Patent ID: 9139968
Filing Date: 2015-09-22
Classification: E01F,Y10T

Abstract:
1. A guardrail which includes a plurality of terminal end rails which longitudinally extend between a plurality of support posts wherein a first four rails of the plurality of rails, situated at a terminal end of a guardrail connected to an impact head, are telescopically connected to one another at respective downstream and upstream ends thereof, the guardrail comprising: an impact slider joined to a downstream portion of a terminal rail, the impact slider surrounding the downstream portion of the terminal rail and an upstream portion of an adjacent second rail and being laterally supported by a first support post; a first set of frangible shear bolts which are the sole bolts connecting a downstream portion of the second rail and an upstream portion of an adjacent third rail together, the second and third rails being laterally supported by a second support post without being bolted thereto; and a second set of frangible shear bolts which connect a downstream portion of the third rail and an upstream portion of an adjacent fourth rail together, wherein at least one standard post bolt connects the third and fourth rails to a third support post, wherein said standard post bolt increases the relative strength of the connection of the third and fourth rails compared to the connection of the second and third rails; wherein when the impact head is impacted by a vehicle, the impact slider allows the terminal rail and second rail to telescope relative to each other, and subsequently the first set of frangible shear bolts fail before the second set of frangible shear bolts such that the second and third rails telescope relative to one another prior to telescoping of the third and fourth rails.