Trench Pipe Bedding and Backfill Take-Off
Bedding stone (cy and tons), pipe-zone embedment aggregate.
Example
You enter
- Trench width (ft) 2
- Pipe outside diameter (in) 12
- Bedding depth below pipe (in) 4
- Cover above pipe (ft) 3
- Run length (ft) 100
- Stone density (tons/cy) 1.4
You get
- Bedding stone 2.469
- Embedment (pipe-zone) aggregate 4.50 cy
- Backfill above pipe 22.2 cy
Checked against published worked examples from: ASTM D2321 / municipal bedding detail.
Details, formula, and sources
ScopeBedding stone (cy and tons), pipe-zone embedment aggregate, and backfill volume for a pipe trench from the trench and pipe dimensions per ASTM D2321.
Formula or tablebedding_cy = width x (bedding/12) x length / 27; bedding_tons = bedding_cy x density; embed_area = width x od_ft - (pi/4) od_ft^2; embedment_cy = embed_area x length / 27; backfill_cy = width x cover x length / 27.
Source and editionASTM D2321 (installation of buried thermoplastic pipe) and the typical municipal bedding detail by name; first-principles take-off.
Free accessASTM D2321 is a published consensus standard. The take-off geometry is public.
What governsEstimate. AHJ and licensed professional govern.
API field namestrench_width_ft, pipe_od_in, bedding_depth_in, cover_ft, length_ft, stone_density_tcy, bedding_cy, embedment_cy, backfill_cy
- Stone density 1.4 tons per loose cy (default; supplier ticket governs)aggregate supplier data
- Pipe-zone subtraction embedment excludes (pi/4) x OD^2 (the pipe's cross-section)first-principles