Ice Loading
When ice thickness > 0, TowerPlot applies radial ice to all structural members and appurtenances per TIA-222-H Section 2.6.10.
Parameters
| Parameter | Description | Default |
|---|---|---|
| Radial Ice Thickness | Uniform ice applied to all members | 0 mm (no ice) |
| Ice Density | Standard per TIA-222-H | 900 kg/m³ |
Effects of Ice
Ice loading has two compounding effects:
1. Increased EPA
Ice increases the effective diameter of every member:
Diameter(iced) = Diameter(bare) + 2 × ice thickness
This increases the projected area and therefore the wind force on every section.
2. Increased Dead Load
The ice adds weight to every member:
Ice weight = π × [(D/2 + t)² - (D/2)²] × L × ρice
Where D = member diameter, t = ice thickness, L = member length, ρice = 900 kg/m³.
Ice + Wind Combinations
When ice is specified, TowerPlot generates additional load combinations:
| Combination | Formula | Purpose |
|---|---|---|
| Ultimate Ice + Wind | 1.2D + 1.0Di + 1.0Wi | Strength under combined loading |
| Uplift Ice + Wind | 0.9D + 1.0Di + 1.0Wi | Uplift check under ice + wind |
Wi = Wind-on-ice speed (reduced from the bare wind speed per TIA-222-H). Di = Ice dead load — weight of radial ice on all members.
Under TIA-222-F (ASD), the ice + wind combination is unfactored: D + 0.75Wi + I.
Ice loading often governs the design of towers in northern climates. Even 12mm of radial ice can increase wind loads by 20–40% due to the increased member diameters.