Diaphragms to Girders Connection Effect on the Rotation of Exterior Girders during Construction

Rotation of exterior girders during bridge deck construction is an issue that many Departments of Transportation (DOTs) around the U.S. are facing. The transverse bracing systems are commonly used to resist the torsional moments resulted from the deck construction loads. This study focuses on the bracing systems including diaphragms and cross-frames, and it targets the different methods used for connecting the diaphragms to the steel girders. Finite element (FE) models are developed to assess the differences among these connecting methods. The results showed that for bridges with diaphragms, using welded connections generally reduces the rotation. On the other hand, using bolted or welded connections in bridges with cross-frames has minimal effect on the rotation. It can be concluded that the effective height of the connection member is the major factor that affects the rotation of the exterior girder due to construction loads.