MASH 31″ Guardrail Post

NU-GUARD-31 is a strong post guardrail system available for use without offset blocks for 31″ rail height applications. The system is crash-test proven to guard against collisions with fixed objects or hazards.

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  • Crashworthy to NCHRP 350 and MASH criteria.
  • Does not require offset blocks.
  • FHWA accepted for use on roads with design speeds up to 65 mph. (Ref. B-162)
  • RIB-BAK 5 lb./ft. U-Channel post is easier and faster to install than wood or I-beam posts.
  • RIB-BAK U-Channel posts available galvanized or powder coated.
  • Approved for both roadside and median applications.
  • Median configurations for 31″ rail height applications.
  • The narrow profile of this barrier is valuable when roadside space is limited.
  • Through-bolt slot works to maintain rail height during impact.


  • Guardrail: Use with standard w-beam (AASHTO M-180, Class A or B, Type II)
  • W-Beam Height: 31” for Roadside and Median
  • RIB-BAK U-Channel: 5 lb./ft.; 6’ 6”; Nucor Grade SP-80
  • Post Spacing: 6’ 3” Typical
  • Offset Blocks: Not Required
  • Slope: 6 to 1 or less
  • NCHRP 350 Tested: TL-3 and TL-4 Compliant
  • MASH Tested: MASH TL-3 Compliant

Product Diagram

Product Images

Product Documents

PI Sheet



NU-GUARD™-31 Installation Manual