Wind loading
Based on AS1170.2 2011

Region Region A1 Region A2 Region A3 Region A4 Region A5 Region A6 Region A7 Region B Region C Region D Region W

Recurrance interval, R 5 years 10 years 20 years 25 years 50 years 100 years 200 years 250 years 500 years 1000 years 2000 years 2500 years 5000 years 10000 years

Aerodynamic shape factor, C_fig

Dynamic response factor factor, C_dyn

Terrain height multiplier, M_z,cat

Sheilding multiplier, M_s

Topographic multiplier, M_t

Density of air, ρ_air kg/m³

Regional wind speed, V_R m/s

Design wind pressure, p kPa (for M_d=1.0)

M_d - Wind direction multiplier

V_sit,β - Wind site speed

p - Design wind pressure

North direction °

Structure X dim m

Structure Y dim m

Terrain height multiplier, M_z,cat

Height, z m

Terrain category 1 Terrain category 1.5 Terrain category 2 Terrain category 2.5 Terrain category 3 Terrain category 4

Avg roof height of shielding bldgs, h_s m

Avg breadth of shielding bldgs, b_s m

Avg roof height of structure, h m

(20h = m)

Shielding bldgs within 45° and 20h, n_s

Shielding multiplier, M_s

Hill or ridge Escarpment (upwind) Escarpment (downwind)

Height of hill/ridge/escarpment, H m

Distance from crest to half height, Lu m

Distance from structure to crest, x m

Height, z m

Length scale, L₁ m

Length scale, L₂ m

Topographic multiplier, M_t