EP2821552B1 - Gateway and method for producing such a gateway - Google Patents

Description

The present invention relates to a gateway. By footbridge, we mean any construction work spanning an obstacle and allowing the movement of pedestrians or vehicles. The invention particularly relates to crossing structures of less than about 2.5 meters in length. The invention also relates to a method for producing such a gateway.

It is known bridges having a first abutment and a second abutment between which extend longitudinal beams having ends integral with the abutments. Longitudinal beams are most often prefabricated while abutments are obtained by casting concrete on site in excavations that are dug into the ground before being surmounted by formwork. The ends of the beams are then fixed to the abutments after removal of the formwork. Guardrail posts are then bolted to the abutments by means of inserts sealed in the abutment concrete. Reference is made to EP 2 549 028 A1 and EP 1 258 565 A1 .

Formwork production requires skills. Obtaining abutment having a shape and an aesthetic surface condition further complicates the task of the formers.

In addition, the positioning and fixing of the beams are made delicate by the weight and bulk of these.

An object of the invention is to provide a means for simplifying the realization of these bridges while ensuring their strength and appearance.

For this purpose, it is provided, according to the invention, a bridge having a first abutment and a second abutment between which longitudinal beams have ends having integral ends abutments, the first abutment comprises a concrete block of a foundation that receives a bottom portion of a frame and is embedded in the ground, and a lost form cap capping an upper portion of the frame, the cap having a peripheral wall that has a lower edge embedded in the concrete block foundation and which is surmounted by an upper wall pierced with at least one concrete introduction opening in the cap, the cap having openings for receiving the ends of the longitudinal beams in such a way that they are taken in the concrete introduced into the hat.

Thus, the hat provides the abutment most of its shape and makes superfluous the use of additional forms.

According to an advantageous characteristic, the bridge comprises at least one guard having at least two posts each fixed on one of the abutments, the integral post of the first abutment being received in an opening of the cap and having a lower end embedded in the concrete block foundation.

The pole fixing area is thus under the hat so that it is completely invisible. It is also particularly resistant because the lower end of the post is embedded in the foundation concrete block.

Advantageously, the bridge in which the beams are of flat shape and have a lower surface provided with a projecting longitudinal rib, the receiving openings of the beam ends being arranged to receive each a portion of rib so that the beams have their lower surface resting on the upper wall of the hat.

The ribs facilitate the positioning of the beams whose lower surface will rest on the upper wall of the cap.

The invention also relates to a method for producing a gateway of the above type.

Other features and advantages of the invention will become apparent on reading the following description of a particular non-limiting embodiment of the invention.

• la figure 1 est une vue en perspective d'une passerelle selon l'invention ;
• la figure 2 est une vue de dessus d'un des chapeaux de la passerelle selon l'invention ;
• la figure 3 est une vue en coupe de ce chapeau selon la ligne III-III de la figure 2 ;
• la figure 4 est une vue agrandie en coupe transversale d'une des poutres de la passerelle selon l'invention ;
• la figure 5 est une vue partielle en perspective d'une des culées de cette passerelle ;
• la figure 6 est une vue en coupe transversale d'une des culées réalisées selon une variante de l'invention.

Reference will be made to the appended drawings, among which:

• the figure 1 is a perspective view of a gateway according to the invention;
• the figure 2 is a top view of one of the gateway hats according to the invention;
• the figure 3 is a sectional view of this hat along line III-III of the figure 2 ;
• the figure 4 is an enlarged cross-sectional view of one of the beams of the bridge according to the invention;
• the figure 5 is a partial perspective view of one of the abutments of this bridge;
• the figure 6 is a cross-sectional view of one of the abutments made according to a variant of the invention.

With reference to Figures 1 to 5 , the bridge, generally designated 1, is intended to span a trench T formed in the ground S.

The bridge 1 comprises abutments, generally designated 2, between which longitudinal beams, generally designated 30, extend, having ends integral with the abutments 2.

The beams 30 are of flat shape and have a lower surface 31 provided with a longitudinal rib 32 projecting.

Each abutment 2 comprises a foundation concrete block 3 which is embedded in an excavation F dug in the ground S on one side of the trench T. The foundation concrete block 3 has a surface flush with the ground S. The foundation concrete is of the C16 / 20 type.

The foundation concrete block 3 receives a lower portion of a metal frame 4 having an upper portion which protrudes from the foundation concrete block 3 and which is capped by a loose formwork cap generally designated 5 .

The cap 5 has a peripheral wall 6 with a trapezoidal contour, which has a lower edge embedded in the foundation concrete block 3 and which is surmounted by an upper wall 7.

The cap 5 is filled with a type C20 / 25 cementitious concrete and has an upper wall 7 which is pierced with openings 8 for introducing the concrete into the cap 5.

The cap 5 has openings 9 for receiving the ends of the beams 3. The openings 9 have the form of rectangular notches extending astride the upper wall 7 and a long side of the peripheral wall 6. The openings 9 are arranged such that the ends of the beams 3 are made in the concrete introduced into the cap 5. More precisely here, the ends of the ribs 32 are each received in one of the openings 9 so that the end portion of the lower surface 31 of each beam 30 rests on the upper wall 7 of the caps 5.

The upper wall 7 is pierced at each of its ends with an opening 10 for the passage of a pole.

Indeed, the bridge 1 here comprises two guardrails, generally designated 11, extending parallel to the beams 3 on each side of the bridge 1.

Each railing 11 comprises two posts 12 each fixed to one of the abutments 2 and cables 13 having ends attached to the posts to extend therebetween. Each post 12 is received in one of the openings 10 of one of the caps 5 and has a lower end embedded in the foundation concrete block 3. More precisely, said lower end is secured to a plate 14 resting on a concrete pad. foundation which extends to the bottom of the excavation F and which is embedded in the foundation concrete block 3 with the plate 14 and the lower end of the post 12.

Each cap 5 is covered with a facing plate 15 which is fixed, here by sealing, on the upper wall 7 of the cap 5 and closes the openings 8. The facing plate 15 has a grooved upper surface to form a non-slip surface and inclined to extend from an edge of the upper wall 7 opposite the beams 30 to the upper surface of the beams 30.

The caps 5, the beams 30 and the facing plates 15 are made of concrete. Alternatively, the beams 30 may be made of wood or metal.

The method for producing this gateway will now be described. The footbridge 1 in question spans a trench approximately 2.30 m wide and has a circulation width of 1.20 m.

The caps 5, the beams 30 and the facing plates 15 are first prefabricated in the factory.

• y déposer l'armature 4 de telle manière que l'armature 4 dépasse du niveau supérieur du sol S. La fouille F a par exemple une longueur De 1,80 m et une largeur de 0,50 m. La fouille F a une profondeur suffisante pour atteindre une couche hors-gel de portance supérieure à 2 bars (une profondeur de 0,60 m est généralement suffisante).

For each abutment 2, the process starts with digging an excavation F in soil S.

• deposit the armature 4 in such a way that the armature 4 protrudes from the upper level of the ground S. The excavation F has for example a length of 1.80 m and a width of 0.50 m. The excavation F has a sufficient depth to reach an anti-freeze layer of lift greater than 2 bars (a depth of 0.60 m is generally sufficient).

Two foundation concrete blocks are then formed at each end of the bottom of the excavation F and leveled at the bottom of the excavation F. The foundation concrete is for example of the C16 / 20 type.

One of the posts 12 secured to the plates 14 is then disposed on each pad, the plate 14 resting on the pad.

The armature 4 is then threaded onto the posts 12 which have a height such that they protrude from the upper part of the armature 4, said upper part projecting from the ground S out of the excavation F. The armature 4 is keyed on the plates 14.

The process continues with the step of casting foundation concrete in the excavation F to the ground level S. The foundation concrete, type C16 / 20, is preferably relatively firm.

The cap 5 is threaded onto the posts and the frame 4 after pouring the foundation concrete and is wedged on the frame 4 so that the cap 5 covers the frame 4 and the lower edge of the peripheral wall 6 be engaged in foundation concrete.

Then let the foundation concrete be taken.

After lengthening the beams 30 if necessary, a sealing concrete is poured through the openings 8 in the cap 5 of each abutment 2 so as to fill said cap 5. The sealing concrete is a relatively fluid concrete type C20 / 25 .

The method is continued by the step of placing the ribbed ends 32 of the beams 30 in the openings 9 so that the beams 30 have the end portions of their lower surface 31 which rest on the upper walls 7 of the two caps 2 abutments 2. Potential reflux of sealing concrete is rapidly cleaned.

Then, let the concrete seal. It will be noted that the hats 5 thus form lost formwork.

The strands 13 are then stretched between the posts 12 and the facing plates 15 are glued to the upper walls 7 of the caps 5.

Of course, the invention is not limited to the embodiments described but encompasses any variant within the scope of the invention as defined by the claims.

In particular, according to a variant of the invention, the foundation concrete is allowed to take before arranging the cap.

Thus, we simply put the hat on the foundation concrete block, which simplifies the implementation.

In this variant, it is possible to make a guardrail. For this purpose, for each abutment, a post 12 is fixed on the foundation concrete taken and the cap 5 has an opening 10 for the passage of the post so that the cap can be threaded onto the post and the reinforcement, after the taking foundation concrete. The method comprises the subsequent step of securing to the posts a guardrail extending parallel to the beams.

In another variant, the hat may have another shape. The peripheral wall of the cap may for example have a rectangular contour.

Claims (12)

1. Bridge (1) including a first abutment (2) and a second abutment (2) between which extend longitudinal beams (30) having ends attached to the abutments, characterized in that the first abutment includes a concrete foundation block (3) which receives a lower portion of a armature (4) and is embedded in the ground and an absorptive formwork cap (5) capping an upper part of the armature, the cap having a peripheral wall (6) which has a lower edge embedded in the concrete foundation block and is surmounted by an upper wall (7) pierced by at least one opening for introduction of concrete into the cap, the cap including openings (9) for receiving the ends of the longitudinal beams so that they are set in the concrete introduced into the cap.
2. Bridge according to claim 1, including at least one guardrail (11) including at least two posts (12) each fixed to one of the abutments (2), the post attached to the first abutment being received in an opening (10) of the cap (5) and having a lower end embedded in the concrete foundation block (3).
3. Bridge according to claim 1 or 2, wherein the beams (30) are flat in shape and have a bottom surface (31) with a projecting longitudinal rib (31), the openings (9) receiving the beam ends each being adapted to receive a rib portion so that the beams (30) have their lower surface resting on the upper wall (7) of the cap (5).
4. Bridge according to any one of claims 1 to 3, wherein the beams (30) are made of concrete.
5. Bridge according to any one of the preceding claims, wherein the cap (5) is made of concrete.
6. Bridge according to any one of the preceding claims, wherein a facing plate (15) is fixed to the upper wall (7) of the cap (5) and closes the opening (8) for the introduction of concrete.
7. Bridge according to any one of the preceding claims, wherein the second abutment (2) is identical to the first abutment (2).
8. Method of making a bridge according to claim 7, the caps (5) and the beams (30) being prefabricated, the method comprising for each abutment (2) the steps of:

   - digging a trench (F) in the ground (S),

   - placing the armature (4) therein so that the armature is partly above ground,

   - pouring foundation concrete into the trench,

   - placing on top of the armature a prefabricated absorptive formwork cap so that the cap caps the armature,

   - pouring fixing concrete into the cap,

   - placing the beam ends so that the beams extend between the abutments,

   - allowing the fixing concrete to set.
9. Method according to claim 8, wherein the cap is placed before the foundation concrete sets so that the cap has a lower edge engaged in the foundation concrete, fixing concrete being poured after the concrete of the foundation has set.
10. Method according to claim 9, wherein, prior to placing the armature, at least one concrete foundation slab is formed on the bottom of the trench and at least one post (12) is disposed on the slab, the armature (4) being threaded over the post, which has a height such that it projects above the upper part of the armature, and the cap (5) including an opening (10) for the passage of the post so that the cap can be threaded over the post and the armature after pouring the foundation concrete, the method including the subsequent step of fixing to the posts a handrail extending parallel to the beams.
11. Method according to claim 8, wherein the foundation concrete is allowed to set before placing the cap.
12. Method according to claim 11, wherein a post (12) is fixed to the set foundation concrete and the cap (5) includes an opening (10) for the passage of the post so that the cap can be threaded over the post and the armature after the foundation concrete has set, the method including the subsequent step of fixing to the posts a handrail extending parallel to the beams.

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