Clay Pipe Engineering Manual

Chapter 5, Trench Load Tables

Loads on Vitrified Clay Pipe in Pounds Per Linear Foot Caused by Backfilling with Various Materials
. . . Based on Marston's Equations.

These tables show the loads imposed upon pipe by four common types of backfill soil. Loads are calculated using 100 lb./cu. ft. soil weight.

When the actual soil weight is known to vary from the estimated value, the tabulated loads may be adjusted up or down by direct ratio.

The tables list loads on pipe diameters 6-inch through 42-inch.

(See page 38 for discussion on embank-ment loads.)

Computerized Trench Load Design

The National Clay Pipe Institute has developed a computerized trench load design program based upon the Marston Equations and the pipe bedding classes described in ASTM C12 Standard Practice for Installing Vitrified Clay Pipe Lines.

The program accepts specific input data or common default values may be used if the data is not readily available. The program yields safety factors for combi-nations of trench depth and width, soil types and densities. Live loads and impact factors may also be included at trench depths less than 8 feet.

The trench load program is available from the National Clay Pipe Institute or its member manufacturers.

LOADS ON CLAY PIPE CAUSED BY BACKFILLING WITH VARIOUS MATERIALS

| 6" | 8" | 10" | 12" | 15" | 18" | 21" | 24" | 27" | 30" | 33" | 36" | 39" | 42" |

NCPI Engineering Manual

Request a copy of the Clay Pipe Installation Manual or other publications from NCPI