Corrugated Metal Pipe and Structural Plate

Determine the service life of corrugated metal structure by calculating the service life of the exterior and interior of the pipe using the site characteristics for the soil and water discussed in the previous section. The overall service life will be the lesser of the interior service life or exterior service life. The service life of a corrugated metal conduit is expressed by the sum of the base metallic coating, post applied coating, and paving or lining service life, as in Equation 14-1 and Equation 14-2:
EquationObject334401
Equation 14-1.
EquationObject335402
Equation 14-2.
where:
  • SL
    INT
    = service life of the interior of the pipe
  • SL
    EXT
    = service life of the exterior of the pipe
  • SL
    BMCI
    = service life of the base metallic coating interior
  • SL
    BMCE
    = service life of the base metallic coating exterior
  • SL
    PACI
    = service life of the post applied coating interior
  • SL
    PACE
    = service life of the post applied coating exterior
  • SL
    LI
    = service life of the paving or lining interior