Can an asymmetrical (thrie-beam to w-beam) section be used to connect the bullnose crash cushion, thrie-beam section to the 31” high MGS standard? Our standard currently uses a symmetrical section between post 10 and 11 (to go from thrie-beam to 28” high w-beam).
Assume that no curbing will be used. And in some cases the MGS portion will then connect to an AGT or to another bullnose.
If this can be done, then we also need guidance on post location from the Bullnose system to the MGS portion.
Attached are the current standards for the MnDOT Bullnose and the two types of thrie-beam to w-beam transitions.
Thank you.
Thank you for the response. We just have one more quick question regarding post type (wood to steel) change locations.
We are proposing to change from a wood post (# 10) to steel post (# 11).
Let us know if this post type change location is ok. (See Attached pdf figure).
I believe that you can start the use of CRT posts at post no. 9 if you wish. The NCHRP 350 bullnose testing with the UBSP posts used the standard steel posts starting at post no. 9.
Thus, I don’t see the use of steel posts at post no. 10 being an issue. We did use 78” long posts in the thrie beam sections rather than the 72” long posts used for the MGS and would recommend those posts in the thrie beam region. We would also recommend that the shorter blockouts used in the bullnose be used throughout the thrie beam region.
Thanks
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