Abstract
The provisions of the 2004 AASHTO load and resistance factor design specifications for steel I- and box-girder bridge design have been updated relative to previous specifications to simplify their logic, organization, and application and to improve their accuracy and generality. These provisions provide a unified approach for the flexural design of both tangent and curved I- and box-girder bridges. Updated resistance equations are a key component of this unified approach. An overview is provided of the updated resistance equations for I-section members. The primary focus is on handling coupled major axis bending, minor-axis bending, and torsion from any source in both straight and horizontally curved I-section members.