Deck Forms for Bridge Construction Safety

Because I-girders have inherently weak torsion resistance, cross-frames and/or diaphragms are placed at close spacing intervals to minimize the susceptibility of individual girders to instability during construction. A recent increase in fatigue problems around discrete brace connections, along with the costs of fabrication, erection, and inspection associated with cross-frames, has prompted the removal of the minimum-spacing requirement from bridge specifications and created interest in identifying alternative construction bracing approaches. Although permanent metal deck forms (PMDF) are widely used in the construction of steel bridges today, the stability they provide is not considered in construction-sequence engineering. Other researchers have investigated the stability that PMDF provides during the construction of bridges of moderate span length. The overall objective of this project was therefore to improve bridge-design efficiency and construction safety by developing strength definition and engineering methodology that considers the contribution of PMDF to stability during the construction of long-span deep steel plate girder bridges. Global tasks included the following: (1) synthesizing all relevant literature; (2) synthesizing state-of-the-art design and construction practice relevant to PMDF, including connection details; (3) developing preliminary engineering approach and concepts and identify research focus; and (4) using advanced finite element methodology to develop and verify proposed design methodology.