American and Japanese design and detailing practices of prestressed concrete box girder bridges are compared. A new precast, prestressed box girder bridge design suitable to U.S. practice is proposed. The design is based on requiring the deck to act as a rigid assembly of longitudinal and transverse members. This is consistent with Japanese practice and fulfills the intent of several state DOT initiatives. The proposal advocates quarter-point diaphragms with relatively large amounts of transverse post-tensioning. A design chart and recommended details are provided for bridges up to 80 ft (24 m) long. The amount of post-tensioning was found to be unaffected by bridge span length. Also, a comparison with the requirements of the AASHTO LRFO provisions is given. A fully worked numerical design example is included to demonstrate the proposed design procedure.
