Subgrade Underdrain Materials
Per-foot factors and totals for 6" wrapped underdrains (pipe, fabric, pea stone).
Width fixed at 1.5 ft; pipe fixed at 6 in; select depth and length to calculate.
Inputs
Fixed values: 1.5 ft width, 6-inch pipe, 1.5 ft fabric overlap, 1 ft seam allowance, and 100 lb/cu ft pea stone. Depth is selectable above.
Per-foot factors
Totals
Assumptions
- Fabric wrap width = trench width + (2 × depth) + overlap + seam allowance; overlap is fixed at 1.5 ft with a 1 ft seam.
- Peastone volume = (trench width × depth − pipe area) × run length; trench width is 1.5 ft and pipe diameter is 6 in.
- Outputs round to two decimals (MDOT convention) for LFT, SYD, and tons.