I've used a couple of references:
"Orthotropic Bridges, Theory and Design"
By M.S. Troitsky
Published by The James F. Lincoln Arc Welding Foundation.
"Design Manual for Orthotropic Steel Plate Deck Bridges"
Both were fairly good references, although the AISC publication is a bit old
Then there are several papers floating around by R. Wolchuk, R. Meyrbal and
Hope this helps.
Tom Cummings, PE
Senior Structural Engineer
URS Greiner Woodward Clyde
It's refreshing to see bridge related questions now and again.