The present invention relates to a multipurpose road safety barrier, that is, to a barrier adaptable for being used on the side of a bridge, or as lateral barrier, or as a traffic divider, and which can also be utilized (provided it is appropriately modified) as a support for a sound proofing screen or a screen for protection against the throw of objects. The barrier may be subjected to type approval in various classes corresponding to different resistances, up to the one corresponding to the maximum resistance (H4).
The barrier allows to dampen the collision, by way of a controlled deceleration, in case of light motorcars, while stopping the motion of heavy vehicles.
Road barriers of the wall kind and having a New Jersey (NJ) profile, which are made of monolithic blocks of concrete and which, after their assembling, give rise to a high quality protection, are already known in the art. In those barriers the calibration of the deceleration is obtained, in case of motorcars and generally of light vehicles, by means of the lifting of the vehicle due to the New Jersey shape, and at the same time, due to the presence of sliding shoes, if any, which facilitate the displacement of the barrier and which are interposed between the barrier and its support. Therefore, if the impact angle is restricted, the motorcar is again deviated towards the carriageway, whereas, if it is noticeable, the sliding shoes will promote the displacement of the barrier and calibrate the deceleration values, as mentioned above.
The barriers of the wall type, even if provided with slide facilitating devices (shoes) acting during part of the maximum allowable displacement, as disclosed in some patent applications of the same applicant, and even if provided with a projecting socle (base) having a New Jersey profile or a different configuration, always give rise to a deceleration caused by the collision, and to relevant components of the same in the longitudinal, transversal, and vertical direction with respect to the direction of motion.
In particular, the vertical component is very strong for those types of barriers, and also the transversal component is usually of an impulsive nature (the longitudinal component is more distributed in time). The first of these components has a beneficial effect on the dissipation of kinetic energy of motorcars, since it converts the same into potential energy (lifting), which will be returned after some time, but its generation must not occur simultaneously to that of the transversal impulsive component, because otherwise both components contribute simultaneously to the amount of acceleration given by the ASI (Acceleration Severity Index), the latter being used during type approval tests for the evaluation of the maximum admissible energy to which the passengers of the motorcar may be subjected, under standard extreme conditions of type tests for road barriers.
“U.S. Pat. No. 4,681,302 discloses a barrier for dissipating kinetic energy upon impact by a moving vehicle. The barrier modules may be filled with water to increase their weight and they are resiliently deformable to return to their original shape after being struck.
The barrier disclosed in this document, may form a traffic divider and it captures the vehicle tire, tending to slow the tire and preventing it from climbing and the vehicle from vaulting.
This kind of barrier includes also traction spoiler channels to reduce the area of contact between the barrier and the tires of a vehicle.
While this patent U.S. Pat. No. 4,681,302 already contains the idea of realising a deformable barrier, this barrier does not allow the wheel to climb, so as to convert part of the vehicle kinetic energy into potential energy. Moreover, this barrier is not resistant enough to be used as a “bivalent barrier”, that is a barrier stopping heavy vehicles as well as light vehicles.
Therefore, although it may be very useful in certain cases, it does not belong to the same category of barriers as those of the present invention, and consequently it does not achieve the objects of the present invention.”
An object of the present invention is to shift in time the occurrence of the transversal acceleration with respect to the occurrence of the vertical acceleration, so that they will not add at the same time.
Another object of the invention is to further “dilute” in time the transversal component, which—as mentioned above—has an impulsive nature.
A third object of the invention is to realize barriers whose resistance may be approved during type tests and be assigned, according to the embodiment in question, to any of the classes H2 to H4.
A fourth object of the invention is to provide a modular type barrier, in order to reduce to a minimum the operations to be carried out on existing infrastructures, and reducing at the same time the risk of accidents during the laying, while obtaining an optimization of production costs.
A fifth object of the present invention, depending on the preceding one, is to realize a barrier made of monolithic blocks and modules which can be directly connected to one another with a minimum laying time and are adaptable to any kind of road structure.
A further object is to include in the barrier typology of the present invention, all particular constructive means which are already used in this technical field, like longitudinal connection bars between modules, which are made of special materials with a controlled ductility, or ductile screw anchors having a predetermined resistance to breakage, and possibly friction reducing shoes, thereby increasing the system reliability.
According to the invention, the innovative barrier obtains the dampening of the collision caused by a light vehicle, in a more effective way with respect to the known art, by dividing up the “small wall” formed by a traditional barrier, into two elements, a resistant one (hereinafter called element A) and a dampening one (hereinafter called element B).
It should be noted that the dampening element B always faces the carriageway, and is located in front of the resistant element A.
A symmetric single-row traffic divider will then be formed by two elements B located on both sides of the central resistant element A.
In case of a barrier used for the side of a bridge or of a lateral barrier, which is asymmetric, there will be only a single dampening element B and a rear resistant element A.
The element B is located at the foot of the element A, so as to form a monolithic socle extending along the whole length of the element A (which is itself monolithic).
The element A serves for stopping—in case of low energy impacts—the displacement of the other (front) element B, whose purpose is instead to receive and absorb a first part of the impact energy of a goods vehicle or the whole amount of impact energy of a light motorcar; the dampening of this energy will occur according to multiple processes described later on, related to the deformability of the element B, and/or to the interposition of dissipating material between the two elements A and B, and/or to the kind of connection of the front element B with respect to the support, by means of calibrated friction (shoes), or to the connection with the second resistant element A, through anchor means and/or mutually fitted parts (restricted joints).
The barrier, depending on its use, will be;
The form of the dampening element B corresponds in general to the shape of a socle, which complements the shape of the rear element A, so that, in case one intends to realize an NJ barrier, the barrier (A plus B) will assume the shape of a traditional New Jersey barrier. In general, the socle may have a shape different from that of an NJ profile, e.g. the shape may be rounded, elliptical, etc., provided it is suited for the intended purposes. The overall profile of the barrier will be defined by the profile of both elements A and B.
By the introduction of a deformable element at the “wall” base, it is possible to obtain the following:
The use of appropriate anchor means, together with the resistant element A, of an (energy) dissipating material—if any—interposed between the elements A and B, and of the deformable material making up the socle B, will serve for the purpose of a better calibration of the described operation.
This aspect of the invention relates to the control (calibration) of light impacts; for what concerns higher energy impacts, up to the maximum energy contemplated by the rules on type approval, the resistance will be provided by the resistant element, whose height, transversal dimension, and specific weight, may be arbitrarily chosen, depending on the function of the barrier (safety and screen function, or only safety). The resistant element A can be made of concrete, including an internal reinforcement, or by other materials, e.g. steel of suitable sheet thickness, whereas the dampening element may be made of plastics, steel, or possibly of concrete, but in the latter case an energy dissipating material will be interposed between elements A and B.
In case the socle B is manufactured using plastics, it is possible to employ a reticular, honeycomb, or hollow structure, or a structure filled with water and an antifreeze.
The present invention will now be described in more detail by means of some examples of certain specific embodiments thereof, given by way of example only, and not for limiting purposes, said embodiments being shown in the annexed drawings, in which:
a schematically shows a cross section of an asymmetric, double effect, New Jersey type barrier, according to the present invention, comprising a resistant and a dampening element;
b schematically shows a cross section of a symmetric double effect and single-row type barrier (traffic divider), according to the present invention, including two elements B;
a is a cross section of a possible embodiment of an anchored asymmetric barrier, according to the invention, acting as a guard (parapet);
b is a cross section of an embodiment of an asymmetric barrier anchored to the curbstone, acting as a guard and screen;
a and 1b are schematic views of barrier typologies, showing how the barrier of the invention comprises a resistant element A and a dampening element B (in case of an asymmetric barrier for the side of a bridge or of a lateral barrier), or respectively, two dampening elements B (in case of a symmetric single-row type traffic divider). Obviously, the constructive details will be explained in the following description, with reference to the corresponding figures. Moreover, it should be clear that the socle B, while having a shape of a New Jersey socle in
a and 2b show how the resistant element may be anchored to the curbstone using means known in the art (ductile screw anchors with a predetermined threshold of breakage), and as illustrated in more detail in the description of
Said friction reducing shoes will be disposed below the socle B or below the resistant element A (see FIG. 20 and the related description for the latter case). The shoes could—possibly—be used in case of a concrete made socle, in the embodiment interposing dampening elements between the two elements A, B, in order to reduce friction between the socle and its supporting surface.
In
Following the natural order of the Figures,
While in
The embodiment of
Examples of concentrated dissipating means are: helical steel-made springs, bundles or “packages” of entangled steel fibers as used on a different scale for earthquake-proof supports (not shown), etc.
A further class of dampening elements B is that of plastic made elements. In
In
This solution which utilizes the strips or blades usually employed for the guardrails including posts and strips, has the advantage of recycling materials which are already used.
The deformation of the blade or strip has the effect of diluting in time the transversal component, and allows at the same time the ascent of the vehicle. An obvious possible variant is that making use of a blade mounted vertically with respect to element A (not shown in the drawings).
It is obvious that the longitudinal septa 19 may be replaced by a different structure (a reticular or a honeycomb structure, etc.).
An energy dissipator made of plastics, and without inner septa, filled with water and an antifreeze or salt, to prevent ice formation, in case of impact during the winter, is illustrated in
So as to prevent the immediate compression of the water, the socle 21, 21′ or 21″ may be filled only partially with water and antifreeze or salt.
In
In
It is obvious that possible combinations or variants of all embodiments of the socle which have been illustrated above, should not be excluded, with respect to features like the inner structure, the type of connection with element A, the use of slide shoes in case of a socle made of concrete, etc.
The calibration of the decelerations may therefore be obtained by varying the socle mass, or the type of connection with A, or else by providing a possibility of free displacement of the lower part of the socle (see FIGS. 3 and 5), etc.
The screen 24 (e.g. a net for the protection against the throw of objects, a screen for sound insulation, or a windscreen) is mounted on the upper part of A, and has a known linear weight given in kg/m. Sound absorbers 25 (with a known linear weight) are arranged on the rear part of A, inside recesses 26. The element A is anchored to the curbstone, e.g. by means of ductile screw anchors 29 passing through the steel plate 30, the latter forming a single body or piece with the concrete of A.
Steel made connection means 28, provided on plate 30, and embedded during the casting of the concrete, ensure a reliable connection between the plate and the concrete of A. Anchor means which are more resistant and/or easier to realize, will be described later with reference to
Bolts 27 are used as rear anchor means against the force of the wind, and have a reduced resistance to shearing in order to allow the displacements following the impact. The screw anchors 29 on the opposite side have the same function too; moreover, they deform themselves in a controlled manner and have a predetermined resistance to breakage.
The resistant element A has—in the embodiment of FIG. 19—a large sized structure, and can support both the whole mass of the upper screen 24 and the above mentioned noise absorbers 25, which selectively absorb medium/low frequency noise. A crash test for type approval performed only having regard to the safety aspect, could be carried out with the sound absorbing parts simply simulated with respect to their mass and position; this allows to use barriers which, for what concerns those parts, are different from the point of view of their function as an acoustic insulation screen, but are identical with respect to their safety function.
A U-shaped sheet steel 31 presents a slot 32 for the insertion of the screw anchor 29. Through the slits 34 of the U-shaped part, there passes a bracket 38 which is also U-shaped and which has two arms terminating in two hook portions 35, the latter engaging further brackets 37 and 37′, embedded as reinforcements in the concrete of A whose boundary is denoted by dotted lines 33. The reinforced-concrete rods 36, 36′ of the conventional reinforcement pass above the sheet metal 31. The disclosed connection realizes a chain of connections between the components 31 and 38 on the one hand, and, on the other, between 37, 37′.
The described connection system has the advantage that it does not require welded parts.
The number 33 denotes the boundary of the region occupied by the concrete of A.
The front portion 39 (which is located on the back side in the Fig.) of the sheet metal 31, projects beyond the foot of the concrete element A.
A U-shaped sheet steel 31 presents a slot 32 for the insertion of the screw anchor 29. Through the slits 34 of the U-shaped part, there passes a bracket 38 which is also U-shaped and which has two arms terminating in two hook portions 35, the latter engaging further brackets 37 and 37′, embedded as reinforcements in the concrete of A whose boundary is denoted by dotted lines 33. The reinforced-concrete rods 36, 36′ of the conventional reinforcement pass above the sheet metal 31. The disclosed connection realizes a chain of connections between the components 31 and 38 on the one hand, and, on the other, between 37, 37′.
The described connection system has the advantage that it does not require welded parts.
The number 33 denotes the boundary of the region occupied by the concrete of A.
The front portion 39 (which is located on the back side in the Fig.) of the sheet metal 31, projects beyond the foot of the concrete element A.
In this case the plate is formed by a box-like element 31′, and the hook portions 35″ which engage the additional brackets 37 and 37′, are welded on the upper surface of the box-like element 31′. The components 31′, 35′ are embedded in the concrete of A. A slot 32′ is formed both on the upper and the lower part of element 31′ (see
Turning again our attention to
It is possible that the resistant element A will, in some cases, not include slide shoes or ductile anchor means for the connection to the support.
As has been already pointed out, the barrier may vary between classes of smaller resistance (H2) and those of maximum resistance (H4). According to Italian regulations, this means that the impact energy the barrier—according to its different embodiments—must be able to withstand, varies from 128 Kj for the H2 class, to 572 Kj or 724 Kj for the H4 class, depending on the vehicle type.
Moreover the barrier must prevent lorries from vaulting, wherein said lorries have a maximum height for their center of gravity which must not exceed about 1,60 meters. This means that the barrier must have excellent features in order to prevent vaulting and thereby to avoid very serious consequences not only to the passengers of the colliding vehicle, but also to possible railways, roads, buildings, etc. located below a bridge etc.
At the same time, the barrier must deform itself and be able to move backwards, so as to absorb the impact energy in a controlled manner.
Taking into account the fact that usually a large space is not available, the transversal movement of the barrier, which is in any case desirable, must always be restricted.
The measured components of the accelerations, must give rise to an ASI
ASI=[(ax/12)2+(ay/8)2+(az/10)2]1/2
Number | Date | Country | Kind |
---|---|---|---|
RM99A0464 | Jul 1999 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCTIT00/00248 | 6/15/2000 | WO | 00 | 1/22/2002 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO0106063 | 1/25/2001 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
1718875 | Ramsey | Jun 1929 | A |
3332666 | Gray | Jul 1967 | A |
3385564 | Persicke | May 1968 | A |
3712589 | Peterson et al. | Jan 1973 | A |
3844538 | Colan | Oct 1974 | A |
4681302 | Thompson | Jul 1987 | A |
5123773 | Yodock | Jun 1992 | A |
5137391 | Ballesteros | Aug 1992 | A |
5697728 | Camomilla et al. | Dec 1997 | A |
5836714 | Christensen | Nov 1998 | A |
5851005 | Muller et al. | Dec 1998 | A |
6086285 | Christensen | Jul 2000 | A |
6149134 | Bank et al. | Nov 2000 | A |
6276667 | Arthur | Aug 2001 | B1 |
6533250 | Arthur | Mar 2003 | B2 |
6533495 | Williams et al. | Mar 2003 | B1 |
Number | Date | Country |
---|---|---|
644358 | Sep 1964 | BE |
1 534 499 | Jun 1969 | DE |
2 200 183 | Jul 1973 | DE |
7420685 | Oct 1974 | DE |
25 13 436 | Oct 1975 | DE |
0 518 304 | Dec 1992 | EP |
1 347 771 | Feb 1974 | GB |
2-157308 | Jun 1990 | JP |
WO 9503453 | Feb 1995 | WO |