EP2663702B1 - Method for repairing a pylon, in particular for supporting catenaries, and pylon thus repaired - Google Patents

Description

The present invention relates to a pylon repair method including catenary supports, and a pylon thus repaired.

As is known per se, fixed electrical traction (catenary) installations for the supply of energy to railway equipment (locomotives) running on railway tracks are suspended from armaments which themselves are attached to pylons (support of catenary).

Conventionally, these pylons are made of often galvanized steel, and are of the HEA type, that is to say that they have a section "H", single or paired.

The structure of these pylons can be massive, or made in latticework.

Each pylon is embedded in a massive concrete poured into a dig in the ground.

This massif is surmounted by a concrete protection die surrounding the base of the pylon.

This protective die, which protects the base of the pylon against shocks from the ballast of the railway, has inclined faces.

This inclination makes it possible to avoid the stagnation of the rainwater around the base of the pylon.

A recurring problem is the corrosion of these pylons, and more particularly of their base coming out of the protective die: about twenty centimeters indeed, this base is very attacked especially when the protection die is cracked and thus retains the rainwater , which has the effect of gradually gnawing steel, and lead to a mechanical weakening of the pylon.

The complete replacement of each tower is very complex, since it is necessary to interrupt the traffic on the railway during the duration of the works.

In addition, such a replacement is expensive, and strongly consumer of steel.

There is therefore a recurrent need, not for replacement, but for the repair of corroded catenary poles.

Two techniques exist to date to carry out such a repair.

A first technique involves overmolding the base of the pylon with concrete.

However, this technique is expensive, and it does not necessarily stop corrosion: there is a risk of corrosion reappearing at the interface of the steel tower and concrete after a few years.

A second technique is to strengthen the base of the pylon with bolted brackets.

However, this technique has several disadvantages: it does not stop the corrosion, it allows to resume efforts in a single axis, it does not allow to accompany the dilations of the pylon (a game can then be created and the bolts are loosen), there is a risk of unscrewing either by vibration or by sabotage, and the implementation requires significant work.

The present invention is intended to provide such a repair method.

This object of the invention is achieved with a method of repairing a pylon having an "H" section, in particular catenary supports, having at least one weakened zone, in which two metal inserts of substantially parallelepipedic shape are placed in position. opposite, on both sides of the "H" core, as well as two metal plates on each wing of the "H", and these two inserts and these two metal plates are fixed simultaneously by means of a bandage of self-hardening resin matrix composite material.

The repair thus made constitutes a kind of towing device for the pylon, and it can be seen in tests which will be described later that the resistance provided by this hit is at least equal to or greater than that which may be present. a new pylon.

The placement of the two inserts and the two metal plates is optimal to obtain an isotropic resistance of the repaired pylon.

• éventuellement, on choisit des dimensions pour lesdits inserts métalliques et lesdites plaques métalliques de sorte que ces inserts et ces plaques dépassent des ailes du « H »,
• on place un mastic de transmission d'efforts entre ledit pylône et ledit insert : un tel mastic permet de réaliser une liaison intime entre cette zone et cet insert, et donc un comportement optimal vis-à-vis des efforts auxquels est soumis le pylône,

• on place un mastic de transmission d'efforts entre lesdites plaques métalliques et lesdites ailes,
• on utilise une résine bi-composant, conditionnée en unités de dosage,
• on utilise un mastic bi-composant, conditionné en unités de dosage.

According to other optional features of the pylon according to the invention:

• optionally, dimensions are chosen for said metal inserts and said metal plates so that these inserts and these plates protrude from the wings of the "H",
• placing a mastic for transmitting forces between said pylon and said insert: such mastic makes it possible to achieve an intimate connection between this zone and this insert, and therefore an optimal behavior vis-à-vis the forces to which the pylon is subjected,

• placing a mastic for transmitting forces between said metal plates and said wings,
• a two-component resin is used, packaged in dosage units,
• a two-component putty is used, packed in dosage units.

The use of two-component products previously dosed eliminates dosing operations, always difficult to achieve on a building site.

The present invention also relates to a pylon with an "H" section to which the repair method according to the above has been applied, comprising a weakened zone, two metal inserts of substantially parallelepipedal shape facing each other, arranged in said zone on either side of the core of the "H", and two metal plates disposed in said zone on each wing of the "H", these inserts and plates being fixed in said zone by means of said bandage.

• la figure 1 est une vue en coupe verticale d'un pylône de support de caténaires ancré dans le sol, comportant à sa base une zone Z à réparer,
• la figure 2 est une vue en coupe transversale du pylône de la figure 1, cette coupe étant réalisée dans la zone Z, selon la ligne II-II de la figure 1,
• la figure 3 est une vue en coupe selon la ligne III-III de la figure 2, du pylône de la figure 1,
• les figures 4 et 5 montrent, en vues en perspective, deux étapes successives de mise en oeuvre du procédé selon l'invention de réparation du pylône de la figure 1, dans la zone Z,
• la figure 6 est une vue en coupe analogue à celle de la figure 2 du pylône de la figure 1 après réparation dans la zone Z, cette figure 6 correspondant à la figure 5,
• la figure 7 représente de manière schématique et en élévation, une installation permettant de tester la résistance du pylône de la figure 1 une fois qu'il a subi une réparation conforme aux figures 4 à 6, et la figure 8 illustre la valeur du moment de renversement appliqué au pylône (axe Y : unité en m.daN), en fonction de l'angle de renversement du pylône (axe X : unité en degrés), respectivement pour un pylône neuf, pour un pylône usé et non réparé, pour un pylône usé et réparé conformément à l'invention avec une première distance de traction L, et enfin pour un deuxième pylône réparé conformément à l'invention, pour une deuxième distance de traction L.

Other characteristics and advantages of the present invention will emerge in the light of the description which follows, and on examining the appended figures, in which:

• the figure 1 is a vertical sectional view of a catenary support tower anchored in the ground, having at its base a zone Z to be repaired,
• the figure 2 is a cross-sectional view of the pylon of the figure 1 , this section being made in zone Z, along the line II-II of the figure 1 ,
• the figure 3 is a sectional view along line III-III of the figure 2 , from the pylon of the figure 1 ,
• the Figures 4 and 5 show, in perspective views, two successive stages of implementation of the method according to the invention of repairing the pylon of the figure 1 in zone Z,
• the figure 6 is a sectional view similar to that of the figure 2 of the pylon of the figure 1 after repair in zone Z, this figure 6 corresponding to the figure 5 ,
• the figure 7 schematically and in elevation, an installation for testing the resistance of the pylon of the figure 1 once it has been repaired in accordance with Figures 4 to 6 , and the figure 8 illustrates the value of the overturning moment applied to the pylon (Y axis: unit in m.daN), as a function of the overturning angle of the pylon (X axis: unit in degrees), respectively for a new pylon, for a worn pylon and not repaired, for a pylon worn and repaired according to the invention with a first pulling distance L, and finally for a second pylon repaired according to the invention, for a second pulling distance L.

In all of these figures, identical or similar references designate members or sets of identical or similar members.

We are now going back to figure 1 , on which there is shown a pylon 1, anchored in the ground S by means of an anchor mass 2, preferably formed of concrete poured into a dig.

The pylon 1 is preferably formed of galvanized steel, and has a HEA type section, that is to say substantially H-shaped, as can be seen in particular on the figure 2 .

The dimensions of the section of the H-shaped profile forming the tower 1, are, in the case of a railway application, given by the NF A 45-201 standard.

Pylon 1 is subject to corrosion, especially in its zone Z situated just above the anchor mass 2.

When the protective die is cracked, strong corrosion occurs in the interface area between this die and the base of the pylon.

There is thus very classically a loss of material on the two wings 3 of the profile forming the pylon 1.

As is visible on the Figures 2 and 3 this loss of material, indicated by the lines 5, typically takes place on a height hc of the order of twenty centimeters, according to the profile indicated in FIG. figure 3 : loss of material increasing from the soil to about twenty centimeters above the ground.

This loss of material is critical, especially as it takes place in the area of tower 1 where the bending moment is highest, when this pylon is subjected to various efforts, including the weight of the supported installation (catenary + catenary support arm), as well as the various external forces, and in particular those caused by the wind.

Under these conditions, it is understood that it is essential to ensure that the zone Z of the pylon remains perfectly healthy, and that the amount of material required for the stability of the pylon is not affected.

Until now, one of the only truly effective solutions was to simply remove the used pylon 1, and replace it with a new pylon.

Besides the fact that this solution required a stop of the traffic on the railway, it was obviously expensive, on the one hand in manpower and material, and on the other hand in galvanized steel lost.

The present invention thus provides an economical, practical and elegant solution for extending the life of a pylon having corrosion-related wear at its base.

The method according to the invention consists in placing at least one insert, and preferably two inserts 7a, 7b (see Figures 4 to 6 ), in each of the spaces defined by the two wings 3a, 3b of the profile of the pylon 1, in the zone Z.

The inserts 7a and 7b are preferably parallelepipedal, and preferably metal.

These inserts 7a and 7b can be dimensioned so as to slightly exceed the volumes defined by the two wings 3a and 3b, as can be seen in FIG. figure 6 .

Prior to the introduction of these inserts into these volumes, the cavities defined by the two wings 3a, 3b are coated with a force-transmitting mastic, preferably formed from two previously dosed components.

Once the two inserts 7a and 7b have been positioned in the cavities defined by the two wings 3a and 3b, on a height substantially corresponding to the corroded height hc (see figure 3 ), there is reported to the outside of the two wings 3a and 3b two metal plates 9a and 9b, the force transmission mastic having been previously coated on the outer faces of the wings 3a and 3b.

As is visible on the figure 6 , the two metal plates 9a and 9b may exceed the length of the wings 3a and 3b substantially the same value as the two inserts 7a and 7b.

We thus arrive at the configuration represented in figure 4 , in which the two inserts 7a and 7b on the one hand, and the two metal plates 9a and 9b on the other hand, have been positioned in the corroded zone Z.

Subsequently, the assembly thus formed is striped by means of a composite material 11 (see Figures 5 and 6 ), formed of a Kevlar®-type fiber web impregnated with a self-hardening resin.

This self-hardening resin is preferably obtained by mixing two previously measured components, the combination of these two components performing a rapid polymerization causing extreme hardening of the composite material band 11.

By "self-hardening", it is meant that the resin cures simply by mixing the two components without any external energy input (heat or otherwise).

It is understood that at the end of this repair, the pylon 1 is reinforced in its zone Z, by a set of metallic materials on the one hand and composite on the other hand, cooperating intimately and isotropically, and remedying the material deficit caused by the corrosion of this pylon.

It will be noted moreover that the implementation of the method according to the invention is extremely simple, and requires very little equipment.

The figure 7 indicates an installation for testing the resistance of a pylon 1 to a force applied to its top.

More precisely, this force T is applied by a cable 13 fixed to the ground S at a height e of this ground, and at a distance L from the foot of this pylon 1.

A traction member 17, such as a tire, makes it possible to increase little by little the value of the tension T applied to the cable 13.

A dynamometer 19 makes it possible to measure the value of this voltage T.

• pylône dont la base a été corrodée et qui n'a subi aucune réparation (pylône 2),
• premier pylône dont la base a été corrodée et qui a subi une réparation conformément au procédé selon l'invention (pylône 3 - distance de traction L = 29,2 m), et
• deuxième pylône dont la base a été corrodée et qui a subi une réparation conformément au procédé selon l'invention (pylône 4 - distance de traction L = 28,8 m).

For purposes of illustration, and in a nonlimiting manner, tests have been carried out to characterize the reinforcement of a pylon having a section of HEA 200 type, for the following cases:

• pylon whose base has been corroded and has not been repaired (pylon 2),
• first pylon whose base has been corroded and which has been repaired according to the method according to the invention (pylon 3 - pulling distance L = 29.2 m), and
• second pylon whose base was corroded and which has been repaired according to the method according to the invention (pylon 4 - pulling distance L = 28.8 m).

It should be noted that such tests could also have been carried out for pylons with a section other than HEA 200.

The difference between the tests relating to the last two towers lies in the different values of L (distance between the pylon 1 and the attachment point 15 of the cable 13 to the ground S).

For each of the four towers mentioned above, the test shown in FIG. figure 7 , in which the tension T is gradually increased by means of the puller 17.

An inclinometer 21 fixed on the pylon 1 makes it possible to measure the angle variation of the pylon 1 with respect to the vertical, as the tension T is increased by means of the firer 17.

By reading the corresponding voltage values on the dynamometer 19, it has been possible to establish, for each of the four aforementioned pylons, the graph represented in FIG.

This gives four curves C1, C2, C3, C4, respectively corresponding to the pylons 1, 2, 3 and 4.

As can be seen in particular with respect to the tower 2, each of the curves C1 to C4 comprises on the one hand a substantially rectilinear portion E, and on the other hand a curved portion P.

The substantially rectilinear portion E corresponds to the elastic deformation of the pylon, and the curved portion P corresponds to the plastic deformation, that is to say irreversible, of this pylon.

The transition threshold between the elastic and plastic parts of each of the curves C1, C4 is indicated respectively by the references S1 to S4, in FIG.

As can be seen from the examination of the figure 8 , pylons 3 and 4, that is to say those which have been repaired according to the method of the invention, have significantly higher critical moments (respectively 12000 and 13000 m.da.N) to that (7300 m .da.N) of pylon 2 having not been repaired.

Even more surprising is that the critical moments of pylons 3 and 4 are also greater than that of pylon1, nine.

As can be understood in the light of the foregoing, the method according to the invention, simple and inexpensive to implement, and requiring no complete replacement of existing pylons, can restore excellent mechanical strength for a tower having suffered significant corrosion in the vicinity of its anchor.

It was furthermore possible to verify that the repair according to the invention offered an excellent guarantee of durability, in particular vis-à-vis the external aggressions (ballast projection, rainwater, ultra-violet).

For all of these reasons, the method according to the invention offers a very elegant solution to give new life to towers for which there were no other solutions so far as a replacement identical .

Claims (7)

1. A method for repairing a pylon exhibiting an "H"-shaped section (1), in particular supports of overhead lines, exhibiting at least one weakened area (Z), in which two substantially parallelepiped-shaped metallic inserts (7a, 7b) are placed facing each other, on either side of the web of the "H", as well as two metallic plates (9a, 9b) on each wing (3a, 3b) of the "H", and these two inserts (7a, 7b) and these two metallic plates (9a, 9b) are simultaneously fixed by means of a composite material bandage (11) with a self-curing resin matrix.
2. The method according to claim 1 wherein dimensions for said metallic inserts (7a, 7b) and said metallic plates (9a, 9b) are chosen so that these inserts (7a, 7b) and these plates (9a, 9b) possibly protrude from the wings (3a, 3b) of the "H".
3. The method according to any of claims 1 or 2, wherein a mastic of transmission of forces is placed between said pylon (1) and said insert (7a, 7b).
4. The method according to any one of the preceding claims, wherein a mastic of transmission of forces is placed between said metallic plates (9a, 9b) and said wings (3a, 3b).
5. The method according to any of claims 3 or 4, wherein a bi-component mastic, packaged in dosage units, is used.
6. The method according to any one of the preceding claims, wherein a bi-component resin, packaged in dosage units, is used.
7. A pylon with an "H"-shaped section (1) to which has been applied the repair method in accordance with any one of the preceding claims, comprising a weakened area (Z), two substantially parallelepiped-shaped metallic inserts (7a, 7b) facing each other, disposed in said area (Z) on either side of the web of the "H", as well as two metallic plates (9a, 9b) disposed in said area (Z) on each wing (3a, 3b) of the "H", these inserts (7a, 7b) and these plates (9a, 9b) being fixed in said area (Z) by means of said bandage (11).

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