Guardrail

1. A guardrail ( 1 ) comprising a number of vertical supporting posts ( 2 ) fixed successively to the ground along the edge of a road; and one or more longitudinal members fixed successively and substantially horizontally to said vertical posts ( 2 ) to form a longitudinal transverse retaining member ( 4 ) extending along the edge of the road, at a predetermined height off the ground;

at least one of said longitudinal members comprises a rigid, controlled-deformation strip bent back on itself to form a tubular, complex-section body extending, substantially parallel to and at the predetermined height off the ground, from one of the vertical posts ( 2 ) to another of the vertical posts, and to define at least a first ( 3 ′, 13 ″) and a second ( 3 ″, 13 ′) longitudinal portion adjoining each other;

the first longitudinal portion ( 3 ′, 13 ″) of the strip being bounded laterally by a first lateral edge ( 3 a , 13 a ) of said strip, being positioned facing the vertical posts ( 2 ) of the guardrail, and being substantially S-shaped, so that the first lateral edge ( 3 a , 13 a ) of said strip is located close to the top of the vertical posts ( 2 ), and a boundary line with the second longitudinal portion ( 3 ″, 13 ′) of said strip is located below the first lateral edge ( 3 a , 13 a ) of the strip ( 3 , 13 ), at a predetermined minimum height (h) off the ground;

the second longitudinal portion ( 3 ″, 13 ′) of the strip being substantially C-shaped covering said first longitudinal portion ( 3 ′, 13 ″), from the boundary line to the first lateral edge so that a second lateral edge ( 3 b ) of the second longitudinal portion rests on the first lateral edge ( 3 a , 13 a ) of said strip.

2. A guardrail as claimed in claim 1 , characterized in that the rigid strip forming said longitudinal member is fixed firmly to said vertical posts ( 2 ) at the longitudinal rib formed by superimposing the first lateral edge ( 3 a , 13 a ) of the strip and the second lateral edge ( 3 b ) of the second longitudinal portion ( 3 ″, 13 ′) of the strip ( 3 , 13 ).

3. A guardrail as claimed in claim 1 , characterized by also comprising retaining lines ( 11 ) having ends secured to the ground, extending substantially parallel to the ground, alongside the longitudinal members forming said longitudinal transverse retaining member ( 4 ), and sliding inside through holes formed in the vertical posts ( 2 ) of the guardrail.

4. A guardrail as claimed in claim 3 , characterized by also comprising a number of tensioning devices ( 12 ) arranged along the retaining lines ( 11 ) and designed to adjust the tension of the retaining lines ( 11 ) to which the tensioning devices are fitted.

5. A guardrail as claimed in claim 3 , characterized in that said retaining lines ( 11 ) are made of synthetic material.

6. A guardrail as claimed in claim 5 , characterized in that synthetic material comprises nylon or carbon.

7. A guardrail as claimed in claim 1 , characterized in that at least one of said vertical posts ( 2 ) comprises a bar ( 9 ) fixed partly and substantially vertically into the ground; and an elastic connecting bracket ( 10 ) interposed between said bar ( 9 ) and said longitudinal member.

8. A guardrail as claimed in claim 7 , characterized in that said elastic connecting bracket ( 10 ) is located at the top of said bar ( 9 ).

9. A guardrail as claimed in claim 1 , characterized in that said rigid strip also comprises a third longitudinal portion ( 13 ′″) adjoining said second longitudinal portion ( 13 ′), on the opposite side of said first longitudinal portion ( 13 ″); said third longitudinal portion ( 13 ′″) being bounded laterally by a second lateral edge ( 13 b ) of said strip, and being substantially C-shaped, so that said second lateral edge ( 13 b ) of the strip is located on the opposite side of the vertical posts ( 2 ) of the guardrail to the first longitudinal portion ( 13 ″) of the strip, and is substantially aligned with the boundary line between said first ( 13 ″) and said second ( 13 ′) longitudinal portion of the strip.

10. A guardrail as claimed in claim 1 , characterized in that said rigid strip is made at least partly of composite material.

11. A guardrail as claimed in claim 8 , characterized in that said composite material comprises at least one layer of appropriately interwoven fibers comprising one of glass carbon, or aramid embedded in an epoxy resin matrix.

12. A guardrail as claimed in claim 1 , characterized in that said vertical posts ( 2 ) are made at least partly of composite material.

13. A guardrail as claimed in claim 1 , characterized in that the boundary line between said first ( 3 ′, 13 ″) and said second ( 3 ″, 13 ′) longitudinal portion of the strip is located at a minimum height (h) of 1 to 10 centimetres off the ground.

14. A guardrail as claimed in claim 1 , characterized in that the first lateral edge ( 3 a , 13 a ) of said first longitudinal portion ( 3 ′, 13 ″) and the second lateral edge ( 3 b ) of said second longitudinal portion ( 3 ″, 13 ′) of said strip are fixed to each other by a number of through rivets ( 5 ).

15. A guardrail as claimed in claim 14 , characterized in that said through rivets ( 5 ) are made of an elastically deformable material.