Uniform Live Load:
Pedestrian bridges shall be designed for an evenly distributed live load of 85 pounds per square foot (psf) of deck. When the deck area exceeds 400 square feet, the load may be reduced in accordance with the following formula.
W=85(0.25 + 15/(a^.5))
W = Pedestrian Load (psf) A = Deck influence area
The reduced design load shall be no less than 65 psf.
Pedestrian bridges with the occasional slow moving maintenance or emergency vehicles, impact is not required.
Vehicular bridges will also be designed to withstand a moving concentrated load of a vehicle weighing 1000 pounds per foot of bridge width (up to 10,000 pounds).
For bridges used where snow removal is a concern, the vehicle load shall be in addition to a 20 pounds-per-square-foot, evenly distibuted, live load. The vehicle load shall be distributed such that 80% of the load is on the rear axle per (AASHTO).
All bridges shall be designed with a minimum wind load of 30 pounds per square foot on the full vertical area of the bridge.
The vertical deflection of the truss due to pedestrian live load shall not exceed L/500. The deflection due to vehicular loads shall not exceed L/800. For pedestrian comfort, the minimum live load used for the deflection check shall be a minimum of 600 pounds per lineal foot of the bridge. The horizontal deflection due to lateral wind load shall not exceed L/500 of the span length.