Vehicle crash attenuator apparatus
Crash attenuator guardrail apparatus includes an impact head and a backstop having a cable and guardrails supported by guardrail supports located between the impact head and the backstop. Frictional forces are applied to the cable to control and resist movement of the impact head toward the backstop and provide lateral resistance. The guardrail supports include a base having break away structure and brace members having bends and which shorten or lengthen to absorb energy resulting from vehicle impact.
1. A crash attenuator apparatus including a guardrail support extending upwardly from the ground, said guardrail support including a guardrail support base, a guardrail support post extending upwardly from said guardrail support base and a guardrail support brace structure bracing said guardrail support post to resist and control sideways tilting movement of said guardrail support post caused by vehicular impact on the crash attenuator apparatus from the side, said guardrail support post supporting two spaced, substantially parallel guardrails located on opposite sides of said guardrail support post and extending to adjacent guardrail support posts, said guardrail support brace structure including two double-ended brace members located at opposed sides of said guardrail support post and extending laterally relative to said guardrails, each double-ended brace member being of deformable, single piece, unitary construction and secured at the ends thereof to the guardrail support base and to the guardrail support post at a location thereon spaced from the guardrail support base, said guardrail support base extending laterally relative to said guardrails and said double-ended brace members attached to said guardrail support base at locations on said guardrail support base spaced from said guardrail support post and disposed on opposite sides of said guardrail support post and attached to said guardrail support post at locations on opposite sides of said guardrail support post below the guardrails supported by the guardrail support post, each said double-ended brace member having bends formed therein between said guardrail support post and said guardrail support base which deform enabling the overall length of said double-ended brace member between the ends thereof to shorten in response to opposed compressive forces being exerted at the ends thereof and the overall length of said double-ended brace member between the ends thereof to increase in response to opposed tensional forces being exerted at the ends thereof, the overall length of one of said double-ended brace members shortening due to deformation at the bends thereof and the overall length of the other of said double-ended brace members simultaneously increasing due to deformation at the bends thereof when a guardrail supported by said guardrail support post is struck by a vehicle from the side whereby both of said double-ended brace members will simultaneously absorb impact energy and control sideways tilting of said guardrail support post, deformation of said double-ended brace members and controlled sideways tilting of said guardrail support post under load caused by a guardrail supported by said guardrail support post being struck from the side by a vehicle moving said guardrail support post in the direction of the non-impacted guardrail supported thereby to tension the non-impacted guardrail and provide a reactive force to redirect the impacting vehicle, and said guardrail support post being fixedly attached to a portion of said guardrail support base frangibly connected to the rest of said guardrail support base and responsive to longitudinal forces being applied to said crash attenuator caused by endwise vehicular impact thereon to cause knockdown of said portion and the guardrail support post attached thereto in a longitudinal direction upon breaking of the frangible connection.
2. The crash attenuator apparatus according to claim 1 wherein said guardrail support base has opposed guardrail support base end portions, the guardrail support base being securely attached to the ground by mechanical fasteners at said guardrail support base end portions, and the remainder of the guardrail support base between said end portions comprising the portion of said guardrail support base fixedly attached to said guardrail support post and not being securely attached to the ground by mechanical fasteners, said support base end portions being frangibly connected to the remainder of said guardrail support base whereby said support base end portions will remain attached to the ground by said mechanical fasteners even after said guardrail support post and the remainder of said guardrail support base between said support base end portions are knocked down as a result of vehicular impact.
3. The crash attenuator apparatus according to claim 2 wherein lines of weakness are formed in said guardrail support base between the support base end portions and the remainder of the guardrail support base and provide the frangible connection therebetween.
4. The crash attenuator apparatus according to claim 3 wherein the width of the guardrail support base is lessened at the locations of the lines of weakness by notches at ends of the lines of weakness.