BE-02 Open Cut Method: Embedment Zone

Minimum Trench Width Calculation in the US for Various Pipe Materials

How to Calculate the Minimum Trench Width for Centrifugally Cast Fiberglass-Reinforced Polymer Mortar Pipes?

The table below presents the minimum trench width as a function of pipe outside diameter for centrifugally cast glass-fiber reinforced polymer mortar (CCFRPM) pipe installation using the open cut method.


Minimum trench width for centrifugally cast, glass-fiber-reinforced, polymer mortar (CCFRPM) pipe as per [HOBAS CCFRPM Guide]

Minimum Trench Width Calculation Formula Based on Pipe Outside Diameter (OD)
Pipe OD (in) Minimum Distance on Each Side of the Pipe (in)
SPT* ≤ 8 SPT* ≥ 8
18 to 20 6 4
24 to 33 9 6
36 to 48 12 8
51 to 72 18 12
78 to 126 24 16
*SPT = Standard penetration test blows/ft. as per [ASTM D1586]



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