Foundations · Pad, strip & combined footings
Pad footing calculator
Square pad: bearing, flexural steel, one-way shear and punching shear.
Standard: AS 3600 Cl 8, 9.3
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 |
|---|---|---|
| Footing width B (square) | 2.4 | m |
| Depth D | 600 | mm |
| Column size | 400 | mm |
| Cover | 65 | mm |
| Bar diameter | 16 | mm |
| f'c | 32 | MPa |
| fsy | 500 | MPa |
| Service load | 1000 | kN |
| Factored load N* | 1350 | kN |
| Allowable bearing | 200 | kPa |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| B required for bearing | 2.32 | m |
| Service pressure | – | kPa |
| Factored net pressure | – | kPa |
| d | 519 | mm |
| M* at column face | – | kNm/m |
| Steel N16 @ | – | mm each way |
| One-way shear V* / φVuc | – / 277 | kN/m |
| Punching V* / φVuo | – / 2,569 | kN |
- ✗ Bearing q ≤ qa
- ✗ One-way shear
- ✗ Punching shear
Method, formulas and assumptions
- q = Ns/A + 25D = – kPa; qu = N*/A = – kPa (net)
- Cantilever a = (B − c)/2 = 1.00 m; M* = qu a²/2
- One-way shear at d from face: Vuc = 0.15 b dv √f'c (kv = 0.15, conservative)
- Punching: u = 4(c + d), fcv = 0.17(1 + 2/βh)√f'c ≤ 0.34√f'c, φ = 0.7
- V*punch = qu [A − (c + d)²]
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.