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MGS without Blockouts

Question
State WY
Description Text

I was looking through our stuff and I didn't see any reports about the MGS without blockouts and I didn't see any status for it in the quarterly report.  I am pretty sure that testing was already done.  Has a draft report (or final) been done?  Also, do you know if it was tested on flat ground, or was there a 1V:2H slope break directly behind it?

Keywords
  • Guardrail
Other Keywords none
Date March 1, 2012


Response
Response

That testing is completed and in the report stage. The system passed both the 1100C and 2270P testing on flat ground.

 

More thoughts on the non-blocked MGS.

The MGS for 2:1 fill slopes was crash tested and successfully evaluated under MASH when installed with a 12" deep wood blockout and with the rail positioned at 31". However, the system was not successful when tested at 27¾". As such, we do not know the lower bound for this system variation when used with a blockout.

As you know, the standard blocked MGS has a lower bound at 27¾" based on the successful MASH testing of the modified G4(1s).

MwRSF previously tested a non-blocked MGS under MASH when placed on wire-faced MSE walls with 6-ft long steel posts at the SBP of a 3:1 fill slope.

Based on the testing noted above combined with engineering judgment and the best available information, we believe that a non-blocked version (with backup plates) of the MGS for 2:1 fill slopes could likely meet the MASH impact safety standards when installed at the 31" mounting height. However, it should be noted that no crash tests have been performed on this exact variation and that the lower bound would likely be affected, as was the case for the blocked version on 2:1 slopes.

As a result and if deployed, it would be highly suggested that the system only be installed with a 31" minimum mounting height when used in a non-blocked version on 2:1 fill slopes using the longer posts. Of course, the proven crashworthy system which utilizes the blockout would provide the safest alternative.

Thanks

 

Date March 5, 2012


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