WO2000026474A1 - Semirigid, high-impact-energy-control, high-impact-energy-absorption guardrail, in particular for bridges and similar road structures - Google Patents

Semirigid, high-impact-energy-control, high-impact-energy-absorption guardrail, in particular for bridges and similar road structures Download PDF

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Publication number
WO2000026474A1
WO2000026474A1 PCT/IT1999/000346 IT9900346W WO0026474A1 WO 2000026474 A1 WO2000026474 A1 WO 2000026474A1 IT 9900346 W IT9900346 W IT 9900346W WO 0026474 A1 WO0026474 A1 WO 0026474A1
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WO
WIPO (PCT)
Prior art keywords
guardrail
post
rail
posts
impact
Prior art date
Application number
PCT/IT1999/000346
Other languages
French (fr)
Inventor
Mariano Pernetti
Original Assignee
Ilva Pali Dalmine S.R.L.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ilva Pali Dalmine S.R.L. filed Critical Ilva Pali Dalmine S.R.L.
Priority to AU10761/00A priority Critical patent/AU1076100A/en
Publication of WO2000026474A1 publication Critical patent/WO2000026474A1/en

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Classifications

    • 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
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0407—Metal rails
    • E01F15/0423—Details of rails
    • 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
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0407—Metal rails
    • E01F15/0423—Details of rails
    • E01F15/043—Details of rails with multiple superimposed members; Rails provided with skirts
    • 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
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0407—Metal rails
    • E01F15/0438—Spacers between rails and posts, e.g. energy-absorbing means
    • 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
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0461—Supports, e.g. posts
    • 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
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0476—Foundations
    • 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
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0492—Provisions for guiding in combination with rails, e.g. tire-gutters

Definitions

  • the present invention relates to a semirigid, high-impact-energy-control, high-impact-energy- absorption guardrail, in particular for bridges and similar road structures.
  • Guardrails of the above type are known in which one or more shaped strips, normally with two or three ridges and aligned vertically, are connected by spacers to a number of posts fitted to the edge of the structure. Upon impact, the posts of such guardrails undergo severe deformation resulting in a dangerous outward shift of the guardrail .
  • Guardrails have been proposed in which the top strip is strengthened by a rear rail acting as a tie.
  • the top strip is not high enough to withstand impact by heavy-duty vehicles, and the rear strengthening rail fails to provide for effectively improving the rigidity of the strip.
  • the posts of known guardrails are so fitted to the edge of the structure as to be extremely difficult and expensive to replace; and, for known guardrails to be fitted effectively to the structure and to deform upon impact, a fairly wide edge is * required, which is rarely available in the case of bridges, viaducts and the like.
  • bridges and viaducts along modern main roads having separate lanes for each traffic direction are normally also divided into opposite traffic lanes; and, normally, identical guardrails are erected indifferently on the right or left of the structure, despite being subjected to impact by opposite sides of vehicles of different types and/or traveling at different speeds.
  • known guardrails are designed and sized to withstand impact in both directions, thus resulting in considerable waste in material .
  • a guardrail of the above type which provides for effectively retaining the vehicle and effectively withstanding impact by each side of the vehicle .
  • a semirigid, high- impact-energy-control, high- impact-energy-absorption guardrail comprising a number of posts located a predetermined distance apart; and at least one shaped strip for withstanding impact by a vehicle; said shaped strip being connected to said posts by corresponding spacers; characterized in that at least some of said posts are connected to the respective adjacent posts by first struts so oriented as to exert traction in the event of impact at an impact angle of less than 90°.
  • the guardrail is particularly suitable for bridges and similar road structures, and comprises a rail located over said shaped strip, with the center line of the rail at an off-ground height at least twice that of the center line of said shaped strip, so as to withstand impact by heavy vehicles with a high center of gravity; said first struts being connected at said rail .
  • This further object is achieved by a semirigid guardrail wherein each post is fitted, with a 3- to 10- degree tilt inwards of the lane, by means of a base plate having at least two slots for engaging corresponding ties defined by studs on a portion of the structure.
  • Figure 1 shows a front view of a semirigid guardrail in accordance with the invention
  • Figure 2 shows a top plan view of the Figure 1 guardrail
  • Figure 3 shows a larger-scale section alont ⁇ line III-III in Figure 1;
  • Figure 4 shows a larger-scale portion of Figure 2
  • FIG. 5 shows the Figure 3 section with parts removed
  • Figure 6 shows a partially sectioned front view of Figure 5 ;
  • Figure 7 shows a section along line VII-VII in Figure 5 ;
  • Figure 8 shows a partial, larger-scale section along line VIII-VIII in Figure 5;
  • Figure 9 shows a partial, larger-scale section along line IX-IX in Figure 3;
  • Figure 10 shows a spreadout view of a Figure 3 detail
  • Figure 11 shows a variation of the Figure 10 detail
  • Figure 12 shows a front view of a detail in Figure i;
  • Figures 13 and 14 show larger-scale front and top plan views of a further detail in Figure 1;
  • Figure 15 shows a larger-scale detail of Figure 2
  • Figure 16 shows a larger-scale section along line XVI-XVI in Figure 15;
  • Figure 17 shows a front view of a detail in Figure 3;
  • Figures 18 and 19 show views in perspective of a further two components of the guardrail.
  • Number 1 in Figures 1 and 2 indicates as a whole a portion of a structure, e.g. a bridge or flyover, of a traffic lane in the direction of the arrow.
  • the bridge On each side of the lane, the bridge has a curb 2 made of stone, reinforced concrete or iron, and fitted with a corresponding semirigid guardrail 3.
  • Each guardrail 3 is modular, and comprises a number of uprights or posts 4 equally spaced 1.333 m apart, which forms each span of the guardrail.
  • Posts 4 support at least one known rail or shaped strip 5 having three ridges and two grooves 6 ( Figure 3) ;
  • strip 5 is defined by segments of at least 4.380 m in length, each of which is connected to four posts 4 ( Figures 1 and 2), i.e. covers three spans between posts 4; and each segment of strip 5 defines a four-meter-long module 7 of guardrail 3.
  • Guardrail 3 also comprises a rail 46 located over strip 5; strip 5 and rail 46 are connected to posts 4 by corresponding spacers 24 and 48 as described later on; and posts 4, strip 5, rail 46 and spacers 24 and 48 are advantageously made of strong, quality steel, e.g. Fe430B to Italian standard UNI EN 10025.
  • the two guardrails 3 of respective curbs 2 of the lane differ from each other, so as to react, as explained later on, more effectively to vehicle impact at an angle of less than 90°.
  • Figures 1 and 2 show the guardrail 3 of curb 2 on ' the left-hand side of the lane.
  • each post 4 ( Figure 3) is fitted to curb 2 with the post axis tilted inwards of the lane by a given angle advantageously ranging between 3° and 10° and preferably of 7° .
  • Post 4 is defined by a channel having a flat wall 8 crosswise to strip 5 and facing oncoming traffic.
  • the post 4 channel also comprises a front wing 9 ( Figures 5-8) ; and a rear wing 10 having a bent edge 11.
  • Wings 9 and 10 are located on the downstream side of post 4 in the lane direction; the bottom end of post 4 is reinforced by two brackets 12 and 13 , each having a sloping edge with a strengthening ridge 14 ; bracket 12 is trapezoidal and welded to flat wall 8 of the post 4 channel ; and bracket 13 is in the form of an irregular pentagon, and is welded to the edge of front wing 9 and to the bent edge 11 of wing 10 of the channel .
  • Post 4 is connected at the desired angle to a rectangular base plate 15, fitted to curb 2, by welding the bottom edges of brackets 12 and 13 and the bottom edge of wing 10 of the channel to plate 15.
  • Plate 15 comprises two slots 16 ( Figure 4) located to the side of brackets 12 and 13 and aligned parallel to strip 5; and two holes 17 aligned transversely with slots 16, but offset longitudinally with respect to each other so that the hole 17 downstream in the traffic direction is • closer to the corresponding slot 16.
  • the amount by which holes 17 are offset may advantageously equal half the distance between slots 16. Slots 16 and holes 17 are engaged by four ties 18
  • Arc-shaped portion 23 extends about two-thirds of the total length of plate 21; the bottom portion 22 is about twice as long as the top portion 22; and slot 20 and plate 21 provide for a high degree of elasticity of the post " portion between brackets 12, "13 and spacer 24 of strip 5.
  • Spacer 24 provides for keeping strip 5 substantially parallel to post 4, and is defined by a substantially rectangular plate 26 ( Figure 10) having a top and bottom side 27, 28 perpendicular to the axis of post 4, and a front and rear side 31, 29 parallel to the post axis. Side 29 is positioned substantially flush with wing 10 of post 4, while side 31 projects from post 4 and has two triangular openings 32.
  • wing 33 ( Figure 9) for supporting strip 5 ( Figure 3) with the center line at a height of about 700 mm.
  • wing 33 has two holes 34 corresponding with the two grooves 6 of strip 5; and each groove 6 has horizontal-axis slots 36 ( Figure 12) spaced the same distance apart as posts 4 to enable strip 5 to be fitted to wing 33 of each spacer 24 by means of two bolts with respective plates in between.
  • plate 26 has two opposite U-bent edges 38 and 39 ( Figures 3 and 9) , the bend lines of which are shown by dash lines in Figure 10. Bent edges 38 and 39 provide for strengthening spacer 24, and each have a projecting portion which fits inside the cavity of a respective outer ridge of strip 5. Finally, plate 26 is strengthened by a rib defined (by a T section 41, which is welded by the crosspiece to " plate 26, between the center line of side 29 and the center line of wing 33, and is therefore also perpendicular to the axis of post 4. Plate 26 has two slots 42 for receiving respective bolts 43, which also engage two holes 44 ( Figure 5) , formed in wall 8 of post 4, with the interposition of slot-cover plates.
  • the connection of spacers 24 to posts 4 provides for gradually dissipating impact energy and decelerating vehicles of any height, while enabling strip 5 to remain substantially parallel to itself.
  • the top rail 46 ( Figure 3) is made of sheet metal shaped so as to have a cross section substantially in the form of the Greek letter omega ( ⁇ ) .
  • Each segment of rail 46 is 3.950 m long and therefore sufficient for each module 7.
  • Posts 4 are of such a height as to position the center line of rail 46 at an off-ground height of over twice that of the center line of shaped strip 5, so that rail 46 provides for withstanding impact by vehicles with a high center of gravity, such as industrial vehicles and buses .
  • the center line of rail 46 may advantageously be located at a height of about 1.5 m.
  • rail 46 comprises a central wall 47 connected to each post 4 by a spacer 48 perpendicular to the axis of post 4; two walls 49 bent slightly less than 90° with respect to central wall 47 so as to be slightly flared; and two flanges 50 substantially parallel to central wall 47.
  • Spacer 48 is made of sheet metal bent into a C with a front wing 51 ( Figures 13 and 14) , which is bent
  • At least one of holes 52 and the corresponding hole 55 are engaged by a bolt connecting spacer 48 to rail 46.
  • Spacer 48 also has two offset slots 53 (Figure 3) for receiving respective bolts 54, which also engage two corresponding holes 56 ( Figure 5) , formed in wall 8 of post 4, via the interposition of perforated plates.
  • Such a connection provides for gradually dissipating the impact energy of vehicles with a high center of gravity, and also aids in decelerating the vehicle while maintaining rail 46 substantially parallel to itself.
  • Guardrail 3 also comprises two chains 58 and 59 ( Figures 3 and 17) , each defined by segments of a flat section of the same length as module 7.
  • Each chain 58, 59 has slots 60 for receiving two corresponding bolts, which also engage two corresponding holes 61, 62 ( Figure 6) in rear wings 10 of posts 4. More specifically, hole 61 is located at spacer 48 ( Figure 3) and provides for connecting chain 58, while hole 62 is located just beneath spacer 48 and provides for connecting chain 59.
  • Guardrail 3 also comprises a number of struts 63 indicated by dot-and-dash lines in Figure 2 and hereinafter referred to as top strutjs .
  • Each top strut 63 has a bent perforated end 64 (Figure 18) located between bottom chain 59 and wing 10 of each post 4, and is connected to bottom chain 59 and wing 10 by the bolt engaging slot 60 in chain 59 and hole 62 in wing 10.
  • each top strut 63 is located between wall 47 of rail 46 and the bent wing 51 of spacer 48 of the post 4 downstream, in the traffic direction, from the one connected to end 64. End 66 is connected to spacer 48 of the downstream post 4 by the bolt engaging the higher of the two holes 52 in wing 51 of spacer 48 ( Figure 13) .
  • Top struts 63 are substantially parallel to the traffic lane plane, i.e. lie in a plane perpendicular to the axes of posts 4, and, together with chain 59 ( Figure 2) , rail 46 and spacers 48, define a truss effectively imparting resistance, elasticity and plasticity to the top portion of the guardrail.
  • the longitudinal impact component which tends to deform posts 4 in the traffic direction, causes top struts 63 to act as ties, making maximum use of the tensile strength of the steel.
  • guardrail 3 also comprises a further strut 67 ( Figures 1 and 3) hereinafter referred to as a bottom strut.
  • Each bottom strut 67 has a bent perforated end 68 (Figure 19) which is connected to base plate 15 by tie 18 in the hole 17 adjacent to bracket I 13. Another bent perforated end 69 of each bottom strut 67 is connected to wall 8 of the post 4 downstream, in the traffic direction, from the one connected to end 68.
  • a bolt engages the hole in end 69 and a hole 71 ( Figures 5 and 6) formed in wall 8 at substantially the same height as hole 62 connecting chain 59.
  • One bottom strut 67 is sufficient for each module 7, and may advantageously be located in the last span, in the traffic direction, of module 7.
  • Figure 3 lies substantially, and so strengthens each module 7, in a vertical plane.
  • the longitudinal impact component also causes bottom struts 67 to act as ties, making maximum use of the tensile strength of the steel .
  • Guardrail 3 also comprises a wheel rail indicated as a whole by 72 and defined by channel segments
  • each support 73 is defined by a segment of another channel, the core of which has two offset slots 74 ( Figure 3) engaged by two corresponding bolts for connecting support 73 to two corresponding holes 76 ( Figure 5) in wall 8 of post 4.
  • Slots 74 extend substantially vertically to allow * a certain amount of adjustment to the position of support 73.
  • Holes 76 are so located that the center line of wheel rail 72 is located at an off-ground height substantially half that of the center line of strip 5; and the length of support 73 is such as to keep the wings of the wheel rail 72 channel detached from arc-shaped portion 23 of plate 21.
  • Each of the two wings of the support 73 channel has a slot 77 extending parallel to wheel rail 72, and which is engaged by a bolt for connecting support 73 to a slot 78 in the corresponding wing of the wheel rail 72 channel; and the edge of support 73 adjacent to the core of the wheel rail 72 channel has a semicircular recess 79 for the purpose explained later on.
  • the shaped strip 5 segments of two adjacent modules 7 of guardrail 3 are connected to each other by a set of bolts 81 in end portions 82 - respective head and tail end portions in the traffic direction - of adjacent modules 7 ( Figure 12) .
  • the holes for bolts 81 are arranged in two columns at predetermined distances from the end edge of portion 82, but with two pairs of holes in one column located at a distance greater than said predetermined distance, as described in Italian Patent Application TO98A000044 filed by the present Applican .
  • the head and tail portions 82 of strips 5 of two adjacent modules 7 are advantageously superimposed at a post 4.
  • spacer 24 is provided with a plate 26" ( Figure 11) having bent edges 38 and 39 not projecting with respect to bent wing 33.
  • end portions 82 are superimposed smoothly in the traffic direction of the lane, i.e. the head end portion 82 - in the traffic direction of the lane - of one strip 5 segment is superimposed on the tail end portion of the downstream strip 5 segment, so that the overlaps of the two guardrails 3 on either side of the lane are specular.
  • fitting 83 ( Figures 3, 13, 14) having the same section as rail 46. More specifically, fitting 83 comprises a central wall 84, two flared walls 86, and two flanges 87, and is placed on the inside of two rail 46 segments, between which a gap of a few centimeters is left.
  • Fitting 83 and each end of a rail 46 segment are connected by a set of bolts 85, which connect the two central walls 84 and 47, and by a further two sets of bolts 90, which connect flared walls 86 and 49.
  • Fitting 83 also comprises a pair of slots 95, which replace holes 55 in wall 47 and provide for connecting respective spacer 48.
  • the outer surface of the two rail 46 segments of connected modules 7 is therefore smooth with no hazardous I steps .
  • each chain 58, 59 ( Figure 17) are connected by means of respective overlapping head and tail portions 88, each of which has a pair of slots 89 on either side of slot 60 for connection to the end posts of module 7.
  • portions 88 are superimposed smoothly in the traffic direction, so that these overlaps of the guardrails 3 on either side of the lane are also specular.
  • each of the wheel rail 72 channel segments has, in the traffic direction, a head end 91 and a tail end 92.
  • the tail end 92 has a longitudinal ridge 93 to reduce the core width of the channel, and which fits inside the semicircular recess 79 on support 73.
  • Tail end 92 is fitted inside the head end 91 of the upstream segment, in the traffic direction, by means of a bolt which engages the corresponding slots 78 formed in the wings of ends 91 and 92. As such, the wheel rail 72 segments are also overlapped smoothly in the traffic direction.
  • Guardrail 3 operates as follows.
  • the impact energy is absorbed mainly by shaped strip 5 and respective spacers 24; strip 5 first tends to move parallel to itself without bending post 4 ; brackets 12 and 13 , base plate 15 and ties 18 in turn limit rotation of post 4; top rail 46 opposes the tendency of the vehicle to overshoot guardrail 3, by decelerating and directing the vehicle downwards; and wheel rail 72 prevents the vehicle wheel from jamming beneath strip 5.
  • slot 20 creates a preferential bend region, which distends arc-shaped portion 23 of plate 21, so that arc-shaped portion 23 withdraws from the wings of wheel rail 72 and limits deformation of post 4, which, upon impact, may therefore undergo a very small amount of backward deformation, but without being knocked down.
  • brackets 12 and 13, base plate 15 and ties 18 obviously also limit rotation of post 4.
  • the tie-functioning arrangement of struts 63 and 67 provides for making maximum use of the tensile strength of the steel; and the symmetry of the right and left guardrails 3, and the smooth joints of the strip 5 rail 46 and wheel rail 72 segments prevent any damage which may be caused by steps in the overlapping segments .
  • guardrail 3 simplifies production and provides for preassembling modules 7 to further speed up on-site installation .
  • Top rail 46 is so sized and located as to enable guardrail 3 to retain heavy vehicles, even with a high center of gravity, and also to decelerate and direct light vehicles downwards; chains 58 and 59 provide for transmitting the action of struts 63 and 67 to a certain number of posts 4; and wheel rail 72 and respective supports 73 prevent light vehicles from jamming beneath strip 5.
  • each post 4 is deformed gradually and dissipates energy in the event of impact, while reinforcing brackets 12 and 13 strengthen the connection to base plate 15 ; post 4 , strip 5, rail 46 and wheel rail 72 as a whole are designed to provide for maximum ductility, plasticity and elasticity of the steel of all the components; and the geometry and use of Fe430B material for parts subject to impact are based on long-term statistical and dynamic tests to achieve maximum gradual dissipation of impact energy, and to reduce deformation and increase the resistance of the parts.
  • changes may be made to the guardrail as described herein without, however, departing from the scope of the accompanying Claims.
  • strip 5 may have other than three ridges, and/or the strip 5 segments may be connected by two columns of bolts 81 all the same distance from the end edge; walls 47 and 49 of rail 46 may be connected by ample curved portions, and the rail 46 segments may be overlapped smoothly like those of wheel rail 72; and struts 63 and 67 may have a different, e.g. L-shaped, section.
  • Wheel rail 72 may be dispensed with in the case of guardrails from which a lesser degree of impact control is required.
  • the spacing of posts 4 may be increased to 2.000 or 2.500 meters, so that each 4.000 or 4.500 meter long module 7 is connected to only three posts 4.
  • top strut 63 may be located between the first post 4 of module 7, in the traffic direction, and the middle post 4 of the same module 7, so that struts 63 and 67 are both located at alternate spans of guardrail 3 and alternate with each other.
  • top strut 63 and bottom strut 67 may be fitted to alternate modules .
  • each top strut 63 may be fitted by end 64 (Figure 18) to rear wing 10 of each post 4, and by end 66 to wing 33 ( Figure 9) of spacer 24 of the post 4 downstream, in the traffic direction, to the one fitted with end 64.
  • end 66 may be connected at hole 34, in wing 33, connecting the top groove 6 of strip 5.

Abstract

The guardrail (3) has a series of posts (4) spaced a predetermined distance apart; at least one shaped strip (5) with three ridges; a rail (46) located over the shaped strip (5) to withstand impact by heavy vehicles with a high center of gravity; and a wheel rail (72) to prevent the wheels of light vehicles from jamming beneath the shaped strip (5). Each post (4) is connected to the upstream post (4), in the traffic direction of the lane, by a horizontal top strut (63); the last post (4), in the traffic direction, of each module (7) is connected to the upstream post by a vertical bottom strut (67).

Description

SEMIRIGID, HIGH-IMPACT-ENERGY-CONTROL, HIGH-IMPACT- ENERGY-ABSORPTION GUARDRAIL, IN PARTICULAR FOR BRIDGES AND SIMILAR ROAD STRUCTURES
TECHNICAL FIELD
The present invention relates to a semirigid, high-impact-energy-control, high-impact-energy- absorption guardrail, in particular for bridges and similar road structures.
BACKGROUND ART
Guardrails of the above type are known in which one or more shaped strips, normally with two or three ridges and aligned vertically, are connected by spacers to a number of posts fitted to the edge of the structure. Upon impact, the posts of such guardrails undergo severe deformation resulting in a dangerous outward shift of the guardrail .
Guardrails have been proposed in which the top strip is strengthened by a rear rail acting as a tie.
The top strip, however, is not high enough to withstand impact by heavy-duty vehicles, and the rear strengthening rail fails to provide for effectively improving the rigidity of the strip.
Moreover, the posts of known guardrails are so fitted to the edge of the structure as to be extremely difficult and expensive to replace; and, for known guardrails to be fitted effectively to the structure and to deform upon impact, a fairly wide edge is* required, which is rarely available in the case of bridges, viaducts and the like.
Moreover, bridges and viaducts along modern main roads having separate lanes for each traffic direction are normally also divided into opposite traffic lanes; and, normally, identical guardrails are erected indifferently on the right or left of the structure, despite being subjected to impact by opposite sides of vehicles of different types and/or traveling at different speeds. As such, known guardrails are designed and sized to withstand impact in both directions, thus resulting in considerable waste in material . DISCLOSURE OF INVENTION
It is an object of the present invention to provide a guardrail of the above type, which provides for effectively retaining the vehicle and effectively withstanding impact by each side of the vehicle . According to the present invention, there is provided a semirigid, high- impact-energy-control, high- impact-energy-absorption guardrail comprising a number of posts located a predetermined distance apart; and at least one shaped strip for withstanding impact by a vehicle; said shaped strip being connected to said posts by corresponding spacers; characterized in that at least some of said posts are connected to the respective adjacent posts by first struts so oriented as to exert traction in the event of impact at an impact angle of less than 90°.
More specifically, the guardrail is particularly suitable for bridges and similar road structures, and comprises a rail located over said shaped strip, with the center line of the rail at an off-ground height at least twice that of the center line of said shaped strip, so as to withstand impact by heavy vehicles with a high center of gravity; said first struts being connected at said rail .
It is a further object of the invention to provide a guardrail designed to minimize transverse shift upon impact, and to enable replacement of the posts without damaging the structure . This further object is achieved by a semirigid guardrail wherein each post is fitted, with a 3- to 10- degree tilt inwards of the lane, by means of a base plate having at least two slots for engaging corresponding ties defined by studs on a portion of the structure.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred, non-limiting embodiment of the invention will be described by way of example with reference to the accompanying drawings, in which:
Figure 1 shows a front view of a semirigid guardrail in accordance with the invention;
Figure 2 shows a top plan view of the Figure 1 guardrail;
Figure 3 shows a larger-scale section alontø line III-III in Figure 1;
Figure 4 shows a larger-scale portion of Figure 2;
Figure 5 shows the Figure 3 section with parts removed;
Figure 6 shows a partially sectioned front view of Figure 5 ;
Figure 7 shows a section along line VII-VII in Figure 5 ; Figure 8 shows a partial, larger-scale section along line VIII-VIII in Figure 5;
Figure 9 shows a partial, larger-scale section along line IX-IX in Figure 3;
Figure 10 shows a spreadout view of a Figure 3 detail;
Figure 11 shows a variation of the Figure 10 detail;
Figure 12 shows a front view of a detail in Figure i; Figures 13 and 14 show larger-scale front and top plan views of a further detail in Figure 1;
Figure 15 shows a larger-scale detail of Figure 2; Figure 16 shows a larger-scale section along line XVI-XVI in Figure 15;
Figure 17 shows a front view of a detail in Figure 3; Figures 18 and 19 show views in perspective of a further two components of the guardrail.
BEST MODE FOR CARRYING OUT THE INVENTION
Number 1 in Figures 1 and 2 indicates as a whole a portion of a structure, e.g. a bridge or flyover, of a traffic lane in the direction of the arrow. On each side of the lane, the bridge has a curb 2 made of stone, reinforced concrete or iron, and fitted with a corresponding semirigid guardrail 3.
Each guardrail 3 is modular, and comprises a number of uprights or posts 4 equally spaced 1.333 m apart, which forms each span of the guardrail. Posts 4 support at least one known rail or shaped strip 5 having three ridges and two grooves 6 (Figure 3) ; strip 5 is defined by segments of at least 4.380 m in length, each of which is connected to four posts 4 (Figures 1 and 2), i.e. covers three spans between posts 4; and each segment of strip 5 defines a four-meter-long module 7 of guardrail 3.
Guardrail 3 also comprises a rail 46 located over strip 5; strip 5 and rail 46 are connected to posts 4 by corresponding spacers 24 and 48 as described later on; and posts 4, strip 5, rail 46 and spacers 24 and 48 are advantageously made of strong, quality steel, e.g. Fe430B to Italian standard UNI EN 10025.
According to the invention, the two guardrails 3 of respective curbs 2 of the lane differ from each other, so as to react, as explained later on, more effectively to vehicle impact at an angle of less than 90°. Figures 1 and 2 show the guardrail 3 of curb 2 on' the left-hand side of the lane.
To minimize the overall lateral size of guardrail 3, each post 4 (Figure 3) is fitted to curb 2 with the post axis tilted inwards of the lane by a given angle advantageously ranging between 3° and 10° and preferably of 7° . Post 4 is defined by a channel having a flat wall 8 crosswise to strip 5 and facing oncoming traffic. The post 4 channel also comprises a front wing 9 (Figures 5-8) ; and a rear wing 10 having a bent edge 11. Wings 9 and 10 are located on the downstream side of post 4 in the lane direction; the bottom end of post 4 is reinforced by two brackets 12 and 13 , each having a sloping edge with a strengthening ridge 14 ; bracket 12 is trapezoidal and welded to flat wall 8 of the post 4 channel ; and bracket 13 is in the form of an irregular pentagon, and is welded to the edge of front wing 9 and to the bent edge 11 of wing 10 of the channel .
Post 4 is connected at the desired angle to a rectangular base plate 15, fitted to curb 2, by welding the bottom edges of brackets 12 and 13 and the bottom edge of wing 10 of the channel to plate 15. Plate 15 comprises two slots 16 (Figure 4) located to the side of brackets 12 and 13 and aligned parallel to strip 5; and two holes 17 aligned transversely with slots 16, but offset longitudinally with respect to each other so that the hole 17 downstream in the traffic direction is • closer to the corresponding slot 16. The amount by which holes 17 are offset may advantageously equal half the distance between slots 16. Slots 16 and holes 17 are engaged by four ties 18
(Figure 3) defined by studs permanently embedded in curb 2 , so that plate 15 is fitted removably to curb 2 by screwing respective nuts to ties 18 with the interposition of respective plates. Ties 18 of slots 16 may be longer than those of holes 17.
A bottom portion of post 4, located between the bracket 13 connection and the connection of spacer 24 of strip 5, is strengthened by a reinforcing segment 19 such as to form a box portion of said bottom portion. More specifically, reinforcing segment 19 (Figure 8) is in the form of an L section, the wider wing of which is the same width as wing 10 and welded to wall 8, and the narrower wing of which is coplanar with and welded to bent edge 11. Front wing 9 of the post 4 channel has a slot 20
(Figure 6) extending axially along post 4, and at which wing 9 is fitted with a front strengthening member defined by a plate 21 comprising two end portions 22 welded to wing 9, and an arc-shaped central portion 23
(Figures 3 and 5) located at slot 20. Arc-shaped portion 23 extends about two-thirds of the total length of plate 21; the bottom portion 22 is about twice as long as the top portion 22; and slot 20 and plate 21 provide for a high degree of elasticity of the post" portion between brackets 12, "13 and spacer 24 of strip 5.
Spacer 24 provides for keeping strip 5 substantially parallel to post 4, and is defined by a substantially rectangular plate 26 (Figure 10) having a top and bottom side 27, 28 perpendicular to the axis of post 4, and a front and rear side 31, 29 parallel to the post axis. Side 29 is positioned substantially flush with wing 10 of post 4, while side 31 projects from post 4 and has two triangular openings 32.
Between the two openings 32, side 31 is bent 90° to form a wing 33 (Figure 9) for supporting strip 5 (Figure 3) with the center line at a height of about 700 mm. For which purpose, wing 33 has two holes 34 corresponding with the two grooves 6 of strip 5; and each groove 6 has horizontal-axis slots 36 (Figure 12) spaced the same distance apart as posts 4 to enable strip 5 to be fitted to wing 33 of each spacer 24 by means of two bolts with respective plates in between.
Along sides 27 and 28 (Figure 10) , plate 26 has two opposite U-bent edges 38 and 39 (Figures 3 and 9) , the bend lines of which are shown by dash lines in Figure 10. Bent edges 38 and 39 provide for strengthening spacer 24, and each have a projecting portion which fits inside the cavity of a respective outer ridge of strip 5. Finally, plate 26 is strengthened by a rib defined (by a T section 41, which is welded by the crosspiece to " plate 26, between the center line of side 29 and the center line of wing 33, and is therefore also perpendicular to the axis of post 4. Plate 26 has two slots 42 for receiving respective bolts 43, which also engage two holes 44 (Figure 5) , formed in wall 8 of post 4, with the interposition of slot-cover plates. The connection of spacers 24 to posts 4 provides for gradually dissipating impact energy and decelerating vehicles of any height, while enabling strip 5 to remain substantially parallel to itself.
The top rail 46 (Figure 3) is made of sheet metal shaped so as to have a cross section substantially in the form of the Greek letter omega (Ω) . Each segment of rail 46 is 3.950 m long and therefore sufficient for each module 7. Posts 4 are of such a height as to position the center line of rail 46 at an off-ground height of over twice that of the center line of shaped strip 5, so that rail 46 provides for withstanding impact by vehicles with a high center of gravity, such as industrial vehicles and buses . The center line of rail 46 may advantageously be located at a height of about 1.5 m. More specifically, rail 46 comprises a central wall 47 connected to each post 4 by a spacer 48 perpendicular to the axis of post 4; two walls 49 bent slightly less than 90° with respect to central wall 47 so as to be slightly flared; and two flanges 50 substantially parallel to central wall 47.
Spacer 48 is made of sheet metal bent into a C with a front wing 51 (Figures 13 and 14) , which is bent
90° and has two vertically aligned holes 52 corresponding with two holes 55 in wall 47 of rail 46.
At least one of holes 52 and the corresponding hole 55 are engaged by a bolt connecting spacer 48 to rail 46.
Spacer 48 also has two offset slots 53 (Figure 3) for receiving respective bolts 54, which also engage two corresponding holes 56 (Figure 5) , formed in wall 8 of post 4, via the interposition of perforated plates.
Such a connection provides for gradually dissipating the impact energy of vehicles with a high center of gravity, and also aids in decelerating the vehicle while maintaining rail 46 substantially parallel to itself.
Guardrail 3 also comprises two chains 58 and 59 (Figures 3 and 17) , each defined by segments of a flat section of the same length as module 7. Each chain 58, 59 has slots 60 for receiving two corresponding bolts, which also engage two corresponding holes 61, 62 (Figure 6) in rear wings 10 of posts 4. More specifically, hole 61 is located at spacer 48 (Figure 3) and provides for connecting chain 58, while hole 62 is located just beneath spacer 48 and provides for connecting chain 59.
Guardrail 3 also comprises a number of struts 63 indicated by dot-and-dash lines in Figure 2 and hereinafter referred to as top strutjs . Each top strut 63 has a bent perforated end 64 (Figure 18) located between bottom chain 59 and wing 10 of each post 4, and is connected to bottom chain 59 and wing 10 by the bolt engaging slot 60 in chain 59 and hole 62 in wing 10.
Another bent perforated end 66 of each top strut 63 is located between wall 47 of rail 46 and the bent wing 51 of spacer 48 of the post 4 downstream, in the traffic direction, from the one connected to end 64. End 66 is connected to spacer 48 of the downstream post 4 by the bolt engaging the higher of the two holes 52 in wing 51 of spacer 48 (Figure 13) .
Top struts 63 are substantially parallel to the traffic lane plane, i.e. lie in a plane perpendicular to the axes of posts 4, and, together with chain 59 (Figure 2) , rail 46 and spacers 48, define a truss effectively imparting resistance, elasticity and plasticity to the top portion of the guardrail. In the event of vehicle impact at an impact angle of less than 90°, the longitudinal impact component, which tends to deform posts 4 in the traffic direction, causes top struts 63 to act as ties, making maximum use of the tensile strength of the steel. For each module 7 , guardrail 3 also comprises a further strut 67 (Figures 1 and 3) hereinafter referred to as a bottom strut. Each bottom strut 67 has a bent perforated end 68 (Figure 19) which is connected to base plate 15 by tie 18 in the hole 17 adjacent to bracket I 13. Another bent perforated end 69 of each bottom strut 67 is connected to wall 8 of the post 4 downstream, in the traffic direction, from the one connected to end 68. For which purpose, a bolt engages the hole in end 69 and a hole 71 (Figures 5 and 6) formed in wall 8 at substantially the same height as hole 62 connecting chain 59. One bottom strut 67 is sufficient for each module 7, and may advantageously be located in the last span, in the traffic direction, of module 7.
The tilt of post 4 and the location of slots 16 in base plate 15 are such that each bottom strut 67
(Figure 3) lies substantially, and so strengthens each module 7, in a vertical plane. In the event of vehicle impact at an impact angle of less than 90°, the longitudinal impact component also causes bottom struts 67 to act as ties, making maximum use of the tensile strength of the steel .
Guardrail 3 also comprises a wheel rail indicated as a whole by 72 and defined by channel segments
(Figure 15) , each of which extends the whole length of module 7 and is connected to respective posts 4 by corresponding supports 73. More specifically, each support 73 is defined by a segment of another channel, the core of which has two offset slots 74 (Figure 3) engaged by two corresponding bolts for connecting support 73 to two corresponding holes 76 (Figure 5) in wall 8 of post 4.
Slots 74 extend substantially vertically to allow* a certain amount of adjustment to the position of support 73. Holes 76 are so located that the center line of wheel rail 72 is located at an off-ground height substantially half that of the center line of strip 5; and the length of support 73 is such as to keep the wings of the wheel rail 72 channel detached from arc-shaped portion 23 of plate 21.
Each of the two wings of the support 73 channel has a slot 77 extending parallel to wheel rail 72, and which is engaged by a bolt for connecting support 73 to a slot 78 in the corresponding wing of the wheel rail 72 channel; and the edge of support 73 adjacent to the core of the wheel rail 72 channel has a semicircular recess 79 for the purpose explained later on.
The shaped strip 5 segments of two adjacent modules 7 of guardrail 3 are connected to each other by a set of bolts 81 in end portions 82 - respective head and tail end portions in the traffic direction - of adjacent modules 7 (Figure 12) . The holes for bolts 81 are arranged in two columns at predetermined distances from the end edge of portion 82, but with two pairs of holes in one column located at a distance greater than said predetermined distance, as described in Italian Patent Application TO98A000044 filed by the present Applican .
The head and tail portions 82 of strips 5 of two adjacent modules 7 are advantageously superimposed at a post 4. In which case, to simplify replacement of a' strip 5 segment, spacer 24 is provided with a plate 26" (Figure 11) having bent edges 38 and 39 not projecting with respect to bent wing 33. To reduce damage in the event of vehicle impact, end portions 82 are superimposed smoothly in the traffic direction of the lane, i.e. the head end portion 82 - in the traffic direction of the lane - of one strip 5 segment is superimposed on the tail end portion of the downstream strip 5 segment, so that the overlaps of the two guardrails 3 on either side of the lane are specular.
The rail 46 segments of two adjacent modules 7, on the other hand, are connected to each other by a fitting 83 (Figures 3, 13, 14) having the same section as rail 46. More specifically, fitting 83 comprises a central wall 84, two flared walls 86, and two flanges 87, and is placed on the inside of two rail 46 segments, between which a gap of a few centimeters is left.
Fitting 83 and each end of a rail 46 segment are connected by a set of bolts 85, which connect the two central walls 84 and 47, and by a further two sets of bolts 90, which connect flared walls 86 and 49. Fitting 83 also comprises a pair of slots 95, which replace holes 55 in wall 47 and provide for connecting respective spacer 48. The outer surface of the two rail 46 segments of connected modules 7 is therefore smooth with no hazardous I steps .
The segments of each chain 58, 59 (Figure 17) are connected by means of respective overlapping head and tail portions 88, each of which has a pair of slots 89 on either side of slot 60 for connection to the end posts of module 7. Like the shaped strip 5 segments, portions 88 are superimposed smoothly in the traffic direction, so that these overlaps of the guardrails 3 on either side of the lane are also specular. Finally, each of the wheel rail 72 channel segments has, in the traffic direction, a head end 91 and a tail end 92. The tail end 92 has a longitudinal ridge 93 to reduce the core width of the channel, and which fits inside the semicircular recess 79 on support 73. Tail end 92 is fitted inside the head end 91 of the upstream segment, in the traffic direction, by means of a bolt which engages the corresponding slots 78 formed in the wings of ends 91 and 92. As such, the wheel rail 72 segments are also overlapped smoothly in the traffic direction.
Guardrail 3 operates as follows.
In the event of the right side of a light vehicle striking the right-side guardrail 3, or the left side of a light vehicle striking the left-side guardrail 3, with an impact angle of less than 90° with respect to the traffic direction of the lane, the impact energy is absorbed mainly by shaped strip 5 and respective spacers 24; strip 5 first tends to move parallel to itself without bending post 4 ; brackets 12 and 13 , base plate 15 and ties 18 in turn limit rotation of post 4; top rail 46 opposes the tendency of the vehicle to overshoot guardrail 3, by decelerating and directing the vehicle downwards; and wheel rail 72 prevents the vehicle wheel from jamming beneath strip 5.
In the event of impact by a heavy vehicle, impact energy is absorbed by both shaped strip 5 and top rail 46, which first move parallel to themselves. The height of posts 4, and hence the off-ground height of top rail 46, prevents the center of gravity of the vehicle from levering the vehicle over; the impact energy on post 4 is transmitted to the downstream posts 4 by the traction of top struts 63; and displacement and deformation of the top end of post 4 are transmitted to base plate 15 of the upstream post by the traction of bottom strut 67.
If displacement of strip 5 and rail 46 fails to absorb all the impact energy, posts 4 bend outwards. For which purpose, slot 20 creates a preferential bend region, which distends arc-shaped portion 23 of plate 21, so that arc-shaped portion 23 withdraws from the wings of wheel rail 72 and limits deformation of post 4, which, upon impact, may therefore undergo a very small amount of backward deformation, but without being knocked down. As in the previous case, brackets 12 and 13, base plate 15 and ties 18 obviously also limit rotation of post 4.
The advantages, as compared with known guardrails, of the guardrail according to the invention will be clear from the foregoing description. In particular, in the event of impact at an impact angle of less than 90°, the tie-functioning arrangement of struts 63 and 67 provides for making maximum use of the tensile strength of the steel; and the symmetry of the right and left guardrails 3, and the smooth joints of the strip 5 rail 46 and wheel rail 72 segments prevent any damage which may be caused by steps in the overlapping segments .
Moreover, the slight tilt of post 4 and the size of base plate 15 enable assembly to narrow curbs 2; ties 18 enable posts 4 to be fitted to curb 2 and removed with no damage to the structure, and also prevent damage to the structure in the event of impact; assembly of the guardrail components is far more straightforward and faster in every respect as compared with known guardrails; and the modular design of guardrail 3 simplifies production and provides for preassembling modules 7 to further speed up on-site installation .
Top rail 46 is so sized and located as to enable guardrail 3 to retain heavy vehicles, even with a high center of gravity, and also to decelerate and direct light vehicles downwards; chains 58 and 59 provide for transmitting the action of struts 63 and 67 to a certain number of posts 4; and wheel rail 72 and respective supports 73 prevent light vehicles from jamming beneath strip 5.
By virtue of front reinforcing plate 21, each post 4 is deformed gradually and dissipates energy in the event of impact, while reinforcing brackets 12 and 13 strengthen the connection to base plate 15 ; post 4 , strip 5, rail 46 and wheel rail 72 as a whole are designed to provide for maximum ductility, plasticity and elasticity of the steel of all the components; and the geometry and use of Fe430B material for parts subject to impact are based on long-term statistical and dynamic tests to achieve maximum gradual dissipation of impact energy, and to reduce deformation and increase the resistance of the parts. Clearly, changes may be made to the guardrail as described herein without, however, departing from the scope of the accompanying Claims. For example, strip 5 may have other than three ridges, and/or the strip 5 segments may be connected by two columns of bolts 81 all the same distance from the end edge; walls 47 and 49 of rail 46 may be connected by ample curved portions, and the rail 46 segments may be overlapped smoothly like those of wheel rail 72; and struts 63 and 67 may have a different, e.g. L-shaped, section.
Wheel rail 72 may be dispensed with in the case of guardrails from which a lesser degree of impact control is required. The spacing of posts 4 may be increased to 2.000 or 2.500 meters, so that each 4.000 or 4.500 meter long module 7 is connected to only three posts 4. In which case, top strut 63 may be located between the first post 4 of module 7, in the traffic direction, and the middle post 4 of the same module 7, so that struts 63 and 67 are both located at alternate spans of guardrail 3 and alternate with each other. Alternatively, top strut 63 and bottom strut 67 may be fitted to alternate modules .
In an alternative embodiment, rail 46 may be eliminated, and each top strut 63 may be fitted by end 64 (Figure 18) to rear wing 10 of each post 4, and by end 66 to wing 33 (Figure 9) of spacer 24 of the post 4 downstream, in the traffic direction, to the one fitted with end 64. In particular, end 66 may be connected at hole 34, in wing 33, connecting the top groove 6 of strip 5.

Claims

1) A semirigid, high-impact-energy-control, high- impact-energy-absorption guardrail comprising a number of posts (4) located a predetermined distance apart; and at least one shaped strip (5) for withstanding impact by a vehicle; said shaped strip (5) being connected to said posts (4) by corresponding spacers (24) ; characterized in that at least some of said posts (4) are connected to the respective adjacent posts (4) by first struts (63) so oriented as to exert traction in the event of said impact at an impact angle of less than 90° .
2) A guardrail as claimed in Claim 1, characterized in that the top end of each of at least some of said posts (4) is fitted with a second strut (67) so oriented as to exert traction in the event of said impact .
3) A guardrail as claimed in Claim 1 or 2 , in particular for bridges and similar road structures, characterized by comprising a rail (46) located over said shaped strip (5) with the center line of the rail at an off-ground height at least twice that of the center line of said shaped strip (5) , so as to withstand impact by heavy vehicles with a high center of gravity; said first struts (63) being connected at said rail (46) .
4) A guardrail as claimed in one of the foregoing Claims, characterized in that said posts (4) are also fitted with a wheel rail (72) , the center line of which is located at an off-ground height substantially equal to half the height of the center line of said shaped strip (5) .
5) A guardrail as claimed in ohe of the foregoing Claims, characterized in that said post (4) is connected to a base plate (15) fitted removably to a portion (2) of the structure; said post (4) being connected to said base plate (15) at a 3- to 10-degree tilt inwards of the lane .
6) A guardrail as claimed in Claim 3, characterized in that said shaped strip (5) , said rail (46) and said post (4) are made of high-strength sheet metal .
7) A guardrail as claimed in one of the foregoing Claims, characterized in that each of said first struts (63) lies in a substantially horizontal plane and slopes towards the center line in the traffic direction of the lane.
8) A guardrail as claimed in Claims 3 and 7, characterized in that said rail (46) is connected to said posts (4) by respective spacers (48) ; said posts (4) also being connected by at least one chain (59) opposite said rail (46) .
9) A guardrail as claimed in Claim 8, characterized in that each of said first struts (63) has a first end (64) connected between said post and said chain (59) , and a second end (66) connected between said rail (46) and the respective spacer (48) of the downstream post (4) in said traffic direction.
10) A guardrail as claimed in Claim 8 or 9, characterized in that said rail (46) is made of sheet metal formed into a shape substantially similar to the Greek letter omega (Ω) with the base facing said post (4) .
11) A guardrail as claimed in Claim 10, characterized in that said rail (46) comprises a substantially vertical central wall (47) connected to the respective spacers (48) of a group of posts (4) ; two substantially horizontal, slightly flared walls (49) ; and two flanges (50) substantially parallel to said central wall (47) .
12) A guardrail as claimed in Claim 2 and one of Claims 3 to 11, characterized in that said second strut (67) lies in a substantially vertical plane, and has a first end (68) connected to said base plate (15) of one post (4) , and a second end (69) connected at said top end of the downstream post (4) in the traffic direction of the lane .
13) A guardrail as claimed in Claim 12, characterized in that said second end of said second strut (67) is also located at said chain (59) ; said posts (4) also being connected by a second chain (58) located over the first end (64) of said first strut (63) .
14) A guardrail as claimed in one of Claims 8 to 13, characterized in that said post (4) is defined by a channel comprising a flat wall (8) and two wings (9, 10) ; the spacer (48) of said rail (46) being defined by a channel fitted to said flat wall (8) and having a bent wing (51) fitted to said central wall (47) of said rail (46) .
15) A guardrail as claimed in Claim 14, characterized in that said chains (58, 59) are connected to a rear wing (10) of the channel of the post (4) ; said second end (69) of said second strut (67) being connected to said flat wall (8) .
16) A guardrail as claimed in Claim 14 or 15, characterized in that said wheel rail (72) is defined by a channel, the wings of which are connected to two wings of a C-section support (73) ; said support (73) being fitted to said flat wall (8) of the post (4) .
17) A guardrail as claimed in Claim 5 and one of Claims 8 to 16, characterized in that said base plate (15) has at least two slots (16) engaged by corresponding ties (18) defined by studs in a portion (2) of the structure.
18) A guardrail as claimed in Claim 17, characterized in that said slots (16) are aligned along the axis of said lane; said base plate (15) also having two holes (17) aligned transversely with said slots (16) but offset longitudinally with respect to each other; said holes (17) being engaged by a further two ties (18) in said portion (2) of the structure.
19) A guardrail as claimed in Claim 14 and one of Claims 16 to 18, characterized in that a bottom portion of said post (4) is reinforced by a reinforcing segment (19) such as to form a box-section portion; a pair of brackets (12, 13) being fitted between said base plate' (15) and said bottom portion.
20) A guardrail as claimed in Claim 19, characterized in that said brackets (12, 13) are parallel; one of said brackets (12, 13) being welded to said flat wall (8) , and the other of said brackets (12, 13) being welded partly to the edges of said wings (9, 10) and partly to a wall of said reinforcing segment
(19) . 21) A guardrail as claimed in Claim 19 or 20, characterized in that, at a connecting portion for connection of said support (73) , a front wing (9) of said post (4) has a slot (20) extending axially and for making said connecting portion elastic; said front wing (9) also having a front reinforcing member (21) for limiting elastic deformation of said post (4) .
22) A guardrail as claimed in Claim 21, characterized in that said front reinforcing member is defined by a plate (21) having two flat end portions (22) welded to said front wing (9) of said post (4) , and a curved central portion (23) covering said slot
(20) of said front wing (9) .
23) A guardrail as claimed in Claim 22, characterized in that said curved central portion (23) is substantially half the length of said plate (21) ; and in that the bottom portion (22) of said two flat end portions (22) is at least twice the length of the top portion (22) .
24) A guardrail as claimed in Claim 23, characterized in that the length of said support (73) is so selected as to prevent said wheel rail (72) from engaging said curved central portion (23) in the event of impact by a light vehicle .
25) A guardrail as claimed in Claim 14 and one of Claims 16 to 24, characterized in that each spacer (24) of said shaped strip (5) is connected to said post (4) by bolts (43) engaging corresponding slots (42) in the spacer (24) and holes (44) in said flat wall (8) ; said slots (42) being perpendicular to the axis of said post
(4) to permit movement of said shaped strip (5) parallel to itself to gradually dissipate the impact energy of the vehicle . 26) A guardrail as claimed in Claim 25, wherein said shaped strip (5) is of the type having three ridges separated by two grooves (6) ; characterized in that said spacer (24) of said shaped strip (5) is defined by a substantially rectangular plate (26, 26') having said slots (42) ; said rectangular plate (26, 26') having a bent wing (33) fitted to said grooves (6).
27) A guardrail as claimed in Claim 26, characterized in that said rectangular plate (26, 26') is reinforced by a central rib (41) substantially perpendicular to said post (4) ; some of said slots (42) being located above and some others below said rib (41) .
28) A guardrail as claimed in Claim 26 or 27, characterized in that said rectangular plate (26, 26') has two edges (38, 39) bent into a U and perpendicular to said post (4); said edges (38, 39) having each a portion projecting with respect to said bent wing (33) to support two of said ridges from behind.
29) A guardrail as claimed in Claim 27 or 28, characterized in that said shaped strip (5) is defined by a series of segments connected to one another by bolts (81) at an overlap portion (82) of each two adjacent segments; said overlap portion (82) being located at one of said posts (4) ; and the guardrail portion comprising a shaped strip (5) segment defining a guardrail module (7) . 30) A guardrail as claimed in Claim 29, characterized in that said overlap portion (82) is formed by superimposing the head end, in the traffic direction of the lane, of one segment on the tail end of the downstream segment in said traffic direction. 31) A guardrail as claimed in Claims 10 and 30, characterized in that said rail, said wheel rail (72) and said chains (58, 59) are defined by respective segments of the same length as said module (7) , and the joints of which are made at end posts (4) of said module (7) .
32) A guardrail as claimed in Claim 31, characterized in that each joint of said wheel rail (72) is formed by superimposing a head end, in the traffic direction of the lane, of one segment on a tail end of the downstream segment in said traffic direction.
33) A guardrail as claimed in Claim 31 or 32, characterized in that each joint of said rail (46) is formed by means of a fitting (83) having a section similar to that of said rail (46) and located on the inside of two adjacent ends of two adjacent segments of said rail (46) . 34) A guardrail as claimed in one of Claims 29 to 33, characterized in that each module (7) comprises three spans between said posts (4) ; said first strut (63) being located between each of said posts (4) and one of the adjacent posts (4) ; and said second strut (67) being located, in each module (7) , between the end post (4) , in the traffic direction, and the upstream post (4) .
35) A guardrail as claimed in one of Claims 29 to 33, characterized in that each module (7) comprises two spans between said posts (4) ; said first strut (63) being located, in each module (7) , between the first of said posts (4) , in the traffic direction, and the middle post (4) in the module (7) ; and said second strut (67) being located, in each module (7) , between the end post (4) , in the traffic direction, and the preceding post (4) .
36) A guardrail as claimed in Claim 1 or 2 , wherein said shaped strip (5) is of the type having three ridges separated by two grooves (6) ; said shaped strip (5) being connected to each of said posts (4) by a respective spacer (24) having a member (33) fitted to said grooves (6) ; characterized in that said first strut (63) is connected between a wing (10) of one of said posts (4) , and said member (33) of the spacer (24) of the downstream post (4) in the traffic direction, at one of said grooves (6) .
PCT/IT1999/000346 1998-10-30 1999-10-29 Semirigid, high-impact-energy-control, high-impact-energy-absorption guardrail, in particular for bridges and similar road structures WO2000026474A1 (en)

Priority Applications (1)

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AU10761/00A AU1076100A (en) 1998-10-30 1999-10-29 Semirigid, high-impact-energy-control, high-impact-energy-absorption guardrail, in particular for bridges and similar road structures

Applications Claiming Priority (2)

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IT1998TO000920 IT1305149B1 (en) 1998-10-30 1998-10-30 SEMI-RIGID ROAD BARRIER WITH HIGH CAPACITY OF CONTAINMENT AND IMPACT ABSORPTION, IN PARTICULAR FOR BRIDGES AND SIMILAR
ITTO98A000920 1998-10-30

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WO1996023933A1 (en) * 1995-02-01 1996-08-08 Pascal Rambaud Roadside crash barrier with a shock-absorbing device

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1167628A2 (en) * 2000-06-26 2002-01-02 Renton Productions Limited A road crash barrier
EP1167628A3 (en) * 2000-06-26 2003-10-29 Renton Productions Limited A road crash barrier
EP1566486A1 (en) * 2004-02-23 2005-08-24 Profil R Retainer for road guard rail
EP2982799A1 (en) * 2014-08-08 2016-02-10 voestalpine Krems Finaltechnik GmbH Vehicle retention system
EP2982800A1 (en) * 2014-08-08 2016-02-10 voestalpine Krems Finaltechnik GmbH Vehicle retention system
EP3121337A1 (en) * 2014-08-08 2017-01-25 voestalpine Krems Finaltechnik GmbH Vehicle retention system
EP3121336A1 (en) * 2015-07-24 2017-01-25 voestalpine Krems Finaltechnik GmbH Vehicle retention system
CN106836078A (en) * 2017-03-24 2017-06-13 温州泓呈祥科技有限公司 The movable type that a kind of municipal road engineering is used prevents wearing guardrail
CN109083051A (en) * 2017-03-24 2018-12-25 温州泓呈祥科技有限公司 A kind of anti-campus guardrail worn
CN109083051B (en) * 2017-03-24 2020-10-30 杭州富彩包装制品有限公司 Prevent campus guardrail of wearing

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IT1305149B1 (en) 2001-04-10
ITTO980920A1 (en) 2000-04-30
AU1076100A (en) 2000-05-22

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