Guardrail terminal
Guardrail, guardrail terminal, and support post designs that improve control of a vehicle during collisions are described. The disclosed designs also reduce the likelihood of intrusion into vehicle systems and the occupant compartment(s). Embodiments include folding and/or flattening of the guardrail and controlling the folded and flattened guardrail to avoid intrusion into the vehicle. Other embodiments include containing the guardrail in an impact head of a guardrail terminal, which also avoids vehicle intrusion.
1. A guardrail assembly, comprising:
a w-shaped guardrail extending longitudinally, the w-shaped guardrail including a first, upper end and a second, lower end, each of the first, upper end and the second, lower end extending from the w-shaped guardrail in a first direction that is horizontally transverse to a longitudinal direction; and
a guardrail terminal having a first end and a second end, the guardrail terminal configured to receive the w-shaped guardrail at the first end of the guardrail terminal, the guardrail terminal including a deflector positioned between the first end of the guardrail terminal and the second end of the guardrail terminal, the deflector configured to fold the w-shaped guardrail such that the first, upper end and the second, lower end of the w-shaped guardrail are repositioned from extending in the first direction to extending in a second direction that is horizontally transverse to the longitudinal direction while the w-shaped guardrail is within the guardrail terminal, the second direction being is opposite to the first direction.
2. The guardrail assembly of claim 1 , including a downwardly oriented opening positioned between the deflector and the second end of the guardrail terminal.
3. The guardrail assembly of claim 1 , the guardrail terminal including a feeder chute positioned to extend from the first end of the guardrail terminal, and the feeder chute is configured to receive the w-shaped guardrail.
4. The guardrail assembly of claim 3 , the guardrail terminal including a throat positioned between the feeder chute and the second end of the guardrail terminal, the feeder chute has a first width, and the throat has a second width that is greater than the first width, and the second width of the throat increases with distance from the feeder chute.
5. The guardrail assembly of claim 1 , wherein the deflector extends a first width from an interior wall of the guardrail terminal at a first end of the deflector and a second width greater than the first width from the interior wall of the guardrail terminal at a second end of the deflector upstream from the first end.
6. The guardrail assembly of claim 5 , including a feeder chute positioned to extend from the first end of the guardrail terminal, and the feeder chute is configured to receive the w-shaped guardrail.
7. The guardrail assembly of claim 6 , wherein the deflector is angled from an end of the deflector that is closest to the feeder chute to an end of the deflector that is closest to the second end of the guardrail terminal, and the deflector is widest at the end of the deflector that is closest to the second end of the guardrail terminal.
8. The guardrail assembly of claim 1 , wherein the guardrail terminal includes a downwardly oriented opening positioned between the deflector and the second end of the guardrail terminal.
9. The guardrail assembly of claim 1 , wherein the w-shaped guardrail initially includes three reversals of direction along a transverse length of the w-shaped guardrail, and after the first, upper end and the second, lower end of the guardrail terminal are repositioned, the w-shaped guardrail includes only a single reversal of direction and is no longer in the w-shape.
10. A guardrail terminal, comprising:
a first end configured to receive a w-shaped guardrail including a first end and a second end, each of the first end and the second end of the w-shaped guardrail extending in a first direction;
a second end,
a downwardly oriented opening positioned adjacent the second end of the guardrail terminal; and
a first deflector positioned between the first end of the guardrail terminal and the downwardly oriented opening, the first deflector configured to fold the w-shaped guardrail such that the first end and the second end of the w-shaped guardrail are repositioned from extending in the first direction to extending in a second direction that is opposite to the first direction.
11. The guardrail terminal of claim 10 , including an upwardly oriented opening positioned on an opposite side of the guardrail terminal from the downwardly oriented opening.
12. The guardrail terminal of claim 10 , including a feeder chute extending from the first end of the guardrail terminal, and the feeder chute is configured to receive the w-shaped guardrail.
13. The guardrail terminal of claim 10 , including an upper deflector positioned within the guardrail terminal on a first side of the first deflector and a lower deflector positioned within the guardrail terminal on an opposite side of the first deflector from the first side.
14. The guardrail terminal of claim 10 , wherein energy dissipation of the guardrail terminal when positioned on the w-shaped guardrail supported by a plurality of posts having plastic moments in a range from about 9,000 ft-lb to about 38,000 ft.-lbs. is in a range of about 14 kilopounds (kips) to about 31 kips with an impact on the second end of the guardrail terminal at 15 degrees or less relative to the w-shaped guardrail.
15. The guardrail terminal of claim 10 , wherein the first deflector is configured to reshape the w-shaped guardrail from a configuration including three reversals of direction along a transverse length of the w-shaped guardrail to a shape having only a single reversal of direction.
16. A guardrail assembly, comprising:
a w-shaped guardrail;
a guardrail terminal configured to receive the w-shaped guardrail, the guardrail terminal including an impact face and a deflector extending horizontally from an interior wall of the guardrail terminal, the guardrail terminal and deflector configured to fold the w-shaped guardrail; and
a plurality of posts supporting the w-shaped guardrail,
the plurality of posts having plastic moments perpendicular to the w-shaped guardrail in a range from about 9,000 ft-lb to about 38,000 ft.-lbs.
17. The guardrail assembly of claim 16 , wherein the plastic moments are achieved with a head-on force of about 14 kilopounds (kips) to about 31 kips.
18. The guardrail assembly of claim 17 , wherein the plastic moments and the head-on force are at an impact angle of 15 degrees or less relative to the w-shaped guardrail.
19. The guardrail assembly of claim 16 , wherein the deflector folds the w-shaped guardrail such that a first end and a second end of the w-shaped guardrail in a transverse direction to a longitudinal extent of the w-shaped guardrail are repositioned from extending in a first direction to extending in a second direction that is opposite to the first direction.
20. The guardrail assembly of claim 16 , wherein the w-shaped guardrail initially includes three reversals of direction along a transverse direction of the w-shaped guardrail, and after the w-shaped guardrail is folded, the w-shaped guardrail includes only a single reversal of direction along the transverse direction of the w-shaped guardrail.