Static-analysis capacity of a single pile through up to three soil layers: skin friction plus end bearing, nominal and factored, with a capacity-vs-depth curve. Driven piles use the API α-method in clay and the Meyerhof SPT method in sand; bored piles (drilled shafts) use the AASHTO α-method in clay and the O’Neill–Reese β-method in sand.
The pile tip may sit inside any layer; layers below the tip only matter if you deepen the pile. Bored piles ignore shaft friction in the top 1.5 m and the bottom one diameter in clay (GEC-10).
Defaults follow AASHTO Table 10.5.5.2.3-1 / 10.5.5.2.4-1: driven static analysis φ ≈ 0.35; bored shafts φside ≈ 0.45–0.55, φtip ≈ 0.40–0.50 depending on soil and method. Adjust to your jurisdiction.
| Segment | Method | fs avg (kPa) | R (kN) |
|---|
Static-analysis capacity is a preliminary number, not a design guarantee — on real jobs it gets confirmed or replaced by load tests, PDA/CAPWAP on driven piles, or Osterberg cells on large bored shafts, and the resistance factor rises with the quality of that verification (that is the whole logic of AASHTO Table 10.5.5.2.3-1). A few habits worth keeping: the Meyerhof SPT numbers here assume displacement piles — halve the shaft friction for H-piles; the O’Neill–Reese β already bakes depth into the coefficient, so resist the urge to also cap σ′v; and in the Gulf the layer that matters is usually the weak calcareous siltstone/mudstone below the sand — treat it as a cohesive material with a lab-derived Su rather than pushing the sand correlations past their range. Group effects, downdrag, uplift and lateral response are separate checks this tool deliberately leaves out.