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Barrier Flare Rates

State WI
Description Text

I have a project where project staff may have to flare beam guard at a greater rate than what is listed in table 5.7 of the RDG.  What research was used to develop this table?   Does MwRSF have any guidance on this topic?


Just yesterday, I was asked about flare rates for concrete barrier.  Does MwRSF have some research on this topic?

  • Guardrail
Other Keywords none
Date May 6, 2010


I am attaching a pdf copy of a MwRSF research report regarding flare rates. As noted in the MwRSF Report No. 157, the guardrail flare rates were determined by James Hatton, FHWA. Unfortunately, I do not believe that these flare rates were based on actual full-scale vehicle crash testing.


Later, MwRSF conducted a flare rate study involving the MGS which shown that flare rates as steep as 5:1 were acceptable. I have provided a link to download this report if you cannot find it. Of course, our guidance in this report pertains only to the MGS.


The file 'TRP-03-191-08.pdf' (86.7 MB) is available for download at

for the next 7 days.

It will be removed after Wednesday, May 26, 2010.


Finally, I have included a pdf copy of a journal paper covering the flare rate topic that may also provide more refined conclusions and guidance. In Section 8 of the paper and based on computer simulations, the authors note that the modified G41s may not perform effectively when installed with flare rates steeper than 15:1 under TL-3 impacts under NCHRP Report 350.


Years ago and while at TTI, Dean prepared guidelines for temporary concrete barrier. I believe those guidelines are published in NCHRP Report 358.


Date May 19, 2010
Attachment TRP-03-157-04.pdf
Attachment Flare-Rates--IJoIE-2009.pdf

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