WO2022130115A1

WO2022130115A1 - Road safety barriers with reinforced ground concatenation and installation method thereof

Info

Publication number: WO2022130115A1
Application number: PCT/IB2021/061370
Authority: WO
Inventors: Hannes NIEDERKOFLER
Original assignee: Stratec Rt Srl
Priority date: 2020-12-16
Filing date: 2021-12-06
Publication date: 2022-06-23
Also published as: EP4263948A1; IT202000030929A1

Abstract

This safety road barrier (101) is composed of a system of elements integrated together which includes a set of vertical uprights (110) fixed to the ground individually, and at least one horizontal blockout bar (130) composed of a sequence of longitudinal segments connected to each other, supported by said uprights, positioned at a height suitable for containing a vehicle's exit from the road, and which connects a sequence of uprights to each other. Furthermore, said safety road barrier is characterized by the fact that it also includes a further longitudinal element (161) which connects a sequence of uprights together, and which is fixed to the ground.

Description

TITLE: ROAD SAFETY BARRIERS WITH REINFORCED GROUND CONCATENATION

AND INSTALLATION METHOD THEREOF

DESCRIPTION

Technical Field of the Invention

The field of application of this invention concerns the installation of road safety barriers (hereinafter also referred to as "guardrails").

Said barriers are an essential element in ensuring road safety. In fact, in addition to clearly delimiting the edge of the road, they are intended to significantly reduce the consequences of accidents involving vehicles leaving the road.

Known art

The main function of a "guardrail" is to ensure adequate safety standards: for this reason, the so-called "guardrails" are normally subjected to compliance with adequate mechanical standards. These standards, which allow the barrier to be defined compliant with the norm, must be certified. Typically, this occurs through suitable tests (hereinafter also referred to as "crashtests"), subjecting a "guardrail", placed in a real installation context, to collisions with vehicles.

It should be noted that a correct interpretation of the standard should not concern just the safety barrier as such, but also its installation: in essence, although the road barrier manufacturers provide their certified barriers, what really guarantees the road safety is not just the barrier, but the entire system consisting of the road and the barrier (as installed).

Specifically, a "guardrail" must prevent vehicles from exit the road and their overturning, to avoid dangerous collisions with other vehicles and/or elements outside the road. At the same time, it must be able to absorb and dissipate all, or part of, the kinetic energy possessed by the vehicle at the moment of impact, reducing, in a controlled way, the decelerations induced by the collision to the occupants of the vehicle, and allowing its gradual return to the carriageway by stopping its travel, possibly near the roadside.

These behaviors of the "guardrail" can be achieved in different ways, focusing on the stability of the installation, providing that the uprights of the "guardrail" deform, but do not detach from the ground, or also providing that some of these uprights detach from the ground. These different strategies may depend on the terrain on which the "guardrail" is installed, but also on the required safety requirements: it is clear that a road located on the edge of a precipice or on the embankment of a watercourse should favor the objective of preventing off-road exits, while a road with free land on the sides can be safer if vehicles affected by an accident are allowed to stop their run off the carriageway. Therefore, the real safety requirements and, consequently, the rules that should guarantee these requirements, can be respected in many ways: what must be assessed is the overall result, which has to do with the safety of a road as a whole, equipped with appropriate safety barriers.

The combination of mechanical robustness (aimed at containing the vehicle), the elastic-plastic deformability (aimed at reducing the decelerations induced by the impact, by controlling the dissipation of kinetic energy) and the breaking, or detachment, of some elements of the "guardrail”, sets a significant and not a simple technical problem for the construction and installation of these road safety barriers.

The common practice, based on the known technique, does not adequately consider these aspects concerning safety, and it is not uncommon that, in the event of an accident, the authority which is responsible of the management of the road is responsible also for the consequences of this accident.

It is quite frequent that the "guardrails" installed along the roads do not normally meet the technical safety requirements, because their installation does not reflect the certification conditions, with serious risk for the consequences of any accidents.

After all, the huge variety of installation conditions makes it very difficult to build roads in which the installation conditions of the “guardrail” are homogeneous.

In summary, it the known technique is satisfactory in relation with the materials and the elements that are used for the realization of the "guardrail” as a stand-alone product, (intended as a system certified by authorized laboratories); while it still remains substantially unresolved the aspect concerning its installation, which often does not replicate the certification conditions of the "crashtests".

In conclusion, a significant number of installed "guardrails" do not meet the real safety requirements, due to installation differences.

A typical situation in which the installation doesn’t meet safety standards is considered below, more in detail. This is the very common case in which the uprights of a "guardrail" are planted into the ground by a maneuver performed with a so-called "pile driver". This maneuver consists in vertically positioning the upright of the "guardrail" at the point where it must be driven into the ground, after which, with a mechanically operated hammer, it is beaten and driven into the ground (normally at a depth more or less equivalent to the part emerging from the ground).

This technique has its main advantage in the speed and simplicity of installation. The upright has a very linear structure consisting of a bar normally with a constant profile in the buried part.

On the other hand, the tightness of the installation largely depends on the compactness and characteristics of the ground that, if not particularly compact, modifies the behavior of the road barrier in the event of a vehicle collision: in this case, in fact, being the uprights not well stable in the ground, as a consequence of the impact of vehicles, they will tend to rotate rigidly in the ground, instead of flexing, reducing their deformation capacity and therefore the capacity to absorb and dissipate the necessary amount of kinetic energy; but, above all, the uprights fixed on the ground normally exhibit very different behaviors depending on the trait of road in which they are planted, with consequent different performances with respect to the safety they can guarantee.

The known art proposes some solutions that aim to overcome this problem related to the unevenness of installation, i.e., a problem due to the installation of the "guardrails" on roads whose edge is made up of soils whose compactness cannot be controlled with the necessary accuracy.

Some solutions provide for the use of uprights whose part to be fixed to the ground has an appropriate shape to ensure greater firmness, for example by using uprights associated with an enlarged plate that makes a greater quantity of soil collaborate with the upright firmness, when the "guardrail” is subjected to a violent impact caused by an accident.

These solutions based on the use of uprights, whose shape of the buried part, has an appropriate conformation, make the steadiness of the uprights more secure, but they do not solve the problem of installation unevenness; they also provide particularly improved performance only when the ground is compact; and they end up to produce an almost negligible effect precisely in the cases in which such improved performance would be needed most, i.e., in installations on less compact ground.

More interesting are the solutions that involve the use of anchors that grip the ground below the road surface.

The interest derives from the fact that the ground under the road surface is normally compacted in order to avoid the subsidence of the roadway due to the weight of the vehicles in transit. It is evident that such an inconvenience (i.e., the subsidence of the roadway) must be absolutely avoided, and therefore the surface on which the roads are built is always suitably prepared and, in particular, is pressed so as to make it very compact.

A solution of this type is taught in the patent application n. PCT/IB2019/050262 - "Reinforcement element for fixing at the base, in ground, the uprights of roadside safety barriers" (by the same authors of the present patent application), which describes an upright connected, through a connecting element which works in tension, to one or more plates buried under the road surface. This solution, in its generality, is conceptually quite simple, but in its actual implementation it poses a series of problems, and requires further refinements, both to solve some installation problems, and to achieve a real quantitative control of the performance of the "guardrail", as a system, in the event of an accident.

Another solution, which is based on the exploitation of the greater compactness of the ground under the roadway, is taught in WO 2019/008525 A1 - "Device for anchoring safety road barriers poles to the ground". This is a solution that provides for a helical element, the cost of which is presumably very significant compared to the cost of the other elements of the "guardrail"; this element is suitable for being inserted into the ground by means of a screwing maneuver.

The solution taught in WO 2019/008525 A1 presents the problems of the previous one and, in addition, the anchoring system taught in WO 2019/008525 A1 , in cases where it is most needed (i.e., when the roadside is not very compact, and does not offer adequate resistance), must penetrate deep enough into the ground below the roadway, in a zone that is often occupied by underground services. It is definitely preferable that the "road system" as a whole, including the appropriately installed safety barriers, does not invade the ground below the road substrate (approximately up to a depth of the order of one meter): this in order to decouple, as much as possible, the management of underground services (often associated with road layouts) from the road management

A further problem, currently largely neglected, consists in having road barriers whose behavior can be controlled according to the trait of road.

In fact, there are sections of road where the priority objective of a safety barrier is to avoid going off the road, for example, due to the presence of a precipice, or a watercourse, or to protect what there is outside the street itself. In other sections, however, it is preferable that the vehicles involved in an accident go off the road, and what matters most is that their kinetic energy is dissipated, avoiding violent crashes against the barrier itself.

In fact, there are different types of road barriers, characterized by resistance parameters that allow them to be classified according to the behavior they must assume during accidents, defining the forces they must resist before bending or breaking; but there are no barriers where these parameters can be easily adjusted even during installation. Normally, a certain type of barrier, defined by the project, is installed in long stretches of road without variations, and the diversity of behavior depends only on the ground on which the installation takes place.

In other words, variable performances are obtained in a substantially random way, without the possibility to exercise a real control of the performances that this barrier should guarantee, so that they depend (as it should be) on the real security needs that are required in the different road traits.

A quite satisfactory solution to the problem of controlling the performance of a "guardrail" in terms of resistance, is provided in the patent application n. PCT/IT2020/000075 - “Road equipped with road safety barriers fixed to the ground and installation method thereof " (by the same authors of the present patent application). This patent application indicates an overall system consisting of a traditional "guardrail" (i.e., as in the known art) associated with suitable anchoring systems which, while remaining universal (i.e., applicable in any installation context), allow adjustments to be made for adapting to various installation contexts. The approach proposed in this patent application is innovative in itself, and consists in not considering the safety barriers as a separate element to be installed on the roadside, but part of an overall "road system" which also includes safety barriers. And the safety of this “road system” depends on all its elements, on how they are installed and on how they integrate with each other.

It can be concluded that the known art proposes solutions that, although still not very widespread, are certainly effective in addressing the problem of fixing the individual uprights of a "guardrail" to the ground, taking into account the different installation conditions.

However, the individual operation of fixing to the ground, carried out according to known solutions, even the most satisfactory ones to date, is still a rather laborious process: which is why the simple driving with a pile-driving machine, although it is a solution which brings very serious contraindications, continues to be a still very popular choice. Consequently, if innovative measures were introduced, which, with the same result, offered significant simplifications to the installation processes, these solutions would certainly be received with great interest.

Furthermore, the effect of the chaining together of the various uprights of a "guardrail" does not yet appear sufficiently exploited. It is important to note that the tightness of a safety barrier, especially in cases where vehicles involved in an accident are tolerated off the road, is not entrusted only to the tightness of the ground fixing of the safety barrier uprights: in fact, since the various uprights are linked to each other by the longitudinal blockout bar, i.e. that metal horizontal containment strip that connects the various uprights to each other, even if some uprights are pulled from the ground, they are in any case retained by this longitudinal blockout bar, which in turn is held by the other uprights offset from the point of impact which are not torn off by the impact. Therefore, if said longitudinal blockout bar is robust, and well connected (in its component segments, and to the uprights that support it), in the event of accidents, although very violent, a certain number of uprights can be seen detaching from the ground, with the longitudinal blockout bar that consequently deforms and deviates from the road, but which, being held by other uprights which do not detach from the ground, still performs a containment function. The chaining effect exerted by the longitudinal blockout bar, therefore, can be very effective in many cases in which the fixing of road barriers to the ground cannot guarantee an adequate tightness.

Despite the considerable importance of the longitudinal blockout bar in safety barriers, the technologies concerning this element of the "guardrail" are definitely consolidated. The significant and recent evolutions, aimed at improving the performances associated with said longitudinal blockout bar, are therefore not particularly numerous. Among these we can mention the solution taught in the patent application n. EP 17847772.5 - "System for connecting the contiguous segments of the horizontal blockout bar in a roadside barrier, and method thereof" (by the same authors of the present patent application), in which an additional element is foreseen for the connection of the single segments of which this longitudinal blockout bar is made of: this new additional element offers particular advantages above all in terms of conformity of the installations. Other improvements have been introduced by adding an additional upper bar which, among other things, further strengthens the chaining, or an additional lower bar positioned to ensure good containment even of the motorcycles lying down which could impact the "guardrail" at a very low height in case of accidents.

However, it can be understood that the great potential, in terms of safety, which can be achieved by exploiting the chaining effect, can be further improved through the proposal of innovative chaining solutions that go beyond the effect offered by the longitudinal blockout bar (or by the longitudinal bars, if there is more than one).

Description of the Invention

The main purpose of the present invention, therefore, is to indicate a new type of safety road barrier in which the chaining effect between the various uprights is reinforced compared to known solutions. And this linkage is suitable for creating a real "road system", in which each section of the safety barrier can be installed with reasonable certainty of compliance with the required safety requirements, as these requirements can be defined differently depending on the case.

Furthermore, the safety barrier indicated in the invention must offer the possibility of exploiting this greater linkage both to increase the resistance of the barrier itself and to improve its fixing to the ground, according to the safety requirements to which the barrier must fulfill. Since these safety requirements can also be defined during construction, without necessarily requiring an excessively detailed design of the safety barriers, able to specify punctually the characteristics of the barrier along the entire length of a road.

In particular, the safety barrier indicated in the invention must be able to be installed in such a way as to react both with plastic deformations and with programmed breakages of some elements, as these behaviors can be defined even during installation.

It is clear that the control of some mechanical requirements during construction cannot be achieved by installation of different barriers depending on the requirements to be obtained, because this solution would pose substantial problems when ordering the materials; on the other hand, it is desirable to have a single barrier, which has suitable adjustment elements to allow the control of mechanical requirements on the field.

Furthermore, another purpose of the present invention is to indicate a "road system", including special safety barriers, in which the installation of the barriers is as easy as possible, and which is also applicable as an adaptation of existing "guardrails". The installation must be able to be carried out with typical instrumentation for the operators in this sector, without requiring them to have specific equipment, built ad-hoc for the particular type of "guardrail" that must be installed.

A further objective of the present invention is to indicate a system which does not significantly invade the roadway, substantially, it should be applied only on the terrain of the roadside.

These objectives can be reached by a road safety barrier composed of a system of elements integrated together, which includes a set of vertical uprights individually fixed to the ground in a row along the edge of a road, and at least one longitudinal blockout bar composed of a sequence of horizontal segments connected to each other, supported by said uprights, positioned at a height suitable for containing the exit from the road of a vehicle, and which connects a sequence of uprights to each other.

Moreover, said safety road safety barrier is characterized by the fact that it also comprises a further longitudinal element, said ground connection bar, which connects a sequence of uprights to each other, and which is also fixed to the ground.

This system of integrated elements, which can also be understood as a real "road system" consisting of the road itself equipped with its own safety barrier, has the further advantage of being able to be implemented even in contexts where a road barrier already exists, which may have a low solidity and consistency, and which therefore needs to be reinforced and brought up to standard.

In fact, a safety barrier built according to the teachings of the invention is suitable to be installed and built even when the road already exists, without interventions affecting the roadway; moreover, it can be implemented even when there is already a "guardrail" without said further longitudinal element fixed to the ground. It is therefore a very effective invention to provide for the adaptation of existing contexts; and it can often be implemented without necessarily removing the old "guardrail" to replace it with a new one made according to the invention.

Brief Description of the Drawings

The main advantage of the present invention consists in the fact that any "guardrail" installed according to the teachings of the present invention satisfies all the main requirements for which it was conceived, designed and certified.

Moreover, this invention also has further advantages, which will become more evident from the following description, from some examples of practical embodiments which illustrate further details, from the attached claims which form an integral part of the present description, and from the attached figures in which: Figures 1a and 1b show the main elements of a safety road barrier ("guardrail") according to the known art; Figures 2a and 2b show a "guardrail" according to the prior art, fixed to the base by driving the uprights into the ground in two different installation modes; Figure 3 shows an overall view of a safety road barrier according to the invention; Figures 4a and 4b show some characterizing details of a form of implementation of a safety road barrier according to the invention; Figures 5a and 5b show some characterizing details of another form of implementation of a safety road barrier according to the invention;

/ Figures 6a and 6b show some examples of programmed resistance elements included in some forms of implementation of a road safety barrier according to the invention; Figures 7a and 7b show some characterizing details of yet another form of implementation of a road safety barrier according to the invention; Figures 8a and 8b show some characterizing details of yet another form of implementation of a road safety barrier according to the invention.

Detailed Description

Figure 1a shows a piece of a typical road safety barrier (also called a ‘guardrail”), indicated, as a whole with the number 100. This barrier is seen from inside the road and, in general, it is composed of the elements listed below:

• substantially vertical elements, normally called uprights, which support the barrier itself, and indicated with the number 110 (also in the following figures);

• a horizontal containment metal strip, indicated with the number 130 also called horizontal blockout bar;

• an eventual upper beam, indicated with the number 140.

The uprights 110, in a typical and widespread installation method, are fixed to the base by driving them into the ground. The number 200 indicates the land where the "guardrail" is installed, in the cases considered by the present invention.

Said horizontal blockout bar 130 is shown in the figure only in part since it is a very long element which, in addition to exercising the function of containing the vehicles, connects a sequence of uprights 110 to each other, also giving them greater resistance. In fact, if one or more uprights 110 were to be torn off as a result of a violent impact by a vehicle, said longitudinal containment current 130 would remain connected to the other uprights 110, however containing, albeit to a lesser extent, the exit of the vehicle. Since it is an element of non-predefined length, said horizontal blockout bar 130 is necessarily composed of a sequence of segments connected to each other. Shown in Figure 1a, and indicated with the numbers with 131 and 132, there are two segments of the horizontal blockout bar 130 connected to each other by bolting, as occurs in the great majority of cases. In the case of Figure 1a, this bolting is performed with four bolts indicated with the number 133; however, other connection methods are also possible; what matters is that the connection between the segments is firmly established, so that the horizontal blockout bar 130 behaves substantially as a single and continuous body, and guarantees the appropriate mechanical certification performances.

Figure 1 b represents the same “guardrail” shown in Figure 1a, but it is seen in a section orthogonal to the direction of the road, where the numbers indicate the same elements as in Figure 1a.

Figure 1b also allows the viewing of a spacer element between the upright 110 and the horizontal blockout bar 130. Said spacer element is indicated with the number 120, it has the main function of connecting the horizontal blockout bar 130 with the upright 110, and plays an important role in determining the performance of the "guardrail'' as a whole.

Another feature, which can be appreciated from the view of Figure 1b, is the profile of the horizontal blockout bar 130. This profile is the result of a long evolutionary process and has the advantage of ensuring an excellent compromise between mechanical performance and costs. This may be the reason why said horizontal blockout bar 130 is an element whose construction is very well established and whose operating principles have not been the subject of many innovations in recent times.

It has already been stated that the mechanical performance of road safety barriers according to the prior art are satisfactory when they can operate in nominal conditions, because only in such conditions all the parts of the "guardrail system" (meaning all its component parts briefly summarized with the help of figures 1) work according to the design specifications when an accident occurs, and the barrier is subjected to strong impacts The nominal conditions are those that correspond to the test conditions during the so-called "crash-tests"

There are various ways in which the performance of a "guardrail" can be tested: ranging from tests carried out in the laboratory to real tests in which a true vehicle simulates an accident and hits the "guardrail". The tests performed by simulations with real vehicles are certainly the most significant, as they clearly show whether the "guardrail" performs its main function, which is the containment of a vehicle that is getting out of the road and stops its run in a point that minimizes the dangerous consequences of a simulated accident. This containment function always requires the complete dissipation of the kinetic energy of the vehicle involved in the accident, and this dissipation can occur in many ways: through the plastic deformation of the "guardrail", or through the breaking of parts thereof. In some cases, it is required that the "guardrail" does not detach from the ground where it is installed, while in other cases, some uprights may also detach from the ground and the containment takes place due to the holding of the horizontal blockout bar which remains attached to a plurality of uprights, some of which, when stressed by an impact of a mass having a reduced momentum, do not detach from the ground.

Ultimately, the "optimal guardrail" is the one that performs its function in the best possible way, and its behavior depends not only on the "guardrail" as such, but also on the type of road and the characteristics of the ground on which it is fixed to the ground.

Finally, in Figure 1b, above the ground 200, and indicated with the number 210, it is also represented the road surface, which typically consists of a layer of asphalt with a thickness of about ten centimeters.

Figure 2a illustrates the behavior of a "guardrail" installed in the ground on the road quay, as occurs in the vast majority of real cases. In fact, in the majority of real installations the uprights 110 of a "guardrail" are simply driven into the ground 200 without particular attention to the characteristics of this ground 200. Therefore, when the "guardrail" is hit by an impact force, indicated in Figure 2a with the number 400, the stiffness of the road quay is often modest, typically it is not sufficient to keep vertical the upright 110, which does not deform and rotates as indicated in Figure 2 (in which the rotated position of the upright 110 is represented with a dashed line).

Figure 2b instead shows a detail of a road equipped with a safety barrier in which there are some reinforcing elements with the function of keeping the upright 110 fixed to the ground more firmly.

Differently from Figure 2a, in which the characteristics of the ground 200 were not substantially relevant (as they were not adequately taken into account for the installation of the "guardrail"), the ground is here depicted in greater detail. In fact, the number 201 indicates an area of land with characteristics different from the generic soil 200. In fact, the roadway on which a road is built, normally (practically always) undergoes a stabilization treatment by compacting and pressing the terrain on which the road surface is then spread. In fact, a so-called road substrate (or roadbed) is always created, whose depth is of the order of one meter (generally the roadbed is designed according to the geological characteristics of the terrain on which the road is built).

Said road substrate 201 is essential, and serves to prevent subsidence phenomena of the road when it is loaded with the weight generated by vehicular traffic. Being a treated terrain, said road substrate 201 has known compactness characteristics, generally very good, because, as said, it is a terrain which must not deform under the weight of the vehicles passing on the road. Said road substrate 201 is obviously under the road surface, always indicated with the number 210; certainly, a part of terrain treated as the road substrate also extends towards the roadside, but its characteristics along the edges are certainly not as controlled as those below the road surface, and they are somehow affected by the characteristics of the surrounding terrain 200

The "road substrate " 201 therefore represents the ideal ground for anchoring the uprights 110 for the installation of safety barriers. Anchors of this type are known, for example from patent application no. PCT/IT2020/000075 - "Road equipped with road safety barriers fixed to the ground and installation method thereof" (by the same authors of this patent application and already mentioned above).

The system taught in the aforementioned patent application is summarized in figure 2b and has a particular composition as it includes at least three distinct subsystems connected to each other: a system of vertical plates, indicated with the number 153, a connecting rod, indicated with the number 152, and a joining element, indicated with the number 151.

Said system of vertical plates 153 is designed to be fixed vertically in the road substrate 201 , where this is more compact, in an area below the road surface 210, possibly not too close to the edge of the road, and in any case in an area where the road substrate 201 tightness performance is reliable.

Said connecting tie rod 152 is an element which works in tension being connected to said system of vertical plates 153 on one side and to an upright 1 10 on the other, even if, as will be clarified below, the connection with the upright 110 is not a direct connection. The function of said connecting tie rod 152 is to hold the upright 1 10 to which it is connected in the installation position, when the latter is stressed by an impact force, again indicated with the number 400, and coming from the road.

The junction between an upright 1 10 and a connecting tie rod 152, as already mentioned, is not a direct junction: it is implemented through said junction element 151. The functions of said junction element 151 are more than one: in fact, in addition to guaranteeing the junction between an upright 1 10 and a connecting tie rod 152, it allows to use uprights of very simple manufacture, such as those typically used in implementations according to the known art, which can be installed by driving through the use of a pile-driving machine, and which do not require particular conformations to hook onto said connecting tie rod 152.

Furthermore, and this is perhaps the most important characteristic of said junction element 151 : it is an element of rather limited dimensions which is located near the base of the uprights 1 10, in an area not covered by the road surface (so that the maintenance operations are easy), and it is an element which can be sized to break when stressed by predetermined forces.

Basically, said junction element 151 must break before said connecting tie rod 152 breaks and before said system of vertical plates 153 moves due to a particularly high impact force 400 which, acting on the upright 1 10 towards the outside the road could drag the whole system of vertical plates 153.

In short, it is possible to concentrate on said junction element 151 , all the adjustments on the mechanical performances that are intended to be obtained with regard to the behavior of a "guardrail" in the event of an impact. The main problem of anchoring systems such as the one shown in Figure 2b is that it owes its effectiveness to the particular compactness of the ground of which the "road substrate" 201 is made, which is located below the road surface 210.

Of course, these types of anchoring are recommended when their installation is contextual to the construction of the road, but they can be problematic if you want to implement them on existing roads, on which a safety barrier is already present, perhaps installed by simple driving of the uprights 110 on an embankment. In these cases, it is advisable to limit as much as possible (possibly avoid completely) the interventions on the roadway, trying to work on the consolidation of these embankments and on the exploitation of the linkage of the uprights between them.

Figure 3 shows a piece of the road safety barrier view from inside the road, similar to the view presented in Figure 1 a. As in Figure 1a, a "guardrail" is shown, installed by driving the uprights 1 10 into a ground 200, having, in general, not known compactness characteristics.

The piece of the road safety barrier presented in Figure 3 is indicated with the number 101 , and compared to the "guardrails" according to the known art, it includes an additional horizontal element. In fact, in addition to the suspended horizontal elements common to the "guardrails" according to the known art, such as the horizontal blockout bar, always indicated with the number 130, or an upper beam, again indicated with the number 140 (as in the previous figures), there is also a ground connection bar, indicated with the number 161. Obviously, said ground connection bar 161 cannot perform significant containment functions, therefore it could appear less useful than the suspended elements, and perhaps precisely for this reason, up to now, no "guardrails” have been developed with this particular distinctive element.

However, as will be argued below, said ground connection bar 161 can prove to be extremely useful for solving the problems suffered by the "guardrails" according to the known art when they have to be installed by driving the uprights on the roadside ground.

Figure 4a shows, in a very schematic and essential way, a top view of a piece of road safety barrier, such as the one presented in Figure 3, in an implementation form according to the invention. The number 1 10 indicates two uprights, with a “C” profile, fixed to the ground. For the sake of simplicity, Figure 4a does not show the suspended horizontal elements, as they are not useful for illustrating the characteristics of the present invention. The number 161 instead shows the ground connection bar. It is a continuous element placed along the edge of the road, laid on the ground.

In the form of implementation of Figure 4a, said ground connection bar 161 is laid between the row of uprights 1 10 and the asphalt layer, of which the road surface is made, indicated with the number 210. Being said ground connection bar 161 an element of indefinite length, also, as the horizontal blockout bar, it is composed of segments placed in sequence: in the implementation example of Figure 4a two segments connected to each other are shown, and they are indicated respectively with the numbers 161 .1 and 161 .2.

Unlike the other suspended horizontal connection elements, the ground connection bar 161 is both connected to the uprights 110, by means of joining elements (to the uprights), indicated with the number 171 , and fixed to the ground, by means of elements of anchoring (to the ground), indicated with the number 173.

Figure 4b shows the same implementation example shown in Figure 4a, but offers an elevation view. From the view of Figure 4b it can be easily seen how the anchoring element 173 penetrates the ground 200; however, compared to similar anchoring systems, applied in known solutions, which are designed to strengthen the seal of the upright 1 10 (the upright 1 10 being the only element fixed to the ground), the anchoring elements 173 can be more numerous. Since said anchoring elements 173 can be applied along the entire length of the ground connection bar 161 , their number and depth of insertion can be varied according to requirements, thus offering an opportunity to adjust the firmness of the ground installation.

A first interesting characteristic of said ground connection bar 161 is that of being suitable for a very firm ground fixing and, above all, a fixing capable of being adjusted according to requirements.

A second interesting characteristic of said ground connection bar 161 is instead the most evident, and consists in the fact that it constitutes a further link between the uprights 1 10 of the "guardrail'¹ 101 . In fact, said ground connection bar 161 is connected to the uprights 1 10 by means of said joining element 171 by concatenating the uprights 1 10 together.

As already explained, the continuous chaining of the uprights of a "guardrail" is a very effective feature for improving the performance of the "guardrail" in terms of containment of the vehicles, by limiting their exit from the road in the event of accidents. Furthermore, said chaining distributes the effects of the collisions over a longer portion of the "guardrail" 101 , increasing the amount of kinetic energy that the "guardrail" itself is able to dissipate.

The chaining to the ground (with respect to the suspended chaining) also has a further advantage due to the fact that said ground connection bar 161 , does not need to have the same robustness as the suspended horizontal blockout bar 130, since also the ground to which it is anchored contributes to giving it mechanical strength: therefore it can have a lower weight: that is, it can be made with a smaller quantity of material, and consequently it can have a modest impact on the costs of the "guardrail" 101 as a whole.

A third interesting characteristic of said ground connection bar 161 is given by the fact that, once it is well fixed to the ground, it actually acts as a sort of reinforcement curb on the roadside. Therefore, by hooking the base of the uprights 1 10 to it, it also offers a system for fixing the uprights to the ground, which is added to the simple infixion. Figure 5a shows, in a very schematic and essential way, a top view of a piece of a road safety barrier, similar to the one presented in Figure 4a, in an implementation form, again according to the invention, but with a possible variant.

Also in Figure 5a, the number 1 10 indicates two uprights, with a "C" profile, fixed to the ground, and the suspended horizontal elements are not represented, as they are not useful for illustrating the characteristics of the invention. The ground connection bar is still shown with the number 161 , but there is a second ground connection bar, indicated with the number 162.

Figure 5a offers the opportunity to observe how the positioning of said ground connection bar is susceptible of implementation forms according to multiple variants: since this ground connection bar can be positioned between the row of uprights 1 10 and the road surface, or it can be positioned externally with respect to the row of uprights 1 10, or two (or more) connecting bars can be provided, as in the example of Figure 5a and Figure 5b, in which the latter offers an elevation view of the form implementation depicted in Figure 5a.

From a qualitative point of view, it can be observed that both positions of the ground connection bar have relative advantages and disadvantages, but they are both effective for achieving the purposes of the invention.

For example, a ground connection bar 161 positioned closer to the road surface, probably lies on a more compact and more resistant ground than the ground which is externally with respect to the row of uprights 1 10, and therefore the action of the anchoring elements 173 may be more effective. A ground connection bar 162 positioned externally with respect to the row of uprights 110, on the other hand, is more convenient to install, as it allows to work from off the road, and, if positioned in touch with the bases of the uprights 110, automatically offers reinforcement for the fixing to the ground of the latter: opposing their displacement towards the outside when hit by an impact coming from inside the road.

The form of implementation exemplified in Figures 5a and 5b represents a good compromise between the advantages and disadvantages outlined above, so that the anchoring to the ground is ensured on the connecting bar 161 positioned close to the road surface (internally with respect to the row of uprights 1 10) , while a second ground connection bar 162 is located externally to the row of uprights 1 10, abutting on their base, thus offering an excellent reinforcement to their installation: thus contributing to their solidity when these are pushed towards the outside the road as a result of a collision caused by an accident.

From a cost point of view, it is observed that the duplication of the ground connection bars 161 and 162 does not necessarily entail a doubling of costs, since each bar may be made with less material, given that the overall resistance of the ground connection it is guaranteed by the sum of the resistances of the two bars. Figures 6a and 6b allow to highlight a fourth interesting characteristic of said earth connection bar 161 (or 162 or both): a characteristic referred to the modality in which this bar can be connected to the uprights 1 10.

In fact, said joining element 171 is an element of compact size which lends itself to being configured to vary its mechanical performance, so as to offer a further adjustment opportunity, which can be carried out in the field, and which allows the setting of appropriate performance parameters of the overall system. Figure 6a shows a detail of said joining element 171 , which allows to perform a fine adjustment of the programmed breakage.

In a typical embodiment, said joining element 171 is an element shaped to be fixed to said ground connection bar 161 , and to wrap around the base of an upright 110 so as to connect the bar 161 to the upright 1 10. In the present case to which it is considered appropriate that some uprights 110 detach from the ground in the event of a violent impact, in order to manage some accidents allowing the vehicles to exit the road in a controlled manner, but protecting the latter from impact such as to induce excessive deceleration for passengers, it is necessary to provide for a break programmed of some element of the ''guardrail" 101. Said joining element 171 is a privileged object on which to act for this adjustment so that it is subject to a programmed break when stressed by a traction force which tends to detach an upright 1 10 from said junction bar 161 : and said programmed break can be implemented in many different ways.

For example, it is possible to act on the thicknesses of the material of which the part of the junction element 171 that wraps the upright 110 is made; or, on this part of the joining element 171 , initially made with a thickness that gives it high resistance, it is possible to make holes or incisions to create weak points, or it is possible to resort to measures such as those indicated in Figures 6a and 6b.

In Figure 6a, for example, the closure of the joining element 171 , so that it wraps around the upright 1 10, is achieved by inserting one of its parts, indicated with the number 171 .1 , inside another part of the element itself, indicated with the number 171.2. These two parts 171 .1 and 171 .2 do not come off because they are blocked by some pins, indicated with the number 171 .3. However, when a violent impact causes a strong traction force, which tends to slide off said two the parts 171.1 and 171.2, the pins 171.3 break and the joining element 171 opens, leaving the upright 110 no longer hooked to the ground connecting bar 161 (or 162). Depending on the number of pins 171.3 and their strength, it is possible to carry out a very fine adjustment of the programmed breakage of the junction element 171 .

Figure 6b shows a mechanism similar to that of Figure 6a, but even more articulated, in which the extraction of part 171.1 is opposed not only by a pin 171 .3, but also by an elastic deformation element, which absorbs part of the energy transmitted by the impact, transforming it into elastic potential energy, so that, in the event of collisions not so violent as to cause the breaking of the plug 171 .3, part of the energy is returned to the vehicle, contributing to its containment on the road.

The examples shown in the details of Figures 6a and 6b are evidently only two of many possible embodiment examples, and demonstrate how the invention is susceptible to a multitude of variants, which however must all be considered as different forms of implementation of the same invention.

These are examples that, in their substance (beyond the construction details), show how the fixing to the ground of a "guardrail" 101 according to the invention, which makes use of the presence of a longitudinal ground connection bar 161 , allows to significantly improve the performance characteristics of a "guardrail"; being able to obtain a safety barrier better fixed to the ground, with a better beneficial effect of the concatenation of the uprights 1 10, and predisposed for an adjustment, even very fine, of its mechanical performance.

Above all, this regulation can also be implemented in the field, and during installation, that is, in the only moment in which the general characteristics of the road can be realistically and fully assessed: dangerousness, ground holding, whether or not to accept road exits, and to what extent.

Again, with the aim of reiterating how the invention really lends itself to many interesting implementation variants, for the sole fact of exploiting the idea of an element of concatenation on the ground, through Figures 7a and 7b, it is yet illustrated another form of implementation of a safety road barrier according to the invention. The peculiarity of the embodiments presented in figures 7a and 7b consists in the particular conformation of the joining elements 171. The latter are essentially cables or, in general, elements flexible but resistant in tension, which wrap an upright 1 10 at the base and, in turn, they are hooked to said ground connection bar 161 , so as to hook the base of the uprights 1 10 which they wrap around, to the bar itself. The interest of this variant is given by at least two factors: a) the simplicity with which said joining elements 171 are made, also being able to choose among cables of different resistance; b) the fact that the hooking of said cables to said ground connection bar 161 can be exercised flexibly, by choosing hooking points also relatively distant from the upright: the two Figures 7a and 7b show, in fact, two different cases of installation, in which the joining elements 173 are hooked to the ground connection bar at different points.

The interest of point a) is due, in addition to the fact that simplicity is a value in itself, also to the possibility of creating an element predisposed to several programmed breaks in a very immediate way: it is enough to be provided, when installing, with different cables; or; having a single type of cable available, said joining elements 173 can be made with a simple cable, or with a double cable, or even with a greater number of cables, thus obtaining different resistances. The interest of point b) is due to the fact that, in this way, the chaining effect can be accentuated. In fact, in the event of impacts that stress in tension the cables of which said joining elements 173 are made, since the direction of traction on the ground connection bar 161 is oblique, the bar itself must oppose to a direction of displacement that has a component significant also in the direction parallel to the road, being able in this way to benefit from the holding of many more anchoring elements of the bar itself to the ground.

In fact, when said ground connection 161 is urged, in a specific point, to move towards the outside of the road, this stress is discharged predominantly on the anchor points closest to that point of stress. While, when said ground connection bar 161 is stressed to a displacement along a direction parallel to the direction of the road, this stress is discharged in a greater number of anchor points, the more inextensible the bar is (i.e., rigid in tension).

Finally, through Figures 8a and 8b, still another form of implementation of a safety road barrier according to the invention is illustrated, which represents an implementation variant of particular interest in the case of installations in which the roadway is located on a land, always indicated with the number 200, raised above the surrounding land. In these cases, which are quite frequent, the road substrate, under the asphalt surface 210 is a well compacted ground, but the embankment on the roadside is generally relatively fragile, just for the fact that there is little earth, towards the outside of the road: it is the typical case of a “narrow embankment’’, according to a quite used jargon among the insiders.

In Figure 8a there are highlighted some elements typical of this case: a raised ground 200, a road surface 210, and a series of uprights 1 10 infixed on the roadside (in Figure 8a it is shown only the footprint, of "C” shape, of these uprights 1 10). In the decidedly more common case, and with these elements alone, the 110 uprights are not firmly fixed to the ground, and in the event of an impact, even of medium violence, they are easily pulled from the ground, compromising the effectiveness of the safety barrier.

In these cases, the solution taught in the present invention can be implemented in a suitable form. The ground connection bar, always indicated by the number 161 , can perform the further function of improving the resistance of the ground 200, being suitably shaped like a metallic sheet bent so as to cover the ground along the edge of a road where a row of vertical uprights 1 10 are fixed to the ground individually, thus creating a sort of shell above this ground, of the so-called narrow embankment.

On this bent sheet metal, which actually constitutes said ground connection bar 161 , recesses can be made to measure, spaced with the same pitch as the uprights 1 10. Thanks to this shape, said ground connecting bar 161 , covers the ground well enough in correspondence with the narrow embankment, both between the uprights 1 10, and also on the external part, which is normally sloping, and which typically tends to give way on the occasion of impacts that hit the "guardrail".

As can be seen clearly in Figure 8b, in which said ground connecting bar 161 is positioned in its final position, it performs all the functions for which the invention was conceived and, in addition, consolidates the ground 200 opposing its local subsidence.

It is also noted that the configuration of Figure 8b offers other interesting advantages. In fact, thanks to the bending of the sheet metal carried out to follow the slope of the narrow embankment, it is facilitated the installation of anchoring elements 173, positioned obliquely, inclined so as to grip the ground towards the inside of the road, which, as is well known, it is generally well compacted soil. Furthermore, the installation of said anchoring elements 173 is facilitated by being able to work from outside the road.

Finally, it is also worth mentioning a further advantage, which may seem insignificant, but which is instead of particular utility in the context of ordinary road maintenance: in fact, said ground connecting bar 161 , covering the ground between the uprights, prevents grass from growing in this area, in a very uncomfortable position for mowing, also because it is located under a horizontal blockout bar 130.

Therefore, this particular conformation of said ground connecting bar (161 ), while representing an implementation choice recommended above all when the installation takes place on causeways, in which the barrier is installed on a small embankment which benefits from the consolidation effect generated by such a suitably bent ground connecting bar (161), it is an interesting option in general.

In fact, a ground connection bar (161 ) shaped as a flat and thin sheet metal, possibly bent so as to follow the conformation of the ground, and which acts as a covering, like a sort of shell, of the ground between the uprights 1 10 where it is installed a safety barrier, it is an implementation variant useful in all cases, as it always produces a beneficial consolidation effect and facilitates routine maintenance and roadside cleaning.

Concluding Remarks

In general, as seen from the previous description, the "road system", according to the present invention, lends itself to numerous implementation variants.

The provided description already highlights many of these variants. In fact, the possible forms for making the joining elements 171 are innumerable, just as the anchoring elements 173 can be implemented in many ways; and the ground connection bar 161 too, can be made with different conformations and with different mechanical resistances.

With strict reference to the anchoring elements 173, it is reiterated that their shape is not the subject matter of the invention, since the prior art proposes a great variety of such elements, which can largely be adopted as a suitable anchoring element for implementing the present invention, as well as the number and the pitch with which such anchoring elements are installed 173 can be decided in the field.

In fact, the inventive activity, in the case of the present invention, was exercised to conceive a reinforcement system of a "guardrail", applicable both to an already installed "guardrail" and to a newly installed "guardrail"; to optimally adapt it in the field, in order to manage all the main installation conditions. In fact, the installation conditions depend both on the type of terrain on the roadside and on the characteristics of the road itself, so the best choices in terms of safety may differ from case to case, depending on the stretch of road, and may also vary at a distance of a few meters.

Possible further variants may also depend on technological aspects concerning the individual components of the system, such as any additional consolidation and stiffening subsystems, but also on the materials that can be used to make each single part of the system.

Furthermore, the invention itself can be implemented in a minimal or superabundant way, for example, as already highlighted above, also the so-called ground connection bar 161 can be configured in different forges, it can be connected to the uprights 1 10, both on the inward side of the road as well as on the outward side of the road, in addition to the fact that it can also be implemented as an element physically divided into two parallel bars 161 and 162, each mounted on either side of the row of posts 110 that need to be connected.

All these innumerable variants can be implemented by the man skilled in the art without thereby departing from the scope of the invention as emerges from the present description and the attached claims, and besides being able to offer further advantages over those already mentioned, these variants can give rise the development of different installation methods.

Other areas of improvement may concern the presence of additional accessory elements, or tricks that promote installation efficiency.

In fact, the system, as a whole, can evolve towards a greater emphasis on the automation of the installation of "guardrails", and the installation/maintenance procedures can evolve towards highly automated processes, potentially executable by fully automatic machines. In fact, the invention lends itself to withstand considerable flexibility in the definition of the "guardrail" installation process.

The invention is therefore susceptible to further evolutionary efforts, capable of improving both the performance of the system described and the installation and/or maintenance procedures. Such developments, if not included in the present description, may be the subject of further patent applications associated with the present invention.

Claims

1. A road safety barrier (101 ) composed of a system of elements integrated together, which includes a set of vertical uprights (1 10) individually fixed to the ground in a row along the edge of a road, and at least one longitudinal blockout bar (130) composed of a sequence of horizontal segments connected to each other, sustained by said uprights (1 10), positioned at a height suitable for containing the exit from the road of a vehicle, and which connects together a sequence of uprights (110); moreover, said road safety barrier (101 ) also comprises a further longitudinal element (161 ), said ground connection bar (161 ), and laid over the ground; and said ground connection bar (161 ) is characterized in that it is suitable to connect a sequence of uprights (1 10) in a row, in order to concatenate them together and to increase the continuous chaining effect of the whole road safety barrier (101 ), and said ground connection bar (161 ) is also fixed to the ground.

2. Road safety barrier (101 ) according to claim 1 , wherein said ground connection bar (161) is connected to said uprights (1 10), by means of junction elements (171 ), and it is fixed to the ground, by means of anchor elements (173), infixed in the ground.

3. Road safety barrier (101) according to claim 2, in which said anchoring elements (173) are applied along the entire length of the ground connecting bar (161 ), and their number and their depth of insertion is variable, depending on the trait of road, thus offering a method of in-field regulating the firmness of the ground installation.

4. Road safety barrier (101 ) according to claim 1 , wherein said ground connection bar (161) is characterized by a mechanical strength and a weight lower than the strength and weight of said at least one longitudinal blockout bar (130).

5. Road safety barrier (101) according to claim 2, wherein said junction elements (171) are configured to be fixed to said ground connection bar (161 ), and to wrap around the base of an upright (1 10) so as to connect the bar (161 ) to the upright (1 10), and each of them is configured to vary its mechanical performance, so that it is subject to a programmed break when stressed by a traction force that tends to detach the upright (1 10), of which it wraps the base, from said ground connection bar (161 ).

6. Road safety barrier (101 ) according to claim 1 , wherein said ground connection bar (161) is laid externally with respect to the row of uprights (110), is fixed to the ground, by means of anchoring elements (173), infixed in the ground, and it is placed in abutment on the base of said uprights (1 10), thus offering a reinforcement to their installation, and thus contributing to their solidity when these are pushed towards the outside of the road due to an impact caused by an accident. Road safety barrier (101 ) according to claim 2, wherein said ground connection bar (161 ) is laid between the row of uprights (110) and the asphalt pavement of which the road surface (210) is made. Road safety barrier (101) according to claim 7, wherein, in addition to said ground connection bar (161 ) laid between the row of uprights (1 10) and the asphalt paving of which the road surface (210) is made, there is also a second ground connection bar (162) placed externally with respect to the row of uprights (1 10). Road safety barrier (101) according to claim 5, wherein said junction elements (171 ) are cables or, in general, flexible but tension-resistant elements, which wrap an upright (110) at the base and, in turn, each of said junction elements (171) is attached to said ground connection bar (161 ) in two attachment points which are relatively distant from the upright (1 10), of which it wraps the base, in such a way that, when said junction elements (171 ) stretch as a result of an impact that tends to move the upright (1 10), of which it wraps the base, away from said junction bar (161 ), said bar (161 ) must oppose to a movement that has a significant component also in the direction parallel to the road. Road safety barrier (101 ) according to claim 1 , wherein said ground connection bar (161 ) is shaped as a flat and thin plate, possibly bent so as to follow the shape of the ground along the edge of a road, where said row of vertical uprights (1 10) are individually fixed to the ground, creating a sort of shell above this ground.