Foundations · Pile capacity
Rock-socketed pile calculator
Socket shaft resistance from rock UCS, base resistance as a multiple of qu, geotechnical reduction factor φg.
Standard: Rowe & Armitage (1987) fs = 0.45√qu · Pells base
Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Socket diameter | 900 | mm |
| Socket length | 3 | m |
| Rock UCS | 10 | MPa |
| Shaft coefficient (0.45 rough / 0.6 R4) | 0.45 | |
| Base factor | 2.5 | |
| φg (AS 2159) | 0.55 | |
| Design axial load | 9000 | kN |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| fs = αf √qu | 1,423 | kPa |
| Shaft πDL fs | 12,071 | kN |
| Base Nb qu Ab | 15,904 | kN |
| Design φg(Rs + Rb) | 15,386 | kN |
- ✓ N* ≤ Rd,g
Method, formulas and assumptions
- fs = αf √qu = 0.45*SQRT(10)*1000 = 1423 kPa
- Shaft πDL fs = PI()*900/1000*3*1423 = 12071 kN
- Base Nb qu Ab = 2.5*10*1000*PI()*(900/1000)^2/4 = 15904 kN
- Design φg(Rs + Rb) = 0.55*(12071+15904) = 15386 kN
Related foundations calculators
- Pile axial capacity (layers, AS 2159 φg) — Shaft and base resistance through layered sand (SPT N) and clay (su), with the AS 2159 geotechnical…
- Negative skin friction (downdrag) — Drag load on a pile from a settling layer (fill over soft clay) by the β method, and the maximum axial force…
- Rock-socketed pile: capacity and settlement (Rowe & Armitage) — Bored pile socketed into rock below a soil overburden. Socket side resistance f = k√qu (Rowe & Armitage: k =…
- Pile capacity and settlement from CPT (LCPC method) — Pile designed directly from a cone penetration test, as in the GEO5 Pile CPT program. The equivalent base…
- Neutral plane, drag force and downdrag settlement (unified method) — Single pile through settling ground. The load curve (dead load plus accumulated negative friction from the…
- Helical (screw) pile capacity — Compression capacity as the sum of helix bearing (c Nc + q′ Nq) plus torque-correlated capacity for…
- Micropile (grout–ground bond + structure) — Bond length capacity and the structural capacity of grout plus bar (ASD 0.4f′c, 0.47fy).
- Driven pile capacity from SPT (Meyerhof) — Shaft friction layer by layer from SPT N and base resistance from N at the toe with the embedment into the…
For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.