US20230265623A1 - Structure for absorbing impact energy - Google Patents

Structure for absorbing impact energy Download PDF

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Publication number
US20230265623A1
US20230265623A1 US18/003,004 US202118003004A US2023265623A1 US 20230265623 A1 US20230265623 A1 US 20230265623A1 US 202118003004 A US202118003004 A US 202118003004A US 2023265623 A1 US2023265623 A1 US 2023265623A1
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United States
Prior art keywords
reinforcements
face
embankment
impact
main strength
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Pending
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US18/003,004
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English (en)
Inventor
Yassine BENNANI BRAOULI
Nicolas Freitag
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Soletanche Freyssinet SA
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Soletanche Freyssinet SA
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Assigned to SOLETANCHE FREYSSINET reassignment SOLETANCHE FREYSSINET ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BENNANI BRAOULI, Yassine, FREITAG, NICOLAS
Publication of US20230265623A1 publication Critical patent/US20230265623A1/en
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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00—Independent underground or underwater structures; Retaining walls
    • E02D29/02—Retaining or protecting walls
    • E02D29/0225—Retaining or protecting walls comprising retention means in the backfill
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F7/00—Devices affording protection against snow, sand drifts, side-wind effects, snowslides, avalanches or falling rocks; Anti-dazzle arrangements ; Sight-screens for roads, e.g. to mask accident site
    • E01F7/04—Devices affording protection against snowslides, avalanches or falling rocks, e.g. avalanche preventing structures, galleries
    • E01F7/045—Devices specially adapted for protecting against falling rocks, e.g. galleries, nets, rock traps
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F15/00—Safety arrangements for slowing, redirecting or stopping errant vehicles, e.g. guard posts or bollards; Arrangements for reducing damage to roadside structures due to vehicular impact
    • E01F15/14—Safety arrangements for slowing, redirecting or stopping errant vehicles, e.g. guard posts or bollards; Arrangements for reducing damage to roadside structures due to vehicular impact specially adapted for local protection, e.g. for bridge piers, for traffic islands
    • E01F15/145—Means for vehicle stopping using impact energy absorbers
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F7/00—Devices affording protection against snow, sand drifts, side-wind effects, snowslides, avalanches or falling rocks; Anti-dazzle arrangements ; Sight-screens for roads, e.g. to mask accident site
    • E01F7/04—Devices affording protection against snowslides, avalanches or falling rocks, e.g. avalanche preventing structures, galleries
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00—Independent underground or underwater structures; Retaining walls
    • E02D29/02—Retaining or protecting walls

Definitions

  • the invention relates to the field of structures for protection against accidental impacts of massive objects, corresponding for example to falling rocks in the mountains, or to the derailment of a train.
  • protective nets are known that are disposed so as to intercept the impacting objects.
  • These nets which are generally metallic, can stop impacts of up to 8 megajoules (MJ) by deforming, and have the advantage of being compact.
  • MJ megajoules
  • they entail numerous problems. These structures cannot be acted upon a plurality of times and they require significant maintenance. After having stopped a projectile, the anchoring points are damaged and it is necessary to carry out repairs. Maintenance of these structures is costly and frequent. Maintenance is also necessary due to the corrosion of the nets, which are generally disposed in the open air. This constraint is all the more important since these structures are generally situated in places that are difficult to access. On the other hand, these unattractive structures tend to degrade the landscape. In numerous territories, putting protective nets in place is not sufficient to make land exposed to falling objects constructible, the trend being to safeguard landscapes. These requirements are important in mountainous areas where land pressure is increasing.
  • a protective net is associated with a structure of the merlon type constituted of substantial embankments making it possible to completely block the impacts.
  • These structures make it possible to absorb higher energies, up to 30 megajoules, and require little maintenance. However, they occupy a large footprint on the ground, and are not always usable in practice.
  • EP 1 520 933 A1 describes a technique in which facing elements such as gabions are disposed on the front face of a reinforced soil structure and associated with a deformable material, such as recycled tires. Thus, in the event of stone impacts, damaged individual elements of the facing can be replaced.
  • the invention proposes a reinforced impact absorption structure that makes it possible to distribute the energy of the impact laterally so as to allow the thickness of the structure to be reduced. If the use of reinforcements is known, they are conventionally disposed in the depth of an embankment, parallel to the direction in which it is expected to be acted upon.
  • the object of the invention is a of impact energy, comprising an embankment having a first face exposed to impacts and reinforcements distributed within the embankment and having frictional interfaces with the material of the embankment.
  • the reinforcements comprise first reinforcements placed in a first reinforced region adjacent to the first face and having main strength directions forming an angle of less than 45° with the first face.
  • the structure can be of the merlon type and can be disposed orthogonally to a trajectory along which impacts are anticipated such that the impact against which protection is sought occurs in a direction having a strong component normal to the first face. It can also be a retaining wall disposed so as to prevent subsidence of stepped terrain in response to a substantial impact.
  • the embankment is preferably constituted of earth but can also have any type of material that is liable to absorb mechanical energy by interacting with the reinforcements.
  • the embankment has a certain granularity that allows it to have favorable mechanical behavior.
  • the embankment has a second face opposite the first face.
  • the reinforcements can then comprise second reinforcements placed in a second reinforced region adjacent to the second face and having main strength directions forming an angle of less than 45° with the second face.
  • the configuration of the absorption structure allows the friction mobilized at the first (or second, if applicable) reinforcements to have a significant contribution to the dissipation of the energy of a powerful impact occurring on the first (or second) face. This friction results from the deformation of the first (or second) face due to the impact.
  • the location of the first (or second) reinforcements within the first (or second) reinforced region, which is adjacent to the first (or second) face, and their orientation relative to this face allows effective dissipation without requiring a great depth of penetration into the structure. It is thus possible to obtain an absorption structure that is not too bulky perpendicular to the faces likely to be struck by objects of high kinetic energy.
  • the footprint on the ground is for example less than or equal to 10 m, preferably less than or equal to 5 m, even more preferably less than or equal to 3 m.
  • the reinforcements used are preferably reinforcements of the one-dimensional type, i.e. the mechanical strength that they exhibit is for the most part exerted in a single strength direction, the mechanical strength that they exhibit in the other directions being negligible compared to this one. They are, for example, strips, and not sheets or extended gratings.
  • the main strength direction of the reinforcement corresponds to the direction in which the reinforcement tends to propagate a mechanical stress when it is acted upon. It is generally the direction of the largest dimension of the reinforcement.
  • These reinforcements are disposed such that their main strength directions are substantially parallel to each other and to the one or more faces of the structure.
  • the main strength directions of the first reinforcements can be parallel to the first face of the embankment, and likewise for the second face, if appropriate. It is nevertheless possible, in certain cases, for their orientation to deviate a little from the plane of the first face, or from the plane tangent to the latter if the first face is not planar.
  • the angle formed between these main directions and the first face nevertheless has to remain an acute angle so that their projection onto the first face is longer than their projection in the direction perpendicular to the first face, and this gives good energy dissipation effectiveness in the event of impact in the perpendicular direction.
  • reinforcements in the extension of one another could therefore for example form a polygon matching the shape of the face.
  • a curved face will preferably have a large radius of curvature.
  • the first reinforcements In order not to weaken the embankment by creating preferential slip planes, it is advantageous to avoid as far as possible disposing the first reinforcements in the center of it. This is the reason why the reinforcements are predominantly disposed close to the one or more faces of the structure that are likely to receive impacts. This does not exclude the presence of reinforcements in the center of the embankment, but these will be in the minority.
  • the distribution of the reinforcements is heterogeneous in the thickness of the structure. The density of reinforcements is lower in regions that are remote from the flush faces than in the first reinforced region (or the second reinforced region) of the embankment.
  • the density of reinforcements is not necessarily continuously decreasing.
  • the reinforcements are regularly spaced but only in the reinforced regions close to at least one face of the structure. There may be regions less close to the faces of the structure in which the reinforcements are more widely spaced or even absent. These regions can however have other types of reinforcements, for example reinforcements oriented along the thickness of the structure.
  • the structure is capable of absorbing an impact having an energy greater than 2 MJ, preferably greater than 5 MJ. These energies correspond to stresses that protective merlons disposed in the mountains, for example, can conventionally suffer.
  • the plurality of reinforcements comprises reinforcements arranged so as to have ductile and not brittle behavior when the front face is acted upon by an impact in a normal direction.
  • An example of such an arrangement consists in limiting the direct connections between the reinforcements.
  • Two reinforcements arranged in successive segments along their main strength direction are for example disposed with a zone of mutual overlap between them, and leaving a layer of the material of the embankment between the reinforcements, and this makes it possible to introduce friction and to soften the transmission of lateral stress in order to avoid the reinforcements breaking.
  • This zone of mutual overlap is a function of the stiffness of the reinforcements, of the friction surface, of the breaking strength of the reinforcement.
  • the largest dimension of the reinforcements can also be critical and it is important not to use reinforcements of too large a dimension in order to prevent their breaking, still with a view to resilience allowing the structure to suffer a plurality of impacts without requiring repair.
  • FIG. 1 is a cross-sectional side view of a structure according to one embodiment of the invention.
  • FIG. 2 is a cross-sectional side view of a structure according to another embodiment of the invention.
  • FIG. 3 is a cross-sectional side view of a structure according to another embodiment of the invention.
  • FIG. 4 is a cross-sectional side view of a structure according to another embodiment of the invention.
  • FIG. 5 is a cross-sectional front view of the structure, the cross section being on the plane V-V indicated in any one of FIGS. 1 to 4 ;
  • FIG. 6 is a cross-sectional top view of a structure according to the embodiment of the invention in FIG. 3 ;
  • FIG. 7 is a cross-sectional top view of a structure according to another embodiment of the invention.
  • FIG. 8 is a view similar to that of FIG. 6 after an energy impact.
  • the structure for absorbing impact energy described below by way of example takes the form of a protective merlon used to intercept falling rocks that can weigh up to several hundred metric tons, for example close to mountain roads. Such falling rocks can carry energies in excess of 6 megajoules (MJ).
  • MJ megajoules
  • This protective merlon has a first face, or front face, 10 shown on the right in FIGS. 1 to 4 and a second face, or rear face, 20 shown on the left. These faces 10 , 20 can be substantially parallel as in FIGS. 1 and 3 . The rear face 20 can also be inclined relative to the front face 10 , as in FIGS. 2 and 4 .
  • the orientation of the rear face 20 in FIGS. 2 and 4 allows better dissipation of the mechanical energy in the ground but increases the footprint of the structure on the ground.
  • front face 10 is depicted as vertical in FIGS. 1 to 4 , it can also be inclined, in particular if increasing the stability of the structure, modifying the footprint on the ground or adapting to an impact trajectory that is anticipated to be oblique is required. Specifically, it is advantageous for the front face to be as far as possible perpendicular to the trajectory of the impact.
  • the merlon of the exemplary embodiment comprises an earthen embankment 15 delimited by the front and rear faces 10 , 20 , in which reinforcements 16 are disposed that have frictional interfaces with the material of the embankment.
  • These reinforcements 16 are, for example, strips that are regularly distributed in the vertical direction and extend horizontally, parallel to the front face 10 and to the rear face 20 , in a direction perpendicular to the section plane in FIGS. 1 to 4 . This orientation makes it possible to preferentially distribute the mechanical energy of an impact laterally rather than in the thickness of the protective merlon.
  • the reinforcements 16 are disposed in the regions of the embankment 15 that are acted upon the most in the event of an impact of which the energy has to be absorbed.
  • the reinforcements 16 consist of first reinforcements 16 placed in a first reinforced region 12 adjacent to the front face 10 .
  • a second reinforced region 22 is provided near the rear face 20 .
  • This second reinforced region 22 comprises second reinforcements 16 .
  • the central region of the merlon will not be provided with reinforcements 16 parallel to the faces 10 , 20 , so as to allow deformation of the merlon in the event of impact, so as not to weaken it.
  • secondary reinforcements 18 disposed transversely to the faces 10 , 20 can also be incorporated into the embankment 15 , so as to consolidate the whole.
  • the secondary reinforcements 18 can in particular connect the front and rear faces 10 , 20 .
  • the reinforcements 16 can be disposed over the entire width of the merlon.
  • reinforcements 16 are used that are disposed in successive segments along their main strength direction so as to partially overlap as illustrated in FIG. 5 .
  • Each zone 25 of mutual overlap between two successive reinforcements 16 has embankment material such that the reinforcements 16 are not in contact with each other.
  • the reinforcements 16 are disposed perfectly parallel to the front and rear faces as illustrated in FIG. 6 , so as to distribute the mechanical energy as laterally as possible.
  • the reinforcements can have a slight angle (which has to remain less than 45°) and be somewhat sunken into the thickness of the structure, as shown in FIG. 7 . They are nevertheless considered to be substantially parallel to the front face 10 and to the rear face 20 because their orientation remains predominantly lateral.
  • the main strength directions of the reinforcements 16 form an angle of less than 45° with the face 10 and/or 20 of the embankment 15 .
  • the reinforcements 16 can vary in height and have a slight slope. It is desirable for this slope to remain shallow so as to distribute the energy as laterally as possible.
  • FIG. 8 is a depiction similar to FIG. 6 after it has received a powerful and localized impact on its front face 10 shown at the bottom of the figure. It can be seen that the energy was able to be properly dissipated laterally by virtue of the reinforcements 16 . The reinforcements 16 did not break. They remain disposed in a configuration capable of damping other impacts.

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  • Engineering & Computer Science (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Architecture (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • General Engineering & Computer Science (AREA)
  • Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
  • Vibration Dampers (AREA)
US18/003,004 2020-06-25 2021-06-25 Structure for absorbing impact energy Pending US20230265623A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FRFR2006665 2020-06-25
FR2006665A FR3097574B1 (fr) 2020-06-25 2020-06-25 Structure d’absorption d’une énergie d’impact
PCT/FR2021/051170 WO2021260336A1 (fr) 2020-06-25 2021-06-25 Structure d'absorption d'une énergie d'impact

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US20230265623A1 true US20230265623A1 (en) 2023-08-24

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US18/003,004 Pending US20230265623A1 (en) 2020-06-25 2021-06-25 Structure for absorbing impact energy

Country Status (8)

Country Link
US (1) US20230265623A1 (fr)
EP (1) EP4172416A1 (fr)
JP (1) JP2023532885A (fr)
CA (1) CA3188111A1 (fr)
CL (1) CL2022003734A1 (fr)
FR (1) FR3097574B1 (fr)
PE (1) PE20230541A1 (fr)
WO (1) WO2021260336A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220213658A1 (en) * 2019-02-26 2022-07-07 Margaritelli Ferroviaria S.p.A. Safety end piece for road barriers

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2860529B1 (fr) * 2003-10-03 2006-12-15 France Gabion Ouvrage de genie civil, element individuel de construction et procede de renforcement d'un tel ouvrage
GB2544264A (en) * 2015-11-03 2017-05-17 Hesco Bastion Ltd Barrier
DE102017010375A1 (de) * 2017-11-09 2019-05-09 Jochen Schüssler Abtrenn- und Haltevorrichtung, Verfahren und Verwendung
FR3083551B1 (fr) * 2018-07-03 2020-12-25 Terre Armee Int Systeme de protection contre un impact

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220213658A1 (en) * 2019-02-26 2022-07-07 Margaritelli Ferroviaria S.p.A. Safety end piece for road barriers
US11905670B2 (en) * 2019-02-26 2024-02-20 Margaritelli Ferroviaria S.p.A. Safety end piece for road barriers

Also Published As

Publication number Publication date
JP2023532885A (ja) 2023-08-01
CL2022003734A1 (es) 2023-05-19
WO2021260336A1 (fr) 2021-12-30
CA3188111A1 (fr) 2021-12-30
FR3097574B1 (fr) 2023-03-31
EP4172416A1 (fr) 2023-05-03
FR3097574A1 (fr) 2020-12-25
PE20230541A1 (es) 2023-03-29

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Owner name: SOLETANCHE FREYSSINET, FRANCE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BENNANI BRAOULI, YASSINE;FREITAG, NICOLAS;REEL/FRAME:062195/0621

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