Concrete · Precast & tilt-up
Tilt-up panel: lifting and in-service design calculator
Tilt-up wall panel. Lifting: the panel is raised from the casting bed on two or four rows of inserts; the peak bending moment per metre (inserts at the optimum positions) with a suction/impact factor gives the flexural tensile stress, compared with the early-age flexural strength 0.6√f′cp with a safety factor. In service: the panel spans between the floor slab and the roof under wind and an eccentric roof load; the moment is magnified for slenderness and checked against the capacity of the central mesh.
Standard: AS 3850.2 tilt-up (lifting from horizontal, suction/impact factor) · AS 3600 Cl 3.1.1.3 flexural tensile strength · AS 3600 Cl 11 / Cl 10.4 slender panel with moment magnification
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 |
|---|---|---|
| Panel height (lifted length) | 9 | m |
| Panel width | 4 | m |
| Thickness | 175 | mm |
| Density | 24.5 | kN/m³ |
| Lifting arrangement | Two rows of inserts (0.207H from ends) | |
| Suction / impact factor | 1.2 | |
| Concrete strength at lift | 20 | MPa |
| Safety factor on cracking | 1.5 | |
| In-service span (slab to roof) | 8.5 | m |
| Design wind pressure (ULS) | 1.2 | kPa |
| Design roof load per metre N* | 15 | kN/m |
| Roof load eccentricity | 60 | mm |
| f′c (28 day) | 32 | MPa |
| Ec | 30100 | MPa |
| Mesh area (central layer) | 303 | mm²/m |
| fsy | 500 | MPa |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Panel self-weight | 4.29 | kPa |
| Lifting moment per metre (0.0214wH² × 1.2) | 8.92 | kNm/m |
| Lifting flexural stress | 1.75 | MPa |
| Early flexural strength 0.6√f′cp / SF | 2.68 / 1.79 | MPa |
| Slenderness span / t | 49 | |
| Buckling load Nc (EI = 0.4EcIg) | 735 | kN/m |
| Moment magnifier δ | 1.021 | |
| First-order M* (wind + eccentricity) | 11.29 | kNm/m |
| Magnified M* | 11.52 | kNm/m |
| Capacity φMu (central mesh + N*) | 11.92 | kNm/m |
- ✓ Lifting stress ≤ f′ct.f/SF (uncracked lift) — 98 %
- ✓ In-service M*·δ ≤ φMu — 97 %
- ✓ Span/thickness ≤ 50 — 49
Method, formulas and assumptions
- Lifting: two rows at 0.207H from each end give equal hogging and sagging M = 0.0214wH² per metre; four rows with equalising rigging about 0.0054wH². Multiply by the suction/impact factor (1.2–1.5).
- Cracking check against f′ct.f = 0.6√f′cp at the lift age with a safety factor (AS 3850.2 requires the panel not to crack during lifting).
- In service: simply supported between slab and roof, M* = wH²/8 + N*e/2, δ = 1/(1 − N*/Nc), Nc = π²(0.4EcIg)/H²; capacity of the central mesh with the axial load, φ = 0.85.
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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.