As defined in Wind Load on Substructure, the wind angle is the angle between the normal to the longitudinal direction of the bridge and wind direction, positive if anti-clockwise, measured from the normal of the bridge to the wind direction. The wind load on live load depends on the wind angle and live load length. It is calculated by multiplying the wind pressures in transverse and longitudinal directions with the live load lengths. Then, it is resolved into pier cap X and Z-directions (global coordinates) if the bridge is on skew.

The wind load acting on the live load is equally distributed among all bearings in the global X and Z-directions. The wind load also produces a moment due to the wind load acting above the bridge deck (e.g., 6 feet above the deck). This moment will result in a couple acting on the exterior bearing points at two ends of the pier and is applied as loads in global Y-direction.

The wind pressure on live load at 75 degrees is extrapolated from those for wind pressure angles from 0 to 60 degrees.