Can you tell me if the MoDOT thrie beam guardrail on BRIDGE using a W6x20 post at 6’-3” spa. with or without W6x15 steel blockout is acceptable for MASH TL-3?
I believe our current system is NCHRP 350 TL-3 compliant which can be utilized with or without a steel blockout.
Gregory Sanders, P.E.
Structural Development and Support Engineer
Missouri Dept. of Transportation
I believe that the bridge railing system was crash tested under the NCHRP Report No. 230 criteria. Unfortunately, I am unaware of any crash testing under NCHRP Report No. 350 on this exact bridge railing. There may have been a grandfather from 230 to 350** on this bridge railing.
**Memorandum on Crash Testing of Bridge Railings, May 30, 1997, File Designation HNG· 14, Federal Highway Administration (FHWA), Washington. D.C ., 1997.
MASH testing would be recommended for the bridge railing.
The approach guardrail transition (AGT) was largely crash tested under NCHRP 350 and MASH using the Test Level 3 safety performance criteria. The various transition testing programs on similar systems are attached below.
Successful 350 Testing on Similar AGT
https://mwrsf.unl.edu/researchhub/files/Report87/TRP-03-71-01.pdf
Failed 2000P & Passed 820C – Original AGT & Transition Element
https://mwrsf.unl.edu/researchhub/files/Report188/TRP-03-94-00.pdf
Failed 2000P & Failed 2000P – Modified AGT w/ Rubrail
https://mwrsf.unl.edu/researchhub/files/Report186/TRP-03-91-99.pdf
New Transition Element R&D
https://mwrsf.unl.edu/researchhub/files/Report108/TRP-03-167-07.pdf
New Transition Element and Standardized AGT – MASH Testing
https://mwrsf.unl.edu/researchhub/files/Report38/TRP-03-210-10.pdf
New Standardized AGT w/ Curb – MASH Testing
https://mwrsf.unl.edu/researchhub/files/Report295/TRP-03-291-14.pdf
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