Patent Grant
7220077
1. Field of the Invention
This invention relates to traffic noise barriers. More specifically, this invention relates to a crashworthy traffic noise barrier system for bridge rails and other longitudinal barriers.
2. Description of the Related Art
Traffic noise barrier walls serve to shield otherwise quiet areas from noise caused by automotive, railway, aircraft, marine, or pedestrian traffic. A typical traffic noise barrier wall is from about 4 to 24 feet in height and runs continuously alongside a selected section of a roadway, railway, aircraft runway, waterway, parking lot, walkway, and the like.
One common design of a traffic noise barrier wall includes a plurality of panels of wood or concrete supported by vertically mounted posts. Examples of such noise barrier walls are found in U.S. Pat. Nos. 5,713,170 and 5,537,788, both issued to Elmore et al. Noise barrier walls of this type are suitably sturdy and effective in reducing highway noise; however, such noise barrier walls are usually not designed for vehicle impact. As a result, these noise barriers are located many feet (e.g., 40 feet) from the normal path of traffic. Problematically, space constraints often require that noise barriers be located closer to the path of traffic. One example is when a noise barrier is required on a bridge.
Where space constraints exist, it is not uncommon for noise barriers to be mounted on top of a crashworthy traffic barrier. One example of such an arrangement is found in U.S. Pat. No. 4,214,411 issued to Pickett, wherein panels of transparent material are secured between beams mounted on top of a roadside barrier. The transparent panels are effective in providing travelers on the traffic path with a view outside the roadway. However, vehicles impacting the otherwise crashworthy traffic barrier may also strike the noise barrier, creating potential hazards to the impacting vehicle and nearby pedestrians.
The U.S. Federal Highway Administration (FHWA) requires all longitudinal barriers used on the National Highway System (NHS) to be crashworthy and to qualify as such according to the testing and acceptance guidelines of the National Cooperative Highway Research Program (NCHRP) Report No. 350, which is incorporated by reference herein in its entirety. Under NCHRP Report No. 350, longitudinal barriers include any device whose primary functions are to prevent vehicular penetration and to safely redirect an errant vehicle away from a hazard outside the normal path of the vehicle (e.g., outside the roadway). Longitudinal barriers include, for example, roadside barriers, median barriers, and bridge rails. For longitudinal barriers, NCHRP Report No. 350 defines six test levels, each of which prescribe test conditions appropriate for a range of highway types, traffic volumes, and other parameters. Test Level 1 (TL-1) and Test Level 2 (TL-2) are intended for low-speed and/or low-volume roads, while Test Level 3 (TL-3) through Test Level 6 (TL-6) are intended for high-speed facilities with increasingly higher traffic volumes. TL-1, TL-2, and TL-3 require redirection of an 820-kg car impacting a barrier at 20 degrees, and a 2,000-kg pickup truck impacting a barrier at 25 degrees, at speeds of 50 km/h, 70 km/h, and 100 km/h, respectively. TL-4 adds an 8,000-kg single-unit truck at 15 degrees and 80 km/h to the TL-3 matrix; TL-5 substitutes a 36,000-kg tractor/van trailer for the single-unit truck. TL-6 substitutes a 36,000-kg tractor/tank trailer. Thus, to be used on the NHS, a longitudinal barrier must be accepted by the FHWA as meeting one or more test levels of NCHRP 350. Such acceptance is typically indicated in a letter from the FHWA to the manufacturer of the longitudinal barrier or in a published memo from the FHWA.
Although NCHRP Report No. 350 offers guidance for the safety performance evaluation of longitudinal and other traffic barriers, it offers no guidance toward the evaluation of attachments on or near these barriers. Some guidance toward the evaluation of barrier attachments to barriers is provided in a technical paper entitled “Guidelines for Attachments to Bridge Rails and Median Barriers” by Keller et al. Using the Test Levels outlined in NCHRP Report No. 350, Keller et al. identify a “Zone of Intrusion” (ZOI) for a wide variety of traffic barriers, including sloped-face concrete parapets (e.g., New Jersey, Single Slope, F-shape, and open concrete rail), vertical-faced concrete parapets (e.g., vertical wall and open concrete rail), steel corrugated rails (e.g., W-beam and thrie beam), steel tubular rails, steel tubular rails on curbs, combination concrete and steel tube railings, and timber bridge rails. The ZOI represents an envelope around the barrier into which various vehicular components intrude upon the vehicle's impact with the barrier.
For noise barriers and similar attachments, referred to by Keller et al. as “continuous attachments”, Keller et al. provide various design considerations that allow such attachments to be placed in the ZOI. One suggestion is to use attachments that will breakaway, allowing the system to deflect upon impact by a vehicle. Where non-breakaway attachments are used, Keller et al. suggest that the design take into account the snag potential of the attachment. Snagging is when a portion of a vehicle engages a vertical element, such as a post, causing deceleration of the vehicle. In addition to snagging concerns, Keller et al. suggest that the potential implications of debris from impacts on these systems be considered because debris associated with the attachment may fall on traffic and/or pedestrians around or below the barrier. Keller et al. also suggest that vehicle occupant compartment intrusion and deformation be considered. Occupant compartment intrusion and deformation is a concern for traffic barrier attachments under two scenarios: (1) a vehicle component is driven into the occupant compartment due to impact with the attachment; or (2) the attachment itself intrudes into or deforms the occupant compartment. While Keller et al. provide various guidelines for the design of barrier attachments, Keller et al. fail to provide a design for a traffic noise barrier wall that would meet their guidelines.
Thus, there is a need for a traffic noise barrier wall for use where space constraints require the noise barrier wall to be located near a selected section of a roadway, railway, aircraft runway, waterway, parking lot, walkway, and the like, and which will prevent vehicle deceleration due to snagging, will reduce or eliminate occupant compartment intrusion and deformation, and which will reduce or eliminate falling debris concerns.
The above-described and other needs are met by a traffic noise barrier system for use alongside a path of traffic. The traffic noise barrier system comprises a longitudinal barrier extending substantially parallel to the path of traffic, and a traffic noise barrier wall supported by the longitudinal barrier. The traffic noise barrier wall includes: a plurality of upstanding posts attached to the traffic noise barrier wall; a plurality of panels supported by the plurality of upstanding posts; and at least one longitudinal beam extending across the plurality of upstanding posts for redirecting a portion of an errant vehicle away from the plurality of panels. The at least one longitudinal beam may include a first longitudinal beam spaced above the longitudinal barrier and disposed between the path of traffic and the plurality of panels, and a second longitudinal beam spaced above the first longitudinal beam and disposed between the path of traffic and the plurality of panels.
The panels may be disposed between each pair of adjacent posts. One or more of the panels may be transparent, and one or more of the panels may be reinforced with plastic bands, plastic threads, or a plastic net. The plastic threads may be high-contrast plastic threads, the high-contrast plastic threads having sufficient contrast to be recognized by birds flying in the vicinity of the panel and causing no substantial impairment of the overall transparency of the panel. Each panel in the plurality of panels may have a rigid frame disposed around at least a portion of its perimeter.
A rear support beam may be disposed on an opposite side of the panel from the first longitudinal beam, and a front support beam may be attached to the first longitudinal beam, between the first longitudinal beam and the panel Resilient members may be disposed between the front support beam and the panel and between the rear support beam and the panel. The longitudinal beam may be formed from a plurality of axially aligned sections.
A horizontal centerline of the first longitudinal beam is preferably spaced a distance between about 32 inches to about 44 inches above a terrain surface, and more preferably at 38 inches above the terrain surface. A horizontal centerline of the second longitudinal beam is preferably spaced a distance between about 44 inches to about 74 inches above the terrain surface, and more preferably 60 inches above the terrain surface. The longitudinal barrier may be qualified under National Cooperative Highway Research Program Report No. 350 Test Level 3.
In another embodiment, a third longitudinal beam is disposed between the path of traffic and the plurality of panels. The third longitudinal beam extends across the plurality of upstanding posts and is spaced above the second longitudinal beam. A horizontal centerline of the third longitudinal beam is preferably spaced a distance between about 100 inches to about 154 inches above the terrain surface, and more preferably about 128 inches above the terrain surface. The longitudinal barrier may be qualified under National Cooperative Highway Research Program Report No. 350 Test Level 4. In one embodiment, the longitudinal barrier has a height greater than or equal to 40 inches above the terrain surface and the first longitudinal beam is omitted.
Each of the upstanding posts may have a flange extending along substantially an entire height of the upstanding post. The flange extends generally parallel to the panel and forms a gap between opposing, generally parallel surfaces of the flange and the panel. Preferably, the gap is less than or equal to about ½ inch. In one embodiment, an anti-intrusion wedge is disposed within the gap.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the invention will be apparent from the description and drawings, and from the claims.
The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings wherein like elements are numbered alike, and in which:
Referring to
The traffic noise barrier wall 16 includes spaced-apart, upstanding posts 24 having panels 26 extending between each pair of posts 24. In the embodiment shown, one panel 26 is disposed between each pair of posts 24, however, it is contemplated that one or more panels 26 may be disposed between each pair of posts 24. The noise barrier wall 16 has a height above a terrain surface 28 of the path of traffic 12 that is appropriate for the particular application of the wall 16. For example, the height of the noise barrier wall 16 may be from about 4 to 18 feet, depending on the noise abatement requirements of the wall 16.
Each panel 26 is made from an acoustically absorptive and/or reflective material that is appropriate for the individual application of the traffic noise barrier wall 16. For example, the panels 26 may be made of a transparent material where it is desired that travelers on the path of traffic 12 have a view through the wall 16. One example of a preferred transparent material for use as a panel 26 is PARAGLAS SOUNDSTOP® Noise Barrier Sheet commercially available from CYRO Industries, 100 Enterprise Drive, Rockaway, N.J. Where transparency is not desired, other materials such as wood, steel, opaque acrylic, plastic, and the like, may be used. The panel 26 may be corrugated for added strength.
Referring to
Referring to
Where the panels 26 include plastic threads 27, these threads 27 may be high-contrast so that they can be recognized by birds flying in the vicinity of the panel while causing no substantial impairment of the overall transparency of the panel 26, as described in U.S. Pat. No. 5,372,866 issued Dec. 13, 1994 to Oberlander et al., which is incorporated by reference herein in its entirety. The term “high contrast”, as used herein, refers to plastic which has a transmission ratio between 0 and 65% (measured according to DIN 5033 (colorimetry) and 5036 (radiometric and photometric properties of materials)). Preferably, the material or the actual plastic thread 27 has a transmission ratio of 0 to 30%, more particularly 0 to 10%. A transmission ratio of about 0% is particularly advantageous. To obtain contrast also, the plastic thread 27 must stand out from the background, e.g., by having a different color. Metal-coated threads are unsuitable for this purpose if, for example, they reflect the sky in front of the panel against the sky behind the panel or give undesired reflexes or reflections, e.g. of the sun. It is advantageous to use dark threads, particularly black threads. Owing to the high-contrast of the threads, flying birds can recognize the transparent panel 26 as an obstacle before they fly into it, and while they are a few meters away, and can fly around the panel 26.
In particularly advantageous embodiments, the plastic threads 27 are 1 mm to 5 mm thick. More particularly the thickness range from 1.8 to 3.0 mm, preferably 2.0 to 2.5 mm, has been found particularly advantageous with regard to the required properties, i.e. easy insertion into the panel 26, sufficient strength in the event of a fracture, sufficient visibility to birds and no substantial impairment of the overall transparency of the panel 26.
The threads 27 in the panel 26 may extend horizontally, since the panels 26 are clamped at their sides; in that case the cohesion in the event of a fracture is particularly advantageous. The threads 27 may be laid parallel to one another. If desired or necessary, two layers of threads 27 can be incorporated in the panel 26 and will then preferably extend in two directions, an angle of 90° between threads 27 of different layers being particularly advantageous.
Usually, the distance between neighboring threads 27 is not greater than 100 mm, since greater distances markedly decreases the protection of birds or the prevention of fragmentation. Preferably, the distance between threads 27 is up to 50 mm, particularly when the threads 27 are horizontal, since birds appear to recognize horizontal obstacles less easily than vertical obstacles.
The surface density of the threads 27, i.e. the percentage of the surface of the entire panel 26 which is covered by the threads 27 (the surface density), is usually from about 2.5 to about 25%. Preferably, particularly in the case of horizontal threads 27, the surface density is at least about 5%, particularly advantageously about 6 to about 10%. In the case of vertical threads 27, the surface density can be slightly less, so that, in this case, the advantageous range is from 5 to 8%. Below this surface density, the bird-protecting effect is rapidly lost, whereas above these values the threads 27 remain visible at a greater distance and detract from the appearance, i.e. the advantageous transparency of the plastic panel 26 is largely wasted.
Typical panel 26 thicknesses are preferably about 4 to about 40 millimeters, and more preferably 12 to 25 mm. The panels 26 are usually manufactured in sizes of 2×2.5 meters to 2×5 meters. Larger or smaller sizes are possible for special uses.
The panels 26 are usually substantially transparent, preferably colorless or slightly tinted, e.g. smoky brown. Colorless transparent plastic panels 26 usually have a transmission ratio of at least 70%. A ratio of about 90 to about 95% is advantageous. Tinted embodiments usually have a transmission ratio of about 45 to about 75%, for example between about 50 and about 60%. The absorption of the threads 27 and of the tinted panel 26 is cumulative, so that the threads 27 are additionally recognizable as high-contrast elements.
In the embodiments of
Extending across the posts 24 are one or more longitudinal beams 32, 34 and 36. The longitudinal beams 32, 34 and 36 extend generally parallel to the top surface 20 of the longitudinal barrier 14 and generally perpendicular to the upstanding posts 24. In the embodiment shown, the posts 24 are formed from steel I-beams and longitudinal beams 32 are formed from steel tubes, respectively. It will be appreciated, however, that other rigid materials or structures may also be used. For example, the beams 32 or posts 24 may be formed from other metals (e.g., aluminum), fiberglass, and the like, and may be formed from a composite of materials. The beams 32 or posts 24 may be of any convenient cross sectional shape, such as for example: rounded (e.g., oval, ovoid, or round), I-beams, H-beams, channel beams, substantially flat, polygonal (e.g., triangular, quadrilateral (e.g., square, rectangular), pentagonal, hexagonal, heptagonal, octagonal, etc.).
The longitudinal beams 32, 34 and 36 are configured to redirect portions of an errant vehicle that may intrude into the area above the top surface 20 of the longitudinal barrier away from the panels 26. The longitudinal beams 32, 34, and 36 redirect energy of the errant vehicle away from the panels 26 such that the panels 26 and any fragments of the panels, remain attached to the traffic noise barrier wall 16. As shown in
The heights of y1, y2 and y3 are selected so that the corresponding longitudinal beams 32, 34 and 36 will impact different portions of an errant vehicle intruding into the area above the top surface 20 of the longitudinal barrier. Beam 32 is positioned at the height y1 to contact the lower portion (e.g., hood and upper fender) of the vehicle (e.g., a single-unit truck for TL-4 and a ¾ ton pickup truck for TL-3), beam 34 is positioned at the height y2 to contact the occupant compartment of the vehicle, and beam 36 is positioned at y3 to contact a box portion of a vehicle such as a single-unit truck. Where the height of the traffic noise barrier wall 16 is less than that required to achieve this spacing (e.g., less than about 100 inches), the distances y1 and y2 are preferably maintained within the ranges provided, and the third beam 36 is placed at or near the top of the noise barrier wall 16.
Referring to
In any case, the force F and deflection δ to which the one or more beams (e.g., 32, 34, and/or 36) are designed are chosen to ensure that the longitudinal beams withstand an impact of 55 kips, which is typical of a collision caused by an 8000 kg single unit truck striking at an angle of 15 degrees relative to a line parallel to the barrier. Withstanding a collision with an 8000 kg single unit truck is a requirement of NCHRP Report 350 Test Level 4. It is contemplated that the one or more longitudinal beams may be of any shape, configuration or material that meets this design requirement. It is also contemplated that the beams 32, 34, 36 could be replaced with multiple beams in approximately the same locations so long as, together, they meet the same requirements. As previously noted, each beam 32, 34, 36 is designed to deflect either a certain part of a vehicle or a certain type of vehicle. For instance, the first beam 32 is designed to contact the lower portion (e.g., hood and upper fender) of a single-unit box truck, the second beam 34 is designed to contact the occupant compartment of the single-unit box truck, and the third beam 36 is designed to capture the top portion of the container of the single-unit box truck. This then dictates the height of the beams 32, 34, 36 and load capability that the beams 32, 34, and 36 must withstand. It is also contemplated that different forces F and deflections δ can be incorporated into the design to meet other test criteria.
Also in applications requiring the system 10 to be qualified under Test Level 4 of the NCHRP Report No. 350, the upstanding posts 24 are preferably designed to withstand a load of 55 kips, applied as 25 kips on the first beam 32 and 15 kips each on the second and third beams 34, 36, without separating from the longitudinal barrier 14 and without fracturing the upstanding posts 24.
In applications requiring the system 10 to be qualified under Test Level 3 of the NCHRP Report No. 350, it has been determined that only the first and second beams 32 and 34 are needed and the third beam 36, may be removed. It has also been determined that in applications requiring the system 10 be qualified under Test Level 3 of the NCHRP Report No. 350 and where the beams 32 and 34 are formed from steel, the first longitudinal beam 32 may be sized to deflect no more than about ½ inch under a force of 10 kips applied in a direction away from the path of traffic 12 and normal to the first longitudinal beam 32 at a point mid span (L/2) between two adjacent upstanding posts 24; and the second longitudinal beam 34 may be sized to deflect no more than about ½ inch under a force of 10 kips applied in a direction away from the path of traffic 12 and normal to the second longitudinal beam 34 at a point mid span (L/2) between the two adjacent upstanding posts 24. It has been determined that by minimizing the deflection δ under these forces, the potential for breakage of the panels 26 and the potential for the errant vehicle snagging a post 24 are reduced. While no more than about ½ inch deflection δ for each of the beams 32 and 34 under their respective loads is preferred, it is believed that deflections δ of between about ¼ inch to about 6 inches under these loads are acceptable.
In any case, the force F and deflection δ to which the one or more beams (e.g., 32 and/or 34) are designed are chosen to ensure that the longitudinal beams withstand an impact of 10 kips, which is typical of a collision caused by ¾ ton pickup truck having a weight of 2000 kg at an angle of 25 degrees relative to a line parallel to the barrier. Withstanding a collision with a ¾ ton pickup truck having a weight of 2000 kg is a requirement of NCHRP Report 350 Test Level 3. It is contemplated that the one or more longitudinal beams may be of any shape, configuration or material that meets this design requirement. It is also contemplated that the beams 32, 34 could be replaced with multiple beams in approximately the same locations so long as, together, they meet the same requirements. As previously noted, each beam 32, 34 is designed to deflect either a certain part of a vehicle or a certain type of vehicle. For instance, the first beam 32 is designed to contact the lower portion (e.g., hood and upper fender) of a ¾ ton pickup truck, and the second beam 34 is designed to contact the occupant compartment of the ¾ ton pickup truck. This then dictates the height of the beams 32, 34 and load capability that the beams 32, 34 must withstand. It is also contemplated that different forces F and deflections δ can be incorporated into the design to meet other test criteria.
Also in applications requiring the system 10 to be qualified under Test Level 3 of the NCHRP Report No. 350, the upstanding posts 24 are preferably designed to withstand a load of 10 kips, without separating from the longitudinal barrier 14 and without fracturing the upstanding posts 24.
Referring again to
Referring to
As also shown in
Referring to
As shown in
In addition to minimizing the gap formed between the opposing, generally parallel surfaces the first flange 56 and the panel 26, or where the gap is greater than about ½ inch, an anti-intrusion wedge 59 may be disposed between the post 24 and the panel 26, as shown in
Referring again to
The portions of the frame 84 disposed on the side edges of the panel 26 are each attached to channel beams 88, which have a generally C-shaped cross section. Support members 90 may be attached between the frame 84 and the channel beam 88 to enhance structural rigidity, as shown in
Referring to
The traffic noise barrier system 10 provides a traffic noise barrier wall 16 supported by a longitudinal barrier 14, which can be located near a selected section of a roadway, railway, aircraft runway, waterway, parking lot, walkway, and the like. The longitudinal beams 32, 34 and 36 are configured to redirect portions of an errant vehicle that may intrude into the area above the top surface 20 of the longitudinal barrier away from the panels 26. The longitudinal beams 32, 34, and 36 redirect energy of the errant vehicle away from the panels 26 such that the panels 26 and any fragments of the panels, remain attached to the traffic noise barrier wall 16. As a result, the longitudinal beams 32, 34 and 36 prevent debris that would otherwise present a hazard to the occupants of the vehicle, surrounding traffic, and/or pedestrians around or below the barrier. In addition, the longitudinal beams 32, 34 and 36 prevent an errant vehicle from snagging on the upstanding posts 24. As a result, the noise barrier wall 16 may be positioned close to traffic, while reducing or eliminating the vehicle snagging, occupant compartment intrusion and deformation, and debris concerns associated with traffic noise barriers of the prior art. This is particularly advantageous in applications, such as on bridges and the like, where space for the noise barrier wall is limited. In addition, the traffic noise barrier system 10 allows the use of transparent panels 26, which allow travelers on the path of traffic 12 to view businesses and scenery outside the path of traffic 12. Also, the use of reinforced panels 26 helps to further ensure that the panels 26 will not become a debris hazard or vehicle intrusion hazard.
A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
The present application claims the benefit of U.S. Provisional Patent Application No. 60/559,738 filed Apr. 6, 2004 and entitled “Traffic Noise Barrier System”, which is incorporated by reference herein in its entirety.
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| Number | Date | Country | |
|---|---|---|---|
| 20050265780 A1 | Dec 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60559738 | Apr 2004 | US |
