Engineering Tools
Crane Wind Load Calculator
Wind force on suspended loads and crane structures per AS 5222:2021. In-service operating wind (§5) and out-of-service storm wind with height-varying profile (§6). Runs entirely in your browser.
Wind speed
Design pressure, not operational limit. The presets are AS 5222 structural-sizing values. Operational shutdown wind comes from the OEM duty manual — typically around 9–14 m/s for mobile cranes, lower for booms with large sail loads.
Reference: AS 5222 design pressure classes
The standard tabulates three design classes for structural sizing — secured / light-wind, normal outdoor, and process / continuous-duty — at 14, 20, and 28.5 m/s respectively. Use the standard's own table when specifying a structural design pressure; for operational lift planning, enter the forecast wind speed above (BoM forecast or site anemometer).
Suspended load
Results
F_w = c_H × A_H × p (AS 5222 eq 3)
Coefficient guide — typical ranges
Editorial ranges drawn from common wind-engineering literature (Eurocode EN 1991‑1‑4, Cook's Designer's Guide to Wind Loading, Hoerner's Fluid‑Dynamic Drag, ESDU data sheets, ISO 4354). Values are first-pass guidance only — for authoritative design figures consult AS 5222 §5.4 Table 2 (shape coefficients) and Table 4 (shielding factors).
Shape coefficient C_f
C_f is the drag coefficient referred to the projected solid area. It depends on member shape, aspect ratio, surface roughness, and (for round sections) the Reynolds number Re = v·d/ν.
| Member type | Typical C_f | Notes |
|---|---|---|
| Flat plate / sheet panel | 1.1 – 2.0 | Square panel ≈ 1.1; rises with aspect ratio l/b — long, slender plates approach 2.0. |
| Suspended load — flat / billboard | 1.2 – 2.0 | Treat as flat plate at the worst-case orientation. Tarpaulins, signage, façade panels. |
| Suspended load — compact / rounded | 0.7 – 1.1 | Steel coils, tanks, generators, motors — closed bodies with rounded faces. |
| Box / I / channel section | 1.4 – 2.0 | Sharp-edged structural sections. Higher with low slenderness; lower for long booms. |
| Circular section — subcritical | ≈ 1.2 | Re < ~2×10⁵ (small diameter or low wind). Rough surface keeps you here longer. |
| Circular section — supercritical | 0.5 – 0.8 | Re > ~4×10⁵ — drag crisis. Smooth large-diameter pipes, mast columns at storm speeds. |
| Lattice frame — sharp-edge members | 1.4 – 1.8 | Referred to solid area. Solidity ratio φ = solid / enclosed; lower φ → upper end of range. |
| Lattice frame — round-tube (supercritical) | 0.8 – 1.2 | Tubular booms in storm wind. Drops markedly once individual members go supercritical. |
| Machinery house / cab (enclosed) | 1.1 – 1.4 | Treat as small bluff building. Apply to projected face area. |
Reynolds number rule of thumb: Re ≈ 70 000 × v(m/s) × d(m) for air at 20 °C. A 0.3 m diameter circular boom in 30 m/s wind gives Re ≈ 6.3×10⁵ — supercritical.
Shielding factor η
η is the fraction of the upstream wind that reaches the next downstream frame in a series of identical, equally spaced parallel frames (e.g. lattice booms, scaffold towers, shutter slats). η = 0 means full shielding; η = 1 means no shielding.
Two parameters drive it: solidity ratio φ (the frame's solid silhouette area / enclosed area) and spacing ratio a/b (gap between facing sides / breadth of member across the wind).
- High solidity (φ > 0.5) + close spacing (a/b < 1) → strong shielding, η typically 0.1–0.3
- Mid solidity (φ ≈ 0.2–0.4) + moderate spacing (a/b 1–4) → η typically 0.4–0.7
- Low solidity (φ < 0.1) or wide spacing (a/b > 4) → little shielding, η > 0.8
AS 5222 §5.5 caps the shielding accumulation at 8 frames — every additional downstream frame past the 8th contributes the same incremental load as the 8th (implemented in this calculator).
v_ref for out-of-service wind (Australia)
v_ref is the 50-year 10-minute mean storm wind speed at 10 m above flat open country. AS 1418.1 maps Australia into wind regions and tabulates v_ref by region — typical values fall in roughly 30–55 m/s, increasing toward the cyclone-prone north. Cross-reference your project's wind-region classification (usually from the structural engineer or AS/NZS 1170.2) before entering a value.