Foundations · Laterally loaded piles
Laterally loaded pile (Broms) calculator
Ultimate lateral resistance of a free-head pile in sand or clay, short (rigid) or long (yielding) mode.
Standard: Broms (1964) free-head short/long piles
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 |
|---|---|---|
| Soil | Cohesive (cu) | |
| Pile diameter D | 0.6 | m |
| Embedded length L | 10 | m |
| Load eccentricity e above ground | 0.5 | m |
| cu (clay) | 50 | kPa |
| γ (sand) | 18 | kN/m³ |
| φ′ (sand) | 32 | ° |
| Pile yield moment My | 400 | kNm |
| Factor of safety on Hu | 2.5 | |
| Applied lateral load | 60 | kN |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Short-pile Hu | 832 | kN |
| Long-pile Hu (My = 400) | 221 | kN |
| Governing mode | long (yields) | |
| Ultimate Hu | 221 | kN |
| Allowable Hu/FS | 88 | kN |
| Max moment if short | 2,446 | kNm |
- ✓ Applied load ≤ Hu/FS
Method, formulas and assumptions
- Soil reaction 9cu·D below 1.5D (Broms)
- Short: Hu(e + 1.5D + 0.5f) = 2.25·D·cu·g², f = Hu/(9cuD), L = 1.5D + f + g
- Long: Hu(e + 1.5D + 0.5f) = My
- Hu = lower governing value
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.