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Bolts in asymmetrical transition section

State IA
Description Text

When testing, does MwRSF use two bolts for the center post of the asymmetrical section or just one? I would default to assuming two or there wouldn’t be a need to have the bottom hole, but I’ve seen other states with just one in the top slot and I can’t find a definitive answer.


I’ve seen some drawings where there will be a nail near the bottom hole to prevent rotation with a wood blockout and wood post but since MwRSF typically tests with steel posts, that wouldn’t apply. However, I’m not sure if the nail would be needed as it would be a thrie-beam blockout and the weight distribution may keep the blockout from rotating anyway. Thoughts?

  • Approach Guardrail Transitions
Other Keywords none
Date July 12, 2016


All of the MASH testing of the the asymmetrical W-to-thrie beam transition piece was conducted with only the top post bolt installed. This was done  partially because standard thrie beam posts will not have a post bolt hole in the correct location for the lower slot in the rail, and to allow for the blockout in that location to rotate and reduce snag. Thus we would recommend using only the single bolt in that location.


We don’t have evidence that using both bolts is an issue, but we recommend using only the top bolt to be consistent with the full-scale crash tests.


Date July 13, 2016

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