Temporary works & site · Cranes & lifting
Spreader beam (lifting) — CHS strut, AS 4100 calculator
A tubular spreader carrying a load from two lower slings with a two-leg upper sling to the hook. Sling geometry gives the upper-sling tension and the compression in the spreader; the CHS is checked for member compression to AS 4100 with the effective length equal to the lug spacing.
Standard: AS 4100 Cl 6 member compression (αb = −0.5, cold-formed CHS) · AS 4991 lifting devices: dynamic factor · sling geometry
Open the live calculator → All temporary works & site calculators
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 |
|---|---|---|
| Load (incl. lower rigging) | 24 | t |
| Spreader length (lug centres) | 6 | m |
| Upper sling vertical height | 3 | m |
| Dynamic factor | 1.3 | |
| Section | 219.1 × 6.4 CHS | |
| Yield stress | 350 | MPa |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Design hook load W·dyn | 306 | kN |
| Upper sling angle to horizontal | 45.0 | ° |
| Upper sling leg tension | 216 | kN |
| Spreader compression N* | 153 | kN |
| Slenderness Le/r | 80 | |
| αc | 0.642 | |
| φNc | 865 | kN |
- ✓ N* ≤ φNc — 18 %
- ✓ Upper sling angle ≥ 45° to horizontal — 45.0°
- ✓ Le/r ≤ 200 — 80
Method, formulas and assumptions
- Two-leg upper sling at angle θ = atan(h/(L/2)): leg tension = P/(2 sin θ), spreader compression = P/(2 tan θ). Lower slings vertical.
- AS 4100 Cl 6.3.3 with kf = 1, αb = −0.5 (cold-formed CHS), Le = lug spacing. Check lugs, welds and shackles separately; proof-load and certify lifting gear to AS 4991.
Related temporary works & site calculators
- Crawler crane lift check (radius, capacity, ground bearing) — Checks a crawler-crane lift against a load chart (radius vs rated capacity, interpolated), adds hook block…
- Mobile crane outrigger pad / crane mat — Worst outrigger load for a mobile crane slewing over a corner (crane + load share plus the load moment over…
- Lifting lug (padeye) plate check — A plate padeye with a pin hole: bearing on the plate, net-section tension across the hole, shear tear-out to…
- Precast pile lifting & pitching moments — A square precast concrete pile lifted horizontally at two points (0.207L from each end, equal hogging and…
- Driven pile: Hiley formula (set, capacity, blows per 250 mm) — Relates the final set per blow to the pile resistance for a drop or hydraulic hammer: R = ηh·W·h·ηb/(s +…
- Bored pile: concrete volume, cage and pour — Concrete and reinforcement quantities for a bored pile: theoretical and overbreak volume, trucks, tremie…
For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.