Design wind pressure PZ = 2.56×10−6 V²KZGCD converted exactly to SI, with the exposure-category KZ profile, drag coefficients for superstructure and substructure, the 1.46 kN/m wind-on-live-load line, and the Strength III vertical wind pressure.
B = urban/suburban terrain, C = open country (default for most bridge sites), D = flat coastal exposure facing open water — the usual pick for sea crossings and corniche viaducts.
Girder + deck edge + barrier/parapet, the full solid strip the wind sees.
| Substructure pressure (CD = 1.6) | – |
| Substructure force | – |
| Wind on live load WL (at 1.8 m above deck) | 1.46 kN/m |
| WL on this span | – |
| Vertical wind 0.96 kPa (Strength III) | – |
The 9th-edition rewrite replaced the old base-pressure tables with this ASCE-style gust formula, and the practical consequence is that height and exposure now matter as much as the wind map: the same girder at Z = 60 m in exposure D sees roughly double the pressure it does at 10 m in exposure C. Use the mid-height of the exposed strip for Z, not the deck level. The 185/129/113 km/h presets are the generic 115/80/70 mph values — Gulf projects typically specify 3-s gusts around 160–190 km/h, but always take V from the project design criteria, not a default. Remember what this tool is not: anything flexible — spans past ~150 m, tall slender piers during staging, cable-supported decks — falls under aeroelastic effects (3.8.3), where buffeting and vortex response are analysed, not looked up. Staging cases with bare girders before the deck often govern the substructure and are worth a separate run with the full exposed depth of the girder line.