a soft product, not resistant under compression but protecting the beam 27 housed in the template 30 against atmospheric aggressions.

The beam 27 can be made of metallic material, provided where appropriate corrosion protection.

The beam 27 must be able to deform plastically when the shock absorber is highly stressed, for example during earthquakes, the material used for its elaboration must exhibit non-fragile behavior, the level of ductility of this material and its plasticity threshold being chosen as a function of the amount of mechanical energy that one wishes to absorb.

The beam 27 can be made from different materials.

The beam 27 may have a profile with variable inertia, so as to allow the plasticization of all sections of the profile and thus allow a efficient dissipation of mechanical energy.

The beam 27 can be produced by assembling metal plates 27a, 27b, 27c, 27d, 27e, analogously to what was mentioned above for beam 14.

The connecting rod 28 is articulated in rotation about an axis 35 relative to the deck 1, a part 36 defining the axis 35 and being mounted integral on a wall side 19 of deck 1.

As shown in FIG. 5, two shock absorbers 26, 26 'can be provided on at least one leg of a pylon 5.

These transverse dampers can be of structure and dimensions identical or not.

In the embodiment shown, the dampers 26, 26 'are placed in symmetry with respect to the plane P defined previously.

The beams 27, 27 ′ are, at least when the shock absorbers are in place, substantially aligned in a direction parallel to D1.

The connecting rods 28, 28 'are in turn, at least during the installation of the shock absorbers, substantially parallel to the direction D2.

As it appears in Figure 3, the hinge pin 16 of the rod 15 of a longitudinal damper is placed farther outside than the articulation axis of the connecting rod 28 of the transverse damper 26 placed opposite.

In other embodiments, not shown, the axes of articulation 16, 29 of the connecting rods 15, 28 are substantially aligned.

In still other embodiments, not shown, the axis 29 is placed further inside than axis 16.

The longitudinal damper (s) 15, associated with a mast considered, can be placed above or below the shock absorber (s) transverse 26.

In the embodiment shown in Figure 3, the shock absorbers longitudinal are placed above and parallel to the shock absorbers transverse.

If necessary, several longitudinal dampers and / or several transverse dampers can be placed parallel to the T plane and in look at each other for at least one pylon.

We now refer to Figures 8 to 10 which illustrate a second embodiment of shock absorbers according to the invention.

In Figures 8 and 9 is shown a transverse or longitudinal damper along the orientation with respect to directions D1 and D2 of the beam 37 plastically deformable.

The lower end portion 38 of the beam 37 is placed in a housing 39 of the spacer 11 of a pylon 5.

The upper end portion 40 of the beam 37 is mounted articulated around an axis 41 relative to a piece 42 sliding in a housing 43 of the apron 1.

It is understood that the spacer and the apron could be elements of a civil engineering structure, the structure of the shock absorber being identical to that shown.

The housing 39 includes wedging means 44 of the end part bottom 38 of beam 37.

In the upper part, the housing 39 includes a deformation template 45.

In certain embodiments, this template 45 comprises at least two deformation guide surfaces, substantially symmetrical with respect to to a median plane P "on beam 37, of radii of constant curvature on their length or not.

The opening of the template 45 is then of rectangular or square section, the template flaring regularly towards the apron 1.

In other embodiments the template 45 is substantially cylindrical and flares towards the apron 1 in the manner of a trumpet mouth.

The opening of the template may contain a soft product, not resistant to compression but protecting beam 37 from atmospheric aggressions.

The beam 37 is, in the embodiment shown, formed by a assembly of parallel plates 37a to 37g, these plates being bolted and / or welded together by any suitable process known per se.

Where appropriate, as shown, struts 46, 47 are mounted articulated at their first end part 48 to the spacer 11 and are integral, at their opposite end to the beam 37, are directly either by through a room surrounding the beam 37.

The term bracon is used here to the extent that it denotes conventional a short support piece arranged obliquely, the pieces 46.47 arranged obliquely to the beam 37 having the function of support it and participate in guiding its deformation.

Sliding plates 49 can be provided between the side walls ends of the part 42 and the housing 43 of the deck 1.

These plates 49 can be in two parts, one made of polytetrafluoroethylene PTFE integral with the slide 42, the other in stainless steel integral with the housing 43.

Other materials which may have undergone a surface treatment can be envisaged, as is known, to obtain coefficients of low friction between the walls of the housing 43 and the slide 42 bearing the axis 41 of rotation of the beam 37.

The device shown in Figures 8 and 9 can be arranged vertically or in any other direction.

Several devices of the type shown in Figures 8 and 9 can be implemented place during the construction of a civil engineering structure such as a bridge shrouds for example, or when consolidating an old structure.

If necessary, the beams 37 of each shock absorber can be arranged to be deformable in different directions, for example longitudinal, transverse and oblique example.

In the embodiment shown in Figure 10, a longitudinal damper in the example considered, comprises a beam 50 which can be similar with the beams 14.37 described above, is placed in a template of bending 51 which can be analogous to the bending jigs 18, 31, 45 described previously.

The beam 50 is articulated in rotation to a connecting rod 52, around an axis 53.

The connecting rod 52 is itself articulated to a hydraulic or mechanical coupler, of the type described above, this coupler 54 being integral with the deck 1.

In the embodiment of Figures 8 to 10, the damper works as a console, the articulated rod of the longitudinal damper ensuring the transmission of forces between the deck and the pylon.

We now refer to Figures 11 to 13 which illustrate a third embodiment of the invention.

In this third embodiment, two shock absorbers 55, 56 provided each of a plastically deformable beam 57, 58 are placed between the spacer 11 and the deck 1 of the bridge.

It is understood here again that the deck 1 and the spacer 11 could be two any parts of a civil engineering structure, likely to be move relative to each other under the effect for example of constraints linked to earthquakes.

Each beam 57, 58 can be plastically deformed on jigs of deformation 59, 60, 61, 62.

More specifically, the beam 58 of the longitudinal damper 56 is guided in its possible plastic deformation by two curved surfaces 63, 64 to simple radius of curvature substantially constant.

These curved surfaces 63, 64 are substantially symmetrical with respect to a median plane to beam 58, in the embodiment shown.

In other embodiments, not shown, the surfaces 63, 64 do not are not symmetrical to each other and / or have a radius of curvature variable from one edge 65 to the other edge 66.

The two ends of the beam 58 are articulated in rotation around axes 67, 68 substantially parallel, with respect to two connecting rods 69, 70 respectively.

The connecting rod 69 is itself articulated in rotation about an axis 71 relative to to a hydraulic or mechanical coupler 72, of the type analogous to those defined above.

Similarly, the connecting rod 70 is articulated in rotation about an axis 73 relative to to a hydraulic or mechanical coupler 74.

When installing the shock absorber 56 for operation in longitudinal mode, the beam 58 is substantially placed in the direction D2 and the connecting rods 70, 71 are substantially parallel to the direction D1.

The articulation axes 67, 68, 71 and 73 are then substantially parallel between them and perpendicular to the plane T.

The beam 57 of the shock absorber 55 is originally placed in the direction D1, the damper 55 then being transverse.

This beam 57 is guided in its possible plastic deformation by two guide templates 59, 60 comprising two single guide surfaces substantially constant curvature 75, 76, symmetrical with respect to a plane median to beam 57, in the embodiment shown.

The beam 57 is articulated in rotation about axes 77, 78 with respect to two connecting rods 79, 80 respectively.

These connecting rods 79, 80 are themselves articulated in rotation about axes 81, 82 defined by parts supporting axes 83, 84 integral with the deck 1.

When the damper 55 is put in place, the beam 57 is substantially arranged in the direction D1 and the connecting rods 79, 80 are substantially parallel to direction D2.

The axes 77, 78, 81, 82 are then substantially parallel to each other and perpendicular to the plane T.

In the embodiment shown in FIGS. 11 to 13, the templates 59, 60, 61 and 62 are integral with the spacer 11 and the connecting rods 69, 70, 79, 80 are linked to the deck 1 by articulations.

In other embodiments, not shown, the templates are the reverse secured to the deck 1 and the connecting rods are connected to the spacer 11 by joints.

Each bridge pylon may be provided with at least one assembly shown in Figures 11 to 13.

In one embodiment, the deck 1 is mounted integral with a pylon of the bridge, at least with respect to longitudinal stresses, the other pylons being provided with damping means.

In normal operation of the bridge, the shock absorbers described above with reference to the three embodiments of the invention, make it possible to limit the wind-related movements and ensuring proper operation of the seals pavement located at the ends of the structure, while ensuring dissipation of a major part of the mechanical energy associated with seismic waves without irreparable damage to the structure and preserving the safety of users.

It is recalled that the invention is in no way limited to the field of bridges with guy lines but also concerns the area of suspension bridges or generally that of structures in which two elements of civil engineering structure are likely to be driven on the move one in relation to the other.

Claims (18)

Earthquake-resistant device limiting the relative displacement of a first movable part (1, 11) relative to a second movable part (1, 11), these two movable parts (1, 11) being connected by connecting means, one at least part (14, 27, 37, 50, 57, 58) of these connecting means being able to undergo plastic deformation during relative movement of the parts movable relative to each other, the device comprising means for guide (18, 31, 45, 51, 59, 60, 61, 62) of the plastic deformation of the part (14, 27, 37, 50, 57, 58) of the connecting means able to deform plastically, the device being characterized in that it comprises at least a means of articulation intermediate between the part of the connecting means able to undergo plastic deformation and one of the moving parts (1, 11). Device according to claim 1, characterized in that the part of the connecting means capable of undergoing plastic deformation comprises at least a beam (14, 27, 37, 50, 57, 58), the means of articulation between the beam and one of the moving parts (1, 11) comprising at least one connecting rod (15, 27, 52, 69, 70, 79, 80). Device according to claim 2, characterized in that it comprises at less a plastically deformable beam forming part of the means of link capable of undergoing plastic deformation, and at least one connecting rod articulated at an extreme part of said beam, said connecting rod being articulated at one of the moving parts (1, 11), the beam and the connecting rod associated with this beam being arranged perpendicular to each other when placing in place of the device. Device according to claim 3, characterized in that a coupler hydraulic or mechanical is connected on the one hand to the connecting rod body and on the other part to the moving part with respect to which the connecting rod is articulated. Device according to any one of claims 1 to 4, characterized in that the beam (14, 27, 37, 50, 57, 58) is formed from a chosen material among the group comprising steels and metal alloys, composites with metal matrix. Device according to any one of claims 1 to 5, characterized in what the plastic deformation guide means include in minus a mechanical part defining a continuous curved surface or discontinuous against which the part of the connecting means bends (14, 27, 37, 50, 57, 58) capable of undergoing plastic deformation, during said deformation. Device according to any one of Claims 1 to 6, characterized in what the part of the connecting means capable of undergoing plastic deformation comprises a beam (14, 27) of which a first end portion (17, 30) is placed in a bending template (18, 31), integral with one of the parts mobile (1, 11), the other end part of said beam being articulated around at least one axis (16, 29) relative to a connecting rod (15, 28). Device according to any one of Claims 1 to 6, characterized in what the part of the connecting means capable of undergoing plastic deformation comprises at least one metal beam (50) of which a first part extreme extends into a housing of a first movable part (1, 11), the second end portion of said beam being articulated to a connecting rod (52), the intermediate section of said beam (50) which is located between the first end part and the point of articulation to said connecting rod being free to deform, the curved plastic deformation guide surface being located at the end of said housing of said moving part. Device according to any one of Claims 2 to 8, characterized in what the beam (14, 27, 37, 50, 57, 58) is of general section rectangular, the curved surface guiding the plastic deformation of said beam being in the form of a cylinder part. Device according to claim 9, characterized in that the surface of guiding the plastic deformation is formed by two curved surfaces arranged on either side of the beam and symmetrical about a plane median of said beam. Device according to any one of Claims 2 to 8, characterized in what the beam is of circular general section, the curved surface of guiding the plastic deformation being formed by a section of the surface of a torus analogous to the surface of a trumpet horn, of axis of symmetry substantially confused with that of the beam. Device according to any one of claims 1 to 11, characterized in that the first and the second moving part (1, 11) are made of concrete, in steel or the like. Engineering structure such as a bridge, characterized in that it comprises at least a seismic device as defined in one of claims 1 to 12. Engineering structure according to claim 13, characterized in that it is a cable-stayed bridge, comprising at least one pylon (5) provided with a spacer (11) forming one of the moving parts, the bridge deck forming the other part mobile. Bridge according to claim 14, its deck extending in a direction longitudinal D1, characterized in that it comprises at least one device seismic forming a longitudinal damper, said device comprising a plastically deformable metal beam, one end portion (17) is housed in a bending template (18) fixed to the deck (1), said beam extending at rest in a direction D2 substantially perpendicular to the direction D1 and being articulated to a connecting rod (15) extending in the direction D1, said connecting rod being itself articulated to a pylon leg of the bridge. Bridge according to claim 15, characterized in that the damper longitudinal is provided with a hydraulic or mechanical coupler (22) connecting the connecting rod body (15) to the articulation axis (20) of said connecting rod (15) of a leg of the pylon (5) of the bridge. Bridge according to any one of claims 15 or 16, characterized in what it includes at least two longitudinal shock absorbers arranged symmetrically with respect to a median plane P at one leg of a pylon (5). Bridge according to any one of claims 14 to 17, characterized in what it includes at least one seismic device forming a shock absorber transverse, said device comprising a metal beam (27), one of which first end part (30) is placed in a bending jig (31) integral with a leg of the pylon, said beam (27) being arranged according to the direction D1 and being articulated to a connecting rod (28), said connecting rod being placed at rest in a direction D2 substantially perpendicular to D1, said connecting rod (28) being articulated to the bulkhead (1) relative to an axis (35) substantially parallel to the articulation axis (29) of the beam (27) relative to the connecting rod (28).

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