AASHTO LRFD Bridge Design Specifications, Customary U.S. Units, 4th Edition (Includes 2008 and 2009 Interim Revisions ***Note: SI Edition only has 2008 Interim Revisions) and AASHTO LRFD Bridge Design Specifications, SI Units, 4th Edition
standard by American Association of State and Highway Transportation Officials, 01/01/2007
