Corrugated Metal Pipe Strength

Corrugated metal pipe (CMP) is structurally designed in accordance with AASHTO Section 12. Fill height tables are presented in the
Conduit Strength and Durability
document. These fill height tables are based on the following minimum parameters:
  • AASHTO Section 12 Design Guide - Service Load Design
  • soil unit mass of 120 lb./cu.ft. (1,922 kilograms per m
    3
    )
  • 90% standard density proctor AASHTO T99
  • minimum internal factor of safety: wall area = 2.0, buckling = 2.0, and seam strength = 3.0.
  • maximum height for pipe arch limited to 39,146 lb./sq.ft. (191,531 kilograms per m
    2
    ) of corner bearing pressure
  • HS 20 and HS 25 live loading
For structures not represented by tables and conditions outside of above referenced conditions, contact the Bridge Division, Structures Section.