Concrete · Materials & serviceability
Design shrinkage strain calculator
Autogenous plus drying shrinkage at time t with the hypothetical thickness, environment factor and basic drying strain by location.
Standard: AS 3600 Cl 3.1.7
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 |
|---|---|---|
| f′c | N32 | MPa |
| Time after start of drying | 10000 | days |
| Section area | 300000 | mm² |
| Exposed perimeter | 1600 | mm |
| Environment k4 | Interior | |
| Basic drying strain ε*csd.b | 800 (Sydney, Brisbane) | µε |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Hypothetical thickness 2Ag/ue | 375.0 | mm |
| Autogenous ε = (0.06 f′c − 1)·50 µε (final) | 46.00 | µε |
| α1 = 0.8 + 1.2 e^(−0.005 th) | 0.984 | |
| k1 = α1 t^0.8/(t^0.8 + 0.15 th) | 0.950 | |
| εcsd.b = (1 − 0.008 f′c) ε*csd.b | 595.2 | µε |
| Drying εcsd = k1 k4 εcsd.b | 367.7 | µε |
| Total design shrinkage strain | 413.7 | µε |
- ✓ Total shrinkage below 1000 µε
Method, formulas and assumptions
- Hypothetical thickness 2Ag/ue = 2*3.000e+5/1600 = 375 mm
- Autogenous ε = (0.06 f′c − 1)·50 µε (final) = (0.06*32-1)*50*(1-EXP(-0.1*10000)) = 46 µε
- α1 = 0.8 + 1.2 e^(−0.005 th) = 0.8+1.2*EXP(-0.005*375) = 0.98403
- k1 = α1 t^0.8/(t^0.8 + 0.15 th) = 0.98403*10000^0.8/(10000^0.8+0.15*375) = 0.9503
- εcsd.b = (1 − 0.008 f′c) ε*csd.b = (1-0.008*32)*800 = 595.2 µε
- Drying εcsd = k1 k4 εcsd.b = 0.9503*0.65*595.2 = 367.65 µε
- Total design shrinkage strain = 46+367.65 = 413.65 µε
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.