Skewed Cross Frame Connection Stiffness

Abstract

Cross frames and diaphragms are essential to the stability of straight steel girder bridge systems as they help to resist lateral torsional buckling during construction and horizontal loading conditions. In skewed bridge systems, cross frames are often oriented parallel to the supports and hence, at an angle to the girder. To facilitate construction fit-up, plates, bent to match the skew angle, form the cross frame to stiffener connection. While the bent plate connection is a simple solution, it could introduce undesirable flexibility into the system, potentially compromising the effective brace stiffness. A proposed detail utilizing half pipe stiffeners may provide enhanced structural performance, while possibly reducing overall fabrication costs. Field and laboratory tests to determine the stiffness of both connection types are presented in the thesis.