STIFFNESS REQUIREMENTS FOR METAL DECK FORMS USED FOR STABILITY BRACING OF STEEL BRIDGE GIRDERS

摘要

Permanent metal deck forms (PMDF) are frequently relied upon for bracing in the building and bridge industries. In the building industry the forms are typically modeled as a shear diaphragm that restrains the warping deformation of the girders' top flanges. The forms in the bridge industry differ from those used in the building industry primarily in the methods of connection to the girders. This paper reports results from a research investigation on the bracing behavior of PMDF used in the bridge industry. The study has focused on improving the PMDF connection details, while also improving the understanding of the stability bracing behavior of shear diaphragms systems. Recommendations from the study are currently being implemented in the design and construction of two bridges in Houston, Texas. This paper focuses on the results from a parametrical study to determine the brace stiffness requirements for PMDF used for stability bracing of steel bridge girders. Both eigenvalue and large displacement finite element analyses results are presented. In addition, results from large displacement finite element analyses are compared with laboratory buckling test results of a 50 ft twin-girder system braced by PMDF.