EP1994228A1

EP1994228A1 - Yielding connector for poles and posts

Info

Publication number: EP1994228A1
Application number: EP07709201A
Authority: EP
Inventors: Kjell Arne Malo
Original assignee: Euromast AS
Current assignee: Euromast AS
Priority date: 2006-01-23
Filing date: 2007-01-19
Publication date: 2008-11-26
Also published as: NO324580B1; WO2007084009A1; NO20060336L

Abstract

Yielding connecting device for poles at roadways, wherein the upper end of a base (8) and the lower end of a pole (9) each carry or are integrated with a mounting plate (1, 2). The mounting plates are connected with at least one pressure element (3) maintaining the mounting plates at a predetermined distance, and at least one tension element (4) bearing against the mounting plates to apply an axial prepressure to pressure element and keeping the mounting plates together. The pressure element (3) is an extended element with a narrow contact surface relatively to the total surface of the extended element, to each mounting plate, to provide a stilt effect at a relative sideward movement of the mounting plates. The connecting device is provided for, at a collision against the pole (9) with a vehicle, to have a relative sideward displacement of the mounting plates causing a disintegration of the connecting device. The tension elements (4) are arranged in recesses (5) or inner corners of the mounting plates.

Description

Yielding connector for poles and posts

The invention relates to a connecting device as stated in the introductory part of claim 1 , for supporting structures such as poles, posts and the like, for use at roadways. Further the invention relates to such support structures which are integrated to such a connecting device. Such connecting devices for poles/posts and the like can be used for traffic information and/or lighting purposes, for example for traffic signs, light signals, antennas, full-size or half-size portals, street lighting, road railings and other components intended to break or be yieldable and absorb shock energy according to given criteria upon accidental collision.

Background

Light poles, signs etc. are currently part of a traffic environment. Typically such constructions are mounted on foundations of concrete, steel or the like and have to be dimensioned for tolerating both its own weight and natural loads like snow and wind and other loads. This can result in very unfavourable characteristics in view of rigidity and load capacity upon collision therewith by a vehicle. The increasing importance of road safety in many countries means that one strives for the traffic environment to develop in such a way that it results in passive safety to the road users. In this connection a European norm for checking and authorising of yieldable road equipment has been introduced: EN 12767 Passive safety of support structures for road equipment. This standard requires that traffic equipment has to be yieldable and mainly energy absorbing. Yieldable poles are classified according to their energy absorbing characteristics in the following classes: HE: High energy absorbing LE: Low energy absorbing v. NE: Not energy absorbing

In the HE-class a vehicle will be completely cushioned and retarded in a controlled manner to a low exit velocity. In the LE-class the automobile will also be retarded in a controlled manner to an exit velocity, without the severe requirements of the HE-class. In the NE- class there is no requirement for energy absorption and retardation of cars, however, the structure is required to be cut off immediately at an impact and shall skid away. This usually is called a break-away-system. For each of the NE, LE and HE-classes, the same release system at the base may be used, but the energy absorbing systems LE and HE normally connect the poles to provide sufficient energy absorption. Yielding pole structures are needed for other transport systems, as antenna and lighting systems at airports and also in other transport systems.

Prior art Norwegian patent specification 160458 describes an extruded pole with a casing and rods adjusted for structural interaction and which are interconnected so that the connection is disrupted when the post is exposed to a local stress of a predetermined magnitude in the transverse direction. In the corners inner grooves are arranged, which form fracture lines, and at least on some of the sides of the casing are arranged open channels divided by reeds projecting into them. The rods are attached to the channels, preferably under pretension of the clamping reeds. With this solution the rods and the casing interact for the handling of static loads and have no substantial effect at a collision. The rods have no axial pretension.

There are known a number of break-away systems in which the deformations are concentrated in various designs of bolts attached to a base plate as shown in US-patent specifications 3.637.244, 3.951.556, 3.967.906 and 6.056.471. Common to these designs is that they do not separate rigidity and torque and shearing strength. Consequently the areas which are reduced to control the capacity also cause reduced rigidity and strength for other loads, as well as presenting substantial risk of fatigue. Canadian patent specification 973677 (Shewchuck) also discloses a break-away system. This system consists of multiple connector tubes of a brittle material, with crack grooves and internal threads in both ends. Each end of the tube is fastened to a plate with a threaded bolt. The system collapses when the tube is disrupted along the crack grooves due to the bending load of the bolts. The bending capacity of the tubes is limited and the bolts remain intact. A pretension of the tubes is not possible, because no separate tension and load elements are used. There is no "stilt effect" due to the tubes, because the bolts will provide complete bending rigidity at the ends of the tubes. It will not be possible to increase the axial rigidity or the bending rigidity of this connector by increasing the number of tubes, without increasing the shear strength and the bending strength as the tubes are fastened with bolts at the ends. Further disadvantages of this structure are described in US patent specification 5,855,443 (Faller et al. 1999).

From US patent specification 4.923.319 (Dent 1990) there is known a connecting device with two mounting plates which are held together by end-to-end bolts with a preformed stress point. This point is intended to break at an impact, but it is also liable to fatigue. From US patent specification 5.855.443 (Faller et al. 1999) there is known a corresponding connection device which also is provided with two mounting plates which are held together by end-to-end bolts. The only difference over 4.923.319 (Dent 1990) is that around each bolt between the mounting plateses two loose shearing rings with a mutual surface of contact are mounted. At a collision the loose rings ensure collapse by the bolt being sheared, which requires a small distance between the mounting plates. A disadvantage of the design with two loose shear rings (US 5,855,443 Faller) is the vulnerability to friction. A connecting device is desirable, which is not vulnerable in regard of friction, due to the use of long, parallel load elements with "stilt effect", which are overturned when the shear load exceeds a predetermined value.

In US patent specification 6,210.066 (Dent 2001) a break-away-joint is described, with a through bolt with a preformed stress point. Vertical legs or legs provided by the side walls of the end connection of the pole or suitable side walls are rigidly connected with the upper end connection to the pole and slidably engage to the lower end connection. This structure can not be biased due to the sideward frictional forces created.

A common drawback for said known units is that the same structural element provides stiffness and strength for all deformation modi and that these known units do not provide satisfactory control of strength and stiffness.

In US patent specification 3,912,404 (Katt 1975) a pole structure is described, in which the pole is divided and connected with a breakable connecting device and an anchoring device which is not further described. This anchoring device is to be fastened with at least one bolt through the wall of the pole and correspondingly at the end of the pole to the ground. It is a feature of this anchoring device that it is designed as a strip with a longitudinal slot with one or more bolts at each end, the bolts being fastened to the wall of the pole. The slots allow for a restricted deformation both transversally and longitudinally to the slot. When using mounting plates, this structure will not be suitable. The patent requires the fastening bolts to protrude through the side walls of the pole.

In US patent specification 4,269,384 (Saeed 1981) a structure with breakable connections is described. One such connection (claims 14 and 15) consists of splice bolts, extended channels or claws with narrower mouth openings than the bolt diameter and a spacer between the tubular ends to be spliced. The claws are attached to the tubes to be connected. The intermediate element consists of a thin tubular element which is made frangible by longitudinal slits or holes. This design has its stiffness due to the larger cross section of the frangible tubular element relative to the tubes to be connected. In case the cross sections of the tubes do not coincide, intermediate plates have to be used, which can be welded, e.g. to the intermediate element without losing the function of the new design. This is held together by the splice bolts, but said bolts cannot increase the rigidity of the connection, as this would break down the weakened tubular element. This function may be used by making the connection break down due to pressure making the weakened tubular element break. The outer forces providing such pressure may be bending or compressive forces. The present technical problem needs the highest possible bending strength and the release of the connecting device by low shearing forces, but not by compressive forces. This design will not solve the present technical problem.

The most used break-away system is probable the system known as "slip-base" or "Texas Universal Triangular Slipbase System (TUTSS)". This is commonly used in Europe and is described in the catalogues of most traffic pole supplies. Typical slip base options are described e.g. in US patent specifications 6,868,641 (Connor 2005) and 6,540,196 (Ellsworth 2003). It consists mainly of two stiff triangular planar plates, one of which is connected to a base and the other with the pole. The triangular shear plates are interconnected with three bolts, one at each corner. The bolts are arranged in slots which are outwardly open and have an angle of opening allowing the expelling of the bolts from the slot if one plate is moved relatively to the other parallel to the plane of the plates with a shearing movement. Between said shearing plates a thin plate of Teflon (trademark) or a similar material may be arranged for two reasons: to reduce the friction between the plates and/or prevent the displacement of the bolts during normal use. The last requirement is based on the need for the untightened bolts to let the slip base function upon a collision occuring. Thus the bolts should not have pretension. One shear plate has to slide against the other and the bolts have to be moved completely out of the slots before the shear plate with the pole is released. This requires a almost pure shear load on the pole, because other loads have a tendency to restrain sliding. This has caused deficiencies in the slip base designs due to the difficult release. Particularly when the point of impact is at a distance from the plane of the slip base, a moment load has occurred, increasing the axial load of the tensioned bolts, as well as increased contact friction between the shear plates, locking the total slip base, without releasing the pole. Ellsworth (US 6,540,196 2003) seeks to reduce the friction by mounting a plane, horizontal ball bearing between the mounting plates, wherein the balls are arranged in a housing consisting of holes in an intermediate plate, e. g. of polypropylene. This proposal may reduce the friction, but does not alleviate the problem.

Another disadvantage of slip bases is that they are not suitable as release mechanism for poles designed for energy absorption (HE or LE) because it will not allow rotation of the foot of the pole due to the impact between said shear plates, because the lack of free space there between. There are also alternative slip base designs, with e.g. two square, planar plates with four bolts, preferably one in each corner. Reference is had to the website of US Department of Transportation, Federal Highway Administration. These slip base designs with a different design of the plates and different number of bolts have the same deficiencies as the triangular design with three bolts.

From Norwegian patent specification 316629 there is known a design with two planar plates divided by longitudinal pressure elements with the extended pressure bodies arranged perpendicularly to the plates. The pressure elements, which are maintained in position by pretension elements arranged in openings in the plates, allows a stilt or rolling function which is independent of the friction. The pressure elements can be kept together or in situ by a shear element, e.g. a holding matrix, surrounding ribbons or by the pressure elements which are releasably connected. This design can be used both for NE, LE and HE poles because the distance between the plates is made sufficient to allow the upper plate to rotate after release of the connection. The mounting of the tension elements (which may be pretension bolts) through openings may, however, involve considerable inconvenience as the bolts have to be fractured and/or torn out to release the connecting device and have the upper base plate with the pole mounted, released. This implies strong restrictions in the use of bolts and thus in the static capacity of the connecting device.

Object

The main object of the invention is to provide a connecting device between a base and a carrying structure, such as a mast or a pole or similar, as mentioned above, respectively a complete carrying structure, which is considerably improved in respect of yielding and the capacity for energy absorption and one or more of the disadvantages mentioned above.

Particularly it is an object to provide a connecting device with maximum and predictable strength to unintended collision impact. By having a defined maximum releasing strength as well as providing a non-moment connection after release, e.g. by a collision impact, and provide an axial anchor at the foot point, the connecting device can provide an important additional function, providing energy absorption and retarding of a car or another vehicle. The invention should also make the carrying structure comply to the requirements for yielding poles and/or the requirements for energy absorption for impact loads, as defined e.g. in EN 12767.

A further object is that the connecting device should not reduce the rigidity of the carrying structure or limit the required load capacity of the carrying structure at normal loads, such as wind. It should be simple and low cost in installation and maintenance. It is also important that the performance is predictable, reliable and repeatable over a long period of time. The Invention

The invention is a connecting device to be mounted between a pole or a similar structure and a base. The invention is stated in claimi , while claims 2-11 states particular advantageous features or modifications, claim 12 defines a connecting device with an anchoring device to be used with energy absorbing poles, and claim 13 relates to a compound carrying structure. Further details of the invention are mentioned in the succeeding description of embodiments, but the invention is not restricted thereto.

In this specification, "carrying structure" is used as a common term for a carrying element rising or projecting from a base, the connecting device and the base. The rising or projecting element is in the following simply referred to as a "pole". Thus the term "pole" may cover any vertical, horizontal or inclined projecting element which may be arranged at a roadway as independent or integrated carrying means. The pole can have various embodiments, such as a pillar for a road sign, a light mast or a non-vertical element carrying a road fence or another road guard. By "connecting device" is meant the parts connecting the base and the pole, being separate parts or being totally or partly integrated in the elements to be connected. By "anchoring device" is meant the parts providing the anchoring between a base and the pole, being a wire, a cable or another bendable member. By "base" is meant any structure which the pole can be connected to.

The invention allows the separation of all important functions in respect of strength and rigidity for a yielding carrying structure. The invention is provided with separate structural elements to ensure the different load effects from normal loads, such as wind and gravity, as well as impact, e.g. upon the collision of a vehicle. By changing the dimensions of the various structural elements, minimum and maximum strength and rigidity may be substantially independently designed. By integrating the different parts with individually adapted dimensions an integrated, yielding connecting device is created, with known combinations of qualities and predictable performance. The invention may be mounted both on new carrying structures, as masts and poles, and on existing structures, with a separate base or similar carrier.

The composite yielding connecting device comprises two or more mounting plates which are connected by elements consisting of one or more pressure members, one or more tension members, one or more shear members and zero, one or more anchoring members for axial load, and various bolts, nuts, washers etc.

The invention combines the advantageous property which is also utilized in the slip base systems, that the bolts (the tension members) can be released without breaking, tearing or breaking, by being mounted in slots which are open ended at the exterior. The invention will also allow for mounting the tension elements in slots being open to an interior opening. Further, the invention will utilize the advantageous properties known from Norwegian Patent Specification 316629 by using one or more extended pressure elements providing a stilting function between said mounting plates and thus no dependence on friction for relative movement of said plates in their plane. The resistance against this stilt effect is determined by the length of the pressure elements, by the form of the surface of contact against the mounting plates and the degree of tension of the tensioning elements.

Example

The invention is described in the following with reference to the drawings, wherein Fig. 1 shows schematically the disintegration principle of the connector (vertical section),

Fig. 2 shows a simple embodiment of the invention with an external recess (vertical and horizontal section,

Fig. 3 shows an embodiment with three tensioning elements and three groups of pressure elements,

Figure 4 shows an embodiment with four tensioning elements and four groups of pressure elements,

Figure 5 shows a mounting plate for mounting three tensioning elements in internal openings, Figure 6 shows a mounting plate for mounting four tensioning elements in internal openings,

Figure 7 shows a connecting device with an anchoring device mounted thereto.

The invention is show schematically in Figure 1 , illustrating the invention with three vertical sections through the yielding connecting device, with a situation of normal use to the right, with a collision situation in the middle, and with the succeeding disintegration or release of the connecting device to the left. Upon movement of one mounting plate 2 in a plane of the plate relatively to the second mounting plate 1 , a pressure element 3 (or the pressure elements) depending on the geometrical dimensions, imply a small increase in the distance between the mounting plates 1 , 2 and thus resistance against movement due to the increased load on the tension elements 4. This and the pretension from the tension elements 4 provides the connecting device with the desirable stiffness in the normal state of use. Maximum horizontal shear resistance is attained approximately when the plates 1 , 2 have a maximum distance and this maximum release force is about in inverse ration to the length of the pressure elements 3 and can thus be made arbitrarily low. This state is shown in the middle of Figure 1. The horizontal movement of the plates beyond the state of the middle part of figure 1 involves a reduction of the distance between the plates 1 and 2 and the tension elements 4 and the pressure elements 3 will be slanted between the plates 1 , 2 at about the same angle. This will involve an increase in the tension of the tension elements 4; at least the horizontal force component will increase due to the increase slanting. The horizontal pressure-force component of the pressure element 3 will, however, also increase correspondingly, bringing no substantial change in the horizontal forces and thus the external force needed for ensure a relative horizontal movement will not be influenced by the slanting of the tension elements 4 and of the pressure elements 3. Further displacement brings further slanting of the pressure elements 3 and thus a further reduction of the distance between the plates, but no change in the resulting horizontal forces. An additional external moment will not change this, as it brings no net force contribution in either direction, and the friction has no effect.

When the distance between the plates 1 , 2 is reduced such that no force is on the tension elements, the bolts will be released, not by being displaced out of the slots by forces from the upper plate as for a slip base connecting device, but by the distance between the plates 1 , 2 being so reduced that the tension elements 4 are tension free and fall out of the slots 5 as shown at the left part of Figure 1. Normally, the pressure elements 3 will commence sideward sliding due to the slanting, and this will result in the connecting device to collapsing or disintegrating. A slip base structure can not conduct this movement, as there is no distance between the mounting plates. A slip base will also lack a mechanism for eliminating the effect of moment as described above for this invention. For a non energy absorbing pole (NE) this will be sufficient. For energy absorbing poles the invention additionally requires an anchoring device, as chains, wires, clamps, or another linked device taking axial forces, but insignificant moments. The pressure elements 3 should be chosen sufficiently long to allow for a necessary rotation of the mounting plates for energy absorbing poles.

Figure 2 shows a more detailed embodiment of the invention, with triangular mounting plates 1 , 2 which in vertical section corresponds to the schematic drawings of Figure 1 and the function is thus described. Figure 2 shows the upper mounting plate 2 being attached to a pole 9 and the lower mounting plate 1 being attached to a base 8, which may be a tube pressed into the ground or another pole. The two mounting plates 1 and 2 are connected by pressure element 3 and three tension elements 4. There is no anchoring device to make the structure function as a NE structure. The pressure element 3 has circular and plane contact faces 6 being parallel to a plane of the mounting plates 1 , 2 and the pressure element 3 has constant cross section 7 over its length. The three tension elements 4 are mounted in slots 5 arranged at the edge of the plates, being present in both the upper mounting plate 1 and the lower 2. A washer may be added if necessary.

Figure 3 shows an alternative embodiment of the device shown in Figure 2, being more suitable for NE light poles, being provided with holes 14 in both mounting plates 1 , 2 to allow the pulling of light cables in the base tube 8, through the mounting plates 1 , 2 and into the pole 9. The pressure elements 3 are grouped in groups of three. These groups are arranged as close to the tension elements 4 as possible. The design of each of the pressure elements 3 may be as shown in Figure 2. Multiple pressure elements 3 are grouped together with enclosing ribbons, or by an enclosing tubular structure. Such an enclosing structure may also attach them to a tension element 4. This may be suitable for mounting, corrosion, esthetics or to avoid wrong mounting. It may also be practical to arrange the pressure elements in a matrix of a group of pressure elements which are to be included with a tension element. Manufacturing considerations will mainly decide such choices, and a common, easily releasable holding matrix for all elements connecting the mounting plates is preferable. Such holding matrixes are not shown in the drawing, as they are subordinate to the function of the invention.

Figure 4 shows, similar to Figure 3, an alternative of the connecting device which may be suitable for light poles or other poles with electrical cables, due to the holes 14 of the mounting plates 1 , 2. In this case, a squared base of concrete or steel 8 is used, which is connected to the lower mounting plate 1 by bolts 15 which are provided with washers and nuts. The mounting plates 1 , 2 are geometrically different and are connected with four tension elements 4 realized by bolts with head 11 and nut 12 and further with oblong washers 13. The tension elements 4 are arranged in external recesses or slots 5, which are located at the corners of the upper mounting plate 2, and at the sides of the lower mounting plate 1. The pressure elements 3 are arranged in groups as described for Figure 3.

Figure 5 shows a horizontal section through a connecting device with a triangular mounting plate. This design can be used both for the upper mounting plate 2 and the lower 1. In this case, the tension elements 4 are arranged in internal slots 5 provided by furnishing a triangular opening 14 in the mounting plates 1 , 2, and the internal corners are utilized as recesses 5. This structure can not be used for slip base systems, as there is no distance between the mounting plates and inner bolts will imply a locking. This creates no problem for the invention, as the distance between the plates will allow the bolts to stay away from the plates at the release of the connecting device. In this embodiment, six separate pressure elements 3 with square section, which may well be grouped close to the tension elements 4. The tension elements may be provided with head and nut 11 , 12, and washers if desirable. The number of openings'! 6 are arbitrary according to need, adapted to be used for e.g. attaching the lower mounting plate 1 to a base 8, and the upper mounting plate to e.g. a triangular girder pole.

Figure 6 shows a circular mounting plate 1 or 2, with a squared opening 14. The restrictions to the geometrical design of the mounting plates are minor, as long as there are internal and/or external slots 5 which can be used as attachment points for the tension elements 4. The two recesses or internal corners or recesses 5 used for a tension element 4 should mainly have the same direction of the opening angle. In this embodiment, the connection device can be arranged inside a pole with a circular section and the dimension of the circumference 17 of the plate to weld the pole to the circumference or on the upper side of the plate. In this embodiment, the mounting plate 1 , 2 can be attached to the pole 9 or the base 8 with e.g. four bolts 15 with washers and nuts engaged through openings 16 in the mounting plates 1, 2. The mounting plates may have multiple openings 16 which may be used for other purposes or other equipment or for attaching a anchoring device, which may be of interest for energy absorbing poles.

Figure 7 shows the embodiment of Figure 4, but with an additional anchoring device according to claim 12. The anchoring device consists of a chain with one link, realized by two half links 18, 19. The two half links 18, 19 are catching each other and provided with threaded ends. They are attached to the mounting plates 1 , 2 respectively through openings 16 with e.g. nuts 20 and washers 21 , alternatively by welding. Upon a collision occuring the anchoring device does not influence the connecting device before it has lost its bending stiffness and is primarily intended for energy absorbing structures.

Properties For the connecting device to achieve sufficient rigidity at normal loads, such as wind, the pressure elements 3 are tensioned by the tension elements 4. The rigidity may thus be increased without increasing the strength. This separates the strength and rigidity properties from the properties upon unintended collision occurring. Upon a collision of a vehicle with the carrying structure the function is as follows: • The connecting device will disintegrate upon a predetermined size of the shear force at the connecting device being exceeded.

• The connecting device provides a substantially moment free link provided that the anchoring device is arranged according to claim 12.

• Provided that the connecting device has an integrated anchoring device, the energy absorption will mainly be effected through deformation work of the pole, said connecting device being active to provide rotation and displacement of the foot to remain as intended at collision. This will depend on class (HE, LE) and the pole properties.

• By excluding the anchoring device, the opportunity to absorb large energies in the pole and the connecting device provides a NE-system (non energy absorbing).

Properties gained relative to prior art technology:

• Substantially lower force needed for disintegrating the connecting device, providing higher safety for passive systems at roadways.

• The static strength can be increased without increasing the release force

• The structural strength regarding bending and torsion can be increased without increasing the release force.

• Substantially independence from the material properties at a collision provides for high predictability

• Independence of frictional properties and consequences of corroding at collision.

• No locking of connecting device when hit at a high altitude. • Independence of vehicle hitting point provides higher safety.

• Energy absorbing (HE, LE) and non energy absorbing pole systems optional

• Low costs of mounting, repair and maintenance.

The function of the connecting device may be selected by changing minor details in the embodiment. The embodiment of the connecting device may be altered by combining the different elements so they are joined with relatively great independence. The connecting device has a distance between the mounting plates 1 , 2. This distance should be chosen up to half the diameter of the upper mounting plate to provide an optimal result as a moment free link for energy absorbing systems.

Claims

1. Yielding connecting device for masts and poles, particularly at roadways, wherein the upper end of a base (8) and the lower end of a pole (9) each carry or are integrated with a mounting plate (1 , 2), which mounting plates (1 , 2) are connected with at least one pressure element (3) maintaining the mounting plates at a predetermined distance, and at least one tension element (4) bearing against the mounting plates (1 , 2) to apply an axial prepressure to the at least one pressure element (3) and keeping the at least one pressure element (3) and the mounting plates (1 ,2) operationally together, the at least one pressure element (3) being an extended element with a narrow contact surface relatively to the total surface of the extended element, to each mounting plate (1 , 2), to provide a stilt effect at a relative sideward movement of the mounting plates (1, 2), said connecting device being provided for, at sudden sideward impact above a certain level, as at a collision against the pole (9) with a vehicle, to have a relative sideward displacement of the mounting plates (1 , 2) causing a disintegration of the connecting device, characterized in that the tension elements (4) are arranged in recesses (5) or inner corners (5) of the mounting plates (1 , 2), which are open outwards or toward an inner opening (14) allowing the introduction of at least one tension element (4), and that the recesses (5) or inner corners (5) of the mounting plates (1 , 2) which are used for the one or each tension element (4) have generally cooriented openings in the plane of the mounting plates (1 , 2).

2. Connecting device according to claim 1 , characterized in that the pressure element (3) or elements are arranged symmetrically to the tension element (4) or tension elements.

3. Connecting device according to claim 1 or 2, characterized in that pressure elements (3) are arranged in groups between the mountings plates, each group being subjected to pressure from one or more tension elements (4).

4. Connecting device according to claim 1 - 3, characterized in that two or more separate, parallel pressure elements (3) are maintained releasably together with a holding matrix or a surrounding tube with one or more voids in an arbitrary cross section, or are mutually connected with a ribbon or another connecting means, the holding matrix or connecting means comprising one or more tensioning elements (4).

5. Connecting device according to claim 1 , characterized in that the contact surfaces (6) between the mountings plates (1 , 2) and the pressure elements (3) are circular, elliptic or polygonal.

6. Connecting device according to claim 1 and 5, characterized in that the cross section (7) of the pressure elements (3) is constant over the length, with a shape substantially equal to the projection of the contact surface (6) between the mounting plates (1, 2 ) and the pressure elements (3).

7. Connecting device according to claim 1 and 5, characterized in that the contact surface (7) of the pressure elements (3) is different from the contact surface (6) against the mounting plates (1 , 2).

8. Connecting device according to claim 1 and 5, characterized in that at least one of the mounting plates (1 , 2) has grooves or recesses making contact surfaces (6) for the pressure elements (3), which may be completely or partly curved or blunt.

9. Connecting device according to claim 1 and 5, characterized in that the mounting plates (1 , 2) may be different in regard of geometrical shape and connection to the pole (9) and the base (8), and the mounting plates (1 , 2) may have one or more openings and non- planar areas.

10. Connecting device according to claim 1 , characterized in that the tension element or elements (4) are bar-shaped and designed to provide a permanent bias.

11. Connecting device according to claim 1 and 10, characterized in that the tension element or elements (4) is/are provided with connecting means against the mounting plates (1 , 2), which may include a head (11), increased diameter, threads and nuts (12), washers (13) or similar.

12. Connecting device according to claim 1 , characterized in that one or more anchoring devices, such as wires, cables, brackets, ribbons, ropes, chains, may be anchored to the lower mounting plate (1) or to a base (8) and to an upper mounting plate (2) or a pole (9), and which maintains a connection substantially without a moment between the mounting plates (1 , 2) or between a pole (9).

13. Carrying structure for use at roadways, characterized in that it comprises one or more bases (8), one or more tubular poles (9) with open section or a girder pylon, or a combination thereof, and which is connected to the base (8) with one or more connecting device according to one or more of the claims 1 - 12.