Geometric Constraints
Minimum flange width is 0.20D, where D = web depth, but not less than 15 in.
Minimum flange thickness is 0.75 in.
Minimum web thickness is 0.50 in.
Minimum stiffener thickness used to connect cross frames or diaphragms to girder is 0.50 in.
Satisfy the span-to-depth ratios in Article 2.5.2.6.3 as a minimum, unless vertical clearance constraints demand a shallower superstructure.